Pulp and Paper Questions and Answers for Campus interviews on “Positive Displacement Pumps”.
1. Positive displacement pumps actually enclose the fluid to be moved through the system.
a) True
b) False
Answer: a
Clarification: The pressure and volume at which the liquid could be discharged depend only upon the mechanical strength and size of the properly operating pump and the energy supplied to the pump any neglecting leakage.
2. _________ valves are utilized to prevent damage to the system or build-up of high, dangerous pressures.
a) Globe
b) Pressure relief
c) Needle
d) Gate
Answer: b
Clarification: It is a type of valve utilized to control or limit the pressure in a system or vessel which could build up for a process upset, instrument or equipment failure, or fire. The pressure is relieved by allowing the pressurized fluid to flow from an additional passage out of the system.
3. Reciprocating __________ utilize a piston moving back and forth in a cylinder. Nearly 2 check valves for the input and output at one end of the cylinder allow one way flow; this gives a pulsed output.
a) Valves
b) Pumps
c) Pits
d) Spots
Answer: b
Clarification: A reciprocating pump is a class of positive-displacement pumps which consists the piston pump, plunger pump and diaphragm pump. It is often utilized where a relatively small quantity of liquid is to be handled and where delivery pressure is quite large.
4. ___________ cylinders could be utilized to give a continuous output as in pumps for high performance liquid chromatography, or one cylinder could be made to deliver with either stroke.
a) One
b) Two
c) Three
d) Four
Answer: b
Clarification: High-performance liquid chromatography earlier referred to as high-pressure liquid chromatography, is a technique in analytical chemistry utilized to separate, identify, and quantify each component in a mixture.
5. In diaphragm pump the piston assembly is replaced by a diaphragm and housing; these pumps are often powered by ________ and occur as double diaphragm pumps.
a) Compressed air
b) Saturated liquid
c) Distilled water
d) Vacuum
Answer: a
Clarification: It’s a positive displacement pump that utilizes a combination of the reciprocating action of a rubber, thermoplastic and suitable valves on either side of the diaphragm to pump a fluid.
6. A pair of gears with many teeth; external to the gear and known as ________ in gear pumps or a few lobes in lobe pumps.
a) Internal gear pump
b) External gear pump
c) Lobe pumps
d) Tubing pumps
Answer: b
Clarification: External gear pumps could come in 1 or 2 gears, the pump configurations with spur, helical, and herringbone gears. Helical and herringbone gears generally offer a smoother flow as compared to spur gears, although all gear types are relatively smooth.
7. ________ utilize a gear within a gear design; internal means the teeth of 1 gear are on the inside, projecting inward.
a) Internal gear pump
b) External gear pump
c) Lobe pumps
d) Pencil pumps
Answer: a
Clarification: Internal gear pumps are very versatile. They are often utilized on thin liquids such as solvents and fuel oil, they are good at efficiently pumping thick liquid such as asphalt, chocolate, and adhesives.
8. ________ pumps are useful for pumping viscous liquids or slurries, but highly viscous liquids would require relatively large, slow moving pumps to keep N.P.S.H.A greater than N.P.S.H.R.
a) Gear
b) Teeth
c) Tubing
d) Lobe
Answer: a
Clarification: Gear pumps are positive displacement, meaning they pump a const. amount of fluid for each revolution. Some gear pumps are manufactured to function as either a motor or a pump.
9. The ________ pump utilizes a tube in the shape of a semi-circle with 2 or more pinching rollers on the outer edge of a wheel that rotates on the inside of the semi-circle.
a) Gear
b) Teeth
c) Tubing
d) Lobe
Answer: c
Clarification: These are classified as high volume, heavy duty pumps. Maximum production could be expected with this type in relation to the size of tubing. Just because of the large plunger diameter, the fluid load would be greater than with an insert pump.
10. Rotary vane pumps are also utilized for vacuum pumps.
a) True
b) False
Answer: a
Clarification: It’s a positive-displacement pump which consists of vanes which are mounted to a rotor that rotates inside of a cavity. In some cases these vanes could have variable length and be tensioned to maintain contact with the walls as the pump rotates.
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