Screw Conveyor Typical Applications
Kase Custom Conveyors has extensive experience in the proper design of bulk material handling equipment for specific applications. Our engineering staff includes numerous degreed engineers from various disciplines.
Examples of applications where such experience is required include:
- Corrosive Products - Screw conveyors must be fabricated from alloys not affected by the corrosive product. Typical materials of construction for corrosive products are 304, 310, 316, 410 and 430 stainless steels. Also, high nickel alloys such as Inconel, Monel and Hastalloy may be used.
- Abrasive Products - Screw conveyors must be fabricated from abrasion resistant alloys when handling abrasive products. Typical materials of construction are AR235, AR360, AR500, cobalt based or chromium carbide based hard surfacing materials. These materials are harder and tougher than A36 carbon steel for resisting abrasion. The carrying face of the screw may be hard surfaced with a weld-on hard surfacing material. Lining of all surfaces in contact with the product with rubber of special resins also reduces abrasion. It is also very important to reduce the trough loading and the speed of the screw conveyor when handling abrasive products.
- Hygroscopic Products - Screw conveyors must be sealed from the outside atmosphere. In extreme cases, it is necessary to provide jacketed troughs or housings with an appropriate circulating heat transfer medium to maintain the material at an elevated temperature. Purging of the conveyor with a suitable dry gas is also used in some installations.
- Products That Emit Harmful Vapors or Dusts - Screw conveyors must be sealed to contain the harmful vapors or dust. These may be safely handled in dust-tight U-troughs or tubular housings. Special shaft seals may be required.
- Products That Emit Explosive Dusts - Screw conveyors may be fabricated from non-sparking materials. Screw conveyors must be sealed to contain the harmful vapors or dust. These products may be safely handled in dust-tight U-troughs or tubular housings. Special shaft seals may be required. Exhaust systems are also advisable for the removal of explosive dusts.
- Products Subject to Packing - Screw conveyors may utilize ribbon flights, mixing paddles, cut flights or cut and folded flights to breakup products that tend to pack. Larger inlets and discharges may be required in order to provide a larger area for the product.
- Products Subject to Fluidizing or Aerating - Screw conveyors may utilize short-pitch close tolerance screws and tubular housings to reduce the possibility of product flowing around the screw. Also, the screw conveyor may be inclined to reduce the head pressure of the product. This condition may be used to advantage in some installations by declining the screw conveyor toward the discharge end.
- Products That Degrade - Screw conveyors for handling products that easily degrade are typically oversized and operated at reduced speeds. The trough loading is also kept to a minimum.
- Products at Elevated Temperature - Screw conveyors may be fabricated from high temperature alloys depending upon the operating temperature. Special consideration is required for handling thermal expansion of the screw and housing. High temperature seals and gasketing are required. Extensive industry specific experience with “exotic” alloy fabrication that includes all stainless steel grades, including 254SMO, Hastalloy, Inconel, Alloy 20, Monel, etc. (pipe, plate and overlay).