What is Instrument Quality Air
In pneumatic instrumentation and control systems presently in wide use, it is frequently desirable to have available a source of air compressed to a pressure of about 20-25 psig for effecting pneumatic logic control and for positioning pneumatic valve and damper actuators and the like. Such systems are used in, for example, industrial and commercial buildings where a pneumatic scheme controls aspects of the heating, ventilating and air conditioning system. The presence of moisture in the supply of instrument air may have a deleterious effect upon the system since such moisture can corrode or obstruct parts of the control or actuator apparatus. Additionally, damper and valve actuators and the like may be located in a building adjacent outdoor air vents where they will be subjected to temperatures approximating the freezing temperature of water. Ice particles resulting from the presence of significant moisture within the instrument air system will have an adverse effect upon the performance of the pneumatic control system.