GB2489767A

GB2489767A - Blowing cavity wall insulation out of a wall cavity

Info

Publication number: GB2489767A
Application number: GB1120503.6A
Authority: GB
Inventors: Sam Whitehead
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-11-29
Filing date: 2011-11-29
Publication date: 2012-10-10
Anticipated expiration: 2031-11-29
Also published as: GB2489767B; GB201120503D0

Abstract

A method for removing cavity wall insulation from a cavity wall comprising first and second wall leaves 12, 14 separated by a cavity space, the cavity space 16 being at least partially filled by cavity insulation material 30 comprises the steps of: forming an outlet aperture 54 in a first one of the leaves; injecting compressed air into the cavity at a number of spaced apart locations 42 located above the outlet aperture; and removing at least part of the cavity wall insulation via the outlet aperture 54, wherein the method further comprises the step of forming bands of empty space within the cavity by injecting the compressed air into the cavity via one or more apertures located at different heights, beginning at or towards the base of the wall, and moving upwards in stages.

Description

METHOD AND APPARATUS FOR REMOVING CAVITY WALL INSULATION

Description:

This invention relates to cavity walls, and in particular, to a method and apparatus for the removal of cavity wall insulation.

Most modern brick-built buildings are constructed with cavity walls, that is to say wall structures comprising an inner leaf and an outer leaf separated by an open cavity. The purpose of the cavity is to allow rainwater absorbed by, and transmitted through, the outer leaf of the wall to run down the inner surface of the outer leaf of the wall structure, thereby shielding the inner leaf and keeping it dry.

In recent years, it has become apparent that the thermal performance of buildings can be significantly improved by providing a layer of thermal insulation within the cavity, which inhibits the transmission of convective and radiant heat transmission through the wall structure. In "new builds", it is nowadays commonplace, and in many cases, a legal requirement, for the cavity of a cavity wall structure to be provided with an insulation layer, which usually comprises a rigid sheet of expanded polymeric foam whose thickness is less than the width of the cavity: to maintain an open space within the cavity for the drainage of absorbed rainwater. As such, the cavities in the walls of modern buildings are now much larger than they used to be: to accommodate the rigid insulation layer whilst simultaneously maintaining an open cavity space to protect the inner leaf of the wall structure.

It has also become commonplace, in recent years, for cavity wall insulation to be retrofitted to open cavity wall structures by the injection of insulation material into the cavity. The retrofitting of cavity wall insulation is usually carried out by a process of drilling into the wall to gain access to the cavity at intervals, and injecting particulate insulation material, for example mineral wool or polystyrene beads, to fill the cavity. The process is repeated at intervals over the wall to ensure that the entire cavity is filled with insulation material. A more modern, and alternative approach, is to fill the cavity using a "free-flowing" insulation material, such as polystyrene beads, which can be introduced at the top of the wall structure, and which automatically completely fill the cavity space under the effect of gravity. This approach reduces the number of access holes needed, which reduces the amount of damage inflicted on the building during the installation process. Retrofit cavity wall insulation has become extremely widespread, and is indeed encouraged by many utility companies and government bodies, with the object of improving the thermal performance and efficiency of buildings.

A problem that is becoming increasingly apparent with retrofit cavity wall insulation is the fact that the insulation "bridges" the cavity, providing a pathway for the transmission of moisture and rainwater from the outer leaf to the inner leaf. As such, when the exterior leaf is subjected to rainwater, the rainwater is absorbed by, and is transmitted through, the outer leaf, whereupon it wets the insulation material. In many cases, the writing of the insulation material does not present a serious problem provided the wall structure is exposed to warm and dry conditions from time to time so that the wall and insulation material has time to dry out.

However, where the wall is not exposed to sufficient periods of warm and dry weather, the wall and insulation material may never dry out completely. Over time, this can lead to the insulation material becoming so wet for so long that moisture is eventually transmitted to the inner leaf of the wall structure, where it can cause damp and mould within the interior of the building. This can be detrimental to the health of the occupants of the building, and can seriously degrade the thermal performance of the building.

The obvious solution to this problem, if and/or when it arises, is therefore to remove the cavity wall insulation either completely, or in parts of the building that are affected (for example the facades facing the prevailing weather). However, once retrofit cavity wall insulation has been installed, it is extremely difficult to remove owing to the lack of access to the cavity itself. Moreover, where the insulation material has become very wet, it can mat together or congeal to form a substantially solid mass that cannot be removed, except in large sections.

Hitherto, the only way to remove retrofit cavity wall insulation is to take down parts of the inner, or outer, leaf of the wall to pull the insulation out by hand, and then to re-build the sections of the wall that have been removed. Of course, this approach is extremely destructive, time-consuming, expensive, and has the potential to compromise the structural integrity of the building.

A need therefore arises for a minimally invasive way of removing retrofit cavity wall insulation, and/or of solving one or more of the problems identified above.

According to a first aspect of the invention, there is provided a method for removing cavity wall insulation from a cavity wall comprising first and second wall leaves separated by a cavity space, the cavity space being at least partially filled by cavity insulation material, the method comprising the steps of: forming an outlet aperture in a first one of the leaves; injecting compressed air into the cavity at a point or points located above the outlet aperture; and removing at least part of the cavity wall insulation via the outlet aperture.

The use of compressed air may advantageously help to break-up or fragment the insulation material, and may additionally create a region of positive air pressure within the cavity to expel the fragmented insulation material therefrom, via the outlet aperture in the wall. The invention may therefore enable cavity wall insulation material to be removed from a wall cavity in a minimally invasive or minimally destructive manner, that is to say, without having to remove large sections of one of the wall's leaves.

Preferably, the step of injecting compressed air into the cavity comprises injecting the compressed air into the cavity wall insulation material itself. By doing so, the compressed air can help to blow the cavity wall insulation apart, thereby fragmenting it and enabling it to fall towards the outlet aperture. To do this, an air lance may be used, which can be inserted into the cavity via an aperture extending through the first leaf of the wall. Ideally, and to reduce the amount of damage inflicted on the wall, the aperture (or apertures) through which the air lance is inserted may be the same aperture (or apertures) through which the cavity wall insulation material was originally injected into the cavity.

To facilitate fragmenting the cavity insulation material, the air lance may be manipulated, for example, to sweep discrete jets of air around within the cavity to break-up the insulation material.

As the cavity wall insulation, once fragmented, will tend to fall, the outlet aperture is preferably formed at, or towards, the bottom of the wall.

The method is preferably repeated at different locations on the wall, for example, by injecting compressed air into the cavity at a number of spaced apart locations of the wall. In one preferred embodiment of the invention, compressed air is injected into the cavity sequentially or simultaneously, at a number of horizontally spaced apart locations, which may form a substantially horizontal band of empty space within the cavity below the air injection locations. The method preferably comprises injecting the compressed air into the cavity at a number of spaced apart locations to sequentially form substantially horizontal bands of empty space within the cavity at different heights, beginning at or towards the base of the wall, and moving upwards in stages.

Alternatively, compressed air can be injected into the cavity at a number of vertically spaced apart locations to form a substantially vertical column of empty space within the cavity. The or each vertical column is preferably formed by injecting the compressed air into the cavity at a number of locations at different heights, beginning at or towards the base of the wall, and moving upwards in stages. A number of adjacent or overlapping columns of empty space within the cavity at different horizontal positions can be formed to empty (or partially empty) the cavity of insulation material.

To minimise the damage caused to the interior of the building, and given that the exterior of a building is usually more easily accessible, the first leaf of the wall will normally be the outer leaf of the cavity wall. Conveniently, the second leaf can remain intact.

In order to better manage the collection of waste insulation material, a conduit may be coupled to the outlet aperture to direct the collected insulation material into a waste collection receptacle. The waste insulation material is preferably urged the move along the conduit, for example by injecting a flow of air into the conduit in a desired direction.

A second aspect of the invention provides an air lance suitable for use in the removal of cavity wall insulation from a cavity wall, the air lance comprising a closed-ended tubular body portion into which compressed air can be delivered by way of a coupling, the closed-ended tubular body portion comprising at least one outlet aperture adapted to form, in use, an air jet extending radially outwardly from the body portion.

The outlet aperture or apertures are preferably located at, towards the closed end of the main body portion, which enables the point of action to correspond substantially to the tip of the lance. This helps make the lance easier to use and visualise, given that it will be at least partially concealed from view, when in use.

The air lance may have any number of outlet apertures, although it will be appreaciated that the pressure of each individual air jet will be reduced, for a given input air pressure, as the number of outlet apertures increases. Ideally, the lance comprises single slotted aperture, or a pair of outlet apertures, which may be diametrically opposed, or arranged to create, in use, a fan of jets. As such, the outlet apertures may be located at different circumferential positions to form a substantially directional fan of air jets extending, in use, radially outwardly from the main body portion.

An indicator, such as an arrow, pointer or marker, is preferably provided on the main body portion of the lance to indicate the direction of the jets, which may not be readily apparent to an operator once the lance has been inserted into the wall cavity.

As previously stated, the air lance can preferably be inserted through pre-existing holes in the wall, and so preferably has an outer diameter of between 15 and 50 mm, more preferably an outer diameter of between 20 and 50 mm and most preferably, an outer diameter of substantially mm.

The air lance will ideally be readily connectable to an air hose or air compressor, and so may be provided with a bayonet-type connector. A seal may also be provided, which is adapted to seat, in use, against a portion of a connector of an air hose.

A third aspect of the invention provides a duct suitable for fitting to an outlet aperture in a cavity wall, in particular when removing cavity wall insulation material therefrom, the duct comprising a main body portion comprising a first tubular portion at least partially receivable, in use, in the outlet aperture, a spigot portion extending, in use, outwardly from the wall and communicating with the first tubular portion, and a flange interposed between the first tubular portion and the spigot portion, the flange providing, in use, an abutment surface for limiting the extent of insertion of the first tubular portion into the outlet aperture.

The duct advantageously enables the outflow of waste insulation material to be controlled, that is to say, directed into waste collection bags or a tube leading to a receptacle, such as a skip of the cargo bay of a vehicle for subsequent removal.

Seal means may be provided, for example, on the abutment surface of the flange, to inhibit the accidental or unwanted escape of waste material onto the gorund. By providing a seal between the flange and wall, waste insulation material is substantially constrained to move through the duct to the waste collection device, rather than spilling out through any gaps between the duct and the wall. The seal, where provided, is preferably resiliently deformable, for example, by being manufactured of a resiliently deformable material (such as expanded elastomeric foam) or a fluid-or gas-filled sac.

The duct may further comprise clip means for retaining the first tubular portion at least partially within the outlet aperture of the wall. The clip means is preferably biasable into engagement with an interior surface of the wall, that is, a surface of the wall opposite, in use, to the flange.

The provision of clip means may advantageously enable the duct to be installed and left unattended without fear of it becoming disconnected from the wall and spilling the waste insulation material onto the floor. Any form of clip means may be provided for this purpose, such as an over-centred cam-type spring (such as is commonly provided for retaining recessed light fittings in plenum ceilings). However, given that the duct is likely to be subjected to considerably knocking, outward air pressure etc., a more durable, and more easily repairable, solution may be called for.

An example of such a clip means comprises one or more hooks, the free ends of which are engagable with the surface of the wall opposite the flange. The hooks may be moveably connected to the duct for axial rotation and longitudinal sliding relative thereto, and may be biased, in use, into engagement with wall, by a tension spring or elasticated cord. The spring or elasticated cord, where provided, may be selectively detachable from the duct for releasing the tension therein.

A duct has a spigot portion, which may additionally comprise a flange or engagement means for retaining a collection bag or conduit, an open end of the collection bag or conduit being clampable, in use, between the flange or engagement means and a retainer. The retainer may be an elasticated band locatable, in use, around the spigot portion of the duct.

In order to work effectively, the outer shape and dimensions of the tubular portion preferably correspond substantially to the interior shape and dimensions of the outlet aperture of the wall. As such, outer dimensions corresponding substantially to integer multiples of common brick dimensions may be adopted.

A fourth aspect of the invention provides a collection conduit suitable for collecting insulation material removed from a cavity wall via a duct affixed to an outlet of the wall, the collection conduit comprising an open end sealingly affixable to an outlet spigot of the duct and comprising a side inlet port tube, the side inlet port tube being connectable, in use, to an air blower and being arranged at an angle with respect to a longitudinal axis of the collection conduit.

The collection conduit advantageously enables relatively large volumes of waste insulation material to be removed from the cavity without an operator having to stop periodically to change the collection bags, when they become full. The use of a collection conduit therefore enables the method to be carried out more or less continuously.

The side inlet port tube is preferably detachably affixable to the air blower, which is useful where the conduit itself may be a disposable item. The collection conduit may comprise a generally Y-shaped connector having three openings, the upstream openings being connectable, in use, to the outlet spigot of the duct and the outlet of the air blower, and the downstream opening being connectable, in use, to a tubular outlet conduit portion.

A fifth aspect of the invention provides method described herein carried out using an air lance as also described herein.

A sixth aspect of the invention provides method described herein carried out using a duct as also described herein.

A seventh aspect of the invention provides method described herein carried out using a collection conduit as also described herein.

An eighth aspect of the invention provides a kit of parts for carrying out the method of the invention, the kit comprising an air lance as described herein and an air compressor. The kit of parts may additionally comprise any one or more of the group comprising: a duct according to any of claims 28 to 40; a collection conduit according to any of claims 41 to 43; and an air blower.

Preferred embodiments of the invention shall now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic, partial cross-sectional view through a cavity wall with retrofit cavity wall insulation; Figure 2 is a schematic, partial cross-sectional view through the cavity wall of Figure 1 to which the invention is applied; Figure 3 is a schematic perspective view of an air lance in accordance with an aspect of the invention; Figures 4 to 7 illustrate a sequence of steps for carrying out the method of the invention; Figure 8 is a perspective view of a duct suitable for fitting to the outlet aperture in a wall; Figure 9 is a partial longitudinal section of Figure 8; and Figure 10 is a schematic of a complete kit of parts for carrying out the invention.

In Figure 1, a cavity wall 10 has an inner leaf 12 and an outer leaf 14 separated by a cavity 16. The inner 12 outer leaves 14 of the waIl 10 are supported on foundations 18, which lie below ground level 20. Each leaf 12, 14 comprises a lower portion 22 that sits on foundations 18 and an upper portion 24 commencing above ground level 20. Interposed between the lower 22 and the upper 24 portions of the wall 10, there is provided an inclined Damp Proof Course ("DPC") membrane 26, whose purpose is to prevent moisture from being transmitted upwardly from the ground into the wall structure above by capillary action, and to direct falling water within the cavity space 16 outwardly towards the outer leaf 14 were the shed water can leave the cavity space 16 via bleed holes 28 located beneath the bricks immediately above the DPC layer 26. The cavity space 16 of the wall 10 has been filled with a retrofit cavity wall insulation material 30.

In use, driven rainwater 32 hits the outer leaf 14 where the majority of it runs down the exterior surface of the wall 10. However, some of the rainwater 32 is absorbed by, and transmitted through, the outer leaf 14 of the wall 10, before running down the interior surface of the outer leaf 14 until it meets the DPC layer 26, whereupon it is shed back out through the wall 14 via the bleed holes 28. As such, the inner leaf 12 of the wall 10 is kept dry.

Nevertheless, a proportion of the rainwater 32 penetrating the outer leaf 14 of the wall 10 can be absorbed by the cavity wall insulation material 30. In most cases, the cavity wall insulation material 30 is hydrophobic, that is to say, it repels water and/or resists its absorption, or is given sufficient time to dry out between periods of being wet. However, where a large proportion of rainwater 32 penetrates the outer leaf 14 of the wall 10, for example on a wall facing persistent inclement weather, or where the cavity wall insulation material 30 is unable to dry out, it can nevertheless become wet. If the cavity wall insulation material 30 becomes sufficiently wet, the rainwater 32 can eventually penetrate through from the outer leaf 14 to wet the inner leaf 12 via the "bridge" created by the cavity wall insulation material 30. This can lead to damp and mould formation on or in the inner leaf 12 of waIl 10. Moreover, when the cavity wall insulation material 30 becomes sufficiently wet, it can become sodden and congeal the form a solid mass, which no longer "free flows" to enable it to be removed easily. In such a situation, the only way to remove the cavity wall insulation material is to take down a part of the outer leaf 14 of the wall 10 and to pull the mass of insulation material 30 out before rebuilding the outer leaf 14 again.

In Figure 2, an apparatus in accordance with the invention is shown, which comprises an air lance 40 that can be inserted into the cavity space 16 via an access aperture 42 drilled through the outer leaf 14 of the wall 10. Conveniently, the air lance 40 can be inserted through the relatively small holes (approximately 25 to 30 mm diameter) through which the cavity wall insulation material was originally introduced into the cavity space 16. As such, the insertion of the air lance 40 is "minimally invasive" because it can be inserted into the pre-existing holes 42 already present in the wall 10, simply by removing the "plug" that was used to close those holes 42. The pre-existing holes 42 are usually located in a grid-like fashion over the area of the wall 10 and are often spaced apart in a horizontal and vertical rows at approximately 1 to 2m centres.

The air lance 40, as shown in Figure 3, comprises an elongate closed-ended tube 44 having a bayonet-type fitting 46 at one end to which the end of an air hose 48 can be coupled using a known type of connector 50. The air hose 48 is connected to a high pressure air compressor 51, which operates typically at 250 psi and which provides a high volumetric throughput of compressed air to the lance 40. At the free end of the lance 40 there is provided one or more outlet apertures 52 to enable the compressed air to be blown as jets 53 into the cavity space 16 of the wall 10.

It will also be noted from Figure 2, that an outlet aperture 54 for removing the cavity wall insulation material 30 has been provided towards the bottom of the outer leaf 14 of the wall 10. The outlet aperture 54 is formed by removing a number of bricks to create a generally rectangular opening in the outer leaf 14 of the wall 10 thereby providing access to the cavity space 16. It will be noted that the outlet aperture 54 is located slightly above the DPC membrane 26, but at a location below the lowermost row of apertures 42.

As shown in the sequence of Figures 4 to 7, the method of the invention is carried out as follows: In Figure 4 it will be seen that the air lance 40 has been inserted through a pre-existing aperture 42 in the outer leaf 14 the wall 10 and has been driven into the bulk of the cavity wall insulation material 30. The air supply to the lance 40 is then switched on and compressed air is injected into the cavity wall insulation material 30 at high pressure via the lance's outlet apertures 52. The lance 40 can then be rotated about its longitudinal axis by an operator (not shown) such that the direction of the compressed air jets 53 formed by the outlet apertures 52 sweep" around within the cavity wall insulation material 30 thereby fragmenting it.

As shown in Figure 5, the cavity wall insulation material 30 is thus broken up into small chunks or particles, which fall under the effect of gravity towards the outlet aperture 54 let into the external leaf 14 of the wall 10. A certain amount of the cavity wall insulation material 30 will naturally fall out through the outlet aperture 54 under the effect of gravity and its momentum, although the process of "ejection" of the cavity insulation material 30 will also be assisted by a region of relatively high pressure air 57 created within the cavity space 16 by the air lance 40. As such, the air lance 40 serves to break-up the cavity wall insulation and to force it out through the outlet aperture 54, where it can be collected for disposal.

As shown in Figure 6, eventually, the cavity wall insulation material 30 surrounding the air lance 40 will have fallen away and the high-pressure air jets 53 created by the lance's apertures 52 will have insufficient force to fragment a further cavity wall insulation material. This will become apparent by a visible reduction in the amount of cavity wall insulation material 30 exiting via the outlet aperture 54. At this stage, the air supply can be switched off and the air lance 40 moved to a different location on the wall 10.

Ideally, the method of removing cavity wall insulation material 30 is carried out in a methodical manner, that is to say the air lance 40 is inserted at various points 42 in a horizontal rows along the wall to clear a horizontally extending portion of the cavity wall insulation material 30 below that horizontal row. The advantage of this is that it creates an open space within the wall cavity 16 into which further cavity wall insulation material is free to fall from above during subsequent stages of the removal process.

Once a "horizontal band" of cavity wall insulation material 30 has been removed from the wall cavity 16 towards the bottom of the wall 10, the operator can then open up the apertures 42 at a level above where he or she has been working previously. This is shown in Figure 7.

The process can then be repeated, that is to say the air lance 40 inserted as a point 42 above the lower periphery 56 of the remaining cavity wall insulation material and the compressed air supply 51 switched back on.

By following a methodical approach and by working in horizontal "bands" moving up the wall 10, an operator can ensure that there is always a free space within the cavity space 16 below the lower periphery 56 of the remaining cavity wall insulation material 30, to enable it to fall freely under gravity towards the outlet aperture 54 where it can be removed.

It will be appreciated that a relatively large volume of cavity wall insulation material 30 can exist within the walls of the building. The wall cavities of a typical three-bedroom semi-detached house, for example, may contain up to 10 m3 of compacted cavity wall insulation material 30, which will need to be collected and disposed of efficiently. However, it will be appreciated that the fragmented cavity wall insulation material 30 removed from the cavity will occupy a much greater volume than the compressed cavity wall insulation material 30 present within the cavity itself. This creates a particular problem given that the removed cavity wall insulation material 30 will need to be collected and disposed of, and the site properly cleaned-up before the operators can leave. A need therefore exists for an efficient way of collecting the removed cavity wall insulation material 30. Such a solution is shown in Figures 8, 9 and 10.

In Figures 8 and 9 there is shown, in perspective and in cross-section, respectively, a duct 60 suitable for fitting to the access aperture 54 previously described. The duct 60 comprises a hollow, box-section tube portion 62, one end of which is insertable into the outlet aperture 54 of the wall 10. The tube portion 62 provides a conduit for the fragmented cavity wall insulation material 30 to pass through.

Surrounding the tube portion 62, there is provided a planar flange portion 64, which provides an abutment surface, which prevents the tube portion 62 from being inserted into the wall too far. Ideally, the distance between the end 66 of the tube portion and the flange 64 corresponds to the thickness of the outer leaf 14 of the waIl 10.

Given that the external dimensions of the tube portion 62 will rarely match, exactly, the inner dimensions of the outlet aperture 54, a compressible seal 68 is provided on the abutment surface of the flange portion 64, which surrounds the tube portion 62 and enables a compression seal to be formed between the flange 64 and the exterior surface of the wall. The seal 68 can be manufactured of a compressible foam material, such as expanded silicone foam, or can be formed as a hollow, inflatable seal.

To retain the duct 60 against the wall 10, a pair of spring-loaded clips 70 is provided. The clips comprise hooked end portions 72 that can be rotated about their longitudinal axes to face outwardly so as to engage with the inner surface of the outer leaf 14 of the wall, or rotated to face inwardly to clear the periphery of the aperture 54, as required. The hooked end portions 72 are mounted to the interior of the tube portion 62 of the duct 60 to rotate about their longitudinal axes by way of saddle clamps 74. The hooked end portions 72 of the clips 70 also comprise an eyelet 76 to which a length of bungee cord or a spring can be affixed, which urges the hooked end portions 72 towards the end 66 of the tube portion, thereby exerting, in use, a compressive force to seat the flange portion 64 of the duct 60, or the seal 68, against the exterior surface of the wall 10.

The bungee cords or springs 78 can be tensioned by an operator pulling on them and securing them to the other end of the duct 62, i.e. at a location that is accessible externally. In the illustrated embodiment, the free ends of the bungee cords 78 are provided with hooks 80 that simply hook over the opposite free end 82 of the tube portion 62 of the duct 60.

As mentioned previously, the tubular portion 62 of the duct 60 extends outwardly from the wall and provides a convenient spigot to which a collection tube or rubbish bag can be affixed for collecting the removed insulation material 30. As can be seen in Figures 8 and 9, the external free end 82 of the tube portion 62 comprises an outwardly directed flange portion, which provides an abutment surface for a bungee cord 84, which can be stretched around the tube portion 62 to grip the end of a collection bag or tube 86.

Where collection bags are used, these can be relatively easily attached to, and detached from, the end 82 of the tube portion 62 of the duct 60 by releasing the bungee cord 84. The collected insulation material 30 can thus be bagged up at intervals, that is to say, each time a collection bag has been filled. This solution may be satisfactory in many cases.

Where a large amount of insulation material 30 is to be collected, or where the operator wants to work continuously, a collection tube 88, as shown in Figure 10, can be fitted to the "spigot" of the duct 60. In this case, the collected insulation material 30 flows from the cavity space 16, via the outlet aperture 54, along the tube 88 and into a suitable receptacle 90, such as a skip or the cargo compartment of a vehicle. Where the tube 88 is relatively long, or where the receptacle 90 is located "uphill" of the outlet aperture 54, a blown conveyance system is conveniently provided.

A blown conveyance system, such as that shown in Figure 10, comprises an air blower 92 that is affixed to a V-shaped side inlet 94 of the collection tube 88. The air blower 92 comprises a high speed fan that blows air into the collection tube in the intended direction of travel, as indicated by arrows 96. This arrangement creates a vacuum in a region 98 upstream of the V-shaped inlet 94, which sucks the collected insulation material 30 from the duct 60, along the tube 88, and into the receptacle 90. This process is, of course, assisted by the relatively high pressure region 57 within the wall cavity space 16, as previously described. The air blower 92 can, of course, be fitted to the V-shaped side inlet 94 using similar bungee-cord type connectors as described previously, and a separate V-shaped junction piece may be provided to which three tubes can be fitted to connect to the outlet of the duct 60, the air blower 92 and to the receptacle 90, as described above.

One aspect of the invention see a kit of parts for carrying out the method of the invention comprising an air lance 40 and instructions directing the method as described above. Additionally, the kit may also include any one of more of the duct 60, waste collection bags, a waste collection tube, a Y-shaped side inlet 94, an air blower, an air compressor and so on.

The invention is not restricted to the details of the foregoing embodiments, which are merely exemplary of the invention. For example, the shape, configuration and materials of the various parts of the invention could be changed without departing from the scope of the invention.

Claims

Claims: 1. A method for removing cavity wall insulation from a cavity wall comprising first and second wall leaves separated by a cavity space, the cavity space being at least partially filled by cavity insulation material, the method comprising the steps of: forming an outlet aperture in a first one of the leaves; injecting compressed air into the cavity at a point or points located above the outlet aperture; and removing at least part of the cavity wall insulation via the outlet aperture.
2. A method as claimed in claim 1, wherein the step of injecting compressed air into the cavity comprises injecting the compressed air into the cavity wall insulation material.
3. A method as claimed in claim 1 or claim 2, wherein the compressed air is injected into the cavity or insulation using an air lance.
4. A method as claimed in claim 3, wherein the air lance is inserted through an aperture extending through the first leaf into the cavity.
5. A method as claimed in claim 4, wherein the aperture is the same aperture through which the cavity wall insulation material was originally injected into the cavity.
6. A method as claimed in any of claims 3, 4 or 5, further comprising the step of fragmenting the cavity insulation material by manipulation of the air lance to movably direct discrete jets of air within the cavity to break-up the insulation material.
7. A method as claimed in any preceding claim, wherein the outlet aperture is formed at, or towards, the bottom of the first leaf.
8. A method as claimed in any preceding claim, wherein the step of injecting compressed air into the cavity comprises injecting compressed air into the cavity at a number of spaced apart locations of the first leaf.
9. A method as claimed in claim 8, wherein the step of injecting the compressed air into the cavity at a number of spaced apart locations comprises injecting the air sequentially at a series of substantially horizontal positions to form a substantially horizontal band of empty space within the cavity.
10. A method as claimed in claim 9, wherein the step of injecting the compressed air into the cavity at a number of spaced apart locations comprises sequentially forming substantially horizontal bands of empty space within the cavity at different heights, beginning at or towards the base of the wall, and moving upwards in stages.
11. A method as claimed in claim 8, wherein the step of injecting the compressed air into the cavity at a number of spaced apart locations comprises injecting the air sequentially at a number of vertically spaced apart locations to form a substantially vertical column of empty space within the cavity.
12. A method as claimed in claim 11, wherein the vertical column is formed by injecting the compressed air into the cavity at a number of locations a different heights, beginning at or towards the base of the wall, and moving upwards in stages.
13. A method as claimed in claim 12, wherein the step of injecting the compressed air into the cavity at a number of spaced apart locations comprises forming a number of adjacent or overlapping columns of empty space within the cavity at different horizontal positions.
14. A method as claimed in any preceding claim, wherein the first leaf of the wall is the outer leaf of the cavity wall.
15. A method as claimed in any preceding claim, further comprising the step of providing a conduit coupled to the outlet aperture to direct the collected insulation material into a waste collection receptacle.
16. A method as claimed in claim 15, further comprising the step of urging the collected insulation material along the conduit.
17. A method as claimed in claim 16, wherein the step of urging the collected insulation material along the conduit comprises injecting a flow of air into the conduit in a desired direction.
18. An air lance suitable for use in the removal of cavity wall insulation from a cavity wall, the air lance comprising a closed-ended tubular body portion into which compressed air can be delivered by way of a coupling, the closed-ended tubular body portion comprising at least one outlet aperture adapted to form, in use, an air jet extending radially outwardly from the body portion.
19. An air lance as claimed in claim 18, wherein the outlet aperture or apertures are located at, towards the closed end of the main body portion.
20. An air lance as claimed in claim 19, comprising a pair of outlet apertures.
21. An air lance as claimed in claim 20, wherein the outlet apertures are diametrically opposite one another.
22. An air lance as claimed in claim 20, wherein the outlet apertures are located at different circumferential positions to form a substantially directional fan of air jets extending, in use, radially outwardly from the main body portion.
23. An air lance as claimed in any of claims 18 to 22, wherein the tubular body portion has an outer diameter of between 15 and 50 mm.
24. An air lance as claimed in any of claims 18 to 23, wherein the tubular body portion has an outer diameter of between 20 and 50 mm.
25. An air lance as claimed in any of claims 18 to 24, wherein the tubular body portion has an outer diameter of substantially 25 mm.
26. An air lance as claimed in any of claims 18 to 25, wherein the coupling comprises a bayonet-type connector.
27. An air lance as claimed in claim 26, wherein the coupling comprises a seal adapted, in use, to seat against a portion of a connector of an air hose.
28. A duct suitable for fitting to an outlet aperture in a cavity wall, in particular when removing cavity wall insulation material therefrom, the duct comprising a main body portion comprising a first tubular portion at least partially receivable, in use, in the outlet aperture, a spigot portion extending, in use, outwardly from the wall and communicating with the first tubular portion, and a flange interposed between the first tubular portion and the spigot portion, the flange providing, in use, an abutment surface for limiting the extent of insertion of the first tubular portion into the outlet aperture.
29. A duct as claimed in claim 28, further comprising seal means affixable to the abutment surface of the flange.
30. A duct as claimed in claim 29, wherein the seal means is resiliently deformable.
31. A duct as claimed in claim 29 or claim 30, wherein the seal means is manufactured of a resiliently deformable material such as expanded elastomeric foam or a gas-filled sac.
32. A duct as claimed in any of claims 28 to 31, further comprising clip means for retaining the first tubular portion at least partially within the outlet aperture of the wall.
33. A duct as claimed in claim 32, wherein the clip means is biasable into engagement with an interior surface of the wall, that is, a surface of the wall opposite, in use, to the flange.
34. A duct as claimed in claim 32 or claim 33, wherein the clip means comprises one or more hooks, the free ends of which are engagable with the surface of the wall opposite the flange.
35. A duct as claimed in claim 34, wherein the hooks are moveably connected to the duct for axial rotation and longitudinal sliding relative thereto.
36. A duct as claimed in claim 34 or claim 35, wherein the hooks are biased, in use, into engagement with wall, by a tension spring or elasticated cord.
37. A duct as claimed in claim 36, wherein the spring or elasticated cord is selectively detachable from the duct for releasing the tension therein.
38. A duct as claimed in any of claims 28 to 37, wherein the spigot portion of the duct comprises a flange or engagement means for retaining a collection bag or conduit, an open end of the collection bag or conduit being clampable, in use, between the flange or engagement means and a retainer.
39. A duct as claimed in claim 38, wherein the retainer comprises an elasticated band locatable, in use, around the spigot portion of the duct.
40. A duct as claimed in any of claims 28 to 39, wherein the outer shape and dimensions of the tubular portion correspond substantially to the interior shape and dimensions of the outlet aperture of the wall.
41. A collection conduit suitable for collecting insulation material removed from a cavity wall via a duct affixed to an outlet of the wall, the collection conduit comprising an open end sealingly affixable to an outlet spigot of the duct and comprising a side inlet port tube, the side inlet port tube being connectable, in use, to an air blower and being arranged at an angle with respect to a longitudinal axis of the collection conduit.
42. A collection conduit as claimed in claim 41, wherein the side inlet port tube is detachably affixable to the air blower.
43. A collection conduit as claimed in claim 41 or claim 42 comprising a V-shaped connector having three openings, the upstream openings being connectable, in use, to the outlet spigot of the duct and the outlet of the air blower, and the downstream opening being connectable, in use, to a tubular outlet conduit portion.
44. A method as claimed in any of claims 1 to 17 carried out using an air lance according to any of claims 18 to 27.
45. A method as claimed in any of claims 1 to 17 carried out using a duct according to any of claims 28 to 40.
46. A method as claimed in any of claims 1 to 17 carried out using a collection conduit according to any of claims 41 to 43.
47. A kit of parts for carrying out the method of claims 1 to 17 comprising an air lance according to any of claims 18 to 27 and an air compressor.
48. A kit of parts as claimed in claim 47, further comprising any one or more of the group comprising: a duct according to any of claims 28 to 40; a collection conduit according to any of claims 41 to 43; and an air blower.
49. A method, air lance, duct, or outlet conduit substantially as hereinbefore described, with reference to, and as illustrated in, Figures 2 to 10 of the accompanying drawings.AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWSClaims: 1. A method for removing cavity wall insulation from a cavity wall comprising first and second wall leaves separated by a cavity space, the cavity space being at least partially filled by cavity insulation material, the method comprising the steps of: forming an outlet aperture in a first one of the leaves; injecting compressed air into the cavity at a number of spaced apart locations located above the outlet aperture; and removing at least part of the cavity wall insulation via the outlet aperture, wherein the method further comprises the step of forming bands of empty space within the cavity by injecting the compressed air into the cavity via one or more apertures located at different heights, beginning at or towards the base of the wall, and moving upwards in stages.C"4t' 2. A method as claimed in claim 1, wherein the step of injecting compressed air into the cavity comprises injecting the compressed air into the cavity wall insulation material.3. A method as claimed in claim 1 or claim 2 wherein the compressed air is injected into the cavity or insulation using an air lance.4. A method as claimed in claim 3, wherein the air lance is inserted through an aperture extending through the first leaf into the cavity.5. A method as claimed in claim 4, wherein the aperture is the same aperture through which the cavity wall insulation material was originally injected into the cavity.6. A method as claimed in any of claims 3, 4 or 5, further comprising the step of fragmenting the cavity insulation material by manipulation of the air lance to movably direct discrete jets of air within the cavity to break-up the insulation material.7. A method as claimed in any preceding claim, wherein the outlet aperture is formed at, or towards, the bottom of the first leaf.8. A method as claimed in any preceding claim, wherein the step of injecting the compressed air into the cavity at a number of spaced apart locations comprises injecting the air sequentially at a series of substantially horizontal positions to form a substantially horizontal band of empty space within the cavity.9. A method as claimed in any preceding claim, wherein the step of injecting the compressed air into the cavity at a number of spaced apart locations comprises injecting the air sequentially at a number of vertically spaced apart locations to form a substantially vertical column of empty space within the cavity.10. A method as claimed in claim 9, wherein the vertical column is formed by injecting the r compressed air into the cavity at a number of locations a different heights, beginning at or 0 towards the base of the wall, and moving upwards in stages. r11. A method as claimed in claim 10, wherein the step of injecting the compressed air into the cavity at a number of spaced apart locations comprises forming a number of adjacent or overlapping columns of empty space within the cavity at different horizontal positions.12. A method as claimed in any preceding claim, wherein the first leaf of the wall is the outer leaf of the cavity wall.13. A method as claimed in any preceding claim, further comprising the step of providing a conduit coupled to the outlet aperture to direct the collected insulation material into a waste collection receptacle.14. A method as claimed in claim 13, further comprising the step of urging the collected insulation material along the conduit.15. A method as claimed in claim 14, wherein the step of urging the collected insulation material along the conduit comprises injecting a flow of air into the conduit in a desired direction.16. A method as claimed in any of claims 3 to 15, wherein the air lance comprises a closed-ended tubular body portion into which compressed air can be delivered by way of a coupling, the closed-ended tubular body portion comprising at least one outlet aperture adapted to form, in use, an air jet extending radially outwardly from the body portion.17. A method as claimed in claim 16, wherein the outlet aperture or apertures of the lance are located at, towards the closed end of the main body portion.18. A method as claimed in claim 17, comprising the step of blowing the compressed air through a pair of outlet apertures of the lance. c\J19. A method as claimed in claim 18, wherein the outlet apertures are diametrically opposite LI) one another.20. A method as claimed in claim 18, wherein the outlet apertures of the lance are located at c\J different circumferential positions to form a substantially directional fan of air jets extending, in use, radially outwardly from the main body portion.21. A method as claimed in any of claims l6to 20, wherein the tubular body portion of the lance has an outer diameter of between 15 and 50 mm.22. A method as claimed in any of claims 16 to 21, wherein the tubular body portion of the lance has an outer diameter of between 20 and 50 mm.23. A method as claimed in any of claims l6to 22, wherein the tubular body portion of the lance has an outer diameter of substantially 25 mm.24. A method as claimed in any of claims l6to 23, wherein the lance's coupling comprises a bayonet-type connector.25. A method as claimed in claim 24, wherein the coupling comprises a seal adapted, in use, to seat against a portion of a connector of an air hose.26. A method according to any of claims 13 to 25, wherein the conduit comprises a main body portion comprising a first tubular portion at least partially receivable, in use, in the outlet aperture, a spigot portion extending, in use, outwardly from the wall and communicating with the first tubular portion, and a flange interposed between the first tubular portion and the spigot portion, the flange providing, in use, an abutment surface for limiting the extent of insertion of the first tubular portion into the outlet aperture.27. A method as claimed in claim 26, further comprising seal means affixable to the abutment r LI) surface of the flange.28. A method as claimed in claim 27, wherein the seal means is resiliently deformable. r c\J29. A method as claimed in claim 27 or claim 28, wherein the seal means is manufactured of a resiliently deformable material such as expanded elastomeric foam or a gas-filled sac.30. A method as claimed in any of claims 26 to 29, further comprising clip means for retaining the first tubular portion at least partially within the outlet aperture of the wall.31. A method as claimed in claim 30, wherein the clip means is biasable into engagement with an interior surface of the wall, that is, a surface of the wall opposite, in use, to the flange.32. A method as claimed in claim 30 or claim 31, wherein the clip means comprises one or more hooks, the free ends of which are engagable with the surface of the wall opposite the flange.33. A method as claimed in claim 32, wherein the hooks are moveably connected to the duct for axial rotation and longitudinal sliding relative thereto.34. A method as claimed in claim 32 or claim 33, wherein the hooks are biased, in use, into engagement with wall, by a tension spring or elasticated cord.35. A method as claimed in claim 34, wherein the spring or elasticated cord is selectively detachable from the duct for releasing the tension therein.36. A method as claimed in any of claims 26 to 35, wherein the spigot portion of the duct comprises a flange or engagement means for retaining a collection bag or conduit, an open end of the collection bag or conduit being clampable, in use, between the flange or engagement means and a retainer. c\J37. A method as claimed in claim 36, wherein the retainer comprises an elasticated band LI) locatable, in use, around the spigot portion of the duct.38. A method as claimed in any of claims 26 to 37, wherein the outer shape and dimensions of c\J the tubular portion correspond substantially to the interior shape and dimensions of the outlet aperture of the wall.39. A method according to any preceding claim, wherein the step of removing the cavity wall insulation comprises directing it through a collection conduit, the collection conduit comprising an open end sealingly affixable to an outlet spigot of the duct and comprising a side inlet port tube, the side inlet port tube being connectable, in use, to an air blower and being arranged at an angle with respect to a longitudinal axis of the collection conduit.40. A method as claimed in claim 40, wherein the side inlet port tube is detachably affixable to the air blower.41. A method as claimed in claim 39 or claim 40 wherein the collection conduit comprises a Y-shaped connector having three openings, the upstream openings being connectable, in use, to the outlet spigot of the duct and the outlet of the air blower, and the downstream opening being connectable, in use, to a tubular outlet conduit portion.42. A method substantially as hereinbefore described, with reference to, and as illustrated in, Figures 2 to 10 of the accompanying drawings. c\J rLU r c\J