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Air supply cfm
- Thread starter Dbovill21
- Start date
cvairwerks
Well-known member
At what pressure are they delivering those flow rates and at what pressure does your cabinet require that flow rate? Typical rating would be something like 12 cfm @ 100 psig..... (Note those are just random numbers for an example)
Like cvairwerks mentioned, if the flow rates you are specifying are at a pressure high enough for sandblasting you will likely be fine. Even if your overall flow is a little bit low, it just means you might have to stop sandblasting for 30 seconds every 2 minutes or so. Realize though, running three compressors to meet your flow needs will probably add more heat and moisture to the air than you would get if you had one larger compressor. Moisture can become a hassle when trying to run a sandblaster, so feeding three compressors into one shared tank without any sort of cooling or dehumidification might only work for shorter sandblasting sessions.
In my shop, I feed the air from two portable wheelbarrow style compressors into a larger shared supplemental air tank whenever I need a higher cfm capacity (not too often). The key with running multiple compressors is to make sure each one is plugged into its' own circuit. Ideally, you also want the compressors on different panel phases. If you want to run 3 compressors, you should put the largest compressor on a different circuit phase from the two smaller ones (I.E. the large compressor on black phase and the two smaller ones on red phased electrical panel circuits) so your home electrical system sees a more balanced overall load when everything is running.
If the lights in your home usually dim for a second or two whenever you turn on something like a vacuum cleaner or a powerful circular saw, you have a home electrical system that's on the more sensitive end in terms of inrush currents. Since the compressors will be sharing an air tank, they will all be seeing the same output pressure, so you will probably want to manually adjust your compressor cut on and cutoff pressures so they are a few psi up and down from each other. That way all the compressors won't be turning on or shutting off at the same time. The best scenario would be for the compressor that's on the second phase of your electrical panel to turn on and shut off second. That will help to minimize temporary voltage dimming or brown down issues from occurring in the rest of your home from the high compressor inrush currents.
In my shop, I feed the air from two portable wheelbarrow style compressors into a larger shared supplemental air tank whenever I need a higher cfm capacity (not too often). The key with running multiple compressors is to make sure each one is plugged into its' own circuit. Ideally, you also want the compressors on different panel phases. If you want to run 3 compressors, you should put the largest compressor on a different circuit phase from the two smaller ones (I.E. the large compressor on black phase and the two smaller ones on red phased electrical panel circuits) so your home electrical system sees a more balanced overall load when everything is running.
If the lights in your home usually dim for a second or two whenever you turn on something like a vacuum cleaner or a powerful circular saw, you have a home electrical system that's on the more sensitive end in terms of inrush currents. Since the compressors will be sharing an air tank, they will all be seeing the same output pressure, so you will probably want to manually adjust your compressor cut on and cutoff pressures so they are a few psi up and down from each other. That way all the compressors won't be turning on or shutting off at the same time. The best scenario would be for the compressor that's on the second phase of your electrical panel to turn on and shut off second. That will help to minimize temporary voltage dimming or brown down issues from occurring in the rest of your home from the high compressor inrush currents.
120 gallon says 125 psi the other one says 150 and it's 220v. 29 + 1/2 gallon compressor is 110 and it only does 125 unfortunately the larger one is a harbor freight one the other two are old Sears cast iron pumpsLike cvairwerks mentioned, if the flow rates you are specifying are at a pressure high enough for sandblasting you will likely be fine. Even if your overall flow is a little bit low, it just means you might have to stop sandblasting for 30 seconds every 2 minutes or so. Realize though, running three compressors to meet your flow needs will probably add more heat and moisture to the air than you would get if you had one larger compressor. Moisture can become a hassle when trying to run a sandblaster, so feeding three compressors into one shared tank without any sort of cooling or dehumidification might only work for shorter sandblasting sessions.
In my shop, I feed the air from two portable wheelbarrow style compressors into a larger shared supplemental air tank whenever I need a higher cfm capacity (not too often). The key with running multiple compressors is to make sure each one is plugged into its' own circuit. Ideally, you also want the compressors on different panel phases. If you want to run 3 compressors, you should put the largest compressor on a different circuit phase from the two smaller ones (I.E. the large compressor on black phase and the two smaller ones on red phased electrical panel circuits) so your home electrical system sees a more balanced overall load when everything is running.
If the lights in your home usually dim for a second or two whenever you turn on something like a vacuum cleaner or a powerful circular saw, you have a home electrical system that's on the more sensitive end in terms of inrush currents. Since the compressors will be sharing an air tank, they will all be seeing the same output pressure, so you will probably want to manually adjust your compressor cut on and cutoff pressures so they are a few psi up and down from each other. That way all the compressors won't be turning on or shutting off at the same time. The best scenario would be for the compressor that's on the second phase of your electrical panel to turn on and shut off second. That will help to minimize temporary voltage dimming or brown down issues from occurring in the rest of your home from the high compressor inrush currents.
In theory you can tie them all together and get a total flow that is about the same as the sum. This does assume you have independent electrical circuits to power them. Also, do think about safety. A critical point is are all the tanks rated for the peak pressure of the highest compressor? As an extreme example, tying a 200 psi compressor to a 125 psi compressor with a tank rated for no more than 160 psi isn't a good idea and *should* result in the blow off valve tripping on the lower pressure compressor.
If all of your compressors have the same pressure rating on the blow off valves you will be OK. However, if there is a big difference between cut off pressures then you will get a case where say one compressor turns off at say 125psi and now the 150 psi pump has to run a lot longer trying to fill both tanks. The extreme case is if the turn off/cut off pressure of one pump is lower than the cut in pressure of the other. If the pressure switch is adjustable this can be changed but it's just another thing to think about.
If all of your compressors have the same pressure rating on the blow off valves you will be OK. However, if there is a big difference between cut off pressures then you will get a case where say one compressor turns off at say 125psi and now the 150 psi pump has to run a lot longer trying to fill both tanks. The extreme case is if the turn off/cut off pressure of one pump is lower than the cut in pressure of the other. If the pressure switch is adjustable this can be changed but it's just another thing to think about.
It sounds like you're specifying the maximum pressure of each compressor. What we're saying is that the flow rate (cfm) for each compressor is typically specified at one or a couple different pressures. The most common are 90 and 40 psi. In other words, the sticker on the side of your compressor might say "10 cfm at 40 psi, 7.5 cfm at 90 psi" or something similar. In order to sustain blasting, your system will need to deliver some required cfm at some specified psi (the psi will be determined by the gun plus the jet/tip combo you choose and the manufacturers recommended operating psi for that setup).120 gallon says 125 psi the other one says 150 and it's 220v. 29 + 1/2 gallon compressor is 110 and it only does 125 unfortunately the larger one is a harbor freight one the other two are old Sears cast iron pumps
In any case, it sounds like you have a couple of 120 volt compressors and a 220 compressor. I doubt the 120 volt compressors can deliver 11.5 cfm at 90 psi (perhaps you meant combined?) so maybe those are the "40 psi" numbers. In any case, that at leart means you will be on different circuits as mentioned above. It also sounds like they will have different cut in pressures, though you may want to adjust the cut in pressures of one of the smaller compressors to make it kick on at a slightly higher or lower pressure than the other so they're not kicking on at the same time.
Otherwise, what you're describing sounds like it will work. The biggest problem will be moisture as described above. You'll need some length of pipe after the tank to cool the air plus a decent water trap/dessicant filter to get the air dry enough for blasting.
Also, one you get all your compressors daisy chained, you can do a timed pump up test to calculate how much actual cmf your system is producing and then you can size the jet/tip on your blaster appropriately.
Jswain
Well-known member
Sell all 3 compressors and buy a used 80 gallon 5hp 2 stage unit. If you already have an 80 gallon tank then sell all three compressors and buy a real 5hp motor of good quality and a 5hp pump
savage407
Well-known member
One big compressor is the best choice, if you can swing it. But if you do try to run all of the small compressors at the same time, reconnecting all for 240 volts will balance out the electrical load.
I read it off tagsIt sounds like you're specifying the maximum pressure of each compressor. What we're saying is that the flow rate (cfm) for each compressor is typically specified at one or a couple different pressures. The most common are 90 and 40 psi. In other words, the sticker on the side of your compressor might say "10 cfm at 40 psi, 7.5 cfm at 90 psi" or something similar. In order to sustain blasting, your system will need to deliver some required cfm at some specified psi (the psi will be determined by the gun plus the jet/tip combo you choose and the manufacturers recommended operating psi for that setup).
In any case, it sounds like you have a couple of 120 volt compressors and a 220 compressor. I doubt the 120 volt compressors can deliver 11.5 cfm at 90 psi (perhaps you meant combined?) so maybe those are the "40 psi" numbers. In any case, that at leart means you will be on different circuits as mentioned above. It also sounds like they will have different cut in pressures, though you may want to adjust the cut in pressures of one of the smaller compressors to make it kick on at a slightly higher or lower pressure than the other so they're not kicking on at the same time.
Otherwise, what you're describing sounds like it will work. The biggest problem will be moisture as described above. You'll need some length of pipe after the tank to cool the air plus a decent water trap/dessicant filter to get the air dry enough for blasting.
Also, one you get all your compressors daisy chained, you can do a timed pump up test to calculate how much actual cmf your system is producing and then you can size the jet/tip on your blaster appropriately.
Okay, so at what psi were the flow numbers you quoted rated?I read it off tags