JPH08258153A - Pipe identification method and device, plastic pipe used in the method and device, and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Objective] A heating wire is embedded in the contact surface with the plastic tube, and fusion with the tube is performed by applying a predetermined amount of power to the heating wire and heating and melting the contact surface. When performing fusion bonding between an electrofusion joint and a plastic pipe, the pipe is not suitable for fusion by mistake and the fusion becomes unstable and the prescribed fusion strength cannot be obtained. Make sure that there is no risk of problems such as disconnection of the pipe. [Structure] The optical sensor 12 detects the color of the pipe surface, which is defined by JIS, for each type of pipe, and the CPU 2 identifies the type of pipe from the detected color, and a plastic pipe suitable for fusion bonding. Is determined. When it is determined that it is not suitable, the start switch 5 is turned on.
Even if operated, the control signal for turning on the switch 6 is not output, and the fusion current is not supplied to the electrofusion joint 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for identifying the suitability of a pipe to be fused with an electrofusion joint in which a heating wire is embedded in a contact surface with the pipe, which is used for connecting plastic pipes. The present invention relates to an apparatus, a method and a plastic pipe used in the apparatus, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Electrofusion as disclosed in Japanese Patent Application Laid-Open No. 61-130695, Japanese Patent Publication No. 63-40993, etc. has recently been developed as a pipe joint for plastic pipes used for gas pipes and water and sewer pipes. There is a joint.
Such an electrofusion joint is disclosed in Japanese Patent Laid-Open No. 3-4.
Using a fusing device such as that shown in No. 7737, the type of joint to the heating wire embedded in the contact surface with the plastic pipe,
The fusion with the plastic pipe is performed by supplying an appropriate amount of electric power according to the diameter and the like.

[0003]

Although some of the above-mentioned conventional fusing devices have the function of identifying the type of joint, those having the function of identifying the type of pipe. There is no. There are various types of pipes used for gas pipes, water and sewer pipes, and some pipes are not suitable for fusion with an electrofusion joint. For example, metal pipes, plastic pipes, vinyl chloride pipes, cross-linked polyethylene pipes, etc. are the same, and if these pipes are mistakenly used for the fusion work with the electrofusion joint, the fusion will be incomplete and the prescribed fusion will occur. The strength may not be obtained, and troubles such as gas leakage, water leakage, and separation of the pipe from the joint may occur.

The present invention has been made to solve the above problems, and is used in a method and apparatus for identifying the suitability of a tube used for fusion bonding with an electrofusion joint, and the method and apparatus. It seeks to provide a plastic tube and its manufacturing method.

[0005]

SUMMARY OF THE INVENTION Therefore, in order to determine the suitability of fusion of an electrofusion joint and a plastic pipe before the fusion of the electrofusion joint and a plastic pipe, a sensor is used to identify the type of pipe. . Another invention has a switch means for starting the supply of electric power to an electrofusion joint in which a heating wire is embedded in the contact surface with a plastic tube, and an identification means for identifying the type of the joint, and the switch means is turned on. Then, an appropriate amount of electric power is supplied to the electrofusion joint according to the type of the joint identified by the identifying means, and a sensor for identifying the type of the pipe in the fusion device that fuses the electrofusion joint and the plastic pipe. And a determination means for determining whether or not the fusion with the electrofusion joint is appropriate based on the type of the tube identified by the sensor, and preferably the switch means is turned off by the determination of the determination means. The second switch means, which is turned off according to the determination result of the determination means, is in series with the first switch means. Provided, the supply of power to the joint is so not performed.

The device is also preferably provided with display means for displaying the results determined by the determination means. The sensor used in each of the above inventions includes, for example, a light emitting unit and a light receiving unit, light from the light emitting unit is applied to the tube surface, the reflected light received by the light receiving unit is passed through a filter of a specified color, and the light passing through the filter is An optical sensor that identifies the color of the tube surface by converting the current, an optical sensor that identifies the color of the tube surface by reading the wavelength of the reflected light that is applied to the tube surface, and ultrasonic waves from the outside of the tube in the diameter direction. Sensor to measure the thickness of the pipe by reading the time until it bounces from the inner peripheral surface of the pipe, a magnetic sensor for identifying the powder on the surface of the pipe or for detecting metal powder such as magnetic powder or iron powder embedded in the pipe. Examples include a bar code displayed on the tube surface, a sensor for reading characters or symbols, and the like.

In another invention in which the sensor is a magnetic sensor, the plastic pipe used in each of the above inventions includes:
Magnetic powder or metal powder such as iron powder is added to the surface layer or the surface or embedded in the pipe, and the magnetic powder or metal powder is applied or embedded at the time of forming the pipe.

[0008]

As described above, there are various types of pipes used for gas pipes and sewer pipes. In JIS, in order to identify such pipes, for example, white is used for cross-linked polyethylene pipes, green is used for non-cross-linked polyethylene pipes and double-layered polyethylene pipes whose surface layer is non-cross-linked polyethylene pipe, beige for polybutene pipes, and vinyl chloride pipes. It is stipulated that gray and different colors should be applied to the surface. In addition, the above-mentioned pipes generally have the same outer diameter,
The wall thickness varies depending on the type of pipe. Therefore, for example, by detecting the color colored on the tube surface with an optical sensor, it is possible to judge from the detected color whether or not the judging means is a plastic tube suitable for fusion bonding with the electrofusion joint. In the preferred apparatus, when it is determined that the pipe is not suitable, even if the switch means is turned on to start the fusion, the joint is not supplied with electric power.

In another preferred apparatus, the judgment result of the judgment means is displayed as a warning sound such as a buzzer and / or an LED display or character information on a CRT or a liquid crystal screen by the display means. Even in the case of a sensor that detects the wall thickness of a pipe by ultrasonic waves, it is judged from the wall thickness of the pipe detected by the sensor whether the determination means is a plastic pipe suitable for fusion bonding with the electrofusion joint.

Also in the case of a magnetic sensor, when the magnetic sensor detects magnetic powder or iron powder embedded in the tube surface or in the tube, the determination means determines whether or not it is a plastic tube suitable for fusion bonding. When reading a bar code, a character or a symbol on the tube surface with a sensor, it is similarly determined whether or not the plastic tube is suitable for fusion bonding.

[0011]

[Embodiment] The fusing apparatus 1 is a CPU 2 which also serves as a judging means.
And a liquid crystal display (hereinafter referred to as “LC
3), the power switch 4 and the start switch 5 that are turned on and off, and the start switch 5 are in series, and the start switch 5 is turned on.
Further, as will be described later, the plastic pipe inserted in the joint is a non-crosslinked polyethylene pipe, a two-layer polyethylene pipe having a non-crosslinked polyethylene surface layer, a polybutene pipe, or other suitable plastic pipe for fusion. Is determined by the control signal transmitted from the CPU 2,
The switch 6 that is operated N, the switch 7 that is parallel to the switch 6, the connector 11 that is inserted into the socket 9 of the electrofusion joint 8, and the optical sensor 12, and the optical sensor 12 further includes the electrofusion joint. Micro switch 1 that is pressed to turn on when it is applied to the plastic tube 13a or 13b inserted in
4 and, when the micro switch 14 is turned on, it emits light, or when the micro switch 14 is turned on,
The light emitting diode LED15 that emits light according to the control signal from the CPU2, the photodetector 16 that receives the light applied to the tube surface from the light emitting diode 15, and the light of the designated color among the light received by the photodetector 16 A filter 17 that passes the light, a converter 18 that converts the light that has passed through the filter 17 into a current, and a conversion current that is binarized
2 has a binarization circuit 19 which outputs 0 V or 5 V.

The present apparatus is constructed as described above, and the terminals 13 in the socket and the connector 1 (not shown) are inserted by inserting the plastics 13a and 13b into the electrofusion joint 8 from both sides and the connector 11 into the socket 9.
1 terminal. Then turn on the power switch 4,
The optical sensor 12 is first applied to one plastic tube 13a or 13b of the two plastic tubes 13a and 13b. The optical sensor 12 is attached to the plastic tube 13a or 13b.
When the micro switch 14 is turned on, the CPU
The light emitting diode 15 emits light in response to the control signal from 2. Then, the light is applied to the tube surface, the reflected light is passed through the filter 17, and then the photo detector 16
Is received by. The light of the designated color received by the photo detector 16 is sent to the converter 18. The amount of light is large when the surface of the tube is the designated color and is small when it is other than the designated color. Therefore, the electric current converted by the converter 18 is large when the tube surface has the designated color and is minute when the tube surface has a color other than the designated color.

The current converted by the converter 18 is binarized by the binarization circuit 19 according to its magnitude, and the binarized circuit 19 outputs 0 to the CPU 2.
V or 5V is output, and the CPU 2 determines whether the plastic tube 13a or 13b to be fused is suitable based on the output. That is, it is judged to be unsuitable when 0V and suitable when 5V. Then, the result is output to the LCD 3 and displayed.

When the suitability of one of the fused plastic tubes is determined as described above, the optical sensor 12 is applied to the other plastic tube, and the suitability of the tube is similarly determined. Next, start switch 5 is turned on to start fusion.
Manipulate. Then, the CPU 2 determines that both plastic tubes 13a
When it is determined that the pipes 13 and 13b are both suitable for fusion bonding, a control signal is output to the switch 6,
Turn on. When it is determined that either one of the plastic pipes or both of the plastic pipes is unsuitable, the control signal for turning on the switch 6 is not output even if the start switch 5 is turned on, and therefore the fusion is not started. . When the switch 6 is turned on, a weak inspection current is passed through the heating wire (not shown) of the electrofusion joint 8, and the CPU 2 reads the resistance value of the heating wire from the current passed through the heating wire and the joint 8 Determine the type.

The CPU 2 then outputs a control signal to the switches 6 and 7 to turn off the switch 6 and turn on the switch 7, and supply the joint 8 with the amount of electric power selected corresponding to the type of the joint 8. At this time, the supply of the amount of electric power is corrected by the CPU 2 according to the environmental temperature measured by the temperature sensor 20 so as to be small when the environmental temperature is high and large when the environmental temperature is low. When the predetermined amount of electric power is supplied as described above, the CPU 2 outputs a control signal for turning off the switch 7 and ends the fusion.

In another example, a magnetic sensor is used as a sensor, and the magnetic powder is applied or adhered to the surface of a plastic tube suitable for fusion bonding, or is mixed in a printing material for the tube during printing of the tube. Or embedded in the material by kneading into the material during molding. This magnetic powder is
Similarly, metal powder such as iron powder may be kneaded and embedded at the time of addition or molding, and then magnetized in a later step.

If the magnetic sensor itself generates a magnetic field, non-magnetized metal powder such as iron powder can be used as it is. That is, the same detection can be performed by the disturbance of the magnetic field. In yet another example, a pen-type bar code reader is used as the sensor, and the bar code is printed directly on the tube surface or printed on a sticker and attached. In this case, the barcode signal read by the barcode reader is converted into a digital value by the decoder circuit and input to the CPU. Then, the CPU determines the suitability of the pipe as in the above.

Since at least two types of information to be read from the bar code are appropriate and inadequate, it is possible to read the information other than the bar code, for example, characters or figures.

[0019]

According to the method and apparatus of the present invention, prior to fusing the electrofusion joint and the plastic tube, it is possible to judge whether the plastic tube is suitable for fusing or not. The pipes that are not suitable for fusing are not used by mistake, and the fusing is unstable and the desired fusing strength cannot be obtained. There is no risk of trouble such as leaving the car. In addition, it is possible to determine whether or not a pipe is suitable for fusion bonding, even for existing pipes, by detecting the colored color on the pipe surface and detecting the wall thickness. If metallic powder such as magnetic powder or iron powder is added to or embedded in, it is possible to determine suitability in the same manner using a magnetic sensor. The suitability can be similarly determined by displaying a bar code, a character, a graphic or the like on the surface of the tube.

Further, when the judging means judges that it is not suitable,
If power is not supplied even when the switch means is turned on, a tube that is not suitable for fusion will not be accidentally fused. Further, by making it possible to display the determination result of the determination means, it is possible to know the suitability of the fusion of the pipes.

Also, if magnetic powder or metal powder is added or embedded during the formation of the plastic pipe, the number of post-processing steps can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic view of a fusion bonding apparatus according to the present invention.

FIG. 2 is a diagram showing another example of a sensor.

[Explanation of symbols]

1 ・ ・ Fusing device 2 ・ ・ CPU 3 ・ ・ Liquid crystal display LCD 4 ・ ・ Power switch 5 ・ ・ Start switch 6、7 ・ ・ Switch 8 ・ ・ Electrofusion joint 9 ・ ・ Socket 11 ・ ・ Connector 12 ・ ・ Optical Sensor 13a, 13b ··· Plastic tube 14 · · Micro switch 15 · · Light emitting diode LED 16 · · Photodetector 17 · · Filter 18 · · Converter 19 · · Binarization circuit 20 · · Temperature sensor 21 · · Ultrasonic wave Sensor 22 Decoder circuit

Claims (12)

[Claims] 1. An electrofusion joint and a plastic in which a heating wire is embedded in a contact surface with a plastic tube, and fusion with the tube is performed by applying a predetermined amount of electric power to the heating wire to heat and melt the contact surface. A method for identifying a pipe, wherein a type of the pipe is identified by a sensor in order to determine whether or not the fusion with the joint is appropriate before the fusion with the pipe. 2. A switch means for starting the supply of electric power to an electrofusion joint in which a heating wire is embedded in a contact surface with a plastic pipe, and an identification means for identifying the type of the joint, and the switch means is turned on. Then, an appropriate amount of electric power is supplied to the electrofusion joint according to the type of the joint identified by the identifying means, and a sensor for identifying the type of the pipe in the fusion device that fuses the electrofusion joint and the plastic pipe. And a determining means for determining whether or not the fusion with the electrofusion joint is appropriate based on the type of the tube identified by the sensor. 3. The sensor used in the method according to claim 1 and the device according to claim 2, comprising a light emitting part and a light receiving part, wherein light is applied to the tube surface from the light emitting part and reflected light is applied to a filter of a designated color. After passing, it is an optical sensor that receives the light at the light receiving part and converts the current to identify the color of the tube surface. 4. The sensor used in the method according to claim 1 and the device according to claim 2, wherein the sensor for identifying the color of the tube surface by reading the wavelength of the reflected light of the light applied to the tube surface. Is. 5. The sensor used in the method according to claim 1 and the device according to claim 2, wherein ultrasonic waves are diametrically applied from the outside of the tube, and the time taken for the ultrasonic wave to bounce off from the inner peripheral surface of the tube is read. Is a sensor that measures the thickness of the. 6. The sensor used in the method according to claim 1 and the device according to claim 2, wherein the sensor is a magnetic sensor for detecting metal powder such as magnetic powder or iron powder added to or embedded in the tube surface for identification. Is. 7. The sensor used in the method according to claim 1 and the device according to claim 2 is a sensor for reading a bar code, a character or a symbol displayed on the tube surface. 8. The identification device according to claim 2, wherein the switch means is configured to be kept off by an output from the determination means when the determination means determines that the pipe is unsuitable. 9. A second switch means, which is turned off by an output from the determining means when the determining means determines that the pipe is unsuitable, is provided in series with the switch means.
The described pipe identification device. 10. The pipe identifying device according to claim 2, further comprising display means for displaying the determination result by the output from the determination means. 11. A plastic pipe used in a pipe identifying device according to claim 6, wherein magnetic powder or metal powder such as iron powder is added to or embedded in the surface layer or surface. 12. The method for producing a plastic pipe according to claim 11, wherein the metal powder such as magnetic powder or iron powder is added or buried during pipe molding.