Help with screw conveyors - basic sizing, wear protection

[MartinLe]

Hey all, I'm specifying a screw conveyor system for powdered activated carbon and need to establish sensible lower bounds for size and material choice. All transport is horizontal and short distances.

Size: I have 150kg/h, ~300l/h - at 150mm, and assuming the conveyor will be half filled, the medium would need to move at about 1 cm/s - this feels low but sensible for me (but I don't know why). Comments?

The inside of the conveyor will be an ex hazard zone. Under different circumstances, I would call for PE wear slips along the through, I can't do that here because of possible static electricity. Through will be in 1.475 most likely, am thinking simply black steel for screw - any help with material choice for the screw is appreciated.

 

[robyengIT]

wear protection : what about PTFE (teflon, fluon, algoflon, hostaflon, guaflon ?

 

[MartinLe]

PTFE appears to be a good insulator, against static electricity I'd need conductor?
But I've just seen that conductive PE exists (PE-el), not sure if suitable as wear protection since it's stated to be soft (

http://www.senova.com/en/products/technical-plastics/senolen-r-pe-el).

To add:
The other question is if i have relevant wear at all - slow moving auger, little weight (150mm diameter, short length (1-2m)... ) - how to estimate wear?

 

[EdStainless]

You don't need conductive plastics, just static disapative.
There are many options, because static suppression is a huge deal in electronics manufacturing.

Have you tried looking at sizing from companies that make these?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[Compositepro]

A vibratory conveyor would be a good good option, and would be gentler on the material and avoid wear concerns. A screw conveyor could also work fine. Do not use wear strips. There should be no metal to metal contact anywhere. Wear strip will just contaminate your carbon. Any small gaps between moving parts will just tend to crush the carbon into dust.

 

[MartinLe]

One supplier of dosing system states that vibratory feeders will compact the PAC into a solid cake, hence srew conveyors or fluidization by air. The PAC is powdered already (not granulate!). The hint about wear strip and contamination is noted!

Different manufactuerers of dosing stations suggest slightly different sizes (in the 150 - 200 mm range).