Instruction manual

1
High Throughput Diffusion Pumps
DRAFT 12/23/04
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 on page 2 for a list of prohibited actions
that can result in explosions, and Table 3 on page 3 for a list of pressurization hazards that can result in damage to
equipment.
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 General Hazards
Hazard Suggested Corrective Action
Loss of utility: water and/or electricity Provide sufficient backup water and power supply as
necessary to effect a safe shutdown under worst case
conditions
Overpressure in foreline 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)
Overtemperature Fit temperature sensors and pump fluid level sensors with
feedback to an interlock on the heater power supply
Insufficient water flow through the main cooling coils Use water flow sensor and feedback to interlock the heater
power supply
Water trapped between inlet and outlet of Quick Cool coil,
or liquid nitrogen trapped between inlet and outlet of liquid
nitrogen trap
Provide vent or pressure relief valves for both Quick Cool
coil and liquid nitrogen trap
Loss of electrical ground integrity Incorporate ground fault interrupt circuit into heater power
supply
Positive pressure in pumping system Integrate pressure relief valve in vacuum system to ensure
system pressure does not exceed 1 atmosphere
High voltage Prevent personnel contact with high voltages; design and
attach warnings
Toxicity and Corrosivity Vent toxic and/or corrosive gases to a safe location; ensure
adequate dilution or scrubbing to safe levels; take all action
required to meet air quality standards
Explosion Integrate pressure relief valves
Do not use hydrocarbon-based pumping fluids