combining 2 pump flows into one

[muddstopper]

Easy answer, just get a pump with proper flow. Never one to do things the easy, or smart way, so here is the question. I have two identical pumps, same brand, same flow, same pressure. Neither pump is big enough by itself, but together they would provide the correct flow rate. Whats the easiest way to combine the flows to run just one circuit. Is it as simple as just tee the pressure lines together and then run one line from the tee to the control valve, is some type of check valves needed, should each pump have its own relief plumbed in before the tee. Yes, I know, one pump of the correct size is the best way to get the flow, but I dont have the right size pump, and I do have the 2 smaller pumps and I'm trying to utilize what I have on hand before trying to source more parts.

 

[J_J]

Each pump should have it's own check valve before the tee or Y.

 

[PILOON]

JJ, just curious, what if pumps were not same (like a 3 GPM and a 5 GPM) would that play out to be 8 GPM? and pressures also even out?

 

[Kyle_in_Tex]

If there is any pressure differential, wouldn't the higher pressure pump do most all the work,even with check valves? Better to sell both and buy 1 big one.

 

[bigdeano]

If they're both going to be turning all the time you wouldn't need anything but a T or Y. They're positive displacement pumps so they pump a fixed amount regardless of pressure. Even if they're not the same size they'll work fine just T'd together.

 

[J_J]

Since the pumps are supplying GPM's at a certain rpm, you have a combined flow.

The pressure will be dictated by the load on the pump.

Say you had a combined flow of 10 GPM's, and a hyd component that can develop about 3000 psi, then you will need 21 HP for that situation.

Now, the 4 GPM pump drops out, that leaves 6 GPM, then the HP requirement now becomes abut 12 HP.

 

[muddstopper]

Since the pumps are supplying GPM's at a certain rpm, you have a combined flow.

The pressure will be dictated by the load on the pump.

Say you had a combined flow of 10 GPM's, and a hyd component that can develop about 3000 psi, then you will need 21 HP for that situation.

Now, the 4 GPM pump drops out, that leaves 6 GPM, then the HP requirement now becomes abut 12 HP.

Why would the 4gpm pump drop out if both are pumping at the same time. I can see internal wear and tear maybe causing the worn pump to bypass some internally if the pressure required became more than the worn pump could make. But if both pumps where capable of making the same amount of pressure, why would one drop out

Each pump should have it's own check valve before the tee or Y.

If in the event that the pressure exceeded what one of the pumps could make, wouldnt using a check valve act as a block to the lesser of the two pumps, causing a blown pump. I am thinking a relief in line before a check valve might be a safer method to prevent back flow thru one pump

 

[SSdoxie]

Tee the 2 outlet lines together and use 1 relief valve in system after the T. The Hi-flow version of Bobcat Skid Loader has been dong this same thing for 20+ years. It works fine. No check vavle required unless the was reason to select flow from 1 pump only and send the other pump flow directly to tank.