JPS6013216A - Flow-rate detecting device - Google Patents

Abstract

PURPOSE:To obtain a flow-rate detecting device, which detects the rotation of a rotary body, without mounting a permanent magnet to the rotary body, by detecting the rotation of the magnetic rotary body, which is rotated by a turning axial flow by a magnetoresistance element, and operating and processing the signal. CONSTITUTION:When a fluid flows to an outlet port 4 from an inlet port 3 of a flow-rate detecting device, a turning axial flow is obtained by fixed blades 5. A magnetic spherical body 6 is turned at a speed proportional to the flow rate through a flow-out preventing body 7. The number of rotation is detected through a magnetoresistance element 10 and a permanent magnet 9 and processed and operated by a control circuit 11. Thus the flow rate is obtained. Since the rotation of the rotary body 6 is detected without mounting a permanent magnet to the rotary body 6, poor rotation due to the attachment of foreign materials such as iron powder in the fluid does not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a flow rate detection device that measures a flow rate by replacing the flow rate of a fluid with the rotational speed of a rotating body.

Conventional configuration and problems The conventional method for detecting rotation with a rotating body detection type flow sensor is to attach a permanent magnet to the outer periphery of the rotating body and place a Hall element or magnetic resistance element in close proximity. Alternatively, there is a method of detecting with light using a photo coupler.

In the case of optical detection, a configuration in which a photocoupler is placed in the flow path is common, but it is susceptible to dirt and dust in the flow path, has problems with reliability over time, and also makes the detection part expensive. It has its drawbacks. On the other hand, there are also problems with the above-mentioned detection method by installing a permanent magnet on the rotating body.
This will be explained with reference to the figure. The figure shows a vane-wheel type flow sensor, in which fluid flows from the direction of the arrow, rotating a vane wheel 101, whose rotation speed is proportional to the flow rate, and the rotation speed is determined by a permanent magnet 102 provided at the tip of the blade. The rotation is detected as a pulse by a magnetoresistive element 103 provided outside the flow path, and a control circuit (not shown) calculates and measures the flow rate. In this case, as mentioned above, it is necessary to attach permanent magnets to the blades, and it is necessary to devise ways to attach them so that the magnets do not come off over a long period of time.Foreign objects such as iron powder in the flow path may still adhere to the blades, causing rotational problems. However, there are some problems associated with attaching permanent magnets to the rotating body, such as being easy to use.

OBJECTS OF THE INVENTION The present invention solves the problems of the prior art, and aims to provide a flow rate detection device that detects the rotation of a rotating body without installing a permanent magnet on the rotating body.

Structure of the Invention To achieve this object, the present invention includes a magnetic rotating body that rotates (orbits) due to the flow of fluid in a flow path, a magnetic sensor that detects the rotation of the rotating body, and a magnetic field applied to the magnetic sensor. and a control circuit that processes signals from the magnetic sensor, and the rotating body rotates by passing between the magnetic sensor and the magnet. . This configuration enables highly reliable rotation detection and flow rate detection.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 to 4. 1 is a casing of a flow path 2 of the flow rate detection device, 3 is an inlet thereof, and 4 is an outlet thereof. Reference numeral 5 denotes a fixed blade that gives a swirling flow to the fluid flowing in the direction of the arrow, and has blades that are not parallel to the flow, and is fixed to the casing 1 by press fitting or the like so as not to rotate due to the flow of the fluid. Reference numeral 6 denotes a magnetic sphere (rotating body) that exists in a free state downstream of the fixed blade 5 and rotates within the flow path in a direction perpendicular to the flow due to the swirling flow of the fluid.

The magnetic material is made of magnetic stainless steel, resin balls with magnetic material inserted to reduce weight, resin balls with magnetic surface treatment, etc. Reference numeral 7 denotes an outflow prevention body for the sphere 6, which serves as a holder for the sphere to rotate six times around.A permanent magnet 9 is embedded near the upstream tip 8 in the center of the flow path of the outflow prevention body 7 (near the circumferential surface of the sphere 6), and its magnetic flux is It is provided in the direction facing the channel wall. 1
0 is a magnetoresistive element (magnetic sensor), which is located outside the flow path near the circumferential circuit of the sphere 6 and is fixed to the casing 1 with a fixture 11. 12 is a control circuit that processes signals from the magnetoresistive element 10. Note that 13 in FIGS. 3 and 4 indicates lines of magnetic force of the permanent magnet 9.

Next, the operation will be explained. When the fluid flows from the inlet 3 toward the outlet 4, it becomes an axial swirling flow at the fixed blades 5, and the swirling flow causes the sphere 6 to revolve in the flow path. Since the rotational speed of the circuit is proportional to the flow rate, the rotational speed is detected by the magnetoresistive element 10, and the flow rate is determined by arithmetic processing by the control circuit 12. Detection of magnetism in the magnetoresistive element 10 is shown in FIGS. 3 and 4.
This will be explained with reference to the figure. In FIG. 3, a magnetic sphere 6
is further away from the magnetoresistive element 10, and the magnetic force lines 13 of the permanent magnet 9 have a weak influence on the element 10. On the other hand, as shown in FIG. 4, when the magnetic sphere 6 comes between the permanent magnet 9 and the magnetoresistive element 100, the lines of magnetic force 13
will move intensively in the 6 directions of the sphere due to the influence of the magnetic sphere.

Due to this change in the lines of magnetic force 13, the influence of the lines of magnetic force 13 on the magnetoresistive element 10 in the vicinity of the sphere 61C becomes the strongest at this time. Therefore, the movement (circling) of the sphere 6 is controlled by the permanent magnet 9.
The magnetoresistive element 10 captures the strength of the lines of magnetic force 13 from the magnetic field 13, and detects the number of times (the number of rotations of the sphere 6) in a pulse manner. The rotation signal and flow rate detected by the control circuit 12 can be displayed as an instantaneous flow rate of a flow meter, or when this flow rate detection device is incorporated into a device as a flow sensor, the signal source for controlling the device or It will be used for purposes such as.

In the above embodiment, the rotating body is a sphere, which rotates in an axial flow using fixed blades, and the size of the sphere 6 is much smaller than the passage area of the flow path 2, and the blades are also fixed and the structure is narrow. There are no parts. Therefore, it can be used as a flow rate detection device with less pressure loss. It has a structure that is resistant to sewage such as water stains and scale.

Note that the present invention is not limited to the above-mentioned configuration, and the rotating body 6 may have a non-spherical rod shape or a cylindrical shape, the rotating means may have a screw plate shape, and the flow path structure may have an annular flow path in the flow direction. There are also sensor configurations in which a sphere revolves around an annular flow path using the jet force of fluid, and magnetic sensors for detecting rotational speed using Hall elements or pickup coils, etc., and are not limited to the configurations of the above embodiments. do not have.

Effects of the Invention As described above, according to the flow rate detection device of the present invention, the magnetic rotating body that rotates (orbits) due to the flow of fluid in the flow path,
The rotating body is configured to rotate by passing between a magnetic sensor and a permanent magnet, and the rotating body is not equipped with a permanent magnet, so that the following effects can be obtained.

(1) When attaching a permanent magnet to a rotating body, it is necessary to devise a highly reliable attachment method so that the permanent magnet does not come off for a long time.
In addition, there are problems associated with attaching permanent magnets to the rotating body in the flow path, such as the possibility that foreign matter such as iron powder or metal chips in the fluid may adhere to the rotating body and cause rotation failure. , the rotation of the magnetic body is detected by a permanent magnet on the fixed side and a magnetic sensor, so there is no risk of the above problem occurring.
This is a highly reliable flow rate detection device.

(2) Compared to a vane-wheel type flow sensor, the rotating body of the present invention does not need to have a shaft or a bearing, and there is no narrow moving part in the flow path, so it is free from dirt containing water scale, scale, dirt, etc. It has a structure that is resistant to fluids.

(3) When detecting a moving (orbiting) magnetic body using a combination of a permanent magnet on the fixed side and a magnetic sensor, this configuration is the most sensitive detection configuration for the magnetic sensor, and stable rotation speed detection is possible. It is possible.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional flow rate sensor, Fig. 2 is a cross-sectional view showing an embodiment of the flow rate detection device of the present invention, and Figs. 3 and 4 are enlarged views of the rotating body detection section and illustrate operating states. shows. 2...Flow path, 6...Sphere (rotating body), 1
0... Magnetoresistive element (magnetic sensor), 9...
・Permanent magnet (magnet), 12... Control circuit, 5.
...Fixed wing, 7... Outflow prevention body. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 1 Figure 4

Claims (4)

[Claims] (1) A magnetic rotating body that rotates with the flow of fluid in a flow path, a magnetic sensor that detects the rotation of this rotating body, a fixed magnet that can apply a magnetic field to this magnetic sensor, and a control circuit for processing a signal, the rotating body passing between the magnetic sensor and the magnet to rotate. (2) A fixed blade that gives axial swirl to the fluid and a rotating body outflow prevention body are provided on the downstream side thereof, and the rotating body is rotated between the blades in a plane perpendicular to the flow, and the magnetic sensor is attached to the rotating body orbiting part. 2. The flow rate detection device according to claim 1, wherein a magnet is embedded in the outflow prevention body at a position close to the magnetic sensor near the center of the flow path outside the flow path. (3) The flow rate detection device according to claim 2, wherein the magnetic sensor is a magnetoresistive element. (4) The flow rate detection device according to claim 2, wherein the magnet is a permanent magnet.