<BR> 1 = Pressure switch
2 = Non-return valve or ball shut-off valve
3 = Safety valve
4 = Control flange
5 = Manometer
6 = Ball shut-off valve
7 = Condensate drain
8 = Mounting for fittings
9 = Inspection aperture
10 = High pressure hose
Fig. 9.4: Compressed air receiver with fittings | The compressed air receiver is not simply a naked steel container. It needs a number of fittings to allow it to operate properly and assure the required safety.
- Pressure switch.
The switch is for controlling the compressor.
- Non-return valve.
A non-return valve must always be installed in the supply line from the compressor to the receiver. With piston compressors it prevents compressed air flowing back into the compressor during breaks in operation. With screw compressors the valve is integrated in the system.
- Safety valve.
The installation of a safety valve on compressed air receivers is required by law. If the internal pressure of the receiver p N (network pressure) rises 10 % over the nominal pressure, the safety valve opens and blows out the excess pressure.
- Control flange.
The control flange with aperture is used by the inspection authorities to connect a calibrated manometer for the pressure test.
- Manometer.
The manometer shows the internal pressure of the receiver.
- Ball shut-off valve.
The ball shut-off valve isolates the receiver from the pneumatic system or the compressor.
- Condensate drain.
Condensate precipitates inside the receiver and therefore it requires an appropriate connection for the condensate collector.
- Inspection aperture.
The inspection aperture can take the form of a socket end
or hand-hole flange. It is used to check and clean the inside
of the receiver. The minimum size of the aperture is
prescribed by law.
- High pressure hose.
The high pressure hose connects the receiver with the com-pressor.
It is used instead of a pipe so as not to transmit
vibration from the compressor to the pneumatic system
and to correct size deviations on connection to the system.
The pressure switch, high pressure hose and non-return valve are not typical fittings for compressed air receivers. But it is sensible to have them installed. |