Sealing tester, also known as sealing tester or sealing performance tester, generally refers to an instrument used for

 negative pressure principle testing and is an important tool for testing the sealing performance of packaging containers. 

Instruments are generally suitable for sealing tests of packaging bags, bottles, tubes, cans, boxes, etc. in industries such 

as food, pharmaceuticals, medical equipment, daily chemical products, automobiles, electronic components, stationery, 

etc. Sealing performance tests can also be conducted on specimens that have undergone drop and pressure tests.

Working principle of sealing tester

The working principle of the sealing tester is mainly based on the negative pressure testing principle, which is the

 detection method of the pressure difference inside and outside the packaging container. The specific process is as

 follows:

Differential pressure detection: Place the test sample in a sealed barrel and seal it properly. Then, use a vacuum pump

 to extract the air from the sealed barrel, creating a low-pressure and high-pressure zone on both the outside and inside 

of the test sample. The sealing tester will measure the pressure difference between these two areas and compare the 

results with the preset standard value.

Gas leakage detection: When the internal pressure of the container is lower than the external pressure, if there is a leak 

in the container, gas will flow from the inside to the outside, forming a gas leakage phenomenon. The sealing tester 

determines the sealing performance of the container by detecting this leakage phenomenon.

Bubble observation: In some cases, such as when using the water immersion method for testing, the sample is immersed 

in water and evacuated. If there is gas leakage inside the sample, the gas will escape from the sample and form bubbles. 

Therefore, the sealing performance of the sample can be judged by observing the appearance of bubbles.

How to use the sealing tester

The usage method of the sealing tester is relatively simple, and the following are the general operating steps:

Preparation: Connect the power supply and air source of the sealing tester (which can be directly connected to an air 

compressor or add a small inflation pump). Add an appropriate amount of testing water to the vacuum sealed tank, 

usually about three-quarters, to ensure that the distance between the product and the water surface is 25mm when 

the product is immersed in water or adjusted according to the instrument requirements.

Place the sample: Place the packaging container to be tested in the sealed can of the sealed tester, ensuring that the 

distance between the product and the water surface meets the requirements. Cover the top of the vacuum sealed 

canister to ensure a good seal.

Set parameters: Turn on the power switch of the sealing tester and set the vacuum value and testing time according

 to the standard testing parameters of the product.

Start testing: Open the test start button of the sealing tester, and the instrument will begin the vacuuming process. 

Observe the testing situation inside the vacuum sealed container within the set time, paying special attention to 

whether there are any bubbles escaping from the sample.

Result judgment: Determine the sealing performance of the product based on the observation results. If no bubbles 

escape and the sample can return to its original state after releasing the vacuum, it is considered that the product has

 good sealing performance.

End of test: After the test is completed, the sealing tester will automatically stop and give an alarm prompt. Automatically 

release pressure and replenish air. After the pressure value reaches zero, the vacuum sealed tank can be opened to remove 

the product.

In summary, the sealing tester determines the sealing performance of packaging containers by detecting the pressure 

difference inside and outside the container and observing gas leakage. Its usage is simple and clear, and it is an important 

tool for ensuring product quality and safety.