METHOD FOR OPERATING A VACUUM DEVICE AND VACUUM DEVICE

Description

[0001] The invention relates to a method for operating a suction device which comprises a suction unit and a removable filter device, wherein the suction unit generates a suction flow which flows through the filter device when it is arranged on the suction device, in which method, after commissioning of the suction unit, it is checked whether the filter device is present, and if it is then detected that the filter device is not present, the suction unit is switched off, wherein an evaluation unit uses test data and determines from this whether a switch-off signal for the suction unit should be generated or not.

[0002] The invention further relates to a suction device comprising a suction unit and a removable filter device, wherein the suction unit generates a suction flow which flows through the filter device when the filter device is arranged on the suction device, a pressure sensor device which is arranged between the filter device and the suction unit and provides pressure measurement values ​​on the suction flow downstream of the filter device and upstream of the suction unit, and an evaluation unit which, after commissioning of the suction unit, determines on the basis of the measurement data of the pressure sensor device whether the filter device is inserted or not, and upon detection of a missing filter device, generates a switch-off signal for the suction unit.

[0003] US 4,733,430 discloses a vacuum cleaner with a dust bag sensor.

[0004] US 4,733,431 also discloses a vacuum cleaner with a dust bag sensor.

[0005] EP 2 636 351 A1 discloses a robot vacuum cleaner with a detection unit for a filter.

[0006] EP 2 598 008 B1 discloses a vacuum cleaner having a receiving space for a main filter, comprising a pressure sensor system for detecting a variable characterizing a negative pressure in a first region located downstream of the receiving space in the suction flow direction, a detection unit that detects, depending on the detected variable, whether a main filter is inserted, and a control unit that prevents operation of the vacuum cleaner and / or outputs thermal information to an operator of the vacuum cleaner if it is detected that no main filter is inserted. The pressure sensor system comprises at least one pressure switch that transmits an output signal to the detection unit when the negative pressure in the first region is above a predeterminable negative pressure threshold value, and the detection unit detects that no main filter is inserted if no output signal is received from the pressure switch.

[0007] US 2007 / 0283521 A1 discloses a programmable control unit for a vacuum cleaner system.

[0008] US 2007 / 0163075 A1 discloses a vacuum cleaner.

[0009] JP 03168117 A discloses a vacuum cleaner with an automatic stop function.

[0010] DE 10 2011 052 020 A1 discloses a vacuum cleaner with a means for detecting a measure of a volume flow generated during operation and / or with a means for detecting a measure of a negative pressure generated during operation, wherein a drive unit control comprises means for comparing the detected volume flow and a predetermined or predeterminable upper volume flow limit and / or means for comparing the detected negative pressure and a predetermined or predeterminable negative pressure limit and the drive unit control comprises or controls means for reducing the electrical power consumption depending on the result of the comparison.

[0011] The invention is based on the object of providing a method of the type mentioned at the outset with which the suction device can be operated safely.

[0012] This object is achieved according to the invention in the method mentioned at the outset in that the evaluation unit uses an algorithm or a table to make a decision regarding switching off the suction unit from the test data, and that the table contains at least one threshold value or the algorithm determines at least one threshold value, wherein the at least one threshold value is a threshold value for switching off the suction unit.

[0013] A filter system installed on the vacuum cleaner prevents sucked-in dust from being blown out into the environment. The filter system can become clogged with dust particles. There have been cases where operators have removed the filter system from the vacuum cleaner and then continued to operate the vacuum cleaner without the filter system.

[0014] This results in dust particles being blown into the environment. This is particularly critical when working with hazardous dust.

[0015] Without a filter device in place, dust particles can reach the suction unit and settle there.

[0016] Furthermore, especially if the filter device also has a sealing function, the suction operation can be significantly restricted because the full suction power is no longer available due to the lack of sealing by the filter device (due to the drawing in of false air).

[0017] With the solution according to the invention, after the vacuum cleaner is put into operation, a check is carried out to determine whether the filter device is present at all. If the check results show that it is not present, the vacuum unit is shut down. This prevents, in particular, dust particles from being blown into the room air.

[0018] By performing the test after commissioning the suction unit, the corresponding test device can be implemented in a simple design. The number of required components can be kept to a minimum. In particular, existing components can be used for the test. The filter device does not need to be modified.

[0019] An evaluation unit is provided which uses test data to determine whether or not a shutdown signal should be generated for the suction unit. This makes it easy to perform a detection test for the filter device. The test data includes, in particular, pressure measurements on a suction line between the filter device and the suction unit. Furthermore, an electrical voltage of a power source for the suction unit can also be taken into account. It is also possible, for example, to further consider the electrical power consumption of the suction unit.

[0020] The evaluation unit uses an algorithm or a table to make a decision regarding shutting down the suction unit based on the test data. This allows the corresponding test procedure to be implemented easily. The number of hardware components (such as switches and cables) can be kept to a minimum.

[0021] The table contains at least one threshold value, or the algorithm determines at least one threshold value, wherein the at least one threshold value is a threshold value for shutting down the suction unit, and in particular is a pressure value, wherein shutting down the suction unit preferably occurs when the absolute pressure value is too high relative to the threshold value. An absolute pressure value that is too high or a pressure difference that is too small relative to the ambient pressure is an indication of a missing filter device.

[0022] It is advantageous to wait a specific time interval after commissioning the suction unit before using test results to shut down or continue operating the suction unit. This specific time interval is determined so that stable values ​​can be established for testing, and in particular, stable pressure values ​​can be established. The time interval is selected to be at least long enough for these stable values ​​to be established, and is preferably short enough to minimize the commissioning time of the suction unit in relation to the detection of a missing filter device.

[0023] It has been shown that the specific time interval should be at least 2.5 s, preferably at least 3 s, and in particular at least 3.5 s. For example, this specific time interval is 4 s or 5 s. The specific time interval is also at least approximately the time interval that represents the maximum operating time of the suction unit when a missing filter device is detected.

[0024] From a design perspective, it is advantageous to perform the check for the presence of the filter device on the suction flow. This allows for reliable detection of the presence or absence of a filter device with minimal design effort.

[0025] In particular, the test is based on measured pressure values ​​in the suction flow between the filter device and the suction unit. These measured pressure values ​​can be used to detect the presence or absence of the filter device.

[0026] It is advantageous if the pressure measurements are determined at one or more points relative to the suction flow above a holder for the filter device, whereby these points are located above the filter device when the filter device is inserted on the holder. In particular, the corresponding measurement is carried out on a suction line which connects the filter device to the suction unit in a flow-effective manner relative to the suction flow. In one embodiment, it is provided that the point or points at which pressure measurements are determined lie outside the area affected by a cleaning device for the filter device. A clogged filter can be cleaned via the cleaning device, such as an external air valve device, in order to achieve improved flow throughput.By positioning the pressure sensor device accordingly, it can be prevented that a cleaning action via mechanical forces and / or pressure pulses for the filter device at least directly hits the pressure sensor device.

[0027] It has proven beneficial to use an electrical voltage applied to a power source for the suction unit to check for the presence or absence of the filter. For example, if the electrical power source for the suction unit is a public electrical grid, voltage fluctuations may occur. It has been shown that taking these voltage fluctuations into account enables improved detection of the presence or absence of the filter device.

[0028] The evaluation unit is connected to a control system for the suction unit or is part of this control system. This results in a simple design. In particular, the evaluation unit is implemented, at least for the most part, in software within the control system.

[0029] Ideally, the evaluation unit uses an algorithm or a table to make a decision regarding shutting down the suction unit based on the test data. This allows the corresponding test procedure to be implemented easily.

[0030] It is advantageous if the table contains at least one threshold value or the algorithm determines at least one threshold value, wherein the at least one threshold value is a threshold value for shutting down the suction unit, and in particular is a pressure value, wherein shutting down the suction unit preferably occurs when the absolute pressure value is too high relative to the threshold value. An absolute pressure value that is too high or a pressure difference that is too small relative to the ambient pressure is an indication of a missing filter device.

[0031] It has proven advantageous if the table includes threshold values ​​for different electrical voltages of an (electrical) energy source for the suction unit, or if the algorithm determines threshold values ​​for such different electrical voltages. It has been shown that this can also detect voltage fluctuations in a power grid, for example, so that such voltage fluctuations do not affect filter detection.

[0032] It has also proven advantageous if the table includes threshold values ​​for different power consumptions of the suction unit, or if the algorithm includes such threshold values ​​for different power consumptions of the suction unit, or if the algorithm determines such threshold values ​​for different power consumptions of the suction unit, and in particular, a classification is made based on a minimum power consumption and maximum power consumption of the suction unit. This results in a broad range of applications for filter detection. In particular, such a test can then be carried out largely independently of connected accessories (and in particular suction hoses). For example, it has been proven that threshold values ​​can then be specified that are largely independent of the diameter of a connected suction hose.

[0033] In one embodiment, threshold values ​​are determined from measurements in which suction hoses of different diameters are connected to the suction device and pressure readings are taken with and without the filter device in place. A threshold value with a "lowest common denominator" is then determined from these measured values.

[0034] It has proven advantageous to use different electrical voltages of an energy source for the suction unit when determining the threshold values ​​in order to be able to determine the influence of voltage fluctuations and, if necessary, to take them into account.

[0035] For the same reason, it is advantageous to use different power consumptions for the suction unit when determining the threshold values, and in particular to use a minimum power consumption and a maximum power consumption. This results in threshold values ​​that can be dependent, at least to some extent, on the power consumption.

[0036] In one embodiment, an installed filter device has a sealing function at a transition to a dirt collection container. This affects the threshold value. If the filter device is missing, leakage currents, etc., can occur. This results in a reduced negative pressure in the suction flow compared to an installed filter device, or the absolute pressure value is closer to the ambient pressure.

[0037] It is also possible for the evaluation unit to initiate measures based on the acquired test data if the presence of a filter device is detected. If the presence of a filter device is detected, the suction unit can continue to operate. Such measures can then include: initiating cleaning of the filter device by a cleaning device and / or generating a maintenance signal if a threshold value for a volume flow is undershot. If, for example, a pressure curve is then measured over time, clogging of the filter device with dust particles can be detected. The filter can then be cleaned as needed, for example when a threshold value is reached.Furthermore, for example, a maintenance signal can be generated which indicates another problem, such as blockage of the suction hose, if a threshold value for a volume flow is undershot, whereby this can generally be determined from the pressure measurements.

[0038] The object mentioned at the outset is achieved according to the invention in the suction device mentioned at the outset in that the evaluation unit comprises a memory device which stores threshold values ​​or data for an algorithm for threshold values, the threshold values ​​being threshold values ​​for switching off the suction unit.

[0039] This suction device has the advantages already explained in connection with the method according to the invention.

[0040] Further advantageous embodiments of the suction device according to the invention have already been explained in connection with the method according to the invention.

[0041] In particular, the evaluation unit includes a timer that ensures that a shutdown signal only becomes effective after a specific time interval has elapsed after the suction unit has been started up. This specific time interval is stored in the evaluation unit and is preferably determined or set at the factory.

[0042] The evaluation unit includes a memory device that stores threshold values ​​or data for a threshold value algorithm, where the threshold values ​​are, in particular, pressure values. This allows for simple filter detection. The number of hardware components can be kept to a minimum. In particular, no pressure switch with corresponding lines is required. A significant portion of the detection can be implemented using software.

[0043] It is also advantageous if the evaluation unit includes a device for detecting the electrical voltage at an electrical power source for the suction unit. This allows, for example, voltage fluctuations in a public power grid to be taken into account, and filter detection can be carried out reliably despite such possible fluctuations.

[0044] Furthermore, the evaluation unit may include a device for determining the power consumption of the suction unit and, in particular, divides the power consumption into a maximum power consumption or a minimum power consumption. This results in a reliable detection result.

[0045] In particular, the evaluation unit is connected to a control system of the suction device (which also serves as a control system for the suction unit) or is part of this control system. This allows the check for the presence of the filter device to be integrated into the control system of the suction device.

[0046] The suction device according to the invention can be used to carry out the method according to the invention or the method according to the invention can be carried out on the suction device according to the invention.

[0047] The following description of preferred embodiments of the invention, in conjunction with the drawings, serves to explain the invention in more detail. They show: Figure 1 shows a schematic representation of an embodiment of a suction device according to the invention; and Figure 2 shows a schematic representation of an embodiment of an evaluation unit for the suction device according to Figure 1 (in block diagram representation).

[0048] One embodiment of a vacuum cleaner 10 according to the invention is a stand-alone vacuum cleaner. This vacuum cleaner 10 has a dirt collection container 12. It is provided that the dirt collection container 12, and thus the vacuum cleaner 10 as a whole, can be mounted on a base via a caster 14 and a wheel assembly 16.

[0049] A detachable suction head 18 is mounted on the dirt collection container 12.

[0050] For example, a suction inlet 20 is arranged on the dirt collection container 12. In an alternative embodiment, the suction inlet 20 is arranged on the suction head 18. A suction hose 22 can be connected to this suction inlet 20; when the vacuum cleaner 10 is in suction mode, the material to be sucked in is sucked in via a connected suction hose 22 (which may also have a nozzle attached).

[0051] The suction head 18, when attached to the dirt collection container 12, seals the top of the container. It has a suction outlet 24, at which a filter device 26 with (at least) one filter is positioned on a filter holder 27. The filter holder 27 is designed, for example, as a surrounding element or as a base plate.

[0052] The filter device 26 is connected to (at least) one suction line 28. The suction line 28 leads to a suction unit 30. The suction unit 30 comprises a blower device 32 with (at least) one blower wheel and a drive motor 34 for motor-driven driving of the blower wheel of the blower device 32. The drive motor 34 is, in particular, an electric motor, such as a universal motor.

[0053] The suction line 28 and the suction unit 30 are arranged in the suction head 18.

[0054] In the described embodiment, the filter device 26 is arranged in the suction head 18.

[0055] In principle, it is also possible for the filter device 26 to be arranged on the dirt collecting container 12.

[0056] The suction unit 30 generates a suction flow via the blower device 32, which acts via the suction line 28 onto the dirt collection container 12 and the suction inlet 20. During suction flow operation of the vacuum device 10, the suction flow flows through the filter device 26. Under the effect of the suction flow, air laden with dirt particles enters the dirt collection container 12 via the suction inlet 20, and the particles can be collected in the dirt collection container 12. The filter device 26 filters out dirt particles. Accordingly, it has a dirty side 36, which faces the dirt collection container 12, and a clean side 38, to which the suction line 28 is connected.

[0057] (Cleaned) suction air can be released from the suction unit 30 to the environment via exhaust air openings.

[0058] In one embodiment, a cleaning device 40 is assigned to the filter device 26. The cleaning device 40 is arranged in the suction head 18 such that it can act upon the filter device 26 for a cleaning process. Solid particles accumulate on the filter of the filter device 26. Such solid particles can be removed via the cleaning device 40 in order to improve the filtering effect of the filter device 26.

[0059] In one embodiment, the cleaning device 40 is an external air valve device which applies air blasts to the filter device 26 in order to achieve a cleaning effect.

[0060] The filter device 26 can generally be removed from the filter holder 72 and thus from the suction device 10 in order to enable, for example, a filter replacement.

[0061] When the filter device 26 is inserted into the suction device 10, i.e., in the described embodiment, it is inserted into the suction head 18, and the suction head 18 is positioned on the dirt collection container 12 and, in particular, is locked thereto, the filter device 26 has a sealing function; the suction flow can only flow through the filter material of the filter of the filter device 26 from the dirt collection container 12 into the suction line 28.

[0062] At least one pressure sensor 42 of a pressure sensor device is arranged on the suction line 28 between the filter device 26 and the blower device 32. This pressure sensor 42 can measure the pressure in the suction flow downstream of the filter device 26. The prevailing pressure in the suction line 28 can be determined.

[0063] In one embodiment, the pressure sensor 42 is arranged such that it is not located in an area where the cleaning device 40 acts on the filter device 26. If, for example, the cleaning device 40 is an external air valve device, then the pressure sensor 42 is preferably arranged such that it is at least not directly acted upon by air blasts from the cleaning device 40.

[0064] The suction device 10 has a controller 44 that controls the operation of the suction device 10. This controller 44 comprises one or more circuit boards on which electronic elements are arranged. The controller 44 is positioned in particular in the suction head 18.

[0065] In principle, the suction device 10 can be operated without the filter device 26. However, this results in sucked-in solid particles being blown back into the environment. Furthermore, relatively large quantities of solid particles can enter the suction line 28 and the blower device 32 and cause damage. Operating the suction device 10 without the filter device 26 is particularly critical when working with hazardous dust.

[0066] According to the invention, it is provided that the suction device 10 automatically detects whether a filter device 26 is inserted or not, and if a missing filter device 26 is detected, (permanent) operation of the suction device 10 is prevented.

[0067] In one embodiment, the controller 44 comprises an evaluation unit 46 ( Figure 2 ). The evaluation unit 46 is particularly integrated into the controller 44.

[0068] In principle, it is also possible for the evaluation unit 46 to be spaced apart from the controller 44 and to cooperate with the controller 44 in terms of signal effectiveness.

[0069] Various data are provided to the evaluation unit 46. The evaluation unit 46 includes a corresponding (input) interface 48 for this purpose. A testing device 50 of the evaluation unit 46 checks for the presence or absence of the filter device 26 based on the available data.

[0070] For this purpose, the testing device 50 uses one or more algorithms or accesses a table stored in a storage device 52.

[0071] The evaluation unit 46 further comprises an (output) interface 54. This interface 54 directly or indirectly controls, in particular, the suction unit 30 and thereby the drive motor 34. For example, the interface 54 generates a corresponding shutdown signal, which is transmitted to a switch 56 (in particular to the controller 44) in order to be able to shut down the suction unit 30 upon detection of a missing filter device 26.

[0072] The pressure sensor 42 of the pressure sensor device provides its measured values ​​to the evaluation unit 46. Based on the measured pressure values, the evaluation unit 46 then checks for the presence or absence of the filter device 46.

[0073] The drive motor 34 is supplied with electrical energy via an electrical energy source 58. Voltage fluctuations can generally occur at the electrical energy source 58.

[0074] For a mains-operated vacuum cleaner 10, the primary electrical energy source 58 is, for example, a public power grid. Voltage fluctuations can occur in such a public power grid. It has been shown that such voltage fluctuations can generally have an impact.

[0075] In one embodiment, the evaluation unit 56 comprises a determination device 60 for this electrical voltage in order to be able to take into account any deviations from a nominal voltage (such as 230 V).

[0076] The determination device 60 determines the actual voltage acting, in particular for the drive motor 34.

[0077] It is also fundamentally possible for the electrical power consumption of the suction unit 30 to influence the test. In one embodiment, the evaluation unit 46 comprises a determination device 62 for a corresponding power consumption P. In particular, it is provided that the electrical power consumption is divided into specific ranges, and in particular into a minimum power consumption at which suction operation is still possible, and a maximum power consumption.

[0078] The maximum power consumption is the maximum power that the blower device 32 can draw with an open reference suction hose of a certain length and diameter.

[0079] To test whether the filter device 26 is present or not, the suction device 10 must be operated, i.e., the suction unit 30 must be switched on. In one embodiment, the evaluation unit 46 includes a timer 64. This timer 64 measures the time that has elapsed since the suction unit 30 was switched on. It has been shown that a certain time interval must be waited for before test results can be determined or test results can be used effectively to switch the suction unit 30 off again if necessary.

[0080] In particular, this specific time interval is predetermined. It is, for example, at least 2.5 s, preferably at least 3 s, and particularly preferably at least 3.5 s. In a specific embodiment, this specific time interval is 4 s or 5 s.

[0081] The method according to the invention for operating the vacuum cleaner 10 and for detecting whether the filter device 26 is present or not functions as follows: When the vacuum cleaner 10 is put into operation, the suction unit 30 is started up. A suction flow is generated, which, via the suction line 28, acts on the dirt collection container 12, the suction inlet 20, and a suction hose 22 connected thereto.

[0082] The test is performed, whereby the specified time interval is waited for before the test is performed or the test results are used, in particular, to shut down the suction unit 30 (if a missing filter device 26 is detected). The timer 64 checks whether this specified time interval has already expired or not.

[0083] The measured values ​​of the pressure sensor 42 are used for testing.

[0084] A check is performed to determine whether the pressure falls below a certain threshold. This pressure threshold can, in principle, be calculated using one or more algorithms, or it can be stored in a table, particularly in the memory device 52.

[0085] When the filter device 26 is inserted, a pressure is established in the suction line 28 at a specific hose diameter W of the suction hose 22, a predetermined voltage U, and a specific power consumption P, which is approximately constant and can be measured via the pressure sensor 42. This pressure is a negative pressure relative to the ambient pressure.

[0086] If the filter device 26 is not present, then a pressure value is also established which is different from the pressure value when the filter device 26 is present. Usually, the absolute pressure value is greater when the filter device 26 is not present than when the filter device 26 is present, since when the filter device 26 is missing, the sealing effect of the filter device 26 on the suction head 18 is missing and bypass channels for false air are therefore open.

[0087] In relation to absolute pressure values, it can then be detected that no filter device 26 is present by exceeding a predetermined threshold value as an absolute pressure value. If a negative pressure is determined as a differential pressure to the ambient pressure, which is too small (below a threshold value), then this is a detection result for a missing filter device 26, which leads to the shutdown of the suction unit 30.

[0088] In particular, threshold values ​​are then stored in the memory device 52 in tabular form in their dependence on U and P.

[0089] The threshold values ​​are previously determined for a specific suction device 10 and stored in the storage device 52 in a table or a corresponding algorithm is provided for this purpose.

[0090] In one embodiment, for a specific suction device 10, the pressure values ​​at the pressure sensor 42 were measured at a room temperature of 20°C to determine threshold values ​​for different voltages (230 V, 207 V, and 254 V) at different hose diameters W. In one case, the filter device 26 was used and in the other case, it was omitted.

[0091] Furthermore, the suction unit 30 was operated as described above with minimum power consumption P and maximum power consumption P. The following measured values ​​were obtained: Table 1: U = 230V: Hose diameter W [mm] Negative pressure [mbar] Max power P / With filter device Negative pressure [mbar] Max. power P / without filter device Negative pressure [mbar] min Power P / With filter device Negative pressure [mbar] min power P / without filter device 50 41 10 20 6 40 58 12 28 7 35 67 13 34 7,5 32 75 13,5 39 7,9 27 104 16 58 9,3 21 160 20,6 89 11,4 Table 2: U=207V: Hose diameter W [mm] Negative pressure [mbar] Max power P / With filter device Negative pressure [mbar] Max. power P / without filter device Negative pressure [mbar] min Power P / With filter device Negative pressure [mbar] min power P / without filter device 50 37 8,4 19,4 4,8 40 52 9,9 27 8 35 64 11,3 34 6,2 32 67 11,8 35 6,5 27 92 14,4 51 7,7 21 137 18,5 76 9,6 Table 3: U=254V : Hose diameter W [mm] Negative pressure [mbar] Max power P / With filter device Negative pressure [mbar] Max. power P / without filter device Negative pressure [mbar] min Power P / With filter device Negative pressure [mbar] min power P / without filter device 50 49 11,2 26,5 6,3 40 67 13,7 37 7,5 35 81 15,3 46 8,4 32 87 15,5 49 8,5 27 123 18,9 69 10,2 21 184 24 103 12,9

[0092] The negative pressure mentioned in the table is the pressure difference from the ambient pressure. The absolute pressure is therefore the difference between the ambient pressure and the negative pressure.

[0093] The different voltage values ​​characterize a nominal voltage (230 V), a large undervoltage, and a large overvoltage. Practical experience has shown that such a categorization is sufficient for mains-operated vacuum cleaners.

[0094] It can be seen from the tables that with the filter device 26 present, the negative pressure is greater than without the filter device 26. This means that with the filter device 26 present, the absolute pressure is lower than without the filter device 26.

[0095] These tables also show the dependence on the voltage U and the power consumption P.

[0096] Furthermore, one can see (as expected) that as the hose diameter decreases, the negative pressure increases, i.e. the absolute pressure decreases.

[0097] It is intended that the threshold values, which are stored in particular in tabular form in the storage device 52, are determined in such a way that the hose diameter W is not taken into account, so that they are, to a certain extent, universal for the suction device 10, regardless of the suction hose 22 used.

[0098] From the measured results, a corresponding threshold table is then generated by using threshold values ​​that apply to all hose diameters W: Table 4: U p T (Max. Power) p T (Min. Power) 207 27 14 230 30 15 254 36 19

[0099] The pressure p T is the corresponding threshold pressure, which is indicated as negative pressure in the table shown. As mentioned above, the corresponding threshold, when related to absolute pressure values, is the difference between the ambient pressure and p T .

[0100] The corresponding threshold values ​​are stored in a table for the maximum power consumption and the minimum power consumption. Furthermore, they are stored for the respective voltage U of the electrical energy source 58, with categorization also taking place here. (It is usually sufficient to divide the voltage U into a few ranges, such as three.)

[0101] Based on this threshold value table, the evaluation unit 46 then checks whether a shutdown signal should be generated for the suction unit 30 or not.

[0102] The following table shows, for different hose diameters, how long it takes between commissioning of the suction unit 30 for different hose diameters W with filter device 26 and without filter device 26 until stable pressure values ​​are established at the pressure sensor 42: Table 5: Time [s] Hose diameter W [mm] with filter device / open without filter device / open 21 2,75 0,83 27 2,05 1,48 32 2,35 1,31 35 2,37 1,03 40 2,03 1,11 51 1,06 1,13

[0103] From these measured values, the specific time interval can be determined, which is used to release test results or to perform the test, which can lead to a shutdown. It can be seen from the table that, for example, a waiting time of approximately 3 seconds is sufficient to achieve stable pressure conditions under all conditions (with filter device 26, without filter device 26, different hose diameters W). If, for example, a safety margin of 1 s or more is added here, then the specific time interval can be set to (at least) 4 s, from which a shutdown signal for the suction unit 30 can generally be generated.

[0104] Tables 1 to 3 and 5 are "calibration tables" used to define the necessary parameters (pressure thresholds, specific time intervals for meaningful testing) for the operation of the suction device 10. The values ​​of Table 4 are stored in the memory device 52. The duration for the specific time interval determined from the data in Table 5 is also stored in the evaluation unit 46 (and there, for example, in the memory device 52).

[0105] By measuring the pressure at the pressure sensor 42 above the filter device 26 and subsequently at the filter device 26 upstream of the blower device 32, it is possible to reliably determine whether the filter device 26 is inserted or not. This detection can be improved by taking into account the actual voltage of the electrical energy source 58 and, if applicable, the power consumption of the suction unit 30.

[0106] By waiting a certain time interval after commissioning of the suction unit 30 for the use of test results, it can be ensured that a "settling process" is completed immediately after commissioning of the suction unit 30.

[0107] It has been shown that a reliable test is achieved even when suction hoses 22 of different diameters are used. The test for the presence of the filter device 26 can thus be performed independently of the accessories.

[0108] The design effort for the suction device 10 is minimized for this test.

[0109] This prevents the suction device 10 from being operated for extended periods without the filter device 26. In principle, it can be ensured that the suction device 10 is operated without the filter device 26 for a maximum of the specified time interval (e.g., 4 seconds).

[0110] If a filter device 26 is detected, the detection results of the pressure sensor 42 can also be used for other measures (in Figure 2 indicated by the reference numeral 26). Such measures include, for example, a demand-based filter cleaning of the filter device 26 by appropriately controlling the cleaning device 40. For example, a gradual increase in pressure in the suction line 28 (increase in the absolute pressure, reduction in the negative pressure) can be interpreted as a gradual clogging of the filter device 26, and when a threshold is reached, filter cleaning can then be initiated by the cleaning device 40.

[0111] Furthermore, for example, a volume flow can be derived from the pressure measured values ​​and a maintenance signal can be generated if a threshold value for a volume flow is undershot.

[0112] According to the invention, a vacuum cleaner 10 is provided in which the presence of the filter device 26 can be detected with minimal design effort. This ensures that continued operation is not possible if the filter device 26 is detected as missing. This prevents dust from being blown into the environment by the vacuum cleaner 10. List of reference symbols

[0113] 10 Vacuum cleaner 12 Dirt collection container 14 Caster 16 Wheel assembly 18 Suction head 20 Suction inlet 22 Suction hose 24 Suction outlet 26 Filter assembly 27 Filter holder 28 Suction line 30 Suction unit 32 Blower assembly 34 Drive motor 36 Dirty side 38 Clean side 40 Cleaning device 42 Pressure sensor 44 Control unit 46 Evaluation unit 48 (Input) interface 50 Testing device 52 Storage device 54 (Output) interface 56 Switch 58 Electrical energy source 60 Voltage detection device 62 Determination device 64 Timer 66 "Measures"

Claims

1. Method for operating a suction device (10), said suction device (10) comprising a suction unit (30) and a removable filtering device (26), wherein the suction unit (30) generates a suction flow that flows through the filtering device (26) when this is arranged on the suction device (10), in which method, after the suction unit (30) is started up, a check is performed as to whether the filtering device (26) is present, and if it is detected that the filtering device (26) is not present, the suction unit (30) is switched off, wherein an evaluation unit (46) uses check data and determines therefrom whether a switch-off signal is to be generated for the suction unit (30) or not, characterized in that the evaluation unit (46) uses an algorithm or a table to arrive at a decision on switching off the suction unit (30) based on the check data, and in that the table contains at least one threshold value or the algorithm defines at least one threshold value, wherein the at least one threshold value is a threshold value for switching off the suction unit (30).

2. Method according to claim 1, characterized in that there is a delay of a defined time interval after the suction unit (30) is started up before check results for switching off or continuing to operate the suction unit (30) are used, and in particular characterized in that the defined time interval is at least 2.5 s, preferably at least 3 s and in particular at least 3.5 s.

3. Method according to any one of the preceding claims, characterized in that the check for the presence of the filtering device (26) is carried out on the suction flow.

4. Method according to any one of the preceding claims, characterized in that pressure values measured on the suction flow between the filtering device (26) and the suction unit (30) form the basis of the check, and in particular characterized by at least one of the following: - the pressure measured values are determined at one or more locations in relation to the suction flow above a holder (27) for the filtering device (26), wherein this location or these locations is / are above the filtering device (26) when the filtering device (26) is inserted in the filter holder (27); - the location or locations at which pressure measured values are determined lie outside a region in which a cleaning-off device (40) acts on the filtering device (26); - for the purpose of checking, furthermore an electrical voltage (U) of an energy source (56) is used for the suction unit (30).

5. Method according to any one of the preceding claims, characterized in that the evaluation unit (46) is connected to a controller (44) for the suction unit (30) in a manner allowing signalling, or is part of this controller (44).

6. Method according to any of the preceding claims, characterized in that the at least one threshold value is a pressure value, wherein switching off of the suction unit (30) is performed in the event of an absolute pressure value that is too high in relation to the threshold value, and in particular characterized in that the table includes threshold values at different electrical voltages (U) of an energy source (58) for the suction unit (30), or the algorithm defines threshold values at such different electrical voltages (U).

7. Method according to claim 6, characterized in that the table includes threshold values for different power consumptions (P) of the suction unit (30), or the algorithm defines such threshold values for different powers (P) of the suction unit (30), and in particular performs a classification into a minimum power consumption and maximum power consumption of the suction unit (30).

8. Method according to claim 6 or 7, wherein the threshold values are determined from measurements in which suction hoses (22) of different diameters (W) are attached to the suction device (10) and pressure measured values are measured with the filtering device (26) used and without using the filtering device (26), and in particular characterized in that, when the threshold values are determined, different electrical voltages (U) of an energy source (58) for the suction unit (30) are used, and in particular characterized in that, when the threshold values are determined, different power consumptions (P) are used for the suction unit (30), and in particular a minimum power consumption and a maximum power consumption are used.

9. Method according to any one of the preceding claims, characterized in that using a filtering device (26) has the function of providing sealing at a transition to a dirt collecting container (12).

10. Method according to any one of the preceding claims, characterized in that the evaluation unit (46) initiates measures based on the determined check data if the presence of a filtering device (26) is detected, wherein these measures may include at least one of: - initiation of cleaning off the filtering device (26) by a cleaning-off device (40); and / or - generation of a maintenance signal when a flow rate falls below a threshold value.

11. Suction device, comprising a suction unit (30) and a removable filtering device (26), wherein the suction unit (30) generates a suction flow that flows through the filtering device (26) when the filtering device (26) is arranged on the suction device (30), a pressure sensor device (42) that is arranged between the filtering device (26) and the suction unit (30) and provides pressure measured values of the suction flow downstream of the filtering device (26) and upstream of the suction unit (30), and an evaluation unit (46) that, after the suction unit (30) is started up, determines on the basis of the measurement data of the pressure sensor device (42) whether the filtering device is being used or not and, if it is detected that there is no filtering device (26), generates a switch-off signal for the suction unit (30), characterized in that the evaluation unit (46) includes a storage device (52) that stores threshold values or data for an algorithm for threshold values, wherein the threshold values are threshold values for switching off the suction unit (30).

12. Suction device according to claim 11, characterized in that the evaluation unit (46) includes a timing element (64) that ensures that a switch-off signal only becomes effective once a defined time interval after starting up the suction unit (30) has elapsed.

13. Suction device according to claim 11 or 12, characterized in that the threshold values are pressure values.

14. Suction device according to any one of claims 11 to 13, <b>characterized by at least one of the following: - the evaluation unit (46) includes a device (60) for determining an electrical voltage (U) of an electrical energy source (58) for the suction unit (30); - the evaluation unit (46) includes a device (62) for defining a power consumption of the suction unit (30), and in particular classifies the power consumption (P) into a maximum power consumption or a minimum power consumption; - the evaluation unit (46) is connected to a controller (44) of the suction device (10) in a manner allowing signalling, or is part of this controller (44).

15. Use of the suction device according to any one of claims 11 to 14 for carrying out the method according to any one of claims 1 to 10, or use of the method according to any one of claims 1 to 10 using the suction device according to any one of claims 11 to 14.