Power Engineering 4th Class unit B 2 chapter 2 Exam Questions And Answers

If a stuffing box is to prevent the ingress of air, it is equipped with: Choose one answer. a. A vacuum breaker b. A seal cage c. A bushing d. A thrust collar e. An anti air siphon - ANSb Pump priming is: Choose one answer. a. Done to centrifugal pumps with positive suction head b. Done with the suction valve open c. Filling the pump with gas d. Done with the suction and discharge valve closed e. When the pump is partially filled with vapour - ANSb Proper priming and venting of a pump is important, especially if: Choose one answer. a. The medium being pumped is high temperature b. The medium being pumped contains suspended solids c. Oil or other low flash point lubricant is being pumped d. A mechanical seal is used e. The pump has a stuffing box and lantern ring - ANSd New pump packing should be installed: Choose one answer. a. Tight enough to stop leakage b. Loose enough to allow leakage for lubrication c. Every shut down d. Every year e. Every time prior to start up - ANSb Priming of a centrifugal pump refers to: Choose one answer. a. Removal of liquid from the pump b. Filling the pump casing with liquid and removing the air c. Lifting the pump d. Closing the vent on the pump casing e. Starting the pump driver - ANSb Before you start up a centrifugal pump you should: Choose one answer. a. Blow off the liquid from the housing b. Close the water to the lantern rings c. Be sure that the pump is primed with liquid d. Close the suction and discharge valves e. Change the lube oil - ANSc Strainers may be found: Choose one answer. a. On the suction side of the pump b. On the discharge side of the pump c. Inside the pump d. On the air vent discharge of the pump e. In the impeller eye of the pump - ANSa The purpose of shaft sealing on a pump is to: Choose one answer. a. Keep air in the pump b. Keep the packing gland cool c. Reduce fluids from leaking along the pump shaft d. Prevent lubricating oil from leaving the pump e. Protect the seal - ANSc A mechanical pump seal: Choose one answer. a. Will have a substantial amount of leakage b. Will cause more wear on the shaft than a packing seal c. Is used for high pressure service d. Does not need cooling e. Is used in reciprocating pump service - ANSc Flexible couplings will compensate for: Choose one answer. a. Overheating of packing b. Minor shaft misalignment c. Bearing failure d. Shaft eccentricity due to a badly bent shaft e. Impeller imbalance - ANSb Wear rings in centrifugal pumps: Choose one answer. a. Are non-replaceable. b. Are installed on impellers c. Protect the shaft from wear. d. Compensate for misalignment of the impeller e. Are only found on high pressure pumps - ANSb What size of packing would you use to repack a pump gland having a stuffing box bore of 8.6 cm and a pump shaft diameter of 6.7 cm? Choose one answer. a. 0.5 cm b. 1.9 cm c. 0.675 cm d. 1.6 cm e. 0.95 cm - ANSe The main advantage of a pump using a mechanical seal is: Choose one answer. a. Lower first cost b. Less maintenance c. Less lubrication d. Ease of repair e. Increases discharge pressure - ANSb The seal cage on the shaft of a centrifugal pump: Choose one answer. a. Holds the shaft packing against the shoulder of the stuffing box b. Assists in reducing shaft vibration c. Distributes sealing fluid to the seal faces d. Prevents fluid from leaking out of the pump casing e. Reduces suction pressure drop - ANSc Before starting a pump, check Choose one answer. a. That the packing is drip free b. That the area around the pump is cool and dry c. That the suction and discharge valves are in their proper positions. d. That the lantern ringturns freely e. The bearing temperatures. - ANSc