EP3552711B1 - Electrostatic filter unit and ventilation device with electrostatic filter unit - Google Patents

Description

The present invention relates to an electrostatic filter unit and a ventilation device with such a filter unit

In the case of ventilation devices, it is known to filter out impurities from the air. Mechanical filters can be used here, such as fleece mats, porous foam media, expanded metal filters or perforated metal filters. In the case of ventilation devices, which represent extractor hoods that are operated in a kitchen, liquid and solid impurities are filtered out of the vapors and vapors produced during cooking. In particular, expanded metal filters, perforated sheet metal filters, baffle filters, which can also be referred to as eddy current filters, edge suction filters and porous foam media are used as mechanical filters.

In the JP 2000 000 488 A an electrical precipitating filter comprising first and second dust collection electrodes is described. The first dust-collecting electrodes are composed of an electric conductor covered with an electric insulation film and extend in a meandering manner. The second dust-collecting electrodes have spacers that support the first dust-collecting electrodes. The left and right ends of the second dust-collecting electrodes are alternately attached to a side wall.

the US 3,778,970A discloses an electric air cleaner in which parallel collector plates are slidably and detachably housed in a frame member. An ionizing wire is drawn in a zigzag configuration to overlie each of the collector plates. The collector plates are connected in a form-fitting manner by means of electrical contact means which supply all collector plates with the same potential. The frame member includes two vertical struts made of an electrically insulating material. When the collection plates are slid into horizontally extending gaps in the struts, they are secured to the rear of the struts via generally U-shaped channel strips. the Channel strips are made of an electrically non-conductive material, in particular plastic, while other channel strips are made of electrically conductive material.

In the US 3,729,815 A describes a method of installing a plurality of dust collecting plates. The plurality of dust collection plates are attached to each other to form a bundle of such plates. The bundle is inserted into a sleeve of an electrostatic precipitator. Supports are provided in the sheath to support the bundle. For this purpose, indentations are made in the support elements.

In the US 4,747,856A describes an apparatus for aligning the lower ends of electrostatic precipitator electrodes. The device includes an elongated rod aligned with the lower ends of the electrodes. The rod has a plurality of opposed gate-shaped alignment elements.

In addition, for example, from the DE 2146288 A a fume hood using an electrostatic filter is known. The electrostatic filter in this extractor hood consists of plate-shaped separation and counter electrodes as well as wire-shaped ionization electrodes. The plate-shaped deposition electrodes are connected to one another via electrically conductive webs, and the counter-electrodes are also connected to one another via electrically conductive webs. The separation and counter-electrodes are arranged in such a way that the air entering the filter first flows against the separation electrodes with wire-like ionization elements lying between them and then reaches the counter-electrodes offset upwards. The separating electrodes and counter-electrodes are fastened to the housing of the extractor hood via partitions which run perpendicularly to the electrodes and parallel to one another. The separating electrodes and counter-electrodes alternately engage in one another in the manner of a comb. In addition, a high-voltage device is provided in the housing of the extractor hood, which is connected to the electrodes of the filter.

A disadvantage of this electrostatic filter is the large number of parts and the complex structure of the filter. In addition, the correct arrangement and insulation of the electrodes from one another is complex.

The present invention is therefore based on the object of providing a solution in which a simple design and simple assembly of an electrostatic filter unit is possible and the electrostatic filter unit can nevertheless be operated reliably.

The invention is based on the finding that this object can be achieved by using a holding device which is used to hold the separating electrode(s) of a separating unit of the electrostatic filter unit and which at the same time acts as a counter-electrode.

According to a first aspect, the object is achieved by an electrostatic filter unit for a ventilation device. The filter unit comprises an ionization unit and a separating unit with at least one separating electrode, wherein the separating unit has a holding device for holding the at least one separating electrode, the holding device has a guide geometry for the at least one separating electrode and the holding device consists of electrically conductive material. The filter unit is characterized in that the holding device comprises a first and a second boundary wall and at least two frame webs located between the first and second boundary wall, in that a receiving space for at least part of a separation electrode is formed between two adjacent frame webs and in that the guide geometry has at least one Includes through slot for a deposition electrode through one of the boundary walls.

A ventilation device is a device that can be used to suck air out of a room and clean it. The ventilation device can represent an extractor device, for example in a kitchen. However, the ventilation device can also represent a wall box or a ceiling ventilation, for example. The air flow can be caused by a fan of the ventilation device.

The electrostatic filter unit serves to filter out impurities from the air that is transported through the ventilation device. The electrostatic According to the invention, the filter unit has an ionization unit and a separation unit. The separating unit is downstream of the ionization unit in the direction of flow. The separation unit can also be referred to as a separation area or separation stage and the ionization unit as an ionization area or ionization stage.

The ionization unit preferably has at least one ionization element and at least one counter-electrode. Voltage, preferably high voltage, is applied to the ionization element. When contaminated air flows through the ionization unit, solid and liquid substances are electrostatically charged by means of the ionization element, which can also be referred to as a discharge electrode.

The separating unit comprises at least one separating electrode. In addition, the separating unit comprises at least one counter-electrode. According to the invention, the counter-electrode is formed by the holding device. Due to the electric field generated by the separating electrode and counter-electrode, the impurities charged in the ionization unit settle on the surface of the separating electrodes and counter-electrodes of the separating unit, which can be collectively referred to as collecting electrodes, and are thus filtered out of the air.

The filter unit is also referred to as a filter module. The filter unit is preferably a portable filter unit that can be removed from the ventilation device and is preferably preassembled. A filter unit is referred to as preassembled, which can be inserted into the ventilation device as a structural unit and can be removed from it in one unit. The separating unit and the ionization unit can, for example, be accommodated in a common housing.

The front side of the filter unit is the side through which the air enters the ionization unit. The rear side is the side on which the separating unit is formed and through which the air exits from the filter unit. The filter unit is thus flowed through in the direction of flow from the front to the rear.

In the electrostatic filter unit according to the invention, which is also referred to below as a filter unit, the separating unit has a holding device for holding the at least one separating electrode on the holding device. The holding device can also be referred to as a holding frame or frame. The holding device has a guide geometry for the at least one deposition electrode. A geometry on the holding device that guides the deposition electrode when it is inserted into the holding device and holds it in the inserted state is referred to as a guiding geometry. The guiding geometry can consist of one or more slots, grooves and/or edges.

According to the invention, the holding device consists of an electrically conductive material. In particular, a solid material is referred to as an electrically conductive material which has an electrical conductivity which is preferably >10 ⁶ S/m at 25° C. In particular, metals or conductive plastic can be used as the electrically conductive material. In this context, conductive plastic is plastic that represents an intrinsically conductive polymer or is a polymer provided with conductive fillers. Aluminum, for example, can be used as the metal for the holding device.

The holding device with the separating electrode or electrodes is preferably accommodated in a housing made of non-conductive material. This housing has an inlet opening and an outlet opening, with the ionization unit being located behind the inlet opening in the direction of flow and the outlet opening being located behind the separating unit in the direction of flow. In addition, in the filter unit according to the invention, as will be explained in more detail later, at least the separating electrode(s) and/or the holding device is at least partially insulated. In particular, the separating electrode(s) and/or the holding device are insulated at least in the contact areas in which they are in contact with one another.

Because the holding device consists of an electrically conductive material, it can function as a counter-electrode for the separating unit. In particular, the holding device can be connected to the ground of a high-voltage unit and thus form the counter-electrode for the at least one separating electrode of the separating unit. The holding device thus fulfills two requirements in the filter unit according to the invention functions. On the one hand, the deposition electrode(s) are accommodated or held and aligned by this and, on the other hand, the holding device serves as a counter-electrode. A number of advantages can be achieved in this way. In particular, the structure of the filter unit is simplified, since only the separating electrode(s) must be attached to the holding device or introduced into it. Since a guide geometry is also provided on the holding device, the assembly of the filter unit is also simplified. In addition, separate guide elements are not absolutely necessary, so that this also reduces the number of parts. Furthermore, only one contact point is required for connecting the fixture as a counter-electrode to the earth of a high-voltage unit.

According to the invention, the holding device comprises a first and a second boundary wall and at least two frame webs located between the first and second boundary wall. The frame webs are firmly connected to the boundary walls and are preferably configured in one piece with the boundary walls. A receiving space for at least part of a deposition electrode is formed in the holding device between two adjacent frame webs. In addition, in this embodiment, the guide geometry preferably includes at least one passage slot for a deposition electrode through one of the boundary walls. The through slit or slits represent elongated slits.

The holder preferably has a rectangular box shape open to the front and rear. In this context, the side of the holding device that faces the ionization unit is referred to as the front side. The back is the side of the holding device that faces away from the ionization unit. The first and second boundary walls are preferably parallel to one another. The first boundary wall can, for example, be the upper side of the holding device and the second boundary wall can be the underside of the holding device. However, it is also within the scope of the invention that one side wall of the holding device forms the first boundary wall and the opposite side wall forms the second boundary wall. However, the first and second boundary walls are always opposite one another on the holding device. The holding device comprises at least two frame webs. These frame webs are between the first and the second boundary wall. The frame webs are oriented to extend between the front and back of the fixture. The frame webs are particularly preferably perpendicular to the front or rear of the holding device. Since air flows through the holding device in this direction, the blockage is small when the frame webs are aligned in this direction. The frame webs can be arranged at the ends of the first and second boundary wall. However, at least one frame web is preferably also arranged between the lateral ends of the first and second boundary walls. The holding device particularly preferably has a large number of frame webs. Depending on the size of the holding device, for example, more than ten or even more than twenty frame webs can be provided.

A receiving space for at least part of a deposition electrode is preferably formed in each case between two adjacent frame webs. As a result, the separating electrodes and the frame webs of the holding device are present in alternation in the separating unit.

According to the invention, the guide geometry includes at least one passage slot for a deposition electrode through one of the boundary walls. The through slot can also be referred to as a through slot. The provision of at least one through slot makes it possible to bring the at least one deposition electrode into the area between the boundary walls and in particular into a receiving space. The through slot is dimensioned in such a way that its area corresponds to the cross section of the deposition electrode. As a result, the deposition electrode is guided through the through-slot on the one hand when it is introduced. On the other hand, the deposition electrode is also held in position by the through-slot after it has been inserted.

Preferably, a plurality of through slits are provided in a boundary wall and the through slits are parallel to each other.

According to a preferred embodiment, the frame webs extend perpendicular to the first and second boundary wall of the holding device and are parallel to one another. The at least one through-slot is particularly preferred Guide geometry each introduced between two frame webs in one of the boundary walls. The through-slot is particularly preferably introduced in the middle between two frame webs. The through-slot lies parallel to the cross-section of the frame webs. The central arrangement achieves a centering of the deposition electrode introduced through the through-slot between the frame webs. In particular, flexible deposition electrodes can also be used, which are then aligned as centrally as possible between the fixed frame webs. Since the frame webs, as part of the holding device, act as a counter-electrode, this ensures that the electric field is reliably built up and a breakdown or short circuit can be prevented due to the uniform spacing.

According to a preferred embodiment, at least one through-slot is introduced in the first boundary wall and likewise at least one through-slot is introduced in the second boundary wall, which is aligned with the at least one through-slot in the first boundary wall. In this embodiment too, a plurality of through-slots are preferably made in the first boundary wall and the number of through-slots in the first boundary wall corresponds to the number of through-slots in the second boundary wall. The passage slits in the boundary walls lie exactly one above the other within the scope of the processing tolerances. Since the holding device is preferably a form-fitting web-frame construction consisting of the boundary walls and the frame webs, a force required for prestressing a flexible deposition electrode that is to be inserted into the holding device can be safely absorbed by the holding device, so that deformation of the frame is avoided by the preload.

Since the through-slots are also aligned with one another, the deposition electrode can be inserted into the receiving space through the through-slot in the first boundary wall and taken out of the receiving space again through the through-slot in the second boundary wall, or vice versa. In this embodiment, the deposition electrode therefore preferably has a length that is greater than the distance between the first and the second boundary wall. As a result, in addition to being in contact with the through-slots, the deposition electrode can also be fixed at a point outside the receiving space, for example the top side of the first boundary wall or the bottom side of the second boundary wall. The mounting of the deposition electrode is thus further improved.

According to a preferred embodiment, the edges of the at least one through-slot are rounded. By rounding off the edges, the deposition electrode can be deflected by a radius of curvature that corresponds to the rounding and can lie against the rounded edge. Damage to the deposition electrode or a coating of the deposition electrode can be prevented in this way.

According to a preferred embodiment, the deposition electrode is formed by a band that extends through at least two receiving spaces of the holding device perpendicular to the first and second boundary wall. In this case, the band is preferably guided through through-slots in the boundary walls. This embodiment has the advantage that the number of contact points required for contacting the collecting electrodes with the high-voltage unit is limited to two. In particular, only the holding device as a counter-electrode has to be connected to the ground of the high-voltage unit and the strip-shaped separating electrode has to be connected to the positive connection of the high-voltage unit.

According to one embodiment, the strip-shaped deposition electrode can be threaded through the through-slots of the holding device and pulled taut. In this case, the deposition electrode is first guided through a first through-slot in the first boundary wall, and then through the first through-slot in the second boundary wall, which is aligned therewith. A part of the length of the separating electrode thus extends perpendicularly to the boundary walls and is preferably located centrally between two adjacent frame webs. The deposition electrode is then bent over and inserted into the passage slot of the second Introduced boundary wall, which is adjacent to the passage slot through which the deposition electrode was led out. The deposition electrode is then inserted from the inside into a through-slot of the first boundary wall, which is adjacent to the first through-slot. This threading is repeated until the deposition electrode passes through each of the passage slots in the boundary walls. One end of the band-shaped deposition electrode can, for example, be fixed, for example clamped, on the upper side of the first boundary wall. The other end of the strip-shaped separating electrode is then led to a contact point which can be provided in the holding device or on an outside of the holding device and via which the separating electrode can be connected to the high-voltage unit.

As an alternative to threading in a strip-shaped separating electrode, the separating electrode can be a preformed component that has a meandering shape. In this embodiment, the holding device is preferably designed in such a way that the through-slots extend as far as the front or the rear of the respective boundary wall. Thus, in this embodiment, the through-slots are open to one side. From the open side, the preformed meander-shaped deposition electrode can be introduced into the holding device, that is to say pushed in. The through-slots can then be closed, for example, by a strut or a cover frame. The length of the individual meandering arms is therefore so long in this embodiment that it corresponds to the distance between the top of the first boundary wall and the bottom of the second boundary wall. The distance between the meandering arms corresponds to the distance between adjacent through-slots in one of the boundary walls. This embodiment further minimizes the effort involved in producing the separating unit.

According to an alternative embodiment to the embodiment in which through-slots are provided in both boundary walls, at least one through-slot is introduced in the first boundary wall and at least one guide groove is introduced in the second boundary wall, which is connected to the Through slot of the first boundary wall is aligned. This embodiment has the advantage that a plate-shaped deposition electrode can be introduced through the passage slot of a boundary wall and can be guided with one edge into the guide groove of the other boundary wall and held there. In this embodiment, only through slots are preferably provided in one boundary wall and only guide grooves are provided in the other boundary wall. As a result, the deposition electrodes to be introduced into the holding device can be introduced and contacted from one side, namely the boundary wall in which the through-slots are provided.

In this embodiment, the at least one separating electrode preferably represents a flat plate and a separating electrode is at least partially accommodated in each accommodation space.

In order to prevent a short circuit between the precipitation electrode or electrodes and the holding device, insulation is preferably provided according to the invention between the precipitation electrodes, ie the precipitation electrodes and the holding device.

According to one embodiment, the at least one deposition electrode is insulated over its entire surface, except for a contact area for making contact with the high-voltage unit. In this case, the insulation can be produced by a coating with an insulating material, which is also referred to as an insulator. The contact area for making contact with the high-voltage unit is preferably left out of such a coating. However, it is also possible for the at least one deposition electrode to also be provided with insulation in the contact area for making contact with the high-voltage unit, and for the contact to be made by means that penetrate through the insulation.

Alternatively or additionally, the holding device can also be insulated. In this case, too, the insulation can be produced by a coating. In an isolated Holding device is the isolation of at least one separation electrode no longer absolutely necessary and vice versa.

According to one embodiment, the at least one deposition electrode has a contact projection as the contact area, which protrudes outwards beyond the boundary wall in which the at least one through-slot is introduced. The contact projection can be, for example, a contact lug on an edge of a plate-shaped deposition electrode. After all plate-shaped deposition electrodes have been placed in the holding device, they can be connected to the high-voltage unit via a single contact element, for example a rail, which extends along the protruding contact projections. Individual contacting of the deposition electrodes is therefore no longer necessary.

According to one embodiment, the at least one through-slot on the holding device ends at a distance from the front and rear of the holding device. The at least one deposition electrode preferably has a cross section that corresponds to the area of the through-slot. Since the through-slot is delimited to the front and to the rear by the material of the boundary wall in which it is introduced, the deposition electrode can be prevented from shifting or even falling out.

The holding device can be manufactured as an integral part, i.e. in one piece. Here, in addition to the boundary walls and the frame webs, the guide geometry is preferably also formed during the manufacture of the holding device. The holding device can be produced, for example, by injection molding. This type of production has the advantage that the contours of the holding device, in particular the boundary walls with the through slot and/or guide groove and the frame webs, can be produced in a simple manner during production. Subsequent formation of the guide geometry, for example subsequent introduction of through-slots or guide grooves, is not necessary.

As an alternative to the one-piece embodiment, the holding device can also be constructed in two parts, one part comprising the boundary walls with the introduced guide geometry and another part representing a cover frame that closes off the guide geometry to the front or to the rear. The first part preferably also has the frame webs. In this embodiment, the through-slots extend to the front or rear of the first part. As a result, a preformed deposition electrode, which in particular has a meander shape, can be pushed in via the open side of the through-slots. After the deposition electrode has been introduced, the covering frame can then be applied to the side of the first part and the through-slots can thereby be closed. The cover frame can consist of one or more parts. For example, the cover frame can consist of two struts, each of which is fastened to the side of the respective boundary wall. However, it is also possible for the cover frame to be designed in one piece, with the struts mentioned being connected to one another via connecting webs at the edge.

According to one embodiment, a plate-shaped extension is arranged on the holding device on the front side of the first and the second boundary wall, each extending into the ionization unit and forming the counter-electrodes of the ionization unit. The plate-shaped extensions preferably extend in the surface direction of the respective boundary wall. Thus, the extensions are parallel to each other. This embodiment has the advantage that the overall structure of the filter unit is further simplified. The extensions are preferably formed in one piece with the boundary wall. This is possible in a simple manner, in particular when the holding device is produced by an injection molding process. Separate contacting of the counter-electrodes of the ionization unit, in particular a connection to the ground of the high-voltage unit, is no longer necessary in this embodiment, since the holding device, as the counter-electrode of the separating unit, is already connected to ground.

According to a further embodiment, the holding device has, on a lateral edge of the boundary walls, a contact space for contacting the at least one deposition electrode, which consists of a non-conductive material.

According to a further aspect, the invention relates to a ventilation device which comprises at least one electrostatic filter unit according to the invention.

Advantages and features that are described with regard to the electrostatic filter unit also apply - as far as applicable - to the ventilation device and vice versa.

The electrostatic filter unit can be arranged on the ventilation device, preferably in the suction opening. Alternatively, the electrostatic filter unit can also be installed in the ventilation device downstream of the suction opening in the direction of flow. The electrostatic filter unit is built into the ventilation device in such a way that incoming air first flows through the ionization unit before it reaches the separation unit.

• Figur 1: eine schematische Perspektivansicht einer Ausführungsform der erfindungsgemäßen Lüftungsvorrichtung;
• Figur 2: eine schematische Perspektivansicht einer ersten Ausführungsform einer Haltevorrichtung der erfindungsgemäßen elektrostatischen Filtereinheit;
• Figur 3: eine schematische Schnittansicht der Ausführungsform der Haltevorrichtung nach Figur 2;
• Figur 4: eine schematische Perspektivansicht der Ausführungsform der Haltevorrichtung nach Figur 2 mit Abscheideelektrode;
• Figur 5: eine schematische Detailansicht eines Teils der Haltevorrichtung und der Abscheideelektrode nach Figur 4;
• Figur 6: eine schematische Perspektivansicht einer zweiten Ausführungsform einer Haltevorrichtung der erfindungsgemäßen elektrostatischen Filtereinheit mit Abscheideelektroden; und
• Figur 7: eine schematische Schnittansicht der Ausführungsform der Haltevorrichtung mit Abscheideelektroden nach Figur 6.

The invention is described again below with reference to the accompanying figures. Show it:

• figure 1 1: a schematic perspective view of an embodiment of the ventilation device according to the invention;
• figure 2 : a schematic perspective view of a first embodiment of a holding device of the electrostatic filter unit according to the invention;
• figure 3 : a schematic sectional view of the embodiment of the holding device according to FIG figure 2 ;
• figure 4 : a schematic perspective view of the embodiment of the holding device according to FIG figure 2 with separator electrode;
• figure 5 : a schematic detailed view of a part of the holding device and the deposition electrode figure 4 ;
• figure 6 : a schematic perspective view of a second embodiment of a holding device of the electrostatic filter unit according to the invention with separating electrodes; and
• figure 7 1: a schematic sectional view of the embodiment of the holding device with deposition electrodes figure 6 .

In figure 1 an embodiment of a ventilation device 5 according to the invention is shown, which represents an extractor hood in the form of a ceiling ventilation. In the illustrated embodiment, the ventilation device 5 has a ventilation housing 50 and a baffle plate 51 lying below, that is to say in the direction of flow in front of the underside of the ventilation housing 50 . A suction opening 52 is formed between the underside of the ventilation housing 50 and the baffle plate 51, which can also be referred to as a suction gap. Several filter units 1 are placed in the suction opening 52 . In the view shown, two filter units 1 are introduced across the width of the ventilation device 5 and one filter unit 1 across the depth of the ventilation device 5 . The ventilation device 5 is fitted above a hob 6 and can be accommodated, for example, in the ceiling (not shown), with at least the suction opening 52 being at least temporarily below the ceiling. Of the filter units 1 are in the figure 1 only the protective grille 10 attached to the front of the filter units 1 can be seen.

In figure 2 a perspective view of a first embodiment of the holding device 30 of the electrostatic filter unit 1 according to the invention is shown. The filter unit 1 has an ionization unit 2 and a separation unit 3 . From the ionization unit 2 are in the figure 2 only the counter electrodes 20 are shown. In addition, an ionization electrode (not shown) is also provided in the ionization unit 2, which can be a wire, for example, which extends in the width direction of the filter unit 1 parallel to the counter-electrodes 20 between them.

The ionization unit 2 is located upstream of the separating unit 3 in the direction of flow. The direction of flow is indicated schematically by the arrow S in FIG. From the separating unit 3 is in figure 2 only the fixture 30 is shown. The holding device 30 forms the counter-electrode of the filter unit 1 according to the invention Separation unit 3. In addition, the separation unit 3 has a separation electrode 31 (see figure 4 ), which will be described in more detail later.

The holding device 30 has a box shape. The side of the holding device 30 and thus of the separating unit 3 which faces the ionization unit 2 is also referred to below as the front side. The opposite side of the holding device 30 and thus of the separating unit 3 is also referred to as the rear. The holding device 30 is open to the front and to the rear. In particular, the holding device 30 consists of a first boundary wall 300 and a second boundary wall 301 which lie parallel to one another and form the top and bottom of the holding device 30 . Between the boundary walls 300, 301 run perpendicular to the boundary walls 300, 301 standing frame webs 303. The frame webs 303 extend parallel to each other from the front to the back of the holding device 30 and have a low material thickness. A receiving space 302 is formed in each case between two adjacent frame webs 303 . On the lateral edge of the boundary walls 300, 301, the holding device 30 in the illustrated embodiment has a side wall 307 which lies parallel to the frame webs 303 but has a greater material thickness than the frame webs 303.

In the embodiment shown, through-slots 304 are made in the first boundary wall 300, which is also referred to below as the upper side of the holding device 30. The through slits 304 extend in the depth direction of the boundary wall 300, that is, in the direction from the front to the rear of the holder 30. The through slits 304 are parallel to each other. As emerges from the figure 3 , which shows a sectional view, the through slots 304 are located in the width direction of the first boundary wall 300 in the middle between the frame webs 303.

How out figure 3 Furthermore, in the embodiment shown, through-slots 304 are also introduced in the second boundary wall 301, which is referred to below as the underside of the holding device 30. The through-slots 304 in the lower boundary wall 301 are aligned with the through-slots 304 in the upper Boundary wall 301 aligned, i.e. also in the middle between adjacent frame webs 303.

A cover frame 309 is provided on the back of the holding device 30 . A strut 308 is formed on the rear side of the boundary walls 300, 301 by the cover frame 309. FIG. This strut 308 closes the through-slots 304 to the rear. The cover frame 309 can be formed in one piece with the boundary walls 300, 301. In particular, the strut 308 can be formed by introducing the through slots 304 into the upper boundary wall 300 .

How out figure 3 results, the edges of the through slots 304 are rounded.

In the first embodiment of the holding device 30, this can also be referred to as a clamping frame for a deposition electrode 31, which represents a flat conductor which is insulated at least at the points of contact with the holding device 30, but preferably completely.

With reference to Figures 4 and 5 the embodiment of the deposition electrode 31, which is preferably used in the first embodiment of the holding device 30, will now be described. In the embodiment shown, the separating electrode 31 is a flat conductor, in particular a metal strip. A locking device (not shown) or a clip (not shown) can be provided there for clamping the end of the deposition electrode 31 . From this end, the separating electrode 31 is guided through a first through-slot 304 in the first boundary wall 300 and then runs perpendicularly through a first receiving space 302. The separating electrode 31 extends through a first through-slot 304 in the second boundary wall 301. The deposition electrode 31 is bent over on the underside of the second boundary wall 301 and guided through a second through-slot 304 adjacent to the first through-slot 304 into a second receiving space 302 of the holding device 30 . The deposition electrode 31 extends through this receiving space 302 parallel to the frame webs 303 and passes through the second through-slot 304 adjacent to the first through the upper side of the receiving space 302 Through slot 304 upwards. There, the deposition electrode 31 is bent over again and inserted into the third through-slot 304 of the first boundary wall 300, which is adjacent to the second through-slot 304.

This course of the separating electrode 31 continues up to the side of the holding device 30 which is opposite the side on which the first end of the separating electrode 31 is located. In the embodiment shown, a contact space 4 is arranged on this side of the holding device 30 . This can be formed by non-conductive casting compound on the holding device 30 . The second end of the deposition electrode 31 is introduced into the contact space 4 and can be connected there to a high-voltage unit (not shown).

The material of the boundary wall 300, 301 is rounded at the contact points of the deposition electrode 31 on the holding device 30, in particular on the first and second boundary wall 300, 301 between the through-slots 304. The radius of the rounding is determined in particular by the allowable bending radius of an insulating coating on the separating electrode 31 .

The deposition electrode 31 can be introduced by threading in the flat conductor in the manner described. In this case, a guide device (not shown) can preferably be introduced into the receiving spaces 302 from the front or rear, which fills them up except for a gap through which the deposition electrode 31 is to be guided.

As an alternative to threading, it is also possible that the separating unit in the Figures 4 and 5 shown shape is preformed. In this embodiment, the holding device 30 is then preferably configured in two parts. The boundary walls 300, 301 with the through slots 304 and the frame webs 303 are formed in one of the two parts. The through-slots 304 are open at one longitudinal end on the first part. The preformed deposition electrode 31 can be pushed into these open through-slots 304, for example from behind. After the deposition electrode 31 has been pushed in, the second part, which can be referred to as the cover frame 309, is then put on and closes the open ends of the through-slots 304 to the rear.

In the Figures 6 and 7 a second embodiment of the separation unit 3 of the filter unit 1 according to the invention is shown.

The second embodiment differs from that in FIGS Figures 2 to 5 shown first embodiment characterized in that the holding device 30 only in the first boundary wall 300 has through slots 304. In addition, in the figure 2 no extensions 306 of the holding device 30 are shown on the front side, which serve as counter-electrodes of the ionization unit 2. However, the provision of such extensions 306 is also possible in the second embodiment of the holding device 30 .

As in the first embodiment, the holding device 30 in the second embodiment has a box shape. The holding device 30 is open to the front and to the rear. In particular, the holding device 30 consists of a first boundary wall 300 and a second boundary wall 301 which lie parallel to one another and form the top and bottom of the holding device 30 . Between the boundary walls 300, 301 run perpendicular to the boundary walls 300, 301 standing frame webs 303. The frame webs 303 extend parallel to each other from the front to the back of the holding device 30 and have a low material thickness. A receiving space 302 is formed in each case between two adjacent frame webs 303 .

In contrast to the first embodiment, no through-slots are made in the second boundary wall 301 in the second embodiment. Instead, guide grooves 305 are introduced in the upper side, the second boundary wall 301, that is to say the side of the second boundary wall 301 which faces the first boundary wall 301. The guide grooves 305 are positioned in such a way that they are aligned with the through-slot 304 in the first boundary wall 300 , ie lie vertically below the through-slot 304 .

In the second embodiment, deposition electrodes 31 are placed in the holding device 30 and each represents a plate. A contact projection 310 is provided on the upper edge of each of the deposition electrodes 31 . Each deposition electrode 31 is guided from above through a through slot 304 in the first boundary wall 300 and extends through the receiving space 302 inside the holding device 30. The lower edge of the deposition electrode 31 is received in the guide groove 305. The contact projections 310 protrude beyond the top of the first boundary wall 300 and can thus be connected to contact means, for example a rail.

In the second embodiment, too, the holding device 30 can be in one piece or in two pieces. In particular, the boundary walls 300, 301 and the frame webs 303 can be formed in one piece up to an end of the through-slots 304 in the first boundary wall 300. A further part can then be attached to this part as a cover frame (not shown) and the through-slots 304 can thus be delimited.

In the two embodiments shown, the deposition electrodes 31 are preferably each provided with an insulating coating (not shown).

The invention is again generally described below. A fluid to be cleaned, which is in particular air, flows or streams through the electrostatic filter unit according to the invention, which can also be referred to as an electrostatic filter. The flow is preferably effected by a fan of a ventilation device on which the filter unit is provided. In this case, particles in the fluid are initially electrically charged within an ionization unit and later separated out in a separation unit. The separating unit is characterized by the fact that it contains an electrical field that is as homogeneous as possible. The electric field force (F) acts on the charged particles as they pass due to their charge parallel to the field lines of the deposition. The resulting acceleration deflects the particles from their path and after a discrete time t they hit the collecting electrodes. With this impact, the particles are considered separated. Due to the principle, the efficiency of the separation is at its maximum when the dwell time of the particles is greater than the maximum design path s.

The electrostatic filter unit according to the invention can be used to filter particles and air pollution down to the fine dust range of 1 μm. the filter unit according to the invention is optimized according to manufacturing aspects, costs and performance aspects.

The precipitation electrodes of the separating unit represent a blockage of the passing fluid volume flow. Due to the blockage, the fluid speed increases linearly to the blockage. This is equivalent to a reduction in the residence time t. Today's electrostatic filters compensate for these losses by lengthening the separation unit in order to increase the residence time. At the same time, the pressure loss at the separation unit increases with the increase in speed and the lengthening of the separation unit. The energy efficiency of the overall system is reduced by a higher obstruction.

In known electrostatic filters, arrays/rows of metal plates are usually provided, similar to a normal plate capacitor. The plates must be isolated from each other at least at their suspension point. Depending on the area of application and the conditions of use, an additional, full-surface insulation layer may be necessary for the electrodes in order to prevent flashovers. This increases the blockage.

In addition, the design effort and the production costs are high due to the large number of parts and the complex alignment of the plates.

The present invention no longer has these disadvantages or at least reduces these disadvantages.

With the present invention, a preferably one-part, but optionally also multi-part, form-fitting holding device is created, which can also be referred to as a frame or holding frame. The holding device consists of electrically conductive material and is used in a separating unit in the electrostatic filter unit, which can also be referred to as an electrostatic filter module. In doing so, the frame is connected to the earth of the connected high-voltage unit. The purpose of the frame is to accommodate and align the deposition electrodes, which can also be referred to as high-voltage electrodes. The frame itself has a high mechanical stability. At the same time, the frame forms the opposite pole to the high-voltage electrodes. In order to separate the frame and the high-voltage electrode electrically, the separating electrode can optionally be encased in insulation or the frame can be appropriately coated with an insulator.

Optionally, the counter-electrodes of the required ionization unit can also be attached to the inflow side, ie the front side, of the holding device. In this configuration, the effort involved in installing the ionization unit is further reduced. The only things that have to be created in addition to the holding device are wire receptacles and the contact to the high-voltage component.

The separating package consisting of the holding device and separating electrode(s) and the ionization unit are preferably integrated in an insulated outer housing.

In the filter unit according to the invention, since the holding device itself is connected to the ground of the high-voltage power source, the number of necessary components is reduced and, at the same time, the number of assembly steps is reduced.

In the embodiment of the filter unit in which a single separation electrode, in particular a positive flat conductor, is used and is threaded into the holding device, for example, the number of necessary contacts is further reduced. Apart from the power supply for the high-voltage unit, only two contacts then have to be installed in the filter unit. The fixture must be connected to earth and the flexible separator electrode to the positive output of the high voltage unit. This contacting is simpler than in known filter units, in which all collecting electrodes designed as plates, ie separating electrodes and counter-electrodes, must be connected in series to one another via rails or continuous cables and then connected to the high-voltage unit.

In the embodiment of the filter unit in which only one-sided through-slots and preferably guide grooves are provided opposite one another, the number of electrode plates of the separating unit is reduced compared to the known ones Filter units by half, since the holding device with the frame struts forms the counter-electrodes, but the frame struts no longer have to be inserted and contacted individually. Only the deposition electrodes, which are designed as plates, still have to be contacted in series and connected to the high-voltage supply. The advantage of this embodiment lies in the reduced number of components for the separating unit by 50%. The insertion of the plate that is still required is carried out on one side and is therefore easy to handle in terms of production technology.

The form-fitting connection of the holding device, in particular the first and second boundary wall through the frame webs, also results in enormous mechanical stability and the geometry has advantages in production using injection molding (conductive plastics, aluminum, etc.), since the form-fitting connection reduces distortion becomes.

Reference sign

1

filter unit

10

protective grid

2

ionization unit

20

counter electrode

3

separation unit

30

holding device

300

first boundary wall

301

second boundary wall

302

recording room

303

frame bridge

304

through slot

305

guide groove

306

renewal

307

Side wall

308

strut

309

cover frame

31

deposition electrode

310

contact projection

4

contact space

5

ventilation device

50

ventilation housing

51

flapper

52

intake port

6

hob

S

flow direction

Claims (17)

1. Electrostatic filter unit for a ventilation housing (5) comprising an ionisation unit (2) and a precipitation unit (3) having at least one precipitation electrode (31), wherein the precipitation unit (3) has a holding apparatus (30) for holding the at least one precipitation electrode (31), the holding apparatus (30) has a guiding geometry for the at least one precipitation electrode (31), and the holding apparatus (30) consists of an electrically conductive material, characterised in that the holding apparatus (30) comprises a first and a second delimiting wall (300, 301) and at least two frame webs (303) that lie between the first and the second delimiting wall (300, 301), that in each case a receiving compartment (302) for at least one part of a precipitation electrode (31) is formed between two adjacent frame webs (303) and that the guiding geometry has at least one through-slot (304) for a precipitation electrode (31) through one of the delimiting walls (300, 301).
2. Electrostatic filter unit according to claim 1, characterised in that the frame webs (303) extend parallel to one another in a perpendicular manner with respect to the first and second delimiting wall (300, 301) of the holding apparatus (30) and that the at least one through-slot (304) of the guiding geometry is provided in each case between two frame webs (303) in one of the delimiting walls (300, 301).
3. Electrostatic filter unit according to one of claims 1 or 2, characterised in that at least one through-slot (304) is provided in the first delimiting wall (300) and likewise at least one through-slot (304) that is aligned with the at least one through-slot (304) in the first delimiting wall (300) is provided in the second delimiting wall (301).
4. Electrostatic filter unit according to one of claims 1 to 3, characterised in that the edges of the at least one through-slot (304) are rounded.
5. Electrostatic filter unit according to one of claims 1 to 4, characterised in that the precipitation electrode (31) is formed by a band that extends through at least two receiving compartments (302) of the holding apparatus (30) in a perpendicular manner with respect to the first and second delimiting wall (300, 301).
6. Electrostatic filter unit according to claim 5, characterised in that the precipitation electrode (31) is a preformed component and has a meandering shape.
7. Electrostatic filter unit according to one of claims 1 to 6, characterised in that at least one through-slot (304) is provided in the first delimiting wall (300) and at least one guiding groove (305) that is aligned with the through-slot (304) of the first delimiting wall (300) is provided in the second delimiting wall (301).
8. Electrostatic filter unit according to one of claims 1 to 4, characterised in that the at least one precipitation electrode (31) is a planar plate and a precipitation electrode (31) is received at least in part in each receiving compartment (302).
9. Electrostatic filter unit according to one of claims 1 to 8, characterised in that the at least one precipitation electrode (31) is insulated over its entire surface apart from a contact region for making contact with a high voltage unit.
10. Electrostatic filter unit according to one of claims 8 or 9, characterised in that the at least one precipitation electrode (31) has as a contact region a contact protrusion (310) that protrudes outwards beyond the delimiting wall (300, 301) in which the at least one through-slot (304) is provided.
11. Electrostatic filter unit according to one of claims 1 to 10, characterised in that the holding apparatus (30) is insulated.
12. Electrostatic filter unit according to one of claims 1 to 11, characterised in that the at least one through-slot (304) terminates at a spacing with respect to the front side and rear side of the holding apparatus (30).
13. Electrostatic filter unit according to one of claims 1 to 12, characterised in that the holding apparatus (30) is constructed in two parts wherein one part comprises the delimiting walls (300, 301) having the provided guiding geometry and a further part represents a cover frame (309) that closes the guiding geometry to the front or to the rear.
14. Electrostatic filter unit according to one of claims 1 to 13, characterised in that in each case a plate-shaped extension (306) is arranged on the holding apparatus (30) on the front side of the first and the second delimiting wall (300, 301) and the plate-shaped extensions in each case extend into the ionisation unit (2) and form the counter electrodes of the ionisation unit (2).
15. Electrostatic filter unit according to one of claims 1 to 14, characterised in that the holding apparatus (30) has on a lateral edge of the delimiting walls (300, 301) a contact space (4) for contacting the at least one precipitation electrode (31) that consists of a non-conductive material.
16. Electrostatic filter unit according to one of claims 1 to 15, characterised in that the holding apparatus (30) is produced by an injection moulding method.
17. Ventilation apparatus characterised in that this comprises at least one electrostatic filter unit (1) according to one of claims 1 to 16.

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