Leak detection system for canned goods
Application
Canned infant food and milk powders
The question
Canned infant food and milk powders are tested randomly for leaks by the producer after filling and sealing. This is done with a so-called leak test manipulator. This manipulator consists of a vacuum dome which completely encloses the can and a helium leak tester. The cans to be tested have already been aerated in the filling machine with a higher percentage of helium and then moved into the manipulator. The dome is evacuated until it is within the range of the helium leak tester. If there are any leaks, helium will escape from the can to the helium leak tester. The helium leak tester has a mass spectrometer that is tuned to helium. The mass of gas to be measured is converted with the measured pressure to a leak value in mbarl/sec. This is the value for approval or rejection of the can.
Up until now standard leak testers were used for evacuating and measuring the leak. These machines are however designed for laboratory use and have many disadvantages in production environments:
- Speed of evacuation.
- High maintenance costs.
- Sensitive to external dust.
- Sensitive to powder carry over to the mass spectrometer.
- High heat development from built-in pump.
- Not an industrial design.
- Components are difficult to access.
- No opportunity to choose between different models with variations in suction capacity or type of pre-pump.
Systematic Vacuum leak detection system
Systematic Vacuum has looked at the existing method again and has concentrated on the disadvantages of the current system. The result is an inline leak tester for continuous production. The principles of measuring and analysing are the same. A mass spectrometer for helium is still used, an ideal gas for detecting leaks. Only a small percentage is present in the environment so there is little disruption from ambient influences. The difference is that the process of helium detection is split into a particle current – bypass system, the result being that a large amount of The questions are immediately overcome.
The mass spectrometer module stands in a stainless steel casing and is therefore less sensitive to ambient dust. The pre-pump stands separately from the mass spectrometer module which creates flexibility in the choice of pump type, low heat development, easier maintenance and less sensitivity. The mass spectrometer unit and the pre-pump are built as one unit on a stainless steel frame and all components are integrated. The whole thing is constructed as a high quality industrial system. Service-friendly and robust.
Characteristics – advantages
- Shorter cycle times.
- Long lives.
- Low maintenance costs.
- Better measuring values.
- Long term stability.
- Better protection from powder.
- Standard integrated pre-filter with exchangeable insert.
- Standard integrated aeration system.
- Robust.
- Low heat development.
- Flexible pump choice.
High quality technology
A large part of the volume to be evacuated from the dome is bypassed around the mass spectrometer to a specific pre-pressure via a valve system, bypass pipe, pressure recorder and control. The result is that the mass spectrometer is only used in the measuring area for which it is suitable and is therefore not used unnecessarily nor does it have any dust or powder to process. The air velocity in the working area is after all a fraction of the speed at atmospheric pressure.
The bypass system with separate pre-pump prevents all the current having to be evacuated by the mass spectrometer. The module is constantly in the measuring mode and does not need to be restarted for each following cycle. The module is therefore only used for working point where the measuring cycle is much shorter.
Large leakages are detected by the pre-measuring method. This prevents the mass spectrometer from being used for large leaks. The pre-measuring method also prevents the mass spectrometer from requiring a long regeneration time as a result of a high helium load.
All the above mentioned measures together result in a much lower load for the mass spectrometer module. Together with the much more efficient pump choice and construction, this results in a much longer lifespan and more reliable measuring values.
References
Leading manufacturers already make use of the Systematic Vacuum leak detection system. Ask our customers about their experiences. We will be happy to send you additional information and a quotation.