1.What is the function of a butterfly valve?
a) On/ off control
b) Flow regulation
c) Pressure control
d) Hydraulic control
Explanation: Butterfly valve is used for flow regulation in large diameter pipes. Spool valve is used for hydraulic control. Ball valve is used for on/ off control of pipes without pressure drop.
2. Which of the following valves is better for on/ off control?
a) Ball valve
b) Butterfly valve
c) Plug valve
d) Knife valve
Explanation: Butterfly valve is for flow regulation. Plug valve involves pressure drop during on/ off control. Ball valve involves on/ off control without pressure drop. It has an ideal quick shut-off since a 90˚ turn offers complete shut-off angle.
3. Which of the following valves are used in high duty cycle applications?
a) Check valve
b) Clapper valve
c) Ceramic disc valve
d) Choke valve
Explanation: Check valves are used where one directional flow is required. In clapper valves, two hose are used instead of one. Ceramic disc valves are used in heavy duty cycle applications or on abrasive fluids.
4. Check valve is also called as _________
a) Non-return valve
b) Gate valve
c) Knife valve
d) Choke valve
Explanation: Check valve is also called as non-return valve because it allows flow in just one direction. Gate valve is used for on/ off control with low pressure drop. Knife valve is similar to gate valve.
5. What is the purpose of piston valve?
a) Regulate fluids
b) Regulate fluids carrying suspended solids
c) Regulates flow
d) Regulates pressure
Explanation: Piston valves are used to regulate fluids carrying solid particles in suspension. Spool valves are used for hydraulic control. Needle valves are used for accurate flow control
6.Poppet valves are used in piston engines.
a) True
b) False
Explanation: Poppet valves are a type oh valves that are used in piston engines. Poppet valves are used to regulate the fuel mixture intake and exhaust. Thermal expansion valves are used in refrigerator and air conditioning systems.
7. Diaphragm valves are used to control flow by a movement of a diaphragm.
a) True
b) False
Explanation: Diaphragm valves are used to control flow by a movement a diaphragm. Upstream pressure, downstream pressure, or an external source can be used to change the position of the diaphragm.
8. What is the other name for the plug valve?
a) Needle valve
b) Slim valve
c) Poppet valve
d) Spool valve
Explanation: Plug valve is also called as slim valve and is used for on/ off control but with little pressure drop. Needle valve is used for accurate flow. Poppet valve is commonly used in piston engines.
9. What is the purpose of pinch valve/
a) Hydraulic control
b) Slurry flow regulation
c) Flow control
d) Regulate fluids
Explanation: Pinch valve is used for slurry flow regulation and control. The piston valve is used for regulating fluids that carry solids in suspension. Spool valves are used for hydraulic control.
10. In globe valves, the flow rate control is determined by _______
a) Size of the opening
b) Lift of the valve plug
c) Pressure difference
d) Gravity
Explanation: Size of the opening plays a major role in controlling the flow rate but in the globe valves, the flow rate is controlled by the lift of the valve plug and not by the size of the opening in the valve seat.