Which valve uses a flexible sleeve that is pinched to stop flow?

• A. Gate valve
• B. Diaphragm valve
• C. Globe valve
• D. Pinch valve

Answer: (D)

Flow is stopped by pinching a flexible sleeve, not by moving a solid gate or disk into the flow path. In a pinch valve, the line contains a flexible tube or sleeve. External pinchers or rollers squeeze parts of that sleeve to collapse it and seal the passage, halting flow. Releasing the pinchers lets the sleeve spring back to its round shape and flow resumes. This contrasts with other valves: a gate valve uses a rigid gate that slides into the bore to block flow; a diaphragm valve seals by flexing a diaphragm against a seating surface; and a globe valve throttles or stops flow with a movable disk that sits against a seat. Pinch valves are especially good for slurries or fluids with solids because the flow path remains a smooth tube inside the sleeve and the sealing surface is outside the fluid, reducing clogging and wear on internal parts.