GB2552719A

GB2552719A - Temperature modification element and its method of forming

Info

Publication number: GB2552719A
Application number: GB1613545.1A
Authority: GB
Inventors: Black Stuart
Original assignee: Qse Metalblast Ltd
Current assignee: Qse Metalblast Ltd
Priority date: 2016-08-06
Filing date: 2016-08-06
Publication date: 2018-02-07

Abstract

A temperature modification element 10 comprises a recess wall 108 of a recess 112 formed in a substrate 184 wherein is contained a thermal device 116, such as an electrically heated wire or a pipe or tube for connection to a source of fluid, and a filler 120 comprised of fused droplets having a face contiguously joined to the thermal device and to the recess wall. Also disclosed is a method of manufacturing the temperature modification element in which the thermal device is encapsulated in the recess by thermal spraying of liquid or molten droplets into the recess such that they solidify on contact with the device and substrate. The filler material may be a metal applied by an arc spraying process. The substrate may be a portion of an aircraft fuselage, wing or engine nacelle or a portion of a refrigerator evaporator.

Description

(71) Applicant(s):

Qse Metalblast Ltd

Cowley Road, POOLE, BH17 0UJ, United Kingdom (56) Documents Cited:

GB 2517465 A GB 2014417 A

GB 1385273 A GB 1384235 A

GB 1181216 A US 4415798 A

US 20060243412 A1 (72) Inventor(s):

Stuart Black (74) Agent and/or Address for Service:

ipconsult

21A Commercial Road, SWANAGE, Dorset, BH19 1DF, United Kingdom (58)

Field of Search:

INT CL B64D, F25B, H05B Other: Online: WPI, EPODOC (54) Title of the Invention: Temperature modification element and its method of forming Abstract Title: Temperature modification element and method (57) A temperature modification element 10 comprises a recess wall 108 of a recess 112 formed in a substrate 184 wherein is contained a thermal device 116, such as an electrically heated wire or a pipe or tube for connection to a source of fluid, and a filler 120 comprised of fused droplets having a face contiguously joined to the thermal device and to the recess wall. Also disclosed is a method of manufacturing the temperature modification element in which the thermal device is encapsulated in the recess by thermal spraying of liquid or molten droplets into the recess such that they solidify on contact with the device and substrate. The filler material may be a metal applied by an arc spraying process. The substrate may be a portion of an aircraft fuselage, wing or engine nacelle or a portion of a refrigerator evaporator.

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

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TEMPERATURE MODIFICATION ELEMENT AND ITS METHOD OF FORMING

Field of the Invention

This invention relates generally to a method for forming a temperature modification element. More particularly the invention relates to an element formed by spraying molten droplets so as to form a heater and/or a cooling element, wherein a thermal device, such as trace heater or cooler, is encapsulated and protected by a recess wall and a filler formed by the molten droplets.

Background

When aircraft fly at high altitudes, there is a risk of water or fuel lines freezing. When this occurs flow is impeded and can expansion due to freezing can rupture the lines. Also frost which forms on refrigerator heat evaporators reduces operative efficiency of the evaporators. Ice which forms on aircraft wings and aircraft engine nacelles is a hazard to flight.

Prior Art

In order to overcome the above problems techniques were developed to wrap a pipe with a trace heating device, such as an electrical resistance wire heater; applying a composite ribbon or sheet heater to an aircraft wing skin by gluing the ribbon to the skin; or inserting immersion heaters into a liquid reservoir.

Wrapped trace heater and glued sheet heaters were placed only one side in contact with the assembly to be heated. The result was heaters suffered significant heat waste to the surrounding air.

Wrapped trace heaters and glued sheet heaters are also prone to damage from physical impact and environmental exposure.

Immersion heaters are impractical for preventing build-up of ice on a surface where the ice forms directly without forming any reservoir of liquid in which to immerse the immersion heater.

An object of the invention is to provide an improved temperature modification element that does not suffer from problems encountered in prior art devices.

Summary of the Invention

According to a first aspect of the present invention there is provided a method of 5 forming a temperature modification element comprising the steps of: encapsulating a thermal device in a recess in a substrate by spraying liquid or molten droplets into the recess such that they solidify on contact with the device and substrate.

The filler is thereby formed by spraying liquid or molten droplets into the recess such that the thermal device is advantageously arranged for heating and/or cooling by heat conduction through the filler to a substrate in which the recess is contained.

The method forms a high efficiency temperature modification element in which the thermal device is protected from contact such as rubbing which could otherwise damage the thermal device.

Preferably the molten droplets are formed by melting a metal or a ceramic so as to form 15 molten metal droplets or molten ceramic droplets respectively. Advantageously a metal filler formed depositing molten metal droplets is ductile, strong, and a heat conductor. Advantageously a metal filler formed depositing molten metal droplets is, strong, does not corrode or rust, and is a heat conductor.

Preferably the method includes an additional step of forming the recess with surfaces, 20 which flare apart from a line of convergence, to an opening or rim of the recess.

Hence preferably the method includes forming the recess in the substrate by forming the surface. Preferably the surfaces form an external portion of a wall defining the recess. Preferably the surfaces are formed by cutting, grinding, milling, or routing into the substrate, or indenting the substrate.

Preferably the method further includes a step of spraying molten droplets in a stream, substantially normal to the surfaces which flare apart.

Preferably the method includes a step of forming the molten droplets by melting material with heat from an electric arc.

Preferably the method includes a step of forming the molten droplets by melting material with heat from a flame fueled by a mixture of a flammable gas and oxygen.

Preferably the method includes a step of mixing the flammable gas and oxygen in a ratio wherein the proportion of the flammable gas exceeds the stoichiometric proportion for complete combustion of the flammable gas.

Preferably the method includes a step of sweeping a spray nozzle thereby displacing and/or rotating the nozzle so as to spray the droplets such that the droplets are deposited from the recess wall to the thermal device.

Preferably the method includes a step of wherein the droplet sprayed to deposit a layer of fused molten droplets, the layer having a thickness in the range of .02 mm and .03 mm to form a portion of the filler.

Hence the layer forms a portion of the filler.

Preferably the method includes abrading the recess wall to impart a preselected surface roughness on the wall in order to improve adhesion with the metal layer deposited.

Preferably the method includes grit blasting the recess wall to impart a preselected surface roughness on the wall.

Preferably the method includes forming the recess in a substrate; the substrate comprising or adjoining a conduit for a thermal working fluid.

Preferably the method includes forming the temperature modification element in a portion of a refrigerator evaporator.

Preferably the method includes forming the temperature modification element in a portion of an aircraft fuselage skin or aircraft wing skin or aircraft engine nacelle or aircraft fuel system.

According to a second aspect of the invention there is provided a temperature modification element comprising: a thermal device encapsulated by a recess in a substrate and a filler in contact with the device and the substrate.

Preferably the filler thereby occupies the recess such that advantageously the thermal device is arranged for heating and/or cooling by heat conduction through the filler to a wall of the recess.

Preferably the thermal device and the recess wall are in direct contact one with 5 another.

Preferably the filler fixes the thermal device in position in the recess.

Preferably the filler fills a volume of the recess intermediate the recess wall and the thermal device.

Preferably the recess wall has surfaces which flare apart from a line of convergence to 10 an opening or rim of the recess. Preferably the surfaces are slanted such that the recess wall defines a V-profile. Preferably the recess wall includes a substantially

U-shaped profile replacing the tip of the V-shaped profile so that the slanted surfaces flare apart from the U-shaped profile opening or rim.

Preferably the portion of the recess having the U-shaped profile opening contains the 15 thermal device. Preferably an external surface of the thermal device is flush with a plane spanning the U-shaped profile opening, or a plane across the brim of the

U-shaped profile opening.

Preferably the thermal device comprises a hollow tube. Preferably the temperature modification element comprises a means of supplying the hollow tube with fluid, wherein the means passes through the recess wall or the filler.

Preferably the thermal device comprises a wire. Preferably the temperature modification element comprises a means of supplying the wire with electrical current, wherein the means passes through the recess wall or the filler. Preferably the wire is sheathed in an electrical insulator sheath.

Preferably the thermal device comprises a thermally conductive shield.

Preferably in the temperature modification element the recess is located in a substrate comprising or adjoining a conduit for a thermal working fluid.

According to another aspect of the invention there is provided a portion of a refrigerator evaporator comprising a temperature modification element as described herein.

According to another aspect of the invention there is portion of an aircraft fuselage skin or aircraft wing skin or aircraft engine nacelle or an aircraft fuel system including a temperature modification element as described herein.

According to another aspect of the invention there is provided a thermal heat exchanger comprising a temperature modification element as described herein.

Preferably the exchanger comprises a first plate comprising the recess.

Preferably in the exchanger the recess is located adjacent to a conduit for a thermal 10 working fluid, wherein the conduit is in or connected to the plate.

Preferably the exchanger is arranged wherein the recess is interspersed with conduit for a thermal working fluid, wherein the conduit is in or connected to the plate.

Preferably the exchanger comprises a first plate and a second plate joined face to face, wherein the first plate comprises the recess.

Preferably the exchanger is arranged such that the recess is arranged such that the recess has a rim on the exchanger exterior.

Preferably the exchanger is arranged wherein the recess is arranged such that the recess has a rim on a face of the second plate that is joined to a face of the first plate.

Preferably the exchanger is arranged wherein the thermal device comprises a power 20 connection means whereby the thermal device is connectable to a source of current of fluid or electricity, whereby heat is conducted in use from the thermal device to the plate to defrost the plate or to prevent formation of ice on the plate.

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

Brief Description of the Figures

Figure 1 is front view of an aircraft comprising a temperature modification element on a wing and on an engine nacelle;

Figure 2 is an isometric view of an engine nacelle comprising a temperature modification element;

Figure 3 is a cross section of a wing aerofoil comprising a temperature modification 5 element;

Figure 4 is a view of a top of a wing comprising a temperature modification element;

Figure 5 is a second cross section of a wing aerofoil comprising a temperature modification element;

Figure 6 is a second view of a top of a wing comprising a temperature modification 10 element;

Figure 7 is a view of ship comprising a temperature modification element;

Figure 8 is a plan view of a heat exchanger comprising a temperature modification element;

Figure 9 is a first cross section through a temperature modification element looking 15 along an axis parallel to the lengthwise direction of the recess;

Figure 10 is a view of the exposed surface of a filler of a temperature modification element;

Figure 11 is a second cross section through a temperature modification element looking along an axis perpendicular to the lengthwise direction of the recess;

Figure 12 is third cross section through a temperature modification element illustrating heat conduction pathways;

Figure 13 is a fourth cross section through a temperature modification element illustrating a thermal device comprising a tube;

Figure 14 is a fifth cross section through a temperature modification element illustrating 25 contact between the thermal device and a U-shaped profile recess wall;

Figure 15 is a sixth cross section through a temperature modification element illustrating a recess with V-shaped profiled-shaped profile;

Figure 16 is a seventh cross section through a temperature modification element illustrating a recess with a combined U and V-shaped profile;

Figure 17 is an eighth cross section through a temperature modification element illustrating a thermal device flush with rim of U recess;

Figure 18 is a cross section view through substrate showing rough surface of recess wall;

Figure 19 is a cross section view through substrate and thermal device illustrating method of placing device in recess;

Figure 20 is a cross section through a heat exchanger comprising two panels forming a recess for a temperature modification element and a conduit for refrigerant; and

Figure 21 is a thermal device for a temperature modification element.

Detailed Description of the Invention

Referring to the Figures, there is shown in Figure 1 an aircraft comprising a wing 910 and an engine slung below the wing. One use of the temperature modification element of the invention is de-icing aircraft wings and aircraft engine nacelles.

As shown in Figure 1, the leading edge of wing comprises a temperature modification element 10. In Figure 1 the filler 120 of the temperature modification element is visible as a strip. The filler has a first end proximate the wing root and a second end proximate to the wing tip.

Also shown in Figure 1 is an aircraft engine nacelle 920. The nacelle comprises a temperature modification element 10 arranged to follow a portion of the circumference.

Figure 2 shows a nacelle 920 comprising two temperature modification elements according to the invention. The temperature modification element comprises a recess wall in a skin of the nacelle. The recess wall defines of a recess wherein is contained a thermal device, and a filler comprised of fused droplets formed by filling the recess with molten droplets sprayed into the recess. The filler has a face contiguously joined to the thermal device and to the recess wall.

A detailed view of an embodiment of the thermal device 116 is shown in Figure 21. The thermal device comprises an electrical wire 117 which in use is heated by electric current. The heater wire comprises means to connect electrical wire to a source of electricity. The means is a wire connector 118 as shown.

Another embodiment the thermal device comprises a pipe or a tube having a means to for connection to a source of fluid. In use the fluid has a preselected temperature so that the thermal device is relatively hot or cold compared to the substrate material in which recess is situated.

One of the temperature modification elements 10 is arranged along a portion of the circumference of the nacelle. The other of the temperature modification elements 10 is arranged longitudinally along the nacelle. The temperature modification element has an outline of strip defined by the filler 120 over the recess. The leading end of the filler is located at a leading edge of the nacelle. The filler 120 long axis is aligned with the longitudinal axis of the nacelle. The recess of the element opens to the exterior surface of the nacelle so that the filler 120 over the recess is visible in has a trailing edge proximate the trailing edge of the nacelle.

Figure 3 shows an aerofoil cross section profile of an airplane wing 910, and Figure 4 shows a view of the top surface of the wing 910. The wing comprises a temperature modification element 10. The temperature modification element 10 comprises a recess wall 108 in skin of the wing. The recess wall defines a recess wherein is contained a thermal device 116, and a filler 120 comprised of fused droplets having a face contiguously joined to the thermal device and to the recess wall. The recess is aligned with the leading edge of the wing. Figure 4 shows the filler 120 of the temperature modification element has the form of a strip which has relative long length compared to a relatively narrow width. The temperature modification element is aligned so that the filler 120 which fills the recess and thermal device 116 is aligned substantially parallel with the leading edge of the wing.

Figure 5 shows another aerofoil cross section profile of an airplane wing 910. The airplane wing shown in Figure 5 has a temperature modification element wherein the recess is aligned substantially perpendicular to the leading edge of the wing. The filler 120 over the recess and thermal device 116 is shown in Figure 6. Figure 6 shows a wing 910 comprising a plurality of temperature modification elements 10 on the skin of the wing. The recess wall of the element opens to the skin surface and is occupied by the filler 12. The plurality of elements 10 are aligned so that the recess walls are parallel.

The temperature modification elements extend to both the topside and the bottom side of the wing. In use the thermal device is activated to transfer heat by conduction through the filler to the wing skin. The heat transferred warms the wing skin, thereby preventing frost from forming on the wing skin or de-icing the wing skin of ice.

A ship is shown in Figure 7. In arctic regions a ship superstructure and ship deck tend to be cooled to a temperature below freezing by cold wind. Sleet freezes on the deck and superstructure. Waves which splash onto the ship deck and superstructure also freeze. Hence ice builds up on the ship deck and superstructure which makes the ship top heavy. The ship becomes prone to capsize disaster.

To prevent ice freezing on the ship deck and superstructure, Figure 7 shows temperature modification elements are built into plates which form the ship deck and superstructure. The temperature modification element 10 comprises a recess wall in a plate of the ship deck or superstructure. The recess wall defines a recess in the plate. In recess is contained a thermal device, and a filler comprised of fused droplets having a face contiguously joined to the thermal device and to the recess wall. The filler provides protection for the thermal device. The deck can be walked upon and for working ships, heavy equipment such as fork lifts can be driven over the deck. The filler protects the thermal device from damage from walking boots, fork lift wheels, and cargo which may be dragged across the deck.

Where ship deck plates comprise ferrous metal or alloy, such as steel, the filler is formed of fused ferrous metal or alloy droplets. Where an aircraft wing skin or nacelle skin is formed of aluminium metal or alloy the filler is formed of fused aluminium or aluminium alloy droplets. Where a heater exchanger panel or pipe comprises stainless steel, the filler is formed of fused stainless steel droplets. Other combinations are possible because the process by which molten droplets are sprayed into the recess is versatile. The molten droplets cool rapidly when they are sprayed onto the recess surface. Hence the recess surface is not necessarily adversely affected by the molten droplets. For example, where a wing skin or boat plate is made of a graphite fibre polymer matrix composite or glass fibre polymer matrix composite, the fused droplets may comprise a metal or metal alloy.

Another application of the temperature modification element 10 is defrosting a refrigerator evaporator. A plan view of a refrigerator evaporator 940 is shown in Figure 8. A refrigerator adaptor is a heat exchanger. The heat exchanger comprises a plate 188. The plate has faces with a large area for transferring heat with a fluid in which the plate is immersed such as air or water.

As shown in Figure 8 the plate supports a conduit 192 for a working fluid as ammonia or another refrigerant. The conduit follows a serpentine path on the plate. The refrigerant evaporates in the conduit which makes the plate cold. Frost and ice tends to form on the plate 188 and conduit 192 which reduces heat exchange efficiency.

As shown in Figure 8, there is a temperature modification element 10 on the plate 188. The temperature modification element 10 is located adjacent the conduit 192. The temperature modification element is arranged adjacent to the conduit. The temperature modification element and the conduit are arranged so that the lengthwise dimensions are parallel and side by side.

The plate 188 forms the substrate for the recess wall 108. The recess 112 provides a volume wherein heater conductor 117 of the thermal device. In a method of manufacturing the heat exchanger, the heater conductor is a wire which is sheathed in an electrical insulation. The sheathed wire is placed in the recess. The sheathed wire is coated by filler 120. The filler provides protection for the thermal device including sheathed wire.

An aperture 189 through the recess wall 108 in the plate 188 is located to open into the recess 112 and to exit from the plate. A portion of a wire connector 118 is passed through the aperture 189 to connect the heater conductor 117 to an electrical current source external to the plate.

As shown in Figure 8, the serpentine path of the conduit defines rows on the plate. Temperature modification elements 10 are interspersed between the rows of the serpentine conduit. In use the temperature modification element heats and defrosts both the plate and the conduit which improves the efficiency of the evaporator as a heat exchanger.

Generally, the fused droplets which form the filler comprise the same or similar metal or alloy as the substrate in which the recess wall is formed. For example, where a substrate plate or panel is comprised of iron, steel, aluminium, nickel, chromium, titanium, molybdenum, silver, gold, lead, or uranium, then the fused droplets are comprised of the same metal or alloy. A substantial match of coefficient of thermal expansion, strength, toughness, corrosion resistance, abrasion resistance, appearance, and so forth between the substrate and filler is thereby provided. However, in some applications it may be better for the substrate and the filler to be different materials. In particular, filler formed from a valuable metal or alloy may be ideally sprayed onto a recess wall formed in substrate of relative less expensive metal or alloy.

There is a method for forming the filler 120 of the temperature modification element. The method is versatile in that it is effective for structures such as the aircraft wing skin, boat deck, heat exchanger plate, and the like. The method may be applied to a separate skin or plate, or in situ on a ship, boat, or heat exchanger in service.

Figure 9 shows a structure providing a substrate 184. The substrate has a recess wall 108 defining the recess 112 wherein is contained a thermal device. An example of a thermal device comprising a conductor 168 sheathed electrical insulation 172 is shown in Figure 21.

The method of making the temperature modification element includes inserting an electrical wire 168 sheathed in electrical insulation 172 as the thermal device 116 in the recess 112 and forming a layer of the filler 120 by spraying molten droplets onto the electrical insulation. Molten droplets are sprayed so as to form a filler of fused droplets. The filler 120 is thereby formed contiguous with the recess wall 108 and the filler 120 coats the thermal device.

As shown in Figure 14, the filler 120 is a metal sprayed recess filler. It is comprised of fused droplets intermediate a first face 124 opposite a second face 125, wherein the first face is contiguously joined to a thermal device 116 and to a recess wall 108 defining a recess 112 containing the thermal device 116.

In an embodiment of the method forming the filler, a layer of molten droplets having a thickness in the range of .02 mm to .03 mm is formed by spraying the droplets in a stream which is swept laying down a layer for filter material from one edge of the filler to another edge. By sweeping the stream back and forth the filler is formed comprising a plurality of layers of fused droplets. A stack of layers is made by successive spray passes so the filler has a thickness in a range from .080 mm to .120 mm thick.

Heat from an electric source melts metal-spray material to form the molten droplets.

The metal spray material is melted by a heat source. The liquid or molten material is then propelled by process gases and sprayed onto a base material where it solidifies and forms a solid layer.

A suitable process is electric arc spray. The heat source is an electric arc. In a device comprising a nozzle the electric arc is formed by contact of two opposite charged metallic wires. The electric arc melts the tip of the wires. Typically, the wires are of the same composition.

Compressed gas such as air is forced through the device at high speed. The flow of compressed air atomizes the metal melted from the tip of the wires. The compressed gas blows the atomized metal at high speed through the nozzle. To reduce oxidation of the atomized metal gases such as argon or nitrogen are mixed with the air or substituted for the air.

The rate of spray is regulated in part by the rate of wire feed. It is also regulated part by control of the voltage and/or current between the wire tips so a constant arc can be maintained.

The filler is applied as a coating by means of a special device through which melted or molten spray material is propelled at high speed onto a cleaned and prepared component surface.

A range of diameters of the metal droplets and particles sprayed is from 20 micrometers to 500 micrometers.

Because adhesion of the coating to the substrate predominantly consists of mechanical bonding, the surface to be coated is cleaned. The surface is roughened using a blasting procedure which increases the surface area for bonding of the sprayed particles.

The sprayed particles are liquid or molten coating particles which impact the surface at high speed. This causes the particles to deform and spread like pancakes on the substrate. As the particles shrink and solidify, they bond to the roughened base material. Adhesion of the coating is therefore based on mechanical hooking.

In some embodiments the thermal device is sheathed in a thermally conductive medium such as a ceramic or mica fibre which is both thermally conductive and electrically resistive. The thermally conductive medium forms a shield and external surface of the thermal device 116. The molten droplets are sprayed onto the thermally conductive sheath for efficient heat conduction. Spraying molten droplets onto a surface makes an interface between a filler of fused droplets and the surface which is efficient for heat conduction.

Figure 10 shows a view looking directly at the filler which has been sprayed onto the substrate 184 thereby occupying and covering the recess and thermal device contained therein.

Figure 11 shows the cross-section A-A which is indicated in Figure 9. The filler 120 which is formed from fused metal droplets coats the sheath 172 of electrical insulation 172. The sheath 172 electrically insulates the conductor 168 of the thermal device 116 from the filler 120. The sheath 172 also insulates the conductor 168 from the substrate 184.

As can be seen from Figure 8, Figure 10, and Figure 11, the recess is an elongate channel. The recess has a lengthwise dimension which is relatively longer than either the recess width or the recess depth.

In an embodiment, the recess wall 108 is formed on the substrate 184, and the substrate 184 and the filler 120 of fused droplets consist of the same material. In another embodiment the recess wall 108 is formed on a substrate 184, and the substrate 184 comprises a first material and the filler 120 of fused droplet comprises a second material. In some embodiments the recess wall is formed on a substrate 184 of a metal or metal alloy. In some embodiments the recess wall is formed on a substrate of polymeric material or a composite material comprising a polymeric material.

The method includes spraying molten droplets into a space of recess 108 intermediate he thermal device 116 and the recess wall 108. As shown in Figure 12, the filler 120 thereby penetrates into the recess intermediate the thermal device and the recess wall 108. Heat conducts from thermal device 116 from through the filler 120 to the recess wall 108 and thereby into the substrate 184. Heat also conducts from the thermal device 116 directly to the recess wall deep surface 109 because the thermal device 116 is in direct contact with the deep surface 109. As in the embodiment shown in Figure 12, heat is conducted in three directions from the thermal device 116 into the substrate 184. Heat is also conducted from the surface of the thermal device which is exposed by the recess opening and coated by the fused droplets when the filler is sprayed. The method of spraying molten droplets into the recess to form the filler therefore provides for efficient heat conduction between a majority of surface area of the thermal device and the substrate.

An alternative version of the method is particularly suitable for composite or other polymeric substrates. It is also suitable for application with metal substrates, especially to prevent galvanic corrosion of the filler and/or substrate. It includes filling in the recess with a filler of polymeric material.

To improve thermal heat conductivity metal particle are mixed with the to enhance thermal conduction through the filler

The method includes melting a thermoplastic plastic material with a heat source. A compressed gas atomizes the melted thermoplastic material and sprays atomized particles of into the recess so as to form the filler covering a heating wire in the recess.

In addition or alternatively, the method includes mixing materials such as a liquid resin and a liquid hardener to make a thermosetting polymer. While still in a liquid state, the thermosetting polymer is atomized by a compressed gas and sprayed into the recess to form the filler covering a heating wire in the recess.

The thermosetting polymer subsequently sets into a solid state in the recess or the thermoplastic polymer subsequently freezes into a solid state in the recess.

Figure 13 shows a thermal device which is a hollow tube 164 for transporting a working fluid. A method for manufacturing the temperature modification element 10 includes inserting the tube 164 as the thermal device 116 into the recess 112 such that the axial length of the tube is substantially aligned with the linear length of the recess.

In use the working fluid in the tube is either hotter or colder than the substrate and so heat is transferred from the fluid by conduction through the tube 164 and through the filler 120 which coats the tube. The heat is transferred from the filler 120 and into the substrate 184. The process of forming the filler 120 by spraying fused droplets into the recess 112 provides for coating and covering thermal devices of various shapes whether rectangular in cross-section as shown in Figure 9 and Figure 12, or round in cross section as shown in Figure 13, or even an irregular shape because the molten droplets conform to the surface of the thermal device whatever the shape.

As shown in Figure 14 in one embodiment the of the temperature modification element 10 the recess wall has surfaces which are parallel. Molten droplets are sprayed into the recess 112 coating the recess wall parallel surfaces thermal device with fused droplets.

In another embodiment of the temperature modification device the recess wall has surfaces which flare apart. In some embodiments the surfaces flare apart from a line of convergence to an opening or rim 110 of the recess.

As shown in Figure 15 in one embodiment the recess wall has surfaces which are slanted defining a V-profile in the structure. The process of making the temperature modification device includes forming the recess in the substrate 184 with slanted walls. Recess wall slanted surfaces which flare apart to the opening or rim 110 provide for spraying the molten droplets directly at the recess wall. The molten droplets are sprayed in a stream substantially normal to the slanted surface of the recess wall. A nozzle of a spray gun is able to remain exterior to the recess and spray the droplets in a stream normal to the slanted surfaces which flare apart.

As shown in Figure 16, one embodiment of the method of manufacturing the temperature modification element 10 includes forming the recess wall 108 with a substantially U-shaped profile replacing the tip of the V-shaped profile. Figure 16 illustrates the profile of the recess wall with the combined U-shaped and V-shaped profiles. The slanted surfaces 132 of the V-shaped profile flare apart from the U-shaped profile opening or rim 152.

As shown in Figure 17, a ledge 144 is formed connecting the rim 152 of the U-shaped profile and the slanted surfaces extending to the rim 110 of the recess. The ledge 144 is substantially perpendicular to the U-shaped profile surface at the edge of the U-shaped profile rim 152. The portion of recess having the U-shaped profile contains the thermal device 116 and the molten droplets are sprayed into the recess so as to form the filler 120 attached contiguous with the ledge. As the ledge 144 is normal to the U-shaped profile at the rim 152, the filler may be formed by a nozzle exterior to the recess directing a stream of droplets into the recess normal to the ledge.

Molten droplets directed in a stream normal to a surface such as the ledge adhere well to the surface because the normal impact drives the droplets deep into crevasses defined by asperities on the surface. By spraying the molten droplets into the recess the filler 120 is formed coating the U-shaped profile of the recess wall and the thermal device 116 so as to provide a heat conduction path to the substrate 184 through the fused droplets. The molten droplets also coat the slanted surfaces of the recess wall.

In some embodiments such as shown in Figure 16 and Figure 17 the molten droplets are sprayed into the recess until the filler 120 overflows the rim 110 of the recess.

A recess 112 formed by an alternative method is illustrated in Figure 20. A first panel

190 and a second panel 191 are joined face to face. The joined by a brazing material or an adhesive 196. Through the first panel is a slot. The slot has walls which form a portion of the recess wall 108. A portion of the second panel forms the deep surface 109 of the recess wall. This method may be used in conjunction with fabrication of the heat exchanger shown in Figure 8. An indent is made in the face of the first panel 190 or the second panel 191 so that when the first or second panels are joined face to face the conduit 192 for a refrigerant fluid is formed. The recess 112 and the conduit 192 are both formed in a single step of placing the first panel 190 and the second panel 191 face to face.

In some embodiments such as shown in Figure 15, the thermal device 116 is placed into the recess where it rests against the recess wall 108 such that an external surface of the thermal device 116 is flush with a plane 149 spanning the V-shaped profiled-shaped profile opening or rim 110. In other embodiments such as shown Figure 16 the thermal device is placed into the recess where it rests against the recess wall 108 such that an external surface of the thermal device is flush with the rim 110 of the recess opening. In another the thermal device 116 is placed into the recess where it rests against the recess wall 108 such that an external surface of the thermal device is flush with a plane 141 spanning the rim 152 of the U-shaped profile opening.

Good adhesion between the fused droplets of the filler and the recess wall is obtained by forming the recess wall such that it has preselected surface asperities connecting the filler to the recess wall. Figure 17 illustrates a recess wall 108 with a roughened surface. The molten droplets are sprayed onto the rough recess wall. The molten droplets penetrate into crevasses on the rough wall and then the droplets fused together to form the fused droplets of the filler. The fused droplets are thereby engaged with asperities and crevasses on the recess wall surface thereby connecting the filler to the recess wall.

A preselected surface roughness of the recess wall is obtained by abrading the recess wall with sandpaper, or with a wire brush, or with a stone grinder, or by grit blasting the recess wall.

The thermal device 116 also has an external surface having a preselected surface roughness. As shown in Figure 18, the thermal device 116 is placed in the recess

112. The molten droplets are then sprayed onto the rough surfaces of the recess wall and the thermal device to form the filler.

The invention has been described by way of examples only. Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the claims.

Index of Labelled Features in Figures aircraft engine nacelle .................................................................. 920 airplane wing .............................................................................. 910 braze or adhesive ......................................................................... 196 recess rim .................................................................................. 156 recess wall - ledge ........................................................................ 144 recess wall - U rim ......................................................................... 152 recess wall - U surface .................................................................... 140 recess wall - V rim .......................................................................... 148 recess wall - V surface ..................................................................... 136 conduit ............................................................................................ 192 conduit inlet/outlet .............................................................................. 193 filler ............................................................................................... 120 filler first face .................................................................................. 124 filler second face .............................................................................. 125 first panel ........................................................................................ 190 flared surface .................................................................................... 132 heat exchanger .................................................................................. 940 plane spanning U rim .......................................................................... 141 plane spanning V rim .......................................................................... 149 plate ................................................................................................ 188 plate aperture ................................................................................. 189 second panel ................................................................................... 191 ship superstructure ........................................................................... 930 substrate ......................................................................................... 184 thermal device - conductor ............................................................... 168 thermal device - electrical insulation .................................................... 172 thermal device - sheath .................................................................... 180 thermal device - thermally conductive shield ......................................... 176 thermal device - tube ....................................................................... 164 volume intermediate wall and element .................................................. 128

Claims

Claims:

1. A method of forming a temperature modification element comprising steps of: encapsulating a thermal device in a recess in a substrate by spraying liquid or molten droplets into the recess such that they solidify on contact with the device and substrate.

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2. A method according to claim 1 including a step of forming the recess with surfaces which flare apart from a line of convergence to an opening or rim of the recess.

3. A method according to claim 2 including a step spraying the molten droplets in a stream substantially normal to the surfaces which flare apart.

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4. A method according to any preceding claim including a step forming the molten droplets by melting material with heat from an electric arc.

5. A method according to any of claims 1 to 3 including a step of forming the molten droplets by melting material with heat from a flame fueled by a mixture of a flammable gas with oxygen.

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6. A method according to claim 5 including mixing the flammable gas and oxygen in a ratio wherein the proportion of the flammable gas exceeds the stoichiometric proportion for complete combustion of the flammable gas.

7. A method according to any preceding claim including sweeping a spray nozzle thereby displacing and/or rotating the nozzle so as to spray the droplets such that the

20 droplets are deposited from a wall of the recess to the thermal device.

8. A method according to claim 7 where the droplets are sprayed to deposit a layer of fused molten droplets, the layer having a thickness in the range of .02 mm and .03 mm to form a portion of the filler.

9. A method according any preceding claim including abrading a wall of the

25 recess to impart a preselected surface roughness on the wall.

10. A method according to any preceding claim including grit blasting a wall of the recess wall to impart a preselected surface roughness on the wall.

11. A method according to any preceding claim including forming the recess in a substrate; the substrate comprising or adjoining a conduit for a thermal working fluid.

12. A method according to any preceding claim including forming the temperature modification element in a portion of a refrigerator evaporator comprising the substrate.

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13. A method according to any preceding claim including forming the temperature modification element in a portion of an aircraft fuselage skin or aircraft wing skin or aircraft engine nacelle or aircraft fuel system comprising the substrate.

14. A temperature modification element comprising: a thermal device encapsulated by a recess in a substrate and a filler in contact with the device and the

10 substrate.

15. An element according to claim 14 wherein the thermal device and a wall of the recess are in direct contact one with the other.

16. An element according to claim 14 or 15 wherein the filler fixes the thermal device in position in the recess.

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17. An element according to any of claims 14, 15, or 16 wherein the filler fills a volume of the recess intermediate the recess wall and the thermal device.

18. An element according any of claims 14 to 17 wherein a wall of the recess has surfaces which flare apart from a line of convergence to an opening or rim of the recess.

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19. An element according to claim 18 wherein the surfaces are slanted such that the wall of the recess wall defines a V-profile.

20. An element according to claim 19 wherein the recess wall includes a substantially U-shaped profile replacing the tip of the V-shaped profile so that the slanted surfaces flare apart from the U-shaped profile opening or rim.

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21. An element according to claim 20 wherein the portion of the recess having the

U-shaped profile opening contains the thermal device.

22. An element according to claim 20 or 21 where an external surface of the thermal device is flush with a plane spanning the U-shaped profile opening, or a plane across the brim of the U-shaped profile opening.

23. An element according to any of claims 14 to 22 wherein the thermal device 5 comprises a hollow tube.

24. An element according to claim 23 comprising a means of suppling the hollow tube with fluid, wherein the means passes through the recess wall or the filler.

25. An element according to any of claims 14 to 22 including wherein the thermal device comprises a wire.

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26. An element according to claim 25 comprising a means of supplying the wire with electrical current, wherein the means passes through the recess wall or the filler.

27. An element according to claim 25 or 26 wherein the wire is sheathed in an electrically insulating sheath.

28. An element according to any of claims 14 to 27 wherein the thermal device 15 comprises a thermally conductive shield.

29. An element according to claim 27 or 28 wherein the sheath comprises a mica weave.

30. An element according to any of claims 14 to 28 wherein the recess is located in a substrate comprising or adjoining a conduit for a thermal working fluid.

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31. A portion of a refrigerator evaporator comprising an element according to any of claims 14 to 30.

32. A portion of an aircraft fuselage skin or aircraft wing skin or aircraft engine nacelle or aircraft fuel system comprising an element according to any of claims 14 to

30.

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33. A thermal heat exchanger comprising a temperature modification element according to any of claims 14 to 30.

34. An exchanger according to claim 33 comprising a first plate comprising the recess.

35. An exchanger according to claim 34 wherein the recess is located adjacent to a conduit for a thermal working fluid, wherein the conduit is in or connected to the plate.

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36. An exchanger according to claim 34 wherein the recess is interspersed with conduit for a thermal working fluid, wherein the conduit is in or connected to the plate.

37. An exchanger according to claim 33 comprising a first plate and a second plate joined face to face, wherein the first plate comprises the recess.

38. An exchanger according to claim 37 where the recess is arranged such that the 10 recess has a rim on the exchanger exterior.

39. An exchanger according to claim 37 wherein the recess is arranged such that the recess has a rim on a face of the second plate that is joined to a face of the first plate.

40. A temperature modification element substantially as described herein with reference to the accompanying drawings.

Intellectual

Property

Office

Application No: Claims searched:

GB1613545.1 1 to 40