JP4906812B2 - Water level detection device and cooking device - Google Patents

Description

  The present invention relates to a water level detection device for detecting a water level in a water tank and a cooking device provided with the water level detection device.

  Conventionally, as a water level detection device for detecting the water level in a tank, for example, “the prism 20 of the ink tank reflects the light incident from the outside when there is no liquid in the liquid chamber, but there is liquid in the liquid chamber. Has a function of not reflecting light incident from the outside, and has a square cross section with a side of 40 mm and a thickness of 1.7 mm in a rectangular parallelepiped and measures the optical characteristics according to the standard according to JIS K7136. The ratio is 80% or more and the haze value is 75% or more and 85% or less, which is equivalent to the optical characteristics "(for example, see Patent Document 1).

JP 2005-41183 A (summary)

The water level detection device proposed in the above-mentioned Patent Document 1 is for detecting the remaining amount of ink in the printing press, and only needs to be able to detect ink depletion. There is no need to provide a detection device.
On the other hand, in the water level detection device applied to the condensate by directing the steam generated in the rice cooker to the water tank and dissipating it in the cooling water, the initial water level and capacity of the water volume essential for steam cooling are It is necessary to detect a plurality of water levels such as the full water level before exceeding, and the water level detection device of Patent Document 1 described above cannot be applied as it is. In addition, since the water level detection device is disposed in the rice cooker, the temperature rises to 60 ° C. and it is also a humid environment with rice cooking steam. Since it was repeated, the state of the water tank (installation state, dirt, deterioration, etc.) varied. Under such circumstances, it has been desired to develop a mechanism for measuring the water level of the water tank with high accuracy, particularly a structure for improving the measurement accuracy of a portion related to the mounting structure of the light emitting element and the light receiving element.

  This invention is made | formed in view of such a condition, It aims at providing the water level detection apparatus which made it possible to measure the water level of a water tank accurately, and a heating cooker provided with the same. .

The water level detection device according to the present invention includes: a light emitting unit that emits light toward the reflection / transmission part in a water tank including a reflection / transmission part whose light reflection amount and transmission amount change depending on the presence or absence of liquid; and A water level detecting means provided with a light receiving means for receiving light through the reflection / transmission section and generating and outputting a signal corresponding to the amount of light, and light from the light emitting means and light input to the light receiving means, supporting the water level detecting means. And a water level determination means for determining the water level stored in the water tank based on a signal from the water level detection means , and the support Openings are formed at positions opposed to the light emitting means and the light receiving means, respectively, and the opening of the support has a truncated cone shape whose diameter decreases toward the water tank .

According to the present invention, so-called stray light can be reduced by guiding the light from the light emitting means and the light input to the light receiving means by the opening of the support . For this reason, it is possible to accurately measure the water level of the water tank.

Embodiment 1 FIG.
FIG. 1 is a side view showing a state in which the internal configuration of heating cooker 100 according to Embodiment 1 of the present invention is viewed from the side.
The heating cooker 100 cooks the heated object by heating the inner pot containing the heated object (rice, water, etc.) with a heating means such as an induction heating coil, and collects the steam generated at that time in a water tank. To do. In the following drawings including FIG. 1, the relationship between the sizes of the constituent members may be different from the actual one.

  The heating cooker 100 is covered with a lid 3 so that the top surface thereof can be freely opened and closed, and the main body 1 in which the rice cooker 2 and the water tank 7 are detachably stored, and the heated object to be cooked are placed. A rice cooker 2 that is detachably stored in the lid, a lid 3 that covers the upper surface of the main body 1 through a hinge portion (not shown) pivotally supported on the upper rear portion of the main body 1, and the inside of the lid 3 Is attached detachably and covers the upper opening of the rice cooker 2 so as to be openable and closable, the heating body 5 such as an induction heating coil for heating the rice cooker 2, and a predetermined amount of water are stored and steam is stored. It is composed of a water tank 7 that recovers steam by cooling and condensing water, and a steam pipe 6 that connects the rice cooker 2 and the water tank 7 and conducts steam.

  The main body 1 has an opening on the upper surface, and stores the heating body 5 in addition to the rice cooker 2 and the water tank 7. The rice cooker 2 has an opening on the top surface, and the opening is covered with the inner lid 4 so that the inside is sealed. The lid 3 covers the upper surface of the main body 1 so as to be freely opened and closed when a user operates an open / close switch or the like (not shown). In addition, a vapor pipe 6 is detachably attached to the lid 3. The inner lid 4 closes the inside of the rice cooker 2 by closing the upper opening of the rice cooker 2 during cooking. The heating body 5 is disposed on the bottom surface side of the rice cooker 2 and heats the rice cooker 2 to cook or keep warm by being energized.

  The steam pipe 6 is connected to a steam introduction pipe 13 having one end (the right end portion on the paper surface) connected to the substantially central portion of the inner lid 4 and the other end (the left end portion on the paper surface) inserted into the water tank 7. The rice cooker 2 and the water tank 7 are connected. The water tank 7 stores a predetermined amount of water therein, and cools and collects the steam circulated through the steam pipe 6. The water tank 7 is stored beside the position where the rice cooker 2 is stored. The water tank 7 has an upper surface formed with an opening, and has a tank lid 12 that detachably covers the opening. Further, a vapor introduction pipe 13 is fixed to the tank lid 12 so as to penetrate therethrough.

  One end (upper end) of the steam introduction pipe 13 is detachably connected to the steam pipe 6 and the other end (lower end) thereof is located inside the water tank 7 in a state where the tank lid 12 is attached to the water tank 7. It is like that. That is, the steam pipe 6 is separated from the steam introduction pipe 13 when the lid 3 is opened, and the steam pipe 6 is connected to the steam introduction pipe 13 when the lid 3 is closed. The steam pipe 6 and the steam introduction pipe 13 function as a steam guide path that guides the steam generated during rice cooking into the water tank 7, and the water tank 7 uses the water that has flowed in via the steam introduction pipe 13 as water. Condensation is performed and the recovered water 9 is stored, and these constitute a steam recovery device.

  Also, in the main body 1, a determination control means 11 that determines the water level of the water tank 7 and controls the energization of the heating body 5, and a water level detection that detects the water level of the recovered water 9 stored in the water tank 7. Means (water level detection sensor) 8 are provided. The determination control unit 11 is disposed on the bottom surface of the main body 1 and below the heating body 5, and controls energization to the heating body 5 based on a signal output from the water level detection unit 8. The water level detection means 8 is provided facing the side surface of the water tank 7 and detects whether or not the water level of the recovered water 9 in the water tank 7 is equal to or higher than a preset water level. The water level detection means 8 outputs the output signal to the determination control means 11, and the determination control means 11 determines whether the water level of the recovered water 9 has reached a certain set water level based on the output of the water level detection means 8. Determine. Thus, the water level detection means 8 and the determination control means 11 constitute the water level detection device 20 of the present invention, and details thereof will be described with reference to FIG.

FIG. 2 is a block diagram showing the configuration of the water level detection device 20.
The water level detection device 20 is composed of the water level detection means 8 and the determination control means 11 as described above. The water level detection means 8 includes a light emitting means 21 and a light receiving means 22 for emitting and receiving light via the water tank 7 (details of the arrangement of both will be described in detail in FIG. 3 and the like). In the present embodiment, the light emitting means 21 and the light receiving means 22 are provided with three sets of light emitting elements and light receiving elements in the height direction (see FIG. 1).
Further, the determination control means 11 includes, as a configuration of the water level detection device 20, an amplifier 23 that amplifies the output of the light receiving means 22 and a control / signal processing circuit 24 that performs signal processing on the output of the amplifier 23. This control / signal processing circuit 24 corresponds to the water level determination means of the present invention, and is constituted by, for example, a microcomputer.
Further, the water level detection device 20 further includes a display 25 that displays the calculation result by the control / signal processing circuit 24. The display 25 is composed of, for example, a lamp or a liquid crystal display, and is installed at a position located above the water tank 7 like the lid 3 so that when the water tank 7 is taken in and out, the water spills out. Even if something happens, the water is kept away.

  In the water level detection device 20 having such a configuration, the control / signal processing circuit 24 supplies a light emission command signal to the light emitting means 21 and outputs a light reception command signal to the light receiving means 22. As a result, the light emitting means 21 emits light, and the light receiving means 22 receives light through the water tank 7. The amount of light received by the light receiving means 22 differs depending on whether or not there is recovered water in the water tank 7 at a position corresponding to the part where the light emitting means 21 and the light receiving means 22 are installed (when water is present). Light reception amount is small, and when there is no water, light reception amount is large). The output of the light receiving means 22 is amplified by the amplifier 23 and then supplied to the control / signal processing circuit 24. The control / signal processing circuit 24 determines whether or not the signal from the amplifier 23 corresponds to a predetermined water level, and for example, a message that prompts the rice cooker to stop and drain the recovered water 9 according to the determined water level. Is displayed on the display 25 to notify the user. The notification to the user may be performed by voice by providing voice generation means, for example.

  Next, the mounting structure of the water level detection means 8 will be described.

FIG. 3 is an explanatory view showing the relationship between the water tank 7 and the water level detecting means 8 (however, only one set of the light emitting element and the light receiving element is shown in FIG. 4 is a cross-sectional view thereof.
The water tank 7 is made of a light-transmitting material (for example, polystyrene), and a concave portion 71 is formed on a part of the side surface (the side surface on the main body 1 side in the longitudinal direction of the water tank 7). Yes. The concave portion 71 is configured to have a predetermined depth along the height direction of the water tank 7 (for example, a trapezoid in a plan view), two bent portions (incident surface, outgoing surface) 71a and 71b, The transmission part 71c which ties. The recess 71 functions as the reflection / transmission part 72 of the present invention. Note that the reflection / transmission unit 72 is not limited to the above-described form, and may be, for example, a triangular shape in a plan view.
The water tank 7 is configured in this way, and when the light is projected onto the bent portion 71a outside the water tank 7, the difference in refractive index (water and air) due to the presence or absence of water is detected inside the water tank 7. It is formed so that light is reflected or transmitted and the optical path is changed. When there is no water, reflected light is obtained from the bent portions 71a and 71b. As an example of the shape of the recess 71, a tank thickness of 2.0 mm, a bent portion angle of 45 ° (inside), 10 ° (outside), a transmission portion distance of 20 mm, and a transmission portion thickness of 3.0 mm are configured.

A water level detection means 8 is arranged at a position facing the recess 71 of the water tank 7 and corresponding to the measured water level. In the water level detection means 8, the light emitting element 21 a and the light receiving element 22 a are attached to the substrate 31. The light emitting element 21 a emits infrared light, for example, and the light receiving element 22 a has sensitivity corresponding to the wavelength, and receives infrared light that passes through the water tank 7.
Window members 33 and 34 are provided in the housing 1 a of the main body 1 interposed between the water level detection means 8 (light emitting element 21 a and light receiving element 22 a) and the water tank 7. For example, the window members 33 and 34 transmit light of 80% or more in the wavelength band of light (infrared rays) used for water level detection of the light emitting element 21a and the light receiving element 22a, and in other wavelengths, particularly in the visible light wavelength band. A member having a light transmittance of 20% or less is used. By using such window members 33 and 34, the user can not see the water level detection means 8 installed in the main body 1 and the design can be improved.

Next, the reflection and transmission of light in the water level detection means 8 and the water tank 7 will be described with reference to FIG.
When the light emitting element 21a receives the light emission command signal from the control / signal processing circuit 24, the light emitting element 21a emits infrared light, which enters the bent portion 71a, and when there is no recovered water 9 at the detected water level in the water tank 7, the bent portion The light is reflected by the inner surface of 71a and reaches the bent portion 71b via the transmission portion 71c, and is reflected by the inner surface of the bent portion 71b and exits from the bent portion 71b. The infrared light from the bent portion 71 b is received by the light receiving element 22 a, and the output of the light receiving element 22 a is transmitted to the control / signal processing circuit 24 via the amplifier 23. At this time, the amount of light received by the light receiving element 22a is large, and it is thereby understood that the recovered water 9 has not reached the detected water level. Further, when there is recovered water 9 at the detected water level in the water tank 7, the infrared light from the light emitting element 21a is transmitted through the bent portions 71a and 71b, and the amount of light received by the light receiving element 22a is small. Is understood to have reached the detected water level.

As described above, in the first embodiment, since the water level detecting means 8 including the light emitting means 21 and the light receiving means 22 is attached to the substrate 31, the relative position between the light emitting means 21 and the light receiving means 22 is accurately positioned. be able to. In addition, since the water level detection means 8 is attached to the substrate 31, the attachment position can be accurately positioned when attaching to the housing or the like. For this reason, it is possible to accurately measure the water level of the water tank. Also, when detecting a plurality of water levels, a plurality of sets of light emitting means 21 and light receiving means 22 can be easily provided.
Further, window members 33 and 34 are provided in the housing 1a of the main body 1 interposed between the water level detection means 8 and the water tank 7, and the window members 33 and 34 have a transmittance in the wavelength band of light used for water level detection. In comparison with the transmittance in the wavelength band of the visible light region, since the member having the former transmittance larger than the latter transmittance is used, the user cannot see the water level detecting means 8 installed in the main body 1. The design is enhanced.

Embodiment 2. FIG.
FIG. 5 is a configuration diagram of a water level detection device according to Embodiment 2 of the present invention. 4 is characterized in that a support tool 35 is provided.
The support 35 is interposed between the casing 1a and the water level detection means 8, and supports the water level detection means 8 and attaches it to the casing 1a. Openings 36a and 37a functioning as the optical path of the present invention are formed in the support 35 at positions facing the light emitting element 21a and the light receiving element 22a. The openings 36a and 37a are in the shape of a truncated cone, and the larger diameter of the truncated cone is, for example, a size enough to cover the light emitting element 21a and the light receiving element 22a, and decreases toward the housing 1a side. It is formed to become. A light-absorbing member or paint made of a carbon material such as carbon black is applied to the inner walls of the openings 36a and 37a and the periphery of the window members 33 and 34. In the following description, an example in which a paint is applied will be described, and it will be referred to as a light absorbing coating film 51. In this way, by providing the light absorbing coating film 51 on the inner walls of the openings 36a and 37a and the periphery of the window members 33 and 34, it is possible to suppress the reflected light at the place where light hits other than for detecting the members around the optical path. This reduces stray light and reduces false positives.

  In the second embodiment, as described above, since the water level detection means 8 is attached to the casing 1a via the support 33, the positioning of the water level detection means 8, the water tank 7 and the casing 1a is performed. Made with high accuracy. Further, the infrared light from the light emitting element 21 a of the water level detection means 8 is emitted to the water tank 7 side through the opening 36 a of the support 33, and the reflected light from the water tank 7 side is the opening of the support 35. The light is incident on the light receiving element 22a through 37a, and the light of each element of the light emitting element 21a and the light receiving element 22a is guided by the openings 36a and 37a functioning as optical paths, so that the so-called stray light is reduced and the light receiving element 22a is detected. Accuracy is improved. In addition, since the light absorbing coating film 51 is formed at a place where light hits other than for detecting members around the optical path, the reflected light is suppressed and stray light is reduced, and the detection accuracy of the light receiving element 22a is improved. The water level detection accuracy of the water level detection device 20 is improved.

Embodiment 3 FIG.
FIG. 6 is a configuration diagram of water level detection means according to Embodiment 3 of the present invention. In relation to the configuration of FIG. 4 described above, there is a feature in that cylindrical support members 38a and 39a are provided.
The supports 38a and 39a are interposed between the casing 1a and the water level detecting means 8 and attach the water level detecting means 8 to the casing 1a, and are disposed at positions facing the light emitting element 21a and the light receiving element 22a. Is done. The support tools 38a and 39a are made of a light-transmitting member, and the side surfaces thereof are formed as mirror surfaces, or the film 52 made of a paint having a refractive index lower than that of the support tool main body is formed on the side surfaces thereof. The light to the side of the element is reflected forward.

  In the third embodiment, as described above, the water level detection means 8 is attached to the substrate 31 and is attached to the housing 1a via the support tools 38a and 39a, which is the same as the above-described embodiment. In addition, the water level detecting means 8, the water tank 7 and the housing 1a are positioned with high accuracy. Infrared light from the light emitting element 21a of the water level detecting means 8 is emitted to the water tank 7 side via a support 38a that functions as an optical path, and reflected light from the water tank 7 side is supported by an optical path. The light is incident on the light receiving element 22a via 39a, so-called stray light is reduced, and the detection accuracy of the light receiving element 22a is improved. Further, the above-described configuration (mirror surface, film 52) of the support tools 38a and 39a reflects light forward to the side of each element of the light emitting element 21a and the light receiving element 22a, and light is received by increasing the output. The detection accuracy of the element 22a is improved, and the water level detection accuracy of the water level detection device 20 is improved.

Embodiment 4 FIG.
FIG. 7 is a configuration diagram of a water level detection unit according to Embodiment 4 of the present invention. In relation to the configuration of FIG. 5 described above, there is a feature in that a mechanism for engaging and positioning the casing 1a and the support 33 is provided. Here, the convex part 41 is formed in the housing | casing 1a, and the recessed part 42 is formed in the support tool 33 (in addition, an unevenness | corrugation may be the contrary).

In the fourth embodiment, the concave portion 42 of the support tool 33 is fitted into the convex portion 41 and positioned in the housing 1a so that the support device 35 can be attached to the housing 1a. Can be suppressed, and the mounting accuracy can be improved. The support 35 and the water level detecting means 8 may be assembled in advance and then attached to the housing 1a. Alternatively, the water level detecting means 8 may be attached after the support 35 is attached to the housing 1a. You may make it attach.
Moreover, the structure for positioning the support tool 35 and the water level detection means 8 is not limited to the above example, and may be in any other form as long as both are engaged.

Embodiment 5 FIG.
FIG. 8 is a configuration diagram of water level detection means according to the fifth embodiment of the present invention. 4 is characterized in that a bottomed cylindrical support tool 45 is provided.
The support 45 has a cylindrical shape with a bottom, and an upper flange is provided with a mounting flange, and the light emitting element 21a or the light receiving element 22a is attached to the inner bottom. The support 45 is attached to the substrate 31 with the light emitting element 21a or the light receiving element 22a attached to the substrate 31.

  In the fifth embodiment, the light emitting element 21a or the light receiving element 22a is attached to the support 45 and the substrate 31, respectively. Therefore, the positioning of the water level detecting means 8, the water tank 7 and the housing 1a is highly accurate. To be made. The infrared light from the light emitting element 21a of the water level detecting means 8 is emitted to the water tank 7 side through one cylindrical support 45, and the reflected light from the water tank 7 side is the other cylindrical shape. Since the light is incident on the light receiving element 22a through the support 45, the effective range is limited by blocking the light on the side surfaces of the light emitting element 21a and the light receiving element 22a, and the light wraparound can be blocked. For this reason, the detection accuracy of the light receiving element 22a is improved, and the water level detection accuracy of the water level detection device 20 is improved.

Embodiment 6 FIG.
9 (a), 9 (b), and 9 (c) are a transparent perspective view (part of the configuration is omitted) of the heating cooker according to the sixth embodiment of the present invention, a perspective view with the lid 3 removed, and a main body FIG. 2 is a transparent perspective view in a state where a water tank 7 is removed from 1.
In the sixth embodiment, a convex portion 46 is formed on the side portion of the main body 1 on the water tank 7 side, and the lid 3 is engaged (latched) on the upper surface side of the convex portion 46. For this purpose, an upper lid stopper 47 is provided, and an engaging member (not shown) provided on the lid body 3 is engaged with the upper lid stopper 47 so that the lid body 3 is locked to the main body 1. Further, the water level detecting means 8 of the above-described embodiment is housed under the upper lid stopper 47, and the window members 33, 34 of the above-described embodiment are attached to the casing 1a of the convex portion 46. ing. The water tank 7 is provided with a recess 71 for detecting the water level at a position facing the window members 33 and 34.

  In the sixth embodiment, as described above, the water level detection means 8 is accommodated in the convex portion 46 provided with the upper lid stopper 47, and the water tank 7 is also detected at a position corresponding to it. For this reason, the number of concave and convex portions of the water tank 7 is reduced, the cleanability is improved, and the hygiene and comfortable feeling of use are enhanced. Further, since the shape of the water tank 7 is simplified, productivity and user-friendliness are improved. Moreover, since the recessed part 71 which comprises the reflective transmission part 72 provided in the water tank 7 is formed in the intermediate position of the width direction of the water tank 7 as shown in figure, for example, the installation state of the water tank 7 is a little slanted. Even if it is, the water level does not fluctuate greatly, and the water level of the water tank can be accurately measured.

  In addition, this invention is not limited to said Embodiment 1-Embodiment 6, You may make it comprise a water level detection apparatus or a heating cooker even if these Embodiments are combined suitably.

It is a side view which shows the state which looked at the internal structure of the heating cooker which concerns on Embodiment 1 of this invention from the side surface. It is the block diagram which showed the structure of the water level detection apparatus. It is explanatory drawing which showed the relationship between a water tank and a water level detection means. It is a cross-sectional view of FIG. It is a block diagram of the water level detection means which concerns on Embodiment 2 of this invention. It is a block diagram of the water level detection means which concerns on Embodiment 3 of this invention. It is a block diagram of the water level detection means which concerns on Embodiment 4 of this invention. It is a block diagram of the water level detection means which concerns on Embodiment 5 of this invention. (A) (b) (c) is a transparent perspective view of the heating cooker according to Embodiment 6 of the present invention), a perspective view with the lid removed, and a transmission with the water tank 7 removed from the main body It is a perspective view.

Explanation of symbols

 DESCRIPTION OF SYMBOLS 1 Main body, 1a Case, 2 Rice cooker, 3 Lid body, 4 Inner lid, 5 Heating body, 6 Steam pipe, 7 Water tank, 8 Water level detection means, 9 Collected water, 11 Judgment control means, 12 Tank lid, 13 Steam introduction pipe, 20 Water level detection device, 21 Light emitting means, 21a Light emitting element, 22 Light receiving means, 22a Light receiving element, 23 Amplifier, 24 Control / signal processing circuit, 25 Display, 31 Substrate, 33, 34 Window member, 35 Support Tool, 36a, 37a Opening part, 38a, 39a Support tool, 41 Convex part, 42 Concave part, 45 Support tool, 46 Convex part, 47 Upper lid stopper, 51 Light absorbing film, 52 Film, 71 Concave part, 71a Bend part, 71b Bent part, 71c transmission part, 72 reflection transmission part.

Claims (9)

Out of a water tank having a reflection / transmission part in which the amount of reflection and transmission of light changes depending on the presence or absence of liquid, light is received through the reflection / transmission part and light emitting means for emitting light toward the reflection / transmission part. A water level detection means comprising a light receiving means for generating and outputting a corresponding signal;
A support device that supports the water level detection means, and includes optical paths that guide light from the light emitting means and light input to the light receiving means, respectively.
Water level determination means for determining the water level of water stored in a water tank based on a signal from the water level detection means ,
The support is formed with openings at positions facing the light emitting means and the light receiving means,
The water level detector according to claim 1, wherein the opening of the support has a truncated cone shape with a diameter decreasing toward the water tank . The water level detection device according to claim 1, wherein a light absorbing member is disposed on an inner wall of the opening. The water level detection device according to claim 1 or 2 , wherein a window member that is provided so as to face the light emitting means and the light receiving means and transmits light is provided in a housing for attaching the support. . The water level detection device according to claim 3, wherein a light absorbing member is disposed around the window member. 1st positioning means formed in the housing | casing, and 2nd positioning means formed in the said support tool, The said 1st positioning means and the said 2nd positioning means are engaged, and a housing | casing The water level detection device according to claim 1 , wherein the support is positioned with respect to the water level detection device. The water level detection device according to claim 1 , wherein the water level detection means is attached to a substrate. The light emitting means emits infrared light,
5. The water level detection according to claim 3 , wherein the window member is a member having a large transmittance of the infrared light in comparison with the transmittance of the infrared light and the transmittance of visible light. apparatus. A cooking device comprising the water level detection device according to any one of claims 1 to 7 . A body containing a rice cooker;
A lid that covers the main body so as to be freely opened and closed;
A water tank that includes a reflection / transmission part in which the amount of reflection and transmission of light changes depending on the presence or absence of liquid, and is detachably attached to the main body;
Steam introducing means for condensing the steam generated on the main body side to the water tank;
A water level detection device according to claim 3, 4 or 7 ,
Forming a convex on the side of the main body, forming a lid stopper for closing the lid on the upper surface of the convex;
Storing at least the water level detecting means in the convex portion, and arranging the window member on a side portion of the convex portion;
A heating cooker characterized in that a recess functioning as the reflection / transmission part is formed in the water tank.

Images