Methods and apparatus for introducing air-entrainable material into a channel or recess

Abstract

 A method of introducing insulating material or other air-entrainable material into an open recess or channel e.g. in a panel frame 59, includes applying to said recess or channel a filling head means 54 having a cover plate means 74 associated therewith, thereby temporarily to cover said recess locally to define a local cavity. A blown mixture of air and insulating material or other air-entrainable material is introduced into the cavity from the filling head means whilst leakage of the insulating material or other air-entrainable material is prevented. This is typically achieved by providing an extended cover plate such that the accumulated friction between the air-entrainable material and the cover plate and the walls of the recess is sufficient to prevent or substantially reduce leakage. The recess or channel is caused to move relative to said filling head means 54, progressively to fill said recess or channel.

Description

[0001] This invention relates to methods and apparatus for introducing air-entrainable material such as, for example, insulating material, into an open recess or channel and to products so formed. In particular, but not exclusively, the invention relates to methods and apparatus for introducing insulating fibre material such as fibrous or foam material into an open frame element such as a timber frame.

[0002] Houses may be built using a timber frame construction method in which timber-framed panels are manufactured in a factory and then erected on site. As shown in Figure 1 of the accompanying drawings, a typical panel comprises a timber "studding" framework of elements typically 90 mm x 40 mm with a plywood sheathing board forming the external skin and plasterboard the internal skin. Alternative materials may sometimes be used, and a polythene vapour control layer may be included under the plasterboard. The vertical studding is normally placed at fixed modular distances, for example 600 mm, but as seen in Figure 1, design considerations often result in complex arrangements of the studs, e.g. where a door or window is included. The panels are normally insulated by pressing mineral fibre "quilt" or "batts" between the studding, prior to fixing the plasterboard.

[0003] Use of mineral fibre quilt or batts requires cutting the material to size and fitting in the recesses and this is time consuming and awkward and special precautions may need to be taken with the mineral fibre.

[0004] As an alternative to mineral fibre quilt, it is possible to use a loose-fill insulation of fibres such as mineral fibre or, preferably, cellulose fibre. In this method, the fibres are compressed into the space so as to give a stable fill which will resist settlement over time. Previous methods of insulating panels in this way have included drilling holes in the top or bottom stud of the panel, between each pair of vertical studs, and inserting a lance through the hole through which fibre is blown. The lance is fully inserted and then gradually withdrawn as filling proceeds. Alternatively holes may be drilled in either the plywood or plasterboard skins and then a nozzle can be inserted through the hole through which the fibre is blown.

[0005] There are many disadvantages involved with these methods. The panels are damaged, which is not easy to make good. It is difficult to provide an even fill without localised areas of high density and of low density (which may give rise to settlement of the fibre over time). The complexity of many panels can make the methods difficult or impossible to employ. Since the filling is being done "blind" through a single aperture into each recess, it is not possible to make a visual check to ensure that the filling is complete and uniform.

[0006] We have developed a system for introducing or packing insulating material into the recesses of a timber frame panel, which overcomes or mitigates at least some of the above disadvantages.

[0007] Accordingly, in one aspect of this invention, there is provided a method of introducing insulating material or other air-entrainable material into an open recess or channel, said method including applying to said recess or channel a filling head means having a cover plate means associated therewith, thereby temporarily to cover said recess to define a local cavity, delivering into said cavity a blown mixture of air and insulating material or other air-entrainable material whilst substantially preventing or reducing leakage of the insulating material or other air-entrainable material, and moving said recess or channel relative to said filling head means, progressively to fill said recess or channel.

[0008] The terms "upwards", "downwards", "transversely" etc as used below refer to the various items when the recess or channel extends generally horizontally, and the terms "leading" and "trailing" refer to the direction of relative movement of the filling head and the channel or recess.

[0009] In one arrangement, where said recess or channel is elongate, said method may include effecting relative movement of said filling head means longitudinally along said recess or channel to fill said channel or recess, or a plurality thereof.

[0010] Various filling movements are possible, depending on the shape and configuration of the recesses or channels and the size of the cover plate means. Thus, where a series of elongate channels of generally constant width are to be filled with fibre, the cover plate means and said point of delivery may be moved along each said recess or channel to fill one channel or recess at a time, with the width of the cover plate means being sufficient to extend between opposite sides of said recess or channel.

[0011] Alternatively, in a particularly preferred embodiment for filling a plurality of side by side channels or recesses, a much larger cover plate may be used, long enough to extend between opposite ends of the channels or recesses. Here the cover plate means and the point of delivery may be held stationary whilst the panel is moved beneath them in a single pass so that the channels move transversely in succession under the cover plate.

[0012] The step of substantially preventing or reducing leakage of insulating or other air-entrainable material from said recess or channel may be achieved in a variety of ways. As the cover plate means moves in a given direction relative to a recess or channel, the insulating or other air-entrainable material at the trailing edge of the cover plate (in the sense of said movement direction) will already have been compressed by the delivery of material and this will prevent or reduce leakage from the trailing edge. However, at the leading edge of the cover plate means, where the bulk of the filling has yet to form, it is also necessary to prevent or reduce leakage. In one example, the leakage prevention means comprises an extended leading edge for the cover plate means which is selected with regard to the other operating parameters such as the air velocity, fibre size, filling depth, size and effective friction coefficient of the cover plate means etc, so that the accumulated friction applied both by the leading edge portion of the cover plate means and the opposing base and sides of the recess or channel is sufficient substantially to prevent or reduce leakage of material. The length of the leading edge portion of the plate required for any particular application may easily be determined by one skilled in the art using routine experimentation.

[0013] Alternatively, in one special case, where the filling head is moved longitudinally with respect to the channels or recesses, and it is known that the channels or recesses are of substantially the same width and that there are no obstructions or intermediate timbers above a pre-set height in the channel or recess, the cover plate means may be provided with a downwardly projecting wall for retaining insulating material within said recess or channel.

[0014] Preferably, said cover plate means and said point of delivery are incorporated in an applicator head means, which provides a filling chamber, for example of generally conical or trihedral shape which allows the insulating or other air-entrainable material to flow across the whole width of the channel or recess.

[0015] Preferably, the insulating or other air-entrainable material is agitated prior to or adjacent said delivery point.

[0016] According to another aspect of this invention, there is provided a method of introducing insulating or other air-entrainable material into an open recess or channel which includes margin or wall means, said method including applying across said recess or channel an applicator head means comprising a cover plate means which in use cooperates with said margin or wall means temporarily to enclose said recess channel and, associated with said cover plate means, a downwardly open filling chamber for receiving a blown mixture of air and insulating or other air-entrainable material, said filling chamber extending across a major portion of said cover plate means, to allow said blown mixture to flow across said channel or recess.

[0017] In this way complex patterns of frameworks may be filled with material.

[0018] In a further aspect of this invention there is provided a method of producing an insulated panel, which comprises providing a framework, closing one side of the frame with one or more skin means, thereby to define a generally horizontal array of open recesses separated by respective frame members, using a method as defined above to introduce insulating material into one or more of said recesses, and then securing one or more skin means to the other side of said framework to close said recesses and produce an insulated panel.

[0019] The invention also extends to a panel or other structural element formed in accordance with a method of this invention.

[0020] In yet another aspect of this invention, there is provided apparatus for introducing air-entrainable material into an open recess or channel, said apparatus including a cover plate means for being placed over said recess or channel, a discharge means for discharging a mixture of air and air-entrainable material to one side of said cover plate means, and means for preventing or reducing leakage of said air-entrainable material from said recess or channel in use.

[0021] Preferably, said means for preventing or reducing comprises an extended portion of said cover plate means of length such that the friction accumulated between said extended portion and said material in use is sufficient to prevent or reduce leakage.

[0022] Alternatively, said means for preventing or reducing leakage may comprise a weir or blocking plate means projecting from said one surface of said cover plate means into said recess or channel in use.

[0023] Said discharge means preferably comprises a filling chamber, typically of conical or trihedral form open to said one side of said cover plate means for receiving said mixture and discharging it across at least a substantial portion of the width of the recess or channel.

[0024] Whilst the invention has been described above, it extends to any inventive combination of the features set out above or in the following description.

[0025] The invention may be performed in various ways, and various embodiments thereof will now be described in detail, reference being made to the accompanying drawings, in which:-

Figure 1 is a side elevation of the skeletal framework studding of a typical conventional timber frame panel;

Figure 2 is an underneath plan view of the timber frame panel of Figure 1;

Figure 3 is a schematic top plan view of a first embodiment of filling head in accordance with a further aspect of this invention applied to fill an elongate recess;

Figure 4 is a sectional view through the first embodiment of filling head of this invention illustrated in Figure 3;

Figure 5 is a schematic view illustrating one possible path for filling a timber frame panel of the type shown in Figure 1;

Figure 6 is a transverse section view, on an enlarged scale, of the first embodiment of filling head;

Figure 7 is a section view through a second embodiment of filling head in accordance with the invention, intended for use with panels made up of a series of substantially unobstructed recesses of generally uniform width;

Figure 8 is a view from above of a third embodiment of an extended filling head for filling a timber frame panel in a single uni-directional sweep in a direction transverse to the longitudinal channels of this panel;

Figure 9 is a side view of the arrangement of Figure 8;

Figures 10 and 11 are schematic section and underneath plan views respectively of a first form of agitation mechanism for a filling head of this invention;

Figure 12 is a schematic underneath plan view of an embodiment of agitation mechanism for use with embodiments of extended filling head of the type shown in Figures 8 and 9;

Figure 13 is a schematic transverse section view through a fourth embodiment of an extended filling head for filling a timber frame panel in a single uni-directional sweep in a direction transverse to the longitudinal channels of the panel;

Figure 14 is a schematic plan view of the fourth embodiment of filling head;

Figure 15 is a detailed view of the leading edge of the screeding plate used in Figures 14 and 15;

Figure 16 is a schematic transverse section view of the fourth embodiment of this invention fitted with a finishing roller;

Figure 17 is a schematic transverse section view of the fourth embodiment of this invention fitted with a finishing belt;

Figure 18 is a plan view of a fifth embodiment of this invention fitted with a moveable blanking plate, and

Figures 19(a) to (d) are plan views showing the orientation of the blanking plate with respect to the filling head for a variety of different shapes of panel workpiece.

[0026] Referring initially to Figures 1 and 2, a typical conventional timber frame panel 10 is made up of vertical studding 12 connected at the lower end to a sole plate 14 and at the upper end to a top plate 16. Generally, the spacing between the vertical studding 12 is uniform except where there is an aperture 17 for a door or window. In addition, adjacent vertical studs 12 may be interconnected by a noggin 18. This timber studding framework is sandwiched between an outer plywood sheathing 20 and an inner plasterboard skin 22 to provide a timber frame panel. During production, the internal cavities of the timber frame panel are filled with insulating material either in the form of quilts or batts, or by blowing fibres.

[0027] In the embodiments to be described below, before the final inner (or outer) skin is applied, a travelling applicator head of special design traverses the surface of the panel to blow fibre continuously into a running chamber as the applicator head moves smoothly over the surface.

[0028] Referring now to Figure 3, in its simplest form, the applicator head 24 comprises a generally flat cover plate 26 which is wide enough to fill one channel between two timber studs (typically spaced at 600 mm). In order to fill the channel or recess between the two timber studs, the filling head is advanced in the direction of the arrow A whilst a mixture of air and fibre is blown through the filling chamber 28. As will be seen from Figures 3 and 4, the cover plate has an extended leading edge 30 which effectively closes the leading edge of the cavity into which the fibre is blown under pressure. Because of the direction of movement, the fibre at the trailing edge is already packed to a stable state and therefore the trailing edge can be much shorter. The length of the leading edge is such that there is sufficient friction provided between the surfaces of the underlying sheathing panel 20 and the underside of the leading edge 30 to resist the blowing pressure which might otherwise force fibre out from below the plate 26, thus preventing a complete and well-compressed fill. We have found that this dimension is typically about 5-10 times the depth to be filled.

[0029] The filling chamber 28 may take many forms but in this example takes a hollow conical shape, as seen in figures 4 and 6. This shape effectively spreads the pressure evenly across the width of the channel to be filled, giving a correspondingly even density which cannot be obtained with the earlier drill and fill processes. Additionally, the chamber has the great advantage of allowing complex sections to be filled, where for example intermediate studs 121 are encountered as in the channel or recess identified at 32 on Figure 1. As seen in Figure 6, it can be seen that the chamber allows fibre to flow to each side of the intermediate stud 12¹ whereas, if there were no filling chamber and a simple access hole, the channel to one side of the intermediate stud would not be filled.

[0030] As seen in Figure 5, the filling head is traversed in serpentine fashion along adjacent recesses or channels and filling proceeds over the entire panel, irrespective of the position of additional timbers, whether they be at right angles or parallel to the direction of travel. Any areas designated as windows 17 or doors (i.e. sections not to be filled with insulation) can be fitted with temporary blanking plates over which the filling head 28 may traverse without obstruction, but without the ingress of fibre which continues to be held under pressure within the filling chamber 28.

[0031] Once the filling head 24 has traversed the entire panel, the fibre fill may be visually inspected for completeness of fill, density etc before the inner plasterboard skin 22 is applied to complete the panel.

[0032] Although in this example the panel is initially part-formed with the outer skin and the skeletal framework, it could of course be partly formed with the inner skin and the skeletal framework. It is of course preferred to keep the panel horizontal during the filling process although we do not exclude the possibility of the panel being oriented differently.

[0033] In the above embodiment, the head has a width slightly larger than the typical horizontal spacing of the timber studs 12, and traverses the recesses one by one moving generally longitudinally with respect to each recess.

[0034] Referring now to Figure 7, a second embodiment of filling head 24 is illustrated in which the leading edge of the cover plate is foreshortened and a cavity closing piece or weir 34 projects downwardly from the underside of the cover plate to retain fibre within the channel. This design is intended for the special case where it is known that channels will always be of similar width with no obstructions or intermediate timbers.

[0035] Referring now to the arrangement of Figures 8 and 9, there is shown an alternative fixed filling head 44 which spans the whole side of the timber frame panel and under which a panel sweeps in a single direction relative as shown by the arrow B, to enable the whole panel to be passed at a controlled speed under the head. This arrangement is particularly preferred for semi-automated production of timber frame panels because movement in a single direction only is required, and a wide variety of different designs of the panel can be filled. Here the head 44 includes a cover plate 26, and an elongate filling chamber 48 of generally trihedral cross section as seen more clearly in Figure 9. The filling chamber 48 is supplied with a mixture of air and fibres through the hoses 46. In this arrangement, the head 44 fills the panel one channel at a time but it fills across the channel rather than along its length. The chamber 48 can be of various designs but a trihedron as shown has been found to be effective in providing a good flow and even dispersion without resulting in blockages within the chamber.

[0036] Referring now to Figures 10 and 11, it is found that the above arrangements may be enhanced by using methods which help to "fluidise" the fibre within the filling chamber 28, thus improving the ability of the fibre to flow willingly and easily even into very small cavities. We have devised two methods which may be used either separately or in combination, namely mechanical agitation and air pulsing. In Figures 10 and 11, a mechanical agitator is disposed within the filling chamber 28 or 48 and comprises a blade 50 mounted on a vertical shaft which is rotated within the chamber further to disperse and fluidise the fibres in the airflow. A series of these devices could be used in the embodiment of Figures 8 and 9. Alternatively, the arrangement of Figures 8 and 9 may incorporate a mechanical agitator as shown in Figure 12. Here a horizontal elongate rod 52 is rotatably and axially moveable within the filling chamber 48. The agitator includes a series of paddles 54 at spaced intervals. In use the rod 52 is rotated and reciprocated back and forth to agitate fibre in the chamber.

[0037] The air pulsing may be achieved by suddenly and periodically cutting off the pressure exerted by the blowing machine on the chamber, or by applying a pulse of compressed air to the chamber to make use of the "reverse jet" principle. In the case of the arrangement of Figures 8 and 9, each filling point may be pulsed in turn in order to encourage the fibre to flow back and forth along the length of the chamber.

[0038] Referring now to Figure 13, in this embodiment the filling head 54 is similar to that shown in Figures 8 and 9 and is mounted above a workpiece table 56 having a drive roller 58 for driving an open-topped timber frame panel 59 to be filled. The filling head 54 has a vertical trailing wall 60, a leading wall 62 inclined in this example at about 60° to the trailing wall 60 and a number of fibre feed inlets 64 in the roof 66. It is emphasised that the angles given here are by way of example, relating to one particular implementation, and that different angles may be used. The overall requirement is that the walls should be sufficiently divergent so that the compressed fibre in the filing head does not block and remains free to flow into the panel at all times when the space below is not yet fully filled. In the particular example of Figure 13, it has been much found that angles in excess of 62° may make the head too divergent and adversely alter fibre distribution, and that angles much below about 45° may increase the risk of the head becoming blocked with fibres.

[0039] Adjacent the lower edge of the trailing wall 60 is a screeding plate 68 which is moveably mounted by a cam arrangement 70 which is driven to oscillate the screeding plate 68 in the horizontal plane with the leading edge protruding into the filling head 54. This provides a number of important advantages. It serves to distribute and agitate the air/fibre mix within the filling chamber 54. The plate 68 has a serrated leading edge 72 which serves to cut through the mass of fibres with a bread knife effect. The lower surface of the screeding plate 68 applies a smoothing effect to the fibrous insulating material once it has been delivered into the panel 59. The screeding plate 68 also provides a sealing effect.

[0040] At the leading edge of the filling head is a cover plate 74 which, in conjunction with the fibrous material and the panel framework, retains fibre in the panel and provides a sealing action.

[0041] Referring now to Figures 16 and 17, there are shown two different optional finishing arrangements which may be beneficial depending on the nature of the fibres and the particular intended application. In Figure 16 a scrub roller 76 is driven contrary to the direction of movement of the panel as it is advanced under the filling head 54 to scrub the surface of the insulating material to level it, with suitable vacuum means (not shown) to remove surplus material. Alternatively the roller may be driven in the same sense as the panel to roll the surface.

[0042] In Figure 17, a moving conveyer belt arrangement 78 moves at the same speed as the panel to retain and smooth the surface of the insulating material.

[0043] Referring now to Figures 18 and 19, it is common to encounter wall panels in which the sides are not parallel, for example gable wall sections. In this case it is again possible to use blanking plates to 'square up' the panel, but an alternative is shown in these Figures where a blanking plate 80 fixed under the filling head 54, and in close contact with it, moves in and out as required to ensure that any section of the filling head not directly over the panel will be blanked off to prevent the escape of the insulation. In Figure 18, the movable plate 80 is kept in contact with the non-parallel edge by either springs 82 or pneumatic pressure or other means. The wheels 76 mounted to the plate follow the movement of the non-parallel edge exactly to ensure that the blanking plate is at all times correctly positioned.

[0044] Figures 19 (a) to (d) show how the position of the plate 74 changes with different shapes of panel to allow all types to be passed under the filling head without loss of insulation.

[0045] In addition, the pressure in the feed inlets 62 may be monitored for process control. For example, at commencement of filling of each empty panel section, the pressure drops and the traverse of the panel can be slowed or stopped until pressure increases, indicating that that section is full. Additionally or alternatively, when pressure reaches a pre-set level in any single hose, the air intake to that hose can be partially or wholly shut off in order to prevent excessive pressure in one area, or the pressure across all the filling points in the panel can be balanced continuously to provide a consistent fill.

Claims

1. A method of introducing insulating material or other air-entrainable material into an open recess or channel, said method including applying to said recess or channel a filling head means having a cover plate means associated therewith, thereby temporarily to cover said recess locally to define a local cavity, delivering into said cavity a blown mixture of air and insulating material or other air-entrainable material whilst substantially preventing or reducing leakage of the insulating material or other air-entrainable material, and effecting relative movement of said recess or channel relative to said filling head means, progressively to fill said recess or channel.

2. A method according to Claim 1, wherein said recess or channel is elongate and said filling head means is moved longitudinally with respect to said recess or channel.

3. A method according to Claim 1, for introducing insulating material or other air-entrainable material into a plurality of channels or recesses arranged side by side, wherein said plurality of channels or recesses is moved transversely with respect to said filling head means, and preferably said filling head means remains stationary whilst said plurality of channels or recesses moves with respect thereto.

4. A method according to any preceding Claim, wherein said filling head means includes an extended leading edge (in the sense of the relative movement of the recess or channel) whereby the extended area of contact with insulating or other air-entrainable material in said recess or channel is sufficient to reduce or prevent leakage in that direction.

5. A method according to any of Claims 1 to 3, for filling a recess of substantially constant width and depth, wherein the leading edge of said filling head means includes a downwardly projecting retaining plate means which fits within said recess or channel means.

6. A method according to any of Claims 1 to 4, in which a screeding plate means is moved or oscillated, relative to the filling head means, over the surface of the filled recess or channel to smooth the surface thereof, and to agitate or disturb the insulating material or air-entrainable material within said filling head, and wherein the delivery pressure is advantageously monitored and used to control the speed of relative movement of the filling head means relative to said recess or channel, with the delivery pressure ideally being monitored and used to control the pressure of the air inlet to maintain it below a preset level.

7. A method of producing an insulated timber frame panel which comprises providing an open topped framework panel, filling said panel with insulating material using a method according to any of the preceding Claims, and applying a skin element to finish the panel.

8. Apparatus for delivering insulating material to an open-topped framework panel, said apparatus comprising a filling head means having an inlet for receiving a mixture of air and air-entrainable insulating material, a filling chamber of divergent form, and a cover plate means extending transversely thereof.

9. Apparatus according to Claim 7, wherein said filling chamber has a generally conical inner profile, or wherein said filling head means is elongate, with said filling chamber being polyhedral in transverse cross-section, and said filling head means preferably comprising a trailing wall means extending generally vertically and a leading wall means inclined at an acute angle to said trailing wall means, wherein said leading wall means is advantageously inclined at an angle of between 45° and 65° and preferably about 60°.

10. Apparatus according to Claim 9, wherein said filling head means comprises a plurality of feed inlets disposed along the length of the filling head, with the feed inlets preferably disposed in an upper wall or roof of said filling head, the apparatus conveniently further including means for agitating or disturbing said insulating material within said filling chamber, which may comprise an agitating member movably mounted adjacent the trailing region of said filling chamber and projecting into said chamber, and drive means for moving said agitating member, or alternatively or additionally it may comprise a screeding plate having a leading edge region (which may be serrated) which projects into said filling chamber and defining a lower surface for screeding or projecting the surface of insulating material in said panel.

11. Apparatus according to Claims 10, wherein said drive means includes an eccentric cam arrangement for imparting rotary oscillatory movement to said agitating member.

12. Apparatus according to any of Claims 9 to 11 including workpiece support means for supporting a panel below said filling head means, and traverse means for moving said workpiece support means with respect to said filling head means, and preferably further including means responsive to the delivery pressure to the filling head to control the rate of movement of said traverse means in accordance therewith.

13. Apparatus according to any of Claims 9 to 12, adapted to allow filling of panels whose dimension in the direction parallel to the longitudinal axis of the filling head varies along the length of the panels, which includes a blanking means movably associated with the underside of said filling head, and biassed into engagement with an edge of said panel, whereby the longitudinal dimension of the effective discharge aperture defined by the open end of the filling chamber is varied in accordance with the dimension of the panel.

14. Apparatus according to any of Claims 9 to 13, which includes finishing means disposed aft of the filling head to finish the surface of the insulating material in the panel, the finishing means typically comprising a rotatable roller and/or a moving belt moving in the same sense as said panel.

Drawing