The Testing Principle and Technical Characteristics of the Packaging Airtightness Tester

Test Principle

Method One

This method is used for packages where the performance of the outer material under the action of water will not be significantly reduced during the test, such as packages with plastic film as the outer layer.
By evacuating the vacuum chamber, the sample immersed in water produces a pressure difference between the inside and outside, and observes the gas escape or water infiltration in the sample, so as to determine the sealing performance of the sample.

Method Two

This method is used for packages where the performance of the outer material will be significantly reduced during the test period under the action of water, such as a package with an outer layer of paper material.

Test device
The test apparatus shall be divided into the following parts.

Vacuum chamber: It consists of a vacuum container made of transparent material that can withstand a pressure of 100kPa and a sealed cover.

The vacuum container is used to hold the test liquid and the test sample; the sealing cover is used to seal the vacuum chamber. When vacuuming, the sealing cover should be able to ensure the airtightness of the vacuum chamber.

During the test, the maximum vacuum degree that can be achieved in the vacuum chamber should not be lower than 95 kPa, and the vacuum degree can be reached from normal atmospheric pressure within 30-60 s.

Sample fixture: used to fix the sample in the test liquid in the vacuum chamber, and its material and shape must not affect the performance of the sample and the test observation.

Pipeline: including the vacuum tube connected to the vacuum source and the exhaust tube connected to the atmosphere. Both shall be fitted with valves.

Vacuum gauge: It is used to measure the vacuum degree in the vacuum chamber, and its accuracy shall not be lower than 1.5 grade.

Control device: including vacuum switch, vacuum adjustment device, intake valve, etc.