What Makes A Compressed Air System “Complete”?

It’s a good question.  When do you know that your compressed air system is complete?  And, really, when do you know, with confidence, that it is ready for use?

A typical compressed air system. Image courtesy of Compressed Air Challenge.

Any compressed air system has the basic components shown above.  A compressed air source, a receiver, dryer, filter, and end points of use.   But, what do all these terms mean?

A compressor or compressed air source, is just as it sounds.  It is the device which supplies air (or another gas) at an increased pressure.  This increase in pressure is accomplished through a reduction in volume, and this conversion is achieved through compressing the air.  So, the compressor, well, compresses (the air).

A control receiver (wet receiver) is the storage vessel or tank placed immediately after the compressor.  This tank is referred to as a “wet” receiver because the air has not yet been dried, thus it is “wet”.  This tank helps to cool the compressed air by having a large surface area, and reduces pulsations in the compressed air flow which occur naturally.

The dryer, like the compressor, is just as the name implies.  This device dries the compressed air, removing liquid from the compressed air system.  Prior to this device the air is full of moisture which can damage downstream components and devices.  After drying, the air is almost ready for use.

To be truly ready for use, the compressed air must also be clean.  Dirt and particulates must be removed from the compressed air so that they do not cause damage to the system and the devices which connect to the system.  This task is accomplished through the filter, after which the system is almost ready for use.

To really be ready for use, the system must have a continuous system pressure and flow.  End-use devices are specified to perform with a required compressed air supply, and when this supply is compromised, performance is as well.  This is where the dry receiver comes into play.  The dry receiver is provides pneumatic capacitance for the system, alleviating pressure changes with varying demand loads.  The dry receiver helps to maintain constant pressure and flow.

In addition to this, the diagram above shows an optional device – a pressure/flow control valve.  A flow control valve will regulate the volume (flow) of compressed air in a system in response to changes in flow (or pressure).  These devices further stabilize the compressed air system, providing increased reliability in the supply of compressed air for end user devices.

Now, at long last, the system is ready for use.  But, what will it do?  What are the points of use?

Points of use in a compressed air system are referred to by their end use.  These are the components around which the entire system is built.  This can be a pneumatic drill, an impact wrench, a blow off nozzle, a pneumatic pump, or any other device which requires compressed air to operate.

If your end use devices are for coating, cleaning, cooling, conveying or static elimination, EXAIR Application Engineers can help with engineered solutions to maximize the efficiency and use of your compressed air.  After placing so much effort into creating a proper system, having engineered solutions is a must.

Lee Evans
Application Engineer

Transmission and Motor Gears

This past weekend I spent some time pulling the transmission out of my ’93 GMC Sierra.  I’m of the mindset to get it together before the winter so I can take advantage of the 4WD, and maybe line the bed with blankets to catch a drive in before it gets too cold.

I was grateful to have a lift and a shop with air tools because it cut the time by at least 75%.  The last time I pulled a 4WD transmission without a lift it took at least 6 hours.  With a lift and a compressed air line, the time was just over an hour.  There was a momentary hangup with my air gun, though.

After the line pressure was established and the compressed had kicked off, I went to use my air gun and could tell there was something wrong.  There was plenty of noise, but a serious lack of power.  I checked the settings on the gun to make sure it wasn’t dialed down, and everything was fine.  Seeing me checking my hose connections and obviously having been through the same experience, my friend shouted “Oh yeah, that line doesn’t work.  Something’s wrong with it”.

I popped the air gun off to change lines and thought to myself – “I’m an EXAIR engineer.  I can’t go back to work on Monday if I don’t figure out why this compressed air line is faulty.”  So, I set out to find the root cause of my inadequate air supply.

I went through the basic checks and didn’t see any physical deformities in the air hose.  All of the connections looked to be sized properly, but I was still 90% sure I had a pressure drop somewhere.  Following the compressed air hose back to the rigid piping, I noticed a stand alone, manual drain filter for “my” line.  The filter was in series between the tee from the main line, and my compressed air hose.  “Viola!” I said.  I shut off the compressed air supply, drained the residual pressure, and removed the filter bowl.  It looked like something out of a coal mine!

With a new filter element and a thorough cleaning, the line pressure returned to normal and I was able to remove my trans before my buddy installed a water pump on a VW.  Still got it! :)

Remember to keep your filter elements on a regular maintenance cycle and avoid the dreaded pressure drop.

Lee Evans
Application Engineer