REF UNIT 28

Question 1

(28.2) How much of the atmosphere is nitrogen?

Answer 1

78%

Question 2

(28.2) what is the boiling temperature of CO2 and nitrogen?

Answer 2

CO2: -109°F
Nitrogen: -320°F

Question 3

(28.2) define eutectic solution

Answer 3

brine that has the ability to change states at multiple temperatures. it’s used in cold plates.

Question 4

(28.2) what is a nose-mount and under-belly unit?

Answer 4

the two locations a condenser and compressor are housed in large trucks

Question 5

(28.2) what is used to regulate the speed of an engine-driven compressor?

Answer 5

a governor

Question 6

(28.2) how are truck bodies usually insulated?

Answer 6

foam insulation sprayed and wallboard fastened to the foam.

Question 7

(28.2) what is the system called where a refrigerated truck is carried on railroad?

Answer 7

piggyback

Question 8

(28.5) what’s are cascade systems for?

Answer 8

systems with operating temperatures to about -160°F

Question 9

(28.5) how is cascade refrigeration accomplished?

Answer 9

each stage of compression uses it’s own cycle

Question 10

(28.6) define flash-freezing

Answer 10

the method of freezing something rapidly to preserve it well.

Question 11

(28.6) define blast freezing

Answer 11

blasting product with cold air at high velocity to freeze rapidly.

Question 12

(28.7) T or F: on ships, sea water may be used in defrost.

Answer 12

True