The pressure regulator is designed to regulate the pressure of compressed air coming from the compressor.
Compressed air from the compressor passes through the regulator outlet "IV" (Fig. 1), filter 2, channel 12, and is supplied to the annular channel 9.
Through the check valve 10, compressed air flows to outlet "II" and then to the vehicle's air tanks.
Simultaneously, through channel 8, compressed air enters cavity «А» under piston 7, which is loaded by the balancing spring 5. In this case, the exhaust valve 4 is open, and the inlet valve 11 is closed.
Under the action of the spring, the unloading valve 1 is closed. In this state of the regulator, the vehicle's pneumatic system is filled with compressed air from the compressor.
When the pressure in cavity «А» reaches 800 kPa (8.0 kgf/cm²), piston 7, overcoming the force of spring 5, moves up, valve 4 closes, inlet valve 11 opens, and compressed air from cavity «А» enters cavity «B».
Under the action of compressed air, the unloading piston 13 moves down, valve 1 opens, and compressed air from the compressor escapes to the atmosphere through outlet "III" together with condensate accumulated in the cavity, while the check valve 10 closes.
When the pressure at outlet "II" and in cavity «А» drops to 637 kPa (6.5 kgf/cm²), piston 7 moves down under the action of spring 5, valve 11 closes, and exhaust valve 4 connects cavity «B» with the atmosphere through outlet "I".
Then the unloading piston 13 closes under the action of its spring, and the compressor again pumps compressed air into the pneumatic system.
The unloading valve 1 also serves as a safety valve.
If the regulator does not activate at a pressure of 800 kPa (8.0 kgf/cm²), when the pressure increases to 1000–1300 kPa (10–13 kgf/cm²), valve 1 opens and the pressure is released.
Adjustment of the regulator is carried out with bolt 6: tightening it increases the activation pressure, while loosening it decreases it.
The activation pressure of the safety valve is adjusted by changing the number of shims installed under the valve spring.
The correct operation of the pressure regulator is determined by periodically monitoring the air pressure value during engine operation using the dual-needle pressure gauge on the instrument panel and the frequency of regulator activation.
During operation, the following malfunctions may occur: valve wear, clogging of the throttle hole in the piston.
The regulator is mounted on the left side member behind the third cross member of the vehicle's frame.
It is more convenient to remove the regulator when the vehicle is placed over an inspection pit.
To remove the regulator from the vehicle, unscrew the union nuts of the pipelines connecting the regulator to the compressor and the air tank, unscrew the nut, remove the washer, and the regulator assembly.
Disassembly and repair of the pressure regulator must be carried out by qualified personnel in specialized workshops.
Defective parts should be replaced during repair.
If the activation limits of the unloading device or the safety valve are exceeded, they should be adjusted. The pressure at which the regulator disconnects the compressor from the vehicle's pneumatic system is adjusted with the bolt.
