With out the check valves the first compressor to start will be filling
both tanks. Depending where the lower one cuts in at the first on can
override it by filling the other tank and you end up with one compressor
and two tanks. With the check valves you will only draw air from the one
with the higher pressure. I work with machinery that uses multiple air
supplies and we always separate the supply source with a check valve. This
way you can efficiently run the system with one compressor when your need
for air volume is low and only power the second unit when the demand is high.
At 17:45 9/3/99 -0500, Mike Frerichs wrote:
>With OR without the check valves you mention, the system will still work just
>as you described, as long as the pressure cut in points are different. See
>Eric Murray's post. He described it perfectly.
>Ronald Olds wrote:
>> I have an idea that should work well for this application.
>> Install a check valve on the outlet of both tanks and then "T" the two
>> lines together. This would not allow the air from one compressor to effect
>> the other. Then adjust one unit to cut in at a lower pressure. This would
>> allow both compressors to supply air equally until the air pressure drops .
>> Then the one set highest would cut in first. The compressor set lower
>> would only cut in if the pressure dropped low enough. The second
>> compressor would only be used when the air volume usage is high. This would
>> give you a primary and secondary unit. The primary one would be used most
>> of the time and the secondary only as required.
>> Ron Old