JP2008113615A - Heating control apparatus of ornamental aquarium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water level sensor that is free from risks of causing deterioration of functions of detecting the water level caused by adhesion of an algae, corrosion or the like. <P>SOLUTION: The apparatus is equipped with a temperature-detecting part having incorporated therein a first and a second thermosensitive elements changing its electrical resistance value according to the temperature, a first temperature-detecting circuit 51 for taking out output according to the electrical resistance value of the first thermosensitive element, a second temperature-detecting circuit 52 for taking out output according to the electrical resistance value of the second thermosensitive element, a control part 6 for judging whether the temperature-detecting part is in water or not by the comparison between the output of the first temperature-detecting circuit 51 and the output of the second temperature-detecting circuit 52, and a display 7 for outputting the result of the judgment by the control part 6. In the second temperature-detecting circuit 52, a circuit is provided for energizing the second thermosensitive element so that the generated temperature of the second thermosensitive element in the air reaches a temperature higher than the outer atmosphere temperature. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a water level sensor used to detect the level of liquid such as water filled in an aquarium, tank, container, etc., and to monitor whether the water level is appropriate, and in particular, for ornamental fish and aquatic plants. It is related with the water level sensor suitable for monitoring whether the water level with which the water tank with which etc. are accommodated is appropriate, and whether the water temperature sensor is correctly installed in water.

  Furthermore, the present invention relates to a heating control device with a water level sensor used for heating a liquid such as water filled in an aquarium, a tank, a container, etc., and in particular, in an aquarium in which ornamental fish or aquatic plants are accommodated. The present invention relates to a heating control device with a water level sensor that is used to heat filled water and maintain a set temperature.

  Conventionally, a typical heating control device used for an aquarium that houses ornamental fish, etc. is set with a heater installed in the aquarium, a water temperature sensor that is immersed in the water in the aquarium to detect the water temperature, and the water temperature In order to maintain a value (for example, 26 ° C.), a controller for controlling the energization of the heater so that the difference between the detected value of the water temperature by the water temperature sensor and the set value is zero.

  By the way, the water in this kind of aquarium is regularly exchanged, and at the time of exchanging water, it is sometimes inadvertently forgotten to install the water temperature sensor once taken out of the aquarium in the aquarium. When the heater is turned on while the water temperature sensor is left in the outside air, the water temperature sensor detects the outside air temperature. Therefore, especially in the winter when the outside air temperature is low, the detected value by the water temperature sensor is the set value of the water temperature (for example, 26 ° C.). As a result, energization of the heater is continued, which causes a problem that the water temperature rises significantly and kills ornamental fish and aquatic plants.

  In addition, the water temperature sensor may escape from the tank due to improper installation, etc.Furthermore, the water level in the tank drops for some reason, or water spills due to damage or falls of the water tank. The sensor may be exposed on the water surface and exposed to the outside air. In either case, the same trouble as described above due to abnormal heating occurs.

  In order to solve the above-mentioned problems, the water level sensor is used to monitor whether or not the water temperature sensor is exposed to the outside air. Recently, the water temperature sensor and the water level sensor are integrated. Is installed in the water tank, and when the water level sensor detects an abnormality in the installation of the water temperature sensor or an abnormality in the water level in the water tank, the power supply to the heater is stopped (for example, Patent Document 1). reference).

Japanese Patent Laid-Open No. 9-51740

  However, since the water level sensor described in Patent Document 1 is for immersing a pair of electrodes in water and detecting the above-described abnormality by the capacitance distributed between these electrodes and the ground electrode, If the algae adheres or the electrode is corroded, the water level detection function may be impaired, and there is a problem that it is impossible to reliably detect abnormalities such as abnormal installation of the water temperature sensor or water level in the water tank.

  This invention has been made paying attention to the above problems, and there is no possibility of causing a decrease in the water level detection function due to adhesion or corrosion of algae, an abnormal installation of the water temperature sensor, the water level in the aquarium, etc. It is an object of the present invention to provide a heating control device that can reliably detect an abnormality in the heater and stop energization of the heater.

  The water level sensor according to the present invention takes out a temperature measuring unit in which first and second temperature sensing elements whose electric resistance values change according to temperature and an output corresponding to the electric resistance value of the first temperature sensing element. A first temperature detection circuit, a second temperature detection circuit for extracting an output corresponding to the electric resistance value of the second temperature sensing element, an output of the first temperature detection circuit, and an output of the second temperature detection circuit; And a water level discriminating unit that discriminates whether or not the temperature detecting unit is in the liquid, and an output unit that outputs a discrimination result by the water level discriminating unit. The second temperature detection circuit is provided with a circuit for energizing the second temperature sensing element so that the heat generation temperature in the air of the second temperature sensing element reaches a temperature higher than the outside air temperature.

In the water level sensor having the above-described configuration, when the temperature detection unit is in the liquid, the second temperature sensing element is cooled by the liquid even if it generates heat, so the output of the first temperature detection circuit and the second temperature detection circuit Matches or nearly matches the output. Thereby, the water level discriminating unit discriminates that the temperature detecting unit is in the liquid.
On the other hand, when the temperature detecting unit is exposed to the outside air, the second temperature sensing element generates a heat generation temperature higher than the outside air temperature due to heat generation. This does not match the output of the temperature detection circuit. Thereby, the water level discriminating unit discriminates that the temperature detecting unit is not in the liquid, and the discrimination result is outputted from the output unit.

In the above-described configuration of the present invention, for example, a thermistor is suitable as the “first temperature sensing element” and the “second temperature sensing element”, but a resistor whose electric resistance value changes according to temperature, that is, The resistor is not limited to the thermistor as long as the resistance increases or decreases as the temperature increases.
The “output unit” converts the determination result into visible information or audible information and outputs the information, and includes a lamp, a display, a speaker, and the like.
Furthermore, each component such as a “water level determination unit” and a “liquid temperature determination unit” and a “heater control unit” to be described later can be realized by dedicated hardware, and can also be realized by a programmed computer.

The water level sensor of a preferred embodiment further includes a controller electrically connected to the temperature detection unit via a cord, and the controller includes a first temperature detection circuit, a second temperature detection circuit, a water level determination unit, and An output part is incorporated.
In this embodiment, only the temperature measuring part is immersed in the liquid. Note that the temperature measuring unit and the controller are not necessarily configured separately.

The water level sensor according to a preferred embodiment further includes a liquid temperature determination unit that determines the liquid temperature based on the output of the first temperature detection circuit, and a display that displays the determination result of the liquid temperature determination unit. .
The water level sensor according to this embodiment can be used as a water temperature sensor. If the temperature detecting unit is not in the liquid, the fact is output to the output unit, so that the liquid temperature is not correctly measured.
The display can also serve as the above-described output unit. In this case, when it is determined that the temperature measuring unit is not in the liquid, for example, an error is displayed on the display, and the temperature measuring unit is in the liquid. When it is determined, the liquid temperature is displayed on the display.

The heating control device according to the present invention comprises a heater installed in a tank filled with a liquid and a control device for controlling energization of the heater.
The control device includes a temperature detector in which first and second temperature sensing elements whose electrical resistance changes according to temperature, and a first output for taking out an output corresponding to the electrical resistance value of the first temperature sensing element. A temperature detection circuit; a second temperature detection circuit that extracts an output corresponding to the electric resistance value of the second temperature sensing element; a liquid temperature determination unit that determines the liquid temperature based on the output of the first temperature detection circuit; Comparison between the heater control unit for controlling energization of the heater so that the liquid temperature becomes a set value according to the determination result by the temperature determination unit, and the output of the first temperature detection circuit and the output of the second temperature detection circuit And a water level discriminating unit that discriminates whether or not the temperature detecting unit is in a liquid, and the second temperature detecting circuit has a temperature generated by the second temperature sensing element in the air higher than the outside air temperature. A circuit for energizing the second temperature sensing element is provided so as to reach a high temperature. The heater control unit stops energization of the heater when the water level determination unit determines that the temperature detection unit is not in the liquid.

In the heating control device having the above-described configuration, when the temperature detection unit is in the liquid, the second temperature sensing element is cooled by the liquid even if it generates heat, so the output of the first temperature detection circuit and the second temperature detection It matches or nearly matches the output of the circuit. Thereby, the water level discriminating unit discriminates that the temperature detecting unit is in the liquid. On the other hand, the liquid temperature determination unit determines the liquid temperature based on the output of the first temperature detection circuit. The heater control unit receives the determination result by the water level determination unit that the temperature detection unit is in the liquid, and controls the energization of the heater so that the liquid temperature becomes a set value according to the determination result by the liquid temperature determination unit.
On the other hand, when the temperature detecting unit is exposed to the outside air, the second temperature sensing element generates a heat generation temperature higher than the outside air temperature due to heat generation. This does not match the output of the temperature detection circuit. Thereby, the water level discriminating unit discriminates that the temperature detecting unit is not in the liquid. The heater control unit stops energization of the heater in response to the determination result by the water level determination unit that the temperature detection unit is not in the liquid.

  According to the present invention, for example, when the water level sensor is installed in a water tank that accommodates ornamental fish or aquatic plants, even if algae adheres to the temperature measuring section, the water level detection function is not impaired. In addition, it is possible to reliably detect abnormalities such as water temperature sensor installation and water level in the aquarium, and to stop energizing the heater, preventing abnormal heating of water and causing the trouble of killing ornamental fish and aquatic plants. There is no risk of inviting.

FIG. 1 shows a use state of a heating control device for an aquarium for aquarium fish or the like according to an embodiment of the present invention.
The heating control device in the illustrated example includes a heater 1 and a control device 2, and the heater 1 is installed on the bottom inside the water tank 10. The aquarium 10 is filled with water and contains ornamental fish and aquatic plants.

  The heater 1 is one in which an electric heating member such as a nichrome wire is loaded inside the tube 11 and magnesia powder is filled in order to increase thermal conductivity. Both ends of the tube 11 are closed with rubber caps 12 and 12, and a cord wire 14 with a connector 13 attached to the tip is drawn out from one rubber cap 12.

  As shown in FIGS. 1 and 2, the control device 2 includes a temperature detector 3 and a controller 4. The temperature detector 3 and the controller 4 are connected by a cord 30. A connection cord 40 and a power cord 41 are drawn from the controller 4. A socket 42 to which the connector 13 is connected is attached to the tip of the connection cord 40, and a power plug 43 to be inserted into a 100 volt power outlet is attached to the tip of the power cord 41.

The temperature measuring unit 3 has a bifurcated shape having two finger-like portions 31 and 32. As shown in FIG. 3, the longer temperature of the finger-like portion 31 includes the first temperature sensing element 5 on the shorter side. The second temperature sensing element 50 is incorporated in each finger portion 32. The entire temperature measuring unit 3 is molded with rubber 33, thereby ensuring waterproofness and insulation.
As the first and second temperature sensitive elements 5 and 50, thermistors having the same characteristics are used. The thermistor is a negative resistance element, that is, a resistance element having a negative temperature coefficient, and the electrical resistance value decreases as the temperature rises. Instead of the thermistor, a resistive element such as a positive temperature coefficient thermistor having a positive temperature coefficient, that is, an element whose electrical resistance value increases as the temperature rises may be used. In the figure, reference numerals 34 and 35 denote lead wires, which are bundled into one cord wire 30 and led to the controller 4.

  The temperature measuring unit 3 is attached to the inner wall surface of the water tank 10 using an appropriate holder. Various holders such as those provided with a suction cup can be used. When the water level in the water tank 10 falls below the installation position of the temperature detection unit 3, the temperature measurement unit 3 is exposed to the outside air, so that the control unit 6 described later determines this and notifies that effect or supplies power to the heater 1 Or stop.

  The controller 4 has a circuit configuration for maintaining the water temperature at a set temperature by controlling on / off of energization to the heater 1 based on the temperature sensing operation of the first and second temperature sensing elements 5, 50. A circuit configuration for stopping energization of the heater 1 when the temperature detecting unit 3 is not in the water but exposed to the outside air is incorporated.

FIG. 4 shows a circuit configuration incorporated in the controller 4. A first temperature detection circuit 51, a second temperature detection circuit 52, a display 7, and a heater are connected to a control unit 6 composed of a microcomputer via a bus 63. A lamp 70, a power lamp 71, a semiconductor switch 8, and the like are connected.
The control unit 6 includes a CPU 60 that is the main body of control and calculation, a ROM 61 that stores programs and fixed data, and a RAM 62 that is used for reading and writing data. It functions as a water level discriminating unit that discriminates whether or not there is a heater, and a heater control unit that controls energization of the heater 1.

The first temperature detection circuit 51 is for taking out an output corresponding to the electric resistance value of the first temperature sensing element 5, and is constituted by, for example, a bridge circuit 53 as shown in FIG. The bridge circuit 53 shown in the figure includes one variable resistor VR and two fixed resistors R1 and R2 constituting a reference resistor. A voltage output V _P (= V2−V1) is obtained between the output terminals 54 and 55, and this voltage output V _P is read into the CPU 60.

The second temperature detection circuit 52 is for taking out an output corresponding to the electric resistance value of the second temperature sensing element 50, and is constituted by, for example, a series resistance circuit 56 as shown in FIG. The series resistance circuit 56 in FIG. 6 is a circuit in which a second temperature sensing element 5 and a resistor R3 are connected in series, and the heat generation temperature in the air of the second temperature sensing element 5 is higher than the outside air temperature (for example, The current I flowing through the second temperature sensing element 5 is determined so as to reach 60 ° C.). The value of the current I can be adjusted by appropriately selecting the size of the resistor R3. A voltage output V _Q is obtained at the output terminal 57, and this voltage output V _Q is read by the CPU 60.

The display 7, the power lamp 71, and the heater lamp 70 are provided on the surface of the controller 4 as shown in FIG.
The indicator 7 is composed of a three-digit digital indicator. When it is determined that the temperature detector 3 is in water, the temperature is displayed as a number, and when it is determined that the temperature detector 3 is not in water. An error is displayed (for example, EEE characters are displayed).
The power lamp 71 and the heater lamp 70 are made of LEDs. The power lamp 71 is lit when the power plug 43 is inserted into a power outlet, and the heater lamp 70 is lit when the heater 1 is energized.
The controller 4 is provided with a temperature setting dial 72 for variably setting the variable resistor VR. By operating the temperature setting dial 72, the water temperature can be adjusted to an arbitrary set temperature.

The semiconductor switch 8 is interposed in an energization circuit to the heater 1, and is constituted by, for example, a triac.
CPU60 of the control unit 6, the voltage output V _P of the first temperature detecting circuit 51 to determine the temperature, on the semiconductor switch 8 so the water temperature reaches the set value according to the determination result, to off control.
Further, the CPU 60 of the control unit 6 obtains a difference (V _P −V _Q ) between the voltage output V _{P of} the first temperature detection circuit 51 and the voltage output V _{Q of} the second temperature detection circuit 52, and the value is If it is not zero or a value close to zero, it is determined that the temperature detecting unit 3 is not in water but is exposed to the outside air, and the semiconductor switch 8 is turned off to stop energization of the heater 1.

Next, the operation of the above embodiment will be described.
First, the heater 1 is installed on the bottom inside the water tank 10, the temperature detecting unit 3 is held by a holder (not shown) and installed on the side wall surface of the water tank 10, and then the power plug 43 is inserted into a power outlet. When the heater 1 is energized under the control of the controller 4, the heater 1 generates heat and the water in the water tank 10 is heated.

The first temperature sensing element 5 incorporated in the temperature measuring unit 3 has an electrical resistance value that decreases as the temperature of the water in the water tank 10 rises, but when the temperature of the water in the water tank 10 is equal to or lower than the set temperature, since the voltage output V _P of the first temperature detection circuit 51 is the reference voltage greater than or equal _to V _0, semiconductor switch 8 is turned on, the energization of the heater 1 is held.
If the temperature of the water in the water tank 10 is larger than the set temperature, the voltage output V _P of the first temperature detection circuit 51 is smaller than the reference voltage V _0, semiconductor switch 8 is turned off, the energization of the heater 1 Stopped.
CPU60 of the control unit 6 discriminates the water temperature by the voltage output V _P of the first temperature detection circuit 51, and displays the water temperature on the display 7.

The second temperature sensing element 50 is supplied with a current I having a magnitude such that the heat generation temperature in the air reaches a temperature higher than the outside air temperature (for example, 60 ° C.), but when the temperature measuring unit 3 is in water, Even if the second temperature sensing element 50 generates heat, it is cooled by water, so that the electrical resistance value decreases as the temperature of the water in the water tank 10 increases as in the first temperature sensing element 5, and as a result, and the voltage output V _P of the first temperature detection circuit 51 and the voltage output V _Q of the second temperature detecting circuit 52 coincides or substantially coincides. Thereby, CPU60 of the control part 6 can discriminate | determine that the temperature detection part 3 exists in water.

On the other hand, when the temperature detecting unit 3 is exposed to the outside air, the second temperature sensing element 50 reaches a temperature higher than the outside air temperature due to heat generation. It does not coincide with the output V _P and the voltage output V _Q of the second temperature detection circuit 52. Thereby, CPU60 of the control part 6 can discriminate | determine that the temperature detection part 3 is not in water but is exposed to the open air.

FIG. 7 shows a flow of control by the CPU 60 of the control unit 6. In the figure, “ST” is an abbreviation for “STEP” (procedure).
In ST1 of FIG, CPU 60 is after reading the voltage output _{V Q} of the voltage output _{V P} and the second temperature detection circuit 52 of the first temperature detection circuit 51, the voltage output _{V P} and the voltage output _{V Q} The difference voltage V is calculated (ST2).

In the next ST3, the CPU 60 determines whether or not the voltage V is zero or a value close to zero. If it is determined in ST3 is "YES", the temperature measuring unit 3 is judged to be in the water, the process proceeds from ST3 to ST9, CPU 60, the voltage output _{V P} of the first temperature detection circuit 51 is the reference voltage _{V 0} To determine whether or not. If the water temperature does not reach the set temperature, the voltage output _VP is larger than the reference voltage V _0, so that the determination of ST9 is “NO”, the determination of ST10 is “YES”, and the CPU 60 is the heater 1 Is set to the on state (ST11).

Thus, the water temperature by electrical heating of the heater 1 exceeds the set temperature, it becomes a smaller value than the voltage output _{V P} is the reference voltage _{V 0,} "NO" is determined in ST9, the determination of ST10 is "NO", CPU 60 Sets the heater 1 to the OFF state (ST12).
Incidentally, when the water temperature is equal to the set temperature, because the voltage output V _P and the reference voltage V ₀ matches, the decision is "YES" in ST9, the heater 1 is turned on or off state is maintained.

  When the CPU 60 determines that the voltage V is zero or a value close to zero in ST3, it is determined that the temperature detecting unit 3 is not in water but is exposed to the outside air, and the process proceeds from ST3 to ST4. The heater 1 is de-energized and an error is displayed on the temperature display 7.

Subsequently, CPU 60 reads the voltage output _{V Q} of the voltage output _{V P} and the second temperature detection circuit 52 of the first temperature detection circuit 51 (ST5), the difference between the voltage output _{V P} and the voltage output _{V Q} The voltage V is calculated (ST6), and it is determined whether the voltage V is zero or a value close to zero (ST7), and the temperature detecting unit 3 is immersed in water from the state exposed to the outside air The procedure of ST5, 6, and 7 is repeated until it transfers to.

  When the temperature measuring unit 3 is immersed in water, the voltage V becomes zero or a value close to zero. Therefore, the determination in ST7 is “YES” and the process proceeds to ST8, and the error display on the display unit 7 is canceled. Shift to temperature control after ST9.

  In addition, the heating control apparatus of the said Example monitors in the aquarium 10 while monitoring whether the temperature detection part 3 is correctly installed in the water with which the aquarium 10 in which ornamental fish, aquatic plants, etc. are accommodated is accommodated. The filled water is heated and kept at the set temperature. However, the present invention is not limited to this, and water filled in a tank, a tank, a container, or the like other than the aquarium 10 for ornamental fish, and further water. Water level sensor that detects the water level of other liquids and monitors whether the water level is appropriate, and water such as water filled in tanks, tanks, containers, etc. other than aquarium 10 for aquarium fish etc. Thus, it can be implemented in a heating control device that maintains the set temperature.

It is a perspective view which shows the use condition of the heating control apparatus of the water tank which is one Example of this invention. It is a front view which shows the structure of a control apparatus. It is sectional drawing which shows the internal structure of a temperature measurement part. It is a block diagram which shows the circuit structure integrated in a controller. It is an electric circuit diagram which shows a 1st temperature detection circuit. It is an electric circuit diagram which shows a 2nd temperature detection circuit. It is a flowchart which shows the flow of control by a control part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heater 2 Heating control apparatus 3 Temperature detection part 4 Controller 5 1st temperature sensing element 50 2nd temperature sensing element 51 1st temperature detection circuit 52 2nd temperature detection circuit 6 Control part 60 CPU
61 ROM
62 RAM
7 Water temperature indicator

Claims (4)

  A temperature detecting unit in which first and second temperature sensing elements whose electric resistance values change according to temperature are incorporated, and a first temperature detection circuit for extracting an output corresponding to the electric resistance value of the first temperature sensing element; The temperature detecting unit compares the output of the second temperature detecting circuit and the output of the first temperature detecting circuit with the output of the second temperature detecting circuit. A water level discriminating unit that discriminates whether or not the liquid is in a liquid; and an output unit that outputs a discrimination result by the water level discriminating unit. The second temperature detection circuit includes a second temperature sensing element in the air. A water level sensor provided with a circuit for energizing the second temperature sensing element so that the heat generation temperature reaches a temperature higher than the outside air temperature.   The water level sensor according to claim 1, further comprising a controller electrically connected to the temperature detection unit via a cord, the controller including a first temperature detection circuit, a second temperature detection circuit, A water level sensor that includes a water level discriminating unit and an output unit.   The water level sensor according to claim 1 or 2, further comprising: a liquid temperature determination unit that determines a liquid temperature based on an output of the first temperature detection circuit; and a display that displays a determination result by the liquid temperature determination unit. Water level sensor provided. A heating control device comprising a heater installed in a tank filled with a liquid and a control device for controlling energization of the heater,
The control device includes a temperature detection unit in which first and second temperature sensing elements whose electric resistance values change according to temperature, and a first output that extracts an output corresponding to the electric resistance value of the first temperature sensing element. A temperature detection circuit, a second temperature detection circuit for taking out an output corresponding to the electric resistance value of the second temperature sensing element, a liquid temperature determination unit for determining the liquid temperature based on the output of the first temperature detection circuit, A heater control unit that controls energization of the heater so that the liquid temperature becomes a set value according to a determination result by the liquid temperature determination unit, an output of the first temperature detection circuit, and an output of the second temperature detection circuit A water level discriminating unit that discriminates whether or not the temperature detecting unit is in liquid by comparison, and the second temperature detecting circuit has a heat generation temperature in the air of the second temperature sensing element higher than the outside air temperature. A circuit is provided to energize the second temperature sensing element to reach the temperature,
The heater control unit is a heating control device configured to stop energization of the heater when the water level determination unit determines that the temperature detection unit is not in the liquid.

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