JPH0221734B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention involves disposing two parallel conductors slightly apart from each other at a water leak detection location, and when water leaks between them, the parallel conductors are The present invention relates to a water leakage detection device that detects water leakage based on changes in line resistance.

[Technical Background of the Invention and Problems Therewith] A conventional water leak detection device mainly has two parallel conductors arranged on the floor with a slight distance from each other. When a water leak occurs and the floor surface is flooded with water to a certain extent (approximately 5 mm), the two parallel conductors are short-circuited by water, and a water leak alarm is issued. Therefore, the floor was already soaked with water when the water leak alarm was issued. Therefore, for example, when waste fluid containing radioactive substances leaks at a nuclear power plant, decontamination work requires many people and time, and there is a risk of exposure to radiation due to decontamination.

Therefore, there has been a need for a water leak detection device that can immediately detect, for example, dripping water before a large amount of water leaks onto the floor surface. However, when such a highly sensitive water leakage detection device is used, there is a drawback that the detection device is activated by noise signals other than water leakage and generates false alarms. In other words, in places with high humidity or where moisture in the air condenses on the surface of a tank or the like and the condensed water drips, it is not possible to distinguish between the condensed water and water leaking from the tank. Nakatsuta. In addition, noise signals from lightning or other equipment may cause a water leak alarm to be issued, which may lead to a loss of reliability of the water leak detection device.

[Summary of the invention]

SUMMARY OF THE INVENTION In view of the above problems, the present invention aims to provide a detection device that detects water leakage by distinguishing it from all other noise signals even when water is leaking drop by drop from cracks in a tank or the like. purpose.

This water leakage detection device arranges two conductors 1 and 2 at a detection location so that the two conductors 1 and 2, which are slightly apart from each other, can be bridged by water leakage, and the electric current between the two conductors 1 and 2 is Water leakage is detected based on changes in resistance. It also includes a counter circuit C that integrates the number of peak changes in the resistance value. At the same time, a timer circuit T1 is provided, which measures the time from one peak change in the resistance value to the next peak change, and only when the time is less than a predetermined time, the counter circuit C is activated. Activate. Furthermore, an alarm circuit F is provided, and a water leakage alarm is issued when the value of the counter circuit C reaches a predetermined value.

Therefore, since this device has a counter circuit C and a timer circuit T1, by determining the operating time of the timer circuit T1 and appropriately determining the count number of the counter circuit C, it is possible to effectively prevent water leakage, condensed water, etc. It is possible to distinguish between false signals caused by That is, focusing on the fact that the pitch interval of dripping caused by condensation is generally larger than the pitch interval of dripping caused by water leakage,
The combination of the timer circuit T1 and the counter circuit C distinguishes between erroneous signals. In addition, the reliability of the water leak detection device can be ensured. Further, the timer circuit T1 and the counter circuit C distinguish water leakage signals from noises from lightning or various devices, and from this point of view as well, the reliability of the water leakage detection device can be ensured.

As a result, water leaks are detected when they are in a dripping state, clearly differentiated from other noise signals, and a warning is issued before the damage caused by the water leak becomes serious, thereby minimizing water leakage damage. It can be detected.

[Embodiments of the invention]

Next, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing one embodiment of this device.
FIG. 2 is an embodiment in which a detection band 4 used as a sensor of this device is attached to a wall surface 3, and FIG. 3 is an enlarged cross-sectional view taken along the line A--A in FIG. 2.

The detection end of this device consists of a flexible detection band 4 as shown in FIGS. 2 and 3, for example. This detection band 4 has two conductors 1 and 2 on the surface of a band-shaped insulating rubber.
(stainless steel wire) slightly apart (e.g. 1 to 8
mm) and are arranged parallel to each other, with the surfaces of the conductors 1 and 2 exposed. Then, the detection band 4 having two parallel lines is horizontally arranged on the wall surface 3 using an adhesive or a fastener, as shown in the figure. Then, one ends of these two parallel conductors 1 and 2 are connected to the terminal COM and the terminal DC (or terminal AC), respectively, as shown in FIG. Thus, water leakage is detected based on the change in electrical resistance between the parallel conductors 1 and 2. That is, when the leakage water 6 drips onto the detection band 4 as shown in FIG. 3, the parallel conductors 1 and 2 are short-circuited, and the electrical resistance between them is significantly reduced. An input signal i based on the decrease in the resistance value is input to the amplifier A1, and its output is input to the second timer circuit T2, timer circuit T1, and counter circuit C, respectively. It should be noted that both timer circuits T1 and T2 have variable resistors R1 and R2, respectively, and the set time can be changed as appropriate by means of the variable resistors. For example, the second timer circuit T2
In this case, the setting time can be changed between 2 seconds and 60 seconds. Further, as an example, in the timer circuit T1, the set time can be changed between 2 seconds and 34 seconds.

This allows each set time to be selected depending on the humidity at the water leakage detection location and the surface temperature of the tank or the like.

Therefore, if the set time of the timer circuit T1 is 34 seconds, the timer circuit T1 resets the counter circuit C when the time between one input signal a1 and the second input signal a1 that is subsequently inputted is 34 seconds or more. It outputs a signal t1. Thereby, the first input signal is not counted. next,
The counter circuit C is a circuit that integrates the number of input signals a1 based on peak changes in electrical resistance value, and is connected to the switch circuit SW. This switch circuit SW is provided with terminals 1 to 9, for example, and an appropriate one is selected from among them.
Then, when the counter number reaches the number of the terminal number, one pulse is output from the terminal. As an example, if terminal number 7 is selected, a signal s is output from the switch circuit SW based on seven input signals, and the alarm circuit F is operated.

In this embodiment, terminal No. 9 of the switch circuit SW is selected, and at the 9th count, the switch circuit SW outputs a signal s, which is input to an alarm circuit F consisting of a flip-flop circuit or the like. Further, in the present embodiment, the set time of the second timer circuit T2 is selected to be 60 seconds, as an example. Therefore, the detection band 4 is submerged and its line resistance decreases continuously until it reaches 60
When the alarm continues for seconds, the signal t2 is input to the alarm circuit F via the switch circuit SW. Then, the output terminal f of the alarm circuit F is reversed to 0 potential (or negative potential), the buzzer relay B is activated, and its contact b is turned on, causing the alarm buzzer to sound. At the same time, the operation of contact b is recorded on a time recorder K, and the operation time and the like are recorded.

[Action of the invention]

Next, the operation of the present invention will be explained.

For the experiment, water droplets were allowed to adhere and fall one by one at intervals of several seconds from the experimental water supply pipe 5 as shown in FIG. Then, the water droplet 6 instantaneously short-circuits the parallel conductors 1 and 2 as shown in FIG. 3, and falls downward. At this time, a change in the resistance value r between the parallel conductors 1 and 2 appears as shown in FIG. As is clear from the change in r in FIG. 4, at the first water droplet N1, the inter-conductor resistance decreases to a peak, and then immediately as the water droplet flows out, the line-to-line resistance value increases. However, the resistance value does not decrease as much as it is in a dry state and becomes about 2MΩ. Then the second
At the time of the first water droplet N2, a peak resistance decrease occurs, and a part of the water droplet flows downward.
However, since the first water droplet remains slightly between the lines, the movement of the second water droplet is similar to that of the first water droplet.
It appears completely different from the first water droplet. As a result, the resistance value may actually decrease over time as shown in FIG. Then, another peak-like change appears at the third water droplet N3. Then,
Each time a water droplet is dropped, a different resistance change curve appears, such as N4 and N5. This change in resistance r
is input to the first amplifier A1 as a signal i. Then, the output a1 appears as shown in the lower graph of FIG. Thus, the amplifier A1 is configured to characteristically capture the peak change in each resistance value. At the same time, in a submerged state where both parallel conductors 1 and 2 are continuously short-circuited, the output is connected at a constant level. FIG. 5 shows a time chart of the present device in a state where water droplets are dripping onto the detection band 4. In this example, each water droplet (N1, N2
etc.), the dripping interval is within 34 seconds, and the number of water droplets is 9.
The alarm circuit F is configured to activate and sound a buzzer when the liquid is dripped. Therefore, since the interval between water droplet N0 and water droplet N1 is 34 seconds or more in FIG.
water droplets are counted. Then, the ninth N2 water drop activates the alarm circuit F, and the alarm buzzer sounds. Next, if no water drops fall for 34 seconds after the ninth drop of N9 has flowed down, the alarm circuit F returns to its original state and stops the alarm buzzer from sounding.
Therefore, according to the present device, water droplets generated at the beginning of water leakage can activate the present detection device and issue an alarm. At the same time, the device does not issue an alarm due to water droplets that have a relatively long dripping interval, such as condensed water dripping from the ceiling or the outer surface of the tank. Furthermore, this alarm device will not issue false alarms due to lightning or noise signals generated when equipment stops driving. This is because, in general, these noise signals do not occur consecutively for a predetermined count (for example, nine) within the set time of the timer circuit T1.

Next, FIG. 6 is a flowchart of the present apparatus when the detection band 4 is continuously short-circuited due to water leakage. That is, it shows the operation during submergence. At the time of flooding, the output signal a1 from the first amplifier A1 is at a constant level as shown in FIG. When this output signal a1 continues for 60 seconds, the output signal t2 of the second timer circuit T2 operates the alarm circuit F via the switch circuit SW. Then, the alarm buzzer sounds.

Then, when the alarm stop switch Er is pressed, the alarm stop relay E turns ON, its contact e switches, and the alarm stops, and the alarm stop relay E
is self-maintained. That is, the output signal t1 of the timer circuit T1 and the signal from the contact e are input to the amplifier A2, and the amplifier A2, which outputs a product signal of both signals, outputs a positive level output and activates the alarm stop relay E. It is. At the same time, alarm relay B
OFF and the buzzer stops. Furthermore, amplifier A
The output from the alarm circuit F is input to the reset terminal of the alarm circuit F, and the level of the output terminal f of the alarm circuit F is inverted.

Next, at time y in FIG. 6, the submergence of the detection zone 4 is treated and the output a1 is set to 0 level. Immediately, the output t2 of the second timer circuit T2 returns to 0 level. At the same time, the output of the timer circuit T1 becomes 0 after 34 seconds. Along with this, amplifier A
The output from 2 becomes 0 level. Then, alarm stop relay E turns OFF, its contact e returns, and
The circuit for alarm relay B is prepared. Therefore, even if the alarm stop switch is left in use, the alarm circuit will automatically reset and issue an alarm in case of water leakage again. That is, in this embodiment, it is possible to prevent an accident in which an alarm is not issued when water leaks again due to forgetting to return the alarm stop switch as in the conventional case. Further, subsequent experiments revealed that by forming the cross-sectional shape of the detection band 4 as shown in FIGS. 7 to 14, each curve of r in FIG. 4 changes more peak-like.

〔Effect of the invention〕

In the device of the present invention, leakage water drips between two conductors 1 and 2 that are spaced apart from each other, and when the water droplets separate from the conductors 1 and 2 and fall, the electric resistance between the two conductors 1 and 2 increases. A counter circuit C is provided which focuses on the peak change in the number of peak changes and integrates the number of peak changes. A timer circuit T1 is provided, whereby the counter circuit C is operated only when the time from one peak change in the resistance value to the next peak change is less than a predetermined time. . Furthermore, an alarm circuit F is provided which issues a water leak alarm when the value of the counter circuit C reaches a predetermined value.

The present invention has the above configuration and has the following effects.

(1) Since this device has a counter circuit C and a timer circuit T1, by appropriately determining the operating time of the timer circuit T1 and appropriately determining the count number of the counter circuit C for activation of the alarm circuit F, It is possible to distinguish between actual water leakage and false signals due to condensed water, etc. That is, by focusing on the fact that the pitch interval between drops of condensed water droplets is generally larger than the pitch interval between drops due to water leakage, the combination of the timer circuit T1 and the counter circuit C is used to distinguish between erroneous signals. This also has the effect of ensuring the reliability of the water leakage detection device.

(2) Furthermore, the timer circuit T1 and the counter circuit C can distinguish between noise signals from lightning or various devices and water leakage signals, so this also has the effect of ensuring the reliability of the water leakage detection device. be. This is because, in general, these noise signals do not occur consecutively for a predetermined count (for example, nine) within the set time of the timer circuit T1.

(3) Therefore, water leakage can be detected when it is in a dripping state in a state that is clearly distinguished from other noise signals, and there is an effect that water leakage damage can be minimized. In other words, a water leakage alarm can be issued before the floor surface is flooded.

(4) Next, the embodiment described in claim 2 provides a second circuit that operates the alarm circuit F when the resistance value between the two conductors 1 and 2 maintains the water leakage resistance value for a predetermined time or more. A timer circuit T2 is provided separately. Therefore, the alarm circuit of the present device can be activated even by continuous water leakage or flooding.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the water leakage detection device of the present invention, Fig. 2 shows an embodiment in which a detection band 4 used at the detection end of the detection device is attached to a wall surface 3, and Fig. 3 shows an embodiment of the water leakage detection device of the present invention. The cross-sectional view taken along the line A-A in FIG. 2, and FIG. 4 show the changes in electrical resistance between the parallel conductors 1 and 2 when water drops are dropped onto the detection band 4 one drop at a time interval of several seconds.
and the output state of the amplifier A1 in Figure 1 at that time, the horizontal axis shows time, the vertical axis shows the resistance value or potential, and Figure 5 is a time chart of this device when water leakage is in a dripping state. , Figure 6 shows water leak detection zone 4.
Figures 7 to 13 are enlarged cross-sectional views showing other embodiments of the detection band 4 used in this device, and Figure 14 is the main part of another experimental example. Enlarged plan view. 1, 2...Conductor, 3...Wall surface, 4...Detection band,
5... Water supply pipe, 6... Water drop, 7... Net groove, C...
Counter circuit, T1...Timer circuit, T2...Second timer circuit, F...Alarm circuit, Er...Alarm stop switch, E...Alarm stop relay, B...Alarm relay, A1, A2...Amplifier , SW... switch circuit, S... rectifier, K... time recorder.

Claims (1)

[Claims] 1. Two conductors 1, 2 slightly spaced apart from each other are arranged at a detection location so that water leakage can bridge the two conductors 1, 2, and the distance between the two conductors 1, 2 is A water leakage detection device that detects water leakage based on a change in electrical resistance value includes a counter circuit C that integrates the number of peak changes in the resistance value, and a counter circuit C that integrates the number of peak changes in the resistance value, and a counter circuit C that integrates the number of peak changes in the resistance value. A timer circuit T1 that operates the counter circuit C only when the time until the current time is less than a predetermined time, and an alarm circuit F that issues a water leakage alarm when the value of the counter circuit C reaches a predetermined number. A water leak detection device featuring: 2. The device according to claim 1, further comprising a second timer circuit T2 that activates the alarm circuit F when the resistance value between the two conductors 1 and 2 maintains the water leakage resistance value for a predetermined time or more. .