JP2018156741A - Controller for electrification of electrofusion joint, electrification control method, and pipe member manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To disclose an electrification controller which can suppress degradation of resin attributed to overheating by a heating wire and occurrence of poor joining owing to unsatisfactory heating.SOLUTION: An electrification controller is a device for controlling electrification of a heating wire of an electrofusion joint when supplying electric power to the heating wire to join the electrofusion joint with a pipe by fusion. The electrification controller comprises: a basic control function of raising, by electrification, a resistance value of the heating wire to a target resistance value and then, keeping the target resistance value for a fixed length of time; and a keeping-control-starting function of starting keeping control of the resistance value of the heating wire at a point of time when the resistance value of the heating wire becomes a value between 90% and 98% of the target resistance value in raising, by electrification, the resistance value of the heating wire to the target resistance value.SELECTED DRAWING: Figure 5

Description

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

  An electric fusion joint is widely used as a joint for connecting resin pipes. In the electric fusion joint, a heating wire is embedded in the inner peripheral surface of the insertion portion (receiving portion) of the pipe to be connected in the joint main body (Patent Document 1, etc.). After inserting the pipe into the receiving portion of the joint body, the joint body and the pipe can be joined by heating the heating wire by energization and melting the vicinity of the joint surface. In this case, it is necessary to control energization to the heating wire by using an energization control device to adjust the heating temperature of the heating wire (Patent Document 2 etc.).

  As an example of the energization control method of the electric fusion joint, for example, there are a method of performing constant voltage control, a method of controlling constant current, and a method of controlling constant power by controlling voltage and current from the start to the end of energization. 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 deterioration of the resin due to overheating or poor bonding 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, etc.). In this method, the temperature of the heating wire is controlled so that the temperature of the resin around the heating wire does not rise or fall too much, thereby suppressing deterioration of the resin due to excessive heating or poor bonding due to insufficient heating. it can.

JP, 2006-035327, A Japanese Patent No. 5637228 JP-A-9-323358 Japanese Patent Laid-Open No. 3-47737 JP-A-64-31624 JP 2001-289388 A

  As a method of keeping the heating wire temperature of the joint constant, the temperature dependency 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. A constant resistance control method in which the temperature is increased to the target resistance value (corresponding to the target temperature) and held at the target resistance value for a certain time is considered effective. In the constant resistance control method, for example, the resistance calculated from the supply voltage value and the current value is successively monitored, and the control is performed so as to adjust the supply power and hold the target resistance value for a certain period of time. However, even with such a constant resistance control method, resin deterioration due to excessive heating or poor bonding due to insufficient heating may occur.

  The change with time of the resistance value of the heating wire in the constant resistance control method is ideally as shown in FIG. That is, it is ideal to increase the resistance value of the heating wire by energization, switch the energization control when the target resistance value is reached, and hold the target resistance value for a certain period of time. However, even if the energization control is switched when the resistance value of the heating wire reaches the target resistance value, the increase in the resistance value of the heating wire cannot be stopped immediately, as shown in FIG. The value overshoots beyond the target resistance value, and the resistance value fluctuates due to the recoil returning toward the target resistance value again. A large change in resistance value means a large change in heating wire temperature. In this respect, in the constant resistance control method, the present inventors can suppress such overshoot and suppress the fluctuation of the resistance value, thereby suppressing the deterioration of the resin due to excessive heating and the bonding failure due to insufficient heating. Thought.

  In order to suppress the above-described overshoot, the present inventors make the rate of increase of the resistance value of the heating wire moderate before the resistance value of the heating wire reaches the target resistance value from the start of energization. It was considered effective to start holding control of the resistance value, and an energization control device having such a holding control start function was prototyped. As a result, the overshoot rate is remarkably reduced only when the resistance value holding control is started at a predetermined time (that is, the above-described overshooting is performed regardless of whether the resistance value holding control start time is too early or too late). It was found that the shooting rate was increased.

Based on the above, this application is one of the means for solving the above-described problems.
An apparatus for controlling energization to the heating wire when supplying electric power to the heating wire of the electric fusion joint to fuse the electric fusion joint and the tube, wherein the resistance value of the heating wire is determined by energization. When the resistance value of the heating wire is raised to the target resistance value by energization, the basic control function that holds the target resistance value for a certain period of time after being raised to the target resistance value, and the resistance value of the heating wire is An energization control device comprising: a holding control start function that starts holding control of the resistance value of the heating wire when the value becomes any value between 90% and 98% of the target resistance value; Disclose.

  The energization control device of the present disclosure monitors the resistance value of the heating wire when the resistance value of the heating wire is increased to the target resistance value by energization and then held at the target resistance value for a certain period of time. It is preferable to provide a resistance value monitoring function for controlling the power supplied to the heating wire so that the resistance value of the heating wire becomes a value between a preset threshold upper limit and threshold lower limit.

This application is one of the means for solving the above-described problems.
A method of controlling energization to the heating wire when supplying electric power to the heating wire of the electric fusion joint to fuse the electric fusion joint and the tube, and the resistance value of the heating wire is determined by energization. The time when the resistance value of the heating wire becomes any value between 90% and 98% of the target resistance value in holding the target resistance value for a certain period of time after being raised to the target resistance value Then, the energization control method which starts holding | maintenance control of the resistance value of the said heating wire is disclosed.

  The energization control method of the present disclosure monitors the resistance value of the heating wire 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. It is preferable to control the electric power supplied to the heating wire so that the resistance value of the heating wire becomes a value between a preset threshold upper limit and a threshold lower limit.

  Moreover, this application discloses the manufacturing method of a piping member provided with the process of fuse | melting an electric fusion joint and a pipe | tube with the electricity supply control apparatus of this indication.

  According to the energization control device and the energization control method of the present disclosure, the holding control of the resistance value of the heating wire is started at a predetermined time before the resistance value of the heating wire reaches the target resistance value. Thereby, it can suppress that the resistance value of a heating wire exceeds a target resistance value, and can suppress the fluctuation | variation of the resistance value of a heating wire. As a result, it is possible to suppress the deterioration of the resin due to excessive heating and the bonding failure due to insufficient heating.

It is a figure for demonstrating the ideal time-dependent change of the heating wire resistance value in constant resistance control. It is a figure for demonstrating the problem of an overshoot. It is a figure for demonstrating a basic control function. It is a figure which shows an example of the time-dependent change of the electric current value of a heating wire, a voltage value, and resistance value by a basic control function. It is a figure for demonstrating a holding | maintenance control start function. It is a figure for demonstrating a resistance value monitoring function. It is a figure for demonstrating a target resistance value correction | amendment function (the 1). It is a figure for demonstrating an output correction function. It is a figure for demonstrating an electricity supply stop function. It is a figure for demonstrating a coupling type selection function. It is a figure for demonstrating the problem which arises at the time of incorrect selection of a joint type. It is a figure for demonstrating a misselection judgment function (the 1). It is a figure for demonstrating the difference in the heating wire resistance value by the difference in environmental temperature (The difference in resistance value at the time of an energization start, the difference in the rising speed after an energization start). It is a figure for demonstrating a resistance value range correction function and a detection time point correction function. It is a figure for demonstrating an incorrect selection judgment function (the 2). It is a figure for demonstrating a target resistance value correction | amendment function (the 2).

1. Energization control device The energization control device of the present disclosure is a device that controls energization to a heating wire when supplying power to the heating wire of the electric fusion joint to fuse the electric fusion joint and the tube. When the resistance value of the heating wire is raised to the target resistance value by energization, the basic control function that holds the target resistance value for a certain period of time after energization and when the resistance value of the heating wire is raised to the target resistance value by energization. A holding control start function that starts holding control of the resistance value of the heating wire when the resistance value of the heating wire reaches any value between 90% and 98% of the target resistance value.

1.1. Basic control function The basic control function is a function of holding the resistance value of the heating wire of the electric fusion joint to the target resistance value by energization and holding the target resistance value for a certain 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 increases, and the temperature of the heating wire corresponds to the target resistance value. Reach a predetermined temperature. Thereafter, the heating wire is held at the target resistance value for a certain time. That is, heat is generated for a certain 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 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 (control to change the voltage with a constant current value) is performed (STEP 1), and then to constant voltage control (to change the current with a constant voltage) (STEP 2) is preferably performed so that the resistance value of the heating wire reaches 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. After performing constant current control in this way, by performing constant voltage control, the supply power increase characteristic accompanying the increase in heating wire resistance value of constant current control and the supply accompanying the increase in heating wire resistance value of constant voltage control Due to the power suppression characteristic, the heating wire resistance value can be slowly and smoothly increased in the vicinity of the target resistance value immediately after the start of energization. On the other hand, constant resistance control (holding control) is performed by gradually decreasing the voltage and current with the passage of time (decreasing supply power) in order to hold the target resistance value for a certain period of time (STEP 3) . Here, in the energization control device of the present disclosure, as described later, the holding control is started before the resistance value of the heating wire reaches the target resistance value. 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 the feedback control are not particularly limited and will be omitted here because they are obvious to those skilled in the art.

  The speed and time for increasing the resistance value of the heating wire, the value of the target resistance value of the heating wire, and the time for holding at the target resistance value are not particularly limited. What is necessary is just to determine suitably according to etc. For example, it is preferable that the time from the start of energization to the start of holding control described later is 5 seconds or more and 15 seconds or less.

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

1.2. Holding control start function As shown in FIG. 2, in the above-described energization control device, even when the supply power is switched so as to hold the resistance value when the resistance value of the heating wire reaches the target resistance value, the heating wire The resistance value rise cannot be stopped immediately, and the resistance value of the heating wire overshoots exceeding the target resistance value, and the resistance value fluctuates due to the recoil returning toward the target resistance value again. End up. From this point of view, the energization control device of the present disclosure has a 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. A holding control start function for starting holding control is provided. Specifically, as shown in FIG. 5, when the resistance value of the heating wire becomes any value between 90% and 98% of the target resistance value, the holding control of the resistance value of the heating wire is performed. Start.

  According to the knowledge of the present inventors, the overshoot rate and the resistance value fluctuation increase regardless of whether the holding control is started too early or too late. As shown in FIG. 5, the overshoot rate is determined by setting the time point at which the holding control is started as the time point when the resistance value of the heating wire becomes any value between 90% and 98% of the target resistance value. For example, the resistance value can be reduced to 2% or less, and the fluctuation of the resistance value can also be reduced to 2% or less, for example. In the energization control device of the present disclosure, preferably, the holding control is started when the resistance value of the heating wire becomes any value between 92.5% and 97.5% of the target resistance value. To do. Thereby, the overshoot and the fluctuation of the resistance value can be further suppressed.

  The holding control of the resistance value of the heating wire can be performed, for example, by gradually reducing the voltage and the current with the passage of time (decreasing the supply power) as in STEP 3 described above. When the holding control is performed by the energization control device of the present disclosure, the supply power 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.

1.3. 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 the constant resistance control is performed, the resistance value of the heating wire is set so that the resistance value of the heating wire does not greatly deviate from the target resistance value. You need to control the value. That is, in the energization control device of the present disclosure, as shown in FIG. 6, 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 time, the resistance value of the heating wire It is preferable to have a resistance value monitoring function for controlling the power supplied to the heating wire so that the resistance value of the heating wire becomes a value between a preset threshold upper limit and threshold lower limit. In this case, it is preferable to correct the upper limit threshold and lower limit threshold of the resistance value according to the environmental temperature, as will be described later.

1.4. Other Functions The energization control device of the present disclosure can further include the following functions in addition to the various functions described above.

1.4.1. Target resistance correction function (part 1)
According to the knowledge of the present inventors, when the energization control to the heating wire is performed by the energization control device having the basic control function as described above, the resistance value of the heating wire is held at the target resistance value for a certain time. When a heating wire short circuit occurs (such as when adjacent heating wires come into contact with each other in a wound heating wire), the resistance value of the heating wire decreases to the target resistance value even though the heating wire resistance drops immediately after the short circuit. Therefore, there is a case where the power supplied to the heating wire becomes excessive and the heating by the heating wire becomes excessive. In order to prevent such a situation, the energization control device of the present disclosure, as shown in FIG. 7, when the heating wire is short-circuited and the resistance value is lowered while holding the target resistance value for a certain time, It is preferable to provide a target resistance value correction function for changing the target resistance value to a resistance value lowered by a short circuit.

  In the target resistance value correction function, for example, while monitoring the resistance value of the heating wire and sequentially performing feedback control to hold the heating wire at the target resistance value, a predetermined time before the measurement time (for example, The resistance value R0 of the heating wire between 0.01 second and 1.0 seconds before) is compared with the current heating wire resistance value R1 at the time of measurement, and the resistance value change over the threshold value between R0 and R1 When (decrease) occurs, it is determined 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 occurrence of the short circuit, and the supply voltage and current to the heating wire are changed so as to satisfy the resistance value R1. The amount by which the supply voltage and current are changed 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 providing 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 canceled) and the resistance value of the heating wire increases (resistance value). Is assumed to be R2 larger than R1). In such a case, if the target resistance value is kept at the resistance value R1, the supply power is insufficient, which causes a fusion failure due to insufficient heating. Therefore, in the energization control device of the present disclosure, the above-described target resistance value correction function is configured to increase the target resistance value to the resistance value R2 when the heating wire short circuit is released and the heating wire resistance value 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 by which the supply voltage and current are changed 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 providing the energization control device with an output correction function described later.

1.4.2. Output correction function As shown in FIG. 8, when the resistance value and the supply voltage before the heating wire are short-circuited are R0 and V0, and the resistance value and the supply voltage after the heating wire are short-circuited are R1 and V1, the supply before the short-circuiting is performed. The electric power W0 and the supplied electric power W1 after the short circuit are expressed by the following equations (1) and (2) from Joule's law and Ohm's law.
W0 = V0 ² / R0 (1)
W1 = V1 ² / R1 (2)

Here, if the supplied power before and after the short circuit is equivalent (W0 = W1), the following relationship is established from the equations (1) and (2).
V0 ² / R0 = V1 ² / R1 (3)

From the above, when the resistance value and the supply voltage before the heating wire are short-circuited are R0 and V0, and the resistance value and the supply voltage after the heating wire are short-circuited are R1 and V1, = V0 × (R1 / R0) It is preferable to provide an output correction function for changing the supply voltage after the short circuit so as to satisfy the relationship of ^1/2 . Thereby, before and after a short circuit, the electric power supplied to a heating wire becomes equivalent, 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 second to 1.0 second). Since R1 <R0 is obvious, it is obvious that V1 <V0.

On the other hand, after the heating wire is short-circuited, when the short-circuit is released and the resistance value of the heating wire increases, the supply voltage is changed as follows by the output correction function. In other words, 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 heating wire is short-circuited are R2 and V2. X (R2 / R1) It is preferable to provide an output correction function for changing the supply voltage after releasing the short circuit so as to satisfy the relationship of ^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 second to 1.0 second). Since R1 <R2 is obvious, it is obvious that V1 <V2.

1.4.3. Energization stop function When the heating wire is held at the target resistance for a certain time, it is assumed that the heating wire is short-circuited multiple times. In this case, the target resistance value is sequentially changed by the above-described target resistance value correction function. However, when the number of shorts of the heating wire is too large, the resistance value is excessively lowered and the arrangement of the heating wires is greatly disturbed, the heating wires are not uniformly heated, which causes poor fusion. Therefore, it is preferable that the energization control device of the present disclosure is provided with the energization stop function described below, so that when the resistance value of the heating wire is excessively decreased, the energization is stopped and the operator is notified of the abnormality.

  That is, as illustrated in FIG. 9, the energization control device of the present disclosure preferably includes an energization stop function that stops energization when the resistance value after a short circuit of the heating wire falls below a threshold value. In this case, the threshold value of the resistance value serving as a reference for stopping energization may be appropriately determined according to the type of the electric fusion joint. Alternatively, the energization may be stopped when the number of times that it is determined that a short circuit has occurred in the heating wire by the target resistance value correction function exceeds a threshold value.

  As described above, the energization control device of the present disclosure includes the basic control function and the target resistance value correction function, thereby controlling the power supplied to the heating wire in response to a short circuit and supplying excess power to the heating wire. It will not be done. Therefore, heating by the heating wire does not become excessive, and stable joint fusion bonding quality can be obtained.

1.4.4. Joint Type Selection Function As shown in FIG. 10, the energization control device of the present disclosure is electrically connected to the electric fusion joint and is capable of energizing the heating wire, and then energizing the electric fusion joint. Before starting, the resistance value of the heating wire of the joint is read (S1), and when the read resistance value is included in the range of the resistance values of the plurality of types of joints (that is, the read resistance value is the resistance of the plurality of types of joints) It is preferable to have a joint type selection function for manually selecting one of the plurality of types of joints (S2). As a result, the energization data is appropriately read in accordance with the type of joint and the supplied power is optimally set, thereby preventing deterioration of the resin due to overheating, poor fusion due to insufficient heating, and the like.

  As shown in FIG. 10, 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 the energization to the electrofusion joint (S1), 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 a plurality of types of joint), the one type of joint is automatically selected (S2). ') It is preferable to further provide a function. As a result, the energization data is appropriately read in accordance with the type of joint and the supplied power is optimally set, thereby preventing deterioration of the resin due to overheating, poor fusion due to insufficient heating, and the like.

1.4.5. Misselection judgment function (part 1)
In the energization control device of the present disclosure, when the type of the electrofusion joint is manually selected by the joint type selection function before the energization of the electrofusion joint is started, the operator erroneously selects the type of the joint. There is a case. In such a case, it is preferable that the energization control device of the present disclosure has a function of stopping energization by determining that the selection of the joint type by the operator is an erroneous selection.

  Basically, a joint having a large nominal diameter (large joint diameter) requires a large amount of power to be supplied because it has a large fusion area. On the other hand, since a joint having a small nominal diameter (small joint diameter) has a small fusion area, a small amount of power is required. Therefore, as shown in FIG. 11, when the type of joint is selected by mistake in manual selection, the power supplied to the joint is different, so that the heating wire resistance value increases from the start of energization. End up. Specifically, when energization is started by selecting a joint with a large nominal diameter for a joint with a small nominal diameter, a larger amount of power than the required power is supplied. The target resistance value is reached. On the other hand, if a joint with a small nominal diameter is selected for a joint with a large nominal diameter and energization is started, only a smaller amount of power than the required supply power is supplied. Takes longer. In the energization control device according to the present disclosure, it is preferable to stop the energization by using this fact to determine an erroneous selection of the joint type of the operator.

  That is, as shown in FIGS. 12A and 12B, the energization control device of the present disclosure is from the start of energization to 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 a predetermined resistance value range at the detection time point, it is preferable to provide an erroneous selection determination function for stopping the supply of power to the heating wire.

  Specifically, when the joint type is selected manually in the above joint type selection function, the operator has a larger nominal diameter (large joint diameter) than a joint having a small nominal diameter (small joint diameter). When a joint is selected, as shown in FIG. 12 (A), after actually starting energization, the supplied power becomes excessive and the resistance value rises faster, so the resistance value of the heating wire at the detection time point is a predetermined value. It will deviate 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 selected an incorrect joint type and stops energization. As a result, energization can be stopped before problems such as overheating occur, and quality defects due to erroneous selection of joint types can be prevented.

  Similarly, when the joint type is selected manually in the joint type selection function described above, a joint with a smaller nominal diameter (small joint diameter) is selected by the operator than a joint with a large nominal diameter (large joint diameter). When selected, as shown in FIG. 12 (B), after actually starting energization, the supply power becomes insufficient and the resistance value rises slowly, so the resistance value of the heating wire at the detection time point is a predetermined resistance value. It will deviate 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 regards the joint type selection by the operator as incorrect and stops energization. As a result, energization can be stopped before problems such as insufficient heating and poor bonding occur, and the occurrence of poor quality due to erroneous selection of joint types can be prevented.

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

  The resistance value range should also be set according to the amount of power to be supplied to the joint, the heating wire resistance rise behavior for each joint type, and the heating wire resistance rise behavior when the joint type 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, it is preferable that the detection time point is set while the heating wire resistance value is increased to the predetermined target resistance value from the start of energization, and the resistance value range is determined at the detection time point. . When the joint type is selected manually in the joint type selection function described above, if the operator correctly selects the joint type, the resistance value of the heating wire is predetermined at the detection time point after actually starting energization. Within the resistance value range. That is, when the resistance value of the heating wire at the detection time point is within a predetermined resistance value range, it is determined that the heating wire is normal, and energization is continued to perform constant resistance control at the target resistance value.

1.4.6. Resistance Value Range Correction Function, Detection Time Point Correction Function As shown in FIG. 13, the heating wire resistance value of the joint before energization varies 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, the energization control device of the present disclosure preferably includes a correction function that corrects the resistance value range and / or the detection time point according to the environmental temperature.

  For example, as shown in FIG. 14A, 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. The value range may be shifted to the low resistance side. Alternatively, as shown in FIG. 14B, 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 preferable to lengthen the time from the start of energization to the detection time point. Thereby, according to the environmental temperature at the time of an operation | work, the misselection of a joint type can be judged appropriately.

Note that 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, be determined based on the following equation Can do.

R _{t1_min_T1} = α × (T1−T0) + R _{t1_min_T0} (T1 ≦ T0) (4)
R _{t1_min_T1} = β × (T1−T0) + R _{t1_min_T0} (T1> T0) (5)
R _{t1_max_T1} = α × (T1−T0) + R _{t1_max_T0} (T1 ≦ T0) (6)
R _{t1_max_T1} = β × (T1−T0) + R _{t1_max_T0} (T1> T0) (7)

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

1.4.7. Misselection judgment function (part 2)
As shown in FIG. 15, the energization control device of the present disclosure is such that the resistance value of the heating wire becomes the target resistance value even after a predetermined time point has elapsed after starting energization of the heating wire by the basic control function. It is preferable to provide an erroneous selection determination function for stopping the supply of electric power to the heating wire when it does not rise to the upper limit.

  The specified time point may be after the time point for switching to constant resistance control. That is, if the resistance value of the heating wire does not reach the target resistance value even though the time point when switching to constant resistance control is exceeded, the energization to 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 heating wire resistance rise behavior for each joint type, and the heating wire resistance rise behavior when the joint type is selected incorrectly. .

  For example, as shown in FIG. 15, even if the heating wire resistance value at the detection time point is within a predetermined resistance value range, the heating wire resistance value is a predetermined target resistance value even after a specified time point has passed. May not rise. In this case, the selection of the joint type in the joint type selection function is regarded as incorrect by the erroneous selection determination function, and the power supply to the heating wire is stopped, so that the power supply is stopped before problems such as insufficient heating and poor bonding occur. It is possible to prevent the occurrence of poor quality due to erroneous selection of joint types.

1.4.8. Specified time point correction function Even in this case, it is preferable to provide a correction function for correcting the above-mentioned specified time point by the environmental temperature. The operation and effect of such a correction function is as described above, and a description thereof is omitted here. The method for correcting the specified time point according to the environmental temperature is not particularly limited.

1.4.9. Target resistance correction function (Part 2)
If the heating wire resistance value as an alternative value of the heating wire temperature is the same target resistance value when the environmental temperature at the time of work is different, the reaching heating wire temperature will be the same, but due to the influence of the environmental temperature, Heat dissipation to the outside environment is promoted and the temperature at the bonding interface is difficult to increase. In high temperature environments, heat dissipation to the outside environment is suppressed and the temperature at the bonding interface is likely to rise. May change. In consideration of 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 illustrated in FIG. In other words, when the environmental temperature is lower than the reference temperature, the target resistance value is corrected to be higher than the reference temperature, and when the environmental temperature is higher than the reference temperature, the target resistance value is corrected to be lower than the reference temperature. Is preferred.

Regarding the correction of the target resistance value, for example, the target resistance value at the reference temperature T0 (for example, 25 ° C.) is R _max and the target resistance value corrected according to the environmental temperature T1 is R _max ′, based on the following formula: It can be implemented.
R _max ′ = [1+ (T0−T1) × γ] × R _max (when T1 ≦ T0) (8)
R _max ′ = [1+ (T0−T1) × δ] × R _max (when T1> T0) (9)

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

  The target resistance value may be corrected only when the difference between the environmental temperature and the reference temperature is equal to or greater than a threshold value.

1.4.10. Supply power correction function When the supply power 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. 2). There is a risk that. In addition, 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 is insufficient and it takes 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 being raised to the target resistance value by energization according to the target resistance value corrected by the target resistance value correction function. It is preferable to provide a supply power correction function. Thereby, as shown in FIG. 16, after the start of energization, the resistance value of the heating wire can be smoothly reached to the corrected target resistance value.

The power supplied to the heating wire when increasing the resistance value of the heating wire is corrected by a function using the environmental temperature so as to be linked with the corrected target resistance value, or a function using the corrected target resistance value. Can be corrected. For example, when the power supplied to the heating wire (the corrected supply power) 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)
As described above, the corrected supply power W can be set. In Equation (10), A and B are correction coefficients.

  In addition, even if the heating wire resistance value at the detection time point is within a predetermined resistance value range by combining the erroneous selection determination function (part 1 and / or part 2) with this resistance value monitoring function, When an abnormal excess or deficiency occurs in the resistance value increase after passing through the time point, it can be detected by the resistance value threshold upper limit and the threshold lower limit, so that the occurrence of poor quality can be more effectively prevented.

1.5. Other obvious configuration The energization control device of this indication should just be constituted so that energization to the heating wire of an electric fusion joint is possible, and it has the above-mentioned various functions. A person skilled in the art can easily implement the energization control device of the present disclosure by referring to the present application. For example, the power supply, the various measuring means (voltage measuring means, current measuring means, etc.), the various switching means, the control circuit, etc. are combined to create a program so that the above-described functions are performed. The control device can be manufactured.

  In addition, the electricity supply control apparatus of this indication controls the resistance value of a heating wire as mentioned above, and presupposes measuring the resistance value of a 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 heating wire. For example, it is preferably 0.3Ω or more and 5.0Ω or less. Although the measurement accuracy of the resistance value is not particularly limited, it is preferably within ± 30 mΩ when the measured resistance value is low (eg, 0.3Ω to 1.5Ω), and the measured resistance value is In the case of high (for example, more than 1.5Ω and not more than 5Ω), it is preferably within ± 2.0%.

  As described above, the resistance value of the heating wire varies 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 measure the environmental temperature together 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. It is preferable to be configured to notify the operator of that via the above.

  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 that the widest possible range can be measured in consideration of the storage temperature and the like. For example, it is preferably set to −20 ° C. or more and 60 ° C. or less. The ambient temperature during use can be measured by a temperature sensor.

2. Electric Fusion Joint There are no particular limitations on the type of electric fusion joint whose energization is controlled by the energization control device of the present disclosure. Any conventionally known electric fusion joint can be applied. Hereinafter, an example of an electrofusion joint will be described.

  The 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 energization terminals and energization via the energization terminals. Heating wire. The “receiving part” refers to a part where a pipe can be inserted and the pipe and the electric fusion joint can be joined. The “joint body” is not particularly limited as long as it has a receiving portion and can connect a pipe as a joint. The “inner peripheral surface of the receiving portion” refers to 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. It is preferable that the heating element is provided so as to cover the entire inner peripheral surface of the receiving port.

2.1. Joint body shape and size (nominal diameter)
The joint body may have any shape as long as 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, any of known shapes such as a cheese type, a socket type, an elbow type, a reducer type, and a cap type can be adopted. Further, the nominal diameter (caliber) of the joint is not particularly limited. For example, the diameter may be 5 mm or more and 250 mm or less.

2.2. Material of Joint Body The material of the joint body may be any material that can be connected to a pipe and can exhibit performance as an electrofusion joint. The same material as the joint body of the conventional electric fusion joint can be used. In particular, considering moldability, mechanical properties, durability, and the like, those made of a crosslinked thermoplastic resin are preferred, and those made of a crosslinked polyethylene are particularly preferred.

2.3. Heating wire 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, Cu wire, Fe wire, or the like is used as the heating wire, the resistance value changes sharply 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 a heating wire is not specifically limited, What is necessary is just to be suitably determined according to the shape and performance of an electrofusion joint. In the present application, the heating wire includes a “pattern made of a metal thin film”. For example, a pattern obtained by patterning a metal foil by punching, etching, or the like corresponds to the heating wire referred to in the present application.

3. Energization control method The energization control method of the present disclosure is a method of controlling energization to a heating wire when power is supplied to the heating wire of the electric fusion joint to fuse the electric fusion joint and the tube. When the resistance value of the heating wire is raised to the target resistance value by energization and held at the target resistance value for a certain time, the resistance value of the heating wire is between 90% and 98% of the target resistance value. When the value reaches the value, the holding control of the resistance value of the heating wire is started.
In such an energization control method, when the resistance value of the heating wire is increased 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 monitored, It is preferable to control the power supplied to the heating wire so that the resistance value is a value between a preset threshold upper limit and threshold lower limit.

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

  In addition, it can be said that the electricity supply control method of this indication controls electricity supply to the heating wire of an electric fusion joint by operation corresponding to various functions of the above-mentioned electricity supply control device. That is, in the energization control method of the present disclosure, the above 1. Any of the operations corresponding to the various functions described in can be incorporated.

4). Manufacturing method of piping member A pipe is inserted into a receiving portion of a joint body of an electric fusion joint, and a heat transfer wire is heated by energization by an energization control device of the present disclosure to melt the vicinity of the joint surface. Can be connected. The piping member obtained in this way can be applied to a hot water supply and hot water supply facility and system by being connected to a hot water heater or the like, for example. Since it is obvious for those skilled in the art about water supply hot water supply equipment and a system, description is abbreviate | omitted here.

  Hereinafter, the effects of the energization control device and method for the electrical fusion joint of the present disclosure will be described in more detail based on examples and comparative examples.

1. Comparative Example Using an energization control device that has the above-described “basic control function” but does not have a “holding control start function”, the electrofusion joint (nominal diameter: 13 mm) is energized, and the energization starts for 10 seconds. After performing constant current control (STEP 1) and constant voltage control (STEP 2) to increase the resistance value of the heating wire to reach the target resistance value (2.064Ω), 30 seconds (from the start of energization) Constant resistance control (holding control) was performed (from 10 seconds to 40 seconds) to hold the resistance value of the heating wire so as to approach the target resistance value (2.064Ω), and then energization was terminated. The resistance value overshoot rate and resistance value fluctuation (resistance value fluctuation after overshoot) after holding control was confirmed. The results are shown in Table 1 below. Note that the fluctuation of the overshoot ratio and the resistance value is determined by the following equations.

(Overshoot rate) = 100 × [(resistance value at the time of overshoot peak) − (average resistance value at constant resistance control)] ÷ (average resistance value at constant resistance control)

(Change in resistance value) = 100 × [(Average value of resistance value during constant resistance control) ± 3σ] / (Average value of resistance value during constant resistance control)

  The average resistance value during the constant resistance control is measured every 0.1 seconds during the 20 seconds before the end of the constant resistance control in which the overshoot peak was not observed in the entire constant resistance control time of 30 seconds. The average value of the resistance values.

2. Example The disclosure time of holding control is as follows: (1) When the resistance value of the heating wire reaches 97.5% of the target resistance value, (2) The resistance value of the heating wire reaches 95.0% of the target resistance value (3) When the resistance value of the heating wire reaches 92.5% of the target resistance value, (4) When the resistance value of the heating wire reaches 90.1% of the target resistance value, In each case, similar to the comparative example, the resistance value overshoot rate and the resistance value variation after the start of the holding control were confirmed. The results are shown in Table 1 below.

  As is apparent from the results shown in Table 1, when the start time of the holding control is set to the time when the target resistance value is reached, the fluctuations in the overshoot rate and the resistance value are large. On the other hand, when the holding control is started before the target resistance value is reached, fluctuations in the overshoot rate and the resistance value can be reduced. From the above results, it is assumed that the start time of the holding control is “when the resistance value of the heating wire becomes any value between 90% and 98% of the target resistance value”. Variation can be suppressed. In particular, when the holding control start time is set to “when the resistance value of the heating wire becomes any value between 92.5% and 97.5% of the target resistance value”, it is more significantly exceeded. The fluctuation of the chute and the resistance value can be suppressed.

  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 (5)

When supplying electric power to the heating wire of the electric fusion joint to fuse the electric fusion joint and the pipe, the device for controlling energization to the heating wire,
A basic control function for holding the target resistance value for a certain time after increasing the resistance value of the heating wire to the target resistance value by energization; and
When raising the resistance value of the heating wire to the target resistance value by energization, when the resistance value of the heating wire becomes any value between 90% and 98% of the target resistance value, Holding control start function to start holding control of resistance value of heating wire;
An energization control device. When the resistance value of the heating wire is increased 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 monitored, and the resistance value of the heating wire is set in advance. A resistance value monitoring function for controlling the power supplied to the heating wire to be a value between the threshold upper limit and the threshold lower limit,
The energization control apparatus according to claim 1. When supplying electric power to the heating wire of the electric fusion joint to fuse the electric fusion joint and the tube, the method of controlling the energization to the heating wire,
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 between 90% and 98% of the target resistance value. When the value becomes any one of the above, start holding control of the resistance value of the heating wire,
Energization control method. When the resistance value of the heating wire is increased 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 monitored, and the resistance value of the heating wire is set in advance. Controlling the power supplied to the heating wire to be a value between the threshold upper limit and the threshold lower limit,
The energization control method according to claim 3. The manufacturing method of a piping member provided with the process of fuse | melting an electric fusion joint and a pipe | tube with the electricity supply control apparatus of Claim 1 or 2.

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