JP2006071296A - Water flow detection sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a water flow by taking it out as a change of static capacitance for a water equipment such as a toilet bowl which outputs a signal by detecting the water flow and if no signal is continued for a predetermined time outputs the second signal. <P>SOLUTION: A pair of electrodes 2, 3 are provided on the outer periphery of the piping 1 just upstream of the water tank of the toilet bowl. When the toilet bowl is used, the water 4 in the piping 1 flows, so the temperature of the water changes. The dielectric constant of the water 4 in the piping 1 changes, then the frequency of the oscillator circuit 5 changes. The determination circuit 8 determines the flow of the water by sampling the frequency of the oscillation circuit 5 if the absolute value of the difference of the adjoining sampling frequency exceeds a prescribed value, and outputs the signal of contact output etc. The toilet bowl stops the water automatically after being used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a water flow detection sensor that detects a flow of water in a water pipe.

  In the flow of aging and nuclear family, the elderly who live alone can be watched over and can live with peace of mind, and the family who lives separately from the elderly living alone can also control the safety of the elderly. Various systems that can be confirmed automatically have been proposed, and such demands are increasing.

  However, as a sensor used in such a system, for example, a sensor given to a side who is watching over the perception of “monitoring”, as represented by a television camera, is inappropriate.

  Therefore, if a single person living alone is living normally, a water sensor must be installed in the horizontal pipe that is used upstream of the flush toilet in the toilet. An emergency call system has been put into practical use as a safety confirmation system that automatically detects changes in state. This is called the first prior art. (For example, refer nonpatent literature 1.).

  The water sensor used in this emergency call system (first prior art) is a bearing in a pipette in a lower case made of bronze cast with both ends engraved with male threads that match the diameter of the water pipe (13 mm or 20 mm). A small impeller equipped with a rotatable impeller, which detects the rotation of the magnet attached to the impeller with a magnetic sensor and outputs an electric pulse signal (open collector output) with a constant pulse constant for each aperture. It is a flow sensor. And, as described above, the lower case material is made of bronze cast, has the type approval of the Japan Water Works Association, and has durability that can be attached to the direct pressure location of the water supply pipe (see Non-Patent Document 2, for example). .)

  In addition, the temperature of hot water in a water heater such as floor heating is controlled in a pulsed manner, resulting in a temperature difference in time. That is, control temperature fluctuations occur. The relative permittivity of water is sensitive to temperature. For example, the relative permittivity of water at 25 ° C. and 26 ° C. is 78.541 and 78.191, and changes by 0.45% at a temperature difference of 1 ° C. Therefore, using a resin pipe at the part where hot water is taken out from the water heater, measuring the change in the specific induction electric power due to temperature fluctuation as a change in capacitance, and measuring the flow rate and flow rate, A flow rate determination device has been proposed. This is called the second prior art. (For example, refer to Patent Document 1).

  The flow velocity detecting device according to the second prior art includes a first capacitor composed of electrostatic electrodes provided on both surfaces of a dielectric material such as a flat plate, and an electrostatic electrode provided on both surfaces of the dielectric material such as a flat plate. A second capacitor comprising: a capacitance detecting means for detecting the capacitance of the first capacitor and the second capacitor; and a change in the capacitance of the first capacitor and the second capacitor; From the time difference calculating means for calculating the time difference of the capacitance change between the two capacitors and the flow rate calculating means for calculating the flow speed using the time difference calculated by the time difference calculating means and the distance between the first capacitor and the second capacitor. The first capacitor and the second capacitor are arranged at a predetermined interval outside the pipe through which the fluid flows, and detect the flow velocity using temperature fluctuations. .

Further, the flow rate detection device according to the second prior art includes a flow rate detector having a flow rate calculation means for calculating the flow rate by integrating the flow velocity detected by using the temperature fluctuation as described above for a predetermined time. In this flow rate detection device and the flow velocity detection device, the capacitance detection means may be an oscillation circuit including a capacitor.
"Hell seal system-Ai Tasuke", catalog, Aichi Watch Electric Co., Ltd., July 2003 “Aichi Flow Sensor Series”, catalog, Aichi Watch Electric Co., Ltd. 9 Japanese Patent Laying-Open No. 2003-254987 (page 3-5, FIGS. 1 to 3)

  In the safety confirmation system for detecting a health change in a resident, in the first prior art, when installing the flow sensor, it is necessary to cut the water pipe once to perform installation work, and to install the flow sensor in the horizontal pipe. There was a problem that it was necessary to install.

  In the second prior art, the first and second capacitors provided at a distance from each other, two capacitance detecting means for detecting the capacitance of each capacitor, and the capacitance between both capacitors. This requires a time difference calculating means for calculating the time difference of the change and a flow speed or flow rate calculating means for calculating the flow velocity or flow rate, and there is a problem that the configuration and detection algorithm are plural and the cost is high.

  The safety confirmation system can automatically detect a health change in a resident by detecting the flow of water in a water pipe without detecting the flow rate or flow rate. Accordingly, an object of the present invention is to provide a water flow detection sensor that can solve the problems of the prior art.

In the present invention, the capacitance between a pair of electrostatic electrodes arranged outside the pipe is sampled at intervals. When water flows, the temperature of the water in the pipe near the electrode changes, and the capacitance changes according to the water temperature. The main feature is that if the difference between the sampled adjacent values exceeds a certain value, it is judged that water has flowed and an output signal is output.

  The invention according to claim 1 is a pair of electrostatic electrodes disposed outside the pipe and exhibiting a capacitance according to a relative dielectric constant of water in the pipe, and a capacitance between the pair of electrostatic electrodes. A capacitance detection means for sampling at intervals, and a determination means for determining that water has flowed when a difference between adjacent values sampled by the capacitance detection means exceeds a certain value and outputting an output signal. It is the water flow detection sensor characterized by having.

  According to a second aspect of the present invention, in the water flow detection sensor according to the first aspect, the pair of electrostatic electrodes are arranged in an upstream pipe of a water device that automatically stops water after use, like a flush toilet. It is characterized by this.

  According to a third aspect of the present invention, in the water flow detection sensor of the first or second aspect, the second output signal is output when the output signal of the determination means is input and the input signal is not input for a predetermined time or longer. The determination means is provided.

  According to a fourth aspect of the present invention, in the water flow detection sensor according to the first, second, or third aspect, the pair of electrostatic electrodes are arranged to face the outer periphery of the pipe.

  According to a fifth aspect of the present invention, in the flow rate detection sensor according to the first, second, third, or fourth aspect, the electrostatic capacitance detection means is an oscillation circuit including a capacitor composed of a pair of electrostatic electrodes. It is.

  When installing the water flow sensor, it is not necessary to cut the water pipe once and perform the work as in the first prior art, and it is easy to attach a pair of electrostatic electrodes from the outside of the pipe. Easy to install.

  Further, it is not necessary to accurately detect the true value of the capacitance between the electrostatic electrodes, and it is only necessary to know the change in the capacitance, so that it can be produced with a simple configuration at low cost.

  In the present invention, the change of the water temperature in the pipe near the electrostatic electrode due to the flow of water is detected via the relative permittivity of water and it is determined that the water has started to flow. Therefore, if water continues to flow due to some trouble, this may not be detected. In invention of Claim 2, since water stops automatically with the water stop function of water equipment, there is no possibility that it will continue flowing.

  In the invention of claim 3, when the water is not newly used for a certain time or more, the second judging means judges it and outputs an output signal, so that the resident's abnormality is automatically known after a certain time. Can do.

  In the invention of claim 4, the electrostatic electrode can be easily installed and made compact.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described based on the embodiments shown in the drawings.

  FIGS. 1 and 2 show a preferred embodiment of the present invention. A pair of electrostatic electrodes 2 and 3 are attached to the outer periphery of a resin pipe 1 immediately upstream of a water tank of a toilet flush toilet (not shown) by bonding or the like. It is installed. The electrostatic electrodes 2 and 3 constitute a capacitor C having a capacitance determined by the resin pipe 1 and the water 4 in the pipe 1. That is, the capacitor C constitutes a capacitor C having a capacitance between the pair of electrostatic electrodes 2 and 3. Since the relative dielectric constant of the water 4 changes according to the temperature as described above, the capacitance of the capacitor C changes sensitively to the temperature of the water 4.

The oscillation circuit 5 is an oscillation circuit including the capacitor C. As shown in FIG. 3, the oscillation circuit 5 is constituted by a CR oscillation circuit, and two exclusive OR elements 6 and 7 and two resistors R connected in series. ₁ and R ₂ are connected in parallel to each other, and a capacitor C is connected between a connection point of the exclusive OR elements 6 and 7 and a connection point of the resistors R ₁ and R ₂ . One of the inputs of the exclusive OR element 7 is connected to the power supply Vcc, and the other is connected to the output of the exclusive OR element 6 and the capacitor C. The output of the exclusive OR gate 7 are connected to the resistor R ₂ output terminals.

As is well known, the oscillation frequency f of the oscillation circuit 5 is
f = 1 / (2.2CR ₂ )
And changes in inverse proportion to the capacitance of the capacitor C. Since the capacitance of the capacitor C changes according to the temperature of the water in the pipe 1, that is, the relative dielectric constant of water, the change in the water temperature in the pipe can be known from the oscillation frequency of the oscillation circuit 5.

  The determination circuit 8 samples the capacitance between the pair of electrostatic electrodes 2 and 3 at regular time intervals. In this embodiment, the oscillation frequency of the oscillation circuit 5 is sampled and temporarily stored at intervals of 30 seconds. Then, the absolute value of the difference between the oscillation frequency sampled this time and the oscillation frequency sampled last time is calculated, and if the value exceeds a certain value, it is determined that water has flowed and an output signal such as a contact output is output.

  Since the water is temporarily used when the toilet is used, the water in the pipe 1 moves into the water tank, and water of a different temperature flows through the pipe 1 from the upstream underground pipe. A change in the water temperature in the pipe 1 is detected as a change in the capacity of the capacitor C, and the determination circuit 8 determines that water has flowed and outputs an output signal. Thus, it is detected that water has flowed. The flush toilet connected to the pipe 1 automatically stops when predetermined water flows.

  FIG. 2 is a block diagram of the second embodiment of the present invention, which is different from the first embodiment of FIG. 1 only in that a second determination circuit 9 is connected to the subsequent stage of the determination circuit 8. The output signal of the determination means 8 is input to the second determination circuit 9. Then, when the signal from the determination means 8 is not input for a predetermined fixed time, for example, 24 hours or more, the second output signal is output to notify the resident's abnormality. It should be noted that the set value can be changed for 24 hours, which is the fixed time.

  Further, in the second embodiment and the first embodiment, the sampling interval for sampling the oscillation frequency of the oscillation circuit 5 is not limited to 30 seconds described in the first embodiment. You can shorten it. That is, depending on the purpose of the flow detection, if it is desired to detect it within the shortest possible time from the beginning of the flow, the flow may be shortened as much as necessary. On the other hand, if the measurement interval (sampling interval) is too long, the water temperature may return to the original temperature before the next sampling after the water temperature changes. It is preferable to hold down to the extent.

  FIG. 4 is a block diagram of the third embodiment of the present invention, and FIG. 5 is a diagram for explaining the arrangement relationship between the capacitor C and the pipe 1 in the third embodiment. In this embodiment, a resin-made flat dielectric 10 is sandwiched between flat electrostatic electrodes 2 and 3 to constitute a capacitor C. For the dielectric 10, for example, styrene foam can be used. The electric field between the two electrostatic electrodes 2 and 3 is not limited to the inside of the dielectric 10 sandwiched between the two electrodes 2 and 3, but there is also an electric field that wraps around the edges of the electrodes 2 and 3, as shown in FIGS. When the pipe 1 is disposed in the pipe 1, the capacitance of the capacitor C is changed according to the relative dielectric constant of the water in the pipe 1. Therefore, the water temperature of the water 4 can be detected by detecting the capacitance of the capacitor C. Since this is explained in detail in the second prior art, the details are omitted here.

  When water begins to flow through the pipe 1 and the water temperature in the pipe 1 changes, the dielectric constant of the water 4 changes with time, and the oscillation frequency f of the oscillation circuit 5 including the capacitor C changes. The oscillation frequency f is sampled by the determination circuit 8, and when the absolute value of the difference between adjacent sampling values exceeds a certain value, it is determined that water has flowed and an output signal such as a contact output is output. Secondly, the determination circuit 9 outputs a second output signal when a signal from the determination means 8 is not input for a predetermined fixed time, for example, 24 hours or more, and notifies the resident of the abnormality.

  Incidentally, in the first to third embodiments, the oscillation circuit 5 constantly oscillates at an oscillation frequency corresponding to the capacitance of the capacitor C, and instead of sampling the oscillation frequency f by the determination circuit 8, the oscillation circuit 5 May be intermittently oscillated, and the determination circuit 8 may be operated so as to determine the flow of water based on the difference in oscillation frequency.

  In any of the above embodiments, the sampling function by the determination circuit 8 for sampling the oscillation frequency functions as a capacitance detection means. The determination circuit 8 functions as a determination unit, and the second determination circuit 9 functions as a second determination unit.

  The present invention can be used for a safety confirmation device, a health abnormality notification system, a life abnormality monitoring system, and the like.

1 is a block diagram of Embodiment 1 of the present invention. 1 is an electric circuit diagram of an oscillation circuit used in Embodiment 1 of the present invention. The block diagram of Example 2 of this invention. The block diagram of Example 3 of this invention. The figure explaining arrangement | positioning of the capacitor | condenser and piping of Example 3 of this invention.

Explanation of symbols

1 Piping 2, 3 Electrostatic electrode 4 Water 5 Oscillation circuit (capacitance detection means)
C capacitor 8 determination circuit 9 second determination circuit 10 dielectric

Claims (5)

  A pair of electrostatic electrodes arranged outside the pipe and exhibiting a capacitance according to the relative dielectric constant of water in the pipe, and the capacitance between the pair of electrostatic electrodes is sampled at time intervals And a determination unit that determines that water has flowed when a difference between adjacent values sampled by the capacitance detection unit exceeds a certain value and outputs an output signal. Water flow detection sensor.   The water flow detection sensor according to claim 1, wherein the pair of electrostatic electrodes are arranged in an upstream pipe of a water device that automatically stops water after use, like a flush toilet.   3. The apparatus according to claim 1, further comprising a second determination unit configured to input an output signal of the determination unit and to output a second output signal when the input signal is not input for a predetermined time or more. Water flow detection sensor.   4. The water flow detection sensor according to claim 1, wherein the pair of electrostatic electrodes are disposed so as to face the outer periphery of the pipe. 5. The water flow detection sensor according to claim 1, wherein the capacitance detection means is an oscillation circuit including a capacitor composed of a pair of electrostatic electrodes.

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