CN111811622A

CN111811622A - Magnetic suspension float flowmeter

Info

Publication number: CN111811622A
Application number: CN202010489560.3A
Authority: CN
Inventors: 季振国; 李阳阳; 毛启楠
Original assignee: Hangzhou Dianzi University
Current assignee: Hangzhou Dianzi University
Priority date: 2020-06-02
Filing date: 2020-06-02
Publication date: 2020-10-23

Abstract

The invention discloses a magnetic suspension float flowmeter. The problem of measurement lower limit exists universally in the existing float flowmeter. The invention comprises a vertically arranged metering tube and a float arranged in the metering tube. Cylindrical magnetic steel is arranged in the floater or at the bottom of the floater, and magnetic poles of the magnetic steel are arranged up and down; the top of the floater is provided with a light reflecting cone, and the side surface of the cone is a light reflecting surface. The measuring tube is sleeved with a magnetic steel ring, and the magnetic line of force of the central axis of the magnetic steel ring is opposite to the magnetic line of force of the magnetic steel. A laser emitter is arranged in the metering tube, a photosensitive position sensor is arranged outside the metering tube corresponding to the position of the floater, and the photosensitive position sensor is connected with a position signal data processing unit. The invention uses the repulsion force of the magnetic field to make the floater in the suspension state when the flow is zero, and the height of the floater can be changed as long as the flow in the metering pipe is very small, thereby eliminating the lower limit of measurement. Meanwhile, the invention has high measurement precision and good stability.

Description

Magnetic suspension float flowmeter

Technical Field

The invention belongs to the technical field of metering, and particularly relates to a magnetic suspension type float flowmeter.

Background

Float flowmeters measure the flow rate of fluid in a conduit by measuring the height of a float. The float in the tube moves upward when the flow increases, whereas it moves downward when the flow decreases. When the buoyancy force borne by the floater is equal to the gravity of the floater, the floater is in a balanced state. Thus, the amount of flow in the pipe can be measured by measuring the height of the float. There are several ways to measure the height of the float, the simplest being direct reading through a scale on the metering tube. And the data of the height of the floater can be acquired by adopting optical and magnetoelectric modes.

Because the float has a certain gravity, the flow rate of the fluid must reach a certain value, so that the float can float only when the buoyancy force applied to the float exceeds the gravity of the float. Thus, float flowmeters can measure a lower limit of flow, typically around 5 times the pressure loss. Assuming that the pressure difference across the float in a certain flow meter tube is 7kPa, the minimum measurable flow rate of the flow meter is 35 kPa. That is, float flowmeters have difficulty measuring flow rates below a certain limit.

To reduce this limit, it is common to design the metering tube as a tapered tube to increase the upward buoyancy of the float, as disclosed in the utility model entitled "magnetic tumble rotameter," having patent number 200820206788.1. Other methods are also adopted, such as the patent number of 201920360517.X, which is named as a direct-reading throttling flowmeter, a main pipe and a transparent metering pipe which are parallel are adopted, a floater is arranged in the metering pipe, a partition plate is arranged in the main pipe, a water through hole is formed in the partition plate, the main pipe is divided into a high-pressure area and a low-pressure area, and two ends of the metering pipe are respectively connected with the high-pressure area and the low-pressure area, so that the upward buoyancy of the floater can be increased.

Disclosure of Invention

The invention aims to provide a magnetic suspension float flowmeter which can measure very small flow aiming at the problem of lower measurement limit of the existing float flowmeter.

The invention comprises a vertically arranged metering tube and a float arranged in the metering tube.

The metering tube is a transparent tube, and two ends of the metering tube are fixedly connected with flange plates;

the floater is movably arranged in the metering pipe and can move up and down along the metering pipe; cylindrical magnetic steel is arranged in the floater or at the bottom of the floater, and magnetic poles of the magnetic steel are arranged up and down; a light reflecting cone is arranged at the top of the floater, the light reflecting cone is a cone, the section of the central shaft of the cone is an isosceles triangle with a bottom angle of 45 degrees, and the side surface of the cone is a light reflecting surface;

the magnetic steel ring is sleeved outside the metering pipe and fixedly arranged at the lower part of the metering pipe close to the flange; the magnetic line of force of the central axis of the magnetic steel ring is opposite to the magnetic line of force of the magnetic steel.

The laser emitter is arranged on the upper part of the metering tube, and emitted light beams are parallel to the central axis of the metering tube;

and a photosensitive position sensor is arranged outside the metering tube corresponding to the position of the floater and is connected with a position signal data processing unit.

Furthermore, the metering pipe is a taper pipe with a small inner diameter at the lower part and a large inner diameter at the upper part.

Because the inner ring magnetic pole of the magnetic steel ring and the magnetic pole at the lower part of the magnetic steel are homopolar, the magnetic steel and the floater are suspended at a certain position in the metering pipe by the generated constant repulsive force, and the floater can be pushed to move upwards by fluid with small flow when the fluid passes through the floater.

Because the magnetic suspension type floater is adopted, the data can not be read in a magnetic manner for avoiding magnetic interference, and meanwhile, an optical reading manner is adopted for reading accurately and conveniently. The laser emitted vertically downwards by the laser emitter is reflected by the reflecting surface of the reflecting cone to form a horizontal light beam. When the floater moves up and down, the horizontal light beam correspondingly moves in the vertical direction, the photosensitive position sensor receives the signal of the light beam and sends the signal to the position signal data processing unit, so that the height information of the floater can be obtained, and the height information is processed and then converted into flow to be displayed or transmitted to a monitoring room. In order to suppress the influence of float shaking on the flow reading, the position signal data processing unit can accumulate and average the position data within a set time, so that the stability of the flowmeter is improved. The photosensitive position sensor receives the light beam signals and the position signal data processing unit processes the information, which are mature prior art and have no relation with the problem of eliminating the lower limit of the flowmeter measurement to be solved by the invention.

The invention utilizes the repulsion force of the magnetic field to lead the floater to be in a suspension state when the flow is zero, and the height of the floater can be changed as long as the flow in the metering pipe is very small, thus leading the lower limit of the measurement to be greatly expanded downwards; and meanwhile, the photosensitive position sensor is adopted to measure the height change of the floater, so that the accuracy of the height measurement of the floater is further improved. In addition, the data output by the photosensitive position sensor can be further processed, and measurement errors caused by factors such as floater vibration can be filtered out.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

Detailed Description

As shown in fig. 1, a magnetic suspension float flowmeter includes a vertically disposed metering tube 1 and a float 2 disposed in the metering tube.

The measuring pipe 1 is a transparent taper pipe with a small inner diameter at the bottom and a large inner diameter at the top, the two ends of the measuring pipe 1 are fixedly connected with flange plates 3, and the flange plates 3 are used for connecting the flowmeter in series on a pipeline I needing to measure flow. Wherein the lower end of the metering pipe 1 is a fluid inlet, the upper end is a fluid outlet, and the hollow arrow direction in the figure is the fluid flow direction.

The floater 2 is movably arranged in the metering pipe 1 and can move up and down along the metering pipe 1; a cylindrical magnetic steel 4 is arranged in the floater 2 or at the bottom of the floater 2, and the magnetic poles of the magnetic steel 4 are arranged up and down; the top of the floater 2 is provided with a light reflecting cone 5, the light reflecting cone 5 is a cone, the section of the central shaft of the cone is an isosceles triangle with a bottom angle of 45 degrees, and the side surface of the cone is a light reflecting surface.

A magnetic steel ring 6 is arranged outside the metering pipe 1, and the magnetic steel ring 6 is sleeved outside the metering pipe 1 and fixedly arranged at the lower part of the metering pipe 1 close to the flange 3; the inner ring magnetic pole of the magnetic steel ring 6 and the lower magnetic pole of the magnetic steel 4 are homopolar.

A laser emitter 7 is arranged in the metering tube 1, the laser emitter 7 is arranged on the upper portion of the metering tube 1, and emitted light beams are parallel to the central axis of the metering tube 1.

A photosensitive position sensor 8 is arranged outside the metering tube 1 corresponding to the position of the floater 2, and the photosensitive position sensor 8 is connected with a position signal data processing unit 9.

Because the magnetic line of force of the central axis of the magnetic steel ring is opposite to the magnetic line of force of the magnetic steel, the generated repulsion suspends the magnetic steel 4 and the floater 2 at a certain position in the metering tube 1, and the fluid with small flow can push the floater 2 to move upwards when passing through the floater 2. The magnetic steel ring 6 makes the gravity center of the floater incline to the bottom of the floater to improve the stability of the floater, and the cylindrical magnetic steel on the floater and the magnetic steel ring 6 at the lower part of the metering tube have opposite polarities on the axis, so that repulsive force is generated to make the floater suspend, and the floater can be ensured to move along the direction of the central axis.

As shown in the arrow direction of figure 1, a light beam emitted by a laser emitter 7 irradiates on a 45-degree reflection cone above the floater, and a reflected laser beam forms an angle of 90 degrees with an original light beam and emits to a photosensitive position sensor 8 outside the flow pipe. The position of the laser spot at the light-sensitive position sensor 8 is related to the height of the float. The higher the flow, the higher the float position and the higher the position of the light spot on the light-sensitive position sensor 8. Conversely, the smaller the flow, the lower the float position and the lower the position of the light spot on the light-sensitive position sensor 8. Thus, the light-sensitive position sensor 8 can determine the height of the float from the position of the laser spot. When no fluid flows in the metering tube 1, the floater is in a position where magnetic field repulsive force and gravity are balanced, and the height of the laser spot position corresponding to the photosensitive position sensor 8 at the moment is set to be 0, namely the 0-flow position. When fluid flows in the flow pipe, even a small flow rate can cause the height of the float to change because the weight of the float is offset by the repulsive force of the magnetic field. The photosensitive position sensor 8 outputs signals to the position signal data processing unit 9 according to the laser spot position, and calculates corresponding flow according to the height data of the floater to display or remotely transmit the flow to the monitoring room.

The float flowmeter has the following advantages:

1, the repulsive force between the magnetic steel and the magnetic ring is utilized to offset the gravity of the floater, so that the problem that the lower limit of the measurement of the floater flowmeter is not 0 is solved, and the lower limit of the floater flowmeter can be expanded to 0 downwards; 2, the height of the floater is read by adopting a photosensitive position sensor, so that the device has the characteristics of high precision and small error, and the precision of a corresponding flowmeter is improved; 3, because the conical reflecting cone is adopted to reflect the laser, even if the floater rotates and shakes during the use, the laser beam can still be reflected to the position sensitive sensor, and the stability of the flowmeter is improved by means of averaging after the position data are accumulated.

Claims

1. A magnetic suspension float flowmeter comprises a metering pipe (1) which is vertically arranged and a float (2) which is arranged in the metering pipe; the method is characterized in that:

the metering tube (1) is a transparent tube, and two ends of the metering tube (1) are fixedly connected with flange plates (3);

the floater (2) is movably arranged in the metering pipe (1) and can move up and down along the metering pipe (1); cylindrical magnetic steel (4) is arranged in the floater (2) or at the bottom of the floater (2), and magnetic poles of the magnetic steel (4) are arranged up and down; a light reflecting cone (5) is arranged at the top of the floater (2), the light reflecting cone (5) is a cone, the section of the central shaft of the cone is an isosceles triangle with a bottom angle of 45 degrees, and the side surface of the cone is a light reflecting surface;

the magnetic steel ring (6) is arranged outside the metering pipe (1), and the magnetic steel ring (6) is sleeved outside the metering pipe (1) and fixedly arranged at the position, close to the flange plate (3), of the lower part of the metering pipe (1); the magnetic line of force of the central axis of the magnetic steel ring (6) is opposite to the magnetic line of force of the magnetic steel (4);

a laser emitter (7) is arranged in the metering tube (1), the laser emitter (7) is arranged at the upper part of the metering tube (1), and emitted light beams are parallel to the central shaft of the metering tube (1);

the device is characterized in that a photosensitive position sensor (8) is arranged outside the metering tube (1) and corresponds to the position of the floater (2), and the photosensitive position sensor (8) is connected with a position signal data processing unit (9).

2. The magnetic levitation type float flowmeter as claimed in claim 1, wherein: the metering tube (1) is a taper tube with a small inner diameter at the bottom and a large inner diameter at the top.