Deck 4

Question 1

What does the compressor do?

Answer 1

Pump refrigerant Vapor and raises refrigerant pressure and temp

Question 2

Reciprocating compressor

Answer 2

Transfer of the direction of force
Up and down of pistons

Question 3

Intake Stroke

Answer 3

Pulled down
Pressure drops
Suction valve opens
Vapor enters cylinder

Question 4

End of Intake Stroke

Answer 4

Piston at bottom
Cylinder pressures equalizes
Intake valve closes

Question 5

Pistons rises

Answer 5

Increases pressure in cylinder
Discharge valve opens

Question 6

Compression Stroke- Piston at top

Answer 6

Pressures equalize, discharge valve closes, discharge Vapor trapped on “clearance volume”

Question 7

Vapor must re-expand before

Answer 7

Suction valve can open

Question 8

Downwards Stroke

Answer 8

Suction Vapor pulled in, pressures equalize, ready for compression

Question 9

In each cycle there is

Answer 9

Suction, compression, discharge

Question 10

Hermetic Compressor

Answer 10

Airtight container

Welded steel shell

Internal springs

Suction cooled motor

Question 11

Tare weight

Answer 11

Weight of tank when empty

Question 12

Water capacity

Answer 12

Amount of water it can hold in pounds

Question 13

Nominal tank sizes 25 and 50 lbs

Answer 13

80%

Question 14

Reinspect

Answer 14

5 years

Question 15

Tanks have

Answer 15

One valable for liquid and another for gas

Question 16

Remove Vapor

Answer 16

Condense into liquid and discharge into recovery tank

Question 17

Pushing out liquid first saves time

Answer 17

Vapor recovery on large systems is slow

Question 18

A chilled tank

Answer 18

Speeds liquid recovery

Question 19

Louis must be changed to

Answer 19

Vapor to recover

Question 20

An orifice in the inlet

Answer 20

Vaporizes the liquid

Question 21

Appointment does

Answer 21

0.6 pounds per minute

6 pounds per minute liquid recovery

16 pounds per minute of push pull recovery

Question 22

Only recover

Answer 22

CFC HCFC AND HFC

Question 23

Compression ratio

Answer 23

High side divided by low

Absolute discharge divided by absolute suction

Question 24

What are compression ratios used for?

Answer 24

To compare pumping conditions for compressor. Higher than 12 to one is bad because it may become overheated.

Question 25

The main types of compressors are…

Answer 25

Reciprocating screw rotary scroll in centrifugal

Question 26

Reciprocating

Answer 26

Is used in medium size commercial refrigeration system

Question 27

Screw is

Answer 27

In industrial systems

Question 28

Rotary reciprocating and centrifugal

Answer 28

Are used in residential and light commercial air-conditioning 

Question 29

Electrical

Answer 29

Motor overlaid and terminals

Question 30

Mechanical

Answer 30

Crankshaft pistons valves and lead

Question 31

Lubrication

Answer 31

There must be oil film on every surface

Question 32

Connecting rods

Answer 32

Connect shaft to the piston

Question 33

Too high oil

Answer 33

Can’t see top of oil

Question 34

Too low oil

Answer 34

Can’t se any oil

Question 35

Good oil level

Answer 35

Anywhere in sight glass per Copeland

Question 36

Air cooled compressor

Answer 36

Motor is pressed right into housing: external air flow cools compressor motor

Question 37

Suction and discharge service valves

Answer 37

Next to cylinders

Question 38

Valve plate

Answer 38

Holds reeds in place

Question 39

The head

Answer 39

Holds valve plate in place Separates suction and discharge Vapor

Question 40

Copeland design is more efficient

Answer 40

Due to discharge valve design

Question 41

Discharge valve looks like disc

Answer 41

Less clearance volume, less re expansion more efficient

Question 42

For mid seat position: Opens service port (gauge port)

Answer 42

For reading system pressure, also for charging recovery and evacuation