Cothran PowerHouse Valve and TP.

[miksatx]

Curious how that valve is supposed to open easier? IMO it will not. Lots of closing forces but I cannot for the life of me see how it would open any easier than any other popped valve.
Walter.....

I own 3 cothran tubes all have powerhouse valves. I know for a fact they open easier than a p rod valve with out pressure against it. If you don't own one you don't have a informed opinion about it.

[rsterne]

Walter, you need to talk to Al (Gippeto).... Here is what he wrote about it, referencing the photo on the Cothran website.... http://www.cothranmachine.com/PowerHouse%20Valve%20from%20October%202013.pdf

Very small hole in the valve stem is a vent...(can just be seen below and to the left of center of the o-ring) stem is partially hollow. Small piece of rod slides inside of valve stem.

Piston assembly on the right is secured to the body by the screw. 

Valve "hat" is hollow...slides over top of piston assembly...uses the urethane seal shown...lower force holding valve closed requires softer material to seal.

The piston area being vented to atmosphere, the net effect is a reduction in surface area for pressure within the valve to push on...resulting in lower opening force.

During the shot cycle, pressure bleeds through the hole in the valve stem, past the rod to the piston assembly and adds a considerable amount of closing force. Once shot cycle is completed, this would then vent back to atmosphere...rod would slow the venting, helping hold the valve closed during early (higher force) hammer bounce events. Rod diameter could be tweaked to adjust fill rate/closing force, but would also effect on the venting end....

I admit that without Al's description of how it operates, I had no clue.... 

Bob

[Monkeydad1969]

Curious how that valve is supposed to open easier? IMO it will not. Lots of closing forces but I cannot for the life of me see how it would open any easier than any other popped valve.
Walter.....

I own 3 cothran tubes all have powerhouse valves. I know for a fact they open easier than a p rod valve with out pressure against it. If you don't own one you don't have a informed opinion about it.

The PowerHouse valve is a GOD among valves ...it is very nice.  Yes it is very easy to crack open.  It does amazing power.

Joe

[YEMX]

I'm still hoping he does one for a Prod!!!

[Monkeydad1969]

I'm still hoping he does one for a Prod!!!

That would be sweet.  Have you asked him yet?  Can you imagine one for a M-Rod?  Can you say .30 M-Rod conversion?

[Voltar1]

The piston inside the stem is a closing force best I can determine.
Respectfully beg to differ with Al on this one.

[Voltar1]

Curious how that valve is supposed to open easier? IMO it will not. Lots of closing forces but I cannot for the life of me see how it would open any easier than any other popped valve.
Walter.....

I own 3 cothran tubes all have powerhouse valves. I know for a fact they open easier than a p rod valve with out pressure against it. If you don't own one you don't have a informed opinion about it.

Held one in my hands fully dissassembled. Made a full sketch of the unit. Does that count for an informed opinion?
What pray tell does no pressure forces have to do with the discussion?

[rsterne]

Piston is bolted to the front of the valve, so the area of the piston (smallest black O-ring) is subtracted from the area of the sealing surface of the poppet seat (somewhere on the white O-ring), since the inside of the "top hat" shaped poppet is vented to atmosphere when the valve is closed.... I've never had one in my hands, but Al's description makes sense to me when I look at the photos.... Since it is a known fact that the valve is MUCH easier to open at a given pressure, perhaps you have another explanation?.... The small rod inside the valve stem works like a "leaky check valve" in combination with the tiny bleed hole in the stem, helping the valve to not open during hammer bounce.... but allowing the inside of the poppet to return to atmospheric pressure before the next shot....

If you have a sketch that shows otherwise, I'd love to see it.... scan it and post it?....

Bob

[Voltar1]

High pressure on piston seal will push on the sleeve closing the valve
On firing the small rod becomes active assisting the popped return to closed.

[rsterne]

High pressure on piston seal will push on the sleeve closing the valve

Sorry, I don't understand.... The piston, carrying the small O-ring, is bolted to the front of the valve and doesn't move, correct?....
The vent hole in the valve stem is inside the exhaust port of the valve, and hence is at port pressure.... high during firing, atmospheric between shots....
The small rod inside the stem rattles around with a small clearance, delaying pressure change immediately after a shot.... to avoid bounce....
After the shot, the inside of the valve stem, and hence inside the poppet sleeve, is at atmospheric pressure.... therefore the closing pressure acts only on the seat area MINUS the piston area....

What did I miss?....

Bob

[Voltar1]

Pressure inside pushes towards low pressure. In this case the piston is stationary and force acts on move able sleeve to push it off the piston. A closing force

[miksatx]

Curious how that valve is supposed to open easier? IMO it will not. Lots of closing forces but I cannot for the life of me see how it would open any easier than any other popped valve.
Walter.....

I own 3 cothran tubes all have powerhouse valves. I know for a fact they open easier than a p rod valve with out pressure against it. If you don't own one you don't have a informed opinion about it.

Held one in my hands fully dissassembled. Made a full sketch of the unit. Does that count for an informed opinion?
What pray tell does no pressure forces have to do with the discussion?

Well maybe ya should have put it together and pushed the valve stem in and out with your thumb. Instead of drawing pictures of it.

[Voltar1]

Valve spring force is about 5 percent of the issue.
To run a weak valve spring the closing forces come from other parts.

[miksatx]

What pray tell does no pressure forces have to do with the discussion?

Stop praying maybe that will help. I made a simple statement that the valve opened easier. I made this obeservence by doing this test I held a cothran valve in one fist and a p rod valve in the other and pushed down on the valve stems. the cothran pushed in easier.

[rsterne]

Here is a drawing of the valve, as I understand it, without the small rod inside the stem.... It is shown in the closed position.... Since the rod is a loose fit in the stem, and only acts as a "leaky check valve", when the valve is closed the pressure inside the head of the poppet is at atmospheric pressure.... I have also omitted the spring for clarity.... The stem (blue) and the poppet head (red) are threaded together and move as one unit.... Everything shown in black is fixed, the piston is bolted to the front of the valve....



The force holding the valve closed would be the air pressure of the HPA, acting on the area of the seat minus the area of the fixed piston.... If the piston area is half what the area of the OD of the seat is, the force holding the valve closed would be reduced by 50%.... Therefore, only half the force would be required to open the valve....

Please note the above drawing is not to scale, and is not intended to violate Mr. Cothran's rights.... it is intended to simply explain how the "Force Reduction System" he has invented works....

Back to you, Walter.... 

Bob

[rsterne]

Michael.... Your test is static and has nothing to do with the air pressure in the valve (because there wasn't any).... All you were measuring was the spring force.... That was Walter's point....

Bob

[miksatx]

Michael.... Your test is static and has nothing to do with the air pressure in the valve (because there wasn't any).... All you were measuring was the spring force.... That was Walter's point....

Bob

And your drawing is wrong Bob you left out the stabilizer piston that fits in the stem.

[rsterne]

and you didn't read my post.... I bolded where I covered that....

Bob

[Voltar1]

Piston pushs tophat/stem away from it closing valve

[rsterne]

Seriously, Walter?.... How does it do that?.... It's bolted to the front of the valve and doesn't move?.... Only the red and blue parts in that drawing move, and they move as one unit as they are threaded together.... The "top hat" slides on the O-ring on the piston, therefore the piston can apply no force to it....

Bob