PREVOST LE MIRAGE XLII BUS SHELLS, Руководство по обслуживанию

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SD-03-2202*
of the shuttle or disc will reverse if the pressure levels are
reversed. Double Check Valves are designed so that the
shuttle or disc can never impede the backflow of air in the
exhaust mode.
Figure 3 (see page 2) illustrates a typical use of a Double
Check Valve to control a given device, such as trailer brakes,
from either of two control sources.
Figure 4 (see page 2) illustrates a typical use of a Double
Check Valve to supply air to a system or systems from
either of two separate sources, whichever is at the greater
pressure level. In this type of installation the pressure
differential to which the valve is subjected may under certain
conditions be minimal. It is therefore suggested that
performance of the Double Check Valve will be optimized if
it is mounted in the horizontal position.
PREVENTIVE MAINTENANCE
Every 3600 operating hours, 100,000 miles, or yearly,
disassemble, clean and inspect all parts. Install new parts
if they show signs of wear or deterioration.
DESCRIPTION
Double Check Valves are used in an air brake system to
direct a flow of air into a common line from either of two
sources, whichever is at the higher pressure. They may be
used for directing air flow for specific functions or to select
the higher pressure of either of two sources of air as a sup-
ply source.
AlliedSignal manufactures two types of Bendix Double Check
Valves: shuttle and disc. Although the valves are somewhat
different physically, the same function is performed by both
types. The difference in the design of the two valves is that
the shuttle type has a movable shuttle to seal off the lower
pressure source, whereas the disc type has a movable disc.
OPERATION
As air under pressure enters either end of the Double Check
Valve (inlet port) the moving shuttle or disc responds to the
pressure and seals the opposite port, assuming it is at a
lower pressure level than the other. The air flow continues
out the delivery port of the Double Check Valve. The position
DOUBLE CHECK VALVES
FIGURE 1 - DOUBLE CHECK VALVE (SHUTTLE TYPE) FIGURE 2 - DOUBLE CHECK VALVE (DISC TYPE)
DELIVERY
SUPPLY
SUPPLY
SHUTTLE
GUIDE
BODY
O-RING
SUPPLY
DELIVERY
SHUTTLE
VALVE VALVE
DISC
VALVE
GUIDE
BODY
CAP
O-RING
DELIVERY
SUPPLY
DELIVERY
CAP
*FORMERLY SD-03-67