Kollsman Autoschedule
Pressurization Control System
  Primary and Secondary Outflow Valves

 

Location - The outflow valves are located in the aft cabin at the bottom of the aft pressure bulkhead. 

View looking aft (Typical Installation)

1. Primary Outflow Valve
2. Secondary Outflow Valve
3. Max Differential Pressure  Safety Relief Valves
4. Max Altitude Safety Limit Valves
5. Vacuum Ejector Assembly
6. Dive Solenoid
7. Climb Solenoid

Operation - The primary outflow valve is electrically controlled by the cabin pressurization controller and pneumatically driven. The primary outflow valve incorporates two normally-closed solenoids: climb and dive, and an integral vacuum ejector.  Compressed air and vacuum are used to drive the primary outflow valve.  The secondary outflow valve is pneumatically connected to the primary outflow valve, forcing the secondary valve to duplicate the action of the primary valve.  The controller varies the position of the outflow valves toward open or closed by momentarily energizing open either the climb solenoid to raise the cabin altitude (decrease cabin pressure) or the dive solenoid to lower the cabin altitude (increase cabin pressure). 

Primary Outflow Valve

Pins

Functions

A Input (Ground) to dive solenoid from cabin pressurization controller (pin 11)
C Input (28 VDC) to dive solenoid from NORM PRESS circuit breaker
B Input (Ground) to climb solenoid from cabin pressurization controller (pin 10)
D Input (28 VDC) to climb solenoid from NORM PRESS circuit breaker