JPH02136715A - Coriolis force straight pipe mass flowmeter - Google Patents

Abstract

PURPOSE:To exactly measure the mass flow rate of a liquid by measuring a deflection generated by Coriolis force, generated at the time when a fluid flows in a measuring straight pipe to which a rotational vibration is given by a vibration supporting part. CONSTITUTION:A measuring straight pipe 21 of some length running along the center line XX of an external frame 20 is arranged by fixing inlet and outlet pipe parts 24, 25 of its end parts to each opposed side wall of the frame 20. Also, this straight pipe 21 is supported so that the movement in the axial direction and the angle variation of the axis can be executed freely by a vibration supporting part 22 which vibrates freely in the vertical direction against the frame 20, and a fixing and supporting part 23 fixed to the frame 20, respectively. On both sides of the outside of its supporting parts 22, 23, coil-like pipe parts 31, 32 are provided, and cope with the variation of pipe length between the supporting parts 22, 23 by the variation of a curvature of the pipe parts 31, 32. Also, compensating straight pipes 33, 34 of the same material and dimension as those of the straight pipe 21 are arranged on both sides of the straight pipe 21 in parallel, and based on them as a reference, a deflection measuring part 50 is provided on about the center part of the supporting part 22, 23, and the deflection quantum by Coriolis force of the straight pipe 21 in which a fluid flows is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is useful in the field of handling liquid fluids such as oil and fat where contact with outside air is not preferred, or in the field of manufacturing industry that handles fluids. Although the present invention is intended for use in high-precision Coriolis mass flowmeters that are indispensable when measuring flow rate and precisely controlling the flow rate of the fluid, the present invention is not necessarily limited to such fields. It is not a single-phase liquid or gas, or a liquid and a gas, or a gas and a small amount of solid, which are expected to be widely used in the semiconductor industry, the petroleum industry in the advanced technology field, the biological industry, etc. It is used to accurately measure the mass flow rate of a fluid such as a two-phase flow in which gas and mist or minute solids are mixed, and to automatically control the flow rate based on this. The present invention relates to a Coriolika mass flow meter that has a simple structure and is easy to install, and therefore can be expected to be used in modern plants in many fields.

Recently, when a fluid (mainly liquid) flows through a rotating or rotationally vibrating flow pipe, the flow pipe deflects to receive Coriolis, and this deflection is proportional to the mass flow rate. Coriolis mass flowmeter has been developed, but
A typical one has a structure as shown in FIG. 5 of the accompanying drawings. That is, this mass flow meter 10 consists of a tubular main body 10° having an inlet pipe part 1 and an outlet pipe part 2 so as to be connected to the middle of the main pipe. It has a linear axis X-X connecting the centers of the inlet pipe part 1 and the outlet pipe part 2, and in order to cause the flow path to bend at 10 degrees due to the Coriolis force, An inverted U-shaped flow path tube 3 is connected at each free end at a right angle to the axis X-x of the main body 10°, and an appropriate The fluid whose mass flow rate is to be measured is subjected to rotational vibration with the axis of rotation x-X of the main body at 10 degrees by the means.
From the main pipe to the main body 1G, from the inlet pipe part 1 to the flow pipe 3
If this is branched off to the outlet pipe section 2 and returned to the main pipe again from the outlet pipe section 2, Coriolica will be generated in the straight section of the flow pipe section 3, and this will cause deflection of the flow pipe section 3. is proportional to the flow rate of the fluid flowing inside the flow path pipe 3, so
By measuring this deflection, the flow rate can be measured. In this case, in order to facilitate the measurement of the deflection of the flow pipe 3, parallel to the flow pipe 3,
Similarly, an inverted U-shaped flow pipe 4 having the same geometrical structure is provided, and each free end of the flow pipe 4 is similarly connected to the main body 100, and each flow pipe is connected to the main body 100. The bent portions of the channel pipes 3.4 are interconnected by a drive mechanism 5, which drives the channel pipes 3.4 in mutually opposite reciprocating directions at right angles to their planes. Give rotational vibration. By doing this, the portions of the linear portions of each flow pipe 3.4 that are farthest from the axis x-x of the main body 10° are vibrated in opposite directions, so that both flow pipes Taking advantage of the fact that the deflections in points 3 and 4 point in opposite directions,
Attach a measuring device 6 to this location, and with this measuring device 6,
By measuring the distance between the two pipes 3 and 4, the flow rate can be determined from the measured value of this zero distance.

However, in order to improve the accuracy of this type of conventional mass flowmeter using Coriolis, it is necessary to lengthen the straight section of the flow pipe 3.
, 4 not only requires a large space extending from the main pipe, but also increases the length of the flow pipe 3.
．． 4 is a cantilever beam that is materially fixed and supported with respect to the main body 10°, and the root portion, which is the connection part of the flow pipes 3 and 4 to the main body 10°, always has reciprocating motion. Because of the added stress caused by this, problems with fatigue strength and lifespan also arise. Furthermore, although flow path pipes 3 and 4 have the same geometric structure, depending on the flow path distribution within the main pipe, the same flow rate may not necessarily flow, and the sensitivity of deflection measurement may be affected. In order to increase the deflection, the deflection is measured by installing the deflection measuring device 6 at the straight part of the flow pipe 3.4 that is farthest from the axis X-X of the main body at 10 degrees. 3.4 may be affected by the curved portion.

In this way, in order to measure the deflection due to the Coriolis force, the conventionally known Coriolis mass flowmeter has a circular tube in addition to the inverted U-shaped flow tubes 3 and 4. These flow channels for measuring deflection are often connected to the main body 10. In most cases, the fatigue strength of the part and the small amount of deflection due to the rigid installation must be measured with high precision. It is arranged perpendicularly to the piping, and in order to increase the amount of deflection due to the Coriolis force, increasing the length of this straight section has the disadvantage that the main body of the device becomes larger.

Therefore, as described above, the present invention has been proposed to solve the problem of the conventionally known Coriolica mass flowmeter, which has a considerably large main body when installed in the piping system of an existing plant. In addition to having a large spread, there are various problems such as the fact that piping is affected by vibration in order to detect extremely small deflections. Not only can it be easily installed, but it also has low pressure loss. Due to the principle of the balanced measurement method, it is possible to measure deflection with high accuracy. The problem is to obtain a Coriolis mass flow meter that allows an accurate measurement of the mass flow rate of liquids, in particular, with a straight flow pipe in the direction of the pipe with little influence. It is something to do.

In order to solve this problem, the present invention first takes into account that the main pipe through which the fluid whose flow rate is to be measured is often a straight pipe, and also installs a mass flowmeter around it. In order to prevent the main body from requiring too much space, we use a straight pipe with the same linear axis as the piping as the measurement channel pipe, and use a balanced measurement method in terms of measurement technology.
In addition to improving measurement accuracy, the deflection of a straight pipe due to the Coriolis force is determined optically or electrically, for example, as a change in capacitance, and the signal obtained from this change is digitized, and this digitized signal can be used in a digital circuit, etc. The device is characterized in that it further reduces output deviation and increases measurement accuracy.

Originally, the Coriolis mass flowmeter measures the deflection of the flow pipe due to the Coriolis force and determines the flow rate from the relationship between this deflection and the flow rate, but when using a straight pipe in the Coriolis mass flowmeter Since deflection occurs in a direction perpendicular to the linear axis, if a vibrating channel tube is supported at both ends and the tube is fixed at the supports at both ends, the deflection will be reduced and the tube will not have an axis. directional stress will be generated.

Therefore, in order to avoid this, in the present invention,
The measurement flow pipe is supported by two support parts, but in this case, the flow pipe can be displaced in the axial direction at one support part, and the same Coriolis force can cause a large deflection. is supported by a vibratory free support mechanism, and the other support part is a vibration support part that allows the measurement channel tube to freely change its axial direction and to The structure is characterized in that vibration is applied in a direction perpendicular to the support part, and a part in which a measurement flow path tube is formed in a coil shape is provided on one or both sides of the outside of the support part.

This coiled tube portion corresponds to a change in tube length between both support portions due to deflection of the measurement flow path tube, and the change in tube length is transmitted to the coiled tube portion via the fixed support portion. By changing the radius of curvature of this coiled tube portion, it is possible to respond to changes in tube length.

Furthermore, the other support part is formed as a vibration support part, and in order to give rotational vibration to this support part, this support part is formed as an eccentric rotating part attached to a motor shaft installed in a frame fixed in space. Vibration is caused by an electromagnetic exciter consisting of a disk or a coil and an iron core, and this excitation force is transmitted to the measurement flow path pipe via the vibration support part, but this excitation force The spring force of the flow pipe section that opposes is
Another feature of the present invention is that the vibration is generated by the elastic force of the coiled tube formed on the outside of the vibration support.

In addition to these, in order to accurately measure the deflection due to the Coriolis force of the measurement channel pipe, we
Two compensating straight pipes having the same material and dimensions are placed parallel to and on both sides of the measuring straight pipe through which the fluid flows, and with the compensating straight pipes on both sides as a reference, the central measuring straight pipe through which the fluid flows. It has a structure that measures the amount of deflection of the pipe due to Coriolis force.

By adopting this structure, all influences other than Coriolis, which may cause deflection of the central measurement pipe, can be removed from the extracted signal.
Another feature is that only a signal proportional to the deflection of the central measuring pipe due to the Coriolis force can be obtained, resulting in high measurement accuracy.

Furthermore, the mass flowmeter according to the present invention is composed of a straight pipe section and one or two coiled pipe sections, and does not have a structure that causes a particularly large pressure loss. Another feature is that the flow velocity in the straight pipe for measuring deflection is set to 20 m/s or more to ensure that sufficient Coriolis acts.

Circle-1-1 Hereinafter, the present invention will be explained in detail based on FIGS. 1 to 5 of the accompanying drawings showing embodiments of the apparatus.

First, FIGS. 1 and 2 schematically show one embodiment of the present invention. As can be seen from these figures, the mass flowmeter 60 according to the present invention has a rectangular planar outline and a low height. Along the longitudinal center line XX of the hollow external frame 20 having a certain length, a straight measurement pipe 21, which is a channel pipe on which Coriolika acts, has a certain length, and at each end thereof, In addition to being fixedly disposed on each opposing side wall of the external frame 20, near each longitudinal end thereof,
Vibration support portions 22 and fixed support portions 23, which are appropriately arranged on the external frame 20 in a direction transverse to the longitudinal direction of the straight pipe 21, allow free movement in the axial direction and also prevent changes in the angle of the axis. Of these support parts 22 and 23, the vibration support part 22 is supported by the outer frame 2.
It is attached so that it can freely vibrate in the vertical direction with respect to 0.
The other fixed support part 23 is fixed to the external frame 20.

In addition, at each end of the straight pipe 21, an inlet pipe part 24 and an outlet pipe part 25 are connected coaxially with the straight pipe 21.
In order to increase the flow velocity inside the pipe 1, its inner diameter is made small, but a constriction part 26 is provided downstream of the inlet pipe part 24.
Further, enlarged portions 27 are formed upstream of the outlet pipe portions 25, respectively, to prevent any loss other than the internal pressure loss caused by reducing the inner diameter of the straight pipe portion 21. .

Furthermore, in the straight pipe 21 , a coiled pipe part 31 has a certain radius of curvature downstream of the constricted part 26 and upstream of the vibration support part 22 , and has a coiled pipe part 31 that is arranged along the axis X-X of the straight pipe 21 . The portion of the straight pipe 21 that is formed in communication with the straight pipe 21 and connected to its downstream end lies in a horizontal plane containing the
It is designed to be supported by a vibration support section 22. Further, downstream of the fixed support part 23 of the straight pipe 21, another coiled pipe part 32 similar to the coiled pipe part 31 is formed so as to communicate with the straight pipe 21. Part 32
The inlet end of an enlarged portion 27 formed in the outlet pipe 25 is connected to the end of the straight pipe 21 that is connected to the outlet end of the straight pipe 21 .

In addition, in the above description, the aperture part 26 and the enlarged part 2
7 are respectively formed downstream of the inlet pipe part 24 and upstream of the outlet pipe part 25 of the straight measurement pipe 21, but instead of this, the constricted part 26 is formed in the inlet coiled pipe part 31.
The enlarged portion 27 may be provided between the measuring straight pipe 21 and the measuring straight pipe 21, and between the measuring straight pipe 21 and the outlet coiled pipe portion 32.

In this way, coiled tubular sections 31.32 are formed upstream and downstream of the measurement straight pipe 21, respectively, and the outlet of the upstream coiled tubular section 31 of these coiled tubular sections 31.32 is formed. When the constriction section 26 and the enlarged section 27 are provided at the inlet of the downstream coiled tube section, the coiled tube section 3
The pressure loss at 1.32 can be reduced.

In this case, a constricted part 26 is further formed upstream of the upstream coiled tube part 31 and an enlarged part 27 is formed at the outlet of the downstream coiled tube part 32, and these constricted parts 2
Pressure loss can be further reduced by connecting the inlet pipe part 24 and the outlet pipe part 23, whose pipe diameters have been expanded to the diameter of the external pipe, to the outer ends of the enlarged part 6 and the enlarged part 27, respectively. become able to.

In particular, as can be seen from FIG. 2, on both sides of the straight pipe 21, there are a pair of compensating straight pipes 33 and 34 having axes parallel to the axis X-X of the straight pipe 21. These compensating straight pipes 33, 34 are made of the same material as the measuring straight pipe 21 and have the same dimensions. These compensating straight pipes 33 and 34 are made so that the vibration support part 22 and the fixed support part 23 that support the straight pipe 21 are provided with a structure similar to that of the straight pipe 21 in the axial direction. Each compensating straight pipe 33.3 is supported so that its movement is not obstructed.
One end of 4 is free on the upstream side of the vibration support part 22, but the other end is firmly attached to the side wall of the external frame 20 together with the outlet end 25 of the straight pipe 21. , vibrationally fixed in free support.

In this way, the axis XX of the straight pipe 21 between both the support parts 22 and 23 due to the deflection of the straight pipe 21 for measurement is
The change in length along 21 and the two compensating straight pipes 33, 34 can be simultaneously displaced in the axial direction, thereby making it possible to This ensures that only the deflection of the straight tube 21 due to forces can be measured with high precision and that the straight tube 21 has a coiled tube section 3 formed on the outside of each support 22,23.
1.33 so that it can be pulled freely with the necessary axial force.

In addition, as shown in FIG. 3, the vibration support part 22 is made up of a rotary vibration part 40 and C13 straight pipes 21, 33, 34, which are integrally movable from above and below in the axial direction, and the angle of the axis can be changed. A pair of blocks 41.4 supporting
2, and its vertical center line Y at the top of the upper block 41.
- a pair of ball bearings 43, 44 spaced symmetrically with respect to Y; these ball bearings 4
3.44 is brought into contact with the periphery of the eccentric rotating disk 46 attached to the motor 45 fixedly installed on the external frame 20, so that the eccentric rotating disk 46 is driven by the motor 45. When rotates, the three straight pipes 21, 3
3.34 includes ball bearings 43.44 and blocks 41°4
Vibration in the vertical direction is applied via 2.

In this case, in order to apply vibration smoothly and continuously to the straight pipe 21, etc., the ball bearings 43 and 44 must be pressed around the eccentric rotating disk 46 at all times. It is necessary to always elastically press the upper block 41 upward as seen in FIG. The elastic force of the coiled tube portion 31 is useful. That is, the coiled tube part 31 is arranged so that when the vibration support part 22 is in the normal position, it is in a state where it always generates a force that pushes up the upper and lower blocks 41 and 42. When the motor 45 is driven, the vibration support section 22 is caused to vibrate at the same frequency as the rotational speed of the motor 45 by the eccentric rotating disk 46 via the ball bearings 43 and 44.

In addition, in this embodiment, the straight pipe 21 is installed horizontally so that the fluid can flow inside it, but both of its support parts, namely the vibration support part 22 and the fixed support part 23, are installed horizontally. so that only the d deflection due to the Coriolis force of the straight pipe 21 can be measured at approximately the center between
A deflection measuring section 50 as shown in FIG. 4 is provided. That is, this deflection measurement unit 50 has a pair of upper and lower blocks 51 and 52 arranged in a direction perpendicular to the axis of the straight pipe 21 for measurement, through which the fluid whose flow velocity is to be measured flows, and a pair of upper and lower blocks 51,52. A pair of compensating straight pipes 33.34 arranged on both sides of the straight pipe 21 are simultaneously held between the blocks 51.52, but in this case, the upper and lower blocks 51.5
2 is provided with a circular hole so as to concentrically and loosely surround the straight pipe 21, and around the hole, a pair of arc-shaped electrodes 5 are provided.
3 and 54, and these arc-shaped electrodes 53.5
4 and the straight pipe 21 made of metal.

In this way, the difference between the deflection of the measuring straight pipe 21 and the deflection of the compensating straight pipes 33, 34 on both sides of the straight pipe 21
This is the deflection due to the Coriolis force, and in order to be able to immediately measure the difference in deflection, two compensating straight pipes 33
．． 34 is used. By this means,
Vibration in the surrounding environment, deflection of the measuring straight pipe 21 due to inertia due to excitation, etc. have no effect on the change in capacitance, and only the deflection of the central measuring straight pipe 21 , to be able to be detected.

As can be seen from the above explanation, in the device of the present invention,
First, a fluid, particularly a liquid, is supported by the vibration support part 22 and the fixed support part 23 arranged at appropriate intervals on the external frame 20 so that it can move freely in the axial direction and change the angle of the axis. In this case, the fixed support part 23 does not prevent the movement of the straight pipe 21 in the axial direction, but the vibration support part 22 has a rotary eccentric disk 46 that allows the axial center x of the straight pipe 21 to be fixed. - A slight reciprocating vibration is made in the direction perpendicular to x, and this minute reciprocating vibration and the straight pipe 21
Based on the fact that the deflection of the straight pipe 21 due to the Coriolis force acting on the straight pipe 21 due to the fluid flowing inside the straight pipe 21 is proportional to the mass flow rate of the fluid, this deflection is formed by the electrodes 51, 52 and the straight pipe 21. The change in capacitance of the fluid is electrically measured with high precision, and the mass flow rate of the fluid can be determined from the measurement results. For this reason, in the present invention, the straight pipe 21 is
In order to increase the flow rate of the fluid in the inlet pipe section 24,
A constriction part 26 is provided in the straight pipe 21 to increase the flow velocity in the straight pipe 21 by about 5 to 10 times that in the inlet pipe part 24.
．． A rotary eccentric disk 46 driven by a motor 45 via a rotary eccentric disk 44 causes the straight pipe 21 to reciprocate vertically.
However, the upper and lower blocks 35 and 36 supporting it and both ball bearings 4 attached to the upper block 35
3.44, the coiled tube section 31 for generating this elastic force presses the periphery of the rotating eccentric disk 46 with an appropriate elastic force. and the vibration support part 22.

The most important part in the device of the present invention is that between the vibration support part 22 and the fixed support part 23 of the measurement straight pipe 21 through which the fluid whose flow rate is to be measured flows, the axis X-X A pair of compensating straight pipes 33.34 made of the same material and having the same dimensions as the measuring straight pipe 21 is arranged parallel to and at the same distance from the measuring straight pipe 21, and these three straight pipes 21.33.
34 is held in both supporting parts 22.23, and is rigidly connected to both compensating straight pipes 33.34 at approximately the center in the longitudinal direction of these straight pipes 21, 33.34. .52, a pair of electric capacitors for measuring the deflection due to the Coriolis force of the straight measurement pipe 21, which is made of metal and has a fluid flowing inside it, as a change in capacitance! 53 and 54 are installed, and the change in capacitance is extracted as an electrical signal by these electrodes 53 and 54. With the above configuration, the signal of the change in capacitance is , the noise caused by the deflection of the three straight pipes 21, 33, and 34 due to their vertical reciprocating vibrations, and the vibration of the piping system placed before and after the device 1160 can be suppressed to a minimum. It becomes like this.

Furthermore, since the distance between the vibration support part 22 and the fixed support part 23 is given, the extension of the length of the measurement straight pipe 21 in the axial direction due to the deflection is 33°34 for each straight pipe 21. can be smoothly and slightly moved in the axial direction in the fixed support part 23, and the force resisting this movement is exerted by a coiled tube part formed downstream of the fixed support part 23. 32, it is now given. Further, the straight pipe 21 is provided with an enlarged part 27 downstream of the coiled pipe part 32 formed downstream of the fixed support part 23, and this enlarged part 27 is connected to the outlet pipe part 25 downstream thereof. ing.

As can be seen from the above description, the device of the present invention not only can be easily installed in a part of a straight pipe in a piping system such as a plant and takes up a small space, but also can be used for measurement using the Coriolis force. In order to measure the mass flow rate of the fluid flowing inside the straight pipe 21 by measuring the deflection of the straight pipe 21, the straight pipe 21 is supported near one end by a fixed support part 23 so as to be movable in the axial direction, In addition, the vibration support part 22, which vibrates vertically and reciprocally near the other end, supports the straight pipe 21 movably in the axial direction, and accurately prevents deflection due to the Coriolis force of the straight pipe 21, which vibrates vertically and reciprocally. For the measurement, a pair of compensating straight pipes 33, 34 made of the same material and having the same dimensions as the straight pipe 21 are placed in parallel with the straight pipe 21 in the vibration support 22 and the fixed support 23. The deflection measurement unit 50 that measures the deflection of the straight pipe 21 due to the Coriolis force is installed at approximately the center in the longitudinal direction of both the support parts 22.23, and the compensation straight pipe 33.34
Furthermore, electrodes 53 and 54 that form electric capacitance are attached to the upper and lower blocks 51 and 52, which are the fixing members of the deflection measuring section 50, to determine the mass of the fluid flowing in the straight measurement pipe 21. It becomes possible to measure the flow rate and the deflection due to the Coriolis force, which is proportional to the angular velocity of the straight pipe 21 due to vibration, with high precision as a change in capacitance.

In addition, in conventional Coriolis mass flowmeters, the free end of the loop-shaped flow pipe that bends due to Coriolis force is fixedly supported. However, with the device of the present invention, such problems will not occur at all. It is now possible to perform measurements even when there is no
The fatigue failure that can occur in conventional Coriolis mass flowmeters is significantly accelerated by the presence of liquid and chemically active liquid; however, the present invention eliminates such fatigue failure. Measurement using a mass flowmeter is now possible without worrying about what will happen.

For reference, the numerical analysis of the Coriolica mass flowmeter will be briefly explained as follows.

That is, in general, a measuring straight pipe 21 having a thickness t and an outer diameter d is supported in the vicinity of its both ends so as to be movable in the axial direction by two vibrating and fixed supporting parts 22 and 23 arranged at an interval l. One of these supporting parts 22 and 23 is fixed, and the other 22 is reciprocated up and down, so that the straight pipe 21
If the vibration acceleration is , the flow velocity of the fluid in the pipe is V, and the elastic modulus of the pipe material is E, then the deflection δ at approximately the center of the straight pipe is, and if the density of the fluid is ρ, the value of the thickness t is , is very small compared to the outer diameter d, so the deflection δ is proportional to ρ Vmut'/Edt, and if the mass flow rate is H, the deflection δ is Nω
It is proportional to I'/Ed't. Note that Coriolis is expressed as 2ρV.

Therefore, in order to increase the deflection δ due to the Coriolis force, use a straight measurement pipe 21 with a small outer diameter d, and increase the flow rate V
It turns out that it is necessary to make it larger.

In addition, when measuring the deflection of the measuring straight pipe 21, in order to eliminate the influence of external noise on this deflection δ, the angular acceleration of the measuring straight pipe 21 is zero, or the time before and after that moment is changed. A highly accurate mass flow rate can be determined by averaging the deflections within a limited time range that has the same finite time range.

The device of the present invention has the above-mentioned configuration and function.Next, numerical examples of measurement results performed by this device will be explained.

1-Wataru-1 With the device of the present invention, 2++ inside a pipe with an inner diameter of 25.4 mm
A numerical example will be explained when measuring the mass flow rate of a water stream flowing at a flow rate of +/s.

A water stream flowing at a flow rate of 2 m/s is guided to a coiled tube section 31 with an inner diameter of 91 mm, for example, by a constriction section 26 attached to the inlet tube section 24 of the device of the present invention, and the coiled tube section 31 However, by utilizing the fact that the coil generates a repulsive force against the action of increasing the curvature of the coil, this repulsive force is used to move the straight pipe 21 up and down in order to cause Coriolika to act on the measuring straight pipe 21 through which the fluid flows. A rotating eccentric disk 46 that causes reciprocating rotational vibration is brought into close contact with a block 41.42 attached to a straight pipe zH through ball bearings 43°44.The 0 rotation vibration is 1.500 times per minute. The vibration is carried out at a distance of 21 or 4 m, which is attached to the shaft of the motor 45.
This was carried out using an eccentric rotating disk 46 having an eccentricity of m. Note that the measurement straight pipe 21 was supported by both support parts 22 and 23 arranged at an interval of I=0.5 m.

In addition, as already mentioned, the sag due to the Coriolis force δ
In order to increase the measurement straight pipe 2 with a small outer diameter d.
1, it is clear that it is necessary to increase the flow velocity V. However, if a straight pipe 21 that is too thin is used, a large pressure loss will occur, so the outer diameter d of the straight pipe in the measurement section is 1O.
n+m, wall thickness = 0.5 mm, the eccentric rotary disk 46 is rotated in this straight pipe at a frequency of 25 Hz, and the flow velocity V in the straight pipe 21 is about 16 m/s, then the straight pipe 21 has I= 0.
At the center of both supports 22, 23, which are separated by a distance of 5 m, the Coriolis force causes a deflection δ of approximately 1100 Ji. When this deflection δ is detected as a change in capacitance by the deflection measurement unit 50 shown in FIG.
When measured by applying a Hz alternating current, a difference of about 15 pF was detected.

The present invention has the above-mentioned structure and operation, and as can be seen from the above numerical examples, it is clear that the present invention achieves the intended purpose. be.

Here, the gist of the present invention can be summarized as follows.

■When determining a mass flow meter by measuring the deflection of a straight pipe due to Coriolis force, the deflection due to the inertial force that occurs when the straight pipe is rotated and vibrated back and forth is measured when fluid flows through a straight pipe vibrating under the same conditions. Coriolis force can be measured by installing two parallel pipes on both sides of a straight pipe and measuring the difference between the deflection of the two straight pipes on both sides and the deflection of the measuring straight pipe through which the fluid whose flow rate is to be measured flows. It is possible to take out and measure only the deflection of a straight pipe due to vibrations.It supports the vicinity of both ends of the measuring straight pipe that vibrates and fluid flows, allowing it to be freely displaced, thereby reducing the large stress caused by holding the straight pipe and causing fatigue failure. Since the structure that causes It is designed to be sufficiently deflected by the Coriolis force, and by using a thin walled tube with a small diameter only for the straight tube for measurement, the diameter of other parts is Even if it is made as large as possible, it is possible to ensure that the deflection due to the Coriolis force is sufficiently large due to the coiled pipe sections formed upstream and downstream of the straight measurement pipe, and the mass flow rate can be measured accurately. These include things that can be done.

Due to these features, the following effects can be mentioned as effects of the present invention. In other words, ■ The device of the present invention can be installed in the middle of a horizontal or vertical straight pipe. In this case, a straight pipe with a small inner diameter is used only for the measurement part, and the deflection due to the Coriolis force is measured using a balanced measurement method. Because it is a mass flow meter, it is possible to accurately measure mass flow rate without requiring any special conditions for external piping, and even though the measurement is performed in a relatively small space. ■Conventional mass flowmeters that use Coriolis mostly involve a large pressure loss, but the device of the present invention has a structure that can reduce pressure loss. Moreover, a feature of the mass flow meter that uses Coriolica is that it does not depend on the physical property values of the fluid and can accurately measure the mass flow rate of liquids with new chemical structures. Conventionally, when vibrating a straight pipe for measurement, the pipe is often rigidly supported, and as a result, considerable stress is generated in the pipe near the supporting part at the time of maximum vibration, which can cause fatigue failure. However, in the device of the present invention, there is no such rigid support part at all, and the support is not only free but also Since the coiled tube part is formed upstream, it can freely take displacement in the axial direction due to deflection, and has high reliability as a measuring instrument.In this way, the device of the present invention has the following features: It is possible to provide the industrial world with a reliable measuring instrument that has a wide range of applications as a future mass flowmeter mainly for liquids, has high accuracy, and has a long life.

[Brief explanation of the drawing]

FIG. 1 is an overall plan view showing one embodiment of the apparatus according to the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a II of FIG. 1.
The cross-sectional view taken along line I-III and FIG. 4 are the same (TV-T
FIG. 5, a cross-sectional view taken along the V line, is a perspective view showing a typical Coriolika mass flowmeter that has been used in the past. -20... External frame, 21... Straight pipe for measurement, 22...
- Vibration support part, 23... Fixed support part, 24... Inlet pipe part, 25... Outlet pipe part, 26... Throttle part, Z7.
... Enlarged part, 31.32 ... Coiled tube part, 33.3
4...Compensating straight pipe, 40...Rotating vibration part, 41.42
．． 5152...Block, 43.44...Ball bearing,
45...Motor, 46...Eccentric rotating disk, 50...
- Deflection measuring section, 53.54... Electrode, 60... Coriolis force straight pipe mass flowmeter.

Claims (1)

[Claims] 1. Single-phase liquid, gas, or liquid and gas, or
In order to measure the mass flow rate of a fluid such as a two-phase flow in which gas and minute solids, gas and mist, or minute solids are mixed, an inlet pipe section for introducing the fluid and an outlet for discharging the fluid. It consists of a straight measuring tube having a certain length with a tube section formed at each end.
This measuring straight pipe is attached to a pair of opposing side walls of an external frame having a substantially rectangular planar outline at the ends of its inlet pipe portion and outlet pipe portion. Near one end, the tube is supported movably in the axial direction by a fixed support part on the external frame, and near the other end, a vibration support part on the external frame makes it possible to change the angle of the axis and to provide direct measurement. The pipe is supported so as to be given reciprocating vibration in a direction perpendicular to the axis of the pipe, and in this way, when the fluid flows through the measurement straight pipe, which is given rotational vibration by the vibration support, the fluid is Coriolis force straight pipe mass, characterized in that the mass flow rate of a fluid is measured by measuring the deflection that occurs in the measurement straight pipe based on the Coriolis force generated by receiving rotational vibration through the straight pipe. Flowmeter. 2.Insert a pair of compensating straight pipes, which have an axis parallel to the axis of the measuring straight pipe in the external frame and are made from the same material and have the same dimensions, on both sides of the measuring straight pipe at a distance from this. Place the
These compensating straight pipes are fixed at one end to a side wall, etc., to which the end of the outlet pipe of the measuring straight pipe of the outer frame is attached, and they are fixed together with the measuring straight pipe to a fixed support. and Claim 1, wherein the vibration support part supports the vibration support part.
Coriolis force straight tube mass flowmeter as described. 3. Deflection due to the Coriolis force of the measurement straight pipe and the pair of compensation straight pipes arranged parallel to each other,
Coriolis force correction according to claim 2, wherein the measurement is carried out electrically or optically with reference to the compensation straight pipes arranged on both sides of the compensation straight pipe, thereby measuring the mass flow rate of the fluid flowing inside the measurement straight pipe. Tube mass flow meter. 4. A coil having a predetermined curvature between the inlet pipe part and the vibration support part and between the outlet pipe part and the fixed support part, respectively, in the upstream part and/or downstream part of the straight measurement pipe. 4. The Coriolis force straight tube mass flowmeter according to claim 1, wherein the Coriolis force straight tube mass flowmeter is formed into a tubular section. 5. The vibration support part is spaced between a pair of blocks that support the measurement straight pipe and the compensation straight pipe so that the axis angle can be changed, and a pair of blocks arranged on the outer surface of one of the blocks. An eccentric rotating disk is in contact with these ball bearings at the periphery, and this eccentric rotating disk is rotationally driven by a motor attached to an external frame. The Coriolis force straight tube mass flowmeter according to any one of claims 1 to 4. 6. By providing a constriction part between the inlet pipe part of the straight measuring pipe or the straight measuring pipe and the inlet coiled pipe part, the inner diameter can be reduced, and the inner diameter can be reduced. Claim 1: An enlarged portion is formed between the pipe and the pipe, so that when the flow velocity of the fluid in the straight measurement pipe is increased, the pressure loss of the fluid does not become substantially large.
6. The Coriolis force straight tube mass flowmeter according to any one of items 5 to 5.