AU604247B2

AU604247B2 - Insulation production

Info

Publication number: AU604247B2
Application number: AU75746/87A
Authority: AU
Inventors: Richard Laurance Lewellin
Original assignee: Australian Cellulose Industries Pty Ltd
Current assignee: Australian Cellulose Industries Pty Ltd
Priority date: 1986-07-18
Filing date: 1987-07-16
Publication date: 1990-12-13
Anticipated expiration: 2007-07-16
Also published as: AU7574687A

Description

AUSTRAL IA PATENTS ACT COMPLETE SPECIFICATION ii4' I7 1

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ORIGINAL

(FOR OFFICE USE) Class Int Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art: r, t t .U e Name of Applicant(s): AUS.TRALIAN .CELLULOSE INDUSTRIES PTY. LTD,.

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Address of Applicant(s): 6 Gr.r.mw.ade. Cres.cent, Frankston, Victoria, 3199 o, Actual Inventor(s) R.ICHARD LAURANCE LEWELL IN..

Address for Service: PATENT ATTORNEY SERVICES, 1025 Whitehorse Road, Box Hill, Victoria 3128 Complete specification for the invention entitled: INSULATION PRODUCTION The following statement is a full description of this invention, including the best method of performing it known to us INSULATION PRODUCTION This invention relates to production of insulation having fibrous material ingredients and particularly insulation having a volume of air space within the insulation to utilize the insulating properties of quiescent air.

It has been proposed to produce a fibrous insulation batt by ragging, teasing or otherwise doffering a fibrous feed material to form a fibre sliver. This sliver is passed then to a lapper which reciprocates the fibre silver so as to build up a o mat of a desired thickness. The mat is sprayed with a binding iO: substance such as a resin and the binding substance is cured to

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o set the batt in its desired shape.

o 0 o o s A difficulty with this previously proposed method of making 00 0 °fibrous insulation batts is that it can be difficult to impregnate the batt or contact the fibres with the binding 0o substance to a desirable extent so that the final batt has and 0 a0 maintains its desired strength, shape and other physical properties. This particular difficulty is believed to be more prevalent with natural fibres such as cellulose fibres and particularly with animal fibres such as wool fibres because 0000 o5o,:1 these fibre materials are absorbent or otherwise tend to take up the binding substance being sprayed onto the fibrous mat so that the binding substance does not penetrate sufficiently into the thickness of the mat. This problem is not so prevalent with pure synthetic or glass fibres because it is believed such fibres are less absorbent and have a smaller cross-sectional area because generally the fibres are monofilaments. By contrast natural fibres have a larger surface area because the r surfaces are more irregular and/or "bristly".

It is an object of the present invention to provide a method of and apparatus for producing insulation in which the fibres are effectively bound together.

According to the present invention there is provided a.

method of manufacturing an insulating body, the method comprising the steps of: treating a fibrous feed material comprising predominently cellulose material to render the material in the form of substantially separate predominently Ccf cellulose fibres, fluidising the fibres in a gas so as to further separate the fibres and to render them in a low density form, spraying the fibres with a binding substance while the fibres are substantially fluidised so as to thereby generally uniformly contact the fibres with the binding substance and so that the cellulose fibres absorb binding substance, and depositing the sprayed fibres so as to form a body of fibres tE which adhere immediately upon deposition and upon contact with other fibres.

The method according to the invention as outlined will be ,0 t2 0 seen to enable coating or contacting of the majority of the fibres when fluidised, the contacting with the binding substance being particularly uniform rather than predominately the fibres nearest the source(s) of the spray receiving the majority of the binding substance. The expression "uniformly contact" does not mean "completely coat" but simply means all or most fibres have at least some binding substance adhering thereto. The method is applicable particularly to the application of binding substance to natural fibres including both animal and vegetable based fibres wool fibres and cotton or other cellulose Uibres).

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i "S"m I In one embodiment the fibrous feed material includes wool fibres. In a second embodiment, the feed material is selected from the class of predominently cellulose fibrous materials with the exception of wool, the class including cellulose fibres from pulverised paper.

K t S C t 1_ n nnp mhnrd im n thp fihrnii fpd m.at r__ial, incluIdes wopl fibres. In a second embodiment, the ed material is selected from the class of all fibr materials with the exception of wool, the class i uding cellulose fibres, synthetic organic fibres, a inorganic fibres including fibreglass and rock Preferably the step of treating the fibrous feed material to render the material in the form of substantially separate fibres includes a process of ragging, teasing or otherwise doffering the fibrous feed material. The treating step may .o further include feeding the fibres to a carding machine or 0 0 0 doffer to yield a sliver or web of separate fibres, the fibres 0 0 c0 then being combed or teased out to further separate the fibres.

o The step of fluidising the fibres preferably comprises 0 040 entraining or suspending the fibres in an air stream. The step S of treating the fibrous feed material to render it in the form 0 0 0 o0o0 of substantially separate fibres may include contacting the feed 0 OB material by a rotary tined member so as to tease out and 0 0 0 60 separate fibres, the tined member being gas permeable, the step of fluidising the fibres in a gas comprising forcing gas through °oS 0 the gas permeable tined member so as to entrain the fibres as 0 they separate from the tines and to assist in such separation of the fibres from the tines.

In one embodiment the step of fluidising the fibres comprises entraining the fibres in an air stream after they emerge from the combing or teasing out operation so that the fibres enter and travel along a passage in suspension. The step of spraying the fibres with the binding substance while the fibres are substantially fluidised may comprise spraying the at *aa 0441 4 a a 4 I a:: t a suspension of fibres in air as the suspension emerges from an outlet of the passage. Tne fibres and/or spray particles of the binding substance may be electrostatically charged so as to promote attraction of the binding substance particles to the fibres to facilitate uniform contacting of the fibres with the binding substance.

The gas in which the fibres are fluidised may be heated so as to thereby cause heating of the fibres and the binding substance to promote setting of the binding substance. In this case, the binding substance may comprise a self cross linking polymer resin and the deposited body of adherent fibres may be maintained at an elevated temperature for a period of time to promote setting of the resin binder.

The step of depositing the sprayed fibres so as to form a body of adherent fibres may comprise the step of allowing the fibres after spraying with the binding substance to settle onto a surface under quiescent conditions so that a light mat of fibres is formed with a relatively large volume of gas space between the fibres.

In an alternative embodiment, the step of depositing the sprayed fibres so as to form a body of adherent fibres may comprise drawing the fibres after spraying with the binding substance onto a perforated surface by creating a suction on the opposite side of the surface to that upon which the fibres are deposited. In this embodiment, the step of depositing the sprayed fibres may be followed by a further step of blowing heated gas through the perforated surface and through the deposited body of adherent fibres so as to promote setting of a a: c the binding substance. For producing a tubular insulating body, the perforated surface may comprise a perforated tube, the perforated tube being rotated about a longitudinal axis during the deposition of the sprayed fibres onto the outside surface of the tube so as to thereby build up a tubular body of adherent fibres around the outside of the perforated tube.

According to the present invention there is also provided apparatus for carrying out the method as outlined so as to manufacture an insulating body, the apparatus including treating i0 means for treating a fibrous feed material comprising predominently cellulose material to render the material in the form of substantially separate predominently cellulose fibres, fluidising means for fluidi qing the fibres in a gas so as to further separate the fibres and to render them in a low density form, spraying means for spraying the fibres with a binding substance while the fibres are substantially fluidised so as to thereby generally uniformly contact the fibres with the binding S substance and so that the cellulose fibres absorb binding substance, and depositing means for depositing the sprayed fibres so as to form a body of fibres which adhere immediately upon deposition and upon contact with other fibres.

The present invention also relates to insulation material when manufactured by the method or by the apparatus according to the invention.

Possible and preferred features of the present invention will now be described with particular reference to the accompanying drawings but without limiting the invention. In the drawings: Fig. 1 is a schematic drawing for illustrating a process 7 and apparatus according to one possible embodiment of the I~-r*ra~r- present invention, Fig. 2 is a schematic side view of an alternative fibre deposition system usable in the present invention.

Referring to the drawings, the apparatus for carrying out the preferred method comprises treating means 10 for treating a fibrous feed material to render the material in the form of substantially separate fibres.

The fibrous feed material used in the method may include for example wool fibres, both new and previously used. The use of wool fibres in the insulation can be desirable for some end oso uses of the insulating body because of the fire retardant ooo000 oo properties of wool and the resistance of wool fibres to rot and o o vermin. New wool in the form of low quality wool such as dark 0 0 fleeces or scrap cuttings from shearing operations can be used.

00 "o Recycled woollen garments can also be used. It will be appreciated that the fibrous feed material may comprise or 00 SOo include wool blend materials such as will be found in recycled 0 00 garments having wool and other natural or synthetic fibre o00 I oo content. The fibrous feed material may additionally or alternatively include vegetable derived fibrous material, So particularly cellulose materials such as cotton and paper oo fibres. T-e- m~a r cy n rmnri-e or inrl]_dp organic 0 r 1norg n sr aic..,y. .s a tu.rl, .£1amna_ rs ma t e r i a 1 The treating means illustrated schematically in Fig. 1 includes a ragging machine 11 for ragging say scrap fabric and textile materials, piece goods, woollen or woollen blend garments so as to render wool fibres, which are normally in the order of two to three inches in length, into individual fibres generally in the order of about one quarter of inch in length.

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0 o'o 00 0 0000 0000 00 00 00 0 00 00 0 000 00 00en 0 000 0u 00 0 000 00 0 The fibres are fed to a carding machine 12 or doffer to yield a sliver or web 13 of aligned and untangled fibres. The web 13 is then fed through rollers 14 and the fibres are combed or teased out by cylinder 15 which operates in the general manner of a further ragging machine. In particular the cylinder 15 has a large number of radially projecting tines, filaments or wires 16 which contact the fibres of the web 13 and draw them out generally individually to produce a stream 17 of substantially separated fibres.

The next stage in the process comprises fluidising the fibres in a gas so as to further separate the fibres and to render them in a low density form. This substantially separated low density form of the fibres may comprise the stream 17 which may be allowed to fall freely so as to allow the fibres to further separate and adopt a low density form. However preferably as illustrated, the apparatus includes fluidising means 20 for entraining or suspending the fibres in an air stream.

The fluidising means 20 illustrated is operative to entrain the fibres in the stream 17 so that the fibres enter and travel along a passage 21 such as a pipe, in suspension. The fluidising means may comprise a fan or blower 22 such as a Richardson fan, After passing along the passage 21 to a point where the fibres are to be deposited, the suspension of substantially individual fibres and air emerges from an outlet end 23 of the passage 21 in a state such that the particles 24 are still fluidised anu preferably generally uniformally distributed. In Fig, 1 the outlet 23 comprises an outlet nozzle. However if desired the outlet 23 may comprise an 1 -7 outwardly flaring horn, possibly having rotary distributing means within the horn so as to produce a generally uniform density flow of dispersed fibres for deposition on a -elatively wide area.

The apparatus includes spraying means 30 for spraying the fibres 24 with a binding substance while the fibres are substantially fluidised so as to thereby generally uniformally contact the fibres 24 with the binding substance. The sprayed so as to form a body 40 of adherent fibres are then deposited 0 a 0 00 0 000 0 0 00 00 00 0 O0 O 00 20 o 4 1 0 04 0 04 Oog o o 0 0 4o fibres which may have a relatively large volume of air space within the body 40 between the fibres.

In the drawings, the spraying means 30 is arranged to spray the suspension of fibres 24 in air as the suspension emerges from the outlet 23 of the passage 21. For this purpose the spraying apparatus includes nozzles 31 located at the outlet end 23 and arranged to direct sprays 32 of binding substance into the suspension. Preferably the spray 32 is in the form of a very fine mist and for this purpose the nozzles 31 are preferably atomising nozzles.

To facilitate uniform contacting of the fibres 24 with the binding substance, the fibres 24 and/or the particles in the spray 32 may be electrostatically charged so as to promote attraction of the binding substance particles to the fibres 24.

For example the binding substance particles may be charged to say about 60,000 volts while the fibres 24 are uncharged. As is know in electrostatic spray painting, such a potential difference between the spray particles and the object being sprayed will substantially enhance coating or contacting of the fibres with the binding substance.

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i-il rm*ii 00 0 0)00 0o0 o o 20 00 0oe 0 00 00 0 00 0 00# 00 0 01 0 000 0 04 0 00r 0 01 00 0 000 s 0000& 0 0 Heated air may be used to fluidise the fibres or may be directed into the suspension emerging from the passage 21 so as to heat the fibres 24 and the binding substance to accelerate setting of the binding substance. 160'C is a suitable temperature for setting some resin binding substances. In Fig.

1 the apparatus includes heating apparatus 45 which may be for example a gas fired furnace with a heat exchanger through which air is forced, the air then being used to fluidise or heat the fibres. As shown in Fig. 1 the heated air may be directed around the outside of the cylinder 15 as shown at A or may be directed firstly axially into the cylinder 15 as shown at B.

The cylinder 15 may be air permeable and the heated air may be directed generally radially outwardly through the permeable cylinder 15 through nozzle 46 so as to mix with and entrain the fibres as they form the stream 17. The heated air passing through the cylinder 15 may assist separation of the fibres from the tines 16.

The binding substance may be any suitable material. For example the binding substance may comprise a resin material together with an appropriate catalyst. The resin may also serve, in addition to being a binding substance, as a flame and/or smoke suppressant. It will be appreciated that any desired additives can be included in the binding substance spray such as a pesticide Perigen available from Burroughs Wellcome). Aluminium trihydrate and Chemgard can be added as smoke suppressants The resin may be a flame depressant resin such as Rhoplex Ha-20, available from Rhon and Hass. Another possible or alternative additive as a fire/smoke retardant would be Flovan which is believed to be an ionic compound. This substance is available from Ciba-Geigy.

The preferred resin substance for some applications may be a self cross linking polymer resin and the deposited body of adherent fibres may be maintained at an elevated temperature for a period of time to promote setting of the resin binder, e.g. at say 150 0 C for three minutes.

The deposition of the sprayed fibres 24 so as to form a body 40 of adherent fibres in Fig. 1 comprises allowing the emerging suspension of fibres in air after spraying to settle 10 onto a surface 43. This settling can be carried out under S t quiescent conditions so that a light mat 41 of fibres is formed S with a relatively large volume of air space between fibres.

S With the use of heated air and suitable catalysts added to the oat a resin, the fibres can be made to bind together with good shape retaining properties as soon as they settle against each other.

The surface 43 on which the fibres settle to form the mat 41 4,4" steadily moves away from the settling zone so as to enable the mat 41 to be formed on a continuous basis. The speed of movement of the surface 43, which is illustrated in Fig. 1 as a belt surface, may be variable to enable control of the thickness of the mat 41 formed. The outlet 23 of the passage 21 from which the suspension of fibres in air emerges may be reciprocated in a transverse direction to promote uniformity of the spatial density of settling fibres on the surface 43.

In addition to setting of the binding substance promoted by the use of heated air, further curing of the resinous binding material may be promoted in any known way. For example the mat 41 may be passed through an oven (not shown) for accelerating the setting of the binding substance. The mat 41 may be cut to ~i desired shaped and sized pieces for packaging and use in particular environments, e.g. as thermal insulation in building walls and ceilings or as thermal and/or accoustic insulation in wall panels. The mat 41 or batt after setting of the binding substance will have a resilience enabling the mat 41 to be compressed for packaging purposes but will spring back to occupy substantially its originel volume with a large volume of air space between the fibres upon release of the compressive force.

In Fig. 2 the surface 43 onto which the sprayed fibres 24 are deposited comprises a perforate, tube 50 which is rotated about its longitudinal axis 51 during the fibre deposition. For this purpose the tube 50 is supported by bearings 52 and can be #4 rotated by any suitable drive means (not shown). The fibres 24 after spraying with the binding substance are drawit onto the perforated surface of the tube 50 by creating a suction on the inside of the perforated tube 50. This may be achieved by any suitable suction apparatus 53. As the tube 50 is rotated a mat 54 of fibres builds up on the outside of the tube 50. The density of the fibres in the mat 54 can be controlled by controlling the suction. The size of the perforations in the tube 50 shown in Fig. 2 is exaggerated for clarity.

After depositing of the sprayed fibres onto the surface 43, heated gas can be blown through the perforated surface and through the deposited body 54 so as to promote setting of the binding substance. For this purpose the source 45 of heated air (Fig. 1) can be used to supply heated air which is blown through the tube 50 and out through the perforations and through the mat 54. The outer end 55 of the tube 50 is closed.

After the cylindrical matt 54 has at least partially set, the mat can be removed from the tube 50 by sliding it off the end 55. The blowing of air through the perforations in the tube during the setting of the binder will help remove fibres from the perforations. To facilitate removal of the mat 54, the outside surface of the tube 50 may be coated with a non-stick surface such as Teflon. Also the tube 50 may have a slight taper towards the end 55, e.g. in the order of to 1 which will not be significant in the use to which the tubular insulating body 54 is put.

110 The tubular mat 54 can be used say for pipe lagging and for -this purpose may be slit longitudinally to allow the lagging to be applied to the outside surface of a pipe. Preferably a neutral pH resin binder is used if the insulation is for metal pipe lagging to avoid a possible cause of pipe corrosion or electrolysis The treating means 10 has been schematically illustrated and described in relation to using wool, recycled garments etc.

as the original feed material. However cellulose materials can be included in the feed material. To use such material for the fibres, the treating means 10 may include say a hammer mill for pulverising paper such newsprint. The hammer mill may be operative to reduce th? material to a fluff in which the fibres are substantially separated. Fire retardant and other additives may be incorporated in the processing of the cellulose material, e.g. as described in Australian Patent Specification No.

29,407/84 (Patent No. 555,047).

T. a, P .t h f-4& fibr e p whe e" iz y t _9 u e d as a source of fibre materil,.,a high speed rotary chopper may 13.

It will be seen that the method and apparatus for producing insulation according to the present invention enables elimination of the lapping machine used in the previously proposed process. The spraying of binding substance into the fibres while fluidised will more effectively and uniformly contact the fibres with the binding substance.

The present invention also provides insulation material when manufactured by the method or apparatus of the present invention.

In addition to insulation material in the form of mat or batts, the insulation material after manufacture may be broken 1:4 F into lumps or particles (but not down to individual fibres again) so that the insulation can be sprayed into a space in the form of a fluff as is know for building insulation purposes.

It is to be understood that various alterations, modifications and/or additions may be made to the features of the possible and preferred embodiment(s) of the invention as herein described without departing from the scope of the invention as defined in the appended claims.

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Claims

2-, The claims defining the invention are as follows: 1. A method of manufacturing an insulating body, the method comprising the steps of: treating a fibrous feed material comprising predominently cellulose material to render the material in the form of substantially separate predominently cellulose fibres, fluidising the fibres in a gas so as to further separate the fibres and to render them in a low density form, spraying the fibres with a binding substance while the fibres are substantially fluidised so as to thereby generally uniformly contact the fibres with the binding substance and so that the cellulose fibres absorb binding substance, and G depositing the sprayed fibres so as to form a body of fibres which adhere immediately upon deposition and upon contact with other fibres. 2. A method as claimed in Claim 1 wherein the fibrous feed material includes wool fibres.
3. A method as claimed in Claim 1 wherein the feed material is -selected from the class of predominently cellulose fibrous materials with the exception of wool, said class including ?0 fibres from pulverised paper.
4. A method as claimed in Claim 3 wherein the fibres comprise paper which has been fed to a hammer mill so as to pulverise the paper to produce a cellulose fluff. A nethod as claimed in any one of Claims 1 to 3 wherein the step of treating the fibrous feed material to render the material in the form of substantially separate fibres includes a process of ragging, teasing or otherwise doffering the fibrous feed material.
6. A method as claimed in Claim 5 wherein the treating step further includes feeding the fibres to a carding machine or doffer to yield a sliver or web of separate fibres, the fibres then being combed or teased out to further separate the fibres.
7. A method as claimed in any one of Claims 1 to 6 wherein the step of fluidising the fibres comprises entraining or suspending the fii res in an air stream.
8. A method as claimed in Claim 7 wherein the step of treating the fibrous feed material to render it in the form of I0 substantially separate fibres includes contacting the feed f' material by a rotary tined member so as to tease out and H separate fibres, the tined member being gas permeable, the step S of fluidising the fibres in a gas comprising forcing gas through the gas permeable tined member so as to entrain the fibres as they separate from the tines and to assist in such separation of the fibres from the tines.
9. A method as claimed in Claim 6 wherein the step of fluidising the fibres comprises entraining the fibres in an air stream after they emerge from the combing or teasing out operation so that the fibres enter and travel along a passage in suspension, step of spraying the fibres with the binding substance while the fibres are substantially fluidised comprising spraying the suspension of fibres in air as the suspension emerges from an outlet of the passage.
10. A method as claimed in any one of the preceding claims wherein the fibres and/or spray particles of the binding substance are electrostatically charged so as to promote attraction of thL binding substance particles to the fibres to I1 Pr pi16 facilitate uniform contacting of the fibres with the binding substance.
11. A method as claimed in any one of the preceding claims wherein the gas in which the fibres are fluidised is heated so as to thereby cause heating of the fibres and the binding substance to promote setting of the binding substance.
12. A method as claimed in Claim 11 wherein the binding substance comprises a self cross linking polymer resin and the deposited body of adherent fibres is maintained at an elevated 1 temperature for a period of time to promote setting of the resin binder.
13. A method as claimed in any one of the preceding claims wherein the step of depositing the sprayed fibres so as to form a body of adherent fibres comprises the step of allowing the fibres after spraying with the binding substance to settle onto a surface under quiescent conditions so that a light mat of fibres is formed with a relatively large volume of gas space between the fibres.
14. A method as claimed in one of Claims 1 to 12 wherein the step of depositing the sprayed fibres so as to form a body of adherent fibres comprises drawing the fibres after spraying with the binding substance onto a perforated surface b, creating a suction on the opposite side of the surface to that upon which the fibres are deposited.
15. A method as claimed in Claim 14 wherein the step of depositing the sprayed fibres is followed by a further step of blowing heated gas through the perforated surface and through the deposited body of adherent fibres so as to promote setting of the binding substance.
16. A method as claimed in Claim 14 or 15 wherein the perforated surface comprises a perforated tube, the perforated r tube being rotated about a longitudinal axis during the deposition of the sprayed fibres onto the outside surface of the Stube so as to thereby build up a tubular body of adherent fibres around the outside of the perforated tube.
17. Apparatus for carrying out the method as claimed in any one of the preceding claims so as to manufacture an insulating body, the apparatus including treating means for treating a fibrous feed material comprising predominently cellulose material to render the material in the form of substantially separate predominently cellulose fibres, fluidising means for fluidising the fibres in a gas so as to further separate the fibres and to render them in a low density form, spraying means for spraying the fibres with a binding substance while the fibres are substantially fluidised so as to thereby generally uniformly contact the fibres with the binding substance and so that the cellulose fibres absorb binding substance, and depositing means for depositing the sprayed fibres so as to form a body of fibres which adhere immediately upon deposition and upon contact with other fibres.
18. Insulation material when manufactured by the method as claimed in any one of Claims 1 to 16 or when manufactured by the apparatus as claimed in Claim 17.
19. A method of and apparatus for manufacturing an insulating body substantially as herein before described with particular reference to the accompanying drawings. Dated this 22nd day of August, 1990 TENT ATTORNEY SERVICES 4ttorneys for AUSTRALIAN CELLULOSE INDUSTRIES PTY. LTD.