GB2613952A

GB2613952A - Bitumen spreader vehicle and method of operating

Info

Publication number: GB2613952A
Application number: GB2216698.7A
Authority: GB
Inventors: Zahariev Kamburov Sasho
Original assignee: Spray Tanker Services Ltd
Current assignee: Spray Tanker Services Ltd
Priority date: 2022-11-09
Filing date: 2022-11-09
Publication date: 2023-06-21
Anticipated expiration: 2042-11-09
Also published as: GB2613952B; GB202216698D0

Abstract

A bitumen spreader vehicle 10 comprises an internal combustion engine having a power take-off 32 for powering a generator 34. A bitumen storage vessel 24 comprises a heating element 42 powered by the generator. The spreader also includes a bitumen spray outlet 30 for dispensing bitumen for road sealing. The generator is powered during an active period of the engine to heat the bitumen to a flowable temperature for dispensing. The spreader may further include an emulsified bitumen storage vessel 18 and spray outlet 20. The storage vessel may comprise a tank and the heating element may be positioned in a thermal oil chamber surrounding the tank. An oil pipe connected to the oil chamber may be positioned in the tank. The heating element may be an immersion heater. A secondary heating system such as a burner or battery powered electric heater may be provided as a failsafe. The exhaust outlet of the spreader may be in thermal communication with the storage vessel. A method of operating a spreader includes the step of activating an internal combustion engine to operate a generator and power a heating element in a bitumen storage vessel.

Description

Bitumen Spreader Vehicle and Method of Operating The present invention relates to a bitumen spreader vehicle, particularly but not necessarily exclusively a joint-sprayer or joint-sealer vehicle suitable for bitumen application of a road during maintenance. The invention further relates to a method of operating such a bitumen spreader vehicle, as well as a method of retrofitting a bitumen spreader vehicle to reduce fuel consumption.

When a new road or new road surface is laid, a layer of bituminous substance is necessary to meet regulatory requirements, such as British Standards BS594987. This is known as tack coating or bond coating, and ensures that the overlying asphalt or tarmac layers adhere correctly. This is typically performed by spraying bitumen onto the surface to be laid, known as the bond coat, and then sealing the joints according to the same standards. Typically, the bond coat is an emulsified bitumen for ease of spraying, whereas the edge material is traditionally coated with a standard bitumen composition, or polymer-modified variant.

Bitumen spreader vehicles either have only a spray bar for applying the main bitumen coating, or also include a joint sprayer. Such a bitumen spreader vehicle is itself commonly referred to as a combi-sprayer, joint-sprayer, or joint-sealer vehicle.

In combi-sprayer vehicles, there are two separate bitumen tanks; one comprising an emulsified bitumen which is sprayed from the emulsion spray bar; and one comprising hot pitch, which may be pure bitumen, or modified bitumen such as polymer-modified bitumen, to be sprayed from the joint sprayer. Bitumen has a lower flowable temperature when emulsified, and therefore can be used more easily. Typically, it will be applied at temperatures of between 65°C and 90°C.

On the other hand, 40/60 penetration grade bitumen starts to melt at 50°C, but does not 25 exhibit viable flow properties until it reaches a working temperature of usually 170°C to 180°C. This poses several challenges for combi-sprayer vehicles.

Firstly, a high bitumen temperature must be maintained in the run-up to any bitumen laying operation. It can take several hours to heat the bitumen to the requisite flow temperature. Since diesel burners are commonly used for this purpose, this wastes a 30 large amount of energy.

Furthermore, the joint sprayers are located remote from the bitumen tank itself, and therefore there is a significant risk of blockage to the joint sprayer pipes, if the bitumen is cooled before application.

It is an object of the present invention to improve the operation of combi-sprayer vehicles.

According to a first aspect of the invention, there is provided a bitumen spreader vehicle comprising: an internal combustion engine having a power take-off associated therewith; a generator powered from the power take-off; a bitumen storage vessel having a heating element associated therewith, the heating element being powered by the generator; and a bitumen spray outlet for dispensing bitumen for road sealing; wherein the generator is powered during an active period of the internal combustion engine, such that the heating element is in constant operation during the said active period to heat bitumen in the bitumen storage vessel to a flowable temperature for dispensing via the bitumen spray outlet.

The present invention seeks to reduce the environmental impact of road construction or maintenance operations. At present, diesel burners consume vast amounts of fuel to heat hot pitch for joint spraying. The changes made to the bitumen spreader vehicle here utilise the kinetic energy of the already operational internal combustion engine to provide electrical energy to the heating elements of the bitumen storage vessel. Since the bitumen spreader vehicle is typically required to have its engine running for many hours prior to a spraying operation, this modification effectively has no consequential deleterious effect on existing fuel consumption, whilst eliminating the need for a separate diesel burner. Fuel consumption can therefore be significantly reduced.

The bitumen spreader vehicle may further comprise a bitumen/emulsion storage vessel having an emulsified bitumen spray outlet for dispensing an emulsified bitumen mixture 25 for road sealing.

The present invention will typically be applied to a joint-sprayer vehicle, which allows for the edges of the road surface to be sprayed by a single vehicle, reducing the requirement for manual hot pitch application.

Optionally, the bitumen storage vessel may comprise a bitumen tank and a thermal oil chamber around and in thermal communication with the bitumen tank, the heating element being positioned in the thermal oil chamber.

Indirect heating of the bitumen via an oil jacket provides a safer means of thermal transfer 5 than by direct application of heat to the bitumen tank, since there is no risk of ignition, and the heat capacity of the oil is lower than that of the bitumen.

There may preferably be a thermally conductive oil pipe in fluid communication with the thermal oil chamber and which is positioned in the bitumen tank.

By introducing a thermally conductive pipe into the bitumen tank itself, then thermal 10 transfer efficiency can be drastically increased since the centre of the bitumen tank is otherwise difficult to thermally penetrate.

Advantageously, the thermally conductive oil pipe may be circuitous, serpentine, or undulating.

The shaping of the thermally conductive oil pipe can be made so as to optimise or 15 otherwise greatly increase the surface are in contact with the bitumen, improving the rate of thermal transfer therebetween.

The bitumen spreader vehicle may further comprise an oil pump associated with the thermally conductive oil pipe.

To improve heating efficiency within the bitumen storage tank, effective circulation 20 through the thermally conductive oil pipe is desirable, particularly for pipes having small internal diameters which can lose heat quickly.

Optionally, the heating element may be an immersion heater.

By providing the heating element as an immersion heater, the oil chamber type of heating process can be utilised to a most advantageous degree.

In one embodiment of the invention, there may further comprise a mixer in the bitumen storage vessel for agitating the bitumen.

Agitation of the bitumen can increase the speed of thermal transfer, reducing the engine-active duration required.

The bitumen spreader vehicle may further comprise a secondary heating system.

Providing supplementary heating means can allow for increased heating efficiency in 5 some urgent circumstances, as well as providing fallback options in the event of system failure such as loss of power.

Optionally, the bitumen storage vessel may comprise at least one insulated wall.

Improved fuel efficiency can be achieved by insulation of the bitumen storage vessel, reducing the operational time for the generator.

In one preferred embodiment, two said bitumen spray outlets are provided on either side of the bitumen spreader vehicle.

The provision of paired joint sprayers on the side of the vehicle allows for edge sealing to occur on both sides simultaneously, reducing the time taken to perform the spraying action, and potentially reducing the risk of clogging of the joint sprayers.

There may optionally further comprise a connection conduit between the two bitumen spray outlets to form a bitumen circuit from the bitumen storage vessel.

The presence of a cyclical system allows for return of unspent bitumen to the bitumen storage vessel for re-thermalisation, reducing the risk of clogging of the pipes themselves.

The bitumen spreader vehicle may further comprise a bitumen pump for pumping 20 bitumen around the bitumen circuit.

Pumping of the bitumen may be required to not only return the bitumen to the bitumen storage vessel for reheating, but also to provide sufficient back pressure to the joint sprayers themselves.

Additionally, or alternatively, there may be an oil conduit system in thermal 25 communication with the connection conduit.

The connection conduit is the most exposed part of the bitumen return path, and therefore it is important for the thermal oil to be able to heat the connection conduit to reduce the risk of clogging.

Preferably, the oil conduit system may run in parallel with the connection conduit.

A complete complementary heating system running alongside the bitumen pathway will further reduce the likelihood of clogging.

The bitumen spreader vehicle may further comprise an oil circuit pump for pumping oil around the oil conduit system.

Given the risk of cooling via environmental effects, effective circulation of the thermal oil 10 is highly desirable for the oil conduit system, and a pump achieves this readily.

The vehicle may further comprise a hydraulic pump connected to the power take-off, the generator being a hydraulic generator powered by the hydraulic pump.

Hydraulic powering via a power take-off is likely the simplest means of converting the kinetic energy of the power take-off into electrical energy.

The bitumen spreader vehicle may further comprise a hydraulic control system mounted in a cab thereof.

Comfortable operation of the systems of the vehicle can be provided from the cab, which may also improve operator safety.

The bitumen spreader vehicle may further comprising a temperature display for the 20 bitumen storage vessel.

A temperature display, preferably in a cab of the vehicle, can provide diagnostic functionality, particularly if both the oil and bitumen temperatures are displayed.

Preferably, there may be an exhaust outlet of the internal combustion engine is in thermal communication with the bitumen storage vessel.

Since exhaust fumes of the internal combustion engine are hot, they can be diverted into thermal exchange with the bitumen storage vessel by redirection of the fumes through thermally conductive ducting thereto.

Optionally, there may further comprise a supplementary catalytic converter provided in 5 thermal communication with the bitumen storage vessel.

A supplementary catalytic converter can be installed in communication with the existing exhaust outlet of the internal combustion engine. Since the catalytic converter generates vast amounts of heat, thermal transfer to the bitumen storage vessel further reduces energy consumption of the vehicle, whilst also potentially reducing the pollution generated by the vehicle as well.

According to a second aspect of the invention, there is provided a method of operating a bitumen spreader vehicle in accordance with the first aspect of the invention, the method comprising the step of: activating the internal combustion engine of the bitumen spreader vehicle to operate the generator and provide power to the heating element for heating bitumen in the bitumen storage vessel.

By using a vehicle as previously described, surface dressing operations can be performed with reduced fuel consumption.

According to a third aspect of the invention, there is provided a method of retrofitting a bitumen spreader vehicle to reduce fuel consumption, the method comprising the steps of: installing a generator to a power take-off of an internal combustion engine of the bitumen spreader vehicle; and connecting the generator to a heating element associated with a bitumen storage vessel, such that the heating element is in constant operation during an active period of the internal combustion engine to heat bitumen in the bitumen storage vessel to a flowable temperature for dispensing via the bitumen spray outlet.

Given that most internal combustion engines have the capability to incorporate a power take-off to drive apparatus, the present invention is eminently retrofittable to existing vehicles.

The method preferably may further comprise the step of removing a pre-existing diesel burner from the bitumen spreader vehicle.

According to a fourth aspect of the invention, there is provided a bitumen spreader vehicle comprising: an internal combustion engine having a power take-off associated therewith; a bitumen storage vessel; a bitumen spray outlet for dispensing bitumen for road sealing; and an exhaust outlet of the internal combustion engine or supplementary catalytic converter in thermal communication with the bitumen storage vessel to provide thermal energy to bitumen therein and bringing said bitumen to a flowable temperature for dispensing via the bitumen spray outlet.

Routing of exhaust fumes, or inserting of a catalytic converter in or associated with the bitumen storage vessel, provides an additional source of heat which is already present 10 and generated by the vehicle, reducing overall fuel consumption for the heating of the bitumen.

Given that the generator provides power to the heating elements, the diesel burner typically used will become redundant and can be removed.

The invention will now be more particularly described, by way of example only, with 15 reference to the accompanying drawings, in which: Figure 1 shows a pictorial representation from the side of one embodiment of a bitumen spreader vehicle in accordance with the first aspect of the invention; Figure 2 shows a pictorial representation in cross-section of the bitumen storage vessel of the bitumen spreader vehicle of Figure 1; Figure 3 shows a pictorial representation in cross-section of a second embodiment of a bitumen storage vessel for a bitumen spreader vehicle in accordance with the first aspect of the invention; and Figure 4 shows a plan representation of the bitumen spreader vehicle of Figure 1, with the internals of the bitumen storage vessel indicated for clarity.

Referring to Figure 1, there is illustrated a bitumen spreader vehicle, referenced globally at 10, which is suitable for performing road sealing applications as defined above. The road surfacing vehicle 10 comprises a main chassis 12 having an operator cab 14 at a front end thereof.

At a rear end of the bitumen spreader vehicle 10 there is an emulsion spray bar 16 or head which spans the width of the main chassis 12. It is preferred that the emulsion spray bar 16 slightly overhang the main chassis 12 so as to cover as large an area as possible during use. The emulsion spray bar 16 is connected to a large emulsified bitumen storage vessel 18, with the emulsion spray bar 16 having at least one emulsified bitumen spray outlet 20 for applying the emulsified bitumen mix to a road surface. The emulsified bitumen storage vessel 18 is also located towards a rear end of the main chassis 12.

The emulsified bitumen storage vessel 18 will typically be connected to the emulsion spray bar 16 by a hose 22 or similar flow manifold through which the emulsified bitumen 10 mix can flow.

A bitumen storage vessel 24 is provided on the main chassis 12 in which pure bitumen can be stored. This is connected via a hose 26 to a joint sprayer 28 which hangs off one or other side of the bitumen spreader vehicle 10. Typically, both left and right joint sprayers 28 will be provided, as can be seen from Figure 4, each having bitumen spray outlets 30. Of course, it is possible to provide a vehicle having only a single joint sprayer on one side.

An internal combustion engine is provided for the bitumen spreader vehicle 10, typically being a diesel combustion engine. This would usually be mounted under the cab 14 or otherwise mounted to the main chassis 12. The internal combustion engine has a power 20 take-off 32 via which hydraulic or other energy transfer operations can be performed.

It is possible to therefore mount a generator 34, such as a hydraulic generator, to the main chassis 12 of the bitumen spreader vehicle 10, typically in the undercarriage 36, via which electricity can be generated from the power take-off 32. This is something which can therefore be retrofitted to existing vehicles as necessary, or could be included as part of newly manufactured bitumen spreader vehicles 10.

It will be appreciated that the power take-off 32 may also drive a hydraulic pump, which can be used to operate many of the sub-systems of the bitumen spreader vehicle 10, such as control of the joint sprayer 28 and spray bar 16.

The generator 34 is then used to supply electricity to the bitumen storage vessel 24, for the purpose of heating. Equally, the generator 34 can provide the necessary energy to heat the emulsified bitumen in the emulsified bitumen storage vessel 18.

Crucially, the generator 34 is operational during an operational period of the bitumen 5 spreader vehicle 10. As such, the bitumen is being brought up to temperature automatically, without the need to provide a separate diesel burner. Generally, a bitumen spreader vehicle 10 will be active for long periods of time during transit to site, as well as whilst waiting for initial works to be completed. As such, the internal combustion engine is almost always left running. The present invention therefore utilises the kinetic energy 10 of the internal combustion engine, via the power take-off 32, to generate the heat for the bitumen storage vessel 24.

Figure 2 shows the internals of the bitumen storage vessel 24. There is a bitumen tank 38 in the centre of the bitumen storage vessel 24, into which bitumen can be introduced, typically via a top hatch. Around the bitumen tank 38 is a thermal oil chamber 40 which is fluidly isolated from the bitumen tank 38, but in thermal contact therewith. The thermal oil chamber 40 is filled with thermal oil.

At least one heating element 42 is provided in the thermal oil chamber 40, preferably in the form of an immersion heater, and the heating elements 42 are powered directly by the generator 34. Heating of the thermal oil thus heats the bitumen in the bitumen tank 38. There will preferably be thermostatic control of the heating elements 42, due to the lag of conduction between the thermal oil and the bitumen. In a preferred control arrangement of a thermal control unit, there will be a thermostat monitoring the oil temperature, and a thermostat monitoring the bitumen temperature. The heating elements 42 will be deactivated when the oil temperature reaches 200°C, or when the bitumen reaches 180°C, and will be activated when the oil temperature drops below 180°C.

In the bitumen storage vessel 24 of the present embodiment, there is also a thermally conductive oil pipe 44 which is in fluid communication with the thermal oil chamber 40, but which extends into the bitumen tank 38. Preferably, the thermally conductive oil pipe 44 is shaped to have a circuitous, serpentine, or undulating, thereby increasing the surface area in contact with the bitumen in the bitumen tank 38, improving thermal conduction therebetween. An oil pump 46 may be provided associated with the thermally conductive oil pipe 44 to draw heated oil therethrough. The oil pump 46 may be powered by a hydraulic pump powered directly by the power take-off 32, or may be indirectly powered by a separate hydraulic pump, or by the generator 34. Equally, electric pumps or motors could be used.

An alternative embodiment of bitumen storage vessel 24' is shown in Figure 3. Instead of a thermally conductive oil pipe in the bitumen tank 38', there is a mixer 48', which may also be driven indirectly by the power take-off. This agitates the bitumen, rather than increasing the surface area in contact with the thermal oil. Thermal conduction will only occur at the interface between the bitumen tank 38' and the thermal oil chamber 40', the heating elements 42' still heating only the thermal oil directly. The mixer 48' would typically only be active when the bitumen spreader vehicle 10 is not in motion, which may reduce its utility compared with the previous embodiment.

Figure 4 shows more detail regarding the whole system. The bitumen storage vessel 24 is heated by power from the generator 34, and bitumen flows through the hoses 26 to the joint sprayers 28. This is operated cyclically, with bitumen flowing first to one joint sprayer 28, via a connecting conduit 50, and to the other joint sprayer 28. This represents a risk, since the hoses 26 and connecting conduit 50 can cool quickly, solidifying the bitumen and causing blockages. A dedicated bitumen pump 52 may be provided to ensure that flow occurs in the correct direction through the bitumen hoses 26 and connecting conduit 50.

In order to maintain back pressure to a joint sprayer 28 it is preferred that the return hose 26 be cut-off via a control valve. A control valve would therefore be provided for the joint sprayers 28 in the present invention.

To mitigate this issue, a counterpart oil conduit system 54 is provided which runs in parallel with the bitumen hoses 26 and connecting conduit 50, for instance, by physically, but not fluidly, conjoining the oil conduit system 54 to the bitumen hoses 26 and connecting conduit 50. A dedicated pump 56 may be provided to ensure a good thermal flow around the oil conduit system 54.

In use, a bitumen spreader vehicle would typically be turned on to warm up the internal combustion engine, in order to ensure that electrical functions do not drain the battery.

In the present invention, however, as soon as the internal combustion engine is activated, the hydraulic generator is operational. This might be several hours before the intended use time.

Whilst a diesel burner is obviated for the present invention, it will be apparent that issues with the hydraulic systems could make a secondary heating system desirable as a failsafe. This could, of course, be a diesel or other type of burner, such as gas, propane, or similar fuels, but equally could be an electric heating system. This electric heating system could be powered by the main battery of the bitumen spreader vehicle, and thus may be more appropriate for electric vehicle technology.

Further heating of the bitumen storage vessel could also be achieved by routing hot exhaust fumes, through a thermally-conductive ducting, from the exhaust of the internal combustion engine, through the bitumen storage vessel. Typically this would be a conduit through the thermal oil chamber, subsequent to the catalytic converter. Since the exhaust fumes are hot, this will result in additional heating without any additional energy spend.

Additionally, or alternatively, a supplementary catalytic converter could be positioned in thermal communication with the bitumen storage vessel, typically in the thermal oil chamber, to achieve the same effect. Since the catalytic converter is hot, the additional heat generated will raise the temperature of the thermal oil further. This also has the added benefit of further cleaning the exhaust fumes, reducing the polluting effect of the output gas.

Whilst a single walled bitumen storage vessel is shown in the pictorial images, it will be apparent that insulation is highly desirable, and indeed, double-layered insulation of the bitumen storage vessel is preferred.

It is intended that the control operations of the bitumen spreader vehicle are all operated from the cab. As such, the hydraulic control panel may be positioned in the cab, including at least controls for the joint sprayers. Furthermore, temperature displays for the bitumen storage vessel and/or emulsified bitumen storage vessel may also be present in the cab. For the bitumen storage vessel, it is preferred that the temperature display show both the bitumen temperature and the oil temperature.

It is therefore possible to provide a bitumen spreader vehicle which has a reduced fuel consumption and therefore improved environmental criteria by utilising the power takeoff from the internal combustion engine to generate electricity via a generator. The electricity can then be used to heat bitumen in a bitumen storage vessel for the purpose of applying to road surfaces during a surface dressing application via a joint sprayer thereof.

The words 'comprises/comprising' and the words 'having/including' when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps, or components, but do not preclude the presence or addition 10 of one or more other features, integers, steps, components, or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The embodiments described above are provided by way of examples only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined herein.

Claims

Claims 1. A bitumen spreader vehicle comprising: an internal combustion engine having a power take-off associated therewith; a generator powered from the power take-off; a bitumen storage vessel having a heating element associated therewith, the heating element being powered by the generator; and a bitumen spray outlet for dispensing bitumen for road sealing; wherein the generator is powered during an active period of the internal combustion engine, such that the heating element is in constant operation during the said active period to heat bitumen in the bitumen storage vessel to a flowable temperature for dispensing via the bitumen spray outlet.
2 A bitumen spreader vehicle as claimed in claim 1, further comprising an emulsified bitumen storage vessel having an emulsified bitumen spray outlet for dispensing an emulsified bitumen mixture for road sealing.
3 A bitumen spreader vehicle as claimed in claim 1 or claim 2, wherein the bitumen storage vessel comprises a bitumen tank and a thermal oil chamber around and in thermal communication with the bitumen tank, the heating element being positioned in the thermal oil chamber.
4 A bitumen spreader vehicle as claimed in claim 3, further comprising a thermally conductive oil pipe in fluid communication with the thermal oil chamber and which is positioned in the bitumen tank.
5. A bitumen spreader vehicle as claimed in claim 4, wherein the thermally conductive oil pipe is circuitous, serpentine, or undulating.
6. A bitumen spreader vehicle as claimed in claim 4 or claim 5, further comprising an oil pump associated with the thermally conductive oil pipe.
7. A bitumen spreader vehicle as claimed in any one of the preceding claims, wherein the heating element is an immersion heater.
8. A bitumen spreader vehicle as claimed in any one of the preceding claims, further comprising a mixer in the bitumen storage vessel for agitating the bitumen.
9. A bitumen spreader vehicle as claimed in any one of the preceding claims, further comprising a secondary heating system.
10. A bitumen spreader vehicle as claimed in any one of the preceding claims, wherein the bitumen storage vessel comprises at least one insulated wall.
11. A bitumen spreader vehicle as claimed in any one of the preceding claims, wherein two said bitumen spray outlets are provided on either side of the bitumen spreader vehicle
12.A bitumen spreader vehicle as claimed in claim 11, further comprising a connection conduit between the two bitumen spray outlets to form a bitumen circuit from the bitumen storage vessel.
13. A bitumen spreader vehicle as claimed in claim 12, further comprising a bitumen pump for pumping bitumen around the bitumen circuit.
14. A bitumen spreader vehicle as claimed in claim 12 or claim 13, further comprising an oil conduit system in thermal communication with the connection conduit.
15. A bitumen spreader vehicle as claimed in claim 14, wherein the oil conduit system runs in parallel with the connection conduit.
16. A bitumen spreader vehicle as claimed in claim 14 or claim 15, further comprising an oil circuit pump for pumping oil around the oil conduit system.
17. A bitumen spreader vehicle as claimed in any one of the preceding claims, further comprising a hydraulic pump connected to the power take-off, the generator being a hydraulic generator powered by the hydraulic pump.
18. A bitumen spreader vehicle as claimed in any one of the preceding claims, further comprising a hydraulic control system mounted in a cab thereof.
19. A bitumen spreader vehicle as claimed in any one of the preceding claims, further comprising a temperature display for the bitumen storage vessel.
20. A bitumen spreader vehicle as claimed in any one of the preceding claims, wherein an exhaust outlet of the internal combustion engine is in thermal communication with the bitumen storage vessel.
21. A bitumen spreader vehicle as claimed in any one of the preceding claims, further comprising a supplementary catalytic converter provided in thermal communication with the bitumen storage vessel.
22. A method of operating a bitumen spreader vehicle as claimed in any one of the preceding claims, the method comprising the step of: activating the internal combustion engine of the bitumen spreader vehicle to operate the generator and provide power to the heating element for heating bitumen in the bitumen storage vessel.
23. A method of retrofitting a bitumen spreader vehicle to reduce fuel consumption, the method comprising the steps of: installing a generator to a power take-off of an internal combustion engine of the bitumen spreader vehicle; and connecting the generator to a heating element associated with a bitumen storage vessel, such that the heating element is in constant operation during an active period of the internal combustion engine to heat bitumen in the bitumen storage vessel to a flowable temperature for dispensing via the bitumen spray outlet.
24. A method as claimed in claim 23, further comprising the step of removing a preexisting diesel burner from the bitumen spreader vehicle.