The types of lubricants for vacuum service fall into three general categories.
Vacuum furnace door seal grease.
If the pumping system is operating correctly then one of these failure modes is likely the cause.
Do not grease the lip seal.
How to seal a leaking o ring with grease.
Click here to access the step by step instructions for the o ring or lip seal installation on a rotating vacuum furnace door.
As such it tends to be the cause of pump down issues about 80 of the time.
Lubricants for vacuum service are a diverse family of highly formulated products.
Here the vapor pressure of the grease should be noted increases greatly with the temperature and should be well below the desired operating pressure.
The vacuum grease smooth out small irregularities on the sealing surfaces and the surface of the o ring and thereby improves particularly at low degrees of deformation the sealing effect.
The door seal on a vacuum furnace sees some of the highest wear and tear through normal operation.
Graphite powder should be used on the lip seal.
2 if the door has a true autoclave design whereas the locking ring rotates around the stationary door then either vacuum grease and or graphite dust may be utilized.
Molybdenum disulfide tungsten diselenide and c metal on metal combinations.
The role of lubricants in vacuum furnace seals.
Inspect and wipe clean this seal each time the door is opened after a furnace cycle.
Despite what one may think excess vacuum grease does not aid in sealing and should be removed as it is a getter for shop debris which will interfere with the o ring s ability to seal.
A damaged door seal vacuum furnace leaks and or hot zone contamination.
A wet organic or silicone compound based oils and greases b dry lubricants including ptfe teflon and metal dichalcogenide compounds e g.
1 if the door that houses the lip seal rotates the lip seal should be lubricated with dry graphite powder.
Reapply a thin coating of vacuum grease as necessary.
Vacuum grease which you should use on the face of the seal and why methods for keeping the seal off the ground and clean during the installation process.
Clean the chamber door or bottom head flange and lightly grease the o ring with a thin coating of high quality vacuum grease.
On o ring seals look for cracks lack of elasticity flat spots dirt and metallic fines.
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