GB2121853A

GB2121853A - Applicator for applying a surface dressing

Info

Publication number: GB2121853A
Application number: GB08217460A
Authority: GB
Inventors: Graham Beeney
Original assignee: CAR DECK MAINTENANCE Ltd
Current assignee: CAR DECK MAINTENANCE Ltd
Priority date: 1982-06-16
Filing date: 1982-06-16
Publication date: 1984-01-04
Also published as: GB2121853B; ES279370Y; ES279370U

Abstract

An attachment for mounting to a vehicle for applying a surface dressing of binder reinforced with glass fibres comprises two spray bar housings (1, 3) mounted to the front and rear of an open-bottomed distribution box (2) through which is discharged chopped glass fibres for deposition into the layer of binder applied from the leading spray bar in use of the attachment. <IMAGE>

Description

SPECIFICATION Applicator for applying a surface dressing This invention relates to an applicator, more specifically to an attachment for mounting to a vehicle, for applying a surface dressing of tar and/or bituminous binder material reinforced with glass fibres.

In our British Patent Application No. 81 13914, published under No. 2081603, we describe the provision of a surface dressing to which a substrate to be surfaced has sprayed thereon a binder which is reinforced with chopped glass fibres with a suitable aggregate then being added to the thus coated substrate to be bound thereto by the same binder as has been reinforced with the chopped glass fibres. In order to obtain the requisite degree of impregnation and reinforcement of the surface to be covered and of the reinforcing glass fibres we have, prior to the present invention, applied the binder and chopped glass fibres by hand using a distribution wand comprising two bituminous sprays with the glass fibre being discharged from a chopper outlet between the two sprays.As the operator sweeps the applicator across the ground one spray applies an initial layer of binder with the chopped glass fibres being applied to that binder and with a subsequent spray then being applied over the top thereof, the surface dressing then being applied to the top layer of binder for subsequent rolling to form the final surface dressing. We have now found that adequate control of the treatment can be obtained using a mechanized spray bar with the degree of impregnation of the glass fibre being achieved, at least to a major extent, simply by the glass fibre sinking into the layer of freshly applied binder without requiring the same degree, if any, of subsequent binder application due to the surprising extent to which the light chopped glass fibres properly deposited on the surface of the binder will sink into that binder to provide the necessary reinforcement action.

According to the present invention, we provide an attachment for mounting to a vehicle for applying a surface dressing of tar and/or bituminous binder material reinforced with glass fibres, such machine comprising an attachment for mounting to a vehicle for applying a surface dressing of tar and/or bituminous binder material reinforced with glass fibres, such a machine comprising an open-bottomed spray bar housing for attachment to a vehicle, a spray bar mounted to said housing for spraying binder material from a plurality of nozzles placed longitudinally of the spray bar housing to extend transversely of movement of the vehicle when mounted thereon, means for controlling operation of the nozzles and a glass fibre distributor mounted to said spray bar housing and comprising an open bottomed box mounted to extend the length of the spray bar housing and means for depositing cut glass fibres through said open bottom of the box to the surface of binder material previously sprayed from the spray bar nozzles during use of the Preferably a second spray bar housing with spray bar is secured to the distributor at the side thereof opposite to said first spray bar. The second spray bar has fewer nozzles than the first spray bar so that the thickness of a layer of binder applied therefrom is less than that of the first spray bar.By having the second spray bar controllable independently of the first spray bar, it can be achieved that the second spray bar is only used to apply binder when the binder is being applied on a more absorbent surface than usual, such that there is a smaller depth of binder initially applied into which the fibre glass can sink to provide the necessary net-like strengthening.

Preferably, the distributor comprises a pneumatically powered chopper, means for supplying a tow of glass fibres to the chopper, means for supplying compressed air to the chopper for both driving the chopper and for spraying the chopped lengths of fibre glass therefrom and means for controlling the supply of compressed air. By having this control the attachment can be used to supply binder to form a layer of a depth dependent on the speed of the vehicle to which the attachment is applied with the proportion of glass fibre in the binder being varied by changing the rate of supply of compressed air which thus controls the speed of operation of the chopper.

A particularly convenient form of distributor comprises two choppers provided to discharge into respective opposite ends of the distributor box with the choppers themselves being staggered in the direction of movement of the vehicle whereby the distribution patterns of the glass fibres discharged from each of the two choppers provide for an even distribution across the length of the distributor box transversely of the direction of movement of the vehicle during such vehicle movement. Means may be provided for attaching a hopper of aggregate for surface dressing to the rear of the attachment. Such a hopper may simply comprise a wheeled trailer arranged to follow the vehicle provided with the attachment to distribute a metered quantity of top-dressing onto the glass fibre reinforced binder for subsequent rolling.

The invention will be further described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a perspective view showing the overall arrangement of two spray bar housings on either side of a chopped fibre glass distributor with all ancillary attachments removed; Figure 2 is a side view of an attachment embodying the invention; Figure 3 is a rear view of the attachment of Figure 2; and Figure 4 is a diagrammatic illustration showing the distribution pattern from two choppers supplying chopped fibre glass to-the interior of the distributor.

Referring to Figure 1 there is shown a spray bar housing 1 which has an open bottom and is provided with a plurality of nozzles for ejecting conical sprays of binder onto a surface being dressed. This spray bar is quite conventional, except for the provision of the distributor 2 at the rear side thereof, and may conveniently comprise fifteen separate spray heads. The distributor 2 comprises an open bottomed box having containers 5 and 6 mounted on top thereof for receipt of coils of fibre glass tow for feeding to choppers mounted at each end of the box, although these choppers are not shown in Figure 1. All that is shown in Figure 1 is an aperture at one end of the distributor box for the receipt of the nozzle from a chopper 20 illustrated in the other Figures.To the rear side of the distributor box 2 there is provided a second spray bar housing 3 for receipt of a spray bar generally conventional and similar to that of the forward main spray bar 1 with the exception that fewer spray heads are provided aiong the length of the spray bar housing 3. Typically two, four or six spray heads may be provided since all that is required is for a thin layer of binder to be applied to cover over any chopped fibreglass which may not have completely sunk into the binder applied from the first spray bar 1 in use of the attachment.

The arrangement of various ancillary devices can better be seen from the diagram of Figure 2. In this diagram an attachment bar 14 is shown mounted to the forward side of the spray bar housing 1 for securement of the attachment to the rear of a vehicle, conventionally a tanker from which liquid binder is supplied, under pressure, by hoses to feed conduits of the first and second spray bars. The first spray bar can be seen as comprising a plurality of spray nozzle heads 1 6, from which conical jets 10 of binder are projected.

The heads 16 are connected by valves individual thereto to a supply conduit 1 5 connected to the binder supply hose. The valves 1 7 of the individual nozzles each have an operating lever projecting therefrom connected by a bar 18 to an operating lever 12, actuation of which can cause all the valves 17 simultaneously to be opened or closed as required. A similar arrangement having an actuating lever 13 is shown for the rear spray bar with the individual jets 11 being non-circular so as to provide the required thin covering of secondary binder over the full length of the spray bar housing 3. Operation of the secondary spray bar is controlled by the lever 13 being operable dependently of the lever 12.

The distributor 2 comprises an open-bottomed rectangular cross-section box with pneumatically powered choppers and 20' provided at each end thereof. Pressure control lines 22 and 22' extend to the choppers 20 and 20' from a valve 25 connected to a source of compressed air. The usual filter and/or separating means are provided for ensuring that any solid and liquid oii contaminants are separated from the air before it is passed to the choppers. As shown, the control valve and the filters can all be incorporated in the one location 25 to which compressed air is fed to an inlet 24 from a compressor which may be mounted on the distributor or on the vehicle, depending on which is the more convenient.

Conventionally, the filter means will be provided just downstream of the compressor although in some cases, they may be incorporated in the one location 25 as shown. The conduit 21 lead from the fibreglass storage boxes 5 and 6 to the choppers 20 and 22. The choppers themselves are of a conventional type as used for applying glass fibres in making glass fibre reinforced plastics mouldings and each comprises a rotary pneumatically powered cutter which drags in a tow of glass fibres which is chopped into lengths approximately 25 millimetres long for subsequent blowing out in a stream of air at high speed to the interior of the distributor box. No specific description of the chopper is required as they are conventional commercially available products available from a number of different manufacturing sources.

The pattern of distribution of the glass fibre through the bottom of the distributor box can be appreciated from the illustration of Figure 4, where the area 30 illustrates the area of predominant receipt of chopped glass fibre from the chopper 20 whereas the area 30' illustrates the predominant area of deposit from the chopper 20'. As will be noted the choppers 20 and 20' are staggered in the direction of movement of the attachment in use thereof, so that the area 30 is at the opposite end of the distributor from the chopper 20 with the maximum density of deposit as being at the edge of the distributor remote from the chopper 20. With a similar arrangement from the chopper 20' of the area 30' a substantially even spread of chopped glass fibre is achieved by operation of the choppers during forward advancement of the attachment at the rear of the vehicle.

The binder as applied in use of this apparatus, is a conventional tar or bitumen emulsion binder with tar, bitumen or a tar and bitumen blend being used as convenient. Whereas normally applied hot, for example, using K.170 bitumen which is a normal 70% bitumen emulsion, it can also be applied cold, for example, with K.160 which contains 60% bitumen. In a particular embodiment, the operation of the spray bars is arranged so that a suitable thickness of bitumen is applied when the vehicle to which the attachment is secured is moved forwardly at a speed of 1 to 2 kilometres per hour. As the control for the spray bars is of a simple on/off type, controlled by an operator standing on top of the spray bar housing 3, the control valve 5 for the supply of compressed air to the choppers is controllable by the operator so as to vary the speed of operation of the choppers as required in order to obtain the requisite proportion of chopped fibreglass to binder in the final product. Whereas normally a top dressing would simply be applied separately shortly after use of the attachment, in some cases a hopper for supply of a top dressing will be mounted to follow the attachment directly for the depositing of top dressing thereonto prior to rolling.

In use of the device of the present invention in some cases it will be found that there is no need to operate the second spray bar, but that adequate coverage of the chopped fibreglass will be achieved simply due to the fibreglass sinking in the applied binder layer prior to the application of top dressing. However, in other cases, this may not be sufficient and in such cases the operator will also operate the rear spray bar in the housing 3 to apply a layer of binder to ensure coverage of all of the applied glass fibres.

Claims

1. An attachment for mounting to a vehicle for applying a surface dressing of tar and/or bituminous binder material reinforced with glass fibres, such a machine comprising an openbottomed spray bar housing for attachment to a vehicle, a spray bar mounted to said housing for spraying binder material from a plurality of nozzles placed longitudinally of the spray bar housing to extend transversely of movement of the vehicle when mounted thereon, means for controlling operation of the nozzles and a glass fibre distributor mounted to said spray bar housing and comprising an open-bottomed box mounted to extend the length of the spray bar housing and means for depositing cut glass fibres through said open bottom of the box to the surface of binder material previously sprayed from the spray bar nozzles during use of the attachment.

2. An attachment according to claim 1 , wherein a second spray bar housing and spray bar mounted thereto are secured to the distributor on the side thereof opposite to said first spray bar.

3. An attachment according to claim 2, wherein the second spray bar has fewer nozzles than the first spray bar.

4. An attachment according to claim 2 or 3, wherein the second spray bar is controllable independently of the first spray bar.

5. An attachment according to any preceding claim, wherein the distributor comprises a pneumatically powered chopper, means for supplying a tow of glass fibres to the chopper, means for supplying compressed air to the chopper for both powering the chopper and for spraying the chopped lengths of glass fibre therefrom, and means for controlling the rate of supply of compressed air.

6. An attachment according to claim 5, wherein two choppers are provided discharging into opposite ends of the distributor box.

7. An attachment according to claim 6, wherein the choppers are staggered in the direction of the vehicle.

8. An attachment according to any preceding claim, wherein means are provided for attaching a hopper for distribution of top dressing to the rear of the attachment.

9. An attachment for mounting to a vehicle for applying a surface dressing of tar and/or bituminous binder material reinforced with glass fibres to a surface, such attachment being constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.