Coperion twin screw extruder STS Mc11

Chinaplas 2017 - New involute extruder screw elements and further developments

Stuttgart, April 2017 – For the first time, at this year’s Chinaplas (May 16-19, 2017: China Import & Export Fair Complex, Pazhou, Guangzhou, PR China) Coperion GmbH, Stuttgart, Germany, introduces new involute screw elements for its high-end extruder series ZSK and its new pelletizer "SP treasure”, an innovative, cost efficient strand pelletizer exclusively tailored to the Chinese market.

On its booth 5.1R01 in Hall 5.1 Coperion will present twin screw extruders ZSK 26 Mc18 and STS 65 Mc11. Also on display are a highly accurate Coperion K-Tron quick change twin screw feeder outfitted with ActiFlow™ bulk solids activator and the unique Electronic Pressure Compensation (EPC) system for loss-in-weight feeders, the K-ML-BSP-150-S Bulk Solids Pump (BSP) feeder for granular materials, Coperion’s dual channel diverter valve WZKC for powders and granular products and a CRD rotary valve.

New ZSK extruder screw elements for higher throughputs

To significantly increase throughput rates of its first-class ZSK extruder series, Coperion has developed special involute screw and kneading elements with a new and patented* cross section design. These screw elements are ideal for highly-filled recipes (70-85% CaCO3, TiO2, mainly based on PP/PE and 20-50% talc for automotive grades) for which the dispersion rating and the incorporation of the filler represents a limitation. Besides higher throughput rates, these involute screw elements ensure higher loading of filler, better dispersion and homogenization, lower energy consumption (SEI in kWh/kg) and a significant increase in profitability.

Comprehensive tests at Coperion’s test lab in Stuttgart, Germany, showed a remarkable throughput increase depending on the recipe. For example, when processing PP and 70% CaCO3 on a twin screw extruder ZSK 58 Mc18 the new screw elements achieved a significant throughput increase from 550 kg/h to 900 kg/h. Similar results have been reached when processing PE with 80% CaCO3 on a ZSK 92 Mc18. In this case thoughput was increased from 2.200 kg/h to 3.000 kg/h.

State-of-the-art technology for highly accurate feeding

Coperion K-Tron will exhibit a highly accurate K2-ML-D5-T35/S60 Quick Change feeder at Chinaplas, featuring the ActiFlow™ bulk solids activator and Electronic Pressure Compensation (EPC), paired with a 2415 vacuum receiver for reliable automated refill. The T35/S60 Quick Change feeder (QC) is designed for applications requiring quick changeover of materials and convenience of fast cleaning. The QC feeder allows for the removal of the entire feeding module with screws in place for replacement with a second unit. The removed feeding module can then be transported to a cleaning facility for further disassembly, cleaning and prepped for another material.  Twin and single screw feeding modules are available. Single screw feeding units handle free flowing powders, granules, pellets and other non-flooding materials, while twin screw units are ideal for floodable powders and more difficult, sticky or hard-to-flow materials. The highly accurate D5 platform scale features Smart Force Transducer weighing technology to ensure exactly the correct amount of material is fed into the process, maximizing end product quality and minimizing waste.

The ActiFlow™ smart bulk solids activator offers an innovative method to reliably prevent bridging and rat-holing of cohesive bulk materials in stainless steel hoppers without internal hopper agitation. ActiFlow is a non-product contact device, consisting of a patent-pending vibratory drive and intelligent control unit, designed specifically to work with Coperion K-Tron’s line of gravimetric loss-in-weight feeders. Together with the ActiFlow Control unit, it continuously activates the material inside the hopper with an optimized frequency and amplitude, without exerting any mechanical force on the bulk material. 

Coperion K-Tron’s unique Electronic Pressure Compensation (EPC) system for their high-accuracy loss-in-weight feeders offers an economic alternative to complex mechanical solutions. The main advantages of the EPC system include improved accuracy and reliability as well as lower initial cost and easier installation compared to traditional mechanical pressure compensation systems, which are sensitive to structural factors and machine alignment and may therefore be intricate or even unreliable. Retrofitting options for existing feeders are available. EPC can be installed on a majority of Coperion K-Tron gravimetric feeders in almost any application and all industries.

The Series 2400 vacuum receivers are ideal for reliable automated refill of both volumetric and gravimetric feeders as well as other applications, and can be used for powder, pellet, regrind and granular materials. The design includes a variety of discharge valve types including gravity flap, orifice slide gate and butterfly valve. Series 2400 powder and pellet receiver models are available in carbon steel (painted), stainless steel or aluminum. Each receiver has a stainless check valve to allow multiple receivers to draw material from a common conveying line. All models feature quick connect clamps for easy cleaning and filter maintenance.

Bulk Solids Pump (BSP) for gentle feeding of free-flowing pellets, granules and friable bulk materials

Also on display, Coperion K-Tron’s K-ML-BSP-150-S Bulk Solids Pump (BSP) feeder which is a unique alternative for gentle feeding of free flowing granular materials. The BSP feeder does not use the usual screws/augers, belts or vibratory trays to convey the material. Instead it utilizes positive displacement action to feed free flowing materials with astounding accuracy, offering uniform discharge, consistent volume and gentle handling. The BSP feeder has vertical rotating discs that create feeding ducts. Material moves smoothly from storage hopper to discharge outlet through a “product lock-up zone”, achieving true linear mass flow. With no pockets or screws and only one moving part, the compact feeder is cleaned in seconds, making it ideal for applications with frequent material changes. The BSP-150-S feeds from 34 to 6700 dm3/h [1.2 to 237 ft3/h] using five feeding discs to create four feeding ducts; it features a stainless steel feeder body and uses a stepper motor. Two additional models are available for smaller feed rates.

Twin screw extruders ZSK 26 Mc¹⁸ and STS 65 Mc¹¹

As a representative of its high-end extruder series ZSK, Coperion will exhibit the laboratory extruder ZSK 26 Mc18 with 26 mm screw diameter at Chinaplas. The ZSK 26 Mc18 has a simple design, it is operator-friendly and easy to clean. It is suitable for the development of formulations, for conducting sample compound trials and for the production of relatively small batches at up to approximately 180 kg/h. The ZSK 26 Mc18 is a mobile unit and requires only a minimum of floor space as the control cabinet is integrated into the base frame of the machine.

Also on display is an STS 65 Mc11 with 65 mm screw diameter. It features a specific torque of 11.3 Nm/cm3, screw speeds of up to 900 rpm and proven Coperion extruder quality. Furthermore, the series offers an extremely appealing price/performance ratio. With masterbatch processing in mind, Coperion has equipped the STS Mc11 twin screw extruder with new features that significantly improve the system’s handling and ease of cleaning. The STS Mc11 now has a new manifold with coaxial solenoid valves in order to increase operational reliability. To make it even simpler to work at the machine, Coperion has revised the heat insulating hood in a way that enables easy access to the process section and easier cleaning as well. Quick connections ensure that the hopper can be replaced conveniently. To prevent vibrations during operation, the STS Mc11 series now has an innovative, torsion-resistant base frame similar to the one in the ZSK series. It delivers smooth operation and increases operational reliability, therefore extending the extrusion system’s service life. The STS 65 Mc11 presented at Chinaplas is equipped with a Coperion K-Tron T35 Volumetric Twin Screw Feeder – an economic and reliable solution for feeding powders into the process.

*Patent: EP 2 483 051 B1