JPH0310118A - Flow-rate detecting apparatus - Google Patents

Abstract

PURPOSE:To make it possible to detect a low flow rate by rotating a magnetic spherical body at the low flow rate even under the state wherein the magnetic spherical body is attracted to the side of a permanent magnet. CONSTITUTION:When a detecting apparatus is filled with a fluid, a magnetic spherical body 27 whose specific gravity is close to 1 is attracted to the side of a permanent magnet 35 with the magnetic force of the permanent magnet 35. When the fluid to be detected flows in the direction of an arrow under this state, the fluid to be detected is jetted through jetting ports 30 - 32 of a fixed blade 25, and a swirling stream is formed. Thus, the spherical body 27 is turned. At this time, an angle alpha between a hub 24 and a blade 23 is made larger than an angles alpha between other blades 21 and 22 and the hub 24. Therefore, the areas of the jetting ports 31 and 32 are made smaller than the area of the jetting port 30. Thus, the flow speed at the jetting port 31 through which the swirling stream that collides the stationary spherical body 27 at a position facing the permanent magnet 27 becomes faster than the flow speed of the stream jetted through the other jetting port 30. Since the collision energy to the spherical body 27 becomes large, the spherical body 27 starts turning at the low flow rate. Therefore, even if the magnetic spherical body is attracted to the permanent magnet, the low flow rate can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fluid detection device used for the purpose of detecting the flow rate of water or hot water in a water heater or hot water heating device, or for detecting the fuel flow rate in a liquid fuel supply device. It is something.

2. Description of the Related Art Conventionally, this type of flow rate detection device is shown in FIGS. 3 and 4. In FIGS. 3 and 4, 1 is a housing. Inside this housing 1 is a fixed wing 5 which is composed of a plurality of wings 2, 3, and 4 for making the fluid into a swirling flow.
is provided in close contact with the inner wall 6 of the flow path. Said fixed wing 5
A magnetic sphere 7 that rotates rfJ in the flow path is provided downstream of the flow path. This magnetic sphere 7 has a magnetic metal hollow sphere inside, the outside is molded with resin, and its specific gravity in water etc. is approximately 1.
．． This is a configuration close to 0. A sphere receiver 9 is provided downstream of the magnetic sphere 7, which prevents the magnetic sphere 7 from flowing out to the downstream side and has a rotating contact surface 8 for the magnetic sphere 7. Further, the magnetic sphere 7 is provided on the outside of the housing 1.
A detector 10 is provided to detect the rotation of. This detector 10 is provided with a magnetoresistive element 11, a permanent magnet 12 that applies a magnetic field to the magnetoresistive element 11, and an electronic circuit 13 that processes an output signal of the magnetoresistive element 11. 14
．． 15.16 is a streamline indicating the flow direction of the swirling flow, and 1
Reference numerals 7, 18, and 19 are jet ports that eject swirling flows, respectively.

In the conventional example configured as described above, when the flow rate detection device is filled with a fluid to be detected such as water, the magnetic sphere 7 whose specific gravity is close to 1 is moved toward the permanent magnet 12 side by the magnetic force of the permanent magnet 12 as shown in FIG. It is in a state of being absorbed. When the fluid to be detected flows in from the upper arrow side in the figure in such a state, the fluid to be detected flows into the jet port 17 formed by the blades 2.3.4 of the fixed blade 5.
．． It flows out from 18.19 as a swirling flow. The magnetic sphere 7 located in this swirling flow is the orbiting contact surface 8 of the sphere receiver 9.
and continues its circular motion in the direction perpendicular to the flow direction. At this time, the magnetic sphere 7 moves around at a rotational speed proportional to the flow rate. The rotation of the magnetic sphere 7 is detected by magnetic detection.

A permanent magnet 12 is provided near the magnetoresistive element 11 to apply a magnetic field of a constant strength to the magnetoresistive element 11.

Now, when the magnetic sphere 7 passes below the magnetoresistive element 11, the permanent magnet 12
The direction of the magnetic field acting on the magnetoresistive element 11 changes, and the resistance value of the magnetoresistive element 11 changes. This change in resistance value is interpreted as a change in voltage, converted into a pulse signal, and output. Therefore, one pulse signal is output every time the magnetic sphere 7 rotates once.

Problems to be Solved by the Invention However, this conventional flow rate detection device has a drawback in that the starting flow rate is large, that is, the flow rate at which the magnetic sphere 7 starts rotating is large. The reason for this is that, as shown in Fig. 4, when the fluid to be detected flows while the magnetic sphere 7 is attracted to the permanent magnet side by the magnetic force of the permanent magnet 12, the fluid flows out from the spout consisting of the blades 2 and 4. The flow collides with the magnetic sphere 7, and the magnetic sphere 7 starts rotating. However, since the magnetic sphere 7 attracting force of the permanent magnet 12 is large, a large flow is caused, and the energy of the swirling flow colliding with the magnetic sphere 7 is reduced. The magnetic sphere 7 would not rotate unless it exceeded the attractive force. Therefore, the minimum detected flow rate of the flow rate detector has become large.

Therefore, the present invention makes it possible to rotate the magnetic sphere at a low flow rate even when the magnetic sphere is attracted to the permanent magnet side,
The purpose is to reduce the minimum detected flow rate.

Means for Solving the Problems In order to solve the problems described above, the present invention provides a swirling means having a plurality of ejection ports configured with a plurality of blades for axially swirling the fluid to be detected flowing in a flow path, and the swirling means. a magnetic sphere located in the swirling flow and orbiting perpendicularly to the flow direction; a sphere receiver located downstream of the magnetic sphere and having a circular contact surface for the magnetic sphere; and a sphere receiver provided outside the flow path. rotation detecting means consisting of a magnetic detection element provided in the magnetic field of the permanent magnet, and detecting the rotation of the magnetic sphere stationary at a position facing the permanent magnet among the swirling flows ejected from the plurality of jet ports. It is constructed so that the velocity of the colliding swirling flows is increased.

Effect The present invention has the above-mentioned configuration, so that the energy of collision with the stationary magnetic sphere becomes large, so that even when the n-type sphere is attracted to the permanent magnet side, the flow rate at which the magnetic sphere starts rotating can be reduced. This enables low flow rate detection.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings. In FIGS. 1 and 2, 20 is a housing.

Inside the housing 20, fixed blades 25 made up of a plurality of blades 21, 22, 23 and a hub 24 for creating a swirling flow of fluid are provided in close contact with the inner wall 26 of the flow path. A magnetic sphere 27 orbiting in the flow path is downstream of the fixed blade 25.
is provided. The magnetic sphere 27 has a hollow magnetic metal sphere inside and a resin molded outside, and has a specific gravity close to 1 in water. A sphere receiver 29 is provided downstream of the magnetic sphere 27 to prevent the magnetic sphere 27 from flowing out to the downstream side and has a rotating contact surface 28 for the magnetic sphere 27 . 30.
Reference numeral 31.32 is a jet nozzle composed of a plurality of blades 21.22.23. Further, the angle α between the hub 24 and the blade 21 is a constant angle (for example, 50 degrees), and the angle α between the hub 24 and the blade 21 is
The angle 2 is also configured to be the same as the angle between the hub 24 and the blade 21. However, the angle between the hub 24 and the blades 23 is larger (for example, 70 degrees) than the above-mentioned angle. Therefore, the areas of the other jet ports 31 and 32 are configured to be smaller than the area of the jet port 30. A detector 33 for detecting the rotation of the magnetic sphere 27 is provided outside the housing 20. This detector 33 includes a magnetoresistive element 34 and a permanent fj! which applies a magnetic field to this magnetoresistive element 34. stone 35
and an electronic circuit 36 for processing the signals of the magnetoresistive element 34.
is provided. 37, 38, and 39 are streamlines indicating the flow direction of the swirling flow. In the present invention configured in this manner, when the flow rate detection device is filled with a fluid such as water, the magnetic sphere 27 whose specific gravity is close to 1 is attracted to the permanent magnet 35 side by the magnetic force of the permanent magnet 35. When the fluid to be detected flows in from the upper arrow side in the figure in such a state, the fluid to be detected is ejected from the jet ports 30, 31, and 32 of the fixed blade 25, forming a swirling flow.

This swirling flow is attracted by the permanent magnet 35 and collides with the stationary magnetic sphere 27, causing the magnetic sphere 27 to rotate. In this embodiment, since the angle α between the hub 24 and the blade 23 is larger than the angle α between the other blades 21.22 and the hub 24, the area of the jet nozzle 31.32 is
It is configured smaller than 0. Therefore, the flow velocity of the jet nozzle 31 that spouts out a swirling flow that collides with the magnetic sphere 27 stationary at a position facing the permanent magnet 35 is faster than the flow velocity of the jet from the other jet nozzles 30, and the flow speed that collides with the magnetic sphere 27 increases. Because the energy increases, the magnetic sphere 27
starts rotating. The rotating magnetic sphere 27 is detected by magnetic detection. That is, when the orbiting magnetic sphere 27 passes below the magnetic resistance element 34, the direction of the magnetic field acting from the permanent magnet 35 to the magnetic resistance element 34 changes, and the magnetic resistance element 34 resistance value changes. This change in resistance value is interpreted as a change in voltage, converted into a pulse signal, and output. Therefore, magnetic sphere 2
A signal of 1 pulse is output every time 7 rotates once.

In this embodiment, f'I of one wing among a plurality of wings is
Since the configuration is such that only the angle of inclination is changed, the starting flow rate of the magnetic sphere 27 can be reduced at low pressure. Furthermore, since it has a simple configuration, it has the advantage that it can be manufactured at low cost.

Effects of the Invention As described above, the flow rate detection device of the present invention includes a swirling means having a plurality of jet ports each formed of a plurality of blades for axially swirling the detected fluid flowing in a flow path, and a swirling flow generated by the swirling means. a magnetic sphere located in the flow path and orbiting in a plane perpendicular to the flow direction; a sphere receiver located downstream of the magnetic sphere and having a rotating contact surface for the magnetic sphere; and a sphere receiver provided outside the flow path. rotation detection means consisting of a magnetic detection element provided in the magnetic field of a permanent magnet, and among the swirling flows ejected from the plurality of jet ports, collision occurs with the magnetic sphere stationary at a position facing the permanent magnet. By increasing the flow velocity of the swirling flow, even when a low flow rate flows, the collision energy that collides with the magnetic sphere increases, so even if the magnetic sphere is attracted to the permanent magnet side, the magnetic sphere easily orbits.

Therefore, it is possible to detect a low flow rate, and the flow rate detection device can measure a wide range of flow rates.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a 2iHt detection device showing an embodiment of the present invention, FIG. 2 is a cross-sectional view of FIG. 1, FIG. 3 is a sectional view of a conventional flow rate detection device, and FIG. FIG. 3 is a cross-sectional view of FIG. 21, 22. ．． 23...Tsubasa, 25...
Rotating means (fixed wing), 27...Magnetic sphere, 28
... Circumferential contact surface, 29 ... Ball receiver,
30.31.32... spout, 34...
・Magnetic detection element, 35...Permanent magnet.

Claims (3)

[Claims] (1) A swirling means having a plurality of jet ports made of a plurality of blades that axially swirls the fluid to be detected flowing in a flow path, and a swirling means located in the swirling flow caused by the swirling means and perpendicular to the direction of the flow. a magnetic sphere orbiting in a plane, a sphere receiver located downstream of the magnetic sphere and having a rotating contact surface for the magnetic sphere, and a magnetic detection element provided outside the flow path and in the magnetic field of the permanent magnet. A flow rate detection device that increases the flow velocity of the swirling flow that collides with the magnetic sphere stationary at a position facing the permanent magnet among the swirling flows ejected from the plurality of jet ports. . (2) Claim 1 in which the area of the jet of the swirling flow colliding with the magnetic sphere is smaller than the area of other jets.
Flow rate detection device as described in section. (3) The flow rate detection device according to claim 1, wherein the inclination angle of at least one of the plurality of blades is changed.