Mann+Hummel ProTec: Precisely dosed drying

In the central drying plant two SOMOS® D 600 dry-air dryers are in operation: One of them supplies dry air to eight drying hoppers with a volume of 400 l each (at the back of the platform) and the other to two 1,200 l hoppers (front). The online throughput-measurement at the two 1,200 litre hoppers (bottom left) ensure to achieve a continuously even drying result in both of the hoppers.

HellermannTyton using integrated SOMOS® technology
HellermannTyton is using efficient and cost-effective SOMOS® technology from MANN+HUMMEL ProTec to dry some 100 materials for 68 injection moulding machines in line with its needs. The online flow measurement of two central drying hoppers is a special feature of this.

HellermannTyton has rounded off the material drying concept for its production site in Tornesch near Hamburg with its latest acquisition, a SOMOS® D600 dry air dryer with two 1200-litre hoppers. This is being used to prepare a PA type used in large quantities for injection moulding. A special feature of this central drying system is online flow measurement to achieve a continuously even drying result. The company uses both local and central drying systems aligned to the product and production spectrum.

Materials required in small amounts and changing often are dried with SOMOS® TF machine-side dryers (with integrated conveyor system) at the respective injection moulding machines (left). Photo on right: The materials dried centrally are transported to the machines in materials-specific lines.

HellermannTyton has developed a reputation as a world leader in products and system solutions for bundling, securing, protecting, identifying and processing cables and wires as well as their connection components. Its plant in Tornesch was brought into operation in 2000 and is one of the largest production facilities in this global company group, with 15,000 m² manufacturing and storage space. It produces all kinds of fastening elements for cable bundling systems which are primarily used in automotive manufacture. Part weights range from 200 mg to 400 g.

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Enormously wide range of materials
“We process mostly engineering plastics from PA, POM and ABS to PEEK with clamping forces of 250 to 4200 kN and also the standard plastic PP in small quantities on our 68 injection moulding machines. Polyamides are the main thermoplastics used and there is an enormously wide and diversified type spectrum”, explained Thomas Schrenkhammer, head of the Injection Moulding department. Because of this, there are some 100 different materials in stock in Tornesch which have to be prepared for processing. Around 2500 tons in total were processed in 2009.

Products and system solutions for bundling, attaching, protecting, labelling and processing cables and lines and their connection elements – HellermannTyton has gained the reputation of a global leader with innovations such as cable ties for “tight fit over time” that can be loosened (upper left). Photos: MANN+HUMMEL ProTec/HellermannTyton

With machine operating times per product varying from continuous operation to just three hours a year, the material preparation concept had to be designed to meet these flexible requirements. Frequently changing materials are dried with SOMOS® TF eco machine-side dryers with an integrated conveyor system leading directly to the injection moulding machines (as was exclusively the case until the move to the new Tornesch facility). The types used in larger quantities are prepared centrally with process-controlled drying systems. The first central system went into operation back in 2001. It also boasts SOMOS® technology – a SOMOS® D600 dry-air dryer and eight drying hoppers, each with 400 l capacity for various materials.

Thomas Schrenkhammer designed the conveyor system from the drying system to the injection moulding machines to meet the needs at the Tornesch production facility. Different lines for different materials transfer the dried granules to the production hall where each injection moulding machine can be connected individually to each line. This allows for a high degree of flexibility in deciding whether to operate all machines with centrally dried materials or locally, with the materials being dried using eco machine-side dryers.

Continuous operation with controlled extraction
"Our company has grown continuously over recent years, along with the quantity of material to be processed. That´s why we have now put a second central drying system into operation exclusively for continuously operating machines. We have installed two 1200-litre hoppers for this instead of a single hopper solution. We opted for this due to a height restriction in respect of the hall ceiling for one but also because it allows us to adjust flexibly to our needs”, said Schrenkhammer.

The system is equipped with online flow measurement and again involves a SOMOS® D600 dry-air dryer placed on a platform preparing the dry air. A measuring chamber with a defined volume and pneumatically activated sliders (top and bottom) is attached to each hopper outlet. This ensures that the dried granulate is completely controlled and extracted in precise doses. “This allows us to set up the hoppers to ensure that the material to be dried is held by both of them for the same defined period. The material is neither dried too little nor too much, especially because the hopper level is monitored using sensors. It would not be possible to calculate the drying result if both hoppers were freely outputting into the common suction box for distributing the dried granulate to the injection moulding machines”, explained Schrenkhammer. Thanks to the two-hopper solution, HellermannTyton can also operate the system with half-flow (using just one hopper).

Process safety is decisively supported by the efficient technologies all SOMOS® dryers are equipped with – ALAV, which adjusts the dry air flow according to the actual material flow rate, and Super-SOMOS®, which adjusts the regeneration frequency of the desiccant bed based on the quantity of moisture absorbed. “Our concept and material drying systems are well tried-and-tested. Everything is running stably and reliably around the clock”, summarised Thomas Schrenkhammer.

More Information: www.mh-protec.com, www.hellermanntyton.de

Mann+Hummel ProTec GmbH, Bensheim, Germany

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