Induction heating welding device, control method, and control program

Abstract

To provide an induction heating deposition device that can appropriately deposit a waterproof sheet and a waterproof sheet fixing tool even when moisture is present.SOLUTION: An induction heating deposition device 9 comprises: a heating coil 15 that inductively heats a waterproof sheet fixing tool 6; a sensor S; a heating control section that controls an operation of the heating coil; and a boiling determination section that determines whether or not water is boiling under a waterproof sheet 8 based on an output of the sensor S. The heating control section stops an operation of the heating coil after the boiling determination section determines that water is not boiling if the boiling determination section determines that water is boiling. The sensor S is a vibration sensor, a sound sensor, a temperature sensor, or the like.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an induction heating welding device. [Background technology]

[0002] As shown in Patent Document 1, a mechanical fixing method using an induction welding device has been conventionally used in construction work to lay waterproof sheets on flat roofs, etc. In this method, a disk-shaped sheet fixing device with a thermoplastic resin adhesive layer is first anchored to the waterproof substrate. Next, the waterproof sheet is unfolded, and the sheet fixing device is heated from above the waterproof sheet using an induction welding device to fix the waterproof sheet to the sheet fixing device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5385655 Summary of the Invention [Problem to be solved by the invention]

[0004] Because many sheet fixing devices are placed on the waterproofing base at intervals of several tens of centimeters, installation of the sheet fixing devices takes several days. As a result, water may adhere to the surface of the sheet fixing devices due to rain, snow, condensation, etc. before the waterproofing sheet is deployed.

[0005] The area where the waterproof sheet is laid is large, and it is difficult to remove all of the moisture from the surface of the sheet fastener. Therefore, there is a possibility that a waterproof sheet will be placed on top of the moisture-adhered sheet fastener, and the process of fastening the waterproof sheet using an induction heating welding device will be carried out in that state. If the sheet fastener is heated while there is water between the waterproof sheet and the sheet fastener, the temperature of the sheet fastener will not rise sufficiently, and there is a possibility that the waterproof sheet and the sheet fastener will not be properly welded together.

[0006] An object of the present invention is to provide an induction heating welding device that can properly weld a waterproof sheet and a waterproof sheet fastener even when moisture is present. [Means for solving the problem]

[0007] As a means for solving the above-mentioned problems, the induction heating welding device of the present invention is an induction heating welding device that heats a waterproof sheet fastener covered with a waterproof sheet from above the waterproof sheet by electromagnetic induction to weld the waterproof sheet to the waterproof sheet fastener, and is equipped with a heating coil that induction heats the waterproof sheet fastener, a sensor, a heating control unit that controls the operation of the heating coil, and a boiling determination unit that determines whether water is boiling under the waterproof sheet based on the output of the sensor, and is characterized in that when the boiling determination unit determines that water is boiling, the heating control unit stops the operation of the heating coil after the boiling determination unit determines that water is not boiling.

[0008] As a means for solving the above-mentioned problems, the control method of the present invention is a control method for controlling an induction heating welding device that heats a waterproof sheet fastener covered with a waterproof sheet from above the waterproof sheet by electromagnetic induction to weld the waterproof sheet to the waterproof sheet fastener, and is characterized by including a heating start step of starting the operation of a heating coil provided in the induction heating welding device to induction heat the waterproof sheet fastener, a first boiling determination step of determining whether or not water boiling is occurring under the waterproof sheet based on the output of a sensor provided in the induction heating welding device, a second boiling determination step of continuously determining whether or not water boiling is occurring under the waterproof sheet based on the output of the sensor if it is determined that water boiling is occurring in the first boiling determination step, and a heating stop step of stopping the operation of the heating coil after it is determined that water boiling is not occurring in the second boiling determination step.

[0009] As a means for solving the above-mentioned problems, the control program of the present invention is a control program for controlling an induction heating welding device that heats a waterproof sheet fastener covered with a waterproof sheet from above the waterproof sheet by electromagnetic induction to weld the waterproof sheet to the waterproof sheet fastener, and is characterized in that when executed by a computer, the computer executes the following: a heating start process that starts the operation of a heating coil provided in the induction heating welding device to induction heat the waterproof sheet fastener; a first boiling determination process that determines whether water boiling is occurring under the waterproof sheet based on the output of a sensor provided in the induction heating welding device; a second boiling determination process that, if it is determined that water boiling is occurring in the first boiling determination process, continuously determines whether water boiling is occurring under the waterproof sheet based on the output of the sensor; and a heating stop process that stops the operation of the heating coil after it is determined that water boiling is not occurring in the second boiling determination process.

[0010] If water boils while the waterproof sheet fastener is being heated, the temperature of the waterproof sheet fastener will only rise to around 100°C, so if the heating of the waterproof sheet fastener is stopped while the water is boiling, there is a high possibility that the waterproof sheet and the waterproof sheet fastener will not be sufficiently welded together. According to the above characteristic configuration, if it is determined that water is boiling, the operation of the heating coil is stopped after it is determined that water is not boiling, so the operation of the heating coil is stopped and the heating of the waterproof sheet fastener is finished after the water has finished boiling. This prevents the occurrence of a situation where heating is stopped while the temperature rise of the waterproof sheet fastener is being hindered by water boiling, resulting in incomplete welding, and allows the waterproof sheet and the waterproof sheet fastener to be properly welded together even when moisture is present.

[0011] In the present invention, it is preferable that a vibration sensor is provided as the sensor, and the boiling determination unit determines that water is boiling when the magnitude of vibration detected by the vibration sensor is equal to or greater than a predetermined vibration threshold, and determines that water is not boiling when the magnitude of vibration detected by the vibration sensor is less than the vibration threshold.

[0012] When water is present between the waterproof sheet and the waterproof sheet fastener and the water boils as the waterproof sheet fastener is heated, the water vaporizes, causing the waterproof sheet to vibrate. According to the above feature, the output of the vibration sensor can be used to accurately determine whether the water is boiling or not.

[0013] In the present invention, it is preferable that a contact member be provided that comes into contact with the waterproof sheet, and that the vibration sensor detects vibrations of the contact member.

[0014] According to the above feature, since the vibration of the contact member is detected by the vibration sensor, it is possible to accurately determine whether the water is boiling or not.

[0015] In the present invention, it is preferable that a sound sensor is provided as the sensor, and the boiling determination unit determines that water is boiling when the volume of the sound detected by the sound sensor is equal to or greater than a predetermined sound threshold, and determines that water is not boiling when the volume of the sound detected by the sound sensor is less than the sound threshold.

[0016] If there is water between the waterproof sheet and the waterproof sheet fastener, and the water boils as the waterproof sheet fastener is heated, sound will be generated due to the bursting of bubbles, vibration of the waterproof sheet, etc. According to the above features, the output of the sound sensor can accurately determine whether the water is boiling or not.

[0017] In the present invention, it is preferable that a temperature sensor is provided as the sensor, and the boiling determination unit determines whether or not water is boiling based on an output of the temperature sensor.

[0018] If there is water between the waterproof sheet and the waterproof sheet fastener and the water boils as the waterproof sheet fastener is heated, the heat generated by induction heating is consumed to raise the temperature and boil the water, resulting in a different temperature change pattern compared to when there is no water. According to the above features, the presence or absence of boiling water can be accurately determined from the output of the temperature sensor.

[0019] In the present invention, it is preferable that the boiling determination unit determines that water is boiling when the rate of increase in temperature of the waterproof sheet detected by the temperature sensor is below a predetermined increase rate threshold, and determines that water is not boiling when the rate of increase is below the increase rate threshold.

[0020] According to the above feature, since the boiling is determined based on the rate of temperature increase, it is possible to accurately determine whether or not the water is boiling.

[0021] In the present invention, it is preferable that the device further includes a temperature sensor for determining whether to stop the operation of the waterproof sheet, and that the heating control unit stops the operation of the heating coil when the temperature detected by the temperature sensor for determining whether to stop the operation of the waterproof sheet reaches a predetermined set temperature.

[0022] According to the above feature, when water boils, the operation of the heating coil is stopped when the temperature of the waterproof sheet reaches a predetermined set temperature after the boiling has stopped, so that the temperatures of the waterproof sheet fastener and the waterproof sheet rise sufficiently, thereby enabling the waterproof sheet and the waterproof sheet fastener to be more appropriately welded together even when moisture is present. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a vertical cross-sectional view showing an induction heating welding device, a waterproof sheet, and a waterproof sheet fixing tool. [Figure 2] FIG. 10 is a vertical cross-sectional view showing a state in which a waterproof sheet fastener is being heated using an induction heating welding device. [Figure 3] FIG. 2 is a functional block diagram showing a control function of the induction heating welding device. [Figure 4] 10 is a flowchart showing a flow of a heating treatment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of an induction heating welding apparatus, a control method, and a control program according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following embodiment, and various modifications are possible without departing from the spirit and scope of the present invention.

[0025] First, a waterproof sheet bonding method performed using an induction heating welding device 9 will be described with reference to Figures 1 and 2. The waterproof sheet bonding method is a method for waterproofing work in architectural or civil engineering construction, such as waterproofing work for flat roofs, in which a waterproof sheet 8 is laid on a frame such as concrete or metal (hereinafter referred to as waterproof base 4) and fixed to the waterproof base 4.

[0026] [Fixing process, placement process] First, as shown in Figure 1, a process (fixing process) is performed in which a waterproof sheet fixture 6 is fixed to a waterproof base 4, and a process (placement process) is performed in which a waterproof sheet 8 is placed on the fixing surface 6b of the waterproof sheet fixture 6. More specifically, an insulating panel 5 is placed on the waterproof base 4, a waterproof sheet fixture 6 is placed on the insulating panel 5, and the waterproof sheet fixture 6 is fixed to the waterproof base 4 with a fixing member 7. The insulating panel 5 is formed, for example, from an isocyanate foam material and contains countless closed bubbles. It also has adequate strength and thermal insulation properties.

[0027] The waterproof sheet fixture 6 is a member that can be heated by electromagnetic induction, and is made of metal, for example. The waterproof sheet fixture 6 is a flat, plate-shaped member, and in this embodiment, a disk-shaped member. The waterproof sheet fixture 6 has a protruding portion 6a that protrudes upward. The upper surface of the protruding portion 6a is the surface (fixing surface 6b) to which the waterproof sheet 8 is fixed. In this embodiment, the protruding portion 6a is annular, and the fixing surface 6b is annular, having an outer edge 6c and an inner edge 6d. In this embodiment, a hot melt adhesive layer is provided on the fixing surface 6b, and the waterproof sheet 8 is bonded to the waterproof sheet fixture 6 by thermal welding of the hot melt adhesive layer. Note that the waterproof sheet 8 may also be bonded to the waterproof sheet fixture 6 by fusion (melting and solidifying) of the waterproof sheet 8.

[0028] The fixing member 7 includes a tube washer 7a and a screw 7b. In this embodiment, the tube washer 7a is inserted into the central hole of the waterproof sheet fixing device 6, and the tube washer 7a is inserted into the insulation panel 5 from above. The screw 7b is then inserted into the tube washer 7a and screwed into the waterproof base 4, whereby the fixing member 7 fixes the waterproof sheet fixing device 6 to the waterproof base 4.

[0029] The waterproof sheet 8 is a flexible and waterproof sheet made of, for example, vinyl chloride resin.

[0030] [Adhesion process] After the placement step, as shown in Figure 2, a step (adhesion step) is performed in which the waterproof sheet fixture 6 is heated to adhere the waterproof sheet 8 to the waterproof sheet fixture 6. More specifically, the worker holds the induction heating welding device 9 by hand, places the induction heating welding device 9 on top of the waterproof sheet fixture 6 over the waterproof sheet 8, and activates the induction heating welding device 9 to heat the waterproof sheet fixture 6. When the induction heating welding device 9 heats the waterproof sheet fixture 6, the temperature of the hot melt adhesive layer provided on the fixing surface 6b rises and the hot melt adhesive layer softens or melts. This bonds the waterproof sheet fixture 6 and the waterproof sheet 8 together.

[0031] [Pressing process] After the bonding process, a process (pressing process) is carried out in which the waterproof sheet 8 is pressed with a pressing tool to make the waterproof sheet 8 adhere to the waterproof sheet fixing device 6. In detail, the worker holds the pressing tool in his / her hand and places the pressing tool on the waterproof sheet fixing device 6 from above the waterproof sheet 8, thereby pressing the waterproof sheet 8. Pressed by the pressing tool, the waterproof sheet 8 adheres to the waterproof sheet fixing device 6.

[0032] [Induction heating welding equipment] 1, 2, and 3, induction heating welding device 9 includes a case 11, a handle 12, a contact member 13, a switch 14, a heating coil 15, a temperature sensor 16 for determining whether the device is stopped, a buzzer 17, a harness 18, a sensor S, and a control device 80. Induction heating welding device 9 includes a main body (not shown) that includes a power source, an operation unit, etc. Case 11 and the main body are connected by harness 18.

[0033] The case 11 is a cylindrical member.

[0034] The handle 12 is a rod-shaped member that is used by an operator performing the bonding process to hold the induction heat welding device 9. The handle 12 is disposed on the top of the case 11.

[0035] The contact member 13 is a member that comes into contact with the waterproof sheet 8. The contact member 13 is, for example, a disk-shaped member made of silicone rubber. The contact member 13 may be an elastically deformable member or a hard member.

[0036] The switch 14 is an operating tool that receives an operation from an operator to start heating by the heating coil 15. In this embodiment, the switch 14 is a push button located on the top of the case 11. The switch 14 is located in a position that allows it to be operated by the operator's hand while holding the handle 12. The switch 14 is located near the handle 12.

[0037] The heating coil 15 is a flatly wound coil. The heating coil 15 is disposed at the bottom of the case 11. When the induction heating welding device 9 is placed on the waterproof sheet 8 in the bonding process (FIG. 2), the heating coil 15 faces the fixing member 7. An AC voltage is applied to the heating coil 15 by the control device 80, and the fixing member 7 is induction heated.

[0038] The stoppage determination temperature sensor 16 is a temperature sensor. The stoppage determination temperature sensor 16 is disposed near the contact member 13 at the bottom of the case 11. The stoppage determination temperature sensor 16 detects the temperature of the contact member 13, thereby detecting the temperature of the waterproof sheet 8.

[0039] The buzzer 17 is controlled by the control device 80 to notify the operator. For example, the buzzer 17 emits an alarm when the heating coil 15 is operating.

[0040] The harness 18 connects the case 11 to a main body (not shown).

[0041] The sensor S is a sensor that acquires information for determining whether water is boiling under the waterproof sheet 8. In this embodiment, the sensor S is a vibration sensor that is disposed near the contact member 13 at the bottom of the case 11. The sensor S detects vibrations of the contact member 13 that contacts the waterproof sheet 8, and sends an output corresponding to the magnitude of the vibration to the control device 80.

[0042] If water exists between the waterproof sheet 8 and the waterproof sheet fastener 6, and the water boils as the waterproof sheet fastener 6 is heated, the water will evaporate and vibrate, causing the waterproof sheet 8 to vibrate. This will cause the contact member 13 to vibrate, and the sensor S will detect this vibration. In this way, it will be possible to determine whether or not water is boiling under the waterproof sheet 8 based on the output of the sensor S, which is a vibration sensor.

[0043] [Control device] The control device 80 is an ECU, and as shown in Fig. 3, includes a heating control unit 81, a boiling determination unit 82, and an alarm control unit 83. The control device 80 is connected to the sensor S, the switch 14, the heating coil 15, the stop determination temperature sensor 16, and the buzzer 17, and is configured to be able to control these. The control device 80 includes a memory (such as a HDD or non-volatile RAM, not shown) that stores programs and control parameters corresponding to the above-mentioned functional units, and a CPU (computer, not shown) that executes the programs. The functions of each functional unit are realized by the CPU executing the programs. The control device 80 may be configured with multiple ECUs that can communicate with each other.

[0044] The heating control unit 81 controls the operation of the heating coil 15. Specifically, the heating control unit 81 starts and stops the operation of the heating coil 15 by turning on and off the supply of alternating current to the heating coil 15.

[0045] In this embodiment, the heating control unit 81 starts operation of the heating coil 15 in response to operation of the switch 14, and stops operation of the heating coil 15 based on the judgment result of the boiling judgment unit 82, the output of the stop judgment temperature sensor 16, and the passage of time.

[0046] The boiling determination unit 82 determines whether or not water is boiling under the waterproof sheet 8 based on the output of the sensor S. As described above, in this embodiment, the sensor S is a vibration sensor. The boiling determination unit 82 determines that water is boiling when the magnitude of vibration detected by the vibration sensor serving as the sensor S is equal to or greater than a predetermined vibration threshold, and determines that water is not boiling when the magnitude is less than the vibration threshold.

[0047] The heating control unit 81 continues heating when the boiling determination unit 82 determines that water is boiling, and stops operation of the heating coil 15 after the boiling determination unit 82 determines that water is not boiling. In this embodiment, the heating control unit 81 stops operation of the heating coil 15 when the temperature detected by the stop determination temperature sensor 16 reaches a predetermined set temperature. The set temperature is, for example, an appropriate temperature between 30°C and 70°C. The heating control unit 81 may be configured so that the set temperature is automatically set based on the weather and temperature.

[0048] In this embodiment, if the boiling determination unit 82 determines that water is not boiling, the heating control unit 81 stops the operation of the heating coil 15 when the temperature detected by the stop determination temperature sensor 16 reaches a predetermined set temperature, or when a predetermined set time has elapsed since the start of operation of the heating coil 15. The set time is, for example, 10 seconds.

[0049] [Heat Treatment] The heat treatment performed by the induction heat welding device 9 will be described with reference to the flowchart of FIG.

[0050] When the operator operates the switch 14, the heating control unit 81 starts operating the heating coil 15. This starts induction heating of the waterproof sheet fastener 6 (step #01, heating start step, heating start processing). At this time, the heating control unit 81 starts measuring the elapsed time from the start of heating.

[0051] The boiling determination unit 82 determines whether or not water is boiling under the waterproof sheet 8 based on the output of the sensor S provided in the induction heating welding device 9 (step #02, first boiling determination step, first boiling determination process).

[0052] If it is determined that boiling has not occurred (step #02: No), the heating control unit 81 determines whether the temperature of the waterproof sheet 8 has reached the set temperature based on the output of the stop determination temperature sensor 16 (step #03).

[0053] If it is determined that the set temperature has not been reached (step #03: No), the heating control unit 81 determines whether or not a set time has elapsed since the start of heating (step #04).

[0054] If it is determined that the set time has not elapsed (step #04: No), step #02 is executed again.

[0055] If it is determined that the set temperature has been reached (step #03: Yes), or if it is determined that the set time has elapsed (step #04: Yes), the heating control unit 81 stops the operation of the heating coil 15. This ends the induction heating of the waterproof sheet fastener 6 (step #05).

[0056] If it is determined in step #02 that boiling is occurring (step #02: Yes), the boiling determination unit 82 continuously determines whether or not boiling is occurring in water under the waterproof sheet 8 based on the output of sensor S until boiling ends (step #06: No, second boiling determination step, second boiling determination processing).

[0057] If it is determined in step #06 that boiling has ended, i.e., that boiling is not occurring (step #06: Yes), the heating control unit 81 determines whether the temperature of the waterproof sheet 8 has reached the set temperature based on the output of the stop determination temperature sensor 16 (step #07).

[0058] Step #07 is continuously executed until the set temperature is reached (Step #07: No).

[0059] If it is determined that the set temperature has been reached (step #07: Yes), the heating control unit 81 stops the operation of the heating coil 15. This ends the induction heating of the waterproof sheet fastener 6 (step #05, heating stop processing, heating stop step).

[0060] After step #05 is completed, the heating process is completed.

[0061] That is, in the induction heating welding apparatus 9 of this embodiment, if the water does not boil (Step #02: No), heating is stopped (Step #05) when the set temperature is reached (Step #03: Yes) or when a predetermined set time has elapsed (Step #04: Yes).If the water boils (Step #02: Yes), heating continues until the boiling stops (Step #06: No), and after the boiling stops (Step #06: Yes), heating is stopped (Step #05).

[0062] As described above, the induction heating welding device 9 executes a control method including a heating start process in which the operation of the heating coil 15 is started to induction heat the waterproof sheet fastener 6, a first boiling determination process in which it is determined whether or not water is boiling under the waterproof sheet 8 based on the output of the sensor S, a second boiling determination process in which, if it is determined in the first boiling determination process that water is boiling, it continuously determines whether or not water is boiling under the waterproof sheet 8 based on the output of the sensor S, and a heating stop process in which the operation of the heating coil 15 is stopped after it is determined in the second boiling determination process that water is not boiling.

[0063] The above-described control method is realized by the CPU of the control device 80 executing a control program stored in memory. Execution of the control program by the CPU causes the control device 80 to execute a heating start process that starts the operation of the heating coil 15 to induction heat the waterproof sheet fastener 6, a first boiling determination process that determines whether or not water is boiling under the waterproof sheet 8 based on the output of the sensor S, a second boiling determination process that, if it is determined in the first boiling determination process that water is boiling, continuously determines whether or not water is boiling under the waterproof sheet 8 based on the output of the sensor S, and a heating stop process that stops the operation of the heating coil 15 after it is determined in the second boiling determination process that water is not boiling.

[0064] Other Embodiments Other embodiments will be described below. In the following description, the same components as those in the above-described embodiment will be denoted by the same reference numerals, and the description thereof may be omitted.

[0065] (1) In this embodiment, the sensor S is a sound sensor and is disposed near the contact member 13 at the bottom of the case 11. The sensor S detects sound around the case 11 and sends an output corresponding to the volume of the sound to the control device 80.

[0066] If water exists between the waterproof sheet 8 and the waterproof sheet fastener 6, and the water boils as the waterproof sheet fastener 6 is heated, sound will be generated due to the bursting of air bubbles and the vibration of the waterproof sheet 8. This sound is detected by the sensor S. In this way, it is possible to determine whether or not water is boiling under the waterproof sheet 8 based on the output of the sensor S, which is a sound sensor.

[0067] The boiling determination unit 82 determines that water is boiling when the volume of the sound detected by the sound sensor as sensor S is equal to or greater than a predetermined sound threshold, and determines that water is not boiling when the volume of the sound detected by the sound sensor as sensor S is less than the sound threshold.

[0068] (2) In this embodiment, the sensor S is a temperature sensor and is disposed near the contact member 13 at the bottom of the case 11. The sensor S detects the temperature of the contact member 13, thereby detecting the temperature of the waterproof sheet 8, and sends an output corresponding to the temperature to the control device 80.

[0069] If water exists between the waterproof sheet 8 and the waterproof sheet fastener 6 and the water boils as the waterproof sheet fastener 6 is heated, the heat generated by induction heating is consumed to raise the temperature and boil the water, resulting in a different temperature change pattern compared to when there is no water. Sensor S detects the temperature of the waterproof sheet 8. Therefore, it is possible to determine whether water is boiling under the waterproof sheet 8 based on the output of sensor S, which is a temperature sensor.

[0070] The sensor S and the stoppage determination temperature sensor 16 may be separate sensors, or may be a single sensor that serves both purposes.

[0071] The boiling determination unit 82 determines whether or not water is boiling based on the output of the temperature sensor serving as the sensor S. In detail, the boiling determination unit 82 determines that water is boiling when the rate of increase in temperature of the waterproof sheet 8 detected by the temperature sensor serving as the sensor S is equal to or less than a predetermined increase rate threshold, and determines that water is not boiling when the rate of increase is less than the increase rate threshold.

[0072] If there is no water between the waterproof sheet 8 and the waterproof sheet fastener 6, the rate of temperature rise will be relatively large. Now consider the case where water is present between the waterproof sheet 8 and the waterproof sheet fastener 6. Because the specific heat and heat of vaporization of water are relatively large, a relatively large amount of heat is required to heat up and boil (vaporize) the water, so the rate of temperature rise will be relatively small. Therefore, it is possible to determine whether water is boiling based on the rate of temperature rise. When all the water has vaporized and boiling has ended, the rate of temperature rise will be relatively large. Therefore, it is possible to determine whether water has finished boiling based on the rate of temperature rise.

[0073] (3) The boiling determination unit 82 may be configured to determine whether or not water is boiling based on the frequency of vibration detected by a vibration sensor serving as the sensor S. In this case, the vibration threshold is a threshold related to frequency. Alternatively, the boiling determination unit 82 may be configured to determine that water is boiling when the magnitude of vibration in a predetermined frequency range is equal to or greater than a predetermined vibration threshold. This is preferable because it can reduce false detections.

[0074] (4) The boiling determination unit 82 may be configured to determine whether or not water is boiling based on the frequency of the sound detected by the sound sensor serving as the sensor S. In this case, the sound threshold is a threshold related to frequency.

[0075] (5) The boiling determination unit 82 may be configured to determine whether or not water is boiling based on whether or not the temperature detected by the temperature sensor as the sensor S exceeds a predetermined temperature threshold value at a predetermined time after the start of heating.

[0076] (6) The heating control unit 81 may be configured to stop heating after the water has started to boil and has finished boiling based on the time that has elapsed since the boiling ended. More specifically, the heating control unit 81 may be configured to perform step #07 as follows.

[0077] The heating control unit 81 determines whether the time elapsed since it was determined that boiling had ended (step #06: Yes) has exceeded a predetermined end time (step #07). The end time is, for example, 3 seconds.

[0078] Step #07 is continuously executed until the elapsed time exceeds the end time (Step #07: No).

[0079] If it is determined that the elapsed time has exceeded the end time (step #07: Yes), the heating control unit 81 stops the operation of the heating coil 15. This ends the induction heating of the waterproof sheet fastener 6 (step #05, heating stop processing, heating stop step).

[0080] (7) The heating control unit 81 may be configured to stop heating after boiling of water has begun and ended based on the time elapsed since the end of boiling, in addition to when the set temperature is reached. In this case, the heating control unit 81 stops the operation of the heating coil 15 when the temperature detected by the stop determination temperature sensor 16 reaches a predetermined set temperature, or when the time elapsed since it was determined that boiling had ended (step #06: Yes) exceeds a predetermined time limit (e.g., 5 seconds).

[0081] (8) The control device 80 may be configured to be able to change the vibration threshold, sound threshold, rise rate threshold, temperature threshold, set temperature, set time, end time, and time limit based on manual operation received from the operator.

[0082] (9) The control device 80 may be configured to control the buzzer 17 to notify the operator of the following: that boiling is occurring (step #02: Yes), that boiling has finished (step #06: Yes), and that heating has finished (step #05). The notification method is arbitrary, but possible notifications include starting and stopping sound, changing the pitch or volume, the length of the intermittent sound, or the interval between intermittent sounds.

[0083] (10) In the above embodiment, examples have been described in which the sensor S is a vibration sensor, a sound sensor, and a temperature sensor. The sensor S may be a sensor of other types. [Industrial Applicability]

[0084] The present invention is applicable to an induction heating welding device that induction heats a waterproof sheet fastener. [Explanation of symbols]

[0085] 6: Tarpaulin fixing device 8: Waterproof sheet 9: Induction heating welding equipment 13: Contact member 15: Heating coil 16: Temperature sensor for determining stop 81: Heating control unit 82: Boiling determination section S: Sensor

Claims

1. An induction heating welding device that heats a waterproof sheet fastener covered with a waterproof sheet from above the waterproof sheet by electromagnetic induction to weld the waterproof sheet to the waterproof sheet fastener, a heating coil for induction heating the waterproof sheet fastener; A sensor, a heating control unit that controls the operation of the heating coil; a boiling determination unit that determines whether or not water is boiling under the waterproof sheet based on the output of the sensor, The heating control unit is an induction heating welding device that, when the boiling determination unit determines that water boiling is occurring, stops operation of the heating coil after the boiling determination unit determines that water boiling is not occurring.

2. a vibration sensor as the sensor, 2. The induction heating welding device according to claim 1, wherein the boiling determination unit determines that water is boiling when the magnitude of the vibration detected by the vibration sensor is equal to or greater than a predetermined vibration threshold, and determines that water is not boiling when the magnitude of the vibration detected by the vibration sensor is less than the vibration threshold.

3. a contact member that contacts the waterproof sheet; 3. The induction heating welding apparatus according to claim 2, wherein the vibration sensor detects vibration of the contact member.

4. A sound sensor is provided as the sensor, 2. The induction heating welding device according to claim 1, wherein the boiling determination unit determines that water is boiling when the volume of the sound detected by the sound sensor is equal to or greater than a predetermined sound threshold, and determines that water is not boiling when the volume of the sound detected by the sound sensor is less than the sound threshold.

5. a temperature sensor as the sensor, 2. The induction heating welding device according to claim 1, wherein the boiling determining unit determines whether or not water is boiling based on an output from the temperature sensor.

6. The induction heating welding device described in claim 5, wherein the boiling determination unit determines that water is boiling when the rate of increase in temperature of the waterproof sheet detected by the temperature sensor is below a predetermined increase rate threshold, and determines that water is not boiling when the rate of increase is below the increase rate threshold.

7. Further provided is a temperature sensor for determining whether the waterproof sheet is stopped or not, 7. The induction heating welding device according to claim 1, wherein the heating control unit stops the operation of the heating coil when the temperature detected by the stop determination temperature sensor reaches a predetermined set temperature.

8. A control method for controlling an induction heating welding device that heats a waterproof sheet fastener covered with a waterproof sheet from above the waterproof sheet by electromagnetic induction to weld the waterproof sheet to the waterproof sheet fastener, comprising: a heating start step of initiating operation of a heating coil provided in the induction heating welding device to induction heat the waterproof sheet fastener; a first boiling determination step of determining whether or not water is boiling under the waterproof sheet based on an output of a sensor provided in the induction heating welding device; a second boiling determination step of continuously determining whether or not water is boiling under the waterproof sheet based on the output of the sensor when it is determined that water is boiling in the first boiling determination step; a heating stopping step of stopping operation of the heating coil after it is determined in the second boiling determination step that boiling of water is not occurring.

9. A control program for controlling an induction heating welding device that heats a waterproof sheet fastener covered with a waterproof sheet from above the waterproof sheet by electromagnetic induction to weld the waterproof sheet to the waterproof sheet fastener, the control program being executed by a computer to cause the computer to: a heating start process for inductively heating the waterproof sheet fastener by starting the operation of a heating coil provided in the induction heating welding device; a first boiling determination process for determining whether or not water is boiling under the waterproof sheet based on an output of a sensor provided in the induction heating welding device; a second boiling determination process for continuously determining whether or not water is boiling under the waterproof sheet based on the output of the sensor when it is determined that water is boiling in the first boiling determination process; a heating stop process for stopping operation of the heating coil after it is determined in the second boiling determination process that boiling of water has not occurred.

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