Filter Arrangement and Method

Abstract

The invention relates to a filter arrangement comprising a filter cartridge, having an opening and a wall which is formed by a filter medium and has an inner side delimiting a clean side of the filter and an outer side delimiting a raw side of the filter, a fan for conveying air to be purified first through the wall and subsequently through the opening of the filter cartridge, and a purification device, which is configured to convey a jet of compressed air through the opening into the filter cartridge and through the out of the filter cartridge, for conveying dirt away from an outer wall of the wall. The invention also relates to a method for detecting a leak of a filter cartridge, wherein the filter cartridge has an opening and a wall which is formed by a filter medium and has an inner side delimiting a clean side of the filter and an outer side delimiting a raw side of the filter.

Claims

1. A filter arrangement comprising a filter cartridge, having an opening; and a wall which is formed by a filter medium and has an inner side delimiting a clean side of the filter and an outer side delimiting a raw side of the filter, a fan for conveying air to be purified first through the wall and subsequently through the opening of the filter cartridge, a purification device, which is configured to convey a jet of compressed air through the opening into the filter cartridge and through the wall out of the filter cartridge, for conveying dirt away from an outer wall of the wall, and a sensor configured to determine a force acting on a measurement region on the basis of the jet of compressed air.

2. The filter arrangement according to claim 1, wherein the measurement region is one of opposite the opening in the filter cartridge or arranged at an end of the filter cartridge opposite the opening.

3. The filter arrangement according to claim 1, wherein the sensor is designed as a piezo element, as a membrane, as an elastomer film, as a strain gauge, for measuring a differential pressure on the inflow and outflow side, as a differential pressure sensor for determining the differential pressure between an interior of the filter cartridge and the surroundings of the filter cartridge, as a microphone and/or as an optical sensor.

4. The filter arrangement according to claim 1, wherein the filter cartridge is formed of at least two filter elements, each with a wall formed of the filter medium, with an inner side delimiting the clean side of the filter and an outer side delimiting the raw side of the filter, wherein the outer sides of the filter elements form the outer side of the filter cartridge, the measurement region is one of arranged in a filter element of the filter cartridge or in the filter element distanced furthest from the opening of the filter cartridge, and the filter element has a the sensor.

5. The filter arrangement according to claim 1, wherein the measurement region is arranged on a carrier plate that is removable from the filter cartridge and has the sensor.

6. The filter arrangement according to claim 1, with a computer-based control unit which is configured to receive and to analyse signals transmitted by the sensor, to determine, on the basis of a change of the sensor signal, a change to the force acting on the measurement region as a result of a jet of compressed air so as to detect a leak in the filter cartridge, and/or to determine, on the basis of the change to the sensor signal, that the filter cartridge needs replacing.

7. The filter arrangement according to claim 6, wherein the sensor is designed as part of a sensor unit which additionally comprises the computer-based control unit.

8. The filter arrangement according to claim 7, wherein the sensor unit comprises at least one further sensor for detecting an ambient value or for detecting temperature and/or air humidity.

9. The filter arrangement according to claim 7, with a plurality of filter cartridges and a plurality of sensor units, wherein each sensor unit has a communications device designed at least for one of wireless transmission, in accordance with a WLAN, RFID, ZigBee, Z-wave and/or Bluetooth standard, of a dataset generated by the control unit.

10. The filter arrangement according to claim 9, wherein each communications device is positioned on a filter cartridge in such a way that a main transmission power is oriented orthogonally to a direction of arrangement of the filter cartridges.

11. The filter arrangement according to claim 9, wherein each sensor unit has a battery and is configured such that the corresponding communications device transmits the dataset only if a leak of the corresponding filter cartridge is determined and/or if it is determined that the corresponding filter cartridge has to be replaced or after a fixed time interval and/or once an output request has been received.

12. The filter arrangement according to claim 9, wherein a receiving device (14) for receiving datasets of the communications devices) is provided and is configured to determine the transmission position of a communications device on the basis of a corresponding signal strength and/or signal coding.

13. The filter arrangement according to claim 6, with a plurality of filter cartridges and a plurality of sensors each with an associated measurement region, wherein the computer-based control unit is configured to receive and to evaluate all signals transmitted by the plurality of sensors, to determine, on the basis of a change of a sensor signal, a change to the force acting on the corresponding measurement region as a result of a jet of compressed air so as to detect a leak in the corresponding filter cartridge, and/or to determine, on the basis of the change to the corresponding sensor signal, that the filter cartridge needs replacing.

14. A method for detecting a leak of a filter cartridge, wherein the filter cartridge has an opening and a wall which is formed of a filter medium and which has an inner side delimiting a clean side of the filter and an outer side delimiting a raw side of the filter, said method having the steps of: supplying a jet of compressed air through the opening into the filter cartridge and determining a force acting on a measurement region as a result of the jet of compressed air.

15. The method according to claim 14, with the steps of: transmitting a sensor signal, which is generated by a sensor on account of the jet of compressed air, to a control unit, and determining, by the control unit, a change to the force acting on the measurement region as a result of the jet of compressed air so as to detect a leak of the filter medium, and/or determining, by the control unit, on the basis of the change to the force acting on the measurement region, that the filter cartridge needs replacing.

16. The method according to claim 15, with the steps of: generating a dataset with information regarding a state of the filter cartridge by the control unit and transmitting the dataset by a communications device to a receiving device (14) if: an output request was received beforehand by the communications device, and/or a leak of the filter medium was detected by the control unit, and/or it has been determined by the control unit that the filter cartridge needs replacing.

17. The method according to claim 14, wherein the sensor is designed as a piezo element, as a membrane, as an elastomer film, as a strain gauge, for measuring a differential pressure on the inflow and outflow side, as a differential pressure sensor for determining the differential pressure between an interior of the filter cartridge and the surroundings of the filter cartridge, as a microphone and/or as an optical sensor.

18. The method according to claim 14, having a plurality of filter cartridges and a plurality of sensors.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The invention will be explained in greater detail hereinafter on the basis of embodiment examples with reference to the accompanying drawings.

[0049] In the drawings:

[0050] FIG. 1 shows a filter arrangement according to a preferred embodiment example of the invention in a schematic sectional view,

[0051] FIG. 2 shows a filter arrangement according to a further preferred embodiment example of the invention in a schematic sectional view,

[0052] FIG. 3 shows a filter cartridge of the filter arrangement according to FIG. 1 or 2 according to a preferred embodiment example of the invention in a schematic sectional view,

[0053] FIG. 4 shows the filter cartridge according to FIG. 3 according to the preferred embodiment example of the invention in a further schematic sectional view,

[0054] FIG. 5 shows a filter cartridge of the filter arrangement according to FIG. 1 or 2 according to a further preferred embodiment example of the invention in a schematic sectional view,

[0055] FIG. 6 shows a filter cartridge of the filter arrangement according to FIG. 1 or 2 according to an alternative embodiment example of the invention with a hose filter in a schematic sectional view, and

[0056] FIG. 7 shows a time graph in which a differential pressure of the filter cartridge according to FIG. 3 according to the preferred embodiment example of the invention is plotted above the volume flow and below.

DETAILED DESCRIPTION OF THE EMBODIMENT EXAMPLES

[0057] FIGS. 1 and 2 each show a filter arrangement in a filter housing 1 according to a preferred embodiment example of the invention ins a schematic view. The filter arrangement has a plurality of filter cartridges 2, which are connected in parallel in the filter housing 1 to filter out particles from an airflow—the flow direction of the airflow is symbolised by arrows—and are held adjacently in a separator plate 15 in a line-up direction 50. FIG. 1 shows five filter cartridges 2 connected in parallel, whereas seven filter cartridges 2 connected in parallel are shown in FIG. 2. The filter cartridges 2 shown on the left in FIG. 2 are formed by two filter elements 20 each, whereas the filter cartridges 2 shown on the right in FIG. 2 are formed by just one filter element 20.

[0058] The filter cartridges 2, as shown in FIGS. 2 to 5 in different exemplary embodiments in schematic sectional view, are each provided in the form of a cylindrical container with an opening 30 in their upper side 3 formed by an upper end plate 35, a closed lower side 4 in the form of a lower end plate 36, and a wall 5 formed from a filter medium 5a extending between the upper side 3 and the lower side 4. Excluding the edges at the upper side 3 and at the lower side 4, the filter medium 5a runs around the entire side of the filter cartridge 2 and in this way forms the lateral surface of the cylinder. The wall 5 has folds in order to form the filter medium 5a, which folds extend between an inner wall and an outer wall of the wall 5 and are separated from one another by means of beads. A fan 6 provided on the filter housing 1 sucks the air that is to be purified through the wall 5 into an interior of the filter cartridge 2 and then out of the filter cartridge 2 through the opening 30 in the upper side 3.

[0059] In order to transport away any dirt deposited on the outer wall of the filter medium 5a, the filter arrangement has a purification device 7 in the form of a plurality of nozzles 70 and a compressed air source 75. The purification device 7 is arranged above the filter cartridges 2, wherein the nozzles 70 are designed to transport a jet of compressed air, indicated in FIG. 3, through the opening 30 into the relevant filter cartridge 2 and through the wall 5 out of the filter cartridge 2. Any dirt deposited on the outer side of the wall 5 is “blasted” radially outwardly by means of such a jet of compressed air delivered periodically by the purification device 7 and falls to the bottom in a collection container 8 of the filter arrangement. In this case, the four nozzles 70′ shown in FIG. 2 are arranged statically above the filter cartridges 2 and deliver pulses of compressed air at defined time intervals, whereas the right nozzle 70″ is designed as a movable nozzle which injects compressed air continuously and is moved continuously over the three right filter cartridges 2 in order to form the pulses of compressed air. The static nozzles 70′ do not all deliver their pulses of compressed air simultaneously, but staggered over time.

[0060] The lower side 4 of the filter cartridge 2 in FIG. 2 is designed as a carrier plate 90 removable from the wall 5 or lower side 4 thereof. A sensor 9 is integrated on the carrier plate 90 so as to determine a force acting on a measurement region 40 formed on the lower side 4 on account of the jet of compressed air. In the embodiment shown in FIGS. 3 and 4, the sensor 9 is designed as a membrane, specifically as a stretchable elastomer film with flexible electrodes, the upper side of which facing the inner side forms the measurement region 40. By deformation of the elastomer film, indicated in FIGS. 3 and 4, the electrical capacitance of the membrane changes, such that the force acting on the measurement region 40 and thus the intensity of the jet of compressed air is determinable. The sensor signal may be transferred via a contact 100 to a control unit 13 (not shown). The sensor 9 is also supplied with power via the contact 100.

[0061] Alternatively, the lower side 4 may also be designed rigidly with a piezo element oriented towards the interior of the filter cartridge 2 as sensor 9. In addition, further sensors (not shown), such as moisture sensors and/or temperature sensors are provided for determining the moisture and/or the temperature. FIG. 5 shows a further embodiment of the sensor 9 as a strain gauge for measuring a differential pressure on the inflow and outflow side directly on the filter cartridge 2. To this end, the strain gauge is provided in a lower end plate 36 of the filter cartridge 2, where it may be moulded. The stretching of the sensor 9 is thus dependent on the stretching of the lower end plate 36 and the measurement region 40 corresponds to the surface of the lower end plate 36 lying in the filter cartridge 2. The sensor 9 may also be designed as a differential pressure sensor for determining the differential pressure between the interior of the container and the surroundings of the container.

[0062] The filter cartridge 2 also has a communications device 10 which is integrated in the lower end plate 36 and which is designed to wirelessly transmit the determined force in accordance with a WLAN, RFID and/or Bluetooth standard. A battery 11 and also a control unit 13 with an internal memory for evaluating and storing the determined force are additionally provided in the lower end plate 36, which control unit is connected to the communications device 10 and also the sensor 9. A receiving device 14 is additionally provided in the filter arrangement and receives the datasets sent from the communications device 10. The lower end plate 36 with battery 11, sensor 9, control unit 13 and communications device 10 forms a sensor unit 95. The sensor unit 95 may also be formed on a removable carrier plate 90, as shown in FIG. 2. The sensor unit in FIG. 2 comprises only the sensor 9, a battery 11 and a communications device 10, whereas the control unit 13 is formed centrally outside. A signal device 110 may display a fault to a user. If the sensor unit 95 is formed on a carrier plate 90 removable from the wall 5, as shown in FIG. 2, the battery 11 may be replaced easily or existing filter cartridges 2 may be retrofitted with a sensor unit 95 of this kind. The plurality of filter cartridges 2 of the filter arrangement are connected to a computer-based control unit 13, installed in a remote control centre, for communication with said control unit, which received and evaluates the sensor signals transmitted by the various communications devices 10 via a receiving device 14.

[0063] An alternative embodiment of a filter cartridge 2 of the filter arrangement according to FIG. 1 or 2 with a hose filter is shown in FIG. 6 in a schematic sectional view. In this case, the wall 5 is formed by a filter medium 5a surrounding the filter cartridge 2 apart from on the upper side 4. The filter cartridge 2 is held in a separator plate 15 by means of a compressed sealing region 34. A support cage 19 is introduced into the filter cartridge 2, with the sensor 9 being held thereon in a position opposite the opening 30 in the filter cartridge 2. The sensor 9 is designed as a microphone, the upper side of which forms the measurement region 40, and is connected to a control device 13, which in turn is connected to a communications device 10. In addition, a battery 11 is provided on the support basket 19 to supply power to the sensor 9, the control unit 13 and the communications device 10.

[0064] FIG. 7 shows a time graph, in which the volume flow is shown at the top and the differential pressure measured by the sensor 9 is shown at the bottom, in each case over time. Accordingly, the time is plotted on the abscissa and the differential pressure on the ordinate. The differential pressure rises periodically during filter operation, in each case to a maximum. The differential pressure in cleaning operation then drops, caused by the jet of compressed air purifying the filter cartridge 2, to a negative value, which is plotted accordingly as negative amplitude of the pressure.

[0065] In the event of a leak 5b in the filter medium 5a, indicated in FIG. 4 in the wall 5 shown in the right and in FIG. 7 where the axes cross over time, the volume flow through the filter cartridge 2 increases on the one hand. On the other hand, the negative amplitude of the pressure reduces. The reduction of the negative amplitude corresponds to the change in the force acting on the sensor 9 as a result of the jet of compressed air. The control unit 13 is designed to detect such a change or the reduced negative amplitude, so that a leak 5b of the relevant filter medium 5a may thus be determined and the need to replace the filter cartridge 2 is identifiable.

[0066] The described embodiment examples are merely examples and may be modified and/or supplemented in a wide range of ways within the scope of the claims. Any feature that has been described for a specific embodiment example may be used independently or in combination with other features in an arbitrary other embodiment example. Any feature that has been described for an embodiment example of a specific category may also be used accordingly in an embodiment example of another category.

LIST OF REFERENCE SIGNS

[0067] Filter housing 1 [0068] Filter cartridge 2 [0069] Upper side 3 [0070] Lower side 4 [0071] Wall 5 [0072] Filter medium 5a [0073] Leak 5b [0074] Fan 6 [0075] Purification device 7 [0076] Collection container 8 [0077] Sensor 9 [0078] Communications device 10 [0079] Battery 11 [0080] Control unit 13 [0081] Receiving device 14 [0082] Separator plate 15 [0083] Support basket 19 [0084] Filter element 20 [0085] Opening 30 [0086] Sealing region 34 [0087] Upper end plate 35 [0088] Lower end plate 36 [0089] Measurement region 40 [0090] Line-up direction 50 [0091] Nozzle 70/static nozzle 70′/moving nozzle 70″ [0092] Compressed air source 75 [0093] Carrier plate 90 [0094] Sensor unit 95 [0095] Contact 100 [0096] Signal device 110