Compressed air fail: Pressure regulators

Figure 1. Each production machine in this plant had eye-level pressure regulators, however, a second main regulator was also installed within the machines.

By Ron Marshall

A newly constructed manufacturing plant had a policy to always install high quality pressure regulators for each one of their thousands of production machines. Each regulator was adjusted to the machine input requirements — and the pressure gauge marked it indicate the allowable range of adjustment.

Despite this effort, some production machines regularly experienced low-pressure shutdowns, so a compressed air auditor was called in to have a look. Data loggers were placed at the air compressors, after the air dryer, and at points along the plant piping. However, none of these instruments found any appreciable pressure loss.

But a look inside the production machinery told the real tale. There were regulators already installed on most production machines, the eye level regulators were usually redundant and the combination of the two had caused excessive pressure loss.

Figure 2. A second regulator was installed within each machine. The combination of the two caused excessive pressure drop.

For proper regulation, each regulator needs at least 10 psi differential between the input pressure and the local setpoint. This wasn’t being maintained for the second regulator, which caused poor resulting performance at the production machine.

Company policy has not changed, but now regulators will only be installed where required.