Piston rings

[Bill Shields]

Interesting since 99.999% of this type of pump use the water end piston and bore to limit travel and nothing slams into anything unless you run them dry then they click clack a little.

Wish you well with the journey...

[Chickens]

I have given the best discription of this pump and the way it works that I can as I see it. Only thing left to say is that it is working (with the two 0 rings per piston) and the exhaust ports in a quarter inch in from the cylinder heads. Anybody that has their own theories as to what is going on with it are welcome to them. I built the pump and (it is working).

[Bill Shields]

and pray you don't get a slug of wet steam (water) in there.

[Chickens]

Bill Shields - would you please explain why on earth that might happen. This pump was designed by someone who has disigned and developed the patterns, blueprints and castings of which many have been built successfully. Im sure if any of them had developed a slug of wet steam in them that he woldn't have been so sucessful in many of his indeavors. As I have said it's working. Your comments aren't worth responding to.

[Bill Shields]

Running on air is one thing and is a good test of what the unit will do once it attains operating temperature on the steam end.

Running on steam generally includes a start up period when the pump is cold and the steam condenses before it exhausts from the unit.

If you have a design that intentionally traps steam in a cavity during a portion of the stroke. it is very likely to condense into water and prevent full length stroke. This is called hydrolocking and can range from annoying to damaging.

On FULL SIZE pumps with this design feature.. they are generally fed bleed off steam..in through the inlet passages and out through drains specifically installed for this warm up period. Once the pump is hot and steam dry .. operation can begin

This is why I mentioned that most pumps of this type allow for some space at the end of the stroke that is always open to steam inlet and a drain.. it you do get a plug of water it will not hydro lock the end of the piston and potentially blow off the cylinder head.

On more standard designs the steam inlet remains open back to the slide valve so that the overpressure condition will only LIFT the valve from it's seat..allowing the water to escape without damage.

With your design, where the inlet port appears to be closed off as the piston reaches full stroke.. where can the water go?

Excess pressure can get between the o-rings and cause a pressure trap that will further bind the operation.

[Chickens]

[Chickens]

Fyi this is a page from the worthington/simpson duplex boiler feedpump manual. As can be noticed there are 2 (that's two) piston rings. You can bring up any number of duplex steam pump scematics and there will ALWAYS be 2 (that's two) piston rings. In the last paragraph (if you can read) in the valve adjustment it instructs the adjustment of the valve to prevent the piston from (slamming) into the cylinderhead. There ars a lot of good intentioned advice on these forums. Then there is a know it all that just sends you chasing your tail.

[NP317]

Oh oh...
RussN

[Harold_V]

Please lower the hostility level.

H

[Bill Shields]

You are absolutely correct - there are two piston rings as on most all of these designs.

perhaps it is better to learn the difference and application between piston rings and o-rings than to be accusing someone of tail chasing.

as I have said..I wish you well on your journey.

[RET]

Hi Chickens,

Bill is always worth listening to. He has a lifetime of experience in many fields.

Richard Trounce.