Ball lift in a water pump.

[Dennis RaynerParticipant @dennisrayner52782]

I'm building a water pump and plan to use 7/32" balls on 3/16" seats. Does anyone know what I should restrict the lift to?

[Dennis RaynerParticipant @dennisrayner52782]

[Bob Brown 1Participant @bobbrown1]

1/4 the diameter of inlet hole size as anything above that gives no gain in flow.

[Dennis RaynerParticipant @dennisrayner52782]

Thanks very much Bob. That's very helpful (I'm trying to recover from miss-machining a casting which should have had 5/32" balls on 1/8" seats)

[Derek DroverParticipant @derekdrover32802]

I think most people aim for about 30 tho. Any more and you loose out on the time it takes to re-seat from the lift, especially if running fast.

D.

[Dennis RaynerParticipant @dennisrayner52782]

Thanks for that Derek – from the formula given by Bob I calculated 47 tho. so I'll settle on a value in between. This is for a steam operated water feed pump from a Southworth set of castings. I do not intend to operate it very quickly. With an injector and two axle pumps I'm not short of boiler feed so this will operate mainly for visual interest.

[Bob Brown 1Participant @bobbrown1]

If the seats were supposed to be 1/8" then 0.03" works and anything up to 0.047" would be fine.

As a cover all statement "I think most people aim for about 30 tho" does not work as you increase the size of the valve, a 1" valve with only 0.03" of lift would be a big restriction to flow. Time to re-seat is dependant on how the valve is re-seated, gravity or spring.

Bob

[Harry WilkesParticipant @harrywilkes58467]

I was once told by a wise man of steam the ball seat should 3/4-7/8 of the ball diameter and that the ball lift should never exceed a 1/4 of the seat diameter ! Having put this into practice on both clacks and pump on my engine everything now works fine.

H

[Author]

Posts