EP2979602B1 - Back-flushable air filter - Google Patents

Description

The invention relates to a vacuum cleaner with a backwashable air filter according to the features of the preamble of claim 1.

Vacuum cleaners with backflushable air filters are known in the prior art. These are usually used to clean air contaminated with dust and / or dirt. In connection with vacuum cleaners, these are used to protect the blower of the vacuum cleaner from being covered with vacuumed up dust / dirt. Due to the suction operation of the vacuum cleaner, the filter element is regularly covered with dust. The filter element becomes dirty as the operating time increases, so that backwashing of the air filter is required at regular intervals.

The publication DE 195 17 197 A1 describes, for example, a backflushable air filter for a vacuum cleaner, which has a cleaning nozzle arranged in the filter element, which is flowed through for the purpose of cleaning by means of a compressor of the vacuum cleaner against the flow direction customary for filter operation. The compressor has two valve blocks, with the aid of which the flow direction can be changed from filter operation to backwash operation. The valve blocks must be switched over manually.

From the WO 2009/031961 A1 A backflushable air filter is known, in which the secondary air inlet path is arranged upstream of the clean air outlet area in the flow direction for filter operation. Both ways are equipped with a separate valve unit.

From the DE 10 2010 045 979 A1 a vacuum cleaner with a backwashable air filter is known, in which an active valve control, by means of lifting magnets, is provided for switching over between the suction operation and the backwash operation.

Starting from the last-mentioned prior art, the invention is concerned with the task of specifying a vacuum cleaner with a backwashable air filter, in which there is an advantageous switchability.

This object is achieved with the subject matter of claim 1, with the focus being on the valve element having a check valve which is arranged and designed such that it closes the clean air area when the air filter flows through it by means of an air flow flowing from the clean air space in the direction of the dust air space , A simple design is achieved. The valve element can also simultaneously close the clean air outlet and open the secondary air inlet path.

The air filter is designed so that it can be backwashed regardless of the type and design of the device, vacuum cleaner in which it is used. The ambient air required for backwashing is sucked into the air filter through the secondary air inlet path, so that it is not necessary to provide a compressor with corresponding valve blocks for switching the flow direction from the clean air outlet area in the direction of the dust air space.

It is proposed that the valve element close the clean air outlet area by means of an air stream flowing in a backwashing mode from the clean air room in the direction of the dust air room and to open at least one secondary air inlet path which connects the clean air room with the ambient air surrounding the air filter.

According to this embodiment, the air filter has a valve element which opens and closes depending on the direction of the air flow flowing through the air filter and thereby enables either filter operation or backwashing operation.

The air filter is switched from a filter operation to a backwash operation or vice versa by the flow direction of the air stream flowing through the air filter itself. In order to initiate the backwash operation, the air filter is connected to a suction fan from the direction of the dust air space. This is done, for example, by connecting the device in which the air filter is used, for example a vacuum cleaner, to a suction fan, for example the suction fan of a second vacuum cleaner. The design and arrangement of the valve element according to the invention prevent the suction air flow which arises when the air filter is extracted via the dust air space side from having an effect on the suction fan of the device which has the backwashable air filter and is not in operation. With the help of the valve element according to the invention, the suction fan is fluidically separated from the air filter, so that the suction fan cannot be set in rotation and damage to the electronics is therefore excluded. It is particularly advantageous that the valve element according to the invention simultaneously fulfills two different functions, namely, on the one hand, the closing the clean air outlet area in order to prevent the suction fan from rotating as well, and on the other hand to open a secondary air inlet path between the clean air space and the surroundings of the filter element, so that ambient air, which is required for cleaning the air filter, can be sucked into the clean air space.

It is proposed that the valve element be slidably arranged on the clean air outlet area, in particular in the clean air outlet area. It is particularly recommended that the valve element be arranged on or in the clean air outlet area such that it is displaced as a result of the air flow flowing from the clean air space in the direction of the dust air space. The geometric shape of the valve element can be adapted to the shape of the clean air outlet area. If the clean air outlet area is cylindrical, for example, the valve element can advantageously be a likewise cylindrical element which can be moved coaxially within the clean air outlet area.

It is recommended that the valve element and the clean air outlet area have mutually corresponding secondary air inlet openings, which can be arranged relative to one another by displacing the valve element relative to the clean air outlet area in such a way that a secondary air inlet path is opened. The valve element can thus be displaced relative to the clean air outlet area such that secondary air inlet openings correspondingly formed in the valve element and the clean air outlet area lie next to one another, so that ambient air can get into the clean air room. In the event that the valve element and the clean air outlet area are, for example, cylindrical elements, the valve element can be coaxial with the clean air outlet area be moved until the secondary air inlet openings lie next to each other in the radial direction and thus open up a secondary air inlet path for the ambient air. Both the valve element and the clean air outlet area can have a plurality of secondary air inlet openings or only one secondary air inlet opening each.

The valve element preferably has a check valve which is arranged and designed such that it closes the clean air outlet area when the air filter flows through by means of an air flow flowing from the clean air space in the direction of the dust air space. In this respect, the valve element closes the clean air outlet area automatically when the clean air space is flowed through in the opposite direction to the flow direction customary for filter operation. Depending on the properties of the check valve, the clean air outlet area is closed at a certain suction force of the air flow flowing in the direction of the dust air space, so that the air flow cannot act back on the suction fan.

It is particularly recommended that the check valve has at least one pivotable check valve. In this sense, two symmetrical non-return flaps can be arranged within the clean air outlet area, for example, which are swiveled in the direction of the clean air space, i.e. into the opening cross section of the clean air outlet area, as a result of the reversal of the flow direction when changing from a filter operation to a clean air outlet area, which closes the clean air outlet area ,

It is further provided that the valve element is connected to the clean air outlet area by means of a return element, in particular a spring, such that the valve element is displaced in the direction of the dust air space when the clean air outlet area is closed during a backwashing operation, counter to the restoring force of the return element and with the release of a secondary air inlet path. As a result of this particularly advantageous embodiment, the valve element is displaced in the direction of the dust air space when the check valve is closed. In this case, the suction force of the air flow acting on the valve element is used, which acts on the check valve, for example the pivotable check valves and tries to pull them in the direction of the dust air space, the entire valve element likewise being displaced in the direction of the dust air space. With the aid of the reset element arranged between the clean air outlet area and the valve element, it is ensured that a predefined pressure within the clean air outlet area is reached or fallen below before the valve element is displaced and thus ambient air can get into the clean air space through the secondary air inlet path. If the pressure is sufficient to open the secondary air inlet path, a balance is advantageously established between the amount of ambient air flowing into the clean air space and the amount of air sucked out of the backwashable air filter by means of the external suction fan. The restoring element can advantageously be a spring, but other restoring elements that serve the same purpose are also conceivable. If the external suction fan is switched off, the backwashable air filter is ventilated again and the valve element is moved back into its starting position by the restoring force of the restoring element, the secondary air inlet path also being closed again at the same time. As a result of the ventilation, the check valve arranged in the clean air outlet area is also simultaneously opened again, for example, the swiveling non-return flaps are swiveled back into an open position.

It is also provided that the valve element and a cleaning nozzle are arranged in relation to one another in the backwashing operation of the air filter in such a way that ambient air sucked in through the secondary air inlet path is forced into the cleaning nozzle. According to a particularly simple embodiment, the valve element can be displaced within the clean air outlet area in such a way that in a backwashing position it makes direct contact with the cleaning nozzle, so that the air drawn in through the secondary air inlet path can only flow into the cleaning nozzle and thus cleans the filter element. As an alternative to direct contact between the valve element and the cleaning nozzle, it can also be provided that the valve element and the cleaning nozzle rest against a common contact part, as a result of which a flow path into the cleaning nozzle is predetermined.

Finally, it is provided that the cleaning nozzle is a rotating air nozzle rotatably mounted in the clean air space. The cleaning nozzle has at least one nozzle opening pointing in the direction of the filter element, which is arranged and designed such that the outflowing air sets the cleaning nozzle in rotation and thus cleaning of the inner surface of the filter element can be carried out over the entire circumference. As an alternative to this, however, it can also be provided that the cleaning nozzle is a stationary nozzle which has such a large number of nozzle openings that cleaning with the entire circumferential surface is also possible.

The configuration enables the back-flushable air filter to be cleaned by bringing the suction mouth of the vacuum cleaner, for example, into contact with a suction mouth of a second vacuum cleaner. The backflushable air filter is then extracted immediately after the second vacuum cleaner is switched on, the dust collected in the filter element of the vacuum cleaner according to the invention being sucked into the second vacuum cleaner.

Fig. 1

eine perspektivische Darstellung eines Staubsaugers mit einem rückspülbaren Luftfilter während eines Filterbetriebs,

Fig. 2

eine perspektivische Darstellung des Staubsaugers gemäß Fig. 1 mit einem geschlossenen Rückschlagventil,

Fig. 3

eine perspektivische Darstellung des Staubsaugers gemäß Fig. 1 während eines Rückspülbetriebs,

Fig. 4

eine Prinzipskizze eines erfindungsgemäßen rückspülbaren Luftfilters während eines Filterbetriebs,

Fig. 5

eine Reinigungsdüse,

Fig. 6

eine Prinzipskizze des rückspülbaren Luftfilters gemäß Fig. 4 mit einem geschlossenen Rückschlagventil,

Fig. 7

eine Prinzipskizze des rückspülbaren Luftfilters gemäß Fig. 4 während eines Rückspülbetriebs.

The invention is explained in more detail below using an exemplary embodiment. Show it:

Fig. 1

1 shows a perspective view of a vacuum cleaner with a backwashable air filter during a filter operation,

Fig. 2

a perspective view of the vacuum cleaner according to Fig. 1 with a closed check valve,

Fig. 3

a perspective view of the vacuum cleaner according to Fig. 1 during a backwash operation,

Fig. 4

1 shows a schematic diagram of an air filter according to the invention which can be backwashed during a filter operation,

Fig. 5

a cleaning nozzle,

Fig. 6

a schematic diagram of the backwashable air filter according Fig. 4 with a closed check valve,

Fig. 7

a schematic diagram of the backwashable air filter according Fig. 4 during a backwash operation.

Fig. 1 shows a vacuum cleaner 1, namely a hand-held vacuum cleaner, with a backwashable air filter 2. The backwashable air filter 2 has a cylindrical filter element 3, in which a likewise cylindrical cleaning nozzle 6 with nozzle openings 7 for backwashing the filter element 3 is arranged during a backwashing operation. The air filter 2 has a valve element 9 with non-return flaps 13, which are opened in the filter operation shown, so that the filtered air arrives at a suction fan 16 of the vacuum cleaner 1.

Fig. 2 shows the in Figure 1 Air filter 2 shown with closed check valves 13th

Fig. 3 shows the in Figure 1 Air filter 2 shown during a backwashing operation. In the backwashing operation, the non-return flaps 13 are closed, the valve element 9 being displaced in the direction of the cleaning nozzle 6, so that secondary air inlet openings 11 are opened, through which ambient air can be drawn into the air filter 2 for cleaning the filter element 3.

Fig. 4 shows a detailed schematic diagram of the in Figure 1 shown backwashable air filter 2 in a filter operation. The filter cleans during operation backwashable air filter 2 the air sucked into the air filter 2 via a suction opening 15, which air is regularly exposed to dust and / or dirt. The backwashable air filter 2 has the filter element 3, which contains, for example, a material with filter properties, for example a fleece. The filter element 3 separates a clean air space 4 of the backwashable air filter 2 from a dust air space 8. The clean air space 4 is the portion of the air filter 2 which is in front of the filter element 3 in the direction of flow of the dust-laden air. The dust air space 8 is the area of the air filter 2 which lies behind the filter element 3 in the direction of flow of the air loaded with dust. The cleaning nozzle 6 with the nozzle openings 7 is arranged in the clean air space 4 of the air filter 2. There is no flow through the cleaning nozzle 6 during the filter operation of the air filter 2.

A clean air outlet area 5 is assigned to the clean air space 4, through which the air cleaned by means of the filter element 3 can reach a suction fan 16 of the vacuum cleaner 1. The suction fan 16 is not part of the air filter 2. On the clean air outlet area 5, here for example within the clean air outlet area 5, the valve element 9 is arranged, which is designed to close the clean air outlet area 5 for backwashing operation of the air filter 2 and at least one with the clean air space 4 the secondary air inlet path 10 connecting the ambient air. For this purpose, the valve element 9 has the secondary air inlet opening 11, which corresponds to a secondary air inlet opening 11 of the clean air outlet region 5. The valve element 9 also has a check valve 12, which in the present example has the two check valves 13. A reset element 14, here a spring, is arranged between the valve element 9 and the clean air outlet area 5.

Fig. 5 shows the cleaning nozzle 6, which can be used for cleaning the filter element 3 coaxially in the clean air space 4 of the air filter 2. The cleaning nozzle 6 has, for example, two nozzle openings 7, which extend in the form of a slot in the axial direction of the cleaning nozzle 6. The nozzle openings 7 have an air outlet direction, which essentially has an angle unequal to 0 ° with respect to the radial direction of the cleaning nozzle 6, so that the cleaning nozzle 6 is set in rotation when air flows through it.

Fig. 6 shows the backwashable air filter 2 according to Fig. 4 with closed check valves 13 (analog Fig. 2 ). The air filter 2 assumes this position when changing from a filter operation to a backwash operation. In this case, the air filter 2 is acted upon by a suction blower, for example the suction blower of a second vacuum cleaner, via the suction opening 15, so that the check valve 12 arranged in the clean air outlet area 5 closes. Here, the two check valves 13 of the check valve 12 are pivoted into the clean air outlet area 5, so that the clean air outlet area 5 is fluidically separated from the suction fan 16 of the vacuum cleaner 1. As an alternative to backwashing by means of the suction fan of a second vacuum cleaner, the suction fan of the same vacuum cleaner can of course also be used by switching it to the suction opening 15 of the air filter 2.

Fig. 7 shows that in the Figures 4 and 6 shown backwashable air filter 2 during the backwash operation (analog Fig. 3 ). During the backwashing operation, the check valve 12 is closed, the suction air flow of the external suction fan trying to pull the check valves 13 in the direction of the dust air space 8. This makes it movable at the clean air outlet area 5 arranged valve element 9 pulled in the direction of the cleaning nozzle 6, wherein the valve element 9 moves against the restoring force of the restoring element 14. The secondary air inlet openings 11 formed within the clean air outlet region 5 and the valve element 9 come next to one another with respect to a radial direction of the air filter 2, so that an air inlet path 10 is opened.

The air filter 2, as exemplified in Fig. 1 shown, integrated in a vacuum cleaner 1. The air filter 2 is installed in the vacuum cleaner 1 in such a way that it is arranged within its suction air path, that is to say between a suction mouth of the vacuum cleaner 1 and the suction fan 16 of the vacuum cleaner 1. The air filter 2 can be cleaned, that is to say backwashed, particularly advantageously as a result. by connecting a second vacuum cleaner to the suction mouth of the first vacuum cleaner 1.

In a normal use of the vacuum cleaner 1 for cleaning purposes, the backwashable air filter 2 is in the in the Fig. 1 and 4 filter operation shown. Air is sucked through the suction opening 15 of the air filter 2 by means of the suction fan 16 of the vacuum cleaner 1. The sucked-in air reaches the filter element 3 via the dust air space 8 of the air filter 2. The air to be filtered flows through the filter element 3, the dust contained in the air being filtered. The filtered air then flows past the (not in operation) cleaning nozzle 6 within the clean air space 4 without passing through it. Finally, the filtered air arrives from the clean air space 4 into the clean air outlet area 5 and to the suction fan 16. The clean air outlet area 5 is opened to clear the way to the suction fan 16. For this purpose, the valve element 9 is in an open position, the two non-return flaps 13 on the inner wall of the clean air outlet area 5 so that a maximum flow cross section of the clean air outlet area 5 is available.

Due to the progressive filter operation of the air filter 2, dust and dirt are deposited on the filter element 3. In order to maintain the suction power of the vacuum cleaner 1, it is therefore necessary to clean the air filter 2 by removing the dust and dirt from the filter element 3. For this purpose, the suction mouth of the vacuum cleaner 1 and thus also the suction opening 15 of the air filter 2 are connected in terms of flow technology to a suction blower, for example a suction blower of a second vacuum cleaner, which applies a vacuum to the suction opening 15. The resulting suction air flow in the direction of the suction opening 15 acts on the check valves 13 of the check valve 12, so that they are pivoted into the clean air outlet area 5 and close the clean air outlet area 5. This situation is in Fig. 6 shown.

When the air filter 2 is evacuated progressively via the suction opening 15, the force acting on the check valve 12 increases such that the valve element 9 is pulled in the direction of the cleaning nozzle 6. This situation is in Fig. 7 shown. The valve element 9 comes into operative connection with the cleaning nozzle 6 in such a way that the extracted air flow can only reach the suction opening 15 via the cleaning nozzle 6. Due to the displacement of the valve element 9 within the clean air outlet area 5, the corresponding secondary air inlet openings 11 of the valve element 9 and the clean air outlet area 5 are pushed next to one another in such a way that a secondary air inlet path 10 is opened. Through this secondary air inlet path 10, ambient air can now be sucked in from the surroundings of the air filter 2, which serves to clean the filter element 3. The sucked-in air passes from the secondary air inlet path 10 through the cleaning nozzle 6, the filter element 3 and finally the suction opening 15 to the suction fan. Because the nozzle openings 7 of the cleaning nozzle 6 are not aligned radially, but rather are at a certain angle unequal to 0 °, the cleaning nozzle 6 rotates as a result of air flowing through it. The rotation of the cleaning nozzle 6 rotates the nozzle openings 7 past the inner wall of the filter element 3, so that the filter element 3 can be cleaned over the entire circumference. The dust contained in the filter element 3 is released from the filter element 3 and reaches the suction opening 15 through the dust air space 8.

As soon as the air filter 2 is no longer subjected to negative pressure via the suction opening 15, the suction force acting on the check valve 12 drops. As a result, the restoring force of the restoring element 14 outweighs the suction force acting on the check valve 12, so that the valve element 9 is pulled back into its starting position for filter operation. By moving the valve element 9 within the clean air outlet area 5, the secondary air inlet openings 11 are shifted towards each other again, so that the secondary air inlet path 10 is also blocked at the same time. Likewise, the valve element 9 is also separated from the cleaning nozzle 6, so that the direct path between the filter element 3 and the clean air outlet area 5 is cleared again without the detour via the cleaning nozzle 6.

The air filter 2 thus cleaned can now be used again for filter operation.

LIST OF REFERENCE NUMBERS

1

vacuum cleaner

2

air filter

3

filter element

4

Clean air chamber

5

Reinluftauslassbereich

6

cleaning nozzle

7

nozzle opening

8th

Dust airspace

9

valve element

10

Nebenlufteinlassweg

11

In addition to air inlet opening

12

check valve

13

check valve

14

Return element

15

suction opening

16

aspirator

Claims (7)

1. Vacuum cleaner (1) comprising a backwashable air filter (2), the air filter (2) having a filter element (3) which separates a dust air chamber (8) from a clean air chamber (4) and through which, in a filter operation, air to be cleaned flows from the dust air chamber (8) towards the clean air chamber (4), a clean air outlet region (5) being associated with the clean air chamber (4) and the clean air outlet region (5) having a valve element (9) which is designed to make it possible, in a backwashing operation as a result of opening a secondary air inlet path (10), for the filter element (3) to be backwashed using ambient air, and in addition the secondary air inlet path (10) being downstream of the clean air outlet region (5) in the flow direction for a filter operation, characterised in that the valve element (9) has a check valve (12) which is arranged and designed in such a way that this seals the clean air outlet region (5), when air flows through the air filter (2), by means of an airflow flowing from the clean air chamber (4) towards the dust air chamber (8).
2. Vacuum cleaner (1) according to claim 1, characterised in that the valve element (9) is designed to seal the clean air outlet region (5) by means of an airflow flowing in a backwashing operation from the clean air chamber (4) towards the dust air chamber (8) and to release at least one secondary air inlet path (10) which connects the clean air chamber (4) to the ambient air surrounding the air filter (2).
3. Vacuum cleaner (1) according to either claim 1 or claim 2, characterised in that the valve element (9) is slidably mounted on the clean air outlet region (5), in particular in the clean air outlet region.
4. Vacuum cleaner (1) according to any of the preceding claims, characterised in that the valve element (9) and the clean air outlet region (5) have mutually corresponding secondary air inlet openings (11) which, by sliding the valve element (9) relative to the clean air outlet region (5), can be arranged with respect to one another in such a way that a secondary air inlet path (10) is released.
5. Vacuum cleaner (1) according to any of the preceding claims, characterised in that the valve element (9) is connected to the clean air outlet region (5) by means of a restoring element (14), in particular a spring, in such a way that the valve element (9), when the clean air outlet region (5) is sealed during a backwashing operation, is slid, against the restoring force of the restoring element and with a secondary air inlet path (10) being released, towards the dust air chamber (8).
6. Vacuum cleaner (1) according to any of the preceding claims, characterised in that the valve element (9) and a cleaning nozzle (6), in the backwashing operation of the air filter (2), are arranged with respect to one another in such a way that ambient air sucked in through the secondary air inlet path (10) is forced into the cleaning nozzle (6).
7. Vacuum cleaner (1) according to any of the preceding claims, characterised in that the cleaning nozzle (6) is a rotatably mounted rotational air nozzle in the clean air chamber (4).

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