Reimelt Henschel MischSysteme: New compounders for the compounding of masterbatches

Reimelt Henschel´s (www.reimelt-henschel.com) presentation at this year´s Fakuma focused on the flexible, efficient and economical compounding of masterbatches for the widest conceivable diversity of applications in the plastics processing industry. At the exhibition were shown the new compounders specially developed for the compounding of masterbatches: the RHC 40 MB featuring a 40 mm diameter screw, a 34D process unit and an output rate of up to 400 kg/h (shown at Fakuma); the other, larger model RHC 55 MB (55 mm diameter screw, L/D ratio 36:1) has an output rate of up to 800 kg/h. Among their special features are the newly developed modular mixing and shear elements for optimum adaptation to the actual processing application and the co-rotating twin screws featuring a high outer to inner diameter ratio of 1.66. The compounders are thus equipped to take a large amount of material in the screw elements, permitting uniform, low-shear plastification and hence negligible power consumption while at the same time achieving high output rates. These features are supported by a newly developed heating-cooling system for the energy-optimized temperature control of the extruder. The modular design of the compounders permits the application-oriented installation of twin-screw side feeders and venting and vacuum domes. A further particularly distinguishing feature of the RHC MB compounder is the control unit, integrated into the main control system, for an intermittently operating mixer. This is used in case of complex formulations where individual batches are pre-mixed economically before being fed into the compounder.

The RHC MB compounders can be used for the compounding of all customary masterbatches, including highly filled pigment concentrates and the widest variety of additive batches, such as anti-oxidative, flame-retarding and antistatic additives, to mention only a few. Compared with conventional systems, the new masterbatch compounders from Reimelt Henschel can achieve, thanks to their new engineering features, the same output at lower torque levels or higher outputs at the same screw speeds. The new energy-efficient drive is equipped with an eight-pole frequency-controlled three-phase motor and permits rotational speeds of up to 750 r.p.m.; an exceptionally short, specially designed clutch coupling operates, without transmission loss, between the motor and the gearbox. This compact drive unit, which has been specially conceived for the masterbatch compounder, contributes essentially to the overall space-saving design of the compounder.

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The twin-screw side feeder, which is without gearbox and hence likewise energy-efficient, is freely and readily positionable along the entire length of the process unit. The version designed for the RHC 40 MB, which is equipped with 38 mm diameter screws with an L/D ratio of 4:1, has a side-feed rate, for example, of up to 250 kg/hour. The hinged extruder head can be swung to one side for fast and easy change of the die plates (all of which have the same outer dimensions) when changing over from one product to another, and also for easy replacement of the screen.

The machine control system is based on the Siemens S7-300 control and specially tailored for the operation of the compounder and, in addition, the operation of a batch mixer. In the case of multi-component compounds, this control configuration permits, the economic pre-mixing of batches before feeding them into the compounder – either via the feed section or straight into the melting zone via the side feeder, depending on the actual requirements of the application. The control system can be easily and intuitively operated; all process-relevant parameters – both for the compounder and for the mixer – are clearly displayed on the touchscreen. An underlying formulation management system can be called up at the press of a button for immediate use by the control system for repeat production runs.
With their 40 and 55 mm diameter screws, these two new compounders, RHC 40 MB and RHC 55 MB, join the range of Reimelt Henschel compounders as special compounders for masterbatch production. For the production of compounds, blends and masterbatches, the RHC series of compounders now comprises a total of six machine sizes with screw diameters ranging from 25 to 120 mm and output rates ranging from 5 to 5,000 kg/h.

Reimelt Henschel MischSysteme GmbH, Kassel, Germany

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