USER REPORT Extraction
USER REPORT Extraction centre with several dust collectors Lessmann – the german brush company is one of the leading manufacturers of technical brushes in Europe. Due to an increase in capacity in the wood-working production area, a renewal of the extraction system was necessary. Surface tools „Made in Germany“ have been manufactured at the production site in Oettingen/ Bavaria since 1948. As a medium-sized family business, Lessmann is a producer of surface treatment tools with a clear commitment to Germany as a manufacturing location. More than 240 qualified and motivated employees develop and manufacture technical brushes such as circular brushes or interior brushes for all areas of industry and trade. Only with the know-how and the good cooperation of all departments it is possible for Lessmann to supply „first-class products“ to customers worldwide. The wide product range of wire brushes is distributed through trading companies or directly to industrial customers. As part of the expansion of production capacity, the extraction system for woodworking also had to be renewed. The task submitted to SPÄNEX had several special features: • The required extraction and filter system for an air volume capacity of approx. 40,000 m 3 /h should not be installed outside due to space problems, • The chips produced should be briquetted and used as fuel in the company’s own boiler plant. Excess briquettes should be disposed of. The further requirements for the extraction system can be summarized as follows: • connected working machines: 23 • 100 % air return, • silent operation, • maximum energy efficiency. In several site visits the responsible SPÄNEX regional sales manager, Mr. Rieder, discussed all details. The proposal was made to implement the extraction system by 4 dust collectors, which should be installed in the production hall. After the inspection of a plant already realized (Fig. 1) the customer agreed to this concept, so that a detailed offer could be made, which included the following main components: • Extraction centre consisting of 4 dust collectors with integrated, speed-controlled extraction fans, • Extraction piping system, divided into 4 groups, • Briquetting press with a capacity of approx. 250 kg/h (material-dependent), • Electrical circuit on PLC-basis with 4 frequency converters for the whole plant. The advantages of the plant-technical solution convinced the customer, so that the order for the delivery of the suction and briquetting plant was given to SPÄNEX in 2018. The following aspects are the main advantages of this technical solution: • Interior installation of the extraction unit: The dust collectors, manufactured according to the European Standard EN 16770 and tested by the DGUV Test, Prüf- und Zertifizierungsstelle Holz (GS-sign and test certificate H3) meet all requirements in terms of workers’ health and safety and are approved for installation in the working area. The compact dust collectors of SPÄNEX are complete dust extraction stations consisting of the flow-in/filter chamber, the fan cell and the container part. The fan is arranged on the clean air side and equipped with a high performance impeller so that high efficiencies are achieved. Energy-saving motors of efficiency class IE 3 are used as standard. • Energy efficiency By dividing the piping system into 4 groups, the savings potential resulting from different requirements for extraction capacity can be fully used via speed control. Automatically opening and closing lock slides are installed in the connection lines to the woodworking machines (Fig. 2). The opening and closing of the slides is initiated by the control system and at the same time the need for the required extraction capacity is detected. The speed of the extraction fans is adjusted accordingly via the control system. At the same time, the control system ensures that the minimum conveying speeds for the chips and dust are maintained, so that no material deposits occur in the pipe- line system. • Silent operation The fan cells of the compact dust collectors are lined with sound absorbing mats, so that the noise emission is extremely low. Additional external silencers are not required. • Briquetting The dust and chip material separated in the dust collectors is buffered in the containers of the dust collectors and transferred to the rotary valves (decoupling components) via the discharging unit. The rotary valves feed a screw conveyor which conveys the material into a container under that a briquetting press is arranged. The capacity of the briquetting press is approx. 250 kg/h. This corresponds to a chip throughput of about 2 m 3 /h. The octagonal briquettes produced are conveyed via a transport rail system into the silo for firing in the heating boiler plant. A changeover switch is installed in the transport rail (Fig. 3), so that alternatively, when the maximum filling level in the silo is reached, the briquettes can be conveyed into a big bag for disposal. • Intelligent control The function package of the electric circuit automatically ensures the controlled and safe operation of the extraction and briquetting plant. Resume of the Management Board After almost one year of operation, the responsible managers at Lessmann are enthusiastic about the performance and functionality of this technical solution as well as the energy-saving and lownoise operation. www.spaenex.de 28 No. 3 • August 2020
USER REPORT Warehouse for wooden plate materials Increased efficiency through fully automatic order picking in the sheet material warehouse Drevo Trust, one of the largest suppliers of products for furniture production and interior equipment in the Czech Republic, has commissioned a new warehouse for the storage of sheet materials. It is one of the first automatic sheet material warehouses in the Czech Republic: Storage and retrieval, picking and provision of the orderrelated packages are fully automated. This not only increases the efficiency of the entire storage and order picking process, but also enables a high area utilisation and reduces damage to the goods. The concept of using the advantages of two-stage picking is completely new: A storage and retrieval machine (SRM) handles the storage and retrieval of packages in the warehouse. If a shipping order requires the picking of different individual sheets, a vacuum manipulator has the corresponding articles ready for shipping, whereby several orders can be processed in parallel. Thus, two separate systems put the orders together very efficiently in the smallest of spaces. The warehouse was completed by OHRA, market leader for cantilever racks, in close cooperation with the partner company Köttgen, which supplied the storage and retrieval machines (SRM). In particular, laminated chipboard and worktops in various dimensions and designs are stored in the new central warehouse. In total, the warehouse has space for more than 3,400 of these packages, which can weigh up to 2 tons and are usually 2,800 by 2,070 millimetres in size. From these, the order-related customer packages are picked for dispatch to the end customers and branches of Drevo Trust. The project was fulfilled by OHRA. The market leader for cantilever racks manufactures all loadbearing elements of its racks from solid hot rolled steel profiles. Therefore, they offer a high loadbearing capacity and a particularly slim design, prerequisites for the high-density storage utilisation in the new 11-metre-high Drevo Trust warehouse. OHRA’s many years of experience in the implementation of fully automated wood storage systems also was an advantage. The racking specialist was involved in the design of the warehouse and worked closely together with the Köttgen company, which supplied the storage and retrieval machines. This way, the interfaces between the racking system and operating devices could be precisely coordinated and smooth automatic processes are guaranteed. OHRA supplied a total of seven double-sided and two single-sided, 57-metre-long cantilever racks. The eight aisles are served by two storage and retrieval machines. They store the packages chaotically, then transport them to a transverse shelf installed on the front side of the rack aisles. A structural steel platform also provided by OHRA is directly connected to this shelf. An automatic vacuum system is installed on top, which holds the required individual sheets ready in parallel stacks for up to five customer orders. The fully assembled customer orders are then transported by the storage and retrieval machine to the transfer point, from where they are finally removed by a forklift for loading. The entire system is controlled by a WMS and automation system, which was developed by Drevo Trust. In this way, customer orders are picked automatically in a two-shift operation. Compared to the storage systems previously used by Drevo Trust, the new warehouse offers a significantly better use of space, while damage to the goods and the time required for picking have been significantly reduced. In addition, the picking quality has improved and errors in the compilation of customer packages have been minimised. The new warehouse went into operation in mid-2019, and Drevo Trust has already commissioned OHRA to build additional warehouses. Drevo Trust www.ohra.de The headquarters of Drevo Trust A.S., founded in 2003, is located in Frýdek-Místek, Czech Republic. The wood trading company offers carpenters, joiner and do-it-yourselfers more than 20,000 articles for furniture construction and interior decoration. They are available through the 25 branch stores or through the company’s online shop. No. 3 • August 2020 29
