When it comes to auxiliary dedusting facilities used in tasks such as crushing, grinding, transportation, storage and packaging, compact filter plants installed directly at the source of emissions are becoming an increasingly popular choice.
For these applications, Scheuch offers a complete, finely graded range of filters that are proven in practice, accommodating volume flow rates of 200 to 20,000 Bm³/h. Depending on the space available and the volume flow rate, there is the option of installing filter bags either vertically or horizontally and using filter cartridges. These filter plants are supplied pre-assembled, equipped with bags, and ready to connect – and can come with the option of installed fans and silencers.
The Scheuch IMPULS filter is a high-capacity filtering separator that delivers outstanding cleaning performance combined with an excellent degree of separation. It is used for the dry separation of solid matter, primarily in the extraction of contaminants from machinery and the workplace, as a process filter in material recycling, or for conveyed material separation purposes.
Thanks to the specially shaped twin nozzles on the jet pipe, the pulsed free jet pulls along an envelope of clean gas from the primary compressed air as it makes its way to the injector. The two gas flows are mixed in the injector by means of pulse exchange and, at the same time, experience a significant increase in pressure. This ensures highly efficient cleaning throughout the bag length and filter bags that require cleaning less frequently.
Proven in practice for decades, the IMPULS cleaning system has become a byword for low operating costs:
A plant's ability to demonstrate a high level of safety and reliability is essentially dictated by its key components. The radial fan is one of the components at the heart of every extraction, dedusting, exhaust and flue gas purification, and pneumatic conveying plant. It helps to meet customer requirements with a level of quality that guarantees fault-free operation and excellent performance between maintenance intervals.
When it comes to ensuring availability and operational safety in dedusting plants, conveying mechanisms are just as crucial as fans and filter systems.
All conveying mechanisms can also be used in explosive, dust-laden atmospheres as defined in Directive 94/9/EC (ATEX).
In the cement industry, rotary valves are used as continuous discharge or dosage devices with slight negative pressure/overpressure for air exclusion purposes. The advantages of rotary valves lie in their comparatively low construction size combined with a high, speed-dependent conveying output, their ability to be used in a wide range of temperatures and with various pressure differences, and the relatively low energy costs associated with them.
Tube-type and trough screws are used to continuously transport bulk materials, at throughput volumes of 2 to 500 m³/h and with screw diameters between 200 and 1000 mm.
The longer the material conveying path and the higher the quantity of material that needs to be transported, the more sensible a choice high-pressure systems become. The main components of these are a high-efficiency rotary blower plus a rotary valve and an injector. Together, they ensure efficient conveying even when dealing with significant material quantities. High-pressure systems are ideal for use with conveying quantities of 1 to 100 t/h, conveying systems of up to 1500 m in length, and nominal widths between 88 and 500 mm.
Material loading stations consist of a rotary valve with an injector directly attached to it. The rotary valve loads the material into the pneumatic conveying system in a controlled manner. If it needs to handle items that cause wear, the system can also be lined with special materials.
Some years ago, virtually all kiln and clinker cooler filters – as well as some cement mill filters – were the electrostatic precipitator (ESP) type. As these have become unable to live up to growing requirements relating to emission limit values as well as operational safety and availability, however, electrostatic precipitators across the world are steadily being converted into bag filters. Compared with electrostatic precipitators, these ensure significantly lower clean gas dust loads and a consistent degree of separation.
The result is that almost every customer today plumps for the bag filter variety when installing new kiln filters.
Electrostatic precipitator housings are generally very tall in comparison to bag filters, making them ideal for conversion to EMC filters with bags which, over time, have grown to as much as 12 m in length. Excellent use can be made of the available space without the need to extend the housing – saving costs and cutting down on assembly time as conversion can usually be carried out during a scheduled inspection.
Thanks to Scheuch's comprehensive modular system comprising a range of filter head widths and bag lengths, it is possible to find exactly the right module for any housing dimension and thus maintain the required filter area. During the process of planning the engineering work for the conversion, a CFD flow analysis is performed where necessary in order to ensure a uniform inflow for all filter bags.
As an alternative to an gas conditioning tower, gas can also be cooled using a system that injects fresh air. This design is equipped with a mixing chamber where the fresh air is blown in and added to the process gas. The fresh air mixes with the hot exhaust gas, thus reducing its temperature. Compared with gas conditioning towers, this solution incurs lower construction costs; however, since it also involves a higher volume flow, the filter plant must have larger dimensions.
Reliable and compact
Auxiliary units in production areas that perform crushing, grinding and sifting tasks – and in transport, packaging and storage facilities – are subject to significant accumulations of dust, and filter plants for processing this need to be selected and coordinated with the same level of care as would be taken in any other application. Decentralised, compact dedusting solutions installed directly at the source of emissions are becoming today's systems of choice.
The filter units in the IMPULS Compact range are pre-assembled and equipped with filter bags and cartridges at the factory, and are delivered ready for connection to pneumatic/electrical systems.
IMPULS cleaning involves low operating and maintenance costs
Thanks to the use of round bags