One end of Bourdon tube 1 is connected by passage 8 to air tank 2, and the second, sealed, end is linked to regulating screw 3 of valve member 4. Chamber a of the valve is connected by passage 5 to the idling device of the compressor (not shown), and by passage b to the atmosphere. Located under valve 4 is plunger 6 whose conical tip blocks off passage 8. Upon an increase in pressure in the air tank, Bourdon tube 1 tends to straighten out, reducing the pressure exerted on valve 4. Then plunger 6, subject to increased pressure and the force of spring 7, moves upward, lifting valve 4. Passages 5 and 8 are connected together through hole b in plunger 6 and valve member 4 closes the hole for air discharge to the atmosphere. The pressure from chamber a is transmitted to the membrane of the idling device. This switches off the compressor delivering air into tank 2. As a result, the pressure in the tank is reduced.
$4273$CHP,Rg$