JPH0530203B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic flow rate measuring device, and an object thereof is to be able to stably measure the flow rate of a fluid in a pipe line over a long period of time.

Impeller type flowmeters, differential pressure type flowmeters, vortex flowmeters, electromagnetic type flowmeters, etc. have been developed as means for measuring fluid flow rates in water and sewerage pipes, etc., and impeller type flowmeters are particularly popular. However, because it has a mechanical structure with moving parts, it suffers from frequent failures such as wear and loss, is unstable in operation at low flow speeds, and has the disadvantages that installation work to existing pipes is time-consuming. Exists.

Therefore, electromagnetic flowmeters with excellent accuracy are used as flowmeters that achieve the desired effect.

As is well known, an electromagnetic flowmeter applies a magnetic field perpendicularly to a pipe through which an electrically conductive fluid flows, and provides electrodes facing the pipe wall in a direction perpendicular to the direction of the magnetic field and the direction of fluid flow. The configuration is such that the flow rate is determined by measuring the voltage generated between the electrodes due to electromagnetic induction.

However, when measuring the flow rate in a pipe, this type of flowmeter is attached to the outside of the pipe, so it is structurally large, and in the case of an electromagnet, it has a special shape, so it cannot be molded. There were some dissatisfied points such as increased cost.

In addition, accurate measurements cannot be obtained unless the pipe at the measurement point is made of non-magnetic material, so if it is installed on an existing pipe, it will be necessary to partially replace the pipe.
It also has the disadvantage of poor workability.

In other words, when conventional electromagnetic flowmeters are installed in a fluid pipeline, it is necessary to select a model with an appropriate size according to the diameter of the pipeline, so many models must be prepared. Inevitably, large-diameter pipes require increased size, weight, and cost, and require the introduction of machinery for installation work, which makes handling difficult and reduces work efficiency. If the device is large-scale, it will consume a lot of power, making it uneconomical.

In addition, when installing any type of equipment, including impeller type and electromagnetic type, into existing pipes, it is necessary to cut off the water supply and cut the pipe, and during maintenance inspections, etc., it is necessary to cut off the water supply or use a pre-installed bypass pipe. Therefore, the construction itself would have to be large-scale. The most reliable means of calibrating an electromagnetic flowmeter is actual flow rate calibration, but even when installed in this actual flow rate calibration device,
It is necessary to prepare a flowmeter of a scale corresponding to the pipe diameter to be used, and furthermore, the flow velocity sensitivity of conventional flowmeters is about 0.3 m/sec or more, and the accuracy for low flow velocity below this value is poor. I regret not being able to get it.

In other words, conventional flowmeters had drawbacks and inconveniences in all respects in terms of workability, economy, and accuracy.

The present invention relates to an electromagnetic flow rate measuring device developed in view of the above-mentioned conventional drawbacks and inconveniences, and is configured so that it can be easily installed in existing pipes and can provide high accuracy.

An embodiment of the present invention will be described below with reference to the drawings.

First, reference numeral 1 in the figure is the main body of the current meter.

The current meter main body 1 has a streamlined shape in which a core 3 around which an electromagnetic coil 2 is wound and an electrode 5 are integrated by a resin mold 7, and a guide groove 8 is formed in the center of both sides along the front-rear direction. A holding rod 9 is integrally protruded from the center of the upper end.

Inside the main body 1, a yoke 4 is integrally provided with both magnetic poles at both upper and lower ends of the core 3, which is vertically aligned in the same direction as the holding rod 9.

The yoke 4a at the upper end extends downward on both sides, and the yoke 4b at the lower end extends upward on both sides.
The tip of the yoke 4a at the upper end and the tip of the yoke 4b at the lower end are close to each other and face each other with a length interval that is approximately the same as the width of the guide groove 8. A pair of magnetic paths A are formed perpendicularly along the direction.

The two electrodes 5 are located between the two magnetic paths A, and are provided in the center of the guide groove 8 with a portion exposed to the outside, and a neutral electrode 6 is located at the exposed position at the front end of the main body 1. are doing.

Incidentally, the lead wires of the electromagnetic coil 2 and the electrodes 5 and 6 are led out through the holding rod 9.

The above-described current meter main body 1 is installed and fixed in a pipe line 10 of a water supply or the like, and its posture is along the flow path with the front end facing upstream of the fluid.

Now, in the above-mentioned measuring device, the electromagnetic coil 2
is excited by a low frequency rectangular wave method using a commercial power source, battery, dry cell, etc., and magnetic paths A are formed between the yokes 4 on both sides of the main body 1, respectively.

Then, the induced voltage generated when the conductive fluid flowing from the front end to the rear end of the guide grooves 8 on both sides of the main body 1 passes orthogonally to the magnetic path A is detected by both electrodes 5, and the flow velocity of the fluid is measured. In particular, the flow rate is measured.

In this case, since the magnetic poles of the magnetic path A face each other with a small width due to the yoke 4, the magnetic path A is formed and converged in a short range, and the magnetic field does not expand, and the conduit 10 itself Regardless of whether it is made of magnetic material or non-magnetic material, the magnetic path A is hardly affected, and extremely accurate measurements can be achieved.

Furthermore, the tips of the yokes 4, which are the tips of both magnetic poles, are opposed to each other across the guide groove 8, and the fluid flows from the front end to the rear end of the guide groove 8, so that the shortest linear distance between the two magnetic poles is Moreover, as mentioned above, since both electrodes 5 are exposed in the guide groove 8 portion, it is possible to reduce the size and consume less power. without being affected by
It enables highly accurate detection.

Fig. 5 is a graph showing the accuracy of the present invention. Here, it shows the flow velocity results in meters per second in a magnetic tube with an inner diameter of 100 mm. The horizontal axis is the actual velocity value, and the vertical axis is the actual velocity value. The value indicated by the main body 1 is taken as the indicated value on the axis.

From this test data, it will be understood that the measured value of the main body 1 is extremely linear with respect to the actual speed. Figure 5b is an enlargement of the part with particularly low flow velocity.
The numbers here are also extremely linear, 0.005m/
The data has been verified up to the sec value.

That is, in the present invention, in addition to locally increasing the density of the magnetic path A by attaching the yoke 4, since a low frequency rectangular wave excitation method is adopted, the measurement accuracy in the small flow velocity region of the fluid is also improved. This is extremely high. This is evidenced by the fact that the data shown in FIG. 5 is linear even though it is based on a tube made of magnetic material.

Further, since the structure is simple, it has the advantage that it can be easily attached to a conduit.

The embodiment shown in FIG. 4 shows a state in which it is assembled into an existing pipe line 10. Here, the main body 1 is connected to a part of the pipe line 10 via a gate valve 11, a gland flange 12, etc.
Attach the flow direction indicator handle 1 to the upper end of the main body 1.
Connect to 3. By operating the handle 13, the attitude of the main body 1 is controlled in accordance with the flow direction within the conduit 10.

Furthermore, it is also possible to use the device of the present invention to check the accuracy of a conventional existing current meter by attaching the main body 1 to the air vent of the existing conduit 10 exposed on the bridge side, or by simply assembling and fixing the device itself. This may be done using the air bleed mentioned above. That is, the device here can be implemented either permanently or temporarily.

Therefore, according to the electromagnetic flow rate measuring device of the present invention,
It can be easily installed into existing pipes regardless of the material, has extremely high accuracy, and has no moving parts, so there is no problem such as wear due to fluids or failures, and stable measurement can be performed over a long period of time. is easy and
It has many excellent functions and effects, such as being small, highly workable, and inexpensive.

[Brief explanation of the drawing]

Fig. 1 is a side view showing one embodiment of the current meter main body of the present invention, Fig. 2 is a side sectional view, Fig. 3 is a front sectional view, Fig. 4 is a sectional view of the flowmeter installed in a pipe, and 5
The figure is a graph showing the accuracy of the main body in the present invention. Explanation of symbols: 1... current meter body, 2... electromagnetic coil, 3... core, 4... yoke, 5, 6... electrode, A... magnetic path.

Claims (1)

[Claims] 1 Guide grooves are provided along the liquid flow path on both sides of the resin-molded current meter body, and both magnetic poles of the core around which the electromagnetic coil is wound are inserted into the inside of the current meter body through a yoke. By arranging them in close and opposing positions, a pair of magnetic paths orthogonal to the guide groove, which is a fluid flow path, is formed, and furthermore, within the pair of magnetic paths, a pair of magnetic paths are placed in positions perpendicular to the flow path and the magnetic path. An electromagnetic current velocity measuring device comprising: an electromagnetic current meter having an electrode exposed in the guide groove portion; and an electromagnetic current meter disposed within a fluid conduit.