Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JP4341782 Abstract: To provide an ultrasonic transducer capable of performing normal measurement without being affected by moisture. A clearance 39 is formed at an interval such that moisture escapes due to its own weight even if dew condensation occurs, and an interval such that it escapes due to a negative pressure received from a fluid to be measured flowing through a measuring pipe. . The gap 39 is in communication with the transmission / reception space 41 that transmits / receives ultrasonic waves. On the outer surface of the other end 45, in order to maintain the state of the gap 39, a plurality of convex portions are disposed and formed at an equal pitch. A plurality of housing through holes 42 are formed in the inner housing 35 so as to penetrate the inner and outer surfaces. [Selected figure] Figure 2 Ultrasonic transducer [0001] The present invention relates to an ultrasonic transducer, and more particularly to an ultrasonic transducer used in an ultrasonic flowmeter for gas. [0002] The following technology is disclosed in Patent Document 1 below. In FIG. 8A, the ultrasonic flowmeter 1 includes a measurement pipe 2 in which a fluid to be measured flows at a flow velocity F. The measuring tubes 2 are provided with supporting tubes 3 04-05-2019 1 and 4 which face each other at an angle β with respect to the tube axis OO. An ultrasonic transducer 5 is fixed to the support tube 3 and an ultrasonic transducer 6 is coaxially fixed to the support tube 4. [0003] The ultrasonic flowmeter 1 emits ultrasonic waves from the ultrasonic transducer 6 in a forward direction for a predetermined time as indicated by the arrow Ua, and receives the ultrasonic waves at the ultrasonic transducer 5 as indicated by arrow Ua. It has become. The ultrasonic transducer 5 receives ultrasonic waves and then emits ultrasonic waves in the opposite direction to the flow as shown by the arrow Ub, that is, toward the ultrasonic transducer 6. The ultrasonic transducers 5 and 6 have the same structure. The ultrasonic transducers 5 and 6 alternately repeat transmission and reception of ultrasonic waves. [0004] In the section of the ultrasonic transducers 5 and 6, the time difference between the propagation time of the ultrasonic wave in the arrow Ua direction and the propagation time of the arrow Ub is a time difference proportional to the flow velocity in the arrow F direction of the fluid to be measured It has been known. Therefore, the ultrasonic flowmeter 1 obtains the flow rate obtained by performing Reynolds number correction on the flow pattern of the fluid to be measured in the above time difference, and obtains the flow rate by multiplying this flow rate by the pipe cross-sectional area of the measurement pipe 2 It can be done. [0005] In FIG. 8B, the ultrasonic transducer 5 has a substantially cylindrical shape in which an elastic body 7, an ultrasonic wave transmitting / receiving element (not shown) embedded in the elastic body 7, and a portion of the elastic body 7 adhere. And the inner side housing 8 (The ultrasonic transducer 6 is also the same, so the description here is omitted). The ultrasonic transducer 5 is fixed by inserting the inner housing 8 into the support pipe 3 formed in the measurement pipe 2 without a gap. The elastic body 7 has one end 9 of a substantially cylindrical shape, the other end 10 of a substantially cylindrical shape, and a narrow portion 11 of a small diameter located therebetween. One end 9 is fixed to the inner housing 8. At the other end 10, an ultrasonic wave transmitting / receiving element is embedded. 04-05-2019 2 [0006] A gap 12 is provided between the outer surface of the other end portion 10 and the inner surface of the inner housing 8. Further, a damping action space 13 is provided between the constricted portion 11 and the inner surface of the inner side housing 8. The gap 12 between the outer surface of the other end 10 and the inner surface of the inner housing 8 is formed in such a way that a very small space is created. Between the end face 14 of the other end 10 and the end face 15 of the inner housing 8, a seal for preventing the gap 12 from communicating with the transmission / reception space 16 in the measurement tube 2 for transmitting / receiving ultrasonic waves. A member 17 is provided. The sealing member 17 is provided to prevent moisture (liquid) from the fluid to be measured from entering the gap 12. Although the space 12 is a very small space, it is a space sufficient for water to enter. [0007] The reason why the sealing member 17 is provided is that if the elastic body 7 is encased by the water from the fluid to be measured, the elastic body 7 will be in a crosslinked state with respect to the inner side housing 8 as well. The ultrasonic wave does not propagate in the gas, but propagates to the inner housing 8 which is more easily transmitted. As a result, there is a risk that the transmission and reception of the ultrasonic wave may be disturbed to cause a measurement failure. . Patent No. 3639570 gazette [0008] By the way, in the above-mentioned prior art, since the sealing member 17 is provided between the end surface 14 of the other end 10 of the elastic body 7 and the end surface 15 of the inner housing 8, the following problems are caused. have. That is, when, for example, dew condensation or the like occurs inside the inner housing 8, the moisture can not be extracted by the presence of the sealing member 17, and as a result, transmission and reception of the ultrasonic wave is hindered. I have a point. [0009] 04-05-2019 3 If dew condensation or the like occurs on the inner side, the ultrasonic transducer 5 must be removed from the support tube 3 to remove moisture, which requires a troublesome operation. In addition, good measurement results can not be obtained until this troublesome work is done. The inventor of the present application has found that the received waveform is disturbed and normal measurement can not be performed. [0010] The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an ultrasonic transducer which can perform normal measurement without being affected by moisture. [0011] The ultrasonic transducer according to claim 1 of the present invention, which was made to solve the above problems, has a substantially cylindrical or substantially discoid end, a substantially cylindrical other end, and a position between them. Ultrasonic wave comprising: an elastic body having a small diameter neck portion, an ultrasonic wave transmitting / receiving element embedded in the elastic body, and a substantially cylindrical inner housing to which the elastic body is fixed via the one end portion It is a transducer, wherein the inner housing and the elastic body have a damping action space between the inner surface of the inner housing and the narrow portion, and between the inner surface of the inner housing and the other end. In an ultrasonic transducer having a gap, a plurality of convex portions are provided on the outer surface of the other end, the diameter of the other end is adjusted to positively form the gap, and ultrasonic waves are generated. Transmitting and receiving space in the measuring tube to transmit and receive And between said inner housing so as to communicate the said elastic member is disposed is formed, and, wherein the inner housing, is characterized in that a plurality of locations forming a housing through hole through the internal housing. [0012] According to the present invention having such a feature, even if, for example, dew condensation occurs or water from the fluid to be measured enters between the inner housing and the elastic body, the water naturally comes out. . [0013] The ultrasonic transducer according to the second aspect of the present invention is the ultrasonic transducer according to the first aspect, wherein the housing through holes are formed at four positions at equal pitches in the circumferential direction of the inner housing. It 04-05-2019 4 is characterized by being set to. [0014] According to the present invention having such a feature, the housing through hole is disposed and formed at a position that is not easily influenced by the mounting direction of the ultrasonic transducer. The housing through hole is preferably arranged and formed in consideration of, for example, the position of the screw hole when supporting and fixing the inner housing to the support pipe of the measurement pipe through which the fluid to be measured flows (for example, screw hole If there are four, place and form it so as to be located between adjacent screw holes). [0015] The ultrasonic transducer according to the third aspect of the present invention is characterized in that, in the ultrasonic transducer according to the first aspect or the second aspect, the application is gas measurement. [0016] According to the present invention having such a feature, even if water is temporarily contained in the gas, the water naturally comes out, so that it becomes an ultrasonic transducer suitable for gas measurement. [0017] According to the present invention, it is possible to provide an ultrasonic transducer which is not affected by moisture. In addition, the ultrasonic transducer according to the present invention has an effect that normal measurement can be performed. [0018] 04-05-2019 5 Hereinafter, description will be made with reference to the drawings. FIG. 1 is a view schematically showing the measurement principle of the ultrasonic flowmeter. 2 is a front view showing an embodiment of the ultrasonic transducer according to the present invention, FIG. 3 is a sectional view taken along the line AA of FIG. 2, and FIG. 4 is a perspective view of the ultrasonic transducer. [0019] In FIG. 1, an ultrasonic flowmeter 21 is for measuring gas, and includes a measurement pipe 22 through which a fluid to be measured (for example, gas) flows at a flow velocity V. The measuring tubes 22 are provided with ultrasonic transducers A and B via the support tubes 23 and 23, respectively. The ultrasonic flowmeter 21 is configured to obtain a flow rate from the difference in propagation time of ultrasonic waves transmitted and received alternately between the ultrasonic transducers A and B. The ultrasonic flowmeter 21 is not susceptible to rotational flow in the transmission and reception of ultrasonic waves, and can achieve high measurement resolution, "reflection (single reflection) method", and "propagation of the propagation time, which does not relate to the speed of sound. By adopting the difference method , it becomes possible to measure the gas flow rate with high accuracy and stability. The principle of measurement will be briefly described below. [0020] Let "Tab" be the propagation time (s) from ultrasonic transducer A to B, "Tba" be the propagation time (s) from ultrasonic transducer B to A, "L" be the propagation of ultrasonic waves The distance (m), "C" is the velocity of sound (m / s) in the measurement gas, "V" is the flow velocity of the measurement gas (m / s), "φ" is the path of the ultrasonic wave and the measurement tube 22 When it is an angle with the central axis of the conduit, when gas is flowing, it is expressed by the following equation. 04-05-2019 6 [0021] [0022] From equations (1) and (2), [0023] [0024] Assuming that the cross-sectional area of the measurement pipe 22 is A (m <2>), the flow rate Q (m <3> / h) is expressed by the following equation (4). [0025] [0026] That is, the flow velocity is obtained from the difference of the reciprocal of the ultrasonic wave propagation time (see the above equation (3)), and as a result, the flow rate can be obtained (see the above equation (4)). [0027] Next, the ultrasonic transducer 31 of the present invention corresponding to the abovementioned ultrasonic transducers A and B will be described with reference to FIGS. 2 to 4. [0028] In FIG. 2 to FIG. 4, the ultrasonic transducer 31 of the present invention comprises a housing 32 supported and fixed to the support tube 23 by screwing. The ultrasonic transducer 31 also includes an elastic body 33 housed in the housing 32 and an ultrasonic wave transmitting / receiving element 34 embedded in the elastic body 33. 04-05-2019 7 [0029] The housing 32 is manufactured by cutting a material made of, for example, stainless steel. The housing 32 has an inner housing 35 inserted into the support pipe 23, a flange 36 screwed to the support pipe 23, and an outer housing 38 exposed to the outside of the support pipe 23 to lead out the wire 37. ing. [0030] The ultrasonic transducer 31 according to the present invention is characterized by an inner housing 35, an elastic body 33 accommodated in the inner housing 35, and a gap 39 formed therebetween (see FIG. The other configuration is basically the same as the conventional one, and the detailed description will be omitted). [0031] The inner housing 35 has a substantially cylindrical shape and is formed so that the tip end portion 40 is exposed to the pipe of the measuring tube 22, that is, the transmission / reception space 41 (see FIG. 1) for transmitting and receiving ultrasonic waves. It is done. The inner housing 35 has a predetermined length, and an annular flange 36 is coupled to the proximal end. The inner surface and the outer surface of the inner housing 35 are formed to be concentric with the central axis (not shown) of the housing 32 when viewed in cross section. A plurality of housing through holes 42 are formed in such an inner housing 35 so as to penetrate the inner and outer surfaces. [0032] 04-05-2019 8 The housing through holes 42 are disposed and formed at four locations at equal pitches (90degree pitch) in the circumferential direction of the inner housing 35 (the number is an example. The number may be one or more than one). The housing through hole 42 is disposed at a position shifted by 45 degrees with respect to the screw hole 43 of the flange 36. The housing through hole 42 is formed to extend along the central axis. In the present embodiment, it is formed in an oval shape (this is an example. For example, it may be formed in a substantially rectangular shape or an elliptical shape. In addition, a plurality of circular holes may be arranged in a line. [0033] Although the inner housing 35 has a shape in which a plurality of housing through holes 42 are provided, sufficient rigidity is secured. [0034] The elastic body 33 has a substantially disc-shaped end 44, a substantially cylindrical other end 45, and a small-diameter constricted portion 46 located therebetween, and is formed into a shape as illustrated. It is done. The elastic body 33 is fixed to the inner housing 35 via the one end 44 (the fixing position in the figure is an example). The other end 45 is slightly smaller in diameter than the other end 11 (see FIG. 8B) of the conventional example. That is, the other end 45 is formed such that the distance between the outer surface of the other end 45 and the inner surface of the inner housing 35 is wider than that of the conventional example. Thus, the gap 39 is positively formed larger than the conventional example. 04-05-2019 9 [0035] The gap 39 is formed in a space in which moisture escapes due to its own weight even if dew condensation occurs, and in a space which escapes due to a negative pressure received from the fluid to be measured flowing through the measuring pipe 22. The gap 39 is in communication with the transmission / reception space 41 that transmits / receives ultrasonic waves. In the present invention, no sealing member as in the prior art is present between the end surface 47 of the other end 45 and the end surface 48 of the inner housing 35. [0036] On the outer surface of the other end portion 45, in order to maintain the state of the gap 39, a plurality of convex portions 49 are arranged and formed at an equal pitch. The convex part 49 is formed in four places by the shape used as a protrusion in this form (a shape shall be an example). The convex portion 49 is formed such that its tip is in contact with the inner surface of the inner housing 35. The other end 45 is formed in a tapered shape in a portion continuous with the constricted portion 46. It is difficult for water to stay in the tapered portion. A damping action space 50 is formed between the constricted portion 46 and the inner surface of the inner housing 35. [0037] The ultrasonic wave transmitting / receiving element 34 is configured to include a disc-like piezoelectric element 51 having a predetermined piezoelectric constant, an impedance matching layer 52, and a lead wire (not shown). The ultrasonic wave transmitting / receiving element 34 is the same as the ultrasonic wave transmitting / receiving element (not shown) of the conventional example. The ultrasonic transducer 34 is disposed such that the impedance matching layer 52 is exposed at the central position of the end face 47 of the other end 45. [0038] In the above configuration and structure, when the piezoelectric element 51 is driven by the fall of the drive pulse, it is compressed in the direction of the central axis (not shown) by the vibration system consisting of the spring force of the elastic body 33 and the mass of the other 04-05-2019 10 end 45 An expanding piezoelectric alternating strain is generated, the acoustic impedance with the external medium transmitting and receiving the ultrasonic wave is matched via the impedance matching layer 52, and the ultrasonic wave is efficiently emitted. At the same time, the other end 45 of the elastic body 33 also vibrates, and this vibration propagates to the central neck 46. This vibration is damped due to the small cross sectional area of the constricted portion 46 and the large internal friction, and the damping action by the damping action space 50, and the piezoelectric alternating strain is rapidly damped. [0039] If moisture enters the gap 39, or if moisture is generated due to condensation, the gap 39 is larger than that of the conventional example, and the plurality of housing through holes 42 allow the moisture to naturally escape. Therefore, according to the present invention, the ultrasonic transducer 31 is not affected by moisture. Since the ultrasonic transducer 31 of the present invention is not affected by moisture, it has an effect that normal measurement can be performed. This effect is described below. [0040] Fig. 5 is a block diagram of the water inclusion influence test device to see the water influence in the actual flow, Fig. 6 is a graph showing the result of the water inclusion influence test, and Fig. 7 is a diagram related to the received wave of the ultrasonic transducer. is there. [0041] In FIG. 5, the water inclusion influence test device 61 flows air of 15 m / s from the upstream of the ultrasonic flowmeter 62 through the bellows pipe 63 and the pipe 64, and pressurizes the pressure feeding tank 65 at 0.1 MPa to produce water. The flow rate is set to 0.7 to 1.0 L / min, and the apparatus is configured to look at the influence of moisture in the actual flow. Reference numeral 66 indicates a volumetric flow meter. The ultrasonic flowmeter 62 is provided with either the ultrasonic transducer 31 of the present invention or the conventional ultrasonic transducers 5 and 6 (see FIG. 8). The water inclusion influence test device 61 is configured to be a test under much more severe conditions than actual usage conditions where water flows in the lower part of the pipe 64. The ultrasonic flowmeter 62 is configured to measure the flow rate with a diameter of 50 mm (numerical values of the diameter and the like are an example). 04-05-2019 11 [0042] In the graph of FIG. 6, the ordinate represents the flow velocity (m / s) and the abscissa represents the time (s), and the ordinate of the flow velocity is omitted below 12 m / s. The solid line in the graph is the result when the ultrasonic transducer 31 of the present invention is used, and in a state of flowing air at 15 m / s, 1.0 L / min of water is enclosed at the point of arrow P1, Water supply is stopped at the point of From the graph, it can be seen that in the case of using the ultrasonic transducer 31 of the present invention, it is not affected by moisture. In other words, normal measurement can be performed. [0043] On the other hand, the broken line in the graph is the result in the case of using the ultrasonic transducers 5 and 6 of the conventional example, and in the state of flowing air of 15 m / s, the moisture is 1.0 L at the point of the arrow P3. Immediately after this, it is understood that the flow velocity drops rapidly to 0 m / s and becomes immeasurable when / min is enclosed. In addition, I tried to stop the water filling but it did not return. [0044] In FIG. 7, the steady received wave in the state of not containing water has a waveform as shown in FIG. 7 (a). On the other hand, in the case where the ultrasonic transducer 31 of the present invention is used in the state where the water is sealed, the received wave has a waveform as shown in FIG. 7 (b). However, in the case where the conventional ultrasonic transducers 5 and 6 are used in a state in which water is sealed, the received wave has a waveform as shown in FIG. 7 (c). Therefore, it is natural that the result shown in the graph of FIG. 6 is obtained. [0045] As described above with reference to FIGS. 1 to 7, according to the present invention, it is possible to provide an ultrasonic transducer 31 which is not affected by moisture. Further, the ultrasonic transducer 31 of the present invention has an effect that normal measurement can be 04-05-2019 12 performed. [0046] It goes without saying that the present invention can be variously modified without departing from the spirit of the present invention. [0047] It is a figure which shows typically the measurement principle of an ultrasonic flowmeter. It is a front view showing one embodiment of an ultrasonic transducer of the present invention. It is the sectional view on the AA line of FIG. It is a perspective view of an ultrasonic transducer. It is a block diagram of the water inclusion influence examination device for seeing the water influence in a real flow. It is a graph which shows the result of a water inclusion influence test. It is a figure which concerns on the received wave of an ultrasonic transducer. (A) is a figure which shows the ultrasonic flowmeter of a prior art example, (b) is a figure which shows the ultrasonic transducer of a prior art example. Explanation of sign [0048] Reference Signs List 21 ultrasonic flow meter 22 measurement tube 23 support tube 31 ultrasonic transducer 32 housing 33 elastic body 34 ultrasonic transducer 35 inner housing 36 flange 37 wiring 38 external housing 39 gap 40 tip 41 wave receiving space 42 housing Through hole 43 screw hole 44 one end 45 other end 46 constricted part 47, 48 end face 49 convex part 50 damping space 51 piezoelectric element 52 impedance matching layer 04-05-2019 13
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