QR-25 Series
Quincy Compressor
52201-105, May 2003
6
3501 Wismann Lane, Quincy IL - 62305-3116
Control Components
Unloader Towers:
Provided as part of the basic compressor when control
version is specified.
Pilot Valve:
Used in conjunction with unloader towers when the compressor
is to run continuously and an operating pressure range is to be maintained.
Refer to your parts manual for correct pilot valve, ranges and settings.
Hydraulic Unloader:
Used on pressure lubricated compressors to protect the
compressor in the event of a potentially damaging oil pressure drop. Also
ensures that the compressor does not begin to produce compressed air until
there is sufficient oil pressure.
Pressure Switch:
Used for start/stop applications (usually accompanied by a
hydraulic unloader). The pressure switch detects the demand for compressed
air and allows the unit to start. When the demand is satisfied, the unit stops.
Control Versions
Various control versions are available for the model QR-25 series compres-
sors. The control version required is determined by how frequent there is
a demand for compressed air. The idea is to create compressed air on
demand, but to limit the number of times a motor must start the compressor
in a given time period. To prevent motor burnout, the motor should be
limited to no more than six (6) starts per hour.
Control Version P :
Describes a basic compressor with no added control
features.
Control Version L :
Consists of unloader tower(s)
*
located on the head of
the compressor, a hydraulic unloader mounted on the bearing carrier, and
a pressure switch. This version is recommended for those applications
where the compressor will not be required to start more than six (6) times
per hour. A compressor equipped with control Version L is sometimes referred
to as a “start/stop machine”
The pressure switch detects the demand for compressed air and allows
the unit to start. When the demand is satisfied, the unit stops.
The hydraulic unloader allows the compressor to start in an “unloaded”
state, that is, the compressor starts but does not begin to create compressed
air until oil pressure is established. The hydraulic unloader also guards
against excessive damage in the event of an oil pressure drop.
Control Version L Variations:
Variations of Control Version L are
illustrated in
Fig.s 2-3 & 2-4. Fig. 2-3
shows how a discharge line check
valve, pressure switch, & pressure relief valve are combined to provide
start/stop operation.
Fig. 2-4
is an example of how a Model 108 compressor
is equipped with a flyweight controlled three-way valve and head unloader
for start/stop operation.
FROM THE
AIR RECEIVER
HYDRAULIC
UNLOADER
P
UNLOADER TOWERS
Fig. 2-2 Control Version L
Pix 1069
AUTOMATIC
PRESSURE
SWITCH
CHECK
VALVE
TO
AIR
RECEIVER
PRESSURE
RELIEF
VALVE
Pix 1155
Fig. 2-3 Control Version L
Variation (Discharge Line
Check Valve & Pressure
Switch)
*1, 2, or 4 unloader towers are employed depending upon the model of compressor.
Содержание QR-25 Series
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