Air pressure regulator

AIR PRESSURE REGULATOR

1. What are Air Pressure Regulators ?

• Function: The function of the air pressure regulator is to regulate the pressure of the incoming compressed air so as to achieve the desired air pressure at a steady condition.

• The compressed air leaving the compressor should be properly prepared before it goes into the circuit. The air should have the proper operating pressure for the circuit. Improper fluctuating pressure level in the piping system can adversely affect the operating characteristics of the system components such as valves, cylinders, etc. Therefore, air pressure regulators are fitted to ensure the constant supply pressure irrespective of the pressure fluctuations in the compressor unit.

• For example, the line from the compressor may carry a pressure of 10 bar, the air pressure regulator can reduce this pressure to 0 bar to any point between the full line pressure and zero pressure.

• Thus the air pressure regulators act as pressure guards by preventing pressure surges or drops from entering the air circuits.

• Types: The two types of air pressure regulators are:

1. Diaphragm-type regulator, and

2. Piston-type regulator.

• Diaphragm-type regulator is commonly used in industrial pneumatic systems.

2. Construction

The construction and operation of a typical diaphragm-type air pressure regulator is illustrated in Fig.11.9(a).

It consists of diaphragm, valve, main and dampening springs, etc. Usually the diaphragm is made of oil-resistant synthetic rubber with a nylon cloth reinforcements.

3. Operation

The diaphragm allows the proper amount of movement for opening and closing at the valve seat. When the adjusting screw is in the fully retracted position, the valve is closed. When the adjusting screw is turned to compress the adjusting and dampening springs, the valve is opened. Thus the air is allowed from inlet port to the outlet port.

The pressure of the outlet air depends upon the size of the valve opening that is maintained. This is determined by the compression of the adjustable spring. Higher the spring compression, more will be the amount of opening and hence more the pressure and vice versa.

The vent-holes are provided to let out the undesirable excessive outlet pressure, if any, into the atmosphere. The dampening spring is provided to act as a dampening device needed to stabilize the pressure.

4. Graphic Symbol

Fig.11.9(b) shows the graphic symbol of the air pressure regulator.