Variable Frequency AC Motor & Drive

Various motor/drive classifications and cooling methods are available depending upon your application and environment. Motor sizing is based on the specific energy and max screw rpm selected for your product or the extruder maximum allowable HP (Kw). Unless otherwise specified the motor is targeted to operate at ≤~80% full load while producing the targeted rate.

Torque Limiting Coupling

A mechanical torque limiting coupling produces an accurate and consistent torque setting ensuring reliable and repeatable torque overload protection. The coupling is test certified at the factory. Mounted between the motor and extruder gearbox, when the gearbox input shaft exceeds torque set value, the torque limiter instantly disengages the driving and driven inertias. A proximity probe is provided to sense coupling disengagement and feedback to the control system.

Gearbox

Designed and manufactured by NFM / Welding Engineers, Inc., gearboxes are produced and assembled in Massillon, Ohio. The gearboxes are optimally designed to transfer power from the main shaft to the auxiliary shaft and to absorb thrust loads generated on the screws by the extrusion process. Gears are helical, case carburized and precision ground for a maximum AGMA rating.

BARREL DESIGN

The WE Series of extruders feature 4:1, 6:1 or 8:1 L/D barrel sections based on the function required for your process. Standard designs include Feed, Closed, Vent, Injection, and Side Feed. Various inserts and ports are also available for optimal vent design, injection and instrumentation.

Standard barrels are manufactured from mild carbon steel and HIP’d with bimetallic bore materials based on your material’s wear and corrosion resistance requirements. NFM offers a variety of barrel options including various base materials (tool steels, stainless steels, duplex, Inconel, etc.), various bore materials (Nitrided, Stellites, Colmonoys, Carbides, etc.) and external treatments (nickel plating, chrome plating, aluminum thermal spray coating, etc.).

PROCESS TEMPERATURE CONTROL

Cored: WE barrels can be cored for cooling to allow medium transfer close to the barrel bores for optimal thermal transfer and precise temperature control.

Jacketed: Barrels can also be jacketed for use with cooling medium, hot oil or steam.

Electrical barrel heaters can also be used if environments allow.

Screw Segments

Non-intermeshing screws are built using adjoining segments allowing for optimization of custom process design. Construction of screw materials are typically stainless steel with Plasma Transfer Arc welded alloy materials to full width of the flight lands for improved wear resistance.

Screws are available in a variety of materials designed for optimal performance in meeting your wear and/or corrosive resistant requirements.

Screw Design

Screw configurations are optimized by our expert Process Engineers based on your polymer and process.  The unique feature of the Non-Intermeshing design allows for matched-flight or offset-flight arrangements to enable improved conveying, mixing, and surface regeneration.

Mechanical Filters

NFM / Welding Engineers’ Mechanical Filters consist of two precision toleranced screws whose flight orientation is such that they pump materials down into the extruder. Engineered to allow removal of liquid effluent from the extruder while retaining the solid polymer particulate, these units are a crucial part to the success of many WE series processes.

These units are selected based on your process’ effluent removal requirements (gallons per minute).

Not only for dewatering and emulsion processes, these units can be utilized to optimize your polymer’s residual volatile levels by allowing late stage water-washing and/or steam-stripping of the polymer prior to exiting the extruder.  This can be key to obtaining those crucial low residual ppm.