Operator Installation
& Instruction Manual
AUTO-PURGER
®
PLUS, APP
Non-condensible Gas (Air) &
Water Purger for Ammonia
Bulletin APP-001b
APR 2007
Operator Installation & Instruction
Manual for Models APP08, APP16,
APP24 and APPC
AUTO-PURGER
®
PLUS, APP
SECTION 1 INTRODUCTION
The internal surface area and flooded evaporator efficiency
gives the AUTO-PURGER Plus two to three times the foul
gas condensing capacity of an Armstrong Purger and 10
times the capacity of purgers with small electric hermetic
compressors. In a system with normal noncondensible
loads, all models will handle a 750 ton (2600 kW) ammonia
plant at suction pressures below atmospheric pressure or
a 1500 ton (5300 kW) ammonia plant at positive suction
pressures. The amount of noncondensibles in the system
is based on many factors including age, maintenance
practices, and operating temperature.
The number of purgers required for a system depends on
the number of installed purge points. Twenty-four purge
points is the maximum practical number per purger. For
example, a system with 24 points set to purge for 10
minutes per point requires a 240 minute (4 hour) cycle.
Each purge point can be purged 6 times a day. This may, or
may not, be adequate. Therefore, a second purger should
be used and the purge points divided equally between
the two purgers.
The AUTO-PURGER Plus can operate over a wide range of
condensing pressures. This is important for refrigeration
systems that operate at low condensing pressures during
cold ambient conditions.
The AUTO-PURGER Plus is a totally automatic, electronically-
controlled refrigerant noncondensible gas (air) and
water purger for reducing the energy costs of operating
an ammonia refrigeration system. All models are pre-
assembled, pre-wired, insulated, and include an automatic
water bubbler, a relief valve, and an isolation service valve
package. Installation requires piping the foul gas line, low-
pressure pumped-liquid line, low-pressure liquid return
line, suction line, water bubbler fill and drain lines, relief
valve vent line, water purge line to a customer supplied
container, and power connection, and wiring the remote
purge point solenoid valves. Purge point solenoid valves
must be purchased separately and must be a minimum
of ½” (13 mm) port size.
In addition, a computerized model—APPC—is available
where a separate plant computer or programmable logic
controller (PLC) is used to independently operate the
various remote purge point solenoid valves.
Water contamination in an industrial ammonia refrigeration
system can lower system efficiency, and increase the
electrical costs required to run the system’s refrigeration
compressors. Ammonia refrigerant that is contaminated
with water requires a lower suction pressure to maintain
the same evaporator temperature than would pure
ammonia refrigerant. The requirement to maintain a
lower suction pressure than would be necessary if the
water contamination were removed is a waste of electrical
energy. For water removal, the AUTO-PURGER Plus has
the following capacities:
5% system water concentration – 3 gallons of water
removed per day
10% system water concentration – 5 gallons of water
removed per day
20% or more system water concentration – 7 gallons of
water removed per day.
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