Compressed air filter/regulators

[wildcat]

I had a Milton poly bowl air filter explode recently (thankfully the shield was in place) and it got me thinking about what sort of filters/regulators should be in place. I have a two stage compressor with a cutout set to 175psi. Now here is most of the problem. The 175PSI is in excess of every poly bowl I have seen at 150psi. So it seems only metal bowls should be used but gosh most of these are approaching $100 and quite large. I assume most people here have two stage compressors. What are you using for compressed air filter/regulators?

Thanks

[Geof]

I have to ask; why are you using 175psi. that is high for air?

[wildcat]

I can only defend it by saying that is what the IR compressor came set at and I assumed the manufacturer knew best. I just checked the manual and it says that there is a factory preset of 40 +/- 4 psi difference between cut-in and cut-out (cannot be changed) and that default cut-in and cut-out settings are 135 and 175psi respectively. Are you suggesting that I should just lower the cut-out down to 150psi and be done with it? That would give a cut-in of 110psi... and then figuring line run loss... maybe I'm being greedy but if possible I would like to keep the pressure in the lines high and then regulate it near the point of use.

[Geof]

That is a very large differential. It means you are wasting a lot of electricity over-compressing the air which is eventually used at a lower pressure. Can you replace the switch with one that has a lower, and adjustable differential?

Also if you are running high to compensate for line drop you may find that over a few months you would save enough on the electricity bill for the compressor to justify running larger lines or put secondary reservoir tanks near the point of use.

If you have a clamp on ammeter you can look at the increasing motor draw as the compressor goes above 150psi. Also time how long it takes to get from 135 to 175 compared with 110 to 150 and then note how frequently it cuts in at the two settings. This will enable you to get an approximate number for possible savings.

[wildcat]

Very interesting suggestions... I guess I never really gave the increase draw of the motor any thought. I do realize there is an increase in load on the compressor as the psi grows so it only makes sense. I'll measure the current draw... that certainly will be interesting. I could probably afford a secondary tank by simply buying the 150psi FRLs instead of the higher pressure ones actually. I did visit an auto shop today and looking at how they had their air system setup. They compressed to high pressure as well and had absolutely no regulators except in the paint booths. They said their impact wrenches have a lot more powerful at the higher pressure. Thanks

[Geof]

...... They said their impact wrenches have a lot more powerful at the higher pressure. Thanks

Now that explains something that has always puzzled me; how are auto places able to rip threads out and strips nuts so efficiently? They run their air system way above what the impact wrench is rated for.