JP2006017520A - Oscillating type measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure a compressive strength of a case for housing a sensor tube and achieve a compact constitution. <P>SOLUTION: A mass flowmeter 10 comprises a pressure-resistant case 12 made of metal, a U-shaped sensor tube insertion passage 14 formed inside the sealed pressure-resistant case 12; a U-shaped sensor tube 16 inserted in the sensor tube insertion passage 14; a shaker 18 for shaking the sensor tube 16, an inflow-side pickup 20 for detecting displacements of an inflow-side conduit 16b, and an outflow-side pickup 22 for detecting displacements of an outflow-side conduit 16c. The sensor tube insertion passage 14 is shaped correspondingly to the shape of the sensor tube 16. Since the inside diameter of an inflow-side passage 14a and an outflow-side passage 14b is set at the minimum size, it is possible to maintain the compressive strength of a case main body 12A even if it has a constitution as compact as possible. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vibration type measurement apparatus, and more particularly to a vibration type measurement apparatus configured to measure a flow rate or density by exciting a sensor tube to detect displacement of the sensor tube due to Coriolis force.

  For example, a Coriolis mass flow meter or a vibratory density meter is available as a vibratory measuring device that measures a physical quantity of a fluid by vibrating a pipeline supplied with the fluid. Hereinafter, the Coriolis type mass flow meter will be described.

  In this Coriolis type mass flow meter, a sensor tube through which a fluid to be measured passes is vibrated in a radial direction by a vibrator, and a displacement of the sensor tube due to a Coriolis force proportional to the flow rate is detected by a pickup. The vibration type density meter has the same configuration as the Coriolis type mass flow meter, and the sensor tube vibrates at a frequency corresponding to the density of the fluid to be measured.

  For example, in the case of a Coriolis type mass flow meter, as a conventional vibration type measuring device, a fluid is caused to flow through a pair of sensor tubes, and the pair of sensor tubes are brought close to and away from each other by the driving force of a vibrator (drive coil). It is configured to vibrate.

  Further, the vibrator and the pickup are composed of a magnet and a coil, and when a drive pulse or a positive / negative alternating voltage (AC signal) is input to the drive coil of the vibrator, it is attached to the sensor tube. The sensor tube is vibrated by applying an attractive force or a repulsive force to the drive magnet, and the displacement of the detection magnet attached to the vibrating sensor tube is detected by a detection signal output from the sensor coil (detector) of the pickup. It comes to detect.

  Since the Coriolis force acts in the vibration direction of the sensor tube and is opposite in the inlet side and the outlet side, the sensor tube is twisted, and the twist angle is proportional to the mass flow rate. Accordingly, a pickup (vibration sensor) for detecting vibration is provided at the twisted positions on the inlet side and the outlet side of the pair of sensor tubes, and the time difference between the output detection signals of both sensors is measured to measure the twist of the sensor tube, that is, the mass. The flow rate is being measured.

  However, when performing the flow measurement by providing the mass flow meter in a gas supply system that feeds compressed natural gas pressurized to a high pressure such as CNG (Compressed Natural Gas) used as a fuel for automobiles, for example, It is necessary to increase the pressure resistance of the sensor tube.

  However, if the thickness of the sensor tube is increased, the driving force of the vibrator that vibrates the sensor tube must be increased, and the resonance amplitude at the time of measurement decreases as the rigidity of the sensor tube increases. There is a problem that the measurement accuracy is deteriorated due to being easily influenced by disturbances, or when the flow rate is measured, the phase difference (twist angle) between the vibration sensors on the inflow side and the outflow side becomes small.

Therefore, in the conventional vibration type measuring device, by supplying the fluid to be measured into the storage case from the pressure supply hole of the sensor tube, the pressure inside and outside of the sensor tube is balanced and the pressure resistance of the sensor tube is increased. High pressure fluid can be measured without increasing it. (For example, refer to Patent Document 1).
JP-A-6-331406

In the conventional vibration type measuring apparatus, when the high-pressure fluid is measured by filling the inside of the storage case with the measured fluid as described above, since the storage case has a sealed structure, the higher the supply pressure of the measured fluid, It is necessary to increase the pressure resistance of the storage case. Therefore, in the conventional configuration in which the entire sensor tube is stored in a large space regardless of the shape of the sensor tube, the pressure receiving area of the inner wall of the storage case becomes large. For example, the fuel tank of a fuel cell vehicle has a pressure of 70 MPa. In order to ensure the pressure resistance of the storage case, it is necessary to increase the thickness of the storage case significantly as the pressure increases. The problem of increasing arises.
Therefore, an object of the present invention is to provide a vibration type measuring apparatus that solves the above problems.

  In order to solve the above problems, the present invention has the following features.

In the first aspect of the present invention, an inflow side pipe into which the fluid to be measured flows in and an outflow side pipe from which the fluid to be measured flows out are arranged in parallel, and the inflow side pipe and the outflow side pipe A sensor tube having a communication line communicating between the two;
A pressure-resistant case formed so that a passage for housing the sensor tube corresponds to the shape of the sensor tube;
Pressure supply means for supplying a part of the fluid to be measured flowing through the sensor tube to the passage and maintaining the pressure of the passage at the same pressure as the internal pressure of the sensor tube;
An inlet provided in the pressure-resistant case and communicating with an end of the inflow side conduit;
An outlet provided in the pressure-resistant case, and communicated with an end of the outflow side conduit;
A vibration exciter comprising a driving magnet attached to the communication pipe and a driving coil provided in the pressure-resistant case and driving the driving magnet in a vibration direction;
A pickup comprising a detection magnet attached to the inflow side conduit and the outflow side conduit, and a detection unit provided in the pressure-resistant case and detecting a displacement of the detection magnet;
It is characterized by having.

The invention according to claim 2
The pressure-resistant case is made of a metal lump,
The passage includes an inflow side passage that is formed by being drilled in the metal lump and into which the inflow side conduit is inserted, and an outflow side passage that is formed by being drilled in the metal lump and into which the outflow side conduit is inserted. And a connection space connecting the inflow side passage and the outflow side passage.

  The invention according to claim 3 is characterized in that an end portion of the inflow side conduit and an end portion of the outflow side conduit of the sensor tube are detachably held in the pressure-resistant case.

  According to a fourth aspect of the present invention, the pressure-resistant case has a relief portion facing the excitation direction of the drive magnet, and the relief wall has an inner wall formed at a position where it does not contact the side surface of the drive magnet. It is characterized by that.

  According to the present invention, the passage for housing the sensor tube is formed in the pressure-resistant case so as to correspond to the shape of the sensor tube, and a part of the fluid to be measured flowing through the sensor tube is supplied to the passage. Since the pressure of the sensor tube is maintained at the same pressure as the internal pressure of the sensor tube, even if the shape of the sensor tube has a bent portion, the thickness of the sensor tube has a thickness corresponding to the pressure receiving area of the passage through which the sensor tube is inserted. Since the pressure-resistant case can be manufactured, the pressure-resistant case can be reduced in size and weight as compared with the conventional case where the entire sensor tube is accommodated in a wide space.

  Moreover, since the end part of the inflow side pipe line and the end part of the outflow side pipe line of the sensor tube are detachably assembled, the assembling work can be easily performed.

  In addition, since the pressure-resistant case has a relief portion that faces the excitation direction of the drive magnet, and the relief portion has a wall portion at a position that does not contact the side surface of the drive magnet, it is driven when the sensor tube is vibrated. The magnet for use does not contact the inner wall of the pressure-resistant case, and the sensor tube can be stably vibrated.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a Coriolis mass flow meter as a first embodiment of the vibration type measuring apparatus according to the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a cross-sectional view taken along the line BB in FIG. 4 is a cross-sectional view taken along the line CC in FIG. FIG. 5 is a cross-sectional view taken along line DD in FIG.

  The vibration type measuring device can be used as a vibration type density meter and a Coriolis type mass flow meter because the mass flow rate can be obtained using the density and density of the fluid to be measured. Since the vibration type density meter and the Coriolis type mass flow meter have the same configuration, this embodiment will be described in detail when used as a mass flow meter.

  As shown in FIGS. 1 to 5, the mass flow meter 10 includes a metallic pressure-resistant case 12 made of a metal lump such as stainless steel and a U-shaped sensor formed inside the sealed pressure-resistant case 12. A tube insertion passage 14, a U-shaped sensor tube 16 inserted into the sensor tube insertion passage 14, a vibrator 18 that vibrates an intermediate portion of the curved communication line 16 a of the sensor tube 16, and vibration An inflow side pickup 20 for detecting the displacement of the inflow side pipe line 16b of the sensor tube 16 and an outflow side pickup 22 for detecting the displacement of the outflow side pipe line 16c of the vibrating sensor tube 16. The sensor tube insertion passage 14 is formed in a shape corresponding to the shape of the sensor tube 16.

  The pressure resistant case 12 includes a case main body 12A that houses the sensor tube 16 and a lid 12B that seals the upper portion of the case main body 12A. An inlet 24 into which a fluid to be measured (for example, high pressure gas such as CNG or hydrogen) flows is provided on one side of the lower side surface of the case main body 12A. An outlet 26 through which the fluid is flowed is provided.

  An inflow side fixing hole 30 into which a fixing member 28 for fixing the end of the inflow side conduit 16b of the sensor tube 16 is screwed and an outflow side conduit 16c of the sensor tube 16 are formed on the lower surface of the case body 12A. And an outflow side fixing hole 34 into which a fixing member 32 for fixing the end of the fixing member 32 is screwed. The inflow side fixing hole 30 is in communication with the inflow port 24 via the communication path 36, and the outflow side fixing hole 34 is in communication with the outflow port 26 through the communication path 38.

  Further, a closing plug 40 is screwed into the lower surface side opening of the inflow side fixing hole 30 and the outflow side fixing hole 34, and the fluid to be measured is transferred by a seal member 40a formed of an O-ring held by the closing plug 40. It is closed in an airtight state so as not to leak.

  The fixing members 28 and 32 have tapered portions 28a and 32a that press the conical C-shaped rings 48 and 50 that clamp the fixing bosses 44 and 46 fixed to the end of the inflow side pipe line 16b from the outer periphery. . The fixing bosses 44 and 46 are formed in a cylindrical shape having a diameter larger than that of the sensor tube 16. The fixing bosses 44 and 46 have flow paths 44 a and 46 a penetrating in the axial direction inside, and have axial cutouts on the outer periphery. C-shaped rings 48 and 50 are fitted. The fixing members 28 and 32 are screwed into the inflow side fixing hole 30 and the outflow side fixing hole 34, whereby the tapered portions 28a and 32a press the C-shaped rings 48 and 50 inward to reduce the diameter. The C-shaped rings 48 and 50 clamp the outer periphery of the fixing bosses 44 and 46.

  As described above, since both ends of the sensor tube 16 are detachably fixed by the fixing members 28 and 32 and the C-shaped rings 48 and 50, the assembling work is easily performed and the sensor tube 16 is taken out during the maintenance work. It is also possible.

The fixing member 28 has a central hole 28b through which the fixing boss 44 is inserted, and a through hole 28c formed around the central hole 28b. The through hole 28 c penetrates in the axial direction and communicates with a bypass passage 52 that bypasses the inflow side fixing hole 30 and the inflow side passage 14 a of the sensor tube insertion passage 14. Accordingly, the fluid to be measured that flows in from the inlet 24 flows into the sensor tube 16 from the flow path 44 a of the fixing boss 44, and a part of the fluid is inserted into the sensor tube via the through hole 28 c and the bypass passage 52 of the fixing member 28. It is supplied to the passage 14. Then, the fluid to be measured that has passed through the sensor tube 16 flows out from the flow path 46 a of the fixing boss 46 on the outflow side to the outlet 26 through the communication path 38.
The through hole 28c is also used as a tool insertion hole for inserting a tool (not shown) when the fixing member 28 is screwed.

  As a result, the internal pressure of the sensor tube 16 and the external pressure (sensor tube insertion passage 14) become the same pressure, and there is no need to increase the pressure resistance of the sensor tube 16, so the thickness of the sensor tube 16 is measured with sensitivity. It is possible to measure with a good thinness.

  The inflow-side fixing member 28 has no difference between the pressure of the inflow-side fixing hole 30 facing the lower end and the pressure of the bypass passage 52 facing the upper end, and the difference in pressure receiving area is small. The fastening force of the C-shaped ring 48 with respect to 44 can be maintained.

  The fixing member 32 on the outflow side has a center hole 32b through which the fixing boss 46 is inserted, and a tool insertion hole 32c formed around the center hole 32b. The fixing member 32 is not provided with a through hole 28c on the inflow side. A sealing member 53 made of an O-ring for sealing the outer periphery of the fixing member 32 and a sealing member 54 made of an O-ring for sealing between the central hole 32b and the fixing boss 46 are provided.

  The outflow side fixing hole 34 communicates with the sensor tube insertion passage 14 via the bypass passage 56, and the pressure of the outflow side fixing hole 34 facing the lower end and the pressure of the bypass passage 56 facing the upper end. Therefore, the fastening force of the C-shaped ring 50 to the fixing boss 46 can be maintained.

  In the sensor tube 16, an inflow side pipe line 16b into which the fluid to be measured flows in and an outflow side pipe line 16c from which the fluid to be measured flows out are arranged in parallel, and the inflow side pipe line 16b and the outflow side pipe line 16c are connected to each other. And a communication pipe line 16a communicating therewith. The sensor tube insertion passage 14 includes an inflow side passage 14a through which the inflow side conduit 16b is inserted, an outflow side passage 14b through which the outflow side conduit 16c is inserted, and a planar passage through which the communication conduit 16a is inserted. 14c (connection space).

  The inflow side passage 14a and the outflow side passage 14b are formed by making holes in a lump of stainless steel or the like. Further, the planar passage 14c is provided with an escape portion 62 that allows a swinging range of the square-shaped driving magnet 18b attached at an intermediate position of the communication conduit 16a. That is, the escape portion 62 is formed at a position where the inner wall does not contact the side surface of the drive magnet 18b.

  A driving coil 18a of the vibration exciter 18 is provided at a height position facing the driving magnet 18b, and the communication pipe 16a of the sensor tube 16 is moved in the Y direction (in FIG. 1) by electromagnetic force from the driving coil 18a. Drive in a direction perpendicular to the paper surface.

  As shown in FIG. 2, the planar passage 14 c is formed so as to open on the upper surface of the case body 12 </ b> A, and is sealed by fastening the lid 12 </ b> B to the case body 12 </ b> A with fastening bolts 58. Further, as shown in FIG. 2, the upper opening 14d of the planar passage 14c has a planar passage 14c interposed between the inflow side passage 14a and the outflow side passage 14b as viewed from above, and therefore the inflow side passage 14a. And a circular portion surrounding the outflow passage 14b, a straight portion surrounding the planar passage 14c, and a bulging portion surrounding the escape portion 62. And the peripheral part surrounding 14 d of upper openings of this sensor tube insertion channel | path 14 is airtightly sealed with the sealing member 64 formed in the shape corresponding to the outline shape of 14 d of upper openings.

  As shown in FIG. 3, between the upper ends of the inflow side conduit 16b and the outflow side conduit 16c, the support member 66 mounted inside the planar passage 14c allows the inflow side conduit 16b and the outflow side conduit. 16c is supported in a parallel state.

  As shown in FIG. 4, the inflow side pipe line 16b and the outflow side pipe line 16c are inserted along the axes of the circular inflow side path 14a and the outflow side path 14b, and are approximately at the middle position in the longitudinal direction. Are fitted with quadrangular detection magnets 20b, 22b. The inflow side passage 14a and the outflow side passage 14b are formed to have a diameter larger than the range in which the detection magnets 20b and 22b swing, and are provided so that the detection magnets 20b and 22b do not come into contact with each other during measurement. As described above, since the inner diameters of the inflow side passage 14a and the outflow side passage 14b are set to the minimum necessary sizes, the pressure resistance strength when the fluid to be measured is supplied to the inflow side passage 14a and the outflow side passage 14b. The wall thickness to ensure the minimum is also necessary. This makes it possible to maintain the pressure strength of the case main body 12A with a configuration as compact as possible.

  Furthermore, a sensor coil 20a of the inflow side pickup 20 and a sensor coil 22a of the outflow side pickup 22 are provided at the same height position as the detection magnets 20b, 22b of the case body 12A. Therefore, the phase difference between the inflow side conduit 16b and the outflow side conduit 16c of the sensor tube 16 that vibrates in the Y direction is proportional to the flow rate, and the sensor coils 20a and 22a corresponding to the displacement of the magnets 20b and 22b. As a result, a detection signal is output.

  As described above, in the mass flow meter 10, the sensor tube insertion passage 14 for housing the sensor tube 16 is formed in the pressure-resistant case 12 so as to correspond to the shape of the sensor tube 16, and the sensor tube insertion passage 14 has a sensor. Since a part of the fluid to be measured flowing through the tube 16 is supplied to keep the pressure of the sensor tube insertion passage 14 at the same pressure as the internal pressure of the sensor tube 16, the shape of the sensor tube 16 has a bent portion. Since the pressure-resistant case 12 can be manufactured with a thickness corresponding to the pressure-receiving area of the sensor tube insertion passage 14 through which the sensor tube 16 is inserted even if it has a shape, it can withstand pressure rather than storing the entire sensor tube in a wide space as in the prior art. The case 12 can be reduced in size and weight.

  In the mass flow meter 10, the vibrator 18 is driven by a flow measurement control circuit (not shown) at the time of flow measurement, and the sensor tube has a period and amplitude according to the vibration characteristic (natural frequency) of the sensor tube 16. The 16 communication pipes 16a are vibrated in the Y direction.

  Thus, when a fluid flows through the vibrating sensor tube 16, a Coriolis force having a magnitude corresponding to the flow rate is generated. For this reason, an operation delay occurs between the inflow side and the outflow side of the sensor tube 16, thereby causing a phase difference in output signals between the inflow side pickup 20 and the outflow side pickup 22.

  Since the phase difference between the inflow side output signal and the outflow side output signal is proportional to the flow rate, the flow rate measurement control circuit calculates the flow rate based on the phase difference. Therefore, when the displacement of the sensor tube 16 is detected by the inflow side pickup 20 and the outflow side pickup 22, the flow rate measurement control circuit converts the phase difference accompanying the vibration of the sensor tube 16 into a mass flow rate.

FIG. 6 is a longitudinal sectional view showing a modification of the sensor tube mounting structure. In FIG. 6, the same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.
As shown in FIG. 6, the fixing bosses 44, 46 have male screw portions 44 b, 46 b that protrude downward through the central holes 28 a, 32 a of the fixing members 28, 32. A nut 70 is screwed onto 44b and 46b. Therefore, since the fixing bosses 44 and 46 can be fixed to the fixing members 28 and 32 by tightening the nut 70, the C-shaped rings 48 and 50 of the above embodiment can be eliminated.

Here, Example 2 will be described.
FIG. 7 is a longitudinal sectional view of Embodiment 2 of the present invention. FIG. 8 is an enlarged longitudinal sectional view showing the sensor tube fixing structure of the second embodiment. FIG. 9 is a cross-sectional view taken along line EE in FIG. FIG. 10 is a cross-sectional view taken along line FF in FIG. FIG. 11 is a transverse sectional view taken along the line GG in FIG. 12 is a cross-sectional view taken along the line HH in FIG. FIG. 13 is a transverse sectional view taken along the line II in FIG. 7 to 13, the same parts as those in the above embodiment are designated by the same reference numerals, and the description thereof is omitted.

  As shown in FIGS. 7 to 13, the mass flow meter 80 includes a metallic pressure resistant case 82 made of stainless steel and a pair of sensor tube insertion passages 84 formed inside the sealed pressure resistant case 82. 85, a pair of sensor tubes 86 and 87 inserted into the pair of sensor tube insertion passages 84 and 85, respectively, and a pair for exciting the intermediate portions of the curved communication pipes 86a and 87a of the sensor tubes 86 and 87. A pair of inflow side pickups 20 that detect displacement of the inflow side pipes 86b and 87b of the vibrating sensor tubes 86 and 87, and outflow side pipes 86c and 87c of the vibrating sensor tubes 86 and 87. And a pair of outflow side pickups 22 for detecting the displacement of. The sensor tube insertion passages 84 and 85 are formed in a U shape corresponding to the shape of the sensor tubes 86 and 87.

  The pressure-resistant case 82 includes a case main body 82A that houses the sensor tubes 86 and 87, and a lid 82B that seals the upper portion of the case main body 82A. An inlet 24 into which a fluid to be measured (for example, high-pressure gas such as CNG or hydrogen) flows is provided on one side of the lower side surface of the case main body 82A. An outlet 26 through which the fluid is flowed is provided.

  Further, on the lower surface of the case main body 82A, a pair of inflow side fixing holes 30 into which the fixing members 28 for fixing the end portions of the inflow side conduits 86b, 87b of the sensor tubes 86, 87 are screwed, and the sensor tube 86 are provided. , 87 are provided with a pair of outflow side fixing holes 34 into which fixing members 32 for fixing the ends of the outflow side pipes 86c, 87c are screwed. The pair of inflow side fixing holes 30 communicates with the inflow port 24 via the communication path 36, and the pair of outflow side fixing holes 34 communicates with the outflow port 26 via the communication path 38.

  The fixing members 28 and 32 screwed into the inflow side fixing hole 30 and the outflow side fixing hole 34 are connected to the fixing bosses 44 and 46 from the outer periphery via the C-shaped rings 48 and 50 as in the first embodiment. It is the structure clamped. As described above, since both ends of the sensor tubes 86 and 87 are detachably fixed by the fixing members 28 and 32 and the C-shaped rings 48 and 50, the assembling work is easily performed and the sensor tube 86 is used during the maintenance work. , 87 can be taken out.

  Similarly to the first embodiment, the inflow side fixing hole 30 and the outflow side fixing hole 34 communicate with the sensor tube insertion passages 84 and 85 through the bypass passages 52 and 56. As a result, the pressure inside the sensor tubes 86 and 87 is the same as the pressure outside (sensor tube insertion passages 84 and 85), and there is no need to increase the pressure resistance of the sensor tubes 86 and 87. , 87 can be made thin with good measurement sensitivity.

  Similarly to the first embodiment, the fixing members 28 and 32 have no difference in pressure acting on the lower end and the upper end, and the difference in pressure receiving area between the both ends is small. The fastening force of 48, 50 can be maintained.

  The planar passages 84c and 85c of the sensor tube insertion passages 84 and 85 are formed so as to open on the upper surface of the case main body 82A, and are sealed when the lid 82B is fastened to the case main body 12A by the fastening bolt 58. . Further, as shown in FIG. 9, the upper openings 84d and 85d of the planar passages 84c and 85c are formed between the planar passages 84c and 85b between the inflow side passages 84a and 85a and the outflow side passages 84b and 85b as viewed from above. Since 85c is interposed, it has a circular portion surrounding the inflow side passages 84a and 85a and the outflow side passages 84b and 84b, a straight portion surrounding the planar passages 84c and 85c, and a bulging portion surrounding the escape portion 62. The peripheral portions surrounding the upper openings 84d and 85d of the sensor tube insertion passages 84 and 85 are hermetically sealed by a pair of seal members 64 formed in a shape corresponding to the contour shape of the upper openings 84d and 85d.

  As shown in FIG. 10, the sensor tubes 86 and 87 are support members mounted inside the planar passages 84 c and 85 c between the upper ends of the inflow side conduits 86 b and 87 b and the outflow side conduits 86 c and 87 c. 66, the inflow side conduits 86b and 87b and the outflow side conduits 86c and 87c are supported in a parallel state.

  As shown in FIG. 11, the inflow side conduits 86b and 87b and the outflow side conduits 86c and 87c are inserted along the axes of the circular inflow passages 84a and 85a and the outflow passages 84b and 85b. The quadrangular detection magnets 20b and 22b are attached at substantially intermediate positions in the longitudinal direction. The inflow side passages 84a and 85a and the outflow side passages 84b and 85b are formed so as to have a larger diameter than the range in which the detection magnets 20b and 22b swing, and are provided so that the detection magnets 20b and 22b do not come into contact during measurement. It has been. In this way, since the inner diameters of the inflow side passages 84a and 85a and the outflow side passages 84b and 85b are set to the minimum necessary size, the fluid to be measured is the inflow side passages 84a and 85a and the outflow side passages 84b and 85b. The wall thickness required to ensure the pressure strength when supplied to the container is also minimal. This makes it possible to maintain the pressure resistance of the case main body 82A with a compact size as much as possible.

  As shown in FIG. 12, the sensor coil 20a of the inflow side pickup 20 and the sensor coil 22a of the outflow side pickup 22 are provided at the same height position as the detection magnets 20b and 22b of the case main body 82A. Therefore, the phase difference between the inflow side pipes 86b and 87b and the outflow side pipes 86c and 87c of the sensor tubes 86 and 87 that vibrate in the Y direction is proportional to the flow rate, and corresponds to the displacement of the magnets 20b and 22b. Detection signals are output by the sensor coils 20a and 22a.

  As shown in FIG. 12, the flat passages 84c and 85c of the sensor tube insertion passages 84 and 85 allow the swing range of the square drive magnet 18b attached to the intermediate position of the communication conduits 86a and 87a. An escape portion 62 is provided. Further, the drive coils 18a of the pair of vibrators 18 are provided symmetrically in the Y direction at the height positions facing the pair of drive magnets 18b, and the sensor tubes 86, 87 communication pipes 86a and 87a are driven in the Y direction.

  As shown in FIG. 13, the pair of inflow side fixing holes 30 communicate with each other via a communication hole 90, and the communication hole 90 communicates with the inflow port 24 via a communication path 36. Further, the pair of outflow side fixing holes 34 are communicated with each other via a communication hole 92, and the communication hole 92 is communicated with the outlet 26 via a communication path 38.

  As described above, in the mass flow meter 80, the sensor tube insertion passages 84 and 85 for housing the sensor tubes 86 and 87 in the pressure-resistant case 82 are formed so as to correspond to the shape of the sensor tubes 86 and 87. A part of the fluid to be measured flowing through the sensor tubes 86 and 87 is supplied to the tube insertion passages 84 and 85 so that the pressure in the sensor tube insertion passages 84 and 85 is kept the same as the internal pressure of the sensor tubes 86 and 87. Therefore, even if the shape of the sensor tubes 86 and 87 has a bent portion, the pressure resistant case 82 is formed with a thickness corresponding to the pressure receiving area of the sensor tube insertion passages 84 and 85 through which the sensor tubes 86 and 87 are inserted. Since it can be manufactured, the pressure-resistant case 82 can be made smaller and lighter than the conventional case where the entire sensor tube is stored in a wide space. It becomes possible.

  Further, in the mass flow meter 80, at the time of flow rate measurement, a pair of vibrators 18 are driven by a flow rate measurement control circuit (not shown), and a cycle according to the vibration characteristics (natural frequency) of the sensor tubes 86 and 87, The communication pipes 86a and 87a of the sensor tubes 86 and 87 are vibrated in the Y direction with an amplitude.

  Thus, when a fluid flows through the vibrating sensor tubes 86 and 87, a Coriolis force having a magnitude corresponding to the flow rate is generated. Therefore, an operation delay occurs between the inflow side and the outflow side of the sensor tubes 86 and 87, thereby causing a phase difference in output signals between the inflow side pickup 20 and the outflow side pickup 22.

  Since the phase difference between the inflow side output signal and the outflow side output signal is proportional to the flow rate, the flow rate measurement control circuit calculates the flow rate based on the phase difference. Therefore, when the displacement of the sensor tubes 86 and 87 is detected by the inflow side pickup 20 and the outflow side pickup 22, the flow rate measurement control circuit converts the phase difference accompanying the vibration of the sensor tubes 86 and 87 into a mass flow rate.

  In the above embodiment, the case where the flow rate is measured using a combustible gas such as CNG or hydrogen gas as the fluid to be measured is used as an example. However, the present invention is not limited to this, and the present invention is also applicable to measuring other high-pressure fluids. Of course you can.

It is a longitudinal cross-sectional view of the Coriolis type mass flow meter as Example 1 of the vibration type measuring apparatus according to the present invention. It is a cross-sectional view which follows the AA line in FIG. It is a cross-sectional view which follows the BB line in FIG. It is a cross-sectional view which follows the CC line in FIG. It is a cross-sectional view which follows the DD line | wire in FIG. It is a longitudinal cross-sectional view which shows the modification of a sensor tube attachment structure. It is a longitudinal cross-sectional view of Example 2 of this invention. It is a longitudinal cross-sectional view which expands and shows the sensor tube fixing structure of Example 2. FIG. 9 is a transverse sectional view taken along the line EE in FIG. 7. FIG. 8 is a transverse sectional view taken along line FF in FIG. 7. It is a cross-sectional view which follows the GG line in FIG. It is a cross-sectional view which follows the HH line in FIG. FIG. 8 is a transverse sectional view taken along line II in FIG.

Explanation of symbols

10,80 Mass flow meter (corresponding to vibration type measuring device)
12, 82 Pressure-resistant case 12A, 82A Case body 14, 84, 85 Sensor tube insertion passage (corresponding to the passage of claim 1)
16, 86, 87 Sensor tube 18 Exciter 20 Inlet pickup 22 Outlet pickup 24 Inlet 26 Outlet 28, 32 Fixing member 30 Inlet fixing hole 34 Outlet fixing hole 36, 38, 90, 92 Passage 44, 46 Fixing boss 48, 50 C-shaped ring 56, 52 Bypass passage 62 Escape part (
66 Support member 70 Nut

Claims (4)

An inflow side pipe into which the fluid to be measured flows in and an outflow side pipe from which the fluid to be measured flows out are arranged in parallel, and communicate with each other between the inflow side pipe and the outflow side pipe A sensor tube having
A pressure-resistant case formed so that a passage for housing the sensor tube corresponds to the shape of the sensor tube;
Pressure supply means for supplying a part of the fluid to be measured flowing through the sensor tube to the passage and maintaining the pressure of the passage at the same pressure as the internal pressure of the sensor tube;
An inlet provided in the pressure-resistant case and communicating with an end of the inflow side conduit;
An outlet provided in the pressure-resistant case, and communicated with an end of the outflow side conduit;
A vibration exciter comprising a driving magnet attached to the communication pipe and a driving coil provided in the pressure-resistant case and driving the driving magnet in a vibration direction;
A pickup comprising a detection magnet attached to the inflow side conduit and the outflow side conduit, and a detection unit provided in the pressure-resistant case and detecting a displacement of the detection magnet;
A vibration type measuring apparatus comprising: The pressure-resistant case is made of a metal lump,
The passage includes an inflow side passage that is formed by being drilled in the metal lump and into which the inflow side conduit is inserted, and an outflow side passage that is formed by being drilled in the metal lump and into which the outflow side conduit is inserted. And a connection space connecting the inflow side passage and the outflow side passage.   2. The vibration type measuring apparatus according to claim 1, wherein the sensor tube is detachably held at the pressure-resistant case at an end portion of the inflow side conduit and an end portion of the outflow side conduit.   The said pressure | voltage resistant case has an escape part which opposes the excitation direction of the said drive magnet, and this escape part has the inner wall formed in the position which does not contact the side surface of the said drive magnet. The vibration type measuring apparatus described.

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