JP4117213B2 - Asphalt injection pipe for asphalt plant - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an asphalt injection pipe of an asphalt plant for producing an asphalt mixture which is a road pavement material.
[0002]
[Prior art]
In recent years, the demand for special asphalt mixtures having different properties from ordinary asphalt mixtures, such as drainage asphalt mixtures, has been increasing rapidly, and the opportunity to use special asphalts with high viscosity has been increasing accordingly.
[0003]
FIG. 3 shows an asphalt supply apparatus equipped with an asphalt injection pipe mounted on the plant body of a conventional asphalt plant. The asphalt metering tank 103 is provided in the vicinity of the mixing tank 102 of the mixer 101, and the upper part of the mixing tank 102 is shown in FIG. An asphalt injection pipe 105 having a plurality of injection nozzles 104 is disposed, and asphalt measured in the asphalt measurement tank 103 is sent to the asphalt injection pipe 105 by the supply pump 106 and mixed from the injection nozzle 104 to the mixing tank 102. Asphalt is sprayed inward.
[0004]
A heating and heat retaining heater 107 is attached to the pipe surface of the asphalt injection pipe 105. The asphalt injection pipe 105 itself is heated and maintained at the same temperature as that of the asphalt to heat and maintain the asphalt that is fed, thereby improving the flowability of the asphalt. It is maintained and smoothly ejected from the ejection nozzle 104.
[0005]
[Problems to be solved by the invention]
However, if high-viscosity asphalt is frequently used, asphalt adheres and grows within the asphalt injection pipe in a short period of time, and the injection nozzle is blocked, increasing the number of times the asphalt injection pipe is replaced and cleaned, making maintenance difficult. The problem that it is.
[0006]
This invention makes it a subject to provide the asphalt injection pipe of the asphalt plant which can prevent that the injection nozzle of an asphalt injection pipe obstruct | occludes as much as possible in view of said point.
[0007]
[Means for Solving the Problems]
As a result of pursuing the cause of blocking the injection nozzle, the present 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 temperature higher than the pipe surface set temperature. Therefore, the pipe of the heater mounting part is heated more than necessary, and asphalt remaining on the inner wall of the pipe is carbonized and solidified, or the residue is gradually clogged by clogging the injection nozzle part. Especially in high-viscosity asphalt, there is a large amount remaining on the inner wall of the pipe, and the carbonization of the asphalt is further promoted by increasing the heating set temperature in order to maintain fluidity, and the injection nozzle is blocked in a short time. Injecting nozzles that the asphalt injection pipe itself is heated to a high temperature by a heater Came to the conclusion that if not the major cause of infarction.
[0008]
Therefore, in order to solve the above problems, in the asphalt injection pipe of the asphalt plant of the present invention, a rod-shaped heater protection tube is inserted into the inside from the free end portion side of the asphalt injection pipe, and the heater protection tube A positioning rib is fixed to the peripheral surface of the tip of the asphalt injection pipe so that the tip is located at the center of the asphalt injection pipe, and a heater for heating and keeping the asphalt inside the heater protection tube is provided. It is said.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
According to the asphalt injection pipe of the asphalt plant according to the present invention, an asphalt heating and insulation heater is inserted into the asphalt injection pipe, and the asphalt is directly heated by this heater. As a result, the asphalt adhered to the inner wall of the asphalt injection pipe is not heated and carbonized more than necessary, and the injection nozzle can be prevented from being blocked as much as possible.
[0010]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0011]
FIG. 1 shows an asphalt supply device equipped with an asphalt injection pipe mounted on the main body of an asphalt plant. The asphalt metering tank 3 is provided in the vicinity of the mixing tank 2 of the mixer 1, and the upper part of the mixing tank 2 is shown above. An asphalt injection pipe 4 which is a tubular body is disposed horizontally. 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]
Further, 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 middle of the supply pipe 6. Also. On the pipe surface of the asphalt injection pipe 4, a heater 8 for heating and keeping asphalt is attached. Reference numeral 9 denotes an extraction pipe for extracting asphalt remaining in the asphalt injection pipe 4.
[0013]
A heater 10 for heating and keeping the asphalt from the inside of the pipe is attached to the inside of the asphalt injection pipe 4 as shown in FIG. The heater 10 is housed in a rod-shaped heater protective tube 11 inserted into the pipe from the free end side of the asphalt injection pipe 4 so as not to come into direct contact with the asphalt. Further, a positioning rib 12 is fixed to the peripheral surface of the tip of the heater protection tube 11 so that the tip of the heater protection tube 11 is located at the center of the asphalt injection pipe 4 when the heater protection tube 11 is inserted. Reference numeral 13 denotes a temperature sensor that measures the ambient temperature or the like in the heater protection tube 11, and controls the heating of the heater 10 based on the temperature sensor 13.
[0014]
The inventor conducted an asphalt adhesion test using the asphalt injection pipe 4. The heater 10 in the asphalt injection pipe 4 is heated and controlled so that the ambient temperature in the protective tube 11 is approximately equal to the asphalt temperature, and the external heater 8 attached to the asphalt injection pipe 4 removes the asphalt adhering to the inner wall of the pipe. When the test was conducted to keep the temperature without raising the temperature so as not to cause carbonization, the blockage period of the injection nozzle 5 could be extended more than three times despite the frequent use of high viscosity asphalt. As a result, if the heater 10 is inserted into the asphalt injection pipe 4 and the asphalt is directly heated, the injection nozzle 5 can be prevented from being blocked as much as possible, and the frequency of replacement and cleaning of the asphalt injection pipe 4 can be reduced and maintenance can be facilitated. There was found.
[0015]
In the above embodiment, the external heater 8 for heating the asphalt injection pipe 4 and the internal heater 10 are both attached. However, the external heater 8 is omitted and only the internal heater 10 is used. 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, the rod-shaped heater protection tube is inserted into the inside from the free end portion side of the asphalt injection pipe, and the peripheral surface of the tip portion of the heater protection tube is inserted. Has a rib for positioning so that its tip is positioned at the center of the asphalt injection pipe, and a heater for heating and keeping the asphalt inside the heater protection pipe, so that the asphalt attached to the inner wall of the asphalt injection pipe Is not heated and carbonized more than necessary, the injection nozzle is prevented from being blocked as much as possible, the frequency of replacement and cleaning of the asphalt injection pipe is reduced, and maintenance can be facilitated.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an embodiment of an asphalt injection pipe according to the present invention.
FIG. 2 is an enlarged view of a main part in which a part of FIG. 1 is omitted.
FIG. 3 is a view 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 the peripheral surface, a rod-shaped heater protection tube is inserted into the inside from the free end side of the asphalt injection pipe, and on the peripheral surface of the tip portion of the heater protection tube An asphalt injection pipe for an asphalt plant , wherein a positioning rib is fixed so that a tip portion of the asphalt injection pipe is positioned at the center of the asphalt injection pipe, and a heater for heating and maintaining the asphalt is provided in the heater protection pipe. .

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