Terms And Scientific Principles Applied To Cryogenic Equipment

Question 1

Atmospheric Pressure

Answer 1

• Pressure exerted by the weight of the weight of the atmosphere
• Standard atmospheric pressure 14.696 PSIA
• Equivalent to 29.92 inches of mercury at sea level

Question 2

Fahrenheit

Answer 2

• 32 degrees Fahrenheit is the freezing point of the water

- 212 degrees Fahrenheit is the boiling point of the water

Question 3

Rankine

Answer 3

• Thermometer scale based on absolute zero of the Fahrenheit Scale
• 492 degrees Rankine freezing point of water
• 672 degrees Rankine boiling point of water
• also known as Fahrenheit Absolute Scale

Question 4

Kelvin

Answer 4

• thermometer scale based on absolute zero of the Celsius scale
• 273 degrees Kelvin freezing point of water
• 373 degrees Kelvin boiling point of water
• also known as International-Practical Scale

Question 5

British Thermal Unit (BTU)

Answer 5

The amount of heat required to produce a temperature rise of 1 degree Fahrenheit in one pound of water

Question 6

Refrigeration Ton

Answer 6

Removal of heat at the rate of 288,000 BTU’s in 24hrs or 12,000 BTU’s in one hour

Question 7

Latent Heat

Answer 7

Heat that is given of or absorbed by a substance while it is changing state without changing temperatures

Question 8

Latent Heat of Vaporization

Answer 8

Change state from a liquid to vapor without a change in temperatures

Question 9

Latent Heat of Condensation

Answer 9

Change of state from vapor to a liquid without a change in temperatures

Question 10

Latent Heat of Fusion

Answer 10

Change the state from a liquid to a solid (freezing) or from a solid to a liquid (melting)

Question 11

Saturation Temperature

Answer 11

The temperatures at which a liquid boils under a given pressure

Question 12

Conduction

Answer 12

A transfer of heat from one body to the another when the two bodies are in physical contact

Question 13

Convection

Answer 13

The transfer of heat by the circulation of a liquid or gas such as air

Question 14

Radiation

Answer 14

The transfer of heat in the form of waves similar to light and radio waves, without physical contact between the emitting and the receiving regions

Question 15

Relative Humidity

Answer 15

The ratio of the weight of water vapor in a quantity of air to the weight of water vapor which that quantity of air would hold if saturated at the existing temperature

Question 16

Velocity

Answer 16

Speed in definite direction

Question 17

Cryogenics

Answer 17

Temperatures below -150 degrees Fahrenheit (-101 degrees Celsius)

Question 18

Fractional Distillation

Answer 18

• The process used to separate the components of a substance through differences in physical or chemical properties
• In cryogenics, liquefying air and then separating the resulting distillate into its individual components due to the fact that each component has its own specific boiling point

Question 19

Reflux

Answer 19

The process in which liquid moves down a distillation column and comes into close contact with vapors rising up the column, thereby stripping them (the vapors) of their less volatile components

Question 20

Cavitation

Answer 20

Formation of a gas pocket in the inlet chamber of a cryogenic pump resulting when the temperature of the pumped liquid rises above its boiling point

Question 21

Lined Cycle

Answer 21

• A method of liquefying air, employed in all shipboard air separation plants that use Joules-Thompson expansion, heat exchange, and auxiliary refrigeration
• High Pressure Cycle means the same thing as Linde Cycle

Question 22

Joule-Thompson Expansion

Answer 22

Expansion of high pressure gas through a valve or orifice to reduce its temperature, as in the Linde Cycle

Question 23

Claude Cycle

Answer 23

A method of liquefying air involving compression of the air and expansion portion of it through an expansion engine

Question 24

Absorbent

Answer 24

A material that has the ability to soak up or extract certain substances from a liquid or a gas with which air is in contact, without causing change to the fluid passing around the material

Question 25

Adsorbent

Answer 25

A material that has the ability to cause molecules of gases and liquids to adhere to its external surfaces, possibly causing a physical or chemical change in the fluid passing around the material

Question 26

Standard Air

Answer 26

- Air at 68 degrees Fahrenheit - 14.7 PSIA - a relative humidity of 36 % - weight density of 0.0075 pounds per cubic foot

Question 27

Oxygen (O2) Gaseous

Answer 27

- Colorless and odorless - it’s not flammable - supports and rapidly accelerated the combustion of all flammable material

Question 28

Oxygen (O2) Liquid

Answer 28

- Pale blue, transparent fluid - (-297 degrees Fahrenheit) boiling point - 1.14 specific gravity at atmospheric pressure - 1 gallon liquid oxygen weighs 9.53lbs

Question 29

Nitrogen (N2) Gaseous

Answer 29

An inert has, slightly lighter than air, it does not form flammable or explosive mixture with air or oxygen, nor will it support combustion or respiration

Question 30

Nitrogen (N2) Liquid

Answer 30

- A colorless, transparent fluid - (-320 degrees Fahrenheit) boiling point - 0.808 specific gravity at one atmosphere absolute (14.7 lbs/in2)

Question 31

Purity

Answer 31

The percent by volume of the major constituent in a gas

Question 32

Boyle’s Law

Answer 32

The volume of any dry gas varies inversely with the applied pressure, provided the temperature remains constant

Question 33

Charles’ Law

Answer 33

The volume of any dry gas varies directly with the applied temperature, provided the pressure remains constant

Question 34

General Gas Law

Answer 34

By combining Boyle’s Law and Charles’ Law, a single expression can be derived which includes all the information contained in both

Question 35

Dalton’s Law of Partial Pressures

Answer 35

The pressure exerted on the inner walls of a vessel is the sum of the pressure that each gas would exert if it were present alone

Question 36

Bourbon Tube Pressure Gauge

Answer 36

A thin walled tube bent into the shape of a “C”, which tends to straighten out when pressure is exerted

Question 37

3 Methods of Refrigeration

Answer 37

- Mechanical Refrigeration - Joules-Thompson Refrigeration Effect - Claude Cycle Refrigeration Effect

Question 38

Mechanical Refrigeration

Answer 38

A mechanical system or apparatus that transfers heat from one substance to another

Question 39

Joules-Thompson Refrigeration Effect

Answer 39

Expansion of a high pressure gas through an expansion valve to reduce temperature

Question 40

Claude Cycle Refrigeration Effect

Answer 40

A method of liquefying air by compressing the air and then expanding it through an expansion engine