GB2067522A - Heated transport containers - Google Patents

Abstract

A container for transport of heated material such as road making materials is provided with thermal insulation and heater means to maintain the temperature of the load for an extended period. The container may comprise a semi- trailer or wheel-less skip (20) capable of being moved by a heavy lorry and heated by electrical resistance heaters mounted within glass fibre insulated side panels (28) of the body, or a tipping trailer fitted with connection means for a tractor three point linkage and heated by propane gas fired burners. <IMAGE>

Description

SPECIFICATION Improvements relating to the transportation of heated materials This invention relates to the transportation of heated materials such as bituminous roadmaking materials for example.

Bituminous road-making materials are usually mixed at a supplier's depot and then transported by road in a tipper lorry to the delivery site, which may be a depot where the material is subdivided or may be a roadmaking site where the material is tipped directly into a road-making machine for laying.

Because the usability of bituminous roadmaking materials depends on weather conditions, and because there may be site delays due to the weather, delay in preceding operations, and organisational problems, the transport cost involved in supplying heated bituminous materials is greatly increased. A lorry arriving on a delivery site may be held waiting for a considerable time before its load can be used, resulting in the working capacity of both the driver and the lorry being under-utilised.

Simply tipping the contents from the lorry and leaving them on the site is not usually a satisfactory solution to this problem, since the material very rapidly cools and becomes unusable.

There is a temperature range within which each type of road-making material may properly be laid, and the more sophisticated modern wearing courses tend to require mixing and laying at higher temperatures than hitherto, which are governed by the relevant British Standards.

It is an object of the present invention to provide a transportation container which enables a heated material to be kept in a usable condition on site for a prolonged period.

According to the invention there is provided a container comprising a body having a load space within which a heated material may be loaded, the body being provided with heater means to heat the load space and the container being adapted to co-operate for transportation with a motive unit and being readily detachable therefrom at a delivery site.

In addition to the provision of heater means, the body may be thermally insulated, for example by the use of glass fibre.

In one form, the body comprises a base and a plurality of surrounding walls, the base and walls each having an inner panel defining part of the load space, heater means adjacent said inner panel, thermal insulation adjacent said heater means, and an outer cladding panel concealing the heater means and insulation.

The heater means may comprise one or more electrical resistance heaters. Where a plurality of heaters is used, these are wired in parallel to ensure that the entire heating system does not cut out in the event of a localised fault.

An electrical power connection may be provided for connection of an external electrical power supply, which may be derived from the mains or from a generator, preferably a threephase generator. Alternatively, an integral power supply may be provided, comprising an integral generator or battery.

For example, single phase electrical panel heaters can be used, wired in parallel so that, if one of the panels becomes defective and ceases to conduct, there will not be a total failure of the heating circuit. The single phase heaters may be connected in a "star" arrangement in which three single phase heaters are arranged to have a common terminal to which a neutral line is connected, of the heaters being supplied by one phase of the three phase supply. This arrangement has the advantage that, if the power supply becomes defective by loss of one phase, only one of the heaters loses its supply whilst the other two heaters continue at full power.

Alternatively, the heater means may comprise fuel burners, for example propane gas burners.

The container may comprise a tipping trailer adapted to be towed behind a conventional tractor by the three point linkage thereof.

Alternatively, the container may be a semitrailer having road wheels and being adapted to be connected for towing behind the motive unit.

Alternatively again, the container may be a wheelless skip which is adapted to be loaded onto and off a trans-porter.

The container may be provided with a rear door which may be a tipping tail gate.

Alternatively, or in addition, particularly where the container is a skip, it may have one or more side doors and preferably has a pair of centrally opening vertically pivoted doors, having a width sufficient to permit access by a mechanical handling machine to unload the contents.

A preferred embodiment of the invention comprises a skip adapted to be mounted for tipping movement and for on-off loading movement on a transporter motive unit.

In an alternative embodiment, the container may, be based on a standard freight container capable of being transported by lorry, train or ship.

The invention will now be described in more detail by reference to the accompanying drawings in which: Figure 1 is a side elevational view of a tipping trailer showing the placement of heating panels; Figure 2 is a diagrammatic side elevational view of a form of tippable skip embodying the invention, partly broken away; Figure 3 is a diagrammatic sectional view on the line 3-3 of Fig. 2; Figure 4 is a side-elevated view of a small scale tipping trailer embodying the invention.

Referring to Fig. 1 of the drawings, there is illustrated a first embodiment of the invention in the form of a tipping semi-trailer 10 which includes a chassis 11, rear road wheels 1 2 mounted on two rear axles 1 3 and foldable support legs 14 disposed towards the forward end of the trailer. However, the trailer could differ in constructional details, for example the number of axles, or by providing either manually or automatically-operated support legs.

The trailer includes a towing attachment 1 5 by which it can be hitched to a towing vehicle for transport of its contents by road. In this case, the support legs 14 will be folded up under or alongside the chassis 11 and the trailer 10 will be supported only by the rear road wheels 1 2 and by the towing attachment 1 5 secured to the towing vehicle.

A body 1 6 is mounted on the chassis 11 in such a way as to be capable of being tipped.

The body 1 6 comprises side walls 1 7, a front wall 1 8 and a rear openable door 1 9. The body is open at the top and has a base which may be flat or profiled so as to lie on or between the members of the chassis 11.

The body 1 6 is pivoted near its rear end in the region of the rear road wheels 1 2. The front wall 1 8 carries one or more brackets 20, the or each bracket being pivotally mounted to a hydraulic lifting arm 21. Thus, on operation of the hydraulic lifting arm or arms, the body 1 6 of the semi-trailer can be raised at the forward end and pivoted about its rearwardly disposed support in the region of the rear road wheels 12. The rear door may be opened to tip the contents of the trailer body as required.

The walls and possibly the floor of the trailer body 1 6 are provided with heater means which are visible in the broken-away section of the side wall 1 7. The heater means comprise heater panels 22 which are of elongate rectangular shape. The walls of the body are composite and comprise a framework of box-section metal struts 23, secured between main frame members 24. The inner face of each wall is panelled (not shown) with flat metal sheets, similar cladding 25 being used on the outer faces of the walls.

The heater panels 22 are arranged in close contact with the internal cladding of the body 1 6 although they are electrically insulated from the body. The panels themselves are single phase electrical resistance heating panels, which are wired up in parallel so that failure of one panel will not have the effect of shutting down the entire heating circuit.

A layer of glass fibre or similar insulation is packed between the heater panels 22 and the external cladding 25 to reduce the amount of heat lost through the outer cladding 25.

The trailer is provided with an electrical connection disposed beneath the rear crossmember 26 where it will not be disturbed either by the operation of the rear door 1 9 or by the operation of the hydraulic lifting arm or arms 21. The panels may be heated either by the supply of mains power or from a generator, typically a three phase generator. The heater elements of the panels are arranged so that, when a three phase generator is used, one phase is supplied to each of the single phase heater elements, which share a common neutral line. The heater elements are therefore arranged in a "star" formation which has the advantage that, if one phase of the electrical supply is disrupted, full power transmission to two of the three heaters still continues from the other phases of the supply and only one of the three elements cools down.

It is envisaged that the semi-trailer shown in Fig. 1 could be filled with a hot bituminous road making material at a supplier's depot and could then be transported by being towed behind a towing vehicle, to a delivery site.

The semi-trailer could then be unhitched from the towing vehicle and left on the delivery site, after first having been connected to a power supply from a generator. The heater panels 22 would then supply heat to the contents of the semi-trailer so as to keep the bituminous material in a condition in which it can be laid satisfactorily.

The towing vehicle could then return to the supplier's depot for another load or could be released for other purposes such as transporting aggregate or fillers. It would be possible, in the meantime, to fill another semi-trailer at the supply depot to await the return of the towing vehicle and, in this case, the heater panels could be connected up to the local mains power supply or to a generator so as to keep the contents of the semi-trailer hot while awaiting the towing vehicle.

To reduce heat losses by convection, a tightly fitting and preferably insulated tarpaulin cover could be used over the body 1 6 of the semi-trailer once this has been filled with the bituminous material.

In a typical application, a bituminous road making material will be prepared at a temperature of approximately 190 C and loaded into a tipping trailer as shown in Fig. 1. The power supply at 240 volts will give an estimated total electrical loading of 1 2 kilowatts which should be sufficient to maintain a typical load at a temperature of about 120 C at 7"C ambient temperature. Thus, the bituminous material can be kept at a temperature which is high enough to enable it to be laid satisfactorily even at the minimum ambient temperature normally acceptable for laying asphalt. The thickness of the glass fibre insulation layer should be about 60 millimetres.

So far as site operations are concerned, delivery of road making materials need not be confined strictly to the period immediately before they are due to be laid, thereby ena bling greater flexibility in working. All that is required is the provision of a sufficiently large generator or a sufficient number of generators for the maximum number of loads likely to be standing on the site at any given time. The tipping trailer illustrated in Fig. 1 has the advantage that the contents can be tipped directly into a road laying machine if required, through the rear door 1 9.

Fig. 2 of the drawings illustrates an alternative system for transportation of heated materials embodying the invention. Fig. 3 illustrates the layout of a typical heater panel, forming a section of Fig. 2 on the lines Ill-Ill.

However, Fig. 3 could equally well be a section of one of the panels 22 of the semitrailer 10 of Fig. 1.

The inner cladding 27 closely contacts the heater panel 22 which is eiectrically but not thermally insulated from it. Metal struts 23 forming part of the body structure can be seen in the drawing and the heater panel is illustrated in position between these struts 23.

A layer of glass fibre insulation 28 is provided externally of the heater panel 22 and completely fills the space between the metal struts 23 and an outer cladding panel 25.

Fig. 2 of the drawings illustrates a typical skip 29 capable of being mounted on a lorry 30 via a support frame 31. Rollers are provided towards the rear of the skip 29 cooperable with a roller track on the chassis of the lorry (not shown) to enable the skip 29 to be unloaded from the lorry. An hydraulic jack 32 is provided, operating on the support frame 31, to raise the skip 29 to the condition shown in Fig. 2, in which the contents can be tipped out through a top hung pivoted rear door 33 or, by lifting the support frame 31 to a greater extent, the entire skip 29 and its contents can be rolled off the lorry and deposited on the ground. In this case, of course, the rear door 33 is kept closed.

The skip 29 is provided with heater panels 22 in precisely the same manner as is described above in relation to the semi-trailer shown in Fig. 1. Part of the skip body is shown broken away to reveal the insulation 28. The heater panels 22 are between this insulation 28 and the inner cladding 27 as shown in more detail in the sectional view of Fig. 3.

The skip 29 can of course only be tipped when it is mounted on the lorry 30. This enables the contents to be tipped into a road laying machine for example. However, when a lorry carrying such a skip fill of material arrives on a site and the material is not to be used immediately, the skip 29 is deposited on the ground and connected to a power supply from a generator, as described in connection with the embodiment of Fig. 1. In order to unload the skip satisfactorily, a pair of side doors 34 are provided, having vertical hinges 35 and a suitable locking arrangement 36 to prevent the doors opening accidentally. The doors are made sufficiently wide to accept the forward end of a mechanical shovel which can therefore be moved into the opening created by the doors and used to unload the entire contents of the skip on site.

The rating and layout of the heaters are similar to those described in relation to the tipping trailer of Fig. 1 and the skip can also be provided with a tarpauiin cover as previously described, to reduce convection heat loss.

In a modification (not shown) the skips can be provided with locking means such that the skips can be stacked and mechanically handled in the same way as conventional freight containers, to enable them to be transported for long distances by rail or ship for example.

Whilst the invention has been described in relation to a skip or trailer body having an external power connection, it may be possible to provide sorne internal electrical power supply capable of heating the panels described above. Alternatively, heaters other than electrical heating panels can be envisaged for use in trailers or skips as described.

In a further embodiment, shown in Fig. 4 of the drawings, the container is in the form of a tipping trailer 40 having a chassis 41 provided with a pair of road wheels 42 mounted on an axle at one end and having means generally indicated at 43 for connection to the three point linkage of a tractor of conventional type. The trailer 40 has a generally rectangular body 44 within which a material to be kept hot can be inserted. The top of the trailer is closed by an insulated lid 45 which is hinged to the body 44 and assists in keeping the material warm.

Beneath the body 44 on the chassis there are provided propane gas burners 46 fed from a propane gas cylinder 47 mounted on the chassis.

The body 44 is arranged to pivot about a pivot point 48 behind the road wheels 42, by the action of the three point linkage of the tractor.

The walls of the body 44 and the lid are provided with thermal insulation in the form of glass fibre which may be mixed with wood chips, the walls themselves being of metal and comprising inner and outer panels somewhat as described above in the preceding embodiments.

The trailer can readiiy be coupled to the electrical and hydraulic supply of a conventional tractor and can be towed on the road in this condition. The propane gas burners can be operated to keep the material warm and usable for a prolonged period on site.

This embodiment of the invention may be preferred where relatively small quantities of material, for example of the order of five tonnes. Additionally, it will be appreciated that no external electrical power supply is needed for the maintaining of the material temperature since the trailer has its own propane cylinder and burners for this purpose.

Claims (22)

1. A transportation container for heated material comprising a body having a load space within which a heated material may be loaded, the body being provided with heater means to heat the load space and the container being adapted to co-operate for transportation with a motive unit and being readily detachable therefrom at a delivery site.

2. A container according to Claim 1 wherein the body is thermally insulated.

3. A container according to Claim 2 wherein the insulation includes glass fibre.

4. A container according to any preceding claim wherein the body comprises a base and a plurality of surrounding walls, the base and walls each having an inner panel defining part of the load space, heater means adjacent said inner panel, thermal insulation adjacent said heater means, and an outer cladding panel concealing the heater means and insulation.

5. A container according to any preceding claim wherein the heater means comprises one or more electrical resistance heaters.

6. A container according to Claim 5 wherein a plurality of heaters are provided, wired in parallel.

7. A container according to Claim 5 or Claim 6 wherein an electrical power connection is provided for connection of an external electrical power supply.

8. A container according to Claim 7 wherein the electrical power connection is adapted to connect to a standard electrical mains supply.

9. A container according to Claim 7 wherein the electrical power connection is adapted to connect to a three-phase generator.

10. A container according to Claim 9 wherein the electrical heaters are single-phase panel heaters and are connected in groups of three in a "star" arrangement wherein the three single-phase heaters have a common neutral terminal, each of the heaters being supplied by one phase of the three-phase supply.

11. A container according to Claim 5 or Claim 6 wherein an integral power supply is provided comprising an integral electrical generator or battery.

1 2. A container according to any one of Claims 1 to 3 wherein the heater means comprise fuel burners.

1 3. A container according to Claim 1 2 wherein the fuel burners comprise propane gas burners.

14. A container according to any preceding claim and comprising a tipping trailer adapted to be towed behind a conventional tractor by the three point linkage thereof.

1 5. A container according to any one of Claims 1 to 1 3 and comprising a semi-trailer having road wheels and being adapted to be connected for towing behind the motive unit.

1 6. A container according to any one of Claims 1 to 1 3 and comprising a wheel-less skip adapted to be loaded onto and off a trans-porter.

1 7. A container according to any preceding claim and provided with a rear door comprising a tipping tail gate.

1 8. A container according to any one of Claims 1 5 to 1 7 and having one or more side doors.

1 9. A container according to Claim 1 8 wherein the side doors comprise a pair of centrally opening vertically pivoted doors, having a width sufficient to permit access by a mechanical handling machine to unload the contents.

20. A Container comprising a semi-trailer substantially as hereinbefore described with reference to and as illustrated in Fig. 1 of the accompanying drawings.

21. A container comprising a wheel-less skip substantially as hereinbefore described with reference to and as illustrated in Figs. 2 and 3 of the accompanying drawings.

22. A container comprising a tipping trailer substantially as hereinbefore described with reference to and as illustrated in Fig. 4 of the accompanying drawings.