Chapter 107 Flashcards
Pneumatic control systems consist of four essential parts:
Air compressor, air pipping/tubing, controllers, controlled devices
What do pneumatic control systems operate by means of?
Compressed air signal
What pressure does the reducing valve maintain supplied air at?
103 kPa
What do the sensing elements on a pneumatic controller measure?
Change in temperature, humidity or pressure in controlled space
When the controller increase the control pressure on an increase in controlled condition it’s called?
Direct acting
What are the two classes controllers are divided into?
Bleeding, non bleeding type
The effective range of control pressure used in a 103 kPa circuit is usually considered to be between?
20-90 kPa
What are the three pneumatic controlled devices?
Dampers, pilot positioned, damper operators
What are the two basic types of dampers?
Opposed and Parallel blade
Pneumatic electric switches often control the operation of four pieces of equipment:
Valves
Pumps
Compressors
Fans
A pneumatic control systems uses a sensing device to change?
Pressure in the control line
The piston is sealed to avoid air leakage in a piston type damper operator by using?
Rolling diaphragm
The device used to maintain a constant pressure throughout a pneumatic control system is called?
A reducing valve
In a self contained control system the energy for operation is provided by the reaction of the?
Sensing device
The sensing element of humidistats reacts to a change in?
Humidity
