JP2018531689A - Cleaning device, especially home vacuum cleaner - Google Patents

Abstract

The present invention relates to a cleaning device (1) comprising a fan (2) and a pressure sensor (3) for determining a negative pressure generated by the fan (2), and more particularly to a household vacuum cleaner. In order to obtain a cleaning device (1) that achieves the best possible cleaning result with as little flow resistance as possible in the attachment (7), the pressure sensor (3) is an absolute pressure sensor. The present invention also relates to a method of operating the cleaning device (1) in which the suction force of the cleaning device (1) changes according to the determined flow resistance of the attachment (7) of the cleaning device (1).

Description

  The present invention relates to a cleaning device having a fan and a pressure sensor for determining a negative pressure generated by the fan, and more particularly to a household vacuum cleaner.

  Furthermore, the present invention relates to a method for operating such a cleaning device.

  Cleaning devices of the type described above are known in the prior art. Furthermore, they can have a device for changing the fan output of the fan in order to remove as much as possible the suction material from the surface to be cleaned. Again, since it is known to vary the fan output in response to the flow resistance of the attachment of the cleaning device, moving the cleaning device on the surface to be cleaned to achieve the best possible cleaning result Requires the lowest possible sliding force. The sliding force applied here depends inter alia on the floor covering, for example a hard floor or a carpeted floor.

  A differential pressure sensor is used in the prior art to measure the negative pressure generated by the fan. Here, what is inconvenient is that the absolute pressure contributing to the flow resistance of the attachment is not considered. This adversely affects the cleaning result.

  Accordingly, it is an object of the present invention to provide a cleaning device that achieves the best possible cleaning result with the smallest possible flow resistance of the attachment.

  In order to achieve the above-described object, the present invention proposes a cleaning device in which the pressure sensor is an absolute pressure sensor.

  According to the present invention, the pressure sensor measures the current absolute pressure, but the absolute pressure can vary depending on where the cleaning device is used above sea level and weather conditions. As a result, absolute pressure fluctuations are taken into account and are not misinterpreted as pressure differences generated by the fan.

  Advantageously, the absolute pressure sensor has a detection area assigned to the suction area of the fan arranged in the connection area for the attachment, i.e. the area exposed to the suction force of the fan. This suction area in the cleaning device is usually located where the attachment is connected to the cleaning device. In this detection area, the absolute pressure sensor, on the one hand, measures the ambient pressure during the first measurement when the fan stops, ie without exposing the detection area to the suction air flow generated by the fan. On the other hand, the absolute pressure is measured during the second measurement when the fan is activated. The pressure difference calculated from these two absolute pressures is adjusted for the current ambient temperature. So the cleaning result is optimal regardless of the current ambient temperature.

  In a particularly simple embodiment, the detection area of the absolute pressure sensor is assigned to the suction area by placing the absolute pressure sensor directly in the suction area of the connection area.

  However, as an alternative, the pressure sensor is arranged in the area of the fan, in particular on a circuit board which is arranged in the blowing area of the fan, and a measurement channel is formed between the pressure sensor and the detection area. It can be proposed that the first end region of the measurement channel is arranged in the pressure sensor and the second end region of the measurement channel is in the suction region. In this embodiment, the position of the detection region and the position of the pressure sensor are different. As a result, the pressure sensor in the fan blowing area can be cooled by the fan blowing air. Here, the absolute pressure in the suction area is measured via the measurement channel. To achieve this purpose, the measurement channel has first and second end regions, the first end region being led to a pressure sensor, in particular so that the pressure sensor protrudes into the measurement channel. The second end region projects into the suction region, particularly in the flow path of the suction air flow generated by the fan from the attachment to the fan.

  It is proposed that the measurement channel is a hose part. The first end region of the hose portion can be glued to the circuit board or can be otherwise connected to the circuit board. Particularly advantageously, the open end of the measurement channel is covered by a part of the circuit board, which is connected as tightly as possible to the circuit board. The hose part is specifically designed as a flexible hose part and is guided into the suction area. There, the second end region is also advantageously hermetically connected to the suction channel of the connection region. However, as an alternative to designing the measurement channel as a hose part, a region of the housing of the cleaning device can be designed as a measurement channel. For example, the measuring channel may advantageously be formed in the housing of the cleaning device in an injection molding process. At the same time, this also makes it possible to form a receptacle for a circuit board with a pressure sensor, so that the first end region of the measurement channel contacts the circuit board when the circuit board is placed in the receptacle. be able to.

  Furthermore, the present invention proposes that a temperature sensor is arranged in the connection area. The temperature sensor is used to measure the current temperature in the connection area, and that temperature can be used to calculate the current air density. The air density is then used to calculate the fan volume flow. Volume flow is combined with the negative pressure generated by the fan to allow the attachment's current flow resistance to be determined. Thus, taking into account the current temperature in the suction area allows a more reliable determination of flow resistance.

  In addition, the evaluation and control device is designed such that the cleaning device adjusts the suction force resulting from the cleaning device in response to the negative pressure determined by the pressure sensor, the current fan output, and the current speed of the fan. It is proposed to have The negative pressure determined from the absolute pressure and the corresponding volume flow of the fan that can be derived from the fan characteristics of the fan determines the flow resistance of the attachment and thus also the sliding force applied to move the attachment. To do. This flow resistance is used by the evaluation and control device to adjust the suction force of the resulting cleaning device so as to keep the flow resistance as low as possible on the one hand and achieve the best possible cleaning result on the other hand. . The evaluation and control device can in particular be set up to control a constant suction force. The volume flow through the fan depends inter alia on the current fan output, which can be determined from the fan current and voltage. The fan current and voltage are measured, for example, by corresponding devices on the fan circuit board. Also, the fan speed is measured by a tachometer in the usual way. As a result, the evaluation and control device can use the measurement data described above and the known characteristic curve of the fan to determine the flow resistance, which helps to adjust the suction power of the cleaning device.

  Furthermore, it is provided that the evaluation and control device is designed to further adjust the suction force as a function of the temperature measured by the temperature sensor. This adjusts the evaluation for temperature dependent air density and contributes to optimal control of the fan suction. This is especially because the air density, and thus also the negative pressure generated by the fan, varies with temperature.

Apart from the cleaning device described above, the present invention also proposes a method of operating the cleaning device in which the suction force of the cleaning device varies according to the determined flow resistance of the attachment of the cleaning device. This way of working is
Measuring the absolute pressure in the suction area of the fan when it stops,
Measuring the absolute pressure in the suction area of the fan when the fan is activated;
Determining the negative pressure generated by the fan from the difference between the measured absolute pressures;
Determining the output of the fan;
Measuring the speed of the fan;
Determining the flow resistance of the attachment from negative pressure, fan output and speed by comparing with known fan characteristics of the fan;
Adjusting the suction force of the cleaning device by changing the speed of the fan and / or the output of the fan in response to the determined flow resistance;
Is provided.

  In the method according to the present invention, the first absolute pressure measurement is performed before the fan is operated, and the second absolute pressure measurement is performed after the fan is operated. Since the measurement of the first absolute pressure is performed in a very short time, for example, 300 milliseconds, the user of the cleaning device does not feel a delay in switching the operation of the fan. After the fan is activated, the absolute pressure can be measured, for example, at intervals of 10 to 20 times per second, preferably periodically. The negative pressure generated by the fan is determined from the absolute pressure determined when the fan is operating and the initial absolute pressure measured when the fan stops. Furthermore, the power consumed by the fan is determined. This is done periodically by measuring the current and voltage required by the fan. In addition, the fan speed is measured. All measured values, i.e., negative pressure, fan output, and fan speed, are included in determining the flow resistance of the attachment. In practice, the user notices the flow resistance of the attachment as a sliding force applied to move the cleaning device or attachment on the surface to be cleaned. With very high flow resistance, the user can only guide the cleaning device or attachment on the surface to be cleaned by applying a large level of force. This is accompanied by a low volume flow through the fan and thus a low suction force. The measured data is then compared to the known fan characteristics of the fan. From the known fan characteristics, the volumetric flow rates resulting from the respective flow resistances and pressure differences can be derived. If one of the known fan characteristics matches or most closely resembles the measured data, the currently measured suction force is adjusted to produce the best possible cleaning result. To adjust the suction force, the fan speed and / or fan output can be varied. Preferably, the suction force is adjusted to a constant amount.

  It is also proposed that the fan output cannot be increased further when the specified maximum flow resistance of the attachment is reached. As a result, maximum power consumption is provided in consideration of adjusting the flow resistance. In order to increase the volumetric flow rate, the fan output cannot be increased beyond the corresponding maximum flow resistance. The maximum flow resistance allowed, and thus the sliding force applied to move the attachment, can be given at 20N. This serves to protect the fan against overload.

  Furthermore, it is proposed that the flow resistance of the currently used attachment is also determined according to the temperature currently measured in the connection area. As already explained with respect to the cleaning device, the inclusion of the currently measured temperature makes it possible to achieve optimal cleaning results with the lowest possible flow resistance.

  Finally, it is proposed that the filling level of the filter arranged in the suction area of the fan is determined by comparing the determined flow resistance of the attachment with the reference value assigned to each specific filling level of the filter Is done. In order to infer the filling level from the flow resistance, characteristic lines or characteristic values based on experiments, each assigned to a specific filling level of the filter, are stored for the various operating modes. Also preferably, the suction force is kept constant regardless of the currently determined fill level of the filter.

  Finally, the user can operate the cleaning device via a selection means, for example a slide switch. For example, the first position of the slide switch is assigned to the automatic operation of the cleaning device. In this position, the evaluation and control device automatically adjusts the required fan output in view of the determined negative pressure to achieve a specific suction force or a specific volume flow. Further, an output level with a constant fan output can be provided, for example an output level with a constant fan output of 50 W and another output level with a higher fan output of 300 W. In addition, other power levels can be provided as maximum power levels. At this maximum power level, the fan output can be controlled in response to a detected floor covering, eg a hard floor or a carpeted floor. For example, it can be controlled to 700 W for cleaning a carpeted floor and 450 W for cleaning a hard floor. Here, this can include pure control. In other words, only the above-mentioned constant fan output is provided. No adjustment is made by flow resistance. However, instead, it is also possible to provide a dependence on the flow resistance (sliding force) that occurs in this mode of operation in addition to the dependence on the respective floor covering.

  The invention is described in more detail below on the basis of exemplary embodiments.

It is a perspective view of the external appearance of the cleaning apparatus which has an attachment. It is a longitudinal cross-sectional view of a cleaning apparatus and an attachment.

  FIG. 1 shows a cleaning device 1 designed here as a household upright vacuum cleaner. The cleaning device 1 has a base device 15 including a fan 2 and a filter chamber having a filter 14. An attachment 7 is connected to the connection region 5 of the base device 15. Attachment 7 is useful for treating surfaces such as hard floors and carpeted floors. When the fan 2 is activated, the suction material is guided to the filter 14 through the attachment 7.

  A guide rod 19 for handling the cleaning device 1 is disposed in the base device 15. The guide rod 19 has a hand grip element 20 at its end. The hand grip element 20 has an operating element 16 that allows the user to select various operating modes of the cleaning device 1. The operation element 16 includes a slide switch 17 and a button 18. Specifically, the slide switch 17 allows for four different positions to which four different operating modes are assigned.

  In the first position of the slide switch 17, the automatic mode of the cleaning device 1 can be set. In this mode of operation, the cleaning device 1 automatically adjusts the output of the fan 2 in response to the negative pressure generated by the fan 2 in order to achieve a specific suction force, ie a specific volume flow through the attachment 7. . In this mode of operation, the maximum value of the required fan output is provided to protect the fan 2 against overload. The output of the fan 2 cannot be increased beyond this maximum value. For example, the maximum value of the fan output can be designed such that the maximum flow resistance of the attachment 7 is 20N. This flow resistance corresponds to the maximum sliding force that must be spent to guide the attachment 7 on the surface to be cleaned. The interrelationship between the negative pressure generated by the fan 2, the volume flow through the attachment 7, and the sliding force or flow resistance of the attachment 7 can be derived from the characteristic curve of the fan 2 for the attachment 7 currently in use. it can.

  In addition to the automatic mode, the slide switch 17 is also used to set two operating modes that use a constant output of the fan 2. The output of the fan 2 can be, for example, 50 W in one operation mode and 300 W in another operation mode.

  Finally, the slide switch 17 can also be used to select the operating mode associated with the maximum power level of the fan 2 depending on the floor type. In this operation mode, the fan output is automatically set according to the type of surface to be cleaned. For example, a constant fan output of 700 W is set for a carpeted floor and a constant fan output of 450 W for a hard floor. Here, for example, depending on the sliding force generated by the attachment 7, that is, the flow resistance, automatic adjustment of the output of these fans is not provided.

  In addition, the operating element 16 has a button 18 that can be used for manual changes during the adjustment from the operating mode “maximum output depending on the type of floor” to a hard floor and a carpeted floor. For example, actuating button 18 can force attachment 7 settings for a hard floor to be cleaned, which are typically used only for carpeted floors.

  FIG. 2 shows a longitudinal section of the cleaning device 1. The base device 15 has a fan chamber 2 and a filter chamber having a filter 14. An attachment 7 is disposed in the connection region 5 of the base device 15. The air sucked by the fan 2 reaches the fan 2 through the attachment 7 and the filter 14, and then reaches the environment. The connection area 5 has a suction area 6 in which air reaching the base device 15 through the attachment 7 is sucked into the filter 14. A temperature sensor 13 is disposed in the suction region 6. A circuit board 9 that can be cooled by the blown air of the fan 2 is disposed in the blowout area 8 of the fan 2, that is, in the direction in which the suction air behind the fan 2 flows. The circuit board 9 is provided with a pressure sensor 3 which is an absolute pressure sensor. The pressure sensor 3 is further coupled to the measurement channel 10, the first end region 11 surrounds the pressure sensor 3 on the circuit board 9, and the second end region 12 exceeds the fan 2 and the filter 14 and the suction region 6. Protrusively. The second end region 12 determines the detection region 4 of the pressure sensor 3. The pressure sensor 3 disposed in the blowing area 8 of the fan 2 can measure the pressure in the suction area 6 formed upstream of the filter 14 using the measurement channel 10.

  Furthermore, the cleaning device 1 has an evaluation and control device (preferably also arranged on the circuit board 9) that serves to adjust the suction force of the cleaning device 1. As will be explained below, this adjustment is made according to the pressure sensor 3, possibly the measured value of the temperature sensor 13, the recorded power of the fan 2 and the speed of the fan 2.

  The invention will be described with respect to the operation mode “automatic”. In order to set the automatic mode, the slide switch 17 of the operating element 16 is brought to the corresponding position.

  The first absolute pressure measurement is started by the pressure sensor 3 by moving the slide switch 17 to the “automatic” position. This pressure measurement occurs when the fan 2 stops. If the cleaning device 1 has been operating in a different mode of operation up to this time, the fan 2 is initially turned off if necessary.

  Since the initial absolute pressure measurement only requires a short time, for example 300 milliseconds, the user of the cleaning device 1 cannot notice any delay until the time the fan 2 is activated. After this initial absolute pressure measurement is over, the fan 2 is automatically activated by the evaluation and control device of the cleaning device 1. Subsequently, the absolute pressure formed in the suction area 6 is determined during operation. This measurement when the fan 2 is activated is advantageously repeated, for example 10 to 20 times per second. Then, the difference between the absolute pressure measured when the fan 2 is activated and the absolute pressure first measured when the fan 2 is stopped is determined, and the negative pressure generated by the fan 2 is known.

  Furthermore, the current and voltage are measured in the usual way on the electric supply line of the fan 2 to determine the power consumed by the fan 2. A tachometer measures the speed of the fan 2. Then, the volume flow through the fan 2 is determined from the determined fan output of the fan 2, the speed of the fan 2, the absolute pressure measured when the fan 2 is stopped, and optionally the temperature measured by the temperature sensor 13. Is done. Based on this volumetric flow rate and the negative pressure generated by the fan 2, the flow resistance of the attachment 7 can be determined by comparing the measured data with a known characteristic curve of the fan 2. The determined flow resistance corresponds to the sliding force applied by the user of the cleaning device 1 to press the attachment 7 onto the surface to be cleaned. This flow resistance or this sliding force is used to adjust the suction force of the cleaning device 1, which is adjusted by changing the speed and / or the fan output. Preferably, the suction force is adjusted to a constant value. This also occurs regardless of the fill level of the filter 14. The described method involves true control of the suction force, not just control.

  For example, the flow resistance determined during operation of the cleaning device 1 exceeds a prescribed maximum value because the attachment 7 is sucked firmly onto the surface to be cleaned or the filter 14 is completely filled. If the situation occurs, the fan output will not increase further to avoid overloading the fan 2. The defined maximum flow resistance or the corresponding maximum slip force can be set to 20 N, for example.

  To further determine the fill level of the filter 14, the determined flow resistance of the attachment 7 can be compared to a reference value that is characteristic for each specific fill level of the filter 14. For example, characteristic lines or characteristic curves determined experimentally for different filling levels of the filter 14 are also used for evaluation with respect to the various operating modes or power levels of the fan 2, if necessary.

DESCRIPTION OF SYMBOLS 1 ... Cleaning apparatus 2 ... Fan 3 ... Pressure sensor 4 ... Detection area 5 ... Connection area 6 ... Suction area 7 ... Attachment 8 ... Outlet area 9 ... Circuit board 10 ... Measurement channel 11 ... 1st edge area 12 ... 2nd End region 13 ... temperature sensor 14 ... filter 15 ... base device 16 ... operating element 17 ... slide switch 18 ... button 19 ... guide rod 20 ... hand grip element

The present invention, fans and, have a pressure sensor for determining the negative pressure generated by the fan, the cleaning device is a pressure sensor is an absolute pressure sensor, in particular to domestic vacuum cleaners.

  Furthermore, the present invention relates to a method for operating such a cleaning device.

  Cleaning devices of the type described above are known in the prior art. Furthermore, they can have a device for changing the fan output of the fan in order to remove as much as possible the suction material from the surface to be cleaned. Again, since it is known to vary the fan output in response to the flow resistance of the attachment of the cleaning device, moving the cleaning device on the surface to be cleaned to achieve the best possible cleaning result Requires the lowest possible sliding force. The sliding force applied here depends inter alia on the floor covering, for example a hard floor or a carpeted floor.

  A differential pressure sensor is used in the prior art to measure the negative pressure generated by the fan. Here, what is inconvenient is that the absolute pressure contributing to the flow resistance of the attachment is not considered. This adversely affects the cleaning result.

A cleaning device is known from US Pat. No. 6,057,836 in which the filter cleaning process can be started in accordance with the measured differential pressure. Here again, an absolute pressure sensor can be provided for the pressure sensor.

Also, a cleaning device is known from US Pat. No. 6,053,077, in which the filter cleaning process can be started by measuring the differential pressure across the filter.

German Utility Model No. 20 2012 003 280 U1 US Patent Publication No. 2008/02018898 A1

Based on the prior art described above, the present invention relates to showing a cleaning device in which the pressure loss can be determined as advantageously as possible. With regard to the device, this object is achieved with the subject matter of claim 1. Its purpose is to provide an evaluation and control device designed to adjust the resulting suction force of the cleaning device according to the negative pressure determined by the pressure sensor, the current fan output, and the current speed of the fan It is to be. The negative pressure determined from the absolute pressure and the corresponding volume flow of the fan that can be derived from the fan characteristics of the fan determines the flow resistance of the attachment and thus also the sliding force applied to move the attachment. To do. This flow resistance is used by the evaluation and control device to adjust the suction force of the resulting cleaning device so as to keep the flow resistance as low as possible on the one hand and achieve the best possible cleaning result on the other hand. . The evaluation and control device can in particular be set up to control a constant suction force. The volume flow through the fan depends inter alia on the current fan output, which can be determined from the fan current and voltage. The fan current and voltage are measured, for example, by corresponding devices on the fan circuit board. Also, the fan speed is measured by a tachometer in the usual way. As a result, the evaluation and control device can use the measurement data described above and the known characteristic curve of the fan to determine the flow resistance, which helps to adjust the suction power of the cleaning device.

  Advantageously, the absolute pressure sensor has a detection area assigned to the suction area of the fan arranged in the connection area for the attachment, i.e. the area exposed to the suction force of the fan. This suction area in the cleaning device is usually located where the attachment is connected to the cleaning device. In this detection area, the absolute pressure sensor, on the one hand, measures the ambient pressure during the first measurement when the fan stops, ie without exposing the detection area to the suction air flow generated by the fan. On the other hand, the absolute pressure is measured during the second measurement when the fan is activated. The pressure difference calculated from these two absolute pressures is adjusted for the current ambient temperature. So the cleaning result is optimal regardless of the current ambient temperature.

  In a particularly simple embodiment, the detection area of the absolute pressure sensor is assigned to the suction area by placing the absolute pressure sensor directly in the suction area of the connection area.

  However, as an alternative, the pressure sensor is arranged in the area of the fan, in particular on a circuit board which is arranged in the blowing area of the fan, and a measurement channel is formed between the pressure sensor and the detection area. It can be proposed that the first end region of the measurement channel is arranged in the pressure sensor and the second end region of the measurement channel is in the suction region. In this embodiment, the position of the detection region and the position of the pressure sensor are different. As a result, the pressure sensor in the fan blowing area can be cooled by the fan blowing air. Here, the absolute pressure in the suction area is measured via the measurement channel. To achieve this purpose, the measurement channel has first and second end regions, the first end region being led to a pressure sensor, in particular so that the pressure sensor protrudes into the measurement channel. The second end region projects into the suction region, particularly in the flow path of the suction air flow generated by the fan from the attachment to the fan.

  It is proposed that the measurement channel is a hose part. The first end region of the hose portion can be glued to the circuit board or can be otherwise connected to the circuit board. Particularly advantageously, the open end of the measurement channel is covered by a part of the circuit board, which is connected as tightly as possible to the circuit board. The hose part is specifically designed as a flexible hose part and is guided into the suction area. There, the second end region is also advantageously hermetically connected to the suction channel of the connection region. However, as an alternative to designing the measurement channel as a hose part, a region of the housing of the cleaning device can be designed as a measurement channel. For example, the measuring channel may advantageously be formed in the housing of the cleaning device in an injection molding process. At the same time, this also makes it possible to form a receptacle for a circuit board with a pressure sensor, so that the first end region of the measurement channel contacts the circuit board when the circuit board is placed in the receptacle. be able to.

  Furthermore, the present invention proposes that a temperature sensor is arranged in the connection area. The temperature sensor is used to measure the current temperature in the connection area, and that temperature can be used to calculate the current air density. The air density is then used to calculate the fan volume flow. Volume flow is combined with the negative pressure generated by the fan to allow the attachment's current flow resistance to be determined. Thus, taking into account the current temperature in the suction area allows a more reliable determination of flow resistance.

  Furthermore, it is provided that the evaluation and control device is designed to further adjust the suction force as a function of the temperature measured by the temperature sensor. This adjusts the evaluation for temperature dependent air density and contributes to optimal control of the fan suction. This is especially because the air density, and thus also the negative pressure generated by the fan, varies with temperature.

Apart from the cleaning device described above, the present invention also proposes a method of operating the cleaning device in which the suction force of the cleaning device varies according to the determined flow resistance of the attachment of the cleaning device. This way of working is
Measuring the absolute pressure in the suction area of the fan when it stops,
Measuring the absolute pressure in the suction area of the fan when the fan is activated;
Determining the negative pressure generated by the fan from the difference between the measured absolute pressures;
Determining the output of the fan;
Measuring the speed of the fan;
Determining the flow resistance of the attachment from negative pressure, fan output and speed by comparing with known fan characteristics of the fan;
Adjusting the suction force of the cleaning device by changing the speed of the fan and / or the output of the fan in response to the determined flow resistance;
Is provided.

  In the method according to the present invention, the first absolute pressure measurement is performed before the fan is operated, and the second absolute pressure measurement is performed after the fan is operated. Since the measurement of the first absolute pressure is performed in a very short time, for example, 300 milliseconds, the user of the cleaning device does not feel a delay in switching the operation of the fan. After the fan is activated, the absolute pressure can be measured, for example, at intervals of 10 to 20 times per second, preferably periodically. The negative pressure generated by the fan is determined from the absolute pressure determined when the fan is operating and the initial absolute pressure measured when the fan stops. Furthermore, the power consumed by the fan is determined. This is done periodically by measuring the current and voltage required by the fan. In addition, the fan speed is measured. All measured values, i.e., negative pressure, fan output, and fan speed, are included in determining the flow resistance of the attachment. In practice, the user notices the flow resistance of the attachment as a sliding force applied to move the cleaning device or attachment on the surface to be cleaned. With very high flow resistance, the user can only guide the cleaning device or attachment on the surface to be cleaned by applying a large level of force. This is accompanied by a low volume flow through the fan and thus a low suction force. The measured data is then compared to the known fan characteristics of the fan. From the known fan characteristics, the volumetric flow rates resulting from the respective flow resistances and pressure differences can be derived. If one of the known fan characteristics matches or most closely resembles the measured data, the currently measured suction force is adjusted to produce the best possible cleaning result. To adjust the suction force, the fan speed and / or fan output can be varied. Preferably, the suction force is adjusted to a constant amount.

  It is also proposed that the fan output cannot be increased further when the specified maximum flow resistance of the attachment is reached. As a result, maximum power consumption is provided in consideration of adjusting the flow resistance. In order to increase the volumetric flow rate, the fan output cannot be increased beyond the corresponding maximum flow resistance. The maximum flow resistance allowed, and thus the sliding force applied to move the attachment, can be given at 20N. This serves to protect the fan against overload.

  Furthermore, it is proposed that the flow resistance of the currently used attachment is also determined according to the temperature currently measured in the connection area. As already explained with respect to the cleaning device, the inclusion of the currently measured temperature makes it possible to achieve optimal cleaning results with the lowest possible flow resistance.

  Finally, it is proposed that the filling level of the filter arranged in the suction area of the fan is determined by comparing the determined flow resistance of the attachment with the reference value assigned to each specific filling level of the filter Is done. In order to infer the filling level from the flow resistance, characteristic lines or characteristic values based on experiments, each assigned to a specific filling level of the filter, are stored for the various operating modes. Also preferably, the suction force is kept constant regardless of the currently determined fill level of the filter.

  Finally, the user can operate the cleaning device via a selection means, for example a slide switch. For example, the first position of the slide switch is assigned to the automatic operation of the cleaning device. In this position, the evaluation and control device automatically adjusts the required fan output in view of the determined negative pressure to achieve a specific suction force or a specific volume flow. Further, an output level with a constant fan output can be provided, for example an output level with a constant fan output of 50 W and another output level with a higher fan output of 300 W. In addition, other power levels can be provided as maximum power levels. At this maximum power level, the fan output can be controlled in response to a detected floor covering, eg a hard floor or a carpeted floor. For example, it can be controlled to 700 W for cleaning a carpeted floor and 450 W for cleaning a hard floor. Here, this can include pure control. In other words, only the above-mentioned constant fan output is provided. No adjustment is made by flow resistance. However, instead, it is also possible to provide a dependence on the flow resistance (sliding force) that occurs in this mode of operation in addition to the dependence on the respective floor covering.

  The invention is described in more detail below on the basis of exemplary embodiments.

It is a perspective view of the external appearance of the cleaning apparatus which has an attachment. It is a longitudinal cross-sectional view of a cleaning apparatus and an attachment.

  FIG. 1 shows a cleaning device 1 designed here as a household upright vacuum cleaner. The cleaning device 1 has a base device 15 including a fan 2 and a filter chamber having a filter 14. An attachment 7 is connected to the connection region 5 of the base device 15. Attachment 7 is useful for treating surfaces such as hard floors and carpeted floors. When the fan 2 is activated, the suction material is guided to the filter 14 through the attachment 7.

  A guide rod 19 for handling the cleaning device 1 is disposed in the base device 15. The guide rod 19 has a hand grip element 20 at its end. The hand grip element 20 has an operating element 16 that allows the user to select various operating modes of the cleaning device 1. The operation element 16 includes a slide switch 17 and a button 18. Specifically, the slide switch 17 allows for four different positions to which four different operating modes are assigned.

  In the first position of the slide switch 17, the automatic mode of the cleaning device 1 can be set. In this mode of operation, the cleaning device 1 automatically adjusts the output of the fan 2 in response to the negative pressure generated by the fan 2 in order to achieve a specific suction force, ie a specific volume flow through the attachment 7. . In this mode of operation, the maximum value of the required fan output is provided to protect the fan 2 against overload. The output of the fan 2 cannot be increased beyond this maximum value. For example, the maximum value of the fan output can be designed such that the maximum flow resistance of the attachment 7 is 20N. This flow resistance corresponds to the maximum sliding force that must be spent to guide the attachment 7 on the surface to be cleaned. The interrelationship between the negative pressure generated by the fan 2, the volume flow through the attachment 7, and the sliding force or flow resistance of the attachment 7 can be derived from the characteristic curve of the fan 2 for the attachment 7 currently in use. it can.

  In addition to the automatic mode, the slide switch 17 is also used to set two operating modes that use a constant output of the fan 2. The output of the fan 2 can be, for example, 50 W in one operation mode and 300 W in another operation mode.

  Finally, the slide switch 17 can also be used to select the operating mode associated with the maximum power level of the fan 2 depending on the floor type. In this operation mode, the fan output is automatically set according to the type of surface to be cleaned. For example, a constant fan output of 700 W is set for a carpeted floor and a constant fan output of 450 W for a hard floor. Here, for example, depending on the sliding force generated by the attachment 7, that is, the flow resistance, automatic adjustment of the output of these fans is not provided.

  In addition, the operating element 16 has a button 18 that can be used for manual changes during the adjustment from the operating mode “maximum output depending on the type of floor” to a hard floor and a carpeted floor. For example, actuating button 18 can force attachment 7 settings for a hard floor to be cleaned, which are typically used only for carpeted floors.

  FIG. 2 shows a longitudinal section of the cleaning device 1. The base device 15 has a fan chamber 2 and a filter chamber having a filter 14. An attachment 7 is disposed in the connection region 5 of the base device 15. The air sucked by the fan 2 reaches the fan 2 through the attachment 7 and the filter 14, and then reaches the environment. The connection area 5 has a suction area 6 in which air reaching the base device 15 through the attachment 7 is sucked into the filter 14. A temperature sensor 13 is disposed in the suction region 6. A circuit board 9 that can be cooled by the blown air of the fan 2 is disposed in the blowout area 8 of the fan 2, that is, in the direction in which the suction air behind the fan 2 flows. The circuit board 9 is provided with a pressure sensor 3 which is an absolute pressure sensor. The pressure sensor 3 is further coupled to the measurement channel 10, the first end region 11 surrounds the pressure sensor 3 on the circuit board 9, and the second end region 12 exceeds the fan 2 and the filter 14 and the suction region 6. Protrusively. The second end region 12 determines the detection region 4 of the pressure sensor 3. The pressure sensor 3 disposed in the blowing area 8 of the fan 2 can measure the pressure in the suction area 6 formed upstream of the filter 14 using the measurement channel 10.

  Furthermore, the cleaning device 1 has an evaluation and control device (preferably also arranged on the circuit board 9) that serves to adjust the suction force of the cleaning device 1. As will be explained below, this adjustment is made according to the pressure sensor 3, possibly the measured value of the temperature sensor 13, the recorded power of the fan 2 and the speed of the fan 2.

  The invention will be described with respect to the operation mode “automatic”. In order to set the automatic mode, the slide switch 17 of the operating element 16 is brought to the corresponding position.

  The first absolute pressure measurement is started by the pressure sensor 3 by moving the slide switch 17 to the “automatic” position. This pressure measurement occurs when the fan 2 stops. If the cleaning device 1 has been operating in a different mode of operation up to this time, the fan 2 is initially turned off if necessary.

  Since the initial absolute pressure measurement only requires a short time, for example 300 milliseconds, the user of the cleaning device 1 cannot notice any delay until the time the fan 2 is activated. After this initial absolute pressure measurement is over, the fan 2 is automatically activated by the evaluation and control device of the cleaning device 1. Subsequently, the absolute pressure formed in the suction area 6 is determined during operation. This measurement when the fan 2 is activated is advantageously repeated, for example 10 to 20 times per second. Then, the difference between the absolute pressure measured when the fan 2 is activated and the absolute pressure first measured when the fan 2 is stopped is determined, and the negative pressure generated by the fan 2 is known.

  Furthermore, the current and voltage are measured in the usual way on the electric supply line of the fan 2 to determine the power consumed by the fan 2. A tachometer measures the speed of the fan 2. Then, the volume flow through the fan 2 is determined from the determined fan output of the fan 2, the speed of the fan 2, the absolute pressure measured when the fan 2 is stopped, and optionally the temperature measured by the temperature sensor 13. Is done. Based on this volumetric flow rate and the negative pressure generated by the fan 2, the flow resistance of the attachment 7 can be determined by comparing the measured data with a known characteristic curve of the fan 2. The determined flow resistance corresponds to the sliding force applied by the user of the cleaning device 1 to press the attachment 7 onto the surface to be cleaned. This flow resistance or this sliding force is used to adjust the suction force of the cleaning device 1, which is adjusted by changing the speed and / or the fan output. Preferably, the suction force is adjusted to a constant value. This also occurs regardless of the fill level of the filter 14. The described method involves true control of the suction force, not just control.

  For example, the flow resistance determined during operation of the cleaning device 1 exceeds a prescribed maximum value because the attachment 7 is sucked firmly onto the surface to be cleaned or the filter 14 is completely filled. If the situation occurs, the fan output will not increase further to avoid overloading the fan 2. The defined maximum flow resistance or the corresponding maximum slip force can be set to 20 N, for example.

  To further determine the fill level of the filter 14, the determined flow resistance of the attachment 7 can be compared to a reference value that is characteristic for each specific fill level of the filter 14. For example, characteristic lines or characteristic curves determined experimentally for different filling levels of the filter 14 are also used for evaluation with respect to the various operating modes or power levels of the fan 2, if necessary.

DESCRIPTION OF SYMBOLS 1 ... Cleaning apparatus 2 ... Fan 3 ... Pressure sensor 4 ... Detection area 5 ... Connection area 6 ... Suction area 7 ... Attachment 8 ... Outlet area 9 ... Circuit board 10 ... Measurement channel 11 ... 1st edge area 12 ... 2nd End region 13 ... temperature sensor 14 ... filter 15 ... base device 16 ... operating element 17 ... slide switch 18 ... button 19 ... guide rod 20 ... hand grip element

Claims (10)

A cleaning device (1) comprising a fan (2) and a pressure sensor (3) for determining the negative pressure generated by the fan (2), in particular a household vacuum cleaner,
The cleaning device (1), wherein the pressure sensor (3) is an absolute pressure sensor.   The pressure sensor (3) has a detection area (4) arranged in the suction area (6) of the fan (2) in the connection area (5) of the attachment (7). The cleaning device (1) described. The pressure sensor (3) is arranged in the blowing area (8) of the fan (2), in particular on a circuit board (9) arranged in the blowing area (8) of the fan (2). ,
A measurement channel (10) is formed between the pressure sensor (3) and the detection region (4), and a first end region (11) of the measurement channel (10) is the pressure sensor (3). The cleaning device (1) according to claim 2, characterized in that the second end region (12) of the measurement channel (10) is in the suction region (6).   The cleaning device (1) according to claim 2 or 3, characterized in that a temperature sensor (13) is arranged in the connection area (5).   Designed to adjust the resulting suction force of the cleaning device (1) according to the negative pressure determined by the pressure sensor (3), the current fan output, and the current speed of the fan (2) 5. A cleaning device (1) according to any one of the preceding claims, characterized in that it comprises an evaluated and controlled device.   The cleaning device (1) according to claim 5, wherein the evaluation and control device is designed to further adjust the suction force according to the temperature measured by the temperature sensor (13). A cleaning device (1), in particular a household vacuum cleaner operating method, wherein the suction force of the cleaning device (1) varies according to the determined flow resistance of the attachment (7) of the cleaning device (1),
Measuring the absolute pressure in the suction area (6) of the fan (2) when the fan (2) stops;
Measuring the absolute pressure in the suction area (6) of the fan (2) when the fan (2) is activated;
Determining the negative pressure generated by the fan (2) from the difference between the measured absolute pressures;
Determining the output of the fan (2);
Measuring the speed of the fan (2);
Determining flow resistance of the attachment (7) from negative pressure, fan output and speed by comparing with known fan characteristics of the fan (2);
Adjusting the suction force of the cleaning device (1) by changing the speed of the fan (2) and / or the output of the fan according to the determined flow resistance;
A method for operating the cleaning device (1).   8. The method of operating a cleaning device (1) according to claim 7, characterized in that the fan output cannot be further increased when the specified maximum flow resistance of the attachment (7) is reached.   9. Cleaning according to claim 7 or 8, characterized in that the flow resistance of the attachment (7) currently in use is also determined according to the temperature currently measured in the connection area (5). Method of operation of device (1).   The filling level of the filter (14) arranged in the suction area (6) of the fan (2) assigns the determined flow resistance of the attachment (7) to a specific filling level of the filter (14), respectively. 10. The method of operating a cleaning device (1) according to any one of claims 7 to 9, characterized in that it is determined by comparison with a reference value.

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