Instruction manual

VHS-4, VHS-6 and VHS-250 Diffusion Pumps
15
Explosive Conditions
Prohibited Action Explosion-Causing Condition
Do not run pump without cooling water. Overtemperature
Do not run pump with low level of pump fluid. Overtemperature
Do not run pump without proper backing or holding pump. Overpressure
Do not run pump when not evacuated below 0.5 Torr
(0.67 mbar).
Overpressure
Do not admit air to, or rough through, a pump with hot boiler. Overpressure plus strong oxidizer
Do not open drain or fill plug while pump is under vacuum,
especially when it is hot.
Overpressure plus strong oxidizer
Do not contaminate pump with explosive vapors. Lower explosive threshold
of gas mixtures
Do not remove, defeat, or override safety counter-measures such
as pressure and thermal switches and valve sequencer interlocks.
Overtemperature, overpressure,
more combustible mixtures
Do not machine or weld any part of the pump without removing
all oil or solvent residue in pump in large pumps.
Source of ignition
Do not use unsuitable pumping fluid, especially hydrocarbon oil. Lower explosive threshold
of gas mixture