Method and Apparatus for Treating a Surface

This invention relates to methods and apparatus for treating surfaces. More particularly, but not exclusively, this invention relates to methods and apparatus for removing contaminants from surfaces.

The removal of contaminants from various surfaces usually involves the use of aggressive solvents or cleaners, or the use of mechanical methods such as sand blasting. Such methods can suffer from the disadvantage that physical or chemical damage may be caused to the substrate.

According to one aspect of this invention, there is provided an apparatus for treating a surface with a surface treatment medium, the apparatus comprising an absorbent member for holding the surface treatment medium, the absorbent member having a facing portion to contact the surface, and the apparatus further including a mounting member having a formation for mounting the absorbent member to the apparatus, wherein the mounting member has a sealing arrangement extending around the absorbent member to provide a seal to obviate or restrict leakage of the surface treatment medium from the apparatus. The mounting member may be chemically resistant to the surface treatment medium.

According to another aspect of this invention, there is provided an apparatus for treating with a surface treatment medium a surface of an article, the apparatus comprising an absorbent member for holding the surface treatment medium, the absorbent member having a facing portion to contact the surface of the article, and the apparatus further including a mounting member having a formation for mounting the absorbent member, wherein the formation is arranged to correspond with the shape of at least a region of the article, wherein the article can be mounted on the formation to provide intimate contact between the facing portion and said region of the article.

According to another aspect of this invention, there is provided an apparatus for treating a surface with a surface treatment medium, the apparatus comprising an absorbent member for holding the surface treatment medium, the absorbent member having a facing portion to contact the surface, the apparatus further including a mounting member having a formation for mounting the absorbent member, and a temperature control means in association with the mounting member to control the temperature of the surface treatment medium.

According to another aspect of this invention, there is provided an apparatus for treating a surface with a surface treatment medium, the apparatus comprising an absorbent member for holding the surface treatment medium, a mounting member for mounting the absorbent member, and a pressure control means, wherein the absorbent member has a facing portion to contact the surface, and the pressure control means applies a substantially uniform pressure across the absorbent member to effect intimate contact between the facing portion and the surface. The pressure control means may effect a seal around the absorbent member.

According to another aspect of this invention, there is provided an apparatus for treating a surface with a surface treatment medium, the apparatus comprising an absorbent member for holding the surface treatment medium, the absorbent member having a facing portion to contact the surface, and the apparatus further including a mounting member having a formation for mounting the absorbent member, the mounting member having an edge extending around the absorbent member to provide a seal to obviate or restrict leakage of the surface treatment medium from the apparatus, wherein the surface treatment medium can be selected from one or more of the following group of surface treatment media: aqueous/nonaqueous surfactant based solutions; aqueous solutions of inorganic/organic compounds; nonaqueous solutions of inorganic/organic compounds; polar aprotic solvents; hydrocarbon solvents; mono-basic esters; di-

basic esters; tri-basic esters; glycols; glycol ethers; cyclic carbonates; ketones; alcohols; ionic liquids liquid organic or inorganic compounds ; enzymatic solutions.

According to another aspect of this invention, there is provided a method of treating a surface of an article, comprising applying a surface treatment medium to an absorbent member having a facing portion to contact the surface, arranging the absorbent member on a formation on a mounting member, effecting contact between the surface treatment medium and the surface for a sufficient period of time to effect the treating of the surface, wherein the mounting member has a sealing arrangement extending around the absorbent member to provide a seal to obviate or restrict leakage of the surface treatment medium from the apparatus. The mounting member may be chemically resistant to the surface treatment medium.

According to another aspect of this invention, there is provided a method of treating with a surface treatment medium a surface of an article, comprising applying a surface treatment medium to an absorbent member having a facing portion to contact the surface, arranging the absorbent member on a formation on a mounting member, effecting contact between the surface treatment medium and the surface for a sufficient period of time to effect the treating of the surface, wherein the formation is arranged to correspond with the shape of at least a region of the article, whereby the formation can contact said region of the article to provide intimate contact between the facing portion and said region of the article.

According to another aspect of this invention, there is provided a method of treating a surface, comprising applying a surface treatment medium to an absorbent member having a facing portion to contact the surface, arranging the absorbent member on a formation of a mounting member, effecting contact between the surface treatment medium and the surface for a sufficient period of time to effect the treating of the surface, and controlling the temperature of the surface treatment medium during said treatment.

According to another aspect of this invention, there is provided a method of treating a surface, comprising applying a surface treatment medium to an absorbent member having a facing portion to contact the surface, arranging the absorbent member on a formation of a mounting member, effecting contact between the surface treatment medium and the surface for a sufficient period of time to effect the treating of the surface, and applying a substantially uniform pressure across the surface, during said treatment.

According to another aspect of this invention, there is provided a method of treating a surface, comprising applying a surface treatment medium to an absorbent member having a facing portion to contact the surface, arranging the absorbent member in a formation of a mounting member, effecting contact between the surface treatment medium and the surface for a sufficient period of time to effect the treating of the surface, wherein the surface treatment medium can be selected from one or more of the following group of surface treatment media: aqueous/nonaqueous surfactant based solutions; aqueous solutions of inorganic/organic compounds; nonaqueous solutions of inorganic/organic compounds; polar aprotic solvents; hydrocarbon solvents; mono-basic esters; di-basic esters; tri-basic esters; glycols; glycol ethers; cyclic carbonates; ketones; alcohols; ionic liquids, liquid organic or inorganic compounds ; enzymatic solutions.

The mounting member may comprise a receiving member for receiving the absorbent member. The formation may be a recess defined by the receiving member.

The recess may correspond with the shape of at least a region of the article. The recess can receive said region of the article to provide said intimate contact between the facing portion and said region of the article. The recess may surround, or partially surround, a non-planar region of the article, to provide the aforesaid intimate contact therewith.

In one embodiment, the formation may be an outer surface of the mounting member. The absorbent member may be provided on said outer surface. In another embodiment the mounting member may constitute an insertion member for insertion into the article to treat an inner surface of the article.

At least a part of the mounting member may be inflatable to apply a pressure to press the absorbent member on the article. The mounting member may include a resistant member, which may be inflatable to apply the aforesaid pressure.

The absorbent member may comprise a pad, and may be formed of an absorbent material. The absorbent material may be capable of absorbing and retaining the surface treatment medium in intimate contact with the surface. The absorbent member may be flexible.

Suitable absorbent materials may comprise a foamed, natural or artificial polymer such as rubber or polyurethane; a woven or non-woven textile comprising natural or synthetic fibres such as wool, polyester, cellulose, glass, carbon or ceramic; an organic, inorganic or mineral-based powder such as starch, zeolite or talc or a hollow fibre material.The hollow fibre materials may comprise cellulosic fibre pads.

The mounting member may have a sealing arrangement extending around the absorbent member to provide a seal to obviate or restrict leakage of the surface treatment medium from the apparatus. The mounting member may be chemically resistant to the surface treatment medium.

The sealing arrangement may comprise an edge arrangement, which may comprise a main edge member and a seal member extending from the edge member, the seal member being configured to provide aforesaid seal. The seal member may

comprise a suitable sealing material, such as a fluoroelastomer, thermoplastic elastomer, silicone rubber, nitrile rubber.

The surface may be the surface of an article. The seal member may be configured to engage either the article to be treated, or a further component of the apparatus.

The apparatus may include a base member upon which the mounting member may be mounted. The seal arrangement may form a seal by engaging the base member. The base member may be arrangeable above and/or below the mounting member.

The recess may surround, or partially surround, the non-planar region of the article, to provide the aforesaid intimate contact therewith.

The apparatus may comprise first and second opposed mounting members, each defining a respective recess. The apparatus may include first and second absorbent members, each being received on the formation of the respective first and second mounting members. The first and second mounting members may be arrangeable in face to face contact with each other. Each formation may be configured to mount thereon a region of the article when the first and second mounting members are in said face to face contact.

The apparatus may include securing means to hold the first and second mounting members in said face to face contact.

The first and second opposed mounting members may surround the article when the first and second mounting members are secured to one another. The pressure control means may be operated to increase or decrease the pressure between the first and second mounting members.

The first and second mounting members may provide a casing to encase the article when the first and second mounting members are in face to face contact. The pressure control means may comprise a pump to pump air into or out of the casing to increase or decrease the pressure therein.

The absorbent member may be chemically resistant to the surface treatment medium, and may be thermally stable. The absorbent member may be configured to correspond with the shape of the region of the article to be treated. In one embodiment, the absorbent member may be generally planar. In another embodiment, the absorbent member may be curved. In another embodiment, the absorbent member may define a recess to correspond to the shape of the region of the article to be treated.

The absorbent member may have a facing portion to engage the surface of the article to be treated. In one embodiment, the facing portion may constitute part of the absorbent member. In this embodiment, the absorbent member may be formed of a material having a smoothness of 4 to 5 on the American Association of Textile Colorists and Chemists. (AATCC) scale, preferably, substantially 5 on the AATCC scale.

In another embodiment, the facing portion may comprise a facing layer on the absorbent member. The facing layer may be formed of a material having a surface smoothness of 4 to 5 on the AATCC scale, preferably, substantially, 5 on the AATCC scale.

The apparatus may further include a resistant element on the absorbent member. The resistant element may be provided between the absorbent member and the mounting member.

The resistant element may be provided to prevent leakage of the surface treatment medium from the absorbent member. The resistant element may retain the integrity of the absorbent member.

In one embodiment, the resistant element may have an edge portion to extend around the absorbent member. The edge portion of the resistant element may contribute to the sealing of the mounting member.

The resistant element may be formed of a material that is chemically resistant to the surface treatment medium, and may be inert to the surface treatment medium. The resistant element is desirably not adhesively bonded to the absorbent member.

The resistant element may be thermally stable, particularly at the temperatures used during the treatment of the article.

In one embodiment, the resistant element may comprise a film provided on the absorbent member. The film may be chemically inert. The film may be thermally stable, particularly at the temperatures used during the treatment of the article. The film may be formed of a metallic foil, or a polymeric material, such as a polyimide. Suitable films are sold under the trade mark KAPTON.

The mounting member may be chemically resistant to the surface treatment medium. It is desired that the mounting member is substantially chemically inert to the surface treatment medium.

The mounting member may constitute an insulating member, and may insulate the absorbent member thermally. The mounting member may insulate the absorbent member chemically. The mounting member may chemically protect the heating element.

The feature of the mounting member being thermally insulating provides an advantage in the embodiments described herein that it allows the surface treatment processes to be carried out above and below room temperature.

The mounting member is desirably thermally stable, particularly at the temperatures used during the treatment of the article.

The mounting member may include a main portion extending over the absorbent member. The edge arrangement may extend from the main portion. In one embodiment, the edge arrangement may depend from the main portion.

The apparatus may include a pressure control means to apply pressure to the absorbent member. The pressure control means may be arranged to apply a substantially uniform pressure across the absorbent member.

The pressure control means may comprise a weight on or in the mounting member. Alternatively, the pressure control means may comprise opposed pressure members which may be secured to one another in a pressure applying relationship by securing members.

The apparatus may include a temperature control means to control the temperature of the surface treatment medium. The temperature control means may be associated with the mounting member, and may comprise heating and/or cooling elements, which may be arranged within the mounting member.

The temperature control means may further include a conduit arrangement to provide a heated or cooled fluid to the heating and/or cooling elements.

Alternatively, the heating and/or cooling elements may be electrically operated to heat or cool the mounting member. An electrical controller may be provided to control the heating and/or cooling elements.

The surface treatment medium can be selected from one or more of the following group of surface treatment media: aqueous/non aqueous surfactant based solutions; aqueous solutions of inorganic/organic compounds; non-aqueous solutions of inorganic/organic compounds; polar aprotic solvents; hydrocarbon solvents; monobasic esters; di-basic esters; tri-basic esters; glycols; glycol ethers; cyclic carbonates; ketones; alcohols; ionic liquids; liquid organic or inorganic compounds; enzymatic solutions.

The step of applying the surface treatment medium to the absorbent member may comprise impregnating the absorbent member with the surface treatment medium.

The step of applying the absorbent member to the article may comprise applying a force to the absorbent member sufficient to effect intimate contact between the absorbent member and the substrate.

The step of contacting the surface treatment medium with the surface of the article may comprise effecting the aforesaid contact for a period of time of substantially 5 minutes to substantially 24 hours. The aforesaid contact between the surface treatment medium and the surface of the article is desirably effected for a period of time of substantially 15 minutes to substantially 8 hours. The aforesaid contact between the surface treatment medium and the surface of the article is more desirably effected for a period of time of substantially 20 minutes to substantially 2 hours.

In one embodiment, the method may comprise maintaining the absorbent member in a substantially static condition relative to the surface during the treatment of the surface.

The aforesaid treatment temperature may be between the melting and boiling points of the surface treatment medium. The aforesaid treatment temperature may be within a range of -60 ⁰ C to 300 ⁰ C. The treatment temperature is desirably within a range of -20 ⁰ C to 250 ⁰ C. The treatment temperature is more desirably within a range of 0°C to 200°C.

The step of arranging the absorbent member on or around the article may comprise heating the absorbent member for the aforesaid period of time.

In a first embodiment, the aforesaid treatment temperature may be within the range of 10°C to 90°C. The treatment temperature is desirably within the range of 25°C to 80 ⁰ C. The treatment temperature may be within the range of 35°C to 75°C.

The treatment temperature ranges specified for the first embodiment may be suitable for use with surface treatment media comprising aqueous surfactant based solutions and/or aqueous solutions of inorganic and/or organic compounds.

In a second embodiment, the aforesaid treatment temperature may be within a range of 20 ⁰ C to 180°C. The treatment temperature is desirably within a range of 70°C to 120°C. The treatment temperature may be within a range of 85°C to 105 ⁰ C.

The treatment temperature ranges specified for the second embodiment may be suitable for use with surface treatment media comprising polar aprotic solvents.

In a third embodiment, the aforesaid treatment temperature may be within a range of O ⁰ C to 160 ⁰ C. The treatment temperature is desirably within a range of 50 ⁰ C to 110 ⁰ C. The treatment temperature may be within a range of 65°C to 85°C.

The treatment temperature ranges specified for the third embodiment may be suitable for use with surface treatment media comprising hydrocarbon solvents.

In a fourth embodiment, the aforesaid treatment temperature may be within a range of -50 ⁰ C to 170 ⁰ C. The treatment temperature is desirably within a range of 0 ⁰ C to 170 ⁰ C. The treatment temperature may be within a range of 70 ⁰ C to 12O ⁰ C.

The treatment temperature ranges specified for the fourth embodiment may be suitable for use with surface treatment media comprising mono-basic, di-basic, and/or tribasic esters.

In a fifth embodiment, the aforesaid treatment temperature may be within a range of -60 ⁰ C to 220 ⁰ C. The treatment temperature is desirably within a range of -20°C to 18O ⁰ C. The treatment temperature may be within a range of O ⁰ C to 90 ⁰ C.

The treatment temperature ranges specified for the fifth embodiment may be suitable for use with glycols and/or glycol ethers.

In a sixth embodiment, the aforesaid treatment temperature may be within a range of -50°C to 220°C. The treatment temperature may be within a range of -1O ⁰ C to 180 ⁰ C. The treatment temperature may be within a range of 1O ⁰ C to 90 ⁰ C.

The temperature ranges specified for the sixth embodiment may be suitable for use with cyclic carbonates.

In a seventh embodiment, the aforesaid treatment temperature may be within a range of -40 ⁰ C to 170 ⁰ C. The treatment temperature is desirably within a range of O ⁰ C to 120 ⁰ C. The treatment temperature may be within a range of 30 ⁰ C to 60°C.

The temperature ranges specified for the seventh embodiment may be suitable for use with ketones and/or alcohols.

In an eighth embodiment, the aforesaid treatment temperature may be within a range of -50 ⁰ C to 300 ⁰ C. The treatment temperature is desirably within a range of 2O ⁰ C to 250°C. The treatment temperature may be within a range of 50°C to 200°C.

The temperature ranges specified for the eighth embodiment may be suitable for use with ionic liquids.

In an ninth embodiment, the aforesaid treatment temperature may be within a range of 25°C to 70 ⁰ C. The treatment temperature is desirably within a range of 35°C to 65°C. The treatment temperature may be within a range of 45°C to 60°C.

The temperature ranges specified for the ninth embodiment may be suitable for use with enzymatic solutions.

The step of heating the absorbent member may comprise the use of an electric heater, hot water or steam, or any other suitable heating arrangement.

The absorbent member may have a surface treatment medium thereon. The absorbent member may be impregnated with the surface treatment medium.

The article may comprise a substrate having a substance thereon. The method and apparatus may comprise a method and apparatus for removing the substance from

the substrate. The method and apparatus may comprise a method and apparatus for cleaning a surface.

In one embodiment, the absorbent member may comprise a pad comprising a first flexible pad element formed of an absorbent material. The absorbent material is desirably capable of absorbing and retaining the surface treatment medium in intimate contact with the substrate.

The first flexible pad element may be chemically resistant to the surface treatment medium and, where appropriate, thermally resistant to the temperature used. The first flexible pad element may be a generally planar element.

In this embodiment, the absorbent element may further include a second flexible pad element, which may be chemically resistant to the surface treatment medium and, where appropriate, thermally resistant to the temperature used. In the embodiments where the second flexible pad element is used, the second embodiment provides the advantage that it protects the heater and/or the operator from the surface treatment medium.

The second flexible element may comprise a backing material. The second flexible pad element may be a generally planar element. The backing material may be provided to give protection for the heating element against the surface treatment medium during use. The backing material may include an insulating component.

The second flexible element may comprise a chemically and/or thermally stable film that may prevent leakage. This feature provides an advantage in one embodiment of providing chemical resistance and/or protection. Alternatively, the second flexible element may comprise an element having integral thermal insulation and chemical and/or thermal stability.

In one embodiment, the absorbent element may further include a third pad element, which may be a retaining element. The retaining element may be provided to retain the integrity of the first flexible element during use, for example when the absorbent element is placed on and/or removed from the substrate. The retaining element may be a generally planar element

The first flexible pad element may be formed from one or more of the following: a foamed, natural or artificial polymer such as rubber or polyurethane; a woven or non- woven textile comprising natural or synthetic fibres such as wool, polyester, cellulose, glass, carbon or ceramic; an organic, inorganic or mineral-based powder such as starch, zeolite or talc or a hollow fibre material. The hollow fibre materials may comprise cellulosic fibre pads.

The second flexible pad element may be formed of one or more of the following: a glass fibre or mineral wool, a cellulose padding material, or a high-temperature polymeric material, such as a polyimide film; a metallic foil or sheet, such as aluminium or steel, The polymer film may comprise a fluorinated polymer, nylon, a polyolefin, a block copolymer, or an elastomer.

The retaining element may be formed of a holding material capable of holding a powder, such as a non woven textile, microporous polymer sheeting, metallic, polymeric or woven gauze. The holding material may provide a scaffold to retain the powder material. The holding material may provide a substantially smooth surface.

The absorbent member may include an insulating element, which may comprise a glass fibre or mineral wool, a cellulose padding material, or a high-temperature polymeric material, such as a polyimide film.

The substance may comprise a contaminant. The substance may be chemically bonded to the substrate. The surface treatment medium may comprise a cleaning

agent, which may be for removing a contaminant from the surface of the substrate. The cleaning agent may comprise a cleaning material. The surface treatment medium may comprise a cleaning formulation.

The substrate may have a surface having a layer of an oxide thereon.

The substrate may comprise a metallic substrate, which may be a ferrous based substrate, a light alloy such as an aluminium, a magnesium or a titanium alloy. Alternatively, the substrate may comprise a polymeric substrate, which may comprise a polyolefin, such as polyethylene or polypropylene, or other polymer. Alternatively, the substrate may comprise a ceramic material.

The surface treatment medium may comprise a liquid, which may comprise a solvent, such as an aqueous or non-aqueous solvent. The non-aqueous solvent may be an organic solvent. Alternatively, the liquid may comprise a soap solution or a liquid organic or inorganic compound. The surface treatment medium may be any suitable liquid capable of removing the substance from the substrate.

The surface treatment medium may comprise one or more selected from: aqueous/nonaqueous, surfactant based solutions; aqueous/nonaqeous solutions of inorganic/organic compounds; polar aprotic solvents; hydrocarbon solvents; monobasic, di-basic and/or tri-basic esters; glycols and/or glycol ethers; cyclic carbonates; ketones and/or alcohols; ionic liquids; liquid organic or inorganic compounds; enzymatic solutions.

The aqueous/nonaqueous, surfactant based solutions may be for example cationic, anionic, non-ionic, amphoteric surfactant based solutions, but it will be appreciated by the skilled person that other aqueous/nonaqueous, surfactant based solutions may be used.

The aqueous/nonaqueous solutions of inorganic/organic compounds may be, for example hydrogen peroxide, sodium carbonate, sodium hypochlorite but it will be appreciated by the skilled person that other aqueous/nonaqueous solutions of inorganic/organic compounds may be used.

The polar aprotic solvents may be, for example dimethyl sulphoxide, n-methyl pyrrolidone but it will be appreciated by the skilled person that other polar aprotic solvents may be used.

The hydrocarbon solvents may be, for example d-limonene, pinene but it will be appreciated by the skilled person that other hydrocarbon solvents may be used.

The mono-basic, di-basic and/or tri-basic esters may be, for example ethyl lactate, butyl acetate, dimethyl succinate, triethyl citrate but it will be appreciated by the skilled person that other mono-basic, di-basic and/or tri-basic esters may be used.

The glycols and/or glycol ethers may be, for example diethylene glycol, monobutyl ether but it will be appreciated by the skilled person that other glycols and/or glycol ethers may be used.

The cyclic carbonates may be, for example propylene carbonate but it will be appreciated by the skilled person that other cyclic carbonates may be used.

The ketones and/or alcohols may be, for example butyl carbitol, γ-butyrolactone but it will be appreciated by the skilled person that other ketones and/or alcohols may be used.

The ionic liquid may be, for example 1 -ethyl, 3-methyl, imidazolium, tetrachloro- aluminium [EMI][TCA] but it will be appreciated by the skilled person that other ionic liquids may be used.

The enzymatic solutions may be, for example, solutions of protease, lipase, cellulase but it will be appreciated by the skilled person that other enzymatic solutions may be used.

The apparatus may comprise an inert member arranged on the absorbent member. It will be understood that in the embodiments described herein, the inert member comprises a material that is chemically resistant to the surface treatment medium.

The inert member may comprise a thermally insulating material. This feature provides the advantage in some embodiments of the invention that it prevents or mitigates heat transfer into or out of the apparatus.

The apparatus may comprise a force applying member for applying a force to the absorbent member to maintain intimate contact of the absorbent member and the surface treatment medium with the substance.

The apparatus may comprise a plurality of layers. The apparatus may comprise a first layer comprising the absorbent member, and a second layer comprising the heating arrangement. The first and second layers may be in contact with each other.

The apparatus may further comprise a third layer, which may comprise the inert member. The third layer may be arranged on the second layer.

The apparatus may comprise a fourth layer, which may comprise the force applying member.

The apparatus is generally flat for application to a planar surface. In a variation of this configuration, the apparatus may be curved for application to a curved surface.

In the first embodiment, the force applying member may comprise a weight for applying the force to the absorbent member.

Alternatively, the inert member may be arranged between the absorbent member and the heating arrangement. The inert member may be sufficiently thermally conductive to allow heat to be conducted to the absorbent member.

The force applying member may comprise a weight for applying the force to the absorbent member.

In a further variation, the apparatus may comprise a container for holding the article. The absorbent member may be provided in first and second parts engageable with one another to surround the article.

The absorbent member may define a recess, or a pair of opposed recesses in which the article can be received. The opposed recesses are preferably aligned with one another and may effect intimate contact between the article and the absorbent member.

The force applying member may comprise a casing to hold the absorbent member. The casing may be secured in a closed position to apply the force to the absorbent member.

In a further variation, the apparatus may comprise a rotary arrangement, which may comprise a treatment roller. The absorbent member may be mounted on the outer surface of the treatment roller. The treatment roller may be heated.

The apparatus may comprise a transport member for transporting the article to the rotary arrangement. The transport member may transport the article through the rotary arrangement during said application of heat and the force.

The transport member may comprise a belt on which the article is mounted. The belt may be an endless belt.

The rotary arrangement may comprise an axle upon which the treatment roller is mounted. A subsidiary roller may be arranged generally opposite the treatment roller for assisting movement of the article across the treatment roller and in applying a force to the article to press the article against the treatment roller.

In a further variation, the apparatus may comprise an insertion arrangement for insertion into an article having a hollow region requiring treatment of an internal surface. The absorbent member may be arranged on the outside of the insertion arrangement.

The heating arrangement may be surrounded by the absorbent member. The inert member may be provided between the heating arrangement and the absorbent member.

The inert member may be inflatable to apply the force to the absorbent member to press the absorbent member against the article. The inert member may be inflatable by a gas, such as compressed air, or by an hydraulic fluid.

After the above treatment steps, the method may comprise subjecting the article to a rinsing or washing stage to remove the contaminant therefrom.

Embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a sectional side view of a first embodiment of a surface treatment apparatus;

Figure 2 is a sectional side view of a variation of the first embodiment;

Figure 3 is a sectional side view of a second embodiment of a surface treatment apparatus;

Figure 4 is a perspective view of a third embodiment of a surface treatment apparatus;

Figure 5 is a sectional side view of a fourth embodiment of a surface treatment apparatus;

Figure 6 shows a fifth embodiment of a surface treatment apparatus;

Figure 7 is a sectional side view of the fifth embodiment;

Figure 8 is a sectional side view of an absorbent member;

Figure 9 is a sectional side view of a sixth embodiment of a surface treatment apparatus;

Figure 10 is a graph showing comparative results in the cleaning of a surface in accordance with an embodiment of the invention;

Figure 11 is a graph showing comparative results in the cleaning of a surface in accordance with another embodiment of the invention; and

Figure 12 shows the results of an XPS Survey of a contaminated aluminium sheet before and after cleaning.

Referring to Figure 1 , there is shown a diagrammatic sectional side view of a first embodiment of an apparatus 10 for treating an article 12. The article 12 comprises a substrate 14 and a contaminant 16 on the surface 18 of the substrate 14.

In some circumstances, for example where the substrate 14 is in the form of a metal, an oxide may form on the surface of the metal. While not wishing to be limited to any particular theory, it is believed that the contaminants form chemical bonds with the oxide on the surface 18.

The apparatus 10 comprises an absorbent member in the form of a pad 20 comprising an absorbent material, which can be impregnated with a suitable surface treatment medium, in the form of a solvent or cleaning agent. If desired, the pad can be supplied impregnated with the surface treatment medium. The pad 20 is described in more detail below.

The apparatus 10 includes a mounting member, in the form of a receiving member 23 defining a recess 25. The pad 20 is held within the recess 25. The mounting member 23 includes a sealing arrangement 27 which defines the recess 25.

The receiving member 23 includes a main part 23A extending over the pad 20. The sealing arrangement 27 is in the form of downwardly depending wall members extending from the main part 23A to seal against the article 12, or in some cases against a further component of the apparatus 10.

In the embodiments described herein, the surface treatment medium comprises a cleaning agent for removing a contaminant from the surface of the substrate 14. The cleaning agent can be selected from the cleaning agents listed in Table 1 below.

It will be appreciated by the skilled person that the list of cleaning agents in Table 1 is not an exhaustive list, and other cleaning agents can be used.

The substrate may be selected from substrates listed in Table 1 below. It will be appreciated by the skilled person that the list of substrates in Table 1 is not an exhaustive list, and other substrates can be used.

The pad 20 has a facing portion 22 which is arranged in intimate contact with the surface 18 of the substrate 14, and thereby also in intimate contact with the contaminant 16 on the surface 18.

A heating arrangement 24 is provided in the receiving member 23. The heating arrangement extends over the pad 20 to provide heat to the pad 20, thereby heating the surface treatment medium and the contaminant 16.

The heating arrangement 24 can be any suitable heating arrangement, for example and electric heater or assembly to receive hot water or steam. The heating source or power supply 26 provides the electric power, or supplies the heating medium, to the heating arrangement 24.

An example of the pad 20 is shown in Figure 8, and comprises a first flexible pad element 21A, which is generally planar in configuration. The first flexible element is formed of an absorbent material to absorb the surface treatment medium.

The first flexible pad element 21 A may be formed from one or more of the following: a foamed, natural or artificial polymer such as rubber or polyurethane; a woven or non-woven textile comprising natural or synthetic fibres such as wool, polyester, cellulose, glass, carbon or ceramic; an organic, inorganic or mineral-based powder such as starch, zeolite or talc or a hollow fibre material.. The hollow fibre materials may comprise cellulosic fibre pads.

It will be appreciated by the skilled person that the first flexible pad element 21A could be formed of other suitable absorbent materials.

The pad 20 further comprises a second flexible pad element 21 B, also generally planar in configurations and provided on one face of the first flexible pad element 21A. The first flexible pad element 21A is generally of the same size and shape as the second flexible pad element 21 B.

The second flexible pad element 21 B is formed of a material which is chemically and thermally resistant in the context of the cleaning regime used in any particular cleaning application, and protects the heating arrangement 24 from the cleaning agent.

The second flexible pad element 21 B constitutes a backing material for the first flexible pad element 21A.

The second flexible pad element 21 B may be formed from one or more of the following: a glass fibre or mineral wool, a cellulose padding material, or a high- temperature polymeric material, such as a polyimide film; a metallic foil or sheet, such as aluminium or steel, The polymer film may comprise a fluorinated polymer, nylon, a polyolefin, a block copolymer, or an elastomer.

It will be appreciated by the skilled person that the second flexible pad element 21 B could be formed of other suitable chemically and thermally resistant materials.

The pad 20 also includes a third pad element 21 C, in the form of a retaining element. The third pad element 21 C acts to retain the integrity of the absorbent material during the use of the pad 20, particularly when the pad 20 is being placed on or removed from the article 12 to be cleaned. The third pad element 21 C is

provided on the opposite face of the second pad element 21 B to the face to which the first pad element 21A is attached.

If desired, in some embodiments, the heating arrangement 24 can be incorporated as an integral part of the pad 20. An example of this is shown in Figure 8, in which the heating arrangement 24 is represented schematically as heating elements 24A within the third pad element 21 C. Alternatively, the heating elements 24A could be provided on the second flexible pad element 21 B.

Where the heating arrangement 24 is provided as an integral part of the pad 20, an inert element 21 D can be provided on the third pad element 21 C, on the opposite face of the third pad element 21 C to the face to which the second pad element 21 B is attached. The inert element 21 D is particularly useful if the pad 20 is arranged as a pocket or pouch, and the heating elements 24A are provided on the second flexible pad element 21 B.

Referring to Figures 1 to 7, where the heating arrangement 24 is provided separately to the pad 20, a resistant element, in the form of an inert member 28, is arranged over the heating arrangement 24 to prevent leakage of the surface treatment medium from the apparatus 10. The inert member 28 is formed of a material that is chemically resistant to the surface treatment medium and which is thermally insulating.

The receiving member 23 constitutes the heating arrangement 24 and the inert member 28.

A force applying member in the form of a weight 30 is provided at an upper region of the apparatus 10 to apply a force to the pad 20 to maintain the intimate contact between the pad 20 and the contaminant 16. The weight 30 may be an integral part of the apparatus 10, or it may be an external weight.

In use, the apparatus 10 is arranged on the article 12, such without the pad 20 contact the contaminant 16 on the surface 18. The weight 30 presses down on to the pad 20 and effects intimate contact between the pad 20 and the surface 18, thereby effecting intimate contact between the pad 20 and the contaminant 16.

The heating arrangement 24 is then switched on to apply heat to the apparatus 10 to heat the pad 20. The heating arrangement 24 applies the heat for a predetermined period of time, in the range of 20 minutes to two hours, although the period of time could be as low as five minutes or as long as 24 hours.

The heat may be applied to raise the temperature of the pad 20 to a desired treatment temperature. The temperature to which the pad 20 is raised is dependent upon the contaminant, the cleaning agent, and the substrate 14, as shown in Table 1 below.

Table 1 shows a range of cleaning agents, the temperature ranges at which they can be employed, the substrates on which they can be used, and the contaminants the respective cleaning agents can remove.

After the predetermined period of time for heating the apparatus 10 has elapsed, the apparatus 10 is lifted from the article. The contaminant is then wiped off the surface 18 or is removed in a post-treatment rinsing or washing stage.

It will be understood by those skilled in the art that the apparatus shown in Figure 1 can be modified to treat both sides of a planar article, if desired

Whilst not wishing to be limited to any particular theory, it is believed that the surface treatment medium absorbed on the pad 20, together with the application of heat and / or pressure for the predetermined time, breaks the chemical bonds between the contaminant 16 and the outer surface of the substrate 18.

Referring to Figure 2, there is shown a variation of the first embodiment, which is suitable for use where the surface 18 is curved. In Figure 2, the features have been given the same reference numeral as in Figure 1. The apparatus 10 shown in Figure 2 is curved to the same extent as the article 12.

The apparatus 10 shown in Figure 2 is used in a similar way to the apparatus 10 shown in Figure 1 , and described above.

Referring to Figure 3, there is shown a second embodiment of the invention, which is similar to the embodiment shown in Figure 1, but the heating arrangement 24 is provided over the inert member 28. In this embodiment, the inert member 28 is thermally conductive to allow heat to be conducted to the pad 20.

The apparatus 10 shown in Figure 3 is used in a similar way to the apparatus shown in Figure 1 , as would be understood by those skilled in the art.

Figure 4 shows a third embodiment, suitable for treating articles where the external surface is not planar or is complex. In the third embodiment, the pad 20 is held within a chemically inert casing 128.

The casing 128 is in the form of first and second receiving members in the form of first and second casing members 128A, 128B pivotally attached together at a hinge 130. The first and second casing members 128A and 128B can be pivotally moved from the open position shown in Figure 4 to a closed position about the hinge 130 and locked in the closed position by a lock 131.

The pad 20 is in the form of a first pad member 2OA mounted within the first casing member 128A, and a second pad member 2OA mounted within the second casing member 128A. The first pad member 2OA defines a first recess 132A, and the second pad member 2OB defines a second recess 132B. The pad members 2OA, 2OB provide respective facing portions 22A, 22B to engage the article 12.

The first and second pad members 2OA and 2OB receive the article 12 in their respective recesses 132A, 132B, when the first and second casing members 128A, 128B are in their closed position. The recesses 132A and 132B are arranged to correspond with the shape of the region of the article 12 to be received therein. The recesses 132A, 132B can receive the aforesaid regions of the article in a manner that provides intimate contact between the facing portions 22A, 22B and the respective regions of the article 12.

When the casing 128 is closed, the first and second casing members 128A and 128B apply a force to the first and second pad members 2OA and 2OB to provide the intimate contact between the article and the first and second pad members 2OA and 2OB.

The heating arrangement 24 is provided within the first casing member 128A between the first casing member 128A and the first pad member 2OA. The heating source 26 supplies electricity or heating fluid to the heating arrangement 24 to heat the pad 20 when the casing 128 is closed and locked.

A pressure control means 133 is provided to increase or decrease pressure within the casing 128, when the casing 128 is closed. The pressure control means 133 may comprise a pump to pump air into the casing 128, thereby increasing pressure therein, or to pump air out of the casing 128, thereby decreasing the pressure therein. The pressure control means 133 is connected to the casing 128 by piping 135. This feature provides the advantage in this embodiment of allowing the use of volatile treatment agents, such as hydrofluorocarbons, by preventing evaporation of the volatile treatment agent at the temperatures used.

The casing members 128A, 128B also act as the inert member, preventing leakage of the cleaning agent and transfer of heat to / from the environment .In use, the pad members 2OA, 2OB are first impregnated with the solvent or cleaning agent, if the pad members 2OA, 2OB have not been supplied so impregnated.

The article 12 is then arranged in the first and second recesses 132A, 132B. The first and second casing members 128A, 128B are closed, and then locked by means of the lock 131.

When the casing 128 is locked, with the casing members 128A, 128B in the closed condition, the casing members 128A, 128B press inwardly on the respective pad members 2OA, 2OB to effect the intimate contact of the pad 20 with the article 12, at a substantially uniform pressure.

The heating arrangement 24 is then switched on to heat the pad 20 to a temperature in the range in the range specified in Table 1 for the relevant cleaning agent.

After heating, the lock 131 is released, the casing 128 opened, and the article 12 is taken out. The contaminant can then be removed from the article 12 by washing, rinsing or wiping it off

Referring to Figure 5, there is shown a fourth embodiment in which the apparatus 10 comprises a rotary arrangement 210 in the form of a treatment roller 212 mounted on an axle 208. The axle 208 is mounted on a support 206.

The pad 20 is of a cylindrical configuration and is mounted around the outer surface of the treatment roller 212. The heating arrangement 24 is also cylindrical and is provided around the treatment roller 212 and is heated by the heating source or power supply 26. Alternatively, the treatment roller 212 can itself be heated by the heating source or power supply 26.

The rotary arrangement 210 also includes a subsidiary roller 214 mounted opposite and, in the embodiment shown, below the treatment roller 212.

The contaminated article 12 is elongate and is arranged on a pair of supports 215A, 215B which support the subsidiary roller 214 there between on an axle 216. The article extends from one of the supports 215A to the other of the supports 215B. In this position, the elongate article 12 is arranged between the treatment roller 212 and a subsidiary roller 214.

The article 12 is below the treatment roller 212 and is moved in the direction of the arrow A to be treated by the treatment roller 212.

The subsidiary roller 214 is arranged to provide an upward force to the article 12, as shown by the arrow B, to press the article 12 against the treatment roller 212. As a result, the treatment roller 212 applies a downward reaction force onto the article 12.

The subsidiary roller 214 can be driven to move the article 12 between the treatment roller 210 and the subsidiary roller 214.

It will be understood by those skilled in the art, that the apparatus shown in Figure 5 can be modified to include a post-treatment rinsing or wiping stage.

Referring to Figures 6 and 7, there is shown a fifth embodiment suitable for removing contaminant material on the inside of an article 18. In the fifth embodiment, the apparatus 10 comprises an insertion member 310 to be received within a recess, or hollow region, 312 in the article 12, as shown in Figure 6.

The apparatus 10 shown in figure 6 and 7 is shown with an optional inflator 314 to inflate the inert member 28 and apply the force to the pad 20 to maintain the intimate contact between the pad 20 and the surface 18.

Referring to figure 7, there is shown a sectional side view of the insertion member 310, which comprises the pad 20, which is of a cylindrical configuration extending around the outside of the insertion member 310. The pad 20 has a facing portion 22 to engage the inside surface of the article 12. The inert member 28 is provided internally of the pad 20 and, if desired, is provided with suitable inflation means to allow the inert member to be inflated and to press the pad 20 against the internal surface 18 of the article 12.

Where the inflator is present, the inert member 28 is connected to the inflator 314, which may be in the form of a compressed air pump, a gas generator or a hydraulic pump.

The heater 24 is arranged within the inert member 28 and is connected to the heating source or power supply 26 to provide heat via the inert member 28 to the pad 20. In this embodiment, the inert member 28 is thermally conductive.

The pad 20 is impregnated with the treatment medium in the form of a solvent or cleaning agent, unless the pad has been supplied impregnated with such substances.

The insertion member 310 is inserted into the article 12 and the inert member 28 may be inflated by the inflator 314 (if present) to press the pad of 20 against the internal surface of the article 12. This ensures intimate contact of the pad 20 with the internal surface of the article 12 and the contaminant 16 thereon.

When the intimate contact between the pad 20 and the internal surface of the article 12, has been achieved on inflation of the inert member 28, the heater 24 is switched on to provide heat for the desired period of time to a desired temperature. At the end of the desired period of time, the inert member 28 is deflated, and the insertion member 310 is removed from the article 12. The contaminant can then be washed away.

Figure 9 is a diagrammatic sectional side view of a further embodiment of a surface treatment apparatus, generally designated 410, for cleaning the surface of an article 412, providing a substrate to be cleaned.

The surface treatment apparatus 410 comprises an absorbent member 420 in the form of a pad of a non-woven material, such as cellulose or viscose. The absorbent member 420 has a facing portion thereon, in the form of a facing layer 422, which contacts the surface of the article 412 to clean it, as described below.

Alternatively, the absorbent member 420 may have a facing portion, which may be a part of the absorbent member 420.

The absorbent member 420 is provided to absorb a surface treatment medium which, in the embodiment shown, is in the form of a cleaning agent.

The facing layer 422, or the absorbent member 420 when the absorbent member provides its own facing portion, is formed of a material which has a smoothness of substantially 5 on the American Association of Textile Colorists and Chemists. (AATCC) scale,

A receiving member 424 is provided, which defines a recess 426, to receive the absorbent member 420. The receiving member 424 has an edge arrangement 428 and a main portion 430. The edge arrangement 428 extends from the main portion 430, and depends therefrom, to define the recess 426.

The edge arrangement 428 comprises a wall member 432 which is attached to, and depends downwardly from, the main portion 424. A sealing member 434 extends from the lower edge of the wall member 432. The sealing member 434 is provided to seal against a base member 436, upon which the receiving member is supported. Alternatively, if the article 412 too large to be received in the recess 426, the sealing member 434 can engage the surface of the article 412 itself. The purpose of the sealing member is to prevent leakage of the surface treatment medium.

A resistant layer 438 is provided over the absorbent member 420, and is arranged in the recess 426 between the absorbent member 420 and the receiving member 424. The resistant layer is in the form of a film, for example of a polyimide, such as sold under the trade mark KAPTON.

The resistant layer 438 comprises a cover portion 439 to cover the absorbent member 420, and an edge portion 441 depending from the cover portion 439, and extending around the absorbent member 420. The edge portion 441 contributes to the sealing by the receiving member.

The resistant layer 438 is chemically inert to the surface treatment medium, and thereby provides a barrier to prevent the surface treatment medium contacting the receiving member 424, which may cause damage to any heating or cooling elements in the receiving member 424. The heating and cooling elements are described below.

The resistant layer 438 is also thermally stable at temperatures at which the cleaning takes place.

Temperature control means in the form of heating and/or cooling elements 440 are provided in the receiving member 424, which are connected to a heater/cooler 442. The heater/cooler 442 may provide a heated or cooled fluid via a conduit arrangement 444 to the heating/cooling elements 440.

Alternatively, the heating /cooling elements 440 may be electrically operated to heat or cool the receiving member, in which case, the feature designated by the numeral 442 represents an electrical controller, and the numeral 444 designates an appropriate cabling arrangement for the electrical power.

The receiving member 424 is formed of a material that is thermally stable at the cleaning temperatures used. The receiving member is also chemically inert to the various surface treatment media that can be used.

In the embodiment described, the receiving member 424 is thermally and chemically insulating, thereby allowing the surface treatment apparatus 410 to operate at

temperatures that are greater or less than room temperature without any, or any significant, heat transfer with the surroundings.

The receiving member 424 may include a pressure control means to apply a substantially uniform pressure across the absorbent member. The pressure control means may comprise a weight 446 within the receiving member 424. the weight 446 is shown in broken lines in Figure 9.

Alternatively, the pressure control means may comprise securing means to secure the receiving member to the base member 436, in a similar way to the lock 131 shown in Figure 4.

Examples

Examples of the use of embodiments of the invention will now be described:

Example A:

Removal of Surface Hydrocarbon Contamination from Aluminium Sheet

Cleaning Agent:

De-ionised water 58%

Diethylene glycol monobutyl ether 38% Sodium Carbonate 4%

Pad Material: Cellulose non-woven, backed by PETG / ACLAR polymeric film, no retaining film.

Flat device configuration, with ~ 2kg weighted cover

The surface was heated to 70 ⁰ C for 30 minutes, removed from system and washed with deionised water followed by air drying at room temperature.

Results:

Quadrupole SIMS analysis of the cleaned surface, in comparison with the uncleaned surface and two proprietary cleaning methods used in the aerospace industry showed that this treatment i.e. according to the embodiment in Example A, gave the best removal of hydrocarbon ion species, referenced to substrate aluminium ion intensity, in each case. The results are represented below in Table A, and shown in Graph A in Figure 10.

Table A

Example B:

Bactericidal Action in Milk Residues lnnoculated with Staphylococcus Aureus

Superbrush finish stainless steel sheet was inoculated with 100μl of staphylococcus

Aureus suspension (10 ⁸ cells) in milk, and allowed to dry.

The material was subjected to a number of soil / clean cycles (1 / 3 / 6) using: a) Water b) 5% household detergent formulation

c) Surface Treatment Technology according to an embodiment of the invention, namely:

Cleaning Agent:

Tartaric Acid 1.25%

Surfactant 2.5%

Deionised water 96%

Pad Material: Cellulose non-woven, backed by PETG / fluoropolymer film, no retaining film.

Flat device configuration, with ~ 2kg weighted cover

Heated to 75°C for 30 minutes, removed from system, rinsed with deionised water and rubbed using a crockmeter followed by air drying at room temperature.

Results:

Residual Total Viable Cell Count was measured by swabbing the surface and incubating on TVA plates for 24 hours, followed by counting of viable colonies. Viable count of samples wiped without detergent gradually increased with the number of soil/clean cycles, reaching a maximum of 1.3 x 10 ⁴ cells / cm ² removed by swabbing. Samples cleaned using household detergent had a higher TVC count after one cycle, and lower TVC counts after the third and sixth cycle in comparison with water. The surface treatment method according to an embodiment of the invention had no viable microbial cells detected after all examined cleaning cycles. The results are represented below in Table B, and shown in Graph B in Figure 11.

Table B

Example C:

Removal of Expanded Polyurethane Foam from Aluminium Sheet

Cleaning Agent:

Polar aprotic solvent 100%

Pad Material: Woven cellulosic fibre, backed by aluminium foil, no retaining film.

Flat device configuration, with ~ 2kg weighted cover

Heated to 70 ⁰ C for 20 minutes, removed from system, rinsed with deionised water

Prior to treatment the foam contamination was not easily removable except by scraping, causing scratch damage to the surface of the aluminium sheet. After treatment contamination could be easily wiped from the surface using a damp cloth.

Example D

XPS Analysis of Cleaning Polvurethane from Aluminium Sheet

Aluminium sheet coated with a layer of expandable polyurethane foam was analysed by X-ray photoelectron spectroscopy (XPS or ESCA), before and after cleaning by the cleaning process.

XPS is a surface analysis technique that measures the topmost 10 nanometers (10x10 ^"9 meters) of the sample surface. All elements excluding hydrogen and helium can be measured quantitatively by XPS.

The XPS survey spectra from the aluminium surface, before and after cleaning, are presented in Figure 12.

The element compositions of the top 10 nanometer depth of the exposed surfaces are calculated from the peak intensities in Figure 12 and are listed in Table D.

Surface Element Concentrations: Before and After Cleaning Aluminium Table D

The surface composition before cleaning is typical of an organic coating, as it contains high levels of carbon with oxygen and nitrogen also present.

Those expert in the interpretation of XPS composition data will observe that the surface composition after cleaning is typical of a clean aluminium surface. The carbon detected is due to organic species adsorbed from the atmosphere; oxygen, fluorine and phosphorus originate from the oxide overlayer on the aluminium; while magnesium, silicon and zinc originate from the aluminium substrate.

In addition to the composition after cleaning in Table D, the shape of the background distributions in the second graph in Figure 12 and the presence of plasmon loss peaks associated with the aluminium 2p and 2s photoelectron peaks confirms that metallic aluminium is close to the topmost surface of the sheet after cleaning.

There are thus described herein simple and effective embodiments of a method and apparatus for removing contaminants from the surface of the substrate.

It is believed that the method in the above described embodiments is effective, because the heat and the solvent, cleaning agent applied to the contaminant for a

prolonged period of time breaks the chemical bonds between the contaminant and the oxide on the service of the substrate. Further chemical bonds are then formed with the solvent, cleaning formulation or soap, allowing the contaminant to be easily removed.

Various modifications can be made without departing from the scope of the invention.