WO2004108300A1

WO2004108300A1 - Apparatus for applying paint and use thereof

Info

Publication number: WO2004108300A1
Application number: PCT/IB2004/002311
Authority: WO
Inventors: Jos Johannes Jules Verhoosel; Hans Meeuwissen; David George Gill
Original assignee: Sigmakalon Group; GILL, Sheila
Priority date: 2003-06-11
Filing date: 2004-06-10
Publication date: 2004-12-16
Also published as: GB0313494D0

Abstract

This invention describes the development of a novel spray paint High Volume Low Pressure (HVLP) apparatus including a membrane pump to allow for the handling of higher viscosity paint to facilitate high layer-thickness applications (typically in a single paint application) with a marked reduction in over-spray. The apparatus functions by using heated air and allows for heating of waterborne paints.. A further aspect of the present invention comprises the combination of the painting apparatus and the sprayable paint product as an effective integrated painting system.

Description

APPARATUS FOR APPLYING PAINT AND USE THEREOF

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a novel system of paint application for use both indoors and outdoors.

BACKGROUND

Paints and other types of coating materials have long been used to protect surfaces and for decorative purposes. Solvent based materials have been widely used in the past because of their durability and fast drying properties. They have over the years fallen into disfavour for interior uses because of their release of environmentally dangerous and polluting organic solvents into the atmosphere. More recently on the scene are waterbome decorative coatings which have received great applause because of their environmental friendliness. In certain jurisdictions the use of waterbome products is now mandatory for interior use as is currently the case in The Netherlands and other European countries.

Even though significant improvements have been made to waterbome paints over the years, nevertheless the application of waterbome paints is still far from perfect. For instance, especially for decorative purposes (i.e. painting interiors within the home), waterbome paints are typically applied by using traditional paint brush and roller techniques. Not only is this application method extremely time consuming, but it can be more expensive since there is often a requirement for a minimum of two (2) if not multiple layers or coatings of paint to be applied in order to achieve the desired aesthetic effect on the surface or substrate.

In applying paint, typical industry standards (and for that matter standards demanded by consumers or professional painters/decorators) are that the paint applied (whether waterbome or solvent based) to the desired surface or substrate should be of a sufficient durability and meet a minimum level of aesthetic performance in the areas of smooth coating surface (i.e. application results in a level coating surface); avoiding sagging (i.e. downward movement of the paint film between the time of application and setting resulting in an uneven surface) often caused by the paint drying too slowly or the paint being of too low viscosity or the paint film being applied in too thick a fashion. This latter performance criteria is often an issue when using standard b shing or rolling techniques. There is also a requirement that any paint applied should have a proper level of opacity caused by sufficient layer-thickness of paint. It is also highly desirable for the paint application to have a level of "cleanliness" (i.e. avoiding fouling of adjacent objects or surfaces typically accomplished through use of precise paint brush application or pre-masking for spray application of the paint).

In addition to the aesthetic requirements demanded by consumers and professional decorators there exists the need for the paint to be applied in a cost-effective and less time-consuming fashion. One of the complicating factors of the equation is that there are fewer and fewer skilled craftsmen in the painting industry and therefore the need for reducing time spent on each project as well as increasing the intervals between repainting requirements is becoming ever more critical in this industry sector.

To assist craftsmen there have been developed various means of spray painting using a gun-type apparatus. Both waterbome and solvent-based paints may be applied to a surface by atomisation in a spray gun using, for example, a high pressure medium such as compressed air often with mixed results. For traditional or standard brushing or rolling techniques it is often possible to apply a single relatively thick coating of paint of up to 200 microns but if this was attempted using a spraying technique with waterbome paints this could result in a problem. This is due to the fact that standard waterbome paints are often very slow to dry and can result in sagging on the finished surface or substrate. This problem is often worsened since standard paints are typically thinned down in order to be spray applied. As a result of these concerns, waterbome paints are rarely used in conjunction with spray painting in the decorative market. Waterbome paints are therefore still typically applied by bmsh or through use of a roller resulting in only average aesthetic results (these paints are more sensitive to brush marks and layer-thickness variations) and the expenditure of a great amount of time with the painting activity itself. Even though using of spray application techniques results in a larger area of coated surface in less amount of time than manual brush and roller applications, any economy with time is typically lost with the painstaking requirements for masking and covering any surfaces or substrates that are not desired to be coated.

The use of spray guns also creates its own series of environmental and economical concerns since it is highly desirable that any over-spray of paint and bounce-back be limited to a minimum. Another form of spraying is the so-called HNLP (High Nolume- Low Pressure). HNLP provides spray efficiency (or transfer efficiency) to substrate of between 65% and 90%, whereas conventional high-pressure spray guns typically only achieve a transfer efficiency of between 25% to 30%. HNLP though typically only works using lower viscosity/higher solvent products — thus again rules out using standard waterbome paints with HNLP as these paints are quite viscous in nature. Additionally, the application of thick paint layers of up to 200 microns are desirable for reasons of both durability and aesthetics (as well as being desirable for economic and time-saving reasons) are not possible with HNLP. Use of HNLP at present is not recommended with current waterbome products (e.g. waterbome lacquered products) because the end results is often sagging and lacks the desired smoothness. Further drawbacks with standard HNLP equipment is resulting amount of over-spray which can be considerable and limited layer-thickness build up. This would present obvious problems when a user is required to paint a large substrate area. International Patent Application PCT/GB02/05784 discloses a waterbome paint spraying apparatus in which the paint to be sprayed is heated and supplied along a hose to a spray gun. In one embodiment, the apparatus includes a turbine arranged to provide a stream of pressurised hot air which is employed to heat the paint and drive a flow of paint along a hose to the spray gun.

Currently available products and apparatuses are clearly unable to provide what craftsmen in the highly competitive decorative market truly require: rapid coverage of a desired surface or substrate through the use of apparatus other than spraying apparatus that accommodates waterbome products resulting in a surface painted to high aesthetic standards (even beyond those aesthetic standards more readily acquired through using traditional brushing and rolling techniques) with little over-spray. Such a comprehensive system does not exist at present.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention there is provided an apparatus for the application of a paint, said apparatus comprising: a pump for driving the paint through the apparatus; a turbine operable to draw air through an inlet and to heat the air which passes though it; a heat exchanger coupled to receive the paint and said heated air such that the heated air gives up a proportion of its heat to the paint before application; means for applying said paint as a coating on a substrate; and a hose coupling said heat exchanger to said means for applying said paint through which, in use, said paint passes. In accordance with another aspect of the present invention there is provided an apparatus for the application of heated paint, said apparatus comprising: means for heating the paint to be applied, and a membrane pump to drive said paint through said apparatus; means for applying said paint as a coating on a substrate; and a hose coupling said means for heating said paint to said means for applying said paint through which, in use, said paint passes.

In accordance with another aspect of the present invention there is provided an apparatus for the application of preheated paint, said apparatus comprising: a heat exchanger for heating the paint to be applied, said heat exchanger comprising a chamber for passing a heating medium and a secondary for passing paint; and a hose for carrying heated paint from said heat exchanger to means for applying said paint as a coating on a substrate, said hose comprising first and second ducts coupled respectively to said secondary and said chamber and wherein, in use, said paint passes along said first duct to the means for applying said paint and said heating medium passes along said second duct.

In accordance with another aspect of the present invention there is provided an apparatus for the application of paint, said apparatus comprising: a) a pump for driving the paint through the apparatus; b) a turbine operable to draw air through an inlet and to heat the air which passes though it; c) a heat exchanger comprising i) a first chamber which receives paint from said pump and through which said paint passes to an outlet port and ii) a second chamber which receives hot air from said turbine and through which said hot air passes to an outlet port, said first and second chambers being in thermal contact with one another such that thermal energy may be exchanged between the hot air and the paint; and d) a hose for carrying heated paint from said heat exchanger to a means for applying said paint as a coating on a substrate, said hose comprising a first second duct coupled to the outlet port of said first chamber and wherein, in use, said paint passes along said first duct to said means for applying said paint.

Advantageously, the heat of the paint is maintained until it reaches the gun or roller by the surrounding warm air in the paint hose.

The apparatus of the present invention is preferably provided with a hose which delivers heated paint to a means for applying the paint as a coating on a substrate. At least a part of said hose preferably comprises first and second ducts coupled respectively to the outlet ports of first and second chambers of a heat exchanger wherein, in use, said paint passes along said first duct to said means for applying said paint and said hot air passes along said second duct. In one embodiment, said first and second ducts both terminate at said means for applying said paint. In another embodiment, the second duct terminates short of the end of the first duct.

The means for applying said paint as a coating on a substrate is preferably other than a spray gun. Preferably, said means for applying said paint is a b sh, pad or roller. More preferably, said means for applying said paint is roller.

Preferably, the apparatus is designed so to act as a HVLP or LVLP apparatus. More preferably, the apparatus is designed so as to act as an LVLP apparatus. The apparatus of the present invention preferably comprises a membrane pump which, in use, drives said paint through said apparatus. Preferably, the membrane pump is fitted with a pulsation damper and filter unit.

The paint is preferably heated via means of an indirect heat exchanger supplied with heated air from a turbine and a paint.

Preferably, the air is heated only by being passed through said turbine. The air is preferably heated in the turbine to a temperature of from 5 to 30 °C, preferably 15 to 25 °C, more preferably about 20°C above ambient temperature.

The heat exchanger is preferably an indirect heat exchanger comprising a housing defining a vortex chamber. Preferably, the air passes through the vortex chamber. Preferably, the air enters the vortex chamber through an off centre inlet in one end of the heat exchanger wall, and leaves through an off centre outlet in an opposing heat exchanger wall. Preferably, the paint passes through a heat exchanger chamber disposed within the vortex chamber. Preferably, the heat exchanger chamber through which the paint passes is a stainless steel tube. Preferably, the vortex chamber through which the air passes is generally cylindrical.

A flexible hose of varied length preferably connects the means for applying said paint to the heat exchanger.

The apparatus of the present invention is preferably housed and/or carried on a cart.

In another aspect of the present invention, there is provided the use of the above apparatus for the application of paint as a coating on a substrate. The term "paint" as used herein is intended to cover any aqueous solution, dispersion, suspension or emulsion intended to be used to provided a protective and/or decorative coating on a substrate. It includes, without limitation, waterbome coatings such as lacquers, stains, roofing mastics and exterior and interior wall paints. Preferably, the paint is a wall paint.

The term "air" as employed herein is intended to cover any fluid, gas or liquid, which is suitable for passing through a turbine and heat exchanger and which is considered suitable for use in the present invention. Air is most preferred.

The present invention is useful for applying a waterbome paint, preferably a polyurethane modified acrylic paint, to a substrate. The waterbome paint preferably has an anti-sag index rating of between approximately 500 μm to approximately 1,100 μm. The paint preferably has a viscosity in the range of approximately 5 dPa.s to approximately 30 dPa.s when measured at a rotation speed of 181 rpm. More preferably, the paint has a low shear viscosity in the range of approximately 50 dPa.s to approximately 250 dPa.s when measured at a rotation speed of 5.6 rpm. Yet more preferably, the waterbome paint has a viscosity in the range of approximately 5 dPa.s to approximately 30 dPa.s when measured at a rotation speed of 181 rpm, a low shear viscosity in the range of approximately 50 dPa.s to approximately 250 dPa.s when measured at a rotation speed of 5.6 rpm and an anti-sag index rating of between approximately 500 μm to approximately 1,100 μm.

Preferably, the paint is applied to the substrate to provide a coating having a wet film thickness of from approximately 200 μm to approximately 700 μm .

The turbine used in the apparatus of the present invention preferably has variable speed control, to enable adaptation of the apparatus for use with a wide variety of paints with different viscosities and/or preferred application temperatures. The speed of the turbine is preferably varied from 500 rpm to 3500 rpm, preferably from 1000 rpm to 2500 rpm. Sensors may be fitted at appropriate points in the apparatus and connected to a means for controlling the turbine speed thereby to enable automatic adjustment of the turbine speed. In this way, the temperature of the air fed to the heat exchanger may be varied depending upon variances in the ambient working conditions and/or the nature of the paint to be applied. In this way, the operating speed of the turbine can be varied, depending upon the viscosity/temperature of the paint in the reservoir and the desired application viscosity. If the ambient temperature is relatively low and/or the viscosity of the paint in the reservoir is relatively high, then a relatively high turbine speed is required to generate the heat energy required to bring the paint to the appropriate application temperature/viscosity. Similarly, if the ambient temperature is relatively high and/or the viscosity of the paint in the reservoir is relatively low, then a relatively low turbine speed is required to generate the heat energy required to bring the paint to the appropriate application temperature/viscosity

Embodiments of the present invention resolves this long-felt problem through use of a combination of novel solutions to the specific problems identified above currently facing the paint and decorating industry. Embodiments of the present invention combine the use of a novel waterbome paint which may then be applied using a novel spraying apparatus resulting in a fast and efficient process as well as being aesthetically pleasing for painting large or small surface areas.

An additional aspect of the present invention comprises the combination of the above- mentioned aspects resulting in a unique and highly effective complete painting system. BRIEF DESCRIPTION OF THE DRAWINGS

The following description and the accompanying drawings referred to therein are included by way of non-limiting embodiments.

Figure 1 illustrates a paint spraying apparatus of the present invention.

Figure 2 illustrates an axial section through the heat exchanger for use with the apparatus of the present invention

Figure 3 illustrates a mobile trolley unit incorporating the paint apparatus of the present invention.

Figure 4 illustrates another apparatus for applying paint and embodying the invention.

Figure 5 illustrates a roller adapted for use with the apparatus of Figure 4.

DETAILED DESCRIPTION OF THE INVENTION

In order to overcome the aesthetic problems in using waterbome products with spraying apparatus, it has been found that pre-heating the paint material before application or atomisation results in a more uniform finish and levelling and allows a thicker coat of the paint material to be applied.

In a first embodiment of the present invention the paint material is pre-heated by means of an indirect heat exchanger. The heating medium is typically air, although not necessarily confined to this medium. After passing through the heat exchanger the heating medium is preferably supplied to the spray gun for use in atomising the preheated material. Since the heating medium thus supplies additional heat to the region of application, the quality of the coating is improved and the energy efficiency of the apparatus is increased.

The heating medium may be warmed using various methods before reaching the heat exchanger, for example by using an electrical heating element. However, it is preferred to heat the medium by passing it through a turbine. This has the advantage that it produces large volumes of heated air at a low pressure compared with a standard air compressor, thus reducing the effects of over-spray and bounce back when applying the paint material.

The indirect heat exchanger preferably has a housing which defines a vortex chamber through which the heating medium passes and the atomisable material passes through a heat-exchange conduit disposed within the chamber. The vortex chamber is preferably of a general cylindrical shape and can have concave ends. This however is certainly not mandatory and a person skilled in the art would be able to alter the overall shape or configuration without having an input on the efficiency of the vortex chamber. Specifically, the shape of the chamber creates a vortex in order that the warmed air can freely circulate around the chamber a number of times before leaving the chamber. The heat-exchange conduit is preferably coiled within the vortex chamber.

Referring to Fig. 1, paint is drawn from a reservoir (1) which can be a paint can or trough through a flexible tube (2) by means of a suitable electrically or pneumatically operated pumping mechanism (3), for example a diaphragm pump. The pump feeds the paint via a pipe (4) to be heated by passing through the secondary of an indirect heat exchanger (5). After departing from the heat exchanger the paint travels along and through a flexible hose (6) to a spray gun and nozzle (7). The length of the flexible conduit such as a hose or tube (6) may be varied in order to provide the user of the spraying apparatus a suitable length of flexible hose so as not to interfere or inhibit the mobility of the user or the apparatus. The diaphragm pump may also contain a pulsation damper and filter unit.

Atmospheric air is drawn through an inlet (10) into a turbine (11) which is driven at high speed by an electric or pneumatic motor (12).

The operating speed of the turbine can be varied, depending upon the viscosity/temperature of the paint in the reservoir and the desired application viscosity. If the ambient temperature is relatively low and/or the viscosity of the paint in the reservoir is relatively high, then a relatively high turbine speed is required to generate the heat energy required to bring the paint to the appropriate application temperature/viscosity. Similarly, if the ambient temperature is relatively high and/or the viscosity of the paint in the reservoir is relatively low, then a relatively low turbine speed is required to generate the heat energy required to bring the paint to the appropriate application temperature/viscosity. In spray-based applications, the speed of the turbine determines the amount of atomisation. The heat generation is also a result of the turbine. The turbine for instance can be a simple brash electric motor. On passage through the turbine the air is warmed typically to the order of 20°C above ambient temperature by generating friction and compression producing a large volume of warmed air at a relatively low pressure. The level of rise above ambient temperature can be dependent on the paint material being applied and therefore should be of a sufficient amount to allow a uniform finish and levelling and a thicker coat of the paint material to be applied to the substrate. This warmed air passes through a pipe (13) to the heat exchanger (5) where the air gives up a proportion of its heat to the paint passing through the secondary of the heat exchanger. Exhaust air from the heat exchanger passes along a separate duct of the hose (6) towards the spray gun and nozzle (7), where the air flow is used to atomise the warm paint into a fine spray of droplets interspersed with the warm air flow. Figure 2 illustrates a heat exchanger of the present invention. The heat exchanger has a housing (20) formed by two concave spun parts (21 and 22) providing a cylindrical side wall (23) with concave end walls (24 and 25). Warmed air from the turbine enters the chamber (26) formed within the housing through an off-centre inlet connection (27) in one of the end walls (25) and leaves through a similar off-centre outlet connection (28) in the other end wall (24). The elongated-spherical shape of the housing creates a vortex within the housing so that the air circulates around the chamber a number of times before leaving the chamber. The secondary of the heat exchanger forms a stainless steel tube (29) which is coiled into a cylindrical shape and supported co- axially within the housing (20) by means of threaded ends. It should be appreciated by one skilled in the art that use of materials other than stainless steel for the tube (29) would be acceptable.

The spraying apparatus can also be housed in a cart for ease of mobility as illustrated in Fig. 3.

Although the apparatus of the present invention has been developed based on certain principles of standard HVLP machinery, a similar design based on Low Volume Low Pressure (LVLP) would also be acceptable.

The apparatus of the present invention is preferably employs the novel paint described in International Patent Application PCT/GB02/05784, incorporated herein by reference. One of the advantages of the specially developed paint material of that application is that when used by a spraying apparatus, and in particular the novel paint apparatus of the present invention the wet film thickness reaches a typically uniform level of approximately 200 microns compared to the previous wet film thickness found in using conventional satin paint products of approximately 100 microns. The wet film thickness of standard satin paint products can be as low as 40 microns to 50 microns when sprayed, which can result in a requirement for additional layers (upwards to an extra 2 coats of paint material) being applied. This is not advantageous or cost effective for decorative or industry-related purposes.

The paint is a modified waterbome paint and must meet three criteria. The sprayable paint must possess low shear viscosity, sag resistance and satisfactory wet film thickness after spraying. For instance, the shear viscosity can be measured using a HAAKE VT181 viscosimeter using a cylindrically shaped spindle.

It was determined that a suitable viscosity at a rotation speed of 181 rpm is approximately 5 - 30 dPa.s, preferably at approximately 10 - 25 dPa.s under conditions of 23°C and 50% RH. A particularly preferred viscosity is in the region of approximately 15 - 22 dPa.s and an optimal viscosity for the higher shear at approximately 17 - 20 dPa.s. A low shear viscosity is assessed at a speed of 5.6 rpm is approximately 50 - 250 dPa.s, or preferably at approximately 80 - 200 dPa.s or more preferably at approximately 110 - 170 dPa.s with an optimal low shear viscosity of around 130-150 dPa.s.

Resistance to sagging is determined for instance using a multinotch applicator such as an ASTM D 4400 and can be analysed on an index basis. The inventors have discovered that waterbome paint suitable for spraying, particularly with the apparatus described in the present invention, should have an anti-sag index rating of between approximately 500μm to 1 lOOμm, and preferably, between approximately 700μm to approximately 800μm.

Finally, wet film thickness after spray application of the paint should range from approximately 200μm to approximately 700μm. The wet film thickness can be determined, for instance, by measurements from an ASTM D machine. Particularly preferred waterbome paints of the present invention are polyurethane modified acrylics.

Referring to Fig. 4, except for the particular differences mentioned below, the apparatus of Fig. 4 is substantially identical to the apparatus described and shown in Figs. 1-3. In this regard, a mobile cart (30) comprises a reservoir of wall paint, a membrane pump for driving the wall paint through the apparatus, a turbine and heat exchanger all as described above. A hose (31), comprising first and second duct (31, 32) coupled to the first and second outlet ports of the heat exchanger provide, respectively, conduits through which hot paint and exhaust hot air pass. The hose (31), is connected to means for applying the paint (34). The second duct, along which exhaust hot air passes, terminates a short distance from the means (34).

The means for applying paint (34) comprises a roller (35) is coupled to the hose (31) in such a manner that, in use, heated paint is passed to the inside if the roller (36). The roller (35) is provided with a plurality of holes (38) which connect the inside of the roller (36) with the exterior surface of the roller (37), as shown in Fig. 5. The inside of the roller may be provided with an Archimedes screw (39) to assist even distribution of the paint within the roller.

The surface of the roller may be provided with a conventional finish, such as a lambs wool or foam sheath, for application of the paint onto a substrate.

In use, heated paint flows from the apparatus housed on the cart (30) in the direction shown by arrows (41). The flow of paint to the roller is controlled by means of a valve control (40). In contrast to normal roller applications where the roller has to be dipped in the paint after a certain time, the disclosed apparatus with means for heating the paint can use a standard compressor to transport the paint to the roller, instead of more complex and more risky techniques like airless equipment.

As a final aspect of the present invention is the use of the novel spray painting apparatus in combination or interlinked with the novel sprayable coating material. An integrated system is a highly unique concept in the painting and decorating industry which has typically developed through the generation of so-called stand alone products or features rather than the development of integrated systems. The advantages of the claimed combination invention are in the savings in labour time and costs, limited over- spray of the paint, consistent results, and high levels of layer-thickness per application of paint thus resulting in a single application of the novel paint. The overall result of fusing the spraying apparatus and the waterbome paint of the present invention is that excellent aesthetic and technical improvements are achieved even above that observed using traditional brush and roller techniques and is delivered at a lower cost.

It will be appreciated that the features disclosed herein may be present in any feasible combination. Whilst the above description sets out the emphasis on those areas which, in combination, are believed to be new and inventive, protection is claimed for any inventive combination of the features disclosed herein.

Claims

1. An apparatus for the application of a paint, said apparatus comprising: a pump for driving the paint through the apparatus; a turbine operable to draw air through an inlet and to heat the air which passes though it; a heat exchanger coupled to receive the paint and said heated air such that the heated air gives up a proportion of its heat to the paint before application; and means for applying said paint as a coating on a substrate.

2. Apparatus for the application of heated paint, said apparatus comprising: means for heating the paint to be applied, and a membrane pump to drive said paint through said apparatus; and means for applying said paint as a coating on a substrate.

3. Apparatus for the application of preheated paint, said apparatus comprising: a heat exchanger for heating the paint to be applied, said heat exchanger comprising a chamber for passing a heating medium and a secondary for passing paint; and a hose for carrying heated paint from said heat exchanger to means for applying said paint as a coating on a substrate, said hose comprising first and second ducts coupled respectively to said secondary and said chamber and wherein, in use, said paint passes along said first duct to the means for applying said paint and said heating medium passes along said second duct.

An apparatus for the application of paint, said apparatus comprising: a) a pump for driving the paint through the apparatus; b) a turbine operable to draw air through an inlet and to heat the air which passes though it; c) a heat exchanger comprising i) a first chamber which receives paint from said pump and through which said paint passes to an outlet port and ii) a second chamber which receives hot air from said turbine and through which said hot air passes to an outlet port, said first and second chambers being in thermal contact with one another such that thermal energy may be exchanged between the hot air and the paint; and d) a hose for carrying heated paint from said heat exchanger to a means for applying said paint as a coating on a substrate, said hose comprising a first second duct coupled to the outlet port of said first chamber and wherein, in use, said paint passes along said first duct to said means for applying said paint.

5. An apparatus as claimed in claim 4, wherein at least a part of said hose comprises first and second ducts coupled respectively to the outlet ports of said first and second chambers and wherein, in use, said paint passes along said first duct to said means for applying said paint and said hot air passes along said second duct.

6. An apparatus as claimed in claim 5, wherein said first and second ducts both terminate at said means for applying said paint.

7. An apparatus as claimed in any one of the preceding claims, wherein said means for applying said paint is other than a spray gun.

8. An apparatus as claimed in any one of the preceding claims, wherein said means for applying said paint is a bmsh, pad or roller.

8. An apparatus as claimed in claim 7, wherein said means for applying said paint is roller.

9. An apparatus as claimed in any one of the preceding claims, wherein the apparatus is designed so to act as a HVLP or LVLP apparatus.

10. An apparatus as claimed in claim 9, wherein the apparatus is designed so as to act as an LVLP apparatus.

11. An apparatus as claimed in any one of the preceding claims, comprising a membrane pump for driving said atomisable material through said apparatus.

12. An apparatus as claimed in clam 11, in which the membrane pump is fitted with a pulsation damper and filter unit.

13. An apparatus according to any one of the preceding claims, in which the paint is heated via means of an indirect heat exchanger supplied with heated air from said turbine and said paint.

14. An apparatus according to any of the preceding claims, in which the air is heated only by being passed through said turbine.

15. An apparatus according to any one of the preceding claims, wherein the air is heated in the turbine to a temperature of from 5 to 30 °C, preferably 15 to 25 °C, more preferably about 20°C above ambient temperature.

16. An apparatus according to any one of the preceding claims, in which the heat exchanger is an indirect heat exchanger comprising a housing defining a vortex chamber.

17. An apparatus according to Claim 16, wherein the air passes through the vortex chamber.

18. An apparatus according to Claim 17, wherein the heating medium enters the vortex chamber through an off centre inlet in one end of the heat exchanger wall, and leaves through an off centre outlet in an opposing heat exchanger wall.

19. An apparatus according to any one of Claim 16 to 18, wherein the paint passes through a heat exchanger chamber disposed within the vortex chamber.

20. An apparatus according to Claim 19 in which the heat exchanger chamber is a stainless steel tube

21. An apparatus according to any one of Claims 16 to 20, wherein the vortex chamber is generally cylindrical.

22. An apparatus according to any one of Claims 1 to 21, wherein a flexible hose of varied length connects the means for applying said paint to the apparatus.

23. An apparatus according to any of Claims 1 to 22, housed and/or carried on a cart.

24. The use of an apparatus as claimed in any one of Claims 1 to 23, for the application of paint.

25. The use of an apparatus as claimed in claim 24, wherein the paint is applied other than by spraying.

26. The use as claimed in claim 25, wherein the paint is applied by a bmsh, pad or roller.

27. The use as claimed in claim 26, wherein the paint is applied by a roller.

28. The use of an apparatus as defined in any one of Claims 25 to 27, wherein the paint is a waterbome paint, preferably a polyurethane modified acrylic paint.

29. Use as claimed in Claim 28, wherein the waterbome paint has an anti-sag index rating of between approximately 500 μm to approximately 1,100 μm.

30. Use as claimed in claim 29, wherein the waterbome paint having a viscosity in the range of approximately 5 dPa.s to approximately 30 dPa.s when measured at a rotation speed of 181 φm, a low shear viscosity in the range of approximately 50 dPa.s to approximately 250 dPa.s when measured at a rotation speed of 5.6 φm and an anti-sag index rating of between approximately 500 μm to approximately 1,100 μm.

31. Use as claimed in claim 28, wherein the paint has a viscosity in the range of approximately 5 dPa.s to approximately 30 dPa.s when measured at a rotation speed of 181 φm.

32. Use as claimed in Claim 29 or Claim 31 having a low shear viscosity in the range of approximately 50 dPa.s to approximately 250 dPa.s when measured at a rotation speed of 5.6 φm.

33. Use as claimed in any one of Claims 24 to 32, wherein the paint is applied to the substrate to provide a coating having a wet film thickness of from approximately 200 μm to approximately 700 μm .

34. Use as claimed in any one of claims 24 to 34, wherein the turbine speed is varied from 500 φm to 3500 φm, preferably from 1000 φm to 2500 φm.