WO2001024907A1

WO2001024907A1 - A device for the separation of particles from air and an air-cleaning assembly having such a device

Info

Publication number: WO2001024907A1
Application number: PCT/SE2000/001853
Authority: WO
Inventors: Peter Krantz
Original assignee: Freshman Flimmer Ab
Priority date: 1999-10-01
Filing date: 2000-09-26
Publication date: 2001-04-12
Also published as: SE9903542L; SE515051C2; SE9903542D0; AU7820000A

Abstract

A device for separating particles from air comprises a pipe (12) which - at least in the operative state of the device - is closed at one end, while the other end of the pipe is open, more precisely via a hole serving as an outlet having a smaller diameter than the pipe. In the area of the closed end thereof, the pipe (12) has at least one wall lug (14) projecting obliquely outwards from the outside of the pipe, which lug defines an inlet opening (13). At the opposite end of the pipe, there is a wall lug (17) obliquely extending inwards from the pipe, which lug defines an opening (20) for evacuation of arriving particles which have been thrown out by the centrifugal force towards the inner side of the pipe.

Description

A DEVICE FOR THE SEPARATION OF PARTICLES FROM AIR AND AN AIR- CLEANING ASSEMBLY HAVING SUCH A DEVICE

Technical Field of the Invention In a first aspect, this invention relates to a device intended for the separation of particles from air, which comprises a casing having an inlet and an outlet between which a space extends, through which air may be sucked in a rotary, substantially helicoidal track of motion from the inlet towards the outlet for throwing out accompanying particles by centrifugal force action towards the inner side of the casing, and which communicates with a shaft -like space in which the particles may fall down and be accumulated.

Prior Art

Air-cleaning assemblies of different types generally include one filter or more accommodated a house through which polluted air is brought to pass, commonly by means of a suction fan. In order not to have coarser particles, solid or in a liq- uid state, which are included in the arriving, polluted air stopping up the filter and reducing the service life thereof in an unacceptable way, coarse-separating, particle catching devices placed up-stream the filter are used in many applications. Previously known devices for this purpose consist of cyclone separators of the type that comprises a vertical cylinder, in the upper part of which polluted air is taken in tan- gentially and is brought to move in a helicoidal, peripherical track of motion by being sucked out via a central, upper outlet pipe. The heavier particles that accompany the air will, in this connection, fall down into a shaft-like space in the form of a cone-shaped bottom part in the extension of the cylinder and be collected in a suitable way, e.g. in a bag connected to the cone-shaped bottom part.

Although cyclone separators work well in respect of the capacity of separating particles from the air, the same are associated with a number of inconveniences. Thus, the same are, regardless size, comparatively complicated and expensive to manufacture. Another nuisance is that cyclone separators require a vertical position to work, in addition to which the same are comparatively space -demanding.

Objects and Features of the Invention The present invention aims at obviating the above- mentioned inconveniences of the cyclone separators and at providing an improved particle-separating device. Thus, a primary object of the invention is to provide a separating device which is structurally simple and which may be manufactured at low cost. Another object is to create a separating device, which is compact and may be mounted in a flexible way in various air- cleaning assemblies independent of the spatial position.

In a first aspect of the invention, the above-mentioned objects are reached by means of a device of the type that is defined in the characterizing clause of claim 1.

Preferred embodiments of the device according to the invention are furthermore defined in the dependent claims 2-6.

In a second aspect, the invention also relates to an assembly intended for the cleaning of air. Features of this air-cleaning assembly are seen in claim 7.

Brief Description of the Appended Drawings

In the drawings : Fig 1 is a perspective view of an air-cleaning assembly made according to the second aspect of the invention in which a plurality of particle-separating devices according to the first aspect of the invention are included, Fig 2 is a partly transparent side view of the assembly according to fig 1,

Fig 3 is a partial end view of the assembly according to fig

2, Fig 4 is an enlarged, partially cut detailed side view illustrating the nature of the particle-separating device according to the invention,

Fig 5 is a side view corresponding to fig 4 showing a number of pipes included in the separating device, which pipes are drawn out from a house of the air-cleaning assembly, Fig 6 is a perspective view showing a first embodiment of an individual pipe included in the separating device, Fig 7 is an enlarged cross-section through the pipe according to fig 6, and Fig 8 is a perspective view showing an alternative embodiment of a particle-separating pipe.

Detailed Description of Preferred Embodiments of the Invention In fig 1 and 2 an air-cleaning assembly is visualised which in the example is of a mobile nature, but which also could be of a stationary type. The assembly includes a house generally designated 1, which per se may be built up by a plurality of different, composite sections. In the interior of the house (the space which in fig 2 is generally designated 2), at least one filter 3 for fine-filtering of incoming, polluted air is arranged. In the upper part of the house, there is a plurality of openings 4 via which polluted air may be supplied to the interior of the house from the outside. The air supply is carried out by suction by means of a fan 5 placed under the filter 3, which fan communicates with an evacuation opening 6 arranged in the bottom part of the house. This opening 6 mouths in one of the two opposite side walls 7, which advantageously may be somewhat wider than a pair of second, opposite side walls 8. Adjacent to the two opposite side walls 8, two de- vices 9 are arranged, which have the general task to separate larger or heavier particles from the arriving, polluting air before the air reaches the filter 3. Beneath these particle- separating devices 9, there are output conduits 10 with downwardly open ends to which bags 11 may be attached for collec- ting solid or liquid particles, which have been separated by the devices 9.

As far as the shown air-cleaning assembly has been described hitherto, the same is in all essentials of a conven^¬ tional nature. Reference is now made to figs 3-8, which in detail illustrate the nature of the particle-separating device according to the invention. In each device 9, a plurality of casings (more precisely five) in the form of pipes 12 are included, each pipe including one or more inlets at one end thereof. In the example according to fig 6, the pipe 12 is formed with two inlets designated 13, which advantageously are placed diametrically opposite each other. At the opposite end of the pipe, there is also an outlet for air having passed through the pipe. In the embodiment exemplified, this outlet consists of one and the same hole 4 serving as an inlet or supply opening for the air into the interior of the assembly house 1. The pipe 12 should have a rotationally symmetrical basic shape. In the example, a preferred embodiment is shown according to which the pipe is cylindrical. However, it is also feasible to form the pipe entirely or partly cone-shaped. As may be seen in fig 6, each individual inlet opening 13 is delimited by a pipe wall lug 14, which in the example is brought about by the simple measures of cutting (e.g. by means of laser radiation) two slits (marked at the edge surfaces 15 and 16, respectively) in the pipe perpendicularly to each other and then bend the defined pipe wall portion a distance outwards in relation to the rest of the pipe. In practice, the bending-out of the individual pipe wall portion should be carried out in such a way that the wall portion at least partially preserves a curved shape, although also a plane shape is conceivable. However, it is essential that the bending-out does not give rise to an abrupt upsetting line in the transition between the actual lug portion 14 and the rest of the pipe wall. When air is sucked axially through the pipe 12 - something which ultimately is carried out by means of the fan 5 - the polluted air is sucked from the outside and inwards through the openings 13 in the directions of the arrows A according to fig 7. By the fact that the two outwardly projecting wall lugs 14 form jaw-like openings, the sucked-in air will be set in a rotary motion that entails that the particles included in the air are exerted to the action of the centrifugal force.

At the inner end or downstream end of the pipe 12, there is an additional bent wall lug 17, which like the wall lugs 14 has been defined by means of two cuts 18, 19 made at an angle to each other. However, in this case the wall lug defined by the slits 18, 19 has been bent in the direction inwards in relation to the pipe wall. In this way, an opening 20 mouthing inwards is formed in the pipe through which the particles may pass .

As may be best seen in figs 4 and 5, each one of the separation pipes 12 co-operates with three spaced-apart , verti- cal plates designated 21, 8 and 22, respectively. The first- mentioned plate 21 consists of an inner, stationary partition wall in the interior of the house 1. In this wall plate, the holes 4 are recessed. As may be clearly seen in fig 4, the holes 4 (which most preferably are circular) have a diameter that is considerably smaller than the diameter of the separation pipe 12. In this connection, it should be mentioned that a short pipe piece 23 advantageously - though not necessarily - may be attached in the vicinity of the hole 4. The second vertical plate 8 consists of the outer wall of the house 1. It is axiomatic that also this wall is stationary arranged, because the same is included as an integrated part of the assembly house. The third vertical plate 22, which may consist of a simple sheet-metal plate, is, however, movable inasmuch as the same may be dismounted from the assembly house. Advantageously, all pipes 12 in the individual separating device 9 are jointly attached to the inside of this plate 22, the plate closing the outer end openings of the pipes. Thus, the plate 22 has a larger extension than the individual pipes, a vertical gap 24 being delimited between the two plates 8, 22 through which the air passes when it is sucked into the different inlet openings 13 of the pipes. Furthermore, as seen in fig 4, the axial length of the inlet openings 13 corresponds to the distance between the plates 8, 22. In practice, the plate 22, and thereby all appurtenant pipes 12, are lockable in relation to the assembly house with suitable means, e.g. two screws 25. In order to facilitate the mounting and dismounting of the plate 22, there may be a handle 26 on the outside thereof.

In the outer wall 8 of the assembly house, there are holes 27 having the same rotationally symmetrical cross-section shape and diameter as the pipes 12. In other words, the pipes may be stuck in through the holes 27 in order to be sealingly pressed against the outside of the partition wall 21 in an operative state. The Function and Advantages of the Inven ion

When particle-containing is to be cleaned in the described assembly, the fan 5 is started, which brings about a negative pressure in the interior of the assembly house, and thereby a suction effect inside the separation pipes 12. The air being in the room outside the assembly will, therefore, be sucked into the gap 24 and through each one of the jaw- like inlet openings 13. In the outer portion of each pipe 12, the sucked-in air is set in a rotary motion which ensures that the accompanying particles are exerted to the action of the centrifugal force, whereby the particles are thrown out towards the inner side of the pipe. When the air enters into the inner end of the pipe, the same will be sucked out at a comparatively high speed in the central area defined by the diameter of the hole 4. By the existence of the ring-shaped portion of the wall or plate 21 extending between the pipe 12 and the smaller hole 4, and which in fig 4 is designated 28, the air flow will slow down in the peripheral area of the pipe. This is something which means that the flow speed in the area up-stream the ring portion 28 and inside the inner side of the pipe 12 is reduced to a minimum (in the immediate vicinity of the ring portion 28, the flow speed approaches zero). Nevertheless, the helicoidally rotating particles continue the track of motion thereof along the inner side of the pipe to finally reach the jaw-like outlet opening 20. When this takes place, the particles are thrown out through the opening 20 so as to fall down into the shaft-like space 29 which is delimited between the wall plates 8, 21. Via this shaft space, the particles fall down into the outlet con- duit 10 to finally be collected in the bag 11.

When the incoming air has passed the individual separating pipe 12, the same has been liberated from coarser particles. Thus, there are only smaller (e.g. invisible) particles left in the air, which may be removed from the air flow when this passes the filter 3. In this way, the filter obtains a long service life.

A substantial advantage of the particle-separating device according to the invention is that the same may be manufactured in a simple and cost-saving way. Thus, the individual separating pipe may be produced by the simple measures of cutting slits in a common pipe, e.g. a sheet -metal pipe, and then bend the wall portions defined by the slits outwards and inwards, respectively, in relation to the pipe. Furthermore, in comparison with previously known cyclone separators, the separating device according to the invention is compact as well as flexibly practicable so far that the separation pipes not necessarily require a vertical position. On the contrary, the pipes may advantageously be oriented horizontally, as has been exemplified in the drawings.

In fig 8 an alternative embodiment of a separating pipe is illustrated which is even simpler to manufacture than the pipe according to fig 6. In this case, the individual bent wall lugs 14 and 17, respectively, are defined by only one sin- gle slit (outlined at the edge surfaces 30, 31) . Of these slits, the slits 30 which define inlet openings 13 may be axi- ally oriented, the wall lug 14 being bent in relation to an oblique transition portion, while the slit 31 extends obliquely in relation to the axial direction of the pipe. In doing so, the wall lug 17 is provided by bending in the wall material relatively an axially extending transition portion.

In order to facilitate the evacuation of particles through the outlet openings 20 and the transfer thereof to the shaft-like space 29, it is feasible to provide a certain nega- tive pressure in this space. This may be realized by the simple measure of forming a hole (not shown) in the wall sheet 21, e.g. in the area of the upper edge thereof, thereby providing in the main the same low air-pressure in the space 29 as in the interior of the house space 2.

Feasible Modifications of the Invention

Although the particle-separating device according to the invention has been shown and described in connection with the special and preferred, per se. air-cleaning assembly that has been shown in figs 1 and 2, the general idea according to the invention is also applicable in many other applications where it is desirable to delete coarse particles from air. Thus, the separating device according to the invention may, per se , work independently, i.e. without the co-operation of one or more fine-cleaning filters. Furthermore, it should be pointed out that the invention in the preceding description as well as subsequent claims has been accounted for in connection with cleaning of air. However, to those skilled in the art, it is evident that the separating device according to the invention also may be used to clean other arbitrary gases of particles. As has been indicated above, the particles in question may consist of not only solid constituent parts, but also liquid constituent parts, such as oil or paint drops.

Claims

1. Device for the separation of particles from air, including a casing (12) having an inlet (13) and an outlet (14) between which a space extends, through which air may be sucked in a rotary, substantially helicoidal track of motion from the inlet towards the outlet for throwing out the accompanying particles by centrifugal force action towards the inner side of the casing, and which communicates with a shaft-like space (29) in which particles may fall down and be accumulated, c h a r- a c t e r i z e d in that the casing consists of a pipe (12) having a rotationally symmetrical basic shape, which - at least in the operative state of the device - is closed at one end thereof, while the other end of the pipe is open, more pre- cisely via a hole (4) serving as an outlet, which hole is recessed in an end wall (21) and has a cross-section area which is smaller than the cross-section area of the pipe, that the pipe in the area of the closed end thereof has at least one wall lug (14) projecting obliquely outwards from the outside of the pipe, which lug defines an opening (13) serving as an inlet, and that the pipe in the area of the opposite end thereof has a wall lug (17) extending obliquely inwards from the pipe, which lug defines an opening (20) for the evacuation of arriving particles to said shaft space (29) .

2. Device according to claim 1, c h a r a c t e r i z e d in that the shaft space (29) is delimited between two spaced-apart wall plates (21,8) of which a first one forms said end wall (21) and the second one (8) co-operates with a third, pipe- closing plate (22) , which has a larger extension than the diameter of the pipe in order to define a gap (24) together with the second plate through which gap air from the outside is sucked into the inlet opening (13) of the pipe.

3. Device according to claim 2, c h a r a c t e r i z e d in that the pipe lug (14) defining the inlet opening (13) is formed of at least one slit (15,16; 30,31) which extends all the way between said second and third wall plates (8,22) .

4. Device according to claim 3, c h a r a c t e r i z e d in that said lug (14) is formed of not only one main slit extending axially, but also a transverse second slit (16) .

5. Device according to claim 3, c h a r a c t e r i z e d in that the slit (31) is oblique in relation to the longitudinal axis of the pipe (12) .

6. Device according to any one of claims 2-5, c h a r a c- t e r i z e d in that the same comprises a plurality of pipes (12) , which are detachably mounted in holes (27) in the second plate (8) and connected with a corresponding number of outlet holes (4) in the first plate (21), all pipes being jointly fixed to the third plate (22) , which is lockable relatively the second plate (8) .

7. Assembly for the cleaning of air, comprising a house (1), which includes one or more first openings (4) for supplying polluted air from the outside to the interior of the house, as well as at least one second opening (6) for evacuating cleaned air from the interior of the house, and inside which there is at least one filter (3) for fine filtering of passing air, as well as a fan (5) for transporting air from the inlet opening (4) towards the evacuation opening, a coarse-separating device being arranged adjacent to the individual inlet opening (4) which device has the purpose of separating coarser particles from the polluted air before this reaches said filter, c h a r- a c t e r i z e d in that a device (9) according to any one of the preceding claims is mounted as a coarse-separating device.