JP2004332378A - Asphalt ejection pipe for asphalt plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an asphalt ejection pipe for an asphalt plant, which prevents clogging of an ejection nozzle thereof to the utmost. <P>SOLUTION: According to the structure of the asphalt ejection pipe, a rod-shaped heater protective pipe 11 is inserted into the asphalt ejection pipe 4, and an asphalt heating and heat insulating heater is installed in the heater protective pipe 11, to thereby directly heat asphalt by the heater. Thus problems of excessive heating of the asphalt adhering to an inner wall of the asphalt ejection pipe 4 and carbonization of the asphalt are eliminated, and therefore clogging of the ejection nozzle is prevented to the utmost. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an asphalt injection pipe of an asphalt plant for producing an asphalt mixture as a road pavement material.
[0002]
[Prior art]
In recent years, the demand for special asphalt mixtures having different properties from ordinary asphalt mixtures, for example, drainage asphalt mixtures, has been rapidly increasing, and accordingly, opportunities to use high-viscosity special asphalts have also increased.
[0003]
FIG. 3 shows an asphalt supply device provided with an asphalt injection pipe mounted on a plant body of a conventional asphalt plant, which is provided with an asphalt measuring tank 103 near a mixing tank 102 of a mixer 101, An asphalt injection pipe 105 having a plurality of injection nozzles 104 is provided, and asphalt measured in an asphalt measurement tank 103 is fed into the asphalt injection pipe 105 by a supply pump 106, and the mixing tank 102 is discharged from the injection nozzle 104. Injecting asphalt inward.
[0004]
A heater 107 is attached to the surface of the asphalt injection pipe 105 to heat and maintain the asphalt to be fed by heating and maintaining the asphalt injection pipe 105 itself at the same temperature as the asphalt, thereby improving the fluidity of the asphalt. The nozzle is maintained so as to smoothly eject from the ejection nozzle 104.
[0005]
[Problems to be solved by the invention]
However, if high-viscosity asphalt is used frequently, asphalt adheres and grows in the asphalt injection pipe in a short period of time, closing the injection nozzle, increasing the number of replacements and cleaning of the asphalt injection pipe, and maintenance is difficult. Is a problem.
[0006]
In view of the above, an object of the present invention is to provide an asphalt injection pipe for an asphalt plant that can prevent the injection nozzle of the asphalt injection pipe from being blocked as much as possible.
[0007]
[Means for Solving the Problems]
As a result of pursuing the cause of closing the injection nozzle, the inventor controls the heating of the heater attached to the asphalt injection pipe based on the pipe surface temperature, but the heater itself has a high temperature equal to or higher than the pipe surface set temperature. For this reason, the pipe at the heater attachment part is heated more than necessary, and the asphalt remaining on the pipe inner wall is carbonized and solidified, and this scum is clogged in the injection nozzle part and the injection nozzle is gradually closed. In particular, asphalt with high viscosity has a large amount of adhering and remaining on the inner wall of the pipe, and carbonization of the asphalt is further promoted by increasing the heating set temperature to maintain fluidity, and the injection nozzle is blocked in a short time. It is guessed that it is caused by the injection nozzle, it is heating the asphalt injection pipe itself to a high temperature by the heater Came to the conclusion that if not the major cause of infarction.
[0008]
Therefore, in order to solve the above-mentioned problem, in the asphalt injection pipe of the asphalt plant of the present invention, a rod-shaped heater protection pipe is inserted inside the asphalt injection pipe, and the inside of the heater protection pipe is used for asphalt heating and heat retention. It features a heater inside.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the asphalt injection pipe of the asphalt plant according to the present invention, the asphalt heating / heating heater is inserted inside the asphalt injection pipe, and the asphalt is directly heated by the heater. This prevents the asphalt adhering to the inner wall of the asphalt injection pipe from being heated more than necessary and carbonized, thereby preventing the injection nozzle from being blocked as much as possible.
[0010]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0011]
FIG. 1 shows an asphalt supply device provided with an asphalt injection pipe mounted on a plant body of an asphalt plant. The asphalt measuring tank 3 is provided near a mixing tank 2 of a mixer 1. An asphalt injection pipe 4 as a pipe is horizontally disposed. Around the asphalt injection pipe 4, a plurality of injection nozzles 5 for injecting asphalt into the mixing tank 2 are provided at predetermined intervals.
[0012]
The asphalt measuring tank 3 and the asphalt injection pipe 4 are connected by a supply pipe 6, and a supply pump 7 for asphalt pressure feeding is interposed in the supply pipe 6. Also. A heater 8 for heating and keeping asphalt is attached to the surface of the asphalt injection pipe 4. Reference numeral 9 denotes a withdrawal pipe for removing asphalt remaining in the asphalt injection pipe 4.
[0013]
As shown in FIG. 2, a heater 10 for heating and heating the asphalt from the inside of the pipe is attached inside the asphalt injection pipe 4. The heater 10 is housed in a rod-shaped heater protection tube 11 inserted into the asphalt injection pipe 4 from the free end side thereof so as not to come into direct contact with the asphalt. A positioning rib 12 is fixed to the peripheral surface of the distal end of the heater protection tube 11 so that the distal end is positioned at the center of the asphalt injection pipe 4 when the heater protection tube 11 is inserted. Reference numeral 13 denotes a temperature sensor for measuring an ambient temperature or the like in the heater protection tube 11, and controls heating of the heater 10 based on the temperature sensor 13.
[0014]
The inventor performed an asphalt adhesion test using the asphalt injection pipe 4. The heater 10 in the asphalt injection pipe 4 controls heating so that the ambient temperature in the protective tube 11 becomes approximately equal to the asphalt temperature, and the external heater 8 attached to the asphalt injection pipe 4 removes asphalt adhering to the pipe inner wall. A test was conducted with the temperature kept high without raising the temperature to prevent carbonization. As a result, the closing period of the injection nozzle 5 could be extended by three times or more despite the frequent use of high-viscosity asphalt. Accordingly, if the heater 10 is inserted into the asphalt injection pipe 4 to directly heat the asphalt, the injection nozzle 5 can be prevented from being clogged as much as possible, and the frequency of replacement and cleaning of the asphalt injection pipe 4 is reduced, so that maintenance becomes easier. There was found.
[0015]
In the above embodiment, both the external heater 8 for heating the asphalt injection pipe 4 and the internal heater 10 are shown, but the external heater 8 is omitted and only the internal heater 10 is used. The asphalt may be heated and kept warm.
[0016]
【The invention's effect】
As described above, according to the asphalt injection pipe of the asphalt plant according to the present invention, a rod-shaped heater protection pipe is inserted inside the asphalt injection pipe, and a heater for heating and maintaining asphalt is provided inside the heater protection pipe. The asphalt adhering to the inner wall of the injection pipe is not excessively heated and carbonized, the clogging of the injection nozzle is prevented as much as possible, and the frequency of replacement and cleaning of the asphalt injection pipe is reduced, so that maintenance can be facilitated.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing one embodiment of an asphalt injection pipe according to the present invention.
FIG. 2 is an enlarged view of a main part with a part of FIG. 1 omitted.
FIG. 3 is a diagram illustrating a conventional asphalt injection pipe.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Mixer 2 ... Mixing tank 4 ... Asphalt injection pipe 5 ... Injection nozzle 10 ... Heater 11 ... Heater protection pipe

Claims (1)

In an asphalt injection pipe of an asphalt plant in which an injection nozzle is arranged on a peripheral surface, a rod-shaped heater protection pipe is inserted inside the asphalt injection pipe, and a heater for asphalt heating and keeping heat is provided inside the heater protection pipe. Asphalt injection pipe of asphalt plant.

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