Coriolis flow meter

Abstract

The utility model provides a Coriolis flow meter, the upstream end and the downstream end of a flow guide pipe in a chamber of a meter shell are respectively connected with an opening and closing valve and a liquid outlet pipe, the midstream section of the flow guide pipe is an expanding section, a sensing device is arranged at the position close to the free end of a vibration rod in the flow guide pipe, vibration signal output of the vibration rod is collected, and a flow value is obtained. According to the scheme, the diameter expanding section increases the Coriolis force which is generated by the fluid in the flow guide pipe and is perpendicular to the vibrating rod, so that a vibration signal generated by the vibrating rod under the same flow is more easily measured by a sensing device, and the measuring sensitivity of the flowmeter is further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of fluid measurement, in particular to a Coriolis flowmeter. Background Art

[0002] A flow meter is an instrument used to measure the flow rate of a fluid in a pipeline. A flow meter designed using the Coriolis force principle has the advantages of being able to directly measure the flow rate and having high measurement accuracy. The Coriolis flow meter in the prior art is usually designed as a measuring tube with an electromagnetic vibrator and two vibration sensors, which measures the vibration signal when the fluid passes through the measuring tube to feedback its flow rate.

[0003] The patent named "Fluid Oscillation Flowmeter" (US3698245A) discloses a technical solution, in which a reed assembly 17 is provided in the flow channel 16. When the fluid passes through the flow channel, the reed assembly 17 generates elastic oscillations, and the sensor responds to the output, thereby calculating the flow rate of the fluid. In the above solution, the flow channel 16 is a cylindrical through-pipe, and the Coriolis force of the fluid forming the vortex is relatively small. The vibration of the reed assembly 17 under the influence of the Coriolis force needs to be measured with a high-precision sensor device. The measurement sensitivity of this solution still has room for improvement. Utility Model Content

[0004] The utility model aims to provide a Coriolis flowmeter, which increases the measurement sensitivity of the flowmeter through the design of a pipeline structure.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a Coriolis flowmeter, the downstream end of the liquid inlet pipe is connected to the inner cavity of a tube box-shaped case, a flow guide pipe is arranged in the chamber of the case, the downstream end of the flow guide pipe is connected to the liquid outlet pipe, a valve plate of an opening and closing valve is arranged at the pipe mouth of the upstream end of the liquid outlet pipe, and when the valve plate is displaced, the chamber of the case and the upstream end of the flow guide pipe are cut off or connected, the midstream section of the flow guide pipe is an expanded diameter section, a vibration rod is arranged in the flow guide pipe, and a sensing device is arranged on the shell wall of the case near the free end of the vibration rod to collect vibration signals of the vibration rod and output the collected vibration signals.

[0006] The utility model mainly arranges a flow guide tube in a case chamber, a vibration rod is arranged in the flow guide tube, and an expansion section is arranged in the midstream section of the flow guide tube. The expansion section increases the Coriolis force perpendicular to the vibration rod generated by the fluid in the flow guide tube, so that the vibration signal generated by the vibration rod under the same flow rate is more easily measured by the sensor device, thereby improving the measurement sensitivity of the flow meter. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic diagram of the case of the Coriolis flowmeter;

[0008] Figure 2It is a schematic diagram of the internal structure of the Coriolis flowmeter;

[0009] Figure 3 is a cross-sectional view of a Coriolis flowmeter;

[0010] Figure 4 A schematic diagram of a case of another embodiment of a Coriolis flowmeter;

[0011] Figure 5 A cross-sectional view of another embodiment of a Coriolis flowmeter;

[0012] Figure 6 for Figure 5 Schematic diagram after removing the vibration rod and the opening and closing valve housing;

[0013] Figure 7 This is a schematic diagram of the Coriolis flowmeter with part of the case removed. DETAILED DESCRIPTION

[0014] See also Figure 1 In the Coriolis flowmeter shown, the downstream end of the liquid inlet pipe 1 is connected to the inner cavity of the tube box-shaped case 3, and a flow guide pipe 22 is arranged in the chamber of the case 3. The downstream end of the flow guide pipe 22 is connected to the liquid outlet pipe 2. A valve plate 211 of an opening and closing valve 21 is arranged at the pipe mouth of the upstream end of the liquid outlet pipe 2. When the valve plate 211 is displaced, it cuts off or connects the chamber of the case 3 and the upstream end of the flow guide pipe 22. The midstream section of the flow guide pipe 22 is an expanded diameter section 23. A vibration rod 30 is arranged in the flow guide pipe 22. A sensor device 40 is arranged on the shell wall of the case 3 near the free end of the vibration rod 30 to collect vibration signals of the vibration rod 30 and output the collected vibration signals.

[0015] In the above scheme, a spring 5 is provided in the cavity of the opening and closing valve 21, and the valve plate 211 is a rubber sheet pre-stressed by the spring 5 and sealing the upstream end of the outlet pipe 2. The pre-stressed pressure of the spring 5 can be adjusted and set on the opening and closing valve 21. Preferably, the opening and closing valve 21 can adopt a pilot valve, and the opening or closing of the opening and closing valve 21 is controlled by other control mechanisms. The vibration rod 30 in the guide tube 22 can be fixed at one end and freely suspended at the other end. The vibration rod 30 can be made of elastic materials, such as stainless steel sheets, phosphor copper sheets and plastic sheets, and the free end of the vibration rod 30 vibrates when the fluid passes through. The expansion section 23 can increase the vortex path of the fluid in the guide tube 22. After the fluid passes through the expansion section 23, the eddy current oscillation generated is more intense, which is convenient for the sensor device 40 to collect vibration signals, thereby improving the measurement sensitivity of the flow meter.

[0016] In order to improve the range ratio of the Coriolis flowmeter, a pulse ejector 11 is arranged on the tube wall of the flow guide tube 22, and the liquid inlet end of the pulse ejector 11 is connected to the chamber of the case 3, and the jet of the pulse ejector 11 is directed to the free end or segment of the vibration rod 30. In the above scheme, after the fluid enters from the liquid inlet end of the pulse ejector 11, it is divided into two paths at its downstream end, one path along the inner cavity of the tube box-shaped case 3 to reach the valve plate 211 of the opening and closing valve 21, and the other path enters the inner cavity of the case 3 from the liquid inlet end of the pulse ejector 11 on the tube wall. There are two possible situations here:

[0017] 1. When the fluid flow is small, the fluid pressure is small, and the fluid pressure flowing from the inner cavity of the case 3 to the valve plate 211 is not enough to open the valve plate 211. The fluid can only enter the downstream end of the inner cavity of the flow guide tube 22 from the pulse ejector 11 on the wall of the flow guide tube 22, and flow out from the liquid outlet pipe 2. Since the jet of the pulse ejector 11 points to the free end or segment of the vibration rod 30, the free end of the vibration rod 30 will vibrate under the impact of the jet. After the sensor device 40 collects the vibration signal of the vibration rod 30, the processor collects the vibration signal and processes it through the corresponding algorithm to obtain the flow rate of the fluid.

[0018] Second, when the fluid flow rate is large, the fluid pressure flowing from the inner cavity of the case 3 to the valve plate 211 is sufficient to open the valve plate 211, and the fluid enters the guide tube 22 through the on-off valve 21, forming a vortex in the guide tube 22 to vibrate the vibration rod 30. In this process, part of the fluid still enters through the liquid inlet 111 of the pulse ejector 11, and the two fluids merge at the downstream end of the guide tube 22 and flow out from the liquid outlet pipe 2. At this time, the measurement of the flow meter is based on the Coriolis force principle. The vortex in the guide tube 22 and the jet of the pulse ejector 11 merge and act on the vibration rod 30 to produce resonance. The sensor device 40 collects the vibration signal synthesized by the above two vibrations. The vibration signal obtains the magnitude of the Coriolis force generated by the fluid through the corresponding algorithm, and then measures the flow rate.

[0019] Therefore, the Coriolis flowmeter of the present solution can measure both flow conditions mentioned above, and can measure both large flow and small flow, and both have high measurement accuracy. Compared with the traditional flowmeter, the Coriolis flowmeter of the present solution obviously has a larger range ratio. In the present invention, when the flowmeter measures different fluid media, it can select the corresponding vibration rod 30 with different Young's modulus according to the medium with different densities. For example, when measuring water flow and air flow with similar flow rates, the Young's modulus of the vibration rod 30 used to measure the water flow is greater than the Young's modulus of the vibration rod 30 used to measure the air flow.

[0020] The outer surface of the tube wall at the downstream end of the flow guide tube 22 is connected with a partition 8 that separates the liquid inlet tube 1 and the liquid outlet tube 2. The partition 8 is annular as a whole and is obliquely placed in the chamber of the watch case 3 so that the liquid outlet tube 2 is only connected to the downstream end of the flow guide tube 22. The outer edge of the partition 8 abuts against the inner wall of the watch case 3 and a groove for accommodating a sealing ring is provided on the outer edge of the partition 8.

[0021] Specifically, the inner cavity of the expanded diameter section 23 is provided with two diverter blocks 232 which are arranged symmetrically relative to the core line of the guide tube 22. A first side passage 233 and a second side passage 234 are formed between the diverter blocks 232 and the tube wall of the expanded diameter section 23. A central channel 231 is formed between the two diverter blocks 232. The first side passage 233, the second side passage 234 and the central channel 231 form a parallel channel. The central channel 231 is expanded from the upstream end to the downstream end, and the inner diameter of the downstream end of the central channel 231 is larger than the inner diameter of the downstream section of the guide tube 22.

[0022] In the above scheme, the pipe opening of the flow guide pipe 22 adjacent to the valve plate 211 is divided into three at the expanded diameter section 23, forming a first side passage 233, a second side passage 234 and a central passage 231 which are connected in parallel to each other, and the three are merged at the downstream end of the expanded diameter section 23. When the flow meter is working, the fluid enters the flow guide pipe 22 from the inner cavity of the case 3 through the on-off valve 21, and first enters the central passage 231 at the expanded diameter section 23. Since the central passage 231 is expanded from the upstream end to the downstream end, and the inner diameter of the downstream end of the central passage 231 is larger than the inner diameter of the downstream section of the flow guide pipe 22, part of the branch flow will be separated from the fluid flowing downstream from the central passage 231, and enter the first side passage 233 and the second side passage 234 respectively, and merge at the upstream end of the expanded diameter section 23 and flow back to the entrance of the central passage 231. The fluid in the central channel 231 is affected by the backflow, and the generated eddy current oscillation is more intense, acting on the vibration rod 30 located in the central channel 231, so that the vibration signal measured by the sensor device 40 is more accurate.

[0023] As a preferred embodiment, the sensor device 40 includes a magnet 401 fixed at the free end of the vibration rod 30 and a Wiegand sensor 402 arranged adjacent to the magnet 401. The Wiegand sensor 402 is fixed on the shell wall of the watch case 3 at the downstream end of the guide tube 22. The Wiegand sensor 402 has the advantages of not requiring an external power supply and accurate measurement. The vibration signal can be measured by using the magnet 401 in combination with the Wiegand sensor 402, and high-precision measurement of large and small flows can be achieved through algorithms. It should be noted that the sensor device 40 of the present invention is not limited to the above-mentioned embodiment. The sensor device 40 may also use an angular velocity sensor, a Hall sensor, or other sensors that collect vibration signals using laser measurement, electrical measurement, or the like.

[0024] In order to obtain the vibration signal of the vibration rod 30 more accurately, the vibration rod 30 is in a strip shape, and the length direction of the vibration rod 30 is consistent with the core line direction of the guide tube 22.

[0025] Preferably, the core line of the vibrating rod 30 coincides with the core line of the guide tube 22. In the above scheme, the strip-shaped vibrating rod 30 has a larger force-bearing area in the oscillation of the fluid, which is conducive to the vibration of the free end of the vibrating rod 30. The core line of the vibrating rod 30 coincides with the core line of the guide tube 22, so that the cavities on both sides of the vibrating rod 30 are symmetrical, which facilitates the sensor device 40 to collect vibration signals.

[0026] More specifically, a bracket 311 connected to the pipe wall is provided in the guide pipe 22 . The bracket is in an I-shape or a X-shape and is horizontally placed in the pipe. The middle section or one end of the vibration rod 30 is fixedly connected to the bracket 311 .

[0027] As a preferred solution, a check plate 6 is provided on the communication path between the downstream end of the flow guide pipe 22 and the liquid outlet pipe 2. The check plate 6 is hingedly connected to the outer tube wall of the flow guide pipe 22 and swings to the conducting position and the check position respectively when rotating around the hinge axis. When in the check position, the check plate 6 covers the downstream end of the flow guide pipe 22 and the tube mouth of the downstream end of the liquid outlet pipe 2 is within the plate surface of the check plate 6. When in the conducting position, a conducting path is formed between the downstream end of the flow guide pipe 22 and the liquid outlet pipe 2. The check plate 6 is connected to the outer tube wall of the flow guide pipe 22 by a hinge. Under normal working conditions, after the fluid enters from the liquid inlet pipe 1, it flows from the downstream end of the flow guide pipe 22 to the liquid outlet pipe 2. Under the impact of the fluid, the check plate 6 swings around the hinge axis to the conducting position. When the fluid enters from the liquid outlet pipe 2, the impact of the fluid causes the check plate 6 to be in the check position, thereby sealing the downstream end of the guide pipe 22, thereby cutting off the flow of the fluid.

[0028] Preferably, the valve plate 211 of the on-off valve 21 is provided with a through hole 7 and a pressure relief valve 212, respectively. The through hole 7 connects the isolation chamber 4 and the water passage chamber. One end of the pressure relief valve 212 is located in the isolation chamber 4, and the other end extends into the flow guide pipe 22 or extends to the communication path between the flow guide pipe 22 and the liquid outlet pipe 2. In the above scheme, when the pressure relief valve 212 is closed, the fluid entering from the liquid inlet pipe 2 enters the isolation chamber 4 from the through hole 7 on the valve plate 211, and the fluid in the isolation chamber 4 generates pressure on the valve plate 211, so that the valve plate 211 is pressed and cannot be opened, and the flow meter plays a role of intercepting flow; when the pressure relief valve 212 is opened, the isolation chamber 4 of the valve plate 211 is depressurized, and the flow meter works normally.

[0029] like Figure 7As shown, as a preferred embodiment, a bottom plate 53 is arranged near the downstream end of the guide tube 22, and the plate surface of the bottom plate 53 faces the downstream end of the guide tube 22. An isolation cavity is provided on the side of the bottom plate 53 away from the guide tube 22, and a magnet block 50 is arranged in the isolation cavity. The magnet block 50 is connected to the plate surface of the bottom plate 53 through the through hole of the isolation cavity. A spring 52 is arranged on the side of the magnet block 50 away from the bottom plate 53, and the two ends of the spring 52 respectively abut the magnet block 50 and the inner wall of the isolation cavity of the watch case 3, and magnetic induction coils 51 fixed in the isolation cavity are arranged near both sides of the magnet block 50.

[0030] In the above scheme, when the Coriolis flowmeter is working, the fluid flows out from the downstream end of the guide tube 22 and impacts the bottom plate 53. After the bottom plate 53 is impacted, the spring 52 abutting against the magnet block 50 generates a reaction force on the magnet block 50, and the magnet block 50 and the bottom plate 53 connected thereto vibrate. During the vibration process, the magnet block 50 cuts the magnetic flux lines of the magnetic induction coil 51 to generate current, charge the capacitor and battery, and is controlled by the processor of the flowmeter and supplies power to other modules, so that the flowmeter can power itself during the measurement process, thereby improving the convenience of the flowmeter measurement and enabling it to still work in an environment without an external power supply.

[0031] The Coriolis flowmeter of the utility model can be applied to water meters or gas meters. Figure 4 , Figure 5 As shown, as another embodiment, the pipe openings of the liquid inlet pipe 1 and the liquid outlet pipe 2 connected to the housing 3 can be arranged toward the same side to facilitate application in scenes such as water pipes and gas pipelines.

Claims

1. A Coriolis flowmeter, characterized in that: The downstream end of the liquid inlet pipe (1) is connected to the inner cavity of a tube box-shaped case (3); a flow guide pipe (22) is arranged in the chamber of the case (3); the downstream end of the flow guide pipe (22) is connected to the liquid outlet pipe (2); a valve plate (211) of an opening and closing valve (21) is arranged at the pipe mouth of the upstream end of the liquid outlet pipe (2); when the valve plate (211) is displaced, the chamber of the case (3) and the upstream end of the flow guide pipe (22) are cut off or connected; the midstream section of the flow guide pipe (22) is an expanded diameter section (23); a vibration rod (30) is arranged in the flow guide pipe (22); a sensing device (40) is arranged on the shell wall of the case (3) near the free end of the vibration rod (30) to collect vibration signals of the vibration rod (30) and output the collected vibration signals.

2. The Coriolis flowmeter according to claim 1, characterized in that: A pulse jet (11) is arranged on the tube wall of the flow guide tube (22), the liquid inlet end of the pulse jet (11) is connected to the chamber of the watch case (3), and the jet of the pulse jet (11) is directed to the free end or section of the vibration rod (30).

3. The Coriolis flowmeter according to claim 1 or 2, characterized in that: The inner cavity of the expanded diameter section (23) is provided with two flow dividing blocks (232) symmetrically arranged relative to the core line of the flow guiding tube (22); a first side passage (233) and a second side passage (234) are formed between the flow dividing blocks (232) and the tube wall of the expanded diameter section (23); a central channel (231) is formed between the two flow dividing blocks (232); the first side passage (233), the second side passage (234) and the central channel (231) form a parallel channel; the central channel (231) is in an expanded shape from the upstream end to the downstream end, and the inner diameter of the downstream end of the central channel (231) is larger than the inner diameter of the downstream section of the flow guiding tube (22).

4. The Coriolis flowmeter according to claim 1, characterized in that: The vibration rod (30) is in the shape of a strip, and the length direction of the vibration rod (30) is consistent with the direction of the core line of the flow guide tube (22).

5. The Coriolis flowmeter according to claim 4, characterized in that: The rod core line of the vibration rod (30) coincides with the tube core line of the flow guide tube (22).

6. The Coriolis flowmeter according to claim 1, characterized in that: The sensing device (40) comprises a magnet (401) fixed at the free end of the vibration rod (30) and a Wiegand sensor (402) arranged adjacent to the magnet (401); the Wiegand sensor (402) is fixed on the shell wall of the meter shell (3) at the downstream end of the flow guide tube (22).

7. The Coriolis flowmeter according to claim 1, characterized in that: A support (311) connected to the pipe wall is provided in the flow guide pipe (22). The support is in the shape of a letter "I" or a letter "X" and is horizontally placed in the pipe. The middle section or one end of the vibration rod (30) is fixedly connected to the support (311).

8. The Coriolis flowmeter according to claim 1, characterized in that: A check plate (6) is provided on the communication path between the downstream end of the flow guide pipe (22) and the liquid outlet pipe (2). The check plate (6) is hingedly connected to the outer pipe wall of the flow guide pipe (22) and swings to a conducting position and a check position respectively when rotating around a hinge axis. When in the check position, the check plate (6) seals the pipe opening at the downstream end of the flow guide pipe (22) and the pipe opening at the downstream end of the liquid outlet pipe (2) is within the plate surface of the check plate (6). When in the conducting position, a conducting path is formed between the downstream end of the flow guide pipe (22) and the liquid outlet pipe (2).

9. The Coriolis flowmeter according to claim 1, 4 or 5, characterized in that: A through hole (7) and a pressure relief valve (212) are respectively provided on the valve plate (211) of the opening and closing valve (21); the through hole (7) is in communication with the isolation chamber (4) and the water passage chamber; one end of the pressure relief valve (212) is located in the isolation chamber (4), and the other end extends into the flow guide pipe (22) or extends to the communication path between the flow guide pipe (22) and the liquid outlet pipe (2).

10. The Coriolis flowmeter according to claim 1, characterized in that: A bottom plate (53) is arranged near the downstream end of the flow guide tube (22), the plate surface of the bottom plate (53) faces the downstream end of the flow guide tube (22), an isolation cavity is arranged on the side of the bottom plate (53) away from the flow guide tube (22), a magnet block (50) is arranged in the isolation cavity, the magnet block (50) is connected to the plate surface of the bottom plate (53) through the through hole of the isolation cavity, a spring (52) is arranged on the side of the magnet block (50) away from the bottom plate (53), two ends of the spring (52) respectively abut against the magnet block (50) and the inner wall of the isolation cavity of the watch case (3), and magnetic induction coils (51) fixed in the isolation cavity are arranged near both sides of the magnet block (50).

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