in normal day shifts – 5 days a week.
Drying and baking process:
7 days a week – 24 hours a day.
a total of 40 employees (production, technical service and office).
The clay that Steenfabriek Engels wins for the production of masonry and street bricks in the floodplains of the Meuse in part comes from its own clay quarries.
Maasklei is irony and therefore the distinctive red color is created after baking. Several times a year, new clay is supplied and the stock depot is built up in layers, after which the entire bump is systematically splayed to achieve as homogeneous a composition as possible.
During the construction, clay samples are taken daily from each layer and examined and checked for composition in a laboratory.
From the clay depot, the clay is brought into the production process. This process is fully automated and consists of clay preparation, a hand-molded installation at the Helden location, a mold press at the Oeffelt location, a room drying device, a stacking machine, the tunnel kiln and a discharge with an automatic packing device.
Clay preparation and molding sand
With the loading shovel of the clay hop, the clay is brought inside into a disposable (large storage bin). There is a storage funnel for the molding sand. From these storage bins clay and sand are dosed in the process. An electromagnet is suspended above the clay supply belt to remove any metal parts from the clay.
In the cucumber corridor and clay rind, the clay lumps are reduced and water and steam are added automatically as required. Further mixing takes place in the clay mixer. The mold sand dryer, a rotating long drum, ensures dry mold sand.
The most important in the ‘stone press’ are the mold containers. These are sprinkled under the press with molding sand to prevent sticking of clay. This sand also gives the sanded appearance to the stone. The press boiler is located above the press, from where a brick mold is filled with clay 24 times per minute. After first removing the excess clay with a scraper tape, 4 steel drying plates are placed on the molds at the same time. The mold rotates 180 degrees with the plate and the wet stone bags under the machine, out of shape, on the drying plate. The stones thus formed come in a collection rack and are then transferred to tumble dryers. The mold containers themselves are again rinsed clean and sanded and the entire process repeats itself.
Dust and sand are extracted in various places, which is collected in special silos and reused as much as possible. In the water basin outside, the rinsing water ends up in the stone press. Sand and clay particles settle in the sloping tank and are regularly scooped out with the loading shovel. The water then flows to a special pond to allow the fine clay particles to settle. The water is then pumped back and ends up in a separate deep water basin, from where it is reused again. Rainwater from the roof is also collected and used.
The drying of the ‘wet’ greens takes place in drying chambers which are ‘Drying expert systems as much as possible with residual heat from the ovens.
The dryer has a number of drying chambers containing drying carts with the still wet stones. Drying the wet stones takes at least 2 days. If more time is available, drying is slower to save energy. The heat for drying is residual heat from the tunnel kiln, which is supplied through the large pipelines. Additional heat can be added per room with gas burners. Almost 1 liter of water must be evaporated from each brick. After drying, the stones have become about 8 percent smaller.
The dryer cars are driven in and out of the rooms fully automatically. After drying, the stones are pushed off the plates and go to the setting machine via a long chain conveyor. The drying plates go back to the stone press.
The dried stones must still be baked. They are delivered in rows to the typesetting machine, set according to a fixed pattern and then – via various movements – formed into layers, and brought to the setting belt. From this belt the stones are picked up and put on the tunnel kiln cars. On each car there are rows, in special context stacked, stones to stand. The tunnel kiln cars are driven into the warming tunnel, which serves as storage buffer for the kiln.
From the warming tunnel every day fully loaded the fully loaded tunnel kiln cars in the tunnel ovens. The cars slide very slowly through the oven and after a few days they come out with the baked stones. The temperature gradually rises from the beginning of the oven to 1050 degrees Celsius in the middle. This temperature is very different per sorting and color. The heating recipe helps determine the characteristic color characteristics of the stone. Subsequently cooling takes place very slowly until the exit. The floor of the kiln cars consists of refractory bricks to protect the steel frame of the car against the high temperature. There are a total of about 200 gas burners on the side and top of the oven. Furthermore, there are fans, control valves and cooling systems, which together control the baking process. All relevant data are recorded and visible on the screen of the various operating systems. The heat released from the kiln is optimally utilized in the dryer and the combustion gases go via a flue gas purifier to the chimney of 40 meters high. Our tunnel ovens are fired on the “clean” natural gas, whereby constant energy monitoring attempts to bring the energy consumption to the minimum while maintaining the quality of the end products.
- Engels Helden has a kiln capacity of 70 million stone size per year.
- Engels Oeffelt has a furnace capacity of 60 million stone size per year.
Due to the comparatively low lime content and high iron content of the clay used and by the use of specially selected molding sands, beautiful colors are achieved during the optimally controlled baking process in the modern tunnel oven, which retain their originality over the years.
The baked bricks are now removed from the kiln trolleys with grippers and are formed in standard hulo packages of 10 layers high. To this end, the top layers of bricks from the tunnel wagon are first removed. The footstone layers are formed from this. Four layers of stones are placed on each layer of pedestals. All packages can be split and split to make it easier to work on the construction. If desired, the stones can be placed on pallets in packaging foil. This allows the customer to choose between: loose in hulo system / large pallets / small pallets (half high) or auxiliary pallets. After each round, the top of the kiln car is sucked clean.
Transport and delivery
All deliveries are in principle made via the building materials trade.
The sales team can always give you excellent advice in our showroom when making the right choice of stone. It is advisable, however, to include building plans and other necessary information.
Trucks with special cranes bring the bricks to construction sites in the Netherlands, Belgium and Germany. Other export countries require a special packing method adapted for long-distance transport. Ultimately it is the bricklayers on the building, who take the stones for the first time to process.