Extrusion Twin Barrels

Flite Technology has over 25 years experience solving twin extrusion barrel wear problems.

Manufactured new twin barrels, bimetallic, nitrided, tool steel or CPM materials.

Twin parallel barrels resleeved full length with Centrifugally-cast bimetallic liners.

Replaceable liners made for segmented twin barrels.

Tangential and non-tangential twin barrels

Twin barrels available with ports, vents, cooling and side feeders.

Counter and co-rotating twin barrels.

From APV Baker and Cranfield University

Functionally Graded Materials
In the areas of corrosion and wear resistance, functionally graded materials can be used to fabricate smart, environmentally tolerant coatings. Functionally graded materials acknowledge that different properties are often required at component surfaces or interfaces to those required in the bulk of the component. This can only ideally be achieved through the selection of alternative surfacing or interface materials. However, the choice of a new surface alloy adds further interfaces that again can be optimised. The net result is a multilayered, or continuously graded surface treatment that offers optimised performance. This use of functionally graded structures to provide smart coating concepts is best illustrated by example.

There are many applications where materials are exposed to a combination of corrosion and wear. Due to changes in the local environmental conditions, different degradation mechanisms may occur across the surface of the component and as a function of time. Therefore, no single coating of uniform composition and structure can offer an optimum solution. There will inevitably have to be compromise to resist the range of environmental conditions. The coating of a twin screw extruder barrel used in the food processing industry is an excellent example of variable wear/corrosion conditions because the degradation mechanisms operating on the extruder barrel are invariably dependent on the product, ingredients and relevant process parameters being used. Degradation mechanisms may include corrosion, surface fatigue, abrasive and adhesive wear, with the magnitude of these processes changing both along the length and around the barrel profile, figure 2. To combat this complex attack, a structured coating has been designed, through collaboration between Cranfield University and APV Baker. The coating has been produced by powder metallurgy and HIP, with the structure and composition varying both through the coating thickness and laterally, to accommodate the localised environmental conditions. The outer layer contains tungsten carbide and various chromium carbides in a nickel-chromium alloy matrix. By varying the proportions of tungsten carbide, chromium carbide and the local composition of the nickel-chromium matrix, it is possible to engineer the desired wear and corrosion resistance. The graded inner zone ensures compatibility with the steel substrate.

Some manufacturers of twin screw extruders

Reifenhäuser Ltd
Buhler Ltd
Battenfeld Extrusionstechnik GmbH, Hauptverwaltung u.Werk
Davis-Standard GmbH
Extrufood
Zhang Jia Gang kiwex machinery Co.,Ltd
Battenfeld Extrusionstechnik GmbH
Krauss-Maffei (UK) Ltd
NFM Welding
Technical Welding Services (Rochdale) Ltd
Bpprocess.com
Nanjing Rubber And Plastics Machinery Plant
PLAMA Engineering GmbH
Telford Smith Engineering Pty