JPS6337326B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to the overall configuration of a flow rate detection device for measuring the flow rate of fluid.

Configuration of Conventional Example and its Problems Conventionally, this type of flow rate detection device is configured as shown in FIGS. 1 and 2. In FIGS. 1 and 2, reference numeral 1 denotes an annular channel having a circular cross section, and an inflow channel 2 and an outflow channel 3 are opened at the outer periphery of this channel. This inflow passage 2 is provided with a nozzle 4 . In addition, a sphere 5 is inserted into the annular flow path 1, transparent windows 6 and 7 are formed, and a light emitting element 8 is formed.
and a light receiving element 9 are provided. In such a configuration, when fluid enters the annular channel 1 from the nozzle 4 of the inflow channel 2, the flow flows from the inflow channel 2 to the outflow channel 3 while circulating in the annular channel 1, and the sphere 5 also flows along with it. It moves around inside the annular flow path 1 in the direction of the solid arrow. Since the rotational speed of the sphere is proportional to the flow rate of the fluid, the rotational speed of the sphere 5 is detected as a pulse signal by the light emitting element 8 and the light receiving element 9, and the flow rate is measured through the control circuit.

The first problem with this conventional example is that the flow resistance is large. Since the annular flow path 1 is formed, the inlet and outlet of the flow path change direction, resulting in bending loss, and the circular flow intersects with the flow from the inflow path 2 near the inflow path, resulting in inflow resistance and loss. arise. Furthermore, if the sphere is configured to have a size close to the cross-sectional area of the annular flow path 1 so as to promote the rotation of the sphere 5, a large flow resistance will occur. Further, if a nozzle 4 is provided in the inflow passage 2 so that the sphere 5 circulates smoothly, the flow passage resistance becomes even greater. Second, there are problems with the structure, such as the fact that the sensor structure tends to be large. As mentioned above, the passage resistance increases, so it is necessary to increase the passage diameter to reduce it.Also, since it has an annular passage 1 compared to a straight pipe, a corresponding space is required for the sensor. Overall, it is larger than the front and rear aisles. In addition, the directions of the inflow passage 2 and the outflow passage 3 are limited to some extent, which poses problems such as structural restrictions when incorporating the sensor into equipment, etc., and an increase in overall size. Furthermore, an example of a conventional ball having donut-shaped channels on the upstream and downstream sides is disclosed in Japanese Patent Application Laid-open No. 51758/1983. This is because the upstream and downstream donut-shaped channels have different shapes, and the ball revolves between the upstream and downstream donut-shaped channels.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a small and compact flow rate detection device that eliminates such conventional drawbacks and has low flow resistance.

Composition of the Invention In order to achieve this object, the present invention includes a swirling vane for axially swirling a fluid to be detected, a rotating body that rotates in the swirling flow, and a means for preventing outflow of the rotating body.
The outflow prevention means includes a detection means for detecting the rotation speed of the rotating body, and the outflow prevention means has a donut shape in which the cross section of the upstream flow path gradually decreases toward the downstream side, and the cross section of the downstream flow path gradually expands toward the downstream side. It is donut-shaped, and the upstream flow path and the downstream flow path having the donut-shaped cross section are configured in the same shape and symmetrically, and the rotating body is configured to revolve at the upstream flow path position of the outflow prevention means. It is.

With this configuration, the flow direction of the fluid is the axial direction, a rotating body whose area is smaller than the flow path area is rotated in the swirling flow, and an outflow prevention means is used that has a configuration that gradually contracts and gradually expands. This results in a configuration with less flow loss, resulting in lower flow resistance and a smaller and more compact flow rate detection device.

DESCRIPTION OF EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS. 3 and 4.

In FIG. 3, reference numeral 10 denotes a housing, and inside the housing 10, a swirling vane 11 for axially swirling the fluid to be detected is fixed to a casing 12. The swirling wing 11 is composed of an arcuate wing 13 and a shaft 14. A magnetic sphere 15, which is a rotating body, is located downstream of the rotating blade 11, and a sphere receiver 16, which is a means for preventing the magnetic sphere 15 from flowing out, is fixed to the casing. The upstream flow path 17 of this spherical receiver 16 is configured in a tapered donut shape with a cross section that gradually decreases toward the downstream side, and the downstream flow path 18 is configured in a tapered donut shape with a cross section that gradually expands toward the downstream side. has been done. Also, the upstream flow path 1
7 and the downstream flow path 18 have the same shape and are symmetrically constructed. A permanent magnet 19 is located outside the housing 10.
A rotation detector 21, which is a means for detecting the magnetic sphere 15 and includes a magnetoresistive element 20, is provided to constitute a flow rate detection device. Note that the magnetic sphere 15
The configurations include hollow steel balls, solid steel balls, and resin balls with iron-nickel (FeNi) plating on the surface. 22 is a retaining ring of the casing 12. 2
3 and 24 are an inlet and an outlet, and 25 is an arrow indicating the direction of rotation of the magnetic sphere 15.

FIG. 4 shows the spherical receiver 16, and the upstream flow path 17 and the downstream flow path 18, which are comprised of an inner tapered surface 26 and an outer tapered surface 27, are configured in a donut shape. Note that the inner tapered surface 26 becomes a circumferential surface when the magnetic sphere 15 rotates circumferentially.

Next, the operation of the above configuration will be explained with reference to FIGS. 3 and 4. The fluid to be detected flowing in from the inlet 23 flows downstream along the arcuate blades 13 and is swirled in an axial flow. The magnetic sphere 15 obtains a kinetic force from this swirling flow and rotates in a direction perpendicular to the direction of the flow. At this time, the magnetic sphere 15 contacts two points, the inner tapered surface 26 of the sphere receiver 16 and the casing 12, and rotates. After the fluid to be detected becomes a swirling flow, it flows out through the downstream flow path 18 to the outlet 24 . Since the number of rotations of the magnetic sphere 15 is proportional to the flow rate, the flow rate can be measured by measuring the number of rotations of the magnetic sphere 15. This method involves applying a magnetic field of constant strength to the magnetoresistive element 20 using a permanent magnet 19, and extracting the change in the resistance value of the magnetoresistive element 20 as a voltage pulse change when the magnetic sphere 15 passes through this magnetic field. The processing is performed via a control circuit (not shown). In this embodiment, the upstream channel 17 of the ball receiver 16 has a tapered cross section, so even if the diameter of the magnetic ball 15 becomes smaller due to wear during long-term use, the inner tapered surface 26 Since the magnetic sphere 15 contacts the magnetic sphere 15 at the same angle, there is very little change in abrasion resistance during circling, and stable circling accuracy can be obtained. In addition, the upstream channel 17 has a doughnut-shaped cross section.
By symmetrically configuring the downstream flow path 18 in the same shape, the directionality of the ball receiver 16 is eliminated, and especially during assembly, it is possible to eliminate the difference in the direction of assembly.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 5 shows a spherical receiver 28, and the center portion 29 of the spherical receiver 28 is configured in a bell-shaped streamlined shape. This shape has the effect of reducing the flow resistance when the fluid to be detected passes through the spherical receiver 28 compared to the tapered flow path cross section.

Effects of the Invention As is clear from the above description, the flow rate detection device of the present invention includes a swirler that axially swirls the fluid to be detected, and a swirler that is located inside the swirler and rotates in a plane perpendicular to the flow direction. It consists of a rotating body, an outflow prevention means for keeping the rotating body within the range of the swirling flow, and a detection means for detecting the number of rotations of the rotary body, and the outflow prevention means is configured so that the cross section of the upstream flow path is on the downstream side. The cross section of the downstream flow path is a donut shape that gradually decreases toward the downstream side, and the upstream flow path and the downstream flow path having these donut shaped cross sections are configured symmetrically with the same shape, By arranging the rotating body to rotate at a position in the flow path upstream of the outflow prevention means, the following effects can be obtained.

(1) Initial characteristics can be obtained by replacing the upstream and downstream sides of the outflow prevention means. That is, since the outflow prevention means, the upstream flow path, and the downstream flow path have the same shape and are constructed symmetrically, if the outflow prevention means wears out due to long-term use and its characteristics change, the outflow prevention means It is only necessary to replace the upstream and downstream sides of the device, and repairs can be made without replacing with new parts, making it a practical and effective means for extending the life of the device.

(2) Low flow resistance. Since the fluid to be detected flowing in from the inlet undergoes axial swirl as it flows downstream along the arcuate blade, it is possible to reduce loss during conversion to axial swirl. Furthermore, the rotating body has a much smaller diameter than the flow path area, so loss is small. Since the upstream flow path and the downstream flow path of the outflow prevention means are each configured in a donut shape that gradually contracts and expands, it is possible to reduce losses during contraction and expansion flow. Furthermore, there are no bends in the fluid itself, and these factors realize low flow resistance.

(3) The structure of the flow rate detection device becomes smaller and more compact. Unlike those in which the flow path itself forms an annular flow path, it has the advantage of having an axial flow swirl in a straight pipe section, and the flow path is the simplest and can be constructed with a short flow path length.

(4) Improved sensitivity of flow rate detection. Since the upstream flow path of the outflow prevention means is gradually reduced and the flow path area is smaller than that immediately after the swirler, the flow velocity of the swirling flow of the detected fluid at the position of the upstream flow path becomes faster than immediately after the swirler. Therefore, even at a small flow rate, the swirling flow velocity in the upstream flow path is high, and the rotating body placed in this upstream flow path can rotate easily, resulting in improved sensitivity.

[Brief explanation of the drawing]

Figures 1 and 2 are a horizontal cross-sectional view and a vertical cross-sectional view of a flow path of a conventional flow rate detection device, Figure 3 is a cross-sectional view of a flow rate detector showing an embodiment of the present invention, and Figure 4 is a flow prevention device. Fig. 5 is an external perspective view of the outflow prevention means in another embodiment of the present invention. 11...Swirling blade, 15...Rotating body (magnetic sphere),
16... Outflow prevention means (spherical receiver), 17... Upstream channel, 18... Downstream channel, 21... Detecting means (rotation detector).

Claims (1)

[Claims] 1. A swirling vane that axially swirls the fluid to be detected flowing in a flow path to generate a swirling flow, and a rotating body that is located in this swirling flow and rotates in a plane perpendicular to the flow direction. , an outflow prevention means for keeping the rotating body within the range of the swirling flow, and a detection means for detecting the number of rotations of the rotary body, and the outflow prevention means is configured so that the cross section of the upstream flow path gradually moves downstream. The cross section of the downstream channel is a donut shape that shrinks, and the cross section of the downstream channel gradually expands toward the downstream side, and the upstream channel and the downstream channel having the donut shaped cross section are configured in the same shape and symmetrically. A flow rate detection device in which a rotating body rotates at a flow path position upstream of the outflow prevention means. 2. Flow rate detection according to claim 1, wherein the upstream flow path has a tapered donut shape in which the cross section narrows toward the downstream side, and the downstream flow path has a tapered donut shape in which the cross section expands toward the downstream side. Device.