3B2 Ch 11 Flashcards
How can moisture in refrigeration systems be removed?
Select one:
a.
Purging
b.
Heating the refrigerant
c.
Making the oil more absorbent
d.
Using a dehydration device or filter/dryer
e.
Blowing down the system
d.
Using a dehydration device or filter/dryer
The liquid charging valve is usually connected to a line that is located where?
Select one:
a.
Between the liquid shut-off valve and the expansion valve
b.
Between the king valve and the condenser
c.
At the compressor discharge line
d.
Between the purge valve and condenser
e.
Between the purge valve and the expansion valve
a.
Between the liquid shut-off valve and the expansion valve
What controls the automatic expansion valve?
Select one:
a.
A transmitter
b.
The evaporator pressure
c.
Capillary action
d.
The refrigerant level
e.
The king valve
b.
The evaporator pressure
Why is a high vacuum maintained before charging a refrigeration system?
Select one:
a.
To draw in atmospheric air
b.
To prevent an explosion
c.
To condense the moisture to be removed
d.
To prevent condensate from evaporating
e.
To evaporate moisture so it can be removed in vapour form
e.
To evaporate moisture so it can be removed in vapour form
The emergency discharge line on refrigeration systems must __________.
Select one:
a.
Be connected directly to the top of the receiver or other vessel used for storing the refrigerant
b.
Be connected to the compressor
c.
Have two valves connected to charging drum
d.
Be connected directly to the top of the condenser and the compressor
e.
Have two return bends in the piping
a.
Be connected directly to the top of the receiver or other vessel used for storing the refrigerant
B2C11Q10 Which of the following instructions is NOT required to be posted near a refrigerant compressor for a system capacity exceeding 125 kW?
Select one:
a.
Design pressure of the system or the set point of the pressure relief valves
b.
Instructions for shutting down the system
c.
Telephone number of first response organization
d.
Name, address, and telephone numbers for obtaining service
e.
Name, address, and telephone number of nearest regulatory or jurisdictional authority
a.
Design pressure of the system or the set point of the pressure relief valves
What is one disadvantage of a low-side float control?
Select one:
a.
Liquid slugs could be carried over to the compressor
b.
The level gets too high in the receiver
c.
The level in the receiver becomes very difficult to control
d.
The control makes it difficult to install a charging valve
e.
The control provides unstable regulation
e.
The control provides unstable regulation
What is the most efficient method of condenser cooling?
Select one:
a.
Air cooling
b.
Water cooling
c.
Latent heat cooling
d.
Diffusion cooling
e.
Cooling by another refrigeration unit
b.
Water cooling
Where should the emergency discharge valve be installed?
Select one:
a.
Within reach of the receiver
b.
In a glass fronted box that is painted bright red. The box should be located outside of the building and placed so that it cannot be handled by anyone other than the person called upon to open the valve in an emergency.
c.
In a glass fronted box that is painted yellow
d.
In a glass fronted box that is painted bright orange. The box should be located inside of the control room and placed so that it cannot be handled by anyone other than the person called upon to open the valve in an emergency.
e.
Outside of the engine room at a height of two metres
b.
In a glass fronted box that is painted bright red. The box should be located outside of the building and placed so that it cannot be handled by anyone other than the person called upon to open the valve in an emergency.
What controls the suction pressure in refrigeration systems?
Select one:
a.
Condenser cooling water
b.
Refrigeration flow
c.
Pressure relief valves
d.
Low-pressure control (LPC)
e.
Compressor inlet valve
d.
Low-pressure control (LPC)
Why are low-pressure cut-outs used on refrigeration systems?
Select one:
a.
To stop the compressor when the discharge pressure is too low
b.
To stop the compressor when the suction pressure drops too low
c.
To shut the system down due to non-condensable gases
d.
To stop the compressor when charging the system
e.
To stop the compressor on high pressure
b.
To stop the compressor when the suction pressure drops too low
