Combination of several dust extractors replaces filter plants installed outdoors

With some extraction systems in the air volume range above 10,000 m³/h, there is the problem that, due to local conditions, the filter systems cannot be installed outside of buildings as required by the regulations. The tried and tested alternative solution of arranging the filter unit indoors and equipping it with flameless pressure relief is not feasible in some cases for structural reasons, so that an alternative solution must be found. Against this background, SPÄNEX has developed a plant concept based on dust extractors which is exemplary especially for applications of the type described above.

With the concept of SPÄNEX depending on the required extraction volume flow, two, three or four dust extractors, each with an air capacity of 10,000 m³/h, form an extraction centre which provides an air volume capacity of 20,000, 30,000 or 40,000 m³/h. This means that stationary filter systems in the specified capacity range are replaced by dust extractors.

The dust extractors, manufactured in accordance with the European Standard EN 16770, have been tested by the DGUV Test, Prüf- und Zertifizierungsstelle Holz (Testing and Certification section for Wood) and have received both the GS mark and the H3 (residual dust content < 0.1 mg/m³) test certificate. This means that all requirements are met in terms of both occupational health and safety.

The following should be noted regarding the main features of the system technology::

Dust extractors

The compact dust collectors from SPÄNEX are complete separation 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 running wheel so that high efficiencies are achieved. Energy-saving motors of efficiency class IE 3 (optionally IE 4) are used as standard, whose speed is controlled by frequency converters to adjust the extraction capacity to the respective requirement..  

Further features of the compact dust extractors are:

  • High suction power
    In order to overcome the pressure losses in the woodworking machines and the pipe system, high suction pressures are available at the suction nozzles of the compact dust extractors.
  • Quiet operation
    The sound insulation is particularly effective, so that the noise levels reach top values. Additional external silencers are generally not required. 
  • Effective filter and cleaning technology 
    The high separation efficiency of the tested filter material used ensures a residual dust content in the return air of < 0.1 mg/m³. The compressed air cleaning system (Jet-Pulse-System) ensures an effective and at the same time gentle cleaning of the filter elements with low compressed air consumption, so that long service lives are achieved.
  • Modern design, compactness 
    The design and construction in conjunction with the use of special filter elements have resulted in compact housing dimensions, so that extremely small installation areas are required with equally low overall heights.

Piping system 

The piping system on the raw air side is planned and designed in such a way that the required extraction volume flows are available at all machines that are individually or jointly extracted, with lock slides being installed in the connecting pipes. The automatic opening and closing of the lock slides is initiated by the control system. At the same time it is ensured that the conveying speeds for chips and dust in the main line are maintained and that no material deposits occur. 

Disposal alternatives

The extracted chips and dust are buffered in the containers of the dust extractors and transferred to the rotary valves (decoupling element) via the discharging units. Via the rotary valves, in turn, a screw conveyor or a pneumatic transport system is fed, which conveys the material either into a container, a silo or a larger container, under which usually a briquetting press is arranged. The briquettes for example facilitate the material handling. The capacity of the briquetting press is adapted to the material quantity, whereas machines with a chip throughput of 0.5 to 2 m³/h are produced by SPÄNEX.

Intelligent control engineering 

The function package of the electric circuit automatically ensures controlled and safe operation of the extraction system. Optionally, the control system can also be equipped with a module for remote maintenance, so that the functionality of the system can be checked by our service department at the customer's request.

A further advantage of this system technology is its energy efficiency.

Due to the speed control, only the extraction capacity that is currently required is made available. The speed of the two, three or four extraction fans is adjusted to the respective requirement situation via the built-in controller and the required value pair of volume flow and suction pressure is achieved. Since the machine utilisation varies and even at full capacity, the individual machines can have different running times, this functionality is particularly important in terms of minimising electricity costs. With pneumatic transport systems, the buffering option of the separated material also contributes significantly to saving electricity costs.

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