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   Over the last 5 years I've been working on some of my own engine designs. I looked at just about everything avalible on the Bob O'Neal designs and have been disappointed with many peoples explanations on how this engine runs. 
   Even though it said in the patent [ compressor ] that does not mean it runs on comprest air.  If you look closely at the drawings , you will see the check valves,  will not let compressed air into the cylinders.
   It takes much less work to pull a vaccume to do work , than try to compress volumes of air to do the same work. Compressed air in this operation is the waist product [exhaust] . This doest not mean we do not use some of this waist exhaust.   

    If their is more intrest this topic let mo know  via e-mail , Mike                             
   

Hi Motorcoach1,
your opinion is very intersting. I know the Bob Neal patent. I studied it years ago. But does not know if it works. Later I found the side of Scott Robinson (aircaraccess.com). I think you know them too. He seems to be very busy but could not replicate the Neal engine. It could also be that the Neal engine never worked ... :( Because there are tons of patents out ...

Greetings
Alana

Quote from: Motorcoach1 on December 25, 2012, 03:33:33 PM
   Over the last 5 years I've been working on some of my own engine designs. I looked at just about everything avalible on the Bob O'Neal designs and have been disappointed with many peoples explanations on how this engine runs. 
   Even though it said in the patent [ compressor ] that does not mean it runs on comprest air.  If you look closely at the drawings , you will see the check valves,  will not let compressed air into the cylinders.
   It takes much less work to pull a vaccume to do work , than try to compress volumes of air to do the same work. Compressed air in this operation is the waist product [exhaust] . This doest not mean we do not use some of this waist exhaust.   

    If their is more intrest this topic let mo know  via e-mail , Mike                             

I might be interested in discussing this here as I do have an interest in the topic, but why "via e-mail" ?

And anyway, it does not appear that you have provided any e-mail, here or in your profile.

  [ personal messages get forwareded to my e-mail ]

  Thank you for the intrest in this subject. I'm sure most have studied the patents and know some history about this type engine. All I can say is patents do not contain Intaulectual Property.

  Ok lets get started on how I belive the air cycle works in [ 1 ] cylinder.

   We will start the cycle with the piston at BDC [ bottom dead center ]
   1- A vacume is now pulled in the cylinder pulling the piston up. As the piston is at TDC [ top dead center ] it will pull the strongest vacume. At this time the check valve in the head opens for about 1/5 of a second { based on 120 rpm's runnig }

   2- Say we have 3 cubic inches in the cylinder and that is being evacuated , as the piston reaches TDC and pulls full vacume the valve opens [ vaccume break ] and shuts within the 1/5th second we now have 3 and 1/8 cubic inches of air evacuared.  Maybe a little more air.

   3- Now that evacuated air is quite cold , cold air is dence and takes up a lot less space than hot air, and store it for future use say in 2 or 3 minutes.

Lets go back to the head check valve opening for that 1/5 second.  As we evacuated the cylinder , we did not get all the ambiant air. The rest left in the cylinder is now an air spring to work for us at BDC. in the UP stroke.

WILL COVER THE BOTTON PISTON STROKE IN ANOTHER TRANSMISSION . See if you can find maxwells demond in this thread.

Cheers Mike
PS; be nice or be gone you have been warned .................

   

    This is part 2

  The ICE engine is a brute force combustion . The same engine modifed is more of a dance.

  1- We are at the TDC and returning the piston to BDC . Now lets take a look at that 1/5sec ambiant air intake [ the part that did not get evacuated ] . This is the eqlizer air spring keeping the piston floation as it hits BDC. or other wise keep things from collideing .
  2- During the pistion travel to BDC , it is being evacuated as in the up stroke , it has the little 1/5 damper [ air spring ]

  3- As the piston reaches the BDC stroke , we have our compressed air valve. [ remember that 1/5sec  ? , that cold air went to our insulated tank for future use ]
      Now we need to start the dance.

  4- We take some very cold condenced air from our insulated tank and as Bob Neil does [ but not in the patent ] we heat this air to inject in the BDC stroke to push the piston up.
      This has to be done at equal pressures on both sides of the piston [ the evacuated side as well as the pressure side ]- we have more compressed air at thie time than we can use so bleed off is nessasry. Remember no more compressed air than is nessary - the dance !

  AlanA ; I hope this answers your question about some of the workings on the tank.

  I hope to be building a working prototye soon , 1 cylinder runner.
  I have a line on good gast vane pumps cheep so send pm for info if you are building.

  thanks Mike        I use the kiss method.

here some info on air engines

Pleas post all question and comments in fourm as this will be open source invention

Thanks Mike

We need someone who has a good workshop to prove all this theories. There are too much papers out there ...

P. S. The inventors name is Bob Neal  ;) .

In looking over the patent application, there are a few things I find somewhat puzzling which lead me to wondering if there are not some intentional blinds and/or omissions.

1. There doesn't seem to be any account of any exhaust from the power cylinders. That is, there are inlet ports and an outlet port, but where exactly the outlet port goes is not specified, as far as I can see. After driving the piston, does the compressed air get vented to atmosphere or is it recirculated back to the tank or what ?

2. There is an electric generator that powers some electric heaters situated at the power cylinder inlet, supposedly to bring the incoming air up above freezing ? This seems rather extraordinary to me. Why would the air from the tank be so cold ?

3. There is a water (cooling jacket) surrounding the compressor pistons. There are two water pumps with inlet and outlet pipes shown. It can be assumed, I suppose, that the hot water goes to some sort of external radiator to be cooled by the fan. The first illustration of the engine suggests that the water jacket probably continues to the front and around the power cylinders as there is no step in the side. That is, the jacket appears to be continuous but in the drawing of the power cylinders no water jacket is shown surrounding the power cylinders.

Anyway, after looking at all this for a while, I came up with an idea as to how this thing might work, but it is quite different from what is generally assumed, and it would depend upon the idea that there are some intentional omissions from the patent. That is, there was some intent to hide or keep secret the true mode of operation which, if I'm right, had nothing to do with any "special valve" or "equalizer" but rather with how this engine recirculates heat.

Anyone who has used an air compressor is no doubt aware of the tremendous amount of heat generated.

The water surrounding the compressor cylinders, we might assume, is scalding hot. Possibly superheated.

Apparently, for reasons to be touched upon later, the air in the tank is extremely cold.

Suppose this engine is not running on "compressed air" from the tank at all ?

Rather, VERY COLD air is being injected into the power cylinder and EXPANDED.

That is, the heat generated by the compressors is being circulated through the water jacket to heat the power cylinders. The cold air that enters the power cylinders picks up heat from the scalding hot water in the water jacket and expands rapidly.

This would mean that the ambient heat driven off from the air being compressed is being used to drive the engines power pistons.

It is fairly well known that when air is expanded while doing work at the same time it can get very very cold when exhausted.

If this cold air from the power pistons is being sent back to the air tank it might explain why the air coming back from the tank is so cold.

The reason then, that the air can be pumped back into the tank is not because of any special valve or any resonance or pulse jet effect or anything of the sort but simply because the engine is not running on compressed air at all. The tank is simply a COLD AIR STORAGE TANK. The pressure then, would be just enough to keep the air moving along. Pumped rather than actually pressurized.

The pressure to run the engine is developed AFTER the air enters the power cylinder. It is expanded by the heat generated by the compressors, delivered by the circulating hot water in the water jacket.

This is of course, speculative, like any other theory about this engine, but it makes sense to me. It is also not outside the realm of possibility in that no actual radiator or cooling system is shown. It might be assumed that the hot water taken from the compressor cylinders is actually cooled by being delivered to the power pistons to heat up and expand the apparently, very cold air returning from the tank so that no radiator is actually necessary.

As no account is given as to what happens to the very cold air leaving the power cylinders, it might be assumed that this goes back to the tank, which would explain why the air coming back from the tank is so extraordinarily cold as to need pre-heating by electric heaters just to bring it up above freezing.

In other words, the engine is not running on compressed air at all but rather on the ambient heat extracted while air is being compressed. The compressed air then would be available for other uses (the auxiliary tank briefly mentioned) while the cold air from the engine is simply being recirculated rather than compressed.

Quote from: Motorcoach1 on December 25, 2012, 03:33:33 PM
   Over the last 5 years I've been working on some of my own engine designs. I looked at just about everything avalible on the Bob O'Neal designs and have been disappointed with many peoples explanations on how this engine runs. 
   Even though it said in the patent [ compressor ] that does not mean it runs on comprest air. If you look closely at the drawings , you will see the check valves,  will not let compressed air into the cylinders.
   It takes much less work to pull a vaccume to do work , than try to compress volumes of air to do the same work. Compressed air in this operation is the waist product [exhaust] . This doest not mean we do not use some of this waist exhaust.   

    If their is more intrest this topic let mo know  via e-mail , Mike                             

Your comments about the check valves and how the engine apparently is being used to "pull a vacuum" got me thinking along different lines.

There is nothing, as far as I can see, telling where the water to chill the engine is coming from. For the sake of argument, lets say that the engine is circulating extremely cold water being drawn from a cold running stream.

What you say about the valves appears to be true. The engine is not compressing air. On the contrary, at least at one part of the cycle, it is, as you say "drawing a vacuum". Or rather, mechanically EXPANDING the air.

The valve at the top of the cylinder has what appears to be a very stout (strong) spring holding the valve closed. There is no valve lifter to open and close the valve. Therefore what this amounts to is a "throttling valve". At the same time the piston is going down expanding the air in the cylinder. Simultaneously the air is being chilled. Put all these processes together, Throttling, Mechanical expansion, and cooling, and what this is starting to look like is not a compressor at all but rather an Air Liquefaction machine.

All of these processes, rapid expansion, throttling and cooling are processes that are used for the liquefaction of air.

http://en.wikipedia.org/wiki/Liquefaction_of_gases

At a minimum, it seems that the combined effect would result in, if not actual liquefaction of the air, extreme COOLING of the air, which would result in its contraction. The air then is not being forcefully compressed, but rather COOLED to an extremely low temperature which could very well result in its condensation into a liquid.

If this were the case, of course there would be no possibility of the HEAT generated by compression being used for the power cylinders. There wouldn't be any heat generated by such a process of cooling by rapid expansion. But then, if the engine is cooling the air to such extremely low temperatures then there wouldn't be any need for using any such heat.

What you would have, in effect, would be a liquid air engine.

The liquid, or near liquid air delivered to the tank would pick up ambient heat causing the liquid air to "boil". Ambient heat alone would be enough to create the necessary pressure to drive the engine, possibly supplemented by the electric heaters at the air inlets of the power cylinders.

Here is an interesting article explaining how liquid air can be used to run an engine:

http://www.unz.org/Pub/McClures-1899mar-00397 (http://www.unz.org/Pub/McClures-1899mar-00397)

One other thing that crossed my mind:

If any of the above speculations are even remotely accurate. That is, if the engine is delivering very cold air to the tank, which seems evident from the patent, (air coming from the tank is described as being below freezing) then I think this might explain how the "equalizer" works.

Liquid air would be around (minus) -196 degrees celsius ( - 320 F ).

If during 1/2/ the cycle the compressor were making liquid air and during the other 1/2 cycle cold compressed air, and these were mixed together and delivered to the tank the temperature of the air going to the tank could be as cold as -150 degrees Fahrenheit. Just to give us something to go on.

At any rate the air going to the tank would be darn cold.

The tank is sitting there surrounded by ambient air, so it would be warming up.

I'll call what goes from the engine to the tank "liquid air" though I doubt that would be the case, more a mix of cold compressed air and possibly liquified air. But any way, this very cold "liquid air" goes through the first check valve of the equalizer at say -100 degrees Fahrenheit. It would, presumably, immediately begin to warm up and expand as the air already in the tank would be considerably warmer. As the cold air, having passed the first check valve gets warmer and expands it would have nowhere else to go but into the tank.

As the air in the equalizer expands and does the "work" of pushing the air out into the tank, the air left behind, still in the equalizer would loose energy. It would tend to cool and contract, drawing more "liquid air" through the first check valve.

In other words it would act like a thermal expansion pump. Cold air goes past the first check valve, warms up, expands and pushes some air through the second check valve, contracts and draws in more cold air through the first check valve. Something like a coffee percolator.

I stand corrected it's Bob Neil , no O .
Tom I stand with the same anoligy as you on the opperation. As for the exaust porting I'm just as puzzled.
I understand most patents are not complete or things get ommited.
To take the exhaust porting one step farther , I was looking for a weak spot in the piston movement. As the piston moves to mid point in the cylinder , there is chance of netural vaccume on both sides of the piston. So adding in a compressed hot air valve to the bottom of the cylinder would assist the piston in the up stroke , not affecting the evacuation process of the down stroke.
This would mean 2 evaccuation strokes, 1 up, 1 down and 1 compressed air assist , completing the cycle in one cylinder.

Could not get the McClure file to open , if you have the PDF , please post it . Thanks Mike

Quote from: Motorcoach1 on December 25, 2012, 03:33:33 PM
      It takes much less work to pull a vaccume to do work , than try to compress volumes of air to do the same work. Compressed air in this operation is the waist product [exhaust] . This doest not mean we do not use some of this waist exhaust.   
 

Interesting discussion of the Neal machine, thanks Motorcoach.  I have a question about the above statement regarding work to pull a vacuum vs compress air.  Since 1 atm is at 14.7 psi, then any possible vacuum is limited to a pull of less than this amount of psi.  If a compressor is likewise limited, then it seems that the work for either choice would be equal.  Since the amount of energy stored in the air for use in a machine would be measured by how far the air pressure is moved away from 1 atm, it seems that positive pressures would be capable of much higher energy storage, since they are not limited in the extent of pressurization.  If the vacuum or compression are both within 14.7 psi of 1 atm, then either method would be capable of providing the same work.  Does that seem like a correct statement?

Quote from: Tom Booth on December 30, 2012, 02:18:37 PM
1. There doesn't seem to be any account of any exhaust from the power cylinders. That is, there are inlet ports and an outlet port, but where exactly the outlet port goes is not specified, as far as I can see. After driving the piston, does the compressed air get vented to atmosphere or is it recirculated back to the tank or what ?
2. There is an electric generator that powers some electric heaters situated at the power cylinder inlet, supposedly to bring the incoming air up above freezing ? This seems rather extraordinary to me. Why would the air from the tank be so cold ?
3. There is a water (cooling jacket) surrounding the compressor pistons. There are two water pumps with inlet and outlet pipes shown. It can be assumed, I suppose, that the hot water goes to some sort of external radiator to be cooled by the fan. The first illustration of the engine suggests that the water jacket probably continues to the front and around the power cylinders as there is no step in the side. That is, the jacket appears to be continuous but in the drawing of the power cylinders no water jacket is shown surrounding the power cylinders.

Hello Tom,  this is an interesting discussion on Neal.  Here are some comments, what do you think?
1.  Most likely the power cylinder exhaust exits to the rear of the motor block, to the atmosphere.  It is drawn as the small square shape on figure 3, within the slide valve chamber.  On the left side of figure 3, the number 62 has an arrow leading to it.  This was identifed to me several months ago by a steam engine man, over at the Aircaraccess site.  Apparently this is how steam engines were constructed.
2.  Another explanation might be the use of a pre-heater, as is described in the old texts on compressed air engines.  Supposedly preheating the air produces more engine power with less input energy, as compared to simply compressing the inlet air to a higher pressure.  This method would provide higher efficiency.  Regarding item 3 below, if there is heat generated in the pipes, then that heat will be lost, which will result in a slow cooling of the block since the heating and cooling are no longer equal.  The electric preheater can be used to bring that back into balance.
3.  Since the machine includes both power expansion cylinders and compression cylinders, and each will provide the opposite temperature effect, then possibly the circulating water jacket is self contained within the block with no external radiator.  This would equalize all the temperatures, and save all energy that is flowing via heat within the block.

   Been doing some more reaserch here. In the  quote [ combination fluid operated engine and compressor ] at the start of the patent.

After doing some reaserch from what Tom has mentiond , due to the fact ' fluid operated ' was in the patent. this shed more light on this engines machenical parts and their funtion.

  Lets start the engine in our minds eye........

First we turn on the start resivore tank [ this is not the eqlizer tank ] . this tank is just for starting the engine. We push the start valve , this turns the airmotor starer at the flywheel. This air motor turns over the engine slowly for say 2 to 4 minutes.

                           Now we ask why so long ?

   When we first start the engine it is all in compressor mode, all 10 compounded cylinders an the 2 pistion cylinders. What happens within the next 2 to 4 minutes is somewhat of a metmorphsis.  As the engine is turning over pressure and vacumes are exchanging placeses. As the tempeture differentals build to the desired levels P & V swap sides and the equlizer valve is in full operation at a high occillation [ as Tom said liqfacation or close to it ] . What is now the 10 cylinders that started in compression swap to vaccume pull and the 2 pistons swap to pressure push.
I belive the center tube connectting the 10 cylinders would be larger to acommadate a high speed venture valve to get the tempatures down even farther than the porting from the cylinders directly.  One other thing happens also is the generator kicks on for the heaters .

Quote from: Motorcoach1 on January 03, 2013, 05:18:27 PM
   Been doing some more reaserch here. In the  quote [ combination fluid operated engine and compressor ] at the start of the patent.

After doing some reaserch from what Tom has mentiond , due to the fact ' fluid operated ' was in the patent. this shed more light on this engines machenical parts and their funtion.

The term "fluid" is used in the scientific world to imply fluid dynamics, which is not to imply liquid as in solid-liquid-gas.  It may be that Bob Neal is using the proper scientific use of the word fluid, which implies changing pressures and velocities of a gas.
For an alternate explanation of Bob Neal, see the discussion at:
http://aircaraccess.proboards.com/index.cgi?board=tank&action=display&thread=78
You might find some interesting reading there.

Quote from: Joe1 on January 09, 2013, 11:28:13 PM
The term "fluid" is used in the scientific world to imply fluid dynamics, which is not to imply liquid as in solid-liquid-gas....

That was my understanding when reading the patent. fluid = gas.

What puzzles me is the inlet valves (on top of the compression cylinders). If the purpose was simply to provide an inlet for air to be compressed, why not just use ordinary check valves as elsewhere? Using strong springs would tend to severely restrict air flow into the compression cylinder which would just put an unnecessary strain on the engine to open such valves. Of course, just how strong the springs may have been is guesswork. The patent lacks detailed specifications.

I tend to very much doubt that liquefaction of air could be achieved in one stroke of a piston in such a manner, but without an actual change of state, the strong valve would just put a strain on the compressor to no end, as far as I can see. If it were possible (change of state to a liquid, or at least a vapor mist), once liquified there would be a tendency to remain liquid, at least long enough for the chamber to be evacuated. That would serve some purpose.

Air can and has been liquified using some rather crude apparatus.  Some early air liquefaction machines look almost like an apple press with just a hand cranked wheel to do the work. I think Lind liquified air continuously and in some volume with just a 3 horsepower engine with only water cooling, though the air was recirculated, compressed and cooled repeatedly.

I have some doubts about it but I think the formation of a MIST of partially liquified air might have been possible with such an engine. At any rate, it seems to be suggested by the construction, given the apparently strong valves used, rather than simple check valves.

What got me thinking along these lines is the reportedly "below freezing" temperature of the air in the tank. Was this engine intended for use in some situation where the ambient temperatures would be so cold ? Possibly, but I hardly think so.

One other thing that puzzles me is the report that he made a small model to take to the patent office. Setting it on the desk of the patent examiner. If this thing required water cooling to operate, how would that have been accomplished at the patent office without a source of water for cooling? Tap water from the sink ?

I have been thinking of a means of testing this idea of running an engine by "pulling a vacuum" using a small model, like a Stirling engine.

I may post something on that in the next day or two.

I thought it might be interesting to compare the Lind Air Liquefying machine with Neal's Air compressor/engine.

There are several apparent similarities or corresponding components. Of course there is an air inlet, a compressor, a water jacket or cooler, a storage tank for the compressed/liquified air, and Lind's machine has an adjustable throttling valve.

And some differences. Lind's machine did not use mechanical expansion. Rather the air was first compressed and cooled and then allowed to expands through the valve into the tank where it then became liquid. Lind's machine also recirculates, re-compresses and cools any air from the tank that fails to liquify in previous cycles.

Neal's engine combines the various elements in one machine rather than having the components separated, Also, the function was different. Lind's object was simply to liquify air whereas Neal's was power production.

We might imagine Lind's machine utilizing the liquified air from the tank to in turn run an engine to run the compressor.

Anyway, here is an illustration of Lind's Machine:

OK here is my idea for a relatively simple way to test this theory that an engine might be able to run (on ambient heat) by "pulling a vacuum". (Along with simple water cooling.)

It may not actually say much about the Neal Compressor or engine itself, but at least it might demonstrate the basic principle.

There are a few different possible variations.

The basic idea though is to use a "throttling valve" to create a partial vacuum for cooling so as to create a temperature difference. The cold produced, theoretically, making it possible for an engine to run on ambient heat.

In this case I'm using a conventional "Low Temperature Differential" Stirling for the sake of simplicity as well as to avoid some of the problems involved with the possibility of building a Neal type engine, besides the cost and complexity of building such an engine, by using a Stirling Engine the cold produced could be used directly, obviating the need for a storage tank and the problem of how to get low pressure air into the tank, the "equalizer" and all that.

Today, a "throttling valve" is less frequently used as it has been found that an expansion turbine is more effective, so there are two versions, one with a valve similar to the one in the Neal Compressor and another where the valve has been replaced by a turbine.

The valve stem is threaded so that the spring tension is adjustable.

Similarly, the turbine has a brake so that resistance can be placed on the turbine. The more pressure applied to the brake, the more the "throttling" effect and the greater the cooling effect. Making these adjustable allows the engine to at least run (hopefully) and then the "throttling" for cooling can be applied gradually to whatever degree the engine might be able to handle.

I'm using a clay pot for the water cooler. It could be filled with ice water, but I think there is a chance that it would provide sufficient cooling with just evaporative cooling.

Also some heat source, like a block of heated metal is shown to get the engine started and provide a temperature differential until some cooling can be effected.

Basically you have a simple LTD Type Stirling Engine sitting on a cooling plate or simple "refrigerator" and, theoretically, if enough cold is produced by "throttling" then the engine could continue running and powering its own cooling system by utilizing ambient heat.

Eventually the heat source (block of metal or "starter") will cool off to ambient temperature or could be removed. The ice would melt and it could be seen if the "throttling" or "pulling a vacuum" provides enough cooling by itself to keep the engine going without these.

Here is one more version that allows for some additional pre-cooling of the air before being "expanded" by utilizing some of the cold from the air that has already been cooled.

Quote from: Tom Booth on January 11, 2013, 07:38:54 PM
What puzzles me is the inlet valves (on top of the compression cylinders). If the purpose was simply to provide an inlet for air to be compressed, why not just use ordinary check valves as elsewhere? Using strong springs would tend to severely restrict air flow into the compression cylinder which would just put an unnecessary strain on the engine to open such valves. Of course, just how strong the springs may have been is guesswork. The patent lacks detailed specifications.

I certainly agree with your comments about the odd inlet valves at top of compressor cylinders.  Some other possible explanations might be that there is not enough vertical space in the head piece to fit a ball valve as used elsewhere.  Another could be that he could remove the upper inlet valve and run the engine with half the inlet air, using single acting pistons instead of double acting.

Your posts regarding the cooling and stirling references are interesting and worth some study time.  One thought I have is that Neal does mention that the compressor is working against only 15 psi, which to me implies there would be little heat generated in the compressor cylinder.  Over time with the engine running, it seems there could be a trend toward cooling so that the tank air would begin to cool down.  Not necessarily as the main working principle, but as a side effect.

From what little I know of Stirling engines, the temperature differential is directly related to the amount of work that can be produced by the engine.  The LTD stirlings will just barely turn a light crankshaft.  Neal would need a high temp differential to turn his crankshaft.  It does not seem like that requirement would result in an overunity effect, since much energy would be needed to develop the high temp diff in the first place.  But as you have mentioned, possibly he left that part out of his patent.

Thanks so much for the posts and diagrams, which will keep me busy with study.

Quote from: Joe1 on January 15, 2013, 10:05:59 PM
... Stirling engines, the temperature differential is directly related to the amount of work that can be produced by the engine.  The LTD stirlings will just barely turn a light crankshaft.

I think the advantage of the LTD Stirling is that it CAN or is able to run on a very low temperature difference, as little as 5 or 6 degrees Fahrenheit due to the very large surface area, but I don't think it is limited to running on a Low Temperature difference. I suspect with a higher TD it could put out power comparable to other Stirling Engines.

As it is, we don't yet know what the effect of "pulling a vacuum" to create a TD would be. If it were possible for the Neal engine to realize what I guess would be the ideal... actual liquefaction of the air, the amount of liquid air produced from each cylinder would no doubt be miniscule. Perhaps just a tiny droplet or a mist, but there are so many cylinders working together and continuously...

When air actually liquifies, so I've read, it takes on a "spheroidal state" and even in a high temperature environment tends to persist. Surrounding itself with a protective, insulating vapor. This is similar to splashing a drop of water on a very hot skillet. Rather than evaporating from the heat, the drop of water will dance around on the skillet on a layer of water vapor. I can imagine such droplets of liquid air traveling down the common pipe to the "equalizer" then into the tank.

If this were possible, Air, when it expands from a liquid increases in volume 800 times. In other words, a very small amount of liquid air could easily fill an air tank.

The same principle for COOLING air, when taken to extremes will also liquify air.

Most of the early difficulties involved in liquifying gases were due to ignorance regarding critical temperature. It was found that compression, no mater how extreme just didn't work. The "permanent gases" that were considered "impossible" to liquify were found to be relatively easy to liquify when cooled. In other words, cooling is a more effective way to "compress" air than actual compression.

As you point out, the Neal engine was only supposed to use 15 PSI which is practically no compression at all. Logically, it seems to me, extreme cooling would be the only viable substitute for actual compression.

Historically, I think it is also interesting that Neal completed work on his engine and filed the patent not too long AFTER the period of time when Trippler was liquifying air in great quantities and very inexpensively, primarily using cooling rather than high compression, and created quite a stir about the possibility of running engines on liquid air. 

QuoteNeal would need a high temp differential to turn his crankshaft.  It does not seem like that requirement would result in an overunity effect, since much energy would be needed to develop the high temp diff in the first place.  But as you have mentioned, possibly he left that part out of his patent.

A high temperature difference can be arrived at in two different ways. Heating something above ambient, OR cooling it far below ambient. You don't necessarily need to have an availability of an extremely cold sink to get extremely cold temperatures since this can be arrived at by mechanical means. Trippler liquified air in enormous quantities with nothing more than the availability of cold river water for cooling, the rest of the cooling was mechanical, compression and expansion.

Of course, I'm just speculating. If the Neal engine actually worked, including the small model he took to the patent office, I can't help but wonder what happened to these engines.

Recently I've been wondering what happened to Trippler. He seemed poised at one point to bring about a revolution. He seems to have proved that an engine could very well run on liquid air and that the liquid air itself could be produced in quantity at very little cost, then what ?

Quote
Thanks so much for the posts and diagrams, which will keep me busy with study.

One thing about the diagrams. It is a minor point and I was going to fix it but I didn't realize it until after I could no longer edit my posts. But the "vacuum pump" is wrong. That is, the placement of the check valves makes the pump non-functional. I don't see any need to re-upload all of them I'll attach one image with the valve relocated.

Anyway, using the LTD engine would, I think be an advantage as it is not so demanding, as far as temperature difference requirements. But it could be made to operate on the same principle which if taken to extreme might be used to run a larger engine, like the Neal engine.

In other words, the same principle used to run the LTD engine on slightly cooled air could theoretically also run the Neal engine if the cooling were taken to the point of liquefaction.  I very much doubt it would work otherwise. That is, without an actual change of state the air would just be expanded in the cylinder and then compressed back down before it left the chamber. As far as I can figure out, that would serve no purpose. But if even a very small quantity of the air actually liquified and condensed into the "spheroidal state" then it could accumulate and be moved into the tank. The change of state, I think, would be very important in the Neal engine for it to function, but a change of state would not be required with the LTD engine, though the same principle is involved.

In other words, if the LTD engine could function as illustrated then I think that this would lend some credence to the idea that this is how the Neal engine may have functioned in principle as the method used for cooling is the same as that used in gas liquefaction. It would just be a mater or taking it a step further. A greater degree of cooling using the same or similar method.

This is a very interesting discussion.  Do you have any links where I could learn about Trippler?  Tried the Google patent inventor search, but nothing there.  Many Thanks.  Are there any patents associated with Trippler?  Do you have a first name, or did he publish any papers or descriptions?

When you refer to the spheroidal shape, sounds like that would be similar to supersaturated water.

Here we go,
http://archive.org/details/liquidairandthel033169mbp
See Chapter XII.

Thanks for the very interesting discussion.
I found the patents of Charles E. Tripler very easy (google patent search).
There are various patents from Tripler. Two are from 1900:
- US 652.058, Liquefier for atmospheric air
- US 652.304, Liquid-Air generator.
I also found a very remarkable detail about Tripler. In 1901 it seems that he has invented a car that was propulsed by liquefied air. But I have not found further details about it :((

But could it be really efficient to liquefy air? I think there must be a lot of energy to get this kind of air. Tripler compressed the air with 2500 pound.

Quote from: AlanA on January 20, 2013, 05:02:53 AM
I also found a very remarkable detail about Tripler. In 1901 it seems that he has invented a car that was propulsed by liquefied air. But I have not found further details about it :((

But could it be really efficient to liquefy air? I think there must be a lot of energy to get this kind of air. Tripler compressed the air with 2500 pound.

There are a lot of articles from the NY Times Newspaper available on Google about Tripler and his Liquid Air Company. I haven't read all of them but what I've gathered so far he had plans of manufacturing all kinds of engines to run on Liquid air.

I don't think there is any doubt that he was making huge quantities and shipping it all over the country.

He claimed, according to that article, to be able to use liquid air to run his compressors to make more liquid air. That he got 10 gallons of liquid air out of his liquifier for every 3 gallons he used to run the machine.

I think that this was possible because his plant was located on a river into which a lot of heat could be dumped for free. He compressed the air which got it hot then cooled it with river water then let it expand so it got extremely cold then used the very cold air that resulted to pre-cool more compressed air so that the temperature kept dropping. The point to be noted is that he was getting the cold river water for free. It would not be possible to do this with an engine running in a car for example as you can't travel around in your car with a river.

It looks like there was a lot of controversy. Several US senators joined the company. Then accusations of fraud. Scientists were writing articles denouncing his claims, then some scandal involving the disappearance of investors money.

The company was apparently going strong shipping barrels of liquid air all over the continent in 1900 - 1901. By 1902 the company collapsed in bankruptcy. There was apparently some kind of official inquiry into the collapse. What the conclusion, if any, I haven't found out. He died just a few years later in 1905.

I'm not really sure if this makes sense or not or if it is even possible or effective but I had another idea about the possible purpose of the "throttling valve" that would not necessitate actual liquefaction of the air but would still be useful.

Perhaps the purpose of expanding the air in the cylinder for cooling (if that was in fact the purpose) was not so much to cool the air itself or liquify it, as I think in such a process, very little air would actually be drawn in, but to pre-cool the cylinder itself.

The same cylinders are used for expansion/cooling and compression.

Perhaps the idea was to fist expand some air by  "throttling" or the "Joule - Thompson Effect" in the cylinder to chill the cylinder walls and piston before introducing the actual air to be compressed into the same cylinder.

I think this could explain just about everything. Why the same cylinder does double duty. Why the piston is unusually thin (as pistons go), so the cold produced on one side (top) would also chill the other side (bottom). Why the different types of valves are used instead of all regular check valves.

Why expand and cool such a small amount of air in the cylinder and then just expel it adding a strain on the engine to no apparent purpose: It serves the purpose of pre-chilling the cylinder before doing the actual compression of a much larger volume of air in the same cylinder.

As long as the air was substantially colder than ambient. (The air already in the tank would be warming up to ambient) I think the idea that the "equalizer" served as a kind of "Thermal Pump" would still be valid.

Very cold dense air enters the equalizer through the first check valve. Once between the two valves in the equalizer it begins to warm up and build up pressure forcing itself through the second check valve and into the tank at higher pressure.

So the compression would be a two stage process. First cooling by Joule-Thompson expansion or throttling to cool the piston and cylinder. Second, introducing air into the same cylinder for compression after the cylinder has already been pre-cooled by stage 1.

The small amount of air used for expansion and cooling, once it has done its job of pre-cooling the cylinder, is then largely incidental and is just expelled into the pipes along with the rest of the compressed air.

I'm intentionally neglecting the cooling due to the water circulating around the compression cylinders to avoid confusions, but this would provide an initially cool environment more or less insulating the cylinders from the surrounding ambient heat to help make the cooling by expansion most effective.

OK, I'm wondering if anyone here is good at calculating or figuring out mathematically the whole "ideal gas law" Pv=nrt thing, because I'm not, but I know there are formulas for figuring this sort of thing out.

The air being drawn in by the engine through the valve is initially plain old fresh air at ambient temperature and atmospheric pressure.

There are three possible cooling effects going on.

The valve, depending on how strong the spring is, restricts the amount of air that can be admitted in a given time.

Say the cylinder holds 1 liter (normally by volume). But less than 1 liter of air gets through the valve. Say 1/2 liter or "normal" atmospheric air at 60 degrees F.

So the 1/2 liter is mechanically expanded to twice its volume.

At the same time the air is entering an environment that is, lets say 20 degrees cooler than ambient (the cylinders are water cooled) So there is an inital drop in temperature due to heat being drawn off into the water jacket. At the same time the 1/2 liter of air that gets past the valve is expanded to twice its initial volume.

There is also Joule Thompson "Throttling" as an additional source of cooling but by itself, without a change in volume and environmental temperature is, I think, rather negligible.

Lets just say X amount of gas at 60 degrees Fahrenheit is mechanically expanded in a cylinder to twice the volume.

In other words. If the valve were fully open then 1 full liter of gas would be drawn in by the piston. But the valve is held closed by a strong spring (apparently) so only 1/2 that much air gets into the cylinder but it is mechanically forced to expand to the full 1 liter that the cylinder can hold. It is as=if any amount of air was expanded to twice its volume. (could actually be 1 and 1/2 its volume or twice or three times its volume depending on how tightly closed the valve is.)

This by itself should be fairly easy to calculate with the standard "Ideal Gas Law" formulas. Right ?

So anyway, I've been doing some figuring using some of the Online Calculators available just plugging in values such as might be suggested by the above ramblings - but I am coming up with temperatures that are like hundreds of degrees below zero. I'm wondering if this is realistic or if I'm just not using the calculator right.

Maybe someone knowledgeable in this area can help.

I think most of the relevant values are known or could be approximated.

How much air the cylinders could normally hold, average ambient temperature, etc. This should basically plug right in to standard formulas like pv=nrt.

We could get a rough idea how much cooling might be possible by mechanical expansion alone by 1 stroke of the piston and go from there.

So far it's looking to me like the temperature drop due to mechanical expansion alone could be quite extreme but I'm no expert.

Tom; I have a copy of Audels E&M guide2 book, printed in 1921. Look up Uni-flow engines by Johann Stumpf of Berlin Germany. There are charts of working pressures , althoe these are steam related-  this engine was used as a compressed air unit in mineing operations.

OK.

Well, I've come up with some rough figures about what might be possible in regard to cooling due to forced expansion alone. This does not factor in possible additional cooling by Joule Thompson throttling through a valve or possible additional cooling due to the water jacket reducing the temperature of the cylinder - just expansion.

I wasn't really able to get anywhere with pv=nrt, though it is applicable, the calculations involved are way beyond me, but I found some information relating to the expansion of air due to pressure drop from elevation. This is, it seems to me real world data relating to Air, which is not an "Ideal Gas" exactly anyway.

Using various online sources / calculators / charts etc. I've come to the conclusion that for Air, there would be an approximate 10 degree F drop in temperature for every loss of 1 psi due to expansion (or pressure reduction).

Starting at roughly 14.5 psi at sea level, I'm assuming that expanding that to twice the volume would result in cutting the pressure in half to about 7 psi.

So expanding air to twice its volume would result in a drop in temperature of about 7 X 10 or 70 degrees F.

In other words, if the cylinder can hold 1 pint of air, but due to the strong spring holding the valve closed only about half that amount can get through, the 1/2 pint that gets through would expand to twice its volume to fill the cylinder. That is with what I'll call a medium strong spring.

So starting at 60 degrees Fahrenheit ambient air at 1 atm expanded 2 times the resulting temperature would be about -10 Fahrenheit. 10 below zero.

I'm not arriving at any of this from pv=nrt directly, though some of the sources used it. Rather this is based on pressure changes due to elevation in the atmosphere.

As you climb a mountain the pressure drops. About .5 psi per 1000 ft of elevation. (or 1psi per 2000 ft) and according to the sources, a corresponding temperature drop of about 5 F per 1000 ft.

Primary source: http://hwstock.org/adiabat.htm (http://hwstock.org/adiabat.htm)

also: http://www.unitarium.com/pressure (http://www.unitarium.com/pressure) and others.

Am I correct in assuming that doubling the volume of a fixed amount of air would halve the pressure ? Seems to follow from basic logic...

I'm also assuming that pressure and temperature drop due to elevation would correspond to temperature and pressure drop due to mechanical expansion, which may be wrong but I have little else to go by at this point. Again, seems logical to me.

Anyway, if anyone can come up with a refutation, correction or improvement in regard to these basic conclusions or rough estimates have at it. I'm fairly satisfied that this is relatively accurate, but I'm going about it in a very round about and indirect way.

Basically It looks like to me at this point that there could be a temperature drop from maybe 20 degrees Fahrenheit using a relatively weak spring to possibly as much as 120 degrees for a very strong spring.

In other words, it might not be unreasonable to expect cooling down to as much as - 50 F in the cylinder if a very strong spring were used which severely restricted air intake as the piston "pulled a vacuum".

In such a case the water jacket would only reduce HEATING by the surrounding ambient. That is, the water jacket might be dispensed with as it could be no colder than 32 F (the water would freeze lower than that) which is HOT compared to -50 F. But using the water jacket would improve efficiency but might not have been necessary in a small model engine such as was supposed to have been taken to the patent office.

"Throttling" or Joule Thompson effect cooling might contribute to some additional temperature reduction. With some gasses this effect (throttling) actually increases the temperature, but atmospheric Air Happens to be a mix of gases which can be cooled by throttling or Joule Thompson effect. This is not due to expansion exactly but as far as I've been able to figure, ACCELERATION as the gas rushes through the valve opening. The heat is converted into Kinetic Energy. The air molecules apparently themselves absorbing the heat to pick up energy for acceleration. A rather strange notion but that's more or less how the sources on the topic read or explain it.

If this whole compression by cooling theory is in the ballpark, than I think that also explains why the Power Pistons driving the engine don't have any water jacket for cooling in the patent illustrations.

The "compressor" cylinders do the cooling. Though not really compressors, just combination coolers and pumps working at atmospheric pressure. The actual compressor is the "equalizer" which becomes a kind of hydraulic thermal pump or compressor inside the tank.

The compression or pressurization to 200 psi to drive the power pistons takes place after the supercooled air passes the equalizer and gets into the tank due to the re-absorption of ambient heat. This re-absorption of heat continues on into the power pistons. The hotter the power pistons the more heat the gas can absorb. The more heat it absorbs, the more it expands to drive the engine, Heat due to friction would increase the power of the engine - So having a water cooling jacket around the power pistons would defeat the purpose. They are allowed to remain hot, so... no water jacket. Instead there are electric heaters!

At first I thought this whole idea was only a wild and very remote and unlikely possibility and probably wrong, but the more I look at this and think about it, I'm starting to actually take it seriously. The pieces of the puzzle seem to be falling into place.

Heres some PDF files to look over. The 1986 & Young file is interesting. These are all on vaccume pump technoligys. I guess your starting to see what i stumbled across when doing some test on this type engine. Still in the works

Quote from: Motorcoach1 on January 27, 2013, 12:26:37 PM
Heres some PDF files to look over. The 1986 & Young file is interesting. These are all on vaccume pump technoligys. I guess your starting to see what i stumbled across when doing some test on this type engine. Still in the works

Thanks, it will take me a while to peruse.

Anyway, I've been thinking about a few things that I think might be important as far as design considerations, though this is mostly just my own imaginings or visualizations based on nothing.

I've been trying to figure out, regarding the large valve in the top cylinder section, how the possible cold produced by "pulling a vacuum" could be maintained.

Normally, I would think that it wouldn't. The reason being that: OK, so the piston pulls a vacuum and expands some air and the air gets cold temporarily. But when the piston goes back up to push the air out through the check valve to the line leading to the tank won't the air be re-compressed and therefore heat back up again ? It doesn't seem like there is anything to be gained by this throttling valve. If that is, in fact what it is supposed to be.

So mulling this over and imagining and visualizing this scenario.... The air is pulled in, expanded, cooled, then compressed again... Hmmm...

Then I think I hit upon the answer and discovered Maxwell's Daemon lurking in this process.

The engine was probably Cast Iron given the era. Cast Iron is a metal that can absorb and hold a tremendous amount of heat, relative to air anyway. You have a cold cast iron engine cooled with water.

Now draw a vacuum in the cylinder admitting some air. The air is not uniform in temperature on a molecular level. Air is a mix of gases. There are some high energy speedy (hot) molecules zipping around and some slow low energy (cold) molecules all pack together and bumping into one another and exchanging heat all the time. Temperature of the air is the AVERAGE kinetic energy. So there are hot and cold molecules mixed together.

When the air is drawn into the cylinder and expanded, also accelerated, While expanded in the cylinder there is more SPACE between the molecules. The space allows more freedom of movement. The molecules don't bump into each other so much or so often and move around in the cylinder more independently without colliding and exchanging heat.

So the slow cold molecules kind of meander around without bumping into anything while the HOT molecules zip around and ricochet off the cylinder walls. In colliding with the cold water chilled cast iron the high energy hot molecules transfer heat/energy to the metal and join the cold molecules. Very quickly, the heat is gone, it melts away into the metal of the cylinder to eventually be carried off through the water jacket. The AVERAGE Kinetic Energy of the gas has been reduced considerably and permanently. When it is pushed back up and out of the cylinder it doesn't get hot again. It stays cold.

There is another advantage to this.

With the arrangement Neal has for this "compressor" with the piston doing double duty...

I said earlier that it takes work or puts a load on the engine to pull a vacuum.

But there is a flip-side in that after the gas has been expanded and cooled, the vacuum will PULL THE PISTON!

If anything, since the gas has cooled by expansion and heat loss to the cylinder walls, as well as throttling, the vacuum will INCREASE, or at least it won't decrease. It should pull the piston back with just about as much force as the piston exerted to create the vacuum in the first place.

With many such compressor pistons, while one is pulling a vacuum another will be getting pulled by a vacuum, possibly with even a slightly greater force! due to the gas having cooled it will contract more potentially creating a stronger vacuum.

In other words, this compressor should be practically FREEWHEELING. No wonder that only two power pistons are needed to drive what, 14 double acting compressor pistons! That's 28 compression strokes for each rotation of the crankshaft. Seems like this would be impossible. How could just two power pistons drive so many compressors? Why not!?!?!? The compressor is practically freewheeling. Practically every bit of work it does "pulling a vacuum" and cooling the air it gets right back on each return stroke as the vacuum pulls the piston back up.

I'm really beginning to see how this engine might actually work. How it could compress more air than it uses. I'm really amazed. It seems to me this Bob Neal must have been some kind of practical Genius to have figured this stuff out and to have actually made it work.

Hi Tom,
this discussion gets more and more intersting. I have to reread this tomorrow. Here it is 23:00.
My question is: Where gets this engine his power? As I have understood you mean that it gets it not from compression but from pulling a vacuum which cools the air which pulls the energy from the air (by expanding this cooled air)
What makes me thinking: It also takes power to get a vacuum. The old greeks said: Nature hates vacuum.

Quote from: AlanA on January 27, 2013, 05:14:20 PM
Hi Tom,
this discussion gets more and more intersting. I have to reread this tomorrow. Here it is 23:00.
My question is: Where gets this engine his power? As I have understood you mean that it gets it not from compression but from pulling a vacuum which cools the air which pulls the energy from the air (by expanding this cooled air)
What makes me thinking: It also takes power to get a vacuum. The old greeks said: Nature hates vacuum.

The basis of the theory I'm working on, due primarily to the topic starter drawing attention to something unusual about the valves... I'm not really sure that what he was talking about was what I found, but anyway...

This is just my theory. I am becoming more and more convinced its right but that remains to be seen. But anyway:

Air can be reduced in volume in two ways. Either forcefully compressing the air or by cooling the air. Both will accomplish more or less the same thing.

Pulling a vacuum to expand the air temporarily is not the source of energy to run the engine. That is just one of the apparent methods of cooling used.

By cooling the air it contracts on its own without needing to be forcefully compressed.

What looks like an advantage of using this method is that much, if not all of the energy used to cool the air is gotten back immediately because after the piston creates the vacuum and the air is cooled the vacuum gets stronger due to the cooling. Having gotten colder the air contracts and pulls the piston back. That just recoups some of the power, kind of like regenerative breaking I'd say, but that isn't really what is driving the compressor.

After the air is cooled to a very low temperature, it is sent to a special valve. The valve is like a hydraulic jack, the way it looks to me. A hydraulic Jack works the same way. A hydraulic Jack is also basically just two check valves.

In a jack, between the two check valves you have a plunger that goes up and down to draw the fluid in one check valve and then force it out the other. With the valve in the Neal Engine's Tank, I think that the air itself acts as the "plunger" to pump itself through the check valves by thermal expansion from ambient heat. The cold air goes past the first check valve. Between the valves it heats up and expands forcing itself through the second valve.

The real power to drive the engine is derived from ambient heat.

Once the cold air is in the tank, the tank is surrounded by ambient heat which causes the air to re-expand to the volume it had before it was cooled. So now once in the tank and re-heated the air builds up pressure. It is the pressure created by heating the air back up with ambient heat that drives the engine.

It should be kept in mind that the engine driving the compressor is different from the compressor itself, though the two are combined in one unit on the same crankshaft. There are two power pistons driving 14 cooling units or "compressor" pistons.

The engine is driven by air pressure.

The engine then drives the "compressor"  - really a set of coolers as it looks to me. The "compressor" does the work of cooling the air so it can be easily sent into the tank.

The real source of energy powering it all though is solar energy stored in the atmosphere as ambient heat which heats the air back up and creates the pressure to run the engine.

It looks like a beautiful arrangement, but as I say, there is nothing explicitly stated in the patent to confirm this. As of yet it is just a theory. It's just one possible explanation of how the engine might have worked. I'm becoming rather convinced it might be right though.

Part of the cooling is accomplished by cold water circulating in the water jacket.

I'm not sure how necessary the water cooling is. The patent doesn't say much of anything or even show if the water is cooled by a radiator or what.

If there is an unlimited source of cold water, like a well or a stream or spring then the engine might not have been able to run without this source of "Free" cooling.

However, he is supposed to have gotten a patent by demonstrating a smaller version of the engine, wetting it on the patent examiners desk and running it. I doubt there was a well or stream or source of cold water such as that at the patent office, who knows ?

I'm not sure the small model needed water cooling.

Just a correction regarding a typo. My editing time ran out.

"Wetting it in the examiners desk" Was supposed to be Setting it on the examiners desk.

He didn't Wet or put water on the engine, its just that W is right over S on the keyboard. Sorry. That that was a typo may not have been obvious due to the context.

By the way, is someone REALLY going to try to build one of these engines ?

If so I'd be interested in getting involved in some way if possible.

Regarding comments on pv=nRT,
Sloane's Liquid Air text includes some clear explanations of gas behavior.  I took time to condense his writings from chapter 1 and 3, attached here, because I was thoroughly impressed with his words.  The ideal gas law tells us that the pressure, volume, temperature, and number of gas molecules are all intertwined together.  With air, if gas molecules and temp are held constant, then the pressure and volume are related by p*v^1.4, not by p*v. 

Tripler used this method when he allowed high pressure air to expand through a nozzle, to the atmosphere.  The atmosphere is a fixed sea of 14.7 psi and an equivalent volume, or density of gas molecules. So when Tripler's air passes through the nozzle, it must conform to the p and v of the outside atmosphere.  The pressure might drop to 14.7, but because of the v^1.4, the resulting volume will still be too small of a volume, ie, still too dense.  Since the outside atmosphere is un-moveable, the expanding gas will be forced to steal energy from the T of the ideal gas law, which results in a temperature drop of the gas.  I am just repeating what is already stated in the attachments.

Sloane in chapter 1 explains clearly about energy and force, and work.  All his explanations use visual examples, but in each, he is implying gas behavior, so be sure to think about the gas applications when reading his examples.  These are the most basic building blocks to be used with gas manipulations.  This is where the overunity effects will be found, in my opinion.  It is amazing that this text was written 100 years ago!

The Neal compressor pistons include a large amount of volume that is being pumped.  I do not see how the external pipe walls can transfer enough heat, fast enough, to sufficiently expand a cool gas in the equalizer since this type of heat transfer is a relatively slow process.
If the compressor cylinder pulls a partial vacuum, then when the upper valve opens, it seems the outside air would rush in quickly and equalize the pressure in that cylinder before the valve closes.  The discussion about gas particles moving fast and slow inside the cylinder, I do not think is valid, since any gas, even at low temperatures, contains fast moving gas particles, otherwise it would be a liquid.
What I do think, is that in an earlier post you were correct in thinking that possibly the engine cylinder exhausts could be connected to the upper compressor cylinder valves.  To me, this makes sense.  The lower inlet valves are still inletting from the atmosphere, for make-up air.  The uppers would be able to salvage some of the temp cooling for re-use in the machine.
I think the assertions in your earlier posts are physically correct, but the question is whether those effects will produce over-unity.  Need to develop an energy audit to identify the energy in and out, of course, easier said than done!

Very interesting read fellas. Thank you.
Sry for the hyjack. Moby.

This is a very interesting discussion. I followed them in the last weeks. There is also an intersting discussion at http://aircaraccess.proboards.com/index.cgi?board=general. But they also fishing in troubled waters.

But I think it is very hard to find out what Bob Neal invented. It is like fishing in troubled waters. I think air engines have to be understood as an heat engine. It is the engine which might be generated between hot air (expansion) and cold air (contraction). In the past days I was thinking about the vortex tube. I am not sure if this part can held us solving our problem. It is well known that this hilsch-ranque bute seperates a compressed airstream in a hot and in a cold part (Ok is takes a lot of energy to compress air - we all know). But BOTH streams could be useful. Cold air to heat air and cold air to compress air. But don't forget the heat the compressor generates itself at work. Luther once said. All the air you need to compress air get lost by heat (or something like that).

In my opinion, I am not in a big hurry to construct a Bob Neal look-alike machine.  There were several air power builders during his time period, but concrete information is sparce.  So, I see Bob's patent drawings as a view into this secretive subject from that era.  I believe that all the air car builders were utilizing the save physics process, and since pv=nRT, the air liquifiers are also using a similar process, (at the basic physics level), to achieve overunity effects.  Overunity meaning to extract useful energy from the ambient energy of the atmosphere.

Possibly we could discuss overunity, and begin from the most basic level.  Take heat for example. 
1.  Heat can travel due to thermal radiation, which is an infrared wave, in physics it is called "black body radiation".  This is how those motion sensor lights you can buy for $9.99 work.  This is a fast process, but I think the amount of energy transferred will be quite low, unless you have access to the sun. 
2.  Heat can also travel by conduction/convection which would be the molecules of a solid or of a gas bumping into each other and sharing their respective energy content.  With a gas, this convection will cause the heat energy to flow through the gas at a defined rate determined by the amount of gas molecule collisions.  Heat applied to a pipe with gas inside would also be this process.  This process is able to move large amounts of heat energy, but is still a relatively slow process. 
3.  Finally, we have the molecular heat energy, (maybe someone can find a better term for this?).  This is the internal heat of the gas which can be changed by expansion, expansion against a load, and by compression.  This method of heat transfer can move large amounts of energy, AND it can occur very fast.  I think that #3 is where the overunity, or ambient energy extraction will occur.

Could someone out there comment on these three items?  Is this list complete, is it accurate?

Now look at pressure.  With a gas, there is a unique process where it is possible to create adiabatic compression and expansion by using a pressure wave.  For practical purposes, a pressure wave can be considered non-dissipative, (much more so than other methods).  This is an available tool to use with gas manipulations.  A pressure wave can co-exist, or be superimposed upon, a steady flow of gas, with little or no interaction between the two effects.

As mentioned earlier, the vortex is another physics process that is available.  This is similar to a pressure wave, but is turned back on itself.

In order to extract energy from the atmosphere, our machine needs a connection to that atmosphere.  The machine walls will conduct heat as in #2 above, but that is a slow process.  For the fast molecular heat energy transfer we need to access the atmosphere gas molecules directly.  Trippler style air liquifiers access the atmosphere at their machine outlet, where is located the expansion nozzle.  Bob Neal has two locations with access to the atmosphere molecules, his inlet valves, and his engine cylinder outlets.

Bob Neal has several checkvalves throughout his machine.  Are checkvalves used for heat transfer?  I say no.  Checkvalves are used with pressure differences.  If we create a pressure difference at Neal's inlet valves, and then open those valves, then the atmosphere will rush in.  The greater is the pressure difference, then the faster will the atmosphere gas molecules rush in.  If we look at Neal's machine inlet from the pressure point of view, then the question becomes:  What is the most energy efficient method to develop a pressure differential at the machine inlet?

Are there other basic physics processes that are not listed here?  Discussing heat or pressure is just choosing a convenient point of view, since in the end, p,v and T are all intertwined together, and all will need to be accounted for.

Comments or further discussion would be appreciated.

The main things that strike me as important to keep in mind are 1. Neal's patent claims that the so-called "compressor" doesn't actually compress any air but works at atmospheric pressure. Low pressure air at about 15 psi (1 atmosphere) is pumped to the tank. The tank pressure is much higher, if I remember right about 100 psi.

The second thing that strikes me as important is the passing reference about the heaters used to bring the air (from the tank) up to or just above freezing just before, or as it enters the power cylinders.

I have to assume the tank is sitting in normal ambient. Probably somewhere between 50 to 80 F.

So you have warm ambient air going into the compressor ending up as very cold air in the tank needing to be heated back up for power production.

The implication being that somehow the process of "compression" is cooling the air down to well below freezing. Water cooling alone could not do this. The only possible mechanism I see for accomplishing such extreme cooling is the big valve at top of the cylinder. The incoming ambient air being "throttled" resulting in Joule-Thompson effect cooling.

This type of cooling is used industrially in liquifying gases, refrigeration, air conditioning etc.

"The throttling process is of the highest technical importance. It is at the heart of thermal machines such as refrigerators, air conditioners, heat pumps, and liquefiers." - from M.J. Moran and H.N. Shapiro "Fundamentals of Engineering Thermodynamics" 5th Edition (2006) John Wiley & Sons, Inc.

http://en.wikipedia.org/wiki/Joule–Thomson_effect (http://en.wikipedia.org/wiki/Joule%E2%80%93Thomson_effect)

If that is the mechanism used in the Neal engine, to me this also provides an explanation for how the "equalizer" works, as a kind of thermal pneumatic PUMP.

If the air were "throttled" so as to reach an extremely cold temperature and delivered to the equalizer - still very cold, if not actually liquified, then by comparison the equalizer would be EXTREMELY HOT at ambient temperature. I don't see that the heat transfer under such circumstances, by conduction, would be "too slow" to produce a rapid thermal pumping effect to drive the air into the tank. Almost any pump of any kind you might care to look at other than a rotary or screw type pump consists primarily of two check valves. If the equalizer is a thermal pump activated by temperature change then it needs no other mechanism.

The cold air or liquid air having entered the equalizer warms up and expands so its pressure rises rapidly from 15psi to above 100psi and it is forced into the tank. As it rushes out into the tank it leaves a vacuum which draws more cold air into the equalizer.

To me this fully explains the working mechanism behind the engine 100%.

If it is wrong, I can't really for the life of me see any other possible solution.

I think this could be tested by constructing just one such "compressor" cylinder with such a "throttling valve" and attach the outlet to a tank (with an equalizer) and see what happens.

The one cylinder would not have to be a full working engine. The piston could just be driven by a motor on a bench. The valve could be made adjustable. Slight variations in the spring tension could make a tremendous difference as far as cooling effect.

By such an approach it would be possible, I think, to test these key components and see how they work together at relatively little expense.

I no longer believe that the cooling has anything to do with return air from the power pistons. This made sense to me at one point but there really doesn't seem to be any indication that the air is recycled in such a way in the patent and in the interview with Neal's son he states that the air from the power pistons was simply exhausted back to atmosphere. That his father never found any way to recycle or reuse this air at all. It seems unlikely to me that his son was mistaken about this.

I wouldn't want to underestimate the possible cooling effect of the "throttling". From everything I've read about it it seems to be the key to getting gases down to extremely cold temperatures, potentially even down to the point where the result is actual liquefaction of the gas.

I suppose I could be wrong but this is the only explanation that appears to me to solve all the mysteries and fully explain the various reasons for and functions of all the elements in this engine.

There would certainly be some kind of RHYTHM or "frequency" or "pulsation" to the "pumping action" of the equalizer, as with any such pump, but I think such harmonic "waves" would originate at the equalizer itself. It would fall into some natural rhythm, but this would not be dependent on the pistons in the compressor or their arrangement or number or anything of that sort. It would be purely a result of the thermal changes going on within the equalizer itself. So I believe that a test using just one cylinder for "compression" or cooling and one equalizer would work as well as anything else.

Quote from: Joe1 on January 29, 2013, 10:27:32 PM
...
If the compressor cylinder pulls a partial vacuum, then when the upper valve opens, it seems the outside air would rush in quickly and equalize the pressure in that cylinder before the valve closes.  The discussion about gas particles moving fast and slow inside the cylinder, I do not think is valid, since any gas, even at low temperatures, contains fast moving gas particles, otherwise it would be a liquid.
...

It may be a moot point but I don't agree with the above statement: "the outside air would rush in quickly and equalize the pressure in that cylinder".

This disregards the extra pressure exerted by the valve spring which I think, in this case could be considerable.

In other words, there would have to be a rather strong vacuum before the valve would even open. When the valve did open it would not rush in freely and immediately equalize but would be "throttled", that is, severely restricted. I don't think there would be any equalization of pressure on the down stroke. There wouldn't be any equalization of pressure, I don't think, until the piston was rather far along on the return (upward) stroke. Finally, towards the top of the upward stroke the pressure in the cylinder would climb above the 15 psi atmospheric pressure and the check valve would open allowing the air to escape into the pipe leading to the tank.

At any rate, I have been discussing this point about the apparent "throttling valve" on one of the science forums to get some outside perspective on this Joule-Thompson throttling valve idea in relation to this engine that some here might find interesting.

One of the points raised recently there is that the Joule-Thompson effect could only account for a few degrees temperature drop.

IMO, this is not necessarily true as these sort of calculations are based on a one time event. That is, the release of some air through a valve or other throttling mechanism from one chamber into another. The temperature drop from Joule-Thompson Effect in such a circumstance is relatively insignificant. Perhaps only a few degrees.

My counter argument to that is that the situation in a running engine is quite different. For example, I cited this Wiki Article: http://en.wikipedia.org/wiki/Carburetor_icing (http://en.wikipedia.org/wiki/Carburetor_icing)

The pressure drop in an automotive carburetor at the throttle is relatively slight, I should think, compared with the potential pressure drop intentionally produced with a throttling valve as in the Neal engine, yet with continuous operation of the engine, the effect is, apparently cumulative, the result being, in a car engine, the icing up of the entire throttle body with the potential for causing damage to the carburetor or possibly a run away engine due to the throttle becoming frozen in position. "The inlet manifold and parts of the carburetor often have warm water from the cooling system or exhaust gas circulating through them to combat this problem."

http://www.scienceforums.net/topic/72398-help-needed-for-pvnrt-calculation/?p=731866 (http://www.scienceforums.net/topic/72398-help-needed-for-pvnrt-calculation/?p=731866)

I don't really know at what RPM the Neal engine was supposed to operate, but supposing that there was a cooling effect of just 1 degree with the first down-stroke of the piston. This would presumably result in some cooling of the valve itself and the surrounding housing, the cylinder as well as the top of the piston etc. possibly to only an imperceptible degree. Very slight cooling. But then this is repeated over and over again. The cylinder might grow a degree colder with the second stroke and a degree colder with the third.

If the compressor were operating at just 300 RPM which is very slow compared with most engines (that might operate at several thousand RPM), The CUMULATIVE temperature drop could be quite significant in just the first minute of operation.

The reason I bring the reference to carburetor icing into the discussion is that this seems very similar to what might be expected with the Neal device as it involves a pressure drop in ordinary air through a throttling device from atmospheric pressure to some lower pressure in a continuously operating engine rather than in a more controlled "scientific" environment where air is simply throttled between two chambers.

What might seem like a relatively insignificant drop in temperature under carefully controlled conditions, could in fact, IMO, be highly significant in a situation where the effect is continuously repeated and cumulative.

Thanks so much for the thoughtful comments.  I will study your insight and try to contribute to your theory.

Hello Tom Booth,
I promised to find something to support your heat engine theory.  It has been 6 months, but here it is.  Hopefully this thread is still working.  Have you ever seen these three patents?  They all promise overunity performance. Warning, these are looooong patents, but there is much information contained within.  Took me a while to find them.

8268030 Abramov 2012
I like this one. He references Bernoulli, Coanda, De Laval nozzle, Ranque-Hilsch vortex tube. You must read closely, he is not spoon feeding, but the data is there. Smart guy.
column 21, lines 36-43
col 23, lines 7-12

7775063 Thompson 2010
column 23, lines 9-25

4624109 Minovitch 1986
This guy talks like a snake oil salesman, but he was awarded the patent.
col 1 lines 12-53
col 12 lines 26-44
col 20 lines 42-47

These line references are just to get you interested. Reading these will be a long journey, so much information, amazing. If a reader could learn these three, It seems a working model of an overunity heat engine would be possible.
Joe1

Hello Joe1,

thanks for your advices to this three patents.
You seems to be very optimistic. What make you so shure that all these inventions really work? I am not so optimistic. You could find tons of patent files with odd claims. Do you know some of this inventors? Are there some prototypes?

Alana

Just sharing the patents, have not had time yet to thoroughly analyze.  Two are very recent.  I think it is worth the time to try to analyze these, and there is certainly much information contained to work with.  I wonder about the fellow from the earlier patent.  This information is similar to the Trippler info.