Quincy Compressor 50093-103 - Manual (Page 46)

40
Section 4 - Procedures
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Prior to Starting
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Starting the Vacuum Pump
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Stopping the Vacuum Pump – Normal Operation
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Stopping the Vacuum Pump – Emergency Operation
Prior to Starting
Before starting the unit, review Sections II and III of this
manual and be certain that all installation requirements
have been met and that the purpose and use of each of the
controls, warnings and gauges are thoroughly
understood. The following checklist shall be adhered to
before placing the vacuum pump into operation:
! WARNING !
Be sure the vacuum pump is grounded.
•
Remove all loose items and tools from around the
vacuum pump installation.
•
Check fluid level in the air/fluid reservoir.
•
Check the fan and fan mounting for tightness.
•
Manually rotate the vacuum pump through enough
revolutions to be certain there are no mechanical
interferences.
•
Check all connections for tightness.
•
Check to make sure all relief valves are in place.
•
Check to make sure all panels and guards are in place
and securely mounted.
•
Check fuses, circuit breakers and thermal overloads for
proper size.
•
Open all manual shut-off valves (block valves) beyond
the air/fluid reservoir.
•
Check the inlet filter element to see that it is securely
mounted.
After all the above conditions have been satisfied, close
the main power disconnect switch, jog the starter switch
button to check the rotational direction of the vacuum
pump. The vacuum pump and fan must rotate clockwise
when facing the vacuum pump from the shaft end on the
QSVI 25, 50, 75, 100 and 200. On QSVI 40, the rotation is
counter-clockwise.
Starting the Vacuum Pump
Be sure that the exhaust line is open on the dry side of
air/fluid reservoir to ensure that no back pressure is added
to the pumping system.
Start the vacuum pump and watch for excessive vibration
or strange noises. If either is observed, stop the pump
immediately and correct. See stopping instructions.
Control System - The control system vacuum settings
are factory set, however, they should be checked at
the startup as noted previously. Following is a
discussion of checking and adjusting the vacuum
control system.
In order to make the discussion clear, certain terms need to
be understood. Range is that region of vacuum levels
desired in the system. The range has a maximum value
above which the system vacuum level should not rise, and
a minimum level below which the system vacuum level
should not fall. A typical range would be from 23" HgV
vacuum to 20" HgV vacuum. The differential for this range
is 3" HgV which is the difference between the maximum
and minimum settings of the range. Range and differential
are interchangeable. Upper set point and upper trip point
both refer to the maximum value of the range (23" HgV).
Lower set point and lower trip point both refer to the
minimum value of the range (20' HgV). The vacuum
regulator is usually set to operate at the lower set point,
and that is where it will be set if this adjustment is
followed.
The three items to be checked and adjusted, if necessary,
are:
1.) The vacuum switch differential 2.)
The vacuum switch range
3.) The vacuum regulator set point
In order to make these adjustments an easy means of
varying air flow into the vacuum pump is required, so that
even when the vacuum pump is running at fall capacity
the system vacuum level can be lowered below the lower
set point. If this is not possible, the plant vacuum system
must be disconnected from the vacuum pump inlet and a
hand valve screwed into the 3" pipe tap in the vacuum
pump inlet.