High-sensitivity water leak detector, check valve device with high-sensitivity water leak blocking function, high-sensitivity water leak alarm system using check valve with high-sensitivity water leak blocking function, and micro-flow detection method applying Hagen-Poiseuille's Law

Abstract

The present invention provides a leak detection check valve equipped with a sensor that senses the position of a movable element that moves in the same way as the movement of the two valve bodies, a main valve and an auxiliary valve, of a check valve installed in a water pipeline, and a leak alarm system equipped with a signal processing device that receives a signal from the sensor of the leak detection check valve and operates a leak alarm and a leak shut-off check valve, as well as a method for detecting minute flow rates that applies Hagen-Poiseuille's law. [Solution] The high-sensitivity water leak detector of the present invention comprises a main valve that blocks the passage of fluid by moving toward the inlet side of the fluid passage, while allowing the passage of a large amount of liquid by moving toward the outlet side of the fluid passage; a sub-valve that blocks the passage of fluid by moving toward the main valve, while allowing the passage of a small amount of fluid by moving toward the outlet side of the sub-valve fluid passage; a movable element attached to the sub-valve; and a sensor that detects the movement of the movable element and outputs a water leak detection signal. The sub-valve is characterized in that its overall length and diameter are optimized.

Description

Technical Field

[0001] The present invention relates to a highly sensitive water leakage warning system and a micro-flow sensing method using a non-return valve for highly sensitive water leakage cut-off, and more particularly, to a highly sensitive water leakage detector having a structure for detecting the movement of the valve body of a non-return valve provided in a water supply pipe, and a signal processing device that receives a detection signal from the highly sensitive water leakage detector, performs information analysis, and operates a water leakage alarm and a water leakage cut-off non-return valve. The present invention also relates to a micro-flow sensing method applying Hagen-Poiseuille's law.

Background Art

[0002] Water leakage in water supply pipes in apartment buildings or buildings not only causes a large waste of water resources and an increase in the burden of water charges, but also causes damage to buildings, household goods, etc. depending on the degree or location of the water leakage, resulting in great damage to residents. In particular, in apartment buildings such as condominiums, large-scale commercial facilities, hotels, etc., a single water leakage may cause significant damage to many residences and rooms downstairs. In reality, water leakage damage occurs frequently to a considerable extent. Therefore, especially in apartment buildings where damage is likely to spread and communication among residents is not close, and hotels where an unspecified large number of people stay, it is necessary to constantly monitor for water leakage and, when water leakage is detected, immediately issue an alarm to each resident, guest, building manager, etc. to prompt countermeasures and prevent the spread of damage.

[0003] There are two types of causes for water leakage that causes damage to buildings, household goods, etc. The first is minute water leakage or a considerable amount of water leakage that occurs naturally due to aging of water supply pipes, etc. The second is artificial water leakage due to forgetting to turn off a faucet or a failure or operational error of equipment using water. To prevent water leakage damage, these two types of water leakage must be detected and an alarm must be issued.

[0004] Several methods are already known for continuously monitoring water leaks within buildings. For example, a method for detecting leaks by measuring acoustic vibrations transmitted through water pipes has been disclosed (see, for example, Patent Document 1). Another method for detecting leaks using ultrasound has also been disclosed (see, for example, Patent Document 2). However, these methods require large-scale equipment and can only detect leaks of a considerable amount. Furthermore, they cannot address leaks caused by human error, such as forgetting to turn off a faucet.

[0005] Furthermore, a check valve with an opening degree display function has been disclosed, which allows the flow rate to be determined by measuring the distance the valve body moves in proportion to the flow rate of the fluid passing through the check valve using multiple magnetic detectors attached to the valve casing opposite the magnet attached to the check valve. (See, for example, Patent Document 3.)

[0006] Furthermore, a leak detection method is disclosed that involves extracting pulsed signals from a sensor attached to a rotary flow meter, collecting and analyzing this data, and determining the presence or absence of a leak. This invention is intended solely for the detection of naturally occurring minute leaks, and determines the presence or absence of a leak by comparing the allowable flow rate when there is no leak in the water pipe with the flow rate when the water is not in use (see, for example, Patent Document 4). Therefore, it cannot deal with man-made leaks. To address the above issues, the applicants reported a leak alarm system using a check valve for leak detection (Patent Document 5). However, as the target buildings such as apartment complexes and hotels become larger, and as the demand for resource conservation of water and electricity increases, there is a need for the development of a leak alarm system and a micro-flow detection method that can detect and shut off leaks with higher sensitivity. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2002-122502 [Patent Document 2] Japanese Patent Publication No. 2002-131170 [Patent Document 3] Japanese Patent Publication No. 2000-205447 [Patent Document 4] Japanese Patent Publication No. 2002-055019 [Patent Document 5] Patent No. 3650812 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The object of the present invention, in view of the problems of the prior art described above, is to provide a high-sensitivity leak detection check valve equipped with a sensor that sensitively detects the position of a movable element that moves in the same way as the movement of the two valve bodies, the main valve and the auxiliary valve, of a check valve installed in a water pipeline, and a high-sensitivity leak alarm system equipped with a signal processing device that receives signals from the sensor of the high-sensitivity leak detection check valve, analyzes the information, and operates a leak alarm and a leak shut-off check valve, as well as a method for detecting minute flow rates that applies Hagen-Poiseuille's law. [Means for solving the problem]

[0009] To achieve the above objective, the high-sensitivity water leak detector of the present invention is: A casing formed so that a cylindrical fluid passage passes through it, A main valve with a large flow opening area is biased toward the inlet side of the fluid passage by a main valve spring, blocking the passage of fluid when it moves toward the inlet side, while allowing a large amount of liquid to pass through when it moves toward the outlet side of the fluid passage. A sub-valve with a small flow opening area is biased toward the main valve by a sub-valve spring, blocking the passage of fluid when it moves toward the main valve, while allowing a small amount of fluid to pass through when it moves toward the outlet side of the sub-valve fluid passage. A movable element attached to the auxiliary valve, which moves within the fluid passage as the main valve or auxiliary valve moves toward the outlet side, It consists of a sensor provided in the casing so as to be located on the outlet side, which detects the movement of the movable element and outputs a water leak detection signal, The auxiliary valve includes an auxiliary valve seat having a cylindrical hole and an auxiliary valve piston portion having a diameter (D) that is movable within the cylindrical hole of the auxiliary valve seat. The aforementioned auxiliary valve piston portion is made of a self-lubricating resin. The aforementioned sub-valve fluid passage is an eccentric annular gap between the cylindrical hole and the sub-valve piston portion, and is represented by the total length (L0), annular gap width (δ), and eccentric length (ε) of the annular gap flow path when there is no flow. The diameter (D) and the total length (L0) of the annular gap channel when there is no flow are optimized according to the following equation 6, which is derived from Hagen-Poiseuille's equation.

[0010]

number

[0011] The check valve device having a high-sensitivity water leakage blocking function of the present invention is A casing formed so that a cylindrical fluid passage passes through it, A main valve with a large flow opening area is biased toward the inlet side of the fluid passage by a main valve spring, blocking the passage of fluid when it moves toward the inlet side, while allowing a large amount of liquid to pass through when it moves toward the outlet side of the fluid passage. A sub-valve with a small flow opening area is biased toward the main valve by a sub-valve spring, blocking the passage of fluid when it moves toward the main valve, while allowing a small amount of fluid to pass through when it moves toward the outlet side of the sub-valve fluid passage. A movable element attached to the auxiliary valve, which moves within the fluid passage as the main valve or auxiliary valve moves toward the outlet side, A water leak detector comprising a sensor provided in the casing so as to be located on the outlet side, which detects the movement of the movable element and outputs a water leak detection signal, Valve closing mechanism, and A check valve device having a highly sensitive water leakage shut-off function, comprising a controller for controlling the drive of the valve closing mechanism based on a detection signal from the highly sensitive water leakage detector. The sub-valve includes a sub-valve seat having a cylindrical hole and a sub-valve piston portion with a diameter (D) that can move in the cylindrical hole of the sub-valve seat. The sub-valve piston portion is made of a self-lubricating resin. The sub-valve fluid passage is an annular gap with an eccentricity between the cylindrical hole and the sub-valve piston portion, and is represented by the total length (L0), annular gap width (δ), and eccentricity length (ε) of the annular gap flow path when there is no flow. The diameter (D) and the total length (L0) of the annular gap flow path when there is no flow are optimized according to the following formula 6 derived from the Hagen-Poiseuille equation. The valve closing mechanism A plunger that penetrates the flow path through which the fluid passes and at least the outer surface thereof is a magnet, is attached to the sub-valve, is located on the outlet side, and can reciprocate within the fluid passage. A coil provided in the casing corresponding to the plunger and controlled by the controller to generate a magnetic field for the movement of the plunger. By controlling the coil so as to move the plunger to the inlet side of the fluid passage, both the main valve and the sub-valve are driven to block the fluid. [[ID=十七]]

[0012]

Number

[0013] The controller includes a determination unit for determining whether there is a small amount of water leakage or a large amount of water leakage based on the detection signal from the highly sensitive water leakage detector. The determination unit is driven by a drive unit that drives the valve closing mechanism to shut off the fluid based on the determination, It includes a reset unit that stops the drive by the aforementioned drive unit.

[0014] The aforementioned reset unit A button reset unit that forcibly stops the drive of the drive unit by operating the reset button, The system includes a monitoring reset unit that automatically stops the drive unit when it detects the use of the water meter after a long period of non-use.

[0015] A guide rail is provided on the inner surface of the outlet side of the casing to guide the valve closing mechanism so that it moves in a straight line.

[0016] The plunger has a plunger body made of a self-lubricating resin so as to be drum-shaped with a passage through which the fluid passes, and is attached to the auxiliary valve, and the magnet is formed on the outer surface of the plunger body.

[0017] The present invention provides a highly sensitive leak alarm system using a check valve with a highly sensitive leak shutoff function, which can generate an alarm signal in both cases of small leaks occurring naturally due to aging of water pipes, etc., and large leaks caused artificially by forgetting to turn off a faucet, etc., using a leak detection check valve. A casing formed so that a cylindrical fluid passage passes through it, A main valve with a large flow opening area is biased toward the inlet side of the fluid passage by a main valve spring, blocking the passage of fluid when it moves toward the inlet side, while allowing a large amount of liquid to pass through when it moves toward the outlet side of the fluid passage. A sub-valve with a small flow opening area is biased toward the main valve by a sub-valve spring, blocking the passage of fluid when it moves toward the main valve, while allowing a small amount of fluid to pass through when it moves toward the outlet side of the sub-valve fluid passage. A movable element attached to the auxiliary valve, which moves within the fluid passage as the main valve or auxiliary valve moves toward the outlet side, A check valve having a high-sensitivity leak shutoff function, comprising a leak detector comprising a sensor provided in the casing so as to be located on the outlet side and which detects the movement of the movable element and outputs a leak detection signal, a valve closing mechanism, and a controller that controls the drive of the valve closing mechanism based on the detection signal from the high-sensitivity leak detector, and The system consists of a signal processing device that processes the detection signal from the aforementioned high-sensitivity water leak detector to extract a water leak alarm signal. The auxiliary valve includes an auxiliary valve seat having a cylindrical hole and an auxiliary valve piston portion having a diameter (D) that is movable within the cylindrical hole of the auxiliary valve seat. The aforementioned auxiliary valve piston portion is made of a self-lubricating resin. The aforementioned sub-valve fluid passage is an eccentric annular gap between the cylindrical hole and the sub-valve piston portion, and is represented by the total length (L0), annular gap width (δ), and eccentric length (ε) of the annular gap flow path when there is no flow. The diameter (D) and the total length of the annular gap channel in the absence of flow (L0) are optimized according to the following equation 6, which is derived from Hagen-Poiseuille's equation: The valve closing mechanism is A plunger through which the fluid passes, with at least its outer surface being magnetic, attached to the auxiliary valve and located on the outlet side, and capable of reciprocating within the fluid passage, The casing is provided to correspond to the plunger and includes a coil that is controlled by the controller to generate a magnetic field for the movement of the plunger, By controlling the coil to move the plunger toward the inlet side of the fluid passage, both the main valve and the auxiliary valve are driven to shut off the fluid. The signal processing device is characterized by comprising: a first discrimination circuit that detects the width of the pulse signal when it detects the pulse signal, counts up the pulse signal according to the required pulse detection and pulse width conditions for small and large amounts of water leakage set in advance, and can extract a water leakage alarm signal if the predetermined conditions are met; and a second discrimination circuit that can extract an operation signal to close the main on / off valve if the water leakage alarm signal continues for a predetermined time.

[0018]

number

[0019] The aforementioned high-sensitivity water leak detector is composed of a proximity switch that switches when the movable element approaches.

[0020] The system is configured to activate the alarm device based on the aforementioned water leak alarm signal.

[0021] The system includes a control means for controlling the opening and closing of the main on-off valve upstream of the leak detection check valve based on the leak alarm signal.

[0022] The present invention provides a method for sensing minute flow rates that applies Hagen-Poiseuille's law. A method for detecting minute water flow leaks in water pipes, The steps include connecting a high-sensitivity leak detector, including a main valve and an auxiliary valve, to the water pipe, When the leakage flow rate is zero, the auxiliary valve is biased toward the main valve by the auxiliary valve spring, and the movement toward the main valve blocks the passage of fluid; In the event of a leak, the auxiliary valve moves to the outlet side of the auxiliary valve fluid passage, allowing a small amount of fluid to pass through. The small amount of fluid flows into the sub-valve fluid passage, and the force acting on the sub-valve is determined by the amount (H) of the sub-valve's movement toward the outlet side of the sub-valve fluid passage, and the bottom area (πD) of the sub-valve piston portion is determined by the diameter (D) of the sub-valve. 2 The stage at which the differential pressure (Δp) acting on ( / 4) balances out, A step of detecting the amount of movement (H) of the auxiliary valve as the movement of the movable element, which is attached to the auxiliary valve and moves within the fluid passage as the auxiliary valve moves toward the outlet side, This consists of the following steps: determining the leakage flow rate (Q) based on the following equation 6 derived from the aforementioned displacement (H) using Hagen-Poiseuille's law; The aforementioned high-sensitivity water leak detector has a casing formed so that a cylindrical fluid passage passes through it, A main valve with a large flow opening area, which is biased toward the inlet side of the fluid passage by the main valve spring, blocking the passage of fluid when it moves toward the inlet side, while allowing a large amount of liquid to pass through when it moves toward the outlet side of the fluid passage, The aforementioned auxiliary valve, It consists of a sensor provided in the casing so as to be located on the outlet side, which detects the movement of the movable element and outputs a water leak detection signal, The auxiliary valve includes an auxiliary valve seat having a cylindrical hole and an auxiliary valve piston portion having a diameter (D) that is movable within the cylindrical hole of the auxiliary valve seat. The aforementioned auxiliary valve piston portion is made of a self-lubricating resin. The aforementioned sub-valve fluid passage is an eccentric annular gap between the cylindrical hole and the sub-valve piston portion, and is represented by the total length (L0), annular gap width (δ), and eccentric length (ε) of the annular gap flow path when there is no flow. The overall length (L0) of the annular gap flow path and the diameter (D) of the sub-valve piston portion are optimized when there is no flow in the sub-valve fluid passage, and the device is characterized by being able to detect the minute flow rate of the small amount of fluid with high sensitivity based on Hagen-Poiseuille's law.

[0023]

number

[0024] The optimized diameter (D) of the auxiliary valve piston section is 7mm to 10mm. In the absence of the optimized flow described above, the total length of the annular gap channel (L0) is 4 mm to 7 mm.

[0025] Furthermore, the minimum detectable flow rate is 0.5 g / min to 1 g / min.

[0026] The self-lubricating resin is one of the following: POM (polyacetal), MC nylon (monomer cast nylon), PTFE (polytetrafluoroethylene), UPE (ultra-high molecular weight polyethylene), PA (polyamide), PP (polypropylene), or PPS (polyphenylene sulfide). [Effects of the Invention]

[0027] The leak detection check valve used in the leak alarm system according to the present invention consists of two valves, a main valve and an auxiliary valve. The auxiliary valve opens only in response to minute flow rates, while the main valve opens in response to larger flow rates, ensuring the valve body operates with high sensitivity even to minute flow rates. The opening and closing of this valve body can be detected by the movement of a movable element that moves in conjunction with the valve body. The signal processing device compares the valve opening / closing signal sent from the leak detection check valve with a preset leak detection value and issues a leak alarm signal under certain conditions. Therefore, it can issue alarms not only for naturally occurring leaks due to aging water pipes, but also for human-induced leaks such as forgetting to turn off a faucet, equipment malfunctions, or operating errors in water heaters. Furthermore, it can also detect and issue alarms based on the magnitude of the leak. According to the present invention, by applying Hagen-Poiseuille's law to optimize the structure of the auxiliary valve of a leak detection check valve, it is possible to provide a method that can detect even minute leaks with high sensitivity. [Brief explanation of the drawing]

[0028] [Figure 1] This is a cross-sectional view of a leak detection check valve used in a leak alarm system using a leak detection check valve according to the present invention, when there is no fluid flow. [Figure 2] This is a cross-sectional view of a leak detection check valve used in a leak alarm system using a leak detection check valve according to the present invention, when the flow rate is low. [Figure 3] This is a cross-sectional view of a leak detection check valve used in a leak alarm system using a leak detection check valve according to the present invention, when the fluid flow rate is high. [Figure 4] This is a cross-sectional view of another embodiment of a leak detection check valve used in a leak alarm system using a leak detection check valve according to the present invention. [Figure 5] This is a block diagram of a water leak alarm system using a check valve for water leak detection according to the present invention. [Figure 6] This figure shows the signal flow of a water leak alarm system using a water leak detection check valve according to the present invention. [Figure 7] This is a phase diagram of a flow in an annular gap. (a) shows the flow in an annular gap with gap width δ and total length L of the annular gap channel, and (b) shows the case with eccentricity of eccentricity length ε. [Figure 8] This figure shows the theoretical and measured values ​​of displacement and differential pressure against leakage flow rate (g / min). [Modes for carrying out the invention]

[0029] Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. Figure 1 is a cross-sectional view of a leak detection check valve used in a leak alarm system according to the present invention, showing the valve closed and no fluid flowing. This leak detection check valve is characterized by having two valve bodies, a main valve and an auxiliary valve, and by having a movable element that moves in conjunction with the movement of either the main or auxiliary valve body, and a sensor that detects when this movable element moves to a predetermined position. Further details are provided below.

[0030] The leak detection check valve 1 comprises a valve casing 4 that constitutes a cylindrical fluid passage A, a main valve seat 5 detachably provided inside the valve casing 4, a main valve 6 with a large flow opening area that is biased toward the main valve seat 5 toward the inlet 2 side by a main valve spring 7 within the fluid passage A and has a sub-valve seat 8 inside the center, a sub-valve 9 with a small flow opening area that is biased toward the sub-valve seat 8 toward the inlet 2 side by a sub-valve spring 10 within the fluid passage A, a movable element 14 provided in the fluid passage on the outlet side of the main valve 6 or sub-valve 9 and moves in conjunction with the movement of the sub-valve 9 shown in Figure 2 or the main valve 6 toward the outlet 3 side shown in Figure 3, and a sensor 17 provided on the valve casing 4 facing the fluid passage on the outlet 3 side of the fluid passage A to sense when the movable element 14 moves to a predetermined position and enters the sensing area and emit a detection signal. In this embodiment, packings 23, formed in a tubular shape from a material such as hard rubber, are embedded in the main valve 6 and the auxiliary valve 9, respectively, at the portions that contact the main valve seat 5 and the auxiliary valve seat 8. The movable element 14 is also integrally fixed to the auxiliary valve 9. Furthermore, the main valve seat 5 is integrally formed with a retaining frame 5a that holds the main valve 6 and the auxiliary valve 9 inside, and a gap is formed in the retaining frame 5a to secure the flow opening area when the main valve 6 is open.

[0031] In this embodiment, the valve casing 4 consists of an inlet-side casing member 18 connected to the water supply side pipeline B, and an outlet-side casing member 16 connected to the water receiving side pipeline C, which houses the retaining frame 5a and the movable element 14, and has a sensor 17 facing the passage A. The two casing members 16 and 18 are connected to each other by means such as screws. In another configuration, the auxiliary valve spring 10 can also be configured to bias the movable element 14 toward the inlet 2 side toward the outlet side 13 of the retaining frame 5a via the auxiliary valve 9. In this embodiment, the movable element 14 is a disc-shaped component perpendicular to the cylindrical fluid passage A, and is provided with a fluid passage 15. Its material is a metal such as stainless steel, aluminum, or copper alloy. The sensor 17 is a standard proximity switch that switches when the metal movable element 14 approaches and changes impedance, and is embedded in the outlet-side casing member 16. The shape and material of the movable element 14 and the proximity switch that detects it are not limited to this embodiment, and various combinations are possible. It is also possible to embed a magnet on the outer circumference of the movable element 14 and use a reed sensor that switches when the magnet approaches as the sensor 17.

[0032] Figure 5 schematically shows the configuration of a leak alarm system 24 using a leak detection check valve according to the present invention, as shown in a block diagram. Figure 6 shows the signal flow of the leak alarm system 24 using a leak detection check valve. In Figure 5, a signal processing device 30 is provided in combination with the leak detection check valve 29 to process detection signals from a sensor in the leak detection check valve 29. As shown in Figure 6, the signal processing device 30 is configured to include a first discrimination circuit 30a that determines the opening or closing of the main valve or sub-valve of the leak detection check valve based on the detection signal from the sensor 34, determines the duration of the opening or closing of the main valve or sub-valve and extracts leak alarm signals S1a and S1b, and a second discrimination circuit 30b that extracts main valve closing signals S2a and S2b from the discrimination result of 30a.

[0033] Furthermore, this signal processing device 30 is configured to activate the alarm device 31 in response to water leak alarm signals S1a and S1b, and also includes a control means 35 that controls the opening and closing of the main on-off valve 33 upstream of the water leak detection check valve 29 in response to water leak alarm signals S2a and S2b. In addition, the water leak alarm signal is transmitted not only to the alarm device 31, but also to a centralized control room 32 (with a permanent resident) in, for example, an apartment building 25, so that immediate response and action can be taken in response to a water leak.

[0034] As shown in Figure 1, when no fluid is flowing, that is, when the pressure in the water supply pipeline B and the pressure in the water receiving pipeline C are equal, the main valve 6 abuts against the valve seat 5 due to the elastic force of the main valve spring 7 and the auxiliary valve spring 10, and the auxiliary valve 9 abuts against the auxiliary valve seat 8 due to the elastic force of the auxiliary valve spring 10. In the absence of fluid flow, the annular gap width (δ) between the cylindrical hole of the auxiliary valve seat 8 and the auxiliary valve piston portion 9a, as shown in Figure 1, is defined as L0 (hereinafter, L0 will be referred to as the "total length of the annular gap flow path when there is no flow"). In another configuration, the outlet end face 11 of the main valve 6 can abut against the inlet end face 13 of the movable element.

[0035] Then, if there is a slight leak in the receiving pipe C, the pressure inside pipe C gradually decreases, and when the differential pressure between the supply pipe B and the receiving pipe C exceeds the elastic force of the auxiliary valve spring 10, as shown in Figure 2, the auxiliary valve 9 is pushed toward the outlet side, and the fluid passage BA is opened at the auxiliary valve piston part of the auxiliary valve 9, which has a small flow opening area (diameter D), and the fluid flows through the annular gap width δ of the annular gap flow path with a total length L between the cylindrical hole of the auxiliary valve seat 8 and the auxiliary valve 9 (the fluid flow is shown by reference numeral 19 in Figure 2). The total length L of the annular gap flow path where the cylindrical hole of the auxiliary valve seat 8 and the auxiliary valve piston part 9a face each other will be referred to below as the "total length of the annular gap flow path when there is flow". The movable element 14, which is integrated with the auxiliary valve 9, moves towards the outlet side (let this be the distance H), and moves to the sensing area of ​​the sensor 17 (the corresponding position in the longitudinal direction of the water flow passage A).

[0036] When the auxiliary valve 9 opens, water is supplied from the water supply pipeline B to the water receiving pipeline C via the water flow passage A. In the case of a small leak, the differential pressure between pipelines B and C counteracts the elastic force of the auxiliary valve spring 10 in a relatively short time, causing the auxiliary valve 9 to contact the auxiliary valve seat 8 and closing the water flow passage A. This movement of the auxiliary valve is captured by the sensor 17 in the form of a pulse signal of a certain length and received by the first discrimination circuit 30a.

[0037] Here, the pulse signal and pulse signal width are detected. If the aforementioned water leak continues, and the next pulse signal is received within a required reset time set to be longer than the pulse signal width, the counter counts up the number of pulse signals. When the count exceeds a predetermined value, the alarm device 31 issues a small water leak alarm signal S1a (a slight, naturally occurring leak, or a leak caused by human error, such as an incompletely closed faucet). In the second discrimination circuit 30b, if this information continues for a longer period after the alarm, it sends an operation signal S2a to the control means 35 to close the main on-off valve 33 after a predetermined duration. In practice, the central control room 32 or the like recognizes the alarm signal and, once it confirms whether there is an abnormality, sends an operation signal (reset signal) to reset the counter or open the main on-off valve 33.

[0038] Furthermore, if there is a significant leak in the receiving pipe C, the pressure inside pipe C will drop rapidly, and the differential pressure will no longer be resolved by simply opening the auxiliary valve 9. In other words, if the flow rate increases and the pressure difference between the inlet and outlet sides of the auxiliary valve 9 is always greater than the biasing pressure of the auxiliary valve spring 10 that biases the auxiliary valve 9 to the auxiliary valve seat 8, the auxiliary valve 9 will remain open. In this case, when the differential pressure between the supply pipe B and the receiving pipe C exceeds the combined elastic force of the main valve spring 7 and the auxiliary valve spring 10, as shown in Figure 3, the main valve 6 is pushed towards the outlet side, opening the fluid passage A with a large flow opening area (the fluid flow is indicated by reference numeral 20), and the movement of the main valve 6 causes the movable element 14 to move towards the outlet side and move to the sensing area of ​​the sensor 17 (corresponding position in the longitudinal direction of the flow passage A).

[0039] When the main valve 6 opens, water is supplied from the water supply pipeline B to the water receiving pipeline C via the water flow passage A. In the case of a considerably large leak, depending on the extent of the leak, the differential pressure between the two pipelines B and C counteracts the combined elastic force of the main valve spring 7 and the auxiliary valve spring 10, causing the main valve 6 to contact the valve seat 5 and close. This movement of the main valve is captured by the sensor 17 in the form of a pulse signal of a certain length or longer and received by the first discrimination circuit 30a.

[0040] Here, the pulse signal and pulse signal width are detected. If the aforementioned water leak continues, and the next pulse signal is received within a required reset time set to be longer than the pulse signal width, the counter counts up the number of pulse signals. When the count exceeds a predetermined value, the alarm device 31 issues a large water leak alarm signal S1b (for naturally occurring, considerably large water leaks, and man-made water leaks, such as forgetting to turn off a faucet). In the second discrimination circuit 30b, if this information continues for a longer period after the alarm, it sends an operation signal S2b to the control means 35 to close the main on-off valve 33 after a predetermined duration. In practice, the central control room 32 or the like recognizes the alarm signal and, once it confirms whether there is an abnormality, sends an operation signal (reset signal) to reset the counter and open the main on-off valve 33.

[0041] As described above, the leak alarm system using the leak detection check valve of the present invention can emit pulsed signals in response to naturally occurring leaks and man-made leaks. The leak alarm system can emit alarm signals that differentiate between the magnitude of the leak, and in emergency situations, it can automatically prevent leaks by closing the main shut-off valve 33.

[0042] As explained in Figures 2 and 3, in the leak detection check valve 1 of the present invention, which has a main valve 6 and an auxiliary valve 9, the auxiliary valve 9 opens when the flow rate is low, and the main valve 6 opens when the flow rate increases, and in each case, the operation transitions from a pulsed opening and closing motion to a continuous opening motion according to the flow rate. The threshold flow rate for opening and closing the main valve, or the threshold flow rate for transitioning from pulsed opening and closing to continuous opening of the main valve, can be set to a desired value by adjusting the spring constants of the main valve spring 7 and the auxiliary valve spring 10, and the flow opening area of ​​the paths 19 and 20. On the other hand, in order to detect minute flow rates with high sensitivity, it is necessary to consider the flow opening area of ​​the flow path 19 (diameter of the sub-valve piston) D, which is the total length L of the annular gap flow path through which the minute flow rate flows when the sub-valve 9 is open, and the annular gap width δ of the flow path 19.

[0043] Figure 4 is a cross-sectional view showing another embodiment of the leak detection check valve 1, which is a component of the leak alarm system of the present invention, showing the state in which the valve is closed and no fluid is flowing. Only the parts that differ from Figure 1 will be explained. In Figure 1, the movable element 14 is integrally formed with the auxiliary valve 9, so the movable element 14 indirectly receives the elastic force of the auxiliary valve spring 10 via the auxiliary valve 9 and is biased toward the outlet side relative to the valve casing 4. In contrast, in the embodiment of Figure 4, the movable element 14 is detached from the auxiliary valve 9 and is biased toward the inlet side relative to the valve casing 4 by the movable element spring 21.

[0044] The structure of the sub-valve 9 for sensing minute flow rates with high sensitivity and its analysis will be described below with reference to Figure 7, based on the embodiment shown in Figure 1. In the receiving pipe C shown in Figure 1, if there is even a slight leak, the pressure inside pipe C gradually decreases, creating a pressure difference between the supply pipe B and the receiving pipe C. When this pressure difference exceeds the elastic force of the auxiliary valve spring 10, as shown in Figure 2, the auxiliary valve 9 is pushed towards the outlet side, opening the fluid passage A through the small flow opening area of ​​the auxiliary valve piston 9a, and a small flow flows through the annular gap width δ, which is the total length of the annular gap flow path when there is flow, between the cylindrical hole of the auxiliary valve seat 8 and the auxiliary valve piston 9a. The flow of this fluid through the annular gap width δ is shown in Figure 2 by reference numeral 19.

[0045] As shown in Figure 7, when a fluid flows at a slow velocity through a very narrow gap, such as the annular gap width δ, the flow field becomes laminar. This laminar flow through a straight circular pipe is called Hagen-Poiseuille flow, and an exact solution can be obtained from the equation of motion for viscous fluids. The flow velocity distribution and the relationship between flow rate and differential pressure can be theoretically derived from Hagen-Poiseuille flow. As shown in Figure 7, the flow of the annular gap width δ of the auxiliary valve 9, in which the auxiliary valve piston part 9a is inserted into the cylindrical hole of the auxiliary valve seat 8 in Figure 2, can also be approximated as Hagen-Poiseuille flow. The relationship between viscosity μ, annular gap width δ, the total length of the annular gap flow path (length from the entrance to the exit of the annular gap) L, the diameter D of the auxiliary valve piston part 9a (or the inner diameter of the cylindrical hole of the auxiliary valve seat), the flow rate Q, and the differential pressure Δp can be expressed by the following equation 1. Equation 1 takes into account the eccentricity (eccentricity length ε) when the auxiliary valve piston part 9a is inserted into the cylindrical hole of the auxiliary valve seat 8.

[0046]

number

[0047] A differential pressure Δp is generated according to the Hagen-Poiseuil formula for the leakage flow rate Q. Bottom area (πD) of the auxiliary valve piston part 9a 2 The differential pressure Δp acting on (4) exerts a force that moves the auxiliary valve piston part 9a. If the auxiliary valve spring 10 is installed compressed from its natural length, a force equal to the initial compression length λ0 of the spring is applied. If the amount of movement of the movable element 14 is H, and the spring constant of the auxiliary valve spring 10 is kspring, then a force of kspring × (H + λ0) acts on it. The bottom area (πD) of the auxiliary valve piston part 9a with respect to the displacement H. 2 Since it balances with the differential pressure Δp acting on ( / 4), it can be written as shown in equation 2 below. Here, Equation 2 takes into account the downward force Fd, which is the resultant force of gravity and buoyancy of the auxiliary valve, when the leak detection check valve 1 is installed vertically rather than horizontally on the water pipe.

[0048]

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[0049]

number

[0050]

number

[0051]

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[0052]

number

[0053] Based on the characteristic evaluation formula, Equation 6, the characteristics of the auxiliary valve 9 are qualitatively described. 1) Regarding the diameter D of the auxiliary valve piston part 9a For the same flow rate Q, a larger diameter D of the auxiliary valve piston 9a results in a larger displacement H. In other words, increasing the diameter D of the sub-valve piston 9a to increase the amount H of movement of the movable element 14 relative to the flow rate Q improves the detection sensitivity. The diameter D of the auxiliary valve piston portion 9a can be 2 mm to 11 mm. Preferably, it can be 7 mm to 10 mm. 2) Regarding the total length L0 of the annular gap channel when there is no flow. As the displacement H approaches the total length L0 of the annular gap channel in the absence of flow, the flow rate Q becomes infinitely large. In other words, as the flow rate Q increases, the displacement H approaches the total length L0 of the annular gap channel in the initial case with no flow, and as the flow rate Q increases further, the auxiliary valve piston part 9a disengages from the auxiliary valve seat 8. In other words, increasing the total length L0 of the annular gap channel in the absence of flow, so as to increase the amount H of movement of the movable element 14 with respect to the flow rate Q, improves the detection sensitivity. The total length L0 of the annular gap channel in the absence of flow can be 2 mm to 8 mm. Preferably, it can be 4 mm to 7 mm. 3) Regarding the annular gap width δ, The annular gap width δ affects the flow rate Q by its cube in Equation 2. In other words, reducing the annular gap width δ relative to the flow rate Q increases the displacement H and improves detection sensitivity. The annular gap width δ can be 10 μm or more and 40 μm or less. Preferably, it can be 15 μm or more and 30 μm or less. 4) Regarding the spring constant kspring As the spring becomes stronger, the displacement H decreases for the same flow rate Q. In other words, using a weaker spring increases the amount of movement H, improving detection sensitivity. The spring constant kspring can be 0.1 N / mm or less. Preferably, it can be 0.08 or less. 5) Regarding the initial compression length λ0 of the spring For the same spring, if the initial compression length λ0 of the spring is large for the same flow rate Q, the amount of displacement H will be small. In other words, using a spring with a small initial compression length λ0 increases the amount of movement H, improving detection sensitivity.

[0054] Based on the findings from 1) to 5) above and equation 6, the diameter D of the auxiliary valve piston portion 9a of the auxiliary valve 9 was optimized to obtain a diameter D of 7 mm to 10 mm. Furthermore, the total length L0 of the annular gap channel when there is no flow is the total length from the cylindrical hole of the sub-valve seat 8 to the sub-valve piston portion 9a when there is no flow. By optimizing the total length L0 of the annular gap channel when there is no flow, a total length L0 of 4mm to 7mm was obtained. [Examples]

[0055] A sub-valve was fabricated with a sub-valve piston section (made of polyacetal (POM)) having an annular gap width δ: 22 μm and a diameter D: 7 mm, a total length L0 of the annular gap flow path when there is no flow: 5 mm, and a sub-valve spring 10 with a spring constant kspring: 0.05 N / mm. The dependence of its displacement (mm) on the flow rate (g / min) was investigated and compared with the theoretical value in Equation 6.

[0056] Figure 8 shows the dependence of displacement (mm) on flow rate (g / min) and the flow rate on differential pressure. As shown in Figure 8, the experimental data for displacement and differential pressure were in good agreement with Equation 6. Therefore, as shown in Figure 8, it was confirmed that even if the minimum detectable flow rate of minute leakage is 1 g / min or less, minute leakage can be calculated using Equation 6. The minimum detectable flow rate for minute leaks can be between 0.5 g / min and 1 g / min. Based on the above, it was confirmed that even minute leaks can be detected by optimizing the diameter (D) of the auxiliary valve piston and the total length (L0) of the annular gap channel when there is no flow, according to Equation 6 derived from Hagen-Poiseuille's equation.

[0057] As already mentioned, Figure 5 shows a water leak alarm system 24 using the water leak detection check valve of the present invention, and is a diagram assuming water piping in an apartment building. In the apartment building 25, tap water is supplied from the water supply pipe 26 to the individual management area 28 (each unit) via the water meter 27. The water leak detection check valve 29 is installed on the water supply side of the water meter 27, and tap water for each water-using equipment is supplied from the water supply side of the water leak detection check valve 29. The flow rate of tap water within the individual management area 28 is constantly detected by the sensor of the water leak detection check valve 29 as the opening and closing of the main valve or sub-valve, and the signal is sent to the signal processing device 30. The signal processing device 30 analyzes the signal sent from the water leak detection check valve 29, and if it is determined that there is a possibility of a water leak, it activates the alarm device 31 and also sends an alarm to the central control room 32. In this embodiment, the signal processing device 30 is installed in the individual management area, but it can also be installed in the central control room 32. [Industrial applicability]

[0058] The present invention provides a highly sensitive leak detector, a check valve device with a highly sensitive leak blocking function, and a highly sensitive leak alarm system using a check valve with a highly sensitive leak blocking function. This system can issue an alarm and block not only leaks that occur naturally due to aging water pipes, but also leaks caused by human error, such as forgetting to turn off a faucet, equipment malfunctions or operating errors in water heaters, and can also detect and alarm based on the magnitude of the leak. Therefore, this invention is a green-related invention that contributes to the conservation of water resources and, consequently, to the reduction of electricity required for water production. [Explanation of Symbols]

[0059] 1. Check valve for leak detection 4 Valve casing 5 Main valve seat 6. Main valve 7. Main valve spring 8. Adjunctal valves 9. Side valve 9a Sub-valve piston section 10. Auxiliary valve spring 14 Mover 16 Outlet side casing member 17 CM 18 Inlet side casing member 19 Fluid flow 24. Leakage Alarm System 29. Check valve for water leak detection 30 Signal Processing Device 31 Alarm D. Diameter of the auxiliary valve piston section Total length of the annular gap channel when there is no L0 flow L Total length of the annular gap channel when there is flow δ width of the annular gap ε eccentricity length

Claims

1. A casing formed so that a cylindrical fluid passage passes through it, A main valve with a large flow opening area is biased toward the inlet side of the fluid passage by a main valve spring, blocking the passage of fluid when it moves toward the inlet side, while allowing a large amount of liquid to pass through when it moves toward the outlet side of the fluid passage. A sub-valve with a small flow opening area is biased toward the main valve by a sub-valve spring, blocking the passage of fluid when it moves toward the main valve, while allowing a small amount of fluid to pass through when it moves toward the outlet side of the sub-valve fluid passage. A movable element attached to the auxiliary valve, which moves within the fluid passage as the main valve or auxiliary valve moves toward the outlet side, It consists of a sensor provided in the casing so as to be located on the outlet side, which detects the movement of the movable element and outputs a water leak detection signal, The auxiliary valve includes an auxiliary valve seat having a cylindrical hole and an auxiliary valve piston portion having a diameter (D) that is movable within the cylindrical hole of the auxiliary valve seat. The aforementioned auxiliary valve piston portion is made of a self-lubricating resin. The auxiliary valve fluid passage is an eccentric annular gap between the cylindrical hole and the auxiliary valve piston portion, and the total length of the annular gap flow path when there is no flow (L ０ It is expressed in terms of the annular gap width (δ) and eccentricity length (ε), The diameter (D) and the total length (L) of the annular gap channel when there is no flow. ０ The high-sensitivity water leak detector is characterized by being optimized according to the following equation 6, which is derived from Hagen-Poiseuil's formula. [Math 6] (Here, Q: flow rate, δ: annular gap width, μ: viscosity, D: diameter of the auxiliary valve piston, Fd: downward force of the auxiliary valve (resultant force of gravity and buoyancy), kspring: spring constant of the auxiliary valve spring, H: amount of movement of the movable element, λ) ０ : Initial compression length of the spring, L ０ : Represents the total length of the annular gap channel when there is no flow, and ε: Represents the eccentricity length.

2. The diameter (D) of the auxiliary valve piston is 7 mm to 10 mm. The total length (L) of the annular gap channel when there is no flow. ０ ) are 4 mm to 7 mm, The high-sensitivity leak detector according to claim 1, characterized in that the minimum detectable flow rate is 0.5 g / min to 1 g / min.

3. The self-lubricating resin is one of POM (polyacetal), MC nylon (monomer cast nylon), PTFE (polytetrafluoroethylene), UPE (ultra-high molecular weight polyethylene), PTFE (polytetrafluoroethylene), PA (polyamide), PP (polypropylene), and PPS (polyphenylene sulfide), as described in claim 1, making it a highly sensitive water leak detector.

4. A casing formed so that a cylindrical fluid passage passes through it, A main valve with a large flow opening area is biased toward the inlet side of the fluid passage by a main valve spring, blocking the passage of fluid when it moves toward the inlet side, while allowing a large amount of liquid to pass through when it moves toward the outlet side of the fluid passage. A sub-valve with a small flow opening area is biased toward the main valve by a sub-valve spring, blocking the passage of fluid when it moves toward the main valve, while allowing a small amount of fluid to pass through when it moves toward the outlet side of the sub-valve fluid passage. A movable element attached to the auxiliary valve, which moves within the fluid passage as the main valve or auxiliary valve moves toward the outlet side, A water leak detector comprising: a sensor provided in the casing so as to be located on the outlet side, which detects the movement of the movable element and outputs a water leak detection signal; Valve closing mechanism, and A check valve device having a high-sensitivity leak shutoff function, comprising a controller that controls the drive of the valve closing mechanism based on a detection signal from the high-sensitivity leak detector, The auxiliary valve includes an auxiliary valve seat having a cylindrical hole and an auxiliary valve piston portion having a diameter (D) that is movable within the cylindrical hole of the auxiliary valve seat. The aforementioned auxiliary valve piston portion is made of a self-lubricating resin. The auxiliary valve fluid passage is an eccentric annular gap between the cylindrical hole and the auxiliary valve piston portion, and the total length of the annular gap flow path when there is no flow (L ０ It is expressed in terms of the annular gap width (δ) and eccentricity length (ε), The diameter (D) and the total length (L) of the annular gap channel when there is no flow. ０ ) is optimized according to equation 6 below, which is derived from Hagen-Poiseuil's formula, The valve closing mechanism is A plunger through which the fluid passes, with at least its outer surface being magnetic, attached to the auxiliary valve, located on the outlet side, and capable of reciprocating within the fluid passage, The casing is provided to correspond to the plunger and includes a coil that is controlled by the controller to generate a magnetic field for the movement of the plunger, A check valve device having a highly sensitive leak shutoff function, characterized in that both the main valve and the auxiliary valve are driven to shut off the fluid by controlling the coil to move the plunger toward the inlet side of the fluid passage. 【Number 6】 (Here, Q: flow rate, δ: annular gap width, μ: viscosity, D: diameter of the sub-valve piston part, Fd: downward force of the sub-valve (combined force of gravity and buoyancy), kspring: spring constant of the sub-valve spring, H: movement amount of the mover, λ ０ : initial compression length of the spring, L ０ : total length of the annular gap flow path when there is no flow, ε: represents the eccentricity length.)

5. The optimized diameter (D) of the auxiliary valve piston is 7 mm to 10 mm. The total length of the annular gap channel (L) when the optimized flow is absent. ０ ) are 4 mm to 7 mm, The check valve device having a high-sensitivity leak shutoff function according to claim 4, characterized in that the minimum detectable flow rate is 0.5 g / min to 1 g / min.

6. The self-lubricating resin is one of POM (polyacetal), MC nylon (monomer cast nylon), PTFE (polytetrafluoroethylene), UPE (ultra-high molecular weight polyethylene), PTFE (polytetrafluoroethylene), PA (polyamide), PP (polypropylene), and PPS (polyphenylene sulfide), characterized in that the check valve device having a high-sensitivity leak-blocking function according to claim 4.

7. The controller includes a determination unit that determines whether the leak is small or large based on the detection signal from the high-sensitivity leak detector, The determination unit is driven by a drive unit that drives the valve closing mechanism to shut off the fluid based on the determination, The check valve device having a high-sensitivity water leakage shutoff function according to claim 4, further comprising a reset unit for stopping the drive by the drive unit.

8. The aforementioned reset unit A button reset unit that forcibly stops the drive of the drive unit by operating the reset button, The check valve device having a high-sensitivity water leak shutoff function according to claim 4, further comprising a monitoring reset unit that automatically stops the drive unit when it detects the use of a water meter after a long period of non-use.

9. The check valve device having a high-sensitivity leak-blocking function according to claim 4, characterized in that a guide rail for guiding the valve closing mechanism to move linearly is provided on the inner surface of the outlet side of the casing.

10. The check valve device having a high-sensitivity leak-blocking function according to claim 4, characterized in that the plunger has a plunger body attached to the auxiliary valve, which is formed of a self-lubricating resin so as to be drum-shaped with a passage through which the fluid passes, and the magnet is formed on the outer surface of the plunger body.

11. A leak alarm system using a leak detection check valve that can generate an alarm signal in both cases of small leaks that occur naturally due to aging water pipes, etc., and large leaks that occur intentionally due to forgetting to turn off a faucet, etc., A casing formed so that a cylindrical fluid passage passes through it, A main valve with a large flow opening area is biased toward the inlet side of the fluid passage by a main valve spring, blocking the passage of fluid when it moves toward the inlet side, while allowing a large amount of liquid to pass through when it moves toward the outlet side of the fluid passage. A sub-valve with a small flow opening area is biased toward the main valve by a sub-valve spring, blocking the passage of fluid when it moves toward the main valve, while allowing a small amount of fluid to pass through when it moves toward the outlet side of the sub-valve fluid passage. A movable element attached to the auxiliary valve, which moves within the fluid passage as the main valve or auxiliary valve moves toward the outlet side, A check valve having a high-sensitivity leak shutoff function, comprising a leak detector comprising a sensor provided in the casing so as to be located on the outlet side and which detects the movement of the movable element and outputs a leak detection signal, a valve closing mechanism, and a controller that controls the drive of the valve closing mechanism based on the detection signal from the high-sensitivity leak detector, and The system consists of a signal processing device that processes the detection signal from the aforementioned high-sensitivity water leak detector to extract a water leak alarm signal. The auxiliary valve includes an auxiliary valve seat having a cylindrical hole and an auxiliary valve piston portion having a diameter (D) that is movable within the cylindrical hole of the auxiliary valve seat. The aforementioned auxiliary valve piston portion is made of a self-lubricating resin. The auxiliary valve fluid passage is an eccentric annular gap between the cylindrical hole and the auxiliary valve piston portion, and the total length of the annular gap flow path when there is no flow (L ０ It is expressed in terms of the annular gap width (δ) and eccentricity length (ε), The diameter (D) and the total length (L) of the annular gap channel when there is no flow. ０ ) is optimized according to equation 6 below, which is derived from Hagen-Poiseuil's formula, The valve closing mechanism is A plunger through which the fluid passes, with at least its outer surface being magnetic, attached to the auxiliary valve, located on the outlet side, and capable of reciprocating within the fluid passage, The casing is provided to correspond to the plunger and includes a coil that is controlled by the controller to generate a magnetic field for the movement of the plunger, By controlling the coil to move the plunger toward the inlet side of the fluid passage, both the main valve and the auxiliary valve are driven to shut off the fluid. A high-sensitivity leak alarm system using a check valve with a high-sensitivity leak shutoff function, characterized in that the signal processing device includes a first discrimination circuit that detects the width of the pulse signal when it detects the pulse signal, counts up the pulse signal according to the required pulse detection and pulse width conditions for small and large amounts of water leakage set in advance, and can extract a leak alarm signal if the predetermined conditions are met, and a second discrimination circuit that can extract an operation signal to close the main on / off valve if the leak alarm signal continues for a predetermined time. [Math 6] (Here, Q: flow rate, δ: annular gap width, μ: viscosity, D: diameter of the auxiliary valve piston, Fd: downward force of the auxiliary valve (resultant force of gravity and buoyancy), kspring: spring constant of the auxiliary valve spring, H: amount of movement of the movable element, λ) ０ : Initial compression length of the spring, L ０ : Represents the total length of the annular gap channel when there is no flow, and ε: Represents the eccentricity length.

12. The optimized diameter (D) of the auxiliary valve piston is 7 mm to 10 mm. The total length of the annular gap channel (L) when the optimized flow is absent. ０ ) are 4 mm to 7 mm, A high-sensitivity leak alarm system using a check valve with a high-sensitivity leak shutoff function according to claim 11, characterized in that the minimum detectable flow rate is 0.5 g / min to 1 g / min.

13. The self-lubricating resin is one of POM (polyacetal), MC nylon (monomer cast nylon), PTFE (polytetrafluoroethylene), UPE (ultra-high molecular weight polyethylene), PTFE (polytetrafluoroethylene), PA (polyamide), PP (polypropylene), and PPS (polyphenylene sulfide), and is characterized by using a check valve having a high-sensitivity leak shutoff function as described in 11.

14. The high-sensitivity water leak alarm system using a check valve with a water leak shutoff function according to claim 11, characterized in that the high-sensitivity water leak detector is configured with a proximity switch that switches when the movable element approaches.

15. The high-sensitivity water leak alarm system using a check valve having a water leak blocking function, as described in 11, is characterized in that the alarm device is activated by the water leak alarm signal.

16. A high-sensitivity leak alarm system using a check valve with a leak shutoff function according to claim 11, characterized in that it includes a control means for controlling the opening and closing of a main on-off valve upstream of the leak detection check valve based on the leak alarm signal.

17. A method for detecting minute water flow leaks in water pipes, The steps include connecting a high-sensitivity leak detector, including a main valve and an auxiliary valve, to the water pipe, When the leakage flow rate is zero, the auxiliary valve is biased toward the main valve by the auxiliary valve spring, and the movement toward the main valve blocks the passage of fluid; In the event of a leak, the auxiliary valve moves to the outlet side of the auxiliary valve fluid passage, allowing a small amount of fluid to pass through. The small amount of fluid flows into the sub-valve fluid passage, and the force acting on the sub-valve is determined by the amount of movement (H) of the sub-valve toward the outlet side of the sub-valve fluid passage, and the bottom area (πD) of the sub-valve piston portion is determined by the diameter (D) of the sub-valve. ２ The differential pressure (Δp) acting in / 4) is at the stage where it balances out, A step of detecting the amount of movement (H) of the auxiliary valve as the movement of the movable element, which is attached to the auxiliary valve and moves within the fluid passage as the auxiliary valve moves toward the outlet side, This consists of the steps of: determining the leakage flow rate (Q) based on the following equation 6 derived from Hagen-Poiseuille's law using the aforementioned displacement (H); The aforementioned high-sensitivity water leak detector has a casing formed so that a cylindrical fluid passage passes through it, A main valve with a large flow opening area, which is biased toward the inlet side of the fluid passage by the main valve spring, blocking the passage of fluid when it moves toward the inlet side, while allowing a large amount of liquid to pass through when it moves toward the outlet side of the fluid passage, The aforementioned auxiliary valve, It consists of a sensor provided in the casing so as to be located on the outlet side, which detects the movement of the movable element and outputs a water leak detection signal, The auxiliary valve includes an auxiliary valve seat having a cylindrical hole and an auxiliary valve piston portion having a diameter (D) that is movable within the cylindrical hole of the auxiliary valve seat. The aforementioned auxiliary valve piston portion is made of a self-lubricating resin. The auxiliary valve fluid passage is an eccentric annular gap between the cylindrical hole and the auxiliary valve piston portion, and the total length of the annular gap flow path when there is no flow (L ０ It is expressed in terms of the annular gap width (δ) and eccentricity length (ε), The total length (L) of the annular gap flow path when there is no flow in the sub-valve fluid passage. ０ A method for sensing minute flow rates that applies Hagen-Poiseuille's law, characterized in that the diameter (D) of the auxiliary valve piston portion is optimized, and the minute flow rate, which is the passage of a small amount of fluid, can be detected with high sensitivity based on Hagen-Poiseuille's law. [Math 6] (Here, Q: flow rate, δ: annular gap width, μ: viscosity, D: diameter of the auxiliary valve piston, Fd: downward force of the auxiliary valve (resultant force of gravity and buoyancy), kspring: spring constant of the auxiliary valve spring, H: amount of movement of the movable element, λ) ０ : Initial compression length of the spring, L ０ : Represents the total length of the annular gap channel when there is no flow, and ε: Represents the eccentricity length.

18. The optimized diameter (D) of the auxiliary valve piston is 7 mm to 10 mm. The total length (L) of the annular gap channel in the case of no flow after optimization ０ ) are 4 mm to 7 mm, A method for sensing minute flow rates that applies Hagen-Poiseuille's law, as described in claim 17, characterized in that the minimum detectable flow rate is 0.5 g / min to 1 g / min.

19. The self-lubricating resin is one of POM (polyacetal), MC nylon (monomer cast nylon), PTFE (polytetrafluoroethylene), UPE (ultra-high molecular weight polyethylene), PTFE (polytetrafluoroethylene), PA (polyamide), PP (polypropylene), and PPS (polyphenylene sulfide), as described in 17, a method for sensing a minute flow rate that applies Hagen-Poiseuille's law.

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