Practice guide for selecting airtightness testing equipment

How to choose airtightness leak detection instruments

There are two main types of vacuum leak detection instruments:

1. Helium mass spectrometer leak detector

Principle: Inject helium gas into the tested product after being evacuated, and then use mass spectrometry analysis technology to detect the residual helium leakage rate in the product. Calculate the size of small cracks based on the law of helium escaping through collision.

Advantages: High detection sensitivity, capable of detecting up to 3 × 10 Å ¹³ Pa · m ³/ S-level micro leak detection rate, locate the leak location.

Disadvantages: Expensive equipment and high cost of helium gas.

Principle of helium mass spectrometry leak detection

2. Negative pressure airtightness tester

Principle: Use pressure/flow sensors to monitor the pressure and flow rate changes of the tested product in a negative pressure environment, and determine whether the gas is leaking.

Advantages: Simple operation, stable and reliable, and low cost.

Disadvantage: The detection sensitivity is slightly poor, and the minimum detectable accuracy resolution is 1Pa.

There are also two main types of positive pressure leak detection equipment:

1. Positive pressure airtightness tester

Principle: Inject high-pressure air into the tested product, detect the decay of internal pressure over time, and determine the airtightness.

Advantages: Easy to operate, fast detection, and good repeatability.

Disadvantage: Slightly low sensitivity to small leaks.

Principle of positive pressure airtight leak detection

2. Volume quantitative airtightness detector

Principle: Measure the volume of gas that seeps out of the tested component per unit time under a certain positive pressure.

Advantages: The system design is simple, cost-effective, and the results are accurate.

Disadvantage: It can only perform overall airtightness testing and cannot locate the leak location.