Check out this product. I have heard many success stories.

Gary Blenkhorn

http://www.liquidheat.com/test.html ■

Dear Stefan,

I recommend the best first step is to apply ceramic lagging to the pulley surface such as offered by Richcwood and REMA TIP-TOP:

1. http://www.richwood.com/products/pulley.html

2. http://www.rema-tiptop.de/industrie/...8cffb26989b3b2

The ceramic breaks through light ice film where the rubber does not. Take care and not allow the broken ice to recycle. Recycled ice needs to be collected and removed such as in a tray with a removal system.

There are conveyor pulleys working down to -50C. At extreme low temperatures (< -25C) special engineering needs to be considered due to the polymers physical properties. ■

Dear Stefan,

Would you be more specific about the problem and you conveyor configurations.

For belt slippage on a drive pulley, due to icing, both responses previously given are effective. The liquid heat is a consumable product (which means the user will have ungoing costs), while cermaic lagging is a capital cost item. Unfortunately, neither will provide a cure for what you decribed in your last post.

Without knowing the conveyor lengths involved or the number of conveyors (I presume that it (they) are outside.), the obvious answer is to enclose the conveyors and use a heat source to maintain a suitable minimum ambient temperature. With long systems, this would not be economically feasible. There, the use of cleats may work - but would negate your desire for easy belt cleaning.

Regards, ■

Dear Stefan,

I do not know of any commercially available device for only heating belts. Normally, belts warm-up themselves through running.

In your operation, it appears that you are stopping the belt with material on it and then restarting after the ambient temperature has dropped. If this is indeed the case, you could empty the belt at the end of normal material movement and then conduct a belt warm-up by running it empty for a relatively short period. Your method of using a heater to heat the return strand of the belt should work, or you could use radiant heaters to heat the underside of the carry strand (except rubber is a good insulator and the heating costs could get high). Area heating should also work if the heaters are turned on before the belt gets too cold -- this would keep both the material and belt warm enough for material conveyance.

This is an interesting problem, since the more common situation is with the belt sticking to the pulleys and idlers to create a start-up (break-away) problem.

Regards, ■

Mr. Bauer,

One of my customers in Canada operates a sandwich belt high angle conveyor, handling wood chips, in -40 C temperatures. The bottom belt (conventional open troughed belt) is loaded on the horizontal before the sandwich is formed. Only in the loading area does the material tend to stagnate and slide on the belt during these low temperatures. This is due to frosting of both the belt surface and the chips. They have solved this problem by wetting the belt surface with a glycol and water solution. This is applied just forward of the tail pulley through a wet brush. This method of application allows metering the solution down to a dripping so that the solution is absorbed before reaching the head pulley, precluding excessive wettness that would otherwise add to the mess.

I hope this is helpful,

Joe Dos Santos ■

Stefan,

I understand that the product slips on the belt at the load point. If this is true, do you think it may be possible to place the product onto the belt at the same speed as the belt by using the chute's geometry to such advantage? If the product is loaded at the receiving belt speed, do you believe it will still slip backwards on the incline?

Using the discharge inertia and fall distance to control product onto the belt is something we contnue to preach. Send us you chute geometry and product details. If we can simulate the chute and belt incline slip, we might offer a guaranty of success. Our review and response on potential is free of charge. ■

Dear Mr. Capgap,

The problem of ice building can be welll tollerated by providing a drive unit other than main conveyor drive which will run the conveyor during the non-operating time.This will not permit the building of ice in the conveyor.

Regards.

A.Banerjee ■

Stefan,

Coming from the Northeast our customers frequently have the same problems with product slipping on the belt during frosty days. The best solution we have come up with so far is to "fog" the belt and product with "anti-freeze" or liquid heat. The spray system is on both a temperature and time controller. When the temperature reaches a pre-defined temperature the system starts for another pre-defined time limit. The sytem has been working for 2 years without any problems. Units run in the $2500-$3500 price range depending on belt widths.

I hope this helps.

Kevin Easler

VP

PRC Industrial Supply, Inc. ■