JP2014240844A - Gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology enabling gas to be shut off at the proper timing when water intrusion into an ultrasonic-type gas meter occurs.SOLUTION: In an ultrasonic-type gas meter 10, water coming in from a gas inflow port 5a flows down to a water storage part 40 through a water introducing hole 55 when flowing down to the lower part of a columnar portion 31. Moreover, a degassing hole 57 is formed in order to make water smoothly flowed into the water storage part 40. When the water storage part 40 is fully filled with water and furthermore water is intruded thereinto, water flows over a valve seat 32 of a shut-off valve 20 and starts dropping down from a communication hole. Water droplets dropped from the communication hole are collected into a water introducing groove 66 by the concentration projection 60 for water droplets and drop on a water introducing structure 2.

Description

  The present invention relates to a gas meter, and more particularly to a gas meter in which a gas flow rate is measured by an ultrasonic flow rate sensor.

  In order to measure the flow rate of gas, there is an ultrasonic gas meter using an ultrasonic flow rate sensor. Such an ultrasonic flow meter of an ultrasonic gas meter is composed of, for example, two acoustic transducers composed of piezoelectric vibrators and the like that are operated at an ultrasonic frequency and are arranged at a predetermined distance in the gas flow path. ing.

  In this ultrasonic gas meter, an ultrasonic signal generated by one acoustic transducer is received by the other acoustic transducer, and a propagation time during which the ultrasonic signal is propagated between the acoustic transducers is measured. Subsequently, the gas flow velocity is obtained intermittently based on the measured propagation time, and the passage flow rate is obtained by multiplying the flow velocity by the sectional area of the gas flow path and the intermittent time. Further, the integrated flow rate obtained by integrating the passing flow rate is displayed.

  In addition, there is an ultrasonic gas meter provided with a multilayer unit which is a rectifying means in order to appropriately measure the gas flow rate. This type of ultrasonic gas meter is a multi-layer unit that rectifies the flow of gas in an intermediate flow path formed between a gas inlet connected to a gas supply source and a gas outlet connected to a combustor or the like. Is provided. And the flow velocity of the gas which flows through the inside of a multilayer unit is measured with the ultrasonic type flow velocity sensor arrange | positioned at the side part of this multilayer unit.

  By the way, especially in the case of city gas, although it is very rare, the gas piping cracks due to earthquakes, typhoons, land subsidence, etc., rainwater enters, and water enters the flow path of the ultrasonic gas meter. May end up. Even when water accumulates in the multi-layer flow path even in the flow path, the propagation of ultrasonic waves becomes unstable, and erroneous flow rate measurement occurs.

  As a countermeasure, several techniques have been proposed. For example, when the amplification level of the ultrasonic signal received by the other transducer of the ultrasonic flow rate sensor is small and the propagation time is small, it is determined that the gas flow path is almost full. There is a sonic gas meter.

  In addition, there is a technique that can detect the entry of a small amount of water and issue a warning at an earlier stage (see, for example, Patent Document 1). FIG. 9 is a diagram showing a schematic configuration of an ultrasonic gas meter 100 employing such a technique. In this ultrasonic gas meter 100, a small amount of water is accurately guided to the sensor joint portion S by the water guide structure 102 formed in the multilayer unit 101, so that entry of a small amount of water is detected and blocked as early as possible. To do.

JP 2010-243421 A

By the way, the technique disclosed in Patent Document 1 is an early detection of water intrusion and its corresponding processing, which can accurately guide a small amount of water to the sensor joint portion by the water guide structure 102 formed in the multilayer unit 101. Gas cutoff was possible. However, the following issues remained.
(1) Even if less than a predetermined amount (for example, 50 cc) of water enters, it is desirable to perform measurement normally within a predetermined value (for example, 4% [use tolerance]).
(2) If a predetermined amount (for example, 50 cc) or more of water has entered, it is desired to immediately shut it off.
For example, if the gas meter shuts off due to a small amount of water of about 10 cc, it is expected that many shutoffs occur within the jurisdiction of the gas company. As a gas company, there is a problem that, despite a small amount of water that is within a safe range and within an allowable error, the measures for shut-off may be concentrated.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a technique capable of shutting off gas at an appropriate timing when water enters the gas meter.

  An aspect of the present invention includes a multilayer unit that is provided in a gas flow path, and in which a rectifying plate is arranged in multiple layers in a cylindrical case, and an ultrasonic flow rate that detects the flow rate of gas flowing in the multilayer unit with ultrasound. A gas meter comprising: a sensor; and a determination unit that determines whether water has entered the gas flow path based on an output of the ultrasonic flow rate sensor, wherein the ultrasonic flow rate sensor and the multilayer On the upstream side of the unit, a water storage part that temporarily stores intruded water and a water guide hole that guides water between the water storage part and the gas inlet of the gas flow path are provided.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which enables gas interruption | blocking at an appropriate timing when water entering in a gas meter can be provided.

It is sectional drawing of the principal part of the ultrasonic type gas meter based on embodiment of invention. It is a perspective view of the multilayer unit based on embodiment of invention. It is a functional block diagram of an ultrasonic sensor based on an embodiment of the invention. 1 is a front view of an internal structure of an ultrasonic gas meter according to an embodiment of the invention. 1 is a front view of an internal structure of an ultrasonic gas meter according to an embodiment of the invention. 1 is a perspective view of an internal structure of an ultrasonic gas meter according to an embodiment of the invention. 1 is a perspective view of an internal structure of an ultrasonic gas meter according to an embodiment of the invention. It is a bottom view of the meter body of an ultrasonic gas meter concerning an embodiment of the invention. It is sectional drawing of the principal part of the ultrasonic type gas meter based on a prior art.

Hereinafter, modes for carrying out the invention (hereinafter referred to as “embodiments”) will be described with reference to the drawings. In the present embodiment, the technique disclosed in Patent Document 1 is improved to enable the following processing.
(1) Even if less than a predetermined amount (for example, 50 cc) of water enters, the instrument error is normally measured within a predetermined value (for example, 4% [use tolerance]).
(2) When a predetermined amount (for example, 50 cc) or more of water has entered, immediately shut off.
As a result, it is possible to prevent the gas meter from being frequently interrupted by entering a small amount of water of about 10 cc, for example. This will be specifically described below.

  FIG. 1 is a cross-sectional view schematically showing a main part of an ultrasonic gas meter 10 according to the present embodiment. FIG. 2 is a perspective view showing the multilayer unit 1. FIG. 3 is a functional block diagram of the main part of the ultrasonic gas meter 10. In FIG. 1, the same members as those in FIG. 9 are denoted by the same reference numerals. 1 (this embodiment) and FIG. 9 (prior art) are different from each other in that a water reservoir 40, a water guide hole 55, a gas vent hole 57, a water droplet concentrating protrusion 60 and a water guide groove 66 are mainly added. In the point. 4 to 8 show a more detailed outline of the main structure of the ultrasonic gas meter 10 focusing on the additional configuration. 4 and 5 are front views showing the internal structure of the ultrasonic gas meter 10. In particular, FIG. 4 shows a state in which the water reservoir 40 is sealed with a water reservoir lid 42, and FIG. The state which removed the part lid | cover 42 is shown, and also both figures have shown the state in which the fixed amount of water is stored in the water storage part 40. FIG. 6 is a perspective view from the front upper direction of the ultrasonic gas meter 10, and FIG. 7 is a perspective view from the lateral direction, showing a state where the water storage lid 42 is removed. Further, FIG. 8 is a bottom view of the meter body 50 of the ultrasonic gas meter 10. In the front view and the bottom view, the depth is expressed.

  First, a basic configuration (hereinafter referred to as “basic structure”) similar to FIG. 9 (prior art) will be described, followed by a characteristic structure (hereinafter referred to as “improved structure”) in the present embodiment. The water storage section 40, the water guide hole 55, the gas vent hole 57, the water droplet concentrating protrusion 60, and the water guide groove 66 will be described.

  As shown in FIGS. 1 and 2, the ultrasonic gas meter 10 includes a multilayer unit 1 similar to that shown in FIG. 9 shown in the related art. Further, the meter body 50 includes a gas inlet 5a that communicates with a pipe of a gas supply source, a gas outlet 5b that is connected to a combustor and the like, an inlet channel portion 51 that communicates with the gas inlet 5a, a gas An outlet channel portion 52 communicating with the outlet port 5b, and an intermediate channel portion 5c formed between the meter body 50 and the bottom lid 5e, communicating between the inlet channel portion 51 and the outlet channel portion 52. And. And the multilayer unit 1 is provided in the intermediate | middle flow-path part 5c, and the ultrasonic type flow velocity sensor 90 (not shown) arrange | positioned at the side part of this multilayer unit 1 (refer FIG.3, FIG.8 (b) and (c)). ) To measure the flow velocity of the gas flowing in the multilayer unit 1.

  The inlet flow channel portion 51, the outlet flow channel portion 52, and the intermediate flow channel portion 5c are fixed to each other in a state in which the space between them is kept airtight. In the inlet channel 51, the intermediate channel 5c, and the outlet channel 52, a gas as a fluid to be measured flows inward in order. For this reason, the space inside the inlet channel 51, the intermediate channel 5c, and the outlet channel 52 constitutes a gas channel. And the below-mentioned water conveyance structure 2 is formed in the upper surface part 1a which is an upper surface of the multilayer unit 1 arrange | positioned in the intermediate flow path part 5c. Further, a part of the multilayer unit 1 is a sensor joint portion S that is joined to the ultrasonic flow rate sensor 90. A gas shutoff valve 20 (see, for example, FIG. 4) that shuts off the gas flow path by closing the valve is provided upstream of the intermediate flow path portion 5c.

  More specifically, a cylindrical columnar portion 31 is formed in the path between the gas inlet 5a and the bottom 5d. Here, the cylindrical portion 31 is formed to extend horizontally in the front-rear direction of the drawing. And the valve seat 32 for arrange | positioning the gas cutoff valve 20 is formed in the end surface side of the near side of the cylindrical part 31 in the figure. Furthermore, a communication hole 33 that communicates with the space toward the intermediate flow path portion 5c where the multilayer unit 1 is disposed is provided on the back side. When the gas shut-off valve 20 is in the open state, the gas is supplied from the gas inlet 5a through the communication hole 33 to the intermediate flow path portion 5c (multilayer unit 1).

  As shown in FIG. 3, the ultrasonic gas meter 10 includes two gas meters that are arranged to face each other so as to be separated from each other by a distance L in the gas flow path and to form a predetermined angle with respect to the gas flow direction Y. It has acoustic transducers TD1, TD2. The acoustic transducers TD 1 and TD 2 constitute an ultrasonic flow rate sensor 90.

  The two acoustic transducers TD1 and TD2 are, for example, piezoelectric vibrators that operate at an ultrasonic frequency, and each of the transducers TD1 and TD2 is transmitted through a transducer interface (I / F) circuit 11a and 11b, respectively, and a transmission circuit 12 and a reception circuit. 13 is connected. The transmission circuit 12 transmits a signal for generating an ultrasonic signal by driving one of the transducers TD1 and TD2 in the form of a pulse burst under the control of the control unit 14 constituted by a microcomputer or the like.

  The receiving circuit 13 includes an amplifier 13a that receives signals from the other transducers TD1 and TD2 that have received the ultrasonic signal that has passed through the gas flow path and amplifies the ultrasonic signal to a predetermined intensity. The amplification degree of the amplifier 13a can be adjusted by the control unit 14.

  The control unit 14 performs various processes according to the program. And it has the measuring function which measures gas flow velocity for every sampling time using two transducers TD1 and TD2, and measures the instantaneous flow rate by multiplying the measured gas flow velocity by the cross-sectional area of the gas flow path. Further, in the present embodiment, the control unit 14 includes a determination function (determination means) that determines whether water has entered the gas flow path based on the amplification degree of the received ultrasonic signal. The CPU 14a can distinguish and determine whether the intrusion is less than a predetermined amount of water or more than a predetermined amount of water in the gas flow path.

  Here, the amplification degree of the received ultrasonic signal varies depending on the amount of water that has entered. For example, when a small amount of water, such as 20 to 70 cc, enters the gas flow path, ultrasonic waves are scattered, refracted, attenuated, etc. at the interface between water and gas, and the propagation becomes unstable. For this reason, the received ultrasonic signal tends to be small, and the amplification degree tends to increase. On the other hand, when a large amount of water of 80 cc or the like enters the gas flow path and becomes almost full, the space between the acoustic transducers TD1 and TD2 is filled with the same medium. For this reason, there is no interface between water and gas, scattering, refraction, attenuation and the like are less likely to occur, and the degree of amplification tends to decrease. For these reasons, the degree of amplification tends to increase for the ingress of a small amount of water, and tends to decrease for the ingress of a large amount of water.

  Therefore, the control unit 14 can determine that less than a predetermined amount of water has entered by monitoring the amplification degree or that more than a predetermined amount of water has entered. In the present embodiment, as will be described later, since the water gradually accumulated in the water storage section 40 is full and overflowing water or a large amount of water is detected and directly reaches the water guide structure 2, it is a small amount of water. However, the gas shutoff valve 20 is immediately shut off.

  Next, the multilayer unit 1 will be described with reference to FIG. As shown in the figure, the multilayer unit 1 is formed by accommodating the rectifying plate 3 in a rectangular parallelepiped cylindrical case 1A, and has an inlet side opening 1-1 that opens to the inlet channel 51 side, It has an outlet side opening 1-2 that opens to the outlet channel portion 52 side. Moreover, the opening part 1b is formed in the location close | similar to the inlet side opening part 1-1 side of the side surface of the cylindrical case 1A, and the circumference | surroundings of this opening part 1b become the sensor junction part S (S '). Then, ultrasonic waves are emitted from the acoustic transducer TD2 to the internal gas via the sensor joint portion S. The rectifying plate 3 is formed in a flat plate shape, arranged in multiple layers in parallel to each other at intervals, and is accommodated in the central portion of the cylindrical case 1A. The rectifying plate 3 is arranged in parallel with the longitudinal direction of the cylindrical case 1A, and makes the flow velocity of the gas flowing through the multilayer unit 1 uniform. Thereby, the gas flow rate can be accurately measured.

  Furthermore, this multilayer unit 1 is provided with a water guiding structure 2 (water receiving tray, water receiving tray) that constitutes a water guiding structure on the upper surface 1a of the cylindrical case 1A. This water guide structure 2 is a separate member from the cylindrical case 1A, and is fitted into a positioning shape formed on the upper surface portion 1a, and is fixed at a predetermined position when the multilayer unit 1 is assembled to the intermediate flow path portion 5c. The In principle, it is not necessary to use fixing means such as an adhesive or screwing, but these fixing means may be used as necessary. As shown in the photograph at the upper left of the figure, the water conveyance structure 2 has a bank portion 29 extending from the position of the upper side portion of the inlet side opening 1-1 to the opening 1b along both sides of the upper surface 1a of the cylindrical case 1A. In addition, the bank portion 29 forms an uneven (concave) water channel 29 a on the inside thereof. The bank portion 29 and the water channel 29a constitute a water guide structure 2 that extends to the upper surface 1a of the cylindrical case 1A up to the sensor joint portion S and guides water to the sensor joint portion S. Although illustration is omitted, a packing (not shown) is provided around the sensor joint portion S. And the water droplet which fell on the upper part of the entrance side opening part 1-1 flows to the opening part 1b, ie, the sensor junction part S, surrounded by this bank part 29, and the water which flowed out to the sensor junction part S is the inner side of packing. Accumulate. As a result, similar to the above embodiments, even a small amount of water can be detected at an early stage.

  Moreover, since such a water conveyance structure 2 is comprised by the cylindrical case 1A and another member, there exist the following effects. That is, the multilayer unit 1 is manufactured by insert molding. However, if the multilayer unit 1 and the water guide structure 2 have a complicated structure, insert molding becomes difficult. More specifically, in order to provide a bank portion, a hollow portion, and an inclined portion in the cylindrical case 1A of the multilayer unit 1, the molding die of the multilayer unit 1 is arranged in a direction perpendicular to the mold drawing direction. There is a problem that it is necessary to provide a slider, the molding of the multilayer unit 1 is complicated, the number of molding processes is increased, and the quality is not stable. However, if a separate water-conducting structure 2 is produced, the molding of the multilayer unit 1 itself does not increase the number of steps and the quality is stabilized. In addition, by using the same multilayer unit 1, an ultrasonic gas meter 10 having a water blocking function and an ultrasonic gas meter (not shown) having no water blocking function can be configured, and parts can be shared. This is effective in terms of cost reduction.

Next, the description will be made focusing on the improved structure added to the above basic structure.
As a characteristic structure of the present embodiment, the ultrasonic gas meter 10 includes a water storage unit 40 at a substantially central position of the meter body 50. As illustrated, the water storage section 40 has a substantially trapezoidal cross section. As shown mainly in FIG. 4, the water reservoir 40 is sealed by a trapezoidal rubber packing 41 and a trapezoidal water reservoir lid 42. Specifically, a packing base 43 is formed around the opening end (the front side in the figure) of the water storage section 40 so as to surround the opening portion. The rubber packing 41 is disposed on the packing pedestal 43, and then the water storage section lid 42 is attached, whereby the water storage section 40 is sealed.

  If the volume of the water storage section 40 is designed to be 50 cc, for example, until the predetermined amount (for example, 50 cc) of water enters, the instrumental error is normally measured within a predetermined value (for example, 4% [use tolerance]). It can be performed and can be shut off immediately when a predetermined amount (for example, 50 cc) is exceeded.

  From the lower part of the cylindrical part 31 to which the gas shut-off valve 20 is attached to the water storage part 40, a water introduction hole 55 is formed to penetrate therethrough. When the water that has entered from the gas inlet 5 a falls to the lower part of the cylindrical part 31, it flows through the water introduction hole 55 and falls into the water storage part 40.

  Since the water storage section 40 is sealed by the rubber packing 41 and the water storage section lid 42, a gas vent hole 57 is formed in order to smoothly flow water into the water storage section 40. Here, a gas vent hole 57 penetrates from the cylindrical part 31 to the water storage part 40 in the upper part of the water guide hole 55 in parallel with the water guide hole 55. At the same time as water flows into the water storage section 40 through the water guide hole 55, the gas accumulated in the water storage section 40 is discharged to the cylindrical section 31 through the gas vent hole 57.

  When the water flows in a predetermined amount or more, the water storage section 40 becomes full, and when water further enters, the water storage section 40 gets over the valve seat 32 of the columnar section 31 to which the shutoff valve 20 is attached, and begins to hang down from the communication hole 33. In order to concentrate the dripping water drops on one point, as shown in FIG. 1 and FIG. 8A, in the space (gas flow path) below the gas cutoff valve 20 (columnar portion 31), A water droplet concentrating protrusion 60 having an inverted square cone shape is formed just at the lower portion of the cylindrical portion 31. Specifically, in the water droplet concentrating protrusion 60, a slope 62 that is a pyramid surface of a quadrangular pyramid is formed so as to extend substantially continuously downward from a surface constituting the communication hole 33. That is, it is configured such that water droplets that hang down the constituent surface of the communication hole 33 can be smoothly transmitted to the slope 62 of the water droplet concentrating protrusion 60. A concentrating portion 64 is formed at the top of the quadrangular shape. Due to the presence of the water droplet concentrating protrusions 60, the water droplets dripping from the communication hole 33 are not dispersed and dropped around, but are collected and dropped in a water guide groove 66 described later.

  A water guide groove 66 having a predetermined depth is formed on the wall surface 65 where the concentrated portion 64 is formed so as to extend downward. The water drops dripping down the water drop concentrating protrusion 60 drop down on the water guide groove 66 and fall on the water guide structure 2. Since there is this water guide groove 66, it is possible to drop water droplets at a desired position, more specifically, the water channel 29 a inside the bank portion 29.

  In this way, by adding the water storage section 40, the water guide hole 55, the gas vent hole 57, the water droplet concentrating protrusion 60, and the water guide groove 66, which are improved structures, to the basic structure, a predetermined amount of water is contained in the ultrasonic gas meter 10. As described above, when the water storage unit 40 becomes full, water is immediately introduced to the sensor joint portion S, and a blocking operation is performed.

  In addition, when a large amount of water flows into the ultrasonic gas meter 10 at once, the water does not collect in the water storage section 40 through the water guide hole 55, but passes over the valve seat 32 at once and the water guide structure through the communication hole 33. As soon as it falls to the body 2, water is guided to the sensor joint S, and a blocking operation is performed. In such a situation, since the instrumental error is not compensated, it is desirable to immediately shut off, and the ultrasonic gas meter 10 can properly perform the shutoff operation.

  Furthermore, in the ultrasonic gas meter 10 having the above-described structure, it is confirmed from the experimental results that the water accumulated in the water storage unit 40 evaporates about 1 cc per day in the flowing gas. did it. Therefore, the water accumulated in the water storage unit 40 does not stay in the ultrasonic gas meter 10 until the expiration of the test, and no problem in use occurs.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it is understood by those skilled in the art that various modifications can be made to each of those components and combinations thereof, and such modifications are also within the scope of the present invention. The ultrasonic gas meter 10 according to the embodiment detects water intrusion by using the output of the ultrasonic sensor 90. However, if the output of the ultrasonic flow rate sensor 90 is used, The method for detecting intrusion is not limited to that of the embodiment, and other methods may be used. In addition, the water guide structure 2 may be integrally formed as long as the shape does not cause difficulty in molding. For example, various structures as shown in Patent Document 1 may be adopted. it can. Further, even if the water droplet concentrating protrusion 60 and the water guide groove 66 are provided without providing the water storage section 40, a certain effect can be obtained from the viewpoint of properly guiding water to the water guide structure 2. On the other hand, even if the water droplet concentrating protrusion 60 and the water guide groove 66 are not provided and only the water storage section 40 is provided, a certain effect can be obtained from the viewpoint of allowing a certain amount of water accumulation.

DESCRIPTION OF SYMBOLS 1 Multilayer unit 1-1 Entrance side opening 1-2 Exit side opening 1A Cylindrical case 1a Upper surface part 1b Opening part 2 Water transfer structure 5a Gas inflow port 5b Gas outflow port 5c Intermediate flow path part 5e Bottom cover 10 Ultrasonic type Gas meter 14 Control unit 20 Gas shut-off valve 29 Bank 29a Water channel 31 Cylindrical part 32 Valve seat 33 Communication hole 40 Water storage part 50 Meter body 55 Water introduction hole 57 Gas vent hole 60 Water droplet concentrating protrusion (water concentrating means)
62 slope 64 concentration part 65 wall surface 66 water guide groove (water guide means)
90 Ultrasonic sensor

Claims (1)

A multilayer unit provided in the gas flow path, in which a rectifying plate is arranged in multiple layers in a cylindrical case, an ultrasonic flow rate sensor for detecting the flow rate of gas flowing in the multilayer unit with ultrasonic waves, and the ultrasonic type A gas meter comprising: a determination means for determining whether water has entered the gas flow path based on the output of the flow velocity sensor;
On the upstream side of the ultrasonic flow rate sensor and the multilayer unit, a water storage part for temporarily storing infiltrated water,
Between the water reservoir and the gas inlet of the gas flow path,
A gas meter comprising:

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