JP2018200238A - Leakage detector - Google Patents

Abstract

To provide a leakage detector that can be miniaturized while detecting leakage.SOLUTION: A leakage detector includes a leakage detection unit 42. The leakage detection unit 42 includes: a main flow path 45 for guiding a fuel gas decompressed by a pressure regulator toward a downward side; a valve mechanism 46 that is provided on the main flow path 45, and is closed when the flow rate of the fuel gas is less than a set flow rate and is opened when the flow rate is equal or more than the set flow rate; a bypass flow path 47 for bypassing an area from an upstream side to a downstream side of the valve mechanism 46; and a leakage detection sensor 49 that is provided in the bypass flow path 47 to detect minute leakage of the fuel gas in the downstream side. The bypass flow path 47 is extended along the main flow path 45, and allows the fuel gas in an upstream part 47a within the bypass flow path 47 to flow to a downstream part 47b in nearly the same pressure state.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a leak detection apparatus.

  Conventionally, for example, a fuel gas supply system has been proposed in which high pressure gas from an LP gas cylinder is primarily depressurized by an original regulator, and the primary decompressed fuel gas is secondarily depressurized by a master regulator and a slave regulator. In such a system, the parent regulator is provided in the main channel, and the child regulator is provided in the bypass channel that bypasses the parent regulator. In addition, the set pressure is different between the master regulator and the slave regulator, and the fuel gas below the set flow rate flows through the bypass flow path only through the slave regulator, and the fuel gas exceeding the set flow rate is the parent regulator and the slave regulator. It flows through both flow paths through both of the regulators. Further, the bypass channel is provided with a device such as a microcomputer gas meter equipped with a leak detection sensor. In such a fuel gas supply system, when a pipe crack or the like occurs on the downstream side and a slight leak occurs, the minute flow rate flows only through the bypass flow path, and the minute leak is detected based on the signal from the leak detection sensor. It can be detected (see, for example, Patent Documents 1 and 2).

JP-A-3-41300 JP-A-5-296873

  However, in the fuel gas supply systems described in Patent Documents 1 and 2, in addition to the parent-child adjuster, the overall configuration is large, such as a microcomputer gas meter equipped with a leak detection sensor and a pipe connecting them. It becomes difficult to make compact.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a leak detection device capable of achieving compactness while detecting minute leaks. is there.

  The leak detection device according to the present invention includes a main flow path for guiding the fuel gas decompressed by the pressure regulator to the downstream side, and a valve provided on the main flow path when the flow rate of the fuel gas is less than a set flow rate. A valve mechanism that is in a closed state and opens when the flow rate is equal to or greater than the set flow rate; a bypass passage that bypasses from the upstream side to the downstream side of the valve mechanism; and a fuel that is provided in the bypass passage and downstream A leak detection sensor for detecting a slight gas leak, and the bypass flow path extends along the main flow path, and the upstream portion of the fuel gas in the bypass flow path has substantially the same pressure. It is characterized by flowing to the downstream part in the state.

  According to the leak detection device of the present invention, the valve mechanism is configured such that the valve is closed when the flow rate is less than the set flow rate and the valve is opened when the flow rate is equal to or greater than the set flow rate, the bypass flow path, and the leak detection sensor provided in the bypass flow path. Therefore, when the flow rate of the fuel gas decompressed by the pressure regulator is less than the set flow rate, the fuel gas flows only through the bypass flow path. Therefore, even for a minute leak, the fuel gas flows only through the bypass flow path, and the leak detection sensor grasps the minute leak. In addition, since the bypass flow path is provided along the main flow path and the upstream fuel gas is allowed to flow to the downstream portion with substantially the same pressure, the bypass flow path is not installed in the main flow path. It can be a compact structure along. Therefore, it is possible to provide a leakage detection device that can be made compact while performing leakage detection.

  Further, in the leak detection device according to the present invention, the valve mechanism includes: a valve body that is closed by being pressed against the valve seat; and a valve body that is opened by being separated from the valve seat; and the valve body A spring member that generates a force for pressing against the valve seat, and a part of the fuel gas that is connected to the valve body on the downstream side of the valve body and flows in the valve open state of the valve body It is preferable to have a pressure receiving plate.

  According to this leakage detection device, since the valve body is pressed against the valve seat to be in a closed state, and the spring member that generates a force for pressing the valve body against the valve seat, the leakage detection device is less than the set flow rate. The valve body can be closed by the biasing force of the spring member, and the valve body can be opened against the biasing force of the spring member above the set flow rate. Furthermore, since it has a pressure receiving plate that receives a part of the fuel gas flowing in the valve open state of the valve body, when the valve body is in the valve open state and the differential pressure between the upstream side and the downstream side of the valve body becomes small It is possible to prevent the valve body from immediately shifting to the valve closed state.

  Further, in the leak detection device according to the present invention, the valve mechanism is closed when pressed against the valve seat and is opened when separated from the valve seat. A diaphragm that receives pressure from the fuel gas on the upstream side of the body and whose other surface receives pressure from the fuel gas on the downstream side of the valve body, and a spring member that biases the diaphragm to one side, The valve body is closed when pressed against the valve seat when the diaphragm is in a predetermined position, and the diaphragm moves from the predetermined position to the other side against the urging force of the spring member. In this case, it is preferable that the valve is opened away from the valve seat.

  According to this leakage detection device, a diaphragm that receives pressure from the fuel gas on the upstream side and a pressure from the fuel gas on the other side on the other side, a spring member that biases the diaphragm to the one side, and the diaphragm The valve body is closed when the valve is in a predetermined position, and is opened when the diaphragm moves from the predetermined position to the other side against the biasing force of the spring member. For this reason, the valve body can be closed by the biasing force of the spring member below the set flow rate, and the valve body can be opened against the biasing force of the spring member above the set flow rate.

  In the leak detection apparatus according to the present invention, the pressure regulator is integrated with the pressure regulator, and the pressure regulator receives pressure from the atmospheric pressure chamber on the other side and the pressure from the decompression chamber on the one side which is the fuel gas introduction side. A diaphragm that receives the fuel gas, and shuts off the introduction of the fuel gas to the decompression chamber when the diaphragm is in a predetermined position, and introduces the fuel gas into the decompression chamber when the diaphragm moves from the predetermined position to one side. A link mechanism, and the valve mechanism is in a valve-closed state when the diaphragm is in the predetermined position and when the diaphragm is displaced from the predetermined position to one side by less than a predetermined amount, and the diaphragm is It is preferable to have a valve body that is in a valve-open state when displaced from the predetermined position to the one surface side by a predetermined amount or more.

  According to this leakage detection device, the valve is closed when the diaphragm of the pressure regulator is in a predetermined position and when the diaphragm is displaced from the predetermined position to the one surface side by less than a predetermined amount, and the diaphragm is moved from the predetermined position to the one surface side. And a valve element that is in a valve-opened state when displaced by a predetermined amount or more. For this reason, when the displacement of the diaphragm is less than a set flow rate that is less than a predetermined amount on one side, the valve body is closed, and when the displacement of the diaphragm is greater than a set flow rate that is a predetermined amount or more on one side. Will open the valve body. Therefore, the valve mechanism can be appropriately operated using the diaphragm of the pressure regulator.

  ADVANTAGE OF THE INVENTION According to this invention, the leak detection apparatus which can achieve size reduction can be provided, performing a leak detection.

It is a front view of the gas supply system containing the leak detection apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the detail of the leak detection unit shown in FIG. It is an enlarged view which shows the detail of the valve mechanism shown in FIG. 2, (a) has shown the valve closed state, (b) has shown the valve open state. It is a block diagram which shows the valve mechanism which concerns on 2nd Embodiment. It is a block diagram which shows the valve mechanism and secondary regulator which concern on 3rd Embodiment. It is an enlarged view of the valve mechanism shown in FIG.

  Hereinafter, the present invention will be described according to preferred embodiments. Note that the present invention is not limited to the embodiments described below, and can be appropriately changed without departing from the spirit of the present invention. Further, in the embodiment shown below, there are places where illustration and description of a part of the configuration are omitted, but the details of the omitted technology are within the scope that does not conflict with the contents described below. It goes without saying that known or well-known techniques are applied as appropriate.

  FIG. 1 is a front view of a gas supply system including a leak detection device according to a first embodiment of the present invention. As shown in FIG. 1, a gas supply system 1 according to the first embodiment includes a primary regulator (pressure regulator) 10, a secondary regulator (pressure regulator) 20, a connection pipe 30, and a leak detection device. 40.

  The primary adjuster 10 is a former adjuster with a so-called switching function, and includes a switching lever 11 on the front surface. The switching lever 11 is an operation unit for selecting which one of the LP gas cylinders (not shown) connected to the left and right to introduce the fuel gas. In the example shown in FIG. 1, the switching lever 11 is selected so as to introduce fuel gas from an LP gas cylinder connected to the right side. Moreover, the primary regulator 10 is provided with a diaphragm etc. inside, and is configured to perform primary pressure reduction by opening and closing an internal valve body in accordance with the operation of the diaphragm. The primary decompressed fuel gas is supplied to the secondary regulator 20.

  The secondary regulator 20 performs secondary decompression for further decompressing the primary decompressed fuel gas. Similarly to the primary regulator 10, the secondary regulator 20 includes a diaphragm and the like, and performs secondary pressure reduction by opening and closing the internal valve body in accordance with the operation of the diaphragm. The secondary decompressed fuel gas is supplied downstream.

  The connection pipe 30 is a pipe interposed between the secondary regulator 20 and the leak detection device 40. The secondary regulator 20 and the leakage detection device 40 are connected to the connection pipe 30 via the respective connection portions 21 and 41.

  The leak detection device 40 includes a leak detection unit 42 and a calculation display unit 43. FIG. 2 is a cross-sectional view showing details of the leakage detection unit 42 shown in FIG. As shown in FIG. 2, the leak detection unit 42 includes a main flow path 45, a valve mechanism 46, a bypass flow path 47, a multilayer unit 48, and a leak detection sensor 49.

  The main flow path 45 is a flow path that guides the fuel gas decompressed by the primary and secondary regulators 10 and 20 to the downstream consumer side. The valve mechanism 46 is provided on the main flow path 45 and is in the valve closed state when the flow rate of the fuel gas is less than the set flow rate, and is in the valve open state when the flow rate is equal to or higher than the set flow rate.

  The main channel 45 is formed with a first small hole 45a on the upstream side of the valve mechanism 46 and a second small hole 45b on the downstream side, and the bypass channel is connected so as to connect these small holes 45a and 45b. 47 is provided. The bypass channel 47 is a channel extending along the main channel 45. In the first embodiment, since the main channel 45 is linear, the bypass channel 47 is also linearly extended. In particular, a part of the wall portion 45c forming the main flow channel 45 is also used as a wall portion forming the bypass flow channel 47, and the bypass flow channel 47 connects the main flow channel 45 and the wall portion 45c. It is the structure integrated separately.

  In such a bypass flow path 47, a multilayer unit 48 and a leak detection sensor 49 are provided. The multilayer unit 48 is a quadrangular cylindrical member having a plurality of shunt slopes therein. The leak detection sensor 49 is constituted by, for example, an ultrasonic flow rate detection unit, and is transmitted and received by two ultrasonic transmitters / receivers for transmitting and receiving ultrasonic signals in the multilayer unit 48 and two ultrasonic transmitters / receivers. And a measurement board for measuring the flow rate from the propagation time of the ultrasonic signal.

  Here, when a small pipe crack or the like occurs on the downstream side of the leak detection unit 42, a slight leak occurs. Since the flow rate at the time of minute leakage is smaller than the set flow rate of the valve mechanism 46, the fuel gas flows through the bypass flow path 47. The leak detection sensor 49 detects such a minute flow rate.

  As is clear from FIG. 2, the bypass flow path 47 is not provided with an element corresponding to the child adjuster provided in Patent Documents 1 and 2. For this reason, the bypass channel 47 has a structure in which the fuel gas in the upstream portion 47a flows to the downstream portion 47b while maintaining substantially the same pressure. Here, the substantially equal pressure state is a concept that allows pressure loss when passing through the multilayer unit 48, and is a concept that indicates that there is no positive pressure reduction as in the conventional child regulator.

  The calculation display unit 43 shown in FIG. 1 is attached to the outer wall portion of the leakage detection unit 42 (the outer wall portion of the portion corresponding to the bypass flow path 47), and receives the flow signal from the leakage detection sensor 49 and the received flow signal. Based on this, it is determined whether or not a slight leak has occurred. In addition, the calculation display unit 43 also has a function of displaying the fact when it is determined that a slight leak has occurred. Although not shown, when a pressure sensor is provided in the bypass channel 47, the calculation display unit 43 may have other functions such as a function of determining an abnormality in the adjustment pressure.

  FIG. 3 is an enlarged view showing details of the valve mechanism 46 shown in FIG. 2, wherein (a) shows the valve closed state and (b) shows the valve open state. As shown in FIGS. 3A and 3B, the valve mechanism 46 includes a valve body 46a, a coil spring (spring member) 46b, a connecting rod 46c, and a pressure receiving plate 46d.

  The valve body 46a is a member that can move in the extending direction of the main flow path 45. When the valve body 46a is pressed against the valve seat 45d provided in the main flow path 45, the valve body 46a is closed and separated from the valve seat 45d. By doing so, the valve is opened. The coil spring 46b is provided on the downstream side of the valve body 46a and generates an urging force (force toward the upstream side) for pressing the valve body 46a against the valve seat 45d.

  The connecting rod 46c is a rod-shaped member inserted through the coil spring 46b, and has one end connected to the valve body 46a and the other end connected to the pressure receiving plate 46d. The pressure receiving plate 46d is a plate member connected to the valve body 46a via a connecting rod 46c on the downstream side of the valve body 46a. As shown in FIG. 3B, the pressure receiving plate 46d receives a part of the fuel gas flowing when the valve body 46a is in the valve open state.

  Next, operation | movement of the gas supply system 1 containing the leak detection apparatus 40 which concerns on 1st Embodiment is demonstrated. First, the high-pressure fuel gas from the LP gas cylinder is introduced into the primary regulator 10 and subjected to primary pressure reduction in the primary regulator 10. Then, the fuel gas subjected to the primary pressure reduction flows into the secondary regulator 20 and is secondarily decompressed in the secondary regulator 20. Subsequently, the secondary decompressed fuel gas flows into the leak detection device 40 via the connection pipe 30.

  Here, when a relatively large flow rate of fuel gas is used on the consumer side, the flow rate of the fuel gas is equal to or higher than the set flow rate. Thereby, the valve body 46a of the valve mechanism 46 is separated from the valve seat 45d and is in the valve open state. Therefore, the fuel gas flows through both the main flow path 45 and the bypass flow path 47.

  In addition, since a part of the fuel gas flowing through the main flow path 45 is received by the pressure receiving plate 46d, the valve body 46a is opened and the differential pressure between the upstream side and the downstream side of the valve body 46a is reduced. Sometimes, the valve body 46a is prevented from immediately shifting to the valve closed state.

  On the other hand, since the flow rate of the fuel gas with a small flow rate such as a minute leak is less than the set flow rate, the valve body 46a maintains the valve closed state and flows only through the bypass passage 47. Here, the minute leakage accompanying the pipe crack or the like continues as long as the crack or the like continues to exist. For this reason, the leak detection sensor 49 provided in the bypass flow path 47 continues to detect a minute flow rate for a predetermined number of days.

  Therefore, the calculation display unit 43 determines that there is a slight leak when a minute flow rate is detected continuously for a predetermined number of days (for example, 30 days and can be set from 1 to 30 days), and displays a warning. Become.

  In this way, according to the leak detection device 40 according to the first embodiment, the valve mechanism 46 that is closed when the flow rate is lower than the set flow rate and is open when the flow rate is higher than the set flow rate, the bypass flow channel 47, and the bypass flow channel. Since the leak detection sensor 49 provided in 47 is provided, when the flow rate of the fuel gas decompressed by the secondary regulator 20 is less than the set flow rate, the fuel gas flows only through the bypass passage 47. Therefore, even for a slight leak, the fuel gas flows only through the bypass passage 47 and the leak detection sensor 49 grasps the slight leak. In addition, since the bypass channel 47 is provided along the main channel 45 and the fuel gas in the upstream portion 47a is allowed to flow to the downstream portion 47b while maintaining substantially the same pressure, a child regulator is not installed. A compact structure along the main flow path 45 can be obtained. Therefore, it is possible to provide the leakage detection device 40 that can be made compact while performing leakage detection.

  Further, since the valve body 46a is pressed against the valve seat 45d to be in a closed state and the coil spring 46b that generates a force for pressing the valve body 46a against the valve seat 45d is provided. The valve body 46a can be closed by the biasing force of the coil spring 46b, and the valve body 46a can be opened against the biasing force of the coil spring 46b above the set flow rate. Further, since the pressure receiving plate 46d for receiving a part of the fuel gas flowing in the valve body 46a in the valve open state is provided, the valve body 46a is in the valve open state and the differential pressure between the upstream side and the downstream side of the valve body 46a is small. When it becomes, it can prevent that the valve body 46a transfers to a valve closed state immediately.

  Next, a second embodiment of the present invention will be described. The leak detection device according to the second embodiment is the same as that of the first embodiment, but the configuration of the valve mechanism is different from that of the first embodiment. Hereinafter, differences from the first embodiment will be described.

  FIG. 4 is a configuration diagram showing a valve mechanism 46 according to the second embodiment. As shown in FIG. 4, the valve mechanism 46 according to the second embodiment includes a valve body 46a, a connecting rod 46c, a diaphragm 46e, a coil spring (spring member) 46f, a shaft member 46g, and an operating rod 46h. And a pin 46i.

  The valve body 46a is the same as that of the first embodiment, and is closed when pressed against the valve seat 45d formed in the main flow path 45, and is opened when separated from the valve seat 45d. It will be. The connecting rod 46c is a member provided on the downstream side of the valve body 46a, and has one end connected to the valve body 46a and the other end connected to the operating rod 46h.

  Furthermore, in the second embodiment, the main flow path 45 includes a bulging portion 45e that is hollow on the side, and a small hole 45f for flowing fuel gas is formed in the bulging portion 45e. The small hole 45f is formed on the upstream side of the valve body 46a, and the bulging portion 45e is formed to extend downstream from the small hole 45f along the longitudinal direction of the main flow path 45. The diaphragm 46e is a thin film provided with the bulging portion 45e side separated from the downstream side of the valve body 46a in the main flow path 45. Due to such a configuration, one surface of the diaphragm 46e receives pressure from the fuel gas upstream of the valve body 46a through the small hole 45f. On the other hand, the other surface of the diaphragm 46e receives pressure from the fuel gas on the downstream side of the valve body 46a. Therefore, the diaphragm 46e can be displaced laterally according to the difference between the pressure from the fuel gas upstream of the valve body 46a and the pressure from the fuel gas downstream of the valve body 46a.

  The coil spring 46f is a spring member that urges the diaphragm 46e to one side. The shaft member 46g is a member provided through the diaphragm 46e, and is displaced along with the lateral displacement of the diaphragm 46e. In addition, an operating rod 46h is connected to the distal end side (other surface side) of the shaft member 46g. The operating rod 46h is a substantially L-shaped member, and a shaft member 46g is connected to one side of the L shape, and a connecting rod 46c is connected to the other side of the L shape. In addition, the operating rod 46h is provided with a pin 46i at an L-shaped bent portion, and is rotatable about the pin 46i.

  Next, the operation of the leak detection device 40 according to the second embodiment will be described with reference to FIG. First, when a relatively large flow rate of fuel gas is used on the consumer side, the flow rate of the fuel gas is equal to or higher than the set flow rate. As a result, the pressure on the downstream side of the valve body 46a is greatly reduced, and the diaphragm 46e moves to the other side against the urging force of the coil spring 46f. As a result, the shaft member 46g also moves to the other surface side (see arrow A1), and the operating rod 46h rotates around the pin 46i (see arrow A2). Further, the portion of the operating rod 46h connected to the connecting rod 46c is similarly rotated (see arrow A3), and the connecting rod 46c is displaced downstream. As a result, the valve body 46a is also displaced downstream (see arrow A4), and is separated from the valve seat 45d to be in the valve open state. Therefore, the fuel gas flows through both the main flow path 45 and the bypass flow path 47.

  On the other hand, since the flow rate of the fuel gas with a small flow rate at the time of a minute leak is less than the set flow rate, the diaphragm 46e maintains a predetermined position (position shown in FIG. 4) by the urging force of the coil spring 46f. In this case, the valve body 46a remains in the valve closed state, and a small flow rate of fuel gas flows only through the bypass passage 47. Here, since the micro leak accompanying the pipe crack or the like continues as long as the crack or the like continues to exist, the leak detection sensor 49 continues to detect the micro flow rate for a predetermined number of days.

  Therefore, the calculation display unit 43 determines that there is a slight leak when a minute flow rate is detected for a predetermined number of days, and displays a warning.

  In this way, according to the leak detection device 40 according to the second embodiment, it is possible to provide the leak detection device 40 that can be made compact while performing leak detection, as in the first embodiment. it can.

  In addition, according to the second embodiment, the diaphragm 46e that receives pressure from the upstream side fuel gas and the other side that receives pressure from the downstream side fuel gas, and the coil that biases the diaphragm 46e to the one side. When the spring 46f and the diaphragm 46e are in a predetermined position, the valve body 46a is closed, and when the diaphragm 46e moves from the predetermined position to the other side against the urging force of the coil spring 46f, the valve body 46a that is opened is opened. Prepare. Therefore, the valve body 46a can be closed by the biasing force of the coil spring 46f below the set flow rate, and the valve body 46a can be opened against the biasing force of the coil spring 46f above the set flow rate. .

  Next, a third embodiment of the present invention will be described. The leak detection device according to the third embodiment is the same as that of the first embodiment, but the configuration of the valve mechanism and the like are different from those of the first embodiment. Hereinafter, differences from the first embodiment will be described.

  FIG. 5 is a configuration diagram illustrating the valve mechanism 46 and the secondary regulator 20 according to the third embodiment. The leak detection device 40 according to the third embodiment has a structure integrated with at least the secondary regulator 20, and the valve body 46 a of the valve mechanism 46 is in a valve open state in conjunction with the operation of the secondary regulator 20. Or the valve is closed. This will be described in detail below.

  First, in the third embodiment, the secondary regulator 20 includes a decompression chamber D, an atmospheric pressure chamber A, a diaphragm 22, a coil spring 23, a shaft member (link mechanism) 24, and an operating rod (link mechanism) 25. A rotation pin 26, a connecting pin 27, a rod-shaped member 28, and a pressure reducing valve 29.

  The decompression chamber D is a part that temporarily holds the medium-pressure fuel gas introduced from the primary regulator 10. The atmospheric pressure chamber A is a portion where the inside becomes an atmospheric pressure by communicating with the outside. The diaphragm 22 is a substantially circular thin film whose peripheral edge is fixed to the casing B, and separates the decompression chamber D and the atmospheric pressure chamber A in an airtight manner. Further, the diaphragm 22 is urged toward the decompression chamber D side (one surface side) by a coil spring 23.

  The shaft member 24 is a member that extends through the center of the diaphragm 22 in the axial direction, and one end side of the operating rod 25 is attached to the tip of the decompression chamber D side. The operating rod 25 extends to the primary regulator 10 side (vertical direction), and a rotation pin 26 is provided in the vicinity of the end on the primary regulator 10 side. The operating rod 25 is rotatable around the rotation pin 26. The operating rod 25 is provided with a connecting pin 27 adjacent to the rotating pin 26. The connecting pin 27 is connected to the rod-shaped member 28. A pressure reducing valve 29 is connected to the tip of the rod-shaped member 28. The pressure reducing valve 29 is a valve that introduces or shuts off the fuel gas from the primary regulator 10.

  As shown in FIG. 5, when the diaphragm 22 is in a predetermined position, such a secondary regulator 20 contacts the valve seat with the valve seat to close the valve, and shuts off the introduction of fuel gas. Yes. When the fuel gas is used from such a state, the pressure in the decompression chamber D decreases. When the pressure in the decompression chamber D decreases, the diaphragm 22 is displaced to one side by the urging force of the coil spring 23. At this time, the operating rod 25 attached to the tip of the shaft member 24 is also displaced to one side. The operating rod 25 displaces the pressure reducing valve 29 upward by rotating around the rotation pin 26. As a result, the pressure reducing valve 29 is separated from the valve seat and opened, and the fuel gas is introduced into the pressure reducing chamber D.

  Thereafter, when fuel gas is introduced into the decompression chamber D, the pressure in the decompression chamber D increases. Thereby, the diaphragm 22 is displaced to the other surface side against the urging force of the coil spring 23. At this time, the operating rod 25 is also displaced to the other surface side. The actuating rod 25 moves the pressure reducing valve 29 closer to the valve seat by turning about the rotation pin 26 and limits the amount of fuel gas introduced. When the introduction amount is limited, the pressure in the decompression chamber D decreases, and the diaphragm 22 moves again to the one surface side. As a result, the pressure reducing valve 29 moves away from the valve seat and increases the amount of fuel gas introduced. Thereafter, the secondary regulator 20 depressurizes the fuel gas while repeating the above operation.

  In the third embodiment, the valve mechanism 46 includes a lever 46j, a pin 46k, and a shaft 46l. One end of the lever 46j is rotatably connected to the housing B via a pin 46k, and the other end is connected to a rod-shaped shaft 46l. The lever 46j is provided so as to penetrate the shaft member 24 in the vertical direction. Therefore, the lever 46j rotates around the pin 46k according to the operation of the diaphragm 22.

  FIG. 6 is an enlarged view of the valve mechanism 46 shown in FIG. As shown in FIG. 6, a valve seat 45 d is formed at a connection portion between the secondary regulator 20 and the main flow path 45. The valve mechanism 46 includes a valve body 46a, a coil spring 46b, and a flange 46m in addition to the above configuration.

  The valve body 46a is in a valve-closed state by being pressed against the valve seat 45d, and is in a valve-opened state by being separated from the valve seat 45d. The coil spring 46b generates an urging force for pressing the valve body 46a against the valve seat 45d. The flange 46m is provided integrally with the rod-shaped shaft 46l and is an enlarged portion that is partially enlarged in the circumferential direction of the rod. The shaft 46l is configured to penetrate the valve body 46a and the valve seat 45d, and is slidable in the penetration direction. The flange 46m is located between the valve body 46a and the valve seat 45d. For this reason, the flange 46m is movable between the valve body 46a and the valve seat 45d. That is, the flange 46m is movable in the play space PS between the valve body 46a and the valve seat 45d.

  As shown in FIGS. 5 and 6, the decompression chamber D is formed with a small hole 45 a (a small hole on the upstream side of the valve mechanism 46) connected to the bypass flow path 47.

  Such a valve mechanism 46 operates as follows. First, when the fuel gas is not used, the pressure reducing valve 29 is closed and the diaphragm 22 is in a predetermined position. In a state where the diaphragm 22 is in a predetermined position, the valve body 46a is pressed against the valve seat 45d and the valve is closed.

  When fuel gas is used from such a state, the diaphragm 22 is displaced to one side. Thereby, the shaft 46l is also displaced to the one surface side. Here, when the flow rate of the fuel gas is equal to or higher than the set flow rate, the displacement amount to the one surface side of the diaphragm 22 is equal to or greater than a predetermined amount. When the displacement of the predetermined amount or more occurs, the flange 46m provided integrally with the shaft 46l is also greatly displaced to one surface side, and the flange 46m comes into contact with the valve body 46a. That is, the shaft 46l moves the valve body 46a to one side through the flange 46m, and the valve is opened. Therefore, the fuel gas flows through both the main flow path 45 and the bypass flow path 47.

  On the other hand, since the flow rate of the fuel gas with a small flow rate at the time of a minute leak is less than the set flow rate, the displacement amount of the diaphragm 22 becomes less than a predetermined amount. In this case, the moving amount of the flange 46m is within the play space PS, and the flange 46m does not push the valve body 46a. Therefore, the valve body 46a remains in the valve closed state, and the small flow amount of fuel gas flows only through the bypass passage 47. Here, since the micro leak accompanying the pipe crack or the like continues as long as the crack or the like continues to exist, the leak detection sensor 49 continues to detect the micro flow rate for a predetermined number of days.

  Therefore, the calculation display unit 43 determines that there is a slight leak when a minute flow rate is detected for a predetermined number of days, and displays a warning.

  In this way, according to the leak detection device 40 according to the third embodiment, it is possible to provide the leak detection device 40 that can be made compact while performing leak detection, as in the first embodiment. it can.

  Further, according to the third embodiment, when the diaphragm 22 of the secondary regulator 20 is at a predetermined position and when the diaphragm 22 is displaced from the predetermined position to the one surface side by less than a predetermined amount, the valve is closed and the diaphragm 22 is closed. Has a valve body 46a that is in a valve-opened state when it is displaced from the predetermined position to the one surface side by a predetermined amount or more. For this reason, when the displacement of the diaphragm 22 becomes less than a set flow rate that is less than a predetermined amount on one side, the valve body 46a is closed, and the displacement of the diaphragm 22 exceeds the set flow rate that is a predetermined amount or more on one side. In this case, the valve body 46a is opened. Therefore, the valve mechanism 46 can be appropriately operated using the diaphragm 22 of the secondary regulator 20.

  As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above-described embodiments, and may be modified without departing from the spirit of the present invention, and may be appropriately changed within a possible range. These techniques may be combined.

  For example, the leak detection device 40 according to the present embodiment includes an ultrasonic flow sensor in the bypass flow path 47, and the calculation display unit 43 thereby determines a slight leak. Other types of flow sensors such as a flow sensor may be provided in the flow path 47.

  Further, in the present embodiment, the leak detection device 40 determines whether or not the flow rate type micro leak is present, but is not limited thereto, and may determine the pressure type micro leak.

  In addition, the leakage detection device 40 according to the first and second embodiments is connected to the secondary regulator 20 via the connection pipe 30 and is configured separately from the secondary regulator 20, but in particular, Not limited to this, the secondary adjuster 20 may be housed in the same housing B and integrated.

  Furthermore, in the above-described embodiment, the leak detection device 40 has the wall portion 45c of the main flow path 45 also used as the wall portion of the bypass flow path 47, but is not limited thereto. The outer walls may be in contact with each other without using the wall 45c. Furthermore, both may be separated in the proximity state. Specifically, the proximity state means that the distance between them is equal to or less than the sum of the left and right distances between the outer walls of the main flow path 45 and the bypass flow path 47, or either of the main flow path 45 and the bypass flow path 47. The case where it is below the right-and-left distance between one outer walls. This is also because they can be made more compact than before.

  Furthermore, in the said embodiment, the length of the secondary regulator 20 and the leak detection unit 42 is connected to the connection pipe (the downstream side of a secondary regulator) of the conventional secondary regulator and a bypass flow path. The length of the pipe is preferably the same as the length of the pipe through which the bypassed gas returns. Thereby, attachment to existing equipment (conventional equipment) can be facilitated.

1: Gas supply system 10: Primary regulator (pressure regulator)
11: Switching lever 20: Secondary regulator (pressure regulator)
21: Connection part 22: Diaphragm 23: Coil spring 24: Shaft member (link mechanism)
25: Actuation rod (link mechanism)
26: Rotating pin 27: Connecting pin 28: Bar-shaped member 29: Pressure reducing valve 30: Connection pipe 40: Leakage detection device 41: Connection part 42: Leakage detection unit 43: Calculation display part 45: Main flow paths 45a, 45b: Small holes 45c: wall 45d: valve seat 45e: bulging portion 45f: small hole 46: valve mechanism 46a: valve body 46b: coil spring (spring member)
46c: Connection rod 46d: Pressure receiving plate 46e: Diaphragm 46f: Coil spring (spring member)
46g: Shaft member 46h: Actuating rod 46i: Pin 46j: Lever 46k: Pin 46l: Shaft 46m: Flange 47: Bypass passage 47a: Upstream portion 47b: Downstream portion 48: Multilayer unit 49: Leakage detection sensor A: Atmospheric pressure chamber A1 to A4: Arrow B: Housing D: Decompression chamber PS: Space

Claims (4)

A main flow path for guiding the fuel gas decompressed by the pressure regulator downstream;
A valve mechanism that is provided on the main flow path and is in a valve-closed state when the flow rate of the fuel gas is less than a set flow rate and is in a valve-open state when the flow rate is equal to or greater than the set flow rate;
A bypass flow path for bypassing from the upstream side to the downstream side of the valve mechanism;
A leakage detection sensor provided in the bypass flow path for detecting minute leakage of fuel gas on the downstream side,
The bypass flow path extends along the main flow path, and causes the fuel gas in the upstream portion in the bypass flow path to flow to the downstream portion while maintaining substantially the same pressure. The valve mechanism is
A valve body that is closed by being pressed against the valve seat, and is opened by being separated from the valve seat; and
A spring member that generates a force for pressing the valve body against the valve seat;
A pressure receiving plate connected to the valve body on the downstream side of the valve body and receiving a part of the fuel gas flowing in the valve open state of the valve body;
The leak detection device according to claim 1, wherein: The valve mechanism is
A valve body that is closed by being pressed against the valve seat, and is opened by being separated from the valve seat; and
A diaphragm having one surface receiving pressure from the fuel gas upstream of the valve body and the other surface receiving pressure from the fuel gas downstream of the valve body;
A spring member that urges the diaphragm to one side,
The valve body is closed when pressed against the valve seat when the diaphragm is in a predetermined position, and the diaphragm moves from the predetermined position to the other side against the urging force of the spring member. The leak detection device according to claim 1, wherein the valve detection unit is separated from the valve seat and is opened. The leak detection device according to claim 1, wherein the leak detection device is integrated with the pressure regulator.
The pressure regulator is
A diaphragm on which the other surface receives pressure from the atmospheric pressure chamber and one surface receives pressure from the decompression chamber on the fuel gas introduction side;
A link mechanism that shuts off introduction of fuel gas into the decompression chamber when the diaphragm is in a predetermined position, and introduces fuel gas into the decompression chamber when the diaphragm moves from the predetermined position to one surface side; Have
The valve mechanism is
When the diaphragm is in the predetermined position and when the diaphragm is displaced from the predetermined position to the one surface side by less than a predetermined amount, the valve is in a closed state, and the diaphragm is displaced from the predetermined position to the one surface side by a predetermined amount or more. A leak detection device characterized by having a valve body in a valve open state.

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