JP2638204B2 - Flow detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid detector used for detecting the flow rate of water or hot water in a hot water supply device or a hot water heating device, or detecting the fuel flow rate of a liquid fuel supply device. Things.

2. Description of the Related Art Conventionally, as this kind of flow rate detecting device, there is one as shown in FIGS. In FIGS. 10 and 11, reference numeral 1 denotes a housing. Inside the housing 1, a fixed blade 3 having a plurality of blades 2 for turning a fluid into a swirling flow is fixed to a channel inner wall 4. A sphere 5 having a magnetic material inside is provided as a rotating body orbiting in the flow path downstream of the fixed wing 3, and the sphere 5 is prevented from flowing downstream to the downstream of the sphere 5. A sphere receiver 7 having a circumferential contact surface 6 of the sphere 5 is provided. Outside the housing 1, a detector 8 for detecting the rotation of the sphere 5 is provided. The detector 8 includes a magnetoresistive element 9, a permanent magnet 10 for applying a magnetic field to the magnetoresistive element 9, and an electronic circuit 11 for processing an output signal of the magnetoresistive element 9. When the fluid flows from the left arrow side in the drawing in the conventional example configured as described above, the fluid becomes a swirling flow by the fixed wings 3, and the sphere 5 located in the swirling flow contacts the orbiting contact surface 6 of the sphere receiver 7. The orbiting motion continues in the direction perpendicular to the direction of the contact flow. At this time, the sphere 5 moves at a rotational speed proportional to the flow rate. Because the flow passage area in the fixed blade 3 is constant, the flow velocity when passing through the fixed blade 3 is proportional to the flow rate. Therefore, the sphere 5 placed on the downstream side of the fixed wing 3 also rotates at a rotation speed proportional to the flow rate. Means for detecting the rotation of the sphere 5 is performed by magnetic detection. That is, a permanent magnet 10 is provided in the vicinity of the magnetoresistive element 9 for applying a magnetic field of a constant strength to the magnetoresistive element 9. Now, when the sphere 5 having a magnetic material therein passes below the magnetoresistive element 9, the direction of the magnetic field acting on the magnetoresistive element 10 from the permanent magnet 10 changes to the sphere 5 side. The resistance value of the magnetoresistive element 9 changes. The change in the resistance value is regarded as a change in the voltage, converted into a pulse signal and output. Therefore, each time the sphere 5 makes one rotation, a signal of one pulse is output. As shown in FIG. 12, the relationship between the flow rate and the rotation speed of the sphere is represented by a linear straight line 12 in the spherical rotation speed characteristics in such a configuration. The relationship between the flow rate and the pressure loss is represented by a quadratic curve 13 as shown in FIG.

Problems to be Solved by the Invention However, such a flow rate detection device has a problem that the pressure loss in a large flow rate region is large. That is, since the flow passage area in the portion of the fixed blade 3 is constant, the pressure loss is represented by a quadratic curve with respect to the flow rate as described above. In the case of a large pressure loss, for example, when incorporated in a water heater, the pressure loss at the time of a large flow rate is large. Therefore, when the water supply pressure is low, there is a problem that a sufficient amount of hot water cannot be obtained.

Accordingly, a first object of the present invention is to reduce the pressure loss at a large flow rate without changing the size of the flow rate detector.

A second object is to reduce pressure loss at the time of a large flow rate and to enable detection of a small flow rate.

Means for Solving the Problems In order to achieve the first object, the present invention provides a swirl means having a wing part for axially swirling a detected fluid flowing in a flow path, and a swirl flow generated by the swirl means. And a sphere that orbits in a plane perpendicular to the direction of flow, the sphere, a sphere receiver that is located downstream of the sphere and has a circulating abutment surface of the sphere, and a rotation that measures the number of revolutions of the sphere Detecting means, wherein the swirling means has a structure in which a gap is provided in a part of a fixed portion between the wing portion and the inner wall of the flow passage.

Further, in order to achieve the second object, the present invention is configured such that a gap provided at a part of a fixed portion between the wing portion and the inner wall of the flow passage is closed on the upstream side of the wing portion.

The flow rate detection device of the present invention flows a part of the fluid to be detected flowing through the flow path and swirling at the wing portion from the gap portion of the wing portion which is not fixed to the inner wall of the flow path to the downstream side, with the above configuration. In this case, the blades are deformed by the flow to reduce the pressure loss at a large flow rate.

In the present invention, a small flow rate can be detected by closing the gap on the upstream side of the wing, thereby reducing the amount of leakage from the gap.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. 1 and 2, reference numeral 14 denotes a housing. Inside the housing 14, fixed wings 16 having a plurality of wings 15 for turning the fluid to be detected into a swirling flow are fixed to an inner wall 17 of the flow passage by a fixing portion 17A. Fixed. Wing part 15 of the fixed wing 16
The flow path inner wall 17 has a configuration in which a gap 18 is provided in a part. The fixed wing 16 is made of resin, and the downstream end 19 of the wing 15 is easily bent like a wavy line. Downstream of the fixed wings 16, a sphere 20 having a magnetic material therein is provided as a rotating body orbiting in the flow path, and at the downstream of the sphere 20, the sphere 20 is prevented from flowing out downstream. A sphere receiver 22 having a circumferential contact surface 21 of the sphere 20 is provided. A detector 23 for detecting rotation of the sphere 20 is provided outside the housing 14. The detector 23 includes a magnetoresistive element 24, a permanent magnet 25 for applying a magnetic field to the magnetoresistive element 24, and the magnetoresistive element.
An electronic circuit 26 for processing the 24 output signals and outputting pulses is built in. In the present invention thus configured, when the fluid to be detected flows in from the left arrow side in the drawing, the fluid to be detected becomes a swirling flow by the fixed wings 16, and the sphere 20 located in the swirling flow corresponds to the orbit of the sphere receiver 22. The abutment surface 21 abuts on the contact surface 21 and continues the orbiting motion in the direction perpendicular to the flow direction. When a small flow rate flows, a part of the fluid to be detected flows through the gap 18, so that the starting flow rate at which the sphere 20 starts to rotate is larger than the conventional one as shown in FIG. 7A. As the flow rate further increases, the rotational speed of the sphere 20 increases proportionately. Thereafter, when the flow rate increases, the downstream end portion 19 of the wing portion 15 is deformed as shown by a dashed line in FIG. Accordingly, as shown in FIG. 3, the rotational speed of the sphere 20 changes substantially linearly up to a certain flow rate, becomes a large flow rate, and when the downstream end portion 19 of the wing portion 15 is deformed, the rotational speed of the sphere 20 becomes the linear speed. The deviation from the line is reduced, and the rate of change of the rotation speed is reduced. As shown in FIG. 4, the pressure loss is different from the characteristic in the small flow rate region and the characteristic in the large flow rate region, and has a characteristic having an inflection point. As described above, in the present embodiment, at the time of a large flow rate, the downstream end portion 19 of the wing portion 15 is deformed, and the flow area of the wing portion 15 is increased. Can also be reduced, resulting in a reduced pressure loss. Next, another embodiment of the present invention will be described with reference to FIGS. Reference numeral 27 denotes a wing portion of a fixed wing 28, and the wing portion 27 and the flow path inner wall 29 are fixed to each other with a gap portion 30 by a fixing portion 17A. Numeral 31 is a groove provided on the downstream side surface of the wing portion 28.By providing the groove 31, the downstream end portion 32 of the wing portion 28 is easily deformed at a large flow rate, and the effect of reducing the pressure loss can be increased. You can do it.

Next, another embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIGS. Reference numeral 33 denotes a wing portion of the fixed wing 34, and the wing portion 33 and the flow path inner wall 35 are fixed by a fixing portion 17A with a gap portion 36. Further, a bush 37 is inserted upstream of the wing 33 so as to close the gap 36. The bush 37 has a cylindrical shape, and the inner diameter of the bush 37 is smaller than the inner wall 35 of the flow passage so as to close the gap 36. The contact end 38 of the bush 37 with the wing 33 is formed in a shape closely contacting the wing 33. In such a configuration, when the fluid to be detected flows from the left arrow side in the figure, the amount of the fluid to be detected leaks from the gap 36 is extremely small, and as shown by the point B in FIG. As a result of rotation from a small flow rate, a small flow rate can be detected. Naturally, at a large flow rate, the pressure loss can be reduced by deforming the wing portion 33.

Effect of the Invention As described above, the flow rate detection device of the present invention is a swirling unit having a wing portion that axially swirls the fluid to be detected flowing in the flow path,
A sphere positioned in the swirling flow of the swirling means and orbiting in a plane perpendicular to the direction of flow, a sphere receiver positioned downstream of the sphere and having a circulating abutment surface of the sphere, and a rotational speed of the sphere The rotation unit is provided with a gap in a part of the fixed portion of the wing portion and the inner wall of the flow path, the wing portion has a deformable configuration,
The blade portion is deformed by the action of the drag of the flow at a large flow rate, and the flow path area at the blade portion is larger than the area at a small flow rate, so that the pressure loss can be reduced. In addition, by increasing the flow path area, the flow velocity is reduced and the number of revolutions of the sphere is reduced, which has an advantageous effect on the wear durability of the sphere. Furthermore, by adopting this configuration, the pressure loss can be reduced without increasing the diameter of the inner wall of the flow path, so that the flow rate detection device can be configured to be small and compact.

Further, according to the present invention, by closing a gap provided at a part of the fixed portion between the wing and the inner wall of the flow passage on the upstream side of the wing, the amount of leakage from the gap is extremely reduced when a small flow rate flows. Therefore, a small flow rate can be detected.

[Brief description of the drawings]

FIG. 1 is an external view of a fixed wing and a sphere in a cross section of a housing of a flow detecting device showing an embodiment of the present invention, FIG. 2 is a left sectional view of FIG. 1, FIG. 3 and FIG. Characteristic diagram,
FIG. 5 is an external view of a fixed wing and a sphere in a cross section of a housing showing another embodiment of the present invention, FIG. 6 is a left sectional view of FIG. 5, and FIG. 7 shows a third embodiment of the present invention. FIG. 8 is a left side sectional view of FIG. 7, FIG. 9 is a characteristic diagram of the third embodiment of the present invention, and FIG. FIG. 11 is an external view of a fixed wing and a sphere in a cross section of a housing of the detection device, FIG. 11 is a left side cross-sectional view of FIG. 10, and FIGS. 12 and 13 are characteristic diagrams of a conventional example. 15 wing part, 16 circling means (fixed wing), 17 channel inner wall, 18 gap (gap part), 20 sphere, 21 circulating abutment surface, 22 sphere receiver , 23 ... rotation detecting means (detector).

Claims (1)

(57) [Claims] 1. A swirling means having wings for axially swirling a fluid to be detected flowing in a flow path, a sphere positioned in a swirling flow of the swirling means and orbiting in a plane perpendicular to the flow direction, A sphere receiver which is located downstream of the sphere and has a circling contact surface of the sphere, and rotation detection means for measuring the number of revolutions of the sphere, wherein the turning means includes the wing portion and the inner wall of the flow path. A flow rate detection device in which a gap is provided in a part of the downstream side of the fixed portion where the fixed portion is fixed.