Whats the limiting factor that determines air compressor max pressure?

[Garett]

Very curious what determines an air compressors max pressure, reason being tied to my last post. I'm thinking I need more pressure to work my fully air operated wheel balancer.

If I daisy chain 2 single stage compressors, is it sorta like having a 2 stage pump? My 60 gallon is a conventional oiled air compressor with a rating of 135 psi max, thinking about adding a budget 15 gallon oil-less 200 max psi rated compressor on sale at my local store.

Will this work? What makes the 135 psi max compressor only good to 135 psi? I'm guessing the pump, would I need some 1 way valves?

 

[The Cobbler]

tank construction, HP of motor, pump ratiing is essentially the factors that determine your max pressure.
running two compressors is not like a 2 stage set up. 2 stage takes compressed air from one cylinder & compresses it again so you end up with higher pressures .
you can tandem compressors, but I would not put 200 psi into a 135 psi tank

 

[Jbullfrog]

You don't need more pressure, you need more volume. Get another big air tank and plumb it into your system. Most tire machines require 90psi into them.

 

[seagull369]

Exceeding the max pressure a given tool calls for is never really a good idea. Most would say fix whatever problem the tool is having instead of trying to compensate with a higher pressure .

Nonetheless, if I'm understanding you right, you want to plumb the output from the compressor on compressor 1 and feed it into the air intake of compressor 2. Instead of doing that, you may be better off adding a "T" fitting or manifold to the tank on compressor 2, if it doesn't have an unused port already. You could then connect a pipe from the tank output port on compressor 1 and feed that into that fitting on tank 2. Like you said, you would want to add some sort of 1-way valve in that line at some point, though I have no idea where you'd find something like that. Compressor one would help bring smaller volume compressor 2 up to 135psig quickly, then compressor 2 would continue on to fill itself the rest of the way. Pressure differential caused by tank 2 ought to cause that 1 way valve to stay shut, preventing backflow and pressure rising above max rated 135 in tank 1.

I have 2-60 gallon compressors I wanted to hook up together like that myself for really high demand tools, but in my case I was going to keep the pressure limited to whichever compressor has the lower psi rating.

 

[pstemari]

Long story short, for a piston pump the ultimate limit is going to be a combination of the cross-section area of the piston, the length of the throw arm on the crankshaft, and the torque applied to the crankshaft.

The force required to move the piston is just the pressure in the cylinder times the piston's area. The force applied to the piston is the length of the throw arm on the crankshaft times the torque applied to it, with an adjustment for the angle of the throw arm.

You can get a very high pressure with a tiny piston and just your arm, look at a frame pump for a bike. However, you're not moving much air when you do it.

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[Skin]

Pressure vessels have a fairly wide safety margin. Wouldn't surprise me if they were 4:1 like hoses so at 135max you're talking 500PSI before burst. If this is some unrated China thing might want to take that with a grain of salt though. Maybe safer to assume 2:1. The real limitation is stress on the pump and motor and of course the connections and tools. Most air tools, including balancers, are usually rated for 90-100PSI so you really shouldn't need more than ~150PSI for proper operation. Volume is a different story.

 

[Bigblockyeti]

1) As someone already stated, you likely have a volume or flow issue and not a pressure issue. It would be best to increase hose/pipe supply diameter or add a surge tank close to the machine.

2) Plumbing the two together could work but you need to see what the welded ASME tag states on the side of the pressure vessel. Some chinesium compressors do not have a welded tag, I will not use one, work on one, work around one or allow one on my property! In the unlikely event the 60 gallon pressure vessel would allow up to 200psi you still have a few obstacles to overcome before plumbing the two compressors together which include but are not limited to: The hardware connected to the 60 gallon tank not being designed for 200psi. The duty cycle of a "budget" oil-less compressor trying to fill 500% of its tank capacity.

The four hardware items that immediately come to mind on the larger compressor would be the pressure relief valve likely set at 150psi from the factory. The check valve between the compressor pump and the tank would likely be OK for a while at 200psi, but not designed for it. The diaphragm in the pressure cutoff switch may not be designed to handle that much pressure. Finally, the factory tank pressure gauge almost certainly wouldn't go to 200psi which would spring the bourdon tube.