JP5592867B2 - Asphalt paving method and asphalt finisher - Google Patents

Description

  The present invention relates to asphalt pavement technology.

  Generally, an asphalt mixture is manufactured at a compounding plant, conveyed by a dump truck, and charged into an asphalt mixture input portion of an asphalt finisher. The asphalt mixture charging unit has a hopper that loads and temporarily stores the charged asphalt mixture, and a bar feeder that conveys the loaded asphalt mixture to the screed side. The asphalt mixture conveyed to the screed side is spread and leveled to perform pavement construction.

  By the way, the asphalt mixture is required to be paved in a preset temperature range. For example, in cold districts, cold seasons, nighttime construction, etc., problems such as a rapid temperature drop of the asphalt mixture and difficulty in obtaining a predetermined degree of compaction are likely to occur. In addition, there is a possibility that problems such as dragging and dragging holes on the leveling surface and problems such as insufficient adhesion of the joint portion of the pavement may occur. For this reason, it is preferable to avoid asphalt pavement construction in an environment where the outside air temperature is 5 ° C. or lower. In particular, in drainage pavement that requires a gap between asphalt mixtures, strict temperature control is required because there is a risk of quality deterioration due to a temperature drop.

  However, there are cases where construction in an environment where the outside air temperature is 5 ° C. or lower is unavoidable from the viewpoint of ordering schedules and year-round construction, and some measures are necessary. For example, measures can be taken such as increasing the temperature of the asphalt mixture at the time of shipment from the composite material factory or placing a heat insulating sheet on the loading platform of the dump truck during transportation. On the other hand, the heat released between the asphalt finisher and the paving work after the asphalt mixture is charged cannot be ignored.

  Patent Document 1 proposes an asphalt finisher hopper having a heat retaining function. This heat retention function can prevent the heat of the asphalt mixture from being dissipated to the outside air through the outer plate, and can suppress the temperature drop of the asphalt mixture.

JP-A-11-209918

  However, the present inventor has considered that the temperature drop of the asphalt mixture is not sufficiently suppressed even in the prior art. In an environment where the outside air temperature is 5 ° C. or lower, the surface temperature of the hopper or bar feeder is also 5 ° C. or lower. When the asphalt mixture is charged in this state, the initially loaded asphalt mixture comes into contact with the surface of the hopper or bar feeder, and the temperature drops rapidly. Since the hopper of the prior art has a heat retaining function, the temperature drop of the asphalt mixture to be charged later is suppressed by the heat of the asphalt mixture itself. However, the temperature drop of the asphalt mixture initially charged is inevitable.

  In particular, with respect to the bar feeder, there is no proposal for a heat retaining function even in the prior art. If the bar feeder does not have a heat retaining function, the asphalt mixture in which the temperature drop is suppressed by the heat retaining function of the hopper also drops in temperature when it comes into contact with the bar feeder surface.

  This invention solves the said subject, and it aims at providing the asphalt pavement method and asphalt finisher which can further suppress the temperature fall of an asphalt mixture.

The present invention for solving the above-mentioned problems is an asphalt pavement method under an ambient temperature of 5 ° C. or less, which is preliminarily heated to a bar feeder that is provided in an asphalt mixture charging portion of an asphalt finisher and conveys the asphalt mixture to 20 ° C. or higher. A preheating application step, an asphalt mixture charging step for charging the asphalt mixture into the asphalt mixture charging unit after the preheating is applied, and a pavement construction step for transporting and leveling the asphalt mixture from the asphalt mixture charging unit.

In asphalt pavement under an ambient temperature of 5 ° C or less, it is necessary to take measures to suppress the temperature drop of the asphalt mixed material. The temperature drop of the asphalt mixture can be further suppressed by preheating the asphalt mixture charging part (particularly the bar feeder) of the asphalt finisher to 20 ° C. or higher.

The present invention that solves the above problems is an asphalt pavement method under an ambient temperature of 5 ° C. or less, a preheating application step that preheats the asphalt mixture charging part of the asphalt finisher to 20 ° C. or higher, and after preheating application, An asphalt mixture charging step for charging the asphalt mixture into the asphalt mixture charging unit, and a pavement construction step for conveying and leveling the asphalt mixture from the asphalt mixture charging unit. Heat is supplied by the exhaust gas, and the exhaust gas is guided to a circulation path provided in the asphalt mixture charging section, and heat is applied to oil in an oil holding section provided along the circulation path.

Reusing exhaust gas is advantageous in terms of energy efficiency and cost. Further, the exhaust circuit has a simple configuration, and there is little risk of failure, which is advantageous in terms of maintenance.

With the oil heat retaining function, the asphalt mixture charging part can be maintained at 20 ° C. or higher for a certain period after the engine is stopped.

The present invention that solves the above problems is an asphalt pavement method using an asphalt finisher, a preheating application step that preliminarily applies heat to a bar feeder that conveys the asphalt mixture provided in the asphalt mixture charging part of the asphalt finisher, and preheating After the application, the method includes an asphalt mixture charging step for charging the asphalt mixture into the asphalt mixture charging unit, and a pavement construction step for transporting and leveling the asphalt mixture from the asphalt mixture charging unit.

The present invention for solving the above problems is an asphalt pavement method using an asphalt finisher, a preheating application step for applying heat to an asphalt mixture input part of the asphalt finisher in advance, and an asphalt mixture input part to the asphalt mixture input part after preheating application An asphalt mixture charging step, and a pavement construction step of conveying and leveling the asphalt mixture from the asphalt mixture charging part, and in the preheating application step, heat is applied by exhaust from the engine of the asphalt finisher, The exhaust gas is guided to a circulation path provided in the asphalt mixture charging section, and heat is applied to the oil in the oil holding section provided along the circulation path.

The present invention that solves the above-described problem is an asphalt finisher, and includes a preheating applying device that is provided in an asphalt mixture charging unit and that preheats a bar feeder that transports the asphalt mixture before the asphalt mixture is charged.

The present invention that solves the above-mentioned problems is an asphalt finisher, comprising a preheat application device that preheats the asphalt mixture input unit before charging the asphalt mixture, and the preheat application device is an exhaust from the engine of the asphalt finisher. Means for supplying heat, means for guiding the exhaust to a circulation path provided in the asphalt mixture charging section, and means for supplying heat to oil in an oil holding section provided along the circulation path.

  According to the present invention, the temperature drop of the asphalt mixture can be further suppressed as compared with the prior art.

It is a schematic block diagram of an asphalt finisher. It is the schematic (perspective view) explaining the preheating provision function of a hopper. It is the schematic (sectional drawing) explaining the preheating provision function of a hopper. It is the schematic (perspective view) explaining the preheating provision function of a bar feeder. It is the schematic (sectional drawing) explaining the preheating provision function of a bar feeder.

~Constitution~
The structure of the asphalt finisher according to this embodiment will be described. FIG. 1 is a schematic configuration diagram of an asphalt finisher. The asphalt finisher includes a crawler 1 for traveling, a driver's seat 2 for an operator to perform driving work, an asphalt mixture input unit 3 provided in front of the driver's seat 2 and into which the asphalt mixture is input from a dump truck, Various members such as a screw spreader 4 provided behind the driver's seat 2 for uniformly spreading the asphalt mixture to the paving width, and a screed 5 with a tamper provided behind the screw spreader 4 for compacting the asphalt mixture. It consists of devices.

  The asphalt mixture charging unit 3 includes a hopper 6 and a bar feeder 7. The hopper 6 is formed by opposingly arranging a pair of outer plates that are substantially L-shaped on the left and right with the bar feeder 7 in between. The outer plate of the hopper 6 has a posture in which the bottom plate surface is substantially parallel to the bar feeder 7 by the expansion and contraction operation of the cylinder (usually, in this posture, the asphalt mixture is introduced and temporarily stored) and the left and right outer sides are The posture can be changed to lift and slide the asphalt mixture to the bar feeder 7 side. The bar feeder 7 conveys the charged asphalt mixture backward.

  As a feature of this embodiment, the hopper 6 and the bar feeder 7 have a preheating function.

  2 and 3 are schematic diagrams for explaining the preheat application function of the hopper 6. The outer plate of the hopper 6 has a double plate structure composed of two steel plates 61 and 62, and a space extending along the steel plate surface is formed between the steel plates 61 and 62. A plurality of prisms 63 are arranged in a staggered manner in the space, and an exhaust circulation path 64 is formed by the arrangement of the prisms 63. Oil 65 is filled in the prism 63. An exhaust inlet 66 and an exhaust outlet 67 are formed on the outer plate of the hopper 6 formed in a double plate structure, and serve as an inlet and an outlet of the exhaust circulation path 64.

  Exhaust gas from an asphalt finisher engine (not shown) is guided to the hopper 6 through a muffler pipe 81. That is, the outlet end portion of the muffler pipe 81 and the exhaust inflow port 66 are continuous. The muffler pipe 81 is provided with a shutoff valve 82. If preheating is not required, the shut-off valve 82 is opened and the exhaust gas is released from the shut-off valve 82. However, when pre-heating is applied, the shut-off valve 82 is closed and the exhaust gas is guided to the exhaust circulation path 64 (details will be described later).

  The exhaust circulation path 64 once guides the exhaust flowing in from the exhaust inlet 66 to the lowermost part of the hopper 6, guides it to the exhaust outlet 67 while meandering upward from the lowermost part, and discharges it from the exhaust outlet 67. Thereby, the exhaust gas stays in the hopper 6 for a long time, and can apply heat uniformly.

  4 and 5 are schematic diagrams for explaining the preheat application function of the bar feeder 7. The bar feeder 7 includes a bottom plate 71 and a rotating portion 72 that is rotatably arranged around the bottom plate 71. A cavity is formed inside the bottom plate 71, and a plurality of prisms 73 are arranged in a staggered manner in the cavity, and an exhaust circulation path 74 is formed by the arrangement of the prisms 73. The prism 75 is filled with oil 75. An exhaust inlet 76 and an exhaust outlet 77 are formed on the side wall of the bottom plate 71, and serve as an inlet and an outlet of the exhaust circulation path 74.

  A part of the exhaust gas guided to the exhaust circulation path 64 in the hopper 6 is guided into the bottom plate 71 from the branch port 68 provided in the middle of the exhaust circulation path 64 through the branch pipe 83. That is, the end of the branch pipe 83 and the exhaust inlet 76 are continuous. The exhaust circulation path 74 guides the exhaust gas flowing in from the exhaust gas inlet 76 to the exhaust gas outlet 77 while meandering left and right, and discharges it from the exhaust gas outlet 77. Thereby, the exhaust stays in the bar feeder 7 for a long time, and can apply heat uniformly.

  In the present embodiment, each member including the rectangular column 63, the exhaust circulation path 64, the oil 65, the rectangular column 73, the exhaust circulation path 74, and the oil 75 constitutes a preheating application device.

~ Construction ~
An asphalt pavement method using the asphalt finisher of the present embodiment will be described.

  In general, the asphalt mixture is manufactured at a mixture factory and transported to a construction site by a dump truck. The asphalt finisher waits until the dump truck arrives at the construction site.

  During the standby, the asphalt finisher operator determines whether or not temperature drop suppression measures are necessary. In general, countermeasures are required for construction in an environment where the outside air temperature is 5 ° C. or lower. Although it is convenient and preferable to measure the outside air temperature, the surface temperature of the hopper 6 or the bar feeder 7 may be directly measured. When the outside air temperature or the surface temperature of the hopper 6 or the bar feeder 7 is 5 ° C. or less, the asphalt finisher is warmed up, the shut-off valve 82 is closed, and the exhaust from the engine is guided to the exhaust circulation paths 64 and 74.

  When the inventor of the present application conducted a confirmation test, the surface temperature of the hopper 6 near the exhaust inlet 66 becomes 60 ° C. due to the warming-up operation of the asphalt finisher in the environment of the outside air temperature of 5 ° C., and the hopper 6 near the exhaust outlet 67 The surface temperature and the surface temperature of the bar feeder 7 near the exhaust outlet 77 became 20 ° C. or higher.

  In addition, this inventor has confirmed that if the hopper 6 surface temperature and the bar feeder 7 surface temperature are 20 ° C. or higher, the influence of the temperature drop can be suppressed to an acceptable level.

  As described above, the asphalt mixture is put into the hopper 6 from the dump truck in a state where the hopper 6 and the bar feeder 7 are preheated. The temperature of the asphalt mixture charged from the dump truck is usually about 150 to 200 ° C. When the asphalt mixture at about 150 to 200 ° C. comes into contact with the surface of the hopper 6 and the bar feeder 7 that has been preheated to 20 to 60 ° C., the hopper 6 surface temperature and the bar feeder 7 surface temperature become 100 ° C. or higher. It was. It is presumed that the temperature of the asphalt mixture that is initially charged and contacts the surfaces of the hopper 6 and the bar feeder 7 is also 100 ° C. or higher.

  The asphalt mixture temporarily stored in the hopper 6 is conveyed by the bar feeder 7, spread by the screw spreader 4, and spread by the screed 5. After the asphalt mixture is introduced and during paving, exhaust from the engine is continuously guided to the exhaust circulation paths 64 and 74. The preheat application function of the hopper 6 and the bar feeder 7 operates as a heat retaining function.

  By the way, when waiting time becomes long, you may interrupt a warming-up operation temporarily from a viewpoint of fuel reduction (idling stop). When the exhaust gas circulates in the exhaust circulation paths 64 and 74, the oils 65 and 75 are heated. Due to the heat retaining effect of the oil, the surface temperature of the hopper 6 and the surface temperature of the bar feeder 7 can be maintained at 20 ° C. or higher for a while. The surface temperature of the hopper 6 and the surface temperature of the bar feeder 7 are measured, and when it becomes less than 20 ° C. over time, the warm-up operation is performed again.

~effect~
According to this embodiment, preheating is applied to the hopper 6 and the bar feeder 7 before the asphalt mixture is charged, so that the asphalt mixture initially charged in an environment where the outside air temperature is 5 ° C. or less is the hopper Even if it contacts the surface of 6 or the bar feeder 7, the temperature fall of an asphalt mixture can be suppressed.

  In addition, after the asphalt mixture is charged and during paving, the asphalt mixture can be kept warm as in the prior art, and the temperature drop of the asphalt mixture can be suppressed. That is, the temperature drop of the asphalt mixture can be further suppressed as much as the effect of applying preheating as compared with the prior art.

  The preheating is to reuse exhaust gas generated during the warm-up operation of the engine, which is excellent in terms of energy efficiency, does not require a special heat source, and is excellent in terms of cost.

  The exhaust circulation paths 64 and 74 have a simple configuration, are less likely to break down, and are excellent in terms of maintenance.

~ Modification ~
(1) In this embodiment, preheating is applied to the hopper 6 and the bar feeder 7, but preheating may be applied to either the hopper 6 or the bar feeder 7. Although not as effective as the present embodiment, the temperature drop of the asphalt mixture can be suppressed as compared with the prior art.

  (2) In this embodiment, the exhaust circulation path 74 in the bar feeder 7 is provided by branching from the exhaust circulation path 64 in the hopper 6, but the exhaust inlet 76 is directly continuous with the muffler pipe 81. Also good.

  (3) In the present embodiment, preheating is applied by exhaust from the engine, but a heating wire may be wired inside the hopper 6 and the bar feeder 7 and preheating may be applied by electric power from the battery of the asphalt finisher. However, the effect regarding the energy efficiency and cost of this embodiment is not acquired. Further, when the rotating portion 72 rotates around the bottom plate 71, vibration due to the rotation propagates to the bottom plate 71, which may cause a failure of the electric system, and the effect of the maintenance of the present embodiment is also possible. I can't get it.

  (4) In this embodiment, the prisms 63 and 73 are filled with the oils 65 and 75, but may be filled with water or air as a heat insulating material.

DESCRIPTION OF SYMBOLS 1 Crawler 2 Driver's seat 3 Asphalt mixture insertion part 4 Screw spreader 5 Screed 6 Hopper 7 Bar feeder 61, 62 Steel plate 63 Square pillar 64 Exhaust circulation path 65 Oil 66 Exhaust inlet 67 Exhaust outlet 68 Branch outlet 71 Bottom plate 72 Rotating part 73 Square column 74 Exhaust circuit 75 Oil 76 Exhaust inlet 77 Exhaust outlet 81 Muffler pipe 82 Shut-off valve 83 Branch pipe

Claims (9)

An asphalt pavement method under an ambient temperature of 5 ° C or less,
A preheating application step in which the bar feeder that is provided in the asphalt mixture charging unit of the asphalt finisher and that transports the asphalt mixture is preheated to 20 ° C. or higher;
An asphalt mixture charging step of charging the asphalt mixture into the asphalt mixture charging part after preheating,
A pavement construction step for conveying and leveling the asphalt mixture from the asphalt mixture charging section,
In the bar feeder, the rotating part is arranged to be rotatable around the bottom plate,
In the preheating application step,
Heat is provided by the exhaust from the asphalt finisher engine,
An asphalt pavement method , wherein the exhaust gas is guided to a circulation path provided in a bottom plate of the bar feeder . 2. The asphalt pavement method according to claim 1, wherein, in the preheating application step, heat is applied in advance to a hopper that is provided in the asphalt mixture charging unit and temporarily stores the asphalt mixture. An asphalt pavement method under an ambient temperature of 5 ° C or less,
A preheating step for preheating the asphalt mixture charging portion of the asphalt finisher to 20 ° C. or higher;
An asphalt mixture charging step of charging the asphalt mixture into the asphalt mixture charging part after preheating,
A pavement construction step for conveying and leveling the asphalt mixture from the asphalt mixture charging section,
In the preheating application step,
Heat is provided by the exhaust from the asphalt finisher engine,
The exhaust is led to a circulation path provided in the asphalt mixture charging part,
An asphalt pavement method characterized in that heat is applied to oil in an oil holding portion provided along the circulation path. The asphalt pavement method according to claim 3, wherein, in the preheating application step, heat is applied in advance to a bar feeder that is provided in the asphalt mixture charging section and conveys the asphalt mixture. The asphalt pavement method according to claim 3, wherein, in the preheating application step, heat is applied in advance to a hopper that is provided in the asphalt mixture charging section and temporarily stores the asphalt mixture. Asphalt paving method using asphalt finisher,
A preheating application step for preheating heat to a bar feeder that is provided in an asphalt mixture charging section of the asphalt finisher and that transports the asphalt mixture;
An asphalt mixture charging step of charging the asphalt mixture into the asphalt mixture charging part after preheating,
A pavement construction step of conveying and leveling the asphalt mixture from the asphalt mixture charging part;
With
In the bar feeder, the rotating part is arranged to be rotatable around the bottom plate,
In the preheating application step,
Heat is provided by the exhaust from the asphalt finisher engine,
An asphalt pavement method , wherein the exhaust gas is guided to a circulation path provided in a bottom plate of the bar feeder . Asphalt paving method using asphalt finisher,
A preheating step for preheating the asphalt mixture input portion of the asphalt finisher;
An asphalt mixture charging step of charging the asphalt mixture into the asphalt mixture charging part after preheating,
A pavement construction step for conveying and leveling the asphalt mixture from the asphalt mixture charging section,
In the preheating application step,
Heat is provided by the exhaust from the asphalt finisher engine,
The exhaust is led to a circulation path provided in the asphalt mixture charging part,
An asphalt pavement method characterized in that heat is applied to oil in an oil holding portion provided along the circulation path. An asphalt finisher used in the asphalt pavement method according to claim 1 or 6 ,
An asphalt finisher comprising: a preheating applying device that preliminarily heats a bar feeder that conveys the asphalt mixture, which is provided in the asphalt mixture introduction unit, before the asphalt mixture is charged. An asphalt finisher used in the asphalt pavement method according to claim 3 or claim 7 ,
A preheating application device for preheating the asphalt mixture charging unit before charging the asphalt mixture;
The preheating device is:
Means for applying heat by exhaust from the engine of the asphalt finisher;
Means for directing the exhaust to a circulation path provided in the asphalt mixture charging part;
An asphalt finisher comprising: means for applying heat to oil in an oil holding portion provided along the circulation path.

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