ammonia exam Flashcards
Calcium chloride brine solutions are suitable for food processing applications because it uses simple table salt in mixture (t or f)
f
when using an electric float for the control of ammonia systems a needle valve must always be used to control the amount of liquid refrigerant entering the chiller, this valve is normally located up stream of the liquid solonoid valve (t or f)
t
calcium chloride may be stored in the same location or equipment room as ammonia as long as there is no direct source of heat (t or f)
f
copper or brass may be used in ammonia systems as long as there is no moisture present in the equipment room (t or f)
f
the minimum test pressure for the lowside of an air cooled ammonia system is equal to or greater than the setting of the pressure relief device (t or f)
f
cascade is desirable if system temperatures of lower than -125 are required
t
the liquid recirculating pump as used with 2 stage liquid recirculation ammonia systems is located between
The low pressure receiver and the evaporator
the boiling point of r717 at atmospheric pressure is
-28f
when installing globe valves in any system for component isolation how should they be installed on horizontal line rows
the stem should be at right angles to a horizontal run of pipe and the high pressure side exerted on the bottom side of seat assembly
what component is not normally required in cascade systems
low stage condenser
which type of intercooler is not suitable for ammonia compression systems
dry type
multi stage or booster compression systems are normally required for low temp applications such as ammonia blast freezers. This type of compression system is normally good for applications above -90f and should be used if the reciprocating compression ratio of a single stage system exceeds
10;1
multi stage compression systems can be put in 2 groups
cascade or direct
ammonia receiver 3ft x 60’’ long what is the prv capacity
7.5 lbs per min
the corrosiveness of a brine or eutectic mixture should be maintained between _ and _ and can be determined by a ph tester
7-8.5
the normal temp drop through a lower temp chiller is normally
2f at a flow rate of 10 to 15 gallons per ton
normally ice temp is controlled by a brine thermostat if your sat suction temp is 8f what should your actual ice temp be
28f
centrifugal pumps are widely used in the industry what device can be found in the stuffing box of a centrifugal pump that has no moving parts
packing gland
1 closed circuit condenser water is not exposed to atmosphere
2 direct contact condenser water is not exposed to atmosphere
3 closed circuit condenser water is exposed to atmosphere
4 direct contact condenser water is exposed to atmosphere
1&4
what is the importance of the fill material as used in cooling tower design and construction
fill adds to the surface area of the cooling tower
2 types of fill material used
cedar strips and polyvinylchloride
term used for a mixture of salt and water to lower its freezing temp below 32f
eutectic mixture
under what condition should the operator or service tech wear a self contained breathing apparatus into an ammonia equipment room
300 ppm
most common sec refrigerant
water
what is particular code requirement with regards to the construction of a fire valve box for a class t machinery room
it has a glass front
term used to describe the constant dilution of cooling tower sump water
bleed water
a microprocessor controller analyzes the conductivity of the cooling tower sump water when the electrical conductivity is high what maintenance must be performed
indicates that the water is contaminated and must be drained and refilled
the liquid leaving the pipe on the discharge side of the system is the
point of free discharge
feet
head unit measurement
the head that appears only when the liquid is moving
friction head
the normal type of pump used in the industry
centrifugal pump
liquid entering the pump with the level below the center line of the pump
static suction lift
liquid entering the suction side of the pump
lift or head
the pressure that the pump must overcome on the discharge
total static head
pressure + velocity + friction heads
dynamic head
the head that is measured only when the pump is off
static head
dynamic + total static
total head
3 main groups of sec refrigerants
brines, glycol, alcohol
according to b52 indentify 6 design features that are required for an ammonia equipment room
b52 6.3
2 methods of demhumidification for curling or ice rinks
ventilation fans refrigerated dehumidifier
where should the fire valve be located on class t ammonia equipment room
7.5 feet off ground
under what condition should a operator wear an escape breathing respirator into an ammonia equipment room
incase of a sudden leak in the system
