Ultrasonic measurement instrument

Abstract

To provide an ultrasonic measurement instrument that is able to measure a flow rate, a flow speed, and a concentration of a gas containing water vapor.SOLUTION: An ultrasonic measurement instrument according to the present disclosure includes: a channel 2 in which a fluid being measured flows; a pair of ultrasonic transmitter-receivers 3, 4 arranged obliquely opposite to each other in the channel 2; and a time measurement unit 13 that measures a propagation time between the ultrasonic transmitters-receivers 3, 4; and a heat generation unit 6 disposed in contact with an external wall of the channel 2. This ultrasonic measurement instrument is able to reduce liquid droplets caused by dew condensation of water vapor of the fluid being measured.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an ultrasonic measuring instrument for measuring the flow rate, flow velocity, and concentration of a gas. [Background technology]

[0002] Conventionally, as this type of ultrasonic measuring instrument, a so-called ultrasonic flowmeter that measures the flow rate by dividing a flow path by a partition plate has been known (see, for example, Patent Document 1).

[0003] Also known is a case where the flow rate is measured when the fluid to be measured contains steam and there is a temperature difference between the steam and the partition plate (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-43015 [Patent Document 2] Patent Publication No. 2021-18129 Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional configuration, a partition plate is provided as needed to rectify the flow of the fluid to be measured, thereby making the flow velocity distribution uniform. However, if the fluid to be measured contains steam and there is a temperature difference between the steam and the flow path through which the fluid to be measured flows or the partition plate, the steam condenses on the inner wall of the flow path or the partition plate and adheres as droplets. In some cases, these droplets may remain on the propagation path of the ultrasonic waves and block the propagation path of the ultrasonic waves. Therefore, there was a problem that the ultrasonic waves from the ultrasonic transmitter / receiver on the transmitting side collide with and diffuse into droplets adhered to the inner wall of the flow path or between the partition plates, causing attenuation of the ultrasonic waves, and a phase shift occurs, causing the signals to cancel each other out, resulting in attenuation of the received signal from the ultrasonic transmitter / receiver on the receiving side. [Means for solving the problem]

[0006] An ultrasonic measuring instrument such as an ultrasonic flow meter, a flow velocity meter, or a concentration meter in the present disclosure is an ultrasonic measuring instrument that includes a flow path through which the fluid to be measured flows, a pair of ultrasonic transmitters and receivers arranged diagonally opposite each other in the flow path, and a measuring means that measures the propagation time between the ultrasonic transmitters and receivers, and that includes a heat generating part that is arranged so as to be in contact with a part of the flow path. [Effects of the Invention]

[0007] The ultrasonic measuring instruments disclosed herein, such as ultrasonic flow meters, flow velocity meters, and concentration meters, can reduce the amount of droplets remaining on the inner walls of the flow path or between the partition plates, and can prevent the ultrasonic signals emitted from the transmitting ultrasonic transmitter / receiver from being reflected or scattered by the droplets. This allows the receiving ultrasonic transmitter / receiver to receive the ultrasonic signals efficiently and stably, thereby enabling the construction of a highly accurate ultrasonic flow meter. [Brief explanation of the drawings]

[0008] [Figure 1] (a) is a cross-sectional view of the ultrasonic measuring device according to the first embodiment; (b) is a cross-sectional view of the ultrasonic measuring device according to the first embodiment taken along line X-X'; [Figure 2] 1 is a cross-sectional view of an ultrasonic transmitter / receiver according to a first embodiment; [Figure 3] 1 is a block diagram showing the configuration of an ultrasonic flowmeter according to a first embodiment. [Figure 4] FIG. 1 is a block diagram showing the configuration of an ultrasonic concentration meter according to a first embodiment. [Figure 5] (a) is a cross-sectional view of a flow path portion of an ultrasonic measuring device according to a second embodiment; (b) is a cross-sectional view of the ultrasonic measuring device according to the second embodiment taken along line X-X'; [Figure 6] (a) is a cross-sectional view of a flow path portion of an ultrasonic measuring device according to a third embodiment; (b) is a cross-sectional view of the ultrasonic measuring device according to the third embodiment taken along line X-X'; [Figure 7] 10A is a cross-sectional view of a flow path of the ultrasonic measuring device according to the fourth embodiment; FIG. 10B is a cross-sectional view of the ultrasonic measuring device according to the fourth embodiment taken along line X-X′; [Figure 8]10A is a cross-sectional view of a flow path of an ultrasonic measuring device according to a fifth embodiment; FIG. 10B is a cross-sectional view of the ultrasonic measuring device according to the fifth embodiment taken along line X-X′; [Figure 9] 10A is a cross-sectional view of a flow path of the ultrasonic measuring device according to the sixth embodiment; FIG. 10B is a cross-sectional view of the ultrasonic measuring device according to the sixth embodiment taken along line X-X′; DETAILED DESCRIPTION OF THE INVENTION

[0009] (Findings that formed the basis of this disclosure) At the time the inventors came up with the idea of ​​the present disclosure, the purpose of ultrasonic flow measurement technology was to accurately measure the flow rate of dry gases such as dry combustible gases containing methane as a main component for household use or dry air as a measured fluid. Therefore, in the industry, the challenge to achieve high-accuracy flow rate measurement was generally to rectify the flow rate of the measured fluid and efficiently propagate ultrasonic waves to the measured fluid. Under these circumstances, the inventors came up with the idea of ​​providing a partition plate in the flow path or making the cross section of the flow path rectangular and thin and flat in order to rectify the flow rate of the measured fluid.

[0010] However, if the fluid to be measured contains steam and there is a temperature difference between the steam and the partition plates, the steam condenses and adheres as droplets between the partition plates due to its surface tension. In some cases, these droplets may remain on the ultrasonic propagation path and block the path. This has led to the problem that ultrasonic waves from the ultrasonic transmitter / receiver on the transmitting side collide with and diffuse droplets adhering to the inner wall of the flow path or between the partition plates, causing attenuation of the ultrasonic waves and a phase shift that causes the signals to cancel each other out, resulting in attenuation of the received signal from the ultrasonic transmitter / receiver on the receiving side. The subject of the present disclosure was created to solve this problem.

[0011] Therefore, the present disclosure reduces the amount of droplets remaining on the inner wall of the flow path or between the partition plates, and prevents the ultrasonic signal emitted from the transmitting ultrasonic transmitter / receiver from being reflected or scattered by the droplets, thereby enabling the receiving ultrasonic transmitter / receiver to receive the ultrasonic signal efficiently and stably, thereby enabling the construction of a highly accurate ultrasonic flow meter.

[0012] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters or redundant description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art.

[0013] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0014] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to FIGS.

[0015] [1-1. Ultrasonic measuring instrument configuration] In Figure 1, the ultrasonic measuring instrument 1 is composed of ultrasonic transmitters and receivers 3 and 4 arranged diagonally opposite to a flow path 2 through which the fluid to be measured flows. The ultrasonic transmitters and receivers 3 and 4 are fixed to the flow path 2 via a sealing part 5, and are composed of a flow path part 14 arranged so that a heating part 6 contacts the outer wall of the flow path 2, and a timing part 13 that measures the propagation time between the ultrasonic transmitters and receivers 3 and 4.

[0016] [1-2. Configuration of ultrasonic transducer] In FIG. 2, the ultrasonic transmitter / receiver 3 includes an acoustic matching body 7, a piezoelectric body 8, and lead wires 11 and 12 connected to electrodes 9 and 10 of the piezoelectric body 8.

[0017] The electrode 9 of the piezoelectric body 8 and the acoustic matching body 7 are bonded together by a bonding material (not shown). As the bonding material, for example, a general adhesive such as an epoxy adhesive, a phenolic adhesive, or a cyanoacrylate adhesive can be used.

[0018] The heating element 6, which is the heat generating part, can be formed in a planar shape by, for example, arranging metal wires so as to generate heat as evenly as possible, sandwiching them from above and below with insulating films such as polyethylene terephthalate film or polyimide film, and bonding the metal wires and films together with a general adhesive such as an epoxy adhesive, a phenolic adhesive, or a cyanoacrylate adhesive, or an acrylic pressure sensitive adhesive, etc. The metal wires can also be formed by patterning metal foil using photolithography, for example.

[0019] The heating element 6 uses resistance heating, which generates heat by passing an electric current through a resistor made of metal wire or foil. All power consumed by the resistor is converted into heat, resulting in high efficiency. Simply passing an electric current through the resistor generates heat. Metal wire or foil, such as nichrome wire, stainless steel foil, or aluminum foil, can be used. Alternatively, the heating element 6 can be a planar heating element with the characteristics of a PTC (Positive Temperature Coefficient) thermistor, which increases in resistance as current flows through it. At low temperatures, PTC heaters consist of chains of conductive particles (carbon) that allow current to flow easily (low resistance). As the temperature rises, the semiconductor particles expand, breaking the chains of conductive particles and reducing the resistance of current (high resistance). Taking advantage of this characteristic, the heater is set to limit the temperature once a certain temperature is reached, resulting in excellent energy efficiency and safety.

[0020] [1-3. Flow velocity and flow meter measurement operation] Next, an example in which the ultrasonic measuring instrument of this embodiment is used as an ultrasonic flowmeter will be described with reference to Fig. 3. In Fig. 3, ultrasonic flowmeter 20 is configured such that ultrasonic transmitter / receiver 16 is disposed upstream of flow path 15 through which a fluid flows, and ultrasonic transmitter / receiver 17 is disposed diagonally opposite to the upstream side. L1 in the figure indicates the propagation path of ultrasonic waves propagating from ultrasonic transmitter / receiver 16 disposed upstream, and L2 indicates the propagation path of ultrasonic waves from ultrasonic transmitter / receiver 17 disposed downstream. The propagation time between ultrasonic transmitter / receivers 16 and 17 is measured by timer 18, and the flow velocity and flow rate are determined by calculation unit 19. Note that heat-generating parts are omitted from Fig. 3.

[0021] Let V be the flow velocity of the fluid flowing through the flow path 15, C (not shown) be the speed of the ultrasonic waves in the fluid, θ be the angle between the direction of the fluid flow and the direction of propagation of the ultrasonic pulse, and L be the propagation distance. First, when the ultrasonic transmitter / receiver 16 is used as the ultrasonic transmitter and the ultrasonic transmitter / receiver 17 is used as the ultrasonic receiver, the propagation time t1 for the ultrasonic pulse emitted from the ultrasonic transmitter / receiver 16 to reach the ultrasonic transmitter / receiver 17 is t1 = L / (C+Vcosθ) (3) It is shown as follows.

[0022] Next, the propagation time t2 for the ultrasonic pulse emitted from the ultrasonic transducer 17 to reach the ultrasonic transducer 16 is t2 = L / (C-Vcosθ) (4) It is shown as follows. Then, if we eliminate the sound speed C of the fluid from equations (3) and (4), we get V = L / 2cosθ(1 / t1-1 / t2) (5) The following formula is obtained.

[0023] If the propagation distance L and angle θ are known, the flow velocity V can be obtained by measuring the propagation times t1 and t2 using the timing unit 18. In addition, the flow rate Q can be obtained by multiplying this flow velocity V by the flow path cross-sectional area S of the flow path 15 and a correction coefficient K using the calculation unit 19. The calculation unit 19 calculates the above Q=KSV.

[0024] [1-3. Measurement operation of concentration meter] Next, an example in which the ultrasonic measuring device of this embodiment is used as a gas concentration meter will be described with reference to FIG.

[0025] FIG. 4 shows a cross-sectional schematic diagram of a gas concentration meter 37 according to an embodiment of the present invention. The gas concentration meter 37 of the present invention includes a housing 30 as a flow path having a concentration measurement space 31 for measuring the gas concentration. The shape of the concentration measurement space 31 in the housing 30 may be, for example, a rectangular parallelepiped or cylindrical. Furthermore, the concentration measurement space 31 does not necessarily have to be part of the flow path, and it does not have to be surrounded in all directions by the walls of the housing 30, as long as it is a space that can at least transmit and receive ultrasonic waves. For example, a portion of the housing 30 may be missing, and the concentration measurement space 31 may be open to the outside at the missing portion.

[0026] The gas concentration meter 37 has a pair of ultrasonic transmitters 32 and 33 arranged facing each other within a housing 30, further houses a temperature sensor 34, and is connected to a timer 35 and a calculation unit 36. When the ultrasonic transmitter / receiver 32 is used as an ultrasonic transmitter, it transmits ultrasonic waves based on the operation of the timer 35. The ultrasonic transmitter / receiver 33 functions as an ultrasonic receiver, and the ultrasonic waves transmitted from the ultrasonic transmitter / receiver 32 propagate through the fluid to be measured that fills the housing 30, and the ultrasonic transmitter / receiver 33 used as an ultrasonic receiver receives the ultrasonic waves. The timer 35 measures the propagation times t1 and t2 based on the propagation time from when the ultrasonic waves are transmitted to when they are received and a predetermined propagation distance L of the ultrasonic waves, thereby determining the propagation velocity V of the ultrasonic waves.

[0027] V = L / 2(1 / t1-1 / t2) (6) On the other hand, the propagation velocity V of the ultrasonic wave propagating through the mixed gas, which is the fluid to be measured, is also determined by the average molecular weight M, specific heat ratio γ, gas constant R, and absolute temperature T (K) of the mixed gas, as expressed in equation (7). The average molecular weight can be determined by measuring the sound velocity and temperature.

[0028] V = γ R T / M (7) Therefore, when the gas components in a mixed gas are known, the gas temperature T and propagation speed V can be measured to determine the average molecular weight M based on equation (7), and the gas concentration can be calculated from the average molecular weight M. The concentration calculation formula for a two-component ideal gas mixture consisting of gas a and gas b is given by equation (8).

[0029] Concentration of gas a (%) = M-mb / ma-mb × 100 (8) ma and mb represent the molecular weights of gas a and gas b, respectively.

[0030] [1-4. Effects, etc.] As described above, in this embodiment, the ultrasonic measuring instrument 1 is provided with a flow path 2 through which the fluid to be measured flows, a pair of ultrasonic transmitters and receivers 3 and 4 arranged diagonally opposite each other in the flow path 2, and measuring means such as a timing unit 18 that measures the propagation time between the ultrasonic transmitters and receivers 3 and 4 and a calculation unit 19, and is provided with a heat generating unit 6 arranged so as to be in contact with the outer wall of the flow path 2.

[0031] As a result, heat is transferred from the heat generating element 6 arranged in contact with the flow path 2 to the wall surface of the flow path, reducing the amount of droplets adhering to the inner wall of the flow path and preventing the ultrasonic signal emitted from the transmitting ultrasonic transmitter / receiver from being reflected or scattered by the droplets. As a result, the ultrasonic signal can be received efficiently and stably by the receiving ultrasonic transmitter / receiver, and a highly accurate ultrasonic measuring instrument can be constructed, which can be applied to ultrasonic flow meters, ultrasonic flow meters, and gas concentration meters.

[0032] (Embodiment 2) The second embodiment will be described with reference to FIG.

[0033] [2-1. Ultrasonic measuring instrument configuration] Fig. 5 is a cross-sectional view of a flow path portion of an ultrasonic measuring instrument in embodiment 2. In Fig. 5, a flow path portion 40 is composed of ultrasonic transmitters and receivers 3 and 4 arranged diagonally opposite to a flow path 2 through which a fluid to be measured flows, and the ultrasonic transmitters and receivers 3 and 4 are fixed to the flow path via a seal portion 5, and a heat generating portion 6 is arranged so as to come into contact with the inner wall of the flow path.

[0034] [2-2. Effects, etc.] As described above, this embodiment comprises a flow path 2 through which the fluid to be measured flows, a pair of ultrasonic transmitters and receivers 3 and 4 arranged diagonally opposite each other in the flow path 2, and measuring means such as a timing unit and a calculation unit that measure the propagation time between the ultrasonic transmitters and receivers 3 and 4, and the heat generating unit 6 is arranged so as to be in contact with the inner wall of the flow path 2.

[0035] As a result, the inner wall of the flow path is heated by the heating element 6 arranged in contact with the inner wall of the flow path, thereby reducing the amount of droplets adhering to the inner wall of the flow path and preventing the ultrasonic signal emitted from the transmitting ultrasonic transmitter / receiver from being reflected or scattered by the droplets. This allows the receiving ultrasonic transmitter / receiver to receive the ultrasonic signal efficiently and stably, thereby enabling the construction of a highly accurate ultrasonic measuring instrument.

[0036] (Embodiment 3) The third embodiment will be described with reference to FIG.

[0037] [3-1. Ultrasonic measuring instrument configuration] Fig. 6 is a cross-sectional view of a flow path portion of an ultrasonic measuring instrument in embodiment 3. In Fig. 6, flow path portion 41 is composed of a rectangular flow path 2 through which a fluid to be measured flows, a partition plate 42 arranged to divide flow path 2 almost equally, and ultrasonic transmitters and receivers 3 and 4 arranged diagonally opposite each other, and ultrasonic transmitters and receivers 3 and 4 are fixed to the flow path via a seal portion 5, and a heat generating portion 6 is arranged to be in contact with the outer wall of flow path 2.

[0038] [3-2. Effects, etc.] As described above, in this embodiment, the device comprises a flow path 2 through which the fluid to be measured flows, a pair of ultrasonic transmitters and receivers 3 and 4 arranged diagonally opposite each other in the flow path 2, a partition plate 42 arranged parallel to the propagation direction of the ultrasonic waves emitted from the ultrasonic transmitters and receivers, and measuring means such as a timing unit and a calculation unit that measure the propagation time between the ultrasonic transmitters and receivers 3 and 4, and a heat generating unit 6 arranged so as to be in contact with the outer wall of the flow path 2.

[0039] As a result, the inner wall of the flow path and the partition plate 42 are heated by the heating element 6 arranged in contact with the outer wall of the flow path, thereby reducing the amount of droplets adhering to the inner wall of the flow path and the partition plate 42 and preventing the ultrasonic signal emitted from the transmitting ultrasonic transmitter / receiver from being reflected or scattered by the droplets. This allows the ultrasonic signal to be received efficiently and stably by the receiving ultrasonic transmitter / receiver, making it possible to construct a highly accurate ultrasonic measuring instrument.

[0040] (Fourth embodiment) The fourth embodiment will be described with reference to FIG.

[0041] [4-1. Ultrasonic measuring instrument configuration] Fig. 7 is a cross-sectional view of a flow path portion of an ultrasonic measuring instrument in embodiment 4. In Fig. 7, a flow path portion 43 is composed of a rectangular flow path 2 through which a fluid to be measured flows, a partition plate 42 arranged to divide the flow path 2 almost equally, and ultrasonic transmitters and receivers 3 and 4 arranged diagonally opposite each other, and the ultrasonic transmitters and receivers 3 and 4 are fixed to the flow path via a seal portion 5, and a heat generating portion 6 is arranged to contact the inner wall of the flow path.

[0042] [4-2. Effects, etc.] As described above, in this embodiment, the device comprises a flow path 2 through which the fluid to be measured flows, a pair of ultrasonic transmitters and receivers 3 and 4 arranged diagonally opposite each other in the flow path, a partition plate 42 arranged parallel to the propagation direction of the ultrasonic waves emitted from the ultrasonic transmitters and receivers, and measuring means such as a timing unit and a calculation unit that measure the propagation time between the ultrasonic transmitters and receivers, and a heat generating unit 6 arranged so as to be in contact with the inner wall of the flow path 2.

[0043] As a result, the inner wall of the flow path and the partition plate 42 are heated by the heating unit 6 arranged in contact with the inner wall of the flow path, thereby reducing the amount of droplets adhering to the inner wall of the flow path and the partition plate 42 and preventing the ultrasonic signal emitted from the transmitting ultrasonic transducer from being reflected or scattered by the droplets, thereby enabling the receiving ultrasonic transducer to receive the ultrasonic signal efficiently and stably, thereby enabling the construction of a highly accurate ultrasonic measuring instrument. In addition, a similar effect can be obtained when the flow path itself is used as a heating unit, which is a method similar to this embodiment.

[0044] (Embodiment 5) The fifth embodiment will be described with reference to FIG.

[0045] [5-1. Ultrasonic measuring instrument configuration] Fig. 8 is a cross-sectional view of a flow path portion of an ultrasonic measuring instrument in embodiment 5. In Fig. 8, a flow path portion 44 is composed of a rectangular flow path 2 through which a fluid to be measured flows, a partition plate 42 arranged to divide the flow path 2 almost equally, and ultrasonic transmitters and receivers 3 and 4 arranged diagonally opposite each other, and the ultrasonic transmitters and receivers 3 and 4 are fixed to the flow path via a seal portion 5, and a heat generating portion 6 is formed on the surface of the partition plate 42.

[0046] [5-2. Effects, etc.] As described above, in this embodiment, the device comprises a flow path 2 through which the fluid to be measured flows, a pair of ultrasonic transmitters and receivers 3 and 4 arranged diagonally opposite each other in the flow path 2, a partition plate 42 arranged parallel to the propagation direction of the ultrasonic waves emitted from the ultrasonic transmitters and receivers, and measuring means such as a timing unit and a calculation unit that measure the propagation time between the ultrasonic transmitters and receivers 3 and 4, and a heat generating unit 6 formed on the surface of the partition plate 42.

[0047] This reduces the amount of droplets that adhere to the inner wall of the flow path and the partition plate 42 by the heat generating section 6 arranged in contact with the inner wall of the flow path, and prevents the ultrasonic signal emitted from the transmitting ultrasonic transmitter / receiver from being reflected or scattered by the droplets. This allows the receiving ultrasonic transmitter / receiver to receive the ultrasonic signal efficiently and stably, making it possible to construct a highly accurate ultrasonic measuring instrument.

[0048] (Embodiment 6) The sixth embodiment will be described with reference to FIG.

[0049] [6-1. Ultrasonic measuring instrument configuration] Fig. 9 is a cross-sectional view of a flow path portion of an ultrasonic measuring instrument in embodiment 6. In Fig. 9, flow path portion 45 is composed of a rectangular flow path 2 through which a fluid to be measured flows, a partition plate 46 having a heat generating function arranged so as to divide flow path 2 almost equally, and ultrasonic transmitters and receivers 3 and 4 arranged diagonally opposite each other, and ultrasonic transmitters and receivers 3 and 4 are fixed to flow path 2 via a seal portion 5.

[0050] [6-2. Effects, etc.] As described above, in this embodiment, the device comprises a flow path 2 through which the fluid to be measured flows, a pair of ultrasonic transmitters and receivers 3 and 4 arranged diagonally opposite each other in the flow path 2, a partition plate 42 arranged parallel to the propagation direction of the ultrasonic waves emitted from the ultrasonic transmitter and receiver, and measuring means such as a timing unit and a calculation unit that measure the propagation time between the ultrasonic transmitter and receiver 3 and 4, and the partition plate 46 having a heat generating function serves as the heat generating unit.

[0051] As a result, when the partition plate 46, which has a heat-generating function, is heated, the amount of droplets adhering to the partition plate is reduced, and the ultrasonic signal emitted from the transmitting ultrasonic transmitter / receiver is prevented from being reflected or scattered by the droplets. This allows the receiving ultrasonic transmitter / receiver to receive the ultrasonic signal efficiently and stably, thereby enabling the construction of a highly accurate ultrasonic measuring instrument.

[0052] In the above embodiments 1 to 6, various arrangements of the heat generating part have been explained, but it goes without saying that the key is to heat the measured fluid flowing through the flow path, and the heat generating part should be arranged so as to be in contact with part of the flow path. [Industrial Applicability]

[0053] The present disclosure is applicable to ultrasonic measuring instruments such as ultrasonic flow meters, flow velocity meters, and concentration meters that measure the flow rate, flow velocity, and concentration of gases. Specifically, the present disclosure is applicable to household flow meters, medical anesthetic gas concentration meters, hydrogen concentration meters for fuel cells, reactive gas concentration meters for semiconductor measuring devices, and flow meters. [Explanation of symbols]

[0054] 1. Ultrasonic measuring instrument 2 Flow path 3, 4 Ultrasonic Transducer 5 Seal part 6 Heating element (heating part) 13, 18, 35 Timing section 15 Flow path 16, 17 Ultrasonic transmitter / receiver 19 Arithmetic section 20 Ultrasonic flow meter 30 Case 31 Concentration measurement space 32, 33 Ultrasonic transmitter / receiver 34 Temperature Sensor 36 Arithmetic section 42 Partition 46 Partition plate (heat generating part)

Claims

1. a flow path through which a fluid to be measured flows; a pair of ultrasonic transmitters and receivers disposed opposite to each other in the flow path; a timing unit that measures a propagation time between the ultrasonic transmitter and receiver; a heat generating portion disposed so as to be in contact with a part of the flow path; Equipped with the heat generating unit is disposed so as to be in contact with the inner wall of the flow path, and is a resistance heating type that generates heat by passing an electric current through a resistor. Ultrasonic measuring instrument.

2. 2. The ultrasonic measuring instrument according to claim 1, wherein the flow path is a cylindrical shape with a rectangular cross section divided by a partition plate.

3. a flow path through which a fluid to be measured flows; a pair of ultrasonic transmitters and receivers disposed opposite to each other in the flow path; a timing unit that measures a propagation time between the ultrasonic transmitter and receiver; a heat generating portion disposed so as to be in contact with a part of the flow path; Equipped with The flow path is a cylindrical shape with a rectangular cross section divided by a partition plate, the heat generating part is arranged on the surface of the partition plate, and the heat generating part is a resistance heating type that generates heat by passing an electric current through a resistor.

4. a cylindrical flow path having a rectangular cross section through which a fluid to be measured flows; a pair of ultrasonic transducers disposed diagonally opposite each other in the flow path; a timing unit that measures a propagation time between the ultrasonic transmitter and receiver; a partition plate that divides the flow path, The ultrasonic measuring instrument has the partition plate as a heat generating part, and the heat generating part is a resistance heating type that generates heat by passing an electric current through a resistor.

5. a temperature sensor disposed inside the flow path; the propagation time measured by the timing unit; a calculation unit that calculates a gas concentration of the mixed gas in the fluid to be measured based on the temperature measured by the temperature sensor; The ultrasonic measuring instrument according to any one of claims 1 to 4, comprising:

6. 5. The ultrasonic measuring instrument according to claim 1, further comprising a calculation unit that calculates the flow velocity or flow rate of the fluid to be measured based on the propagation time measured by the timing unit.

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