Gas-selective permeable membrane and method of manufacturing thereof
AssigneeVarian, Inc.
InventorsRoberto Carboneri, Sandro Vittozzi
Life of this patent
Estimating the term…
Abstract
A gas-selective permeable membrane (1) utilisable in a leak detector for a gas, more particularly helium, comprising a sheet-like body (11) on which at least one reduced thickness area (15) is defined by removing a material from the sheet-like body. This at least one reduced thickness area (15) being permeable to at least one gas and formed so as that it is partly surrounded by a thicker and substantially gas-impermeable area (16) ensuring the structural strength of the membrane.
Claims19
A gas-selective permeable membrane comprising:
- a body (11) of a material permeable to at least one selected test gas and substantially impermeable to at least another gas, said body (11) comprises at least one reduced thickness area (15) highly permeable to said test gas, said reduced thickness area (15) being at least partly surrounded by a thicker area (16) ensuring the structural strength of the membrane;
- and
- heating means (17) comprising an electrical resistor partly covering and selectively heating said at least one reduced thickness area (15), wherein remaining areas of said body are at lower temperature.
An apparatus for gas leak detection, comprising:
- a vacuum-tight chamber;
- a vacuum pump connected to said chamber to bring the pressure in said chamber to a lower value than in an outside environment;
- a gas-selective permeable membrane separating at least a portion of said chamber from the outside environment, said membrane comprising:
- a body of a material permeable to at least one selected test gas and substantially impermeable to at least another gas, said body comprising at least one reduced thickness area highly permeable to said test gas, said reduced thickness area being at least partly surrounded by a thicker area;
- heating means for heating said at least one reduced thickness area with an electrical resistor partly covering, selectively heating said reduced thickness area, and providing temperature gradient between heated and unheated areas of said body;
- and
- means for detecting a presence of said at least one selected test gas in said chamber.
A method of manufacturing a gas-selective permeable membrane, comprising the steps of:
- providing a body (11) of a material permeable to at least one determined test gas and substantially impermeable to at least another gas;
- coating a face of said body (11) with a layer of amorphous silicon (53);
- coating said layer of amorphous silicon with a layer (55) of a photosensitive material;
- covering said photosensitive layer (55) with a lithographic mask (57) having a plurality of openings (59);
- submitting said face to ultra-violet ray irradiation;
- removing said lithographic mask (57) and submitting said face to a dry etching process by a plasma treatment;
- removing said layer (55) of photosensitive material and submitting said face to an ultrasonic drilling process;
- submitting said face to a wet etching process in a bath of an acid solution, and removing said amorphous silicon layer (53);
- forming at least one reduced thickness area (15) permeable to said at least one gas on said body (11), and
- applying a film of conductive material forming an electrical resistor (17) onto a planar sheet (51) of said body 11 by gluing or deposition.
Dependencies are inferred from the claim text.