Pto driven water pump

hosspuller · Feb 19, 2014

The roller pump is a positive displacement device. That is ... if you dead head or block the flow, something has to give. Either a relief valve or pressure regulator. If you don't allow for over pressure, it will be expensive or dangerous or both.

usually a pressure regulator is used with the excess flow going back to the tank. The diagram you posted does not have any relief valve shown. The system as shown is dangerous. Close the agitator valve and the boom valves = dead headed system.

Desert Bred · Feb 19, 2014

Thank you. I found a better diagram that reflects what you wrote : I'm hoping the pressure relief valves aren't as expensive as what I have found so far..

hosspuller · Feb 19, 2014

Relief valves are simple & cheap. Besides pressure rating you must size it for the max volume of the pump. Example: A 2 gpm relief valve on a 200 gpm pump isn't much protection. Even when relieving, that system will build pressure at the rate of 198 gpm

Desert Bred · Feb 19, 2014

hosspuller said:
Relief valves are simple & cheap. Besides pressure rating you must size it for the max volume of the pump. Example: A 2 gpm relief valve on a 200 gpm pump isn't much protection. Even when relieving, that system will build pressure at the rate of 198 gpm

So for a http://bit.ly/1oTApFppump rated max 19.6 gpm would you attach a 20 gpm relief or would you go lower?
Btw thanks

hosspuller · Feb 20, 2014

If the pump will produce 19.6 gpm at 540 rpm, And you're going to run it at 540 RPM then I would install the 20 gpm relief valve. Use large enough pipe to carry the 20 gpm too ... You do not want to reduce it to 1/4 inch tubing lol !

Remember, a relief valve is held closed by a spring. When the pressure is more than the spring can hold, the valve opens. When the pressure falls below the set point, the valve will close. Some relief valves are adjustable, others are permanently set at the factory.

It's the fluid equal to a circuit breaker.

Desert Bred · Feb 20, 2014

hosspuller said:
If the pump will produce 19.6 gpm at 540 rpm, And you're going to run it at 540 RPM then I would install the 20 gpm relief valve. Use large enough pipe to carry the 20 gpm too ... You do not want to reduce it to 1/4 inch tubing lol ! Remember, a relief valve is held closed by a spring. When the pressure is more than the spring can hold, the valve opens. When the pressure falls below the set point, the valve will close. Some relief valves are adjustable, others are permanently set at the factory. It's the fluid equal to a circuit breaker.

Awesome and good point about the return size pipe size. I've been reading a lot it seems -about something as simple as this - I appreciate the help . I've tried Google eBay CL just to get an idea of price and I think I found a few (been seeing a lot of different kinds) but pricing is over 50 which makes me think I haven't been either looking in the right place or Im being overly cautious - I've been trying to understand if they are rated by gpm or psi when I read your last response. Things come together quickly with the help of this forum so I'm going to keep on looking maybe to find some more options I'm thinking it would be easier to find it online rather than ace or some other place but if you or anyone has any experience buying one at a good price (or say around 20$) let me know .. ok ramblin on here thanks

hosspuller · Feb 21, 2014

Since you're building a sprayer... you might check what regulator is used on sprayers. My sprayer has a regulator that relieves excess flow back to the tank.... combining regulator & relief functions into one unit for less cost.

Briar Hill Brittanys · Feb 22, 2014

Here's my home built sprayer. Pump is a Silver Series 6 roller Hypro, PTO driven. Suction and discharge from the pump is 3/4" hose, plastic manifold piping, solenoid valves, and relief valve and discharge hose are 3/4" ID. The relief discharge continues to the bottom of the tank and functions as an agitator, keeping the solution mixed. The boom and wand are fed with 3/8" hose. The flood tips I use spec a recommended pressure of 40#, @ 20" above the plant. To achieve this pressure, I start the pump running with the valves closed and adjust the relief to about 44#. When the valve to the boom is opened, the pressure levels out at 40#. When using the wand I adjust the pressure to get the distance of spray I want. Here's a link to the relief valve, it was a little cheaper a couple of years ago. Hamilton Pressure Regulating Bypass Valve, Nylon, 3/4 in. MNPT Inlet x 3/4 in. FNPT - Tractor Supply Co. . The second picture shows the distance sprayer will reach when the wand is dialed down to a stream. About 40'. Mark

Desert Bred · Feb 22, 2014

Briar Hill Brittanys said:
Here's my home built sprayer. Pump is a Silver Series 6 roller Hypro, PTO driven. Suction and discharge from the pump is 3/4" hose, plastic manifold piping, solenoid valves, and relief valve and discharge hose are 3/4" ID. The relief discharge continues to the bottom of the tank and functions as an agitator, keeping the solution mixed. The boom and wand are fed with 3/8" hose. The flood tips I use spec a recommended pressure of 40#, @ 20" above the plant. To achieve this pressure, I start the pump running with the valves closed and adjust the relief to about 44#. When the valve to the boom is opened, the pressure levels out at 40#. When using the wand I adjust the pressure to get the distance of spray I want. Here's a link to the relief valve, it was a little cheaper a couple of years ago. Hamilton Pressure Regulating Bypass Valve, Nylon, 3/4 in. MNPT Inlet x 3/4 in. FNPT - Tractor Supply Co. . The second picture shows the distance sprayer will reach when the wand is dialed down to a stream. About 40'. Mark http://s971.photobucket.com/user/briarhhillbrittanys/media/Sprayer003.jpg.html http://s971.photobucket.com/user/briarhhillbrittanys/media/Sprayer008.jpg.html

So many thanks for that link I have been looking and to no avail..

I found those other pictures - the plumbing diagram.. here

now the question i have is - are the pressure gauge and the pressure relief valve plumbed oppositely.. that after the roller pump comes the relief? so the series is:
tank - strainer - PUMP - pressure relief - solenoid (to sprayer) -solenoid (to boom) - guage

lost a bit if thats not the case and.. the solenoids.. they're plumbed by a 'T' fitting.. and the outlet of each solenoid is where the hose drops from 3/4 to 3/8 line
?
I found this picture after that one..so i'm editing this to throw it in.. must have been version before the above one.. so that as long as the relief and gauge go before the ball valve (or solenoid in your case) we can see the pressure that will be going to the sprayers.. and all plumbs well. got it.