JPH0749386Y2 - Flowmeter - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter, and more particularly, to an impeller that is rotated by receiving fluid pressure of a fluid flowing in a flow passage, and is fixed to an upstream side of the impeller in the flow passage. And a rectifying means for generating a swirling flow in the flowmeter.

[0002]

2. Description of the Related Art An impeller that is rotated by receiving fluid pressure of a fluid flowing in a flow path, and is fixed on the upstream side of the impeller in the flow path.
There is a technique disclosed in Japanese Utility Model Laid-Open No. 63-105025 as a flowmeter provided with a rectifying means for generating a swirling flow in a fluid. This flow meter is a flow meter including an impeller rotatably supported in a flow path and rectifying devices fixed on the upstream side and the downstream side of the impeller. The straightening device has a plurality of straightening vanes for generating a swirling flow in the fluid. Each straightening vane is arranged so as to be inclined to the outer peripheral surface of the shaft body. Therefore, the fluid that has flowed through the flow path flows along the flow straightening vanes and becomes a swirling flow at that time. When the swirling fluid rotates the impeller, the permanent magnets provided in the impeller rotate together with the impeller. The change in the magnetic field caused by this rotation is detected by the magnetic sensing means to detect the flow rate of the fluid.

[0003]

However, the above-mentioned conventional flowmeter has the following problems. 63-
In the flow meter disclosed in Japanese Patent No. 105025, it is easier to rotate the impeller by causing a swirling flow in the fluid, but when the flow rate of the fluid is small, the rotation of the impeller is dull and the sensitivity is low. There is. Therefore, it is an object of the present invention to provide a highly sensitive flow meter even when the flow rate of fluid is low.

[0004]

In order to solve the above problems, the present invention has the following configuration. That is, it is provided with an impeller that rotates by receiving the fluid pressure of the fluid flowing in the flow path, and a rectifying unit that is fixed to the upstream side of the impeller in the flow path and that generates a swirling flow in the fluid. In the flowmeter, the plurality of spiral ridges are formed on the upstream end face of the flow straightening means, and the spiral ridges have a cross section in the flow path direction.
It is characterized in that it is formed parallel to the flow path direction. Further, the rectifying means, the upstream end is formed into a conical shape,
The spiral ridge may be formed on the outer surface of the conical end. For example, the shape of the spiral ridge can be an Archimedean spiral shape. Further, the rectifying means is
You may make it fit the front-end | tip part of the said spiral convex line formed in a part of upstream end surface to the spiral concave groove formed in the said flow path inner surface.

[0005]

[Operation] The operation will be described. The rectifying means has a plurality of spiral ridges formed on the end face on the upstream side, and the spiral ridges are formed so as to be parallel to the flow passage direction in a cross section in the flow passage direction, so that even a small flow rate of fluid can be obtained. It is possible to generate a swirling flow by smoothly flowing in a spiral with almost no resistance. In particular, when the upstream end of the rectifying means is formed in a conical shape and the spiral ridge is formed on the outer surface of the conical end,
The length of the spiral ridge can be earned. Further, when the tip end portion of the spiral ridge formed on a part of the upstream end surface of the rectifying means is fitted into the spiral groove formed on the inner surface of the flow passage, the rectifying means can be easily attached. In addition to being reliable, it is possible to prevent lateral leakage between the tip of the spiral ridge and the inner surface of the flow path.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. First, the configuration of the flowmeter of the embodiment will be described with reference to FIG. The flow meter shown in FIG. 1 is a flow meter suitable for measuring the amount of purified water in a water purifier. 12
Reference numerals a and 12b denote casing constituent members, which are made of synthetic resin. The casing constituent members 12a and 12b are
The casing 10 is formed integrally by an adhesive, ultrasonic welding, or the like. The casing 10 has an inflow port 14 and an outflow port 16 opened at the lower end surface thereof, and an inverted U-shaped hollow portion is formed in a fluid passage 18. The flow path 18 has a large diameter on the inflow port 14 side from the midway portion, and has a small diameter on the outflow port 16 side. Water flows in the flow path 18 in a U-shape from the arrow A to the arrow B. Reference numeral 20 denotes an impeller shaft, which is provided so as to project from the inner wall surface of the casing constituent member 12b in the flow path 18 toward the inflow port 14.

Reference numeral 22 is a magnetic detection element (for example, a Hall element) which is an example of detection means, and is arranged inside the hollow of the impeller shaft 20. The magnetic detection element 22 is the impeller shaft 2
It is fixed to the circuit board 24, which is fitted and fixed in the inside of the hollow 0. A connector 32 is connected to the upper end of the circuit board 24 to extract the output signal of the magnetic detection element 22. The magnetic detection element 22 and the circuit board 24 are fixed in the impeller shaft 20, and a synthetic resin (for example, silicone or urethane) 26 is filled in the impeller shaft 20 to prevent the magnetic detection element 22 and the circuit board 24 from getting wet with water. ing. Reference numeral 28 denotes an impeller, which includes a hollow cylindrical portion 30 and a plurality of blades 34 extending in the radial direction from the outer peripheral surface of the cylindrical portion 30. The impeller 28 is rotatably fitted onto the outer peripheral surface of the impeller shaft 20 via a bearing 36.

Reference numeral 38 denotes a magnet, which is fitted in the tubular portion 30 of the impeller 28. The magnet 38 is formed in a ring shape, and the magnetic pole centers of the N and S stations are magnetized at two points on the inner peripheral surface facing each other.
The magnetic detection element 22 is located on the line segment connecting the centers of the N and S magnetic poles, that is, on the magnetic circuit, and the rotation detection accuracy of the magnet 38 is improved. Reference numeral 40 denotes an impeller which is a rectifying means, and the impeller shaft 2
The female taper portion 42 near the inflow port 14 at the lower end of 0 and the inner surface of the flow path 18 (the inclination angle is preferably 45 degrees or less)
It is fixed to. The impeller 40 is formed in a conical shape (preferably an inclination angle of 45 degrees or less) facing the inflow port 14 direction. The shape of the impeller 40 will be described with further reference to FIGS. 2 and 3.

On the outer surface of the tapered tip portion of the impeller 40, a plurality of (four in this embodiment) spiral ridges 44 are provided at equal intervals. The spiral shape of the spiral ridge 44 in the present embodiment is an Archimedes spiral shape when viewed from the front side on the upstream side. In the cross section of the spiral ridge 44 in the direction of arrow A, which is the direction of water flow, the edge 46 in the same direction is formed parallel to the direction of arrow A. The spiral ridge 44 converts the DC water flowing in the direction of the arrow A into a swirling flow, and the swirling flow is rotated by the impeller 28.
It is provided to rotate the impeller 28 by hitting the blade 34 of the. The spiral ridge 44 is not formed in the central portion 48 of the tapered tip portion of the impeller 40. This is for guiding the water flowing from the direction of the inflow port 14 between the spiral ridges 44.

By providing the impeller 40, the blade 3
Since the water acting on 4 is not a direct current but a swirling flow, the blades 3 parallel to the axial direction of the casing 10 as in the present embodiment.
Even with 4, the fluid pressure can be effectively applied. Further, the direction of the fluid pressure acting on the impeller 28 is the direction in which the impeller 28 is rotated, and the force in the thrust direction is minimized, so uneven wear of the impeller 28 and the like can be suppressed. Water can flow between the spiral ridges 44 of the impeller 40. In particular, in this embodiment, the spiral ridge 44
In the cross section in the direction of arrow A, since the edge 46 is formed parallel to the direction of arrow A, direct current is introduced between the spiral ridges 44 without resistance, and the water flows by flowing along the spiral ridges 44. Can be swirled smoothly. Therefore, there is almost no energy loss of water when the DC water is converted into a swirling flow, so that a swirling flow can be efficiently generated even with a small flow rate, and the impeller 2
It is possible to keep the energy given to 8 large. As a result, it becomes possible to improve the detection accuracy and resolution of the flow rate and the like.

Reference numeral 50 denotes a spiral groove, which is recessed in the female taper portion 42 on the inner surface of the flow path 18. A plurality of (4 in this embodiment) spiral recessed grooves 50 are provided corresponding to the spiral ridges 44, and are recessed at equal intervals. The spiral shape of the spiral groove 50 in the present embodiment is an Archimedean spiral shape that matches the spiral ridge 44 of the impeller 40. When the impeller 40 is fixed in the flow path 18, the tips of the spiral ridges 44 are fitted into the corresponding spiral groove 50. By this fitting, the impeller 40
Is easy and secure. Further, as compared with the case where the spiral ridge 44 is not fitted to the inner surface of the female tapered portion 42, it is possible to prevent water from leaking laterally from the spiral water channel formed between the spiral ridges 44. It is possible to reduce the measurement error (within this embodiment, within ± 5%).

Next, the operation of the flowmeter of the embodiment will be described. In the flowmeter having the above configuration, when water flows in from the inflow port 14 in the direction of arrow A, the impeller 40 converts the water flow from direct current to swirl flow, and the swirl flow causes the impeller 28 to rotate around the outer circumference of the impeller shaft 20. . When the impeller 28 rotates, the magnetic pole position of the magnet 38 with respect to the magnetic detection element 22 changes, so that the output signal of the magnetic detection element 22 changes. This output signal is sent to the circuit board 24 and the connector 3
2, sent to a detection circuit (not shown) via the lead wire 52,
The rotation speed of the impeller 28 is detected from the frequency indicating the signal change pattern, and the flow rate is calculated and obtained.

FIG. 4 shows a graph of the frequency F of the output signal of the magnetic detection element 22 with respect to the flow rate Q. In FIG. 4, the characteristics of the flowmeter of the present embodiment are shown in graph X, and the characteristics of the conventional actual measurement 63
The characteristics of the flow meter shown in FIG. 1 when the flow meter of FIG. 1 is provided in place of the impeller 40 are graph Y.
Shown in. As is clear from FIG. 4, the flowmeter of the present embodiment can obtain a large output even with a small flow rate, so that the sensitivity, accuracy, resolution, etc. are remarkably improved.

Although the magnetic detecting element 22 is used as the detecting means in this embodiment, it is also possible to use a reflection type optical sensor composed of, for example, a light emitting diode and a light receiving diode as the detecting means. When the reflection type optical sensor is used, the impeller shaft 20 is formed of a transparent member such as a transparent synthetic resin, and the inner peripheral surface of the tubular portion 30 of the impeller 28 is provided with a reflecting member (for example, the radiant light of the light emitting diode is simply reflected. A) aluminum foil to attach it. In the case of a reflection type optical sensor,
When water flows in, the impeller 40 converts the water flow from a direct current to a swirl flow, and the swirl flow causes the impeller 28 to rotate around the outer circumference of the impeller shaft 20.

When the impeller 28 rotates, the position of the reflecting member with respect to the reflection type photosensor changes, so that the output signal of the reflection type photosensor changes. This output signal is sent to a detection circuit (not shown), the rotational speed of the impeller 28 is detected from the change pattern of the signal, and the flow rate can be calculated and obtained. The various preferred embodiments of the present invention have been described above.
The present invention is not limited to the above-described embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention.

[0016]

With the flow meter according to the present invention, the rectifying means has a plurality of spiral ridges formed on the upstream end face, and the spiral ridges are parallel to the flow passage direction in the cross section in the flow passage direction. With such a configuration, even if the flow rate is small, it is possible to smoothly flow in a spiral shape with almost no resistance and generate a swirling flow. The sensitivity, accuracy, and resolution can be significantly improved. Further, if the structure of claim 2 is adopted, the outer surface area of the upstream end of the rectifying means can be increased, so that the length of the spiral ridge can be shortened and a swirling flow can be reliably generated. . further,
When the configuration of claim 4 is adopted, the rectifying means can be easily and surely attached, and lateral leakage between the tip end portion of the spiral ridge and the inner surface of the flow passage can be prevented, so that the fluctuation of the swirling flow can be prevented. Therefore, it is possible to suppress the error (instrumental error) of the flowmeter, which is very effective.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a flow meter according to the present invention.

FIG. 2 is a cross-sectional view of the impeller of the flow meter of the embodiment.

FIG. 3 is a plan view seen from the upstream side of the impeller of the flow meter of the embodiment.

FIG. 4 is a graph showing the relationship between the flow rate and the detection output for the flowmeter of the example and the conventional flowmeter.

[Explanation of symbols]

 14 inflow port 16 outflow port 18 flow path 22 magnetic detection element 28 impeller 34 blades 38 magnet 40 impeller 44 spiral convex ridge 46 edge 50 spiral concave groove

Claims (4)

[Scope of utility model registration request] 1. An impeller rotating by receiving fluid pressure of a fluid flowing in a flow path, and a rectifying means fixed to an upstream side of the impeller in the flow path for generating a swirling flow in the fluid. And a plurality of spiral ridges are formed on the upstream end surface of the flow rectifying means, and the spiral ridges are formed parallel to the flow passage direction in a cross section in the flow passage direction. A flow meter characterized in that. 2. The rectifying means has an upstream end portion formed in a conical shape, and the spiral ridge is formed on an outer surface of the conical end portion. Flowmeter. 3. The flowmeter according to claim 1, wherein the spiral ridge has an Archimedean spiral shape. 4. The rectifying means is characterized in that a tip end portion of the spiral ridge formed on a part of an upstream end surface is fitted into a spiral groove formed on the inner surface of the flow path. The flowmeter according to claim 1, 2 or 3, characterized in that.