Leak test method and leak test apparatus

Patent metadata

Field	Value
Publication number	US-9404828-B2
Application number	US-201214353406-A
Country	US
Kind code	B2
Filing date	Oct 22, 2012
Priority date	Oct 26, 2011
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

A leak test method includes: reducing first pressure in an inspection space in a work and second pressure in a space in a master chamber; humidifying the inspection space in the work; and detecting a change in differential pressure between the inspection space in the work and the space in the master chamber, while the inspection space in the work is in a water-vapor saturated state. Also, in this leak test method, a leak in the inspection space in the work is detected from the change in the differential pressure.

First claim

The invention claimed is:

1. A leak test method comprising:
reducing first pressure in an inspection space in a work and second pressure in a space in a master chamber;
humidifying the inspection space in the work; and
detecting a change in differential pressure between the inspection space in the work and the space in the master chamber, while the inspection space in the work is in a water-vapor saturated state,
wherein a leak in the inspection space in the work is detected from the change in the differential pressure.

2. The leak test method according to claim 1 , wherein in humidifying the inspection space in the work, the first pressure is reduced while water-retentive material is arranged in the inspection space in the work.

3. The leak test method according to claim 1 , wherein:
in humidifying the inspection space in the work, the inspection space in the work is humidified from outside by introducing fluid into the inspection space in the work by a humidifying device that is connected to the work; and
the fluid includes water vapor.

4. The leak test method according to claim 3 , wherein the first pressure and the second pressure are reduced simultaneously with humidification of the inspection space in the work by reducing the first pressure, while a flowrate of the fluid introduced into the inspection space in the work is regulated by a throttle valve.

5. A leak test apparatus comprising:
a master chamber;
a pressure-reducing device that is configured to reduce first pressure in an inspection space in a work and a second pressure in a space in the master chamber;
a humidifying device that is configured to humidify the inspection space in the work; and
a detecting device that is configured to detect a change in differential pressure between the inspection space in the work and the space in the master chamber, while the inspection space in the work is in a water-vapor saturated state,
wherein a leak in the inspection space in the work is detected from the change in the differential pressure.

6. The leak test apparatus according to claim 5 , wherein:
the humidifying device includes water-retentive material arranged in the inspection space in the work; and
moisture in the water-retentive material is vaporized by reducing the first pressure.

7. The leak test apparatus according to claim 5 , wherein:
the humidifying device is connected to the work, and humidifies the inspection space in the work from outside by introducing fluid into the inspection space in the work; and
the fluid includes water vapor.

8. The leak test apparatus according to claim 7 , further comprising a throttle valve that is configured to regulate a flowrate of the fluid introduced into the inspection space in the work,
wherein the first pressure and the second pressure are reduced simultaneously with humidification of the inspection space in the work by reducing the first pressure, while the flowrate of the fluid introduced into the inspection space in the work is regulated by the throttle valve.

Assignees

• Yamaguchi Tetsuya
• Toyota Motor Co Ltd

Inventors

• Yamaguchi Tetsuya

Classifications

• G01M3/3263

  using a differential pressure detector (G01M3/3245, G01M3/3272 take precedence) · CPC title

• G01L19/0092

  Pressure sensor associated with other sensors, e.g. for measuring acceleration or temperature (G01L9/025, G01L9/045, G01L9/065, G01L9/085, G01L9/105, G01L9/125, G01L19/02, G01L19/04 take precedence; measuring two or more variable G01D21/02; temperature sensors with pressure compensation G01K1/26) · CPC title

• G01M3/34

  by testing the possibility of maintaining the vacuum in containers, e.g. in can-testing machines · CPC title

• G01M3/025 Primary

  Details with respect to the testing of engines or engine parts · CPC title

• G01M3/02 Primary

  by using fluid or vacuum · CPC title