CN111811622A - A magnetic levitation float flowmeter - Google Patents

Abstract

The invention discloses a magnetic suspension type float flowmeter. The existing rotameter generally has the problem of the lower measurement limit. The present invention includes a vertically disposed metering tube and a float disposed within the metering tube. A cylindrical magnetic steel is arranged in the float or at the bottom of the float, and the magnetic poles of the magnetic steel are arranged up and down; a reflective cone is arranged on the top of the float, and the side surface of the cone is a reflective surface. A magnetic steel ring is arranged outside the measuring tube, and the magnetic force line of the central axis of the magnetic steel ring is opposite to the magnetic force line of the magnetic steel. A laser transmitter is arranged in the measuring tube, a photosensitive position sensor is arranged outside the measuring tube corresponding to the position of the float, and the photosensitive position sensor is connected to the position signal data processing unit. The invention utilizes the repulsive force of the magnetic field so that the float is already in a suspended state at zero flow, and as long as there is a small flow in the metering tube, the height of the float can be changed and the lower measurement limit is eliminated. At the same time, the present invention has high measurement precision and good stability.

Description

A magnetic levitation float flowmeter

technical field

The invention belongs to the technical field of measurement, and in particular relates to a magnetic suspension type float flowmeter.

Background technique

The float flow meter measures the flow rate of the fluid in the pipeline by measuring the height of the float. When the flow rate increases, the float in the tube moves up, and when the flow rate decreases, the float moves down. When the buoyant force on the float is equal to the weight of the float, the float is in a state of equilibrium. Therefore, the flow rate in the pipe can be measured by measuring the height of the float. There are many ways to measure the height of the float, the easiest is to read directly through the scale on the metering tube. There are also optical and magnetoelectric methods to obtain float height data.

Since the float has a certain gravity, the flow rate of the fluid must reach a certain value, so that the float can only float when the buoyancy of the float exceeds the gravity of the float. Therefore, the flow rate that the rotameter can test has a lower limit, which is generally about 5 times the pressure loss. Assuming that the pressure difference before and after the float in a flowmeter tube is 7kPa, the minimum flow rate that the flowmeter can measure is 35kPa. That is, it is difficult for a rotameter to measure a flow whose flow is less than a certain limit value.

In order to reduce the limit value, the general method is to design the metering tube into a tapered tube to improve the upward buoyancy of the float, such as the utility model patent with the patent number of 200820206788.1 and the name "Magnetic Rollover Column Rotameter". There are also other methods, such as the patent number 201920360517.X, the name is "a direct reading throttling flowmeter", which adopts parallel and parallel main pipes and transparent measuring tubes. There is a water passage on the dividing plate, which divides the main pipe into a high-pressure area and a low-pressure area, and the two ends of the metering tube are respectively connected to the high-pressure area and the low-pressure area, so that the upward buoyancy of the float can be increased.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a magnetic suspension type float flowmeter, which can measure a very small flow, in view of the problem that the existing float flowmeter has a lower measurement limit.

The present invention includes a vertically disposed metering tube and a float disposed within the metering tube.

The measuring tube is a transparent tube, and the two ends of the measuring tube are fixedly connected with flanges;

The float is movably arranged in the metering tube and can move up and down along the metering tube; a cylindrical magnetic steel is arranged in the float or at the bottom of the float, and the magnetic poles of the magnetic steel are arranged up and down; the top of the float is arranged with a reflective cone, which is a cone, The central axis section of the cone is an isosceles triangle with a base angle of 45 degrees, and the side of the cone is a reflective surface;

A magnetic steel ring is arranged outside the measuring tube, the magnetic steel ring is sleeved outside the measuring tube, and is fixedly installed at the lower part of the measuring tube near the flange;

The measuring tube is provided with a laser emitter, the laser emitter is arranged on the upper part of the measuring tube, and the emitted light beam is parallel to the central axis of the measuring tube;

A photosensitive position sensor is arranged outside the measuring tube corresponding to the position of the float, and the photosensitive position sensor is connected to the position signal data processing unit.

Further, the measuring tube is a tapered tube with a smaller inner diameter and a larger inner diameter.

Since the magnetic pole of the inner ring of the magnetic steel ring and the lower magnetic pole of the magnetic steel have the same polarity, the generated constant repulsive force suspends the magnetic steel together with the float at a certain position in the metering tube, and when the fluid with a small flow passes through the float, the float can be pushed upward. .

Due to the use of a magnetic levitation float, in order to avoid magnetic interference, the data cannot be read by magnetic force. At the same time, for accurate and convenient reading, optical reading is adopted. The laser emitted vertically downward by the laser transmitter is reflected by the reflective surface of the reflective cone to form a horizontal beam. When the float moves up and down, the horizontal beam moves in the vertical direction accordingly. The photosensitive position sensor receives the signal of the beam and sends it to the position signal data processing unit to obtain the height information of the float. After processing, it is converted into flow for display or remote. to the 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 flow meter can be improved. The reception of the light beam signal by the photosensitive position sensor and the processing of the information by the position signal data processing unit are mature prior art, and have nothing to do with the problem of eliminating the measurement lower limit of the flowmeter to be solved by the present invention.

The invention utilizes the repulsive force of the magnetic field to make the float already in a suspended state at zero flow rate, and as long as there is a small flow rate in the metering tube, the height of the float can be changed, so that the lower measurement limit is greatly expanded downward; at the same time, a photosensitive position sensor is used to measure the float The change in height further improves the accuracy of float height measurement. In addition, the data output by the photosensitive position sensor can be further processed, which can filter out measurement errors caused by factors such as float vibration.

Description of drawings

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

Detailed ways

As shown in FIG. 1 , a magnetic levitation type float flowmeter includes a vertically arranged measuring tube 1 and a float 2 arranged in the measuring tube.

The measuring tube 1 is a tapered tube with a transparent inner diameter that is smaller at the lower end and larger at the upper end. The two ends of the measuring tube 1 are fixedly connected with a flange 3. The flange 3 is used to connect the flowmeter in series on the pipeline 1 that needs to measure the flow. The lower end of the metering tube 1 is the fluid inlet, the upper end is the fluid outlet, and the direction of the hollow arrow in the figure is the fluid flow direction.

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

A magnetic steel ring 6 is arranged outside the measuring tube 1, and the magnetic steel ring 6 is sleeved outside the measuring tube 1, and is fixedly installed at the lower part of the measuring tube 1 near the flange 3; The magnetic poles are of the same polarity.

A laser transmitter 7 is arranged in the metering tube 1 , the laser transmitter 7 is arranged on the upper part of the metering tube 1 , and the emitted light beam is parallel to the central axis of the metering tube 1 .

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

Since the magnetic field lines of the central axis of the magnetic steel ring are opposite to the magnetic field lines of the magnetic steel, the generated repulsive force suspends the magnetic steel 4 together with the float 2 at a certain position in the metering tube 1, and the fluid with a small flow rate can be pushed through the float 2. Float 2 goes up. The magnetic steel ring 6 biases the center of gravity of the float to the bottom of the float to improve the stability of the float. The cylindrical magnetic steel on the float and the magnetic steel ring 6 at the lower part of the metering tube have opposite polarities on the axis, so a repulsion force is generated to make the float levitate, and It can ensure that the float moves in the direction of the central axis.

In the direction of the arrow in Figure 1, the beam emitted by the laser transmitter 7 is irradiated on the 45-degree angle reflective cone above the float. The reflected laser beam is 90 degrees from the original beam, and is directed to the photosensitive position sensor 8 outside the flow tube. The position of the laser spot on the photosensitive position sensor 8 is related to the height of the float. The greater the flow rate, the higher the float position, and the higher the position of the light spot on the photosensitive position sensor 8. Conversely, the smaller the flow rate, the lower the float position, and the lower the position of the light spot on the photosensitive position sensor 8. Therefore, the photosensitive position sensor 8 can determine the height of the float according to the position of the laser spot. When there is no fluid flow in the metering tube 1, the float is in a position where the magnetic field repulsion and gravity balance, and the height of the laser spot position corresponding to the photosensitive position sensor 8 at this time is set to 0, which is the 0 flow position. When there is fluid flowing in the flow tube, even a small flow can cause the height of the float to change because the weight of the float itself has been canceled by the repulsive force of the magnetic field. The photosensitive position sensor 8 outputs a signal to the position signal data processing unit 9 according to the position of the laser spot, and calculates the corresponding flow according to the height data of the float for display or remote transmission to the monitoring room.

The float flowmeter has the following advantages:

1. The repulsion between the magnetic steel and the magnetic ring is used to offset the gravity of the float, which eliminates the problem that the lower limit of the float flowmeter is not 0, so that the lower limit of the float flowmeter can be extended down to 0; 2. The photosensitive position sensor is used to read Taking the height of the float, it has the characteristics of high precision and small error, and the accuracy of the corresponding flowmeter is also improved; 3. Because the conical reflective cone is used to reflect the laser light, even if the float rotates and shakes during use, the laser beam can still be transmitted. It is reflected into the position-sensitive sensor, and the stability of the flowmeter is improved by means of accumulating and averaging the position data.

Claims (2)

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.

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