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TMZ and D-AMZ Automatic Valve w/ Loss of Pressure Shutdown & Override

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The Chalwyn TMZ Bendix type automatic valve and D-AMZ Spindle valves utilize two automatic closure methods. They are designed to automatically stop an engine by closing down the air intake in the event of an engine runaway or overspeed condition. These valves incorporate a failsafe loss of pressure override mechanism that will also close the valve automatically with the loss of oil or pneumatic pressure signal from the engine control system. A manual start override/emergency stop lever is also included.

In addition, a flame trap housing with an optional integral air filter can be mounted directly on the smaller sized TMZ valves to reduce the size and complexity of installing the valve into engine packages where space is limited. The flame trap housings are available in two depths: ¾” (21mm) & 1½” (40mm)
The TMZ or D-AMZ valves are selected by combination of the air intake line bore size and the engine power at its rated speed. The size range for the valves is indicated below.

Automatic & Loss of Pressure Close with Manual Start/Stop

Engine Power

Air Intake Hose Size





TMZ w/ Flame Trap Housing
& Optional Integral Air Filter

7.5 - 93

10 - 125

40 - 96

2 - 3¾

TMZ (Bendix type)

7.5 - 179

10 – 240

51 - 108

2 - 4¼

D-AMZ (Spindle type)

80 – 600

107 - 805

76 - 229

3 - 9

Features and Benefits

  • Easy to install
  • Automatic air flow actuated closure on overspeed
  • Loss of pressure to close override
  • Manual start override/emergency stop lever
  • Flame trap housing and integral air filter available for smaller TMZ sizes
  • Trip setpoint calibrated on engine