Cadman’s Hydrostatic Displacement Engine

[Cadman]

Now that I've had time to really look at it, I think Graham's design is more elegant than my own.

Way to go Graham!

Regards
cadman

[Grumage]

Graham,

(Floor posted while I was writing this. I'll let him explain but he's pointing out basic pressure multiplication or division with one piston having unequal surface area on each of it's faces. Also difference in motions between unequal piston diameters.)
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My analysis.
Double check my figures, but I think they are correct.

Assume a working head of 2 meters
pressure at bottom = 2.844 psi dropping to 2.627 psi after up-stroke

The concertina is made to have an internal surface area of 6 square inches
2.764" diameter = 6 sq. in.

The fixed displacement piston ... has a diameter of 1/2"
1/2" dia = 0.196 sq. in.

The displacement cylinder ... diameter is much smaller perhaps 3/4"
3/4" dia = 0.441 sq. in

Weight of liquid above concertina in the displacement cylinder minus the displacement piston volume
1.923 lb.

Up-force from concertina with transfer valve closed
15.765 lbs at the top of the stroke

Up-force from concertina with transfer valve open
0 lbs

My conclusion:
The inlet valve in the base is not needed.
The transfer valve is the one to be opened or closed at the end of the strokes.
If the transfer valve is the one shifted, then this will work, provided the total weight of the concertina piston plus the displacement cylinder plus the weight of liquid above the concertina is less than the up-force from the concertina (15.765 lbs).
With the transfer valve opened the liquid will seek the level of the head through the displacement cylinder with no upward force exerted on the piston. The concertina / displacement cylinder assembly is free to sink to the bottom of the stroke.
With the transfer valve closed the liquid is separated into two volumes and the head pressure will exert influence on the concertina piston bottom surface and provide 15+ lbs of lift. The liquid above the concertina piston becomes a static weight. If the static weight (liquid plus mechanical weight) is less than the lift force the concertina piston + displacement cylinder will rise.

The issue to contend with is to have a head reservoir of sufficient volume to in order to minimize the loss of head height while filling the concertina since it's volume is much greater than the displaced volume.

Cheers
Cadman

Hi Guys.

It's a pity we can't converse by other means, I hate typing!

I don't think we can dispense with the bottom admission valve as we want the concertina and displacement cylinder to collapse back to rest for the next cycle. However I have realised there might be a flaw in my idea. Upon opening the transfer valve ( top of stroke ) the bias weight along with the weight of the displacement cylinder should transfer the water into the smaller diameter cylinder above ( the collapse ) We close the transfer valve and open the admission valve. The concertina rises along with the displacement cylinder the water is now having to pass the sides of the displacer piston and through the cup washer. We open the transfer valve again, is this where things get stuck? Do we need to allow air in to get the concertina assembly to collapse for the reset? Hmmm....

Cheers Graham.

[Cadman]

Hi Guys.

It's a pity we can't converse by other means, I hate typing!

I don't think we can dispense with the bottom admission valve as we want the concertina and displacement cylinder to collapse back to rest for the next cycle. However I have realised there might be a flaw in my idea. Upon opening the transfer valve ( top of stroke ) the bias weight along with the weight of the displacement cylinder should transfer the water into the smaller diameter cylinder above ( the collapse ) We close the transfer valve and open the admission valve. The concertina rises along with the displacement cylinder the water is now having to pass the sides of the displacer piston and through the cup washer. We open the transfer valve again, is this where things get stuck? Do we need to allow air in to get the concertina assembly to collapse for the reset? Hmmm....

Cheers Graham.

Yeah, I wish we could converse too. It would make things a lot easier.

Think about it without the admission valve.

Picture it like Floor did with the U tube. With the transfer valve open there is an unblocked path on the left from the top of the reservoir to the bottom of the concertina, through the concertina, and back up to the reservoir. The concertina is just like a dense restrictor orifice at this time sitting at the bottom of the right half of the U tube.

Now close the transfer valve and the fluid above the concertina is separated from the fluid in the left half of the U tube. Being lighter than the left fluid column the concertina, which now has a solid piston top, along with the displacement cylinder plus the smaller amount of fluid above it will rise as the two halves in the U tube seek a balance.

Open the transfer valve now that the assembly is elevated and the concertina reverts to a restrictor and being more dense and heavier than the liquid it will sink to the bottom. Your own video proved that.

Cheers
Cadman 

[Floor]

I like Grumage's bellows usage.  Maybe bellows type boots (used to cover
front axles on trucks / autos) could be adapted to this purpose.

[broli]

@Floor since you grasp Grumage latest concept could you draw a cyclic diagram of that concept? I think many would struggle with all the textual descriptions here. I can even do an 3d animation if needed but need to understand it better first.