Browse Prior Art Database

Reproducible Variable Permeation Tube

IP.com Disclosure Number: IPCOM000074251D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Frankel, H: AUTHOR [+2]

Abstract

This is a reusable, reproducible variable permeation tube for varying the concentrations of addition gasses in a carrier gas without changing the flow rate or the temperature of the carrier gas.

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Reproducible Variable Permeation Tube

This is a reusable, reproducible variable permeation tube for varying the concentrations of addition gasses in a carrier gas without changing the flow rate or the temperature of the carrier gas.

The permeation tube, illustrated in the figure, comprises a length of polymer tubing 10 closed at one end with a cap 12 and containing a liquified addition gas. The tubing 10 can be constructed of any material, including inert polytetrafluorethylene, which is permeable to the addition gas contained therein. The amount of addition gas diffusing through the walls of the tubing 10 depends upon the temperature of the addition gas and the surface area of the walls of the tube 10 exposed to the carrier gas. The other end of the tube 10 is sealed by an appropriate valve assembly 14 held to the tube by a compression fitting 15. Fitted on the tube 10 is an adaptor 16 for mating the tube with an inlet port 17 in the chamber 18 containing a flowing carrier gas. Secured to the adaptor 16 is an O-ring coupler 19 containing two O-rings 20 and 21 which provide a compression fit to the tube.

The valve assembly 14 permits reproducible filling of the tube 10 with a liquified addition gas and since the tube dimensions are fixed it need be calibrated only once. The O-ring coupler 19 permits the amount of addition gasses in the carrier gas to be changed by the simple expedient of pushing the tube further into the chamber 18 or by withdrawing it so that th...