JPS6013218A - Flow-rate detecting device - Google Patents

Abstract

PURPOSE:To obtain a flow-rate detecting device, which detects the rotation without mounting a permanent magnet to a rotary body, by detecting the number of rotation of a magnetic rotary body, which is rotated by a turning axial flow, by a magnetoresistance element, and performing the operation and processing. 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 rotary body 6 is turned at a speed proportional to the flow rate through a flow-out preventing body 7. The rotary body 6 comprises a nonmetal including a magnetic material 12 in a powder or granular state. The number of rotation of the rotary body is detected through a magnetoresistance element 8 and a permanent magnet 9 and operated and processed by a control circuit 11. Thus the flow rate is obtained. Since a permanent magnet is not mounted to the rotary body 6, poor rotation due to the attachement of foreign material such as iron poder in the fluid does not occur. Thus the highly reliable flow rate can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a flow rate detection device that expands the 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 in which a detection section made of a ferromagnetic metal material is detected using a magnetoresistive element equipped with a bias magnet. An example thereof will be explained with reference to FIG. 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 the magnets so that they do not come off over a long period of time.Furthermore, foreign matter such as iron powder in the fluid can easily adhere to the blades and cause rotational problems. Such,
There were problems caused by attaching permanent magnets to the rotating body.

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 attaching a permanent magnet to the rotating body.

Structure of the Invention In order to achieve this object, the present invention provides a rotating body having magnetism that rotates with the flow of fluid in a flow path, a magnetic sensor that detects the rotation of the rotating body, and a signal processing from the magnetic sensor. The rotating body constitutes a flow rate detection device made of a non-metallic material containing a magnetic material in the form of powder, grains, or fibers. 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 5.

In FIG. 2, 1 is the casing of the flow path 2 of the flow rate detection device, 3 is its inlet, and 4 is its outlet. 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. 6 is a spherical rotating body that exists in a free state downstream of the fixed blade 5 and rotates in the flow path in a direction perpendicular to the flow due to the swirling flow of the fluid; 7 is an outflow prevention body of the rotating body 6; It will be accepted on a regular basis. A magnetoresistive element (magnetic sensor) 8 is located outside the flow path near the circumferential circuit of the rotating body 6, and is fixed to the casing 1 with a fixture 10 together with a permanent magnet 9 that applies a magnetic field to the magnetoresistive element 8. 11 is a control circuit that processes signals from the magnetoresistive element 8; 3 to 5 show the structure of the rotating body 6. FIG. Each rotating body is formed of a resin molded product containing a magnetic material such as iron or ferrite inside. Figure 3 shows the rotating body 6.
contains powder or granular magnetic material 12. Fourth
The figure shows another embodiment of the rotary body 6, and the rotary body 6 contains a fibrous magnetic material 13. FIG. 5 also shows another embodiment of a spherical body, which contains a magnetic material 14 and is formed by a hollow rotating body 6.

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 rotating body 6 rotates in the flow path due to the swirling flow. Since the rotational speed of the circuit is proportional to the flow rate, the rotational speed is detected by the magnetoresistive element 8, and the flow rate is determined by arithmetic processing by the control circuit 11. The direction of the magnetic flux acting on the magnetoresistive element 8 from the permanent magnet 9 changes when the ferromagnetic sphere 6 containing iron powder approaches, and the magnetoresistive element 8 pulses this change. It will be detected accurately. The rotation signal and flow rate detected by the control circuit 11 in this way can be displayed as an instantaneous flow rate of a flow meter, or when this flow rate detection device is incorporated into equipment as a flow sensor, it can be used to start/stop or control the equipment. It will be used for purposes such as serving as a signal source.

In the above embodiment, the rotating body is a sphere, and has a configuration in which it rotates in an axial flow using fixed blades, and the size of the rotating body 6 is much smaller than the passage area of the flow path 20, and the blades are also fixed and structurally narrow. There are no parts. Therefore, as a flow rate detection device, there is little pressure loss, and the structure is resistant to sewage such as water scale and scale.

It should be noted that the present invention is not limited to the above-mentioned configuration, but also includes configurations in which the rotating body 6 is not a sphere, such as a rod shape or a cylindrical shape, a configuration in which the rotating body is an impeller and does not have fixed blades, and a configuration in which the flow path configuration is an annular flow in the flow direction. It is also possible to use a pickup coil type magnetic sensor for detecting the number of revolutions, or a sensor configuration in which a sphere circulates around an annular flow path using the jet force of fluid, but both are limited to the configuration of the above embodiment. It's not a thing.

Effects of the Invention As described above, according to the flow rate detection device of the present invention, the rotating body is a magnetic body containing powder, granular, or fibrous magnetic material and is not equipped with a permanent magnet, so that the following effects can be obtained. It will be done.

(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.
There are problems associated with attaching permanent magnets to the rotating body in the flow path, such as foreign matter such as iron powder and metal cutting powder still in the fluid, which may adhere to the rotating body and cause rotational failure. Since the present invention has a configuration in which the rotation of the magnetic body is detected by a magnetic sensor, there is no possibility of the above-mentioned problem occurring, and the flow rate detection device is highly reliable.

(2) Since the rotating body is made of a non-metallic material and is lightweight, it is easy to operate even with a small flow of fluid, and the sensitivity flow rate as a flow rate detection device is low.

(3) When the rotating body moves in contact with the flow path side wall or the outflow prevention body, it is softer and lighter than when the rotating body is made of metal, and its kinetic energy is also small, causing wear and noise due to contact rotation. occurrence is small.

(4) Since the rotating body is made of a non-metallic material such as resin molding containing a magnetic material, it is easy and inexpensive to manufacture.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional flow rate sensor, FIG. 2 is a sectional view showing an embodiment of the flow rate detection device of the present invention, FIG. 3 is a sectional view of a rotating body, and FIGS. 4 and 5. FIG. 3 is a sectional view showing another example of the rotating body. 2...Flow path, 6. Rotating body, 8... Magnetoresistive element (magnetic sensor), 11... Control circuit, 12
．． 13.14... Magnetic material, 5... Fixed wing. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3

Claims (3)

[Claims] (1) The rotating body includes a magnetic rotating body that rotates with the flow of fluid in a flow path, a magnetic sensor that detects the rotation of the rotating body, and a control circuit that processes signals from the magnetic sensor. is a flow rate detection device made of a non-metallic material containing powder, granular, or fibrous magnetic material. (2) Claim 1 in which the rotating body is a sphere, which is a fixed blade that gives axial swirl to the fluid and rotates in a plane perpendicular to the flow.
Flow rate detection device as described in section. (3) The flow rate detection device according to claim 2, wherein the rotating body is a hollow resin-molded sphere.