JP2843894B2 - How to connect plastic tubes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to, for example polyethylene
The present invention relates to a method for connecting plastic pipes by connecting plastic pipes to each other by using a plastic pipe joint and welding the pipe joint to the plastic pipe.

[0002]

Conventionally, electrostatic the inner peripheral portion of the plastic pipe fittings
Embed the heating wire and connect the connector pins to both ends of the heating wire.
Energize this with plastic pipe fittings
In this case, the plastic pipe joint is melted to connect the plastic pipes to each other (for example, JP-A-1-114419).

[0003] In this type of plastic pipe joint, a pair of plastic pipes to be connected are inserted into both ends of a plastic pipe joint, and then a current is applied to a heating wire through a connector pin to cause the heating wire to generate heat. Is melted to connect the plastic tubes to each other . At this time, leave a constant voltage or current respectively, and each of the plastic fittings, plastic tube and positive connecting
A method of setting the energizing time according to the ambient temperature of the tick pipe joint is generally adopted.

[0004] However, when the temperature of the plastic pipe joint and the plastic pipe is different from the ambient temperature, when the electric resistance error of the heating wire or the current or voltage of energization fluctuates,
Or, it is difficult to set an optimal energizing time when there is an influence of the magnitude of the clearance based on the dimensional error between the outer diameter of the plastic pipe and the inner diameter of the plastic pipe joint .

For this reason, as shown in FIG. 6, the temperature of the plastic pipe joint 2 is measured inside the plastic pipe joint 2 into which the ends of the pair of plastic pipes 1 and 1 to be connected are inserted. The temperature sensor 3 is mounted, and the heating wire 4 embedded in the inner peripheral surface of the plastic fitting 2 is connected to the controller 5.
A temperature of the plastic fitting 2 generated when a predetermined current flows through the connector 6 and 6 and the connector pins 7 and 7 and heated is detected by the temperature sensor 3, and the temperature of the plastic fitting 2 becomes a predetermined temperature. When the heating wire 4
There have been developed ones in which the power supply to the power supply is stopped (see, for example, JP-A-63-99927 and JP-A-6-99927).
0-198224).

Although not shown , the temperature sensor is mounted at two locations of the plastic pipe joint, and when the average value of the two reaches a predetermined temperature, the power supply to the heating wire is stopped. Has also been developed.

[0007]

However, in the above-mentioned conventional example, in the former case, the plastic pipe joint and the ambient temperature
If the degree is different or the outer diameter of the plastic tube and the plastic
The size of the clearance based on the dimensional error of the inner diameter of the pipe joint
It is difficult to set the optimal energizing time when
Was. In the latter case, if there is a connection error or the like in the temperature sensor, even if the plastic fitting reaches a predetermined temperature, it cannot be detected, or it takes too long to detect, and the current flows for a long time. There was a problem that the plastic pipe joint was softened.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide an apparatus which can reliably detect that a plastic pipe joint has reached a predetermined temperature and can stop energizing a heating wire.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is to insert an end of a plastic pipe into a plastic pipe joint in which a heating wire is embedded in an inner peripheral portion, and insert the plastic pipe into the pipe joint.
Insert a temperature sensor into the provided temperature measurement hole and measure the temperature of the plastic pipe joint when energizing the heating wire.
And, in the connection method for a plastic tube to stop energization when the measured temperature has reached the set temperature, to the heating wire
Before turning on the power, measure the temperature of the plastic
Judge whether the temperature change is large or not.
Detects the temperature at which the temperature has decreased as the initial temperature of the joint
Then, the energization completion temperature is set based on the detected initial temperature.
And measuring the temperature of the plastic pipe joint when energizing the heating wire over at least two places of the joint ,
When any one of the measured values reaches the previously set energization completion temperature, the energization is stopped.

[0010]

According to the present invention, the initial temperature of a joint before energization is detected.
Is detected waiting for the temperature change to converge.
Eliminates the effects of the heat of the temperature sensor itself and the heat around the joint.
Detects the initial temperature of the joint
The energization completion temperature is set based on the initial temperature. And
When the heating wire is energized, pipe joints are measured at multiple locations.
When the power supply completion temperature set in the hand temperature is reached
At the point, energization of the heating wire is stopped. For this reason,
Except for failure detection value due to poor connection of temperature sensor, etc.
Energization control is performed based on the joint temperature detected at
Influence of ambient temperature, electric resistance error of heating wire,
If the electric voltage fluctuates, or the inner diameter of the fitting and the outer diameter of the pipe
Related to various conditions during fusion, such as the clearance between
Optimal welding is performed by precise and accurate energization control.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, a heating wire 4 for melting the plastic pipe joint 2 by applying a current is spirally formed on the inner peripheral surface of the plastic pipe joint 2 into which the ends of the plastic pipes 1 and 1 to be connected are inserted. The connector pins 7 are connected to both ends of the heating wire 4. By connecting the connectors 6 and 6 of the controller 5 to the connector pins 7 and 7,
The plastic pipe joint 2 is fused to the plastic pipes 1 and 1 by the heat generated by the heating wire 4 and the plastic pipes 1 and 1 are connected . At this time, the temperature of the plastic pipe joint 2 when the heating wire 4 is energized is measured by the two temperature sensors 3 and 3.

That is, on the outer peripheral surface of the plastic pipe joint 2 near the connector pins 7, 7, two measurement holes 2a,
2a, while connectors 6, 6 of the controller 5 are provided.
The measuring hole when connecting the 6 to connector pins 7,7
2a, 2a are provided with temperature-sensitive sensors 3, 3 each formed by an electric thermocouple.

[0014] Thereby, simultaneously with energizing the heating wire 4,
The temperature of the plastic pipe joint 2 is measured by the two temperature sensors 3, 3. At this time, one of the measured values of the two temperature sensors 3, 3 is set in the controller 5 in advance. When the temperature reaches the temperature, the power supply to the heating wire 4 is stopped.

As described above, the temperature of the plastic pipe joint 2 is measured by the temperature-sensitive sensors 3 and 3, and when one of the measured values reaches the set temperature, the energization of the heating wire 4 is stopped.
It is possible to eliminate the difficulty of setting the optimal energizing time and to prevent excessive current flow when one temperature-sensitive sensor 3 has a connection error.

That is, as shown in FIG. 2, although the optimum energization time varies depending on the outside air temperature, the set temperature is kept constant (for example, 135 ° C.), and the temperature measured by the temperature-sensitive sensors 3 By stopping the energization to the heating wire 4 when the set temperature is reached, the energization time can be corrected according to the outside air temperature, thereby eliminating the difficulty of setting the energization time.

As shown in FIG. 3, even if one of the temperature sensors 3 has a connection error or the like, and this temperature rise does not reach the set temperature with a delay as shown by a dashed line, the influence is not affected. Without receiving any electric current, the other temperature sensor 3 connected normally detects that the plastic fitting 2 has reached the set temperature without fail and stops the supply of electric power to the heating wire 4. Control can be performed.

The flowchart at this time is shown in FIGS.
This will be described below.

First, when the power is turned on, the time display is reset and the mounting lamp is turned on. And two
Connectors 6 and 6 of the connector body 2
When connected to 7, the connector mounting lamp is turned off and the power is turned on.
The connection lamp turns on.

Next, the energizing button is turned on to blink the energizing lamp, and it is determined whether or not the temperature sensors 3 and 3 are disconnected. If there is a disconnection, both the abnormal lamp and the high-pitched buzzer are turned off. Turn ON and output OFF. Also, judge whether the temperature change is large or not and wait until the temperature change becomes small.
Is done. That is, if the temperature change is large, the sensor
The determination of nothing and a temperature change is repeated. This has become rather small
Then, the initial temperature is detected, and the energization completion temperature (set temperature) is set and stored in the memory. This is a sensor
The temperature of 3,3 is actually affected by the heat received in the previous welding operation
To prevent detection at temperatures higher than the joint temperature.
This is because the current completion temperature (set temperature) differs depending on the wrong initial temperature of the joint .

Then, the output is turned on, and a time counter,
After turning on both the energizing lamp and the low-pitched buzzer, whether or not the temperature sensors 3 and 3 are disconnected, whether or not the heating wire is short-circuited, whether or not the output voltage is abnormal, and whether or not the temperature rises It is sequentially determined whether or not there is, and if they are present, the abnormal lamp and the high-pitched sound buzzer are both turned on and the output is turned off. When one of the two temperature sensors 3 and 3 reaches a set temperature (completion temperature) on condition that the reset button is not turned on, the output is turned off.
To

Next, the circuit and the energizing lamp are both turned off, the bass buzzer is turned off, and the cooling lamp is turned on.
After 55 seconds have passed since the output was turned off, the joint was removed, the joint removal lamp and the connection lamp were both turned off, and then the abnormal lamp, treble buzzer and cooling lamp were both turned off to connect the plastic pipes 1 and 1. Complete. Here, when 55 seconds have not passed since the output was turned off and the joint was not removed, the reset button
Under the condition that N has been reached, both the abnormal lamp and the high-pitched sound buzzer are turned off, and wait for 55 seconds to elapse.

In the above embodiment, a thermocouple is used as each of the temperature sensors 3 and 3. However, a thermistor or a temperature resistor can be used. Of course, any number of two or more may be used.

[0024]

As is apparent from the above description, according to the present invention, it is possible to eliminate the difficulty of setting the conventional energizing time, and
Excitation temperature of the hand is correct except for the effect of heat other than the joint.
The temperature of the joint during energization is set at multiple locations.
Measured over time and based on the detected value that reached the set temperature first
Since energization control is performed, such as sensor connection failure to the joint,
Accurate inspection except for defective detection values due to various conditions during fusion
Since the energization control is performed at the output temperature,
Moreover, accurate fusion is performed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view for explaining one embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a temperature sensor based on a difference in outside air temperature and an energization time.

[Figure 3] temperature-sensitive cell when there is an abnormality in one temperature-sensitive sensor
6 is a graph showing a relationship between a sensor temperature and a current supply time.

FIG. 4 is a flowchart in FIG. 1;

FIG. 5 is a flowchart in FIG. 1;

FIG. 6 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Plastic pipe 2 Plastic pipe joint 3 Temperature sensor 4 Heating wire 5 Controller

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16L 47/02

Claims (1)

(57) [Claims] 1. An end portion of a plastic pipe is inserted into a plastic pipe joint in which a heating wire is embedded in an inner peripheral portion thereof, and the heat pipe is inserted into the pipe joint.
Insert a temperature sensor into the provided temperature measurement hole and measure the temperature of the plastic pipe joint when energizing the heating wire.
And, in the connection method for a plastic tube to stop energization when the measured temperature has reached the set temperature, to the heating wire
Before turning on the power, measure the temperature of the plastic
Judge whether the temperature change is large or not.
Detects the temperature at which the temperature has decreased as the initial temperature of the joint
Then, the energization completion temperature is set based on the detected initial temperature.
And measuring the temperature of the plastic pipe joint when energizing the heating wire over at least two places of the joint ,
A method of connecting a plastic pipe, wherein the current supply is stopped when any one of the measured values reaches the previously set power supply completion temperature.