Which type of valve is specifically designed to prevent the backflow of water in a pipeline when a pump stops or a pipe bursts?
- ASluice Valve
- BReflux ValveCorrect
- CAir Relief Valve
- DScour Valve
Solution
Concept
Reflux valve backflow prevention
Formula
NONE
Step-by-step solution
1. Pipeline check valves protect pumps and pipes against reverse flow. 2. A reflux valve contains a hinged or spring-loaded disk that opens with forward flow. 3. When flow ceases or reverses, the disk closes against its seat automatically. 4. Therefore, reflux valves prevent water backflow. Answer: B
Explanation
A reflux valve (also designated as a check valve or non-return valve) is an automatic mechanical valve designed to permit fluid flow in only one direction. When downstream pressure exceeds upstream pressure upon pump shutoff or downstream pipe failure, the valve disk closes instantly to prevent hazardous reverse flow and water hammer.
Why the other options are wrong
A) Sluice valves provide manual flow control and pipeline isolation. C) Air relief valves release accumulated air pockets at high pipeline summits. D) Scour valves flush out silt and sediment deposited in valley depressions.
Shortcut
Reflux valve = Check valve = Non-return valve (prevents backflow).
Common mistake
Confusing reflux valve with sluice valve used for isolating pipe sections.
Correct answer: B) Reflux Valve