DK177736B1

DK177736B1 - Cleaning device using cavitation

Info

Publication number: DK177736B1
Application number: DK201300340A
Authority: DK
Inventors: Knud Erik Westergaard
Original assignee: Knud Erik Westergaard
Priority date: 2013-06-04
Filing date: 2013-06-04
Publication date: 2014-05-12
Also published as: WO2014194913A1

Abstract

A cleaning device (1) is disclosed, comprising a water duct having an inlet end and an outlet end, a cavity producing element (8, 9) arranged at least partly within the water duct to perform a rotational and/or reciprocating high-speed motion for creation of cavities in water flowing through the water duct from its inlet end to its outlet end, and a nozzle ( 4) arranged for discharging the water from the cleaning device including the cavities formed therein by the cavity producing element. Furthermore, a method is disclosed for cleaning a surface, said method comprising the steps of producing cavities within a flow of water by performing a rotational and/or reciprocating high-speed motion of a cavity producing element (8, 9) within a water duct through which the water flows, and discharging the water including the cavities formed therein from the water duct onto the surface to be cleaned.

Description

DK 177736 B1 i

Cleaning device-using cavitation

The present invention relates to a cleaning device, the faction of which mftttos to the use of cavitation In water.

5

Background of the invention

Cavitation is the fonnation ami then immediate implosion of cavities in a liquid, these cavities being small liquid-free zones ("bubbles"). Cavitation is the 10 consequence of forces acting open the liquid. It usually occurs when a liquid is subjected to rapid changes of pressure that cause the formation· of cavities where the pressure is relatively low.

Inertial cavitation is the process, is which the rapid col lapse of a babble in a liquid 15 produces a shock wave, whereas non-inertia! cavitation is a process, is winch a bubble In a fluid is forced to oscillate in size or shape due to some form of energy input, such as an acoustic field.

The use of aonrieotial cavitation in water for cleaning purposes is known within the 20 ait, for Instance in the form of ultrasonic cleaners, is which the oscillations of the cavities are controlled by means of an ultrasonic energy field. This form of cavitation is oåen used for the cleaning of delicate materials,, such m silicon wafers. Hie production of such ultrasonic cleaners is relati vely costly, 25 Other cleaning devices, such as some Mgh»pressure cleaners, use inertial cavitation for deasisg purposes. In such devices, water under high pressure and at high speed is directed along or through suitably formed physical structures, behind which the necessary low pressure to form cavities in the water is created due to turbulence in the flow, 30 DK 177736 B1 2 'The production and use of high-pressure cleaners, however, is known to entail a number of disadvantages such as, for instance, relatively high production costs, the need of access to a power socket for the supply of electricity to the device through a power cord and tire necessary safety considerations related to the combination of 5 water and high-voltage electricity within the device. Furthermore, it is often necessary to add chemicals to the water in order to obtain the desired effect of the cleaning, and the user is not only subject to a recoil impact from the device but also to inhalation of a mist containing not only water but also dirt and, if used, chemicals, 10 Brief description) of the invention

It is an object of the present, invention to provide a cleaning device Ming cavitation without the above-mentioned disadvantages of devices already known in the art.

15 The present invention relates to a cleaning device comprising a water duet having an inlet end and an outlet end, a cavity producing element arranged at least partly within the water duct to perform a rotational and/or reciprocating high-speed motion for creation of cavities in water flowing through the water duct from its inlet end to its outlet end, and a nozzle arranged for discharging the water from the cleaning device 20 including the cavities formed therein by the cavity producing element.

The invention has surprisingly shown to be able to perform cleaning of at least the same efficiency as other cleaning devices known in die art, which use cavitation, although it is a much simpler construction than such known devices and, therefore, 25 can he produced at significantly lower costs.

In an embodiment of the invention, the motion of the cavity producing element is driven by a battery-driven electric motor.

30 In an embodiment of the invention, the electric motor is driven by a replaceable and/or rechargeable battery.

DK 177736 B1 3

The ose of a battery-driven electric motor means that the power cord, which is necessary tor other cleaning devices known is the art, which use cavitation, can be avoided. Thus» the use of die present ittvendøa does sot depend on access to high-5 voltage power and the device can be used anywhere.

In an embodiment of the invention, the cleaning device farther comprises a regulator for controlling the speed of the motion of the cavity producing element, 10 The opportunity to regulate the speed of the motion of the cavity producing element means that the cleaning efficiency of the cleaning device can he controlled, so that the cleaning device can be used for cleaning robust surfaces as well as more vulnerable surfaces, ! 5 1« an embodiment of ibe Invention, the cavity producing element is arranged to be rotated at rotational speeds of more than 5,000 rpm, preferably more than 10,000 rpm, most preferred more than 20,000 rpm.

Rotational speeds within these ranges have proven to result in cleaning efficiencies 20 of the cleaning device snliable for cleaning robust surfaces as well as more vulnerable surfaces.

In an embodiment of the invention, the cavity producing element is a rotor comprising a longitudinal rotor shaft with one or mom rotor vanes extending is 25 substantially radial directions from the rotor shah.

In an embodiment of the Invention, the angle between any two neighbouring directions, into which one or more rotor vanes extend front the rotor shaft, is substantially the same.

30 DK 177736 B1 4

The ase of a rotor shaft from which rotor ws extend In substantially radial 'directions a cavity prudaemg element has proven to result in a stable and reliable function of the cleaning device.

5 In an embodiment of the invention, the cavity producing element is held in positron by one or more water lubricated bearings.

The use of water lubricated bearings substantially reduces the wear on the cavity producing element during operation of the cleaning device.

10

In m embodiment of the invention, the cavity producing element is arranged So he able to operate with water flowing into the inlet end of the water duct at a water pressure of less than 10 bar, preferably less than 5 bar, I S The cleaning device being able to operate at water pressures so low means that die water supply to the cleaning device can simply consist in a hose connected to an ordinary tap and that the leeoii Impact and the mist containing dirty water and, if chemicals are used, chemical rests known from the use of Mgh-pressute cleaners is avoided, 20

In an aspect of the invention, it relates to a method for cleaning a surface, said method comprising the steps of producing cavities within a flow of water by performing a rotational and/or reci procating high-speed motion of a cavity producing element within a water duct through which the water flows, and discharging the 25 water including the cavities formed therein from the water duct onto fee surface to be cleaned.

In an embodiment of the invention, the pressure of the water entering the water duct is less fears 10 bar, preferably less than 5 bar.

30 DK 177736 B1 5

The figures la the following, a few exemplary embodiments of the invention is described in further detail with reference to the figures, of which 5

Fig, I is a schematic cross-sectiorsa! view of a cleaning device according to an embodiment of the invention,

Figs, 2a-2e are schematic cross-sectional views of rotors of cleaning devices 10 according to three different embodiments of the invention, respectively,

Figs, 3-8 are schematic cross-sectional views of the outlet part of cleaning devices according to six different embodiments of the invention, respectively, 15 Fig, 9 is a schematic side view of a bearing of a cleaning device according to an embodiment of the invention, and

Fig. 10 is a schematic side view of a part of a rotor shaft of a cleaning device according to m embodiment of the in vention, 20

Detailed description of the invention

Fig, 1 shows a schematic cross-sectional view of a cleaning device 1 according to an embodiment of the invention, 25

Basically, the shown embodiment can be divided into a handle part 2, a barrel part 3 and a nozzle 4, The handle part 2 is connected to a first end of the barrel part 3 and the nozzle 4 is placed at the other end of the barrel part 3, A water duct extends throughout the cleaning device 1 from its inlet end at the bottom of the handle part 2 30 through the handle part 2 and the barrel part 3 to Its outlet end at the nozzle 4, DK 177736 B1 6 , The figure illustrates how the water supply to the cleaning device 1 can simply consist In a water hose 5 connected to an ordinary tap (not shown). This is due to the fact that the cleaning device 1 is able to operate at very low water pressures like the ones provided in customary domestic water supplies. In the illustrated embodiment 5 of tbe invention, a water filter 6 is arranged at the inlet end of the water dnct between the water hose 5 and the handle part 2 of the cleaning device.

A water valve 7 is arranged within the water dnct for stopping the flow of water through the water duct, when the cleaning device 1 is not operating, in the illustrated 10 embodiment, the water valve 7 is placed in the part of the water duct passing through, the handle part 2 of the cleaning device 1 but, in other embodiments, the wafer valve 7 can be placed anywhere in the water duct.

in the illustrated embodiment, a cavity producing element in the form of a rotor S, 9 15 extends throughout the barrel part 3 from an electric motor 10 arranged within the handle pan 2 of the cleaning device 1 to the nozzle 4 thereof In some embodiments of the invention, the electric motor 10 is air cooled, whereas, in other embodiments, it is water cooled.

20 The illustrated rotor consists of a rotor shaft 8 with, one or more rotor vanes 9 extending in substantially radial directions therefrom. The dimensions of the rotor shaft 8 and the rotor vanes 9 depend on the desired capacity of the cleaning device 1. Typically, the diameter of the rotor shaft 8 Is a few millimetres, such as about 5 mm.

25 to the illustrated embodiment, the rotor is held in place by three bearings, namely a rear rotor bearing 11 placed at the end of the rotor, which is connected to the electric motor 10, an. intermediate rotor hearing 1.2 placed approximately halfway through the barrel part 3 of the cleaning device 1, and a front rotor beating 13 placed near the nozzle 4. A gasket 14 is arranged behind the rear rotor bearing 11 to protect the 30 electric motor 10 from water and moisture.

DK 177736 B1 7

The Illustrated embodiment of the invention is provided with a device activation handle 15, which is operated similar to a trigger of a firearm. When the device activation handle I S Is pressed backwards, the water valve 7 is opened and an electric switch 16 switches on the electric motor 10 for operation of the cleaning 5 device I. When on the other band, the device activation handle 15 is released again ibr stopping the operation of the cleaning device l, the water valve 7 Is closed and the electric switch 16 switches oft'the electric motor 10,

An electric battery I? (preferably In the form of a replaceable and/or rechargeable 10 battery, such as a lithium battery) for driving the electric motor 10, and a regulator 18 for regulating the rotational speed of the rotor 8,9 are schematically illustrated under the barrel part 3 of the cleaning device 1 In Fig, L In other embodiments, however, the battery 17 and/or the regulator IS can be placed at other positions within the cleaning device 1, hs some embodiments of the invention, the cleaning device 1 can 15 be provided with a charging station (not shown) for die battery 17 similar to the ones provided for rechargeable electric screwdrivers and the like.

During operation of the cleaning device 1, the water valve 7 is open and water Hows from the water hose 5 through the water duct to the nozrite 4. The electric motor 10 is 20 running, causing the rotor to rotate at very' high speed, typically at several thousand rounds per minute. In other embodiments of the invention, this rotational motion of a cavity producing element 8,9 e-an be replaced by or combined moth vibrational and/or reciprocation motions, 25 Under-pressure behind die fast-moving vanes 9 of the rotor causes cavities f‘bubbles'") to be formed in die water as it flows along the rotating «her, These cavities leave the cleaning device 1 with the water through the nozzle. 4 When the water with the cavities meets a surface, shock forces related to the sodden, implosion of the cavities loosen dirt from the surface and Mil bacteria on the surface, whereby 3D not only a cleaning effect but also a disinfectant effect of the invention is achieved without the use of any chemicals.

DK 177736 B1 8

The dimensions of the cleaning device i vary depending on the desired dealing efficiency, hut typical embodiments are similar in size to the handheld part of common high-pressure cleaners for private or professional use.

5

Figs. 2a«2c are schematic cross-sectional views of rotors of cleaning devices 1 according to three different embodiments of the invention, respectively.

As illustrated in these figures, the rotor vanes 9 may extend in a number of different 10 radial directions from the rotor shaft 8. In the illustrated embodiments, the rotor vanes 9 extend in four, two and three different directions, respectively. In other embodiments, however, the rotor vanes 9 can extend in more than four different radial directions, or they can extend in directions that are not radial In relation to the rotor shaft.

15

For the sake of balance of foe rotor 8,9 during operation of the cleaning device 1, it is advantageous, if the angle between any two neighbouring directions, into which one or more rotor vanes 9 extend from the rotor shaft, is substantially the same. For instance, the angle between any two neighbouring directions is 90° in Fig, 2a, 18(1* 20 in Fig, 2b and 120* in Fig, 2c,

Furthermore, also for the sake of balance, it is advantageous if at least approximately the same number of rotor vanes 9 extend In each of the directions, such as every second or every fourth vane 9 extending in a given direction in Fig. 2a, every second 25 vane 9 extending in a given direction in Fig. 2b and every third vane 9 extending in a given direction in Fig. 2c.

Figs. 3-7 are schematic cross-sectional views of foe outlet part of cleaning devices I according to five difrerent embodiments of the invention, respectively, 39 DK 177736 B1 9

Mp, 3-6 ikstrate how the shape of the rotor vanes 9 can vary from one etobodhnent 1© the other, the cioss-sfctsonof the vaoes 9 being wide square!» Fig, 3, narrow square k Fig* 4, triangular in Mg. 5 and sinusoidal in Fig, 6, 5 Fig, ? illustrates schematically that» whereas the røtor vanes 9 are subs^tiaily equally distributed along the full length of the rotor shall S in some embodiments of the invention as illussmted in Mgs, i and 3-6, they may he confined to a part of the rotor shaft 8, preferably the part nearest the nozzle 4, in other embodiments as illustrated in Fig. 7, It is to he understood that the different distributions ofthe rotor 10 vanes 9 along the rotor shaft 8 can be combined wi th any of the shapes of vanes 9 illphakd In Tip; 3^6 or with other shapes not illustrated.

The rotor vanes 9 can he made from a variety of suitable materials, such as for instance aluminium or synthetic rubber. In preferred embodiments, the rotor S, 9 is 15 exchangeable so that different rotors §, 9 can be used for different cleaning purposes and worn out rotors 8, 9 can be exchanged.

Fig. 8 illustrates schematically how, in some embodiments ofthe cleaning device 1, a number of mw&tå-pomimg protrusions 23 can M amanged in at least a part ofthe 20 barrel part 3 thereof. Properly arranged, such protrusions 23 can have a stabilMng effect on She water jet leavmg the cleaning device 1 by reducing die rotational effect on the water cansed by the roMion of the rotor 8, f.

Fig, 9 Is a schematic side view of a hearing I1* 12,13 of a cleaning device 1 25 according to an embodiment of the invention.

In order to allow the Sow of water through the water duct to pass by the bearing I T 12,13, It is ad vantageously mounted with a number of spokes 19 connecting the bearing II, 12,13 to a mounting ring 20 fitting the inside ofthe barrel part 3 of the 30 clearing device 1, in this way, the water can pass between the bearing II, 12,13 and the mourning ring 20 mthout meeting any significant resistance. Ibis resistance may DK 177736 B1 10 be reduced even, further by tapering the spokes 19 in the direction facing upstream the water flow (sot shown).

An advantageous water lubrication of the bearings 11,12,13 can be obtained, for 5 instance, by providing the hearing 11,12,13 with some inward pointing protrusions 21 as indicated schematically in Fig. 9 and/or with providing the part of the rotor shaft 8, which Is to be placed, inside the bearing 11,12,13, with a number of countersunk grooves 22 as indicated schematically in Fig, 10. Correctly applied, such features causes the formation of a water film between the rotor shaft S and the 10 bearing U, 12» 13, significantly reducing the Motion there between and the wear on the rotor shaft 8 and the bearings 11,12,13 during use of the cleaning device 1. This principle for obtaining water lubrication is known, for instance, from the field of propeller shafts from the maritime industry, 15 DK 177736 B1 11

List øf reference »embers L Cleaning device 2, Handle part of cleaning device S 3. Band pari of denning device 4. Nozaie 5. Water hose 6. Waier ilter 7. Waier valve 10 8. Rotor shaft 9» Rotor vane 10. Electric røøtør 11. Rear rotor bearing 12. Intermediate rotør bearing 15 13. Front rotor bearing 14. Gasket 15. Device activation batsdie 16. Electric switch for motor 17. Battery 20 18. Regulator for rotational speed of rotor 19. Spoke of bearing 20. Mounting ring for beating 21. Inward-pointing protrusion in bearing 22. Coimiersnolt groove in rotor shaft 2$ 23, Inward-pointing protrusions in barrel part

Claims

2. Rengøiingsanørdaing ifølge krav 1, hvor bevægelsen af det kavitetsprodueerende element drives af en batteridrevet elektrisk motor (10). 20 3, Rengøringsanordnlng ifølge krav 2, hvor den elektriske motor dri ves af et udskifteligt og/eller genopladeligt batteri (17).A cleaning device according to claim 1, wherein the movement of the cavity producing element is driven by a battery-operated electric motor (10). 20, A cleaning device according to claim 2, wherein the electric motor is powered by a replaceable and / or rechargeable battery (17).

4. Rengøringsanordning ifølge et hvilket som helst af de foregående tov, som yderligere omfatter en regulator (IS) til styring af hastigheden af det 25 kavitetsprodueerende elements bevægelse.A cleaning device according to any of the preceding ropes, further comprising a regulator (IS) for controlling the rate of movement of the cavity producing element.

5. Rengøringsanordning ifølge et hvilket som helst af de .foregående krav, hvor det kavitetsprodneerende element er arrangeret til at blive roteret med rotationshastigheder på mere end 5,000 omdrejninger pr. minut, fortrinsvis 30 mere end 10.000 omdrei runger pr. minut, mest Ibrtriusvis mere end 20,000 Λ omdrejninger pr, minut. DK 177736 B1 2A cleaning device according to any one of the preceding claims, wherein the cavity-producing element is arranged to be rotated at rotational speeds of more than 5,000 rpm. preferably more than 10,000 revolutions per minute. more than 20,000 Λ revolutions per minute per minute. DK 177736 B1 2

6, Rengøringsimordning ifølge et hvilket som helst af de foregående krav, hvor det kavltetsprodneereade element er en rotor, der omfatter en langsgående rotomksel (S) med en eller flere rotorvinger (9), der itostrøkker sig ii. det S væsentlige radiale retninger fra røtorakslen.A cleaning device according to any one of the preceding claims, wherein the catenary protruding element is a rotor comprising a longitudinal rotor shaft (S) having one or more rotor blades (9) extending to it ii. the S essential radial directions from the rotor shaft.

7, Ren^ringsanordning Ifølge tav 6, hvor vinklen mellem hvilke som helst to aabøretænger, i hvilke en eller Sere rotorvinger ndstrækker sig fra røtoraksleo, er i det væsentlige den samme, 107, Cleaning Device According to Table 6, wherein the angle between any two opener tongs in which one or more rotor blades extend from the rotor shaft is substantially the same.

1, Renpaingsanordning ifølge et hvilket mm helst af de foregående krav, hvor det kavlietsprodneerends element holdes pi plads af et eller flere vandsmnrte lejer, 15 9, Rengøringsanørdning ifølge et hvilket som’ helst af de foregående krav, som er arrangeret til at være i stand til at føngere med vand strømmende ind i vmKSkanalens indlobsende ved et vandtryk på mindre end 10 bar, fortrinsvis mindre end 5 bar* 20 10*. Fremgangsmåde ti rengøring af an overflade, hvilken frentgangsmåde omfatter trinene til: ~ at producere kaviteter i en strøm af vand ved at ødføie en roterende og/eller frem* og tilbagegående højhastigbedsbevægelse af et 25' kavitetsprodaeerende element (S, 9} inden i en vandkanal, gennem hvilkeri vandet strømmer, og ~ af ndiede vandet indeholdende kaviteterne, der er dannet deri, ffa yaadkaætlea på overfladen, der skal rengøres, 30 DK 177736 B1 31, A cleaning device according to any one of the preceding claims, wherein the element of the cavity product is held in place by one or more watertight bearings, Cleaning device according to any one of the preceding claims, which is arranged to be capable of for capturing with water flowing into the entrance end of the vmKS channel at a water pressure of less than 10 bar, preferably less than 5 bar * 20 10 *. A surface cleaning method comprising the steps of: ~ producing cavities in a stream of water by applying a rotating and / or forward * and reciprocating high velocity movement of a 25 'cavity producing element (S, 9} within a water channel , through which the water flows, and from the water containing the cavities formed therein, ffa yaadkaætlea on the surface to be cleaned, 30 DK 177736 B1 3

11. Fremgangsmåde ifølge krav 10» hvor trykket af vandet, der kommer ind i vandkaoakn er mindre end 10 bar, fortrinsvis mindre end 5 bar.A method according to claim 10 wherein the pressure of the water entering the water ***e is less than 10 bar, preferably less than 5 bar.