Leakage detection method

Bonfiglioli leak test equipment

Leakage detection and measurement methods have recently received increasing attention from the legislature (such as environmental protection, health care, etc.). This makes all relevant standards and norms more rigorous and clear.

Therefore, in order to control and ensure the quality of the production and packaging process, the quality inspection department must clearly understand the different test methods.

Containers and accessories used to hold various fluids (liquids or gases), such as cans, bottles, food bags, containers for cosmetics and medicines, must ensure that their contents do not leak and must prevent foreign fluids from entering the container. Inside. In technical terms: The container must not leak, and the container must maintain its original pressure. Such concepts have precise definitions in national and international standards.

The three main reasons for leak testing can be stated as follows:

â—† Prevent leakage of material in the container, so as not to affect the effectiveness of its products.
â—† Prevent contamination (dangerous or harmful substances) from leaking.
â—† Prevent unreliable ingredients (components that do not meet the standard requirements) reach the end consumer.

Leakage tests have historically included some form of blistering test, usually performed by skilled operators in dusty, high humidity, and temperature changing environments. The goal of this test is relatively simple. It is to see if a container placed in the water emits a string of bubbles to determine if the container is leaking. Although this test can detect very small leaks and pinpoint their exact location, this method does not measure the exact leak rate. After testing, this container must be dried, which greatly affects the speed of operation.

Selecting an appropriate dry air leak sensor, coupled with a computing device and microprocessor-controlled test system, results in a faster test cycle that is necessary for the test, so that more stringent anti-leakage specifications can be applied.

Since 1974, Bonfiglioli Engineering has specialized in the design and manufacture of leak test equipment, providing leak testing methods for various industries. Located in Ferrara, Italy, Bonfiglioli's business clients include: Manufacturers of blow molding machines, can/aerosol production companies, and packaging companies involved in various fields such as food, beverages and pharmaceuticals. Through a strong agency network, Bonfiglioli sells various leak testers to customers worldwide, and has earned a high reputation for its excellent after-sales service.

Constant research and development has made Bonfiglioli Engineering a world leader in the field of leak testers. Taking full account of customer needs, the company designs and manufactures each device that meets CE standards and can meet any container leak detection.

In practical applications, various test methods can be used. The method commonly used to test empty containers is pressure decay, whereas the containers that are tested and sealed are vacuum-attenuated. The following is a brief description of these methods.

Pressure decay method

Test Products: Aerosol Can / Food Can / Plastic Container / Aluminum Tube / PET Bottle Instrument Type: Stern/HSL/ RLD/VLD

In this test set, air was continuously blown into the container until its internal pressure reached a predetermined value, or a predetermined time passed. During the test cycle, the pressure in the container is monitored. Based on the pressure change and the pressure value compared with the predetermined critical value, the container will be determined as pass or fail.

Vacuum decay method

Test products: filled and sealed cosmetics, food and packaging containers.
Instrument Type: RLD 400

The container being tested is sealed and usually filled with liquid, leaving only a small air gap at the top of the container (for example, a milk bottle sealed with aluminum foil). This test is used to test the airtightness of this part of the container (ie the neck of the container).

Insert the top of the container into the test head with the gas seal ring. When pressurized (or blown), the gas sealing ring clings to the wall of the container to create a strong seal. In the sealed test cell, vacuum is generated due to the air being sucked. During the entire test cycle, the special sensor controls the degree of vacuum in the test cell from beginning to end.

Load cell method

It is also possible to test the tightness of plastic or metal bags by using load cells. The bag under test was placed on the lower conveyor. The upper conveyor was above the bag and its height was adjustable. The upper conveyor forces the tested area of ​​the bag placed on the lower conveyor. The movement of these two transmitters is synchronized. On the lower conveyor, there is a gravity balance at the entrance and exit of the test cycle.

The gravity balance at the beginning of the test cycle is read first. The size and elasticity of the bag determine the pressure that the upper conveyor creates on the bag.

At the end of the test cycle, the gravity balance reads the second data. If the data measured by the two balances is equal to or less than the predetermined upper limit, the bag can be considered qualified. Otherwise, if the difference between the two readings is greater than the predetermined upper limit, the bag is an unqualified product.