Highly flexible pallet circulation plant to produce solid walls and sandwich walls for BWE Bau in Lemwerder

In 2019, BWE Bau Fertigteiltechnik GmbH, a company of the Zech Group, relocated its Wiefelstede production facility to Lemwerder.

BWE Bau is manufacturing quite different two-dimensional precast concrete elements, ranging from simple solid wall panels to sophisticated façade elements in sandwich construction through to elaborate special elements. The products are predominantly meant for residential construction; however, the dimensions of the pallets also allow for the production of large-sized wall elements for industrial construction.

From a conceptual perspective, it was soon obvious that the new production process should run in a modern pallet circulation plant. After examining and determining the circulation systems available on the market, the company went for a highly flexible plant with a central transportation system.

They found an appropriate production hall on the former airport premises in Lemwerder. BWE Bau awarded a contract to Avermann Betonfertigteiltechnik GmbH & Co. KG for manufacturing, delivering and commissioning of the production plant.

Plant concept with production equipment

The plant is designed for a production with a total of 25 pallets of 10.0 x 4.5 m in size and a load-bearing capacity of 7.5  kN/m². The core component is the central transportation system (CTS) that is centrally positioned between the work stations and serves to transport the pallets from one work station to the next. The transports carried out are not constrained to precisely defined processes, but can be freely selected across the production hall.

The CTS is designed for two fully loaded pallets and runs fully automatically in longitudinal direction – with surrounding Rotoscan sensors illuminating the route. Usually, however, only one pallet is moved that is replaced by the existing one at the work station. This results in extremely short changeover times – without long idle times. Work can be continued on the work stations immediately. A concrete spreader with two exchangeable concrete buckets (see also cover picture of this BFT issue) is designed for the discharge of normal concretes as well as SCC.

Additional machinery is integrated in the plant, including an oscillating compacting system with optional connection of HF vibration energy as well as a tilting station and a power trowel system.

The circulation and process control technology was completely implemented by RIB SAA Engineering GmbH based in Austria. The mixing and batching plant was supplied and commissioned by the Danish mixing plant specialist, Haarup Maskinfabrik A/S.

Conclusion and outlook

The demand for high-quality precast concrete elements in different types and shapes is estimated as being very high in the years ahead.

The strengths of the highly flexible pallet circulation plant lie primarily in the high degree of flexibility such as the parallel production of structural components with quite different processing times. But this is where conventional pallet circulation plants reach their limits, as experience shows. Hence, BWE Bau is equipped with an extraordinarily efficient multi-function system for the production of solid and sandwich elements as well as special elements.

A comprehensive report on the manufacturing plant will be published in one of the next BFT issues.