FILTER DEVICE

Technical field

The present document relates to tubular filter device, for separating stone or stone-like dust/debris from a stream of air.

Background

When grinding hard floor surfaces by a dry grinding process there is a need for removing the dust and debris originating from the grinding process. This is usually achieved by some sort of vacuum cleaner device where a stream of dust/debris-laden air is passed through the device. The dust and debris must be separated from the stream of air by some kind of separator device, whereby it may be collected and removed from the grinding site. The filtered air may then be passed out into the environment at the grinding site, free from residual particles from the grinding process, which particles may otherwise cause respiratory problems of the operator of the grinding device or interfere with the result of the grinding process.

There is also a desire to have a dust/debris-removing process which is easy to work with and which is able to be run in a continuous operation.

One such separator device is disclosed in WO 2005/1 181 1 1 A1. The disclosed device collects particles by means of a filter arrangement comprising a cyclone device with a coarse filter unit and a micro-filter unit. The coarse filter unit is placed above the inlet of air and a cyclone portion, and is connected to the micro-filter on the opposite side. The micro-filter is, in turn, connected to the suction side of a fan. The filter arrangement can be emptied and cleaned by means of disrupting the operation and opening a valve at the suction/outlet side of the device, letting atmospheric air in and thereby allowing the collected dust and debris to fall down through the cyclone. The debris falls through a gravity opened trap door at the bottom of the device and may then be collected in a plastic bag or any other conventional way. The device may be then switched on again for continued operation. The filter arrangement as disclosed in WO 2005/1 181 11 A1 is arranged on top of the cyclone, thus rendering the separator bulky.

US 6,447,567 B1 discloses a filter device having a tubular filter body, and end portion of which is provided with a rigid end cap with a radial seal. GB 1 551 336 discloses a tubular filter having longitudinal pleats and rigid end seals in the form of plastic or metal flanges. There is hence a need for a filter device, which may be used to provide a more compact dust/debris separator, which still presents a large enough filter surface.

Summary It is a general object of the present disclosure to provide an improved or alternative filter device, which eliminates or alleviates at least some of the disadvantages of the prior art.

A particular object is to provide a filter device that can be fitted in a compact dust/debris separator, while still providing a sufficiently large filter surface.

The invention is defined by the appended independent claims. Embodiments are set forth in the appended dependent claims and in the following description and drawings.

According to a first aspect, there is provided a filter device forseparating stone or stone-like dust/debris from a stream of air, the filter device comprising a substantially tubular body, which is open at its ends, wherein a circumferential seal is arranged at an edge of at least one of the ends, and wherein the seal is outwardly foldable.

By this open ended tubular configuration there is provided a versatile filter device which may be used in various applications, e.g. in a separator device and which may be threaded over and surrounding an inner case at the same time as it is fitted inside a housing or tube, thereby allowing for a continuous process to be run.

By a "substantially tubular body" is meant an extended body, being open at its ends and which is hollow, having a cross section which may be substantially circular, but which may also be non-circular, i.e. substantially square, oval etc..

By this seal there is provided a filter device which may be protected from leakage of particles. The seal may be arranged at the inside of at least one of the ends.

By the seal being arranged on the inside of the filter device and being outwardly foldable there is provided a way of protecting the filter from leakage combined with a way of attaching the filter device to the system in which it is intended to be used. According to one embodiment the seal may comprise at least two portions. According to one alternative the seal may comprise at least one rubber portion and at least one fibre reinforcement portion. The fibre reinforcement portion of the seal may be attached to the end of the body of the filter device. By the seal having two portions there may be provided a tight and flexible seal, which may be folded around the edge of the filter device body.

The substantially tubular body of filter material may be substantially hollow.

By having a hollow configuration of the filter there is provided a filter device which may be placed inside a tube or casing and substantially surround an inner tube or casing.

The substantially tubular body of filter material may present at least one crease extending along a length of the tubular body.

By having a body of creased filter material, there is provided a way of obtaining a larger surface area of the filter.

The substantially tubular body of filter material may have a barrel shaped configuration, wherein the waist portion is larger than the end portion.

By this configuration of the filter there is provided a way of obtaining a folded configuration and hence a larger surface area of the filter device. The substantially tubular body of filter material may further have a straight tubular configuration.

According to a second aspect of the present disclosure there is provided a method for separating stone or stone-like dust/debris from a stream of air, the method comprising using a filter device, comprising a substantially tubular body, which is open at its ends, and having a circumferential seal arranged at an edge of at least one of the ends. The method further comprises arranging the tubular body inside a substantially tubular housing of a separator device

and folding said at least one end portion of the tubular body over a circumferential edge of the tubular housing.

By arranging the filter device inside the housing of the separator device there is provided a way of enabling a continuous operation of the separator device.

According to one alternative at least one end portion of the tubular body may be arranged to seal against a wall of the tubular housing. At least one end portion of the tubular body may be clamped to the tubular housing.

By sealing and clamping the filter body against the housing wall and around the edge of the housing wall there is provided a way of eliminating leakage of particles into the filter and to the outside of the filter.

The at least one end portion may further be clamped between an edge portion of the tubular housing and a second housing portion.

According to one embodiment, the stream of air may be introduced at the inside of the tubular body, and filtered air may be drawn at the outside of the tubular body.

By introducing dust/debris-laden air at the inside of the filter and drawing filtered air from the outside of the filter, there is provided a way of continuously separating particles from the air, without the necessity for stopping the air flow for removal of dust and debris, since these particles may fall, by the action gravitational forces, to the bottom of the separator device and be collected in a traditional manner.

Brief Description of the Drawings Embodiments of the present solution will now be described, by way of example, with reference to the accompanying schematic drawings. Fig. 1 is a schematic perspective view of a filter device. Figs 2a-2c are schematic sectional view of alternative embodiments of the present solution. Figs 3a-3c are schematic side views of alternative embodiments of the present solution.

Fig. 4 is a schematic side view of a filter device and a seal. Fig. 5 is a schematic sectional side view of a separator device. Fig. 6 is a schematic sectional side view of a detail of a separator device.

Description of Embodiments

Fig. 1 illustrates a filter device 1 according to the present disclosure. The filter device 1 has a body of a filter material, which is substantially tubular, and the filter body 8 is open at both ends 2. The ends 2 may be opposing each other.

In one embodiment, the body 8 of the filter device may be substantially hollow. The body 8 may have a substantially circular cross section or a non- cylindrical cross section, such as a substantially square or oval cross section (not shown).

In one embodiment, a seal 3 may be arranged around the edge of one of the ends 2 of the filter body 8. The seal 3 may be arranged around the edge of both ends 2 of the filter body 8. The seal 3 may be arranged such that it substantially extends around the entire circumference of the filter body 8. The seal 3 may be arranged on the inside of the end portion 2 of the filter body 8 (Fig. 4).

The lower end of the filter body 8 may, according to one embodiment, be provided with a circumferential flange (not shown). The flange may present a substantially L-shaped profile, which may extend substantially radially from the filter. The flange may be made from a sheet metal material.

Figs 2a-2c and 3a-3c show alternative embodiments of the filter device 1.

In one embodiment (Figs 2a and 3a) the filter material body 8 may be folded in a controlled manner. The controlled folding may be achieved by rods around which the filter material is wrapped in an zigzag pattern, thereby creating a folded structure.

The controlled folding may also be achieved by using a filter material, which may be permanently folded. Such permanent folding may be achieved by sewing the filter material at its ends 2 to form creases extending along the length of the body 8.

In an alternative embodiment (Figs 2b and 3b), the filter material may be provided in excess, which in an expanded form forms a barrel shaped configuration of the filter body 8, where the waist portion 6 is larger than the end portions 2. In a collapsed state the filter body 8 takes on a randomly folded configuration (not shown).

In yet an alternative embodiment (Figs 2c and 3c), the tubular filter body 8 may be substantially straight.

The filter body 8 may, according to one not shown alternative, be provided with a metal netting. The metal netting may substantially enclose the outer surface of the filter body 8, for reinforcement of the filter during transport. According to one embodiment, the seal may have two portions 4, 5

(Fig. 4). According to one embodiment one portion 4 is formed by a rubber material and the other portion 5 is formed by a fibre reinforcement.

The fibre reinforcement portion 5 may according to one embodiment by fixed against the inside of the filter material. The seal 3 may, according to one embodiment, be formed from one material, for instance rubber or a rubber-like material, which may be directly fixed against the inside of the filter material.

According to one embodiment the seal 3 is folded outwardly (not shown) over the end portion 2 of the filter material such that the fibre reinforcement portion 5 entirely faces the end portion 2 of the filter body 8 and the rubber portion 4 faces the opposite direction.

The filter material may be any suitable filter material, including, as a non-limited example, woven or non-woven polypropylene fibre material.

Fig. 5 shows a separator device 10, in which a filter device 1 according to the present disclosure may be used. According to one embodiment the separator device 10 has a tubular housing 1 1 and the filter device 1 may be arranged inside the housing 1 1. The filter device 1 may further be arranged to surround an inner casing 20 of the separator device 10.

Fig. 6 illustrates that the seal 3 arranged at at least one of the end portions 2 may be arranged to engage the wall 13 of the tubular housing 1 1 and that the circumferential seal may be folded over the circumferential edge 14 of the housing. According to one embodiment is the seal 3 is clamped to the edge 14 of the tubular housing 1 1. According to one alternative the seal 3 may be clamped between the edge 14 of the housing 1 1 and a second housing (not shown). Such further housing portion may be a lid for the separator, or an outlet portion of the separator device. 18.

A stream of dust and debris-laden air may, according to one (not illustrated) embodiment, be introduced at the inside of the tubular body 8, and filtered air may be drawn at the outside of the tubular body 8. The dust and debris may hence be separated from the air at the inside of the filter device 1 and collected at the bottom of the separator device 10.