JP2638112B2 - Apparatus and method for controlling electrofusion - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus and a method for electrofusion, and more particularly to a control apparatus and a method for energizing a joint in which a heating wire is embedded and comprising a synthetic resin such as PE, PP or EPPB. For example, the present invention relates to a control device and a method for controlling an energizing time when a conduit for gas or water (hereinafter referred to as a “synthetic resin conduit”) and its joint are fused.

(Prior art)

Conventionally, such a joint for electro-fusion (Electo-Fusion) has a heating wire embedded in the inner wall of the end,
After fitting the synthetic resin conduit to the joint, the heating wire is energized to generate heat, and the two are fused and joined (fused).
In such EF joints, it is complicated to change the type of heating wire (resistivity or specific resistance) depending on the diameter of each pipe, and therefore the length of the heating wire, that is, the resistance value differs depending on the pipe diameter of the fitting. . On the other hand, for good fusion, it is necessary to appropriately melt both the joint and the synthetic resin conduit.Therefore, considering the difference in the resistance value, the time for energizing the heating wire according to the pipe diameter is reduced. You need to control.

Various examples of such time control methods include, for example,
Japanese Patent Application Laid-Open No. 58-131025 filed on Aug. 4, 1983
No., Japanese Unexamined Patent Publication No. 60-19, filed on Oct. 7, 1985.
No. 8224 or Japanese Patent Application Laid-Open No. 61-274920 published on Dec. 5, 1986.

The first prior art adds a recognition resistor having a different resistance value for each different pipe diameter, recognizes the resistance value of the recognition resistor, and sets a predetermined time in a counter in accordance with the added value. This controls the power distribution time.

In the second related art, a molten state is detected by a sensor, and when the molten state becomes a predetermined state, the energization is cut off.

The third conventional technique is to compare the current level flowing to the tax office with the current level of each pipe diameter which is known in advance, and control the entire energizing time by comparing the current levels.

[Problems to be solved by the invention]

The first and third prior arts focus on the electrical characteristics of a heating wire and perform energization time control according to the electrical characteristics.
The second conventional technique is to control the energization time by focusing on the volume change during melting. In the first and second prior arts, it is necessary to add a special recognition resistor or sensor, and the production of a synthetic resin conduit or a joint becomes complicated. On the other hand, in the third prior art, such an additional device can be omitted, but it is necessary to compare current levels before full-scale energization, which complicates control.

[Means for solving the problem]

SUMMARY OF THE INVENTION One of the present invention, in brief, is a control device for electrofusion between a joint in which a heating wire is embedded and a synthetic resin conduit, for generating a power supply to be applied to the heating wire. Power generation means, type data input means for inputting the type of joint, storage means for presetting control data including duty ratio and energizing time for each type of joint, type provided from the type data input means Data output means for outputting data of the duty ratio and the energization time based on the control data read from the storage means in accordance with
And an intermittent means for intermittently intermittently turning on and off the power supply of the power supply means in accordance with the duty ratio during the energization time.

Another aspect of the present invention is a control method for electro-fusing a joint in which a heating wire is buried and a synthetic resin conduit. And control data including the energizing time are set in the storage means in advance, and (b) type data representing the type of the joint is input;
(C) outputting duty ratio and energization time data based on the control data read from the storage means in accordance with the type data; and (d) electrically welding the power supply repeatedly according to the duty ratio during the energization time. It is a control method.

[Action]

For example, a bar code label attached to each joint is read by a light pen, and, for example, type data such as a pipe type and a pipe diameter is input. For example, a storage means such as a microcomputer ROM stores, for each type of joint,
Control data including the duty ratio of the power supply to be applied to the heating wire and the entire energizing time are set in advance. When the type data is input as described above, the data output unit reads out the data of the duty ratio and the energization time corresponding to the type from the storage unit, and changes the data as necessary (for example, the environmental temperature). ), And outputs data of the duty ratio and the energization time. Then, for example, the interrupting means such as a microcomputer repeatedly interrupts the power from the power generating means in accordance with the duty ratio output from the data output means during the energization time output from the data output means. Therefore, the duty ratio of the power supply applied to the heating wire of the joint and the entire energizing time are controlled. When the power supply is AC, not only the entire energizing time but also the number of cycles per unit time is controlled. In the case of DC, the duty ratio and the energization time are similarly controlled.

〔The invention's effect〕

According to the present invention, since the duty ratio of the power supply applied to the heating wire of the joint and the entire energization time are controlled, even if the resistance value of the heating wire of each joint is different, the optimum value is obtained for the resistance value. , And therefore, it is possible to reliably and efficiently perform electrofusion.

Moreover, it is only necessary to input the type data of the joint such as the pipe type and / or the pipe diameter.
It is not necessary to provide any additional means for the joint or the conduit made of synthetic resin, and it is possible to avoid complicated control.

Other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the accompanying drawings.

〔Example〕

With reference to FIG. 1, a fusion control device 10 according to one embodiment of the present invention includes a housing 12, and a power switch 16 is provided on a front panel 14 of the housing 12. On the front panel 14,
A pipe type display section 18 is formed, and the pipe type indicator 18 has an LED 20 on which different pipe diameters (nominal diameters) of different pipe types are displayed.
a, 20b,...

On the front panel 14, a connector 22 is further provided,
As shown in FIG. 2, a light pen 28 (FIG. 3 or FIG. 6) for reading a bar code label 26 attached to the joint 24 is connected to the connector 22. The pipe type displayed on the barcode label 26 read by the light pen 28 is the LED 20a, 20b,.
.. Is displayed by lighting the corresponding one of.

Between the pipe type indicator 18 and the connector 22, an energization time indicator 30, an abnormality indicator 32 and an operation indicator 34 are arranged.
The energization time display 30 is for displaying the energization time and the remaining time determined as described later, and is, for example, a two-digit segment display. The abnormality indicator 32 includes display LEDs 36a, 36b, 36c and 36d,
The EDs 36a, 36b, 36c and 36d are respectively referred to as “power supply voltage”,
Displays “output voltage”, “disconnection” and “overcurrent”. The operation indicator 32 includes two display LEDs 38a and 38b. The display LED 38a indicates the operation (RUN), and the display LED 38b indicates the operation end (END).

A start switch 40 provided with the operation indicator 32 is a switch for instructing the start of energization, and a stop switch 42 is a switch for forcibly stopping energization.

An upper portion of the front panel 14 is formed as a storage section 44, which stores, for example, a power cord, an output code, a light pen, and the like (not shown).

Joints to which the present invention can be applied include “sockets”,
There are various things such as "cheese", "elbow", "cap", "saddle" or "reducer". FIG. 2 shows a socket as an example. The joint 24 has a connection end 46 into which a connection end 50 of a synthetic resin conduit 48 is inserted. On the inner wall of the connection end 46 of the joint 24, as shown by a dotted line,
A heating wire 52 is embedded, and this heating wire 52
Is connected to the terminal 54 at the outer periphery of the terminal. An output cord 56 of the apparatus shown in FIG. 1 is connected to the terminal 54 so that the heating wire 52 can be energized.

The outer periphery of the joint 24 is further provided with a barcode label as described above.
On the bar code label 26, unique information of the joint 24, such as a pipe type and a pipe diameter, is displayed as a bar code so that it can be read by the light pen 28.

In this embodiment, even if the type of the joint or the pipe diameter is changed, the production is not complicated, so that all heating wires having the same resistivity or specific resistance are used. Therefore,
The resistance value of the entire heating wire 52 differs depending on each joint. Therefore, in this embodiment, control is performed so that the energization time is optimized according to each joint.

With reference to FIG. 3, the fusion control device 10 is
A power supply terminal 58 for receiving a power supply of 100 V is provided, and 100 V AC from this power supply terminal 58 is applied to a constant voltage circuit 60 of 24 V DC, for example. The constant voltage circuit 60 includes a well-known transformer, an inverter circuit, and the like.
Generates 24 VDC. The output voltage from the constant voltage circuit 60 is intermittently controlled by the switching transistor 62 and is led out to the output terminal 64.

An input voltage detection circuit 66 including, for example, a CT (Current Transformer) is provided so that an input voltage from power supply terminal 58 can be detected. Input voltage detection circuit 66 has an input voltage having a specified value, for example, 85V to 135V. , The signal is output and given to the microcomputer 68. In addition, an overcurrent detection circuit 70 is provided in association with the constant voltage circuit 60. The overcurrent detection circuit 70 outputs a signal when the output current exceeds a certain specified value, for example, 15 A during fusion, and outputs a signal. Give to computer 68. In addition, a constant voltage circuit
An output voltage detection circuit 72 is provided at the output of the circuit 60. The output voltage detection circuit 72 outputs a signal when the output voltage from the constant voltage circuit 60 exceeds a predetermined value, for example, 24 V ± 2%. To the microcomputer 68. A disconnection check transistor 74 is interposed between one of the outputs of the constant voltage circuit 24 and the output terminal 64, and a disconnection output circuit 76 is connected to the output of the disconnection check transistor 74. . This disconnection detection circuit 76 includes a resistor associated with the circuit 76.
As described above, it is determined whether or not the terminal 54 of the joint 24 to which the output cord 56 is connected, that is, whether or not the heating wire 52 is disconnected, based on the voltage of 76a. If the heating wire 52 is disconnected, the disconnection detection circuit 76 outputs a signal and supplies it to the microcomputer 68.

In the microcomputer 68, these abnormality detection circuits 6
When an abnormal condition is detected by 6, 70, 72 and 76,
As described later, for example, the output from the constant voltage circuit 60 is stopped, and the corresponding one of the display LEDs 36a to 36d of the abnormality indicator 32 is turned on.

A light pen 28 is connected to the connector 22 (FIG. 1), and an output signal of the light pen 28 is transmitted to a bar code reading circuit.
Given to 78. The barcode reading circuit 78 is a light pen
The signal from 28 is decoded, converted to "1" or "0", and supplied to the microcomputer 68. Therefore, the microcomputer 68 receives data of the pipe type and the pipe diameter of the joint 24 displayed on the barcode label 26.

Although not shown in FIG. 1 above, a temperature sensor 80 including, for example, a thermistor is provided in the housing 12, and the temperature sensor 80 detects the environmental temperature in which the device 10 is installed. Then, the voltage signal from the temperature sensor 80 is supplied to the temperature detection circuit 82, where it is converted into digital data and supplied to the microcomputer 68. In accordance with the environmental temperature measured by the temperature sensor 80, the microcomputer 68 sets the display LE included in the temperature display 84 shown in FIG.
D86a, 86b or 86c is turned on, and the energization time is modified (increased or decreased) as described later.

The start switch 40 and the stop switch 42 described above are connected to the microcomputer 68,
Various outputs 18, 30, 32 and 34 shown in FIG. 1 and a temperature display 84 described later are connected to the output.

5A to 5C, the main routine of FIG. 5A is started in response to turning on of power switch 16. In the first step S1 of the main routine, the microcomputer 68 controls the display LEDs, the energization time display 30, etc.
Initialize the I / O ports and registers associated with it.

Subsequently, when a barcode input is given from the barcode reading circuit 82 in step S3, the microcomputer 68 reads the temperature data from the temperature detecting circuit 82 in the next step S5.

In the following step S7, the microcomputer 68
Set O data. Specifically, based on the barcode input data and the temperature data, the duty ratio, the energization time, and the like are set in a register.

For example, as shown in the following Table 1, the standard time and the duty ratio (unit time, for example, the energization / interruption time ratio repeated for one second) for each pipe type displayed on the pipe type indicator 18 in FIG. It is stored in a ROM (not shown) of the microcomputer 68.

In the above table, the duty ratio D or the time T
May be different for each joint, or may be common to multiple types or pipe diameter joints.

In any case, depending on the temperature, + Dα, 0 or -D
α is added to the duty ratio D in the above table. Assuming that the standard duty ratio D of a certain joint is, for example, “50” and the correction duty ratio Dα is, for example, “10”, when the environmental temperature is, for example, 0 ° C. or less, the duty ratio is “60” (= D +
Dα = 60 + 10). For example, if the environmental temperature is 0
When the temperature is between 30 ° C. and 30 ° C., the duty ratio is “50” (= D + D
α = 50 + 0), and when the environmental temperature is, for example, 30 ° C. or higher, the duty ratio “40” (= D + Dα = 50−
Set as 10).

Further, + Tα, 0 or −Tα is added to the standard time T in the above table depending on the temperature. Assuming that the standard energizing time T of a certain joint is, for example, 16 seconds and the correction time Tα is, for example, 5 seconds, when the environmental temperature is, for example, 0 ° C. or less, the energizing time is set to 21 seconds (= T + Tα = 16 + 5). . When the ambient temperature is, for example, 0 ° C to 30 ° C,
Second (= T + Tα = 16 + 0), and when the ambient temperature is, for example, 30 ° C. or higher, the energizing time is set to 11 seconds (= T + T
α = 16−5).

When the start switch 40 (FIG. 1) is pressed in the next step S9 with the duty ratio D and the energizing time T set in this way, the microcomputer 68 executes the cycle timer control in the next step S11. Do.

That is, the microcomputer 68 responds to the duty ratio D and the energizing time T set as described above,
Interrupt the control signal to that output port. Since this control signal is amplified and applied to the base of the switching transistor 62, the switching transistor 62 is repeatedly turned on / off in accordance with the set duty ratio D, and is kept on / off for the set energizing time T. .
Therefore, according to this embodiment, an intermittent voltage of, for example, 24 VDC as shown in FIG. 4 is applied to the heating wire 52 (FIG. 2) of the joint 24 from the fusion control device 10.

In this way, if not only the energization time but also the duty ratio is controlled, the optimal energization control can be performed for each tube diameter of each type. That is, in a joint having a small pipe diameter, the duty ratio is relatively small, but if the energization time is controlled so as not to be too short, rapid heating when the pipe diameter is small is suppressed. More specifically, in a joint with a small pipe diameter, if the same heating wire is used as in the case of a large pipe, the overall resistance value will be small, and when the same amount of power is applied, the current will increase and the heating will be rapid. . When the joint is rapidly heated in this way, the joint melts sufficiently, but not enough heat is transmitted to the synthetic resin pipe to be joined thereto, and the melting remains insufficient. In this case, of course, poor fusion results. On the other hand, in the case where the overall resistance value is small as in this embodiment, if not only the energization time but also the duty ratio is reduced, defective fusion caused by insufficient fusion can be effectively prevented. . Further, when the overall resistance value is large, if the duty ratio is increased and the energizing time is lengthened,
A sufficient amount of heat can be obtained in a shorter time, which is preferable in terms of working efficiency.

Further, if the duty ratio and / or the energization time are changed depending on the environmental temperature, reliable fusion can be performed regardless of the environmental temperature, that is, regardless of the existing temperature.

Returning to FIG. 5A, in step S13, the fifth
When an abnormality signal is output in the abnormality detection routine shown in FIG. B or a stop signal is output, for example, when the stop switch 42 is pressed, the control is stopped as it is.
Then, in step S15, when the barcode data is input again for another fusion, the previous steps S5 to S1
Step 3 is repeated, and when all terminations are instructed in step S17, the main routine is terminated.

It should be noted that the abnormality detection routine shown in FIG. 5B can be easily understood and is not important for the present case, so that detailed description is omitted.

FIG. 6 is a block diagram showing another embodiment of the present invention. This embodiment is intended to control the duty ratio and the energizing time of the AC voltage, while the embodiment of FIG. 3 performs the intermittent operation of the DC voltage.

That is, provided by a 50 or 60 Hz commercial power supply 84
AC100V is stepped down by the transformer 86 and output as AC24V.

On the primary side of the transformer 86, for example, "OMRON G3A-2
A thyristor circuit 88 such as 0B "is inserted, and this thyristor circuit 88 is controlled by a control circuit 90.

The control circuit 90 includes a power supply circuit 92.
5V DC is generated from 100V and supplied to each circuit of the control circuit 90. An input voltage detection circuit 94 is also coupled to the primary side of the transformer 86, and this input voltage detection circuit 94, like the input voltage detection circuit 66 of the previous embodiment (FIG. 3), has an unusual 100 VAC voltage. Detect fluctuations. An output voltage detection circuit 96 and a disconnection detection circuit 98 are coupled to the secondary side of the transformer 86. Each of these circuits 96 and 98 also detects an abnormal output voltage and a disconnection of the heating wire 52 (FIG. 2) of the joint 22, similarly to the output voltage detection circuit 72 and the disconnection detection circuit 76 of the previous embodiment. Then, the input voltage detection circuit 94 and the output voltage detection circuit 96
The respective detection outputs of the disconnection detection circuit 98 and the disconnection detection circuit 98 are supplied to the abnormality detection circuit 100, and the abnormality detection circuit 100 supplies an abnormality signal to the thyristor drive circuit 102. Thyristor drive circuit 1
02, when receiving the abnormal signal, controls the thyristor circuit 88 to deactivate it.

The thyristor drive circuit 102 includes a start / stop circuit 104 connected to the start switch 40 and the stop switch 42.
It is started in response to a start signal from, and is stopped in response to a stop signal.

Further, the barcode reading circuit 106 receives a read signal of the barcode label 26 (FIG. 2) from the light pen 24 and decodes it. Then, based on the result of the decoding, the barcode reading circuit 106 supplies the data representing the pipe type and the pipe diameter to the duty ratio / time setting circuit 108 as described above. In the duty ratio / time setting circuit 108, based on the given data, the duty ratio and energization time preset for the pipe type and pipe diameter are known,
In response, the data of the duty ratio is given to the thyristor drive circuit 102 described above. Therefore, the thyristor drive circuit 102 generates a drive signal based on the provided data, and controls firing of the gate of the thyristor included in the thyristor circuit 88.

At this time, the temperature detection circuit 110 connected to the thermistor 80 supplies data on the grounded environmental temperature of the device 10 at that time to the thyristor drive circuit 102.
Therefore, the thyristor drive circuit 102 modifies or changes the set duty ratio depending on the temperature in the same manner as described above, and controls the thyristor circuit 88 with the changed duty ratio. Therefore, according to this embodiment, an intermittent voltage of 24 V AC is output from the output terminal 64 as shown in FIG. That is, when the AC power is applied as described above, if the duty ratio is controlled, the number of cycles (the number of repetitions) per unit time is controlled.

Further, the timer time is set in the timer circuit 112 by the time data from the duty ratio / time setting circuit 108, and this timer time is also modified or changed according to the above-mentioned temperature data. Then, the timer circuit 112 displays the timer time on the display 30.

Then, based on the data from the barcode reading circuit 106, the display setting circuit 114 causes the tube type display LEDs 20, 2 shown in FIG.
0b,..., Controls the lighting of the LED group including the LEDs 36a to 36d and 38a and 38b.

Also in this embodiment, the duty ratio of the power supply applied to the heating wire 52 and the energization time are controlled, so that the fusion can be performed reliably and efficiently regardless of whether the diameter is small or large.

Table 2 shows the results of the fusion experiment according to this example. In the experiment, an adapter with a male thread having a pipe diameter of φ8 was used.

In the above table, the results are the results of a 90 ° C. hot internal pressure creep test, and the test pressure was 22 kg / cm ² . And in sample 1, without controlling the number of cycles, 60 Hz per second,
That is, application was performed at a duty ratio of “100”. As a result, in Sample 1, leakage occurred. On the other hand, the sample 2 was applied to the apparatus at a duty ratio of "33" (cycle number 20), and the sample 3 was applied to the apparatus at a duty ratio of "8" (cycle number 5). As a result, in Samples 2 and 3, 1000
No abnormalities occurred for more than an hour. As described above, even if the total amount of heat is almost the same, the result shows a great difference if the duty ratio is not changed, and the effectiveness of this embodiment is proved.

In the embodiment shown in FIG. 6, a microcomputer may be used for control as in the embodiment shown in FIG. 3, and in the embodiment shown in FIG. You may comprise using a circuit.

Furthermore, switching means for interrupting the power supply include:
Any means other than the switching transistor 62 in FIG. 3 and the thyristor circuit 88 in FIG. 6 may be used.

In the above-described embodiments, a bar code label and a light pen are used as input means. However, various modifications are possible, for example, by configuring the LEDs 2a, 20b,... Shown in FIG. 1 as switches with lamps, and allowing the user to selectively press them according to the pipe type and pipe system. Will.

[Brief description of the drawings]

FIG. 1 is an illustrative view showing an arrangement of a front panel in one embodiment of the present invention. FIG. 2 is a perspective view showing an example of a joint to which the present invention can be applied. FIG. 3 is a block diagram showing an example of the configuration of the fusion control device shown in FIG. FIG. 4 is an illustrative view showing one example of an output voltage waveform according to the embodiment of FIG. 5A and 5B are flow charts showing the operation of the FIG. 3 embodiment. FIG. 6 is a block diagram showing another example of the configuration of the fusion control device shown in FIG. FIG. 7 is an illustrative view showing one example of an output voltage waveform according to the embodiment of FIG. In the figure, 10 is a welding control device, 24 is a joint, 26 is a bar code label, 28 is a light pen, 50 is a constant voltage circuit, 62 is a switching transistor, 68 is a microcomputer,
78 is a bar code reading circuit, 80 is a temperature sensor, 82 is a temperature detection circuit, 88 is a thyristor circuit, 102 is a thyristor drive circuit, and 108 is a duty ratio / time setting circuit.

Continuation of front page (72) Inventor Takachi Harada 64 Ishizukita-cho, Sakai City, Osaka Prefecture Kubota Iron Works Co., Ltd. Vinyl pipe plant (56) References JP-A-56-501593 (JP, A) JP-A-58-131025 (JP, A) JP-A-63-160822 (JP, A) French publication 2572326 (FR, A1)

Claims (3)

(57) [Claims] 1. A control device for electro-fusing a joint in which a heating wire is buried and a synthetic resin conduit, wherein a power generating means for generating a power to be applied to the heating wire, Type data input means for inputting a type of a joint; storage means for presetting control data including a duty ratio and an energizing time for each type of the joint; in accordance with the type given from the type data input means Data output means for outputting duty ratio and energization time data based on the control data read from the storage means, and the power supply of the power supply generation means is repeatedly turned on and off in accordance with the duty ratio during the energization time Control device for electric fusion, comprising an intermittent means for the operation. 2. A temperature detecting means for detecting an environmental temperature, wherein the data output means changes at least one of the duty ratio and the entire energizing time according to the temperature detected by the temperature detecting means. The control device for electrofusion according to claim 1, comprising means. 3. A control method for electrically fusing a joint in which a heating wire is buried and a synthetic resin conduit, wherein: (a) control data including a duty ratio and an energizing time for each type of the joint; (B) inputting type data representing the type of the joint, and (c) determining the duty ratio and the energizing time based on the control data read from the storage means in accordance with the type data. (D) a method of controlling electrofusion wherein the power supply is repeatedly turned on and off in accordance with the duty ratio during the energization time.