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Unit 23 Compressors Quiz
Terms in this set (30)
The compressor in the mechanical refrigeration system is much like the heart in the human body.
At a constant RPM, a compressor is a constant displacement device and its capacity is variable.
At a constant RPM, a compressor is a constant displacement device and its capacity is constant.
The most common method(s) of capacity control for rotary compressors are motor speed control and on-off cycling.
The pattern of gas movement through a scroll compressor is from the center toward the perimeter.
The suction and discharge valves in a reciprocating compressor open and close depending on the difference in pressure across them.
Scroll compressors are becoming popular because they can handle liquid flood-back without compressor damage.
The scroll compressor is one type of reciprocating compressor.
Rotary compressors have pistons that rotate inside the cylinders.
Rotary compressors have no "clearance volume".
The sight glass on a semi-hermetic compressor is used to allow light to enter the crankcase to keep the oil warm.
The hermetic reciprocating compressor motor is essentially made of the same materials as an open type compressor motor.
A bolted together motor-compressor assembly is sometimes referred to as a semi-hermetic type.
The higher the rpm of a compressor, the higher the pumping efficiency.
All but which one of these things happens as a direct result of the compressor doing its work?
the air is adequately circulated in the conditioned space.
What is the compression ratio at these conditions?
Discharge pressure: 282.3
Evaporator pressure: 49.3
Condenser pressure: 277.3
Suction pressure: 51.3
The piston of a reciprocating compressor must make ___ stroke(s) to complete one cycle of refrigerant compression.
The reciprocating compressor has a built-in problem with inefficiency which results from:
its clearance volume.
If the compression ratio of a system with a reciprocating compressor decreases, the amount of refrigerant pumped by the compressor ___
If the suction valve in a reciprocating compressor is leaking slightly, the ____
cooling capacity will be reduced & compressor can overheat.
The clearance volume of a compressor ____
remains the same as the compression ration decreases.
What could happen if a semi-hermetic compressor is operated with the suction service valve back-seated and the discharge valve front-seated?
the head of the compressor may blow off.
Liquid entering the compression chamber of a reciprocating compressor can lead to ___
damaged valves & damaged piston rings
Mos of the heat energy in the suction vapor entering the compressor is ___
The temperature of the compressed gas leaving the compressor can best be described as ___
The screw-type compressor is used primarily in ___
large industrial refrigeration and air-conditioning systems.
Rotary compressors are used primarily in __
The clearance volume of a compressor cylinder is the ___
volume of the space between the bottom of the valve plate and the top of the piston at top dead-center.
The discus valve design is more efficient than a flapper valve design because ___
it allows a compressor design with less clearance volume.
Compressors are not designed to compress liquids pumps already exist for that purpose.
Organizations have divided the responsibility for managing the flow of materials and services among
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