Cyclonic separating apparatus

ES 2 201 416 T3

DESCRIPTION

Cyclonic separating apparatus.

The invention relates to cyclonic separator apparatuses, and in particular but not exclusively to cyclonic vacuum cleaners.

There is a continuing demand for consumer goods to be compact, require minimal maintenance, and achieve maximum performance. The vacuum cleaner industry is no exception to this. However, it is also desirable that the cross-sectional area of ​​the air stream path within a vacuum cleaner be maintained at or above a specified minimum value. For cyclonic vacuums, which are currently very popular in the UK and other countries, a typical minimum airflow path cross-sectional area is between 500mm² and 1000 mm² , depending on the specific dimensions and functional characteristics of each machine. Maintaining a cross-sectional area within this range of values ​​does not pose any problem in most parts of the aspirator, but the tangential entry into the cyclone and the path of the air stream immediately before it constitutes a problem. part of the machine in which the fact of keeping the minimum area can affect the external dimensions of the machine. This can also cause the length of the air stream path to be extended beyond what would otherwise be desirable. An example of a cyclone vacuum cleaner is illustrated in EP 0 557 096.

Attempts have been made to "style" cyclonic vacuums. However, an adequate cross-sectional area should be provided immediately prior to tangential entry to allow the path of the air stream, passing outside the outer diameter of the cyclone prior to tangential entry, to maintain its minimum clearance area. cross section. This prevents any reduction in the radial dimension of the machine, which might have been otherwise desirable, or introduces an annoying and unsightly bulge or bulge into the apparatus. The problem is particularly aggravated in the area of ​​the entrance to the inner cyclone in vacuum cleaners that incorporate two concentric cyclones. Another disadvantage of the well-known tangential inlets inside cyclone aspirators and other separators is that which lies in the fact that at least part of the air stream entering the cyclone will be considerably distanced from the cyclone wall, and the particles that are dragged in that part of the air stream will need to reach the wall and be separated for a longer time than is desirable. In addition, the need to convert an airflow that previously travels helically along an annular path into a generally linear airflow immediately before the interior cyclone requires providing a length of duct or conduit that is sufficient to achieve the change. , said conduit or conduit being commonly called a transfer opening. Losses due to friction occur in such conduits. It would therefore be generally advantageous to avoid including the transfer opening in order to reduce the outer dimensions of the apparatus, and also to reduce the final length of the air stream path, and thereby reduce losses due to friction. It would also be advantageous if more of the air stream were introduced closer to the cyclone wall compared to what is currently possible. These principles are also applicable to cyclonic separators that are not aspirators.

US 3,969,096 describes a cyclone separator which is for separating solid particles in suspension from the exhaust gases of internal combustion engines and in which the separator has multiple vane gas inlets. US 3,853,518 describes an air filter for the intake system of an engine with multiple intake passages.

It is an object of the invention to provide a cyclone separator apparatus that is capable of maintaining a minimum cross-sectional area of ​​the fluid flow while minimizing its outer dimensions. It is a further objective of the present invention to provide a vacuum cleaner that is more compact than other vacuum cleaners. A further objective is to provide a cyclone separator apparatus which has an increased efficiency and / or which has less losses than similar known separator apparatus. A further objective is to provide a cyclone separator apparatus in which the particles that are entrained in the fluid stream entering the cyclone are closer to the cyclone wall than in known apparatuses.

The invention provides a cyclone separator apparatus as claimed in claim 1. Additional advantageous features are set forth in the dependent claims. The invention also provides a vacuum cleaner as described in claim 11.

By providing two or more entry points into the cyclone surface, the entry is effectively extended within a greater proportion of the cyclone surface circumference. If two entry points are provided, the radial dimension that is necessary to achieve the minimum cross-sectional area of ​​the air flow can be reduced by one half without affecting the axial dimension of the entry points. If ten entry points are foreseen, the required radial dimension is only one tenth of what was previously required. The transfer opening that was previously necessary can be dispensed with, and a considerable reduction in the width of the machine can be achieved. The fluid flow entering the cyclone separator apparatus is much closer to the cyclone wall than in known systems and is also less turbulent than that entering a similar apparatus having only one entry point. Preferably, the entry points are equidistant about the longitudinal axis of the cyclone. This axially symmetrical arrangement stabilizes the flow in the cyclone and improves separation performance.

Each entry point consists of a longitudinal slit to direct the fluid into the cyclone in a tangential manner. A vane is provided to fluidly direct fluid through each slit. This type of configuration is easy to manufacture by molding from plastic, and is therefore inexpensive and maintenance-free. The system has no need for a spiral-type transfer inlet or opening when the apparatus is part of a vacuum cleaner that has two cyclone separators,

ES 2 201 416 T3, thereby reducing the length of the path of the air stream between the spacers, and also reducing power losses due to friction. The air flow entering the cyclone is also more axially symmetrical than in separators that have a single tangential inlet.

An embodiment of the invention is described below by way of example only and with reference to the accompanying drawings, in which:

Figure 1 is a schematic side view in section of a cyclone separator apparatus according to the state of the art;

Figure 2 is a schematic sectional side view of a cyclone separator apparatus incorporating the present invention; and Figures 3a and 3b are respectively perspective and plan views of a component of the apparatus of Figure 2 where the details of the invention can be clearly appreciated according to the embodiment thereof.

Figure 1 schematically illustrates a known cyclone separator apparatus of the type that is suitable for use in cyclonic aspirators. For the sake of clarity only the separating apparatus is illustrated in Figure 1. When the apparatus forms part of a vacuum cleaner, at least one dirty air inlet will be arranged before the illustrated separator apparatus, and a clean air outlet will be arranged after said separator apparatus. There will normally be provided after the separating apparatus but before the clean air outlet an assembly that constitutes a motor or fan that is capable of sucking in a flow of air from the dirty air inlet, passing it through the separating apparatus and leading it to the outlet. of clean air. The assembly that constitutes a motor or fan will normally be located within the path of the air stream in order to make use of the air stream to cool the motor. However, these details do not affect the present invention, and therefore will not be written in more detail here.

As illustrated, the known separator apparatus 10 incorporates an outer cyclone 12 and an inner cyclone 14. Construction details are set forth below.

The cyclone separator apparatus 10 comprises an upper annular plate 16. A cylindrical vortex seeker 18, made in the form of a cylindrical tube, passes through the annular plate 16, projecting both into the cyclone separator apparatus 10 and upward beyond the ring plate 16. The cylindrical vortex finder 18 includes at its upper end means for connecting the cyclone separator apparatus 10 to the subsequent air stream path of the apparatus, although the connecting means are not illustrated for the sake of clarity. The cylindrical vortex finder 18 protrudes into the cyclone separator apparatus 10 over a distance that is equal to about 0.9 times the outer diameter of the annular plate 16.

The inner cyclone 14 depends on the annular plate 16. The inner cyclone 14 consists of an upper cylindrical part 14a and a frusto-conical part 14b. The upper cylindrical part 14a ends at a level that is located higher than the lower end of the cylindrical vortex seeker 18. The frusto-conical part 14b of the inner cyclone 14 runs conically downward and ends in a conical mouth 20. The diameter of the conical mouth 20 is not greater than the diameter of the cylindrical seeker of the vortex 18.

A cover 24 is positioned radially outward from the inner cyclone 14. The cover 24 has an outer annular rim 24a, a frusto-conical portion 24b, a perforated cylindrical portion 24c, and an inner annular rim 24d. The inner annular rim 24d is sealed to the frusto-conical portion 14b of the inner cyclone 14. The perforated cylindrical portion 24c runs upwardly towards the annular plate 16 from the outer edge of the inner annular rim 24d. The frusto-conical part 24b is substantially parallel to the frusto-conical part 14b of the inner cyclone 14 but is spaced therefrom in such a way that an annular passage is formed between the two frusto-conical parts 14b and 24b. The outer annular rim 24a runs from the upper edge of the frusto-conical portion 24b of the cover 24 and ends in registration with the outer edge of the annular plate 16.

A cylindrical reservoir 26 hangs from the annular plate 16. The cylindrical reservoir 26 is sealed to the outer edge of the annular plate 16. The outer annular rim 24a of the cover also forms a seal against the wall of the cylindrical reservoir 26. An annular chamber 22 is thereby formed radially outward of the frusto-conical part 14b of the cover 14, and said annular chamber is delimited on the other three sides by the cylindrical reservoir 26, the outer annular rim 24a of the cover 24 and a annular sealing flap 23. The annular passageway between the two frusto-conical parts 14b and 24b forms an inlet to the annular chamber 22. A transfer opening 27 that extends beyond the cylindrical reservoir 26 constitutes an outlet from the annular chamber 22. The transfer opening 27 constitutes a tangential air inlet in the wall of the upper cylindrical part 14a, so that the air entering the inner cyclone 14 flows tangentially towards the wall of the upper cylindrical part 14a. The transfer opening 27 must have a cross-sectional area that is large enough to ensure that the free circulation of air within the apparatus 10 is not impeded.

The base 28 of the cylindrical tank 26 forms an integral part of the cylindrical tank 26, or it can be removable to allow emptying. Surfaces 30 extend between a part of the cylindrical reservoir 26 close to the base 28 and a part of the frusto-conical part 14b of the inner cyclone 14 located slightly higher than the conical mouth 20. Surfaces 30 divide the interior of the cylindrical reservoir forming a first dust collection zone 32 for the first outer cyclone or cyclone 12 and a second dust collection zone 34 for the second inner cyclone or cyclone 14.

A front tangential air inlet 40 is arranged in the wall of the cylindrical reservoir 26 immediately below the outer annular rim 24a of the cover 24. The front tangential air inlet 40 constitutes an inlet to the outer cyclone 12 to allow the introduction of air flow between the wall of the cylindrical tank 26 and the frusto-conical part 24b of the cover 24. The front tangential air inlet 40 has a lower edge 42 that is positioned upward relative to the upper edge of the perforated cylindrical portion 24c of the cover 24. The cross-sectional area of ​​the front tangential air inlet immediately before the apparatus ci3 separator

ES 2 201 416 T3 clone is essentially 800 mm² or it has another suitable value, depending on the specific characteristics of the machine in which the apparatus is used.

The operation of the cyclone separator apparatus 10 described above will now be described. An air stream in which dirt and dust are entrained is introduced at relatively high speed into the outer cyclone 12 through the forward tangential air inlet 40. Air circulates helically around the outer wall of cylindrical reservoir 26 and travels helically downward causing dirt and debris to separate from the air flow due to centrifugal forces. The air then moves inwards and upwards over the surfaces 30 and passes through the perforations that are made in the perforated cylindrical part 24c of the cover 24, leaving a considerable amount of dirt and debris in the first zone 32 dust collection. The air then passes through the annular passage that is formed between the frustoconical part 24b of the cover 24 and the frustoconical part 14b of the inner cyclone 14. The air passes into the annular chamber 22, and from there and through the transfer opening 27 to the tangential air inlet to the internal cyclone 14, and the helical displacement of the air flow accelerating downward through the frustoconical part 14b makes very high speeds are reached and dust and dirt particles are separated from the air flow. As the air passes through the conical mouth 20 into the second dust collection zone 34, additional dust and dirt particles that are still entrained in the air flow are separated and collected, while the clean air returns through from the conical mouth 20 and exits the cyclone separator apparatus 10 through the cylindrical vortex seeker 18.

It will be appreciated from the above description that the dimensions of the cyclone separator apparatus 10 cannot be greatly reduced, in particular as regards the diameter of the apparatus in the region of the upper end of the inner cyclone 14. Transfer opening 27 forms the only inlet to inner cyclone 14, and consequently the cross-sectional area of ​​the air stream path at and immediately prior to this point must be kept at a specific minimum value or at a minimum. level higher than it, being for example between 500 mm² and 1000 mm² . If the diameter of the cyclone separator apparatus 10 were reduced at this point, an unacceptable elongation of the apparatus 10 in the direction of the longitudinal axis thereof would be necessary.

It will also be clear from Figure 1 that a part of the air flow entering each cyclone 12, 14 is considerably spaced from the wall 26, 14b thereof. The greater the initial distance of a entrained particle to the corresponding wall, the greater the amount of time that is required for the separation of that particle to take place. Consequently, the particles that are entrained in the air flow entering each cyclone 12, 14 to the right of each entrance 40, 27 as seen in Figure 1 will take a considerable period of time to be separated, and may even are not separated at all.

As will also be appreciated from Figure 1, the length of the air stream path between the outer cyclone 12 and the inner cyclone 14 is considerable. The air that moves up through the annular passage that is formed between the frustoconical part 24b of the cover 24 and the frustoconical part 14b of the inner cyclone 14 enters the annular chamber 22 and is then forced to circulate around the annular chamber 22 before entering the inner cyclone 14 through the transfer opening 27. Frictional losses due to the passage of air around the annular chamber 22 can be considerable.

An embodiment of the invention is illustrated in Figures 2 and 3. Figure 2 is a schematic sectional side view of the cyclone separator apparatus 110 that is similar to that illustrated in Figure 1, whereby a comparison can be made between the invention and the state of the art. Many of the components of apparatus 110 that is illustrated in Figure 2 are substantially the same as the corresponding components that are illustrated in Figure 1. The essential differences between them are described below.

The most important difference lies in how the path of the air stream is carried out by which the air is transferred between the outer cyclone 112 and the inner cyclone 114. In the embodiment of the invention, the upper cylindrical portion 114a of the inner cyclone 114 has a plurality of entry points 152 that are spaced about the longitudinal axis of the apparatus 110 to allow air to pass through the annular passage that is formed between the frusto-conical portion 124b of the cover 124 and the frusto-conical portion 114b of the inner cyclone 114 pass directly to the inner cyclone 114 in a tangential manner. Details of how the upper cylindrical portion 114a is made will be described more fully later. However, the ability to pass air directly from the annular passageway to inner cyclone 114 eliminates the need for a spiral-type transfer inlet or opening that is part of the air stream path of the apparatus illustrated in Figure 1. Not only does it happen that the omission of the inlet makes it possible to reduce the radial dimension of the apparatus and simplify the construction of the apparatus as a whole, but the reduction of the length of the path of the air stream can also reduce the power losses due to the friction.

It will be appreciated from Figures 1 and 2 that as a result of the present invention the radial dimension of apparatus 110 may be reduced. Furthermore, in the apparatus illustrated in Figure 2 any rotational movement that is present in approaching air inner cyclone 114 is maintained rather than removed prior to entry. This improves the separation performance of the inner cyclone 114.

Before giving the detailed description of the upper cylindrical part 114a of the inner cyclone 114, the general mode of operation of the apparatus 110 which is illustrated in Figure 2 will be described. As already described above, the dirty air enters the outer cyclone. 112 through tangential air inlet 140. The dirty air circulates helically around the outer wall of the cylindrical reservoir 126 and travels helically downward causing dirt and debris to be separated from the air flow due to centrifugal forces. The air then moves inward and upward over the surfaces 130 and passes through the perforations that are made in the perforated cylindrical portion 124c of the cover 124. A considerable amount of dust remains in the first dust collection zone 132

ES 2 201 416 T3 amount of dirt and residue. The air flow then passes along the annular passage that is formed between the frusto-conical portion 124b and the frusto-conical portion 114b. The air flow enters the cylindrical passage 122 which is formed between the inner cyclone 114 and the top of the cylindrical reservoir 126. The air is then directed immediately, by means of blades 154, through those of a plurality of longitudinal slits 152 that are made in the upper cylindrical part 114a of the inner cyclone 114, and is directed tangentially into the inner cyclone 114. As described in connection with Figure 1, the air then circulates helically down the inner surface of the inner cyclone 114, and the helical motion of the air flow causes very high speeds to be reached and dust particles and particles are separated. dirt. As the air passes through the conical mouth 120 entering the second dust collection zone 134, the dust and dirt particles that were still entrained in the air flow are separated and collected, while the clean air returns through from the conical mouth 120 and exits the cyclone separator apparatus 110 through the cylindrical vortex seeker 118. As before, the cylindrical reservoir 126 may be made removable to allow the first and second dust collection zones 132, 134 to be emptied.

Figures 3a and 3b are respectively a perspective view and a plan view of the inner cyclone 114 which forms part of the apparatus 110 which is illustrated in Figure 2. The inner cyclone 114 has an upper cylindrical part 114a and a frusto-conical part 114b, the frusto-conical portion 114b incorporating a circular groove 114c to resiliently admit the inner edge of the inner annular rim 124d of the cover 124 illustrated in Figure 2.

The upper cylindrical portion 114a incorporates a plurality of helically offset parietal portions 150 that are equidistant in the upper cylindrical portion 114a. In the embodiment illustrated in Figure 3, ten parietal parts 150 are illustrated. However, the number of parietal parts 150 can be varied to suit needs. For example, a number of parietal parts as small as four or as large as twenty could be envisaged. Each parietal portion 150 is arranged such that its leading edge is further radially away from the longitudinal axis of the inner cyclone 114 than its trailing edge. Thus, each parietal portion 150 runs substantially helically. A longitudinal slit 152 is formed between the trailing edge of a first parietal portion and the leading edge of the subsequent parietal portion 150, viewed in the direction of air circulation. The total area of ​​the longitudinal slits 152 is not less than the specified minimum diameter of the air stream path of the apparatus 110. For example, when ten longitudinal slits 152 are provided and when the specified minimum flow cross-sectional area air is 800mm² , each longitudinal slit 152 should then have an effective cross-sectional area of ​​at least 80 mm² .

The leading and trailing edges of each parietal portion 150 are configured to minimize losses due to friction when an air flow passes through the parietal portions 150. As can be clearly seen from Figures 3a and 3b, each parietal portion is preferably in cross section streamlined paddle shape. Specifically, the leading edge of each parietal portion 150 is generally rounded, and the trailing edge of each parietal portion 150 is generally tapered.

An arcuate blade 154 is located on the radially outer face of each parietal portion 150. Each blade 154 has a lower portion 154a that begins generally at the intersection between the frusto-conical portion 114b and the upper cylindrical porti on 114a of the inner cyclone 114. The lower part 154a runs generally parallel to the longitudinal axis of the inner cyclone 114 and then joins the arcuate upper part 154b, which runs from the lower part 154a towards the leading edge of the corresponding parietal part 150.

Each blade 154 extends radially outward from the outer surface of the respective parietal portion 150 toward the top of the cylindrical reservoir 126, which is located radially outward of the inner cyclone 114. The blades 154 extend radially outward lo sufficient to contact cylindrical reservoir 126, and preferably vanes 154 are tightly in contact against cylindrical reservoir 126. However, it is not essential that contact is made with the cylindrical reservoir 126.

They may be provided in the form of a blind recess located in one of the parietal portions 150 locating means 160 to ensure that the inner cyclone 114 is correctly oriented with respect to the rest of the apparatus 110. However, the locating means 160 are not part of the invention set forth herein.

It will also be appreciated that the entire inner cyclone 114 which is illustrated in Figures 3a and 3b can be easily manufactured by injection of a plastic without undue difficulty. The inner cyclone 114 can therefore replace the inner cyclone 14 which is illustrated in Figure 1, with the consequent advantages consisting of a reduction in losses, a reduction in dimensions and a simplicity of construction. It will be appreciated that when used in the apparatus 110 which is illustrated in Figure 2 the inner cyclone 114 which is illustrated in Figures 3a and 3b the air passing through the annular passage which is formed between the frusto-conical portions 114b and 124b is directed immediately via vanes 154 through longitudinal slits 152 and onto the inner surface of inner cyclone 114. The length of the air stream path between the outer and inner cyclones is therefore minimized, and consequent reductions in frictional losses are then achieved. Furthermore, since the minimum cross-sectional area of ​​the air stream path can be maintained while the radial dimension of the apparatus as a whole can be reduced, the objective of providing a more compact aspirator can be achieved.

The flow in the inner cyclone 114 is also less turbulent due to the fact that the inlet openings are axially symmetrical, and this increases the separation efficiency of the cyclone.

An additional advantage of the system illustrated in Figures 2 and 3 is that all of the air entering the inner cyclone 114 is relatively close to the cyclone wall at the inlet. Since the time it takes for a particle to be separated from the air flow of 5

ES 2 201 416 T3 will depend on the initial distance of that particle from the wall, the separation of the particles from the air flow will be faster when the apparatus of the invention is used compared to other devices in which at least a part of the air flow enters the cyclone being further away from the wall.

The invention is not limited to the embodiment described above. Modifications and alterations that do not affect the principle of the invention will be obvious to a reader skilled in the art. For example, the vortex finder could be considerably shorter and does not necessarily have to protrude above the ring plate. The base of the cylindrical reservoir could be conical or frusto-conical, and other relative dimensions could be altered without thereby departing from the scope of the invention. As mentioned above, vanes that direct air into the longitudinal slits do not necessarily have to be included.

The principles of the invention can be applied to cyclonic separators that are intended for use in sectors other than vacuum cleaners and that are in fact intended to be used to separate particulates from fluid streams other than air.