CFM measurements

all the devices on the machine have some type of displacement. Like a cylinder has so many cubic inches of volume in the cylinder. If double acting both sides of the swab.

convert the volume to cubic feet

the volume times the number of strokes in a minute equals the CFM of that cylinder.

air motor has a displacement cylinder volume minus rotor volume times rpm will give you CFM.

rule of thumb for air loss thru connections is none or what ever you can live with.

But the compressor rating is in free air delivered, or near enough in practice to SCFM (std. conditions are 70°F, 14.7 psia in US I believe). So also need to multiply your figure by working air pressure in psia/14.7. Or simpler, multiply by working air pressure in bara.

Codey

Here´s is a way to to check loses in your compressed air system. Make the plant silent by shutfing down all machines in the floor. Now the hissing sound of compressed air leaks stand out. Depending on the number of localizaed leaks figure 10-15% loses based on compressor rated output.

I HATE that sound! We go after those leaks with a vengence!

Likewise.

Since these are "custom built" machines, the builder probably doesn't have any "in service" technical data to offer.

One thing that would help is a nice sized air storage tank to help as a buffer for peak demand but ultimately, if the compressor is too small, you're in trouble.

Here's a suggestion, ask to speak with someone in the METERING DEPARTMENT at your local Gas Utility. They often have meters that were taken out of service for reasons other than faulty readings. They're quite accurate.
They may GIVE you one or at least LEND you one. You can put it in series with one or more machines.

Your best measurements would be to read it before and after each shift to get a good idea of cubic feet per day or shift. Short heavy demands can be covered by the buffer tank although a buffer tank can't realistically ride you thru an hour of excessive demand. A cubic feet per shift should easily determine your compressor's required capacity.

But are these meters OK for the pressure? Domestic gas meters work at 8" wg (in UK). Compressed air likely to be 80 - 100 psig. Worth checking before connecting up.

Also I think gas meters are positive displacement type so will read actual cfm at working pressure/temp, and need to correct for compressor duty.

Codemaster, You have a good point there, I do NOT know if they'll operate under 100 psi. BUT....I think they can operate under 40 psi. which is nominal un-regulated street pressure in Pennsylvania.

That's why I said, "ask the technician at a gas utility". My guess is they'd probably help you and they'd CERTAINLY know if it would work for you ( CLM711 ).

I don't think you'd want to put it in series with the whole plant but rather in series with each machine of like kind or maybe a whole department.

Ozzb and Ashman suggest determining cylinder volumes etc. but realistically, this information isn't available without dismantling a machine if at all.

There were lots of goood suggestions here though. Obviously, you'd want to track down leaks, they are an expensive waste of energy.

I suspect that energy is expensive for you too and THEREFOR... investing in a very high-efficiency electric motor for the compressor would also give you a quick return on your investment.

The reserve air tank is by far your cheapest solution to try because it allows a smaller compressor ( motor ) to work longer and therefor produce less electric DEMAND, which in most places is a penalty multplier for your kwh's used. Even if it doesn't totally solve the problem, storage tanks are good. They make nice buffers if placed through-out the plant and greatly reduce sudden pressure drops associated with long piping runs.

Unfortunately, for the price to buy a flow meter to analyze your air requirements, you can pretty much purchase a nice air reservoir....

Answer for you and for you calculations...First look at what the maximum volume at a certain presue is if all Pneu's acted at the same time. What is typically important is something called an air resevour. Keep enough volume and pressure in a resevour to maintain vale operation ay all time especially in critical fail. ( Which by the way all valves should fail safe ). So look at the cappacity of each cylinder, volume and pressure, maintain that much in a resevour but double it or get a compressor that ahs the cm capacity to make up twice the cylinders on the circuit. Tha is dam sue to be safe. Keep in mind the pressure relief valve issues. best!

P.S. Sorry about the spellig; it is difficult with no light and a half assedf monitor.

OK; I will retract my former statement. So here is your answer, ask your supplier to give you the spaec's at available P. If your P and volume doesn't match,,,,give it back to them. After all they are tere to serve. Go to Festo.com