Waterproof Improvement for Pneumatic Braking Valves

Challenge

During the utilization of pneumatic braking valves (typically in commercial vehicles), exhaust port (3) is open to external atmosphere. In extreme circumstances (e.g. flooding) water could enter the device through exhaust port (3), as the device is submerged in water, as illustrated in the schematic diagram above.

Current pneumatic braking valves structure:

Chassis mounted

2 working steps

• Braking: Generates brake pressure up to 13 bar (nominal ~10 bar).
• Braking pressure release: Releases pressure from 13 bar to 0 bar through port 3 within approximately 500 milliseconds with an air volume of > 2 liters.

For the waterproof improvement solutions, it is required:

1. No water penetration: The pneumatic braking system should remain watertight during multiple brake and release cycles while the vehicle is immersed in a water depth of >1.2 meters for up to 5 hours. Specifically, water should not enter through the exhaust port when the vehicle is driven back and forth in a flooded area.
2. No degradation of air pressure release performance: The proposed solution(s) should not cause any degradation in the timing or duration of air pressure release. The release should meet all existing specified requirements.
3. No increase of exhaust noise: The improvements should not result in an increase in exhaust noise during the braking and release processes.

Searching one solution which could avoid water ingress into pneumatic braking valves when device is immersed in the water, meanwhile will not degrade the exhaust time and exhaust noise. 

Important Note: Solutions that involve adding an additional check valve will not be considered since any remaining air pressure should not exist after the exhaust process.

Only innovation applications are required at this time.