Vacuum Furnace Door Seal Grease
The role of lubricants in vacuum furnace seals.
Vacuum furnace door seal grease. The types of lubricants for vacuum service fall into three general categories. 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. As such it tends to be the cause of pump down issues about 80 of the time. A wet organic or silicone compound based oils and greases b dry lubricants including ptfe teflon and metal dichalcogenide compounds e g.
Click here to access the step by step instructions for the o ring or lip seal installation on a rotating vacuum furnace door. 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. If the pumping system is operating correctly then one of these failure modes is likely the cause. A damaged door seal vacuum furnace leaks and or hot zone contamination.
Lubricants for vacuum service are a diverse family of highly formulated products. Clean the chamber door or bottom head flange and lightly grease the o ring with a thin coating of high quality vacuum grease. Reapply a thin coating of vacuum grease as necessary. Graphite powder should be used on the lip seal.
Figure 11 16 debris ladden door seal. The first q a community for vacuum furnace end users and operators. 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. 1 if the door that houses the lip seal rotates the lip seal should be lubricated with dry graphite powder.
How to seal a leaking o ring with grease. 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. Molybdenum disulfide tungsten diselenide and c metal on metal combinations. Here the vapor pressure of the grease should be noted increases greatly with the temperature and should be well below the desired operating pressure.
Wipe the door o ring and flange with a clean lint free rag before closing the door. Do not grease the lip seal. Inspect and wipe clean this seal each time the door is opened after a furnace cycle.