A VACUUM CLEANER

Abstract: A vacuum cleaner head (10) comprising a curved body (15) about which fluid can circulate, the curved body having a lower portion (17) which in use is adapted to be adjacent the area to be vacuumed, the lower portion being dimensioned to provide a lower pressure surface, the curved body also having an upper portion (18) dimensioned to provide a higher pressure surface, fluid acceleration means (21) to accelerate the fluid about the curved body, a fluid stream splitter (31) in the upper portion of the curved body to split the fluid into a recirculated portion which continues to move about the curved body, and a waste portion which passes into a dust collecting chamber (32) and is exhausted therefrom.

Description: TITLE A VACUUM CLEANER TECHNICAL FIELD This invention relates to a vacuum cleaner and particular to a floor vacuum cleaner for use on carpets and the like. BACKGROUND ART Vacuum cleaners develop suction by means of a fan which discharges a powerful stream of air from the rear end of the casing. This sets up a powerful inflowing current of air which carries along any dust particles from the carpet or floor to which a suction nozzle is applied. The fan has a large number of blades set at an angle, the rotation setting up a flow of air in the axial direction. The air stream is passed through a bag in which the dust is precipitated and collected without appreciably obstructing the air flow. One disadvantage with vacuum cleaners is that the entire volume of air passes into the dust collecting chamber and must pass through the walls of the dust bag. Should the dust bag become too full or clogged, this will reduce the efficiency of the vacuum cleaner and can result in damage to the vacuum cleaner itself. The efficiency of the vacuum cleaner is dependent upon two factors being the air flow rate and the suction power. The suction performance is the product of two factors. Thus, when the flow rate is maximum, the suction is low and conversely when suction is high, the flow rate is low. For a vacuum cleaner to function efficiently, it is necessary for both the suction and the flow rate to be adequate. Another disadvantage with conventional vacuum cleaners is that the air flow speed and volume is relatively low. The air flow speed along the carpet or ground and into the vacuum cleaner head largely determines the efficiency of the vacuum cleaner. Thus a high speed of air and a high volume of air would be desirable. Other disadvantages of vacuum cleaners are the relatively high power consumption of the motor being typically over l,000Kw making efficient vacuum cleaners difficult to be battery powered; and the low efficiency of the fan. DISCLOSURE OF THE INVENTION The present invention is directed to a vacuum cleaner which can overcome the abovementioned disadvantages or provide the public with a useful or commercial choice. In one form, the invention resides in a vacuum cleaner head comprising a curved body about which fluid can circulate, the curved body having a lower portion which in use is adapted to be adjacent the area to be vacuumed, the lower portion being dimensioned to provide a lower pressure surface, the curved body also having an upper portion dimensioned to provide a higher pressure surface, fluid acceleration means to accelerate the fluid about the curved body, a fluid stream splitter in the upper portion of the curved body to split the fluid into a recirculated portion which continues to move about the curved body, and a waste portion which passes into a dust collecting chamber and is exhausted therefrom. The curved body may be in the form of a doughnut or toroid. The curved body need not be symmetrical and may be slightly elliptical in cross- section. The curved body need not be entirely curved, and portions of the curved body may be straight if desired. By providing a doughnut or toroid shape, fluid travelling through the central passageway in the shape and under the lower portion of the body will expand as it passes over a surface of increasing surface area, which can also be seen as a lower pressure surface. As the fluid passes over this area and back into the central passage, the fluid passes through an upper region which has a decreasing surface area and thus can be seen as a higher pressure surface. If the curved body is doughnut or toroidal shaped, the fluid acceleration means may be positioned within the central passageway. Preferably, the fluid acceleration means is positioned in a lower portion of the central passageway, that is the portion closer towards the carpet or ground surface to be cleaned. The fluid acceleration means may itself comprise a fan which can be of the bladed type. The fan may be driven by a motor such as an electric motor and this may be positioned above the fan and within the central passageway. The motor may be housed within a sealed compartment within the central passageway there being sufficient room to allow fluid to circulate about the curved body and between the curved body and the housing in which the motor is positioned. The lower end of the curved body may have a blowing slot. If the curved body is a doughnut or toroidal shape, the lower end of the passageway may be sealed off with just a small, typically annular slot being present to allow fluid to blow through the slot and over the low pressure surface. The upper portion of the curved body has a fluid stream splitter which may comprise a disc or a curved member. The splitter can divide the fluid into a portion which recirculates about the curved body, and a split off waste portion which passes into a dust collecting chamber. It is preferred that the fluid acceleration means is positioned in the central passageway below the fluid splitter and above the fluid blowing slot. BRIEF DESCRIPTION OF THE DRAWING Figure 1 illustrates in section a vacuum cleaning head according to an embodiment of the invention. BEST MODE Referring to Figure 1, there is shown a vacuum cleaner head 10 to which a handle 11 can be attached in the usual manner, the handle not forming any part of the invention. Vacuum cleaner head has an outer housing 12 which can be made from plastic or metal. Outer housing 12 is hollow and dome shaped and has a lower thickened peripheral edge 13 to provide strength to the housing and an upper thinner wall configuration 14. Within housing 12 is a curved body 15 in the form of a doughnut or toroid. Body 15 can be mounted inside the housing using connecting struts (not shown) or other types of mountings. Body 15 by being doughnut or toroidal in shape has a central passageway 16. Body 15 also has a lower portion 17, an upper portion 18, an inner portion 19 and an outer portion 20. Inside central passageway 16 is an air acceleration means in the form of a bladed fan 21. Fan 21 has a number of blades 22 attached to a hub 23 the hub being attached to a shaft 24 which is driven by a motor 25. Motor 25 is housed within a housing 26 to protect it from dust and debris and also to silence the motor. The fan is preferably of a design which is described in my earlier international patent application PCT/AU93/00581. Below fan 21 is a plate 27 (which could be an extension of hub 23 or a separately formed plate) . Plate 27 extends across the lower portion of central passageway 16 but is spaced inwardly from the inner ends of body 15 to define an annular blowing slot 28. The blowing slot ensures that fluid is blown over the lower pressure surface area 17 and by virtue of the fluid being blown through slot 28, it will adhere to curved body 15 and will follow the surface of the body by virtue of the coanda effect. As the fluid passes over the lower pressure surface, it expands by virtue of the increasing surface area of the curved body and in doing so it will entrain adjacent fluid. This provides the cleaning effect and by positioning lower portion 17 above the carpet or ground surface, any dirt or dust will be entrained or picked up by the circulating air stream. Fresh air 40 will also be entrained and will pass under peripheral edge 13 and into the circulating fluid stream. As the fluid moves up and across outer edge 20, the entrained fresh air and dirt will move up through internal passage 30 and towards fluid splitter 31. Fluid splitter 31 can be seen as an annular shoulder and it functions to split the fluid into a recirculating portion which moves back into central passage 16 and a waste portion which will contain most of the dirt dust and the fresh air. The waste portion passes over the top of fluid splitter 31 and into a collection chamber 32. The collection chamber 32 is positioned above central passageway 16 and may include a removable dirt or dust bag. Excess air passes through opening 33 which contains a filter screen to allow air to exhaust while preventing any dirt or dust from doing the same. The dirt or dust which passes up through internal passage 30 is heavier than the air circulating about curved body 15 and has too much momentum to pass under fluid splitter 31. The dirt and dust therefore passes over the top of fluid splitter 31 and into dust collection chamber 32. Waste air passes through opening 33 which has a filter extending across it. Put in another way, annular blowing slot 28 blows fluid over a surface 15 of convex curvature and increasing surface area 17. In passing over this surface at high speed, adjacent air is entrained into the flow carrying with it the particulate matter to be discarded. The air plus particulate matter enters the internal passageway 30 and passes up through the passageway to annular shoulder (or fluid splitter) 31. The curve of the shoulder can be designed to be too tight (a small radius) for most of the particulate matter to curve around, the particulate matter having more weight than air. In addition, there are no air straightening vanes after the fan. The air leaving the fan spirals and a cyclone is formed in passage 30 which throws the particulate matter outwards by centrifugal action. The effect is that air curves over upper portion 18 and below fluid splitter 31 while most of the particulate matter continues in a less curved path to override and pass fluid splitter 31 and to enter into collection chamber 32. Table 1 shows a comparison between a conventional vacuum cleaner and a vacuum cleaner the subject of this invention. COMPARISON DATA CONVENTIONAL NEW "JET FAN" VACUUM CL ΞANER COANDA VACUUM CLEANER Power Consumed (watts) 1,100 454 RPM 18,000 18,000 Fan Diameter 125mm 112mm Stages 2 (two fans) 1 (one fan) Litres Air/Second 46 144 Speed at Carpet Surface 60kρh 240kph Efficiency of Fan 9.1% 70% plus Size and Weight 10kg Half of Conventional It should be appreciated that various other changes and modifications can be made to the embodiment without departing from the spirit and scope of the invention.

Claims: CLAIMS: 1. A vacuum cleaner head comprising a curved body about which fluid can circulate, the curved body having a lower portion which in use is adapted to be adjacent the area to be vacuumed, the lower portion being dimensioned to provide a lower pressure surface, the curved body also having an upper portion dimensioned to provide a higher pressure surface, fluid acceleration means to accelerate the fluid about the curved body, a fluid stream splitter in the upper portion of the curved body to split the fluid into a recirculated portion which continues to move about the curved body, and a waste portion which passes into a dust collecting chamber and is exhausted therefrom. 2. The head of claim 1, wherein the body is a toroid. 3. The head of claim 2, wherein the fluid acceleration means is in the central passageway defined by the toroid. 4. The head of claim 3, wherein the fluid acceleration means is in a lower portion of the central passageway. 5 The head of claim 3, wherein the fluid acceleration means is a fan. 6. The head of claim 5, wherein the fan is driven by a motor, the motor being positioned in the central passageway and above the fan. 7. The head of claim 3, including a fluid blowing slot adjacent the lower portion to propel fluid over the lower pressure surface. 8. The head of claim 7, wherein the fluid splitter functions as a fluid sucking slot. 9. The head of claim 8, wherein the fluid acceleration means is positioned below the fluid splitter and above the fluid blowing slot. 10. The head of claim 9, wherein the dust collection chamber is above the central passageway and includes an exhaust vent to exhaust the waste portion of the fluid . 11. The head of claim 10, where the fluid is air.

Inventors: DAY TERENCE ROBERT, DAY, TERENCE, ROBERT
Applicants: DAY TERENCE ROBERT, MAGIVIEW PTY LTD, DAY, TERENCE, ROBERT, MAGIVIEW PTY. LTD.
Application year: 1996
Main classification: A47L9
IPC codes: A47L9, B01D45