Steel drum æ°¦ mass spectrometer leak detection

Steel drum æ°¦ mass spectrometer leak detection

The good or bad airtightness of the steel drum directly affects its performance and safety, especially for steel drums containing special substances (such as polluting substances or toxic substances).

The blister leak detection method is an old and simple method for leak detection, but the tested parts must be launched, which brings trouble to the drying of the product, and the volume of the steel drum is generally large, which is inconvenient to launch; in addition, the blister method Leak detection can only be done by visual observation. The sensitivity of leak detection is generally up to 10-5Pa.m3/S, but the difference is very large, which does not meet the precise requirements of the actual production occasion.
At present, many manufacturers have begun to adopt the helium leak detection method. The helium mass spectrometer leak detection method is a leak detection method in which helium is used as a search gas for leak holes and a mass spectrometer is used to detect leaks of leaks. The utility model has the advantages of high reaction speed, high detection precision, large detectable range, non-toxicity, no pollution, high efficiency and no radioactivity.

The helium leak detection method is generally divided into the evacuation method and the filling method. According to the working condition of the steel drum, the positive pressure is generally used. Therefore, the filling method is used to detect the leak. The filling method mainly includes a sniffer method and a vacuum box method, that is, after filling a workpiece with a predetermined pressure of helium, the sniffer of the leak detector is brought close to the suspected leak point of the workpiece, and the inhalation method is used for leak detection, or the filling method is performed. The gas workpiece is placed in a vacuum box slightly larger than the workpiece. After vacuuming the vacuum box through the pump set, it is connected to the leak detector to measure the overall leak rate of the workpiece. The sniffer method is relatively simple, but the workpiece is large and easy to miss, and the leak detection accuracy, speed and automation are not as good as the vacuum box method.

The vacuum tank method is used to detect leaks in steel drums. The main processes are as follows:

1. Filling: Fill the steel drum with helium gas of the specified pressure. Since the steel drum can not withstand higher vacuum and higher pressure, the method of directly charging a certain amount of helium into the barrel is adopted, and the radon concentration is about the volume of the helium gas/the inner volume of the steel drum (before filling) A certain amount of clean air can be introduced into the steel drum to remove the dirty air in the steel drum. Immediately after the helium gas is filled, the steel drum is sealed.

2. Place the steel drum filled with helium into the vacuum box. After the vacuum pump vacuums the vacuum box to the specified vacuum degree, the leak detector communicates with the vacuum box. If the steel drum leaks, the helium gas enters the vacuum box through the leak hole. The leak detector measures the helium signal in the vacuum box and the leak rate value. If the set value is exceeded, it will be unqualified.

When using the vacuum box method to detect leaks, the steel drum can automatically enter the vacuum box through the workpiece conveying device, and then manually press the start button, the vacuum box door can automatically close the door, vacuuming, leak detection, etc., and the system will prompt, no Qualified automatic alarm, the degree of automation is extremely high, and the beat is also fast, up to 2~3 workpieces/min.