Tpc 436 Piping Flashcards
(25 cards)
In a cooling system, one of the main lines in the piping system is the ____ line.
compressor
input
liquid
return
liquid
Steel pipe is typically joined by means of
brazing
flanges
flaring
soldering
flanges
Tubing is often preferred over piping in a cooling system, because it
• absorbs vibration better
• does not require deburring after cutting
• has greater wall thickness
• has a stronger seam
absorbs vibration better
Refigeration tubing is typically joined by
• flanges
• soldering
• threading
• welding
soldering
The function of the discharge line in a refrigeration system is to
• allow oil to flow back into the compressor
• allow refrigerant to drain
• convey the refrigerant to the condenser
•
reduce the refrigerant pressure
convey the refrigerant to the condenser
The “entrainment” of compressor oil is the _____ the moving refrigerant.
addition of oil to
drawing in and transporting of oil with recycling of oil in
removal of oil from
drawing in and transporting of oil with
In order to keep entrained oil droplets moving through the piping, the refrigerant must move at____ fom in horizontal piping and ____ fom in a vertical riser.
• 200 to 300; 200 to 300
• 500 to 700; 750 to 1,500
• 750 to 1,500; 500 to 700
• 750 to 1,500; 200 to 300
500 to 700; 750 to 1,500
Refrigerant can be prevented from collecting in the compressor during the off-cycle by installing
a(n)____in (on) the_____
check valve; discharge line
oil separator; discharge line
pressure relief valve; compressor recirculation line; compressor
check valve; discharge line
Accessories often added to a discharge line include a(n)
• discharge muffler
• heater
• oil injector
• single riser
discharge muffler
Subcooling is desirable in the liquid line, because it
• eliminates the need for a receiver
• lowers the pressure in the line
• maximizes condenser capacity
• reduces the volatility of the refrigerant
reduces the volatility of the refrigerant
If the pressure in the liquid line drops, flash gas can form , which can reduce the
oil circulation
power required to run the system
refrigerating effect
resistance to refrigerant How
refrigerating effect
With halocarbon refrigerants, the movement of oil is better in the liquid line than in the discharge line, because the
• droplets of oil join and form pools
• oil is miscible in most liquid refrigerants
• oil is removed before entering the liquid line
• refrigerant is cooler
oil is miscible in most liquid refrigerants
A liquid receiver is used to
allow the refrigerant to reach its saturation temperature
ensure subcooling of the refrigerant provide an even flow of refrigerant
store all the refrigerant during repairs
store all the refrigerant during repairs
The purpose of a solenoid valve in the liquid line is to stop the flow of refrigerant to the
• condenser
• evaporator
• receiver
• sight glass
evaporator
A double suction riser installed in a cooling system enables the system to operate at maximum load without creating excessive _____ in the suction line.
oil entrainment
pressure drop
refrigerant condensation
superheating
pressure drop
An accumulator in the suction line traps oil and liquid refrigerant to keep it from entering the _____ A heater in the accumulator evaporates the ____
• compressor; refrigerant
• condenser; oil
• evaporator; refrigerant
• receiver; oil
compressor; refrigerant
An evaporator-pressure regulator valve closes part way if the pressure at the evaporator outlet becomes too ____ A crankcase-pressure regulator valve closes part way if pressure at the
compressor inlet becomes too _____
high; high
high; low
low; high
low; low
low; high
The suction line is insulated in order to prevent or reduce ______ the line.
• air entry into
• condensation on the outside of
• cooling the refrigerant vapor inside
• noise from vibrations of
condensation on the outside of
The amount of oil that can build up in the suction line of an idle single-compressor system is much ____ than the amount that can build up in an idle compressor of a multiple-compressor system. To prevent damage from excessive oil buildup, the suction line should include a trap with the minimum rise of ____ in.
less; 6
less; 14
more; 6
more; 14
less; 14
Piping problems that result in operating problems are often caused by
air in the system
insufficient refrigerant charge
Liquid hammer
wax in the piping
Liquid hammer
Which of the following expansion joints can be used in a refrigerant line?
Ball
Bellows
Loop
Slip
Bellows
Which kind of support is appropriate for a horizontal piping run of 15 feet long?
Rod-type hanger
Roller-type hanger
Swivel-ring type hanger
Variable-spring base support
Rod-type hanger
The problems caused by vibration in the piping of a cooling system include
chemical breakdown of the refrigerant
damage to the valves and controls
ineffective lubrication of the compressor
reduced cooling capacity
damage to the valves and controls
Insulation is needed on the liquid line if the line is ____ than its surroundings. The purpose of insulation on the liquid line is to prevent the loss of any ____ of the refnigerant.
much colder; subcooling
slightly cooler, superheating
slightly warmer; subcooling
much hotter; superheating
much colder; subcooling
