JPH0140294B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial Application Field The present invention relates to a flow rate sensor suitable for use in water heaters, etc., and more specifically, the present invention relates to a flow rate sensor suitable for use in water heaters, etc. The present invention relates to a flow rate sensor in which a brake is applied to the rotation of a detection impeller to rapidly stop the impeller.

(b) Conventional technology Flow rate sensors conventionally used in water heaters are
As shown in Figure 1, the fluid entering from the inlet i passes through the nozzle n, collides with the blades of the impeller v from the tangential direction at almost right angles, and is then guided to the outlet d, where the impeller v is proportional to the flow velocity. It was a single box type with a tangential flow impeller that rotated at a certain speed. In this type, in order to reduce the minimum operating flow rate, bearing b is connected to spindle s.
It is supported at the tip, and in order to perform highly accurate measurements even at low flow rates, it was necessary to reduce the friction of the bearing b.

However, if the friction of bearing b is reduced, the second
In the response characteristic shown by curve b in the figure, the falling response time is long, and even if the fluid flow stops, the rotation of the impeller v does not stop immediately.
Furthermore, there is a drawback that the impeller v rotates even when the fluid flows backwards.

(C) Purpose of the Invention The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to provide a flow rate sensor that operates even at minute flow rates, has a quick response, has a short falling response time, and does not cause backflow. It is about providing.

(D) Structure of the Invention The present invention provides a housing having an impeller chamber, an inlet and an outlet communicating with the impeller chamber, an impeller rotatably provided in the impeller chamber, and a housing that rotates together with the impeller. In the flow rate sensor, the flow rate sensor includes a rotor magnet provided so as to be connected to the rotor magnet, and a magnetic sensor provided in the housing adjacent to the rotor magnet. is provided with a float chamber communicating with the impeller chamber via a passage, the float chamber is communicated with the outlet, and the flow of fluid from the impeller chamber into the float chamber through the passage is stopped in the float chamber. The impeller is configured to include a float that engages with the housing when the impeller rotates with the impeller.

In the above configuration, when fluid is flowing from the inlet to the outlet via the impeller chamber, the passage and the float chamber, the float does not engage with the housing, so the impeller rotates together with the rotor magnet and its rotation. is detected by a magnetic sensor. When the flow of fluid from the inlet to the outlet stops, the float engages the housing and a braking force is applied to the impeller, stopping the impeller and rotor magnet.

(e) Examples Examples of the present invention will be described with reference to the drawings.

3 and 4, reference numeral 1 denotes a flow rate sensor according to this embodiment, which includes an impeller 21, a float 22 constituting a brake mechanism, and a rotor magnet 2.
3, a sensor body 30 forming an impeller chamber 31 for accommodating an impeller 21 and a float chamber 32 for accommodating a float, an inlet member 40 fixed to the sensor body and forming a fluid inlet, and an inlet member 40 for the sensor body. a housing 3 having an outlet member 50 fixed thereto and forming an outlet;
and a magnetoresistive element 6.

The rotating section 2 is composed of an impeller 21, a float 22, and a rotor magnet 23, which rotate as one body around the axes of upper and lower shafts 25 and 24. The impeller 21 and the rotor magnet are of known types, and the float 22 has an annular shape, for example, as shown in FIG. It is shaped to provide great buoyancy.

The float 22 acts as a brake plate that can be engaged with a portion of the housing, as will be described later, and
It is designed to apply braking force to 1.

The shaft 24 at the lower end of the rotary part 2 is vertically movable and rotatably supported by a bearing plate 35 attached to a bottom wall 34 formed integrally with the central annular peripheral wall 33 of the sensor body. Further, the shaft 25 at the upper end of the rotating part 2 has a bearing plate 26, and the upper part is supported so as to be movable in the vertical direction and rotatably by a bush 51 fitted to a projection on the central upper surface of the outlet member 50. has been done.

An impeller chamber 31 that accommodates the impeller 21 is formed in the sensor body 3 by a bottom wall 34 that is integrally formed at the lower part of the annular peripheral wall 33 . A vertical passage 37 is formed in the center of the wall 31a of the sensor body 30. A float chamber 32 is formed above the impeller chamber 31 and is defined by an outlet member 50 disposed above the sensor body main body 30 . A plurality of inflow nozzle holes 36 are formed in the peripheral wall 33 at an angle with respect to the radial direction so as to apply fluid to the blades of the impeller 21 at a substantially right angle.

An inlet member 40 having an inlet 41 facing vertically upward is fixed to the lower part of the sensor body 30.

An outlet member 50 having an outlet 52 is fixed to the upper part of the sensor body 30, and a magnetoresistive element 6 as a magnetic sensor is disposed adjacent to the rotor magnet 23. The rotating magnetic field generated by the net 23 is converted into an electric signal.

In the flow rate sensor 1 having the above configuration, fluid flows in from the inlet 41, passes around the lower surface of the bottom wall 34, and reaches the nozzle hole 36. The fluid passing through the nozzle hole 36 collides with the blades of the impeller 21 at almost right angles, causing the impeller 2
1 and flows into the float chamber 32 through the passage 37. The fluid is the brake plate or float 2
2 and enters the annular rectification chamber 39 through the rectification plate 38 having a plurality of orifices arranged around the upper part of the float chamber 32, and then reaches the outlet 52.

When the float 22 is pushed up to the top (the state shown in FIG. 4), the bearing plate 26, which is integral with the shaft 25, comes into contact with the lower end of the bush 51 and supports the upward thrust load.

Next, when the inflow of fluid stops, the buoyancy of the float 22 disappears, the rotating part 2 consisting of the impeller 21, the float 22, and the rotor magnet 23 descends, and the supporting surface 27 forming the lower surface of the float 22 becomes the upper surface of the partition wall 31a. The rotating part 2 is forcibly stopped by the friction between the two, and the rotating part 2 is forcibly stopped (the state shown in FIG. 3).

Furthermore, if the fluid flows backwards from the outlet 52 toward the inlet 41, the pressure on the outlet side is higher than the inlet side, so the float 22 is forced to move due to this pressure difference and its own weight. The support surface 27 comes into close contact with the upper surface of the radial partition wall 31a to stop the flow.

In the above embodiment, the float moves up and down together with the impeller and the rotor magnet, but as shown in FIG. Only 22' may be movable up and down relative to the impeller and rotate together with the impeller. Also, as shown in Figure 6, the float 2
2' and the rotor magnet 23'' are fixed, and the float and the impeller 21'' are connected by a sprun or the like so that the float and rotor magnet rotate together with the impeller, but may also be able to move up and down with respect to the impeller.

Alternatively, an inlet may be formed in the peripheral wall of the sensor body so that the fluid flows directly into the impeller chamber from the inlet.

(f) Effects (i) The flow rate sensor according to the present invention is equipped with a brake mechanism that applies a brake force to the float when the flow stops, so even if the frictional resistance of the bearing is reduced and responsiveness is improved, the falling response time will be shorter. can be shortened as shown by a in FIG.

(ii) In addition, in the flow rate sensor of the embodiment, the float floats up due to the flow of fluid and no thrust load is applied to the bearing, so the rotating part rotates easily and can operate even with a minute flow rate.
2 forms a check valve to prevent backflow of fluid.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a flow rate sensor according to the prior art.
FIG. 2 is a diagram showing the response characteristics of the flow rate sensor, and FIGS. 3 and 4 are cross-sectional views of one embodiment of the flow rate sensor according to the present invention, in which FIG. 3 shows a state with no flow rate,
FIG. 4 is a diagram showing a maximum flow rate state, FIG. 5 is an enlarged sectional view showing a modification of the rotating section, and FIG. 6 is an enlarged sectional view of another modification of the rotating section. 1, 1', 1'': Flow rate sensor, 2: Rotating part, 2
1, 21', 21'': Impeller, 22, 22', 2
2'': float, 23, 23', 23'': rotor magnet, 24, 25: shaft, 30: sensor body, 36: nozzle, 40: inlet member, 50: outlet member.

Claims (1)

[Scope of Claims] 1. A housing having an impeller chamber, an inlet and an outlet communicating with the impeller chamber, an impeller rotatably provided in the impeller chamber, and a housing configured to rotate together with the impeller. A rotor magnet provided,
A flow rate sensor comprising: a magnetic sensor provided in the housing adjacent to the rotor magnet;
The impeller chamber is in communication with the inlet, the housing is provided with a float chamber communicating with the impeller chamber via a passage, and the float chamber is in communication with the outlet;
A flow rate sensor characterized in that a float is rotatably provided in the float chamber and engages with the housing when the flow of fluid flowing from the impeller chamber into the float chamber through the passage is stopped. 2. The flow rate sensor according to claim 1, wherein the float is integrally fixed with the impeller and the rotor magnet so that they rotate together and move in the axial direction. 3. The flow rate sensor according to claim 1, wherein the impeller and the rotor magnet are integrally fixed, and the float rotates together with the impeller but is relatively movable in the axial direction. . 4. The flow rate sensor according to claim 1, wherein the float and the rotor magnet are integrally fixed so that they rotate together with the impeller but are movable relative to each other in the axial direction.