GB2516652A

GB2516652A - Cleaning surfaces

Info

Publication number: GB2516652A
Application number: GB1313463.0A
Authority: GB
Inventors: Kevin Windham Hunt
Original assignee: ICING TECHNOLOGIES Ltd DE
Current assignee: ICING TECHNOLOGIES Ltd DE
Priority date: 2013-07-27
Filing date: 2013-07-27
Publication date: 2015-02-04
Also published as: GB201313463D0

Abstract

An apparatus and method suitable for cleaning surfaces, though more particularly for de-icing a surface for example, the wings of an aircraft. The apparatus having a cleaning head 1 comprising, a plenum chamber 2 in fluid communication with a cleaning cavity 3; and an ultrasonic generator 6 with a vibrating head located in the cleaning cavity. A solvent fluid 4 is metered into the plenum chamber which, when full of the fluid, abuts the surface 10. The fluid is ejected into the cleaning cavity via feeder nozzles. A vibration generator, at a predetermined distance from the surface, vibrates the fluid within the cleaning cavity and may also flex the surface. The cleaning or de-icing action is a synergy of the solvent acting on the foreign material on the surface and agitation by the vibrating solvent.

Description

CLEANING SURFACES

This specification relates to apparatus and methods of using it I them for cleaning surfaces, whether the surfaces are covered by frost, ice, grime or any other contaminant.

There are many requirements for cleaning surfaces, for example, removing the grime of centuries of atmospheric pollution from cathedrals, civic buildings, etc.; here, the key requirement is not to damage the fabric of the buildling, which may be hundreds of years old. Another, and very important example is de-icing the wings, tail-plane and fuselage of aircraft at airports; here, speed of operation is important as takes off are scheduled and snow may actually be falling while de-icing is in progress.

In de-icing operations, a de-icing fluid is usually provided in a tanker and pumped to an operator(s) on an elevated platform(s), whence it is directed onto the aircraft. The operators are usually very experienced and direct the fluid carefully and as economically as practicable. However, when speed is required, there is always some spray that goes astray. Additionally, there will be occasions when ice may have been freed from the wing surface but is on an essentially horizontal part of the wing and so does not slide off. Under these circumstances, the operator will direct further fluid onto that ice to melt it fully, i.e. he I she will have to use excess fluid in the process. While there is a cost for wasted fluid, another factor is the fluid running into the drains and the additional costs to separate this from normal waste water.

Also, spraying normally produces a mist partly obscuring visibility and this can be a further problem for the operator.

De-icing fluid is normally based on organic solvents, which have a vapour pressure even at sub-zero temperatures (<0°C) and this can affect sensitive people. At major airports, the operators usually have enclosed cabins from which to direct the fluid sprays but this is not always the case on smaller airfields. Additionally, there may be ground staff loading baggage and servicing aircraft on adjacent stands and they can be subject to quite high concentrations of vapour, especially if they are downwind of the de-icing operation.

Thus, there is strong need for an apparatus and a method to use it to de-ice aircraft quickly with the minimum quantity of de-icing fluid and to apply the principle to other forms of surface cleaning. It is also desirable to limit the extent of airborne spray for the reasons cited above.

According to the invention, there is provided apparatus for cleaning a surface comprising:-i) a surface to be cleaned; ii) a cleaning fluid having appropriate properties for the particular cleaning operation; iii) a means to produce a vibration at an appropriate frequency(ies); iv) a distribution means to apply the cleaning fluid onto and over the surface and direct the vibrations towards the surface; v) a means to move the distribution means progressively over the surface from a part that has been cleaned to a part that is yet to be cleaned; and vi) a means to discharge spent cleaning fluid and foreign material from the cleaned surface away from the cleaned part of the surface; characterised in that the distribution means moves progressively over the surface applying the cleaning fluid essentially uniformly and directly onto the surface and that the means of vibration is directed towards the surface so that actions of the cleaning fluid and vibration combine to produce synergy and free foreign material from the surface and that the discharge means carries the removed foreign material and used cleaning fluid away leaving a cleaned surface.

According to a first variation of the apparatus of the invention, the surface to be cleaned is part of an aeroplane.

According to a second variation of the apparatus of the invention, the surface to be cleaned is part of a building or structure.

According to a third variation of the apparatus of the invention, the cleaning fluid includes an organic substance.

According to a fourth variation of the apparatus of the invention, the cleaning fluid includes water.

According to a fifth variation of the apparatus of the invention, the vibration generates vibrational movement in the cleaning fluid.

According to a sixth variation of the apparatus of the invention, the vibration is at I close to a resonant frequency of vibration of a constituent of the cleaning fluid.

According to a seventh variation of the apparatus of the invention, the vibration generates vibrational flexing of the surface being cleaned.

According to an eighth variation of the apparatus of the invention, the distribution means includes a plurality of points to apply the cleaning fluid to the surface and a plurality of sources of vibration.

According to a ninth variation of the apparatus of the invention, the distribution means is maintained essentially at a predetermined distance from the surface to be I being cleaned.

According to a tenth variation of the apparatus of the invention, the means to maintain the distribution means at an essentially predetermined distance from the surface includes mechanical means.

According to an eleventh variation of the apparatus of the invention, the means to maintain the distribution means at an essentially predetermined distance from the surface includes electrical and I or electronic means.

According to a twelfth variation of the apparatus of the invention, the means to maintain the distribution means at an essentially predetermined distance from the surface includes manual control.

According to a thirteenth variation of the apparatus of the invention, the means to maintain the distribution means at an essentially predetermined distance from the surface includes automatic control.

According to a fourteenth variation of the apparatus of the invention, the distribution means is designed so that a layer of cleaning fluid builds up between the distribution means and the surface being cleaned so that the effect of the vibration creates an ultrasonic cleaning action in the layer of cleaning fluid.

According to a fifteenth variation of the apparatus of the invention, means are provided to change the profile of the distribution means to maintain the distribution means at the essentially predetermined distance from the surface as it moves over the surface to be cleaned (contour I profile following).

According to a sixteenth variation of the apparatus of the invention, means are provided to monitor the quantity of fluid between the distribution means and the surface to be cleaned and adjust the fluid flow rate through the various points on the distribution means to maintain the essentially predetermined distance between the distribution means and the surface full of fluid.

According to a seventeenth variation of the apparatus of the invention, means are provided to monitor the quality of vibration in the fluid between the distribution means and the surface to be cleaned and adjust the vibrators as appropriate to maintain vibration at the predetermined level.

According to an eighteenth variation of the apparatus of the invention, the means to move the distribution means progressively over the surface is either manually controlled or automatically controlled or features a combination of both. is

According to a nineteenth variation of the apparatus of the invention, the means to discharge spent cleaning fluid and foreign material is from the trailing edge of the distribution means.

According to a twentieth variation of the apparatus of the invention, the means to discharge spent cleaning fluid and foreign material includes the provision of a further fluid.

According to the invention, there is provided a method for cleaning a surface comprising the steps of:-i) providing a surface to be cleaned; ii) providing a cleaning fluid having appropriate properties for the particular cleaning operation; iii) providing a means to produce a vibration at an appropriate frequency(ies); iv) providing a distribution means to apply the cleaning fluid onto and over the surface and direct the vibrations towards the surface; v) providing a means to move the distribution means progressively over the surface from a part that has been cleaned to a part that is yet to be cleaned; and vi) providing a means to discharge spent cleaning fluid and foreign material from the cleaned surface away from the cleaned pad of the surface; characterised in that the distribution means is moved progressively over the surface and applies the cleaning fluid uniformly and directly onto the surface and that the means of vibration is directed towards the surface so that actions of the cleaning fluid and vibration combine to produce synergy and free foreign material from the surface and that the discharge means carries the removed foreign material and used cleaning fluid away leaving a cleaned surface.

S According to a first variation of the method of the invention, the means of applying cleaning fluid includes spraying or squirting onto the surface to be cleaned.

According to a second variation of the method of the invention, the rates of applying fluid to the surface and the speed of movement of the distribution means over the surface are correlated so that a film of fluid is continually present between the distribution means and the surface during cleaning operations.

According to a third variation of the method of the invention, the film of fluid between the distribution means and the surface acts to provide hydrodynamic or aerodynamic lubrication to assist the movement of the distribution means over the surface.

According to a fourth variation of the method of the invention, the fluid in the film of fluid between the distribution means and the surface is caused to vibrate and also acts to transmit the vibrations from the sources of vibration to the surface.

According to a fifth variation of the method of the invention, the fluid in the film of fluid between the distribution means and the surface is caused to vibrate and also acts to transmit the vibrations to the surface causing it to vibrate or flex.

According to a sixth variation of the method of the invention, the frequency of vibration is at / near a natural frequency or resonant frequency of vibration of the fluid in the film of fluid, or of a constituent of the film of fluid, between the distribution means and the surface so that the liquid is caused to vibrate violently and I or to boil or to cavitate locally and also transmits the vibrations directly to the foreign material on the surface causing it to be removed from the surface.

According to a seventh variation of the method of the invention, a further fluid is provided to the means to discharge spent cleaning fluid and foreign material to assist in the discharging process.

In a preferred application of the design applied to a flat surface to be cleaned, a cleaning head is located at a predetermined distance from the surface and moved progressively, at a predetermined rate, over it. A cleaning fluid is sprayed onto the surface from a nozzle / plurality of nozzles (depending on the size of the surface) so that, ideally, a film of fluid fills the gap between the head and the surface. Mounted on the underside of the head is a vibrator I plurality of vibrators with, ideally, the active part of the vibrator submerged in the film of fluid. The result is that the cleaning action of the fluid's solvent(s) is I are enhanced by the vibration so that the two act together to produce synergy. The effect created is similar to that of an ultrasonic cleaning bath, with which watchmakers, jewellers and people in certain scientific laboratories are familiar.

Preferably, the frequency of vibration is chosen to cause the fluid, or a component of the fluid, to vibrate and cavitate. Cavitation is where a locally reduced pressure causes the liquid to vapourise (boil) forming small bubbles; these bubbles usually collapse violently, often generating mini-shock waves, which would be very effective in fracturing ice or hard layers of grime. The vibration may also cause flexing of a thin surface being cleaned.

Thus, the effect of the vibration will be to enhance the cleaning process. As the head moves along the surface, the fluid flows away from the trailing edge carrying the foreign material! grime I etc. with it, leaving a clean surface behind.

For a clearer understanding of the invention and to describe how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which;-Figure 1 is a cut-away perspective view of one form of apparatus of the invention; Figure 2 is a plan view of another form of apparatus of the invention; and Figure 3 is a sectional elevation of the apparatus shown in Fig. 2 along the plane AA.

In the following description, the same reference numeral is used for identical components in different Figures or for different components fulfilling identical functions.

One common example of a cleaning requirement is de-icing of aircraft at airports in severe winter conditions. Organic solvents are generally used and, while they dissolve the ice rapidly, they act from the exposed face of the ice down towards the aircraft skin, Le. they dissolve the whole thickness of the ice. If the ice could be freed from its adhesion to the skin, it could be slid off in thin sheets', i.e. the whole of the ice sheet would not have to be dissolved, saving a great deal of solvent. By employing vibration at a frequency that causes cavitation of the fluid, the icy bond with the skin may be weakened or broken and the ice may be removed as solid pieces, rather than as a melted solution.

Referring to Fig. 1, a cleaning head us shown here as a de-icing head and consists of a flexible plenum chamber 2 surrounding coupling cavity 3. An ultrasonic generator 6 is mounted centrally in head 1, which is pressed 12 against the aircraft skin 10. De-icing fluid 4 is pumped in, at a metred rate, via inlet pipe 4 to inflate plenum 2 (as shown) and exits through nozzles 5 into the coupling cavity 3. (The word inflate' is used to describe the filling of plenum 2 to distend membrane 2A, as shown (Fig. 1). Though inflate' is usually associated with filling with air or gas (and fluid 4 could be air or gas), de-icing fluids are usually liquids and inflate' is used here in the context of both a gas and a liquid.} An ultrasonic vibration generator 6 is located essentially at the centre of coupling cavity 3, i.e. on axis 3A, which is full of fluid 4. As the vibrating head 6A of generator 6 is immersed in fluid 4, the whole of the fluid 4 in cavity 3 is caused to vibrata If required a vent (not shown) is provided to release any air trapped in cavity 3 as it is essential that head 6A is in direct contact with fluid 4. Furthermore, any air bubbles in cavity 3 will act to cushion the effect of the vibration from head 6A and negate the full synergy provided by the vibration 6A to the cleaning process. Fluid 4 is pumped in at a metred rate and the excess fluid, carrying melted ice, ice particles and other foreign material removed from skin 10, leaves 9 from under the circumference 2B of plenum membrane 2k Looking at the cutaway shown in Fig. 1, it will be apparent that head 1 resembles the hovercraft principle. Though air is normally the fluid used under hovercraft, the liquid de-icer 4 acts in exactly the same way and the excess fluid leaving 9 lubricates the contact between membrane 2B and skin 10 so that head 1 may be moved laterally with the minimum of force in any direction over the plane of skin 10, i.e. due of the hydrodynamic or aerodynamic lubrication.

As fluid 4 is to melt ice, it is heated by a means (not shown) before it enters supply pipe 4.

As vibration generator 6 will be electrically powered, it will generate heat and needs to be cooled 7 via a separate fluid 7 circulating through jacket 8. To minimise confusing detail, the exit from jacket 8 is not shown. It is known that cavitation occurs in water at ambient temperatures, e.g. near ships' propellers, so with a warmed solvent, a considerable degree of cavitation will occur and the collapse of the mini-bubbles so formed will greatly impact on the ice, enhancing the rate of fracturing, removal and dissolution.

A force 12 from the supporting means (not shown) maintains head I in contact with skin 10. The combination of a metred, pumped feed 4 entering plenum 2 and thence 5 into coupling cavity 3 with limited egress 9 under membrane 28 and force 12 exerted on head 1 from the mounting means (not shown) maintains vibrating head 6A at an essentially constant distance 11 from skin 10. (Dashed line 10 is the common tangent to surfaces 2B and also represents the plane of aircraft skin 10.) Distance 11 is optimised so that the is power of vibrating head 6A is maximised in plane 10 to give the greatest cleaning effect.

Ideally, head 1 may be one of a group of seven, i.e. a central one with six others arranged in a circle around it, as a composite unit. The group of seven would be mounted on an articulated arm, the movement of which would be controlled by an operator, located in a protective cabin in an appropriate place, e.g. on a gantry giving unrestricted views of the area to be cleaned (de-iced).

Aircraft have large surface areas, eg. the aerofoil wings and a cylindrical fuselage, and the principle of the invention may be adapted to such surfaces. Fig. 2 shows an elongated form of apparatus 19, in which a series of square coupling chambers are aligned side-by-side between longitudinals 13 and 14 and cross pieces 15. (The membranes 2A covering the coupling chambers are numbered but not the chambers 3 underneath, as they are not visible in Fig. 2.) The Fig. 3 sectional view shows that cross pieces 15 have a triangular section, like that of a car's windscreen wiper, with the apex touching the surface being cleaned, i.e. skin 10. Like cross pieces 15, longitudinals 13 and 14 would also have a triangular section, but this is not shown in Figs. 2 or 3.

Longitudinals 13, 14 and cross pieces 15 would be mounted in an articulated manner similar to that of windscreen wipers on cars. This form of mounting allows the wiper blade, e.g. 15, to flex between the vertical and horizontal curvatures of the windscreen and a similar mounting arrangement would accommodate aerofoil sections and the curvatures of the fuselage. Members 13, 14 and 15 define chambers 3 and retain fluid 4 therein.

Automatic distance sensors, e.g. laser means (not shown) would operate via the articulated mountings to maintain clearances 11 essentially constant. Cleaning means 11 would be moved 18 at a predetermined speed and the melted ice I detached pieces of ice I used de-icing fluid 9 discharged under longitudinal 14. If there was a risk of discharge 9 S re-freezing on the (essentially horizontal) wing after cleaner 19 had moved on 18, a manifold 16 could be provided with exit holes 17 through which air could be passed to blow ice and fluid 9 off the wing 10.

Where external ribs, etc. run across the wing, the operator would lift cleaner 10 over the obstruction and set it to continue cleaning beyond this point. Any ice that was not removed would be dealt with by a cleaning head 1, controlled directly by the operator. In this way, large sections of the aircraft could be cleaned 19 automatically in a pm-programmed manner and awkward areas cleaned directly by the operator.

Where buildings, etc. have to be cleaned, apparatus 19 may be used, with suitable cleaning fluids, for lame essentially flat areas and appropriately-sized individual heads 1 used manually for cleaning, statues, fluted columns, etc. The invention uses the synergy between a cleaning fluid and causing that fluid to vibrate to enhance the cleaning effect. This is known on a very small scale, e.g. in watchmaking, but not on an industrial scale, where the novelty resides in the application of the principle and the methods of scaling it up. When the fluid is vibrated, it ads on the foreign material at the molecular level, pulling and pushing until the grime is released from the substrate. Once this has happened, the agitated-solvent movement moves the grime particle away in to the bulk of the solution, allowing more solvent to reach lower layers of grime.

In the case of melting ice, the organic solvent would not only dissolve the surface layer but break up the boundary layer of melt water, which would have formed, to allow fresh solvent to reach the ice below. If the frequency of vibration was able to cause flexing of skin 10, this would weaken the ice bond. However, cavitation would be the major factor, generating incipient cracks, into which solvent would flow, and fracturing ice. The vibrating liquid would also move the ice particles away from the surface and, while these might fully melt subsequently, it might also allow the speed of movement 18 to be increased so that un-melted particles could be discharged 9. Increasing the speed 18 would shorten the de-icing time, saving time, fluid and money.

Where buildings are being cleaned, water-based solvents are normally used. lithe vibration used was at the frequency used in microwave ovens, this would cause internal vibration within the water molecules, possibly leading to boiling. If, say, two generators 6 were used together and could focus their energies at a small area on tangent 10 (Fig.1), the water there might boil locally. If water had penetrated underneath the grime layer, the increase in volume as it turned into vapour could lift areas of grime away from the stonework below. (Tests would have to be done to ensure that any boiling action did not damage the fabric of the building.) Another point is that most substances are more soluble in warm water that in cold, so that even a small degree of warming could be beneficial to grime removal and increase the cavitation aspect.

The principle and method of the disclosure have many other applications all falling within the scope of the invention.

Claims

Claims:- 1. Apparatus for cleaning a surface comprising:-i) a surface to be cleaned; ii) a cleaning fluid having appropriate properties for the particular cleaning operation; iii) a means to produce a vibration at an appropriate frequency(ies); iv) a distribution means to apply the cleaning fluid onto and over the surface and direct the vibrations towards the surface; v) a means to move the distribution means progressively over the surface from a part that has been cleaned to a part that is yet to be cleaned; and vi) a means to discharge spent cleaning fluid and foreign material from the cleaned surface away from the cleaned part of the surface; characterised in that the distribution means moves progressively over the surface applying the cleaning fluid essentially uniformly and directly onto the surface and that the means of vibration is directed towards the surface so that actions of the cleaning fluid and vibration combine to produce synergy and free foreign material from the surface and that the discharge means carries the removed foreign material and used cleaning fluid away leaving a cleaned surface.
2. Apparatus for cleaning a surface as claimed in claim 1, wherein the surface to be cleaned is part of an aeroplane.
3. Apparatus for cleaning a surface as claimed in claim 1, wherein the surface to be cleaned is part of a building or structure.
4. Apparatus for cleaning a surface as claimed in claims 2 or 3, wherein the cleaning fluid includes an organic substance.
5. Apparatus for cleaning a surface as claimed in claims 2 or 3, wherein the cleaning fluid includes water.
6. Apparatus for cleaning a surface as claimed in any preceding claim, wherein the vibration generates vibrational movement in the cleaning fluid.
7. Apparatus for cleaning a surface as claimed in claim 1, wherein the vibration is at I close to a resonant frequency of vibration of a constituent of the cleaning fluid.
8. Apparatus for cleaning a surface as claimed in claim 7, wherein the vibration generates vibrational flexing of the surface being cleaned.
9. Apparatus for cleaning a surface as claimed in any preceding claim, wherein the distribution means includes a plurality of points to apply the cleaning fluid to the surface and a plurality of sources of vibration.
10. Apparatus for cleaning a surface as claimed in claim 9, wherein the distribution means is maintained essentially at a predetermined distance from the surface to be I being cleaned.
11. Apparatus for cleaning a surface as claimed in claim 10, wherein the means to maintain the distribution means at an essentially predetermined distance from the surface includes mechanical means.
12. Apparatus for cleaning a surface as claimed in claim 10, wherein the means to maintain the distribution means at an essentially predetermined distance from the surface includes electrical and I or electronic means.
13. Apparatus for cleaning a surface as claimed in claims 11 or 12, wherein the means to maintain the distribution means at an essentially predetermined distance from the surface includes manual control.
14. Apparatus for cleaning a surface as claimed in claims 11 or 12, wherein the means to maintain the distribution means at an essentially predetermined distance from the surface includes automatic control.
15. Apparatus for cleaning a surface as claimed in any preceding claim, wherein the distribution means is designed so that a layer of cleaning fluid builds up between the distribution means and the surface being cleaned so that the effect of the vibration creates an ultrasonic cleaning action in the layer of cleaning fluid.
16. Apparatus for cleaning a surface as claimed in claim 15, wherein means are provided to change the profile of the distribution means to maintain the distribution means at the essentially predetermined distance from the surface as it moves over the surface to be cleaned (contour! profile following).
17. Apparatus for cleaning a surface as claimed in any preceding claim, wherein means are provided to monitor the quantity of fluid between the distribution means and the surface to be cleaned and adjust the fluid flow rate through the various points on the distribution means to maintain the essentially predetermined distance between the distribution means and the surface full of fluid.
18. Apparatus for cleaning a surface as claimed in any preceding claim, wherein means are provided to monitor the quality of vibration in the fluid between the distribution means and the surface to be cleaned and adjust the vibrators as appropriate to maintain vibration at the predetermined level.
19. Apparatus for cleaning a surface as claimed in any preceding claim, wherein the means to move the distribution means progressively over the surface is either manually controlled or automatically controlled or features a combination of both.
20. Apparatus for cleaning a surface as claimed in any preceding claim, wherein the means to discharge spent cleaning fluid and foreign material is from the trailing edge of the distribution means.
21. Apparatus for cleaning a surface as claimed in claim 1, wherein the means to discharge spent cleaning fluid and foreign material includes the provision of a further fluid.
22. A method for cleaning a surface comprising the steps of:-i) providing a surface to be cleaned; ii) providing a cleaning fluid having appropriate properties for the particular cleaning operation; iii) providing a means to produce a vibration at an appropriate frequency(ies); iv) providing a distribution means to apply the cleaning fluid onto and over the surface and direct the vibrations towards the surface; v) providing a means to move the distribution means progressively over the surface from a part that has been cleaned to a part that is yet to be cleaned; and vi) providing a means to discharge spent cleaning fluid and foreign material from the cleaned surface away from the cleaned part of the surface; characterised in that the distribution means is moved progressively over the surface and * 35 applies the cleaning fluid uniformly and directly onto the surface and that the means of vibration is directed towards the surface so that actions of the cleaning fluid and vibration combine to produce synergy and free foreign material from the surface and that the discharge means carries the removed foreign material and used cleaning fluid away leaving a cleaned surface.
23. A method for cleaning a surface, as claimed in claim 22, wherein the means of applying cleaning fluid includes spraying or squirting onto the surface to be cleaned.
24. A method for cleaning a surface, as claimed in claims 22 or 23, wherein the rates of applying fluid to the surface and the speed of movement of the distribution means over the surface are correlated so that a film of fluid is continually present between the distribution means and the surface during cleaning operations.
25. A method for cleaning a surface, as claimed in any claim 22-24, wherein the film of fluid between the distribution means and the surface acts to provide hydrodynamic or aerodynamic lubrication to assist the movement of the distribution means over the surface.
26. A method for cleaning a surface, as claimed in claim 22-25, wherein the fluid in the film of fluid between the distribution means and the surface is caused to vibrate and also acts to transmit the vibrations from the sources of vibration to the surface.
27. A method for cleaning a surface, as claimed in claim 26, wherein the fluid in the film of fluid between the distribution means and the surface is caused to vibrate and also acts to transmit the vibrations to the surface causing it to vibrate or flex.
28. A method for cleaning a surface, as claimed in claim 27, wherein the frequency of vibration is at I near a natural frequency or resonant frequency of vibration of the fluid in the film of fluid, or of a constituent of the film of fluid, between the distribution means and the surface so that the liquid is caused to vibrate violently and / or to boil or to cavitate locally and also transmits the vibrations directly to the foreign material on the surface causing it to be removed from the surface.
29. A method for cleaning a surface, as claimed in claim 22-28, wherein a further fluid is provided to the means to discharge spent cleaning fluid and foreign material to assist in the discharging process.
30. Apparatus and method for cleaning a surface, as described in and by the above statement with reference to the accompanying drawings.