Shuttle Valve for diaphragm pump

814jeffw

814jeffw

Active member
Just wondering if anyone has any experience with plumbing in a shuttle valve on an air diaphragm pump. A shuttle valve keeps the pump from stalling between starting and stopping the flow of fluid. I understand the way it works,( I think)
But the third port has me a little confused. Tried to find a schematic online, but no luck. Thanks!
Shuttle Valve

Jeff
 
cajun cleanin said:
The shuttle valve should already be installed between the two heads of the pump.The middle where the air hooks up is the shuttle valve it is internal.

Show us some pics if this is not the case so we can see what type pump it is.
Click to expand...

Thanks, and yea this is a Yamada NDP 15 which already has a no-stall valve installed,...but through some research it seems they're not always fool proof. Some work better than others. From what I've found an external shuttle valve is the remedy. My pump doesn't do it every time. And I'm hoping this added valve may eliminate the issue altogether. Even on the Yamada site under "ideal installation" it shows the use of a solenoid valve. I think it does basically the same thing as the shuttle valve, although I'm not 100% on that. Any insight is appreciated.

Thanks,
Jeff

Jeff
 
A soleniod valve only cuts the air on or off.A shuttle vale and a soleniod are two different things.The shuttle valve is what applies are to the diaphagms in the pump.The shuttle shifts right and the air pushes the diaphragm on one side out and it pumps the other diaphragm is being pulled in at the same tie and it is pulling material in.It is like a heart kinda one side is always pulling in and one side is pumping out.If the pump is not pumping or you hear air bypassinf thru it it is a shuttle stuck.If the material sprays out the exhaust port then the diaphragm is blown.If the pump sounds right and is not spraying from the xhaust and still will not pump it is probably something stuck in one of the ball checks.There should be 2 on the top and 2 on the bottom.If the balls can't seat it will just cavitate or pump just a little.

If the shuttle is sticking you may need to add an oiler to the air supply line before the pump.Air in itself unless you have a dessicant dryer is wet and it will cause the shuttle to rust and stick.The oile will lubricate the air intake with very small increments of oil as the air passes thru the oiler.
 
Thanks, maybe I will try the oiler. That was a very informative post by the way. It's done it since day one, so I'm not sure what's going on. The way I fix the problem currently is to shut the air on and off with the supply valve and it starts pumping again.


Thanks,

Jeff
 
Back at the Refinery, we had to oil those air-diaphragm pumps or they would stick or when they stop, we would take the air hose off, disconnect the outlet and pour in oil or transmission fluid and it would start working again.

That is a very good point. Most air systems have air dryers to get the moisture out and oilers for the air tools that need lubrication.

I bet if you just added an oiler, it would take care of the problem, run the pump for a while to see if you only need a little bit of oil and if it keeps sticking, keep increasing the oil until it runs a while without sticking.





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Yea, the oiling idea sounds like the route I need to take. I don't know why I never thought of that, I have air tools that oil,...only seems to make sence now that it's been brought to light.

Thanks again fellas,

Jeff
 
Great info Cajun.. thanx!.

Jeff are you concerned about the diaphragms not pumping when yer not spraying or is it just bypassing air or water? They should stop and everything should hold pressure far as I know. Mine tend to end up leaking after a little bit and then start cycling again for a brief time. The whole on demand thing is part of the beauty of pumps.
 
What I'm talking about Kevin, is when I turn the fluid outlet off and then try and then when I turn it back on again to start spraying again, it doesn't start pumping again,....So I have to simply turn the air supply to the pump on and off and it starts back up.

Jeff
 
These pumps are positive displacement pumps they will pump untill the pressure inside meets the air pressure.In other words if you have 100 psi air it will pump to 100 psi or it will by pass air out of the exhaust.

There is a timing shaft in these pumps that will bend if you use it like a shurflo or other pump that meets the pressure and shuts off.If the shaft bends if won't pump it will only bypass.If you use it and it stops pumping from high pressure it is putting whatever psi your air pressure is on this shaft.
 
It never stops while the outlet valve is open, it only stops when you shut off the outlet valve and then turn it back on,....but not always I'd say probably 2-3 times on an average roof job. It pumps great when it's pumping. I think it may be the oiling issue that has been brought to my attention. Cajun seems to know some serious details about the inner workings of these pumps. Great information!!

Jeff
 
I see what yer saying Cajun, kinda like a crankshaft siezing up eh?..wonder if various brands are as susceptable as the next as they all about similar? Maybe the oil will free it up or maybe turning the pressure down will keep it from acting up. The ones I have never fail to start turning but I only put them to about 80psi.
 
Nice Tip JC

cajun cleanin said:
A soleniod valve only cuts the air on or off.A shuttle vale and a soleniod are two different things.The shuttle valve is what applies are to the diaphagms in the pump.The shuttle shifts right and the air pushes the diaphragm on one side out and it pumps the other diaphragm is being pulled in at the same tie and it is pulling material in.It is like a heart kinda one side is always pulling in and one side is pumping out.If the pump is not pumping or you hear air bypassinf thru it it is a shuttle stuck.If the material sprays out the exhaust port then the diaphragm is blown.If the pump sounds right and is not spraying from the xhaust and still will not pump it is probably something stuck in one of the ball checks.There should be 2 on the top and 2 on the bottom.If the balls can't seat it will just cavitate or pump just a little.

If the shuttle is sticking you may need to add an oiler to the air supply line before the pump.Air in itself unless you have a dessicant dryer is wet and it will cause the shuttle to rust and stick.The oile will lubricate the air intake with very small increments of oil as the air passes thru the oiler.
Click to expand...
 
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