In industries such as food, pharmaceuticals, medical devices, and daily chemical products that require packaging integrity, the sealing performance of packaging directly affects the shelf life, safety, and consumer experience of the product. Once there is a minor leakage in the packaging, it may lead to contamination of the contents, oxidation and deterioration, microbial invasion, and even medical accidents. To ensure that every package of products has reliable sealing, the packaging sealing detector, as a key equipment for quality control, is widely used in production line sampling, research and development verification, and factory inspection, becoming the "guardian" of modern packaging quality management system.

1、 The basic significance of packaging sealing testing

Packaging sealing refers to the ability of a packaging system to prevent the entry of gases, liquids, or microorganisms under specified conditions. Minor leaks (such as pinholes, false seals, indentation cracks) are difficult to detect with the naked eye, but can cause serious consequences during transportation, storage, or use. For example, leakage of drug packaging may cause damage to the sterile environment; Vacuum food packaging leakage can accelerate spoilage; Damaged packaging of sterile medical devices poses a risk of infection.

Therefore, evaluating packaging sealing performance through scientific and reproducible testing methods is not only an inherent requirement for enterprise quality control, but also a mandatory requirement to meet international regulations such as GMP (Good Manufacturing Practice), FDA 21 CFR Part 11, ISO 11607, etc.

2、 The working principle and main technical types of packaging sealing detector

The packaging sealing detector simulates or applies specific physical conditions to detect changes inside or outside the packaging, in order to determine whether there is a leak. According to different detection principles, it can be mainly divided into the following categories:

1. Vacuum Decay Method

Place the test package into a sealed testing chamber, evacuate to a certain degree of vacuum, then turn off the gas source and monitor the pressure inside the chamber over time. If there is a leakage in the packaging, external air will gradually seep in, causing a decrease in vacuum degree (i.e. "decay"). By measuring the attenuation rate with high-precision pressure sensors, the size of the leak can be quantitatively determined. This method has high sensitivity (can detect leaks of 5-10 μ m) and is suitable for various rigid and semi-rigid packaging, such as blister packaging, vacuum bags, infusion bags, etc.

2. Pressure Decay Test

Fill the interior of the packaging with a certain pressure of gas (such as compressed air), then turn off the gas source and monitor the pressure drop. Suitable for hard containers that can withstand internal pressure, such as plastic bottles, metal cans, etc. Simple operation and low cost, but not suitable for flexible packaging.

3. Dye Penetration Test

Immerse the packaging in a colored liquid (such as methylene blue solution), apply vacuum or pressure, and observe if any dye solution seeps into the interior of the packaging. This method is intuitive, low-cost, and commonly used for laboratory validation, but it belongs to destructive testing and is not suitable for online full testing.

4. Bubble Test

Place the packaging in water and apply internal pressure to observe if any bubbles escape from the leak point. Suitable for detecting large-sized containers or welds, with simple operation but low sensitivity.

5. Ultrasonic testing and laser gas analysis

Emerging technologies, such as using laser tunable absorption spectroscopy (TDLAS) to detect changes in the concentration of specific gases (such as O ₂, CO ₂) inside packaging, indirectly determining sealing performance; Or use ultrasonic waves to detect structural defects in the sealing area. These methods are non-contact and high-precision, and are gradually being applied in the fields of pharmaceuticals and medical devices.

3、 Equipment composition and core functions:

Test chamber: accommodates the packaging to be tested, made of stainless steel with good sealing performance;

High precision pressure sensor: with a resolution of up to 0.1Pa, ensuring that small leaks can be captured;

Vacuum pump and solenoid valve group: achieve rapid vacuum pumping and pressure maintenance;

Control system: Built in microprocessor, can set test parameters (vacuum degree, holding time, qualified threshold);

Human Machine Interface (HMI): Touch screen operation, display test curves, result judgment (pass/fail);

Data management: Supports USB export, printer output, or connection to LIMS system to meet audit tracking requirements.

Although the packaging sealing detector does not directly participate in production, it is the last line of defense for product quality. It uses technological means to 'listen' to the breathing of each package of products, ensuring their sealing is intact, safe, and reliable. In today's increasingly high demand for quality among consumers, investing in advanced sealing and testing technology is not only a compliance requirement, but also the cornerstone for enterprises to win market trust.