RECOVERY VEHICLE, FULL TRACKED: MEDIUM, M88A1
FIXED FIRE EXTINGUISHER SYSTEM THEORY OF OPERATION
Fixed Fire Extinguisher System
The M88A1 is equipped with a fixed, carbon dioxide, fire extinguisher system for smothering fires in the engine and winch
compartments. The system consists of eight 10-lb (4.5-kg) cylinders (1), a cylinder control valve (2), remote control connectors
(3), two dual-pull mechanisms (4), extinguisher lines, seven nozzles, two exterior remote control pull handles (5) with cables,
two interior remote control pull handles (6) with cables, and an engine shutoff switch (7) (to ensure the engine is turned off before
the fixed fire extinguishers are discharged). Each cylinder is equipped with a safety valve that automatically discharges when
pressure becomes excessive due to heat. The cylinders are mounted in banks of four on each side of the cab interior.
Figure 1. Fixed Fire Extinguisher System.
The engine shutoff switch (7) consists of a push button switch assembly (electrically connected in series with the engine fuel
shutoff solenoid and the vehicle batteries), which is depressed (open circuit) during vehicle operation by an adjustable screw
mounted on a hinged metal shield held in position by a quick-release pin. When it is necessary to discharge the fire extinguisher
system, the push button on the quick-release pin is depressed, allowing the shield to pivot downward, which releases the
adjustable screw from the push button on the switch assembly and activates the fuel shutoff solenoid, shutting off the engine.
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