Ultrasonic Flowmeter

Abstract

An object of the present invention is to provide an ultrasonic flowmeter that can easily perform the installation operation of an ultrasonic sensor. In the ultrasonic flowmeter (10) of the present disclosure, at a pair of expansion portions (71) formed by expanding two portions of a flow path (10R) laterally, an end opening (71A) that opens in the longitudinal direction of the flow path (10R), that is, the first reference direction (H1), is provided, and the end opening (71A) is closed by a cover portion (41). A sensor fixing portion (34) for fixing the ultrasonic sensor (50) from the first reference direction (H1) is provided at the pair of expansion portions (71).

Description

Technical Field

[0001] The present disclosure relates to an ultrasonic flowmeter in which one or more pairs of ultrasonic sensors are arranged opposite to each other in a direction inclined with respect to a flow path. Background Art

[0002] As a conventional ultrasonic flowmeter, there is known an ultrasonic flowmeter in which one or more pairs of branch pipes extend obliquely from a straight pipe portion having a flow path inside, and ultrasonic sensors are attached to the ends of the respective branch pipes (see, for example, Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2010-219863 (paragraphs

[0024] ,

[0025] , and Figure 1 ) Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, in the above-described conventional ultrasonic flowmeter, it is necessary to perform a difficult operation of installing the ultrasonic sensors in a direction inclined with respect to the flow path. In particular, in an ultrasonic flowmeter having multiple pairs of ultrasonic sensors, it is necessary to perform the operation of changing the orientation of the housing for each ultrasonic sensor multiple times (for example, six times in the case of a housing having three pairs of ultrasonic sensors as shown Figure 15 ), which also requires labor and time. Therefore, there is a demand for the development of an ultrasonic flowmeter that can easily perform the installation operation of the ultrasonic sensors.

[0008] Means for Solving the Problems

[0009] An ultrasonic flowmeter according to one aspect of the present invention proposed to solve the above problems includes: a housing that connects the ends of a pair of pipes in a state of being arranged in a straight line; a flow path that is formed inside the housing and communicates with the pair of pipes and extends along a first reference direction parallel to the straight line; a pair of expansion portions formed by expanding two portions in the length direction of the flow path to the side; one or more pairs of ultrasonic sensors housed in the pair of expansion portions and arranged opposite to each other in a direction inclined with respect to the flow path; a pair of end openings formed in the pair of expansion portions, opening in opposite directions in the first reference direction and blocked by a pair of lid portions; and a sensor fixing portion disposed in a portion of the pair of expansion portions that is opposite to the pair of end openings in the first reference direction and for fixing each of the ultrasonic sensors from the first reference direction. Brief Description of the Drawings

[0010] Figure 1 is a perspective view of an ultrasonic flowmeter according to an embodiment of the present disclosure.

[0011] Figure 2 is a side cross-sectional view of the ultrasonic flowmeter.

[0012] Figure 3 is a perspective view of one end side of the ultrasonic flowmeter with the relay member removed.

[0013] Figure 4 is a perspective view of the other end side of the ultrasonic flowmeter with the relay member removed.

[0014] Figure 5 is a perspective view obtained by magnifying the ultrasonic sensor and the sensor fixing portion.

[0015] FIG. 6(A) is a side view of the ultrasonic sensor, and FIG. 6(B) is a front view of the ultrasonic sensor.

[0016] FIGS. 7(A) and 7(B) are perspective views of the ultrasonic sensor.

[0017] Figure 8 is a front view of one end of the ultrasonic flowmeter with the relay member removed.

[0018] Figure 9 is a side view of the ultrasonic flowmeter installed between a pair of pipes.

[0019] Figure 10 is a perspective view of Modification 1 of the ultrasonic flowmeter.

[0020] Figure 11 is a perspective view of Modification 2 of the ultrasonic flowmeter.

[0021] Figure 12 is a perspective view of Modification 3 of the ultrasonic flowmeter.

[0022] Figure 13 is a front view of Modification 3 of the ultrasonic flowmeter.

[0023] FIG. 14(A) is a side cross-sectional view of Modification 4 of the ultrasonic flowmeter, and FIG. 14(B) is a side cross-sectional view of Modification 5 of the ultrasonic flowmeter.

[0024] Figure 15 is a perspective view of a conventional ultrasonic flowmeter.

[0025] Description of reference numerals:

[0026] 10 to 10E Ultrasonic flowmeter

[0027] 10R Flow path

[0028] 11 Housing

[0029] 20 Inner sleeve

[0030] 21 Through-hole for ultrasonic wave propagation

[0031] 22 Sleeve mounting protrusion

[0032] 30 Outer sleeve

[0033] 33 Intermediate wall portion

[0034] 33A Radiation rib

[0035] 33B Sector rib

[0036] 33C Sector opening

[0037] 34 Sensor fixing portion

[0038] 35 Sleeve fixing portion

[0039] 40 Relay member

[0040] 40P Pipe portion

[0041] 41 Cover portion

[0042] 45 Flange portion

[0043] 50 Ultrasonic sensor

[0044] 51 Sensor body

[0045] 52 Relay ring

[0046] 53 Ultrasonic transmitting and receiving surface

[0047] 60 Sensor holder

[0048] 61 Ring portion

[0049] 62 Sensor mounting protrusion

[0050] 70 Cylindrical space

[0051] 71 Expansion portion

[0052] 71A End opening

[0053] 90 Pipe

[0054] H1 First reference direction. Detailed implementation manner

[0055] Hereinafter, with reference to Figures 1 - 9 An embodiment of the ultrasonic flowmeter 10 of the present disclosure will be described. As Figure 1As shown, the housing 11 of the ultrasonic flowmeter 10 according to this embodiment is divided into a plurality of components including an outer sleeve 30, an inner sleeve 20, and a pair of relay members 40.

[0056] As Figure 3 shown, the outer sleeve 30 is formed in a cylindrical shape, and a pair of flange portions 32 project laterally from both ends thereof. Hereinafter, the direction in which the central axis J1 (see Figure 2 ) of the outer sleeve 30 extends is referred to as the first reference direction H1.

[0057] At positions where the outer surface of the outer sleeve 30 is equally divided in the circumferential direction (for example, six equal divisions), a plurality of outer surface protrusions 31 extending in a manner connecting the pair of flange portions 32 are formed. Moreover, threaded holes 31N are formed at positions near both ends from each flange portion 32 to each outer surface protrusion 31. It should be noted that an arrow-shaped mark 30M indicating the direction in which the fluid flows is marked on the outer surface of the outer sleeve 30.

[0058] The pair of flange portions 32 are cut flat between the upper pair of outer surface protrusions 31 and between the lower pair of outer surface protrusions 31 in Figure 3 . In addition, the chamber surrounded by the upper pair of outer surface protrusions 31 and the pair of flange portions 32 becomes a wiring accommodation chamber 39. A pair of cable through holes 39A penetrating the outer sleeve 30 inside and outside are formed in the wiring accommodation chamber 39. In addition, a quadrilateral frame-shaped protruding wall 39T protrudes from the opening edge of the wiring accommodation chamber 39, and a circuit unit (not shown) is installed in a state of being fitted with the frame-shaped protruding wall 39T to block the wiring accommodation chamber 39.

[0059] At both ends of the outer sleeve 30, cover fitting portions 30K are formed by stepwise expanding the inner surface. In addition, an intermediate wall portion 33 protrudes toward the central portion of the outer sleeve 30 at the intermediate portion of the outer sleeve 30. The intermediate wall portion 33 includes a plurality of (for example, six) radial ribs 33A extending from the inner surface of the outer sleeve 30 to a position close to the center, and a plurality of fan-shaped ribs 33B alternately connecting between adjacent radial ribs 33A on one end side and the other end side in the first reference direction H1. A fan-shaped opening 33C is formed between adjacent fan-shaped ribs 33B.

[0060] As Figure 4 shown, in each fan-shaped rib 33B, a sensor fixing portion 34 is provided on the surface opening toward the end portion close to the outer sleeve 30. The sensor fixing portion 34 is formed in a cylindrical shape protruding in the first reference direction H1 from both corner portions on the front end side (the central side of the outer sleeve 30) of the fan-shaped rib 33B. In addition, as Figure 4As shown, sleeve fixing portions 35 are respectively provided beside each sensor fixing portion 34 disposed on the surface of the end opening of the outer sleeve 30 on the downstream side indicated by the arrow toward the mark 30M in the sector rib 33B. The sleeve fixing portions 35 are also formed in a cylindrical shape protruding from the intermediate wall portion 33 in the first reference direction H1 in the same manner as the sensor fixing portions 34. In addition, as Figure 5 enlargedly shown in, the front end surfaces of the sensor fixing portion 34 and the sleeve fixing portion 35 are flat surfaces orthogonal to the first reference direction H1. Moreover, threaded holes 34A and 35A are formed inside the sensor fixing portion 34 and the sleeve fixing portion 35. Specifically, in the sensor fixing portion 34, a fitting hole 34B having an inner diameter larger than that of the threaded hole 34A is provided in front of the threaded hole 34A. In addition, in the sleeve fixing portion 35, no fitting hole is provided in front of the threaded hole 35A.

[0061] It should be noted that the outer sleeve 30 of the present embodiment is cylindrical, but is not limited thereto, and may also be an elliptical cylinder shape or a prism cylinder shape with a polygonal cross-section. In addition, the outer sleeve 30 may be a molded product of resin or metal (for example, a die-cast product or a casting), or a metal processed product. In addition, when the outer sleeve 30 is a molded product of resin, the outer sleeve 30 may be an insert molded product in such a manner that the threaded holes 31N, 34A, and 35A are formed by metal nuts, or the threaded hole 31N may be a simple hole and a screw with a tapered front end (so-called, wood screw) may be screwed in. Moreover, in Figure 3 and Figure 4 etc., the radial ribs 33A and the sector ribs 33B are simplified and shown in a flat plate shape, but are partially bent or lacking. Moreover, when the outer sleeve 30 is a molded product, it can be easily demolded in the first reference direction H1.

[0062] As Figure 2 shown, the inner sleeve 20 is formed in a cylindrical shape longer than the outer sleeve 30. In addition, as Figure 5 shown, sleeve mounting protrusions 22 protrude laterally from positions where the inner sleeve 20 near one end (for example, a position near the downstream end) is equally divided in the circumferential direction (for example, trisected). Each sleeve mounting protrusion 22 is formed in a triangular tabular shape and has a through hole 22A at the front end. Moreover, the inner sleeve 20 is fixed to the outer sleeve 30 by screwing a screw B4 passing through the through hole 22A into the threaded hole 35A of the sleeve fixing portion 35. In addition, the inner sleeve 20 and the outer sleeve 30 are arranged coaxially and share the aforementioned central axis J1 (refer to Figure 2 ).

[0063] As Figure 2As shown, at both ends of the inner sleeve 20, fitting portions 29 are formed by stepwise reducing the outer diameter. In addition, at positions where the circumferences of the fitting portions 29 are equally divided in the circumferential direction, ridges 29L extending in the first reference direction H1 and slightly protruding from the circumferential surface of the fitting portions 29 are formed (refer to Figure 5 ). When the fitting portion 29 is fitted with a fitting portion 43K of a relay member 40 described later, the above-mentioned ridges 29L are flattened. In addition, the inner surface of the inner sleeve 20 gradually reduces in diameter toward the portion where the sleeve mounting protrusion 22 is disposed.

[0064] It should be noted that the inner sleeve 20 is not limited to a cylindrical shape, and may also be an elliptical cylindrical shape or a prism-shaped cylinder with a polygonal cross-section. In addition, the inner sleeve 20 of the present embodiment is a resin molded product, but may also be a metal molded product or a processed product.

[0065] As Figure 2 shown, a plurality of pairs (for example, three pairs) of through holes 21 for ultrasonic wave propagation are formed in the inner sleeve 20. Each pair of through holes 21 for ultrasonic wave propagation is a circular hole having a central axis J2 that obliquely intersects the central axis J1 of the inner sleeve 20. Therefore, when viewed from the radial direction of the inner sleeve 20, the through holes 21 for ultrasonic wave propagation are formed in an elliptical shape. Specifically, the plurality of central axes J2 intersect at a point P1 that is approximately in the center in the length direction of the central axis J1. When viewed from the axial direction of the central axis J1, the plurality of central axes J2 extend in a direction that is equally divided around the central axis J1. In addition, the portions of each central axis J2 that extend outward from the inner sleeve 20 are disposed at the center between adjacent fan-shaped ribs 33B of the outer sleeve 30. Moreover, each through hole 21 for ultrasonic wave propagation opens toward a fan-shaped opening 33C of the outer sleeve 30.

[0066] As Figure 1 shown, a pair of relay members 40 connect a cover portion 41 that closes the end opening of the plugging housing 11 and a circular plate-shaped flange portion 45 that faces the cover portion 41 by means of a pipe portion 40P.

[0067] The cover portion 41 is formed in the same shape as the flange portion 32 of the outer sleeve 30, which is obtained by flatly cutting two portions in the circumferential direction of the circular plate. In addition, as Figure 2 shown, a dike portion 41D protrudes from the outer edge portion of the cover portion 41 toward the outer sleeve 30 side, and a fitting cylinder portion 42 extends from the inner edge portion of the front end surface of the dike portion 41D. Moreover, the fitting cylinder portion 42 is fitted into a cover fitting portion 30K of the outer sleeve 30, and the front end surface of the dike portion 41D overlaps with the front end surface of the outer sleeve 30. In addition, a plurality of through holes 41A are formed in the outer edge portion of the cover portion 41 including the dike portion 41D corresponding to a plurality of threaded holes 31N of the outer sleeve 30. Moreover, a screw B1 passing through the through hole 41A is fastened to the threaded hole 31N of the outer sleeve 30 to fix the relay member 40 to the outer sleeve 30.

[0068] As Figure 1 shown, the flange portion 45 of the relay member 40 is formed in a disk shape, and a portion of the outer peripheral surface of the flange portion 45 on the side opposite to the side where the wiring accommodation chamber 39 is disposed is flatly cut to form a mounting surface 45B. In addition, through holes 45A are formed at positions where the flange portion 45 is equally divided in the circumferential direction. Moreover, as Figure 9 shown, the flange portion 45 of the relay member 40 overlaps with the flange portion 91 of the pipe 90, and bolts (not shown) pass through a plurality of through holes (not shown) provided in the flange portion 91 and the plurality of through holes 45A of the flange portion 45 and are screwed with nuts. Thus, the housing 11 of the ultrasonic flowmeter 10 is fixed between a pair of pipes 90.

[0069] As Figure 2 shown, on the inner surface of the central hole 43 passing through the central portion of the relay member 40, a fitting portion 43K is formed by stepwise expanding the end portion on the cover portion 41 side. Moreover, the fitting portion 29 of the inner sleeve 20 is fitted in the fitting portion 43K, and the inner surface of the central hole 43 and the inner surface of the ultrasonic propagation through hole 21 are arranged in the same plane. In addition, the central hole 43 is slightly expanded from the fitting portion 43K to a position near the flange portion 45, and has a uniform diameter between the opening on the flange portion 45 side from there. It should be noted that the relay member 40 in the present embodiment is made of metal, but it may also be made of resin.

[0070] Regarding the structure of the housing 11, as described above. The housing 11 has the outer sleeve 30 and the inner sleeve 20 as described above, and the cylindrical space 70 between the outer sleeve 30 and the inner sleeve 20 is partitioned into one end side and the other end side by the intermediate wall portion 33. And, a plurality of pairs of ultrasonic propagation through holes 21 communicating with one end side and the other end side of the cylindrical space 70 are formed in the inner sleeve 20. Thus, one end side and the other end side of the cylindrical space 70 become a pair of expansion portions 71 expanded from the flow path 10R inside the inner sleeve 20. Moreover, a plurality of (for example, three each) ultrasonic sensors 50 are respectively installed in each of the above-mentioned expansion portions 71, and the end openings 71A of each expansion portion 71 are blocked by the cover portion 41.

[0071] Hereinafter, the structure of the ultrasonic sensor 50 and the mounting method of the ultrasonic sensor 50 to the expansion portion 71 will be described. As shown in Fig. 6(B), the ultrasonic sensor 50 includes a sensor main body 51, a relay ring 52, and a sensor holder 60. In addition, the sensor main body 51 is formed in a cylindrical shape and has an ultrasonic transmitting and receiving surface 53 bulging in a dome shape from one end surface thereof. Hereinafter, in the sensor main body 51, the relay ring 52, and the sensor holder 60, the axial direction of the sensor main body 51 is referred to as the front-rear direction, the side having the ultrasonic transmitting and receiving surface 53 is referred to as the front side, and the opposite side is referred to as the rear side.

[0072] On the side surface of the sensor body 51, a large-diameter portion 54 obtained by increasing the diameter stepwise is provided at the middle portion in the front-rear direction. In addition, the rear surface of the sensor body 51 is flat, and a cable (not shown) extends from its central portion.

[0073] The relay ring 52 is made of a member having a higher elasticity than the sensor body 51 and the sensor holder 60 and through which ultrasonic waves hardly propagate, for example. In addition, a square groove portion 52M is formed over the entire circumferential range on the inner surface of the relay ring 52. By fitting the large-diameter portion 54 of the sensor body 51 into the square groove portion 52M, the sensor body 51 and the relay ring 52 are integrally fixed. In addition, a flange portion 52F extends laterally from the rear end portion of the relay ring 52.

[0074] As shown in FIG. 7(A), the sensor holder 60 (see FIG. 6) is formed in a structure in which a pair of sensor mounting protrusion portions 62 protrude laterally from two positions in the circumferential direction of the ring portion 61 (see FIG. 6). As shown in FIG. 6(B), the ring portion 61 is formed in an annular shape having a central axis J3 inclined with respect to the first reference direction H1. On the inner surface of the ring portion 61, a small-diameter portion 61A and a large-diameter portion 61B are provided from the front side. The flange portion 52F of the relay ring 52 is fitted into the large-diameter portion 61B, and the front surface of the flange portion 52F overlaps the stepped surface between the small-diameter portion 61A and the large-diameter portion 61B. In addition, the rear surface of the flange portion 52F is located slightly rearward of the rear surface of the ring portion 61.

[0075] As shown in FIGS. 7(A) and 7(B), the pair of sensor mounting protrusion portions 62 are formed symmetrically with respect to the left and right across the ring portion 61. FIG. 6(A) shows the shape of the sensor mounting protrusion portion 62 as viewed from the arrangement direction of the pair of sensor mounting protrusion portions 62. As shown in this figure, the sensor mounting protrusion portion 62 has a first plane 62A orthogonal to the first reference direction H1, a second plane 62B coplanar with the rear surface of the ring portion 61, and a third plane 62C parallel to the first reference direction H1. The third plane 62C is also formed in the ring portion 61, and its planar shape is circular arc-shaped (see FIG. 7(B)). In addition, a threaded hole 62N is formed in the sensor mounting protrusion portion 62 so as to be orthogonal to the second plane 62B. Then, the pressing plate 63 is overlapped with each second plane 62B of each sensor mounting protrusion portion 62 and fixed respectively by a screw B2 screwed into the threaded hole 62N. A part of the pressing plate 63 overlaps the rear surface of the flange portion 52F of the relay ring 52, whereby the sensor body 51 and the relay ring 52 are fixed to the ring portion 61.

[0076] Each sensor mounting protrusion 62 has a side protrusion 64 that protrudes toward the side away from the ring portion 61. The side protrusion 64 is disposed on the side of the sensor mounting protrusion 62 that is away from the second plane 62B, and has a first plane 62A and a plane parallel to the first plane 62A on the front and back. In addition, a through hole 62U that penetrates along the first reference direction H1 is provided in the side protrusion 64, and a cylindrical engaging protrusion 62T that shares the central axis J4 with the through hole 62U protrudes from the opening edge of the through hole 62U on the first plane 62A side of the side protrusion 64. In addition, the distance between the engaging protrusions 62T of the pair of sensor mounting protrusions 62 is the same as the distance between the sensor fixing portions 34 on both sides of the fan-shaped opening 33C of the outer sleeve 30.

[0077] A plurality of ultrasonic sensors 50 are assembled to the outer sleeve 30 in a state before assembling the inner sleeve 20 and the pair of relay members 40. Specifically, for example, the outer sleeve 30 is placed on a horizontal placement surface with the arrow of the mark 30M facing downward. In this state, as Figure 8 shown, a plurality of (for example, three) ultrasonic sensors 50 are assembled in one expansion portion 71 that is open upward.

[0078] Specifically, ultrasonic sensors 50 are respectively arranged in each fan-shaped opening 33C, and a pair of engaging protrusions 62T (refer to FIG. 6) of each ultrasonic sensor 50 are engaged with the fitting holes 34B (refer to Figure 4 ) on both sides of the fan-shaped opening 33C (refer to Figure 5 ) of the sensor fixing portions 34. Moreover, screws B3 are inserted into the through holes 62U (refer to FIG. 6) of each ultrasonic sensor 50. In this state, the screws B3 are sequentially tightened by using, for example, a screwdriver, so that the plurality of ultrasonic sensors 50 are fixed to the outer sleeve 30.

[0079] Next, the unillustrated cables of the plurality of ultrasonic sensors 50 are wound in the expansion portion 71 and penetrate the fan-shaped opening 33C near the wiring accommodation chamber 39, and are led out into the wiring accommodation chamber 39 through one cable through hole 39A (refer to Figure 3 ).

[0080] Next, the cover portion 41 of one relay member 40 overlaps with the upper surface of the outer sleeve 30 and is fixed by a plurality of screws B1, thereby closing the end opening 71A of one expansion portion 71.

[0081] Next, the outer sleeve 30 is turned upside down together with one relay member 40, and the arrow of the mark 30M faces upward. In this state, in the other expansion portion 71 that is open upward, a plurality of ultrasonic sensors 50 are assembled in the same manner as in the case of one expansion portion 71. Thus, as Figure 2As shown, sensor bodies 51 of a pair of ultrasonic sensors 50 are respectively arranged on each central axis J2 and are opposed to each other.

[0082] Next, the inner sleeve 20 is inserted into the central portion of the outer sleeve 30. As Figure 5 shown, a plurality of sleeve mounting protrusions 22 of the inner sleeve 20 overlap a plurality of sleeve fixing portions 35 of the outer sleeve 30 and are fixed by screws B4.

[0083] Next, the cable of the ultrasonic sensor 50 is led out from the other cable through hole 39A into the wiring accommodation chamber 39. In addition, the cover portion 41 of the other relay member 40 overlaps and is fixed to the upper surface of the outer sleeve 30 to block the end opening 71A of the other expansion portion 71. Moreover, for a circuit unit (not shown), the cable of the ultrasonic sensor 50 in the wiring accommodation chamber 39 is connected, and then the circuit unit overlaps and is fixed to the wiring accommodation chamber 39. Thus, the assembly of the ultrasonic flowmeter 10 is completed.

[0084] When using the ultrasonic flowmeter 10, as described above, as Figure 9 shown, the ultrasonic flowmeter 10 is connected between a pair of pipes 90, and the fluid (gas) flows in the direction of the arrow of the mark 30M. Moreover, between each pair of ultrasonic sensors 50 that are opposed to each other, the difference between the propagation time of ultrasonic waves propagating from one ultrasonic sensor 50 to the other ultrasonic sensor 50 and the propagation time of ultrasonic waves propagating from the other ultrasonic sensor 50 to the one ultrasonic sensor 50 is obtained. Moreover, the flow rate is calculated based on the average value of a plurality of difference data obtained by a plurality of pairs of ultrasonic sensors 50, or the generation of eddy currents and turbulent flows is detected by the magnitude relationship between the difference data.

[0085] The ultrasonic flowmeter 10 according to the present embodiment has the following effects. That is, in the ultrasonic flowmeter 10 of the present embodiment, an end opening 71A that opens in the length direction of the flow path 10R, that is, the first reference direction H1, is provided in a pair of expansion portions 71 formed by expanding two portions of the flow path 10R laterally, and is closed by a cover portion 41. In addition, a sensor fixing portion 34 for fixing the ultrasonic sensor 50 from the first reference direction H1 is provided in the pair of expansion portions 71. Thereby, the ultrasonic sensor 50 can be installed from the axial direction (first reference direction H1) of the flow path 10R, and the installation operation of the ultrasonic sensor 50 becomes easier compared with the conventional technique of installing the ultrasonic sensor from an inclined direction with respect to the flow path. In addition, even if the ultrasonic flowmeter 10 of the present embodiment includes multiple pairs of ultrasonic sensors 50, since half of the multiple ultrasonic sensors 50 in the multiple pairs of ultrasonic sensors 50 are installed from one end side of the flow path 10R with respect to the housing 11, and the remaining half of the multiple ultrasonic sensors 50 are installed from the other end side of the flow path 10R with respect to the housing 11, the labor and time for changing the orientation of the housing 11 can be reduced.

[0086] Specifically, as Figure 15 shown, in the ultrasonic flowmeter 1 having a conventional structure in which three pairs of ultrasonic sensors (not shown) are installed, since it is necessary to assemble the ultrasonic sensors from six directions, it is necessary to change the orientation of the housing at least six times. In contrast, in the ultrasonic flowmeter 10 according to the present embodiment, as described above, it is only necessary to change the orientation of the housing 11 (specifically, the outer sleeve 30) twice, so that the labor and time for assembling the ultrasonic sensor 50 can be significantly reduced.

[0087] In addition, in the ultrasonic flowmeter 10 of the present embodiment, the cylindrical space 70 between the outer sleeve 30 and the inner sleeve 20 is partitioned into one end side and the other end side by an intermediate wall portion 33. Moreover, by forming multiple pairs of through holes 21 for ultrasonic wave propagation that communicate with one end side and the other end side of the cylindrical space 70 in the inner sleeve 20, one end side and the other end side of the cylindrical space 70 become a pair of expansion portions 71 expanded from the flow path 10R inside the inner sleeve 20. With this structure, the flow path 10R and the pair of expansion portions 71 are separated by the inner sleeve 20, preventing the generation of turbulent flow caused by the pair of expansion portions 71.

[0088] In addition, since the inner sleeve 20 is fixed to the outer sleeve 30, the installation operation of the relay member 40 with respect to the outer sleeve 30 can be easily performed. Moreover, since the ultrasonic sensor 50 is divided into a sensor main body 51 and a sensor holder 60, the shape of the sensor holder 60 can be changed according to the shape of the housing 11 to cope with it. In addition, since the flange portion 45 attached to the pipe 90 is provided integrally with the cover portion 41, the number of components can be reduced.

[0089] Moreover, the intermediate wall portion 33 that divides the cylindrical space 70 into one end side and the other end side connects the plurality of radial ribs 33A and the plurality of sector ribs 33B, and is formed in a shape that zigzags in the circumferential direction of the outer sleeve 30. Thus, when manufacturing the outer sleeve 30 as a die-cast product, demolding of the forming die can be performed along both sides in the axial direction of the outer sleeve 30, and the mold manufacturing cost can be suppressed. In addition, each through-hole 21 for ultrasonic wave propagation opens toward a sector opening 33C between adjacent sector ribs 33B in the intermediate wall portion 33. Moreover, each sensor fixing portion 34 is disposed at the opening edges on both sides of the sector opening 33C. Thus, the radial rib 33A can be used as a wall that separates the ultrasonic sensors 50 from each other.

[0090] [Other Embodiments]

[0091] (1) In the ultrasonic flowmeter 10 of the above-described embodiment, the cover portion 41 and the flange portion 45 are connected by the pipe portion 40P. In contrast, as in the ultrasonic flowmeter 10A shown in Figure 10 , it may be configured to not have the pipe portion 40P and the flange portion 45, and only have the cover portion 41V. In this case, the ultrasonic flowmeter 10A is sandwiched between the flange portions 91 (refer to Figure 9 ) of the pair of pipes 90, and a plurality of bolts are strung across and fixed to the flange portions 91 of the pair of pipes 90.

[0092] (2) Additionally, as in the ultrasonic flowmeter 10B shown in Figure 11 , a prismatic protrusion 49 may protrude from the center portion of each cover portion 41W, a through-hole communicating with the inside of the inner sleeve 20 may be provided at the center portion of the protrusion 49, and a threaded hole portion 49N may be formed in the through-hole so as to be screwed and engaged with the external threaded portion at the end of the pipe 90.

[0093] (3) The ultrasonic flowmeter 10 of the above-described embodiment includes a total of six ultrasonic sensors 50 in three pairs. In contrast, for example, as in the ultrasonic flowmeter 10C shown in Figure 12 and Figure 13 , it may be configured to include a total of 12 ultrasonic sensors 50 in six pairs. Additionally, it may be configured to include any other arbitrary number of pairs of ultrasonic sensors. Moreover, the number of ultrasonic sensors may also be one pair.

[0094] (4) The housing 11D of the ultrasonic flowmeter 10D schematically shown in Fig. 14(A) has a pair of cover portions 81 that protrude laterally in opposite directions at positions near one end and near the other end of the straight pipe portion 80 connected to a pair of pipes. The inside of the pair of cover portions 81 is formed into a pair of expansion portions 71 obtained by expanding laterally from the flow path 10R inside the straight pipe portion 80. The end openings 71A of the pair of expansion portions 71 facing the first reference direction H1 are closed by a cover body 82. In addition, sensor fixing portions 81V are respectively provided in portions of the pair of expansion portions 71 opposed to the end openings 71A, and a pair of ultrasonic sensors 50 mounted on the two sensor fixing portions 81V are opposed to each other in a direction inclined with respect to the first reference direction H1. In this ultrasonic flowmeter 10D, the ultrasonic sensors 50 can also be assembled to the housing 11D from the length direction of the flow path 10R (i.e., the first reference direction H1), achieving the same effects as a part of the ultrasonic flowmeter 10 of the above-described embodiment.

[0095] (5) The housing 11E of the ultrasonic flowmeter 10E schematically shown in Fig. 14(B) has a base pipe portion 86 having a pair of large-diameter pipe portions 84 on both sides of a small-diameter pipe portion 83. In addition, a pair of extension pipe portions 85 are fixed to the stepped surfaces of the small-diameter pipe portion 83 and the pair of large-diameter pipe portions 84 inside the base pipe portion 86, and the pair of extension pipe portions 85 extend to the outside of the large-diameter pipe portions 84. Moreover, the inside of the small-diameter pipe portion 83 and the pair of extension pipe portions 85 is formed into a flow path 10R. In addition, the pair of extension pipe portions 85 have one or more through-holes 21 for ultrasonic wave propagation communicating with the space between the large-diameter pipe portions 84 and the extension pipe portions 85. Moreover, the space between the large-diameter pipe portions 84 and the extension pipe portions 85 is formed into a pair of expansion portions 71 obtained by expanding laterally from the flow path 10R, and the end openings 71A of the pair of expansion portions 71 facing the first reference direction H1 are closed by a cover portion 41. In addition, sensor fixing portions 84V are respectively provided in portions of the pair of expansion portions 71 opposed to the end openings 71A, and a pair or multiple pairs of ultrasonic sensors 50 mounted on the two sensor fixing portions 84V are opposed to each other in a direction inclined with respect to the first reference direction H1. In such an ultrasonic flowmeter 10E, the ultrasonic sensors 50 can also be assembled to the housing 11E from the direction in which the flow path 10R extends (i.e., the first reference direction H1), achieving the same effects as a part of the ultrasonic flowmeter 10 of the above-described embodiment.

[0096] (6) In the ultrasonic flowmeter 10 of the above-described embodiment, the ultrasonic sensors 50 are fixed to the housing 11 by screws B3, but they can also be fixed by press-fitting pins, or by adhesives or vibration welding.

[0097] In the ultrasonic flowmeter 10 of the above-described embodiment, the expansion portion 71 is separated from the flow path 10R that linearly connects between the pair of pipes 90 by the inner sleeve 20, but the expansion portion 71 and the flow path 10R may not be separated.

[0098] (8)In the ultrasonic flowmeter 10 of the above-described embodiment, the plurality of ultrasonic sensors 50 are arranged at positions that equally divide the outer sleeve 30 in the circumferential direction, and the intervals between the ultrasonic sensors 50 adjacent in the circumferential direction are made uniform, but the intervals between the ultrasonic sensors 50 may not be uniform.

Claims

1. An ultrasonic flowmeter, comprising: A housing that connects the ends of a pair of pipes to each other in a state of being arranged in a straight line; A flow path formed inside the housing and communicating with the pair of pipes, and extending along a first reference direction parallel to the straight line; and A plurality of pairs of ultrasonic sensors arranged opposite to each other in a direction inclined with respect to the flow path, The ultrasonic flowmeter is characterized by comprising: A pair of expansion parts formed by expanding two parts in the length direction of the flow path to the side and accommodating the plurality of pairs of ultrasonic sensors; A pair of end openings formed in the pair of expansion parts, opening in opposite directions in the first reference direction and blocked by a pair of cover parts; and A plurality of threaded holes arranged in a part of the pair of expansion parts that is opposite to the pair of end openings in the first reference direction and used for threadedly fixing each ultrasonic sensor, Each of the threaded holes extends along the first reference direction.

2. The ultrasonic flowmeter according to claim 1, Wherein, The housing has: An outer sleeve extending along the first reference direction; An inner sleeve penetrating the central part of the outer sleeve; An intermediate wall part formed in the outer sleeve and dividing the cylindrical space between the outer sleeve and the inner sleeve into one end side and the other end side in the first reference direction; and A plurality of pairs of ultrasonic propagation through holes penetrating the inner sleeve in a direction inclined with respect to the first reference direction and communicating with the one end side and the other end side of the cylindrical space, The one end side and the other end side of the cylindrical space are formed as the pair of expansion parts obtained by expanding from the flow path inside the inner sleeve, The plurality of threaded holes are arranged in the intermediate wall part.

3. The ultrasonic flowmeter according to claim 2, Wherein, The intermediate wall part is formed as a plate shape that divides the cylindrical space in the circumferential direction and has a plurality of radial ribs arranged radially around the inner sleeve, and a plurality of sector ribs that alternately connect adjacent radial ribs between the one end side and the other end side in the first reference direction, Each of the ultrasonic propagation through holes opens facing a sector opening part between adjacent sector ribs in the intermediate wall part, Each of the threaded holes is arranged at the opening edges on both sides of the sector opening part.

4. The ultrasonic flowmeter according to claim 2 or 3, Wherein, The ultrasonic flowmeter is provided with a plurality of sleeve mounting protrusions that protrude from the inner sleeve to the side and overlap with the intermediate wall part to be fixed.

5. The ultrasonic flowmeter according to claim 2 or 3, Wherein, A flange part is integrally provided at the front end part of a pipe part extending from the inner edge part of the cover part.

6. The ultrasonic flowmeter according to claim 2 or 3, Wherein, Each of the ultrasonic sensors is arranged at a position that divides the outer sleeve into a plurality of parts in the circumferential direction.

7. The ultrasonic flowmeter according to any one of claims 1 to 3, Wherein, The ultrasonic sensor includes a sensor main body and a sensor holder. The sensor main body has a transmission / reception surface for ultrasonic waves, and the sensor holder holds the sensor main body. The sensor holder includes: a ring portion that is fixed in a state where the sensor main body is fitted therein and has a central axis inclined with respect to the first reference direction; and a sensor mounting protrusion that extends laterally from the ring portion and has a mounting hole that penetrates in the first reference direction and communicates with the threaded hole.

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