JP2007033080A - Water stream sensor and hot-water supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a water stream sensor which does not generate a mulfunction due to external disturbance. <P>SOLUTION: The water stream sensor 10 is provided with: a downstream side bearing member 26; an upstream side bearing member 40; and an impeller-like magnetic generation member 28 in a casing 25, and is also provided with two magnetic sensors 30, 31 at the outer circumferential part of the casing 25. The first magnetic sensor 30 and the second magnet sensor 31 are located off by 22.5° (π/8). Because of the positional relationship where, when the first magnetic sensor 30 is in a peak environment so as to be turned on, the second magnetic sensor 31 is in an environment of a transitional region so as to be switched from the on-state to the off-state or a transitional region so as to be switched from the off-state to the on-state, the first magnetic sensor 30 functions normally in an operational environment in which the second magnetic sensor 31 is unstable. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a water flow sensor used in a water heater or the like. The present invention also relates to a water heater provided with a water flow sensor.

  Water heaters that use gas or kerosene as fuel are widely used in ordinary households. A so-called instantaneous water heater is provided with a water flow sensor in a water channel including a heat exchanger. Then, when a flow of water occurs in the water channel passing through the heat exchanger by an operation such as opening the curan by the user, the above-described water flow sensor detects this, and combustion is started using this as a trigger.

Here, the water flow sensor mounted on the current water heater is a combination of a magnetized plastic mug turbine using an axial flow impeller structure and a magnetic sensor of a magnetoresistive element.
The water flow sensor described above can detect the actual flow rate in real time. In addition, since the impeller rotates continuously and continuously pulsates during running, there is no fear of failure such as locking in the ON state. Therefore, the water flow sensor described above plays a major role as a fail safe for the heart of the instantaneous water heater.

The structure of the water flow sensor is disclosed in, for example, the following patent document.
Japanese Utility Model Publication No. 61-8821

  Note that the water flow sensor described in Patent Document 1 has one impeller, and two magnetic sensors are provided in the casing of the impeller. In the idea of Patent Document 1, the reason for providing two magnetic sensors is to detect the direction of water flow.

  In recent years, there has been a demand for further miniaturization of water heaters. Therefore, the present inventors worked on miniaturization of the water heater, and designed and prototyped various structures. However, when testing the performance and safety of these water heaters, a mysterious phenomenon occurred. That is, there is a case where the water flow sensor generates a signal indicating that the water flow is detected although there is no water flow.

Prior to the elucidation of this phenomenon, the principle of the water flow sensor will be explained. The water flow sensor has an impeller disposed in a casing, and a magnet is attached to the impeller (in practice, the vane itself is magnetized. ing). A magnetic sensor using a magnetoresistive element is provided outside the casing. When water flows in the casing, the inner impeller rotates, and the magnetic poles magnetized on the impeller rotate to approach and separate from the magnetic sensor. As a result, a pulse signal is emitted from the magnetic sensor.
However, when the water heater is downsized, a pulse signal may be emitted from the magnetic sensor even though there is no water flow in the casing as described above.

  As a result of examining the cause, it was found that the pulse signal was emitted from the magnetoresistive element due to the influence of disturbance. That is, there are devices that generate an alternating magnetic field such as a pump in the water heater, and the distance between the water flow sensor and the device that generates the alternating magnetic field is reduced by downsizing the water heater. For this reason, the magnetic sensor of the water flow sensor is sensitive to an external alternating magnetic field and generates a pulse.

  Accordingly, the present invention focuses on the above-described problems of the prior art, and an object thereof is to develop a water flow sensor that does not cause malfunction due to disturbance. In addition, another object is to develop a water heater that does not cause malfunction.

In order to solve the above-described problems, it has been considered to arrange a plurality of magnetic sensors around the casing as in Patent Document 1 described above. That is, it was thought that false detection could be prevented simply by increasing the number of magnetic sensors. However, even if the water flow sensor having the configuration of Patent Document 1 is used, malfunction due to disturbance cannot be completely prevented.
Hereinafter, this reason will be described with reference to FIG. FIG. 21 is added to FIG. 3 of Patent Document 1.
The water flow sensor disclosed in Patent Document 1 is equipped with two magnetic sensors for the purpose of detecting the direction of the water flow as described above. For this reason, the magnetic sensor is disposed at such a position that when one of the magnetic sensors is in an on-peak peak environment, the other magnetic sensor has an off-state peak.
That is, the magnetic sensor has a peak that is turned on when the intensity of the component in a specific direction of the magnetic field becomes maximum. For example, the peak of the on state is obtained when the intensity of the Y direction component of the magnetic field is maximized and the component of the X direction is minimized. However, the direction of the magnetic field does not matter. Further, when the intensity of the X direction component of the magnetic field is maximized and the intensity of the Y direction component is minimized, the peak in the off state is changed.
Accordingly, when attention is paid to the first magnetic sensor as shown in FIG. 21, when the exposed magnetic field is maximum, specifically, at the peak A or valley B of the graph, Become. On the other hand, when C is zero, the peak is in the off state.
The same applies to the second magnetic sensor. When the peak A ′ or the valley B ′ of the graph, the second magnetic sensor is in an on-state peak environment, and at the zero C ′, the off-state peak.
As is clear from FIG. 21, when the water flow sensor disclosed in Patent Document 1 is in a peak environment where one of the magnetic sensors is in an on state, the other magnetic sensor is in a position where the peak is in an off state. Is provided.

By the way, considering the conditions under which a pulse signal is generated due to a disturbance, it can be said that the magnetic sensor is in a transition state from an on state to an off state, or in a transition state from an off state to an on state.
FIG. 1 is a schematic diagram showing a relationship between a magnetic sensor magnetized on an impeller (magnet generation member) and a magnetic sensor. FIG. 2 is a graph showing the relationship between the magnetic field intensity around the magnetic sensor and the output from the sensor when the impeller (magnetic generating member) rotates. FIG. 3A is a graph for explaining the influence of a disturbance when the first magnetic sensor is in a peak environment where the first magnetic sensor is turned on, and FIG. 3B is a disturbance when the first magnetic sensor is in a transition state. It is a graph explaining the influence of No .. FIG. 4 is a graph showing the relationship between the magnetic field intensity around the magnetic sensor and the output from the sensor when the impeller rotates by taking into account the X-direction component and the Y-direction component of the magnetic field.

In the model shown in FIG. 1, the impeller 1 has four blades 2 that are magnetized respectively. The magnetic sensor 3 detects the X-direction component and the Y-direction component of the magnetic field, and is turned on when the Y-direction component of the magnetic field is stronger than the X-direction component, and when the X-direction component is stronger than the magnetic field of the Y-direction component. Turns off.
In practice, it may be considered that the on-state is turned on when the Y-direction component of the magnetic field becomes a certain value or more, and the off-state is turned on when it falls below the certain value. However, the magnetic field intensity when switching from the on-state to the off-state and the magnetic field intensity switching from the off-state to the on-state are shifted due to hysteresis.

When attention is paid to one magnetic sensor, when the impeller 1 rotates, the Y-direction component of the magnetic field at the place where the magnetic sensor 3 is placed changes in a sinusoidal curve as shown in FIG.
As shown in FIG. 2, when the intensity of the Y direction component of the magnetic field exceeds a certain “on magnetic field”, the sensor output is turned on, and when the magnetic field intensity is less than the “off magnetic field”, which is weaker than the “on magnetic field”. The sensor output is turned off.
As shown in FIG. 1, when the blade piece 2 and the magnetic sensor 3 are in a linear positional relationship, the Y-direction component of the magnetic field in the vicinity of the magnetic sensor 3 becomes the strongest, resulting in a peak environment that is turned on.

Assuming that the impeller 1 rotates, the intensity of the magnetic field in the vicinity of the magnetic sensor 3 changes as shown in the graph of FIG.
As the blade approaches, the Y-direction component of the magnetic field becomes stronger, and the sensor output is turned on from point D that exceeds the ON magnetic field. Then, the blade piece 2 and the magnetic sensor 3 are in a linear positional relationship, and become the point E where the intensity of the magnetic field in the vicinity of the magnetic sensor 3 is the strongest, which is a peak environment that is turned on.

After this, the Y-direction component of the magnetic field gradually weakens, but the output of the sensor does not switch even when the on-magnetic field described above is reached (point F). The sensor output is switched from on to off only after reaching point G, which is an off magnetic field.
When the impeller 1 further rotates, it reaches an H point where the Y direction component of the magnetic field becomes zero. Point H is an off-state peak environment, and is a position rotated by 45 ° (π / 4) from the above-described on-state peak environment.
When the impeller 1 further rotates, the Y-direction component of the magnetic field gradually increases, and the sensor output is not switched even when the off-magnetic field is reached (point I). The sensor output is switched from off to on only after reaching point J, which is an on magnetic field.
When the impeller 1 further rotates, it becomes a peak environment where the Y direction component of the magnetic field is turned on (point K). Thereafter, the output of the sensor is switched from on to off by reaching point M, which is an off magnetic field.

  In the above-described series of positional relationships, in the case of the peak environment (E, K) in the on state, the influence of the magnet of the impeller 1 is strong, and the intensity of the Y direction component of the magnetic field passing through the magnetic sensor 3 is high. Because it is strong, the magnitude of the XY relationship of the magnetic field does not change even if it receives a slight disturbance. Briefly, since the strength of the Y direction component of the magnetic field is a certain level or more as shown in FIG. 3A, the environment in which the magnetic sensor 3 is placed even if the magnetic field strength fluctuates due to some disturbance. The magnetic field never falls below the off magnetic field. For this reason, the influence of disturbance is small in the case of the peak environment that is in the ON state.

  On the other hand, in the case of the off-peak environment (H), since the intensity of the X direction component of the magnetic field passing through the magnetic sensor 3 is strong, the magnitude of the XY relationship of the magnetic field does not change even if it receives a slight disturbance. .

On the other hand, when the X-direction component and the Y-direction component of the magnetic field passing through the magnetic sensor 3 are antagonistic, the on / off is switched by disturbance.
That is, in the transition state from the on state to the off state (near the hysteresis region) or in the transition state from the off state to the on state, a disturbance is superimposed on the magnetic field of the magnet of the impeller 1, and FIG. ) Will be switched on / off as shown. For example, assuming that the impeller 1 is stopped at the position of the transition state from the ON state to the OFF state, the magnetic sensor 3 is currently in the ON state. The environment of the magnetic sensor 3 falls below the off magnetic field, and the magnetic sensor 3 is switched from on to off. Since the disturbance is an alternating magnetic field generated by a pump, for example, the direction of the magnetic field due to the disturbance is rapidly switched. Therefore, what is turned off due to disturbance returns to the original on state at the next moment. And since this is repeated in a dizzying manner, a pulse signal is emitted from the magnetic sensor 3 and erroneously detects that there is water flow.

Specifically, as shown in FIG. 2, the positional relationship between the impeller 1 and the magnetic sensor 3 is intermediate between the peak environment in which the magnetic sensor 3 is turned on and the peak environment in which the magnetic sensor 3 is turned off. When this happens, the magnetic sensor 3 tends to malfunction. In the case of four impellers 1 as shown in FIG. 1, it is a position rotated by 22.5 ° (π / 8) from the peak environment in the ON state.
FIG. 4 illustrates the same operation with the X-direction component and the Y-direction component of the magnetic field taken into account. However, the conclusion is the same, and 22.5 ° (π / 8) from the peak environment that is in the ON state. It can be said that the magnetic sensor 3 is likely to malfunction when it is in the rotated position.
In FIG. 4, the absolute values of the strengths of the X-direction component and the Y-direction component of the magnetic field are graphed, and the line representing the negative strength of each direction component is inverted in the positive direction.

FIG. 5A is a graph for explaining the influence of a disturbance when the first magnetic sensor is in a peak environment where the first magnetic sensor is turned on, taking into account the X-direction component and the Y-direction component of the magnetic field, and FIG. 4 is a graph for explaining the influence of a disturbance when the first magnetic sensor is in a transition state, taking into account the X-direction component and the Y-direction component of the magnetic field.
5A, when the blade piece 2 and the magnetic sensor 3 have a linear positional relationship, the intensity of the Y direction component of the magnetic field near the magnetic sensor 3 and the X direction The difference between the intensity of the component is large, and even if the intensity of the Y direction component and the intensity of the X direction component are fluctuated due to a disturbance, the strength of both does not reverse.

  On the other hand, at the position where the blade is rotated 22.5 ° (π / 8), if the intensity of the Y-direction component and the intensity of the X-direction component change due to disturbance as shown in FIG. Is replaced. As a result, as shown in FIG. 5B, on / off is switched, and a pulse signal is emitted from the magnetic sensor 3, which erroneously detects that there is water flow.

Looking at the water flow sensor disclosed in Patent Document 1, as described above, when one magnetic sensor is in the peak environment where the on state is on, the other magnetic sensor is provided at a position where the off state peak is reached. ing.
Therefore, in the water flow sensor disclosed in Patent Document 1, when one magnetic sensor is in an on / off transition state, the other magnetic sensor is also in a transition state. Therefore, when the impeller stops at a specific position, the two magnetic sensors are both susceptible to disturbance. Therefore, the water flow sensor disclosed in Patent Document 1 cannot prevent erroneous detection due to disturbance.

Therefore, the present inventors have devised the arrangement of the two magnetic sensors so that at least one of them functions normally and prevents false detection.
The invention according to claim 1, which has been completed based on the above-described thinking, is a water flow sensor provided with a magnetism generating member that rotates by a water flow and a magnetic sensor, wherein there are two or more magnetic sensors, and the attachment of the magnetic sensor The position is a water flow sensor characterized in that the two magnetic sensors are not easily affected by the magnetic field based on the external environment in relation to the magnetism generating member.

  In the water flow sensor of the present invention, at least one magnetic sensor functions normally because the mounting position of the magnetic sensor is not easily affected by disturbance.

  The invention according to claim 2 is a water flow comprising a magnetism generating member that rotates by a water flow, and a magnetic sensor that is affected by magnetism generated by the magnetism generation member and that switches from an on state to an off state and from an off state to an on state. In the sensor, when there are two or more magnetic sensors and one of the magnetic sensors is in a peak environment where the on state is on, at least one other magnetic sensor is in a transition region or off state where the on state is switched to the off state. It is a water flow sensor characterized by being arranged in a positional relationship so as to be an environment of a transition region that switches from an on state to an on state.

  In the water flow sensor of the present invention, when there is a peak environment where one magnetic sensor is in the on state, the other at least one magnetic sensor is a transition region where the on state is switched from on to off, or a transition region where the off state is switched to the on state. It is arranged in such a positional relationship that it becomes the environment of. The positional relationship between the two is that when one of the magnetic sensors is easily affected by a disturbance, the other magnetic sensor is at a position that is not easily affected by the disturbance. Therefore, at least one magnetic sensor functions normally.

  According to a third aspect of the present invention, there is provided a water flow comprising a magnetism generating member that is rotated by a water flow, and a magnetic sensor that is affected by magnetism generated by the magnetism generating member and that switches from an on state to an off state and from an off state to an on state. In the sensor, there are two or more magnetic sensors, and when one magnetic sensor is in a peak environment where the on state is turned on, at least one other magnetic sensor is also turned off in the peak environment where the on state is turned on. It is a water flow sensor characterized by being arranged in a positional relationship that is not a peak environment.

  In the water flow sensor of the present invention, when one magnetic sensor is in the peak environment where the on state is turned on, the other at least one magnetic sensor is neither the peak environment where the on state is turned on nor the peak environment where the off state is turned on. Arranged in a positional relationship. If the magnetic sensors are arranged in this positional relationship, all the magnetic sensors do not come to a position where they are easily affected by disturbances at the same time. Therefore, at least one magnetic sensor functions normally.

According to a fourth aspect of the present invention, there is provided a water flow comprising a magnetism generating member that rotates by a water flow, and a magnetic sensor that is affected by magnetism generated by the magnetism generating member and that switches from an on state to an off state and from an off state to an on state. In the sensor, there are two or more magnetic sensors, and there is a phase shift when reaching a peak environment where two specific magnetic sensors are turned on. The water flow sensor is characterized by having a half phase of a period from a peak environment that is in a state to a peak environment that is in an off state.
Note that “about half-phase” means that an error of about plus or minus 5 ° is allowed.

  In the water flow sensor of the present invention, the magnetic sensor mounting positions are shifted from each other by a predetermined phase, so that all the magnetic sensors do not come to a position that is susceptible to disturbance at the same time, and at least one magnetic sensor is normal. To work.

The invention according to claim 5 is a water flow sensor provided with a magnetism generating member that rotates by a water flow and a magnetic sensor, wherein the magnetism generating member has one or a plurality of magnetic poles, and the magnetic sensor has two or more, The magnetic sensor is in a state where the magnetic pole is in the vicinity of the magnetism generating member at a constant cycle, and when the magnetic pole is in proximity to one magnetic sensor and in the state where the magnetic pole is in proximity to another magnetic sensor. The water flow sensor is characterized in that there is a deviation from time, and the deviation corresponds to [2 × π] / [number of magnetic poles × 2 × 2] rotation or an odd multiple of this rotation.
Note that “substantially” means that an error of about plus or minus 5 ° is allowed.

  Also for the water flow sensor of the present invention, the mounting positions of the magnetic sensors are shifted by a predetermined phase, so that all the magnetic sensors do not come to a position that is susceptible to disturbance at the same time, and at least one magnetic sensor is Functions normally.

  According to a sixth aspect of the present invention, in the water flow sensor provided with a magnetic generation member that rotates by a water flow and a magnetic sensor, there are two or more of the magnetic sensors, and the magnetic sensor is around the magnetic generation member. When the difference between the intensity of the unidirectional component of the magnetic field passing through the first magnetic sensor and the intensity of the directional component orthogonal thereto is the maximum, the unidirectional component of the magnetic field passing through at least one other magnetic sensor The water flow sensor is characterized in that the magnetic sensor is arranged in a positional relationship in which the difference between the strength and the strength of the direction component orthogonal to the strength is minimized.

  In the water flow sensor of the present invention, the difference between the intensity of a certain direction component (for example, Y direction component) of a magnetic field passing through one magnetic sensor and the intensity of a direction component (for example, X direction component) orthogonal thereto is maximum. At this time, the magnetic sensors are arranged in a positional relationship that minimizes the difference between the intensity of the constant direction component of the magnetic field passing through at least one other magnetic sensor and the direction component orthogonal thereto. Here, as described above, the magnetic sensor strongly influences the disturbance when the difference between the intensity of the constant direction component of the magnetic field passing through the magnetic sensor and the intensity of the direction component orthogonal thereto is minimal. receive. Conversely, when the difference between the two is maximum, the magnetic sensor is not easily affected by disturbance. With respect to the water flow sensor of the present invention as well, all the magnetic sensors do not come to a position that is susceptible to disturbance at the same time, and at least one magnetic sensor functions normally.

  The magnetism generating member is a rotating blade, and it is desirable that a magnet is provided on a part of the blade or the blade itself is magnetized.

  A plurality of magnetic sensors may be arranged on a plane substantially perpendicular to the water flow.

  Conversely, the plurality of magnetic sensors may be provided at positions shifted in the water flow direction (claim 9).

  The plurality of magnetic sensors are provided at positions shifted in the water flow direction, and the magnetic pole of the magnetism generating member has a predetermined length in the water flow direction or is divided in the water flow direction, and the position of the magnetic pole upstream of the water flow direction It can also be set as the structure which the position of the magnetic pole in the downstream of a water flow direction has shifted | deviated to the circumferential direction (Claim 10).

It is also recommended to determine that there is a water flow when two specific magnetic sensors detect changes in the magnetic field together (claim 11).
For example, a configuration may be considered in which a signal indicating that there is a water flow is output when two specific magnetic sensors simultaneously detect changes in the magnetic field.

  The invention of the water heater provided with the water flow sensor described above includes a heat exchanger, a combustion device, a water channel, a water flow sensor provided in the water channel, and one of the conditions is that the water flow sensor detects the water flow. In a water heater for combusting a combustion device, the water flow sensor is the water flow sensor according to any one of claims 1 to 10, and the water flow sensor detects water flow when two specific magnetic sensors detect a change in a magnetic field. It is a water heater characterized by burning a combustion apparatus as what detected this.

Here, the water heater is not limited to only having a hot water supply function, but also includes a device having a function of automatically dropping hot water into the bath, a function of chasing the hot water of the bath, and a function of heating the room. It is. In other words, devices having a function of creating hot water are collectively referred to as a water heater.
The water heater of the present invention does not cause a malfunction of the water flow sensor and is highly safe.

The water flow sensor of the present invention has an effect that there are few malfunctions due to disturbance. Therefore, a water heater etc. can be reduced in size.
In addition, the water heater of the present invention has an effect that malfunction does not occur even if it is downsized.

Hereinafter, embodiments of the present invention will be described.
FIG. 6 is an operation principle diagram of a water heater employing the water flow sensor according to the embodiment of the present invention. FIG. 7 is a front sectional view (a) and a side sectional view (b) of the water flow sensor according to the embodiment of the present invention. FIG. 8 is a perspective view of the water flow sensor according to the embodiment of the present invention. FIG. 9 is a perspective view showing the internal structure of the water flow sensor according to the embodiment of the present invention.

The water flow sensor 10 of the embodiment of the present invention is used as a part of a water heater 11 as shown in FIG. 6, for example. The basic structure of the water heater 11 is the same as that known in the art, and includes a heat exchanger 12 and a combustion device 13. Moreover, it has a series of water channels 17 from the water inlet 15 to the hot water outlet 16, and the heat exchanger 12 described above is interposed in the middle of the water channel.
The water heater 11 includes a bypass water channel 18 that bypasses the heat exchanger 12, and a proportional valve 20 is provided in the bypass water channel.
And the water flow sensor 10 of this embodiment is provided in the water channel leading to the heat exchanger 12.
The water heater 11 is ignited by the combustion device 13 when water flows through the water channel 17 by an operation such as opening the currant 21 and the water flow sensor 10 detects this.

As shown in FIG. 7, the water flow sensor 10 is provided with a downstream bearing member 26, an upstream bearing member 40, an impeller-like magnetism generating member 28, and a temperature sensor 29 in the casing 25. Are provided with two magnetic sensors 30 and 31.
The main body portion such as the casing 25 of the water flow sensor 10 is not different from the known one. That is, the casing 25 has an “L” shape like an elbow as shown in FIGS. 7 and 8, and includes a water inlet 32 and a water outlet 33, and the inside communicates.
Further, bearing holding portions 35 and 36 are provided inside the casing 25.
A temperature sensor 29 is attached to the curved portion of the casing 25.

  The downstream bearing member 26 is provided with a four-leaf fixed blade 41 and a shaft insertion hole 43. On the other hand, the upstream bearing member 40 has no fixed blades and is provided only with the shaft insertion hole 45.

The magnetism generating member 28 is a cylindrical axial flow impeller and includes four blades 37 around it. The four blades 37 are provided in a posture slightly inclined with respect to the axis. All of the blades 37 are magnetized and function as magnetic poles.
Shafts 46 and 47 protrude from both end faces of the magnetism generating member 28.

Further, the downstream bearing member 26 is placed on the bearing holding portion 35 of the casing 25, and the upstream bearing member 40 is placed on the bearing holding portion 36.
A shaft 46 protruding from the end of the magnetic generation member 28 is inserted into the shaft insertion hole 43 of the downstream bearing member 26, and a shaft 47 protruding from the other end of the magnetic generation member 28 is inserted into the upstream bearing member 40. The hole 45 is inserted. Accordingly, the impeller-like magnetism generating member 28 rotates without resistance in the casing 25.

The water flow sensor 10 of the present embodiment includes two magnetic sensors as a characteristic configuration. The magnetic sensors 30 and 31 themselves utilize a known magnetoresistive element.
FIG. 10 is a circuit diagram of the magnetic sensors 30 and 31 employed in the water flow sensor of the present invention.
Each of the magnetic sensors 30 and 31 has four magnetoresistive elements (MR elements), which are arranged in a predetermined layout and detect the X direction component and the Y direction component of the magnetic field.
The four magnetoresistive elements (MR elements) form a bridge circuit as shown in FIG. 10 and are connected to the operational amplifier. Therefore, an output corresponding to the difference in intensity between the X direction component and the Y direction component of the magnetic field is output from the operational amplifier.
The output of the operational amplifier is pulsed by a known A / D converter.

In the water flow sensor 10 of the present embodiment, the magnetic sensors 30 and 31 are provided at positions that are not easily affected by a magnetic field based on the external environment in relation to the magnetism generating member 28.
That is, in the water flow sensor 10 of the present embodiment, the first magnetic sensor 30 and the second magnetic sensor 31 are at a position 22.5 ° (π / 8) apart.

  FIG. 11 is a conceptual diagram illustrating the positional relationship between the magnetism generating member and the magnetic sensor in the water flow sensor according to the embodiment of the present invention. FIG. 12 is a graph showing the magnetic field intensity around the magnetic sensor when the impeller rotates in the water flow sensor according to the embodiment of the present invention.

  As shown in FIG. 12, the position separated by 22.5 ° (π / 8) is the intensity of the constant direction component (Y direction) of the magnetic field passing through the first magnetic sensor 30 and the direction component orthogonal to this ( When the difference between the intensity in the X direction) is maximum, the intensity of the constant direction component (Y direction) of the magnetic field passing through the magnetic sensor of the second magnetic sensor 31 and the intensity of the direction component (X direction) orthogonal thereto The positional relationship that minimizes the difference between

  In other words, this phase shift is a half phase of the period from the peak environment where the magnetic sensor is turned on to the peak environment where the magnetic sensor is turned off.

This position is such that when the first magnetic sensor 30 is in a peak environment where the on state is turned on, the second magnetic sensor 31 becomes a transition region where the on state is switched from on to off, or an environment of a transition region where the off state is switched to on. Because of the positional relationship, the first magnetic sensor 30 functions normally even if the second magnetic sensor 31 is in an unstable operating environment.
Conversely, even if the first magnetic sensor 30 is in an unstable operating environment, the second magnetic sensor 31 is in an environment where it functions normally.

FIG. 13 is a graph (a) showing a pulse output from each magnetic sensor when there is an actual water flow, and a graph showing a pulse assumed to be output from each magnetic sensor when subjected to a disturbance. (B).
When the water flow sensor of this embodiment is used in the water heater 1 as shown in FIG. 6 and water is actually passed through the water channel 17, a pulse output is output from each magnetic sensor as shown in FIG. 13 (a). Is done. That is, regular pulses are output from both. Both are out of phase by π / 8.

On the other hand, in the case of disturbance, as shown in FIG. 13B, a pulse is output only from either the first magnetic sensor 30 or the second magnetic sensor 31, and no pulse is output from the other.
Therefore, if it is determined that water has passed when both the first magnetic sensor 30 and the second magnetic sensor 31 have pulse outputs, malfunction due to disturbance can be prevented.
FIG. 14 is a flowchart showing the operation of the water heater in FIG.

  In the water heater 1 shown in FIG. 6, as shown in FIG. 14, when a pulse is detected in Step 1, this pulse is output from both the first magnetic sensor 30 and the second magnetic sensor 31 in Step 2. Determine whether or not. If pulses are output from both sides as shown in FIG. 12, it is determined that water is flowing in the water channel 17, and the flow proceeds to step 3 to calculate the flow rate. In addition, the water flow sensor 10 employ | adopted by this embodiment can detect the amount of passing water based on the pulse number per unit time.

  Thereafter, the routine proceeds to step 4 to start combustion, and thereafter, the amount of combustion is increased or decreased in the same manner as a known hot water heater to control the hot water temperature.

  In Step 2, if a pulse is issued only from one of the magnetic sensors 30, 31, it is considered that the magnetic sensor 30, 31 is malfunctioning due to a disturbance, so that the process waits without starting combustion (Step 5).

In the embodiment described above, the magnetism generating member 28 is a four-blade, and each of which is magnetized and provided with four magnetic poles is exemplified, but the number thereof is arbitrary. In the above-described embodiment, since the magnetism generating member 28 has four magnetic poles, the angle between the first magnetic sensor 30 and the second magnetic sensor 31 is appropriately π / 8. Of course, if the number of sensors is different, the arrangement angle of the magnetic sensor also changes.
The general formula for the arrangement angle of the magnetic sensor is [2 × π] / [number of magnetic poles × 2 × 2]. In the above-described embodiment, the magnetic sensors 30 and 31 are provided at the closest positions that are not easily affected by the magnetic field based on the external environment in relation to the magnetism generating member 28, but are further away from each other. It may be a position.
Accordingly, the angle may be an odd multiple of the magnetic sensor placement angle [2 × π] / [number of magnetic poles × 2 × 2].
When the magnetic sensor is arranged according to this equation, a deviation occurs between when the magnetic pole is close to the first magnetic sensor and when the magnetic pole is close to the second magnetic sensor. × π] / [number of magnetic poles × 2 × 2] equivalent to rotation or equivalent to an odd multiple of this.

For example, in the case of the water flow sensor 51 including the magnetism generating member 50 having six magnetic poles (blades) as shown in FIG. 15, the arrangement angle of the magnetic sensor is 15 ° (π / 12).
Here, FIG. 15 is a schematic diagram showing a relationship between a magnetic generation member and a magnetic sensor in a water flow sensor according to another embodiment of the present invention. FIG. 16 is a graph showing the magnetic field intensity around the magnetic sensor when the magnetism generating member 50 rotates in the water flow sensor of FIG.

In the above-described embodiment, two magnetic sensors are provided side by side on the same plane, but may be provided on different planes. That is, in the above-described embodiment, two magnetic sensors are arranged on a plane perpendicular to the water flow, and the magnetic sensors are at the same position in the water flow direction.
However, the present invention is not limited to this configuration, and a magnetic sensor may be provided at a position shifted in the water flow direction.

  FIG. 17 is a conceptual diagram illustrating a relationship between a magnetic generation member and a magnetic sensor in a water flow sensor according to another embodiment of the present invention. FIG. 18 is a front view, a plan view, and a cross-sectional view in a plane where the magnetic sensor is provided, showing the relationship between the magnetism generating member and the magnetic sensor in the water flow sensor of FIG. FIG. 19 is a conceptual diagram showing a relationship between a magnetic generation member and a magnetic sensor in a water flow sensor according to still another embodiment of the present invention.

  In the water flow sensor shown in FIG. 17, the magnetism generating member 52 has a total length longer than that of the previous embodiment. Further, the vane (magnetized) 53 has a considerable length, and is provided spirally on the outer periphery of the magnetism generating member 52. Therefore, in the magnetism generating member 52, there is an angle difference (an angular difference on the circumference, that is, an angle difference when viewed in plan) between the positions of the magnets on the front end side and the rear end side. This angle is, for example, about [2 × π] / [number of magnetic poles × 2 × 2]. If the number of magnetic poles is 4, this angle is 22.5 ° (π / 8).

  For example, when the magnetism generating member is in the posture shown in FIG. 18, the first magnetic sensor is in front of the blade, and the second magnetic sensor is at a position away from the blade by about 22.5 ° (π / 8). is there. Therefore, the magnetic sensors 30 and 31 are not simultaneously affected by the magnetic field based on the external environment.

In the embodiment shown in FIG. 17, the magnetic generating member having a long overall length is employed, but the same effect can be obtained even if the magnetic generating member is divided into a plurality of parts.
The water flow sensor shown in FIG. 19 includes two magnetism generating members 55 and 56, which are attached while being shifted by an angle of [2 × π] / [number of magnetic poles × 2 × 2].
Therefore, the magnetic sensors 30 and 31 are not simultaneously affected by the magnetic field based on the external environment.

  In the above-described embodiment, the circuits of the two magnetic sensors may be individual as shown in FIG. 10 described above. However, as shown in FIG. Good.

  In the embodiments described above, an example in which two magnetic sensors are arranged at ideal positions has been shown. However, depending on the installation space, there are cases where the magnetic sensors cannot always be arranged at ideal positions. However, at least when the first magnetic sensor is in an on-peak peak environment, the second magnetic sensor is placed in a positional relationship that is neither an on-peak peak environment nor an off-peak peak environment. The probability of false detection is extremely small.

Further, in the above-described embodiment, the magnetism generating member 28 includes the inclined blade 37, and the magnetic force generation member 28 is rotated by applying a straight water flow to the inclined blade 37 to generate a circumferential component force. The same effect can be obtained by using the blade provided with the.
Further, the magnetism generating member 28 may be rotated by turning the water flow. That is, a fixed blade provided with an inclination angle and a twist is provided on the upstream side of the magnetism generating member. The straightly flowing water flow turns into a swirl flow along the fixed blades, and the magnetism generating member 28 is rotated by this swirl flow. When this configuration is adopted, the blades of the magnetism generating member 28 may be linear.

It is a schematic diagram which shows the relationship between the magnetic pole magnetized by the impeller (magnetism generating member) and a magnetic sensor. It is a graph which shows the relationship between the magnetic field intensity around a magnetic sensor when an impeller (magnetism generating member) rotates, and the output from a sensor. FIG. 3A is a graph for explaining the influence of a disturbance when the first magnetic sensor is in a peak environment where the first magnetic sensor is turned on, and FIG. 3B is a disturbance when the first magnetic sensor is in a transition state. It is a graph explaining the influence of No .. It is a graph which shows the relationship between the magnetic field intensity of the magnetic sensor periphery when an impeller rotates considering the X direction component and Y direction component of a magnetic field, and the output from a sensor. (A) is a graph for explaining the influence of a disturbance when the first magnetic sensor is in a peak environment where the first magnetic sensor is turned on, taking into account the X-direction component and the Y-direction component of the magnetic field, and (b) is a magnetic field. It is a graph explaining the influence of the disturbance when the 1st magnetic sensor is in a transition state in consideration of X direction component and Y direction component of. It is an operation | movement principle figure of the water heater which employ | adopted the water flow sensor of embodiment of this invention. It is front sectional drawing (a) and side sectional drawing (b) of the water flow sensor of embodiment of this invention. It is a perspective view of the water flow sensor of the embodiment of the present invention. It is a perspective view which shows the internal structure of the water flow sensor of embodiment of this invention. It is a circuit diagram of the magnetic sensor employ | adopted with the water flow sensor of this invention. It is a conceptual diagram explaining the positional relationship of the magnetism generation member and magnetic sensor in the water flow sensor of embodiment of this invention. It is a graph which shows the magnetic field intensity of a magnetic sensor periphery when an impeller rotates in the water flow sensor of embodiment of this invention. A graph (a) showing a pulse output from each magnetic sensor when there is an actual water flow, and a graph (b) showing a pulse assumed to be output from each magnetic sensor when subjected to a disturbance. is there. It is a flowchart which shows operation | movement of the water heater of FIG. It is a schematic diagram which shows the relationship between a magnetic generation member and a magnetic sensor about the water flow sensor of other embodiment of this invention. It is a graph which shows the magnetic field intensity around a magnetic sensor when a magnetism generating member rotates in the water flow sensor of FIG. It is a conceptual diagram which shows the relationship between the magnetism generation member and magnetic sensor in the water flow sensor of other embodiment of this invention. FIG. 18 is a front view, a plan view, and a cross-sectional view in a plane on which a magnetic sensor is provided, showing a relationship between a magnetic generation member and a magnetic sensor in the water flow sensor of FIG. 17. It is a conceptual diagram which shows the relationship between the magnetic generation member and magnetic sensor in the water flow sensor of further another embodiment of this invention. It is a circuit diagram of the magnetic sensor employ | adopted by other embodiment of this invention. This is added to FIG. 3 of Patent Document 1.

Explanation of symbols

2 Blade 3 Magnetic sensor 10 Water flow sensor 11 Water heater 12 Heat exchanger 13 Combustion device 17 Water passage 28 Magnetic generating member 30 Magnetic sensor 31 Magnetic sensor 37 Blade 50 Magnetic generating member 51 Magnetic sensor 52 Magnetic generating member 53 Blade 55 Magnetic generating member 56 Magnetic generating member

Claims (12)

  In a water flow sensor equipped with a magnetic generation member that rotates by a water flow and a magnetic sensor, there are two or more magnetic sensors, and the mounting position of the magnetic sensor is the influence of a magnetic field based on the external environment in relation to the magnetic generation member. A water flow sensor characterized in that the two magnetic sensors are difficult to receive at the same time.   In the water flow sensor comprising a magnetism generating member that is rotated by a water flow and a magnetic sensor that is affected by the magnetism generated by the magnetism generating member and switches from an on state to an off state and from an off state to an on state, the magnetic sensor includes two magnetic sensors. When there is a peak environment where one magnetic sensor is in the on state, the transition region where the other at least one magnetic sensor is switched from the on state to the off state, or the environment of the transition region where the off state is switched to the on state A water flow sensor characterized by being arranged in such a positional relationship.   In the water flow sensor comprising a magnetism generating member that is rotated by a water flow and a magnetic sensor that is affected by the magnetism generated by the magnetism generating member and switches from an on state to an off state and from an off state to an on state, the magnetic sensor includes two magnetic sensors. When there is a peak environment where one magnetic sensor is in the ON state, at least one other magnetic sensor is placed in a positional relationship that is neither the peak environment in the ON state nor the peak environment in the OFF state A water flow sensor characterized by being made.   In the water flow sensor comprising a magnetism generating member that is rotated by a water flow and a magnetic sensor that is affected by the magnetism generated by the magnetism generating member and switches from an on state to an off state and from an off state to an on state, the magnetic sensor includes two magnetic sensors. With the above, there is a phase shift when reaching the peak environment where two specific magnetic sensors are turned on, and the phase shift is off from the peak environment where one magnetic sensor is turned on The water flow sensor is characterized in that it is about half a phase of the peak environment.   In a water flow sensor having a magnetism generating member that rotates by a water flow and a magnetic sensor, the magnetism generating member has one or a plurality of magnetic poles, and there are two or more magnetic sensors, and the magnetic sensor is located around the magnetism generating member. In this case, the magnetic poles are close to each other with a certain period, and there is a difference between when the magnetic poles are close to one magnetic sensor and when the magnetic poles are close to another magnetic sensor, The deviation is substantially equivalent to [2 × π] / [number of magnetic poles × 2 × 2] rotation or an odd multiple of this rotation.   In a water flow sensor provided with a magnetism generating member that rotates by a water flow and a magnetic sensor, there are two or more magnetic sensors, and the magnetic sensor is located around the magnetism generating member and has a magnetic field that passes through one magnetic sensor. When the difference between the intensity of the unidirectional component and the intensity of the directional component orthogonal thereto is the maximum, the intensity of the unidirectional component of the magnetic field passing through at least one other magnetic sensor and the direction orthogonal thereto A water flow sensor characterized in that a magnetic sensor is arranged in a positional relationship that minimizes the difference between the strengths of the components.   The water flow sensor according to any one of claims 1 to 6, wherein the magnetism generating member is a rotating blade, and a magnet is provided on a part of the blade or magnetized on the blade itself.   The water flow sensor according to claim 1, wherein the plurality of magnetic sensors are arranged on a plane substantially perpendicular to the water flow.   The water flow sensor according to any one of claims 1 to 8, wherein the plurality of magnetic sensors are provided at positions shifted in the water flow direction.   The plurality of magnetic sensors are provided at positions shifted in the water flow direction, and the magnetic pole of the magnetism generating member has a predetermined length in the water flow direction or is divided in the water flow direction. The water flow sensor according to claim 1, wherein the position of the magnetic pole on the downstream side in the direction is shifted in the circumferential direction.   The water flow sensor according to any one of claims 1 to 10, wherein when two specific magnetic sensors detect a change in a magnetic field together, it is determined that there is a water flow.   A water heater comprising a heat exchanger, a combustion device, a water channel, and a water flow sensor provided in the water channel, wherein the water flow sensor detects the water flow, and burns the combustion device as one of the conditions. 11. The water flow sensor according to claim 1, wherein when the two specific magnetic sensors detect a change in the magnetic field, the water flow sensor detects the water flow and combusts the combustion apparatus. A water heater.

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