JP6629149B2 - Gas meter flow measurement section - Google Patents

Description

  The present invention relates to a flow meter of a gas meter.

  Gas meters are used to measure gas consumption for each consumer, such as homes and business establishments.In recent years, in addition to measuring consumption, a built-in shut-off mechanism for earthquakes and a function to detect gas leaks have been incorporated. The "microcomputer meter" is widely used and contributes to the improvement of safety. In this microcomputer meter, there are various methods for measuring the gas flow rate, but for small-scale customers, there are many "membrane types" that use the displacement of the diaphragm.

  Inside the membrane type microcomputer meter, a diaphragm and a crank mechanism are connected, and a rotor incorporating a magnet rotates by displacement of the diaphragm. Furthermore, the change in the magnetic field due to the rotation of the magnet is measured by a magnetic sensor, the flow rate is calculated by a microcomputer based on the pulse transmitted from the magnetic sensor, the usage is integrated based on the flow rate, and security is provided as necessary. Work function. Usually, when the magnet makes one rotation, one or two pulses are transmitted from the magnetic sensor.

  The following patent documents are mentioned as examples of techniques related to the present invention. Patent Literature 1 discloses a gas meter that can measure the consumption of fuel gas with high accuracy. This gas meter incorporates an elastic film that expands and contracts in accordance with the flow of gas, and the displacement of the elastic film is transmitted to the support plate via the movement shaft. Further, a magnet is fixed to the support plate, and the magnet rotates and moves on an elliptical orbit with the displacement of the elastic film. In order to detect the movement of the magnet, a reed switch is used. In this document, a plurality of reed switches are arranged on the moving path of the magnet to improve the resolution, thereby realizing a highly accurate measurement. .

  Patent Document 2 discloses a flow channel structure of a membrane gas meter, which has a function of removing foreign substances from gas. This gas meter is provided with a bypass duct between the gas inlet and the rotary valve, and the inflowing gas is guided to a recess below the rotary valve by the bypass duct. As a result, the foreign matter falls to the bottom of the concave portion, and the gas from which the foreign matter has been removed can be sent to the rotary valve, thereby preventing the sliding surface of the rotary valve from being caught by the foreign matter and avoiding a measurement error.

JP-A-2003-202258 JP 2005-221316 A

  In recent years, "smart grids" aiming at efficient use of energy have been proposed, and as for gas meters, "smart meters" which further evolve "microcomputer meters" are being developed. In a smart meter, it is necessary to measure the gas flow rate more precisely, and as described above, one pulse or two pulses are transmitted with one rotation of a magnet, and the accuracy is insufficient, and a resolution of 8 pulses or 12 pulses is required. become. To achieve this, it is possible to take measures such as increasing the rotation of the magnet with a gear mechanism.However, due to space limitations, the sensitivity of the magnetic sensor is increased, small changes in the magnetic field are reliably detected, and a pulse is transmitted each time. It is desirable to do.

  Since the magnet used for measuring the flow rate is disposed without being isolated in the gas flow path, there is a possibility that foreign matter such as iron powder may be adsorbed by long-term use. When the adsorption of the foreign matter increases, the magnetic field also changes, and when the resolution is increased like a smart meter, it is expected that normal measurement becomes difficult. Therefore, in order to stably achieve high-accuracy measurement, a measure for suppressing adsorption of foreign matter is required.

  The present invention has been developed based on such circumstances, and an object of the present invention is to provide a flow meter of a gas meter capable of avoiding the influence of foreign matter in gas and maintaining high accuracy.

Said the first aspect of the present invention to solve the problems, a rotor that rotates in accordance with the flow rate of the gas, and a rectangular parallelepiped magnet which is placed on a pedestal provided on the end portion of the rotor, the rotation of the magnet A magnetic sensor for detecting a change in the magnetic field due to , and a protector that covers the outer periphery of the magnet, a flow measuring unit of a gas meter, wherein the pedestal is a flange-like shape that expands in the radial direction of the rotor, The magnetic sensor is opposed to the pedestal and is disposed on an extension of the central axis of the rotor.The protector is sandwiched between the magnetic sensor and the magnet, and the magnetic sensor Due to the centrifugal force caused by the rotation, the foreign matter adhering to the protective device can be moved toward the side end surface, and either the pedestal or the protective device has a guide extending along the side end surface of the magnet. Have multiple A wedge-shaped bulge is formed at the tip of the guide, and the claw is fitted to either the claw window of the protection tool or the back surface of the pedestal to attach the protection device to the pedestal. In this state, the claw and the guide are disposed behind the surface of the protector and do not protrude toward the magnetic sensor .

  The present invention is applied to a membrane gas meter that incorporates a diaphragm therein, converts the displacement of the diaphragm due to the flow of gas into rotational motion by a crank mechanism or the like, and measures gas consumption based on the number of revolutions. It is assumed that the mechanism for converting the displacement of the diaphragm into the rotational motion is exactly the same in the present invention as in the prior art. In order to convert the rotation into a rotational movement, a plurality of parts are used, such as an elbow that swings due to the displacement of the diaphragm and a small elbow connected to the elbow.

  The rotor is a shaft-shaped component that rotates in accordance with the displacement of the diaphragm.A gear or the like serving as a driving source is incorporated at one end of the rotor, and a pedestal that expands in a flange shape is provided at the other end. is there. In the present invention, the direction of the central axis of the rotor often depends on the internal structure of the gas meter, and may extend substantially horizontally or vertically. In addition, the rotor must be rotatably held by some method, but the specific configuration is various.

  The magnet used in the present invention is a rectangular parallelepiped permanent magnet whose back surface is mounted on a pedestal of a rotor and whose front surface is exposed to the outside. In order to prevent the magnet from falling off the pedestal, a guide for holding down the magnet is provided as necessary. The guide is a belt-like member protruding from a pedestal or the like, which comes into contact with the side end surface of the magnet and prevents the magnet from falling off.

  The magnetic sensor detects a change in the magnetic field due to the rotation of the magnet and emits an electric pulse, and is disposed so as to face the surface of the magnet with a small gap. Therefore, the magnet is sandwiched between the magnetic sensor and the pedestal. There are various types of magnetic sensors. In this field, an MR sensor using a magnetoresistive element is often used.

Protection, in addition to the surface of the magnet, a box-shaped cover to prevent the exposure of the side end face, and a variety of synthetic resin as a material, fixed to the base through the guide. With this protective device, each surface of the magnet is covered and the area exposed to the outside disappears. Therefore, even when a foreign substance such as a metal powder floats in the gas, it does not come into direct contact with the magnet. Since the protective device is made of a synthetic resin, it does not change the magnetic field and does not affect the magnetic sensor.

  Thus, by covering the magnet placed on the rotor with the protector, foreign matter such as metal powder floating in the gas does not come into direct contact with the magnet. Therefore, the attraction force acting on the foreign matter is also weakened, the foreign matter is separated from the magnet by the centrifugal force associated with the rotation of the rotor, and the change in the magnetic field due to the foreign matter is suppressed to a minimum, and the flow rate can be measured with high accuracy. By extending the central axis of the rotor in a substantially horizontal direction, gravity is applied to the foreign matter in addition to the centrifugal force, so that the foreign matter can be separated more efficiently.

In addition, the protector is detachable from the rotor. As a result , after use of the gas meter, inspection, replacement of the magnet, and the like can be smoothly performed. In order to realize “detachable”, a wedge-shaped claw is provided at the tip of a guide protruding from the pedestal or the protector, and this is fitted into a claw window provided on the other party . As described above, the claw fits into the claw window or the like to restrict the movement of the protector. However, if the claw is deformed by an external force, the claw is detached from the claw window or the like , and the protector can be removed.

The invention according to claim 2 shows a specific example of the protector, wherein the protector is transparent and the presence or absence of a magnet incorporated therein can be visually grasped. In the present invention, since each surface of the magnet is covered with the protective device, the presence or absence of the magnet inside cannot be visually grasped at the time of manufacturing or inspecting the gas meter. Therefore, in the final stage of the work, in order to check the presence or absence of the magnet, it is necessary to approach a tool or the like to determine the presence or absence of the suction, which is troublesome and may cause a failure later, forgotten the check work. However, by making the protective equipment transparent, the presence or absence of a magnet can be visually grasped, the checking operation becomes extremely simple, and a later problem is prevented.

  By covering the magnet mounted on the rotor with the protector as in the first aspect of the invention, foreign matter such as metal powder floating in the gas does not directly contact the magnet. Therefore, the attraction force acting on the foreign matter is also weakened, the foreign matter is separated from the magnet by gravity and centrifugal force caused by the rotation of the rotor, and the change in the magnetic field due to the foreign matter is minimized, so that the magnetic sensor can function normally. it can. With such features, a low-cost and high-precision “smart meter” can be realized without largely changing the internal structure of the gas meter.

In addition, by providing a wedge-shaped claw at the tip of the guide that holds the magnet and fitting it into a claw window or the like provided on the other side, the protector becomes detachable with respect to the rotor, and the gas meter At the time of manufacturing, the magnets can be incorporated without using an adhesive or the like, which saves time and labor. In addition, since it is detachable, inspection and replacement of magnets can be smoothly performed after use of the gas meter.

By making the protective device transparent as in the second aspect of the present invention, the presence or absence of a magnet incorporated in the protective device can be visually grasped from the outside, and the confirmation work at the time of manufacturing and inspection becomes extremely simple. , To prevent later failures.

FIG. 4 is a perspective view showing a configuration example in which the present invention is introduced into a gas meter of a rotary valve type, and details of the periphery of the rotor, in which a central axis of the rotor extends in a horizontal direction. In order to disclose the internal structure, the upper half in which the liquid crystal panel and the like are incorporated is illustrated in a detached state. FIG. 2 is a plan view illustrating an internal structure of the gas meter illustrated in FIG. 1 and a perspective view illustrating details of a protector thereof. It is a perspective view which shows the structural example at the time of introducing this invention to the gas meter of a fan-shaped valve system. In order to disclose the internal structure, the upper half in which the liquid crystal panel and the like are incorporated is illustrated in a detached state, similarly to FIG. FIG. 4 is a plan view illustrating an internal structure of the gas meter illustrated in FIG. 3 and a perspective view illustrating detailed shapes of a rotor and a protector thereof. FIG. 3 is a perspective view showing a configuration example when the present invention is introduced into a rotary valve type gas meter. Here, unlike FIG. 1, the center axis of the rotor is upright. In order to disclose the internal structure, the upper half in which the liquid crystal panel and the like are incorporated is illustrated in a detached state, as in the other drawings. FIG. 4 is a perspective view showing an example of the shape of a rotor and a protector, in which an upright rotor is depicted above the figure, and a protector provided with a guide is depicted below the figure.

  FIG. 1 shows a configuration example in which the present invention is introduced into a gas meter 11 of a rotary valve 55 type, and details of the periphery of a rotor 31 thereof. The central axis of the rotor 31 extends in the horizontal direction. In order to disclose the internal structure, the upper half in which the liquid crystal panel and the like are incorporated is illustrated in a detached state. The outer edge of the gas meter 11 is strictly protected by an outer case 15 made of metal, and a diaphragm (not shown) that is displaced by the flow of gas is incorporated therein. A blade shaft 17 is connected to the diaphragm, and the displacement of the diaphragm causes the two blade shafts 17 to swing regularly.

  A band-shaped elbow 18 is integrated with the upper end of each blade shaft 17, and each of the elbows 18 swings integrally with the blade shaft 17. Further, a small elbow 19 is attached to the tip of each elbow 18. The small elbow 19 is freely rotatable with respect to the elbow 18, and is regularly displaced by the swing of the individual blade shafts 17. The tips of the two small elbows 19 are attached to the outer edge of the crank gear 20, and the displacement of the small elbow 19 causes the crank gear 20 to rotate.

  The crank gear 20 is in close contact with a rotary valve 55 immediately below the crank gear 20, and these rotate integrally. The rotary valve 55 plays a role of switching the flow path of the gas flowing into the diaphragm according to its rotation. In FIG. 1, the place where the blade shaft 17 and the elbow 18 are disposed is a gas chamber 16 through which the gas flows when the gas meter 11 is used, from which the gas flows down through the rotary valve 55 to displace the diaphragm. Let it.

  The crank gear 20 meshes with the idle gear 21, and the idle gear 21 rotates the rotor 31 via the measurement gear 27. Although the central axis of the idle gear 21 is vertical, the central axis of the rotor 31 is horizontal, and the idle gear 21 and the measurement gear 27 have the same configuration as the crown gear. The measurement gear 27 is arranged on one end side of the rotor 31.

  The rotor 31 has a configuration in which a measurement gear 27 and a pedestal 36 are connected by a shaft 37. The measurement gear 27 meshes with the idle gear 21 as described above, and a magnet 58 is mounted on the pedestal 36. The magnet 58 is a rectangular parallelepiped permanent magnet that plays a role in measuring the rotation of the rotor 31. One of the magnets is necessarily an N pole and the other is an S pole. The back surface of the magnet 58 is brought into contact with the pedestal 36, and guides 38 and 39 for holding the side end surfaces of the magnet 58 protrude from the outer edge of the pedestal 36.

  The protector 41 is made of a synthetic resin material and is formed in accordance with the dimensions of the magnet 58 and the pedestal 36. The protector 41 covers the magnet 58 and the side end surface, and covers the outer periphery of the magnet 58 together with the pedestal 36. Protect. In order to fix the protector 41 to the rotor 31, a wedge-shaped claw 40 is provided at the tip of two opposing guides 38, and the protector 41 has a claw window into which the claw 40 fits. 46 are provided. Therefore, when the claw 40 is fitted into the claw window 46, the protector 41 is fixed to the rotor 31, and the magnet 58 is isolated from the gas chamber 16. When the pawl 40 is pushed inward, the pawl 40 is released from the pawl window 46, and the protector 41 can be removed from the rotor 31.

  A magnetic sensor 51 for detecting a magnetic field is arranged adjacent to the protective device 41. The magnetic sensor 51 is an MR sensor using a magnetoresistive element, and emits an electric pulse according to a change in a magnetic field. Actually, the gap between the protective device 41 and the magnetic sensor 51 is suppressed to a necessary minimum. In addition, if a transparent resin is used as the material of the protector 41, the presence or absence of the magnet 58 can be visually determined.

  FIG. 2 shows the internal structure of the gas meter 11 depicted in FIG. Two upright blades 17 are arranged inside the gas meter 11, and a small elbow 19 is attached to the tip of an elbow 18 that swings around each blade axis 17, and two small blades 19 are attached. The regular displacement of the elbow 19 causes the crank gear 20 and the concentric rotary valve 55 to rotate. An idle gear 21 meshes with the outer periphery of the crank gear 20. The central axis of the rotor 31 extends in the horizontal direction, and the measurement gear 27 of the rotor 31 meshes with the idle gear 21.

  At one end of the rotor 31, a magnet 58 is incorporated, but the magnet 58 is covered and protected by the protector 41, so that the magnet 58 does not come into direct contact with foreign matter. Therefore, the foreign matter attracted to the magnet 58 covers the surface of the protector 41, but the foreign matter is gradually separated by gravity or centrifugal force due to rotation. In addition, the pulse transmitted from the magnetic sensor 51 is transmitted to the control unit 52 via the electric wire 53, and the gas consumption is calculated.

  As depicted in the lower part of FIG. 2, the back side of the protector 41 is hollow, and the magnet 58 can be housed therein. In addition, by using a transparent resin as a material of the protector 41, even if the protector 41 is attached to the rotor 31, the presence or absence of the magnet 58 can be visually grasped, thereby preventing problems during manufacturing and inspection. .

  FIG. 3 shows a configuration example when the present invention is introduced into the gas meter 12 of the sector valve 56 type. In order to disclose the internal structure, the upper half in which the liquid crystal panel and the like are incorporated is illustrated in a detached state, similarly to FIG. As in FIG. 1, a diaphragm (not shown) that is displaced by the flow of gas is incorporated in the outer case 15, and the two blade shafts 17 swing regularly. At the upper end of the blade shaft 17, an elbow 18 bent in the middle is integrated, and the elbow 18 swings integrally with the blade shaft 17, and rotates the crank arm 22 ahead.

  The crank arm 22 swings the sector valve 56 via the crank rod 23 to intermittently feed gas into the diaphragm. Further, the screw gear 26 is rotated via the crank arm 22. The screw gear 26 is aligned concentrically with the rotor 32 in which the magnet 58 is incorporated, and with the rotation of the screw gear 26, the rotor 32 also rotates. Further, a protector 42 is incorporated in the rotor 32 to cover the magnet 58.

  FIG. 4 shows the internal structure of the gas meter 12 depicted in FIG. 3 and the detailed shapes of the rotor 32 and the protector 42 thereof. An upright blade shaft 17 is arranged inside the gas meter 12, and the crank arm 22 is connected to the elbow 18 swinging about the blade shaft 17 and a small elbow 19 attached to the tip thereof. Rotate. Then, the crank arm 22 swings the fan-shaped valve 56 via the crank rod 23. A screw gear 25 is incorporated in the center axis of the crank arm 22, and another screw gear 26 is arranged adjacent to the screw gear 25. The two screw gears 25 and 26 mesh with each other, and their central axes are orthogonal to each other.

  The central axis of the driven screw gear 26 on the driven side extends in the horizontal direction, and the rotor 32 is arranged concentrically with this. However, in order to prevent reverse rotation of the rotor 32, both are not directly connected but are connected via the clutch unit 28. Further, the rotor 32 has a shape in which a pedestal 36 is provided on one end side of a shaft 37, and guides 38 and 39 for holding the side end surfaces of the magnet 58 protrude from the outer edge of the pedestal 36. A claw 40 is formed at the tip. The protector 42 is provided with a claw window 46 into which the claw 40 fits, and the protector 42 is fixed to the rotor 32.

  A magnetic sensor 51 is arranged to face the protection device 42, and the transmitted pulse is transmitted to the control unit 52 via the electric wire 53, and the gas consumption is calculated. As described above, the present invention can be applied to all membrane gas meters, and the protector 42 is only slightly larger than the magnet 58, and can be easily incorporated into an existing gas meter.

  FIG. 5 shows an example of a configuration in which the present invention is introduced into the gas meter 13 of the rotary valve 55 type. Here, unlike FIG. 1, the central axis of the rotor 33 is upright. In order to disclose the internal structure, the upper half in which the liquid crystal panel and the like are incorporated is illustrated in a detached state, as in the other drawings. The gas meter 13 in this figure is of a rotary valve 55 type similarly to the one illustrated in FIG. 1, and has a common structure from the blade shaft 17 to the idle gear 21. However, the central axis of the rotor 33 is upright, and the idle gear 21 is incorporated at the lower end of the rotor 33. Further, a magnet 58 and a protector 43 are incorporated in an upper end portion of the rotor 33. Further, a magnetic sensor 51 (not shown) is disposed directly above the protective device 43.

  FIG. 6 shows examples of the shapes of the rotors 33 and 34 and the protectors 43 and 44. The upper part of the figure shows the upright rotor 33, and the lower part of the figure is provided with guides 48 and 49. Protective equipment 44 is depicted. The rotor 33 shown in the upper part of FIG. 6 is incorporated in the gas meter 13 shown in FIG. 5. The idle gear 21 is incorporated in the lower end of the shaft 37, and a disk-shaped pedestal 36 is formed on the upper end surface of the shaft 37. It is. A total of four guides 38 and 39 protrude from the upper surface of the pedestal 36, and two claws 40 are provided at the two opposing ends thereof, so that the protector 43 can be fixed.

  The lower rotor 34 in FIG. 6 is intended to be incorporated in the gas meter 11 or the like in FIG. 1, and the measurement gear 27 is incorporated in the end of the shaft 37. The pedestal 36 facing the measurement gear 27 has a simple rectangular shape. The protector 44 paired with the rotor 34 is provided with a total of four guides 48 and 49 on its side peripheral surface. These guides 48 and 49 do not hold the magnet 58, but contact the side end surface of the pedestal 36, and have a function of preventing displacement of the protector 44. Furthermore, a claw 50 is provided at the tip of the two opposing guides 48, which fits on the back surface of the pedestal 36 and fixes the protector 44 to the rotor 34.

11 gas meter (rotary valve system, rotor is lying down)
12 Gas meter (sector valve type)
13 Gas meter (rotary valve system, rotor upright)
15 Outer case 16 Gas chamber 17 Blade axis 18 Elbow 19 Small elbow 20 Crank gear 21 Idle gear 22 Crank arm 23 Crank rod 25 Screw gear 26 Screw gear 27 Measurement gear 28 Clutch part 31 Rotor 32 Rotor 33 Rotor 34 Rotor 36 Pedestal 37 Shaft 38 Guide (protruding from the rotor and with claws)
39 Guides (without protrusions and claws from rotor)
40 Claw 41 Protective device 42 Protective device 43 Protective device 44 Protective device 46 Claw window 48 Guide
49 Guides (without protrusions and claws from protective equipment)
Reference Signs List 50 claws 51 magnetic sensor 52 control unit 53 electric wire 55 rotary valve 56 fan-shaped valve 58 magnet

Claims (2)

A rotor (31 to 34) that rotates in accordance with the flow rate of the gas, the pedestal rectangular parallelepiped magnet which is placed on the (36) (58) provided at an end portion of said rotor (31 to 34), the magnet (58 A) a magnetic sensor (51) for detecting a change in the magnetic field due to the rotation, and a protector (41 to 44) for covering the outer periphery of the magnet (58) .
The pedestal (36) has a flange shape that expands in the radial direction of the rotor (31 to 34),
The magnetic sensor (51) is arranged opposite to the pedestal (36) and on an extension of the central axis of the rotor (31 to 34). The magnetic sensor (51) and the magnet (58) Between the protective devices (41 to 44) are sandwiched,
Due to the centrifugal force caused by the rotation of the rotors (31 to 34), the foreign substances adhering to the protectors (41 to 44) can be moved toward the side end faces,
Either the base (36) or the protector (44) is provided with a plurality of guides (38, 39, 48, 49) extending along the side end surface of the magnet (58). 38, 48) are formed with wedge-shaped bulges (40, 50) at the tips thereof.
In order to attach the protection tools (41 to 44) to the pedestal (36), the claws (40, 50) are provided with the claw windows (46) of the protection tools (41 to 43) or the back surface of the pedestal (36). In this state, the claw (40, 50) and the guide (38, 39, 48, 49) are disposed behind the surface of the protector (41 to 44). And a gas meter side portion of the gas meter, wherein the gas meter does not project toward the magnetic sensor (51) . 2. The flow meter according to claim 1, wherein the protector is transparent, and the presence or absence of the magnet embedded in the protector can be visually recognized. 3.

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