Savings in electricity costs with modern, intelligent exhausting technology

The company Vetter Möbel GmbH in Dessau, specialized in furniture production as well as in manufacturing and assembling complete interiors as well as kitchens for the private and commercial sector.

1920 founded by the Master Carpenter Paul Vetter, the family business has continuously developed and has today, led by the owner Frank Vetter, 20 permanent employees and trains 4 apprentices.

During this development, investments were made not only in a new production hall and a new exhibition wing and an administrative wing as well as in the expansion of production capacities, but also in a new exhausting system.

The requirements for the new exhausting system can be summarised as follows:

  • machines to be connected: 12
  • maximum air flow to exhaust all processing machines: 26,200 m³/h
  • simultaneously working factor: approx. 65%
  • maximum exhaust air volume (incl. reserve capacity): 17,000 m³/h
  • mode of operation: discontinuous
  • air recirculation: 100%
  • chip disposal: container
  • installation of the filter system near to the building
  • quiet operation and
  • best possible energy efficiency

SPÄNEX has already delivered the first exhaust system in the early 1990s, which was extended in 2004 by a large dust collector for the extraction of the CNC machine.

After an intensive planning and coordination phase with the owner, a solution was presented which corresponded to the requirements and was energetically convincing, so that the company Hopert & Klinzmann in Haldensleben and SPÄNEX got the order for the delivery and assembly of the new exhaust system.

The equipment delivered is characterized by the following features:           

  • compact filter system with integrated, speed-controlled suction fan, consisting of 4 modules. The individual modules are completely pre-assembled in our factory, so that they only must be assembled and screwed together on the construction site with the help of a crane. This leads to short assembly times. The filter casing is adequate to the fire resistance class EW 90, so that the filter device, as required, could be placed near the building.

 

Module 1: Sound-insulated fan cell with built-in speed controlled centrifugal fan

The direct-driven centrifugal fan built into the fan cell has an efficiency of 81% in the design point, so that for the maximum exhaust volume flow and the required pressure only a motor power of 22 kw is required.

The fan cell is lined with soundproof mats, so that even in full-load operation hardly any noise can be perceptible. Additional external silencers are not required.

Module 2: Filter cell with vibration-cleaned filter hoses

The high separation rate of the tested filter material ensures a residual dust content in the return air of < 0.1 mg/m³, so that the exhausted air can be returned to 100% into the working rooms.

The filter hoses are automatically cleaned by vibration during work breaks. The process is not only effective but also gentle, so that long life for the filter hoses is achieved.

The heat recovery effect, achieved by the 100% air recirculation, is remarkable. In case of a replacement of the maximum exhaust flow of 17,000 m³/h by fresh air, a heat capacity of approx. 200 kw would have to be held available at a deepest outside temperature of-15 °c and a room temperature of 20 °c (layout condition). Even with the use of a fresh air supply unit with heat recovery and a heat recovery rate of 60%, still a heating capacity of 80 kw would be required.

Module 3: chip buffer container with automatically controlled discharging unit and rotary valve

In the container of the filter unit the separated chips are collected. The container volume of 4 m³ is used for the buffering of the material, so that the discharging unit with rotary valve and conveyor screw must only be operated sporadically. The buffer volume of the container also makes it possible to change containers without problems.

The chip material, discharged out of the container, is transferred to a conveyor screw via the rotary valve, transporting the material into a container. Due to the special arrangement of the screw, the container volume is almost completely used, since no cone formation occurs. The function of the screw is monitored by a special safety technology.

  • exhaust pipework system consisting of three groups
  • The group distribution of the pipework system makes full use of the saving potential of the speed control. Two machines are extracted individually. The rest was combined into one group.
  • Return air duct with switching possibility for waste-air operation and fresh-air suction.  
  • Electric switch unit for the complete system with speed control for the exhaust fan via a frequency converter.   

If you summarize the result achieved by the new exhaust system, you can see: more effective exhausting at lower power costs.

The decisive contribution is made by the speed control. By the clean air-side installation of the fan (vacuum technology) and the thus possible use of special running-wheels with higher efficiencies, already a profitable saving effect is achieved compared to the old plant. The greater part, however, comes from the speed control, which, depending on the operated machines, only provides the really needed exhausting power.

The current operating data results in a medium power requirement of approx. 12.4 kw after a period of approximately 2 years. In other words, averagely only about 60% of the installed motor power of 22 kw is required.

In other words, the investment in modern and intelligent exhausting technology pays off for the company Vetter and makes an important contribution to the reduction of operating costs. Other important aspects for the company are the quiet operation and the simple and comfortable chip disposal.

 

 

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