EP2436294B1 - Vacuum cleaner and method for operating same - Google Patents

Description

The invention relates to a vacuum cleaner and a method for operating a vacuum cleaner according to the preambles of the independent claims.

Known vacuum cleaners are usually operated with an insertable into a dust chamber of the vacuum cleaner replaceable filter bag as the main filter. Vacuum cleaners are also known in which reusable dust collecting containers are used as the main filter. In a further development, vacuum cleaners are already known which are designed such that the user has the option of using the reusable dust collecting container or the disposable filter bag as needed.

Reduced air flow, which e.g. can be caused by a filled main filter, a blockage or a sealed suction nozzle, can lead to overheating of the blower motor motor-driven vacuum cleaners. In order to safely exclude a risk to the user and / or permanent damage to the vacuum cleaner, precautions must be taken to avoid such overheating of the fan motor.

Usually, temperature monitoring switches are used to switch off the blower motor when a limit temperature is exceeded. However, this leads to an additional cost and installation costs.

From the DE 10 2008 005 150 A1 a vacuum cleaner is known, which is operable either with or without replaceable filter bag in a dusty space, in which an electronics is provided, which compares the negative pressure in the dust chamber with a target value and initiates a fault cycle when the setpoint is exceeded. In this case, it is also provided to check, when the fault cycle is initiated, after a predetermined period of time, whether the negative pressure is still above the desired value and, in this case, to regulate the power of the vacuum cleaner.

However, this method leads to a reduction in the performance of the fan motor even if the negative pressure at the test times, eg due to the structure of the currently cleaned floor coverings, only briefly above the setpoint, but a real fault is not present.

From the DE 10 2008 010 068 A1 a device for automatic suction power control of a vacuum cleaner is known, which supplies only as much electrical power of the motor / blower unit, as is needed for optimum cleaning of the upcoming soil surface. The device thus ensures a consistent cleaning effect over the service life of the vacuum cleaner, which dust and dirt particles are always recorded with a constantly fitting suction.

From the DE 3041167 A1 a vacuum cleaner is known in which a control device measures the negative pressure in the suction air duct between the dust filter and air inlet of the suction tool and adjusts by adjusting the engine power to a predetermined negative pressure range.

The invention has for its object to provide a vacuum cleaner and a method for its operation, in which a fault case in the form of reduced air flow with low cost and installation costs can be reliably detected and a high level of user friendliness reliable protection against overheating of the fan motor is guaranteed.

This object is achieved by a vacuum cleaner and a method for operating a vacuum cleaner with the features according to the independent claims 1 and 7, respectively.

Accordingly, the vacuum cleaner comprises a blower motor, a dust chamber for receiving a main filter and a sensor system for detecting a characterizing an air flow rate. According to the invention, an electronic unit initiates a fault mode in which the blower motor is operated with reduced power when the air flow rate is continuously below a predefinable flow rate limit value for a predefinable first period of time.

In order to monitor the first period of time, the electronic unit according to the invention comprises a timer which, upon first falling below the throughput limit value or at first exceeding a first Füllgrad- or first pressure limit value is started and is reset when subsequently exceeding the flow rate limit or falling below the first Füllgrad- or first pressure limit. In this way, it is ensured in a simple manner that the fault mode is only initiated when the throughput limit value for the predefinable first time duration is continuously exceeded or the first Füllgrad- or first pressure limit for the predetermined first time duration is exceeded continuously.

According to the inventive method for operating a vacuum cleaner, a variable characterizing an air flow rate is detected and a fault mode in which the blower motor is operated at reduced power is initiated when the air flow rate is continuously below a predefinable flow rate limit for a predeterminable first period of time.

By reducing the engine power in case of failure, that is permanently reduced air flow, overheating of the fan motor is safely avoided. In contrast to an immediate shutdown of the vacuum cleaner but also in case of failure remains functional, so that an operator can still complete cleaning work begun. The continued operation of the vacuum cleaner with reduced power also has the advantage that the heat energy stored in the blower motor is still dissipated effectively, so that the vacuum cleaner after removal of the disturbance, so. after a change of the replaceable filter bag or after emptying the dust collector immediately without waiting for a cooling time is ready for use again. The fact that the fault mode is only initiated when the air flow rate is permanently and permanently limited over a longer period ensures that the engine power is really only reduced in a real fault situation.

According to one embodiment of the invention, the air flow rate is characterized by the degree of filling of the main filter. In this case, the sensor system detects a variable characterizing the degree of filling of the main filter and the electronics unit initiates the fault mode if the fill level of the main filter is continuously above a predefinable first fill level threshold value for the predeterminable first time duration. To achieve a filter change indicator, the degree of filling in many vacuum cleaners anyway detected, so that the invention can be realized without any additional hardware.

The degree of filling of the main filter can be determined particularly easily and reliably on the basis of the vacuum prevailing in the dust chamber. Accordingly, it is provided according to an embodiment of the invention that the sensor system comprises at least one analog or digital pressure sensor which detects the negative pressure in the dust chamber and the electronic unit initiates the fault mode when the negative pressure in the dust chamber for the predetermined first time period continuously above a predetermined first pressure Threshold value. On the basis of the negative pressure in the dust chamber, in addition to the degree of filling of the main filter, other restrictions of the air flow caused by other means, e.g. be detected by a blockage in an accessory, such as nozzle, suction tube or suction hose.

As an alternative, the timer can also be started when the flow rate limit value is fallen below for the first time or when the first filling level or first pressure limit is exceeded for the first time and then reset if the flow rate limit or the first pressure limit or first pressure limit are exceeded if the throughput limit value is not exceeded during the predeterminable first period of time by more than a predefinable second period of time or if the first filling level or first pressure limit value is not undershot during the predeterminable first time duration by a predefinable second time duration and / or if the throughput limit value Limit value is exceeded by a predetermined amount or the first Füllgrad- or first pressure limit is undershot by a predetermined amount.

In this way it is avoided that a short-term exceeding or falling below the limit value, which e.g. can be caused by a short-term change of the currently cleaned floor covering, immediately leading to a reset of the timer and thus possibly to a delayed initiation of the fault mode.

According to a further embodiment of the invention, the vacuum cleaner on a filter change display, by means of which a need for a change or emptying of the main filter is signaled when the degree of filling of the main filter exceeds a predetermined second Füllgrad threshold value or the negative pressure in the dust chamber exceeds a predefinable second pressure threshold. The output signals of the sensor system are used in this way both as a basis for the initiation of the disturbance mode and to display a necessary filter change. It is advantageous if the second filling level threshold value corresponds to the first filling level threshold value or the second pressure threshold value corresponds to the first pressure threshold value.

According to one embodiment of the invention, the first and / or second time periods are determined as a function of operating parameters and / or characteristics of the vacuum cleaner. As a result, the time of initiation of a disturbance mode can be optimally adapted to the specific conditions, such as e.g. the performance of the blower motor to be adjusted.

In order to reliably avoid an undesired automatic or manual increase in the power of the fan motor in the event of a malfunction, it is advantageous to allow such an increase in power only after the end of the interference mode.

After initiating the disturbance mode, the associated power reduction of the fan motor, especially for low power fan motors, may result in the limits on air flow, main filter fill level, or vacuum in the dust chamber no longer being met. In order to avoid a premature termination of the disturbance mode before the disturbance is eliminated, it may be provided that the disturbance mode is terminated only when the vacuum cleaner is switched off or disconnected from a power supply.

Further features and advantages of the invention will be explained below with reference to embodiments with reference to the accompanying figure, which shows a perspective view of a vacuum cleaner according to the invention.

In FIG. 1 a vacuum cleaner 1 is shown with a housing 2. In the rear region of the vacuum cleaner 1 two arranged on opposite longitudinal sides of the housing 2 rollers 3 are rotatably mounted. A arranged in the front region of the vacuum cleaner 1 at the top of the connecting piece 4 is attached to the housing 2. At the connecting piece 4, a suction hose 5 is connected, which is connected to a suction nozzle, not shown. In the housing 2 is a dust chamber 6. The vacuum cleaner 1 is optionally operable with a replaceable filter bag 7, preferably a disposable filter ("bag" operation) or a reusable and emptying dust collection container 8 ("bagless" operation) as a main filter in the dust chamber 6. The dust collecting container 8 is combined with a filter system 9. The dust collector 8 can be removed by opening the housing 2.

In the housing 2, a blower motor 10, a sensor system 11 and an electronic unit 12 are also provided. The sensor system 11 serves to detect a variable characterizing the air flow rate and may e.g. be executed as an analog or digital pressure sensor 13, which detects the negative pressure in the dust chamber 6 and thus indirectly the degree of filling of the replaceable filter bag 7 or the dust collector 8. Without influencing the applicability of the invention, however, the sensor system 11 can also detect another variable characterizing the air flow rate. The electronic unit 12 then evaluates the output signals of the sensor system 11. In particular, the detected variable characterizing the air flow rate is thresholded, e.g. the detected negative pressure in the dust chamber 6 compared with a first predetermined pressure threshold. If the negative pressure in the dust chamber 6 is above a predefinable first time period of e.g. five minutes continuously or at least substantially continuously above the first pressure threshold, so the electronics unit 12 initiates an interference mode in which the fan motor 10 is operated at reduced power. The power is meaningfully set such that the resulting flow rate is just sufficient to ensure safe operation of the vacuum cleaner. The first time period is monitored by a timer, which is an integral part of the electronic unit 12.

On the housing 2 of the vacuum cleaner 1 and a visible from the outside filter change indicator 14 is arranged. This serves to signal to an operator the need for a change of the replaceable filter bag 7 or emptying of the dust collector 8. For this purpose, the detected by the sensor system 11, the degree of filling of the main filter characterizing size, eg the negative pressure in the dust chamber 6, compared with a second Füllgrad- or pressure threshold, which advantageously corresponds to the first Füllgrad- or the first pressure threshold. If this second threshold is exceeded, this indicates a degree of filling of the main filter, which is a change or make a drain required, which is signaled via the filter change indicator 14.

In order to make the initiation of the interference mode tolerant even against short-term fluctuations in the air flow or the negative pressure in the dust chamber 6, it may be provided to initiate the interference mode even if the detected variables in the short term, that is not longer than a predetermined second time period above or are below the corresponding limit value and / or the corresponding limit value is not exceeded or undershot by more than a predefinable value. This may e.g. be achieved in that the timer of the electronic unit 12 is not reset in such short-term fluctuations.

In order to optimally adapt the initiation of the disturbance mode to the specific configuration of the vacuum cleaner 1 and, in particular, its fan motor 10, the first and / or second time periods may be varied depending on operating and / or characteristic quantities, such as e.g. the performance of the blower motor 10, the vacuum cleaner 1 are set.

After initiating a fault mode, a renewed increase in the power of the fan motor 10 is possible again only after the end of the fault mode. This applies both to automatic power adjustments, which may be provided in normal operation due to current operating parameters, as well as for manual power increases, which in normal operation, e.g. can be made via a manually operated power regulator. The interference mode may be e.g. be stopped by the vacuum cleaner 1 off or from a power supply, so e.g. the public power grid, is disconnected.

If the vacuum cleaner without the elimination of the error, so for example without changing the replaceable bag 7 or emptying the dust collector 8, be put back into operation, the corresponding limits are again exceeded or exceeded and after the first period of time again a disturbance mode would be initiated.

The invention has been explained by way of example with reference to a vacuum cleaner, which can be operated either with an exchangeable filter bag 7 or a dust collector 8. Of course, the invention is also applicable to vacuum cleaners, which can only be operated with one of these main filter types.

Used reference signs:

1

vacuum cleaner

2

casing

3

castors

4

spigot

5

suction

6

dust chamber

7

AC filter bag

8th

dust collection

9

filter system

10

blower motor

11

sensor system

12

electronics unit

13

pressure sensor

14

Filter change indicator

Claims (14)

1. Vacuum cleaner (1) with

   - a fan motor (10),

   - a dust chamber (6) for receiving a main filter (7; 8) and

   - a sensor system (11) for detecting a variable characterising an air throughput,

   - an electronics unit (12), which initiates a fault mode in which the fan motor (10) is operated with reduced power if the air throughput, for a predeterminable first period of time lies without interruption below a predeterminable throughput threshold value,

   characterised in that the electronics unit (12) includes a timing element for monitoring the first period of time, which is started the first time that the throughput threshold value is undershot or the first time that a first fill level or a first pressure threshold value is exceeded and is reset when the throughput threshold value is subsequently exceeded or the first fill level of the first pressure threshold value is undershot.
2. Vacuum cleaner according to claim 1, characterised in that

   - the air throughput is characterised by the fill level of the main filter (7; 8),

   - the sensor system (11) detects a variable characterising the fill level of the main filter (7; 8) and

   - the electronics unit (12) initiates the fault mode if the fill level of the main filter (7; 8) lies without interruption for the predeterminable first period of time above a predeterminable first fill level threshold value.
3. Vacuum cleaner according to one of claims 1 or 2, characterised in that

   - the air throughput and/or fill level of the main filter (7; 8) is characterised by a vacuum in the dust chamber (6),

   - the sensor system (11) includes a least one analogue or digital pressure sensor (13) which detects the vacuum in the dust chamber (6) and

   - the electronics unit (12) initiates the fault mode if the vacuum in the dust chamber (6) lies without interruption above a predeterminable first pressure threshold value for the first period of time.
4. Vacuum cleaner according to one of claims 1 to 3, characterised in that the electronics unit (12) has a timing element for monitoring the first period of time which is started the first time that the throughput threshold value is undershot or the first time that the fill level or the first pressure threshold value is exceeded and is reset when the throughput threshold value is subsequently exceeded or the first fill level or first pressure threshold value is subsequently undershot, if the throughput threshold value is not exceeded for longer than a predeterminable second period of time during the predeterminable first period of time or the first fill level or the first pressure threshold value is not undershot for longer than a predeterminable second period of time during the predeterminable first period of time and/or if the throughput threshold value is exceeded by a predeterminable amount or the first fill level or first pressure threshold value is undershot by a predeterminable amount.
5. Vacuum cleaner according to one of claims 2 to 4, characterised in that a filter change display (14) is provided, with the aid of which the necessity of a replacement or an emptying of the main filter (7; 8) is signalled if the fill level of the main filter (7; 8) exceeds a predeterminable second fill level threshold value or the vacuum in the dust chamber (6) exceeds a predeterminable second pressure threshold value.
6. Vacuum cleaner according to claim 5, characterised in that the second fill level threshold value corresponds to the first fill level threshold value or the second pressure threshold value corresponds to the first pressure threshold value.
7. Method for operating a vacuum cleaner (1) with a fan motor (10) and the dust chamber (6) for accommodating a main filter (7; 8), in which

   - a variable characterising an air throughput is detected;

   - a fault mode is initiated in which the fan motor (10) is operated with reduced power if the air throughput lies below a predeterminable throughput threshold value without interruption for a predeterminable first period of time,

   characterised in that

   - a timer for monitoring the first period of time is started the first time that the throughput threshold value is undershot or the first time that a first fill level or first pressure threshold value is exceeded and is reset when the throughput threshold value is subsequently exceeded or the first fill level or first pressure threshold value is subsequently undershot.
8. Method according to claim 7, characterised in that a variable characterising the fill level of the main filter (7; 8) is detected and the fault mode is initiated if the fill level of the main filter (7; 8) lies without interruption above a predeterminable first fill level threshold value for a predeterminable first period of time.
9. Method according to one of claims 7 or 8, characterised in that a vacuum in the dust chamber (6) is detected in the fault mode is initiated if the vacuum in the dust chamber (6) lies without interruption above a first predeterminable pressure threshold value for the predeterminable first period of time.
10. Method according to one of claims 7 to 9, characterised in that the fault mode is initiated if the throughput threshold value is undershot without interruption for the predeterminable first period of time or the first fill level or first pressure threshold value is exceeded without interruption for the predeterminable first period of time.
11. Method according to one of claims 8 to 10, characterised in that the fault mode is initiated if the throughput threshold value is not exceeded for longer than a predeterminable second period of time during the predeterminable first period of time or the first fill level or first pressure threshold value is not undershot for longer than a predeterminable second period of time during the predeterminable first period of time and/or the throughput threshold value is not exceeded by more than a predeterminable value during the first period of time or the first fill level or first pressure threshold value is not undershot by more than a predeterminable value during the predeterminable first period of time.
12. Method according to one of claims 7 to 11, characterised in that the first period of time is defined as a function of operating parameters and/or characteristic variables of the vacuum cleaner (1).
13. Method according to one of claims 7 to 12, characterised in that a manual or automatic increase of the power of the fan motor (10) is only allowed after ending of the fault mode.
14. Method according to one of the preceding claims, characterised in that the fault mode is ended when the vacuum cleaner (1) is switched off or is disconnected from a power supply.

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