110
1-body; 2, 6, 10, 14-springs; 3, 13-valves; 4, 12-diaphragms; 5, 11-guides; 7, 9-covers; 8-adjustment
screw; 15-return valve; I-outlet to the compressor; II, III-outlets to the brake system circuits;
а
, d-orifice
hole; b, c-side holes
Fig. 89 - The Four Circuit Safety Valve
If the air pressure drops in one of the circuits connected to the main outlets II and III, the
air pressure in outlet I and in the circuit connected to the main outlet in the good working order
drops down to the pressure of faulty circuit valve closing. The pressure in additional circuits falls
to the valve closing pressure.
5.5.2.6 Trailer Brake Control Valve with Double-Line Drive and Cut off Valve (Fig.
90), is intended for control of the trailer brake double-line drive. If trailer control mainline is dam-
aged or cut off the valve ensures pressure drop in supply line thus the trailer is braked automati-
cally.
5.5.2.7 The Acceleration Valve (91) is installed in the wheel brake system of rear axles
and reduces the brake drive actuation time by restricting the compressed air inlet from the air tank
to the actuator.
Compressed air from air reservoir is supplied to outlet I. Outlet II is connected to the
brake valve, outlet III is connected to the pneumatic chambers of axle brakes.
When there is no pressure in the outlet II the piston 2 is in the upper position. The inlet
valve 3 is closed because of the spring 4, the exhaust valve 6 is open.
The compressed air from the brake valve goes to the area above the piston - to the cham-
ber 1 and the outlet II. The piston 2 moves down under the influence of compressed air. The ex-
haust valve closes, the inlet valve opens. The chambers connected with the outlet III are filled up
with compressed air from the air reservoir through the outlet I and the open inlet valve. The vehi-
cle is braked by the axles brake.
