Flowmeter

Abstract

The upstream end and the downstream end of a flow guide pipe in a cavity of a meter shell are connected with an opening and closing valve and a liquid outlet pipe respectively, jet flow of a pulse jet device on the pipe wall of the flow guide pipe points to the free end or section of a vibration rod in the flow guide pipe, and a sensing device is arranged at the position close to the free end of the flow guide pipe. Vibration signals of the vibration rod are collected and output to obtain a flow value. The flow guide pipe and the pulse jet device which are connected in parallel are arranged, when the flow of fluid is small, the fluid only enters the pulse jet device and impacts the vibration rod, then vibration signals are collected, and the flow value is calculated; when the flow of the fluid is large, the valve plate of the opening and closing valve is opened, the fluid enters the flow guide pipe from the cavity of the meter shell and is fused with the small-flow jet flow, the vibration rod vibrates, and the sensing device measures the flow value. The flowmeter is high in measurement accuracy and larger in measuring range ratio.

Description

Technical Field

[0001] The utility model relates to the technical field of fluid measurement, in particular to a flow meter. 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, there is only one straight flow channel, and it is difficult to measure accurately when the flow rate of the measured fluid is very small, and its range ratio is relatively small. Utility Model Content

[0004] The utility model aims to provide a flow meter with a large range ratio which can measure large flow and small flow at the same time.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a flow meter, the downstream end of the liquid inlet pipe is connected to the inner cavity of a tube box-shaped case, a guide pipe is arranged in the case chamber, the midstream section of the guide pipe is provided with a reduced diameter section, the downstream end of the guide pipe is connected to the liquid outlet pipe, and a valve plate of an opening and closing valve is arranged at the pipe mouth of the upstream end of the liquid outlet pipe. When the valve plate is displaced, the chamber of the case and the upstream end of the guide pipe are cut off or connected, a pulse ejector is arranged on the tube wall of the guide pipe, the liquid inlet of the pulse ejector is connected to the inner cavity of the case, the jet of the pulse ejector is directed to the free end or segment of the vibration rod arranged in the 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 the vibration signal of the vibration rod and output the collected vibration signal.

[0006] The utility model mainly sets a flow guide tube and a pulse ejector in parallel with each other, and sets an opening and closing valve at the pipe mouth at the upstream end of the liquid outlet pipe. When the flow rate of the measured fluid is very small, the fluid only enters the pulse ejector. After impacting the vibration rod, the sensor device collects the vibration signal of the vibration rod and outputs it, and the measured value of the flow rate is obtained through the system algorithm; when the flow rate of the measured fluid is large, the fluid pressure is greater than the set pressure of the opening and closing valve, the valve plate opens, and under the excitation of the jet pulse of small flow rate, the fluid enters the flow guide tube from the chamber of the case at the same time, and the small flow rate and the large flow rate merge and act on the vibration rod to make it vibrate, and the sensor device measures the vibration signal and obtains its flow value under the system algorithm. The flow meter of the present invention can measure both large flow rate fluids and small flow rate fluids through the above scheme, both of which have high measurement accuracy, and the range ratio is larger than that of traditional flow meters. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic diagram of a flow meter case;

[0008] Figure 2 is a cross-sectional view of the flow meter;

[0009] Figure 3 A cross-sectional view of a pulse jet. DETAILED DESCRIPTION

[0010] See also Figures 1-2 In the flow meter 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, and 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. A pulse ejector 11 is arranged on the tube wall of the flow guide pipe 22, and the liquid inlet 111 of the pulse ejector 11 is connected to the inner cavity of the case 3. The jet of the pulse ejector 11 is directed to the free end or segment of the vibration rod 30 arranged in the flow guide pipe 22, and 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 the vibration signal of the vibration rod 30 and output the collected vibration signal.

[0011] In the above scheme, a spring 5 is provided in the cavity of the on-off valve 21, and the valve plate 211 is a rubber sheet which is pre-stressed by the spring 5 and seals the upstream end of the liquid outlet pipe 2. The pre-stressed pressure of the spring 5 can be adjusted and set on the on-off valve 21. Preferably, the on-off valve 21 can adopt a pilot valve, and the opening or closing of the on-off 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 bronze sheets and plastic sheets, and the free end of the vibration rod 30 vibrates when the fluid passes through. Figure 1As shown, when the flow meter is working, after the fluid enters from the liquid inlet pipe 1, it is divided into two paths at its downstream end, one path reaches the valve plate 211 of the on-off valve 21 along the inner cavity of the tube box-shaped case 3, and the other path enters the inner cavity of the case 3 from the liquid inlet 111 of the pulse ejector 11 on the pipe wall. There are two possible situations here:

[0012] 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 liquid inlet 111 of 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.

[0013] 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.

[0014] Therefore, the flowmeter of the present invention can measure under the above two flow conditions, and can measure both large flow fluids and small flow fluids. Both have high measurement accuracy. Compared with traditional flowmeters, the flowmeter of the present invention obviously has a larger range ratio. In the present invention, when measuring different fluid media, the flowmeter can select corresponding vibration rods 30 with different Young's moduli according to media 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.

[0015] 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.

[0016] 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 .

[0017] Preferably, the rod core line of the vibration rod 30 coincides with the tube core line of the guide tube 22. The midstream section of the guide tube 22 is provided with a reduced diameter section 221, and the middle section of the vibration rod 30 is located in the reduced diameter section 221. In the above scheme, the strip-shaped vibration rod 30 has a larger force-bearing area during the oscillation of the fluid, which is conducive to the vibration of the free end of the vibration rod 30. The rod core line of the vibration rod 30 coincides with the tube core line of the guide tube 22, so that the tube cavities on both sides of the vibration rod 30 are symmetrical. After the fluid passes through the reduced diameter section 221 in the guide tube 22, the vortex oscillation generated by the fluid is more intense, which is convenient for the sensor device 40 to collect vibration signals.

[0018] Specifically, the pipe section between the liquid inlet 111 and the outlet tube 112 of the pulse ejector 11 is an expanded diameter section 113, and the inner cavity of the expanded diameter section 113 is provided with two diverter blocks 114 arranged symmetrically relative to the tube core line of the expanded diameter section 113. The diverter blocks 114 and the tube wall of the expanded diameter section 113 form a first side passage 116 and a second side passage 117, and the two diverter blocks 114 form a central channel 115. The first side passage 116, the second side passage 117 and the central channel 115 form a parallel channel. The central channel 115 is expanded from the upstream end to the downstream end, and the inner diameter of the downstream end of the central channel 115 is larger than the inner diameter of the outlet tube 112. The jet of the pulse ejector 11 impacts the vibration rod 30 to collect small flow signals.

[0019] In the above scheme, the downstream end of the liquid inlet 111 is divided into three parts at the expanded diameter section 113, forming a first side passage 116, a second side passage 117 and a central passage 115 connected in parallel, and the three parts merge at the upstream end of the outlet tube 112. Figure 2 As shown, when the flowmeter is working, the fluid enters the expansion section 113 from the liquid inlet 111 and then first enters the central channel 115. Since the central channel 115 is in an expansion shape from the upstream end to the downstream end, and the inner diameter of the downstream end of the central channel 115 is larger than the inner diameter of the outlet tube 112, some branches will be separated from the fluid flowing downstream from the central channel 115 and enter the first side passage 116 and the second side passage 117 respectively, and merge at the downstream end of the liquid inlet 111 and flow back to the entrance of the central channel 115. The fluid in the central channel 115 forms a pulse jet, and the pulse flow ejected from the outlet tube 112 impacts the vibration rod to generate vibration. The sensor device 40 collects the vibration signal to achieve flowmeter measurement.

[0020] 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.

[0021] 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 .

[0022] 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.

[0023] The flow meter of the present invention can be used on a water meter or a gas meter. Preferably, an independent shell that can accommodate the electronic components of the smart water meter or gas meter is attached to the outside of the shell of the opening and closing valve 21. The shell is provided with a liquid crystal display device such as an LCD display to indicate water usage information such as the operating status of the water meter or gas meter, and a communication device for providing information to a remote management system is provided in the cavity of the shell.

[0024] When used as a smart water meter, the signal lines of the vibrating rod 30 and the sensor device 40 of the present invention are connected to the electronic circuit, and the working status of the vibrating rod 30 and the sensor device 40, and the information of the water flow flowing through the water meter can be monitored by electronic components. Through the control of the electronic circuit, the sensor device and the built-in operating software, the information such as the water flow speed and flow rate in the pipeline, whether the pipeline is leaking, whether the pipeline is overloaded, whether the water meter is working, etc. can be collected and displayed on the liquid crystal display, and provided to the remote meter reading system through wired or wireless communication.

Claims

1. A flow meter, characterized in that: The downstream end of the liquid inlet pipe (1) is connected to the inner cavity of a tube box-shaped meter case (3); a flow guide pipe (22) is arranged in the chamber of the meter case (3); a reduced diameter section (221) is arranged in the midstream section of the flow guide pipe (22); 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 meter case (3) and the upstream end of the flow guide pipe (22) are closed or connected. A pulse jet (11) is arranged on the tube wall of the flow guide tube (22); a liquid inlet (111) of the pulse jet (11) is connected to the inner cavity of the watch case (3); a jet of the pulse jet (11) is directed toward a free end or a section of a vibration rod (30) arranged in the flow guide tube (22); a sensor device (40) is arranged on the shell wall of the watch case (3) near the free end of the vibration rod (30); the sensor device (40) collects a vibration signal of the vibration rod (30) and outputs the collected vibration signal.

2. The flow meter 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).

3. The flow meter according to claim 1, characterized in that: The middle section of the vibration rod (30) is located in the reduced diameter section (221).

4. The flow meter according to claim 1, characterized in that: The pipe section between the liquid inlet (111) and the outlet tube (112) of the pulse ejector (11) is an expanded diameter section (113). The inner cavity of the expanded diameter section (113) is provided with two diverter blocks (114) symmetrically arranged relative to the tube core line of the expanded diameter section (113). A first side passage (116) and a second side passage (117) are formed between the diverter blocks (114) and the tube wall of the expanded diameter section (113). A central channel (115) is formed between the two diverter blocks (114). The first side passage (116), the second side passage (117) and the central channel (115) form a parallel channel. The central channel (115) is expanded from the upstream end to the downstream end, and the inner diameter of the downstream end of the central channel (115) is larger than the inner diameter of the outlet tube (112).

5. The flow meter 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).

6. The flow meter according to claim 2, characterized in that: The rod core line of the vibration rod (30) coincides with the tube core line of the flow guide tube (22).

7. The flow meter 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 flow meter 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).

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