APPARATUS FOR COLLECTING DUST PARTICLES

Abstract: Vacuum cleaner for industrial and domestic applications, in which the sucked up dust is collected in a vessel filled with water. The necessary sucking action is generated with an air pump or with a venturi, located in a suction tube in front of the vessel. In order to realize complete washing out of the dust, the vessel is provided with at least one grid through which the air bubbles can escape.

Description: Apparatus for collecting dust particles The invention relates to a suction apparatus for sucking up and collecting dust particles, comprising a suction tube, suction means and a collector unit connected to the suction tube . A suction apparatus of this type is known from US 5,228, 244. In the known suction apparatus the collector unit comprises a dust collecting bag, in which the dust is collected while the air, carrying the dust, escapes through the wall of the bag. The disadvantage of a bag is that small dust particles will escape through the wall of the bag. This may be especially disadvantageous if the dust particles are harmful to the health when inhaled. This is the case for example if the dust is released while processing stone, because this type of dust tends to cause silicosis. Even relatively harmless dust, like home dust, may be detrimental to the health for certain individuals. Apart from this, the problem exists that especially very fine dust quickly stops up the dust bag, as a result of which it must be replaced or beaten. Beating a dust bag must be considered very detrimental as the dust will yet be released. More in general, fact is that a dust bag must be emptied periodically and that on these occasions part of the dust will be released into the environment. The present invention aims at providing a suction device in which the collector unit releases substantially no dust particles and is characterized in that the collector unit comprises a vessel, under operational conditions at least partially filled with a liquid, and that an end of the suction tube that is connected to the collector unit ends in the liquid. The dust sucked up is collected in the liquid, normally water, and is passivated by that liquid. In the liquid the dust particles precipitate and the deposit thus obtained can be easily removed together with the liquid, therewith excluding the possibility that dust particles are released into the atmosphere. A favourable embodiment of the invention is characterized in that at least one grid is placed in the liquid and that under operational conditions the suction tube ends underneath the grid. At the at least one grid the air bubbles break up into finer bubbles while passing, which results in a still better washing out of the dust enclosed in the air bubbles. A further favourable embodiment that significantly simplifies the cleaning of the suction device is characterized in that a part of the suction tube located within the vessel and the at least one grid are detachably mounted. Preferably, the vessel is provided with a detachable collecting tank, thus enabling an efficient removal of the collected dust particles. In a favourable realization, the suction tube ends under operational conditions above the collecting tank, such that sucked-up air does not stir up the dust already collected. A further favourable embodiment of the inventive suction device is characterized in that the vessel is provided with an exhaust opening, situated above the liquid. With an opening located well above the liquid, the escape of small droplets of liquid in which dust may be included is substantially prevented. A favourable embodiment in which the possibility of small droplets escaping from the vessel is still further reduced is characterized in that the exhaust opening is provided with a drop-collecting filter. With the inventive suction device it is of importance that the liquid level does not rise too much due to the dust collected during its use. If the liquid level becomes too high this may negatively influence the suction power and it may increase the chance of liquid droplets escaping via the exhaust opening. A further favourable embodiment of the inventive suction device is therefore characterized in that the vessel is provided with a level detector or with overflow means for the liquid. The suction means can be inserted in the suction tube or they can be connected to the exhaust opening. The advantage of connecting the suction means to the exhaust opening is that they will suck up clean air and that they consequently will not get dirty. The disadvantage is that the construction of the vessel and the various sealings will be more complicated and expensive. The disadvantage of inserting the suction means in the suction tube is that they suck up polluted air and that a regular maintenance will be necessary. A favourable embodiment according to a further aspect of the invention which substantially obviates this disadvantage is characterized in that the suction means comprise a venturi, inserted in the suction tube, to which compressed air can be fed. The invention also relates to a grinding apparatus, sanding apparatus, milling apparatus or sawing apparatus, provided with a suction apparatus as described above. The equipment mentioned above will in general be powered by compressed air, at least for professional purposes. This compressed air can also be used then for generating the suction power by feeding it to a venturi. The invention will now be explained in more detail with reference to the following figures, in which: Fig. 1 represents a first possible embodiment of an industrial type of suction device; Fig. 2 represents a second possibleembodiment of an industrial type of suction device; Fig. 3A represents a first possible embodiment of a venturi; Fig. 3B represents a second possible embodiment of a venturi; Fig. 4 represents a possible embodiment of a domestic appliance type of suction device. Fig. 5 represents a possible embodiment of a drop collector. Fig. 1 represents a first possible embodiment of an industrial type of suction device, in which a vessel 1 made of for example a synthetic material is provided with an air pump 2, for example a centrifugal pump, which draws air via a suction tube 3 from a cap 4 located around a grinding disk 5, well known in the art. The drawn in air is polluted with for example quartz particles that are set free during grinding activities. Air pump 2 blows this air, via a tube 6, into vessel 1, which vessel 1 is filled with water 7. The air escapes from tube 6 as large bubbles 8 which ascend in water 7 and thereby pass through a grid 9, which grid 9 divides the air bubbles into smaller bubbles 10 and at the same time washes out the dust. The bubbles 10 then leave the liquid and are released from vessel 1 via a grid 11. The dust sinks to the bottom and ends up in a collecting tank 12, which is detachably placed in vessel 1. Before collecting tank 12 can be taken out, a cover 13 is removed from vessel 1 and grid 9 and the internal part of tube 6 are taken out. In order to support grid 9, collecting tank 12 is provided with two brackets 14. Moreover, the brackets 14 may be used for lifting collecting tank 13 out of vessel 1 when it is full. Grid 9 may further be provided with a hole for letting pass tube 6. In order to determine if collecting tank 12 is full, vessel 1 can be provided with an exhaust tube 15 or with a sensor. For activities during which large amounts of dust are released, for example during the milling of slots in lime containing walls, it can be advantageous to place a stack of grids in vessel 1. Moreover it is useful to select the type of grid dependent upon the type of activity, in which case for coarse dust usually a coarse grid is utilized, with holes of for example 1 centimetre and for fine dust usually a fine grid is utilized or a stack of a few fine grids, with holes of 0,5 cm. The grids are preferably made of strip material and have a thickness of 1-3 cm for example. Fig. 2 represents a second possible embodiment of an industrial type of suction device, in which a venturi 16 is located between suction tube 3 and tube 6. A suction effect is obtained, as is well known in the art, by feeding compressed air to a nozzle 17, schematically shown in the figure. The operation of the apparatus is further completely analogous to the apparatus as explained with reference to Fig. 1, but the advantage is that an actual pump is absent, which makes the apparatus more reliable and which reduces the necessary maintenance, especially if aggressive dust is to be removed, like quartz particles. The embodiments as shown in Fig. 1 and Fig. 2 can be realized in any size, dependent upon the type of application. For a painter using the apparatus during a sanding operation for example, the apparatus can be chosen much smaller than for a person gritting an object. Fig. 3A represents a first possible embodiment of a venturi 16, in which a centrally located nozzle 17 blows compressed air, supplied via a connection 18, into the direction of tube 6. Preferably, a restriction 19 is made near nozzle 17, which restriction may significantly increase the pump capacity. Fig. 3B represents a second possible embodiment of a venturi 16, in which an annular opening 20, placed near a restriction 19 blows compressed air, supplied via a connection 21, into the direction of tube 6. The advantage is that in the second embodiment the venturi substantially never gets obstructed, because the nozzle located in the centre is absent. Fig. 4 represents a possible embodiment of a domestic appliance type of suction device, also provided with a vessel 1 and an air pump 2, which air pump 2 draws air via a suction tube 3 and blows the air via a tube 6 into the water 7, with which vessel 1 is partially filled. Vessel 1 is provided with a first grid 9 with relatively large openings, for example 1 cm. in diameter and a second grid 22 with relatively small openings, for example 0,5 cm. In this way the air bubbles leaving tube 6 are subdivided into very fine bubbles, leading to a complete washing out of dust particles present in the air. In order to check the water level in vessel 1, vessel 1 is provided with a transparent part 23, as such forming a level gauge. The water level should on one hand be well above second grid 22 and on the other hand be not to high, because water could leak then via tube 6 to pump 2. In this embodiment cover 24 is provided with a drop-collecting filter, because in a home environment it would be unacceptable if water contaminated with dust would escape from the vacuum cleaner. The embodiment shown can easily be emptied by taking of lid 24 and by pouring the contents of vessel 1 into a sink. After that, fresh tap water can be poured in until the water level is seen in transparent part 23. Obviously, the suction device is very well suited for collecting dust, but also water can be sucked up. Moreover, pump 2 can be replaced by a venturi in this embodiment too, at least if compressed air is available. Fig. 5 schematically represents a cross section of a possible embodiment of a drop collector 25, as shown in Fig. 4 in the part AA' in cover 24 of vessel 1. Drop collector 25 consists of an annular support structure, forming the actual cover 24, in which a stack of plates 26 is mounted, for example glued. The plates each have a zigzag profile, which inevitably causes water droplets in the passing air to hit a plate. In this manner the droplets are effectively intercepted. Due to gravity, the collected water flows back into vessel 1 and washes out the dust particles that are possibly caught in drop collector 25.

Claims: Claims 1. Suction apparatus for sucking up and collecting dust particles, comprising a suction tube, suction means and a collector unit connected to the suction tube, characterized in that the collector unit comprises a vessel, under operational conditions at least partially filled with a liquid, and that an end of the suction tube that is connected to the collector unit ends in the liquid. 2. Suction apparatus according to claim 1, characterized in that at least one grid is placed in the liquid and that under operational conditions the suction tube ends underneath the grid. 3. Suction apparatus according to claim 2, characterized in that a part of the suction tube located within the vessel and the at least one grid are detachably mounted. 4. Suction apparatus according to claim 3, characterized in that the vessel is provided with a detachable collecting tank. 5. Suction apparatus according to claim 4, characterized in that the suction tube ends under operational conditions above the collecting tank. 6. Suction apparatus according to one of the previous claims, characterized in that the vessel is provided with an exhaust opening, situated above the liquid. 7. Suction apparatus according to claim 6, characterized in that the exhaust opening is provided with a drop- collecting filter. 8. Suction apparatus according to one of the previous claims, characterized in that the vessel is provided with a level detector or with overflow means for the liquid. 9. Suction apparatus according to one of the previous claims, characterized in that the suction means comprise a venturi, inserted in the suction tube, to which compressed air can be fed. 10. Grinding apparatus, sanding apparatus, milling apparatus or sawing apparatus, provided with a suction apparatus according to one of the previous claims.

Inventors: LEISTRA-DROOGSMA SIEUWKE, LEISTRA-DROOGSMA, SIEUWKE
Applicants: LEISTRA DROOGSMA SIEUWKE, LEISTRA-DROOGSMA, SIEUWKE
Application year: 2000
Main classification: A47L5
IPC codes: A47L5, A47L9, B23Q11, B24B5, B24B55