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Air compressor port size: 3/8 or 1/2?

snakyjake

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Oct 31, 2009
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I have a CH 60 gallon 135 PSI air compressor, and wondering what size port I should get for the filter/regulator. I noticed CH has the sizes 3/8" and 1/2". Both have the same specs.

Is 3/8" too small?
Is 1/2" overkill?

Thanks,

Jake
 
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Torque1st

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Why use a filter regulator?

Use a filter and/or a regulator at the point of use if required for the application.

A regulator just wastes all the energy that was used to compress the air above what is necessary.
 

DRJZ1974

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I have the same spec compressor in an Ingersol Rand and got the 1/2" filter/regulator. I also made sure to run "Full Port" valves to control my air. I wanted to make sure not to restrict my air flow.
 

Torque1st

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You're gonna have to explain that statement, because it just makes no sense at all.
I have explained that many times. You can look it up in many fluid power design manuals. It is like passing electric current thru a resistor to lower the voltage. The wasted power appears as heat. In a fluid when you lower pressure the energy that was contained in the fluid in the form of pressure and flow also appears as heat. The more you compress air the more power it takes. That energy is lost when the pressure is reduced. There are calculations that are performed when air systems are designed.
 
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Torque1st

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Eh, your mis-application of engineering theory has you all confused, but I'm too tired to debate it. Carry on.
Zrexxer, If you are a real engineer then you can look it up in your reference books and end your confusion. Maybe if you were not so "tired" you would remember something from thermo class. I tried to explain it in layman's terms. Sorry if they lack precision. Check the "horsepower to compress air" reference works. Remember energy is neither created or destroyed. :beer:
 

GeorgiaHybrid

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Torque,

With a given tank size, a tank pressurized at 175 psi will run slightly longer than a tank pressurized to 135 psi. If the output of the tank is controlled to 110 psi, you don't "waste" any energy. The only thing you are doing is regulating the rate the air pressure (energy) is distributed to the system.

If someone prefers to regulate the pressure at the tank and has tools that require the same pressure on their system, it makes no difference where that air is regulated as long as the CFM requirements are met. They will need to regulate the pressure to a higher psi at the tank compared to a regulator located at the point of use. Neither one will "waste" more energy than the other.
 

sberry

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Is 3/8" too small?
Is 1/2" overkill?
Neither, they will both work for this comp, the hose is usually the limiting factor in how fast the air can dump, usually only an issue with large air guns and almost never a problem for home/hobby shops. A 3/8 line will drain the unit faster than it can make it, most noticeable with rotary tools like grinders or sanders.
 

Torque1st

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Georgia, just look it up. It is in most air pressure reference works and I believe it is in Machinery's Handbook also. I am not going to argue about established facts and principles.
 
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GeorgiaHybrid

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I am not going to argue about established facts and principles.

Well, At least we agree on this much...... You must have had different classes than what we had in the old days. Either way, you have you opinion, I have mine and I will leave it at that. I do agree with you on not using PVC pipe and (just as a reference) my system has a filter/regulator at each outlet. Other than that, it's time to :beer: and put aside our differences.
 

4.0 Rambler

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Geneseo IL
One opinion is to separate the compressor from the user with a regulator. Since most tools are rated 90PSIG air pressure why supply them with more?

Put a regulator on the tank outlet and set it so all your supply system are at 90 PSIG. This will save you money in electricity, wear and tear on your tools, and wear and tear on your air compressor.
 

Torque1st

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Well, At least we agree on this much...... You must have had different classes than what we had in the old days. Either way, you have you opinion, I have mine and I will leave it at that. I do agree with you on not using PVC pipe and (just as a reference) my system has a filter/regulator at each outlet. Other than that, it's time to :beer: and put aside our differences.

Just look it up, expand your mind and understanding. It has been a known fact for at least 50 years that I know of.
The following article just mentions it but it points to a data reference from Womack that contains the information.
www.fluidpowerjournal.com/images/2008/FPJMA08/FPJMA08_AAA.pdf
The HP lost thru a regulator is obtained empirically from the tables of HP required to compress air but the calculations are simple. The idea is not intuitive but think back to Thermo classes, no matter how long it has been.:beer:
 
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