GB1591843A

GB1591843A - Material depositor

Info

Publication number: GB1591843A
Application number: GB11276/77A
Authority: GB
Original assignee: Tarmac Ltd
Current assignee: Tarmac Ltd
Priority date: 1978-01-13
Filing date: 1978-01-13
Publication date: 1981-06-24

Description

(54) A NEW OR IMPROVED MATERIAL DEPOSITOR (71) We, TARMAC LIMITED, a British Company of P.O. Box 8, Ettingshall, Wolverhampton, WV4 6JP, do hereby declare this invention for which we pray that a Patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to a machine and a method for mixing and depositing composite materials. The term "composite materials" as used in this Specification is intended to rnean materials which are formed from a flowable, e.g. liquid or powder component and a finely divided particulate or fibrous component which is homogeneously distribrted throughout the flowable component. The composite material may be of a type intended to remain in liquid form or may be curable to a solid condition.

The term "liquid" includes viscous and pasty materials capable of flowing gravitationally, either independently or when vibrated.

The machine and method of this invention were devised principally for the mixing and depositing of glass fibre reinforced cement (grc) but may be used in the production of other composite materials, especially where a relatively fragile component is being added.

At present, grc is usually made by a spraying technique although other methods can be used, for example the hydration of a dry premix. In the spray technique, a slurry of Portland or other suitable cement, together with sand and/or other fillers, is formed with water and this is sprayed into a mould or onto a substrate simultaneously with quantities of chopped glass fibre. This fibre is usually of zirconium glass, which is resistant to alkaline attack by the cement.

Such spraying methods do not readily lend themselves to mass production and grc has therefore not been widely used to date, except where its special properties have been specifically called for.

It is an object of the present invention to provide a machine for mixing and depositing composite materials as herein defined and especially grc, said machine being capable of continuous operation.

According to the invention there is provided a machine for mixing and depositing composite materials as herein defined, the machine comprising reservoir means for a flowable component of the material, the reservoir means having outlet means of elongate form, guide means for guiding the flowable component leaving the outlet means, said guide means being so shaped that the flowable component flows in one or more films partly or wholly surrounding a region of space and converging below said region, continuous supply means for continuously supplying a fibrous or particulate component of the material into said region so as to become mixed with the flowing film or films; means for causing the mixed material to undergo one or more changes of direction; and a discharge orifice for discharging the material from the machine.

Control means may be provided for controlling the flow of said flowable component through the outlet means.

The means for causing the mixed material to undergo a change of direction may comprise flow interruption means to receive the material after said films have converged. The flowinterruption means may comprise a plate which may be flat, upwardly concave or convex in form and disposed generally horizontally or in any chosen orientation. The plate may undergo periodic movement for example it may be vibrated or may be moved from side to side in any suitable form of periodic motion or may be periodically tilted.

There may be further guide means adjacent the orifice for changing the direction of flow of the mixed material immediately prior to discharge.

The invention also provides a method of mixing and depositing composite materials as herein defined and especially grc, the method comprising the steps of causing a flowable component of the material to flow in or or more films partly or wholly surrounding a region of space and converging below said region, continuously supplying a fibrous or particulate component of the material into said region so as to become mixed with the flowing film or films; causing the mixed material to undergo one or more changes of direction, and discharging the material through an orifice.

The flow of the mixed material may be interrupted or may be caused to change its direction immediately prior to discharge.

The invention will now be described in more detail by way of example only with reference to the mixing and depositing of grc by a machine as shown in the accompanying drawings in which: FIGURE 1 is an end elevation, partly in section of a first embodiment of machine, FIGURE 2 is an end elevation, partly in section of a second embodiment of machine, FIGURE 3 is a diagram illustrating mixing using the apparatus of Figure 2, FIGURE 4 illustrates movement of the hopper and catchment plate and, FIGURE 5 illustrates movement of the catchment plate only.

It will be appreciated that, although the invention is described in relation to mixing and depositing grc, the apparatus and method of the invention can be used for mixing and depositing other composite materials as hereinbefore defined.

The machines shown in Figures 1 and 2 of the drawings are basically similar in that each comprises a pair of elongate reservoirs which are somewhat trough-like in form and which are intended to supply a cement/water slurry through respective outlets in the reservoirs.

Each outlet is elongate and restricted in crosssection and the slurry is supplied through the outlet at a predetermined rate such that it falls or flows downwardly in a film which is guided by the guide means.

The slurry emanating from the reservoirs is guided so that the films tend to converge and a region of space is defined between, and partly surrounded by the films.

Chopped zirconium glass fibre is continuously supplied in randomly oriented lengths to the region between the films which are then caused to flow together below the region referred to so that the gloss fibres are intimately mixed with the cement slurry. The slurry is then discharged in a generally horizontal direction, having undergone a change in its direction of flow. Discharge takes place through an elongate orifice which can discharge the material onto a continuous belt, a platen moved under the orifice, a succession of moulds or in any other way.

Having briefly outlined the features of over all similarity of the two embodiments of machine shown, we now refer more specifically to the embodimcnt shown in Figure 1 of the drawings.

The machine is shown in end elevation, partly in section. It comprises a pair of troughlike cement slurry reservoirs 10, each of which is provided with an inlet pipe 11, through which a cement slurry is introduced. The slurry may comprise water and Portland or other suitable cement and may include any additives such as fillers, hardeners, accelerators or colouring matter for example.

Each reservoir 10 has a plurality of holes 12 provided in its end which can be used for cleaning purposes, to introduce additives, to pressurize the reservoir or for other reasons.

The outlet from each reservoir is in the form of an elongate slot generally indicated at 13 which is defined between a front plate 14 and a lip 15. The slot 13 creates a weir over which the slurry flows.

Because the slot 13 is elongate, the slurry emerges from the reservoir in a film of constant thickness, the thickness being controlled by the spacing of the elements defining the weir and/or by the pressure or head of slurry in the reservoir.

The weir can therefore control the flow of slurry and, to this end, it may be made adjustable. In Figure 1 adjustment is carried out by means of a quadrant plate 16 which is angularly movable and which is clamped at a selected position by a clamping nut and bolt assembly 17, so as to vary the size of the slot 13 at the weir.

Another factor which may determine the rate at which the slurry flows is its viscosity and, to prevent any fluctuation in viscosity due to settlement of cement in the reservoirs, some form of agitation means is preferably employed.

This can comprise, for example, a mechanical agitator disposed in the reservoir or ultrasonic means coupled to the reservoir.

As the slurry emerges from the reservoir 10 it flows downwardly in a film which is guided at each side of the apparatus by a respective guide plate 18. The guide plates are elongate and generally parallel but converge at their lower ends. A region of space 19 therefore exists between the plates 18 and hence between the falling or flowing films of slurry.

Glass fibre is introduced to the region 19 between the films of cement slurry and is caused to fall or is propelled downwardly so as to become intimately and uniformly mixed with the cement slurry of the films.

The films are caused to flow together as they leave the lower ends of the guide plates and the mixed material then meets a further guide plate 20 which guides the material to a discharge orifice 21 which is directed sidewardly.

It will be appreciated that, if the cement slurry and glass fibre are continuously supplied at the top of the machine, the mixed material emerges from the orifice 21 in a continuous film and can be deposited onto a moving belt, platens, or into moulds for example, to form any desired structure.

Vibration or agitation means can be associated with the discharge orifice to ensure that settlement of the material does not take place between its mixing and its discharge from the machine.

The glass fibre can be introduced from a supply of previously chopped glass fibre lengths or can be supplied from a cutter which is fed with continuous filament glass at a position spaced above the region 19.

The discharge orifice 21 can be made adjustable in size, for example by means of a quadrant plate 22 which can be adjusted to restrict or to expand the orifice.

Referring to Figure 2 of the drawings, the same reference numerals are used to denote similar parts of the apparatus. The supply of cement slurry over adjustable weirs from the supply reservoirs is not shown in detail but after the cement slurry emerges from the weir at the outlet slot 13 of the reservoir 10, the film of slurry is caused to fall or flow through a pivoted hopper 23 which can be swung from side to side by means of a link 24 pivotally mounted on an eccentric arrangement generally indicated at 25. The drive shaft of the eccentric can be rotated by hand or by a motor.

The hopper 23 guides the slurry films towards each other and a region 19 is defined within the hopper. The glass fibre is supplied into the hopper and, by the time the films coalesce after passing through the hopper, the preliminary mixing of the glass fibre and the cement slurry has taken place.

The rocking or swinging motion of the hopper then tends to pour the mixture in a series of overlapping layers which tends to blend the material and ensure thorough and even mixing of the glass fibre into the slurry.

The hopper may discharge the material directly to the discharge orifice 21 but preferably there is a plate 26 provided below the hopper onto which the overlapping "folds" of material from the hopper fall. This plate may be vibrated. Alternatively, or in addition, the plate may be periodically moved from side to side with a sinusoidal or square-wave oscillation or may be tilted about a generally horizontal axis, for example in timed relation with the swinging of the hopper 23, to assist in the thorough mixing of the components. (See Figures 4 and 5).

It will be appreciated that the discharge of material from the orifice 21 may not take place at precisely the same rate as the supply of slurry and glass fibre and hence there may be a build up of material in the throat above guide plate 20. Without the presence of the plate 26, the distance fallen by the mixture coming from the hopper would vary according to the depth of material in the throat of the discharge orifice and hence mixing might not be even.

The plate 26 is shown as having a slightly convex surface but could be provided with a flat surface or with a concave surface directed upwardly. The angle at which the plate is mounted, together with the type of movement which it may undergo and/or the vibration of the plate may be chosen so as to give optimum results in mixing the material passing through the machine.

The discharge orifice 21 is again directed sidewardly and can be varied in size by means of a rotatable element carrying a flap 22 which limits the upper extent of the orifice.

It is envisaged that the machine described above can be used to produce a film of grc up to several metres in width, provided that the flow of the films through the machines can be accurately controlled. It would also be possible to arrange for a single reservoir to be used for the slurry and this might have one elongate or circular discharge outlet for example or arcuate or circular discharge outlet for example or might have a pair of spaced parallel linear elongate discharge outlets similar to the arrangement described above.

The material discharged at the discharge orifice 21 can be used in any manner and this does not form a part of the invention.

Various other composite materials than grc can be mixed and deposited using the apparatus of the invention although changes may be needed to take into account the viscosity of the flowable component, the amount of fibrous or particulate material to be added and the manner in which the composite material is to be discharged.

The machine is principally intended to mix fragile components such as glass fibres, glass spheres or fragile lightweight aggregates into a material without causing damage to the fragile component. For example, in the mixing of glass fibre into a cement slurry, it is essential that the glass fibre should not be roughly treated during mixing since damage to the fibre would weaken the reinforcing effect which the fibre should have on the cement.

WHAT WE CLAIM IS:- 1. A machine for mixing and depositing composite materials as herein defined, the machine comprising reservoir means for a flowable component of the material, the reservoir means having outlet means of elongate form; guide means for guiding the flowable component leaving the outlet means, said guide means being so shaped that the flowable component flows in one or more films partly or wholly surrounding a region of space and converging below said region; continuous supply means for continuously supplying a fibrous or particulate component of the material into said region so as to become mixed with the flowing film or films; means for causing the mixed material to undergo one or more changes of direction; and a discharge orifice for discharging the material from the machine.

2. A machine according to Claim 1 wherein control means are provided for controlling the flow of said flowable component through the outlet means.

3. A machine according to Claim 1 or Claim 2 wherein the means for causing the mixed

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. The glass fibre can be introduced from a supply of previously chopped glass fibre lengths or can be supplied from a cutter which is fed with continuous filament glass at a position spaced above the region 19. The discharge orifice 21 can be made adjustable in size, for example by means of a quadrant plate 22 which can be adjusted to restrict or to expand the orifice. Referring to Figure 2 of the drawings, the same reference numerals are used to denote similar parts of the apparatus. The supply of cement slurry over adjustable weirs from the supply reservoirs is not shown in detail but after the cement slurry emerges from the weir at the outlet slot 13 of the reservoir 10, the film of slurry is caused to fall or flow through a pivoted hopper 23 which can be swung from side to side by means of a link 24 pivotally mounted on an eccentric arrangement generally indicated at 25. The drive shaft of the eccentric can be rotated by hand or by a motor. The hopper 23 guides the slurry films towards each other and a region 19 is defined within the hopper. The glass fibre is supplied into the hopper and, by the time the films coalesce after passing through the hopper, the preliminary mixing of the glass fibre and the cement slurry has taken place. The rocking or swinging motion of the hopper then tends to pour the mixture in a series of overlapping layers which tends to blend the material and ensure thorough and even mixing of the glass fibre into the slurry. The hopper may discharge the material directly to the discharge orifice 21 but preferably there is a plate 26 provided below the hopper onto which the overlapping "folds" of material from the hopper fall. This plate may be vibrated. Alternatively, or in addition, the plate may be periodically moved from side to side with a sinusoidal or square-wave oscillation or may be tilted about a generally horizontal axis, for example in timed relation with the swinging of the hopper 23, to assist in the thorough mixing of the components. (See Figures 4 and 5). It will be appreciated that the discharge of material from the orifice 21 may not take place at precisely the same rate as the supply of slurry and glass fibre and hence there may be a build up of material in the throat above guide plate 20. Without the presence of the plate 26, the distance fallen by the mixture coming from the hopper would vary according to the depth of material in the throat of the discharge orifice and hence mixing might not be even. The plate 26 is shown as having a slightly convex surface but could be provided with a flat surface or with a concave surface directed upwardly. The angle at which the plate is mounted, together with the type of movement which it may undergo and/or the vibration of the plate may be chosen so as to give optimum results in mixing the material passing through the machine. The discharge orifice 21 is again directed sidewardly and can be varied in size by means of a rotatable element carrying a flap 22 which limits the upper extent of the orifice. It is envisaged that the machine described above can be used to produce a film of grc up to several metres in width, provided that the flow of the films through the machines can be accurately controlled. It would also be possible to arrange for a single reservoir to be used for the slurry and this might have one elongate or circular discharge outlet for example or arcuate or circular discharge outlet for example or might have a pair of spaced parallel linear elongate discharge outlets similar to the arrangement described above. The material discharged at the discharge orifice 21 can be used in any manner and this does not form a part of the invention. Various other composite materials than grc can be mixed and deposited using the apparatus of the invention although changes may be needed to take into account the viscosity of the flowable component, the amount of fibrous or particulate material to be added and the manner in which the composite material is to be discharged. The machine is principally intended to mix fragile components such as glass fibres, glass spheres or fragile lightweight aggregates into a material without causing damage to the fragile component. For example, in the mixing of glass fibre into a cement slurry, it is essential that the glass fibre should not be roughly treated during mixing since damage to the fibre would weaken the reinforcing effect which the fibre should have on the cement. WHAT WE CLAIM IS:-

1. A machine for mixing and depositing composite materials as herein defined, the machine comprising reservoir means for a flowable component of the material, the reservoir means having outlet means of elongate form; guide means for guiding the flowable component leaving the outlet means, said guide means being so shaped that the flowable component flows in one or more films partly or wholly surrounding a region of space and converging below said region; continuous supply means for continuously supplying a fibrous or particulate component of the material into said region so as to become mixed with the flowing film or films; means for causing the mixed material to undergo one or more changes of direction; and a discharge orifice for discharging the material from the machine.

material to undergo a change of direction include flow interruption means to receive the material after said films have converged.

4. A machine according to Claim 3 wherein the flow interruption means comprises a plate.

5. A machine according to Claim 4 wherein the plate is flat.

6. A machine according to Claim 4 wherein the plate is upwardly concave.

7. A machine according to Claim 4 wherein the plate is upwardly convex.

8. A machine according to any one of Claims 4 to 7 wherein the plate undergoes periodic movement.

9. A machine according to any preceding claim wherein the means for causing the mixed material to undergo a change of direction in dude further guide means are provided adjacent the orifice for changing the direction of flow of the material immediately prior to discharge.

10. A machine for mixing and depositing composite materials as hercin defined, substantially as hereinbefore described with reference to and illustrated in Figure 1 of the accompanying drawings.

11. A machine for mixing and depositing composite materials as herein defined, substantially as hereinbefore described with reference to and as illustrated in Figure 1 modified by Figure 2 of the drawings.

12. A machine for mixing and depositing composite materials as herein defined, substantially as hereinbefore described with reference to and as illustrated in Figure 1 as modified by Figure 3, 4 or 5 of the accompanying drawings.

13. A method of mixing and depositing composite materials as herein defined, the method comprising the steps of causing a flowable component of the material to flow in one or more films partly or wholly surrounding a region of space and converging below said region; continuously supplying a fibrous or particulate component of the material into said region so as to become mixed with the flowing film or films; causing the mixed material to undergo one or more changes of direction, and discharging the material through an orifice.

14. A method according to Claim 13 wherein the step of causing the mixed material to undergo a change of direction includes interrupting the flow of the material after said films have converged.

15. A method according to Claim 13 or 14 wherein the step of causing the mixed material to undergo a change of direction includes diverting the material by guide means immediately prior to discharge.

16. A method of depositing a composite material substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.