System for analyzing permeation of a gas or vapor through a film or membrane

• US 4,656,865 A
• Filed: 09/09/1985
• Issued: 04/14/1987
• Est. Priority Date: 09/09/1985
• Status: Expired due to Fees

• Current Assignee: The Dow Chemical Company (Dow, Inc.)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Callan, Lawrence W.
• Primary Examiner(s): Levy, Stewart J.
• Assistant Examiner(s): Raevis, Robert R.
• Application Number:
  US06/774,107
• Time in Patent Office: 582 Days
• Field of Search: 73/1 G, 73/61.3, 73/64.2, 73/64.3, 73/19, 73/38
• US Class Current: 73/38
• CPC Class Codes: G01N 15/08 Investigating permeability, pore-volume, or surface area of porous materials
• CPC Class Codes: G01N 2015/086 of films, membranes or pellicules

Abstract

The invention is a system for measuring the permeation of a vapor or gas through a film or membrane. The device comprises a test cell which has two chambers which are separated by a membrane through which the permeation of a particular gas is measured. To one cell is fed a test gas or vapor either alone or in a mixture with a bulk gas. To the other side of the membrane is fed a bulk gas into which the permeating test gas or vapor permeates. Attached to the second chamber of the test cell is a means for analysis of the concentration of the test gas or vapor. This device further comprises a means for separately controlling the pressure in each chamber of the test cell. The device comprises a means for combining a portion of the bulk gas with the test gas or vapor in a manner such that the concentration of the test gas or vapor in the bulk gas can be carefully controlled. This means of combining the two gases is connected to the first chamber of the test cell. This system allows for the measurement of the permeation of a particular test gas or vapor through a particular membrane at widely varied temperature and pressure conditions.

Claims

1. A system for measuring the permeation of a vapor or gas through a film or membrane, the system comprising

(a) a means for introducing a test gas or vapor;

(b) a means for introducing a bulk gas;

(c) a restrictor adapted for regulating the flow of the test gas or vapor which is connected to the means for introducing the test gas or vapor;

(d) a second restrictor which is adapted for regulating the flow of the bulk gas which is connected to the means for introducing the bulk gas;

(e) a gas proportioner adapted for combining the test gas or vapor with a portion of the bulk gas and for regulating the flow and pressure of the combined test gas or vapor and a portion of the bulk gas connected to the first restrictor and the second restrictor;

(f) a rotometer adapted for controlling the flow and pressure of the bulk gas not combined with the test gas or vapor;

(g) a test cell comprising

(i) a first chamber inlet connected to the gas proportioner wherein the first chamber is adapted for passing combined test gas or vapor and bulk gas through the first chamber at a rate such that a portion of the test gas or vapor can permeate through a film or membrane;

(ii) a second chamber connected to the rotometer wherein the second chamber is adapted for flowing bulk gas through the second chamber and for receiving test gas or vapor which permeates through the membrane or film;

(iii) a means for securing the membrane or film between the first and second chambers such that any test gas or vapor which permeates through the membrane from the first chamber will pass into the second chamber;

(h) a means for introducing a calibration gas,

(i) a restrictor adapted for controlling the flow and pressure of the claibration gas;

(j) a second rotometer adapted for controlling the flow of the calibration gas;

(k) a gas chromatograph adapted for analyzing the concentration of test gas or vapor in a sample, which is connected to the second chamber of the test cell, the gas proportioner, or the second rotometer adapted for regulating the flow of the calibration gas;

(l) a means for regulating the flow of combined test gas or vapor and bulk gas between the first chamber of the test cell and the gas chromatograph, and the flow of bulk gas containing test gas or vapor which has permeated through the membrane or film to the second chamber, from the second chamber to the gas chromatograph;

(m) a first means for transferring heat which is in contact with the first chamber and is adapted for regulating the temperature of the first chamber; and

(n) a second means for transferring heat which is in contact with the second chamber and is adapted for regulating the temperature of the second chamber.

2. A system for measuring the permeation of a test gas or vapor through a film or membrane, the system comprising

(a) a means for introducing a test gas or vapor;

(b) a means for regulating the flow and pressure of the test gas or vapor connected to the means for introducing the test gas or vapor;

(c) a means for introducing a bulk gas;

(d) a means of regulating the flow and pressure of the bulk gas connected to the means for introducing the bulk gas;

(e) a means for combining the test gas or vapor and a portion of the bulk gas and adapted for controlling the pressure and flow of such, said means for combining the test gas or vapor and a portion of the bulk gas is connected to the means for regulating the flow and pressure of the test gas or vapor and further connected to the means for regulating the flow and pressure of the bulk gas;

(f) a test cell comprising

(i) a first chamber connected to the means for combining test gas or vapor and a portion of the bulk gas wherein the first chamber is adapted for passing combined test gas or vapor and a portion of the bulk gas through the first chamber at a rate such that a portion of the test gas or vapor can permeate through a film or membrane;

(ii) a second chamber connected to the means for regulating the flow and pressure of the bulk gas wherein the second chamber is adapted for flowing bulk gas through the chamber and for receiving test gas or vapor which permeates through the film or membrane;

(iii) a means for securing the film or membrane such that the film or membrane separates the first and second chamber;

wherein the pressure in the first chamber is regulated by the means for combining the test gas or vapor and a portion of the bulk gas; and

the pressure in the second chamber is regulated by the means for regulating the flow and pressure of the bulk gas;

(g) a means for analyzing the composition of a gas or vapor specially adapted for measuring the concentration of test gas or vapor, connected to the second chamber of the test cell or the means for combining the test gas or vapor and a portion of the bulk gas;

(h) a means for regulating flow of the combined test gas or vapor and a portion of the bulk gas, adapted for regulating the flow of combined test gas or vapor and a portion of the bulk gas from the means for combining the test gas or vapor and a portion of bulk gas between the first chamber of the test cell and the means for analyzing the composition of a gas or vapor.

(i) a first of transferring heat in contact with the first chamber adapted for regulating the temperature of the first chamber; and

(j) a second means of transferring heat in contact with the second chamber adapted for regulating the temperature in the second chamber.

3. The system of claim 2 which further comprises a means for introduction of a calibration gas or vapor;

and a means for regulating the flow and pressure of the calibration gas adapted for regulating the flow of calibration gas between the means for the introduction of the calibration gas and the means for analyzing the composition of a gas or vapor.

4. The system of claim 3 wherein the means for regulating the flow and pressure of the test gas or vapor comprises a restrictor.

5. The system of claim 4 wherein the means for regulating the flow and pressure of the test gas or vapor further comprises a regulator adapted for reducing the pressure of the test gas or vapor flowing from the source of the test gas or vapor.

6. The system of claim 4 wherein the means for regulating the flow and pressure of the bulk gas comprises a restrictor and a rotometer.

7. The system of claim 6 wherein the means for regulating the flow and pressure of the bulk gas further comprises a regulator adapted for reducing the pressure of the bulk gas from means for introducing a bulk gas.

8. The system of claim 7 wherein the means for combining the test gas or vapor and a portion of the bulk gas comprises a gas proportioner.

9. The system of claim 8 wherein the means for analyzing the composition of a gas or vapor comprises a gas chromatograph.

10. The system of claim 9 wherein the means for regulating the flow between the first chamber of the test cell, second chamber of the test cell, the means for analyzing the composition of a gas or vapor and the means for combining test gas or vapor and a portion of the bulk gas is a 4-way valve.

11. The system of claim 10 wherein the means for regulating the flow and pressure of the calibration gas comprises a restrictor and a rotometer.