JP2017129391A - Gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic gas meter with which it is possible to reduce the number of parts or assembly man-hours.SOLUTION: A strainer 15 includes a cylindrical member 16 having an outer circumferential shape that corresponds to the inner wall surface of an inlet flow path 12a, and an end wall 17 provided continuously to one end of the cylindrical member 16 and equipped with an opening that constitutes a gas passageway 17a. The strainer 15 is held in place by the inner wall surface of the inlet flow path 12a.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a gas meter.

  Conventionally, various types of gas meters for measuring the flow rate of gas are known, for example, an ultrasonic gas meter. The ultrasonic gas meter is equipped with a pair of acoustic transducers (ultrasonic flow velocity sensors) composed of piezoelectric vibrators and the like that operate at an ultrasonic frequency, and the pair of ultrasonic flow velocity sensors are constant in the gas flow path. They are separated by a distance.

  A gas inlet connected to a gas supply source and a gas outlet connected to a combustor or the like are provided in the body main body of the gas meter, and the inside of the body main body extends from the gas inlet to the gas outlet. A gas flow path is formed. The gas flow path includes an inlet flow path portion that communicates with the gas inlet and flows gas vertically, an outlet flow path portion that communicates with the gas outlet and flows gas vertically, and an inlet flow path portion and an outlet. It has an intermediate flow path portion that communicates with the flow path portion, and has a flow path shape that is bent into a substantially U shape.

  The intermediate flow path is provided with a cylindrical flow path case in which a rectifying plate for rectifying the gas flow is disposed, and the gas from the inlet flow path to the outlet flow path is Flows through the case. A pair of ultrasonic flow rate sensors are arranged on the side of the flow path case, and the flow velocity of the gas flowing in the flow path case is measured through the pair of ultrasonic flow rate sensors.

  By the way, because the inlet channel section includes a shut-off valve or the like for blocking the gas flow, the gas once flows to the back side of the gas meter, or flows in a part where the channel diameter is partially reduced. It has a channel structure. Due to this complicated flow path structure, turbulence occurs in the gas flowing through the inlet flow path section, and the turbulent gas flows into the flow path case, resulting in variations in flow rate measurement and an increase in flow rate error. May end up.

  Thus, for example, Patent Document 1 discloses a structure in which a rectifying plate for rectifying a gas flow is disposed in the vicinity of an inlet of a measurement pipe (flow path case). The current plate is attached to the flow path member from the bottom surface side of the body main body. Further, for example, Patent Document 2 discloses a structure in which a rectifying plate is provided on an upper wall portion formed in an inlet flow path portion. A boss having a screw hole is provided on the upper wall portion so as to protrude along the gas flow direction. Moreover, the baffle plate is equipped with the screw hole penetrated in the plate | board thickness direction, and is fixed to a boss | hub with a screw.

JP 2009-186429 A JP 2010-008116 A

  However, according to the methods disclosed in Patent Documents 1 and 2, since it is necessary to fix and fix the flat plate-like rectifying plate to the gas flow path, the number of parts increases or the number of assembling steps increases. There is an inconvenience of doing. Moreover, since the assembly work is performed in a narrow gas flow path, the workability is poor, leading to an increase in the number of assembly steps.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an ultrasonic gas meter capable of reducing the number of parts and the number of assembling steps.

  In order to solve such a problem, the present invention provides a body body having a series of gas flow paths extending from a gas inlet to a gas outlet and having an open bottom surface and a bottom surface of the body body. And an under cover that covers the bottom side of the body body and closes the gas flow path, and is disposed in the gas flow path, and the sensor is assembled to the cylindrical flow path case. And a strainer that is arranged in the vicinity of the measurement unit and rectifies the flow of gas flowing in the gas flow path, and the strainer corresponds to the inner wall surface of the gas flow path. A cylindrical member having an outer peripheral shape, and an end wall provided with an opening serving as a gas passage, which are connected to one end of the cylindrical member, are accommodated and held by the inner wall surface of the gas flow path. .

  Here, in the present invention, the gas channel communicates with the inlet channel portion communicating with the gas inlet, the outlet channel portion communicating with the gas outlet, the inlet channel portion and the outlet channel portion, respectively. The flow path is formed of an intermediate flow path portion in which the measurement unit is accommodated, and has a flow path shape bent in a substantially U shape, and the strainer is a flow path of one or both of the inlet flow path portion and the outlet flow path portion. It is preferable to arrange in the part.

  Further, in the present invention, the strainer is fitted in the flow path portion so that the end wall is positioned at the upper end of the cylindrical member, and the lower end of the strainer is held by a receiving portion formed in the under cover. preferable.

  According to the present invention, since the strainer is accommodated and held in the gas flow path by fitting the cylindrical strainer into the gas flow path, the strainer can be easily assembled. In this case, since a separate member for assembling and fixing is not necessary, the number of parts and the number of assembling steps can be reduced. In addition, since it is not necessary to perform complicated operations such as screwing in a narrow flow path, the workability is improved and the number of assembling steps can be reduced.

Front view showing a configuration of an ultrasonic gas meter according to the present embodiment Sectional drawing which shows typically the internal structure of the ultrasonic type gas meter which concerns on this embodiment The perspective view which shows the principal part of an under cover typically The perspective view which shows the structure of a strainer Explanatory drawing schematically showing the state after the strainer is assembled Explanatory drawing schematically showing the state before the strainer is assembled

  FIG. 1 is a front view showing a configuration of an ultrasonic gas meter according to the present embodiment. FIG. 2 is a cross-sectional view schematically showing the internal structure of the ultrasonic gas meter according to the present embodiment. The ultrasonic gas meter according to the present embodiment is a gas meter that measures a gas flow rate with a pair of ultrasonic flow velocity sensors that transmit and receive ultrasonic waves. The ultrasonic gas meter is mainly composed of a meter body 10, an under cover 20, and a measurement unit 30.

  The meter body 10 includes a body main body 10a formed of a metal material such as aluminum or an aluminum alloy, and a resin front cover 10b provided on the front surface thereof. The meter body 10 is controlled to a gap between the body main body 10a and the front cover 10b. Contains substrates and the like.

  The body main body 10a includes a gas inlet 11a to which piping from a gas supply source is connected and a gas outlet 11b to which a combustor and the like are connected. A series of gas passages 12 extending from the gas inlet 11a to the gas outlet 11b are provided inside the body main body 10a.

  The gas channel 12 includes an inlet channel portion 12a, an intermediate channel portion 12b, and an outlet channel portion 12c, and has a channel shape that is bent into a substantially U shape. These channel portions 12a to 12c are arranged in the order of the inlet channel portion 12a, the intermediate channel portion 12b, and the outlet channel portion 12c from the gas inlet port 11a to the gas outlet port 11b.

  The inlet channel portion 12a communicates with the gas inlet port 11a and is formed along the vertical direction. A circular opening 12a1 is set at an intermediate portion of the inlet channel portion 12a. When the gas flowing in from the gas inlet 11a flows downward, it flows from the front side (front side) to the back side (rear side) of the meter body 10 at the opening 12a1, and then turns downward again to change downward. Flowing. The opening 12a1 is provided with a shut-off valve (not shown). When the valve body of the shut-off valve protrudes from the front side toward the back side and closes the opening 12a1, the gas flow can be shut off in the middle of the inlet flow path part 12a.

  The outlet channel portion 12c communicates with the gas outlet port 11b and is formed along the vertical direction in the same manner as the inlet channel portion 12a.

  The intermediate channel portion 12b communicates with the inlet channel portion 12a and the outlet channel portion 12c, respectively, and is formed along the left-right direction. The measurement unit 30 is accommodated in the intermediate flow path portion 12b.

  The bottom surface of the body body 10a has an open structure, and a gas flow path 12 formed inside the body body 10a appears on the opened bottom surface side. The under cover 20 is disposed on the bottom surface of the meter body 10, covers the bottom surface side of the body body 10a, and closes the gas flow path 12. The under cover 20 is formed of a metal material such as aluminum or an aluminum alloy, like the body main body 10a.

  FIG. 3 is a perspective view schematically showing a main part of the undercover 20. A concave portion 21 is formed along the longitudinal direction on the upper surface of the under cover 20, that is, the surface facing the inside of the meter body 10. The recess 21 includes an inlet recess 21a corresponding to the inlet channel portion 12a, an intermediate recess 21b corresponding to the intermediate channel portion 12b, and an outlet recess 21c corresponding to the outlet channel portion 12c.

  The inlet recess 21a and the outlet recess 21c are formed wider than the intermediate recess 21b and have a larger distance (depth) to the bottom. The peripheral shapes of the inlet recess 21a and the outlet recess 21c on the upper surface side of the under cover 20 are set so as to correspond to the peripheral shapes of the inlet channel portion 12a and the outlet channel portion 12c on the bottom surface side of the body main body 10a. On the other hand, the intermediate recess 21 b is set so that its width corresponds to the outer width of the flow path case 31 of the measurement unit 30 and its depth is about half of the height of the flow path case 31.

  A receiving portion 21a2 is formed on the peripheral side wall 21a1 of the entrance recess 21a. In the present embodiment, the receiving portion 21a2 is set at two locations corresponding to the front side and the back side of the meter body 10, respectively. The receiving portion 21a2 bulges toward the inside of the entrance recess 21a, and is continuously formed along the height direction (vertical direction) of the peripheral side wall 21a1.

  The measurement unit 30 is mainly configured by a flow path case 31, a pair of ultrasonic flow velocity sensors 32, and a control board 33. The lower half of the flow path case 31 is inserted and fixed in the intermediate recess 21b of the under cover 20, and is disposed in the intermediate flow path portion 12b so that the axial direction of the flow path case 31 is horizontal. In this arrangement state, the pair of ultrasonic flow rate sensors 32 is assembled on the upper surface of the flow path case 31.

  The flow path case 31 is a long cylindrical member set longer than the distance between the central axis of the gas inlet port 11a and the central axis of the gas outlet port 11b, and one opening end portion of the channel case 31 is the inlet flow channel. It arrange | positions so that the other opening edge part may face the exit flow path part 12c at the path part 12a. The gas that has flowed through the inlet flow channel portion 12a flows into the flow channel case 31 from one opening end, flows through the flow channel case 31, and then flows from the other open end to the outlet flow channel portion 12c. And flows out. A plurality of rectifying plates (not shown) for rectifying the gas flow are stacked in the flow path case 31.

  The flow path case 31 includes two O-ring holding portions 36 that are provided at a required interval in the longitudinal direction. The two O-ring holding portions 36 are portions where rubber-like O-rings are provided, and are located at both ends of the intermediate recess 21b when the flow path case 31 is disposed in the intermediate recess 21b. For this reason, the O-ring held by the O-ring holding portion 36 is in close contact with the intermediate recess 21b, and this close-contact portion functions as a seal portion. Thereby, the sealing performance is ensured so that the gas in the inlet recess 21a of the under cover 20 does not flow into the outlet recess 21c through the gap between the flow path case 31 and the intermediate recess 21b. The O-ring is also in close contact with the meter body 10 side so that no gap is generated between the flow path case 31 and the meter body 10.

  In the pair of ultrasonic flow rate sensors 32, the ultrasonic signal transmitted from one ultrasonic flow rate sensor 32 is reflected by the bottom surface of the flow path case 31 and received by the other ultrasonic flow rate sensor 32. It is a reflection type unit.

  The control board 33 performs ultrasonic signal transmission processing, propagation time measurement, and the like. A protective case (not shown) for protecting the control board 33 is assembled on the upper surface of the flow path case 31.

  Hereinafter, the strainer 15 which is one of the features of the present embodiment will be described. Here, FIG. 4 is a perspective view showing the configuration of the strainer 15. FIG. 5 is an explanatory diagram schematically illustrating a state after the strainer 15 is assembled, and FIG. 6 is an explanatory diagram schematically illustrating a state before the strainer 15 is assembled. The strainer 15 is disposed in the inlet flow passage 12a and rectifies the flow of gas flowing into the measurement unit 30, that is, the flow of gas flowing through the inlet flow passage 12a. The strainer 15 is disposed in the vicinity of the measurement unit 30, particularly in a downstream region from the opening 12 a 1 in the inlet flow path portion 12 a.

  The strainer 15 is mainly composed of a cylindrical member 16 extending in the vertical direction and an end wall 17.

  The cylindrical member 16 is formed in a substantially square cylindrical shape, and the outer peripheral shape thereof has a shape corresponding to the inner wall surface of the inlet channel portion 12a. The lower end 16c of the cylindrical member 16 remains open. Further, an opening 16 a necessary for arranging the flow path case 31 is set in a part of the cylindrical member 16.

  The end wall 17 is connected to the upper end of the cylindrical member 16 and constitutes a surface that is substantially perpendicular to the gas flow in the inlet channel portion 12a. A gas passage 17a having an opening set in a required shape is formed in a part of the end wall 17. The gas passage 17a has a function of rectifying the flow of gas downstream from the end wall 17 by allowing the gas flowing through the inlet passage portion 12a to pass through the gas passage 17a. The gas passage 17a is set in a required shape determined from the rectifying function. In the present embodiment, the gas passage 17a has a substantially rectangular first opening 17a1 formed in the central portion of the end wall 17, and the first opening 17a1. It is composed of a substantially rectangular second opening 17a2 which is adjacent and formed wide in the front-rear direction.

  In the strainer 15, a protruding portion 16 b that protrudes outward is formed on the peripheral edge of the cylindrical member 16 on the lower end 16 c side. The protrusions 16b are set on both sides of the opening 16a. A rib 16b1 having a predetermined height is formed on the upper surface of each protrusion 16b. By this rib 16b1, a margin with respect to the height direction (vertical direction) is given to the protrusion 16b.

  On the other hand, the groove part 10a1 corresponding to the two projection parts 16b is set in the required position of the peripheral part of the inlet flow path part 12a in the bottom face side of the body main body 10a. The protruding portion 16b and the groove portion 10a1 are in a relationship of fitting with each other when the strainer 15 is assembled to the inlet channel portion 12a (see FIG. 5). The height of the protrusion 16b including the rib 16b1 is set to be slightly larger than the depth of the groove 10a1.

  Further, a boss portion 17 b made of a cylindrical projection is provided upright on the end wall 17 of the strainer 15. On the other hand, an upper wall surface is formed at a required position of the inlet channel portion 12a of the body main body 10a, and a convex portion (not shown) corresponding to the boss portion 17b is set on the upper wall surface. The boss part 17b and the convex part have a relationship of fitting with each other when the strainer 15 is assembled to the inlet channel part 12a (see FIG. 2).

  The strainer 15 is assembled to the inlet channel portion 12a by fitting the strainer 15 into the inlet channel portion 12a from the bottom surface side of the body main body 10a. As shown in FIG. 6, the strainer 15 is fitted into the inlet channel portion 12a with the end wall 17 at the head.

  At this time, the boss portion 17b set on the end wall 17 and the convex portion of the inlet flow passage portion 12a are fitted, whereby the strainer 15 is positioned. Similarly, the pair of protrusions 16b set on the cylindrical member 16 are fitted into the pair of grooves 10a1 set on the inlet channel portion 12a on the bottom surface side of the body main body 10a.

  At this time, due to the setting of the rib 16b1 of the protrusion 16b, the lower end of the strainer 15 (the lower end 16c of the cylindrical member 16) fitted into the inlet flow passage 12a slightly protrudes from the peripheral edge of the inlet flow passage 12a. It becomes a state.

  Next, when the under cover 20 is attached to the body main body 10a, the bottom surface side of the body main body 10a is covered with the under cover 20, and the gas flow path 12 is closed. The under cover 20 is crimped and fixed to the body main body 10a by screwing or the like.

  Due to the attachment of the under cover 20, a pressing force by the under cover 20 acts on the bottom surface of the body main body 10a. Thereby, a pair of projection part 16b set to the cylindrical member 16 is press-fit in the groove part 10a1 of the inlet flow path part 12a. In addition, the pair of receiving portions 21a2 set in the inlet recess 21a presses the lower end of the strainer 15 (the lower end 16c of the cylindrical member 16), whereby the strainer 15 is pushed inward of the inlet flow passage portion 12a, The lower end of the under cover 20 is held in the pair of receiving portions 21a2.

  In such a state, the strainer 15 is fitted into the inlet channel portion 12a and is accommodated and held by the inner wall surface of the inlet channel portion 12a.

  By assembling the strainer 15, the gas passage 17 a is arranged in the middle of the gas flow in the inlet flow path portion 12 a. By flowing the gas through the gas passage 17a, the flow of the gas on the downstream side of the end wall 17, that is, the flow of the gas flowing into the measurement unit 30 can be rectified. As a result, since the flow rate variation of the gas flowing into the measurement unit 30 can be suppressed, it is possible to suppress the occurrence of a situation in which erroneous measurement of the flow rate or measurement cannot be performed.

  Moreover, since the outer peripheral shape of the strainer 15 (cylinder member 16) is set to a shape corresponding to the inner wall surface of the inlet channel portion 12a, a gap generated between the two can be eliminated. Thereby, the gas flowing through the inlet channel portion 12a flows through the gas passage 17a without flowing into the gap between the strainer 15 and the inlet channel portion 12a. As a result, the rectifying action by the strainer 15 can be appropriately obtained.

  As described above, according to the present embodiment, the strainer 15 is connected to the cylindrical member 16 having an outer peripheral shape corresponding to the inner wall surface of the inlet flow path portion 12 a and one end of the cylindrical member 16. And an end wall 17 having an opening to be a gas passage 17a. The strainer 15 is accommodated and held by the inner wall surface of the inlet channel portion 12a.

  According to this configuration, the end wall 17 including the gas passage 17 a for rectification is configured to be integrated with the cylindrical member 16. Further, since the bottom surface side of the meter body 10 is open, the strainer 15 is accommodated and held in the inlet flow passage portion 12a by fitting the cylindrical strainer 15 into the inlet flow passage portion 12a. . Therefore, the strainer 15 can be easily assembled to the inlet channel portion 12a. For this reason, a separate member for assembling and fixing is not required, and the number of parts and the number of assembling steps can be reduced. Further, since complicated work such as screwing is not required, workability is improved and the number of assembling steps can be reduced.

  In the present embodiment, the strainer 15 is fitted into the inlet channel portion 12 a so that the end wall 17 is positioned above the cylindrical member 16. At this time, the lower end of the strainer 15 (the lower end 16c of the cylindrical member 16) is held by the receiving portion 21a2 formed in the under cover 20.

  According to this configuration, the strainer 15 is held by the receiving portion 21a2, so that the strainer 15 can be prevented from dropping into the under cover 20 (inlet recess 21a). Further, since the lower end of the strainer 15 (the lower end 16c of the cylindrical member 16) is held by the two receiving portions 21a2 on the front side and the back side, the vertical position of the strainer 15 can be appropriately maintained.

  In the present embodiment, as positioning means for positioning the strainer 15 in the inlet channel portion 12a, a cylindrical boss portion 17b standing on the end wall 17 and the inlet channel portion 12a in the body main body 10a. And a convex portion arranged inside. The positioning means positions the strainer 15 in the surface direction and the direction perpendicular to the end wall 17 by fitting the boss portion 17b and the convex portion to each other.

  According to this configuration, the position and height of the strainer 15 can be appropriately positioned. Moreover, since positioning can be performed only by fitting the boss part 17b and the convex part to each other, workability can be improved.

  Furthermore, in the present embodiment, as a fixing means for fixing the strainer 15 in the inlet flow path portion 12a, a protruding portion 16b protruding outward at the peripheral edge portion of the lower end 16c of the cylindrical member 16 and the body main body 10a And a groove 10a1 set at the peripheral edge of the inlet channel 12a facing the bottom surface. This fixing means fixes the strainer 15 by fitting the protrusion 16b and the groove 10a1 to each other.

  According to this structure, when the projection part 16b and the groove part 10a1 mutually fit, the strainer 15 is fixed and generation | occurrence | production of the rattle can be suppressed.

  In the present embodiment, ribs 16b1 are set on the protrusions 16b, and a margin in the height direction of the protrusions 16b is secured by the ribs 16b1. The protrusion 16b is set so as to protrude from the groove 10a1 by the amount of the rib 16b1, and when the under cover 20 is attached, the protrusion 16b is press-fitted into the groove 10a1. Thereby, fixation of the strainer 15 is performed firmly and generation | occurrence | production of the rattling can be suppressed effectively.

  In the present embodiment, the strainer 15 is disposed only in the inlet channel portion 12a. However, the strainer 15 is disposed only in the outlet channel portion 12c or in each of the inlet channel portion 12a and the outlet channel portion 12c. May be arranged. By arranging the strainer 15 in the outlet flow path part 12c, even if pulsation occurs, it can be made the structure which is hard to receive the influence. In addition, the structure of the strainer 15 provided in the exit flow path part 12c can be made the same as that of the inlet flow path part 12a.

  The ultrasonic gas meter according to the present embodiment has been described above, but the present invention is not limited to this embodiment, and various modifications can be made within the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Meter body 10a Body main body 10a1 Groove part 11a Gas inflow port 11b Gas outflow port 12 Gas flow path 12a Inlet flow path part 12a1 Opening part 12b Intermediate flow path part 12c Outlet flow path part 15 Strainer 16 Cylindrical member 16a Opening 16b Protrusion part 16b1 Rib 17 end wall 17a gas passage 17b boss 20 undercover 21 recess 21a inlet recess 21a1 peripheral side wall 21a2 receiving part 21b intermediate recess 21c outlet recess 30 measuring unit 31 flow path case 32 ultrasonic flow sensor 33 control board

Claims (3)

A series of gas flow paths from the gas inlet to the gas outlet are formed inside, and the body body whose bottom is opened,
An under cover disposed on the bottom surface of the body body, covering the bottom surface side of the body body and closing the gas flow path;
A gas meter comprising:
A measuring unit that is arranged in the gas flow path, and is configured by assembling a sensor in a cylindrical flow path case;
A strainer that is disposed in the vicinity of the measurement unit and rectifies the flow of gas flowing in the gas flow path;
The strainer
A cylindrical member having an outer peripheral shape corresponding to the inner wall surface of the gas flow path;
An end wall provided continuously with one end of the cylindrical member and having an opening serving as a gas passage;
A gas meter, wherein the gas meter is accommodated and held by an inner wall surface of the gas flow path. The gas flow path is
An inlet channel portion communicating with the gas inlet;
An outlet channel section communicating with the gas outlet;
It is composed of an intermediate flow path portion that communicates with each of the inlet flow path portion and the outlet flow path portion and accommodates the measurement unit, and has a flow path shape that is bent into a substantially U shape.
The gas meter according to claim 1, wherein the strainer is disposed in one or both of the inlet channel portion and the outlet channel portion. The strainer is fitted into the flow path so that the end wall is positioned at the upper end of the cylindrical member,
The gas meter according to claim 2, wherein a lower end of the strainer is held by a receiving portion formed on the under cover.

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