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Flashcards in Refrigeration/ Air Conditioning Systems Deck (42):
1

what is meant by the term pumping down?

removal of refrigerant before maintenance on a reciprocating system which is to be opened to the atmosphere

2

what is meant by the term pumping when dealing with refrigerant?

to release of air and non condensable gases from a system

3

what is meant by the term slugging?

the liquid refrigerant returning o the compressor causing noisy valves

4

what does the term low side refer to?

the part of system lying between the expansion valve and the suction valve of the compressor

5

the term frosting back refers to what?

the appearance of frost on the suction line extending as far back as the compressor

6

what NSTM would you use when researching refrigeration systems?

NSTM 516

7

what type of refrigeration compressors are used onboard naval ships?

reciprocating and centrifugal

8

the capacity of a reciprocating compressor plant is expressed in?

tons of refrigerant

9

all content high speed compressors operate at what RPM?

1750 rpm

10

what type of lube oil system would be found on a high speed compressor?

force feed lubrication

11

what is the purpose of a thermal expansion valves?

control the quantity of refrigerant that is admitted to the cooling coil and to reduce the pressure of the refrigerant

12

the load on the vapor compression air conditioning plant is determined by what?

the espied chill water temperature

13

two basic types of chilled water air conditioning systems are now in use, they are?

vapor compression and lithium bromide absorption

14

what purpose does the refrigerant compressor receiver serve?

acts as a surge tank and a temporary storage space for the liquid refrigeration

15

where is the dehydrator located in the refrigerant compressor system?

in the liquid refrigerant line between the TXV and the receiver

16

the dehydrator contains what type of drying agent?

silica gel or activated allumina

17

a pink indication on moisture indicator means?

excessive moisture has damaged the indicator, it must be replaced

18

proper refrigerant temperature of a space is maintained by what?

a solenoid valve and its related thermostatic switch

19

what automatically stops a refrigerant compressor when a failure of circulating water supply occurs?

water failure switch

20

the refrigerant liquid strainer is designed to protect what?

the solenoid valves and TXV

21

refrigerant piping is made of what material?

ACR seamless copper

22

nearly all hand operated valves in large refrigeration systems are packless for what reason?

to facilitate maintenance of the valves without valve removal

23

how are refrigerant leaks found?

by use of an electronic leak detector or by the soapsuds test

24

when properly tightened a V-belt can be depressed how far?

1/2 to 3/4 by the pressure of one finger at a point midway between the flywheel and the motor pulleys

25

is it allowable to use belt designs on a V belt?

Never

26

before handling refrigerant bottles you should read what NSTM?

NSTM 670

27

refrigerant cylinders must always be stowed in what manner?

in a cool, dry place, in an upright position

28

never allow a refrigerant cylinder to reach what temperature?

130 deg F

29

cylinder valves must always be protected by what?

cylinder tops

30

what must be done to a refrigerant cylinder when refrigerant has been discharged?

immediately weigh the cylinder and record the weight

31

refrigerants are considered to be deadly due to their composition of what?

halocarbons

32

is it ever allowable to mix refrigerant gases?

never

33

when measuring a certain space temperature, what two temperature readings determine air conditioning effectiveness?

wet bulb and dry bulb thermometer readings

34

dry bulb thermometer is a measurement of what?

sensible heat

35

what approval is required before using self contained air conditioners?

NAVSEA

36

what type of heat exchange is used in the lithium bromide absorption units?

regenerative type

37

what manual contains safety precaution for forces afloat when dealing with refrigerants and air conditioners?

OPNAVINST 5100.19 SERIES

38

what is the latent heat of fushion?

144 BTU's

39

the most commonly used refrigeration systems used aboard ship is?

vapor compression type with reciprocating compressors

40

what purpose does the compressor in a refrigeration unit serve?

acts a pump

41

heat is absorbed by the refrigeration stored normally in what component?

the refrigerant evaporator

42

the float valves in a centrifugal refrigeration plant serves what purpose?

releases the refrigerant to the chiller