Varian VHS-250, Инструкция по эксплуатации

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VHS-4, VHS-6 and VHS-250 Diffusion Pumps
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Pressurization Hazards
Large vacuum pumps and their components are designed for vacuum service. They are not
designed to be pressurized, which can cause them to burst and possibly expel shrapnel at
lethal velocities. Serious accidents have been caused by intentional pressurization of
vacuum systems and their components.
❑
Never pressurize any part of a vacuum system for test or any other purpose.
❑
Always provide pressure relief when designing diffusion pumps into systems and
ensure that pressure relief motion is limited to safe envelopes.
❑
Never permit any of the hazards in the table below to develop.
Pressure Relief Devices
Systems larger than 10”, such as this pump, must be designed with pressure relief devices to
provide safe pressure relief from internal explosions. Always recognize that safety devices
can fail or malfunction; provide redundant protection by installing devices having different
failure modes, failure mechanisms, and failure causes. Be certain that exhaust duct
materials are capable of withstanding the corrosivity, temperature, and pressure of
exhausted products.
Pressurization Hazards
Prohibited Action Result
Do not block inlet or vent of liquid nitrogen trap and lines. LN
2
trap and/or lines burst
Do not close isolation valves at inlet and discharge of main
water cooling coils when pump is reheated. Water turns to steam and bursts coils
Do not pressurize the pump body. Body of pump bursts
Do not make a hole through the vacuum wall. Loss of structural integrity of wall