Double-Line Pneumatic Drive Of Trailer Brakes - Belarus 1822.3 Operator's Manual

tor; 9 – emergency air pressure lamp; 10 – pressure sensor; 11 – emergency pressure
sensor; 12 – tank; 13 – condensate drain valve.
Figure 3.9.1 – Single-line pneumatic drive of trailer brakes
Air is fed to the compressor 1 (figure 3.9.1) from the engine intake manifold through
the line 2. The air is compressed in the compressor 1 and delivered through the pressure
regulator 3 to the tank 12, from which the compressed air is fed to the brake valve 5. With
the brake pedals not pressed air goes to the connecting head 7 through the brake valve 5
and the control line 6 and further to the trailer brake pneumatic drive. The pressure regula-
tor 3 has an air bleed valve 4, which is used for tire inflation.
Air pressure in the tanks 12 is controlled by the air pressure indicator 8 with an emer-
gency air pressure lamp 9 (red color) in the instrument cluster as well as by pressure sensors
10 and emergency pressure sensors 11.
To remove the condensate from the tank 12 there is a valve 13.
The connecting head 7 is valve-type. The valve prevents compressed air from going
out when using the pneumatic drive without a trailer attached (when inflating tires). The
trailer brakes are controlled in two modes: direct and automatic. The direct control of the
brakes is performed by means of pressure drop in the connecting line 6 when the tractor
decelerates. In such case, delivery of compressed air to the trailer pneumatic system
stops. The automatic control of the trailer brakes is performed in case of emergency dis-
connection of the trailer and the tractor due to pressure drop to zero in the trailer connect-
ing line.
Note – Rules on checking and adjustment of the brake valve of the single-line
pneumatic drive are given in clause 3.9.4.2.2.

3.9.3 Double-line pneumatic drive of trailer brakes

The double-line pneumatic drive provides controlling brakes of trailers and agricul-
tural machines, equipped with double-line pneumatic brake drives, as well as tire inflation.
A diagram for the double-line pneumatic drive is shown in figure 3.9.2.
1- compressor; 2 – line from engine intake manifold; 3 – condensate drain valve; 4
– brake valve; 5 – feed line; 6, 7 – connecting heads; 8 – control line; 9 – tank; 10 – pres-
sure regulator; 11 – air bleed valve; 12 – air pressure sensor; 13 – emergency air pressure
sensor.
Figure 3.9.2 – Double-line pneumatic drive of trailer brakes
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