JPS6226407B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention improves the method of floating a float inside a pipe and measuring the flow rate based on the amount of displacement of the float caused by the flow of fluid, and converts the displacement of the float into the strength of a magnetic field to measure the flow rate. It concerns the method of measurement.

Float-type flowmeters are simple, but they have problems such as the amount of displacement of the float being read using a scale installed on the pipe wall, which tends to cause individual differences in visual measurements and can only measure approximate values. However, accurate measurements cannot be expected.

Therefore, by utilizing the principle of a differential transformer, a magnetic float is built into the fluid pipe, an excitation coil for attraction is provided surrounding the fluid pipe, and coils forming a differential transformer are installed before and after the excitation coil. The arranged flowmeter is disclosed in Japanese Utility Model Publication No. 49-41329. The system disclosed in this publication uses the scale on the pipe wall to read the displacement of the float placed in the center of the excitation coil due to the flow when the flow velocity is zero, based on changes in the electromotive force of the differential transformer. Although this method is more accurate than one that is read by hand, it has a complicated structure because it uses three sets of coils, and it also has the disadvantage that if the float moves beyond the restoring force of the excitation coil's magnetic force, it will be washed away.

The present invention provides a method that can electrically measure the flow rate accurately without worrying about the float being washed away with a simple configuration using a single electromagnetic coil, and in which the pipe line through which the fluid flows is arranged vertically. Then, an electromagnetic coil is installed surrounding this pipe, and a float that repels the magnetic field created by this electromagnetic coil is built into the pipe and floats, and when the float is displaced by the flow in the pipe, it is supplied to the electromagnetic coil. The feature is that the float is returned to the zero flow position by changing the current and the strength of the magnetic field, and the flow rate of the fluid is measured based on the amount of change in current.

Embodiments of the present invention will be described below with reference to the drawings. In FIGS. 1 and 2, 1 is a pipe line arranged vertically, and 2 is a pipe made of a magnet, has a magnet in a part, or is made of a magnetic material. A conical float made of A flow rate display meter that converts and displays the flow rate of fluid is shown.

Figure 1 shows the case where the weight of the float 2 built into the pipe 1 is greater than the buoyant force, and when there is no flow due to repulsion to the magnetic field created by the electromagnetic coil 3, the weight F _g buoyant force F _b and the magnetic force F _n are balanced. The float 2 is floating and stationary above the electromagnetic coil 3. In this state, the force F that the float 2 receives is F=F _g +F _b +F _n =0. When an upward flow is generated in the pipe 1 as shown by arrow A, the float 2 receives an upward force F _f due to this flow, F=F _f =F _g +F _b +F _n (however, F _f <F ) and stops. When the current regulator 5 is operated to apply a force ΔF of ΔF=F _n −F _f by changing the strength of the magnetic field by the electromagnetic coil 3, the float 2 is returned to the zero flow position. Therefore, the flow rate is determined by reading or recording the flow rate value corresponding to the current required to create this force ΔF, that is, the amount of change in current from the current when the flow rate is zero, using the flow rate indicator 6. Even if the float 2 descends from the zero flow rate position, F>0, so it is pulled back to the F=0 position. In this example, when a flow is generated, F
<0, and the float 2 moves away from the electromagnetic coil 1, so the current is decreased and F _n is made smaller, so that F=0.

FIG. 2 shows a case where the buoyancy of the float 2 is greater than its weight, and the float 2 is floating and stationary below the electromagnetic coil 3. When an upward flow is generated in the pipe line 1 as indicated by the arrow A, the float 2 receives an upward force F due to this flow and rises to a position where F=F _f and approaches the electromagnetic coil 3. Because it stops,
A force ΔF of ΔF=F _n −F _f is applied to return the float 2 to the position of zero flow rate. In this example, when a flow is generated, F > 0, the current is increased, F _n is increased, and F = 0.The value of the flow rate corresponding to the current value required to create this force △F is The flow rate is known by reading or recording it with the flow rate indicator 6.

Here, F _g and F _b are given as initial conditions by the volume and weight of the float 2 and the specific gravity of the fluid, and if the fluid flow is uniform, they show constant values, so a force of △F is created. By measuring the current value required to change the strength of the magnetic field, the magnitude of F _f can be determined, and ultimately the flow rate can be determined accurately.

For instantaneous flow rate changes such as pulsating flow, a scale may be provided on the pipe wall and the instantaneous displacement of the float 2 may be visually measured to determine the flow rate.

Furthermore, in the present invention, when the current applied to the electromagnetic coil 3 is determined, the magnetic force F _n is determined, and the position of the float 2 when the flow rate is zero is determined.
The flow rate can be controlled within a certain range by setting the upper and lower limits of the flow rate, sensing when the float 2 moves to the upper and lower limits, and providing feedback to the pump and flow control valve. Further, an ammeter may be used instead of the flow rate indicator 6, and the current may be converted into a flow rate using a conversion table. Furthermore, the portion of the pipe line 1 on which the float 2 floats is not limited to a straight pipe, but may be a tapered pipe that expands upward.

As described above, according to the present invention, an electromagnetic coil is installed surrounding a vertically arranged pipe line, and the float is repelled by the magnetic field created by this electromagnetic coil, and the float is moved by the flow from the position when the fluid flow rate is zero. When the float is displaced, the strength of the magnetic field is changed to return the float to the zero flow position, and the flow rate is measured by the amount of change in the current applied to the electromagnetic coil at this time, so a scale is provided on the pipe wall and the float It does not have the drawbacks of a conventional rotary flowmeter that directly reads the displacement of the flowmeter, such as the inability to measure accurately due to individual differences. In addition, there is no need to perform special processing such as installing orifices or blades in the conduit, and it is only necessary to incorporate a magnetic float and install one electromagnetic coil on the outside, making the configuration extremely simple. The weight and buoyancy of the float given by the conditions are given as constant values if the flow is uniform in a vertical pipe, so they can be accurately determined by a simple operation of changing the strength of the magnetic field to counteract the displacement of the float due to the flow. Not only is it possible to measure the flow rate, but because the strength of the magnetic field is changed to return the float to the zero flow position, it can be handled even at large flow rates without worrying about the float being washed away. Furthermore, the present invention has a wide range of applications, such as being able to record the flow rate or control the flow rate by changing the current applied to the electromagnetic coil.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing different embodiments of the present invention. 1... Pipeline, 2... Float, 3... Electromagnetic coil,
4...Power supply, 5...Current regulator, 6...Flow rate display meter.

Claims (1)

[Claims] 1 A pipe through which fluid flows is arranged vertically, an electromagnetic coil is installed surrounding this pipe, and a float that repels the magnetic field created by this electromagnetic coil is built into the pipe and floated, and the flow inside the pipe is A flow rate characterized in that when the float is displaced, the current supplied to the electromagnetic coil is changed to change the strength of the magnetic field to return the float to the zero flow position, and the flow rate of the fluid is measured based on the amount of change in current. Measuring method.