Method of cleaning the filter of a travelling floor cleaning machine

0001The invention relates to a method for cleaning the Filter of a vacuum system of a mobile floor cleaning machine by interrupting the floor cleaning operation and supplying mechanical vibrational energy to the supporting frame of the filter, the a firmly but releasably connected with the frame support member and attached thereto, the filter material having contains filter assembly, the vibration energy which has resonant frequency of the filter assembly, and to a correspondingly constructed mobile floor cleaning machine,

0002Mobile floor cleaning machines with suction systems are available in different versions and both Aufsitzermaschinen as well as hand-held machines. In so-called vacuum sweepers throws a sweeping brush or roller taken from the ground Dirt in a dirt collecting, and of the loaded the sweeping brush or roller swirled dust Air is drawn through at least one filter before it again is directed into the surrounding air, the dirt constituents to be freed. In is known as street sweepers the dirt by a suction generated by the air flow from received ground and transported in a dirt collecting, whereupon also in some cases purification of air by means of at least one filter before the air re- get into the environment. The information to be in all cases deposition of dirt components on the material of the filter or Remove gradually leads to a reduction of permeability of the filter. It is therefore necessary to Kehrsaugbetrieb or Suction, ie interrupting the floor cleaning operation temporarily, To make a cleaning of the filter. This cleaning can be effected by mechanical scrapers on the Filter material, such as by concertina shaped fold formed fins of a plate filter or a cartridge filter, be conducted. It is also known that a cleaning thereby carry out that one of the holding frame of the filter mechanical vibration energy supplies, for example by subjecting it to a jogger, so coupled to a motor, on the motor shaft For example, an eccentrically mounted mass is. Such are Vibrator both disc filters as well among others used in bag filters, and it is already known (GB-B-1,224,068), shaking at the resonant frequency of the filter arrangement make. Here, the resonant frequency of either fixed according to the structure of the filter assembly or adjusted during operation.

0003While the cleaning means in engagement with the filter material Candidate strippers is of limited effectiveness and in particular to wear in the area of ​​the filter material and thus to can cause local loss of filter efficiency, the use Vibrator by less harmful to the structure of the filter material, but has had limited impact because the filter material adherent contaminant in this way only imperfectly be solved unless the filter cleaning operation extends over a very long time. However, this has then a suitably long interruption of the actual floor cleaning operation the floor cleaning machine itself. The known Shake at the resonant frequency of the filter arrangement Although could eliminate the disadvantage of a long cleaning process, however, is significantly less effective in practice. This has its origins in the fact that the effective resonant frequency of the Filter assembly of numerous factors, on the one hand manufacturing tolerances are (variations in the composition of Filter material, tolerances of the retaining frame components, tolerances the vibration generator), and on the other hand during operation of the Floor cleaning machine occur. The latter is located in particular that contained in the filter assembly dirt lot. In accordance with the filter assembly firmly set "Resonant frequency" is this only in rare cases said given the respective resonance frequency of the cleaning case Filter assembly match. But since each fact existing resonance frequency can not be measured, can also frequency adjustment for each cleaning operation only by way of trials. Again, this is so time-consuming that one actually on the attempt of shaking with resonance frequency may waive the same.

0004The object of the invention, the mechanical by supplying Vibrational energy to the support frame takes place cleaning of the filter to improve a floor cleaning machine so that in a relatively short time a very effective separation of the adhering to the filter material dirt is effected.

0005To achieve this object, a method of the aforementioned Type according to the invention configured such that the opposite its holder vibration-isolated, limited beweggbaren Holding frame vibration energy is supplied at a frequency, at least four times a during a cleaning operation Frequency range passes through, in which the resonance frequency of the Support member attached filter assembly is located. Accordingly, a mobile floor cleaning machine of the type of interest According to the invention configured such that the holding frame elastically is supported and held movable limited and the Vibrator charged with vibrational energy at a frequency is, at least during a cleaning operation four times through a frequency range in which the resonance frequency the filter assembly is located.

0006In the inventive solution therefore is the famous "theoretical" Resonant frequency of the filter assembly basis, however, taken into account that in practice this not for the each cleaning procedure in force "real" resonance frequency is, for example, by manufacturing tolerances and also depends on the degree of the dirt loading of the filter assembly. By traversing a frequency range not only the "Theoretical", but the "real" resonance frequency contains, it is ensured that the holding frame of the filter and thus the filter so applied vibrational energy is that its filter assembly that includes the filter material, at least four, preferably six to ten times, with their respective "actual" resonant frequency is excited. This leads to a maximum deflection of the filter material in both Movement of the vibratory motion and thus, in particular to a strong acceleration of the dirt on the Filter material in reversing the direction of movement of the filter material, what a particularly good separation of dirt from has filter material result. Through this multiple energizing with the resonant frequency therefore results in a relatively short Time a far better separation of dirt from is filter material possible than when the filter means a vibrating motor with solely by the speed of the Vibrating motor given substantially constant, but only lying resonant frequency near the "actual" Frequency is applied.

0007The frequency range to be traversed must be both sufficiently be large, so that the "real" resonance frequency again this is, and on the other hand it is as small as possible be so at the desired slow passage through the frequency range and given by relatively long Excitation at the resonant frequency, the time intervals between the successive passage of the "actual" Resonant frequency are as short as possible, the entire cleaning process thus requires relatively little time. preferably Embodiment, therefore, the upper limit frequency of the frequency range a maximum of 30% greater than the "theoretical" resonant frequency, preferably not more than 20% and in most preferably a maximum of 10%. Accordingly, the lower limit frequency of the frequency range is smaller by a maximum of 30% than the "theoretical" resonant frequency and preferably a maximum of by 20% and very particularly preferably by a maximum of 10%. The case underlying "theoretical" resonance frequency is, as already mentioned, for the filter assembly of a filter of interest Type assumable resonant frequency, so a Mean that neither deviations due to tolerances of the filter material and the remaining structure still changes Resonant frequency into account by depositing dirt particles.

0008If the floor cleaning machine containing a disk filter arranged in a rectangular or square support frame is that, as already mentioned above, elastically supported and is held movable limited, preferably the Exposure to vibration energy so that the support member supported shouldered, consisting of filter material lamellenförmigem Filter assembly in the plane of the plate and in the direction perpendicular to Longitudinal extent of the slats is vibrated.

0009When the floor cleaning machine comprises bag filter having a cylindrical support member and a filter assembly of tubular Filter material and an elastic strainer if necessary with an improving the vibration behavior, additional mass exhibit, this can ihrerer either towards the longitudinal axis displaced or in the direction transverse to the longitudinal axis in vibrations will.

0010The invention is described below using the exemplary embodiments figures showing more detail.<dl tsize="7"><dt>figure 1</dt><dd>shows a side view of a floor cleaning machine in the form of a conventional vacuum sweeper, in the the invention can be used.</dd><dt>figure 2</dt><dd>shows schematically the mounting of a plate filter in a filter housing of a mobile floor cleaning machine.</dd><dt>figure 3</dt><dd>schematically shows a bag filter of a mobile Floor cleaning machine which is mounted on a holding plate is.</dd><dt>figure 4</dt><dd>shows in a representation corresponding to Figure 3 a along its longitudinal axis with vibrational energy acted baghouse.</dd><dt>figure 5</dt><dd>shows in a representation corresponding to Figure 3 a is acted upon transverse to its longitudinal axis with vibrational energy Baghouse.</dd></dl>

0011The vacuum sweeper schematically illustrated in Figure 1 has a frame 1 on which a front wheel 3 and rear wheels 4 are supported and which provides for a service area 2 is that a driver's seat, a steering column attached to a Steering wheel and the corresponding operating elements for the comprises operating the vacuum sweeper. Below the driver's seat are usually required for the power supply Batteries or an internal combustion engine housed. On the rear part of the frame 1 are in the range 8 for driving operation and the suction required aggregates, in particular a fan and the necessary air ducts provided and in this area there is also a dirt receptacle including the or the associated filter. Below the frame 1 a sitting at the front of the cleaning operation in engagement with the floor to be cleaned standing, revolving moving side brush 6 for supplying located on the floor of the Dirt to the center and in front of a rotationally driven, in Figure 1 of a cover 9 covert Kehrwalze that the Dirt through a suction guide 7 in the dirt receptacle throws.

0012The construction and operation of such a vacuum sweeper is generally known and therefore requires no further explanation.

0013As already mentioned, the particulate matter entraining the fluidized Air prior to its discharge into the environment by at least a filter passed to entrained at this dirt deposit, so that they do not reach back into the ambient air. For this purpose, in such a vacuum sweepers Plate filters, bag filters, cartridge filters, etc. scheduled be, and it is possible to use either a single filter to use or multiple filters in succession in the flow path to arrange. The will prevent depositing on the filter material of this filter Dirt reduces naturally the air permeability, so that it is necessary from time to time a make filter cleaning, by adhering dirt or the adhesive, composed of dirt Filter cake is released from the filter material.

0014In the schematic representation according to Figure 2 is a filter housing 10 shown a vacuum sweeper, which in operation from below is traversed upwards laden with dirty air. In the Filter housing 10 is a support frame 11 disposed of on himself elastic supports 12 rests on the filter housing 10th These supports can be formed by coil springs, in which the Holding frame 11 extend fixed mandrels of the situation Holding frame set 11 in the filter housing 10th The holding frame 11 is otherwise with a gap in the filter housing 10 is arranged, and this gap is by a circumferential elastic Seal 13 is sealed, the passage of unfiltered Air prevented in this area.

0015a crossmember extending at the underside of the holding frame 11 17, at a schematically illustrated motor vibrator 18 is held. This is an electric motor, the carries an eccentric mass on its armature shaft. Such Vibrator are known. Optionally, the rotating Driving an eccentric mass shaft carrying a by alternating magnetic field movable piston, a pneumatic or similar hydraulic cylinder serve.

0016In holding frame 11 removably sits a plate filter, the frame-shaped fixed support member 14 by means of a clamping 15 and whose supported shouldered in the support part 14 of filter assembly formed by accordion-like folding of the filter material Fins 16 serving carried the passing of the air retain dirt. Therefore, deposits in Kehrsaugbetrieb at these fins from dirt, the air permeability, the the filter material is increasingly reduced.

0017Is a certain degree of air impermeability achieved interrupts the operator of the floor vacuum sweeper cleaning operation and initiates a filter cleaning process. To this end, The shaker 18 is activated so that it by its rotation Vibrational energy transferred to the holding frame eleventh The vibration energy acts in the plane of Figure 2, so that the Support frame 11 and thus the plate filter in the plane of the drawing are reciprocated. The electric motor 18 is thereby controlled to be several times, at least four times, preferably six to ten times, a speed range passes, is selected such that in its passage through an excitation the filter assembly with its resonant frequency takes place. at this passage of the resonance frequency increases the vibration amplitude the filter elements 16 substantially over a Excitement outside the resonant frequency. The significantly increased Deflections of the filter elements 16 in the region of the resonant frequency result in effective separation of the dirt.

0018In a practical experiment, the jogger was repeatedly with Speeds of 4000 r / min to 5000 r / min and vice versa operated, around a plate filter, in which the resonance frequency of the filter arrangement was approximately 75 Hz, the area of ​​this resonance frequency to excite. In this case, the displacements of the filter elements increased, which when subjected to vibrational energy outside the resonant frequency of a deflection of about ± 2 mm learned to a deflection of about ± 6 mm to ± 7 mm, giving a had pronounced increase in the cleaning effect the result.

0019In Figure 3, a bag filter is shown schematically, with the its provided at the upper end of the cylindrical support member, or Headpiece 24 is secured to a holding plate 31, whose function corresponding to that of the holding frame 11 of FIG. 2 At the Support member 24 is a filter assembly of tubular filter material 26 and enclosed by this, elastically deformable Filter basket 29 attached to the lower end of additional mass 30 attached.

0020To carry out a filter cleaning operation, as shown in Figure 4 indicated, the holding plate 31 and thus the support part 24 with vibrational energy along the longitudinal axis of the bag filter applied. This results, as can be seen in Figure 4, an alternating shortening and stretching of the additional mass 30 bearing the filter basket 29 and of the tubular filtering material 26 and thus a corresponding deformation of the Peripheral wall, which is particularly pronounced when the supplied Vibrational energy in the range of the resonance frequency of the Filter assembly is. The occurring by very pronounced Deformation promotes the cleaning process in a considerable extent.

0021A bag filter according to Figure 4, as indicated in Figure 5, with its support member or head 24 also at a 'Be supported holding plate 31 for transmitting vibrational energy transversely suited to the longitudinal axis of the bag filter is suspended. With such a supply of vibrational energy performs the filter assembly, as indicated in Figure 5, bending vibrations from which, of course particularly pronounced are, when vibration energy in the range of the resonant frequency the filter arrangement is supplied. Here arises a pronounced cleaning effect.