GILLIG LOW FLOOR, Руководство по обслуживанию

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2
Air System
Check Valves
Check valves are used in many locations throughout the air system. There are several types of check
valves; the photographs shown here do not necessarily look exactly like the units installed in your bus.
Single Check Valve
Single check valves are used to permit the flow of air in one direction only and prevent air flow in the re -
verse direction. Figure 6-21, Figure 6-22, Figure 6-23, and Figure 6- 24 show typical single check valves.
An arrow indicating the direction of air flow is cast into the body of each valve.
operation
Air flow in the normal direction moves the check ball or disc from
its seat, and the flow is unobstructed. Flow in the reverse direction
is prevented by the seating of the ball or disc, which is caused by a
drop in upstream air pressure and assisted by the spring.
preventive maintenance
Every 50,000 miles, 6 months, or 1,800 operating hours, disassem -
ble, clean, and inspect all parts.
operation and leakage check
It may be easiest to simply remove the check valve from the vehicle
for testing. To test, apply air pressure to the outlet side of the check
valve. Coat the open end of the valve with soap suds. A 1" bubble in
5 seconds is permissible.
Figure 6-21, SC-3
Single Check Valve
Figure 6-22, Ball Type
Single Check Valve
Figure 6-23, Disc Type (inte-
gral seat) Single Check Valve
Figure 6-24, Disc Type (replace-
able seat) Single Check Valve