Patent Grant
9005324
This application claims priority to EP Patent Application No. EP 11 184 819.8 filed Oct. 12, 2011, the contents thereof to be incorporated herein by reference in its entirety.
The present invention relates to a motor, fan and cyclonic separation apparatus arrangement. In particular, but not exclusively, the present invention relates to a motor, fan and cyclonic separation apparatus arrangement for use in vacuum cleaners.
Vacuum cleaners are well known for collecting dust and dirt, although wet-and-dry variants which can also collect liquids are known as well. Typically, vacuum cleaners are intended for use in a domestic environment, although they also find uses in other environments, such as worksites or in the garden. Generally, they are electrically powered and therefore comprise an electric motor and a fan connected to an output shaft of the motor, an inlet for dirty air, an outlet for clean air and a collection chamber for dust, dirt and possibly also liquids. Electrical power for the motor may be provided by a source of mains electricity, in which case the vacuum cleaner will further comprise an electrical power cable, by a removable and replaceable battery pack, or by one or more in-built rechargeable cells, in which case the vacuum cleaner will further comprise some means, such as a jack plug or electrical contacts, for connecting the vacuum cleaner to a recharging unit. When the vacuum cleaner is provided with electrical power from one of these sources, the electric motor drives the fan to draw dirty air along an air flow pathway in through the dirty air inlet, via the collection chamber to the clean air outlet. The fan is often a centrifugal fan, although it can be an impeller or a propeller.
Interposed at some point along the air flow pathway, there is also provided some means for separating out dust and dirt (and possibly also liquids) entrained with the dirty air and depositing these in the collection chamber. This dirt separation means may comprise a bag filter, one or more filters and/or a cyclonic separation apparatus.
In the event that the dirt separation means comprises a bag filter, dirty air, which has entered the vacuum cleaner via the dirty air inlet, passes through the bag filter. This filters out, and collects within the bag filter, dust and dirt entrained with the dirty air. The filtered material remains in the bag filter which lines the collection chamber. The clean air then passes to the other side of bag filter and through a grille in the collection chamber under the influence of the fan. The fan draws air in and expels it out, from where the air then passes to the clean air outlet of the vacuum cleaner.
There is always a small risk of dust and dirt passing through the bag filter and it is undesirable that it be allowed to pass through the fan and cause damage. To reduce this potential problem, there is often a fine filter located across the grille of the collection chamber to remove any fine dust and dirt particles remaining in the air flow after passage through the bag filter. This is commonly known as a pre-fan filter.
Occasionally, and in addition to any pre-fan filter, there is a high efficiency filter located downstream of the fan before the air flow leaves the vacuum cleaner. This is to remove any remaining extremely fine particulate matter which will not harm the fan or motor, but which may be harmful to the household environment. The term “filtering efficiency” is intended to relate to the relative size of particulate matter removed by a filter. For example, a high efficiency filter is able to remove smaller particulate matter from air flow than a low efficiency filter. A HEPA filter is a high efficiency filter which should be able to remove extremely fine particulate matter having a diameter of 0.3 micrometers (μm) and lower.
The purpose of the bag filter is to filter dust and dirt entrained in dirty air flow and to collect the filtered material within the bag filter. This progressively clogs the bag filter. The volumetric flow rate of air through the vacuum cleaner is progressively reduced and its ability to pick up dust and dirt diminishes correspondingly. Hence, the bag filter needs replacement before it becomes too full and before vacuum cleaner performance becomes unacceptable. The volume of the collection chamber must be sufficiently large to merit the cost of regular bag filter replacement.
An upright vacuum cleaner commonly has an upright main body with a dirt separating means, a motor and fan unit, a handle at the top and a pair of support wheels at the bottom. A cleaner head with a dirty air inlet facing the floor is pivotally mounted to the main body. A cylinder vacuum cleaner commonly has a cylindrical main body with a separating dirt means, a motor and fan unit and maneuverable support wheels underneath. A flexible hose with a cleaner head communicates with the main body. Bag filters are commonly used in upright and cylinder vacuum cleaners as separation means because their main body has sufficient internal space for the large collection chamber required to accommodate the bag filter.
In the event that the dirt separation means comprises a filter, dirty air, which has entered the vacuum cleaner via the dirty air inlet, passes through the filter. This filters out dust and dirt entrained with the dirty air and the filtered material remains in the collection chamber on the upstream side of the filter. Sometimes the filter is supplemented by a sponge to absorb any liquids entrained in the dirty air flow. The clean air then passes to the other side of filter under the influence of the fan, and from the fan the air then passes to the clean air outlet of the vacuum cleaner.
Filtered material accumulates around, and progressively clogs, the filter. The volumetric flow rate of air through the vacuum cleaner is progressively reduced and its ability to pick up dust and dirt diminishes correspondingly. Hence, the collection chamber needs regular emptying and the filter needs frequent cleaning to mitigate against this effect. Sometimes, the vacuum cleaner has a filter cleaning mechanism. Alternatively, the filter needs to be removable for cleaning with a brush, or in a dish washer, for example.
Hand-holdable vacuum cleaners, as their name would suggest, are compact and lightweight and are intended to perform light, or quick, cleaning duties around a household. Typically, hand-holdable vacuum cleaners are battery-powered to be easily portable.
An example of a hand-holdable vacuum cleaner having the conventional motor, fan and filter arrangement is described in European patent publication no. EP 1 752 076 A, also in the name of the present applicant. This vacuum cleaner has dirty air inlet at one end of a dirty air duct leading to a collection chamber with a filter. The collection chamber is generally cylindrical and is arranged transverse the body of the vacuum cleaner. The dirty air duct is rotatable, with the collection chamber, in relation to the body. The dirty air duct may be adjusted to access awkward spaces while the vacuum cleaner is held comfortably by a user.
In the event that the dirt separation means comprises cyclonic separation apparatus, dirty air, which has entered the vacuum cleaner via the dirty air inlet, passes through the cyclonic separation apparatus having one or more cyclones. A cyclone is a hollow cylindrical chamber, conical chamber, frustro-conical chamber or combination of two or more such types of chamber. The cyclone may have a vortex finder part way, or all way, along its internal length. The vortex finder is commonly a hollow cylinder and it has a smaller external diameter than the internal diameter of the cyclone.
Dirty air enters via a tangentially arranged air inlet port and swirls around the cyclone in an outer vortex. Centrifugal forces move the dust and dirt outwards to strike the side of the cyclone unit and separate it from the air flow. The dust and dirt is deposited at the bottom of the cyclone and into a collection chamber below. An inner vortex of cleaned air then rises back up the cyclone. The role of a vortex finder is to gather and direct the cleaned air through an air outlet port at the top of the cyclone. As an alternative to a vortex finder, the cyclone may have an inner cylindrical air permeable wall providing the cleaned air with a path from the cyclone. From the cyclone the cleaned air passes, under the influence of the fan, to the clean air outlet of the vacuum cleaner.
As with a bag filter, a vacuum cleaner with a cyclonic separation apparatus may have a pre-fan filter to protect the fan and motor, especially if the air flow is used to cool the motor. Nevertheless, volumetric flow rate of air through the vacuum cleaner remains virtually constant as separated material accumulates in the collection chamber. Thus, an attraction of cyclonic separation apparatus in a vacuum cleaner is a consistent ability to pick up dust and dirt. Another attraction is that the cost of regular bag filter replacement is avoided.
An example of an upright vacuum cleaner having a motor, fan and cyclonic separation apparatus is described in European patent publication no. EP 0 042 723 A. This cyclonic separation apparatus is divided into a first cyclonic separating unit with a cyclone formed by an annular chamber and a second cyclonic separating unit with a generally frustro-conical cyclone. The first cyclonic separating unit is ducted in series with the second cyclonic separating unit. Air flows sequentially through the first, and then the second, cyclonic separating units. The frustro-conical cyclone has a smaller diameter than the annular chamber within which the frustro-conical cyclone is partially nested. Separated material from both cyclonic separating units collects in the cylindrical collection chamber formed at the bottom of the annular chamber.
The term “separation efficiency” is used in the same way as filtering efficiency and it relates to the relative ability of a cyclonic separation apparatus to remove small particulate matter. For example, a high efficiency cyclonic unit can remove smaller particulate matter from air flow than a low efficiency cyclonic separating unit. Factors that influence separation efficiency can include the size and inclination of the dirty air inlet of a cyclone, size of the clean air outlet of a cyclone, the angle of taper of any frustro-conical portion of a cyclone, and the diameter and the length of a cyclone. Small diameter cyclones commonly have a higher separation efficiency than large diameter cyclones, although other factors listed above can have an equally important influence.
The first cyclonic separating unit of EP 0 042 723 A has a lower separating efficiency than the second cyclonic separating unit. The first cyclonic separating unit separates larger dust and dirt from the air flow. This leaves the second cyclonic separating unit to function in its optimum conditions with comparatively clean air flow and separate out smaller dust and dirt.
A hand-holdable vacuum cleaner having a motor, fan and cyclonic separation apparatus is described in United Kingdom patent publication no. GB 2 440 110 A. This cyclonic separation apparatus is smaller than that of EP 0 042 723 A in order to be used in a hand-holdable vacuum. It is divided into a first cyclonic separating unit and a second cyclonic separating unit located downstream of the first cyclonic separating unit. The separating efficiency of the first cyclonic separating unit is lower than that of the second cyclonic separating unit.
The second cyclonic separating unit of GB 2 440 110 A comprises six cyclones arranged in a circular array protruding into an annular chamber. The space within this circular array of cyclones is used to duct air flow from the annular chamber to the air inlet ports of the cyclones.
It is an object of the present invention to provide a motor, fan and cyclonic separation apparatus arrangement which makes more efficient use of the space it occupies. This is particularly desirable in a vacuum cleaner, where the efficient use of space is of great importance and any wasted space will necessarily add to the overall size and weight of the vacuum cleaner, without giving any counteracting benefit. It is also an object of the present invention to provide a motor, fan and cyclonic separation apparatus arrangement particularly suitable for use in a compact or hand-holdable vacuum cleaner. A further object of the invention is to provide a vacuum cleaner comprising such a motor, fan and cyclonic separation apparatus arrangement.
Accordingly, in a first aspect, the present invention provides a motor, fan and cyclonic separation apparatus arrangement for a vacuum cleaner, the arrangement comprising: a motor coupled to a fan for generating air flow; and a cyclonic separation apparatus located in a path of the air flow generated by the fan, wherein the cyclonic separation apparatus comprises a plurality of cyclones each with an air inlet port and an air outlet port, wherein the cyclones are arranged in a generally circular array about a central axis of the cyclonic separation apparatus, and a cooling air flow path, wherein the motor is nested within the generally circular array of cyclones and wherein the motor is located in the cooling air flow path.
The present invention makes more efficient use of the space which naturally exists within the circular array of cyclones. A motor is nested amongst the cyclones instead of the motor occupying space elsewhere. The motor is cooled for operation in this confined space. The motor drives the fan which generates air flow through the cyclonic separation apparatus. Even with the motor nested amongst the cyclones there remains gaps between the cyclones and the cylindrical body of the motor which can be put to other uses, like, for example, ducting air flow to the air inlet ports of the cyclones. The resulting arrangement is compact and, as a result, makes a vacuum cleaner more compact as it need not find space for the motor elsewhere in the body of the vacuum cleaner. This provides more versatile vacuum cleaner design options. Also, the close proximity of the motor and the fan to the cyclonic separation apparatus may reduce energy loss by reducing the overall length of the air flow path.
Preferably, the plurality of cyclones is at least eight cyclones arranged in a generally circular array having an inner annulus and an outer annulus, wherein a diameter of the inner annulus is at least 30 percent of a diameter of the outer annulus. This may provide enough cyclones of a suitable diameter to perform efficient vacuum cleaning and yet provide enough space within the circular array to accommodate a suitably sized motor to drive the fan to generate sufficient air flow.
Preferably, the central axis of the cyclonic separation apparatus passes through the motor. As such, the motor is located near, or at, the middle of the circular array of cyclones so that the motor may occupy less space.
Preferably, the circular array of cyclones is axially symmetric and the motor is concentric with the central axis. This provides a more compact cyclone separating apparatus as the components are arranged evenly about the central axis.
Preferably, the motor is coupled to supplementary means for augmenting cooling air flow through the cooling air flow path. The motor is used to assist its own cooling. Cooling air flow may increase through the cooling air flow path just when the motor is working hardest and cooling is needed most.
Preferably, the cyclonic separation apparatus comprises: a first cyclonic separating unit comprising a hollow substantially cylindrical dirt container concentric with the central axis of the cyclonic separation apparatus, and an air inlet port arranged tangentially through a side of the dirt container, and a second cyclonic separating unit comprising the plurality of cyclones, wherein the second cyclonic separating unit receives air flow downstream from the first cyclonic separating unit. A dual cyclonic separation apparatus improves cleaning of dirty air by sharing separation of different particulate matter sizes between cyclonic separating units of varying separation efficiencies.
Preferably, the motor and the second cyclonic separating unit are located in the dirt container. This provides a more compact arrangement in an axial direction.
Preferably, an outer diameter of the motor is at least 15 percent of an outer diameter of the dirt container. This provides a large enough dirt container to separate and collect larger dirt particles and yet proved enough space for the circular array of cyclones and have a suitably sized motor to drive the fan to generate sufficient air flow.
Preferably, the second cyclonic separating unit has a higher separation efficiency than the first cyclonic separating unit. The large particulate matter is separated in the dirt container initially, leaving the high efficiency cyclones to separate the more difficult small particulate matter.
Preferably, the cyclonic separation apparatus comprises an intermediate wall arranged within the dirt container, wherein the intermediate wall surrounds the air inlet ports of the cyclones. The intermediate wall shields the air inlet ports from the dirty air flow vortex within the cylindrical dirt container. This helps to avoid re-entrainment of dirt in the air flow destined for the cyclones.
Preferably, the intermediate wall defines a chamber with an air permeable wall arranged as an air outlet from the first cyclonic separating unit and wherein the second cyclonic separating unit receives air flow downstream from the first cyclonic separating unit via the chamber. Partially cleaned air flows in a gentle inner vortex back up and around intermediate wall before passing through the air permeable wall to the air inlet ports. The air permeable wall provides the benefit of an extra dirt filtration stage and deposits filtered dirt in the dirt container. The chamber allows air flow to distribute itself through the gaps between the cyclones and the motor and on to the air inlet ports of the cyclones.
Preferably, the first and second cyclonic separating units are arranged to deposit material separated from air flow in a longitudinal end of the dirt container, wherein the cyclonic separation apparatus comprises a funnel arranged to collect material separated by the cyclones, wherein the funnel has a conical wall tapered towards the dirt container to deposit material separated by the cyclones in an area of the dirt container isolated by the funnel from air flow in the first cyclonic separating unit. Small and large separated dirt is collected and emptied together, thus making the cyclonic separation apparatus more convenient. The tapered funnel deposits small dirt particles in a relatively smaller area of the dirt container than the larger dirt particles which take more space. This helps to prolong the time between emptying the dirt container by balancing the filling rate of the dirt container.
Preferably, each cyclone comprises: a cyclone body with a hollow generally cylindrical portion, a hollow generally frustro-conical portion depending from the cylindrical portion and a longitudinal axis; a vortex finder arranged inside the cylindrical portion; a discharge nozzle arranged at a longitudinal end of the frustro-conical portion; the air inlet port arranged tangentially through a side of the cylindrical portion; and the air outlet port through the vortex finder and the opposite end of the cylindrical portion. The plurality of cyclones, in parallel combination, sustain the same air flow as the dirt container and yet they have a higher separation efficiency than the dirt container. The vortex of air flowing towards the discharge nozzle of each cyclone accelerates as the cyclone body's diameter decreases to separate ever smaller dirt particles and to increase separation efficiency.
Preferably, the arrangement comprises a pre-fan filter located in the path of the air flow downstream of the cyclones and upstream of the fan, wherein the pre-fan filter has an annular cross-sectional profile normal to the central axis of the cyclonic separation apparatus and wherein the pre-fan filter is arranged upon the air outlet ports of the cyclones. This is a compact use of space. It reduces energy loss by reducing the overall length of the air flow path and, in particular, the air flow path from the cyclones to the pre-fan filter. Also, location of the pre-fan filter upon the air outlet ports may muffle high frequency sounds generated by Helmholtz resonance as air flow through the air outlet ports.
Preferably, a portion of the motor is nested within the annular pre-fan filter. This makes the arrangement more compact by taking up space within the pre-fan filter.
In a second aspect, the present invention provides a vacuum cleaner comprising the motor, fan and the cyclonic separation apparatus arrangement according to the first aspect. The vacuum cleaner may be a more compact design because it benefits from the compact design of the motor, fan and cyclonic separation apparatus arrangement of the first aspect and it need not accommodate the motor within its body housing.
Preferably, the vacuum cleaner is a battery-powered hand-holdable vacuum cleaner comprising a detachable and/or rechargeable battery. This provides a vacuum cleaner that may be readily portable and convenient to use without need to find a mains electrical supply.
Preferably, the cyclonic separation apparatus comprises at least one protruding lip arranged to impede movement of separated material from said longitudinal end of the dirt container. This helps to avoid re-entrainment of separated dirt into the air flow destined for the cyclones. Preferably, the dirt container comprises a generally cylindrical exterior wall and a generally circular end wall at said longitudinal end of the exterior wall, wherein the air inlet port is arranged tangentially through the exterior wall and wherein the end wall is detachably connected to the exterior wall. The detachable end wall facilitates emptying of dirt in the dirt container. Preferably, the end wall is hingedly connected to the exterior wall so that the end wall is not mislaid after opening. Preferably, the plane of the discharge nozzle is inclined with respect to the longitudinal axis of the cyclone body. This helps to avoid separated material from re-entering the discharge nozzle. Preferably, the longitudinal axis of each cyclone is in line with the central axis of the cyclonic separation apparatus. Preferably, the longitudinal axis of each cyclone is parallel with the central axis of the cyclonic separation apparatus. Preferably, the fan is a centrifugal fan having a tangential output. Preferably, the plurality of cyclones is no more than sixteen cyclones. More preferably the plurality of cyclones is no more than fourteen cyclones. Preferably, the plurality of cyclones is no fewer than eight cyclones. More preferably the plurality of cyclones is no fewer than ten cyclones. Most preferably, the plurality of cyclones is twelve cyclones. Preferably, the ratio of the outer diameter of the dirt container to the outer diameter of each cyclone is no greater than 28:3. More preferably the ratio of the outer diameter of the dirt container to the outer diameter of each cyclone is no greater than 24:3. Preferably, the ratio of the outer diameter of the dirt container to the outer diameter of each cyclone is no less than 12:3. More preferably the ratio of the outer diameter of the dirt container to the outer diameter of each cyclone is no less than 16:3. Most preferably, the ratio of the outer diameter of the dirt container to the outer diameter of each cyclone is about 20:3.
Preferably, the vacuum cleaner comprises a body with a handle and a dirty air duct located in the path of air flow up stream of the cyclonic separation apparatus. Alternatively, the vacuum cleaner comprises a flexible hose located in the path of the air flow upstream of the cyclonic separation apparatus. Alternatively, the vacuum cleaner comprises an elongate body with a handle at one end and a cleaner head at an opposite end, wherein the cleaner head is located in the path of the air flow upstream of the cyclonic separation apparatus. Preferably, the vacuum cleaner comprises at least one support wheel for supporting the vacuum cleaner upon a floor, wherein the at least one support wheel rotates about the central axis of the cyclonic separation apparatus. The cyclonic separation apparatus is located close to the floor so that fluid communication with the cleaner head is as shortened. This reduces energy loss by reducing the overall length of the air flow path. Preferably, the at least one support wheel defines a cylinder surrounding the dirt container. The cyclonic separation apparatus performs an additional role of axle to the support wheel which makes the vacuum cleaner more compact and reduces the number of parts. Preferably, the elongate body is telescopically extendible so that it can be extended for use and retraced for storage in a much smaller location. Alternatively, the vacuum cleaner is a blower-vac, which is an outdoor garden tool which can perform the role of blowing garden debris for collection and the role of vacuum cleaner for sucking garden debris into a container.
Further features and advantages of the present invention will be better understood by reference to the following description, which is given by way of example and in association with the accompanying drawings, in which:
Referring to
Referring to
The motor 16 and the fan 18 are housed in a motor fan housing 27 comprising a generally cylindrical body portion 28 enclosing the motor and a generally circular head portion 29 enclosing the fan. The head portion 29 has a larger diameter than the body portion 28. The motor fan housing 27 comprises a perforated end cap 30 mounted upon the head portion on the opposite side to the body portion. The end cap 30 protects the fan. The end cap has a circular array of perforations 36 near where air flow is expelled from the fan. The head portion acts as a baffle to direct air flow from the fan and out the perforations. The body portion has an array of bottom slots 32 around the bottom of the motor and an array of top slots 34 about where the drive shaft 20 protrudes from the top of the motor.
The cyclonic separation apparatus 8 comprises a pre-fan filter 40, a vortex finder assembly 50, a generally cylindrical inner wall 60, a cyclone seal 70, a cyclone assembly 80, a cylindrical perforated intermediate wall 90, a circular bulkhead 100, a tapered funnel 110, a transparent generally cylindrical dirt container 120, and a circular bowl door 130 all arranged about the central axis 21 of the motor drive shaft 20.
The pre-fan filter 40 is an annular shape surrounding the top air flow slots 34 of the body portion 28 of the motor fan housing 27. The pre-fan filter is enclosed in an annular shell 42 except where the pre-fan filter communicates with the vortex finder assembly 50 and with the top air flow slots 34 of the body portion 28. This permits air flow from the cyclonic separating apparatus, through the pre-fan filter and on to the fan.
The vortex finder assembly 50 comprises planar ring 52 moulded with twelve hollow cylindrical vortex finders 54 protruding from one side of the planar ring. Holes 56 through the vortex finders penetrate the opposite side of the planar ring whereupon the pre-fan filter 40 is seated. The pre-fan filter 40 helps to muffle high frequency sounds caused by Helmholtz resonance as air flows through the vortex finder holes 56. The vortex finders are arranged in a circular array about the central axis 21 of the motor drive shaft 20. Each vortex finder has its own longitudinal central axis 57 arranged parallel to the central axis 21. The vortex finders may have longitudinal internal ribs (not shown) along the vortex finder holes to further reduce high frequency noise caused by Helmholtz resonance. The longitudinal ribs also tend to straighten air flow in the vortex finder to help reduce energy losses as the air flows into the pre-fan filter 40.
The inner wall 60 is a generally cylindrical shape in two portions of different diameter. The inner wall comprises an annular flange 62 at an open end of the inner wall, a hollow cylindrical cup 64 at an opposite closed end of the inner wall, a hollow cylindrical wall 66 and an annular shoulder 68. The flange extends radially outwardly from the open end of the cylindrical wall. The cylindrical wall is located between the flange and the cylindrical cup. The cylindrical wall has a larger diameter than the cylindrical cup. The annular shoulder joins the cylindrical wall to the cylindrical cup. The shoulder is perforated with a circular array of twelve holes 69 spaced at equi-angular intervals about the central axis 21. The annular flange 62 is connected to an annular roof wall 121 of the dirt container 120.
The vortex finder assembly 50 is seated in the cylindrical wall 66 with the planar ring 52 facing the shoulder 68 and the vortex finders 54 protruding through the shoulder's holes 68. The pre-fan filer 40 is nested within the cylindrical wall 66. The bottom of the motor fan housing's body portion 28 is nested within the cylindrical cup 64.
The cyclone seal 70 is perforated with a circular array of twelve holes 72 spaced at equi-angular intervals about the central axis 21. The shoulder 68 of the inner wall 60 is seated upon the cyclone seal. The vortex finders 54 protrude through the seal holes 72.
The cyclone assembly 80 comprises a cylindrical collar 82 and a circular array of twelve cyclones 84 surrounded by the collar. The cyclones are spaced at equi-angular intervals about the central axis 21. Each cyclone has a hollow cylindrical top part 85 and a hollow frustro-conical bottom part 86 depending from the cylindrical top part and terminating with a discharge nozzle 87 at the bottom of the cyclone.
The shoulder 68 of the inner wall 60 is arranged upon the cyclone assembly 80 with the cyclone seal 70 interposed therebetween. The collar 82 has the same outer diameter as, and abuts with, the cylindrical wall 66 of the inner wall 60. The vortex finders 54 protrude through the holes 72 in the cyclone seal and into the cylindrical top part 85 of a respective cyclone 84. The only passage through the top of the cyclone 84 is via its vortex finder 54 which acts as an air flow outlet port to the pre-fan filter 40. Each vortex finder is concentric with its respective cyclone. The plane of each nozzle 87 is inclined with respect to the central axis 57. This helps to prevent dust and dirt particles from re-entry after discharge from the nozzle.
The cylindrical top part 85 of each cyclone 84 has an air inlet port 88 arranged tangentially through the side of the cyclone and proximal the vortex finder 54. The twelve air inlet ports are in communication with a distribution chamber 170 below the collar 82 around the cyclones 84, as is described in more detail below.
The intermediate wall 90 is arranged upon the cyclone assembly 80. The intermediate wall 90 has the same outer diameter as, and abuts with, the cylindrical collar 82.
The bulkhead 100 is arranged upon, and has approximately the same outer diameter as, the intermediate wall 90. The bulkhead 100 is perforated by a circular array of twelve holes 102 spaced at equi-angular intervals about the central axis 21. The discharge nozzles 87 of the cyclones 84 protrude through respective bulkhead holes 102. The bulkhead 100 has a circumferential lip 104 inclined radially outwardly from the central axis 21 towards the bowl door 130. The lip 104 protrudes a small way from the intermediate wall 90.
The tapered funnel 110 comprises a hollow circumferential skirt 112, a frustro-conical cone 114 depending from the skirt, and a hollow cylindrical nose 116 depending from the cone. The skirt is arranged upon, and has approximately the same outer diameter as, the bulkhead. The cone tapers radially inwardly from the bulkhead 100 towards the bowl door 130. A perforated portion 118 of the skirt protrudes axially rearward from the cone towards the bowl door 130.
The generally cylindrical dirt container 120 comprises the annular roof wall 121 and a hollow cylindrical exterior wall 122 with a frustro-conical dirt collection bowl 124 depending from the exterior wall. The dirt container has a dirty air inlet port 126 arranged tangentially through the exterior wall 122. The dirt container 120 has a circumferential lip 128 inclined radially inwardly towards the central axis 21 and towards the bowl door 130. The lip 128 protrudes a small way in from the transition between the exterior wall and the dirt collection bowl. The motor fan housing's head portion 29 is nested within the centre of the annular roof wall 121. The annular roof wall is detachably connected to an outer circumferential edge 138 of the exterior wall 122. The annular roof wall 121 may be connected to the exterior wall 122 and the inner wall 60 by snap-fit, bayonet fit, interlocking detents, interference fit or by a hinge. A resilient seal or seals made of polyethylene, rubber or a similar elastomeric material is provided around the annular roof wall to ensure airtight connection with the exterior wall.
The bowl door 130 is detachably connected to an outer circumferential edge 132 of the dirt collection bowl 124. The bowl door abuts the cylindrical nose 116 thereby dividing the dirt collection bowl into two separate chambers: a generally circular chamber 134 inside the tapered funnel 110 and a generally annular chamber 162 outside the tapered funnel. The bowl door 130 may be connected to the dirt collection bowl 124 by snap-fit, bayonet fit, interlocking detents, interference fit or by a hinge. A resilient seal made of polyethylene, rubber or a similar elastomeric material is provided around bowl door 130 to ensure airtight connection with the dirt collection bowl.
The annular flange 62 of the inner wall 60 is in complementary mating relationship with a circular ring 123 protruding from inside the annular roof wall 121. The nose 116 is in complementary mating relationship with a circular ring 140 protruding from inside the bowl door 130. This ensures that components of the cyclonic separation apparatus 8 remain concentric with the central axis 21 when the bowl door is closed.
Between the annular roof wall 121 and the bowl door 130, the various components of the cyclonic separation apparatus 8 (i.e. pre-fan filter 40, vortex finder assembly 50, inner wall 60, cyclone seal 70, cyclone assembly 80, intermediate wall 90, bulkhead 100, tapered funnel 110) are arranged upon each other by detachable connection, typically a snap-fit, bayonet fit, interlocking detents, or interference fit. The permits disassembly and reassembly, without tools, of the cyclonic separation apparatus 8 in order to clean, or replace, its individual components. Resilient seals made of polyethylene, rubber or a similar elastomeric material, or other suitable seal material, are provided around connections of the annular flange 62 and pre-fan filter shell 42 with the annular roof wall 121. The seals are to ensure airtight connection. The internal diameter of the dirt container 120 and the bowl door 130 is large enough to permit removal of the components of the cyclonic separation apparatus 8 (i.e. pre-fan filter 40, vortex finder assembly 50, inner wall 60, cyclone seal 70, cyclone assembly 80, intermediate wall 90, bulkhead 100, tapered funnel 110) through either end of the dirt container.
In use, dirty air flows, under the influence of the fan 18, in the dirty air inlet 12, up the dirty air duct 10 and into the cyclonic separation apparatus 8 where dust and dirt entrained in the air flow is separated therefrom. The dust and dirt is collected within the cyclonic separation apparatus. The air flows out the cyclonic separation apparatus 8, through the pre-fan filter 40, into the motor fan housing 27 via the top slots 34, though the fan 18 and out the perforations 36 in the end cap 30.
Referring to
The first cyclonic separating unit 160 comprises the cylindrical dirt container 120. The second cyclonic separating unit 150 comprises the circular array of twelve cyclones 84. The dirt container is concentric with the central axis 21 of the motor drive shaft 20. The distribution chamber 170 is bounded by the hollow cylindrical cup 64 of the inner wall, cyclone assembly 80, intermediate wall 90 and bulkhead 100. The second cyclone unit 150 received air flow from the first cyclone unit 160 via the distribution chamber 170.
The exterior wall 122 of the dirt container 120 has a diameter of approximately 130 mm. The cyclones 84 have a much smaller diameter than the dirt container. Helical air flow in the cyclones experiences greater centrifugal forces than in the annular chamber. Thus, the cyclones of the second cyclonic separating unit 150, when combined, have higher separation efficiency than the dirt container of the first cyclonic separating unit 160.
The air flow pathway though the cyclonic separation apparatus 8 is described in more detail with reference to
Referring to
Referring to
As can be seen in
Referring to
The pre-fan filter is in communication with the motor fan housing 27. Cleaned air flows, via the top slots 34 in the motor fan housing, to the axial input 22 of the fan 18, out the tangential output 24 of the fan and through the perforations 36 of the end cap 30 where it is exhausted from the vacuum cleaner 2. Dust and dirt separated by the first and second cyclonic separating units and deposited in the dirt collection bowl 124 which can be emptied by opening the bowl door 130.
Returning to
Returning to
Referring to
Referring to
Referring to
Returning to
The motor cooling inlet ports 31 are spaced at equiangular intervals about the central axis 21. The motor cooling inlet ports are axially aligned with the gaps 59 between the vortex spaces seals 58 and with the bottom air flow slots 32 in the motor fan housing 27. This axial alignment is to help minimise any resistance encountered by the motor cooling air flow along the motor cooling passages 61a, 61b. The bottom motor vents 17a are also aligned with the bottom air flow slots 32 in the motor fan housing 27 to help minimise any resistance encountered by the motor cooling air flow.
The clean motor cooling air flow pathway is separate from the air flow pathway through the cyclonic separation apparatus 8 up to the axial input of the fan 18. This has particular benefits in vacuum cleaning. Typically, motor speed increases as the fan encounters resistance to volumetric air flow and the pressure across the fan increases accordingly. An example of how this may occur is when the vacuum cleaner is operational and the dirty air inlet contacts carpet, hard floor, curtains or other surface to restrict air flow. Should the air flow path through the cyclonic separation apparatus 8 become blocked, or impeded, for whatever reason, the motor cooling air flow path would not necessarily be blocked, or impeded. Instead, the increased pressure across the fan 18 would increase suction through the motor cooling air flow pathway. This has the benefit of increased motor cooling when the motor is working hardest and cooling is needed most.
Referring to
Referring to
Referring to
The motor has a drive shaft 220 with a longitudinal central axis 221. The fan is a centrifugal fan 218 with an axial input 222 facing away from the motor and a tangential output 224. The fan has a diameter of 68 mm. The fan is mounted upon the drive shaft at the top of the motor. The cells 217 are arranged in a circular array about the motor 216 with the longitudinal axis of the cells parallel to the central axis 221, as is shown most clearly in
The main body 204 comprises a central housing 226, a motor housing 228, a frame 230 and an end cap 232. The fan 218 is housed in the central housing 226. The central housing is connected to the handle 206. The motor 216 and the cells 217 are housed in the motor housing 228. The motor housing is generally elongate to suit the profile of the cells. The end cap 230 is connected to an opposite end of the motor housing to the fan. The end cap has a circular array of perforations 236.
The frame 230 connects the central housing 226 to the cyclonic separation apparatus 208. One end of the frame supports a pre-fan filter 240 arranged in front of the axial input 222 of the fan 218. The other end of the frame supports the cyclonic separation apparatus.
The outlet duct 260 is defined by a generally oval-shaped duct wall 262 arranged upon the frame 230 to form the outlet duct between the duct wall and frame. The outlet duct 260 provides an air flow path between the cyclonic separation apparatus 208 and the pre-fan filter 240. The duct wall is detachable from the frame. The duct wall is transparent to permit visual inspection of the pre-fan filter. The duct wall is removed from the frame if the pre-fan filter needs cleaning or replacement.
The cyclonic separation apparatus 208 comprises, a vortex finder assembly 250, a vortex finder seal 270, a cyclone assembly 280, a cylindrical perforated intermediate wall 290, a circular bulkhead 300, a tapered funnel 310, a transparent generally cylindrical dirt container 320 with a longitudinal central axis 321, and a circular dirt collection bowl 330 all arranged about the central axis 321 of the dirt container 320.
The vortex finder assembly 250 comprises a planar generally circular base 252 with six hollow cylindrical vortex finders 254. Each vortex finder has a central through-hole 256 and its own longitudinal central axis 257. The vortex finders are arranged in a circular array about the central axis 321 of the dirt container 320. Each vortex finder is parallel to the central axis 321. The vortex finders protrude from one side of the base. A small portion of each vortex finder also protrudes from the opposite side of the base. The vortex finders may have longitudinal internal ribs (not shown) along the through-holes to help dampen high frequency sounds caused by Helmholtz resonance as air flows through the vortex finder though-holes 256.
The cyclone assembly 280 comprises a generally cylindrical collar 282 and a circular array of six cyclones 284 surrounded by the collar. The cyclones are spaced at equi-angular intervals about the central axis 321 of the dirt container 320. Each cyclone has a hollow cylindrical top part 285 and a hollow frustro-conical bottom part 286 depending from the cylindrical top part and terminating with a discharge nozzle 287 at the bottom of the cyclone.
The vortex finder assembly 250 is arranged upon the collar 282 of the cyclone assembly 280. The vortex finders 254 protrude into the cylindrical top part 285 of a respective cyclone 284. The only passage through of the top of the cyclone 284 is via its vortex finder 254 which acts as an air flow port to the outlet duct 260. Each vortex finder is concentric with its respective cyclone. The plane of each nozzle 287 is inclined with respect to the central axis 257. This helps to prevent dust and dirt particles from re-entry after discharge from the nozzle.
The cylindrical top part 285 of each cyclone 284 has an air inlet port 288 arranged tangentially through a side of the cyclone and proximal the vortex finder 254. The six air inlet ports are in communication with a distribution chamber 370 located below the collar 282 around the cyclones 284 as described in more detail below.
The intermediate wall 290 is arranged upon the cyclone assembly 280. The intermediate wall 290 has approximately the same outer diameter as, and abuts with, the cylindrical collar 282.
The bulkhead 300 is arranged upon, and has approximately the same outer diameter as, the intermediate wall 290. The bulkhead 300 is perforated by a circular array of six holes 302 spaced at equi-angular intervals about the central axis 321. The discharge nozzles 287 of the cyclones 284 protrude through respective bulkhead holes 302. The bulkhead 300 has a circumferential lip 304 inclined radially outwardly from the central axis 321 towards the collection bowl 330. The lip 304 protrudes a small way from the intermediate wall 290.
The tapered funnel 310 comprises a hollow circumferential skirt 312, a frustro-conical cone 314 depending from the skirt, and a hollow cylindrical nose 316 depending from the cone. The skirt is arranged upon, and has approximately the same outer diameter as, the bulkhead 300. The cone tapers radially inwardly from the bulkhead towards the collection bowl 330. A perforated portion 318 of the skirt protrudes axially rearward from the cone towards the collection bowl 330.
The generally cylindrical dirt container 320 comprises a hollow cylindrical exterior wall 322 with a circular shoulder 324 extending radially inwardly from the top of the exterior wall. The dirty container has a dirty air inlet port 326 arranged tangentially through the exterior wall 322. The dirty air inlet port communicates with the dirty air duct 210. The exterior wall 322 is rotatingly connected to the frame 230 to enable the cyclonic separation apparatus 208 to rotate about its central axis 321 in relation to the main body 204. The dirty air duct 210 is rotatable with the cyclonic separation apparatus 208, as is shown in
The planar base 252 of the vortex finder assembly 250 nests within the aperture in the circular shoulder 324 of the dirt container 320. The collar 282 of the cyclone assembly 280 abuts the circular shoulder 324. The cyclones 284 are located within the dirt container 320.
The dirt collection bowl 330 is detachably connected to an outer circumferential edge 332 of the dirt container 320. The dirt collection bowl abuts the nose 316 thereby dividing the dirt container and dirt collection bowl into two separate chambers: a circular chamber 334 inside the tapered funnel 310 and a generally annular chamber 362 outside the tapered funnel. The dirt collection bowl 330 may be connected to the dirt container's outer circumferential edge by snap-fit, bayonet fit, interlocking detents, interference fit or by a hinge. A resilient seal 336 made of polyethylene, rubber or a similar elastomeric material is provided around the dirt collection bowl 330 to ensure airtight connection with the dirt container.
The dirt container 320 has an annular lip 328 inclined radially inwardly to the central axis 321 towards the collection bowl 330. The lip 328 protrudes a small way in from the exterior wall. The lip 328 is proximal to the bowl 330.
The nose 316 of the tapered funnel 310 is in complementary mating relationship with a circular ring 340 protruding from inside the dirt collection bowl 330. This ensures that components of the cyclonic separation apparatus 208 remain concentric with the central axis 321 of the dirt container 320.
In use, dirty air flows, under the influence of the fan 218, in the dirty air inlet 212, up the dirty air duct 210 and into the cyclonic separation apparatus 208 where dust and dirt entrained in the air flow is separated therefrom. The dust and dirt is collected within the cyclonic separation apparatus. The air flows out the cyclonic separation apparatus 208, via the through-holes 256 of the vortex finders, along the outlet duct 260, through the pre-fan filter 240, through the fan 218 and over the motor 216 and batteries cells 217 via the motor housing 228 and out the perforations 236 in the end cap 230.
Referring to
The first cyclonic separating unit 360 comprises the cylindrical dirt container 310. The second cyclonic separating unit 350 comprises the circular array of six cyclones 284. The dirt container is concentric with the central axis 321 of the dirt container. The distribution chamber 370 is bounded by the collar 282, cyclone assembly 280, intermediate wall 290 and bulkhead 300. The second cyclonic separating unit 350 receives air flow from the first cyclonic separating unit 360 via the distribution chamber 370.
The exterior wall 322 of the dirt container 320 has a diameter of approximately 120 mm. The cyclones 284 have a smaller diameter than the annular chamber 362. Helical air flow in the cyclones experiences greater centrifugal forces than in the dirt container. Thus, the cyclones of the second cyclonic separating unit 350, when combined, have higher separation efficiency than the dirt container of the first cyclonic separating unit 360.
The air flow pathway though the cyclonic separation apparatus 208 is described in more detail with reference to
Referring to
Referring to
As can be seen in
Referring to
Returning to
Dust and dirt separated by the first and second cyclonic separating units and deposited in the dirt collection bowl 330 which can be opened for emptying.
Referring to
The vortex finder seal 270 seals the connections between the vortex finder assembly 250 and the dirt container 320 in an airtight manner. An outlet duct seal 266 seals the connection between the frame 230 and the outlet duct wall 262 in an airtight manner. The vortex finder seal 270 and the outlet duct seal 266 are made of polyethylene, rubber or a similar elastomeric material.
Certain components of the cyclonic separation apparatus 208 are detachably connected, typically by a snap-fit, bayonet fit, interference fit or by interlocking detents. This permits disassembly and reassembly, without tools, of the cyclonic separation apparatus in order to clean, or replace, its individual components, as is described with reference to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
The motor has a drive shaft 420. The fan 418 is mounted upon the drive shaft at the top of the motor. The fan has a diameter of approximately 68 mm. The cells 417 are arranged about the motor 416. In use, the motor drives the fan to generate air flow through the cyclonic separation apparatus, as will be described in more detail below.
The main body 404 comprises a central housing 426 and a frame 430. The motor 416, fan 418 and cells 417 are housed in the central housing 426. The central housing is connected to the handle 406. The central housing has an array of perforations 436 near the bottom of the motor. The perforations 436 are for air flow expelled from the central housing.
The frame 430 connects the central housing 426 to the cyclonic separation apparatus 408. One end of the frame supports a pre-fan filter 440 arranged in front of the fan's input. The other end of the frame supports the cyclonic separation apparatus. The cyclonic separation apparatus is rotatingly connected to the frame.
Outlet duct 460 comprises a duct wall 462 arranged upon the frame to form a passage between the duct wall and frame approximately 10 mm deep. The outlet duct 460 provides an air flow path between the cyclonic separation apparatus 408 and the pre-fan filter 440. The duct wall is detachable from the frame. The duct wall is transparent to permit visual inspection of the pre-fan filter. A resilient seal made of polyethylene, rubber or similar elastomeric material is provided around the duct wall to ensure air tight connection with the frame. The duct wall is removed from the frame if the pre-fan filter needs cleaning or replacement.
The cyclonic separation apparatus 408 comprises a vortex finder assembly 450, a cyclone assembly 480, and an elongate generally oval-shaped dirt container 520 with a transparent door 530.
The vortex finder assembly 450 has a hollow cylindrical vortex finder 452 with a tapered deflector fin 454. The vortex finder has a central through-hole 456 with a longitudinal central axis 457. The deflector fin protrudes radially from the outer surface of the vortex finder. In the present embodiment the tapered deflector fin is triangular although it could have another tapered profile. The triangular profile of the deflector fin 454 is a right angled triangle.
The cyclone assembly 480 comprises a cyclone 484 and a dirty air inlet port 488. The cyclone has a hollow cylindrical body 485 with the dirty air inlet port and a hollow frustro-conical bottom body 486 extending from the cylindrical body and terminating with a discharge nozzle 487 at the narrower end. The air inlet port is arranged tangentially through a side of the cylindrical body. The vortex finder 454 is arranged inside the cyclone 484. The vortex finder is concentric with the cyclone. The deflector fin 454 is arranged transverse to the path of air flow from the air inlet port. The radially extending short side of the deflector fin abuts the frame 430. An apex 4541 of the deflector fin is proximal to the air inlet port. The hypotenuse side of the deflector fin tapers radially inwardly from the apex to the end of the vortex finder proximal to the discharge nozzle 487. There is a small gap of Z approximately 5 mm between the apex and the cylindrical body 485 of the cyclone 484.
The dirt container 520 is connected to the central housing 426 at one end and the discharge nozzle 487 of the cyclone 484 at the other end. The dirt container comprises a perimeter wall 522 following the outer perimeter of the elongate generally oval-shaped dirt container and base wall 524 with a cylindrical pocket 526 protruding from the base wall into the confines of the dirt container. The cyclone 484 is in communication with the dirt container where the nozzle 487 protrudes through the base wall 524. The bottom of the motor 416 is seated inside the pocket 526 on the opposite side to the dirt container thereby reducing the overall width of the vacuum cleaner by about 20 to 25 mm.
The cyclone 484 has a curved fin 490 protruding axially from the discharge nozzle 487 into the dirt container 520. The curved fin circumscribes an arc of about half the circumference of the nozzle facing the pocket 526. The ends of the curved fin taper towards the nozzle. The dirt container has a flat fin 492 protruding from the base wall 524. The flat fin extends tangentially from the top of the pocket 526 to about the middle of the dirt container. The flat fin is generally parallel to an adjacent initial flat portion 522a of the perimeter wall 522 uppermost on the dirt container in normal use.
The door 530 is detachably connected to the perimeter wall 522 of the container 520. The door 530 may be connected to the dirt container by snap-fit, interlocking detents, a hinge 528 or by interference fit with the dirt container's exterior wall. In the example shown, the door is held firmly closed by a spring-loaded latch 529. A resilient seal (not shown) made of polyethylene, rubber or a similar elastomeric material is provided around the door 530 to ensure connection to the dirt container 320 in an airtight manner. Dust and dirt separated by the cyclonic separation apparatus and deposited in the dirt container 520 can be emptied by opening the door 530. The door is transparent to enable visual inspection of when the dirt container 520 is full and is in need of emptying.
In use, dirty air flows, under the influence of the fan 418, in the dirty air inlet 412, up the dirty air inlet duct 410 and into the cyclonic separation apparatus 408 where dust and dirt entrained in the air flow is separated therefrom. The dust and dirt is collected within the cyclonic separation apparatus. Air flows out the cyclonic separation apparatus 408, via the through-hole 456 of the vortex finder, along the outlet duct 460, through the pre-fan filter 440, through the fan 418 and over the motor 416 and cells 417 via the central housing 426 and out the perforations 436 in the central housing.
Referring to
The partially-cleaned air flow (double-headed arrows) is directed by the curved fin 490 and a proximal curved portion 522d of the perimeter wall 522 to leave the cyclone 484 in an anti-clockwise upward direction, as viewed in
Having deviated past the curved fin 490, clean air flow (single-headed arrows) turns back on itself and, under the influence of the fan, flows in a narrow inner helical path into the vortex finder's through-hole 456 from where it leaves the cyclonic separation apparatus 408 and enters the outlet duct 460.
Referring to
Referring to
Referring in particular to
The dirty air duct 610 and the battery pack 900 are rotatable, with the cyclonic separation apparatus 8, about the central axis 21 through an arc subtending 210 degrees from a folded position. This allows the vacuum cleaner 602 to be pointed in different directions, whilst a user is able to hold the vacuum cleaner in the same orientation. The vacuum cleaner may be used to access awkward spaces and can be held more comfortably by orientating the main axis 605 of the main body 604 to suit the user and adjusting the position of the dirty air inlet 612 to point at a surface to be cleaned, rather than orientating the main axis to best suit the surface to be cleaned and requiring the user to hold the vacuum cleaner in whichever orientation this demands.
Referring to
The battery pack 910 has a curvilinear inner wall 902 which is shaped to cradle the cylindrical dust container 120. The battery pack is detachably connected to the dust container 120. The cells may be recharged in situ. The battery pack may be detached from the dirt container to enable replacement, or external recharging of the cells, if necessary. The battery pack has a pair of feet 912 arranged to support the vacuum cleaner 702 in a stable manner when placed upon a flat surface. The cells have a generally cylindrical shape. Longitudinal axes of the cells are arranged parallel to the central axis 21 of the motor 16.
Referring to
The vacuum cleaner comprises a battery pack 900 of rechargeable cells 917 to energise the motor 16 when electrically coupled by an on/off switch. Referring to
Returning to
Returning to
Referring to
Referring to
Referring to
The curved plate cells 927 improve use of the internal cavity of the battery packs 920 by eliminating the gaps which naturally exist between the cylindrical cells 917. This results in a more compact design of battery pack with reduced packaging and a higher energy density.
The curvilinear or cylindrical inner walls 902, 922 of the curvilinear battery pack 900, 910 and the annular battery pack 920 embrace, or attach themselves to, the dirt container 120. This facilitates new design choices for accommodating cells in a compact manner.
The skilled addressee will appreciate that the rechargeable cells can be any type of energy accumulator, including rechargeable Lithium Ion, Nickel Metal Hydride or Nickel Cadmium rechargeable cells, for driving the electric motor 16, 216, 416.
The skilled addressee will appreciate that the specific overall shapes and sizes of the arrangements comprising the motor 16, 216, 416 the fan 18, 218, 418 and the cyclonic separation apparatus 8, 208, 408 can be varied according to the type of vacuum cleaner in which either of the arrangements is to be used. For example, the overall length or width of each arrangement, and, in particular, the cyclonic separation apparatus, can be increased or decreased with respect to its diameter, and vice versa.
In particular, the hand-holdable vacuum cleaner 702 of
Further, the hand-holdable vacuum cleaner 802 of
The motor 16, 216, 416 discussed above is a typically a brushed d.c. motor with its drive shaft 20, 220, 420 directly coupled to the centrifugal fan 18, 218, 418. The motor's drive shaft has a rotational speed within a range of 25,000 and 40,000 revolutions per minute (rpm). A centrifugal fan with a rotational speed within this range has an outer diameter approximately double the outer diameter of the motor can in order to have sufficient tip speed to generate the required volumetric flow rate through the cyclonic separation apparatus. The skilled person will appreciate that the motor 16, 216, 416 can be a d.c. motor, an a.c. motor, or an asynchronous multi-phase motor controlled by an electronic circuit. A permanent magnet brushless motor, a switched reluctance motor, a flux switching motor, or other brushless motor type, may have a high rotational speed within a range of 80,000 to 120,000 rpm. If such a high speed motor were used then the fan diameter could be at least halved and yet still generate the required volumetric flow through the cyclonic separation apparatus because the fan's tip speed would be so much higher. This would make the fan's outer diameter the same as the motor can's outer diameter and could possibly make it less than the motor can's outer diameter if the motor operates at around the upper end of the high rotational speed range. A smaller diameter fan operating within this range of high rotational speeds would typically be an impeller although it may be an axial fan or a centrifugal fan. The outer profile of the smaller fan coupled to the drive shaft of the high rotational speed motor would have a generally cylindrical outer profile. This provides additional flexibility in the layout of the cyclonic separation apparatus.
In a modification of the first or second embodiment of a cyclonic separation apparatus 8, 208 which is not shown in the drawings, the cyclones 84, 284 can be rearranged to accommodate a high rotational speed permanent magnet brushless motor, a switched reluctance motor or a flux switching motor coupled to a fan which is coaxial with the motor and has an outer diameter substantially the same as or less than the outer diameter of the motor. The generally cylindrical outer profile of high speed motor and fan can be sunk into the cyclonic separation apparatus amongst the cyclones and clustered into a generally circular array. Air flow can be directed to the axial input of the fan and expelled from the tangential output of the fan by a baffle. The high speed motor and fan may be located on the periphery of the circular array in which case air flow from the fan may be expelled from one side of the circular array and directed out of the cyclonic separating apparatus. The high speed motor and fan may be nested near, or at, the middle of the circular array in which case air flow from the fan may be expelled from one end of the circular array and directed out of the cyclonic separating apparatus. If the high speed motor and fan were nested in a circular array of cyclones inclined with respect to a central axis, like, for example, a modified version of the cyclones disclosed by GB 2 440 110 A, then air flow from the fan may be expelled from one end of the circular array of cyclones or through gaps between the cyclones.
| Number | Date | Country | Kind |
|---|---|---|---|
| 11184819 | Oct 2011 | EP | regional |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20060042206 | Arnold et al. | Mar 2006 | A1 |
| 20070266678 | Makarov et al. | Nov 2007 | A1 |
| 20080222840 | Worker et al. | Sep 2008 | A1 |
| 20080271284 | Wood et al. | Nov 2008 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20130091813 A1 | Apr 2013 | US |
