Single tank dual pump air compressor setup/hookup

[LJ973GM]

So here is what I am working with

80 Gallon tank that was for a single compressor originally

I have QTY of 2 twin piston compressors and two matching motors

I am looking for the correct way to tee them into the tank without causing damage to either compressor.

I drilled out and tapped the tank for a larger 3/4" intank check valve since I had one laying around.

Now if I just take the outlets from both compressors and tee them up and send them to the in tank check valve will there be any potential harm to the compressors due to one working more efficiently than one another. One motor has a smaller pulley than the other.

The unloader at the in tank check valve will bleed off the air from the unit when PSI setting is reached but my concern is that due to different size pulleys one pump could harm the other pump or render it useless by pushing back at it.

I am trying to find out if I need to use inline check valves for each compressor.

Both compressor are actuated off the same pressure switch.

I know this is not the most ideal setup overall but I am looking for a high CFM delivery and I had the spare motor and compressor sitting around.

I am going to run this at 175 PSI not sure what CFM I will achieve but it should be better than one single pump.

Hope the info listed above with help provide a correct answer for the setup if not ask away and I will do my best to answer.

Thank you for any insight.

 

[Toms Wheels]

You drilled out the TANK and fitted a second check valve. IF that means you drill through the tank shell and tapped the hole, My suggestion would be to torch the tank in two and place it in the scrap pile. If that means you drilled out one of those impossible to remove tank plugs and tapped that, then it sounds like you have it all set. as long as both compressors start/stop together, one check valve should work.

 

[Limy Sami]

When I did this (in another life) I used;-

Seperate check valves for each compressor with seperate connections to the reciever.

As long as both compressors will pump to the same pressure there shouldn't be any conflict.

+ 1 - If you butchered the reciever, either get it properly inspected and hydraulicly tested to insurance co standards or SCRAP IT!

 

[LJ973GM]

I drilled and tapped the welded plug that was in the tank already, it was a 1/2" I just enlarged it to 3/4" since it could not hurt anything and thought it might be needed for the added volume entering the tank from two compressors.

 

[Limy Sami]

I drilled and tapped the welded plug that was in the tank already, it was a 1/2" I just enlarged it to 3/4" since it could not hurt anything and thought it might be needed for the added volume entering the tank from two compressors.

Still a change - get it tested,........ at 175PSIG it migh not only be your ass if a reciever ruptures.

 

[LJ973GM]

I will take the liability that comes up on this one. It is a setup for my garage at my home.

The tank in up the attic and the pumps are below the ceiling in the garage. I have a auto water bleeder to make sure freezing the tank does not happen from being in a unconditioned space.

Tank label is rated to 300 PSI

 

[magneticanomaly]

I would not consider running two pumps in tandem unless each had its own check valve at the receiver (tank). Most receivers have lots of tapped ports. If you must run both pump outputs into one tank port, use the biggest tee that will fit into the port, and reducing bushings for the two check valves.

Two main reasons for my recommendation.

One is that the pump output is pulsatile. The pulsations of the two pumps will not be synchronized. You are likely to get all sorts of wavefront interferences and collisions in the discharge piping, if the two streams collide.

Two, if the discharge valves in the head of one of the compressors ever goes bad, at best your net pumping efficiency will go to hell, at worst you will damage or blow up a pump.

 

[LJ973GM]

magneticanomaly,

Thank you for the info. I did max out possible size on the tee and setup. Just was thinking afterwards that the inline check valves might be needed to stop harm as you stated could or will occur.

 

[Shawn Ghormley]

Will you have enough room on the plate for two pumps and motors? The Champion duplex I have, has two pressure switches.

 

[Shadon]

Far all intents and purposes, this is a 2 compressor system, just because they are running into a common receiver makes no matter.

2) check valves
2) motor starters
2) air pressure switches

In addition, I would adjust the 2 air pressure switches to "cascade" the motor starting, IE: have 1 switch lead the other, low demand on the system? 1 compressor starts and satisfies the switch, high demand on the system? both units run.

 

[LJ973GM]

Far all intents and purposes, this is a 2 compressor system, just because they are running into a common receiver makes no matter.

2) check valves
2) motor starters
2) air pressure switches

In addition, I would adjust the 2 air pressure switches to "cascade" the motor starting, IE: have 1 switch lead the other, low demand on the system? 1 compressor starts and satisfies the switch, high demand on the system? both units run.

I wish I had another entry point into the tank and I would just run two separate inlets to solve them fighting each other but I do not have that option.

 

[darkbreeze]

I realize this is a year late, however, I was intrigued by his problem, you stated, " I wish I had another entry point into the tank and I would just run two separate inlets to solve them fighting each other but I do not have that option.", my question would be, why? You said earlier in the post that, " I drilled out and tapped the tank for a larger 3/4" intank check valve since I had one laying around," so why can't you drill and tap and if necessary reinforce with a weld, a new input bung or fitting for the second compressor setup? Seems like it would actually have been less expensive to drill, tap and install a fitting rather than buying a T which is always the most expensive fitting at any line size. If anybody even cares.

 

[adama]

Stick a T on your new inlet and you have 2 separate entrances for each pump, add the separate check valves after there. Above all though you need 2 pressure switches so the pumps are separate, again just add a T below existing pressure switch and screw another in the other side.

If you really want more air though why goto 175psi? If you only need 100psi in practice you can change pulley size and make a lot more CFM that way for a given pressure!

Above all test that air tank, at 175psi it will if much over 50 gallons be capable of demolishing a single car garage just from the pressure release over pressuring the building.

 

[Cole2534]

Weld/thread-o-let

If one wants to add a tap the proper procedure would be to weld and NDT a thread-o-let onto the receiver. These manufactured fittings are designed to handle the stresses involved with adding a hole to the periphery of a thin wall vessel.

We use them all the time to pressures vastly exceeding you air compressor.

 

[complete loser]

No sense in starting a new thread. Ill just jump on this one.

I am doing something similar. However, both my pumps will be running off of the same motor. One pump and the motor are the factory setup for this compressor. Then im adding another pump I had laying around.

So the pressure switch is already installed with the first pump. Would I need to T off the pressure switch, and add to the new pump? (since theres only one motor, and its already controlled by the factory pump/pressure switch).

I was definitely going to do 2 check valves. However, should there be some 'buffer zone' between the two check valves? For instance, if I installed the check valves in a T, both valves across from each other, blasting one another, would the pulsations negatively affect each other being that close to each other?

Im thinking im just going to machine a Y block to atleast rule that scenario out.

 

[Limy Sami]

1st off, .....will the motor power handle two pumps ?

 

[Tony Quiring]

To last post...Check motor size as factory units usually close match meaning cheapest motor that will do the job is used.

To op...

Someone else beat us but with compressors mounted remotely or one local and one remote then just use a t at the tank and 2 check valves needed.

Use magnetic motor starters or just get some heavy contactor relays to actually control the motors.

Do use 2 pressure switches and offset them some.

If tank pressure is 175 and working pressure is say 90 then have one switch operate cut in at 100 and out at 125

Second whatever range is normal for the 175 total.

If you have a single stage compressor use it for low pressure.

Also note it needs to be continuous duty rated.

Add switches to control operation of either or operation.

You can control one or both motors by either pressure switch.

Single pump low
Single pump high
Both pumps low or high
One low and one high to allow staged or on demand.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk

 

[Lakeside53]

Dual check valves is not a given but the latest poster did not say what type of pumps he has. I have a factory duplex/tandem setup with no check valves. Quincy pumps output valves do not let air flow back.

 

[awake]

No sense in starting a new thread. Ill just jump on this one.

I understand your thinking, but ... necro-threads tend to make some of us very grouchy when we keep thinking, "haven't I read this before??" - and then find out the thread is 3, 5, 10 years old.

Not that I ever get grouchy, of course. It is always "them others." I am always kind-hearted and forgiving when this happens ...

 

[dickried]

I understand your thinking, but ... necro-threads tend to make some of us very grouchy when we keep thinking, "haven't I read this before??" - and then find out the thread is 3, 5, 10 years old.

Not that I ever get grouchy, of course. It is always "them others." I am always kind-hearted and forgiving when this happens ...

Yet the problem with starting a new thread is you will be told "this has already been discussed, use the search function." I would like to inquire what is proper protocol or etiquette when search function has been used and there are still questions unanswered?