JPH0445654Y2 - - Google Patents

Description

[Detailed explanation of the invention] (Field of industrial application) This invention uses a magnet, a reed switch that responds to the magnet, and a float that moves up and down according to the liquid level. The present invention relates to a liquid level detection device for a liquid container that detects the level of a liquid contained therein based on changes in the level of the liquid contained therein.

(Prior Art) This type of liquid level detection device is disclosed in Japanese Utility Model Application Publication No. 10149/1983.

In this device, a float is installed in a passage pipe connected to the container so as to maintain the same liquid level, and a reed switch and a magnet face each other through the passage pipe at a height position corresponding to the liquid level to be detected. It is set up to suit.

As a result, when the content liquid reaches the detection liquid level, the float is positioned between the reed switch and the magnet to cut off the mutual magnetic action, and if the content liquid exceeds or falls below the detection liquid level, the float is positioned between the reed switch and the magnet. Since the cutoff is released, it is possible to detect whether the liquid level is at the detection liquid level.

The float has a cylindrical surface and is placed inside the passage pipe.

(Problem to be solved by the invention) In the conventional example described above, the reed switch and the magnet must face each other across the passage pipe and react with each other, and the magnetic effect is proportional to the square of the distance between them. In some cases, the reed switch does not respond well to magnets, making accurate detection difficult.

A possible solution to this problem is to use strong magnets, but they are expensive and may affect other devices.

In addition, since the float faces the inner peripheral surface of the passage pipe with its cylindrical surface, if the play between them is small, it would move up and down within the passage pipe, but it would be difficult to move due to the influence of the surface tension of the liquid inside. , it is difficult to respond accurately to fluctuations in liquid level. Moreover, it is not suitable for detecting the liquid level in a pipe line through which the liquid content must pass.

In addition, if there is a lot of play, the position of the float within the passage pipe will not be stable, and the float may become slanted and become twisted within the passage pipe, causing it to become unable to move, making it difficult to stably detect the level of the liquid content. I can't. When detecting the liquid level in a passage pipe through which the liquid content must pass, the float in particular is exposed to the liquid flow and its posture changes in a complex manner, and the condition and flow rate of the liquid flow passing through it fluctuates. This is a problem if the flow path is for dispensing water, and the float is susceptible to clogging due to frequent changes in posture, which is a practical problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid level detection device for a liquid container that does not have the problems described above by improving the float and the system in which the float and reed switch face each other.

(Means for Solving the Problems) In order to achieve the above-mentioned problems, the present invention incorporates a magnet placed inside a tube installed in a container to maintain the same liquid level as the liquid level inside the container. It is equipped with a float and a reed switch that faces the float at a specific position outside the tube and detects a specific liquid level by reacting to the magnet of the float. This device is characterized by having guide ribs facing each other to form a liquid passage between the outer circumferential surface of the float and the inner circumferential surface of the tube, and to define the distance between the magnet in the float and the reed switch.

(Function) The liquid inside the container is maintained at the same level as the liquid level inside the container by a magnet built into a float placed inside a tube installed in the container, and a magnet installed outside the tube. The magnet and the reed switch, which faces the float at a specific position and reacts to the magnet to detect a specific liquid level, have an opposing structure in which they face each other through the float and the peripheral wall of the tube, so the spacing between them is the same as the conventional one. The reed switch is much smaller than the previous case, and the reed switch is easily responsive to the magnet and can properly detect the liquid level.

In addition, when the float moves up and down inside the tube, the plurality of guide ribs along the length of the tube on the outer periphery of the float guide the float by contacting the inner circumferential surface of the tube with little play and a small contact surface, so that the float can be kept almost constant. It is possible to move up and down smoothly and stably while maintaining the position of the float, with little movement resistance due to the influence of the surface tension of the liquid content, etc. It also prevents clogging due to twisting, fluctuations in the float's position relative to the liquid level, and fluctuations in posture. It is possible to stably detect an appropriate liquid level without any problems.

Furthermore, since the guide ribs form a liquid passage between the outer circumferential surface of the float and the inner circumferential surface of the tube, stable and appropriate liquid level detection as described above is possible even in the tube through which the liquid content passes; Since the distance between the magnet built into the float and the reed switch is kept constant, errors in liquid level detection due to fluctuations in this distance can be avoided, and the accuracy of liquid level detection is greatly improved.

(Embodiment) The embodiment of the present invention shown in FIGS. 1 to 6 shows the case of an air pump type tabletop electric hot water storage container.

In this embodiment, as shown in FIG. 1, an inner container 2 with a heater 1 attached to its bottom is housed and held in an exterior body 3 to form a container body 4. The upper end of the inner container 2 is connected to the upper end of the exterior body 3 by a shoulder member 5.
An outer cover 7 is pivotally attached to the rear part of the cover by a shaft 6 so as to be openable/closeable and detachable. The inner container 2 is located on the bottom surface of the outer lid 7.
An inner lid 8 is attached to close the mouth of the container, and is opened and closed integrally with the outer lid 7.

A bellows pump 10 is provided inside the outer lid 7 and is pressed and operated by the upper pressing plate 9 of the outer lid 7.
Pressurized air is fed into the inner container 2 through an air supply passage 12 provided between the inner lid 8 and the bellows pump bottom plate 11 to pressurize the content liquid. The air supply passage 12 is provided with a check valve 21 and a steam vent passage 14 that exits to the upper surface of the outer cover 7 through the branch hole 13.

The branch hole 13 is switched and closed to the air supply port 23 of the bellows pump bottom plate 11 by a valve 22 that is moved down in conjunction with the pressing operation of the bellows pump 10, and pressurized air is released into steam when the content liquid is pressurized. Extraction passage 13
This prevents steam from escaping to the bellows pump 10 or from entering the bellows pump 10 when hot water is stored.

A lead-out passage 17 for guiding the pressurized content liquid upward to the outside of the inner container 2 is provided with its base end connected to the bottom of the inner container 2, and a lateral passageway 17 connected to the bottom of the inner container 2 at its upper and lower ends to be attached to a bypass pipe 29 described later. Pipes 15 and 16 are connected. This horizontal pipe 15 is connected to an inverted U-shaped pipe 18 fixed to the back side of the beak-like portion 5a of the shoulder member 5. The inverted U-shaped pipe 18 has a built-in water stop valve 19 in the event of a fall, and a downward discharge port 2 at the tip.
0 has a slit 24 formed therein. A pipe cover 25 is assembled under the beak-shaped portion 5a of the vessel body 4, and is fitted onto the beak-shaped portion 5a and the exterior body 3 of the vessel body 4. A liquid injection guide tube 26 is detachably attached to the bottom of the pipe cover 25 from below.

The rising portion of the outlet path 17 is a liquid volume display portion made of a transparent tube 17b, which can be seen through a transparent window 28 provided in a resin panel 27 fitted to the front portion of the exterior body 3. Further, a bypass pipe 29 made of a magnetic material is attached to the side of the transparent pipe 17b portion of the lead-out path 17 via horizontal pipes 15 and 16. As shown in FIG. 2, at the bottom of the resin panel 27, there are provided a re-boiling switch operation button 30 and a heat retention selection switch operation button 31, which allow the heater 1 to boil the liquid at the appropriate time. A liquid temperature display section 32 for displaying the temperature of the content liquid, such as the state, is provided using a light emitting diode. The parts where these are provided are covered flush with a transparent resin cover sheet, and the necessary indications are printed on the back side of the cover sheet. The cover sheet is the transparent window 28 of the panel 27
It can also be extended to the opening of the window and covered flush with it, and can be used in place of the transparent window plate 33.

The bypass pipe 29 consists of a pipe 29a and a relay pipe 29b, both of which are connected by a packing 38. As shown in cross section in FIG. 4, the relay pipe 29b has a vertical rib 29b ₁ on its inner periphery. As shown in FIG. 3, a float 35 having a magnet 34 is placed inside the pipe 29a.

On the other hand, a reed switch 3 is installed on the outer periphery of the pipe 29a.
7 is attached using some kind of attachment means. A lead wire 39 is connected to a control circuit as shown in FIG.

The float 35 is prevented from floating upward by a vertical rib _29b1 of the relay pipe 29b. Therefore, the content liquid flowing into the bypass pipe 29 (maintains the same liquid level as the liquid level in the inner container 2)
Even if the liquid level is higher than the liquid level shown in Fig. 3, the float 35
The built-in magnet 34 is always opposed to the switch portion 37a of the reed switch 37. Then, the liquid level decreases from there (in this embodiment, the liquid level that has decreased by a certain amount from the liquid level when the magnet 34 faces the switch part 37a until the reed switch 37 reacts to the magnet 34 as described above is the lowest). The float 35 moves downward as the liquid level increases. Note that as shown in cross section in FIG.
Since the float 35 is provided with the step 16a, the lower movement of the float 35 is stopped by the stepped portion 16a even if the liquid level suddenly decreases, and the lower part of the float 35 protrudes from the bypass pipe 29 and becomes difficult to float. is prevented.

The outer periphery of the float 35 has three or more guide ribs 36 provided at equal intervals in the circumferential direction.
The guide ribs 36 are formed to be inclined so as to have a slight play between them and the bypass pipe 29, and there are a total of eight guide ribs, four in each of the upper and lower stages.

According to the liquid level detection structure as described above, the magnet 34 is built into the float 35 placed in the bypass pipe 29, and the magnet 34 is installed outside the bypass pipe 29 to detect the lowest liquid level for preventing dry cooking. The magnet 34 and the reed switch 37 which react to the magnet 34 and detect the lowest liquid level face each other through the float 35 and the circumferential wall of the bypass pipe 29, so that the distance S between them is is much smaller than in the conventional case, and the reed switch 37
is easily responsive to the magnet 34 and can appropriately detect the liquid level.

In addition, the guide rib 3 provided on the outer periphery of the float 35
6, when the float 35 moves up and down in the bypass pipe 29, the float 35 is guided by contacting the inner circumferential surface of the bypass pipe 29 with little play and a small contact surface, so that the float 35 can be kept in a substantially constant posture. However, it can be moved up and down smoothly and stably with less movement resistance due to the influence of surface tension of the content liquid, and it also prevents clogging and float 35 due to twisting.
It is possible to stably detect an appropriate liquid level without any fluctuation in position or attitude with respect to the liquid level.

Furthermore, since the guide rib 36 forms a liquid passage P between the outer circumferential surface of the float 35 and the inner circumferential surface of the bypass pipe 29, the stable and appropriate liquid level detection described above is possible even in the pipe through which the content liquid passes. This is possible, and since the distance S between the magnet 34 built into the float 35 and the reed switch 37 is kept constant, it is possible to avoid errors in detecting the liquid level due to fluctuations in this distance S. Detection accuracy is greatly improved.

Thus, when the float 35 in the bypass pipe 29 falls below the liquid level corresponding to the position where the reed switch 37 is provided, the reed switch 37
The switch portion 37a can react and electrically detect the lowest liquid level. In addition, in conjunction with the detection, it is preferable to light up the water supply display section of the liquid temperature display section 32 or activate a buzzer, thereby preventing dangers associated with dry heating of the electric pot and maintaining safety. I can do it.

As shown in FIG. 6, in the control circuit for detecting the liquid level, the heater 1 is divided into a heat retention heater 1a and a water boiling heater 1b, and the water boiling heater 1b is equipped with a dry cooking prevention thermostat 50 that operates at an abnormal temperature, Reboiling switch 30a, boiling response switch 51 that detects steam temperature, reed switch 37 for preventing dry cooking, and relay contact 5 of relay 52
2a and 52b. Reference numerals 53 and 54 are pilot lamps that display the operating status of boiling water and keeping warm water.

In this embodiment, the reed switch 37 is normally closed, and is turned on when it faces the magnet 34. Therefore, when the liquid level is higher than the level opposite to the position where the reed switch 37 is provided, the magnet 34 in the float 35 always faces the reed switch 37 to keep it on, but when the liquid level is more constant than that A relay 5 detects the lowest liquid level when the amount drops and turns off the reed switch 37 based on the signal at that time to ensure energization of the water heater 1b.
2. The circuit of the reboil switch 30a is turned off to prevent overheating. Note that although electricity continues to be supplied to the heat-retaining heater 1a, this does not pose a safety problem.

The control circuit is installed on the circuit board 42. This circuit board 42 is integrally formed with a part of an annular bottom plate 44 attached to the lower end of the exterior body 3, and is housed from below in a control box 43 that opens downward and is screwed into the control box 43.

A rotating bottom plate 46 is attached to the end of the bottom plate 44. The rotating bottom plate 46 forms a ring body in which an annular outer wall 47 and an annular inner wall 45 are connected at their lower ends, and is movable between the bottom plate 44 and a locking ring 49 attached to the lower surface thereof via a support fitting 48. Possibly held. The support fitting 48 is attached to the bottom plate 44, and the locking ring 49 is attached to the support fitting 48, respectively.

The present invention can be configured in various ways other than those shown in the above embodiments. For example, although the reed switch 37 of this embodiment is turned on by facing the magnet 34, it may be turned off by facing the magnet 34. In that case, the reed switch 37
It is preferable to install the reed switch 37 so that the liquid level when facing the reed switch 4 is the lowest liquid level, and to provide a stopper to prevent the float 35 from moving below the liquid level and turning on. Note that the vertical rib _29b1 of this embodiment, which acts as a stopper for the float 35, can be adjusted by cutting the rib if the minimum liquid level differs depending on the capacity of the inner container 2, the way the outlet passage 17 is provided, etc. Also, depending on the depth of the inner container 2, by replacing the relay pipe 29b, it is possible to create units according to size.

(Effects of the invention) According to the invention, the content liquid in the container is maintained at the same level as the liquid level in the container by incorporating a magnet in a float placed in a tube provided in the container. ,
A reed switch that is provided outside the tube and faces the float at a specific position and reacts to the magnet to detect a specific liquid level and the magnet have an opposing structure in which they face each other through the float and the peripheral wall of the tube. Therefore, the distance between the two is much smaller than in the conventional case, and the reed switch easily responds to the magnet and can properly detect the liquid level.

In addition, the plurality of guide ribs along the length of the tube on the outer periphery of the float guide the float by contacting the inner peripheral surface of the tube with little play and a small contact surface when the float moves up and down inside the tube. While maintaining a constant posture, it can be moved up and down smoothly and stably with little movement resistance due to the influence of the surface tension of the liquid content, and it also prevents clogging due to twisting, fluctuations in the float's position relative to the liquid level, and fluctuations in posture. It is possible to stably detect an appropriate liquid level without any problems.

Furthermore, since the guide ribs form a liquid passage between the outer circumferential surface of the float and the inner circumferential surface of the tube, stable and appropriate liquid level detection as described above is possible even in the tube through which the liquid content passes; Since the distance between the magnet built into the float and the reed switch is kept constant, errors in liquid level detection due to fluctuations in this distance can be avoided, and the accuracy of liquid level detection is greatly improved.

In short, it is possible to provide a convenient liquid level detection device that has a simple structure, can be provided at low cost, has high accuracy, and can be used regardless of whether or not the content liquid is passing through.

[Brief explanation of the drawing]

1 to 6 show an embodiment of the present invention, FIG. 1 is a vertical side view thereof, FIG. 2 is a front view thereof, FIG. 3 is a vertical side view of main parts, and FIG. 4 is a third side view. A- in the diagram
A sectional view taken along line A', Figure 5 is a sectional view taken along line B-B' in Figure 3,
FIG. 6 is a control circuit diagram. 2... Inner container, 17... Outlet path, 29... Bypass pipe, 34... Magnet, 35... Float, 36
...Guide rib, 37...Reed switch, P...
...liquid passage, S... spacing.

Claims (1)

[Scope of utility model registration request] A float with a built-in magnet placed inside a tube installed in a container to maintain the same liquid level as the liquid level inside the container, and a magnet of this float placed outside the tube and facing the float at a specific position. A reed switch that detects a specific liquid level in response to A liquid level detection device for a liquid container, characterized in that a liquid passage is formed and a distance between a magnet in a float and a reed switch is defined.