Browse Prior Art Database

Vacuum Viscous Flow Trap

IP.com Disclosure Number: IPCOM000088854D
Original Publication Date: 1977-Aug-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Juras, AJ: AUTHOR

Abstract

Al(2)O(3) green sheet ceramic is thermally machined inside a vacuum chamber by a high-energy electron beam. The machining process produces a large amount of Al(2)O(3) particles. A vacuum is produced by removing gases from the chamber with a mechanical vacuum pump. Particles, which are transported down the chamber walls by viscous flow, get into the pump, causing contamination of the pump oil and pump wear. The viscous flow trap, illustrated in the figure, prevents foreign matter from the vacuum chamber from fouling the pump. An initial mechanical separation of air and particles is achieved by a deflector cap 10 directing the incoming flow down along the housing walls 12 into an oil bath 14 at the base, where any heat particles are deposited. D.C.

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Vacuum Viscous Flow Trap

Al(2)O(3) green sheet ceramic is thermally machined inside a vacuum chamber by a high-energy electron beam. The machining process produces a large amount of Al(2)O(3) particles. A vacuum is produced by removing gases from the chamber with a mechanical vacuum pump. Particles, which are transported down the chamber walls by viscous flow, get into the pump, causing contamination of the pump oil and pump wear. The viscous flow trap, illustrated in the figure, prevents foreign matter from the vacuum chamber from fouling the pump. An initial mechanical separation of air and particles is achieved by a deflector cap 10 directing the incoming flow down along the housing walls 12 into an oil bath 14 at the base, where any heat particles are deposited. D.C. 705 oil is used in the trap because of its vapor pressure and viscosity characteristics. An oil migration barrier 16 prevents this oil from entering the mechanical vacuum pump.

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