Larger ball check valve lift

[WindyParticipant @windy30762]

Been looking on the web to find the ideal lift for the larger ball valves on piston water and fuel pumps valves and at the moment hit a blank.

My model with 0.1875" balls has a lift of 0.014" restricted lift and is fine.

Is there a formula to determine the lift bearing in mind ball diameter piston diameter and stroke..

Any useful advice welcome thank you.

[WindyParticipant @windy30762]

[John OlsenParticipant @johnolsen79199]

The usual rule of thumb is that the lift should be no more than a quarter of the diameter. That provides an opening equal to the area of the hole. So a higher lift gives no extra flow, and increases the time taken for the ball to come back down when the flow reverses. Generally a smaller lift makes for less problems with the balls not seating properly, but of course you don't want to restrict the flow too much. The ball should not be able to move sideways too much either

The piston diameter and stroke don't bear directly on what the lift should be, but the hole should obviously be large enough for the flow expected. So a similar size to the pipe you would expect to use to carry the resulting flow would be reasonable.

(If you care to do the maths, you will find that the area of a round hole is equal to the (cylindrical) area between the ball and seat when the ball has lifted 1/4 of the diameter of the hole. The same applies for poppet valves. )

John

[FMESParticipant @fmes]

+1 for a quarter of the diameter of the ball.

Edited By FMES on 03/03/2019 09:44:57

[david homerParticipant @davidhomer12226]

Some information here may help

http://ibls.org/mediawiki/index.php?title=Design,_Care_and_Feeding_of_Check_Valves

David

Edited By david homer on 03/03/2019 10:10:53

[WindyParticipant @windy30762]

 

Sat on my arse designing the water and fuel pump body on Turbocad fortunately blown the model hydroplane pump drawing up apart from plunger diameters having to be changed.

Model pump is a very reliable design my ME forum members advised me on some very useful tables regarding the valve diameters and lifts regarding steam engines.

As usual at same time had Forces TV on as well a program just a few years old showing was Defenders of the Sky part I thought very interesting was modern Carbon Composites.

Brought back memories of a talk at my P.E.E.M.S. club about composites regarding aircraft and other uses.

At same time had some Presto taper shank metric reamers delivered they are used but nice and sharp another reasonable Ebay purchase certainly better quality than my last purchase.

For the mainly motorcycle top speed enthusiast there is a session at Elvington on Tuesday March 19th 2019.

 

Edited By Windy on 04/03/2019 16:00:28

[duncan webster 1Participant @duncanwebster1]

For full area flow you need more than 1/4 D lift, but I've read that for a high speed pump the ball lift should be well less than 1/4 or the ball doesn't have time to get back on its seat. They certainly get very noisy if the lift is excessive. I think Gordon Smith did an article in EIM some while ago about clack valves, unfortunately I don't get EIM, so can't supply copy.

[Author]

Posts