Hydrosonic Pump

[rapttor]

I've recently built a replication of Grigg's pump, I have to say.. I turned it out in maybe 3hrs on a small scale for proof of concept to see just how well it works. It sure does, only my haste came back to bite me in the ass, when I realized one of the big issues with this pump is sealing the pump shaft. I used a piece of 6061 aluminum for the rotor, pressed in a 5/16 steel shaft, used an old pair of rollerblade bearings, the housing is a piece of 2" chrome steel exhaust piping, with 3/8" thick end plates. I'll post up pics of it shortly. I have a larger unit in the works already which will have a 5.25" rotor inside a section of cast iron pipe.
When I spun up my test model, there's a certain rpm that the cavitation starts to really take off. I didn't do any actual measurements of temps, but with my fingers on the outside of the main casing (tube) it went from room temp to untouchable in a matter of maybe 15 to 20 seconds!! suprised the hell out of me.

Anyone have ideas on how to seal the shaft? Teflon? pressure rings? I'm all ears.
-art

[mikestocks2006]

I've recently built a replication of Grigg's pump, I have to say.. I turned it out in maybe 3hrs on a small scale for proof of concept to see just how well it works. It sure does, only my haste came back to bite me in the ass, when I realized one of the big issues with this pump is sealing the pump shaft. I used a piece of 6061 aluminum for the rotor, pressed in a 5/16 steel shaft, used an old pair of rollerblade bearings, the housing is a piece of 2" chrome steel exhaust piping, with 3/8" thick end plates. I'll post up pics of it shortly. I have a larger unit in the works already which will have a 5.25" rotor inside a section of cast iron pipe.
When I spun up my test model, there's a certain rpm that the cavitation starts to really take off. I didn't do any actual measurements of temps, but with my fingers on the outside of the main casing (tube) it went from room temp to untouchable in a matter of maybe 15 to 20 seconds!! suprised the hell out of me.

Anyone have ideas on how to seal the shaft? Teflon? pressure rings? I'm all ears.
-art

Hi raptor, nice work!
If you post some pics or cross section schematics it might be easier.
Without knowing your exact configuration at the bearing areas, rotational speeds, pressures and temps involved, I'll try some general input:
a. you can try O-rings around the shaft, use a spring and a washer to improve the seal. O-ring against the end plate, washer against the O-ring, one spring-end against the washer and other spring-end against the rotor. I/4" ID O-ring and 5/16" ID washer (they are usually oversized on the ID) and a 3/8 ID spring should do the job.

b. If you have access to any old hydraulic cylinders, they have some nice V-lip seals radialy spring loaded on the shafts and also on the pistons you might use if the dimensions match.

c. materials, would depend on speeds pressure and temps. I'd start with some Silicon O-rings from the local hardware store if you have access to one. Or try depending on Dia the washers used for the hot side water faucets etc.

d. high pressure sealed bearings would to the job too off the self, but they can be expensive, for proof of concept.

e. the easier and simplest way may be to have the shaft to end plates as a simple -slip fit- smooth/polish the surfaces and use option a. above.

Note, the second bearing area can be completely covered. so you'd only need to seal the drive side. (Like an end bell cap, pipe cap, over the free shaft side etc.)

I hope this helps

[dynamicdj101]

Hi !!!  I'm new here. You could use a seal from a car or big engine water pump. There are also pumps that use magnets on each side of the pump casing so there isn't a shaft to seal.

[rapttor]

@ Mikestock

Sure does help, I've wrapped my mind around this issue several times, so what you are explaining... makes perfect sense to me.
I'm on call this week for work(luckyme) and got called out to work on a Cell site at 2a.m. & I didn't get in until 5:30am this morning.
I just hoped in the truck and headed, so I didn't get any pictures yet... but I'll toss up a basic diagram so you have a better idea of where I'm coming from.

Here's some info that I know off the top:
RPM's - approx 8K to 15K (smaller the unit, higher the rpm, larger the lower the rpm).
Temps - 250' F to 350' F
Pressures (water inlet pressure) - up to approx 75 lbs
Bearing Surfaces - On the end plates, on the outside faces, bearings will be recessed, flush with the surface. inner hole dia. would match rotor shaft size & have approx .001 - .003 clearance, easier to seal.

I'll draw some simple diagrams so you have a better mental image of where I'm coming from.

Regards,
-art

[Paul-R]

Did not John Worrell Keely have a hydro-vacuo or hydropneumatic device of some sort? Using the energy of water hammer in bad plumbing?
Paul.