Instrutech VGC-301 User Manual page 25

Instruction Manual
In some processes, solid particles are created during the process, throughout the chamber, including inside
the gauge. Particles tend to form on cooler surfaces, such as in a gauge at room temperature. You may
slow down the build-up of particles in the gauge, by keeping the gauge warm (within specified limits) during
the process cycle.
More commonly, particles in the process chamber are swept into the gauge during the vent cycle.
InstruTech gauges have a screen built into the gauge port, to help keep the largest particles out of the
gauge. In very dirty applications, or where particles are small enough to get through the screen, an
additional filter installed on the inlet may help prolong gauge life further.
C) Cleaning Procedures
Caution: Cleaning chemicals and their handling pose a variety of health, safety, and environmental
issues. Protect yourself, your co-workers, and your surroundings, by using protective clothing
(gloves, eyewear, etc), performing the cleaning in a well-ventilated area, and disposing of waste
materials in a responsible manner.
Cleaning solvents:
To be effective, the cleaning agent should be one that is likely to remove the suspected contaminant. It
must also be compatible with the gauge materials of construction. Alcohol and water are recommended
cleaning solvents, as they are compatible with most vacuum systems and components, and will remove
many contaminants commonly found in vacuum processes, such as pump oil. However, depending on
your particular contamination, you may need to use a more aggressive solvent.
Cleaning procedure:
1. With the gauge port up, pour your cleaning solution into the gauge port until it is full. Note: The fine
mesh of the port screen may not allow the solution into the gauge tube because of surface tension effects.
You may need to insert a small tool into the gauge vacuum port to push the port screen slightly away from
the tube wall to allow solvent into the gauge. ("Slightly away" means less than about a millimeter.) Make
sure the tool is not plated with high vapor pressure material such as zinc plating.
2. Let the solution sit for a while, 10-20 minutes should be sufficient. Gentle agitation will help disperse the
solution throughout the gauge, but do not shake the gauge vigorously. (While the InstruTech gauge is
constructed to be rugged, it was not designed to withstand forces exerted by liquids in motion.)
3. With the gauge port down, pour the solution out of the gauge and leave it to drain and dry for several
hours or overnight. Warming the gauge, and/or pumping on it, will speed up the drying time.
4. When you are sure the gauge is completely dry, install it on a vacuum system, apply power, and run
through the calibration setup. Pump the gauge below 10
set. If zero is ok, raise pressure and set the atmosphere adjustment.
5a. If both zero and atm can be set properly, you have successfully cleaned your gauge.
5b. If zero or atm cannot be set, the gauge has been contaminated beyond recovery and must be
replaced. (You can try cleaning it again, but if the first pass doesn't recover the gauge, additional cleanings
are not likely to succeed.)
InstruTech, Inc
InstruTech VGC-301 Convection Vacuum Gauge Controller
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Torr and confirm that the zero/vacuum can be
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