Herbst News

Herbst on expansion course

In view of the continuously good order situation over the past months Herbst Maschinenfabrik GmbH has decided to expand its manufacturing capacity in Buxtehude and add a further manufacturing facility in Neukirchen, Saxony; thereby also providing much needed additional job capacity.

Buxtehude will remain the design and manufacturing location for our Central / Stand / Planetary Mixing Units, Rotor-Stator-Systems and the Bowl Discharge System. The existing building has been extended providing additional technical design and office capacity. A special area for the trial runs has been made available and is in operation since May 2008.

Consideration has been paid to the ever increasing demand for not only the single stand alone units but the highly complex mixing systems. The facilities allow for the design and manufacture of the growing demand for larger capacity units to the ATEX Standards and units suitable for Ex-proof areas.

Mixing units for laboratories and small manufacturing plants are part of the positive business development.

New vessel manufacturing site for Herbst

The production started in September 2007 on the new site in Neukirchen (Saxony), where vessels for many different applications are manufactured.

Presently the vessel volumes vary from 2 liters up to 10.000 liters. This volume range covers applications in laboratories as well as in the large-scale production. The vessel can be heated by means of an integrated electric heating system, by an external heating-/cooling aggregate or by steam. The vessels can be designed to operate under both vacuum or pressure. Constructions in compliance with GMP/FDA are possible and also the assistance in setting up qualification documents (IQ, OQ). The material is solely stainless steel.

Besides the vessels, steam provider, evaporator, columns and heat exchanger are part of the production line.

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New research project approved

A new research project in cooperation with the German Institute for Food Technology (DIL) has been launched in January 2008 in order to develop a new horizontal mixing unit.

This AiF-Project will run over a period of 2 years and is subsidized by the Federal Government of Germany.

Encased planetary mixers

Environment and production area of the central mixer are being separated by a sealing from the gear unit (motor and gear). This is due to the special construction of the planetary mixer: the agitator shaft moves on a circular orbit and additionally turns around it’s own axis. Consequently the complete planetary gear or at least parts of it are in the product area, which results in a limited application or none at all in sensible areas.

A newly developed planetary gear allows an application also in sensible product areas by encasing the gear unit completely. There are double linings in the product areas which hinders lubricants to reach the product.

Temperature measuring system with infrared transmittance of the measured data.

One of the most frequent tasks in mixing processes is measuring the product temperature; often of importance is the almost exact measuring of the process control, whereby the positioning of the temperature sensor in the mixing bowl plays an essential part. Generally the temperature sensors are stationary and being brought into contact with the product through the bowl bottom, the bowl jacket or the bowl hood. Especially middle to high viscous products can cause problems, because no representative measuring data can be evaluated of the height of the mixing bowl due to the varying temperatures. Even the flow pattern of the stirrer can influence the locally registered temperature. Furthermore, a temperature difference between bowl jacket and bowl middle can be registered. One can achieve an improvement by operating several temperature sensors.
The optimal temperature measurement can be obtained by moving the sensor through the product during the mixing process. This is the case for example with planetary mixers. The sensor and a transmitter are integrated in the stirring tool or on the wall scraper. The movement of the sensor through the product results in an optimal heat exchange and a representative product temperature.The transmitter is located above the product surface and several infrared diodes transmit the measuring data contact free to the receiver. The transmitter is operated by means of a battery with a life duration of 3 years. The normal measuring range is between approx. – 55 to + 125 degrees Celsius. The standard resolution is 0,125 degrees Celsius. In practice the measuring systems has achieved excellent results. Even product deposits on the sensor unit, i.e. creams, did not affect the transmission of the measuring results.Even on existing mixing units this temperature measuring system can be installed later, it’s instrumentation and control technology can be supplied and fitted individually to suit the specific mixing process.

Development of a new high viscous mixer

In October 2004 the Federal Ministry of Economy and Labour has granted us financial resources for a research project. The operating period of this project is two years and is being processed in co-operation with the German Institute for Food Technology in Quakenbrück. The objective is the development of a new mixer, which enables the processing of difficult and shear sensitive formulas in the high viscous range.This will be processed with a double planetary mixer, where both mixing tools are dependant from each other with respect to revolutions and rotation speed. The requested electric drive is to be developed in connection with a brand new sealing unit, which complies with the special demand in sensitive production fields (i.e. pharmacy, food industry).The heat transmition behaviour is to be optimised by means of electrically heated mixing tools. The project will be closed after completion and testing of a prototype, which indicates an optimised process behaviour, especially for lumpy and shear sensitive products of the food and pharma industry.

Homogeniser with integrated slot adjustment

Already in October 2001 we received the allowance notification from the Federal Ministry of Economy and Technology for a two years research project, which deals with the development of a new mixing and dispersing unit with a product specific energy and shearing record.This project was also accomplished with the German Institute for food technology in Quakenbrück.The project work to characterise the influence of revolutions, direction of rotation, geometry of the shearing zone (rotor and stator) on the emulsifying result and the resulting throughput led to developing an adjustable dispersing unit. A rotor-geometry with only three conveyor elements proved itself during the experimental tests. The applied triangle elements and an optimal emulsifying reaction resulted in a higher conveying capacity. The stator in the dispersing unit was a splitting system with two concentric rings.