JP6907150B2 - Leakage detector - Google Patents

Description

The present invention relates to the structure of a liquid leakage detection device, particularly the structure of a liquid leakage detection device using a constant current element.

As a method of detecting the occurrence of liquid leakage from air conditioners, etc., when a current is passed through a liquid leakage detection band in which two conductors are arranged in parallel in a non-conducting state, and liquid leaks enter between the two conductors. A method of detecting liquid leakage by detecting a short circuit is used.

However, with such a leak detection method, although the leak can be detected, the leaked portion cannot be detected. Therefore, using a detection sensor in which a plurality of resistance elements are connected in series via a conducting wire and a detection band in which the detection sensor and a conducting wire arranged in parallel are connected by a terminating resistor, a change in the energization resistance of the detection band due to liquid leakage is used. A leak position detector that detects a leak location has been proposed (see, for example, Patent Document 1).

In addition, a leak detector has been proposed in which two sensor cords are arranged in parallel, constant current sources are connected to both ends of the sensor cord, and the leak location is detected based on the voltage difference between both ends of the sensor cord. (See, for example, Patent Document 2).

Jikkai Sho 63-101842A Japanese Unexamined Patent Publication No. 3-9256

By the way, the resistance value is often detected by detecting the current value when a minute voltage is applied to the resistance. The detection sensor of the liquid leakage detector described in Patent Document 1 is one in which a plurality of fixed resistors are connected in series, and when liquid leakage occurs at a position close to the power supply, the change in the detected current value is large. , If a liquid leak occurs at a position far from the power supply, the change in the detected current value becomes small. The energization resistance of water when a liquid leak occurs is not always constant, and the detected current value changes as the energization resistance changes. When a liquid leak occurs at a position far from the power supply, the change in the detected current value is buried in the change in the current value due to the variation in the energization resistance of water, which may make it difficult to detect the leaked part. As described above, the conventional liquid leakage detector has room for improvement in the detection reliability of the leaked portion.

Further, in the liquid leakage detector described in Patent Document 2, it is necessary to connect a constant current source to both ends of the sensor cord, and the voltage difference is detected by a differential amplifier, which complicates the configuration. There was a problem.

Therefore, it is an object of the present invention to improve the detection reliability of the leaked portion with a simple configuration.

The liquid leakage detection device of the present invention is composed of a pair of conductive wires, a liquid leakage detection band in which a current flows when a leak comes into contact between the conductive wires, and a liquid leakage detection band connected to the liquid leakage detection band. A leakage detection unit in which a plurality of leakage detection units including a node having a constant current element that limits the current current value of the current to the current limit value, and a liquid leakage detection unit connected in series to the start end of the liquid leakage detection unit are connected to the above. A power supply that applies a voltage to the liquid leakage detection unit, a current detection unit that detects the energization current value of the liquid leakage detection unit, and the liquid leakage detection unit in which a liquid leak occurs from the energization current value detected by the current detection unit. Each of the constant current elements of each of the leak detection units is provided with a determination unit for determining the current value, and the determination unit is different from the energization current value detected by the current detection unit. It is characterized in that the leak detection unit in which the leak has occurred is identified by comparing with the current limit value of the current element.

In this way, a plurality of leak detection units including constant current elements having different current limit values are connected in series, and the energization current value detected by the current detector is compared with the limit current value of the constant current element to compare the leak. By identifying the leak detection unit that has occurred, it is possible to improve the detection reliability of the leak location.

In the liquid leakage detection device of the present invention, the node of the liquid leakage detection unit includes a pair of start end side terminals, a pair of terminal side terminals to which the pair of conductive wires of the liquid leakage detection band are connected, and the above. Even if the constant current element includes a pair of connecting lines for connecting the start end side terminal and the end end side terminal in parallel, and the constant current element is arranged so as to be interposed between either one or both of the connection lines. good.

In this way, since the arrangement of the constant current elements of the node can be variously changed according to the liquid to be detected, it is possible to detect the leak according to the liquid to be detected.

In the liquid leakage detection device of the present invention, the current limit value of the constant current element of each liquid leakage detection unit may decrease according to the connection order from the start end to the end connected to the power supply.

Since the current limit value of the constant current element of the liquid leakage detection unit decreases according to the connection order from the start end to the end connected to the power supply, the current current value flowing through the liquid leakage detection unit when a liquid leak occurs is the leakage current value. This is the current limit value of the constant current element of the leak detection unit where the liquid is generated. Therefore, the leak detection unit in which the leak has occurred can be identified based on the energization current value detected by the current detection unit.

In the liquid leakage detection device of the present invention, the determination unit has a difference between the energization current value detected by the current detection unit and the current limit value of the constant current element of one liquid leakage detection unit within a predetermined range. In this case, one of the leak detection units may be specified as a leak occurrence location.

As a result, even if there is a difference between the energizing current value detected by the current detector and the current limit value of one constant current element, the leaked part can be specified, and the detection reliability of the leaked part can be improved. Can be done.

In the liquid leakage detection device of the present invention, the determination unit may determine liquid leakage detection when the energization current value detected by the current detection unit is equal to or greater than a predetermined value.

As a result, the occurrence of liquid leakage can be detected even when the difference between the energizing current value detected by the current detection unit and the current limit value of the plurality of constant current elements is not within a predetermined range for some reason. ..

In the liquid leakage detection device of the present invention, when the determination unit determines that the liquid leakage is detected, the determination unit changes the output voltage of the power supply, and the current detection unit determines the amount of change in the energizing current value of the liquid leakage detection unit. It may be detected and it may be determined whether or not the leak detection unit in which the leak has occurred can be identified from the energizing current value based on the change amount. At this time, the determination unit may determine that the leak detection unit in which the leak has occurred can be identified from the energized current value when the absolute value of the change amount is less than a predetermined first threshold value. , The slope of the voltage-current characteristic of the liquid leakage detection unit is calculated based on the amount of change in the output voltage of the power supply and the amount of change in the energizing current value detected by the current detection unit, and the slope is a predetermined second threshold value. If it is less than, it may be determined that the leak detection unit in which the leak has occurred can be identified from the energizing current value. Then, when it is determined from the energization current value detected by the current detection unit that the leak detection unit in which the leak has occurred can be identified, the energization current value detected by the current detection unit and one of the leaks When the difference between the detection unit and the current limit value of the constant current element is within a predetermined range, one said leak detection unit may be specified as a leak occurrence location.

In this way, the output voltage of the power supply is changed, the current detection unit detects the energizing current value of the liquid leakage detection unit, and the constant voltage of the liquid leakage detection unit is based on the amount of change in the energizing current value detected by the current detection unit. After it is determined that the element is saturated and it is possible to identify the leak detection unit where the leak has occurred from the current current value, the current current value detected by the current detector and the determination of one leak detection unit. When the difference from the current limit value of the current element is within a predetermined range, one leak detection unit is specified as the leak occurrence location, so that it is possible to prevent the leakage occurrence location from being erroneously identified. ..

In the liquid leakage detection device of the present invention, the current limit value of the constant current element of the liquid leakage detection unit becomes smaller in equal difference series according to the connection order from the start end to the end connected to the power supply, and the determination is made. When the difference between the energizing current value detected by the current detection unit and the current limit value of the constant current element of the liquid leakage detection unit is within a predetermined range, the unit is one of the liquid leakage detection units. May be specified as the location where the leak occurs. Further, the current limit value of the constant current element of the liquid leakage detection unit may be geometrically reduced according to the connection order from the start end to the end connected to the power supply.

In this way, by reducing the current limit value of the constant current element in an equidistant series according to the connection order from the start end to the end, the accuracy with respect to the limit current value of the constant current element is set as an absolute value, and the current detector unit. By the difference between the energizing current value detected in 1 and the current limiting current value of one constant current element, the predetermined range when specifying the leakage point can be made constant by an absolute value. Further, by making the geometric progression smaller, the accuracy of the constant current element with respect to the current limiting value can be set as a relative value or a ratio, and the current current value detected by the current detection unit is limited to one constant current element. A predetermined range for specifying the leak location by the difference in the current value can be made constant by a relative value or a ratio.

In the liquid leakage detection device of the present invention, the constant current element of the liquid leakage detection unit differs from the positive current limit value and the negative current limit value, the power source is an AC power source, and the determination unit is , The amount of current-carrying charge in the positive direction and the amount of current-carrying charge in the negative direction of the alternating current output from the power source may be equal.

As a result, it is possible to suppress the occurrence of electrolytic corrosion in the leak detection zone when a leak occurs.

In the liquid leakage detection device of the present invention, the liquid leakage detection device is composed of a pair of the conductive wires, includes a start-end side leak detection band through which a current flows when a leak comes into contact between the conductive wires, and the power source is the start-end side leak detection. It is connected to the start end of the liquid leakage detection unit via a band, and in the determination unit, the energizing current value detected by the current detection unit is the maximum value of the current limit value of the constant current element of the liquid leakage detection unit. If it is larger than the above, the leakage detection zone on the starting end side may be specified as the leakage occurrence location.

With this configuration, it is possible to detect liquid leakage between the liquid leakage detection unit and the power supply.

The liquid leakage detection device of the present invention is composed of a pair of conductive wires, a start-end side leak detection band through which a current flows when a leak comes into contact between the conductive wires, and a pair of the conductive wires of the conductive wire. The current value of the terminal-side leak detection band, which is connected between the terminal-side leak detection band and the terminal-side leak detection band, and the terminal-side leak detection band, through which a current flows when a leak comes into contact with the terminal. A leakage detection unit including a node having a constant current element that limits the current to a limit current value, a power supply connected to the start end side leakage detection band and applying a voltage to the leakage detection unit, and the leakage. Whether the current detection unit that detects the energization current value of the liquid detection unit or the end side leakage detection band or the end side leakage detection band has leaked from the energization current value detected by the current detection unit. A liquid leakage detection device including a determination unit for determining the above, wherein the current current value detected by the current detection unit is larger than the current limit value of the constant current element of the liquid leakage detection unit. In this case, the leakage detection band on the starting end side is specified as the leakage occurrence location, and when the energizing current value detected by the current detection unit is equal to or less than the current limit value of the constant current element of the leakage detection unit, It is characterized in that the terminal side leakage detection band is specified as a leakage occurrence location.

Thereby, with a simple configuration, it is possible to identify whether the leak occurrence location is in the start side leak detection band or the end side leak detection band.

In the liquid leakage detection device of the present invention, the node of the liquid leakage detection unit has a pair of start end side terminals to which the pair of conductive wires of the start end side liquid leakage detection band are connected, and the end side leak detection. The constant current element includes a pair of end-side terminals to which the pair of conductive wires of the band are connected, and a pair of connection wires for connecting the start-end side terminal and the end-side terminal in parallel. It may be arranged so as to intervene in one or both of the connecting lines.

In this way, since the arrangement of the constant current elements of the node can be variously changed according to the liquid to be detected, it is possible to detect the leak according to the liquid to be detected.

INDUSTRIAL APPLICABILITY The present invention can improve the detection reliability of a leaked portion with a simple configuration.

It is a system diagram which shows the structure of the liquid leakage detection apparatus of embodiment. It is a system diagram which shows the structure of the liquid leakage detection unit of the liquid leakage detection apparatus shown in FIG. It is a graph which shows the change of the terminal current and the terminal resistance with respect to the terminal voltage of an ideal constant current diode. It is a graph which shows the characteristic of the current with respect to the voltage of the constant current element which connected the constant current diode shown in FIG. 3 in anti-series. It is a graph which shows the characteristic of the current with respect to the voltage of the constant current element which connected the constant current diode shown in FIG. 3 in anti-series and has a different current limit value. It is a system diagram which shows the change of the current flow and voltage when the leakage is detected by the leakage detection apparatus shown in FIG. It is a graph which shows the operating point of each constant current element when the leakage is detected by the leakage detection apparatus shown in FIG. It is a graph which shows the change of the voltage with respect to the leakage detection unit number when the leakage is detected by the leakage detection apparatus shown in FIG. It is a flowchart which shows the operation of the liquid leakage detection apparatus shown in FIG. It is a graph which shows the time change of the detection current and the start voltage at the time of detecting the leakage by the leakage detection apparatus shown in FIG. It is a system diagram which shows the change of the current flow and voltage at the time t3 shown in FIG. It is a graph which shows the change of the voltage with respect to the detection unit number at time t3 shown in FIG. It is a graph which shows the operating point of each constant current element at time t3 shown in FIG. It is a graph which shows the change of the energizing current value when the output voltage of a power source is changed in the non-saturated state of all constant current elements. It is a graph which shows the change of the energizing current value when the output voltage of a power source is changed in the saturated state of any one constant current element. It is a figure which shows the example of the node applied to the liquid leakage detection apparatus of the embodiment shown in FIG. It is a graph which shows the characteristic of the current with respect to the voltage of the constant current element which the limit current value in a positive direction and the limit current value in a negative direction are different. It is a figure which shows the waveform of the output current of the power source when the liquid leakage detection apparatus of another embodiment is configured by using the constant voltage element of the voltage-current characteristic shown in FIG. It is a figure which shows the change of the limit current value with respect to the detection unit number when the limit current value of a constant current element changes arithmetic progression. It is a figure which shows the change of the limit current value with respect to the detection unit number when the limit current value of a constant current element changes geometrically. It is a system diagram which shows the structure of the liquid leakage detection apparatus of another embodiment. It is a system diagram which shows the structure of the liquid leakage detection apparatus of another embodiment. It is a flowchart which shows the operation of the liquid leakage detection apparatus shown in FIG. It is a system diagram which shows the structure of the liquid leakage detection apparatus of another embodiment. It is a flowchart which shows the operation of the liquid leakage detection apparatus shown in FIG. It is a system diagram which shows the structure of the liquid leakage detection apparatus of another embodiment. It is a flowchart which shows the operation of the liquid leakage detection apparatus of embodiment shown in FIG.

<Configuration of leak detection device>
Hereinafter, the liquid leakage detection device 100 of the embodiment will be described with reference to the drawings. As shown in FIG. 1, the liquid leakage detection device 100 includes a liquid leakage detection unit 70, a power supply 81 connected to a start end 71 of the liquid leakage detection unit 70, and a current for detecting the energization current value of the liquid leakage detection unit 70. It is composed of a current sensor 82 which is a detection unit and a determination unit 90 which determines a leak based on the energization current value detected by the current sensor 82.

As shown in FIG. 1, the liquid leakage detection unit 70 is formed by connecting a plurality of liquid leakage detection units U _{1 to} U ₅ in series. With reference to FIG. 2, the detection unit number N indicating the connection order from the start end 71 of the leak detection units 70 of _{the leak detection units U 1 to} U _{5 is m (N = m), that is, the mth from the start end 71.} description will be given of a configuration of the leak detection unit U _m.

As shown in FIG. 2, the _{liquid leakage detection unit U m} has a node ND _m including a constant current element D _m and a liquid leakage detection band 60 including a pair of conductive wires 61 and 62. The node ND _m connects a pair of start end side terminals 13, 15 and a pair of end side terminals 14, 16 and a pair of connection lines 12 connecting the start end side terminals 13, 15 and the end end side terminals 14, 16 in parallel. Includes. _{As shown in FIG. 2, a constant current element D m} is interposed between the connection lines 12 connecting one of the start end side terminals 13 and the end end side terminals 14. Further, the other start end side terminal 15 and the end end side terminal 16 are connected by a connection line 12, and the constant current element D _m is not connected. A pair of conductive wires 61 and 62 of the liquid leakage detection band 60 are connected to the pair of terminal terminals 14 and 16, respectively, and the end portions 61e and 62e of the pair of conductive wires 61 and 62 on the terminal side are leaking liquid. the distal end of the sensing unit U _m. Further, the pair of the starting side terminals 13 and 15, the starting end of the leak detection unit U _m. In this way, the liquid leakage detection unit 70 directs the liquid leakage detection unit U _m including the node ND _{m in which the constant current element D m} is arranged between the connection lines 12 on the side of the conductive wire 61 from the start end 71 to the end end 72. It is connected in series.

Constant current element D _m is an element that limits the energizing current value of the leak detection zone 60 of the leak detection unit U _m to limit current value. Limit current value Ip _m of constant current element D _m are different, it is configured to be smaller in accordance with the connection order directed from the starting end 71 of the leak detection unit 70 connected to the power supply 81 to the terminal 72. In other words, small limit current value Ip _m according detecting unit number N indicating the connection order from a start end 71 of the leak detection part 70 of the leak detection unit _U 1 ~U ₅ increases _{(Ip m> Ip m + 1} ). In the liquid leakage detection device 100 of the present embodiment, the constant current element D _m is configured by connecting the constant current diodes 11a and 11b in anti-series with the anodes facing each other. The configuration of the constant current element D _m will be described in detail later.

The conductive wires 61 and 62 are non-conducting when there is no liquid leakage, and are mutually conductive due to the liquid leakage when the liquid leakage occurs. The conductive wires 61 and 62 may be made of, for example, twisted copper wires covered with a hygroscopic insulating film or the like.

As shown in FIGS. 1 and 2, leak detection unit 70, leak detection unit _{U m} of the distal end portion at which the end portion of the distal side of the conductive wires 61, 62 61e, leak detection units 62e It is configured by sequentially connecting to the start end side terminals 13 and 15 which are the end ends on the start end side of U _{m + 1.} Then, the start end side terminals 13 and 15 of the leak detection unit U _{1 first from} the start end 71 of the liquid leakage detection unit 70 constitute the start end 71 of the liquid leakage detection unit 70, and start from the start end 71 of the liquid leakage detection unit 70. The terminal ends 61e and 62e of the conductive wires 61 and 62 of the _fifth liquid leakage detection unit U5 form the terminal 72 of the liquid leakage detection unit 70. _{The start end side terminals 13 and 15 of the liquid leak detection unit U 1} constituting the start end 71 of the liquid leak detection unit 70 are connected to the power supply 81 via an insulating coated wire 63. A current sensor 82 is connected between the power supply 81 and _one of the start end side terminals 13 of the liquid leakage detection unit U1. Further, the end 72 of the liquid leakage detection unit 70 is open.

The power supply 81 is an AC constant voltage power supply that outputs a predetermined voltage value V0. The power supply 81 may be, for example, an AC 100 Hz and an output voltage of about 10 V. The current sensor 82 is an alternating current detector that detects an alternating current value. The determination unit 90 is a computer including a CPU 91, a memory 92, an input interface 93 to which the power supply 81 and the current sensor 82 are connected, and an output interface 94 that outputs the calculation result of the CPU 91. The CPU 91, the memory 92, the input interface 93, and the output interface 94 are connected by a data bus 95. The memory 92, which stores the constant current element which will be described later _(D 1 ~D ₅₎ each pinch current value _(Ip 1 _{~Ip 5).} The power supply 81 operates according to a command from the determination unit 90.

<Characteristics of constant current diode>
As described above, the constant current element D _m of leakage detection device 100 shown in FIG. 1 is obtained by connecting two constant current diode 11a, and 11b to the anti-series. Hereinafter, the characteristics of the inter-terminal current and the inter-terminal resistance with respect to the inter-terminal voltage of the ideal constant current diode CRD (Current Regulative Diode) will be described with reference to FIG.

The constant current diode CRD is a semiconductor element that can always pass a constant current between terminals even if the voltage value between the terminals between the cathode side terminal and the anode side terminal (hereinafter referred to as the voltage value between terminals) changes. Is. As shown in FIG. 3, when a positive voltage is applied between the cathode side terminal and the anode side terminal and the voltage value between the terminals is increased from zero, the pinch-off voltage is shown by the solid line in FIG. until it reaches a value Vp _m, the current value between the terminals (hereinafter, referred to as inter-terminal current value) rises in proportion to the voltage value between the terminals. Pinch-off voltage Vp _m is a voltage value between terminals current value becomes the pinch-off current value Ip _m explaining later. Non-saturation region an area of up to pinch-off voltage value Vp _m inter-terminal voltage value from zero, that. In the non-saturated region, as shown by the alternate long and short dash line in FIG. 3, the resistance value between terminals is small, and the resistance value RL is constant in magnitude.

As shown by the solid line in FIG. 3, when the voltage value between terminals reaches a certain voltage value, the current value between terminals becomes a constant current value. The current value of the pinch-off current value Ip _m. Further, the inter-terminal voltage value as a pinch-off current value Ip _m that pinch-off voltage value Vp _m.

As shown by the solid line in FIG. 3, the voltage across the terminals between the current value exceeds the pinch-off voltage Vp _m is held constant pinch-off current value Ip _m. This region is called the saturation region. As shown by the alternate long and short dash line in FIG. 3, in the saturation region, the inter-terminal resistance value increases in substantially proportional to the inter-terminal voltage value, so that the inter-terminal current value is pinched off even if the inter-terminal voltage value increases. It is maintained at a current value Ip _m.

Further, when a voltage in the negative direction is applied between the cathode side terminal and the anode side terminal, a large current flows in proportion to the absolute value of the voltage value between the terminals.

As described above, the constant current diode CRD, the positive direction between the inter-terminal voltage is applied terminal current is limited to pinch-off current value Ip _m, the inter-terminal voltage in the reverse direction is applied, current flows in opposite directions Has characteristics. Therefore, in the circuit using an AC power source, to constitute a constant current element which limits the positive and negative directions of the inter-terminal current value to pinch off current value Ip _m, as shown in FIG. 1, the same pinch-off current value Ip _m It is necessary to connect the constant current diode CRD of the above in anti-series. A constant current element in which a constant current diode CRD is connected in anti-series can limit the current value between terminals in both positive and negative directions as shown in FIG.

<Constant current element configuration>
As described above, the limit current value Ip _m of constant current element _{D m} are different, it decreases as the detection unit number N of leak detection units _U 1 ~U ₅ increases _(Ip m> Ip It is configured as _{m + 1).} Therefore pinch off current value _Ip 1 _{~Ip 5} of the constant-current element _D 1 to D ₅ of leak detection units _U 1 ~U _5, as shown in FIG. _{5, Ip 1> Ip 2>} Ip 3> Ip 4> Ip _It becomes smaller in the order of 5. Similarly, pinch-off voltage value _Vp 1 _{~Vp 5 is} smaller in the order of _{Vp 1> Vp 2> Vp 3} > Vp 4> Vp 5.

<Operating principle of leak detection device>
Next, the operating principle of the liquid leakage detection device 100 when a liquid leakage occurs will be described with reference to FIGS. 6 to 8. In the following description, it is assumed that a leak has occurred in _{the leak detection unit U m having the detection unit number N = m.} Until liquid leakage occurs, _{the conductive wires 61 and 62 of the liquid leakage detection units U 1 to} U ₅ are insulated, so a closed circuit is formed between the power supply 81 and the conductive wires 61 and 62. No current is flowing. _{In this case, the voltage value between the start end side terminals 13 and 15 of the liquid leakage detection unit U 1} constituting the start end 71 of the liquid leakage detection unit 70 (hereinafter, referred to as the start end voltage value) is the output voltage value of the power supply 81. It is V0.

As shown in FIG. 6, the leak portion 65 by leakage between the conductive wires 61, 62 of the leak detection unit U _m is formed, the conductive lines 61 and 62 are electrically connected to each other through the leak portion 65 .. Accordingly, the power source 81, leak detection unit _{U 1} constant current element from the leak detection unit _{U m D.} 1 to _{D m} and the conductive wire 61, leakage portion 65, leak detection unit _{U m} from leak detection unit U _{A closed circuit of the connecting wire 12 of 1} and the conductive wire 62 and the power supply 81 is formed, and a current starts to flow in this closed circuit. Current flowing through the closed circuit is limited to the smallest Ip _m among the pinch-off current value _Ip 1 _{~Ip m} of each constant current element _D 1 to D _m of the leak detection unit _U 1 ~U _m. When the resistance value of the leak portion 65 and RW, flows pinch-off current of Ip _m, the voltage drop ΔVW the leak portion 65 is as shown in the following equation (1).

Moreover, it flows pinch-off current Ip _m in leak detection unit _U 1 each constant current element of _{~U m-1 D 1 ~D m} -1. As shown at point P in FIG. 7, the voltage value between the terminals of the _{constant current elements D 1} to D _m-1 at this time is lower than that _{of Vp 1} to Vp _m-1. The constant current elements D _{1 to} D _m-1 operate in an unsaturated region in which the inter-terminal current value and the inter-terminal voltage value are in a proportional relationship. In the non-saturated region, the resistance values of the _{constant current elements D 1} to D _{m-1 are low resistance values RL 1 to RL m-1} having a constant magnitude. Therefore, the voltage drop ΔV1 of the constant current elements D ₁ to D _m-1 of the liquid leakage detection units U _{1 to} U _m-1 is as shown in the following equation (2). Here, N is a detection unit number.

であるから、ＲＨ_ｍは、

となる。 As shown in FIG. 7, the constant current element D _m of leak detection unit U _m are operating in point Q in the saturation region limits the inter-terminal current value to pinch off current value Ip _m. In this saturation region, the resistance value of the constant current element D _m is RH (V) which changes depending on the voltage value between terminals. Since a constant starting voltage of a voltage value V0 is applied to the starting end side terminals 13 and 15 of the liquid leakage detection unit U ₁ by the power supply 81 which is a constant voltage source, the constant current element D of the liquid leakage _{detecting unit U m m} holds the voltage value [Delta] V _m between the terminals (V0-ΔV1-ΔVW) become as the resistance value RH _m varies a current value between the terminals Ip _m.

Therefore, RH _m is

Will be.

As a result, as shown in FIG. 8, the voltage value V0 of the starting voltage, the voltage drop ΔV1 between the leak detection unit _{U 1 ~U m-1,} the inter-terminal voltage value of the leak detection unit _{U m} [Delta] V _m If, divided as voltage drop ΔVW the leakage portion 65, a current value flowing through the closed circuit, a constant Ip _m. Therefore, the current value detected by the current sensor 82 is the case of Ip _m, the leak detection unit U _m including a constant current device D _m can be identified as leakage occurrence point.

<Operation of leak detection device>
Next, the operation of the leak detection device 100 will be described with reference to FIGS. 9 to 15. After the liquid leakage detection operation shown in steps S101 to 104 of FIG. 9, the liquid leakage detection device 100 performs the saturation determination operation of the constant current element shown in steps S105 and S106 of FIG. 9, and the constant current element becomes saturated. If this is the case, the leak detection unit in which the leak has occurred is specified in step S107 of FIG. As described above, leakage detection device 100, leak detection where the constant current element D _m of leak detection unit U _m occurs for leakage based on the pinch-off current value Ip _m when operated in the saturation region It identifies the unit. However, applied current value solution is generated leakage is not to rise suddenly pinch current value Ip _m, rises slowly from zero to the pinch-off current value Ip _m. In this case, the energization current value coming through a smaller _{Ip m + 1, Ip m +} 2 ··· than Ip _m. Therefore, if the leak location is specified without determining saturation, the leak detection units U _{m + 1} and U _{m + 2 on the terminal side of the leak detection unit U m} where the leak actually occurred will be leaked. It may be misidentified as a location. Therefore, the liquid leakage detection device 100 performs a saturation determination operation of the constant current element, determines that it is possible to identify the liquid leakage detection unit in which the liquid leakage has occurred when the constant current element is saturated, and detects the liquid leakage. Performs a specific operation of the unit. The details of each operation will be described below.

As described above, until the leakage occurs, _{the conductive wires 61 and 62 of the leakage detection units U 1 to} U ₅ are insulated from each other, so that a closed circuit is not formed and a current flows. do not have. Therefore, the voltage value between the conductive wires 61 and 62 is V0, which is the output voltage value of the power supply 81. As shown in FIG. 10, the energizing current value detected by the current sensor 82 before the time t1 when the liquid leakage occurs is zero, and the starting voltage value is V0, which is the voltage value of the power supply 81.

As shown in step S101 of FIG. 9, the determination unit 90 detects the electric current value of the leakage detection unit 70 by the current sensor 82, the energization voltage detected proceeds to step S102 in FIG. 9 and the predetermined value Ip _s Judge whether it is above. Here, the predetermined value Ip _s, a threshold determining whether leakage has occurred. If the predetermined value Ip _s is smaller than the pinch-off current value Ip ₅ of the constant current element D _{5 of the liquid leakage detection unit U 5 at} the end (N = 5) where the pinch-off current value is the minimum and larger than zero. well, for example, a predetermined value Ip _s may be a current value of the half of Ip _5. Since no current is flowing at the time zero shown in FIG. 10, the determination unit 90 determines NO in step S102, returns to step S101 in FIG. 9 as no leak detected in step S103 of FIG. 9, and detects the leak. The monitoring of the energizing current value of the unit 70 is continued.

When a liquid leak occurs at time t1 shown in FIG. 10, the leaked liquid permeates into the hygroscopic insulating film of the conductive wires 61 and 62. Thus, conduction between the conductive wires 61, 62 of the leak detection unit U _m, energizing current value of the leak detection unit 70 for detecting the current sensor 82 is increased. Since immersion included only to conductive wires 61, 62 of the leak proceeds slowly at first large conduction resistance, and a very small value flowing current value between the conductive wires 61, 62 of the leak detection unit U _m Become. Therefore, until time t2 in FIG. 10, the energization current value of the leak detection unit 70 for detecting the current sensor 82 does not become larger than a predetermined value Ip _s, determination unit 90 determines NO in step S102 , Steps S101 to S103 of FIG. 9 are repeatedly executed.

From time t1 to t2 in FIG. 10, as the amount of leakage liquid permeating into the conductive wires 61 and 62 increases, the current-carrying resistance between the conductive wires 61 and 62 decreases, and between the conductive wires 61 and 62. The energizing current value gradually increases. When the electric current value detected by the current sensor 82 at time t2 in FIG. 10 reaches a predetermined value Ip _s, the determination unit 90 proceeds to step S104 in FIG. 9 determines YES in step S102 of FIG. 9, Detect leaks. Then, the determination unit 90 proceeds to step S105 in FIG. 9 performs one of the determining operation if the constant current element D _m of leak detection unit U _m is in saturation.

Hereinafter, the determination unit 90 will be described to perform the saturation determination operation of the constant-current element D _m at time t3 in FIG. 10. At time t3 shown in FIG. 10, the resistance value of the leakage portion 65 formed between the leak detection unit U _m of conductive lines 61 and 62 by leakage RW is still very large, calculated by Equation (1) The voltage drop ΔVW of the leaked portion 65 is very large. Therefore, as shown in the voltage distribution of FIG. 12, the constant current element D _m does not reach the terminal voltage of the constant current element D _m is the pinch-off voltage value Ip _m of leak detection unit U _m is a non-saturation state The resistance value is a low resistance value RL _m having a constant magnitude. A constant current element D ₁ ~D _m-1 similarly desaturate small leak detection unit pinch-off voltage value than _{Ip m U 1 ~U m-1} , the resistance value of the constant magnitude lower resistance The values are RL _{1 to RL m-1} .

Therefore, at time t3 shown in FIG. 10, the closed circuit formed by the leaked portion 65 shown in FIG. 11 has the resistance value shown in the following equation (5).

Assuming that the starting voltage value is V0 _{, the current values flowing through the constant current elements D 1 to} D _m and the leaking portion 65 are as shown in the following equation (6).

At this time, the constant current elements D _{1 to} D _m are operating at the point R shown in FIG. 13, and the voltage-current characteristics of the liquid leakage detection unit 70 are shown in the solid line a in FIG. Therefore, when the voltage applied to the liquid leakage detection unit 70 is changed, the energizing current value changes along the solid line a in FIG. That is, when all the constant current elements D _{1 to} D _{m of the liquid leakage detection units U 1 to} U _m are in an unsaturated state, the energizing current value changes when the voltage applied to the liquid leakage detection unit 70 is changed. On the other hand, when the constant current element D _m of any one of the leak detection unit U _m becomes saturated, so the constant current element D _m to limit the energizing current operating point Q shown in FIG. 7 to Ip _m Even if the voltage applied to the liquid leakage detection unit 70 is changed, the energizing current value does not change.

Therefore, when all the constant current elements D _m are in the unsaturated state, as shown in FIG. 14, when the applied voltage is changed by ΔV, the amount of change ΔI of the energizing current value becomes a value of a certain magnitude. On the other hand, when any one of the constant current elements D _m is saturated, as shown in FIG. 15, even if the voltage applied to the liquid leakage detection unit 70 is changed by ΔV, the amount of change ΔI of the energizing current value is It becomes zero.

Therefore, the determination unit 90 changes the output voltage of the power supply 81 to change the voltage applied to the liquid leakage detection unit 70 by ΔV, and detects the energization current value of the liquid leakage detection unit 70 at that time by the current sensor 82. Based on the amount of change ΔI of the energizing current value, it is determined whether or not _{any one of the constant current elements D m is saturated.}

When the absolute value of the change amount ΔI of the energizing current value when the output voltage of the power supply 81 is changed and the voltage applied to the liquid leakage detection unit 70 is changed by ΔV, the determination unit 90 will eventually It is determined that one constant current element D _m is in a saturated state, and if it is equal to or higher than the first threshold value, it is determined that all the constant current elements D _m are in an unsaturated state. The first threshold value may be, for example, as about 5 to 10% of the pinch-off current Ip _m, pinch-off current of the constant current element D ₅ distal of leak detection unit U ₅ to pinch-off current Ip is minimized It may be about 10% of the value Ip _5.

Further, the determination unit 90 calculates the gradient of the voltage-current characteristic of the liquid leakage detection unit 70 = ΔI / ΔV based on the change amount ΔV of the voltage applied to the liquid leakage detection unit 70 and the change amount ΔI of the energization current value. However, when this inclination is less than the second threshold value, it is determined that any one of the constant current elements D _m is in the saturated state, and when it is equal to or more than the second threshold value, all the constant current elements D _m are in the unsaturated state. You may judge.

Further, the determination unit 90 may calculate the reciprocal ΔV / ΔI instead of ΔI / ΔV to determine the saturation of the _{constant current element D m.}

At time t3 in FIG. 10, the voltage-current characteristic of the liquid leakage detection unit 70 is the state of the solid line a shown in FIG. 13, and the energizing current value changes when the voltage applied to the liquid leakage detection unit 70 is changed. Therefore, at the time t3 of FIG. 3, the determination unit 90 determines NO in step S106 of FIG. 9, proceeds to step S109, returns to step S101 of FIG. 9 while determining the leak location, and energizes the current by the current sensor 82. Continue to monitor the value.

As time passes, the amount of the leaked liquid permeating into the conductive wires 61 and 62 increases, and the energization resistance between the conductive wires 61 and 62 decreases. Then, the voltage drop ΔVW of the liquid leakage portion 65 shown in FIG. 12 gradually decreases, and the voltage between terminals ΔVm of the _{constant current element D m gradually increases.} When the inter-terminal voltage ΔVm of the constant current element D _m reaches the pinch-off voltage value Vp _m, constant current element D _m becomes saturated, supply current value is limited to pinch-off current value Ip _m. After the constant current element D _m is saturated, even if the energization resistance between the conductive wires 61 and 62 becomes smaller, the resistance value RH _{m of the constant current element D m} changes and the energization current value is Ip _m. Is held in. Then, after the time t4 in FIG. 10, the state shown in FIGS. 6 to 8 is reached, the constant current element D _m operates at the Q point shown in FIG. 7, and the constant current elements D _{1 to} D _m-1 are shown in FIG. It operates at the point P shown in 7.

Therefore, during the time from t2 to t4 shown in FIG. 10, the determination unit 90 determines NO in step S106 of FIG. 9 and repeatedly executes steps S101, S102, S104 to S106, and S109 of FIG. Then, the determination unit 90 determines YES in step S106 in FIG. 9 at time t4 in FIG. 10, the process proceeds to step S107 of FIG. 9 was determined to be the specific leak detection unit _{U m} generated in leakage , Identify the leak detection unit where the leak has occurred.

In step S107 of FIG. 9, the determination unit 90 compares the respective pinch-off current value _Ip 1 _{~Ip 5} of the constant current element _D 1 to D ₅ are stored in the energizing current value and the memory 92 obtained by the current sensor 82 Then, it is determined whether or not the difference between the energizing current value and one of the pinch-off current values Ip _{1 to Ip 5 is ± ΔIs.} ΔIs is a predetermined range, for example, it may be about 5 to 10% of the pinch-off current Ip _m, constant current element D ₅ of leak detection unit U ₅ distal to the pinch-off current Ip is minimized The pinch-off current value of Ip ₅ may be about 10%.

The determining unit 90 includes a leak detection unit difference is leakage detection unit U _m generates the leakage including pinch-off current value Ip _m in the range of ± .DELTA.Is the energizing current value detected by the current sensor 82 Identify.

The determination unit 90 proceeds to step S108 shown in FIG. 9 and outputs a liquid leakage generation signal and a liquid leakage location signal to the outside via the output interface 94. On a display device (not shown) connected via the output interface 94, a display such as "leakage occurrence, liquid leakage location: detection unit number 3" is displayed. Further, a liquid leakage warning lamp (not shown) connected via the output interface 94 is turned on.

As described above, in the liquid leakage detection device 100 of the embodiment, the liquid leakage detection units U _{1 to} U _{5 including the constant current elements D 1 to} D ₅ having different current limit values are combined with the constant current elements D _{1 to} D ₅ . connected to a plurality series so limited current value decreases as the connection sequence toward the end from the beginning, the limiting current value Ip ₁ ~Ip ₅ energization current value and the constant current element D ₁ to D ₅ detected by the current sensor 82 Since the leak detection unit in which the leak has occurred is identified by comparing the above, it is possible to improve the detection reliability of the leak location with a simple configuration.

<Supplement to the embodiment>
Or the leakage detection device 100 of the embodiment described, as described with reference to FIG. 2, the node constant current element D _m of ND _m is a constant pinch current value Ip _m is the same and facing the anode current diodes 11a, has been described as connected to 11b to anti-series configuration of the constant current element D _m is not limited to this, as shown in FIG. 16 (a), a constant current diode 11a, 11b of the connection direction Figure Contrary to the state shown in 2, the cathodes may be opposed to each other and connected in anti-series. Further, as shown in FIGS. 16 (b) and 16 (c), one constant current diode 11a and one 11b are arranged on each of the two connecting lines 12 in the same direction, and the current when a liquid leak occurs. The two constant current diodes may be in anti-series with respect to the flow of. Further, as shown in FIG. 16D, the constant current diode 11a may be interposed only in one of the connection lines 12. In this case, the power supply 81 may be configured by using a DC constant voltage power supply. Further, instead of using the constant current diodes 11a and 11b, a constant current element circuit 22 in which an electric circuit having a voltage-current characteristic as shown in FIG. 4 is composed of an IC or the like may be used.

In this way, by variously changing the arrangement of the constant current element D _{m of the node N m} according to the liquid to be detected, it is possible to detect the leak according to the liquid to be detected.

Further, in the liquid leakage detection device 100 of the embodiment, it has been described that the constant current element D _m has the same absolute value of the positive current limit value and the absolute value of the negative current limit value. However, as shown in FIG. 17, a constant current element in which the absolute value of the positive current limiting current and the absolute value of the negative current limiting current are different may be used.

In this case, since the energizing current value in the positive direction and the energizing current value in the negative direction are different, electrolytic corrosion may occur in the conductive wires 61 and 62. Therefore, the time for outputting the positive current from the power supply 81 and the time for outputting the current in the negative direction are set to different lengths, and the area of the positive region (shown by the downward-sloping hatching) and the area of the negative region (right) shown in FIG. (Indicated by downward hatching) is the same. As a result, the amount of electric charge in the positive direction and the amount of electric charge in the negative direction of the alternating current conductive wires 61 and 62 output from the power supply 81 become equal, and the occurrence of electrolytic corrosion in the conductive wires 61 and 62 is suppressed. be able to.

Further, as shown in FIG. 19, the current _{limiting value of the constant current element D m} may be arithmetically reduced as the detection unit number N increases according to the connection order from the start end to the end. For example, Ip _{1 to Ip 5 are pinched-off current value Ip m} as the detection unit number N increases by 1, such as 5.0 (mA), 4.5 (mA), 4.0 (mA), and so on. May be reduced by 0.5 mA.

In this case, by setting the error of the current limit value of the constant current element D _m to an absolute value, for example, ± 0.2 (mA), the energization current value detected by the current sensor 82 and the constant current element D _m the predetermined range when liquid leakage by the limit current value to identify the leak detection unit U _m generated, for example, can be defined as an absolute value as ± 0.3 (mA). Therefore, the above-mentioned predetermined range can be made constant by an absolute value in each constant current element D _{1 to} D _5.

Further, as shown in FIG. 20, the current _{limiting value of the constant current element D m} may be geometrically reduced as the detection unit number N increases according to the connection order from the start end to the end. For example, Ip _{1 to Ip 5} are 5.0 (mA), 5.0 × 0.9 = 4.5 (mA), 5.0 × 0.9 ² = 4.05 (mA), and so on. as such, the detection unit number N may be 0.9 times the pinch-off current value Ip _m with increasing 1.

In this case, the relative value of the error limit current value of the constant current element D _m, for example, by setting as a relative value or ratio Ip _m as Ip _m × 4%, electric current value detected by the current sensor 82 and the predetermined range when liquid leakage by limiting current value of the constant current element D _m to identify the leak detection unit U _m generated, for example, be defined as a relative value or proportion as Ip _m × 10% Can be done. Therefore, the above-mentioned predetermined range can be made constant by a relative value or a ratio in each of the constant current elements D _{1 to} D _5.

<Leakage detection device of other embodiments>
Next, the leak detection devices 200, 300, 400, and 500 of other embodiments will be described with reference to FIGS. 21 to 27. The same parts as those of the liquid leakage detection device 100 of the embodiment described above with reference to FIGS. 1 to 15 are designated by the same reference numerals, and the description thereof will be omitted.

The liquid leakage detection device 200 shown in FIG. 21 includes a liquid _{leakage detection unit U m} including a node ND _{m in which a constant current element D m} is arranged between the connection lines 12 on the side of the conductive wire 61, and a liquid leakage detection unit U m on the side of the conductive wire 62. The liquid leakage detection unit 70 is configured by alternately connecting the liquid leakage detection unit U _{m + 1} including the node ND _{m + 1 in which the constant current element D m + 1} is arranged between the connection lines 12 from the start end 71 to the end end 72 in series. It was done.

The liquid leakage detection device 200 of the present embodiment exerts the same effect by the same operation as the liquid leakage detection device 100.

The liquid leakage detection device 300 shown in FIG. 22 is composed of a pair of conductive wires 61 and 62, includes a start-end side leak detection band 66 through which a current flows when a leak comes into contact, and the power supply 81 is a start-end side leak detection band 66. It is connected to the start end 71 of the liquid leakage detection unit 70 via.

When a liquid leak occurs in the region of the start-end side leak detection band 66, the energizing current is the power supply 81, the conductive wire 61 of the start-end side leak detection band 66, the liquid leakage portion 65, and the conductivity of the start-end side leak detection band 66. Since the current flows through the closed circuit of the wire 62 and the power supply 81, the energizing current value detected by the current sensor 82 is not limited to the current limiting _{value of the constant current elements D 1 to} D _5. Therefore, as shown in steps S201 and S202 of FIG. 23, the determination unit 90 is on the starting end 71 side (detection unit number N = 1) where the energizing current value detected by the current sensor 82 is the maximum value of the limiting current value. if it exceeds the leak detection unit pinch current Ip ₁ of the constant current element D ₁ of the U _1, the starting end side leak detection zone 66 identifies the leakage occurrence point. When the energizing current value detected by the current sensor 82 is Ip ₁ or less, the determination unit 90 performs the liquid leakage detection operation shown in steps S101 to S104 of FIG. 23, as described with reference to FIG. After that, the saturation determination operation of the constant current element shown in steps S105 and S106 of FIG. 23 is performed, and when the constant current element is saturated, the leakage detection unit in which the leakage has occurred is specified in step S107 of FIG. Do the action.

The leak detection device 300 of the present embodiment can identify the leak location even when a leak occurs between the leak detection unit 70 and the power supply 81.

The liquid leakage detection device 400 shown in FIG. 24 includes a liquid leakage detection unit 75, a power supply 81, a current sensor 82, and a determination unit 90. The liquid leakage detection unit 75 is composed of a pair of conductive wires 61 and 62, and from the starting end side liquid leakage detection band 66 in which a current flows when a leak comes into contact between the conductive wires 61 and 62 and the pair of conductive wires 61 and 62. Therefore, it is connected between the terminal side leak detection band 67, in which a current flows when a leak comes into contact between the conductive wires 61 and 62, the start end side leak detection band 66, and the terminal side leak detection band 67, and is connected to the terminal side. It is composed of a node ND having a constant current element D that limits the energizing current value of the liquid leakage detection band 67 to the limiting current value. The power supply 81 is connected to the end ends 66a and 66b of the start end side liquid leakage detection band 66 constituting the start end 79 of the liquid leakage detection unit 75. Further, the end 72 of the liquid leakage detection unit 75 is open. The current sensor 82 detects the energizing current value of the liquid leakage detection unit 75. The configuration of the node ND and the constant current element D is the same as that of the node ND _{m and the} constant current element D _{m of the} liquid leakage detection device 100 described with reference to FIG.

In the liquid leakage detection device 400, the constant current element D limits only the energizing current value of the terminal side liquid leakage detection band 67 to the current limit value, so that the determination unit 90 is as shown in steps S201 to S203 of FIG. When the energizing current value detected by the current sensor 82 exceeds the pinch-off current value Ip of the constant current element D, the starting end side liquid leakage detection band 66 is specified as the leakage occurrence location, and the pinch-off current of the constant current element D is specified. When the value is Ip or less, the terminal-side leakage detection band 67 is specified as the leakage occurrence location.

The leak detection device 400 of the present embodiment can identify whether the leak has occurred in the start end side leak detection band 66 or the end side leak detection band 67 with a simple configuration.

The liquid leakage detection device 500 shown in FIG. 26 is a terminal end side of each of the conductive wires 61 and 62, which is the terminal 72 of the liquid leakage detection unit 70 of the liquid leakage detection device 100 described with reference to FIGS. 1 to 15. A terminating resistor 68 is connected between 61e and 62e.

The liquid leakage detection device 500 of the present embodiment has a power supply 81, constant current elements D _{1 to} D _{5 of the liquid leakage detection units U 1 to} U _5, a conductive wire 61, and a terminating resistor 68 even in a state where no liquid leakage has occurred. A closed circuit is formed from the liquid leakage detection unit U ₅ to the connection wire 12 of the liquid leakage detection unit U ₁ , the conductive wire 62, and the power supply 81. A current less than the pinch-off current value Ip _{5 of the constant current element D 5} , which is the minimum pinch-off current value of the liquid leakage detection unit 70, can always flow through this closed circuit.

Therefore, as shown in steps S301 and S302 of FIG. 27, the determination unit 90 can detect the disconnection of the liquid leakage detection unit 70 when the energization current value detected by the current sensor 82 is less than the disconnection detection threshold value. Here, the disconnection detection threshold value may be a value less than the pinch-off current value Ip _{5 of the constant current element D 5} , which is the minimum pinch-off current value, and zero or more, but may be, for example, a value of about 50% of _{Ip 5.} good.

Further, a terminating constant current diode may be connected instead of the terminating resistor 68. At this time, the pinch-off current value of the terminating constant current diode is set to be less than the pinch-off current value Ip _{5 of the constant current element D 5, which is the minimum pinch-off current value of the liquid leakage detection unit 70.}

The liquid leakage detection device 500 of the present embodiment can detect disconnection of the liquid leakage detection unit 70 in addition to the actions and effects of the liquid leakage detection device 100.

11a, 11b constant current diode, 12 connection wire, 13,15 start end side terminal, 14,16 end side terminal, 22 constant current element circuit, 60 leakage detection band, 61,62 conductive line, 61e, 62e, 66a, 66b End, 63 Insulated coated wire, 65 Leakage part, 66 Start side leak detection band, 67 End side leak detection band, 68 End resistance, 70,75 Leakage detection part, 71,76 Start end, 72,77 End , 81 power supply, 82 current sensor, 90 judgment unit, 91 CPU, 92 memory, 93 input interface, 94 output interface, 95 data bus, 100, 200, 300, 400, 500 liquid leakage detector, CRD constant current diode, D , D ₁ -D ₅ , D _m constant current element, Ip _{1 to Ip 5} , I p _m pinch-off current value (current limit value), Ip _s predetermined value, N detection unit number, ND, ND _{1 to ND 5} , ND _m Node, P, Q, R point, RH _m , RW resistance value, RL _{1 to RL m} low resistance value, U _{1 to} U ₅ , U _m leak detection unit, Vp _{1 to Vp 5} , Vp _m pinch-off voltage value.

Claims (15)

It consists of a pair of conductive wires, a leak detection band in which current flows when a leak comes into contact between the conductive wires, and a current limiting current value connected to the leak detection band. A leak detection unit in which a plurality of leak detection units including a node having a constant current element for limiting are connected in series, and a leak detection unit.
A power supply that is connected to the start end of the liquid leakage detection unit and applies a voltage to the liquid leakage detection unit.
A current detection unit that detects the energizing current value of the liquid leakage detection unit, and
A liquid leakage detection device including a determination unit for determining a liquid leakage detection unit in which a liquid has leaked from the energization current value detected by the current detection unit.
The current limit value of each constant current element of each leak detection unit is different.
The determination unit compares the energization current value detected by the current detection unit with the current limit value of the constant current element to identify the leak detection unit in which the leak has occurred.
A leak detection device characterized by. The liquid leakage detection device according to claim 1.
The node of the leak detection unit
A pair of start end terminals and
A pair of terminal terminals to which the pair of conductive wires of the liquid leakage detection band are connected, respectively.
Includes a pair of connecting wires that connect the start-end terminal and the end-end terminal in parallel.
The constant current element is arranged so as to be interposed in either one or both of the connecting lines.
A leak detection device characterized by. The liquid leakage detection device according to claim 1 or 2.
The current limit value of the constant current element of each leak detection unit decreases according to the connection order from the start end to the end connected to the power supply.
A leak detection device characterized by. The liquid leakage detection device according to any one of claims 1 to 3.
When the difference between the energizing current value detected by the current detection unit and the current limit value of the constant current element of the leak detection unit is within a predetermined range, the determination unit is one of the leaks. Identifying the detection unit as the location of the leak,
A leak detection device characterized by. The liquid leakage detection device according to any one of claims 1 to 4.
The determination unit determines that liquid leakage is detected when the energization current value detected by the current detection unit is equal to or greater than a predetermined value.
A leak detection device characterized by. The liquid leakage detection device according to claim 5.
When the determination unit determines that the liquid leakage is detected, the output voltage of the power supply is changed, and the current detection unit detects the amount of change in the energizing current value of the liquid leakage detection unit.
Based on the amount of change, it is determined from the energizing current value whether or not the leak detection unit in which the leak has occurred can be identified.
A leak detection device characterized by. The liquid leakage detection device according to claim 6.
When the absolute value of the change amount is less than a predetermined first threshold value, the determination unit determines that the leak detection unit in which the leak has occurred can be identified from the energizing current value.
A leak detection device characterized by. The liquid leakage detection device according to claim 6.
The determination unit
The slope of the voltage-current characteristic of the liquid leakage detection unit is calculated based on the amount of change in the output voltage of the power supply and the amount of change in the energization current value detected by the current detection unit.
When the inclination is less than a predetermined second threshold value, it is determined that the leak detection unit in which the leak has occurred can be identified from the energizing current value.
A leak detection device characterized by. The liquid leakage detection device according to any one of claims 6 to 8.
The determination unit
When it is determined from the energizing current value detected by the current detection unit that the leak detection unit in which the leak has occurred can be identified,
When the difference between the energizing current value detected by the current detection unit and the current limit value of the constant current element of the leak detection unit is within a predetermined range, the leak detection unit is leaked. Identifying the location of occurrence,
A leak detection device characterized by. The liquid leakage detection device according to claim 3.
The current limit value of the constant current element of the liquid leakage detection unit becomes smaller in arithmetic progression according to the connection order from the start end to the end connected to the power supply.
When the difference between the energizing current value detected by the current detection unit and the current limit value of the constant current element of the leak detection unit is within a predetermined range, the determination unit is one of the leaks. Identifying the detection unit as the location of the leak,
A leak detection device characterized by. The liquid leakage detection device according to claim 3.
The current limit value of the constant current element of the liquid leakage detection unit becomes geometrically smaller according to the connection order from the start end to the end connected to the power supply.
When the difference between the energizing current value detected by the current detection unit and the current limit value of the constant current element of the leak detection unit is within a predetermined range, the determination unit is one of the leaks. Identifying the detection unit as the location of the leak,
A leak detection device characterized by. The liquid leakage detection device according to claim 4 or 5.
The constant current element of the liquid leakage detection unit differs in the positive current limiting value and the negative current limiting value.
The power supply is an AC power supply,
The determination unit equalizes the amount of current-carrying charge in the positive direction and the amount of current-carrying charge in the negative direction of the alternating current output from the power supply.
A leak detection device characterized by. The liquid leakage detection device according to claim 4 or 5.
It is composed of a pair of the conductive wires, and includes a leak detection band on the starting end side through which a current flows when a leak comes into contact between the conductive wires.
The power supply is connected to the start end of the liquid leakage detection unit via the liquid leakage detection band on the start end side.
When the energizing current value detected by the current detection unit is larger than the maximum value of the current limit value of the constant current element of the liquid leakage detection unit, the determination unit causes a liquid leakage in the starting end side liquid leakage detection band. Identifying the location,
A leak detection device characterized by. It consists of a pair of conductive wires, a leakage detection band on the starting end side where a current flows when a leak comes into contact between the conductive wires, and a pair of the conductive wires, and a current flows when the leak contacts between the conductive wires. A constant current that is connected between the flowing end-side leakage detection band, the start-end leakage detection band, and the terminal-side leakage detection band, and limits the energizing current value of the end-side leakage detection band to the limiting current value. A leakage detector including a node having an element,
A power supply that is connected to the leak detection band on the starting end side and applies a voltage to the leak detection unit.
A current detection unit that detects the energizing current value of the liquid leakage detection unit, and
A leak detection device including a determination unit for determining whether a leak has occurred in the start end side leak detection band or the end side leak detection band from the energization current value detected by the current detection unit. hand,
When the energizing current value detected by the current detection unit is larger than the current limit value of the constant current element of the liquid leakage detection unit, the determination unit identifies the start end side leakage detection band as a leakage occurrence location. Then, when the energizing current value detected by the current detection unit is equal to or less than the current limit value of the constant current element of the liquid leakage detection unit, the terminal side leakage detection band shall be specified as the leakage occurrence location.
A leak detection device characterized by. The liquid leakage detection device according to claim 14.
The node of the liquid leakage detection unit is
A pair of start-side terminals to which the pair of conductive wires of the start-end side liquid leakage detection band are connected, respectively.
A pair of terminal terminals to which the pair of conductive wires of the terminal leak detection band are connected, respectively.
Includes a pair of connecting wires that connect the start-end terminal and the end-end terminal in parallel.
The constant current element is arranged so as to be interposed in either one or both of the connecting lines.
A leak detection device characterized by.

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