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ABC Wastewater 3- Pumps & Hydraulics
If a pump loses its prime because the suction line has an air pocket, what is the best solution? A. check pump's amperage and be sure pump's strainer is clean B. clean or repair priming unit C. suction piping air bleed off valves should be open D. check external water seal unit - โ โ C. suction piping air bleed off valves should be open What type of pump has little chance of losing its prime but has the disadvantage of having a lack of access for maintenance or repair? A. recessed impeller or vortex pump B. turbine pump C. submersible pump D. positive-displacement pump - โ โ C. submersible pump What type of pump can handle materials that would typically clog or damage the pump's impeller but has the disadvantage of being less efficient? A. recessed impeller or vortex pump B. turbine pump C. submersible pump
D. positive-displacement pump - โ โ A. recessed impeller or vortex pump What type of pump can produce a high head but requires high maintenance if large amounts of solids are being pumped? A. recessed impeller or vortex pump B. turbine pump C. submersible pump D. positive-displacement pump - โ โ B. turbine pump What type of pump adds energy to the fluid flow intermittently? A. recessed impeller or vortex pump B. turbine pump C. submersible pump D. positive-displacement pump - โ โ D. positive-displacement pump Diaphragm pumps do not work very well if they have to lift liquids more than about A. 4 ft B. 8 ft C. 12 ft D. 20 ft - โ โ A. 4 ft Before installing casing wear rings, they should be
A. keep oil or graphite on the shaft B. control water leakage along the pump's shaft C. prevent water leakage from the pump's shaft D. help prevent shaft from warping - โ โ B. control water leakage along the pump's shaft Most pump packing is composed of ______ with lubrication. A. asbestos base, graphite B. flax, polytetrafluoroethylene (PTFE) C. PTFE, inert oil D. aluminum or copper, inert oil - โ โ A. asbestos base, graphite The packing used for medium pressures and temperatures is most likely A. aluminum B. plant fiber C. asbestos D. PTFE - โ โ C. asbestos Packing used in high-speed pumps and temperatures greater than 450ยฐF should be made of A. asbestos B. metal braided with asbestos C. 100%PTFE
D. synthetics - โ โ B. metal braided with asbestos New packing rings should be staggered at A. 45 degrees B. 90 degrees C. 120 degrees D. 180 degrees - โ โ B. 90 degrees Packing is designed to A. add lubricant to the shaft B. expand and deteriorate with normal use C. protect the shaft D. wear and deteriorate with normal use - โ โ D. wear and deteriorate with normal use Packing replacement is usually performed when A. water leakage sprays out of the pump housing B. no further tightening can be done on the packing gland C. the packing gland bolts are exposed by more than 2Yz in. above the nut D. the packing has completely disintegrated - โ โ B. no further tightening can be done on the packing gland Seal water used to cool and flush mechanical seals should originate from an external source for all the following circumstances except:
C. gear coupling D. flexible disk coupling - โ โ A. split coupling Which one of the following statements is false? A. most pumps are self-priming B. bearings can be over lubricated C. fire point is defined as the point at which a lubricant will burn D. oil is used in high rpm conditions while grease is used in low speeds and heavy loads - โ โ A. most pumps are self-priming How often should amperage and voltage tests be performed on three- phase motors? A. monthly B. at least every 3 months C. at least every 6 months D. at least once per year - โ โ B. at least every 3 months The purpose of lubrication is to A. remove heat and reduce friction B. prevent corrosion C. reduce wear D. increase torque - โ โ D. increase torque Grease that is water resistant is made with
A. graphite B. animal fat C. calcium D. potassium phosphate - โ โ C. calcium What is the approximate reduction in oil's "life" for each rise in temperature of 20ยฐF over 140ยฐF? A. 15% B. 33% C. 50% D. 60% - โ โ C. 50% Lubrication used on bearings of line shaft turbines can be A. oil or water B. grease or oil C. lithium or grease D. graphite or grease - โ โ A. oil or water Excessive up thrust on line shaft turbines is caused by A. misalignment of shaft B. pumping too much water C. impeller that is too small or worn
B. radial-flow impeller C. mixed-flow impeller D. vertical-flow impeller - โ โ B. radial-flow impeller The capacity of a centrifugal pump is related to total head A. directly B. indirectly C. linearly D. disproportionately - โ โ A. directly As the total head on a system increases, the volume that a centrifugal pump delivers is reduced A. directly B. indirectly C. proportionately D. disproportionately - โ โ C. proportionately In wastewater treatment, non clogging pumps are usually designed to pass solids that have a diameter of at least A. 3 in. B. 5 in. C. 6 in. D. 8 in. - โ โ A. 3 in.
What type of centrifugal pump is used to ensure that a wet well's pump maintains sufficient prime? A. service water pump B. submersible pump C. dry pit pump D. recirculation pump - โ โ C. dry pit pump Typically, pumps used to return activated sludge, recycle trickling filter effluent, or return digester supernatant would be A. recirculation pumps B. submersible pumps C. service water pumps D. wet well pumps - โ โ A. recirculation pumps Besides providing the enclosure for the impeller, the volute case is also cast and machined to provide a seat for the A. lantern ring B. impeller rings C. mechanical seal D. slinger ring - โ โ B. impeller rings If a centrifugal pump with a single volute is operated less than of its design capacity, an excess radial load will result, causing premature bearing failure.
D. rotary pumps - โ โ B. vertical mounted pumps A type of rigid coupling would be A. chain coupling B. split coupling C. gear coupling D. jaw coupling - โ โ B. split coupling How much will a flexible disk coupling compensate for in angular movement? A. 1 degree B. 2 degrees C. 3.2 degrees D. 3.7 degrees - โ โ B. 2 degrees How much will a flexible disk coupling compensate for in parallel misalignment? A. 1/32 in. B. 1/16 in. C. 1/8 in. D. 1/4 in. - โ โ A. 1/32 in. Hydraulics is the study of A. fluid pressure in pipes or conduits
B. the force of fluids in motion C. the pressure of fluids in motion D. fluids in motion and at rest - โ โ D. fluids in motion and at rest What is it called if the energy supplied to a pump is equal to the energy required for the liquid to be moved to a specific point? A. static head B. pump head C. cut-off head D. total head - โ โ C. cut-off head The arrangement of pumps in series is primarily used to increase the A. flow,usually by 70-80% B. discharge head C. flow but keep discharge head the same D. pump efficiency - โ โ B. discharge head The arrangement of pumps in parallel is typically used A. when head is not sufficient and more flow is required B. to increase discharge head without increasing flow C. to increase flow but keep discharge head the same D. to increase pump efficiency - โ โ A. when head is not sufficient and more flow is required
B. velocity head C. potential energy D. pressure head - โ โ C. potential energy Open impellers are usually used to pump water that contains A. any chemicals except acids B. alkaline chemicals only C. viscous polymers D. large solids - โ โ D. large solids Which type of centrifugal pump can have water enter from two sides (double suction)? A. end suction pump B. split-case pump C. vertical turbine pump D. close coupled pump - โ โ B. split-case pump Which type of impeller is best to use for pumping water with low volumes of solids? A. closed B. open C. semiopen D. radial - โ โ A. closed
What type of pump has the ability to rotate its discharge 360ยฐ? A. vertical pumps B. split-case pump C. end suction pump D. jet pumps - โ โ C. end suction pump A split-case pump has three impellers. What type of multistage pump is this? A. one stage B. two stage C. three stage D. six stage - โ โ B. two stage
- A split-case pump has two equal smaller impellers placed on either side of two equalize large impellers. How many stages does this pump have? A. one stage B. two stages C. four stages D. eight stages - โ โ B. two stages The lowest pressure point in the pump is A. the center of the impeller B. the outermost part of the impeller
A. shear load B. thrust load C. radial load D. stress load - โ โ B. thrust load A load, perpendicular to a pump shaft, applied to a bearing is called A. a shear load B. a thrust load C. a radial load D. axial - โ โ C. a radial load Which one of the following is not a component of a bearing? A. rolling pin B. inner and outer races C. rolling element D. cage - โ โ A. rolling pin All of the following cause bearing failure, but which one is the major cause of bearing failure? A. poor lubrication practices B. contamination C. vibration D. faulty mounting - โ โ A. poor lubrication practices
When removing the volute case at the gasket from a pump, you should use A. hammer and screwdrivers B. chisels C. soft-faced hammer D. screwdrivers or chisels - โ โ C. soft-faced hammer The impeller of a pump is prevented from turning on the shaft by a A. lock nut on threaded shaft B. key C. steel pin D. caliper pin - โ โ B. key How should a pump's shaft be stored when not in use? A. stored vertically, on end B. stored, horizontally in foam or other soft material C. stored in a shaft box and coated with a light oil to prevent corrosion D. stored horizontally in a long box on foam that is saturated with a light oil - โ โ A. stored vertically, on end The purpose of the shaft sleeve is to prevent A. erosion of the shaft B. wear at the stuffing box
