2 regulators on air compressor?

[gtr fan]

Hi everyone,

I just bought my first air compressor with regulator from supercheap auto.

I also bought a oil/water seperator, which has a regulator as well.

My question is should I run this second regulator / seperator as well or can I buy just an oil water seperator?

Thanks for any help.

[malb]

Regulators have some constant pressure drop and also a variable pressure drop proportional to the flow rate through them. If you cascade two regulators, you will have two lots of pressure drop, and the maximum pressure available after the second reg would suffer, particularly around the point where the compressor is about to cut in. Many tools are specced to operate at 90PSI and the switch is calibrated to start the motor at about 95PSI and cut out at 110-115PSI. This is done to ensure that the system should be able to maintain 90PSI output pressure.

With two regs in series, the input to the second would fall to about 90PSI at the low point of the cycle even if the reg is set for maximum pressure, so output could drop to 85PSI or lower at this point in the cycle.

Some options to consider include using the new reg to replace the original with possible warranty implications, connecting the second reg into a blanking plug in one of the tank ends (make sure to drain the tank daily/ after use as the take off point is a lot lower) or just installing an oiler or combined water trap/oiler at the outlet of the original reg.

[gtr fan]

Thanks Malb.

I suspected that it would reduce efficiency running 2 regulators inline.

I did not want an oiler unit because I heard they can be a bit messy with materials expanding when exposed to heat etc.

However I like your suggestion and will just get an oiler unit and leave the oil reservoir empty.

Thanks again.

Another stupid question, it says to use 10w 30 SAE oil in the compressor itself. Is this machine oil? its not motor oil is it?

[Cliff Rogers]

I have two regs & 2 tanks with a long hose between the tanks.

First reg set very high, second reg set lower than the first.

The idea of the long hose is to allow the air to cool before it gets to the second tank to cut down on the condensation. You get much dryer air at the spray gun.

I just went to a tool shop the supply & service compressors (not bunnies) & bought a tank off a buggered compressor for $30.

[malb]

I did not want an oiler unit because I heard they can be a bit messy with materials expanding when exposed to heat etc.

Another stupid question, it says to use 10w 30 SAE oil in the compressor itself. Is this machine oil? its not motor oil is it?


Sorry, I misinterpreted your original post, the second reg has an oil/water trap. I was thinking a water trap and an inline oiler. If you only want to clear moisture, the oil/water trap unit is OK, I was think you wanted to add inline oil for high use tools. The reg and trap unit you have should be fine to either replace the original unit, or to add as an alternative reg and trap. No need to buy a trap and oiler and run with the oiler dry. Alternatively you could just add a trap unit on its own.

Re compressor oil, you should be able to buy compressor oil at tool places, Bunnings, Supercheap etc. Similar grades to motor oil but no detergents etc as not needed as comp should not produce carbon buildups, varnish etc. Alternatively could probably use B&S 4 stroke oil, but I would not mix with existing oil unless you knew exactly what oil was installed at factory.

[thompy]

Another stupid question, it says to use 10w 30 SAE oil in the compressor itself. Is this machine oil? its not motor oil is it?

The SAE (SAE - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/SAE) is the Society of Automotive Engineers) and indeed refers to auto oils and the standardisation and measurement of oil viscosities.

It is motor oil, and it is a multi grade, and regardless of the detergents used if thats what it tells you to use then its what you should use, even though you wont have a carbon build or varnishes it will still require the cleaning, perhaps moreso without the filter in an auto application. If thats what its designed to take then i'd use it. I agree with not mixing old oils do a full change, and only top it up with your new stuff.

Neal.

[gtr fan]

Thanks guys for the explination regarding the oil, that clears that up.

Yeah Malb I ended up buying just a filter trap so I will take the regulator / filter thing back.

Had a bit of a play with it on the weekend, handy bloody thing, I wish I had bought one earlier.

Regards,

Rohin.