CDL Air Brakes TestDual Air Brake SystemsHard
A dual air brake system relies on separate air tanks for the primary and secondary systems. What critical component prevents air from flowing back out of these tanks if the air compressor or supply line fails?
- AThe brake pedal treadle valve.
- BThe governor valve.
- CThe safety relief valve.
- DThe one-way check valve.
Show answer & explanationAnswer & explanation
Correct answer: D. The one-way check valve.
One-way check valves are installed between the compressor and the air tanks, and often between the wet tank and the primary/secondary tanks, to ensure that air flows only in one direction (into the tanks) and prevents it from escaping back if there's a problem upstream.
Why the other options are wrong
- A. The brake pedal treadle valve applies air to the brake chambers and doesn't prevent backflow to the compressor/supply.
- B. The governor controls when the compressor pumps air, but doesn't prevent backflow from tanks.
- C. The safety relief valve protects against over-pressurization but doesn't prevent air from leaving the tanks due to a supply line failure.
Air System Check Valves
One-way check valves are crucial components in an air brake system that ensure air flows in only one direction, maintaining pressure in the reservoirs.
- Prevents air from bleeding back to the compressor.
- Maintains tank pressure if supply line fails.
- Essential for dual system integrity.
Memory trick: Check the valve, air won't leave, only receive.