JP2962999B2 - Control method of energization of electric fusion joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for connecting a pipe made of a thermoplastic resin and a pipe joint by electrofusion and, more particularly, to supplying a predetermined electric power to a heating wire provided in the pipe joint. The present invention relates to a power supply control method for stopping power supply.

[0002]

2. Description of the Related Art Conventionally, a method of controlling an energizing time for supplying a predetermined electric power to a heating wire provided in a pipe joint is disclosed in, for example,
There is an apparatus disclosed in Japanese Unexamined Patent Publication No. 27014/1990. Before supplying power to the heating wire of the fitting, a small current is applied to detect the value of the current flowing through the heating wire, and from this current value, the size of the fitting is identified and power is supplied according to the size of the fitting. On the other hand, the time is determined, and on the other hand, the initial temperature of the fitting surface is detected, and the power supply time previously detected is adjusted and changed from the initial temperature to determine the total time of the power supply. It will stop.

That is, control is performed to determine the power supply time from the initial temperature of the joint and the joint dimensions. Then, the initial temperature of the fitting is detected by connecting the socket to the fitting connector pin by using a temperature sensor provided at the socket at the end of the cable of the fusion device to be connected to the connector pin of the fitting. Detected.

[0004]

In the above prior art, the energizing time to the heating wire is determined from the environmental temperature at the time of fusion, that is, the initial temperature of the pipe joint and the diameter of the pipe joint. The diameter of the pipe joint is determined from the value of the current flowing to the heating wire. However, in the actual welding operation, the fitting state of the pipe and the fitting varies, and the pipe and the fitting may not fit together due to the difference in the inner and outer diameters of the pipe and the fitting, the flatness of the pipe, and when bending force is applied to the pipe. The circumference of the fusion joint between the pipe joints does not become a uniform gap, and the degree of adhesion differs. Therefore, if the control of the power supply is stopped only by the time based on the initial temperature and bore size of the pipe joint, the fused part will be excessively melted, causing inconvenience in the pipe or the pipe joint or insufficient melting. Or cause insufficient fusion.

Also, in order to identify the size of the pipe joint from the value of the current flowing through the heating wire, even if the diameter of the pipe joint is different from that of a same-diameter socket and a different-diameter socket, for example, the resistance of the heating wire is not small. Since there is no difference in the value of the flowing current, the size identification is erroneously recognized. In particular, as the diameter increases, the fusion area between the joint and the pipe increases, and a large current needs to flow. However, when there is a limit to the current that can be passed as in a general commercial AC 100 V power supply, the resistance value of the heating wire is limited, and the larger the diameter, the smaller the difference between the resistance value and the diameter. Therefore, as the diameter increases, it becomes more difficult to identify the diameter based on the difference in current value. The present invention solves the above-mentioned problems, and can reliably identify dimensions of a large-diameter pipe joint with a small difference in current value, and furthermore, in addition to the joint dimensions and the environmental temperature at the time of fusion, fitting of the pipe to the pipe joint. An object of the present invention is to provide a control method capable of controlling the stop of energization without causing excessive fusion or insufficient fusion in consideration of the combined state.

[0006]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a pipe joint made of a thermoplastic resin having a heating wire provided on an inner peripheral surface thereof,
When the pipe made of a thermoplastic resin inserted into the inner peripheral surface of the pipe joint is fusion-spliced by supplying a predetermined power to the heating wire and electrically energizing and heating, it is detected while the heating wire is energized. The temperature rise rate is determined from the temperature of the pipe joint obtained, the dimension of the pipe joint is identified from the temperature rise rate, and the power supply stop time for stopping power supply to the heating wire is controlled in accordance with the dimension. This is a method for controlling the energization of the joint.

Further, a temperature sensor is attached to the pipe joint, an initial temperature of the pipe joint is detected by the temperature sensor, and an energization stop temperature at which the energization to the heating wire is stopped is obtained from the initial temperature. The heating rate is determined from the temperature of the fitting detected during energization, the dimensions of the fitting are identified based on the heating rate, and the energization stop time for stopping energization of the heating wire is determined according to the dimension. This is a method for controlling power supply to the electrofusion joint, wherein power supply to the heating wire is controlled from both the temperature and the power supply stop time.

Further, a temperature sensor is mounted on the pipe joint, an initial temperature of the pipe joint is detected by the temperature sensor, and a first power supply stop temperature for stopping power supply to the heating wire from the initial temperature (shown in FIG. 7). T1) and a second energization stop temperature (T2 shown in FIG. 7) set to a value equal to or lower than the first energization stop temperature, and a heating rate is obtained from the temperature of the pipe joint detected while energizing the heating wire, The size of the pipe joint is identified from the rate of temperature increase, and an energization stop time (S1 shown in FIG. 7) for stopping energization of the heating wire is calculated according to the size. Before reaching the calculated energization stop time (S1), Next, when the temperature of the pipe joint while energizing the heating wire reaches the first energizing stop temperature (T1) (FIG. 7).
If the temperature of the pipe joint being energized has reached the second energization stop temperature (T2) when the energization to the heating wire is stopped and the energization stop time (S1) is reached, (Line A shown in FIG. 7) This is a method for controlling the energization of the electrofusion joint, which comprises stopping the energization to the heating wire.

In the above, the power supply stop time (S1)
Is reached, the power is supplied until the temperature of the pipe joint during the power supply fusion reaches the second power supply stop set temperature (T2),
When the second energization stop temperature (T2) is reached (line C shown in FIG. 7), control can be performed so that energization is stopped.
Furthermore, in the above, the final energization stop time S shown in FIG.
2) If the temperature of the pipe joint during energization fusion does not reach the second energization stop temperature (T2) before reaching the final energization stop time (S2) after the energization stop time (S1) (D line shown in FIG. 7) can be controlled so that energization to the heating wire is stopped as a fusion failure.

[0010]

The present invention is configured as described above, and the bore size of the pipe joint is identified by the rate of temperature rise during current welding. Therefore, by changing the mounting position of the temperature sensor to the pipe joint according to the bore size, it is possible to provide a clear difference in the temperature rise rate of the pipe joint depending on the bore size. For this reason, it is possible to accurately identify the diameter of a pipe joint even in a large-diameter pipe having a small difference in resistance value. In addition, energization is controlled from both sides of the energization stop time according to the dimensions of the pipe joint and the temperature of the pipe joint during energization fusion. Therefore, finer control can be performed without causing excessive fusion caused by excessively heating the welded portion between the pipe and the pipe joint and deformation of the welded portion caused by excessively long energization welding time.

When the temperature of the pipe joint reaches the power supply stop temperature first, the power supply is stopped, and when the power supply stop time is reached before reaching the power supply stop temperature, it is determined that the fusion is completed. Since the energization is stopped, the control can be performed in consideration of the fitting state with the pipe inserted into the pipe joint. For example, the fitting state of the pipe and the pipe joint is as shown in FIGS. 6A and 6C, or an elliptical flat pipe is fitted, or as shown in FIGS. 6B and 6D. If a bending force is applied to the pipe in the state and the pipe is deviated to one of the inner peripheral surfaces of the pipe joint, a portion having a close contact portion and a gap is formed on the fitting circumference of the pipe and the joint.

In this case, when the position of the concave hole for detecting the temperature of the pipe joint is at the close contact portion on the fitting circumference as shown in FIGS. Despite the fusion progressing quickly, the heat generated on the pipe joint side moves to the pipe side, so that the temperature in the concave hole decreases, and the line A in FIG.
As described above, the temperature rise rate of the pipe joint becomes slow. On the contrary, FIG.
As shown in (c) and (d), when the position of the concave hole is in the gap on the fitting circumference, heat is generated on the pipe joint side despite the slow fusion between the pipe and the pipe joint in the gap. Since the heat transferred to the tube side is delayed, the temperature of the hollow increases, and the line B in FIG.
As shown by, the temperature rise speed of the pipe joint increases. However, under any of the above conditions (a), (b) or (c) and (d), there is a close contact portion and a gap portion on the circumference, and the heating wire is heated all around the pipe joint. I have.

For this reason, under the conditions (a) and (b), where the temperature is low and the temperature rise is delayed and there is a concave hole in the contact portion, the energization is not stopped by the temperature control as indicated by the line A in FIG. Is performed to prevent the joint and the pipe from being deformed due to insufficient fusion at the gap side of the pipe and the pipe joint opposite to the concave hole position and an excessive energization time. Further, under the conditions (c) and (d) where there is a concave hole in the gap where the temperature detection is high and the temperature rises quickly, the line B in FIG.
As described above, since the power supply is stopped by the temperature control earlier than the time control, excessive fusion of the pipe and the pipe joint close contact portion side opposite to the position of the temperature detection concave hole is prevented. In this manner, uniform fusion splicing between the pipe and the pipe joint without excessive fusion or insufficient fusion is performed.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view of an electrofusion type pipe joint in a state where a resin pipe according to one embodiment of the present invention is inserted, and FIG.
Is shown. In the pipe joint 1 of this embodiment, after the connecting members 11 and 11 are molded one by one, the end surfaces of the connecting members 11 and 11 at the central part side are heated by a heating plate, and then the connecting members 11 are joined together by heat fusion. Is formed.

Openings 13 for receiving the resin pipe 50 are provided at both ends of the pipe joint 1, and the heating wire 2 is helically embedded on the inner peripheral side of the opening 13. The heating wire 2 is connected to terminals 21 and 22 buried on the end side and the center side of the pipe joint 1, and the heating wire 2 and the terminals 21 and 22 are provided at both side openings of the pipe joint 1, respectively. Concave holes 14, 15 for inserting the thermocouple thermometer 6 are provided near the terminals 21, 22,
The progress of the molten state of the pipe joint 1 due to the heating of the heating wire 2 is continuously measured by a thermometer. Reference numeral 16 denotes an indicator hole for visually judging whether the molten resin of the pipe joint rises therein and protrudes from the outer peripheral surface of the joint when connected to the resin pipe, and whether the fusion with the resin pipe 50 has been normally performed. The energizing plug 9 is connected to the thermocouple thermometer 6 and the terminal 2 as shown in FIG.
The socket 8 connected to the terminals 1 and 22 is integrated. The socket 8 is inserted into the terminals 21 and 22 and the front end surface 7 of the thermometer 6 is brought into contact with the bottom surface 17 of the concave holes 14 and 15. In this way, energization from the power supply controller and temperature measurement of the pipe joint are performed.

The thickness of the pipe joint 1 on the center side is larger than the thickness on the end side, and the terminal 22 on the center side and the concave hole 15 for temperature measurement are more peripheral than the terminal 21 and the concave hole 14 on the end side. The concave hole 14 is provided close to the inner peripheral surface of the pipe joint 1, and the concave hole 15 is provided away from the inner peripheral surface of the pipe joint 1. For this reason, the detection temperature of the fusion state of the pipe joint is mainly determined by the temperature detection value of the concave hole 14, and the temperature rise rate of the joint for identifying the diameter of the pipe joint is detected by detecting the temperature of the concave hole 15. Values are used. Therefore, by changing the distance from the inner peripheral surface of the concave hole 15 according to the diameter of the pipe joint, the temperature rise rate of the pipe joint can have a clear difference depending on the diameter of the pipe joint, and accurate diameter discrimination can be performed. .

After the resin tube 50 is inserted into the opening 13 of the pipe joint, when a power source is connected and the heating wire 2 is energized, the resin near the heating wire is melted by the heating of the heating wire, and the melted resin is removed from the resin tube. The outer peripheral surface of the resin tube 50 expands to melt the outer peripheral surface of the resin tube, and fusion with the resin tube is performed. Concave hole 1 for temperature measurement
A thermocouple thermometer 6 is inserted into each of the heating wires 4 and 15 before energization of the heating wire, and the temperature in the concave holes 14 and 15 is measured and fed back to the controller side until the fusion is completed. .

Next, the state of fusion splicing, the control of the electric fusion controller for controlling the energization of the heating wire 2 and the display of the controller will be described with reference to FIGS. FIG. 4 shows a display panel of a controller equipped with a microcomputer. The display panel has a function of inputting by a panel switch and displaying by a display lamp. FIG. 5 is a flow chart showing the operation of the controller, and S1, S2,. Hereinafter, description will be made according to this flow. (S1) Press the power button 312 of the power supply unit 31 (S1).
1), the entire controller is reset and the controller is in the initial state. (S2) That is, the time display of the energization time display section 343 is reset to 0, and (S3) the mounting lamp 321 of the plug mounting section 32 is turned on. (S4) When the two fusion plugs 9 are respectively connected to the joint 1, (S5) the plug mounting lamp 321 goes out, and (S6) the connection lamp 331 of the connection section 33 turns on.

(S7) Next, the energizing button 3 of the energizing section 34
When the button 42 is pressed (S8), the energizing lamp 341 starts blinking. In this state, power is not yet supplied, and the operating state of the thermocouple 6 is checked. (S9) If the thermocouple 6 is not broken, (S10) A change in temperature as to whether the temperature of the thermocouple 6 accurately measures the temperature of the joint is examined. (S10, S8, S9) Here, the process waits until the thermocouple itself does not have the thermal effect of the previous fusion work, that is, until the temperature change converges. (S11) When there is no change in the temperature of the thermocouple, an initial temperature T0 before fusion of the pipe joint is detected. (S12) First energization stop temperature T based on initial temperature T0
1 is obtained and stored in the memory.

(S13) Subsequently, the second energization stop temperature Ts is obtained based on the initial temperature T0. The second power supply stop temperature T2 is set to, for example, 70% of the first power supply stop temperature T1. (S14) A predetermined voltage is applied from the controller to the fusion plug 9
Is output to the heating wire 2 via (S15) The energization lamp 341 changes from blinking to lighting. (S16) The buzzer sounds with a low tone to notify the energized state. (S17) Whether or not the thermocouple 6 is disconnected, (S18) whether or not the heating wire 2 is shorted, (S19) whether or not the output voltage is abnormally supplied to the heating wire 2, (S20) is supplied to the heating wire 2. It is determined whether there is an output current abnormality.

If there is no abnormality from S18 to S20, (S21) a predetermined elapsed time Ti, for example, if 10 seconds have elapsed after the start of energization, (S22) the elapsed time Ti for identifying the bore size of the pipe joint The temperature (the temperature rise rate of the pipe joint) is detected. As the temperature for identifying the dimensions, the temperature of the double concave hole, that is, the temperature Tp of the fused portion at the concave portion 14 and the temperature Tv of the concave portion 15 located at a position away from the fused portion is detected. (S23) The bore size of the pipe joint is identified based on the temperatures Tp and Tv (or the heating rate) of the concave holes 14 and 15. This identification is obtained from a predetermined temperature (or heating rate). (S24) An energization stop time S1 based on the identified pipe joint dimension and a (S25) final energization time S2 based on the identified pipe joint dimension are obtained and stored in the memory. (S26) When the detected temperature Tp of the concave hole 14 reaches the first energization completion temperature T1, (S27) energization to the heating wire 2 is stopped. (Line B in FIG. 7)
(S28) Then, the power supply circuit in the controller is shut off. (S29) The energizing lamp 341 that was turned on is turned off, (S30) the low tone of the buzzer stops, and (S31) 35 cooling lamps 35 indicating that cooling is being performed instead.
1 lights up.

(S32) When a predetermined cooling time corresponding to the joint has elapsed, (S33) the cooling time of the power-on time display section 343 indicates 0, and the cooling lamp 351 is turned off. (S34) Then, the lamp 361 outside the plug attached to the outside 36 indicating the removal of the plug is turned on. (S35) When the two fusion plugs 9 are removed from the joint 1, (S36) the plug removal lamp 361 turns off.

Here, if the first energization stop temperature T1 in S26 has not been reached, (S37) if the energization stop time S1 obtained in S24 has been reached, (S38) it is checked whether it is equal to or higher than the second energization stop temperature T2, If the temperature Tp of the concave hole 14 is equal to or higher than T2 (Tp> T2), S2
Then, the output is stopped. (In the case of line A in FIG. 7) If Tp <T2, (S39) The determination in S38 is performed until the final energizing time S2 is reached, and if Tp> T2, the output is stopped in S38 (line C in FIG. 7). ), If Tp <T2 even when the final energization time S2 has been reached, it is regarded as a fusion failure. (S42) The buzzer sounds at high temperature. (S43) The plug removal lamp 361 lights up. (S44) When the plug is removed, (S45) the plug removal lamp 361 goes off, and (S46) the high temperature of the buzzer stops. The fusing device of the present invention is controlled as described above.

[0024]

As described above, according to the current welding method for an electric fusion joint of the present invention, the diameter of a pipe joint can be accurately identified during the current fusion welding even for a large diameter pipe having a small difference in resistance value. . Further, while accurately grasping the state of the heat fusion, the power supply to the pipe joint is controlled from both the surface during the fusion based on the initial temperature of the pipe joint and the power supply time based on the diameter of the pipe joint.
For this reason, the pipe and the pipe joint are not excessively welded or insufficiently welded, and the entire welded portion can be accurately and uniformly welded and connected.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a state where a resin pipe according to one embodiment of the present invention is inserted into a pipe joint.

FIG. 2 is a plan view of FIG.

FIG. 3 is a partial cross-sectional view showing a state in which a fusion plug 9 of a controller is mounted on the pipe joint 1;

FIG. 4 is a front view showing a display panel of the controller.

FIG. 5 is a diagram showing a flow of a controller.

FIG. 6 shows an example of a fitting state of a pipe and a pipe joint, (a) and (b).
It is a figure which shows (c) and (d).

FIG. 7 is a diagram illustrating an example of a relationship between a temperature rising state of the pipe joint and control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric fusion joint 2 Heating wire 6 Thermocouple thermometer 8 Electrical connection connector 9 Fusion plug 11 Connection member 13 Opening 14, 15 Temperature measurement concave hole 16 Indicator hole 21, 22 Terminal

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B29C 65/34 F16L 47/02

Claims (3)

(57) [Claims] 1. A pipe joint made of a thermoplastic resin provided with a heating wire for heating on an inner peripheral surface thereof, and a pipe made of a thermoplastic resin inserted into an inner peripheral surface of the pipe joint, a predetermined length of the heating wire. In supplying the electric power and performing fusion splicing by electric current heating, the heating rate is obtained from the temperature of the pipe fitting detected while the heating wire is energized, and the dimension of the pipe fitting is identified from the heating rate. ,
An energization control method for an electro-fusion joint, wherein an energization stop time for stopping energization of the heating wire is controlled according to the dimension. 2. A pipe joint made of a thermoplastic resin provided with a heating wire for heating on an inner peripheral surface thereof, and a pipe made of a thermoplastic resin inserted into an inner peripheral surface of the pipe joint, a predetermined length of the heating wire. At the time of supplying the electric power and performing fusion welding by electric current heating, a temperature sensor is attached to the pipe joint, an initial temperature of the pipe joint is detected by the temperature sensor, and power is supplied to the heating wire from the initial temperature. Determine the energization stop temperature to stop, determine the temperature rise rate from the temperature of the pipe joint detected while energizing the heating wire, perform the dimension identification of the pipe joint from this temperature rise rate,
An energization control method for an electrofusion joint, comprising: determining an energization stop time for stopping energization of the heating wire according to the dimension; controlling energization of the heating wire from both the energization stop temperature and the energization stop time. . 3. A pipe joint made of a thermoplastic resin provided with a heating wire for heating on an inner peripheral surface thereof, and a pipe made of a thermoplastic resin inserted into the inner peripheral surface of the pipe joint, are fixed to the heating wire. At the time of supplying the electric power and performing fusion welding by electric current heating, a temperature sensor is attached to the pipe joint, an initial temperature of the pipe joint is detected by the temperature sensor, and power is supplied to the heating wire from the initial temperature. The first energization stop temperature (T1) at which the heating is stopped and the second energization stop temperature (T2) set at a certain value equal to or lower than the first energization stop temperature are obtained, and the temperature is increased from the temperature of the pipe joint detected while energizing the heating wire. Determine the temperature rate, identify the dimensions of the fittings from this rate,
An energization stop time (S1) for stopping energization of the heating wire is determined according to this dimension, and before reaching the determined energization stop time (S1), the temperature of the pipe joint energizing the heating wire is equal to the first energization time. Stop temperature (T
When reaching 1), the power supply to the heating wire is stopped. When the power supply stop time (S1) has been reached, and the temperature of the pipe joint during power supply has reached the second power supply stop temperature (T2), An energization control method for an electric fusion joint, wherein energization of a heating wire is stopped.