JP4990655B2 - Ultrasonic gas meter - Google Patents

Description

  The present invention relates to an ultrasonic gas meter that detects a change in ultrasonic propagation time by an ultrasonic sensor and measures a gas flow rate.

  An ultrasonic gas meter as a general household gas meter is known from Patent Document 1, for example. In general, this ultrasonic gas meter is configured as shown in FIG. 4 in order to provide compatibility with a pipe to which an existing membrane gas meter is attached.

  That is, a gas inflow passage 3 having a gas inflow port 2 and a gas outflow passage 5 having a gas outflow port 4 are provided symmetrically on the upper side of the gas meter main body 1 so as to be separated in the left-right direction. The gas inflow passage 3 and the gas outflow passage 5 are provided in parallel and penetrating in the vertical direction. The lower ends of the gas inflow passage 3 and the gas outflow passage 5 are connected to the measurement unit main body 6 of the gas meter main body 1.

  The measurement section main body 6 is provided with a measurement flow path 7 in a direction perpendicular to the gas inflow passage 3 and the gas outflow passage 5, that is, in the horizontal direction. The upstream side of the measurement flow path 7 communicates with the gas inflow passage 3 via the inflow side communication portion 8, and the downstream side of the measurement flow path 7 communicates with the gas outflow passage 5 via the outflow side communication portion 9. Yes. Furthermore, the measurement flow path 7 is provided with a rectangular tube-shaped rectifying pipe 10 having a plurality of rectifying plates 10a therein to rectify the gas. The measurement channel 7 is provided with a pair of ultrasonic sensors (not shown) opposed to each other with an angle with respect to the gas flow direction.

  The gas inflow passage 3 is provided with a partition wall 13 that partitions the upstream side and the downstream side in the left-right direction, and the partition wall 13 is provided with a communication hole 14 that communicates the upstream side and the downstream side in the left-right direction. It has been. The gas meter main body 1 is provided with a shut-off valve 15 facing the communication hole 14 in the lateral direction.

  As shown in FIG. 5, the rectangular rectifying tube 10 forming the measurement flow path 7 has two L-shaped members 16 and 17 each having an L-shaped cross section perpendicular to the gas flow direction. The cross section perpendicular to the flowing direction is coupled so as to form a rectangular tube, and a plurality of rectifying plates 10 a are supported inside the rectifying pipe 10.

In the ultrasonic gas meter configured as described above, the gas supplied from the gas supply source through the pipe flows into the gas inflow passage 3 from the gas inlet 2 and flows from the gas inflow passage 3 through the communication hole 14. It flows through the inside of the rectifying pipe 10 of the path 7. At this time, the disturbance in the gas flow velocity distribution is rectified by the rectifier tube 10. While the gas flows inside the rectifying tube 10, a change in ultrasonic propagation time is detected by an ultrasonic sensor (not shown), the gas flow rate is measured, and the integrated flow rate is instructed to an integration instruction unit (not shown). . The gas measured in the measurement channel 7 is guided to the gas outflow passage 5 and flows from the gas outlet 4 to the gas demand side through the pipe.
JP-A-2005-106726

  However, the rectifying tube 10 that forms the measurement flow path 7 of the ultrasonic gas meter described above has a structure in which two L-shaped members 16 and 17 are fitted and joined to form a rectangular rectangular tube. Accordingly, even if the squareness of the corners slightly changes due to the warping of the L-shaped members 16 and 17, the two cannot be fitted and connected, making assembly troublesome, and variation in measurement accuracy due to variations in assembly accuracy. There is a problem that may occur.

  The present invention has been made paying attention to the above circumstances, and an object thereof is to provide an ultrasonic gas meter in which a measurement flow path can be easily assembled and measurement accuracy does not vary.

According to the first aspect of the present invention, a gas inflow passage and a gas outflow passage are provided symmetrically in the gas meter main body, the gas flowing in from the gas inflow passage is guided to the measurement flow path, and an ultrasonic sensor installed in the measurement flow path is used. After detecting the change in the propagation time of the ultrasonic wave and measuring the gas flow rate, in the ultrasonic gas meter that leads to the gas outflow passage , the shape of the measurement channel in the cross section perpendicular to the gas flow direction is copied. The first member in the shape of a letter and the second member in the form of a plate that closes the U-shaped opening of the first member form a rectangular square tube with a cross section perpendicular to the gas flow direction. In the inner bottom wall surface of the first member, a plurality of fitting grooves along the gas flow direction are formed, and on the inner wall surface of the second member, a plurality of stripes along the gas flow direction are formed. A fitting groove is formed, and each of the fitting grooves of the first member is Each of the fitting grooves corresponding to the fitting grooves of the second member is provided at an interval opposite to each other, and can be inserted into the first member from the U-shaped opening of the first member. A plurality of rectifying plates, and each rectifying plate is fitted to a fitting groove provided on the inner wall surface of the first member and an inner bottom wall surface of the second member corresponding to the fitting groove. The edge portions of the respective rectifying plates are respectively supported by the joint grooves, and a plurality of rectifying plates are arranged inside the rectangular tube-shaped measurement flow path constituted by the first member and the second member. This is an ultrasonic gas meter.

According to a second aspect of the invention, the ultrasonic gas meter according to claim 1, wherein the fitting groove is the opening of the fitting groove is wide portion, a tapered portion inside the fitting groove is narrower portion When the edge of the current plate is inserted into the fitting groove, the edge of the current plate is sandwiched by the narrow portion to hold the current plate, and the distance between the current plates is increased. It is characterized by keeping constant .

According to a third aspect of the present invention, in the ultrasonic gas meter according to the first or second aspect , the first member and the second member are formed of a synthetic resin material, and an opening end surface of the first member. A plurality of positioning projections are provided integrally with each other, and positioning holes for fitting with the positioning projections are provided on both side edges of the second member joined to the opening end surface of the first member. The projection and the positioning hole are fitted, and the fitting portion is welded to join the first member and the second member .

  According to this invention, the measurement flow path is formed in a rectangular tube having a rectangular cross section by the first member having a U-shaped cross section and the second member closing the opening of the first member. As a result, the assembly can be simplified, the number of assembling steps can be reduced, the cost can be reduced, and the variation in the measurement accuracy can be eliminated without the variation in the assembly accuracy.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the basic configuration of an ultrasonic gas meter is the same as that of the prior art, and the description thereof is omitted. A measurement channel 20 installed inside the gas meter main body 1 for measuring the flow rate of gas flowing in from the gas inflow passage 3 and leading to the gas outflow passage 5 is configured as shown in FIGS.

  That is, the measurement flow path 20 includes a first member 21 having a U-shaped cross section perpendicular to the gas flow direction, and a flat plate-like second member 22 that closes the opening of the first member 21. Therefore, the cross section perpendicular to the gas flow direction is formed by a rectifying tube 23 having a rectangular tube shape.

  The first member 21 and the second member 22 are formed of, for example, a synthetic resin material. The first member 21 includes a rectangular upper plate 21a, a lower plate 21b, and a side plate 21c that connects the upper plate 21a and the lower plate 21b, and an opening 21d is formed facing the side plate 21c. Yes. The second member 22 is formed in the same rectangular shape as the side plate 21 c of the first member 21.

  The inner surface of the first member 21 on the upper plate 21a, the lower plate 21b, and the side plate 21c at both ends in the longitudinal direction, and the inner surface at the both ends in the longitudinal direction of the second member 22, A tapered surface 24 is formed so as to become thinner toward the end, and both end openings of the rectifying tube 23 are expanded.

  Furthermore, convex portions 25 and concave portions 26 are alternately provided in the width direction of the upper plate 21a and the lower plate 21b on the opening end surfaces of the first member 21, that is, the end surfaces of the upper plate 21a and the lower plate 21b. A plurality of positioning protrusions 27 are integrally provided. Concave portions 28 corresponding to the convex portions 25 and convex portions 29 corresponding to the concave portions 26 are formed on both side edges of the second member 22 at the end surfaces facing the upper plate 21 a and the lower plate 21 b of the first member 21. Are provided alternately. The recess 28 is provided with a positioning hole 30 for fitting with the positioning protrusion 27. And the 1st member 21 and the 2nd member 22 are couple | bonded by fitting the positioning protrusion 27 and the positioning hole 30, and carrying out the heat welding or ultrasonic welding of this fitting part.

  Further, a plurality of fitting grooves 31 and 32 are provided on the inner wall of the side plate 21c of the first member 21 and the inner wall of the second member 22 along the gas flow direction and at equal intervals in the vertical direction. It has been. These fitting grooves 31 and 32 have taper portions 31a and 32a having a wide opening and a narrow width inside, and the narrow width portion is formed in a rectangular U shape continuously with the taper portions 31a and 32a. Is formed. And when the edge part of the baffle plate 33 mentioned later is inserted in the fitting grooves 31 and 32, the edge part of the baffle plate 33 is clamped by the narrow part, and the space | interval of the baffle plate 33 is kept constant. Is formed. That is, the rectifying plate 33 is a rectangular thin plate-like body made of a metal material, and the side edges along the longitudinal direction are inserted into the fitting grooves 31 and 32 to be supported. Reference numeral 34 denotes an opening window to which an ultrasonic sensor (not shown) is attached.

  When assembling the rectifying pipe 23 configured in this way, one end edge portion of the rectifying plate 33 is inserted into the fitting groove 31 provided in the side plate 21 c of the first member 21. At this time, since the fitting groove 31 is formed in the taper portion 31a, the fitting groove 31 serves as a guide when the rectifying plate 33 is inserted, and workability is good when the rectifying plate 33 is inserted. Moreover, since the inside of the fitting groove 31 is formed in a narrow width portion, when the end edge portion of the rectifying plate 33 is inserted into the fitting groove 31, the end edge portion of the rectifying plate 33 is sandwiched between the narrow width portions. Thus, the current plate 33 is cantilevered.

  Next, the second member 22 is positioned in the opening 21d so as to close the opening 21d of the first member 21, and the convex portion 25 of the first member 21 and the concave portion 28 of the second member 22 are fitted. At the same time, when the convex portion 29 of the second member 22 is fitted into the concave portion 26 of the first member 21, the positioning projection 27 and the positioning hole 30 are fitted. At this time, the other edge portion of the rectifying plate 33 cantilevered by the first member 21 is inserted into the fitting groove 32 of the second member 22, but the fitting groove 32 is formed in the tapered portion 32a. Therefore, the rectifying plate 33 is easily inserted into the fitting groove 32 as a guide for inserting the rectifying plate 33, and the end edge of the rectifying plate 33 is sandwiched between the narrow portions. Become.

  According to the rectifying pipe 23 constituting the measurement flow path 20 of the ultrasonic gas meter configured as described above, the gas supplied from the gas supply source via the pipe flows into the gas inflow passage 3 from the gas inlet 2. Then, the gas flows from the gas inflow passage 3 into the measurement flow path 20. At this time, the gas is rectified into a laminar flow by the rectifying pipe 23, and while the gas flows inside the rectifying pipe 23, a change in ultrasonic propagation time is detected by an ultrasonic sensor (not shown) to measure the gas flow rate. Then, the integrated flow rate is instructed to an integration instruction unit (not shown). The gas measured in the measurement channel 20 is guided to the gas outflow passage 5 and flows from the gas outlet 4 to the gas demand side through the pipe.

  The measurement flow path 20 has a gas flow caused by a first member 21 having a U-shaped cross section perpendicular to the gas flow direction and a second member 22 that closes the opening of the first member 21. A cross section perpendicular to the direction is formed in a rectangular prismatic shape, and the first member 21 can be configured by a simple assembling operation by simply closing the opening of the first member 21 with the second member 22. Therefore, there is no variation in assembly accuracy, and variations in measurement accuracy can be eliminated. Further, the number of assembling steps can be reduced, and the cost can be reduced.

  Further, since the both sides of the rectifying plate 33 are supported by being fitted into the fitting grooves 31 and 32 inside the rectifying pipe 23, the rectifying plate 33 can be supported easily and firmly, There is also an effect that the mutual interval is maintained with high accuracy and the measurement accuracy is improved.

  The present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements over different embodiments may be combined.

The 1st Embodiment of this invention is shown, and the disassembled perspective view of the rectifier pipe which comprises a measurement flow path. The same embodiment is shown, (a) is a top view of the 1st member and the 2nd member, (b) is a side view of a rectifier tube. The same embodiment is shown, (a) is sectional drawing which follows the AA line of FIG. 2, (b) is sectional drawing which follows the BB line of FIG. The longitudinal front view of the conventional ultrasonic gas meter. The disassembled perspective view of the rectifier pipe which comprises the conventional measurement flow path.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Gas meter main body, 2 ... Gas inflow port, 3 ... Gas inflow path, 4 ... Gas outflow port, 5 ... Gas outflow passage, 20 ... Measurement flow path, 21 ... 1st member, 22 ... 2nd member, 23 ... Rectifier tube, 31, 32 ... Fitting groove, 33 ... Rectifier plate

Claims (3)

A gas inflow passage and a gas outflow passage are provided symmetrically in the gas meter body, the gas flowing in from the gas inflow passage is guided to the measurement flow path, and the ultrasonic propagation time changes by the ultrasonic sensor installed in the measurement flow path After detecting the gas flow rate and measuring the gas flow rate, in the ultrasonic gas meter leading to the gas outflow passage,
A first member having a U- shape in a cross section perpendicular to the gas flow direction in the measurement channel, and a second plate-like second member closing the U-shaped opening of the first member. The member forms a rectangular cylinder with a cross section perpendicular to the gas flow direction ,
A plurality of fitting grooves along the gas flow direction are formed on the inner bottom wall surface of the first member, and a plurality of fitting grooves along the gas flow direction are formed on the inner wall surface of the second member. Forming a mating groove, each of the fitting grooves of the first member is provided at an interval opposite to each of the fitting grooves corresponding to the fitting groove of the second member;
Furthermore, provided with a plurality of current plates that can be inserted into the first member from the U-shaped opening of the first member,
Each rectifying plate includes a fitting groove provided on the inner wall surface of the first member and a fitting groove provided on the inner bottom wall surface of the second member corresponding to the fitting groove. An ultrasonic gas meter , wherein each end edge portion is supported, and a plurality of rectifying plates are arranged inside a rectangular tube-shaped measurement flow path constituted by the first member and the second member . The fitting groove has a tapered portion in which the opening of the fitting groove is a wide portion and the inside of the fitting groove is a narrow portion, and an end edge portion of the rectifying plate is inserted into the fitting groove. when ultrasonic gas meter according to claim 1 in which the end edges of the rectifying plate holding the rectifying plate is sandwiched the narrow portion, characterized in that maintaining a distance to the current plate constant. The first member and the second member are formed of a synthetic resin material, and a plurality of positioning protrusions are integrally provided on the opening end surface of the first member, and are joined to the opening end surface of the first member. Positioning holes for fitting with the positioning projections are provided at both side edges of the second member to be fitted, the positioning projections and the positioning holes are fitted, and the fitting portions are welded to the first member. The ultrasonic gas meter according to claim 1 or 2, wherein the member and the second member are combined .

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