JP6830015B2 - Energization control device for electric fusion joints, energization control method, and manufacturing method of piping members - Google Patents

Description

The present application discloses an energization control device and an energization control method for an electric fusion joint used for pipe connection. Further, the present application discloses a method of manufacturing a piping member using this energization control device.

Electric fusion joints are widely used as joints for connecting resin pipes. In an electrofusion joint, a heating wire is embedded in the inner peripheral surface of the insertion portion (receptacle portion) of the pipe to be connected in the joint body (Patent Document 1 and the like). After inserting the pipe into the receiving portion of the joint body, the heating wire is heated by energization to melt the vicinity of the joint surface, whereby the joint body and the pipe can be joined. In this case, it is necessary to control the energization of the heating wire by using an energization control device to adjust the heat generation temperature of the heating wire (Patent Document 2 and the like).

As an example of the energization control method of the electric fusion joint, for example, a method of constant voltage control, a method of constant current control, and a method of controlling voltage and current to control constant power from the start to the end of energization are used. It is known (Patent Documents 3, 4, etc.). In these methods, the temperature of the heating wire cannot be precisely controlled, and there is a risk of resin deterioration due to overheating and bonding failure due to insufficient heating.

On the other hand, as another example of the energization control method of the electric fusion joint, for example, a method of keeping the heating wire temperature of the joint constant is known (Patent Documents 5, 6 and the like). In this method, by controlling the temperature of the heating wire, the temperature of the resin around the heating wire does not rise or fall too much, so deterioration of the resin due to overheating and joint failure due to insufficient heating are suppressed. it can.

Japanese Unexamined Patent Publication No. 2016-035327 Japanese Patent No. 5637228 Japanese Unexamined Patent Publication No. 9-323358 Japanese Unexamined Patent Publication No. 3-47737 JP-A-64-31624 Japanese Unexamined Patent Publication No. 2001-289388

As a method of keeping the heating wire temperature of the joint constant, the temperature dependence of the resistance value of the heating wire is used, the heating wire resistance value is controlled as an alternative value of the heating wire temperature, and the heating wire resistance value is set to a predetermined value. It is considered that a constant resistance control method that raises the target resistance value (corresponding to the target temperature) and holds the target resistance value for a certain period of time is effective. In the constant resistance control method, for example, the resistance calculated from the supply voltage value and the current value is sequentially monitored, and the supply power is adjusted to control the target resistance value to be held for a certain period of time.

Here, since the fusion area differs depending on the type (type, nominal diameter) of the electric fusion joint, and the electric power to be supplied also differs, the energization control is performed before starting the energization of the joint by using the energization control device. It is necessary to set the power supplied from the device to the fitting. As a method of setting the power to be supplied, there are a method of selecting the type of joint by a manual switch provided in the energization control device and a method of causing the energization control device to automatically recognize the type of joint. As a method of automatically recognizing the type of the joint, there are a method of recognizing based on the difference in the heating wire resistance value of the joint and a method of recognizing from external information (reading a barcode or the like installed in advance on the joint).

Of these, in the method of automatically recognizing the type of joint based on the difference in the heating wire resistance value of the joint, the heating wire resistance value of the joint is designed so that the heating wire resistance values do not overlap for each type of joint. There is a need. However, due to the design, the heating wire resistance values may overlap each other in different types of joints. When the heating wire resistance values of different types of joints overlap each other, it is impossible to automatically identify the energization control device, so it is necessary to manually select the type of joint. However, in this case, there is a risk of making a mistake in the manual selection.

Basically, a joint with a large nominal diameter (large joint diameter) requires a large amount of power because it has a large fusion area. On the other hand, a joint having a small nominal diameter (small joint diameter) requires a small amount of power supply because the fusion area is small. Therefore, as shown in FIG. 1, when the joint type is erroneously selected in the manual selection, the increase in the heating wire resistance value from the start of energization also differs due to the difference in the power supplied to the joint. It ends up. Specifically, when a joint with a large nominal diameter is selected and energization is started for a joint with a small nominal diameter, a larger amount of power than the required power supply is supplied, so that the power is supplied earlier than usual. The target resistance value is reached, causing problems such as excessive heat generation. On the other hand, when a joint with a small nominal diameter is selected and energization is started for a joint with a large nominal diameter, less power is supplied than the required power supply, so it is normal to reach the target resistance value. It takes longer than that, and problems such as insufficient heating and poor fusion splicing occur.

Also, in the case of constant resistance control, the target resistance value differs depending on the type of joint, so if the manual selection is incorrect, the target resistance value will also be set incorrectly, which is also a problem of overheating. And problems such as insufficient heating may occur.

In view of the above problems, in the present application, if the joint type is erroneously selected before energizing the electrically fused joint, the energization is stopped before the constant resistance control is reached, and the quality is poor due to the erroneous selection of the joint type. Disclosed is an energization control device and an energization control method for an electric fusion joint capable of preventing the occurrence of.

The present application provides one of the means for solving the above problems.
A device that controls energization of the heating wire when power is supplied to the heating wire of the electrofusion joint to fuse the electric fusion splicer and the pipe, and energization of the electrofusion joint is started. The resistance value of the heating wire of the joint is read before, and if the read resistance value is included in the resistance value range of a plurality of types of joints, one of the plurality of types of joints is manually selected. According to the joint type selection function and the type of joint selected in the joint type selection function, the resistance value of the heating wire is raised to the target resistance value by energization and then held at the target resistance value for a certain period of time. At the detection time point between the basic control function and the start of energization of the heating wire by the basic control function until the resistance value of the heating wire reaches the target resistance value, the resistance value of the heating wire is set in advance. Disclosed is an energization control device provided with a erroneous selection determination function of stopping the supply of electric power to the heating wire when the resistance value range deviates from a predetermined range.

It is preferable that the energization control device of the present disclosure has a correction function for correcting the resistance value range and / or the detection time point by the ambient temperature.

The present application provides one of the means for solving the above problems.
A device that controls the energization of the heating wire when power is supplied to the heating wire of the electric fusion joint to fuse the electric fusion joint and the pipe, and the energization of the electric fusion joint is started. The resistance value of the heating wire of the joint is read before, and if the read resistance value is included in the resistance value range of a plurality of types of joints, one of the plurality of types of joints is manually selected. Joint type selection function and
A basic control function that raises the resistance value of the heating wire to the target resistance value by energization and then holds it at the target resistance value for a certain period of time according to the type of joint selected in the joint type selection function. If the resistance value of the heating wire does not rise to the target resistance value even after a predetermined time point has elapsed after starting the energization of the heating wire by the basic control function, the power to the heating wire is supplied. Discloses an energization control device having a misselection determination function for stopping the supply of power.

It is preferable that the energization control device of the present disclosure has a correction function for correcting the specified time point by the environmental temperature.

The present application provides one of the means for solving the above problems.
This is a method of controlling the energization of the heating wire when the electric fusion joint and the pipe are fused by supplying electric power to the heating wire of the electric fusion joint, and the energization of the electric fusion joint is started. If the resistance value of the heating wire of the joint is read before and the read resistance value is included in the resistance value range of a plurality of types of joints, one of the plurality of types of joints is selected and selected. When the resistance value of the heating wire is raised to the target resistance value by energization according to the type of joint, the detection between the start of energization of the heating wire and the resistance value of the heating wire reaching the target resistance value. Disclosed is an energization control method for stopping the supply of electric power to the heating wire when the resistance value of the heating wire deviates from a predetermined resistance value range at a time point.

In the energization control method of the present disclosure, it is preferable to correct the resistance value range and / or the detection time point by the environmental temperature.

The present application provides one of the means for solving the above problems.
This is a method of controlling the energization of the heating wire when the electric fusion joint and the pipe are fused by supplying electric power to the heating wire of the electric fusion joint, and starts energization of the electric fusion joint. If the resistance value of the heating wire of the joint is read before and the read resistance value is included in the resistance value range of the plurality of types of joints, one of the plurality of types of joints is selected and selected. When the resistance value of the heating wire is raised to the target resistance value by energization according to the type of joint, if the resistance value of the heating wire does not rise to the target resistance value even after a predetermined time point has passed. Disclosed is an energization control method for stopping the supply of electric power to the heating wire.

In the energization control method of the present disclosure, it is preferable to correct the specified time point by the environmental temperature.

The present application also discloses a method for manufacturing a piping member, which comprises a step of fusing an electric fusion joint and a pipe by the energization control device of the present disclosure.

In the energization control device and the energization control method of the present disclosure, when the resistance value of the heating wire deviates from a predetermined resistance value range at a predetermined detection time point after the energization of the heating wire is started, or a predetermined specification If the resistance value of the heating wire does not rise as planned even after the time point is exceeded, the energization of the heating wire is stopped. That is, if the joint type is erroneously selected before energizing the electrically fused joint, the energization is appropriately stopped before the constant resistance control is reached, and the occurrence of quality defects due to the erroneous selection of the joint type is prevented. It is possible.

It is a figure for demonstrating the problem which occurs at the time of wrong selection of a joint type. It is a figure for demonstrating the joint type selection function. It is a figure for demonstrating the basic control function. It is a figure which shows an example of the time-dependent change of the current value, the voltage value and the resistance value of a heating wire by a basic control function. It is a figure for demonstrating the erroneous selection determination function which concerns on 1st Embodiment. It is a figure for demonstrating the difference in the heating wire resistance value (difference in resistance value at the start of energization, difference in the rising speed after the start of energization) due to the difference in environmental temperature. It is a figure for demonstrating the resistance value range correction function, and the detection time point correction function. It is a figure for demonstrating the erroneous selection determination function which concerns on 2nd Embodiment. It is a figure for demonstrating the target resistance value correction function (the 1). It is a figure for demonstrating the output correction function. It is a figure for demonstrating the energization stop function. It is a figure for demonstrating the target resistance value correction function (the 2). It is a figure for demonstrating the resistance value monitoring function. It is a figure for demonstrating the problem of an overshoot. It is a figure for demonstrating the holding control start function.

1. 1. Energization control device (first embodiment)
The energization control device according to the first embodiment is a device that controls energization of the heating wire when power is supplied to the heating wire of the electric fusion joint to fuse the electric fusion joint and the pipe. , Read the resistance value of the heating wire of the joint before starting to energize the electrically fused joint, and if the read resistance value is within the range of the resistance value of multiple types of joints, one of the multiple types of joints Depending on the joint type selection function that allows you to manually select one and the joint type selected in the joint type selection function, the resistance value of the heating wire is raised to the target resistance value by energization and then set to the target resistance value. The resistance value of the heating wire is set in advance at the detection time point between the start of energization of the heating wire by the basic control function and the time when the resistance value of the heating wire reaches the target resistance value. It is equipped with a erroneous selection judgment function that stops the supply of power to the heating wire when it deviates from the specified resistance value range.

1.1. Joint type selection function FIG. 2 shows the flow of selection by the joint type selection function. As shown in FIG. 2, the energization control device of the present disclosure is electrically connected to an electric fusion joint so that the heating wire can be energized, and the joint is connected before the start of energization of the electric fusion joint. When the resistance value of the heating wire is read (S1) and the read resistance value is included in the range of the resistance values of multiple types of joints (that is, when the read resistance value overlaps with the resistance values of multiple types of joints) ), One of the plurality of types of joints is manually selected (S2), and has a joint type selection function. As a result, the energization data is appropriately read according to the type of the joint, the supplied power and the like are optimally set, and deterioration of the resin due to overheating and poor fusion due to insufficient heating can be prevented.

As shown in FIG. 2, in the energization control device of the present disclosure, the joint type selection function reads the resistance value of the heating wire of the joint before starting energization of the electrically fused joint (S1), and the read resistance. When the value is included only in the range of the resistance value of one type of joint (that is, when the read resistance value does not overlap with the resistance value of multiple types of joints), the one type of joint is automatically selected (S2). ') It is preferable to have further functions. As a result, the energization data is appropriately read according to the type of the joint, the supplied power and the like are optimally set, and deterioration of the resin due to overheating and poor fusion due to insufficient heating can be prevented.

1.2. Basic control function The basic control function is based on the target resistance value after raising the resistance value of the heating wire of the electrically fused joint to the target resistance value by energization according to the type of joint selected in the joint type selection function. It is a function to hold for a certain period of time. FIG. 3 shows the relationship between the energization time by the basic control function and the resistance value of the heating wire.

As shown in FIG. 3, the resistance value of the heating wire of the electric fusion joint is increased to the target resistance value by energization by the energization control device. Here, since the resistance value of the heating wire and the temperature of the heating wire are in a substantially proportional relationship, the temperature of the heating wire also rises as the resistance value of the heating wire rises, and the temperature of the heating wire corresponds to the target resistance value. Reach a predetermined temperature. After that, the heating wire is held at the target resistance value for a certain period of time. That is, heat is generated for a certain period of time at a predetermined temperature corresponding to the target resistance value. At this time, the resin around the heating wire is melted, and the electric fusion joint and the connecting pipe (resin pipe) are fused.

In order to control the resistance value described above, in the basic control function, feedback control is performed on the resistance value of the heating wire, and the electric power supplied to the heating wire is adjusted. Here, in the energization control device of the present disclosure, it is preferable that the energization is controlled by the basic control function in the manner shown in FIG. That is, while increasing the resistance value (temperature) of the heating wire, first perform constant current control (control to change the voltage with the current value constant) (STEP 1), and then perform constant voltage control (with the voltage constant). It is preferable to perform control to change the current) (STEP 2) to bring the resistance value of the heating wire to reach the target resistance value. The current value in constant current control and the voltage value in constant voltage control may be set for each type of joint. By performing constant voltage control after performing constant current control in this way, the supply power increase characteristic of the constant current control due to the increase in the heating wire resistance value and the supply due to the increase in the heating wire resistance value of the constant voltage control Due to the power suppression characteristics, it is possible to form a slow and smooth increase in the heating wire resistance value in the vicinity of the target resistance value quickly from the start of energization. On the other hand, after the resistance value of the heating wire reaches the target resistance value, the voltage and current are gradually reduced (reduced the power supply) with the passage of time in order to maintain the target resistance value for a certain period of time. Then, constant resistance control is performed (STEP 3). The target resistance value in the constant resistance control may be set for each type of joint. The means for causing the energization control device to recognize the resistance value of the heating wire and the means for realizing feedback control are not particularly limited and are obvious to those skilled in the art, and thus the description thereof will be omitted here.

The speed and time for increasing the resistance value of the heating wire, the target resistance value of the heating wire, and the time for holding at the target resistance value are not particularly limited, and the type of the electric fusion joint is not particularly limited. It may be decided as appropriate according to the above.

As shown in FIGS. 3 and 4, after holding the target resistance value for a certain period of time, the energization from the energization control device to the heating wire is terminated. As a result, the resistance value (temperature) of the heating wire gradually decreases. After the energization is completed, the fusion work is completed after a certain cooling time. The cooling time is not particularly limited.

1.3. Incorrect selection judgment function In the energization control device of the present disclosure, when the type of the electric fusion joint is manually selected by the joint type selection function before the start of energization of the electric fusion joint, the operator mistakenly selects the type of the joint. You may make a choice. In such a case, the energization control device of the present disclosure has a function of determining that the selection of the joint type by the operator was erroneous and stopping the energization.

Basically, a joint with a large nominal diameter (large joint diameter) requires a large amount of power because it has a large fusion area. On the other hand, a joint having a small nominal diameter (small joint diameter) requires a small amount of power supply because the fusion area is small. Therefore, as shown in FIG. 1, when the joint type is erroneously selected in the manual selection, the increase in the heating wire resistance value from the start of energization also differs due to the difference in the power supplied to the joint. It ends up. Specifically, when a joint with a large nominal diameter is selected and energization is started for a joint with a small nominal diameter, a larger amount of power than the required power supply is supplied, so that the power is supplied earlier than usual. Reach the target resistance value. On the other hand, when a joint with a small nominal diameter is selected and energization is started for a joint with a large nominal diameter, less power is supplied than the required power supply, so it is normal to reach the target resistance value. It takes longer than. In the energization control device of the present disclosure, this is utilized to determine the erroneous selection of the joint type of the operator and stop the energization.

That is, as shown in FIGS. 5A and 5B, the energization control device of the present disclosure is from the start of energization of the heating wire by the basic control function until the resistance value of the heating wire reaches the target resistance value. When the resistance value of the heating wire deviates from the predetermined resistance value range at the detection time point of, the erroneous selection determination function for stopping the supply of electric power to the heating wire is provided.

Specifically, when manually selecting the type of joint in the above-mentioned joint type selection function, the operator has a larger nominal diameter (larger joint diameter) than a joint with a smaller nominal diameter (smaller joint diameter). When a joint is selected, as shown in FIG. 5 (A), the power supply becomes excessive after the actual energization starts, and the resistance value rises rapidly. Therefore, the resistance value of the heating wire at the detection time point is predetermined. It deviates from the upper limit of the resistance value range. That is, when the resistance value of the heating wire at the detection time point exceeds the upper limit of the predetermined resistance value range, the energization control device considers that the operator has incorrectly selected the type of joint and stops energization. As a result, the energization can be stopped before problems such as overheating occur, and the occurrence of quality defects due to erroneous selection of the joint type can be prevented.

Similarly, when manually selecting the type of joint in the above-mentioned joint type selection function, the operator selects a joint having a small nominal diameter (small joint diameter) with respect to a joint having a large nominal diameter (large joint diameter). When selected, as shown in FIG. 5 (B), the power supply becomes insufficient after the actual energization starts, and the increase in the resistance value becomes slow. Therefore, the resistance value of the heating wire at the detection time point is a predetermined resistance value. It deviates from the lower limit of the range. That is, when the resistance value of the heating wire at the detection time point falls below the lower limit of the predetermined resistance value range, the energization control device considers that the operator has incorrectly selected the type of joint and stops energization. As a result, the energization can be stopped before problems such as insufficient heating and poor joining are reached, and the occurrence of quality defects due to erroneous selection of the joint type can be prevented.

The detection time point may be set according to the amount of power to be supplied to the joint, the rising behavior of the heating wire resistance value for each type of joint, and the rising behavior of the heating wire resistance value when the type of joint is selected incorrectly. .. However, after starting the constant resistance control, the power supply is adjusted according to the rise and fall of the resistance value in order to keep the resistance value of the heating wire at the target resistance value, so it is not possible to set the detection time point. Can not. Therefore, in the energization control device of the present disclosure, it is preferable to set the detection time point at any time between the start of energization and the constant resistance control. If the detection time point is set immediately after the start of energization, it is difficult to determine the difference in the rising behavior of the heating wire resistance value for each type of joint. Therefore, the detection time point is set when a certain amount of time has passed from the start of energization. It is good to set. For example, it is preferable to set the detection time point at half the time from the start of energization to the constant resistance control. Specifically, when the time from the start of energization to the constant resistance control is 10 seconds, the detection time point may be set to a time point 5 seconds after the start of energization.

The resistance value range can also be set according to the amount of power to be supplied to the joint, the rising behavior of the heating wire resistance value for each type of joint, and the rising behavior of the heating wire resistance value when the type of joint is selected incorrectly. Good. Needless to say, the resistance value range is smaller than the target resistance value.

As described above, in the energization control device of the present disclosure, the detection time point is set while the heating wire resistance value is raised to a predetermined target resistance value from the start of energization, and the resistance value range is defined at the detection time point. .. When manually selecting the joint type in the above joint type selection function, if the operator correctly selects the joint type, the resistance value of the heating wire is determined at the detection time point after the actual energization is started. It is within the resistance value range of. That is, when the resistance value of the heating wire at the detection time point is within the predetermined resistance value range, it may be determined that it is normal and energization may be continued to perform constant resistance control at the target resistance value.

1.4. Resistance value range correction function, detection time point correction function As shown in FIG. 6, the heating wire resistance value of the joint before energization differs depending on the environmental temperature. That is, when the environmental temperature is low, the resistance value of the heating wire of the joint is small, and when the environmental temperature is high, the resistance value of the heating wire of the joint is large. Therefore, it is preferable that the energization control device of the present disclosure has a correction function for correcting the above-mentioned resistance value range and / or detection time point by the environmental temperature.

For example, as shown in FIG. 7A, when the environmental temperature is high, the resistance value range at the detection time point is shifted to the high resistance side, and when the environmental temperature is low, the resistance at the detection time point is shifted. It is advisable to shift the value range to the low resistance side. Alternatively, as shown in FIG. 7B, when the resistance value range is constant and the environmental temperature is high, the time from the start of energization to the detection time point is shortened, and when the environmental temperature is low, It is advisable to lengthen the time from the start of energization to the detection time point. As a result, it is possible to appropriately determine the erroneous selection of the joint type according to the environmental temperature during work.

The method of correcting the resistance value range and the detection time point is not particularly limited. For example, if the environmental temperature and T1, a standard temperature and T0, the lower limit of the resistance range of the detection time point _{t 1} and _{R T1_min,} the upper limit of the resistance range of the detection time point _{t 1} and the _{R T1_max,} the lower limit of the resistance range corrected by the ambient temperature _{R T1_min_T1} and the upper limit value _{R T1_max_T1,} using the lower limit value _{R T1_min_T0} and the upper limit value _{R T1_max_T0} the resistance range of standard temperature, for example, it is determined based on the following equation Can be done.

R _{t1_min_T1} = α × (T1-T0) + R _{t1_min_T0} (T1 ≦ T0) ... (1)
R _{t1_min_T1} = β × (T1-T0) + R _{t1_min_T0} (T1> T0) ... (2)
R _{t1_max_T1} = α × (T1-T0) + R _{t1_max_T0} (T1 ≦ T0) ... (3)
R _{t1_max_T1} = β × (T1-T0) + R _{t1_max_T0} (T1> T0) ... (4)

Here, α and β are correction coefficients. α and β may have the same value. α and β can be set for each type of joint.

2. 2. Energization control device (second embodiment)
The energization control device according to the second embodiment is a device that controls energization to the heating wire when electric power is supplied to the heating wire of the electric fusion joint to fuse the electric fusion joint and the pipe. , Read the resistance value of the heating wire of the joint before starting to energize the electrically fused joint, and if the read resistance value is within the range of the resistance value of multiple types of joints, one of the multiple types of joints Depending on the joint type selection function that allows you to manually select one and the joint type selected in the joint type selection function, the resistance value of the heating wire is raised to the target resistance value by energization and then set to the target resistance value. When the resistance value of the heating wire does not rise to the target resistance value even after a predetermined time point has passed after starting the energization of the heating wire by the basic control function and the basic control function that hold the heating wire for a certain period of time. , It is equipped with a misselection judgment function that stops the supply of power to the heating wire.

2.1. Joint type selection function and basic control function The joint type selection function and basic control function are the same as those of the energization control device according to the first embodiment. The description is omitted here.

2.2. Misselection determination function As shown in FIG. 8, the energization control device of the present disclosure has a resistance value of the heating wire even after a predetermined time point has elapsed after starting energization of the heating wire by the basic control function. If does not rise to the target resistance value, it has a misselection judgment function that stops the supply of power to the heating wire.

The specified time point may be later than the time point for switching to constant resistance control. That is, when the resistance value of the heating wire does not reach the target resistance value even though the time point for switching to the constant resistance control is exceeded, the energization of the heating wire is stopped. The specified time point may be set according to the amount of power to be supplied to the joint, the rising behavior of the heating wire resistance value for each type of joint, and the rising behavior of the heating wire resistance value when the type of joint is selected incorrectly. ..

The energization control device of the present disclosure may have both the erroneous selection determination function according to the first embodiment and the erroneous selection determination function according to the second embodiment. As a result, it is possible to more effectively prevent the occurrence of quality defects due to incorrect selection of the joint type.

For example, as shown in FIG. 8, even if the heating wire resistance value at the detection time point is within the predetermined resistance value range, the heating wire resistance value remains at the predetermined target resistance value even after the predetermined time point has passed. May not rise to. In this case, the wrong selection judgment function considers that the joint type selection in the joint type selection function is incorrect and stops the energization of the heating wire, so that the energization is stopped before problems such as insufficient heating and poor joining occur. It is possible to prevent the occurrence of quality defects due to incorrect selection of the joint type.

2.3. Specified time point correction function The energization control device according to the second embodiment preferably has a correction function for correcting the above-mentioned specified time point by the environmental temperature. The actions and effects of such a correction function are as described above, and description thereof will be omitted here. The method of correcting the specified time point according to the environmental temperature is not particularly limited.

3. 3. Other Functions The energization control device of the present disclosure can be provided with the following functions in addition to the above-mentioned various functions in both the first embodiment and the second embodiment.

3.1. Target resistance value correction function (1)
According to the findings of the present inventors, when the energization control of the heating wire is performed by the energization control device having the above-mentioned basic control function, the resistance value of the heating wire is held at the target resistance value for a certain period of time. When a short circuit occurs in the heating wire (such as when adjacent heating wires come into contact with each other in the wound heating wire), the resistance value of the heating wire is set to the target resistance value even though the resistance of the heating wire drops immediately after the short circuit. Therefore, the power supplied to the heating wire becomes excessive, and the heating by the heating wire may become excessive. In order to prevent such a situation, as shown in FIG. 9, the energization control device of the present disclosure is used when the heating wire is short-circuited and the resistance value is lowered while the target resistance value is held for a certain period of time. It is preferable to have a target resistance value correction function that changes the target resistance value to a resistance value lowered by a short circuit.

In the target resistance value correction function, for example, while the resistance value of the heating wire is monitored and feedback control is sequentially performed to hold the heating wire at the target resistance value, a predetermined time before the measurement time (for example, for example). , 0.01 seconds ago to 1.0 seconds ago) The resistance value R0 of the heating wire is compared with the current resistance value R1 of the heating wire at the time of measurement, and the resistance value changes above the threshold between R0 and R1. When (decrease) occurs, it is judged that a short circuit has occurred in the heating wire. When it is determined that a short circuit has occurred, the target resistance value is changed to the resistance value R1 after the short circuit occurs, and the supply voltage and current to the heating wire are changed so as to satisfy the resistance value R1. The amount of change in the supply voltage and current may be determined based on the difference between the initial target resistance value and the new target resistance value R1. For example, it is preferable to change the voltage supplied to the heating wire after a short circuit by equipping the energization control device with an output correction function described later.

On the other hand, after the resistance value decreases due to the short circuit of the heating wire (after the resistance value becomes R1), the short circuit is released (contact between the heating wires is eliminated) and the resistance value of the heating wire increases (resistance value). Is R2 larger than R1). In such a case, if the target resistance value is left as the resistance value R1, the supplied power is insufficient, which causes poor fusion due to insufficient heating. Therefore, in the energization control device of the present disclosure, the above-mentioned target resistance value correction function changes the target resistance value to the increased resistance value R2 when the short circuit of the heating wire is released and the resistance value of the heating wire increases. It is preferable to have a function to change. In this case, the supply voltage and current to the heating wire are changed so as to satisfy the resistance value R2. The amount of change in the supply voltage and current may be determined based on the difference between the initial target resistance value R1 and the new target resistance value R2. For example, it is preferable to change the voltage supplied to the heating wire after a short circuit by equipping the energization control device with an output correction function described later.

3.2. Output correction function As shown in FIG. 10, when the resistance value and supply voltage before the short circuit of the heating wire are R0 and V0, and the resistance value and supply voltage after the short circuit of the heating wire are R1 and V1, the supply before the short circuit is performed. The power W0 and the power supply W1 after a short circuit are represented by the following equations (5) and (6) from Joule's law and Ohm's law.
W0 = V0 ² / R0 ... (5)
W1 = V1 ² / R1 ... (6)

Here, assuming that the power supply before and after the short circuit is equivalent (W0 = W1), the following relationship holds from the equations (5) and (6).
V0 ² / R0 = V1 ² / R1 ... (7)

From the above, the energization control device of the present disclosure is V1 when the resistance value and supply voltage before the short circuit of the heating wire are R0 and V0, and the resistance value and supply voltage after the short circuit of the heating wire are R1 and V1. It is preferable to have an output correction function that changes the supply voltage after a short circuit so as to satisfy the relationship of = V0 × (R1 / R0) ^1/2 . As a result, the electric power supplied to the heating wire becomes the same before and after the short circuit, and the above-mentioned excessive heating can be prevented more easily. For example, the supply voltage may be changed from V0 to V1 immediately after it is determined that a short circuit has occurred (for example, after 0.01 seconds to 1.0 seconds). Since it is obvious that R1 <R0, it is obvious that V1 <V0.

On the other hand, after the heating wire is short-circuited, if the short-circuit is released and the resistance value of the heating wire rises, the output correction function changes the supply voltage as follows. That is, the energization control device of the present disclosure has V2 = V1 when the resistance value and supply voltage when the heating wire is short-circuited are R1 and V1, and the resistance value and supply voltage after the short-circuit release of the heating wire is R2 and V2. It is preferable to have an output correction function that changes the supply voltage after the short circuit is released so as to satisfy the relationship of × (R2 / R1) ^1/2 . For example, the supply voltage is changed from V1 to V2 immediately after it is determined that the short circuit has been released (for example, after 0.01 seconds to 1.0 seconds). Since it is obvious that R1 <R2, it is obvious that V1 <V2.

3.3. Energization stop function When the heating wire is held at the target resistance value for a certain period of time, it is assumed that the heating wire may be short-circuited multiple times. In this case, the target resistance value is sequentially changed by the above-mentioned target resistance value correction function. However, if the number of short circuits of the heating wire is too large, the resistance value is excessively lowered, the arrangement of the heating wire is greatly disturbed, the heat generation of the heating wire becomes non-uniform, and it causes poor fusion. Therefore, it is preferable that the energization control device of the present disclosure is provided with the energization stop function shown below to stop the energization when the resistance value of the heating wire is excessively lowered and notify the operator of the abnormality.

That is, as shown in FIG. 11, it is preferable that the energization control device of the present disclosure has an energization stop function of stopping energization when the resistance value after a short circuit of the heating wire falls below the threshold value. In this case, the threshold value of the resistance value, which is the reference for stopping the energization, may be appropriately determined according to the type of the electric fusion joint and the like. Alternatively, the energization may be stopped when the number of times that the heating wire is determined to have been short-circuited by the target resistance value correction function exceeds the threshold value.

As described above, the energization control device of the present disclosure is provided with a basic control function and a target resistance value correction function, so that the electric power supplied to the heating wire is controlled in response to a short circuit, and an excessive electric power is supplied to the heating wire. Will not be done. Therefore, the heating by the heating wire does not become excessive, and stable joint fusion splicing quality can be obtained.

3.4. Target resistance value correction function (2)
If the heating wire resistance value as an alternative value to the heating wire temperature is set to the same target resistance value when the environmental temperature during work is different, the reaching heating wire temperature will be the same, but due to the influence of the environmental temperature, in a low temperature environment Heat dissipation to the outside of the environment is promoted and the temperature of the junction interface is difficult to rise. In a high temperature environment, heat dissipation to the outside of the environment is suppressed and the temperature of the junction interface is likely to rise. May change. Considering this, it is preferable that the energization control device of the present disclosure has a function of correcting the target resistance value according to the environmental temperature, as shown in FIG. That is, when the environmental temperature is lower than the reference temperature, the target resistance value is corrected to be higher than the reference resistance value, and when the environmental temperature is higher than the reference temperature, the target resistance value is made lower than the reference resistance value. It is preferable to correct to.

Regarding the correction of the target resistance value, for example, the target resistance value at the reference temperature T0 (for example, 25 ° C.) is set to R _max , and the target resistance value corrected according to the environmental temperature T1 is set to R _max ', based on the following equation. It is feasible.
R _max '= [1+ (T0-T1) x γ] x R _max (when T1 ≤ T0) ... (8)
R _max '= [1+ (T0-T1) x δ] x R _max (when T1> T0) ... (9)

In the above equations (8) and (9), γ and δ are correction coefficients, respectively. γ and δ may have the same value. Further, γ and δ can be set for each type of joint.

The correction of the target resistance value may be performed only when the difference between the environmental temperature and the reference temperature becomes equal to or larger than the threshold value.

3.5. Supply power correction function If the power supplied to the heating wire during the period from the start of energization to the predetermined target resistance value does not change before and after the correction of the target resistance value, there are the following concerns. That is, when the target resistance value is corrected to a low value, if the supply power corresponding to the target resistance value before correction is supplied as it is, the supply power becomes excessive and the target resistance value is overshooted (see FIG. 14). There is a risk that it will end up. Also, when the target resistance value is corrected to a high value, if the supply power corresponding to the target resistance value before correction is supplied as it is, the supply power will be insufficient and it will take a long time to reach the target resistance value. .. Therefore, the energization control device of the present disclosure corrects the amount of electric power supplied to the heating wire while raising the target resistance value by energization according to the target resistance value corrected by the above-mentioned target resistance value correction function. It is preferable to have a supply power correction function. As a result, as shown in FIG. 12, the resistance value of the heating wire can be smoothly reached to the corrected target resistance value after the start of energization.

The power supplied to the heating wire when increasing the resistance value of the heating wire is corrected by a function using the ambient temperature so as to be linked with the corrected target resistance value, or a function using the corrected target resistance value. Can be corrected by. For example, when the power supplied to the heating wire (corrected power supply) while raising the resistance value of the heating wire to a predetermined target resistance value is W, and the corrected target resistance value is R _max '.
W = A × R _max '+ B ・ ・ ・ (10)
The corrected power supply W can be set. In the equation (10), A and B are correction coefficients.

3.6. Resistance value monitoring function As described above, when the resistance value of the heating wire is held at the target resistance value by feedback control and constant resistance control is performed, the resistance value of the heating wire does not deviate significantly from the target resistance value. You need to control the value. That is, as shown in FIG. 13, in the energization control device of the present disclosure, when the resistance value of the heating wire is raised to the target resistance value by energization and then held at the target resistance value for a certain period of time, the resistance value of the heating wire is maintained. It is preferable to have a resistance value monitoring function that monitors the power supply to the heating wire so that the resistance value of the heating wire is between a preset upper limit and a lower limit of the threshold value. In this case, it is preferable to correct the upper limit of the resistance value and the lower limit of the threshold value according to the environmental temperature.

By combining the erroneous selection determination function according to the first embodiment and / or the erroneous selection determination function according to the second embodiment of the present disclosure and this resistance value monitoring function, the heating wire resistance value at the detection time point is predetermined. Even if it is within the resistance value range, if an abnormal excess or deficiency occurs in the resistance value increase after passing the detection time point, it can be detected at the upper and lower limits of the resistance value threshold, so that the occurrence of quality defects is more effective. It can be stopped.

3.7. Holding control start function As shown in FIG. 14, in the above-mentioned energization control device, when the resistance value of the heating wire reaches the target resistance value, even if the supply power is switched so as to hold the resistance value, the heating wire It is not possible to immediately stop the increase in the resistance value of the heating wire, the resistance value of the heating wire exceeds the target resistance value and overshoots, and the resistance value fluctuates due to the reaction returning toward the target resistance value again. Will end up. From this point of view, the energization control device of the present disclosure determines the resistance value of the heating wire when the resistance value of the heating wire reaches a predetermined resistance value lower than the target resistance value before reaching the target resistance value. It is preferable to have a holding control start function for starting the holding control. Specifically, as shown in FIG. 15, when the resistance value of the heating wire becomes any value between 90% and 98% or less of the target resistance value, the holding control of the resistance value of the heating wire is performed. It is preferable to start.

According to the findings of the present inventors, the overshoot rate and the resistance value fluctuation become large regardless of whether the holding control is started too early or too late. As shown in FIG. 15, the overshoot rate is determined by setting the time point at which the holding control is started to be any value between 90% and 98% or less of the target resistance value of the heating wire. For example, it can be reduced to 2% or less, and the fluctuation of the resistance value can also be reduced to, for example, 2% or less. In the energization control device of the present disclosure, more preferably, when the resistance value of the heating wire becomes any value between 92.5% and 97.5% or less of the target resistance value, the holding control is performed. Start. As a result, overshoot and fluctuation of resistance value can be further suppressed.

The holding control of the resistance value of the heating wire can be carried out by gradually reducing the voltage and current (reducing the supplied power) with the passage of time, for example, as in STEP 3 described above. When the holding control is performed by the energization control device of the present disclosure, the power supply may be gradually reduced while performing feedback control on the resistance value of the heating wire so that the resistance value is held at a predetermined target resistance value. .. As described above, the specific form of the means for causing the energization control device to recognize the resistance value of the heating wire and the means for realizing the feedback control is not particularly limited.

4. Other Obvious Configuration The energization control device of the present disclosure can energize the heating wire of the electric fusion joint in any of the first embodiment and the second embodiment, and has various functions described above. It may be configured as follows. Those skilled in the art can easily implement the energization control device of the present disclosure by referring to the present application. For example, by combining a power supply, various measuring means (voltage measuring means, current measuring means, etc.), various switching means, a control circuit, etc., and forming a program so as to exert the above-mentioned functions, the energization of the present disclosure is made. The control device can be manufactured.

The energization control device of the present disclosure controls the resistance value of the heating wire as described above, and is premised on measuring the resistance value of the heating wire. In this case, for example, the resistance value can be indirectly measured by measuring the supply voltage and the current. The measurement range of the resistance value of the heating wire by the energization control device is appropriately determined according to the type of the heating wire. For example, it is preferably 0.3Ω or more and 5.0Ω or less. The measurement accuracy of the resistance value is not particularly limited, but when the measured resistance value is low (for example, 0.3Ω or more and 1.5Ω or less), it is preferably within ± 30mΩ, and the measured resistance value is When it is high (for example, more than 1.5Ω and 5Ω or less), it is preferably within ± 2.0%.

As described above, the resistance value of the heating wire changes depending on the environmental temperature. Therefore, when measuring the resistance value of the heating wire in the energization control device of the present disclosure, it is preferable to also measure the environmental temperature and reconvert the measured resistance value as the resistance value at the standard temperature (for example, 25 ° C.). .. The conversion method is not particularly limited. In this case, if the converted resistance value is not included in any of the specified resistance value ranges according to the type of joint, the resistance value may not be measured correctly, so an error buzzer or the like may be used. It is preferable to configure it so as to notify the operator to that effect.

As described above, the energization control device of the present disclosure preferably has a function of measuring the environmental temperature during use. In this case, the measurement accuracy of the environmental temperature is preferably ± 4 ° C. or less. The temperature measurement range is not particularly limited, but it is preferable to be able to measure as wide a range as possible in consideration of the storage temperature and the like. For example, it is preferably −20 ° C. or higher and 60 ° C. or lower. The environmental temperature during use can be measured by a temperature sensor.

5. Electric fusion joint The type of electric fusion joint whose energization is controlled by the energization control device of the present disclosure is not particularly limited. Any conventionally known electric fusion joint can be applied. Hereinafter, an example of the electric fusion joint will be described.

An electric fusion joint usually includes a joint body having a receiving portion and a heating element that covers the inner peripheral surface of the receiving portion, and the heating element generates heat by energizing through an energizing terminal and the energizing terminal. It is equipped with a heating wire. The "receptacle portion" means a portion where a pipe can be inserted and the pipe and the electric fusion joint can be joined. The "joint body" may be any as long as it has a receiving portion and can connect a pipe as a joint, and the shape is not particularly limited. The "inner peripheral surface of the receiving portion" means the inner wall of the receiving portion of the joint body. The "heating element covering the inner peripheral surface of the receiving portion" means that the heating element is provided along the shape of the inner peripheral surface of the receiving portion. The heating element is preferably provided so as to cover the entire inner peripheral surface of the receiving portion.

5.1. Shape and size of joint body (nominal diameter)
The shape of the joint body may be such that a pipe can be connected as a joint. It is possible to adopt the same shape as the joint body of the conventional electric fusion joint. For example, a cheese type, a socket type, an elbow type, a reducer type, a cap type, or any other known shape as a joint can be adopted. Further, the nominal diameter (diameter) of the joint is not particularly limited. For example, the diameter can be 5 mm or more and 250 mm or less.

5.2. Material of the joint body The material of the joint body may be any material that can connect pipes and can exhibit the performance as an electric fusion joint. It is possible to use the same material as the joint body of the conventional electric fusion joint. In particular, in consideration of moldability, mechanical properties, durability and the like, those made of crosslinked thermoplastic resin are preferable, and those made of crosslinked polyethylene are particularly preferable.

5.3. Heating wire A heating wire is a metal wire that generates heat when energized. The relationship between the resistance value and the temperature of the heating wire is approximately proportional. In particular, when a Ni wire, a Cu wire, an Fe wire or the like is used as the heating wire, the resistance value changes sensitively with respect to the temperature change, so that the heating wire temperature can be easily controlled by controlling the resistance value. The shape (thickness, etc.) of the heating wire is not particularly limited, and may be appropriately determined according to the shape and performance of the electric fusion joint. In the present application, the heating wire also includes a "pattern made of a thin metal film". For example, a metal foil patterned by punching or etching is also considered to correspond to the heating wire referred to in the present application.

6. Energization control method In the energization control method (first embodiment) of the present disclosure, when power is supplied to the heating wire of the electric fusion joint to fuse the electric fusion joint and the pipe, the heating wire is energized. In the control method, if the resistance value of the heating wire of the joint is read before the start of energization of the electrically fused joint and the read resistance value is included in the resistance value range of multiple types of joints, multiple types When one of the above joints is selected and the resistance value of the heating wire is raised to the target resistance value by energization according to the selected joint type, the resistance value of the heating wire is the target from the start of energization of the heating wire. When the resistance value of the heating wire deviates from a predetermined resistance value range at the detection time point until the resistance value is reached, the supply of electric power to the heating wire is stopped.
Further, the energization control method (second embodiment) of the present disclosure controls energization of the heating wire when electric power is supplied to the heating wire of the electric fusion joint to fuse the electric fusion joint and the pipe. If the resistance value of the heating wire of the joint is read before the start of energization of the electrically fused joint and the read resistance value is included in the resistance value range of multiple types of joints, multiple types of When one of the joints is selected and the resistance value of the heating wire is raised to the target resistance value by energization according to the type of the selected joint, the resistance of the heating wire even after a predetermined time point has passed. When the value does not rise to the target resistance value, the supply of electric power to the heating wire is stopped.
In such an energization control method, it is preferable to correct the above resistance value range, detection time point, and / or specified time point by the environmental temperature.

The operation and effect of such an energization control method are as described in the above energization control device, and the description thereof will be omitted here.

It can be said that the energization control method of the present disclosure controls energization of the electric fusion joint to the heating wire by an operation corresponding to various functions of the energization control device described above. That is, in the energization control method of the present disclosure, 1. ~ 3. Any of the operations corresponding to the various functions described in the above can be incorporated.

7. Manufacturing method of piping member A pipe is inserted into the receiving portion of the joint body of an electrically fused joint, and the heat transfer wire is generated by the energization control device of the present disclosure to generate heat and melt the vicinity of the joint surface. Can be connected. The piping member thus obtained can be applied to a water supply / hot water supply facility and a system by being connected to, for example, a water heater or the like. Water supply and hot water supply facilities and systems are not described here because they are obvious to those skilled in the art.

Hereinafter, the effects of the energization control device and method of the electric fusion joint of the present disclosure will be further described in detail based on Examples and Comparative Examples.

First, to an electrically fused joint (nominal diameter 13 mm or 20 mm) using an energization control device that has the above-mentioned "joint type selection function" and "basic control function" but does not have the "erroneous selection judgment function". Was energized. In the "joint type selection function", the difference in the amount of power supplied was confirmed between the case where the type (nominal diameter) of the electrically fused joint was selected correctly and the case where it was selected incorrectly. The results are shown in Table 1 below.

As shown in Table 1, it can be seen that when the type of joint is erroneously selected, an excessive supply of electric power or a shortage of electric power supply occurs during the fusion work.

Next, the electric fusion joint (nominal diameter 13 mm or 20 mm) is energized by using the energization control device having the above-mentioned "joint type selection function", "basic control function" and "erroneous selection determination function". It was. The experimental conditions and results are shown in Tables 2 and 3 below.

As is clear from the results shown in Tables 2 and 3, according to the energization control device provided with the above-mentioned "misselection determination function", the detection time point was set after the energization of the heating wire of the joint was started. The resistance value range was compared with the actual resistance value of the heating wire, and if the resistance value of the heating wire deviated from the resistance value range, it was judged as abnormal (x) and the energization could be stopped. Here, as is clear from the results shown in Tables 2 and 3, according to the energization control device provided with the above-mentioned "erroneous selection determination function", it is determined as abnormal (x) only when the joint type is incorrectly selected. The energization was properly stopped before the constant resistance control was reached, and it was possible to prevent the occurrence of quality defects due to incorrect selection of the joint type.

The energization control device and method of the present disclosure are used at the time of fusion work between an electric fusion joint and a pipe.

Claims (9)

A device that controls energization of the heating wire when electric power is supplied to the heating wire of the electric fusion joint to fuse the electric fusion joint and the pipe.
The resistance value of the heating wire of the joint is read before the start of energization of the electrically fused joint, and if the read resistance value is within the range of the resistance values of the plurality of types of joints, the resistance values of the plurality of types of joints are selected. A joint type selection function that allows you to manually select one, and
A basic control function that raises the resistance value of the heating wire to the target resistance value by energization and then holds it at the target resistance value for a certain period of time according to the type of joint selected in the joint type selection function.
The resistance value of the heating wire is in a predetermined resistance value range at the detection time point between the start of energization of the heating wire by the basic control function and the time when the resistance value of the heating wire reaches the target resistance value. When deviating from, the wrong selection judgment function that stops the supply of power to the heating wire and
An energization control device. The energization control device according to claim 1, further comprising a correction function for correcting the resistance value range and / or the detection time point according to the environmental temperature. A device that controls energization of the heating wire when electric power is supplied to the heating wire of the electric fusion joint to fuse the electric fusion joint and the pipe.
The resistance value of the heating wire of the joint is read before the start of energization of the electrically fused joint, and if the read resistance value is within the range of the resistance values of the plurality of types of joints, the resistance values of the plurality of types of joints are selected. A joint type selection function that allows you to manually select one, and
A basic control function that raises the resistance value of the heating wire to the target resistance value by energization and then holds it at the target resistance value for a certain period of time according to the type of joint selected in the joint type selection function.
If the resistance value of the heating wire does not rise to the target resistance value even after a predetermined time point has elapsed after starting the energization of the heating wire by the basic control function, the power to the heating wire is supplied. Misselection judgment function to stop the supply of
An energization control device. The energization control device according to claim 3, further comprising a correction function for correcting the specified time point according to the environmental temperature. It is a method of controlling the energization of the heating wire when the electric fusion joint and the pipe are fused by supplying electric power to the heating wire of the electric fusion joint.
The resistance value of the heating wire of the joint is read before the start of energization of the electrically fused joint, and if the read resistance value is within the range of the resistance values of the plurality of types of joints, the resistance values of the plurality of types of joints are selected. Select one,
When the resistance value of the heating wire is raised to the target resistance value by energization according to the type of the selected joint, from the start of energization of the heating wire to the resistance value of the heating wire reaching the target resistance value. If the resistance value of the heating wire deviates from a predetermined resistance value range at the detection time point between them, the supply of electric power to the heating wire is stopped.
Energization control method. The resistance value range and / or the detection time point is corrected by the environmental temperature.
The energization control method according to claim 5. It is a method of controlling the energization of the heating wire when the electric fusion joint and the pipe are fused by supplying electric power to the heating wire of the electric fusion joint.
The resistance value of the heating wire of the joint is read before the start of energization of the electrically fused joint, and if the read resistance value is within the range of the resistance values of the plurality of types of joints, the resistance values of the plurality of types of joints are selected. Select one,
When the resistance value of the heating wire is raised to the target resistance value by energization according to the type of the selected joint, the resistance value of the heating wire rises to the target resistance value even after a predetermined time point has passed. If not, the power supply to the heating wire is stopped.
Energization control method. The specified time point is corrected by the environmental temperature.
The energization control method according to claim 7. A method for manufacturing a piping member, comprising a step of fusing an electric fusion joint and a pipe by the energization control device according to any one of claims 1 to 4.

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