Gross leak measurement in an incompressible test item in a film chamber

Patent metadata

Field	Value
Publication number	US-10900862-B2
Application number	US-201616063371-A
Country	US
Kind code	B2
Filing date	Dec 20, 2016
Priority date	Dec 21, 2015
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

The invention relates to a method for the gross leak measurement of an at least partially incompressible test object (18) in a film chamber (12) that comprises at least one flexible wall region and is connected, in a gas-conducting manner, to a pressure sensor (30), a vacuum pump (26) and, by way of a calibration valve (34), to a calibration chamber (36) enclosing a calibration volume (37), comprising the steps of evacuating the film chamber (12), measuring the pressure curve within the film chamber (12) after the evacuation is completed, connecting, in a gas-conducting manner, the calibration volume (37) to the inner volume of the film chamber (12) during the measurement of the pressure curve, the pressure being measured before the gas-conducting connection is established, and with the gas-conducting connection established, to the film chamber (12), and the pressure in the calibration chamber (36) prior to the connection to the film chamber (12) being higher or lower than the pressure in the film chamber (12), characterized in that the pressure difference Δpleer between the pressure before the gas-conducting connection is established and the pressure with a gas-conducting connection to the film chamber (12), in the case of an empty film chamber (12) comprising no test object (18), is compared to the corresponding pressure difference ΔpPrüfling when a test object (18) is present in the film chamber (12).

First claim

The invention claimed is:

1. A method for the gross leak measurement of an at least partially incompressible test object in a film chamber that comprises at least one flexible wall region and is connected, in a gas-conducting manner, to a pressure sensor, a vacuum pump and, by way of a calibration valve, to a calibration chamber enclosing a calibration volume, comprising the following steps:
evacuating the film chamber;
measuring a progression of a first pressure curve within the film chamber after the evacuation is completed;
connecting, in a gas-conducting manner, the calibration volume to the inner volume of the film chamber during the measurement of the progression first pressure curve, pressure being measured before the gas-conducting connection is established, and with the gas-conducting connection established, to the film chamber, and pressure in the calibration chamber prior to the connection to the film chamber being higher or lower than pressure in the film chamber,
wherein
the pressure difference Δp empty is the difference between pressure before the gas-conducting connection is established and pressure with a gas-conducting connection to the film chamber, in the case of an empty film chamber comprising no test object;
locating an object in the film chamber;
evacuating the film chamber;
measuring a progression of a second pressure curve within the film chamber when the test object is present after the evacuation is completed;
connecting, in a gas-conducting manner, the calibration volume to the inner volume of the film chamber during the measurement of the second pressure curve, pressure being measured before the gas-conducting connection is established, and with the gas-conducting connection established, to the film chamber, and pressure in the calibration chamber prior to the connection to the film chamber being higher or lower than pressure in the film chamber, wherein the pressure difference Δp testing is the difference between pressure before the gas-conducting connection is established and pressure with a gas-conducting connection to the film chamber when a test object is present in the film chamber; comparing Δp empty to Δp testing .

2. The method according to claim 1 , wherein the inner volume V inside of the film chamber, comprising the test object therein, is calculated as follows:

V
Inside

=

V
empty

⁡

(

Δ
⁢

⁢

p
empty

⁡

(

p
V

-

p

G
⁢

⁢
2

)

Δ
⁢

⁢

p
testing

⁡

(

p
V

-

p

G
⁢

⁢
1

)

-
1

)

or, when p G1 , p G2 <<p v

V
Inside

≈

V
empty

×

(

Δ
⁢

⁢

p
empty

Δ
⁢

⁢

p
testing

-
1

)

,

where
V inside : is the inner volume of the film chamber comprising the test object therein;
V empty : is the inner volume of the empty film chamber without the test object;
Δp empty : is the pressure difference between the pressure in the film chamber before connection to the calibration chamber and the pressure in the film chamber after connection to the calibration chamber, with an empty film chamber;
Δp testing : is the pressure difference between the pressure in the film chamber before connection to the calibration chamber and the pressure in the film chamber after connection to the calibration chamber, when a test object is present in the film chamber;
P G1 : is the final pressure that is present with an empty chamber after the calibration volume has been connected to the film chamber; and
P G2 : is the final pressure that is present with a chamber that contains a test object after the calibration volume has been connected to the film chamber.

3. The method according to claim 1 , wherein the inner volume of the empty chamber is determined by way of a comparative measurement of an empty chamber to a measurement having a know inner volume V Cal , using the following relatio

Assignees

• Inficon Gmbh

Inventors

• Decker Silvio
• Rolff Norbert

Classifications

• G01M3/36

  by detecting change in dimensions of the structure being tested · CPC title

• G01M3/3236

  by monitoring the interior space of the containers · CPC title

• G01M3/3218 Primary

  for flexible or elastic containers · CPC title

• G01M3/18

  for pipes, cables or tubes; for pipe joints or seals; for valves; {for welds; for containers, e.g. radiators} · CPC title

• G01M3/04

  by detecting the presence of fluid at the leakage point · CPC title