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10 Cards in this Set
- Front
- Back
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A two cylinder recriprocating compressor runs at 480rpm and has a 0.004 m2 sectional area of a cylinder, and a stroke of 8cm. calculate the volume compressed per hour a) 12.81 m3/hr b) 18.43 m3/hr c) 26.45 m3/hr d) 30.72 m3/hr e) 63.26 m3/hr |
b) 18.43 m3/hr |
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In a refrigeration system , the purpose of the compressor is to a) establish two pressure levels b) reject the heat from the system c) absorb heat into the system d) regulate the flow of the refrigerant e) heat the refrigerant |
a) establish two pressure levels |
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A typical sationary crankshaft seal consisting of a metallic bellows soldered at one end to a ring (seal nose) which bears either against a shoulder on the shaft or against a seal ring on the shaft is called a a) packing gland seal b) diaphragm seal c) bellows seal d) rotating mechanical seal e) setscrew seal |
c) bellows seal |
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Which of the following compressor types uses impellers to draw in vapor? a) centrifugal b) helical screw c) reciprocating d) sliding vane e) stationary single blade rotary |
a) centrifugal |
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In rotary mechanical seals the sealing ring is held in position by a) a nut, bolt, and washer b) centrifugal force c) oil suction d) high pressure refrigerant e) a spring |
e) a spring |
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Piston displacement is defined as a) the distance along which the piston travels b) the cylinder bore c) the volume of refrigerant that can be circulated through all the cylinders per unit of time d) piston stroke length e) the revolutions per minute of the compressor motor |
c) the volume of refrigerant that can be circulated through all the cylinders per unit of time |
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Which one of the following is not true a) it is possible that liquid refrigerant enters the compressor b) compressor bearings are usually from sleeve and shell type c) larger compressors are equipped with the eccentric type crankshaft d) on a semi-hermetic compressor the end plates can be moved for servicing e) compressors may raise the temperature of the refrigerant |
c) larger compressors are equipped with the eccentric type crankshaft |
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Which of the following is not a function of the compressor in a refrigeration system? a) draw low pressure refrigerant out of the evaporator b) draw low temperature refrigerant out of the evaporator c) lower the temperature of the refrigerant d) maintain suffieciently low pressure in the evaporator e) raise the pressure of the refrigerant |
c) lower the temperature of the refrigerant |
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Which of the following is not true? a) in a stationary single blade design compressure its discharge port may be equipped with a reed valve b) in a helical rotor compressor the mating screws intermesh in one common cylinder casing c) the screw type compressors can run at very high speed d) the screw compressors are positive displacement e) the direction of rotation of rotary compressors are critical |
b) in a helical rotor compressor the mating screws intermesh in one common cylinder casing |
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Which of the following is the compressor responsible for doing. 1 - maintains a high pressure in the condenser 2 - maintains a low pressure in the evaporator 3 - raises the pressure of the refrigerant a) 1 only b) both 1 and 3 c) both 2 and 3 d) 3 only e) 1, 2, and 3 |
e) 1, 2, and 3 |
