FR2475633A1 - Truck mounted hot line pavement striping system - has heat recovered from IC engine oil system by internal piping to warm liq. paint - Google Patents

Abstract

The heating system is for liquid in a truck mounted hot line pavement striping system with a paint storage tank and spray guns. The heating system includes a conduit from the i.c. engine of the truck leading to a series of smaller conduits passing through the thermal oil bath, as the sole heat source for heating the oil bath. The pipe then exhausts to the atmosphere, the inner walls of the tubes having sufficient heat exchanging surface and of sufficient number to conduct sufficient heat from the exhaust gases through the conduit wall to the oil bath to heat the thermal oil. The oil surrounds tubes within the bath which contain the paint to be sprayed "hot" from the paint guns. A heat by-pass from the engine can circumvent the heating system.

Description

The invention relates to a heating device using the exhaust gases from internal combustion engines.

 The heat conveyed by the exhaust gases from internal combustion engines constitutes an unused energy source which is not currently used as a thermal source intended for heating loads transported for example by trucks. Since the heat of the exhaust gases is currently practically lost, its use would be beneficial, while eliminating the need for auxiliary equipment carried by the vehicle. A possibility of use would be for example the heating of perishable foodstuffs transported by the vehicle. Another possibility would be heating with paint transported in cha @ @ sée mont @@ marking devices on trucks.

Currently, such a line marking device on a road surface mounted on a truck, uses paint stored at ambient temperature in pressure storage tanks and brings, from these tanks, spray guns, in order to apply it. on the delta pavement areas which must be marked with lines.

@ unfortunately, the heating period is quite long and, during drying, it is necessary to provide protection to prevent spreading and imprints caused by vehicles traveling on the road. To allow the paint to dry, marking cones are placed after application of this paint, then picked up by additional workers, and transported in a separate truck following, at a determined distance, the marker truck.

n because of the drawbacks of the aforementioned device, a more sophisticated device for hot painting has been developed.

In this device, the heated paint from the storage tank hot feeds the spray guns. After application, the "hot" paint dries in a few seconds.

although all recourse to marking cones is eliminated, an additional factor relating to the cost of the operation is brought into play, namely the cost entailed by heating the paint.

Although several methods of heating the paint have already been proposed, none have been satisfactory from the point of view of cost and / or yield. In particular, such a method of heating the paint requires the use of a reheater supplied with diesel oil, of sufficient capacity to bring water to a given temperature (below boiling), this water in turn heating the paint @ at a temperature between about 82 C and @@ C. However, heating with diesel requires the use of separate tanks, mounted on the truck, for the storage of diesel, which which entails additional costs.In addition, the heat source used is an external source, namely, diesel.

 In addition, the use of water limits the amount of heat that should be transferred to the paint.

The object of the invention is therefore to provide a heating device using the exhaust gases of an internal combustion engine, used in the above-mentioned application.

Other objects of the invention will emerge from the following definition of the invention and from the detailed description of its preferred embodiments.

The subject of the invention is a heating device intended for heating a material by means of the exhaust gases coming from an internal combustion engine, this device comprising a duct coming from the internal combustion engine and leading to a series of small conduits for the passage of heated exhaust gases, the conduits being immersed in and passing through an oil bath and then being discharged to the atmosphere, the interior walls of these conduits having an exchange surface sufficient thermal and the conduits being in sufficient number to transmit a sufficient quantity of heat from the exhaust gases, through the walls of these conduits, to the oil bath, in order to heat the latter, said bath surrounding the material intended to be heated, a bypass control being designed to prevent the exhaust gases containing the heat from circulating through the small conu @@ ts.

Preferably, the bath is a thermal oil bath.

Also preferably, the material to be heated is contained in a tube passing through the oil bath. Also, the small conduits pass through a lower part of the bath, so that the heated product rises and is replaced by colder ash oil, thus creating a convection current inside the ban.

 The accompanying drawing shows schematically and by way of example, a preferred embodiment of the subject of the invention.

On this drawing:
Figure 1 shows a truck according to a preferred embodiment of the invention;
Figure 2 is a schematic view of the hot painting device, according to the preferred embodiment of the invention;
Figure 3 is a view, on an enlarged scale, of the components of the device shown in Figure 2, used to heat the paint, in accordance with the preferred embodiment.

 Referring to Figures 1,2 and 3, there is shown a camian with tilting cabin, brand "Ford C-900", 10, having a cabin 12, an internal combustion engine 14 of 7818 cm3, and a trailer 16 on which are mounted a compressor 18, of the "Hercules" brand, with an internal combustion engine 20 with 4 cylinders, paint storage tanks 22 and 24; the paint heating device, generally designated by 26, itself comprising a) a duct 28 connected to the motors 14 and 20 by bypass valves 30 and 32 and outlets, respectively 34 and 36, intended for collect the exhaust gases from the engines; b) an oil tank 38, in which the oil filling this tank with sound is heated, this oil tank 38 comprising a chamber 40 d1 - intake of exhaust gases in direct communication with the conduit 28, and a series of small tubes 42 arranged parallel to each other, at the bottom 59 of the reservoir 38, leading to the outlet 44; c-) heat exchangers 46 connected to the oil tank 38 by conduits 48 and 50, conduits 52 starting from the paint storage tanks 22 and 24 to lead to serpentine streamers 54, in which the paint is heated, and outlet conduits 56 leaving the coils 54 to lead to high pressure spray guns 58 of the "Graco" brand; as well as adjustment devices 60 provided on the control console 62 in order to adjust the painting device.

 To heat the paint to the desired temperature of 940C and to maintain it at this temperature, the exhaust gases, of temperature higher than 2600C, coming from the engines of the truck "C-900" and from the compressor "Hercules", are brought to through bypass valves 30 and 52 controlled by a switch 64 (see Figure 1), and ducts of 50.8 mm and 101.6 mm, respectively- and 34 and 56 (instead of exiting through the exhaust pipes, 66 and 68 respectively, fitted with exhaust pipes 70). the gases are then mixed in a conduit 28 of 152.4 mm, so that no increase in pressure occurs, circulate in the chamber 40 then through 56 steel tubes 42 of 38.10 mm in diameter and 1.524 in in length, crossing the bottom 39 to the tank 38, the walls of the tubes representing a total heat conductive surface of 2.418 m2. After passing through the tubes 42, the exhaust gases are evacuated from the device through the conduit 44. although no insulation is shown in the drawing, each of the conduits 34, 36 and 28, the branches 30 and 32 and the reservoir 38 are all properly insulated to reduce heat loss.

 The heat reaching the tubes 42 and transmitted by the walls of the latter, heats the thermal oil in the reservoir 38 adjacent to these tubes, so that the oil tends to rise.

The internal upper part 72 of the reservoir 38 is divided into 3 sections, by means of curved fins 74 oriented vertically, welded at 73 to the extreme lateral walls of the reservoir 38. In this way, the heated oil rising between an extreme wall, substantially parallel to the fins 74 and one of these fins, circulates above the fin and falls back into the space between said fins 74, while the heated oil rising between the fins 74 is withdrawn into the tube 48, at means of the pump 76, thus creating a convection current in the tank 38. The air outlet 78 allows air to be admitted or escaped during variations in the volume of oil in the tank 38 following the heating of the The heated oil is then sent to the top of one or both heat exchangers 46, by means of the bypass valves 80, as required when the oil temperature indicated by the thermometers 82 is to be lowered. When the oil cools, it descends to the bottom of the heat exchanger 46, from where it is brought back, by tubes 84, into the return duct 50, then into the volume of the reservoir 38 adjacent to the tubes 42 where it heats up and goes up.

 Since the oil in the vicinity of the top of the heat exchangers is the hottest, the paint to be heated is pumped from one of the tanks 22 or 24, or both, by the conduits 52, to the coils 54 in the heat exchangers 46. As a result, the paint is heated when it rises in the coils, and it is brought to its maximum temperature before reaching the lower part 86, from which it is brought, by the tube 56, by means of pumps 57 of the "Graco 207567 King" brand and of "Greer 'accumulators, 59 with pistols 58, through the bypass valves 88, with a view to being sprayed, or even recycled through the conduit 90 and the bypass valves 92 and the conduits 52, through the painting device, in order to prevent the deposition of the paint in this device, and consequently, the hardening thereof inside Again, because heat loss has to be reduced, all of the components ts are isolated to reduce these losses.

In order to carry out the cleaning of the painting device or the loading of the paint reservoirs 22 and 24, identical devices 92 are provided on the conduits 52, only one of them being shown in FIG. 2. Each device 92 comprises an inlet 94 connected to the duct 52 by a bypass 96, a loading pump 95 and ball valves 981, 9811, 98III and a ball valve 98IV arranged in the duct 52. To clean the device, the valve 98IV on the duct 52 and the valve 98III are closed to the conduit, the valves 98I and 98II are open to the device, and toluene, loaded into the device by means of the pump 95, circulates through the conduit 56, the coil 54.1a lower part 86 , the valves 88, the return duct 90 and is discharged through the inlet 94. To carry out the loading of the belt, the valve 98IV is open to the device and the reservoir 22 is filled. The reservoir 24 is charged with the same roaniere. The pump 95 is then cleaned by forming a closed circuit by opening the valve 98III and the valve 98II to establish communication through the conduit 96A through the valve 98III. Toluene is then circulated by pump 95.

 To apply the hot paint, the temperature of this paint is maintained at 940C at the guns 58. To maintain the paint at this temperature, the temperature read at the thermometers 82 mounted on the exchangers 86 must be maintained at 122 C, which means that the oil located near the top of the coil 54 near the thermometer 82 is the hottest. The suitability of the paint heater depends on the volume sprayed by the guns. The higher the volume of paint to be applied, the higher the amount of heat required. It was therefore determined, in the design of the preferred embodiment, the optimum flow of paint flowing through the device.

When a paint truck travels approximately 12.87 km / h during paint application, it produces exhaust gas containing approximately 55,440 large calories (keal) of available heat per hour from a 7818 cc truck engine (although there is also approximately 27,720 kcal of heat per hour from the "Hercules" compressor).

The calculation of the dimensions of the reservoir 38, the tubes 42 and the exchangers 46, based on the above data, is carried out as follows. 22 UK gallons (100 dm3) of paint are required to paint a full solid line of 1609.34 m, while approximately 7 EU gallons (31.82 dm3) are required for marking a broken line of 1609.34 m. To determine the heat required to heat the paint to be used for any period of one hour, at 94 C, taking into account the ambient temperature (160C in summer, when most of the markings are made) during the application of this paint, it is assumed that 100 gallons -UK- (454.61 dm3) having a weight of 756.818 kg are sprayed per hour, assuming a specific heat substantially identical to that of water. heat required to raise the paint temperature is:
# 58.791.6 kcal.

 Thus, 100 UK gallons (454.61 dm3) of paint passing through heat exchanger 46 per hour should receive 58,791.6 l; cal from the oil bath. While the volume of the oil in the exchanger 46 is not critical, the flow rate of the oil in the exchanger 46 must be adjusted to ensure that the temperature read by the thermometer is maintained at 121 C. the calculation, we suppose a drop in temperature of the oil, from the top to the bottom of the exchanger, of about 15 C, this drop in temperature corresponding to the heat used for heating the paint, and a heat exchanger efficiency of about 90%. Thus, the oil must also be able to exchange 10/9 x 58,791.6 # 65,524 kcal per hour, so that the paint can absorb the required heat.

For this purpose, 160 gallons -UK- (727.36 dm3) of oil are used in the tank 38 and the exchangers 46, the oil constantly circulating in the closed device. In turn, the heat available in the oil must be absorbed by the exhaust gases. In this respect, assuming an efficiency of 85%, the exhaust gases must provide 20/17 x 65.) 24 # 76.851 keal. It is understood that the initial heat for heating the oil before any heating of the paint is usually obtained when the truck travels to the storage yard at the work location.

Due to the fact that approximately o316 kcal per hour can be transferred through 0.2418 m2 of steel surface, and that approximately 76.851 kcal per hour is required to heat the oil, 2.41b m2 of heat exchange surface must be provided inside the tubes 42 to transmit the heat of the gases to the oil bath.

The above calculations, essentially theoretical, were used as a basis for the construction of the heat exchange device.

Thus, taking into account the variations in the heat transfer properties of the various components, it is possible to choose 56 tubes 42 with a diameter of 38.1 mm, arranged at the bottom of the tank 58.

 As is obvious, and as follows from the above, it is possible to bring, without departing from the scope of the invention, any variant to the embodiments which have just been described only by way of example and without any limiting character.

Claims (6)

Claims  1. Heating device intended for the heating of a .atériau via the exhaust gases coming from an internal combustion engine, characterized in that it comprises a conduit coming from the internal combustion engine and leading to a series of small conduits for the passage of the heat evacuated through these conduits, the latter being immersed in an oil bath and passing through it and then being evacuated to the atmosphere, the interior walls of these conduits having a sufficient heat exchange surface and the conduits being in sufficient number to transmit a sufficient quantity of heat coming from the exhaust gases, through the pa ro @ of these conauits, in an oil bath, in order to heat @@ @ain liqul @ e, said bath surrounding the material intended to be heated, a bypass control being provided to prevent the gas from chappoment heated to circulate through the small conduits.  2. Heating device according to claim 1, characterized in that the oil bath is a thermal oil bath.  3. Heating device according to claim 2, characterized in that the material to be heated is in a tube passing through the oil bath.  4. Device according to claim 1,2 or 3, characterized in that the small conduits pass through a lower part of the bath, so that the heated oil rises and is replaced by cooler descending oil, thus creating a current convection inside the bath.  @. The heating device intended to be mounted on a truck, in order to ensure the heating of a paint. in a strip marking device on hot pavement, mounted on this truck, said truck comprising at least one internal combustion engine, each engine having an exhaust for discharging the exhaust gases produced during operation. of said internal combustion engine, the device for marking banae on hot pavement comprising paint storage tanks, paint spray guns, and connection tubes for bringing paint from the storage tanks to spray guns, said heating device comprising con @@ i @@ exhaust gas collectors fixed to the exhaust of each engine @ in order to collect the exhaust gases produced by each engine and leading to a series of small ducts passing through a thermal oil bath, the interior walls of the small conduits having a sufficient heat exchange surface and said conduits being in sufficient number to transmit a sufficient quantity of heat, coming from the exhaust gases, through the walls of these conduits , this as the only heat source for heating the thermal oil, the exhaust gases being discharged to the atmosphere after passing through. the small conduits, the thermal oil surrounding the tubes conveying the paint, in order to ensure the heating of this paint which must be applied hot by the spray guns, the device further comprising a thermal bypass to deflect the gases d exhaust, and therefore the heat passing through the heater. 6. Dispositi-f according to claim), characterized in that the small conduits - pass through an inner part of the oil bath, so that the heated oil rises and is replaced by cooler oil, thus creating a convection current inside the oil bath, the heated oil being in turn in communication with the outer walls of the tubes carrying the paint, so as to heat the paint to the desired temperature, before this paint is brought spray guns. 7. Device according to claim 5, characterized in that @oins two internal combustion engines are mounted on the c @@ ion, one engine being used to propel the truck, and at least one of these engines being part of a compressor used for spraying paint by means of spray guns, and in this case the thermal oil bath is divided into two parts, a part through which are arranged the small conduits carrying the exhaust gases, and a part through which the tubes carrying the paint are placed to heat it.