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Technical Information
Diffusion Pump Hazards
Designers of systems utilizing diffusion pumps must design out hazards wherever
possible. For hazards that cannot be designed out, warnings, procedures, and
instructions on proper use and servicing are provided. Please use guards, safety
features, and interlocks as recommended.
Refer to Table 1 for a list of general hazards and recommended actions, Table 2 for a
list of prohibited actions that can result in explosions, and Table 3 for a list of
pressurization hazards that can result in damage to equipment.
The end user must ensure the pump is properly protectively bonded to the end
product's protective earthing system as determined in the end product standard for the
End Product Design. End Product Design provides a compliant fire enclosure as defined
in the End Product's standard.
THE INSTALLATION, OPERATION, AND SERVICING OF DIFFUSION PUMPS INVOLVES
ONE OR MORE OF THE FOLLOWING HAZARDS, ANY ONE OF WHICH IN THE
ABSENCE OF SAFE OPERATING PRACTICES AND PRECAUTIONS, COULD
POTENTIALLY RESULT IN DEATH OR SERIOUS HARM TO PERSONNEL.
Table 1
Hazard
Loss of utility: water and/or electricity
Overpressure in foreline
Overtemperature
Insufficient water flow through the main cooling
coils
Water trapped between inlet and outlet of Quick
Cool coil, or liquid nitrogen trapped between inlet
and outlet of liquid nitrogen trap
Loss of electrical ground integrity
Positive pressure in pumping system
High voltage
Toxicity and Corrosivity
Explosion
High Throughput Diffusion Pumps User Manual
General Hazards
Suggested Corrective Action
Provide sufficient backup water and power supply as
necessary to effect a safe shutdown under worst
case conditions
Provide an interlock to ensure that the power supply
to the pump heater cannot be activated if the foreline
pump is not running and/or the pressure in foreline is
above 0.5 Torr (0.67 mbar)
Fit temperature sensors and pump fluid level sensors
with a feedback to an interlock on the heater power
supply
Use water flow sensor and feedback to interlock the
heater power supply
Provide vent or pressure relief valves for both Quick
Cool coil and liquid nitrogen trap
Incorporate ground fault interrupt circuit into heater
power supply
Integrate pressure relief valve in vacuum system
Prevent personnel contact with high voltages; design
and attach warnings
Vent toxic and/or corrosive gases to a safe location;
ensure adequate dilution or scrubbing to safe levels;
take all actions required to meet air quality standards
Integrate pressure relief valves
Do not use hydrocarbon-based pumping fluids
17
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