Janssens was founded in 1928 as a building materials merchant and transport business under the name of Jos Janssens Heymans. Today, the company is trading as NV J. Janssens en Zonen . At its production site in Brecht, Belgium, it mainly manufactures hollow and solid concrete blocks and ready-mixed concrete, achieving a total annual turnover of about 45 million euros. During the past three years, sizeable amounts have been invested in trucks and machinery and in a concrete plant. When Janssens also decided to set up a new production line, the company entered into talks with several potential suppliers. Hess Group was contracted with the supply of the line after thorough visits and comparisons of various plant designs. This choice was preferred mainly because of the perfect adaptation of the plant layout to the existing factory building and the technological features of the block-making line.
New block production line
Concrete continues to be supplied from the existing batching and mixing unit. The Schlosser mixer discharges the concrete onto a belt conveyor supplied by VHV-Anlagentechnik . This conveyor feeds the concrete directly into the storage bin of the Hess RH 2000-3 MA block-making machine, which is a true highlight of the Hess product range. Boards are 1,400 by 1,300 mm in size and provide a production area of 1,300 by 1,250 mm, which enables the manufacture of 18 blocks (each measuring 200 by 400 by 200 mm) per cycle. When manufacturing these products, the machine achieves a cycle time of about 13.5 seconds.
Blocks are manufactured on Duroboard production boards supplied by Assyx . The machine transfers the products to the V belt conveyor that moves them into the elevator unit. The latter is designed for a maximum load of 14 t and has been adjusted to the height of the factory building by providing nine levels with two production boards per each level.
Laser-based monitoring of finger car travel
The finger car with turning unit transports the products to the Rotho rack system. All movements of the finger car are monitored by a laser system. To ensure good visibility under all conditions, the system is operated manually via a radio remote control similar to those used for cranes on construction sites.
After curing, the concrete blocks are moved into the lowerator unit. A parallel lifting process is used to separate the boards from each other in the lowerator. An electrically driven latch conveyor transports the products to the cuber. From there, the empty boards are moved on to be cleaned, sprayed and turned, and are subsequently returned to the board magazine of the machine. A board buffer facility is connected to the system via a transfer car with integrated chain conveyor.
The servo-controlled cuber takes the products off the production boards and places them on the slat conveyor. Servo drives enable the control of the lifting, linear travel and turning movements of the cuber. The clamp is operated hydraulically; it is capable of turning the hollow blocks by 180o to avoid the manual turning of products during the handling process.
The slat conveyor transports the block packages to a Cyklop horizontal strapping machine. In the next step, the finished block packages are transferred to the loading area.
Timely production start enabled
The production line is operated from a central control room, the power cabinets are located on a second level above this room. The line uses Siemens S7 controllers and Siemens WIN-CC controllers for visualization purposes. It is equipped with a mobile panel for quick and easy manual operation. An Internet-based modem service enables troubleshooting in the event of disruption or failure and/or remote plant maintenance.
This project demonstrated that close collaboration between the client and the supplier is crucial to achieve a satisfactory outcome. Both parties involved are pleased about the adherence to all set deadlines despite the extremely bad weather conditions. As a result, the production line was handed over to the client and commissioned in a timely manner.
Despite the current crisis of the construction industry, the owners of NV J. Janssens en Zonen are adopting an optimistic view with respect to the future of their company, aiming to expand the family-owned business further.