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| Illustration 1 | g00106826 |
Quick release valve in the APPLY position (1) Outlet port (2) O-ring seal (3) Cover (4) Inlet port (5) Diaphragm (6) Body (7) Exhaust port (8) Plug | |
The quick release valve hastens the exhaust of air from the brake cylinder on the scraper. The quick release valve can be in one of the following three positions during operation:
- APPLY
- HOLD
- RELEASE
The quick release valve is in the APPLYING position when air pressure passes through the valve into the brake cylinder. The quick release valve is in the HOLD position when air pressure is held in the brake cylinder. The quick release valve is in the RELEASE position when the brake cylinder exhausts.
In order to apply the service brake, air pressure enters inlet port (4) and the air pressure moves diaphragm (5) downward. This closes exhaust port (7) and the outer edges of the diaphragm are deflected downward. Air pressure passes through outlet port (1) to the brake cylinder.
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| Illustration 2 | g00106827 |
Quick release valve in the HOLD position | |
When the cylinder pressure below the diaphragm equals the lock pressure above the diaphragm, the edge of the diaphragm (5) is forced against cover (3). The center of the diaphragm continues to cover exhaust port (7). This is the HOLD position.
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| Illustration 3 | g00106829 |
Quick release valve in the EXHAUST position | |
When the brake pedal is released, air pressure on the top of the diaphragm is released. The cylinder pressure below the center of the diaphragm raises the diaphragm, which opens port (7). This permits the air from the brake cylinder to exhaust.