EP0755216B1 - Vacuum cleaner with suction power indicator - Google Patents

Abstract

The invention relates to a vacuum cleaner (1) with a blower (10), a filter bag (9) and a suction power indicator (14) which is controlled by detecting the pressure difference; in order to fit a vacuum cleaner as claimed with an indicator which indicates the relative suction power independently of the attachment used and thus also of the effective air passage, it is proposed that the pressure difference be derived from the depression in a suction channel (28) upstream of the filter bag (9) and the overpressure downstream of the blower (10).

Description

The invention relates to a vacuum cleaner with a Blower, a filter bag and a suction power indicator, by detecting a pressure difference is controlled, the pressure difference from the negative pressure in the suction channel in front of the filter bag and overpressure after the blower is formed.

Vacuum cleaners are known, in general as an indicator of the increasing clogging of the filter bag by sucked up dust by the throttling effect pressure drop caused by the filter material be pulled over the filter bag. This pressure drop becomes working by means of analog or digital Ads displayed as a feature of filter clogging. Under the limitation of constant blower output and This display is the constant nozzle processing point correctly. Devices with variable motor power can Ads that only show the pressure drop across the filter bag take into account, correct only in one operating point Show. In general, this is the point max. Engine power, so at a smaller chosen Too little filter clogging is displayed becomes. In addition, there is a change in the work panel for the blower, as z. B. by different Floors and to an even greater extent by changing the Working nozzle is caused, the display error that occurs with exclusive measurement of the differential pressure even bigger over the filter bag. Both with clean as well as when the filter bag is clogged changes the pressure drop across the filter bag when changing the Large suction attachment.

Furthermore, a vacuum cleaner is included in EP-A1-0365191 a suction power indicator known. This suction power indicator is determined by determining a pressure difference controlled, to determine this pressure difference input side of a filter bag, i.e. in the before arranged suction channel, the vacuum and after a Blower the overpressure is measured. These from sensors Pressure values are measured using a microprocessor evaluated and displayed.

Furthermore, a suction power display is known from GB-A-2012158, which applied a vacuum to both sides Has membrane. To determine the pressure difference the vacuum inside the filter bag and the negative pressure outside the filter bag, i.e. in the Area of the filter chamber, tapped. These oppressions each act on one of the opposite surfaces the membrane, which corresponds to the pressure difference moved a pointer.

The object of the present invention is a generic Vacuum cleaner with a mechanical one Provide ad regardless of which one is used Attachment device and therefore also independent of the work panel shows the relative suction power.

This task is solved by the main claim specified invention.

The subclaims represent advantageous developments represents.

Due to this configuration it is achieved that regardless of the attachment used, the relative Suction power via mechanically working means for Advertisement is brought. This is achieved in that the pressures on the opposite faces of one in Dependence of the pressures movable, closed Disc are switched.

The position of the movable For example, disc within the device be recognized by means of a viewing window. The display device can be designed so that this for example a cylinder in which the disc is freely movable. To the two opposite Surfaces of the pane act on the one hand Negative pressure in the suction channel and secondly the excess pressure after the blower. To seal the used Pressures against each other can be bellows, for example be used. Depending on the preset blower output and filling level of the filter bag and the like dependent pressures takes the disc in the cylinder a position which, for example, via a viewing window can be recognized, which with a scale can be provided. This results in one Vacuum cleaner with variable motor power, one mechanical working display of the current suction power of the device depending on the preset Motor power and the degree of filling of the filter bag, however independent of an upstream Front attachment always indicates the relative suction power. An embodiment is preferred in which the Decrease in pressure after the blower, but before the following Flow resistances and possibly in front of a blow-out filter element he follows. With a clean filter bag and max. Blower output becomes independent of the work panel reached a display value of 100%. With a clean filter bag and reduced fan power will also A correspondingly reduced value regardless of the aperture displayed. With increasing clogging of the filter bag the display value drops accordingly. Here, at smaller working panels have a larger relative suction power are displayed than with larger f-numbers, because the air speeds z. B. in a crevice nozzle even with a largely clogged filter bag are high to collect dust. The negative pressure in the Suction channel before the fan and the overpressure after the Blowers are detected in a device which analogue or digital, depending on the pressures available the current, relative suction power for display brings. Such a device can, for example be designed so that the suction power indicator off an addition of the absolute values of the two pressures results. If a max. Fan power the two pressures add up to a suction power display of 100%. The fan power is on reduced by half, this results in a corresponding reduced vacuum in the suction channel and a reduced overpressure after the fan, their addition an indication of the suction power of 50%. Outgoing from a preset max. Fan performance occurs when the filter bag becomes increasingly clogged a decrease in the vacuum in the suction channel. The Adding the pressures results in a smaller value, which is displayed, for example a current relative suction power of 80%. Will be under another attachment with these given circumstances upstream of a smaller work panel, so leads this leads to an increase in the air speed in the area of the suction channel, which also means the negative pressure in the Suction channel increases, while lowering the Overpressure after the blower. However, the latter sinks not to the same extent as the overpressure in the suction channel increases. This leads to a higher result of the Adding the pressures than the original, larger ones Working aperture, which also makes a larger relative Suction power is displayed. It is also desirable, because with attachments with a small working panel, such as B. a crevice nozzle, also largely clogged filter bag the air speed still is high enough to hold dust. In an advantageous Training of the subject of the invention is provided that the negative pressure a correction factor is activated. This can be done, for example be realized that in the device in which the absolute values of the pressures are added, the value of the A spring pressure value of a ring spring or the like is opposed. Advantageously the display is designed as an analog display. To at turned off the vacuum cleaner, especially to move the disc in a basic position, which Basic position causes a performance display of 0% further provided that the disc is one-sided is spring loaded. Finally, it is advantageous provided that the correction factor by different Connection surfaces for the two pressures the opposite sides of the disc is. The pads on the opposite Surfaces of the disk can be chosen in this way, for example be that the area on which the overpressure after the Fan acts, is larger than the surface, acts on the negative pressure in the suction channel. Prefers will be training in which the pads circular, according to the cylindrical shape of the device, are shaped. With such a trained The suction power display calculates the display value by adding the absolute values of the negative pressure in the suction channel and overpressure behind the blower, which overpressure multiplied by the correction factor is. The latter in turn is calculated from the square the pressure gauge ratios of the two connection surfaces to each other.

Fig. 1

einen erfindungsgemäßen Staubsauger mit einer in einem Gerätegehäuse angeordneten Saugleistungsanzeige,

Fig. 2

eine schematische Darstellung des Gerätegehäuses, partiell au gebrochen, zur Darstellung der Anordnung der Saugleistungsanzeige in dem Gerätegehäuse,

Fig. 3

eine Ausschnittsdarstellung des Gerätegehäuses im Bereich der Saugleistungsanzeige,

Fig. 4

den Schnitt gemäß der Linie IV-IV in Fig. 3,

Fig. 5

ein Diagramm zur Darstellung des prinzipiellen Verlaufs eines Unterdruckes in einem Saugkanal vor einem Gebläse und eines Überdruckes nach dem Gebläse und

Fig. 6

verschiedene Anzeigenkennlinien der Saugleistungsanzeige.

The invention is further explained below with reference to the accompanying drawing, which, however, only represents an exemplary embodiment. Here shows:

Fig. 1

a vacuum cleaner according to the invention with a suction power display arranged in a device housing,

Fig. 2

1 shows a schematic illustration of the device housing, partially broken away, to show the arrangement of the suction power display in the device housing,

Fig. 3

a sectional view of the device housing in the area of the suction power display,

Fig. 4

the section along the line IV-IV in Fig. 3,

Fig. 5

a diagram showing the basic course of a negative pressure in a suction channel before a blower and an overpressure after the blower and

Fig. 6

different display characteristics of the suction power display.

The vacuum cleaner 1 shown is designed as a hand-held device. It has a housing 2, to which a top Device handle 3 connects with end handle 4. In Transition area between handle 4 and handle 3 there is a power potentiometer 5, which on the one hand to switch the vacuum cleaner on and off and on the other hand for variable fan motor power setting serves. The electrical cable connection is with the number 6 designated.

The housing 2 is divided into a motor housing 7 and an overlying chamber 8 for receiving a filter bag 9. In the motor housing 7 that is Blower 10 arranged, which by means of a blower motor 11 is driven (see FIG. 2).

The motor housing 7 goes into a pipe coupling on the underside 12 over which the air flow connection to a suction nozzle 13 manufactures.

Regarding the suction nozzle 13 it is shown in the Example of a so-called suction / brush nozzle, the contains a brush roller in the nozzle mouth, which over a separate drive is set in rotation. There are other attachments can also be used, such as a crevice nozzle or an upholstery nozzle.

The blower motor 11 is connected downstream of the filter bag 9 and works in a known manner, therefore sucks the dust air through the above the motor housing 7 tumbled filter bag 9, which directly via a suction channel 28 with a pipe coupling 12 through the suction channel.

The blower 10 is furthermore a blow-out filter 32 downstream, via which the cleaned air after outside occurs.

The cross section of the housing 2 is rectangular throughout with poorly developed broadsides and the like Narrow sides. In Fig. 1 is the vacuum cleaner of the To see the narrow side. 2 shows a partial Broken view on a broadside.

In the area of the narrow side of the housing shown in FIG. 1 2, a suction power indicator 14 is arranged in this.

The latter consists essentially of a cylindrical Body 15, in which a movable, closed Disk 16 is mounted. On the opposite Surfaces 17, 18 of the disk 16 are switched, as a result of which the disk 16 depends on the pressures positioned within the cylindrical body 15. For Readability of the current position of the disc 16 inside the cylindrical body 15 the latter has a slot-shaped opening 19 through which a pointer 20 arranged on the disk 16 engages.

The cylindrical body 15 is immediately behind the Housing wall of the motor housing 7 arranged. In the area of the slot-shaped opening 19 of the cylindrical Body 15, the motor housing 7 has a viewing window 21, whereby the current position of the disc 16 can be recognized from the outside with the aid of the pointer 20.

For improved readability is in the area of the viewing window 21, d. H. in the display area of the pointer 20 the outer surface of the cylindrical body 15 a scale or the like provided.

On the face side, the body has 15 cylindrical sockets 22,23 for connecting pressure lines 24,25, one Pressure line 24 leads to a connection point 26, which behind the blower 10, but in front of the blow-out filter 32 is arranged. The pressure line 25, however, leads to a connection point 27 in the area of the pipe coupling 12 with the suction bag 28 connecting the filter bag 9.

To seal the pressures used within the cylindrical body 15 against each other are bellows 29.30 used. These each extend from the part of the protruding into the cylindrical body Stubs 22 and 23 starting from the respective Bellows 29,30 facing surfaces 17 and 18 of the Disc 16.

The sealing of the pressures against one another can also, for example through membranes or through adapted cylinder guides for the different piston diameters be achieved.

The circular surfaces 17, 18 are of different sizes educated. It can be seen from Fig. 4 that the Radius of the pad 17 is approximately twice as large as that of the pad 18. By the area ratio of large and small piston diameters or mating surfaces a correction factor is determined. This is calculated by the square of the ratio of large to small diameter.

The sealing of the pressures against one another can also, for example by membrane or by adapted cylinder guides achieved for the different piston diameters will.

In the area of the bellows 30 there is also one Compression spring 31 which is located at one end of the Inside of the cylindrical body 15 in the area of Supporting nozzle 23 and the other end on the disc 16. It includes the bellows 30. This compression spring 31 serves as an auxiliary spring to achieve a basic position the suction power display 14, according to that in FIG. 4 shown position.

The negative pressure in the suction channel is via the pressure line 25 28 in front of the filter bag 9 and via the pressure line 24 the overpressure after the blower 10, but before subsequent ones Flow resistances and the blow-out filter 32 on the respective pads 17 and 18 of the disc 16 switched. Depending on the size of the pressures or depending on The height of the pressure difference moves the disc 16 against the spring force of the compression spring 31 from that in FIG. 4 shown starting position in one, the relative Suction power corresponding position. In the shown Starting position is, for example, the one shown Value of the suction power display 14 on the scale 0%. At Max. Deflection of the pointer 20, i. H. at max. shift the disc 16 in the direction of the nozzle 23 a suction power of 100% is displayed.

The two pressures, ie the negative pressure in the suction channel 28 in front of the filter bag 9 and the positive pressure behind the blower 10, are linked, the display value A resulting from the addition of the absolute value of the negative pressure P _s and the positive pressure P _d , which with the correction factor K is multiplied.

Due to this configuration, a suction power display is required 14 given, regardless of the attachment used (Suction / brush nozzle, crevice nozzle, etc.) the relative Brings suction power analog to the display. With clean Filter bag and max. Fan performance becomes independent from the aperture specified by the front attachment reached an ad value of 100%. With a clean filter bag 9 and less, by the power potentiometer 5 preset blower output is also independent of the aperture a correspondingly reduced value is displayed. The display value drops as the bag becomes blocked accordingly, with smaller work panels a larger relative suction power is displayed than with larger f-numbers, because the air speeds e.g. B. in a crevice nozzle also largely clogged filter bag 9 are high enough to dust to record.

The basic course of the pressures in a vacuum cleaner 1 over the volume flow gamma is shown in FIG. 5 in an example. Here, the characteristic of the overpressure after the fan 10 _is denoted by P _d . The characteristic curve P _s1 shows the course of the negative pressure in the suction channel 28 with a preset max. Performance and new filter bag 9. A further characteristic curve P _s3 shifted parallel to this characteristic curve also shows the course of the negative pressure with a new filter bag 9, but with a preset min. Fan motor power 11.

Finally, a characteristic curve P _{s2 is} shown, which represents the course of the negative pressure with a preset maximum output and a blocked filter bag 9.

The diagram is based on two given volume flows gamma 'and gamma' 'explained in more detail, the volume flows in direct dependence on the f-number of the the respective attachment used.

With a volume flow gamma 'add at a preset max. Blower power and new filter bag 9, the absolute values of the negative pressure P _s1 and the positive pressure P _d . The values are entered in the diagram with a ₁ for the absolute negative pressure value and with b for the absolute positive pressure value. If the preset blower output is reduced to a minimum, the characteristic curve of the negative pressure shifts parallel to the zero point (characteristic curve P _s3 ). It can be seen that the absolute vacuum value a ₃ decreases. The respective addition of a ₁ and b or a ₃ and b gives the absolute value of the total pressure, which is displayed directly in the suction power display 14 via the pointer 20 attached to the disk 16, but here not the absolute pressures, but rather the performance is shown in percent. Furthermore, with a selected volume flow gamma 'it can be seen that with a preset max. Blower output and clogged filter bag 9, the characteristic curve of the vacuum P _s2 runs in such a way that an absolute value a ₂ results, which is between the absolute values a ₁ and a _{3 in} terms of size.

A reduction in the volume flow, as can be seen from the diagram in FIG. 5, results in a reduction in the overpressure P _d with a simultaneous increase in the respective underpressure P _s . With an assumed volume flow gamma ″, absolute vacuum values a _{1 ′} , a _{2 ′} and a _{3 ′} are thus obtained for the respective cases. It can be seen that the result of adding the absolute values at a volume flow gamma '' is greater than when adding the absolute values at a volume flow gamma '. This is particularly the case when, for example, as shown by the characteristic curve P _s2 , a max. Blower power is preset and the filter bag 9 is largely filled. Here the absolute values a _{3 '} and b' add up to an absolute pressure value which is greater than when the absolute values a ₂ and b are added in the case of a volume flow gamma '. As a result, a greater relative suction power is displayed, with the same preset blower power and degree of clogging of the filter bag 9. This is desirable because the air velocities z. B. in a crevice nozzle even with a largely clogged filter bag 9 are still high enough to absorb dust. The relative suction power of the vacuum cleaner 1 when the filter bag 9 is full is accordingly greater with smaller f-numbers than with larger f-numbers.

The diagram shown in FIG. 6 shows, in a simplified manner, the dependency on the preset blower output, the degree of filling of the filter bag 9 and the f-number B of the front attachment on the display value A. Four characteristic curves are shown here, whereby K ₁ denotes a display characteristic curve, with a preset max. Blower output and new filter bag 9. The characteristic curve K ₃ shows the course at a preset min. Blower output and new filter bag 9. With K ₂ and K ₄ , display characteristic curves are designated which represent the course of the display when the filter bag 9 is full, the maximum blower output being preset at K _{2 and} the minimum blower output being preset at K ₄ .

By selecting the correction factor already mentioned, the characteristics of the suction power display 14 can be adapted to the desired display characteristics. It can be seen from FIG. 6 that the characteristic curves K ₁ and K _3, regardless of the number of f-stops, each result in a display value which corresponds to the preset value of the blower output. This means that with a preset max. Blower power, the suction power display 14 always shows a relative suction power of 100% in accordance with the characteristic curve K ₁ regardless of the number of f-stops. The display falls correspondingly lower at the preset min. Blower output. Regardless of the f-number, a value of the relative suction power of 50%, for example, is always displayed here.

With a preset max. Blower power and filled filter bag 9, the characteristic curve K ₂ depends on the number of f-stops B. It can be seen that the display value A is always below the display value when the filter bag 9 is empty (characteristic curve K ₁ ), the relative suction power being displayed with a smaller f-number is larger than with a larger f-number. The characteristic curve K ₄ (preset minimum blower output and clogged filter bag 9) is essentially the same as the characteristic curve K ₂ . However, the curve is flatter than the latter. It can also be seen here that the display of the relative suction power is always below the value of the characteristic curve K ₃ and that a larger relative suction power is displayed with a small number of f-stops.

Claims (6)

1. Vacuum cleaner (1) having a fan (10), a filter bag (9) and a suction power display (14) controlled by detection of the pressure difference, the pressure difference being produced from the partial vacuum (P_s) in a suction channel (28) ahead of the filter bag (9) and the excess pressure (P_d) after the fan (10), characterised in that the pressures (P_s and P_d) are connected to the opposite faces (17, 18) of a closed disk (16) capable of movement as a function of the pressures (P_s and P_d).
2. Vacuum cleaner according to Claim 1, characterised in that the decrease in pressure ensues after the fan (10) but ahead of the following flow resistances and possibly ahead of an outflow filter element (32).
3. Vacuum cleaner according to Claim 1, characterised in that a correction factor (K) is applied to the partial vacuum (P_s).
4. Vacuum cleaner according to one or more of the preceding claims, characterised in that the suction power display (14) is an analogue display.
5. Vacuum cleaner according to one or more of the preceding claims, characterised in that the disk (16) is acted upon by a spring on one side.
6. Vacuum cleaner according to one or more of the preceding claims, characterised in that the correction factor is set by means of different connecting areas (17, 18) for the two pressures (P_s and P_d) on the opposite sides of the disk (16).

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