Chapter 18-Compressors

What best describes a direct-drive compressor?

A compressor's crankshaft connected to a motor's drive shaft by a coupling.

Which of the following best describes the compression action in a screw compressor?

A pair helical rotors traps and compresses vapor between the lobes in one rotor and the grooves in the other rotor

What statements are true about Centrifugal Compressors?

As the speed of a centrifugal compressor increases, its efficiency decreases, Centrifugal compressors often have multiple impellers that operate in series

A_______connects the piston to the crankshaft in a reciprocating compressor.

Connecting rod

What is true regarding rotary compressors?

Rotary compressors have low volumetric efficiency, and the blade on stationary blade rotary compressor is mounted in the compressor housing rather than in the rotor.

A reciprocating compressor that has a long piston with an elliptical slot in the bottom of the piston skirt and no connecting rod is called a?

Scotch Yoke Design

What is true regarding scroll compressors?

Scroll compressors operate with continuous suction and discharge, resulting in very smooth compression cycle, In a scroll compressor, vapor is compressed by a series of pistons that travel in a spiral pattern through a fixed scroll

What is a trait of stationary-blade rotary compressors?

The blade is pulled into contact with the rotor by centrifugal force

The primary purpose of a crankcase heater is?

To minimize the amount of liquid refrigerant in the compressor oil

What is not an approved method of cooling compressors?

Using a small relief valve to vent refrigerant to atmosphere for evaporative cooling around the crankcase.