Looking for heat resistant rollers

[scastillo]

At our facility we use a furnace to clean excess plastic from our extrusion heads. The heads are disassembled into 2-3 pieces each weighing approximately 200 / 250 lbs. The furnace is equipped with a shelf, really nothing more than a heavy steel grate, which slides out to allow the loading of parts. Because of the weight of the extrusion head pieces the maintenance crew have to slide / push / manhandle the pieces into place atop the grate, a process requiring at least 2 men and considerable effort.

What I am looking to do is redesign the grate to include rollers, something along the lines of a gravity conveyer arrangement.

What I am concerned about is the high heat these rollers would encounter. Depending on the amount of excess plastic the extrusion heads could be inside the furnace for a couple of hours or more.

Does anyone have any experience, or suggestions, on rollers that could handle this application?

BTW, I've tried the furnace manufacturer, but they have nothing to offer.

Thanks

 

[arunmrao]

My company specializes in manufacturing heat resistant castings. One of the applications is the roller and roller track assembly. If the grate, is to move over the roller tracks ,standard designs are available from different furnace manufacturers.

Normally if you can machine a few rolls and tracks out of 304 grade material and use it in you application a fair amount of idea can be obtained.

 

[scastillo]

I should add that the furnace reaches temps around 900F.

 

[unclesyd]

We have 9 furnaces that are used to clean polymer coated parts probably in a similar fashion to your setup. All these furnaces are Pyrolysis furnaces, that have no flame and the temperature is controlled at 900F. All the furnaces except one is loaded using wheeled carts on tracks. Some rails others have channels. As these furnace components don't see flame temperatures all the components are CS. We have no problem with CS parts unless they get over loaded. The one furnace we have for flite screws has CS rollers for loading.

Here is some furnace that are similar to ours. all the larger furnaces are loaded by carts on tracks. The tracks have a removable section that allow the doors to operate.

http://www.pcpconline.com/pcpconline/index.php?key=product4

 

[dvd]

Graphalloy makes high temp cam followers and other bearings. Their standard is 750 F, but you should call them to discuss your application.

 

[scastillo]

unclesyd,

The link you provided is from the manufacturer of our furnace. We have the IGG-27F model. Just like in your application, our furnace comes with the cart that rides atop the 2-legged track section. The problem we are having is getting these very heavy and cumbersome work pieces from atop our own maintenance carts and onto the furnace cart / shelf. If the furnace shelf had a series of rollers already installed then it would be a simple matter of positioning the piece and rolling it over.

 

[unclesyd]

We have electric monorails over all the furnaces which allows easy loading of all the furnace carts.
On our next to largest furnace we use an traveling electric monorail to load large sections of bulky jacketed polymer pipe with no problems. On our largest which is located some distance from the operating area we use boom trucks to load and unload the cart.

Also loaded with an electric monorail is the flite screw furnace. On the long flite screw furnace we have both CI and Steel rollers with replaceable shafts. The only problem I can recall was the shafts wearing the supports on each end. This was solved by welding a "U" shape clip made from Astralloy to the support rail for the shafts.

I can't see a problem with using CS for rollers if you will not be point loading any of the rollers. Just make the shafts short to take out a little bending moment.

 

[swearingen]

Have you looked at Hilman Rollers?

 

[diskullman]

The rollers are not the big problem, it's the bearings in the rollers. When I worked for Unique Technologies, we installed Cobra Solid Lubricant in many various standard bearings for furnace applications
check their website

http://www.uniquetechnologies.com

Russell Giuliano

 

[Compositepro]

Simple pieces of pipe make great rollers. I keep a few sections of stainless pipe in my pick-up for moving heavy objects.

 

[patprimmer]

Graphite powder makes a good if somewhat dirty lubricant for high temperatures.

Cylindrical rollers located in channels should need little if any lubricant.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.