The Steamboating Forum

Howdy,

I am playing with a hand pump and have a question. It is the simple "2 ball Bearing" internal check valve design and one of the ball bearings is missing and I cant find an easy local source. Couldnt I remove the other ball bearing and just put a check valve on both the inlet and outlet side ? It seems like it would accomplish the same thing.

jon

Ideally the check valves, which is all these ball valves are, are best as close to the pump cylinder as possible for efficient fill and scavenge of the pump, but that's not to say they wouldn't work if mounted further away but there may be some loss of efficiency.

The dia. of the ball is critical, as is the amount of lift allowed when operating. They are most unlikely to be different sizes, but should be stainless or bronze rather than plain steel (rust). Check out the model suppliers if you're having difficulty in obtaining one.

Ordinary screwed check valves can work OK, but better to get the ball you need. I have a supply of brass and stainless balls, what size do you need?

Hey Fred,

1/2" is too small................5/8" is too big............

jon

Measure it's mate, with a vernier caliper! They should be the same.

My hand pump is 1" bore by perhaps three inch stroke with external check valves. Works great. On an engine driven pump I might worry more. It might clack too much if things weren't right. But the hand pump just needs to always work when you need it.

Mike

Actually, they arent............the ball on the intake side is significant smaller........perhaps I have an issue........

You may, but not necessarily, I would have expected it the other way round, if at all, bigger port on the inlet as it's only atmospheric, not pressured. It may have been done to keep it quiet.

If you think 9/16" is the size, then Reeves 2000 hold stock in P.B., but not cheap. £5 a throw!

http://shop.ajreeves.com/phosphor-bronz ... 6876-p.asp