20 Questions – Is your metal detection system working?

TWENTY QUESTIONS – What is the best practice for checking metal detectors?

Often industrial metal diction systems are installed on conveyors, pipeline or gravity feed applications.  Once they are installed they tend to be forgotten until an emergency strikes.  To prevent contamination in the food product stream or in any other manufacturing process industrial metal detectors should be tested and used correctly.  Here is a quick check list for any metal detector application.  From this you will begin to understand where your process needs further attention and what areas are working correctly. 

1. Is a metal detector actually being used?
2. Does the metal detector have a self check system set to "fail to safe”?
3. Is an automatic reject system incorporated?
4. For an air operated reject system, is a switch fitted to provide a "fail to safe" situation if the air supply fails?
5. How was the suitability of the system for the application established?
6. Is the product sealed before it is inspected by the detector?
7. If it is not sealed, what is the reason?
8. What precautions are implemented to prevent subsequent contamination?
9. What is the sensitivity standard (ferrous and non-ferrous at least)?
10. How was the sensitivity standard established?
11. Is the standard achieved with the sensitivity sample set in the product so that it passes through the detector on the plane of least sensitivity?
12. How frequently is the detector tested?
13. What was the basis used to establish test frequency?
14. Who is responsible for setting the detector?
15. Who is responsible for testing the detector?
16. Is the test made with metal samples set in the product?
17. Is the reject system tested at the same time as the detector?
18. Is the detector a "computerized unit" providing print-outs of performance? Or if not computerized, is there a written record system?
19. As a minimum are details recorded of Number of rejects,
    1. Frequency and time of system tests
    2. Results of system tests?
20. Where a system test identifies a failure, what action is taken?