Need some clarification regarding the conveyer belt surface test, how to test the conveyer belt surface, currently I’m using resistance meter & connect the crocodile clip on the conveyer belt surface to get the reading, but some of the auditor or customers are requesting the two point probe to test the conveyer belt surface, during the test it is meeting intermittent spec, means the reading is not so accurate, i fill very confuse on this. Which method is correct for the test of conveyer belt surface.
Hello,
Greetings of the day from India to all on this platform.
The test method applicable and used per ANSI ESD S 20 20 for the conveyor belt is ANSI ESD STM4.1 applicable to the work surfaces.
Here, you need to use ;
1.The Resistance meter which shall have circuit voltage of 10 volts (± 5%) while under load for measurements of <1.0 x 10e6 ohms and 100 volts (± 5%) while under load for measurements >/= 1.0 x 10e6 ohms. The meter shall be capable of making measurements from 1.0 x 10e3 ohms to 1.0 x 10e9 ohms.
2. 5lbs x 63 mm dia appx SS insulated probes each -1 pr per ANSI ESD STM 11.11 applicable for Planner surfaces.
The Point to point as well as the Point to ground resistance need to be less 1 x 10e9 ohms .
For periodic compliance verification P-P test needs to be checked as a trouble shooting cross check test if the Rptg ( resistance point to ground) fails to meet the requirement.
The two point probe per testing method ANSI ESD STM11.13 is for Point to point resistance of planar materials( basically miniature surfaces) where per 5 lbs probes ANSI ESD STM 11.11 cannot be used .
Currently, while a test method for the conveyor belt it s not mentioned anywhere per the ANSI ESD S 20.20. , it is as per STM 4.1 /STM11.11 only , as applicable to any work surfaces such as Table tops/ Racks and Mobile Equipment tops ( Trolley).
However, it is likely that there will be a mention on this in the up coming edition of ANSI ESD STM 4.1 as clarified by ESDA in one of the correspondence on clarification sought on various issues.
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I posed this question to Dale Parkin, the chairperson for ESDA working group 4 on worksurfaces. They are working specifically on a technical report on conveyors and hope to have it published soon. He read the original question and wrote back:
"This would depend on what they mean by conveyor belt. Is it one large belt or is it two small edge belts? Is it a two-layer material or a single homogeneous material?
Two different types of tests and two different types of materials
However, in reading what it is written I am taking it as they are talking about small edge belts.
When clipping a crocodile clip to the edge belts you are in contact with both the top and bottom surface. If it is a two-layer belt, the bottom side is the conductive side and that is what you will be measuring only and not the top side which makes contact with the product as it is a higher resistance. Therefore, this is not recommended.
The two-point (probe) would be better as you are only testing the top surface. However, then you would need to test many locations and make sure there is a support under it so you get a flat area for the probes. Also, you will need to test from top surface to ground as well.
The TR we are looking at uses a metal plate (for 2 belts). This plate will be placed on the conveyor, with one side having an insulator under it that makes contact to the other belt. Then you would flip it around to test the other belt. This is using the metal plate in conjunction with the electrode that is used for work surfaces and flooring, by placing the electrode on the plate and the other lead to ground."
I hope this helps