Browse Prior Art Database

Diffusion Pump

IP.com Disclosure Number: IPCOM000079253D
Original Publication Date: 1973-Jun-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Nuccio, C: AUTHOR [+3]

Abstract

Shown is an improvement, in a diffusion pump, obtained by configuring the top hat in the form of a conical surface with its apex pointing towards the boiler. This geometry is conducive to exiting a larger portion of the rising vapor and imparts a velocity component of the vapor stream towards the nozzle opening, thus increasing the exit velocity with a resulting improved pumping efficiency. Further, the increased vapor density at the nozzle exit aperture permits a pump of larger diameter to have the same efficiency, without the disadvantage of increased back streaming. In addition, the implementation of a larger pump can now be made by changing only the outer cylinder diameter, while maintaining the smaller jet assembly.

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Diffusion Pump

Shown is an improvement, in a diffusion pump, obtained by configuring the top hat in the form of a conical surface with its apex pointing towards the boiler. This geometry is conducive to exiting a larger portion of the rising vapor and imparts a velocity component of the vapor stream towards the nozzle opening, thus increasing the exit velocity with a resulting improved pumping efficiency. Further, the increased vapor density at the nozzle exit aperture permits a pump of larger diameter to have the same efficiency, without the disadvantage of increased back streaming. In addition, the implementation of a larger pump can now be made by changing only the outer cylinder diameter, while maintaining the smaller jet assembly.

Also, increased surface area of the top hat provides for a lower top-hat temperature and, when used with a cold cap, improved cooling rate of the top hat. An additional advantage allows oil (heavier fractions) that may collect on the lower surface of the top hat to return directly to the boiler, which also reduces the effect of oil-back streaming resulting in a cleaner pump.

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