Two different sized pumps for same system

[Danaputnam]

Anyone know if you can add a second pump to a vacuum system that is smaller than the current pump? I have a setup where the pump is a bit undersized and have a smaller pump available. I would like to plump it in to add to the total CFM of the setup but am concerned that the bigger pump will take over or compete with the smalller pump vs the two pumps being additive. Does anyone have any experience doing this? Thanks

[Haynes Forest Products]

During a desperate time when my vacuum pumps were causing me fits I ran 2 gas powered pumps on the same releaser. I thought I was getting a better result until later on the pumps didn't sound good. Latter when on of the pumps quit i realized the one pump was sucking thru the stopped pump. I would put a check valve on both pumps to keep that scenario from happening. I wonder if you would be spinning the lower, slower pump?

[nymapleguy607]

If plumbed correctly I think it would work. You would need to make sure your pumps are attached in parallel vs in series, and the vacuum level must be the same at both pumps. I have seen pictures of large sugar bushes using multiple liquid ring pumps hooked in parallel.

[heus]

During a desperate time when my vacuum pumps were causing me fits I ran 2 gas powered pumps on the same releaser. I thought I was getting a better result until later on the pumps didn't sound good. Latter when on of the pumps quit i realized the one pump was sucking thru the stopped pump. I would put a check valve on both pumps to keep that scenario from happening. I wonder if you would be spinning the lower, slower pump?

Chuck you are back!!! Great to see.

[BreezyHill]

I have run a D73 an a d75 on the same system with no issues. They do need to have a swing check valve as does any pump to keep oil from getting to the releaser.

The 75 is atleast 3-4 times the volume of the 73. but the 73 will sucker higher vac. So the 75 will bring the system to 25" quickly and then the 73 takes the vac higher from there provided there is not large leak. If so the system doesn't hit the higher vac levels for me.

You will see the benefit of higher CFM from two pumps piggy backing. The only down side I saw I was not utilizing the capacity of both pumps so cost of power was little higher.

I know it has been done with piston pumps with good success from producer that was on here 2-3 years ago. SP series pumps.

I run a 3" PVC line from my electric releaser to a tee with the two pumps on each end of the tee. The oversized pipe makes it so neither pump is working to over come friction loses of a small pump.

Good Luck!
Ben

[nymapleguy607]

Ben, I'm assuming you have a delaval 75 pump, are you running a flood system to get your vacuum that high?

[Atgreene]

When I spoke to a leader rep at one of tge trade shows this winter, he was telling me that they've found that two small cfm pumps on the same system do better than a larger pump with more cfm. Two 8 cfms pull more vac than one 16 cfm. Didn't know why, but suggested that if I expand I may be better off buying a second small one.

[BreezyHill]

Yes delaval, but the 73 does not have a flood injector other than its normal common rail oil system. The 75 does have a dripper added to the inlet. The 75 does have a scratch in the face plate and is why she doesn't go as high.

When these pumps are fine tuned they can really do super well.