WO2001075375A1

WO2001075375A1 - A device for and a method of reducing build-up of dust and particle deposits in exhaust-air ducts

Info

Publication number: WO2001075375A1
Application number: PCT/SE2001/000671
Authority: WO
Inventors: Sidsel Kristiansen
Original assignee: Scandfilter Ab
Priority date: 2000-04-03
Filing date: 2001-03-28
Publication date: 2001-10-11
Also published as: SE0001184L; SE516064C2; AU2001244954A1; SE0001184D0

Abstract

The invention concerns a device for reduction of build-up of dust and particle deposits in exhaust-air ducts. It comprises a filter (1), which is adapted to be mounted on the side of the exhaust-air device (2) that faces the premises. The filter (1), when in its mounted condition, is visibly available from the premises. The invention also concerns a method of reducing build-up of dust and particle deposits in exhaust-air ducts.

Description

A device for and a method of reducing build-up of dust and particle deposits in exhaust-air ducts.

TECHNICAL FIELD

The present invention relates to a device for reduction of build-up of dust and particle deposits m exhaust air ducts.

BACKGROUND OF THE ART

In order to clean air of particles, dust and some gases m a ventilation system filters of various kinds are used. To filter gas, filters comprising active carbon usually are used and to separate particles and dust, filters manufactured from a synthetic material or from glass fibres are used as a rule. Most often, filtration of air takes place immediately following the air intake m order to ensure that the intake air meets the requirements of purity. In the processing industry and m other special cases, carbon filters are used to filter the air to remove gases but normally, air- intake systems are equipped only with particle filters. In the case of the exhaust air, the air is subjected to filtering m exceptional cases only, such as for instance when substances harmful to the health are handled m fume cupboards or m the manufacturing industry if large quantities of dust are generated. The dimensions of ventilation ducts installed m multi-family houses and offices are very small compared to those of ventilation ducts installed m industrial premises, i.e. the cross-sectional area of the ducts is a great deal smaller, with consequential smaller capacity and a larger pressure drop. When the pressure drop increases, the fan must increase its speed of rotation m order to sustain the flow, which m turn means higher energy consumption. In many less sophisticated systems, regulation of the rotational speed of the fan is not automatic and consequently, the ventilation flow becomes too low. In addition, the pressure drop m a duct having a small cross-sectional area is more widely affected by deposits of dirt on its internal faces . In ducts having a considerable cross section, the presence of a brick m principle would not noticeably affect the system. For the reasons stated above it is therefore important to equip ducts with filters and the smaller the cross section of the duct, the more important are the filters.

Considerable amounts of dust and particles are generated m homes and offices, which are precisely the kind of premises that are equipped with the least sophisticated ventilation systems. When the exhaust -air ducts are clogged by dust and particles, the pressure drop increases and the flow drops, and as a result the quality of the air m these premises will be inferior. The problem is all the more serious m multi-family houses and offices, where exhaust-air systems often are installed. To clean narrow exhaust-air ducts is often complicated and m some cases even impossible, and for that reason very expensive. One solution might be to filter the exhaust air directly adjacent the exhaust-air means. Filters of this kind are available on the market today.

In order for them to function, a filter of this kind must, however, be exchanged at regular intervals. A problem encountered m this respect is the difficulty m keeping track of the times of exchange, and m some rooms the filter might not need replacement as often as m others. The opposite problem may occur if the filter is not changed at all, which causes the same disadvantages as when the exhaust air is not filtered. A further problem is that it is a comparatively complex task to change the filters and a specialist is needed to do the job .

SUMMARY OF THE INVENTION

The object of the present invention is to provide a filter which can be changed easily and which makes it easy for the layman to discern when a change is necessary. This object is achieved m accordance with the teachings of the invention in that the device of the kind defined in the introduction is given the characteristic features defined in the appended claim 1. Preferred embodiments of the device will appear from the dependent claims .

The invention is based among other things on the idea that the filter be visible from inside the room without the exhaust-air device having to be dismantled. This solution offers many advantages, some of which will be set forth m the following. Precisely the fact that the filter is visible makes it easy to discern when it is time to change a filter. Occupants of a room equipped with a filter of this kind want it to be clean and pleasant. Because the filter shows when it is dirty, there is no risk that the filter will be in use over too long a period. Another considerable advantage of mounting the filter so that it faces the room is that it can be attached to the exhaust-air means with the aid of a very simple device, a feature which means that the person intending to change the filter need not dismantle the exhaus -air device. As a result, anyone is able to change the filter.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described m more detail m the following by means of some embodiments thereof and with reference to the accompanying drawings, wherein

Fig 1 is an exploded view of one embodiment of a filter and an exhaust-air valve.

Fig 2 is a cross-sectional view of a filter and an exhaust-air valve.

Fig 3 is a perspective view of one embodiment of a combination filter, and

Fig 4 is a cross-sectional view of a ventilation fitting including a filter.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The filter 1 shown m Figs 1 and 2 has an edge the circumference of which corresponds to the circumference of the exhaust-air valve 2. Along the edge of the exhaust-air device is secured the hook- supporting part 3 of a Velcro fastener. The filter material forms the other part of the Velcro fastener.

The filter 1 is bowl -shaped m such a manner that when mounted on an exhaust-air device 2 the walls of the filter project outwards away from the device and approximately midway they form a bend extending towards the centre of the filter 1 back towards the device 2. In the filter designed m this way, the middle part of the filter 1 serves as a support m abutment against the disc 4 of the exhaust-air device 2. Should a thin filter material have been used m conjunction with a considerable air flow, a filter of conventional bowl shape would have collapsed. Because the filter has a stable arch-like configuration a larger area is created for through-flow of the air. A larger area means that the pressure drop becomes lower, which m turn results m lower energy consumption.

The filter 1 preferably is manufactured m a light colour, thus making it easier to discern whether the filter 1 is dirty or not. In some cases it may, however be more suitable to give the filter a dark colour to agree with that of existing dust or dirt that may be of varying appearance .

Another embodiment the visible filter 6 is shown m Figs 3 and 4. Laundry premises are generally equipped with drying cupboards 9 or similar appliances. Such cupboards may be connected to the exhaust-air device via a duct 5 and a ventilation fitting. Owing to the ventilation fitting 7, the drying cupboard 9 and the premises may be ventilated jointly. By applying a filter 6 around the ventilation fitting 7 it becomes possible to prevent dust and particles m the premises from being sucked into the exhaust -air duct. In this case, the filter 6 m principle is m the form of a piece of fabric wound m cylinder shape about a support.

The clothes inside the drying cupboard 9 generate large amounts of particles, textile fibres and dust. In order to prevent these substances from being sucked into the exhaust-air duct a piece of filter material 8 is simply applied across the ventilation opening m the drying cupboard. It should be appreciated that a large number of modifications of the embodiments described above are possible within the scope of protection of the invention as defined m the appended claims. As described above, e.g. the fastener could be of a different kind than a

Velcro fastener, such as a tightening band that clamps the filter into abutment against the exhaust-air device.

Since exhaust-air devices of a great many different configurations are available, obviously a corresponding number of filters of different shapes exist.

Claims

1. A device for reduction of build-up of dust and particle deposits m exhaust-air ducts, c h a r a c t e r i s e d m that it is equipped with a filter (1) , which is arranged to be mounted on the side of the exhaust-air device (2) that is turned towards the room so that the filter (1) , when m its mounted condition, is visibly accessible from the room-facing side.

2. A device as claimed m claim 1, c h a r a c t e r i s e d m that the filter (1) is m the shape of a bowl having an edge adapted for mounting the filter (1) on the corresponding exhaust-air device (2) .

3. A device as claimed m claim 2, c h a r a c t e r i s e d in that at least one portion of the filter (1) at some distance from the filter edge is essentially level with said edge, such that the filter part has a stable archlike configuration between said edge and said part.

4. A device as claimed m claim 1-3, c h a r a c t e r i s e d m that the filter (1) has a marginal portion forming one of the halves of a Velcro fastener, said marginal portion co-operating m a releasable engagement fashion with the second, hook- supporting half (3) of the Velcro fastener, the latter being attachable on an exhaust-air device (2) for which the filter (1) is intended.

5. A device as claimed m claim 1, c h a r a c t e r i s e d m that the filter is arranged to be mounted on a ventilation fitting (6) .

6. A device as claimed m any one of the preceding claims, c h a r a c t e r i s e d m that the filter has a light colour.

7. A method of reducing build-up of dust and particle deposits m exhaust-air ducts, c h a r a c t e r i s e d m that a filter (1) is mounted on the side of the exhaust- air device (2) that is turned towards the premises so as to be visibly available.