JP3920836B2 - Water temperature control device for aquarium - Google Patents

Description

    The present invention relates to a water temperature control device that controls the temperature of a water tank for breeding ornamental fish and the like.

As a conventional water temperature control device for a water tank, for example, a device as described in Patent Document 1 below is known.
Japanese Patent Laid-Open No. 10-14439

  This is connected to a plug connected to an AC power source at the proximal end, and a pair of energized wires provided with a heating element that generates heat when the current is applied between the distal ends to raise the temperature of water in the water tank, A triac provided on the energization line that controls the energization state of the energization line based on the input gate current, a water temperature detection sensor that detects the water temperature in the aquarium, and a triac gate based on the detection result from the water temperature detection sensor And a control circuit capable of outputting current. As the above-described control circuit, a zero-cross pulse (a synchronization pulse is generated near the zero point of the AC voltage) drive circuit is usually used.

    However, in such a conventional water temperature control device for an aquarium, when a triac, control circuit, etc. breaks down and becomes uncontrollable in a state where power is continuously applied to the heating element, until a person notices it, No countermeasures can be taken, and as a result, there is a problem that the water temperature rises to an abnormal temperature and the aquarium fish may be killed.

  For this reason, the same triac, water temperature detection sensor, and control circuit as those described above are added to the conducting wire on the tip side of the TRIAC, and these added TRIACs, etc. It is also conceivable to control the energization state. However, when a triac or the like is simply added as described above, the gate current (pulse current) is input to the existing triac because the added triac or the like has a very large impedance value of about several tens of MΩ in the cut-off state. However, only a current of several μA, which is significantly lower than the holding current (several hundred mA or more) of the existing triac, flows through the conducting wire, and as a result, the existing triac does not operate and the water temperature cannot be controlled at all. .

  In order to solve such a situation, it is conceivable to connect a pair of energization lines between the existing triac and the additional triac with a connection line, and to provide a light start load in the middle of the connection line. In order for a current exceeding the holding current to flow through the triac, the impedance value of the light starting load must be smaller than about 200Ω. However, if the impedance value of the light start load is such a value, a large amount of heat is generated from the light start load. As a result, if forced cooling means such as a fan is not installed and forced cooling is performed, the triac or the like There is a problem in that the electronic component is heated to an allowable upper limit temperature or higher.

  An object of the present invention is to provide a water temperature control device for a water tank that does not require forced cooling and can safely control the water temperature even in the event of a failure.

    For this purpose, a plug connected to an AC power source is connected to the proximal end, and a pair of energized wires provided with a heating element that generates heat when the current is applied between the distal ends and raises the temperature of the water in the water tank. A base-end thyristor that is provided in the energization line and controls the energization state of the energization line based on an input gate current; and a gate current that is provided in the energization line on the distal end side of the base-end thyristor and is input A thyristor for controlling the energization state of the energization line based on the current, a base end side and a tip end detection sensor for detecting the water temperature, and a continuous direct current to the base end thyristor based on the detection results from the base end detection sensor. A proximal-side control unit that can output a gate current of the current, and a distal-side control unit that can output a gate current to the distal-side thyristor based on the detection result from the distal-side detection sensor When the gate current is output from the base end side control unit to the base end side thyristor, the base end is provided in the middle of the connection line connecting the pair of energization lines between the base end side thyristor and the tip end side thyristor. This can be achieved by providing a light start load with a small calorific value that keeps the side triac in a conductive state.

  In the present invention, a continuous DC current is output as a gate current from the proximal-side control unit to the proximal-side thyristor, and a connection line connecting a pair of energization lines between the proximal-side thyristor and the distal-side thyristor is provided. Since the light start load is provided, the base end side thyristor can be made conductive regardless of the holding current. As a result, by making the impedance value of the light start load larger than the light start load described in the background art, even if the amount of heat generated from the light start load when energized is reduced to a level that does not require forced cooling, the water temperature control The device can be operated normally.

  As a result, the conduction state of the proximal side and distal side thyristors is controlled by the gate current output from the proximal side and distal side control units based on the detection results from the proximal side and distal side detection sensors, and the water temperature is controlled. Control is performed. At this time, even if any of the thyristor, detection sensor, or control unit on the base end side or the tip end side fails and the thyristor on the base end side or the tip end side is in a conductive state and cannot be controlled, the remaining thyristors Since it operates normally, water temperature control can be performed safely.

Moreover, if comprised as described in Claim 2, a base end side thyristor can be operated reliably, suppressing heat_generation | fever effectively.
Further, according to the third aspect of the present invention, when either the proximal thyristor or the like or the distal thyristor or the like fails, it is possible to cope with the problem by simply replacing the failed thyristor or the like. Moreover, since the thyristor, the detection sensor, the control unit, and the heating element on the front end side are unitized as a heater unit and are commercially available, they can be used as they are.
According to the fourth aspect of the present invention, an inexpensive low-precision sensor can be used as the tip side detection sensor, and the tip side thyristor has a small number of switching operations, so that it is difficult to break down and the limiter is surely secured. Can function as.

Embodiment 1 of the present invention will be described below with reference to the drawings.
In FIGS. 1 and 2, reference numeral 11 denotes an aquarium for breeding ornamental fish. A predetermined amount of water (fresh water, seawater) W is stored in the aquarium 11. 12 and 13 are a pair of base-side conductive wires installed away from the water tank 11, and a plug 14 connected to a commercial AC power source is connected to the base ends of these base-side conductive wires 12 and 13, On the other hand, output sockets 15 as base end side connector pieces are connected to the tips of the base end side conductive wires 12 and 13.

  Reference numeral 16 denotes a case of the control unit 18 provided with a water temperature setting device 17 for setting the water temperature, and the middle of the base-side conductive wires 12 and 13 passes through the case 16. Reference numeral 19 denotes a triac, SCR, or other power control element built in the case 16, and here is a base end side thyristor composed of a triac. The base end side thyristor 19 is a part of the portion passing through the case 16. Provided in the base-side conductive line 12 or 13, here the base-side conductive line 12, controls the energization state in the base-side conductive lines 12, 13 based on a gate current described later.

  Reference numeral 21 denotes a detection unit that is submerged in the water W, and a case 22 of the detection unit 21 includes a thermistor and the like, and a base end side detection sensor 23 that detects the water temperature of the water W is incorporated therein. The base end side detection sensor 23 and the comparison circuit 24 built in the case 16 are connected by a connection line 25. The comparison circuit 24 has a gate current connected to the water temperature setter 17 and the base end side thyristor 19. Is connected to the gate circuit 27. Reference numeral 26 denotes a DC power supply circuit that generates a DC constant voltage.

  When the setting signal from the water temperature setter 17 and the detection signal from the base end side detection sensor 23 are input to the comparison circuit 24, the comparison circuit 24 detects the temperature detected by the base end side detection sensor 23 and the water temperature setter. When the detected temperature is lower than the set temperature, a gate current is output from the gate circuit 27 to the base side thyristor 19 to bring the base side thyristor 19 into a conductive state. On the other hand, when the detected temperature exceeds the set temperature, the output of the gate current is stopped and the base end side thyristor 19 is turned off. The water temperature setter 17, the comparison circuit 24, and the gate circuit 27 described above as a whole can output a gate current to the base end side thyristor 19 based on the detection result from the base end side detection sensor 23. 29, and the case 16, the base end side thyristor 19, the DC power supply circuit 26, and the base end side control unit 29 constitute the control unit 18 as a whole.

  31 is an auxiliary heater built in the case 22 of the detection unit 21, and this auxiliary heater 31 is installed in the vicinity of the base end side detection sensor 23. Since the auxiliary heater 31 is always energized with a small amount of power after the power is turned on, a small amount of heat is radiated from the auxiliary heater 31.

  Reference numerals 34 and 35 denote a pair of distal-side conductive wires, and the distal ends of the distal-side conductive wires 34 and 35 are coupled and separable at the base ends of the distal-side conductive wires 34 and 35, which are coupled when inserted into the output socket 15 and separated when pulled out. An input plug 36 is provided as a piece. On the other hand, a heating wire 37 serving as a heating element that generates a large amount of heat when energized and raises the temperature of the water W in the water tank 11 is provided between its tips. ing. The distal end portions (including the heating wire 37) of the distal end side conductive wires 34 and 35 are hermetically housed in the case 39 of the heater unit 38 submerged in the water W of the water tank 11.

  The case 39 contains a water temperature setter 40 that can adjust the set temperature from the outside. The set temperature of the water temperature setter 40 is higher than the set temperature of the water temperature setter 17 (target temperature suitable for breeding). When the set temperature of the water temperature setter 17 is slightly high, for example, 26 degrees C, the set temperature of the water temperature setter 40 is set to about 36 degrees C. 41 is a triac, SCR, etc. housed in a case 39, and here is a front end thyristor composed of a triac. The front end side thyristor 41 is a front end side conducting wire 34 or a portion located in the case 39. 35, here, provided on the front end side conductive wire 34, and controls the energization state in the front end side conductive wires 34, 35 based on a gate current described later.

  Reference numeral 44 denotes a tip side detection sensor housed in the case 39 and configured by a thermistor or the like. The tip side detection sensor 44 is disposed in close contact with the inner surface of the case 39 and detects the water temperature of the water W through the case 39. . 45 is a comparison circuit built in the case 39 and connected to the water temperature setter 40 and the tip side detection sensor 44. The comparison circuit 45 is connected to a gate circuit 47 that outputs a gate current to the tip side thyristor 41. Has been. Reference numeral 46 denotes a DC power supply circuit that generates a DC constant voltage.

  Then, when the setting signal from the water temperature setting device 40 and the detection signal from the front end side detection sensor 44 are input to the comparison circuit 45, the comparison circuit 45 uses the temperature detected by the front end side detection sensor 44 and the water temperature setting device 40. When the detected temperature is lower than the set temperature, the gate current is output from the gate circuit 47 to the tip side thyristor 41 to make the tip side thyristor 41 conductive, while detecting the detected temperature. When the temperature exceeds the set temperature, the output of the gate current is stopped and the tip side thyristor 41 is turned off.

  The water temperature setter 40, the comparison circuit 45, and the gate circuit 47 described above constitute a tip side control unit 48 that can output a gate current to the tip side thyristor 41 based on the detection result from the tip side detection sensor 44 as a whole. To do. Here, if the set temperature of the water temperature setter 17 is set as a target temperature suitable for breeding as described above, and the set temperature of the water temperature setter 40 is slightly higher than the set temperature of the water temperature setter 17, the proximal-side control unit 29 While the normal water temperature control is carried out, the proximal end side thyristor 19, the proximal end side control unit 29, etc. fail, and the heating wire 37 continues to be energized. Thus, limit control for stopping energization of the heating wire 37 can be performed. Since the heater unit 38 only needs to perform limit control in this way, an inexpensive low-accuracy sensor can be used as the distal end side detection sensor 44, and the distal end thyristor 41 has a switching operation frequency between conduction and cutoff on the proximal end side. Since there are few compared with the thyristor 19, it is hard to break down and can function reliably as a limiter.

  Reference numeral 51 denotes an auxiliary heater built in the case 39, and this auxiliary heater 51 is installed in the vicinity of the front end side detection sensor 44. Since a small amount of electric power is always supplied to the auxiliary heater 51 after the power is turned on, a small amount of heat is radiated from the auxiliary heater 51.

  Thus, if the base end side detection sensor 23 is always heated by the auxiliary heater 31 and the front end side detection sensor 44 is always heated by the auxiliary heater 51, the water when the water W disappears (energization in the air). Can be prevented twice. In addition, such a base end side detection sensor 23 and a front end side detection sensor 44 are repeated repeatedly because the temperature decreases to the water temperature and automatically returns to the normal state when the detection unit 21 and the heater unit 38 are submerged in the water W again. It is possible to prevent airing. The above-described heating wire 37, case 39, tip side thyristor 41, tip side detection sensor 44, DC power supply circuit 46, tip side control unit 48, and auxiliary heater 51 constitute the heater unit 38 as a whole.

  Here, the base end side control unit 29, more specifically, the gate circuit 27, conventionally uses a zero cross pulse drive circuit, but in the first embodiment, it is continuous using a photocoupler or the like (pulse A DC current circuit that generates a DC current that does not return to zero is used. When the gate current for the base end side thyristor 19 is a continuous DC current in this way, the base end side thyristor 19 is held at a holding current (several hundred mA or more) while the gate current is input to the base end side thyristor 19. ), That is, even if the value of the current flowing through the proximal-side conductive wires 12 and 13 decreases to less than the holding current, the conductive state can be established.

  Here, in order to reduce noise, the DC current described above is preferably a zero cross in which the rising timing of the DC current is synchronized with the vicinity of the zero point of the AC voltage, and the value is also preferably a constant value. On the other hand, since there is no problem even if the gate circuit 47 is limited by the holding current, an inexpensive zero-cross pulse driving circuit that has been conventionally used is used. As a result, as the heater unit 38, a heater unit that has been commercially available in a unitized state can be used as it is.

  The base-side conductive wires 12 and 13 and the distal-side conductive wires 34 and 35 described above constitute a pair of conductive wires 54 and 55 in which the plug 14 is connected to the proximal end and a heating wire 37 is provided between the distal ends. However, the current-carrying wires 54 and 55 are cut between the proximal-side thyristor 19 and the distal-side thyristor 41 as described above, and the proximal-side cut end (the distal-end of the proximal-side current-carrying wires 12 and 13 is the distal end). ) Is provided with the output socket 15 of the connector 56, and the input plug 36 of the connector 56 is provided at the distal end cutting end (the proximal end in the distal end side conducting wires 34 and 35). When the input plug 36 is inserted into the input socket 36, it is coupled, and when the input plug 36 is pulled out from the output socket 15, it is separated.

  With such a structure, when either the base end side thyristor 19 or the front end side thyristor 41 or the like fails, it can be dealt with by simply replacing the control unit 18 or the heater unit 38 on the fault side. . Moreover, since the heater unit 38 has been commercially available as described above, it can be used as it is.

  60 is connected between the base end side thyristor 19 and the front end side thyristor 41, here a pair of conductive wires 54 and 55 (base end side conductive wires 12 and 13) between the base end side thyristor 19 and the output socket 15 are connected. The connection line 60 is housed in the case 16 of the control unit 18, and a light start load 61 is provided in the middle thereof. Here, when the gate current from the gate circuit 27 with respect to the base end side thyristor 19 is a continuous DC current as described above, the base end side thyristor 19 becomes conductive regardless of the holding current (several hundred mA or more). The impedance value of the light start load 61 is considerably smaller than the tens of MΩ described in the background art, that is, even when the load is light, while the gate current is being output from the base end side control unit 29 (gate circuit 27), The end side thyristor 19 can be continuously brought into a conducting state.

  In addition, as described above, the proximal-side thyristor 19 becomes conductive regardless of the holding current due to the continuous DC current, so that the impedance value of the light starting load 61 is made larger than the light starting load (about 200Ω) described in the background art. However, the entire water temperature control device including the base end side thyristor 19 can be operated normally. As a result, the amount of heat generated from the light start load 61 when energized is reduced to a small amount of heat that does not require forced cooling. be able to.

  Here, as the light start load 61 described above, a fixed resistor, a variable resistor, a double-wave rectified DC constant voltage circuit using a diode bridge, an inductance such as a transformer, an electrostatic capacitor, an electrostatic capacitance such as a line filter, Combinations of these can also be used. The light starting load 61 is provided on the output side of the proximal thyristor 19, but is provided only on the input side of the distal thyristor 41, or on both the input side and the output side of the proximal thyristor 19. Further, it may be provided on both the output side of the proximal end side thyristor 19 and the input side of the distal end side thyristor 41.

  The impedance value of the light start load 61 is preferably in the range of 10 kΩ to 500 kΩ. The reason is that if the value is less than 10 kΩ, forced cooling means may be required due to heat generated from the light start load 61 depending on the type of electronic components such as the proximal thyristor 19, while if it exceeds 500 kΩ. This is because some types of the base end side thyristor 19 cannot be activated. However, if it is in the range of 10 kΩ to 500 kΩ as described above, the proximal end thyristor 19 can be reliably operated while effectively suppressing heat generation.

Next, the operation of the first embodiment will be described.
Now, it is assumed that the plug 14 is inserted into the outlet of a commercial AC power source, and the detection unit 21 and the heater unit 38 are buried in the water W of the water tank 11 for breeding ornamental fish. At this time, the base end side detection sensor 23 detects the water temperature of the water W, and outputs a detection signal corresponding to the water temperature to the comparison circuit 24. On the other hand, the water temperature setter 17 is a set temperature ( A setting signal corresponding to the target temperature is output to the comparison circuit 24. As a result, the comparison circuit 24 compares the temperature detected by the base end side detection sensor 23 with the set temperature set by the water temperature setter 17, and at this time, when the detected temperature is lower than the set temperature, A gate current (continuous DC current) is output from the gate circuit 27 to the base end side thyristor 19 to make the base end side thyristor 19 conductive regardless of the holding current.

  At this time, since the set temperature of the water temperature setter 40 is set slightly higher than the set temperature of the water temperature setter 17 as described above, a gate signal is always input from the gate circuit 47 to the tip side thyristor 41, The tip side thyristor 41 is in a conductive state. As a result, the heating wire 37 is energized, the heating wire 37 generates heat, and the water W is heated.

  When the water temperature of the water W rises and the detected temperature of the base end side detection sensor 23 exceeds the set temperature (target temperature) of the water temperature setter 17, the comparison circuit 24 stops the output of the gate current from the gate circuit 27. Let As a result, the base end side thyristor 19 is cut off, and energization to the heating wire 37 is cut off. In this way, the water W in the water tank 11 is controlled to the set temperature (target temperature), and an environment suitable for breeding ornamental fish is provided.

  In this way, when the water temperature of the water W is controlled to the set temperature of the water temperature setter 17, the electronic components constituting the control unit 18, such as the base end side thyristor 19, the base end side detection sensor 23, the base end side control Even if one of the sections 29 fails and the proximal thyristor 19 remains in the conductive state, the control becomes impossible, but even if the control unit 18 fails in this way, the water temperature is increased by continuous heating of the heating wire 37. When the water temperature rises to the set temperature of the setter 40, the gate signal output from the tip side control unit 48 to the remaining tip side thyristor 41 that has not failed stops and limit control is performed, so that the water temperature control is safe Done.

    FIG. 3 is a diagram showing Embodiment 2 of the present invention. In this embodiment, intermediate conduction wires 62 and 63, a detection unit 64, and an intermediate control unit 65 having the same configuration as the front-side conduction wires 12 and 13, the detection unit 21, and the control unit 18 described in the first embodiment are provided. It is provided between the control unit 18 (base end thyristor 19) and the heater unit 38 (tip end thyristor 41). In this way, an intermediate thyristor that constitutes a part of the intermediate control unit 65 is provided on the conductive wires 54 and 55 between the proximal thyristor 19 and the distal thyristor 41, and the intermediate thyristor is built in the detection unit 64. If the control unit is controlled by an intermediate control unit that outputs a continuous DC current as a gate current and a light start load similar to the light start load 61 is provided in the intermediate control unit 65, the water temperature is tripled. It can be controlled safely, and air-splashing can be prevented by triple, further improving safety. Here, the water temperature control apparatus having such a structure usually controls the water temperature to, for example, 26 ° C. by the control unit 18 on the base end side, and higher than the control unit 18 by the intermediate control unit 65, for example, 28 ° C. The water temperature is controlled, and limit control of, for example, 36 degrees C is performed by the heater unit 38 on the front end side.

    FIG. 4 is a diagram showing Embodiment 3 of the present invention. In this embodiment, the base end side detection sensor 23 and the auxiliary heater 31 described in the first embodiment are housed in the case 39 of the heater unit 38, the cords are combined into one, and the control unit 18 (base The conducting wires 54 and 55 are not cut between the end side thyristor 19) and the heater unit 38 (tip side thyristor 41), and are continuous. In this way, the structure becomes simple and the production cost can be reduced.

    In the above-described embodiment, by setting the set temperature of the water temperature setter 17 as the target temperature, the base end side thyristor 19 and the base end side control unit 29 perform normal water temperature control, while the water temperature setter 40 In this invention, the limit temperature is controlled by the tip side thyristor 41 and the tip side control unit 48 by setting the set temperature of the water temperature slightly higher than the target temperature. May be set to the same target temperature, and the normal water temperature control may be performed by the base end side thyristor 19, the base end side control unit 29, the front end side thyristor 41, and the front end side control unit 48 in a double manner.

  In this case, even if either the control unit 18 or the heater unit 38 fails, the remaining normal control unit 18 and heater unit 38 perform normal water temperature control, so that the water temperature is reliably maintained at the target temperature. can do. Further, in the above-described embodiment, the switching temperature of the conduction / shutoff of the tip side thyristor 41 (setting temperature of the water temperature setting device 40) can be changed, but in the present invention, it is a constant temperature (cannot be changed). May be.

  The present invention can be applied to the industrial field of controlling the temperature of water in a water tank.

It is a schematic front view which shows Example 1 of this invention. It is the circuit diagram which represented the circuit with the symbol. It is a schematic front view which shows Example 2 of this invention. It is a schematic front view which shows Example 3 of this invention.

Explanation of symbols

11 ... Water tank 14 ... Plug
15… Base end side connector piece 19… Base end side thyristor
23… Base end side detection sensor 29… Base end side control unit
36… Connector on the tip side 37… Heat
41 ... Front side thyristor 44 ... Front side detection sensor
48… Front end side control unit 54, 55… Conductor wire
60 ... Connection line 61 ... Light start load W ... Water

Claims (4)

    A plug connected to an AC power source is connected to the proximal end, and a pair of energized wires provided with a heating element that generates heat and raises the temperature of the water in the water tank when energized between the distal ends, and provided in the energized wire A basal end thyristor that controls the energization state of the energization line based on the input gate current, and the energization line on the distal end side of the base end thyristor. Outputs a continuous DC current gate current to the proximal thyristor based on the detection results from the distal thyristor that controls the energization state, the proximal and distal detection sensors that detect the water temperature, and the proximal detection sensor. A proximal-side control unit that can output a distal-side control unit that can output a gate current to the distal-side thyristor based on a detection result from the distal-side detection sensor; When the gate current is output from the proximal-side control unit to the proximal-side thyristor, the proximal-side triac is continued. A water temperature control device for an aquarium, comprising a small start load with a small calorific value that is in a conductive state.     The water temperature control device for an aquarium according to claim 1, wherein an impedance value of the light starting load is in a range of 10 kΩ to 500 kΩ.     A pair of conducting wires are cut between the base end side thyristor and the front end side thyristor, a base end side connector piece of the connector is provided at the base end side cut end, and a front end side connector piece of the connector is provided at the front end side cut end. The water temperature control device for an aquarium according to claim 1, wherein the base end side and the distal end side connector pieces can be coupled and separated.     The water temperature control device for an aquarium according to claim 1, wherein normal water temperature control is performed by the base end side control unit, and limit control is performed to stop energization when the water temperature becomes high by the front end side control unit.

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