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10 Cards in this Set

  • Front
  • Back
This occurs when the temperature of a strong but still unsaturated solution is lowered so far that its salt concentration exceeds the maximum concentration possible at the lower temperature.
a) Ionization
b) Dissociation
c) Crystallization
d) Vapourization
e) Neutralization
C

When the temperature of a solution increases, which of the following statements is true?
a) The vapour pressure is high
b) Less water molecules leave the solution
c) The solubility of the salt decreases
d) The concentration decreases
e) The equilibrium constant decreases
A

The concentration of Lithium Bromide in an absorption refrigerating system will change during which of the following steps?
a) Going through the expansion valve
b) Going through the suction valve
c) Cooling through the heat exchanger
d) Absorbing water vapour in the absorber
e) None of the above
D

Concentration of the Lithium Bromide can be most easily controlled by which of the following means?
a) Controlling the volume of water sprayed into the absorber.
b) Controlling the temperature in the cooling tower.
c) Controlling the amount of weak Lithium Bromide pumped into the generator.
d) Controlling the pressure in the vacuum between the evaporator and the absorber.
e) Controlling the temperature in the generator.
E

Which of the following is NOT a result of having noncondensable gases in the absorption systems?
a) Corrosion
b) Oxidation of Lithium Bromide
c) Lower than normal temperatures of the chilled water leaving the evaporator
d) Reduction in capacity of the system
e) Crystallization in the heat exchanger
C

Which of the following are elements of a mechanical purging system?
i) purge pickup tube
ii) purge chamber
iii) manual shutoff valve
iv) safety solenoid valve
v) oil trap
vi) vacuum pump
a) i and ii only
b) i, ii, and v only
c) iv and vi only
d) i, iii, and v only
e) all of the elements
E

Which of the following is not a step in the seasonal prestart service?
a) clean all cooling and chilled water strainers
b) add water treatment chemicals
c) turn on energy sources
d) check the purge pump
e) check the magnetic strainers
C

During seasonal startup, when should the purge pump be started?
a) Simultaneously with the absorption unit
b) One half hour before the absorption unit is started
c) At least 24 hours after the compressor is started
d) About one half hour after the absorption unit is started
e) Only when noncondensables are detected in the system
D

When shutting down the refrigeration system for a weekend or less which of the following is a correct shutdown procedure?
a) Drain the cooling water circuit
b) Close the manual steam or hot water supply valve
c) Service the purge pump
d) Open all disconnect switches
e) Turn off the air supply to the pneumatic control system
B

If there is a crystallization upon shutdown a possible corrective action is to
a) add octyl alcohol charge
b) purge the system
c) adjust cooling tower control
d) check pump operation
e) reduce steam pressure
D