1.Prepare standard detectingcard or detecting tube.
2.Prepare a long cloth (towel is the best).
For the old detector, dip the cloth in the water and wring it out, adjust the sensitivity to the minimum, turn on the equipment. Pull the cloth straight and press it on one side of the belt, then erase the dirt. Keep to do it until no dirt. (if the belt is very dirty, please wash the cloth for cleaning or use industrial alcohol or anti-static belt detergent) Then stop the equipment, clean the cloth, wring it out and put it cross the underneath of the belt. At this time, grasp the two ends of the belt and run the equipment for cleaning.
After the cleaning, adopt nine point examination method to examine the sensitivity. Put the standard exam card on the belt and start the equipment. If the equipment is able to warn, stops and belt reverses, it means fine. (The card should be placed in three positions—-A1, A2, A3 on the belt for testing) The picture is as shown below:
Insert the standard card into the middle part of the tube (non-metal article is also fine) and put the tube on the running belt. If the equipment is able to warn, stops and belt reverses, it means fine. (The card should be placed in three positions—-A4, A5, A6 on the belt for testing) The picture is as shown below:
Insert the standard card into the top part of the tube and put the tube on the running belt. If the equipment is able to warn, stops and belt reverses, it means fine. (The card should be placed in three positions—-A7, A8, A9 on the belt for testing) The picture is as shown below:
Through the three steps above, if the equipment is all able to warn, stops and the belt reverses, it means the detector fine. (The diameter of ferromagnetic metal ball in the standard card is 0.8, 1.0, 1.2, 1.5, 2.0mm. What specification of the card is used depends on the tested products’ height, detector’s passage height.) The examination will be done every three hours and the record should be made for customer’s check.
If the examination shows the sensitivity can’t meet customer’s requirement, the sensitivity should be enhanced. If it still can’t meet customer’s requirement after enhancement, suggest to contact supplier or replace the equipment.
Glossary:
Nine-point examination—each point’s sensitivity in the detector is different. The part near to the two ends of the probe is the highest while the middle part the lowest. The method is used to examine the lowest sensitivity. By this method the real sensitivity can be examined. (Note: some manufacturers misguide customer by taking the belt part’s sensitivity as the standard)