JPH10321345A - Water tank heat reserving apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably prevent the occurrence of a fire accident or the like due to an excessive temperature rise by detecting a water temperature in a short time by breaking or turning on a power circuit of a heating heater by detecting heat by the heating heater arranged in a glass protective tube through a temperature sensor. SOLUTION: In a hollow cylindrical glass protective tube 1, a nichrome wire of a heating heater 2 is arranged in a folding-back shape on the surface- back along both surfaces of a base board 8 of an insulating material extending over an almost half of the total length of the glass protective tube 1, and a temperature sensor 3, a diode 4a and a temperature fuse 4b are connected to its both ends. In a normal condition where water exists in a water tank, the glass protective tube 1 is heated along the heating heater 2, and a heater 2 nonexistent part is cooled by surrounding water. When a heat reserving apparatus is exposed to the atmosphere since the water in the water tank runs out, the temperature sensor 3 arranged in the glass protective tube 1 senses its temperature rise, and cuts off current-carrying to the heating heater 2, and prevents an overheat condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aquarium warming device for keeping aquarium fish and the like in an aquarium in the cold season.

[0002]

2. Description of the Related Art In general, tropical ornamental fish cannot survive unless the water temperature is 20 ° C. or higher, and a warming device (heater) is used in a cold season when the temperature is lower than 20 ° C. Such an aquarium warming device not only keeps the aquarium warm, but if the aquarium is damaged or leaks due to an earthquake or operation error such as the Great Hanshin Earthquake, there is no water in the aquarium and the heater overheats. There is a known danger that a fire may occur, and a heat retention device is provided with an overheat prevention device so as not to cause an accident leading to such a fire.

[0003] In this overheat prevention type heat insulation device, a heating heater is inserted into a glass protective tube, and a thermistor type temperature sensor, a connection cord thereof, and a power cord to the heater are integrally provided near one end thereof. The heater portion is filled with fine-grained sand so that the nichrome wire of the heater does not touch the glass and heat conduction is performed uniformly.

[0004] The temperature sensor is provided at a distance of about several cm from the end of the heater so as to prevent the heat of the heater from being conducted directly, and the thermistor, the connection cord and the power supply cord are collectively fixed with silicon. Alternatively, similarly to the heater, fine sand is packed to insulate. The glass protection tube is provided over the heater unit and the temperature sensor unit. In some cases, a protective tube made of metal is further covered on the outside, and both ends are closed with rubber caps.

[0005]

However, in the above-mentioned conventional overheat prevention type heat retaining device, the temperature sensor is connected to the end of the heater by several cm as described above in anticipation of a risk of a fire accident in an overheated state. When the temperature sensor detects the temperature exceeds the set temperature, the controller shuts off the power supply circuit to the heater and shuts off the power even when the temperature sensor detects the temperature exceeds the set temperature. To prevent overheating above the set temperature.

However, when such a heat retaining device is actually exposed to the atmosphere and energized, it takes a considerable time until the temperature sensor rises to the set temperature, but the outer peripheral temperature of the heater portion is actually rapidly increased. It rises to several hundred degrees. This is because the heater of the conventional heat retaining device is similar to a general heater such as an electric stove, in which the surface of the nichrome wire in the glass protection tube is red and glowing even during normal operation in water (generally, about 400 ° C.). This is because the temperature is set to be as high as the above. If such a high-temperature heating type heater is provided, the temperature sensor is affected, so that the temperature sensor is naturally provided at a certain distance or more from the heater, and the space between them is filled with sand or the like to provide a heat insulating space. .

However, when such a heat insulating space is provided, even when the water in the water tank is exhausted and the water is exposed to the atmosphere, heat transfer to the temperature sensor is slow, so that the power supply circuit is not immediately shut off, The temperature of the heater portion excluding the sensor rises rapidly, and the temperature of the outer periphery of the glass protective tube rises to several hundred degrees. If the water in the water tank runs out in such a condition due to an earthquake or the like, or if the heat retention equipment is taken out of the water tank and left near a flammable object, it may still cause a fire. However, its overheating prevention function is not always satisfactory.

The present invention solves the above-mentioned problem of the conventional heat retaining device by providing a simple member and setting the internal temperature of the heater to a non-red heat temperature. An object of the present invention is to provide a safe aquarium warming device that is not connected.

In addition, a current limiting means for setting the internal temperature to a non-red heat temperature is provided in the safe water tank heat-insulating equipment to shorten the length of the heater coil, and the water tank has a compact shape within a standard size as a whole. Another object is to provide a warming device.

[0010]

According to the present invention, there is provided a temperature sensor in which a heater is provided in a glass protective tube and an outer periphery is surrounded by a heat conductive film near one end of the glass protective tube. Provided in contact with the inner periphery of the protective tube and one end thereof in contact with the end of the heater, the heater has a wire diameter, a winding diameter, and a length having a resistance value such that the maximum temperature in the glass protective tube when energized in water is a non-red hot region. When the water temperature in the water tank detected by the temperature sensor falls below the set temperature, the heater is energized to maintain the water temperature at the set temperature, and when exposed to the atmosphere, the heat from the heater is detected by the temperature sensor. This is a water tank warming device configured to detect the current and cut off the power supply to the heater to prevent overheating.

According to the aquarium warming device of the present invention having the above-described structure, it functions similarly to the conventional one in protecting ornamental fish such as tropical fish in the cold season. That is, the water tank warming device is installed in the water in the water tank while the main power supply is connected as in the related art, and when the temperature of the water becomes higher than the temperature set by the temperature sensor (for example, 25 ° C.), the temperature sensor is used. The power supply circuit of the heater is cut off by the detection signal, and when the temperature becomes low, the power supply circuit is turned on again, and all the operation is performed by the signal of the temperature sensor as long as there is water in the water tank.

The change in water temperature changes substantially corresponding to the change in atmospheric temperature, and changes depending on the season and the time of day, but the heating capacity of the heater becomes lower than the temperature set by the temperature sensor. However, it does not mean that the temperature must be large enough to be rapidly heated to the set temperature or more immediately, but may be large enough to be able to maintain the water temperature at or above the set temperature by heating slowly.

One guideline for setting the heat capacity of the heater to heat in such a suppressed state is to limit the current so that the nichrome wire of the heater is in a non-red hot state (about 300 ° C.). That is. As described above, when heating is performed in a non-red heat state with a nichrome wire, the outer periphery of the heater portion is always cooled with water during normal operation in water because the heating temperature is low, and the temperature sensor can be cooled without providing an insulating space. , The temperature sensor is less affected by the heater.

Providing a temperature sensor at the end of the heater without providing the heat insulating space means that when the water in the water tank runs out, the temperature rise of the heater can be directly detected, so that the heat retaining device is exposed to the atmosphere. This is convenient for detecting the state of heating by the heater as early as possible in a short time.

However, if a temperature sensor is provided at the end of the heater without providing a heat insulating space, the influence of a slight heat leak from the heater is inevitably received. Need to be shut off. For this reason, in the present invention, the temperature sensor is accurately and faithfully detected as long as there is water in the water tank, by surrounding the temperature sensor with a heat conductive film material and providing it in contact with the inner periphery of the glass protective tube. In addition to this, the temperature sensor is also cooled to cancel the influence of the heat leak from the heater inside the glass protective tube.

By adopting the above configuration,
According to the heat retaining device of the present invention, even if the water tank is damaged due to an earthquake or the like and the tank is exposed to the atmosphere, the overheated state is detected early, and the power supply to the heater is cut off, so that a fire accident or the like can be reliably generated. To prevent. For this reason, the overheating state stops at a temperature much lower than the conventional one, and does not reach an abnormally high temperature.

When the coil of the above-mentioned heater has a wire diameter, a winding diameter, and a length having a resistance value at which the maximum temperature in the glass protective tube when energized in water is in a non-red-hot region, actually, There are two ways.

One is to form a heater by completely enclosing a coil having a wire diameter, a winding diameter and a length having a resistance value in the non-red heat region in a space allowed as a heater in the glass protective tube. Is the case. When a nichrome wire coil designed for a general heater is used as it is with a rated capacity, the coil surface temperature becomes 60%.
Since the device operates in the red heat region of 0 to 700 ° C., in order to operate in the non-red heat region, the coil diameter may be increased by increasing the wire diameter, the winding diameter, and the length, particularly, the coil resistance.

Therefore, the conventional coil having a large rated capacity (for example, 150 W, 200 W) is packed with a coil whose length is close to the limit length. The number of folded columns is increased to three columns and four columns. As described above, by increasing the number of folded rows, the coil resistance value is increased to operate in the non-red heat region.

Another method is to increase the length of the nichrome wire coil and increase the coil resistance instead of increasing the coil length to limit the current corresponding to the current value limited by the increasing resistance value. This is a method of inserting current limiting means into the power supply circuit. As the current limiting means, a diode is used when the rated capacity is small (60 W), and a triac is used when the rated capacity is 100 W or more.

However, conventionally, generally used heat insulation equipment has a glass protective tube length of about 200 to 230 m.
m, an inner diameter of 13 mm, and an outer diameter of 15 mm. Of these sizes, the length is extremely long (for example, twice or more),
Alternatively, it is difficult to increase the diameter in the current situation where the above dimensions are generalized.

In the conventional heater of the rated capacity, the size of the substrate for mounting the nichrome wire coil is limited by the watertight cap, the temperature sensor, the heat insulating space, and the like at both ends. About 12 from the need to provide
It is about 0 to 130 mm, and it is difficult to mount the nichrome wire coils in one row with the above substrate length.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the appearance of the water tank warming device of the embodiment, and FIG. 2 shows its plan view and longitudinal sectional view. As shown in the figure, a water tank warming device is a hollow cylindrical glass protective tube 1.
A heater 2 using a nichrome wire therein, a temperature sensor 3 provided near one end in the glass protection tube, a diode 4a for limiting the current of the heater 2, and a temperature sensor 3
And a thermal fuse 4b inserted for safety in the event of a failure. Both ends of the glass protection tube 1 are sealed with a waterproof rubber cap 6, and a rubber mounting base 7 with a suction cup is provided.
Are fitted.

As shown in FIG. 2, the nichrome wire of the heater 2 is provided on both sides of an insulating substrate (mica plate) 8 which extends over substantially half of the entire length of the glass protective tube, and is turned back and forth. A temperature sensor 3 at each of its ends,
The diode 4a and the thermal fuse 4b are connected, and a power cord 9 is connected to each end. The gap between the heater 2 and the glass protection tube 1 is filled with fine sand 8a so that the nichrome wire does not directly touch the glass protection tube 1 and evenly distribute heat transfer.
Both ends of the glass protection tube 1 are filled with silicon filling portions 6.
The space 6b close to the left end of the heater 2 and the end of the nichrome wire of the heater 2 is also filled with fine sand 8a.

The nichrome wire of the heater 2 has a wire diameter,
The winding diameter and length have a heating capacity of the rated output during normal operation in water, and have a resistance value such that the maximum temperature during energization is in a non-red hot region. More specifically, in the example shown in the figure, a rated output of 60 W, a coil wire diameter of 0.23 mmφ, a winding diameter of 5 mmφ, and a length of 80 mm are used. Fold it upside down and set it). This heater will be described later in more detail.

The temperature sensor 3 comprises a temperature switch using a bimetal. The temperature sensor 3 has its outer periphery surrounded by a high thermal conductive film material 5 made of copper, and is provided in contact with the inner periphery of the protective tube 1 and one end thereof in contact with the heater end. The high thermal conductive film material 5 may be any material having a high thermal conductivity such as an aluminum alloy other than copper. The glass protective tube 1 is made of glass having high heat resistance and high strength. The glass protective tube 1 has a length of 150 mm, an inner diameter of 13 mmφ, and an outer diameter of 15 mmφ in the illustrated example.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2A, and FIG. 4 is an enlarged perspective view of the vicinity of the temperature sensor 3 described above. In addition, you may make it cover a metal protection tube on the outer side of the glass protection tube 1. FIG.

The relationship between the size of the water tank and the rated output (W) of the heater is as follows: water volume (width) rated output 80 l (900 mm) 200 W (2.0 A) 60 l (600 mm) 150 W (1.5 A) 35 l ( 450W) 100W (1.0A) 30l or less (small size) Heater of any of the above rated outputs is used with approximately 75W (0.75A) as a guide. In this case, the rated output is 100V AC household power source, continuous Assuming the rating, in the case of 100 W or more, the length of the glass protection tube 1 is about 200 to 230 mm,
Those having an inner diameter of 13 mm and an outer diameter of 15 mm are generally used. For a small water tank of 75 W or less, a water tank shorter than the standard having a length of about 150 mm is used as described above.

The water tank warming device configured as described above adjusts the water temperature in the water tank to a set temperature so as to protect tropical fish and the like in the cold season. However, if an aquarium is damaged by an earthquake or the like, or if water leaks and the heat retention equipment is exposed to the atmosphere,
In general, there is a concern about the possibility of an accident that may lead to a fire due to overheating of the heater 2, but the heat retaining device of this embodiment prevents such a possibility before and completely as follows.

In a normal state where water is present in the water tank, the glass protective tube 1 generates heat along the heater 2,
The empty area is cooled by the surrounding water. Since the glass protection tube 1 heated to a high temperature by the heater 2 is integrally connected to a portion where the heater 2 is not provided, there is a slight leak to the portion where the heater 2 is not provided, and there is a leak from one end of the heater 2. Is directly transferred to the temperature sensor 3 provided therein, and the temperature sensor 3 is heated. However, since this heat leak is usually cooled by surrounding water, the temperature sensor 3 is not affected by the heat leak. , Which senses a temperature approximately equivalent to the water temperature in the aquarium. This is because the temperature sensor 3 is in close contact with the inner wall of the glass via the high thermal conductive film material 5 and is cooled through the glass tube.

In this case, the rated capacity of the heater is limited by the current inserted by the diode inserted into the power supply circuit.
The capacity is not about the rated capacity of continuous W AC but about 70% of the rated capacity. Therefore, the temperature rise by the heater in the normal state is low, and therefore, the temperature sensor 3 is provided in contact with the end of the heater 2. However, heat leakage from the heater 2 to the temperature sensor 3 is small, and is not affected by cooling by surrounding water.

However, when the water in the water tank runs out and the heat retaining device is exposed to the atmosphere, the situation changes greatly. When the surrounding water runs out, the temperature rise of the temperature sensor 3 is not cooled, and the temperature rise is directly transmitted to the temperature sensor 3. For this reason, the temperature sensor 3 provided in the glass protection tube 1 detects the temperature rise, and the temperature sensor 3
The power supply to the heater 2 is cut off via the switch, thereby preventing an overheating state. In this case, the temperature sensor 3
Since is a bimetallic temperature switch, it operates only at the temperature set by the bimetallic metal, and cannot basically change the set temperature.

By the way, such a heat retaining device is a temperature sensor 3
When the temperature rise is detected and the temperature rises above the set temperature, the current is cut off as described above.However, when the water runs out when the current is turned on, the temperature rise is the maximum temperature of the surface of the nichrome wire. 60 in a short time (for example, about 5 seconds)
It reaches the red heat temperature of 0 to 700 ° C., and even the temperature of the surface of the glass protective tube is several hundred degrees, which may cause fire or burns, and may be dangerous.

However, since the maximum temperature of the surface of the nichrome wire is suppressed to a non-red heat temperature of about 270 ° C. in the heat retaining device of this embodiment, the surface temperature of the glass protective tube is 100 to 1 °.
The temperature is about 20 ° C., and the time required to reach the maximum temperature is 60 seconds, which is a long time. Therefore, it does not cause a fire and the safety is sufficiently ensured.

For reference, experimental data comparing the nichrome wire of the present embodiment, whose maximum temperature is set to the non-red hot temperature, with the conventional one are shown below. However, in each case, the measurement was performed under the same condition that the power supply circuit was turned on and off at 25 ° C. in the bimetal temperature sensor 3.

[0036]

[Table 1]

The above-mentioned arrival time is the time from when the power is turned on in a state where the heat retaining device is exposed to the atmosphere to when the temperature reaches the maximum temperature in the energized state. The diameter and length of the heat retaining device are all the same.

Although the length is shown as a close winding length (natural length set and supplied for a general heater), the coil pitch is set to about It is used by extending it to less than twice. This is because the amount of heating is concentrated in the close winding state, so that this heated state is dispersed. This is the same in the comparative example, and is the same in the case of Tables 2 and 3 described later (however, the ratio of the length to be extended according to the magnitude of the rated capacity is, for example, 150 W
Is slightly different from about 1.5 times).

As can be seen from the comparison of the above data, when the normal-temperature insulation device that was operating at the rated power in water was suddenly exposed to the atmosphere, the rated power became the resistance value of the nichrome wire in the normal state. , Is suppressed by the current limit by the diode,
Since the maximum temperature is suppressed to the non-red heat temperature, the surface temperature of the glass protective tube is lowered, and safety is ensured.

In the above embodiment, the rated capacity of 60 W has been described. However, in the case of a rated capacity of 150 W or more, there is a limit to the electric capacity limiting capacity by the diode 4 a as the current limiting means. (See FIG. 5). In this case, the triac 4a 'is inserted into the power supply circuit of the heater coil together with the thermal fuse 4b, and the triac 4a' is separately provided.
A diode 4c for controlling the a 'gate current is provided to supply half-wave rectified current of the power supply circuit as in the case of 60W. 4d is a resistor. Table 2 shows the specifications and the maximum temperature value of the nichrome wire in the case of the rated capacity of 150 W in the same manner as in Table 1 as Embodiment 1 '.

[0041]

[Table 2]

In each of the above embodiments, the current is limited by the diode 4a or the triac 4a ', so that the heating temperature of the heater can be reduced to the non-red heating temperature (4
(Less than 00 ° C). The reason for using the current limiting means is to shorten the length of the nichrome wire coil and compactly store the heater in a glass protection tube of a standard size or less. The purpose is.

Therefore, among the standard sizes of the glass protective tube described above, when the diameter may be slightly increased, the resistance of the heater is increased by lengthening the coil of the heater without using the current limiting means. Fold the coil in 3 rows or 4
They may be stored in rows. In this case, the current is limited only by increasing the length of the coil, and a setting is made so as to be in a non-red hot state.

The coil length and the maximum temperature value for each of the rated capacities of 60 W and 150 W when the coil of such a heater is lengthened are as follows.

[0045]

[Table 3]

Comparing the above data with the values shown in Tables 1 and 2, it can be seen that when the nichrome wire is lengthened, a heater having substantially the same non-red heat temperature can be obtained. Such a design
Regardless of the magnitude of the rated capacity, the following second embodiment can be similarly adopted.

FIG. 6 and subsequent figures show a heat retaining device according to the second embodiment. 6 is an overall schematic diagram, FIG. 7 is a cross-sectional view of a main part, and FIG. 8 is a control circuit diagram. This embodiment uses a thermistor as the temperature sensor 3a, and is different in that a controller 10 for controlling ON / OFF of a power supply circuit at a temperature detected by the temperature sensor 3a is connected by a connection cord 9 '. Is basically the same as the first embodiment. Hereinafter, the different points will be mainly described.

As shown in FIG. 8, the controller 10
It comprises a power supply circuit 11, a comparator 12, a variable resistor 13 adjusted by a temperature setting knob (not shown), and the like. The controller 10 controls the reference voltage and the temperature sensor 3 by appropriately adjusting the variable resistor 13 in accordance with the set temperature.
a and a voltage detected by the comparator 12 is compared and amplified by the comparator 12.
A switch (not shown) in the power supply circuit 11 is turned on in response to the output signal of (1), and the power supply circuit 11 supplies power to the heater 2.

When the water temperature in the water tank becomes equal to or higher than the set temperature due to the heating by the heater 2, the output from the comparator 12 disappears, and the switch in the power supply circuit 11 is turned off to cut off the power supply to the heater 2. Thereby, the water temperature in the water tank is automatically adjusted to the set temperature by the controller 10. The set temperature is set to an appropriate value within a range of, for example, 20 to 35 ° C.

The heat retention apparatus of this embodiment differs from the first embodiment only in that the size and the capacity of the heater 2 are exactly the same as those of the first embodiment, except that the controller 10 can set variously the water temperature in the water tank in a normal state. And therefore the same is true for the effect.

In the second embodiment, similarly to the first embodiment, when the rated capacity is increased to 150 W or more, the triac 4a '
Used in place of

[0052]

As described above in detail, the water tank heat retaining device of the present invention is provided with a temperature sensor in contact with the heater without providing an insulating space between the heater and the temperature sensor in the glass protective tube. The sensor is surrounded by a heat conductive film material, and it contacts the inner circumference of the protective tube so that the temperature of the water can be detected while cooling.The temperature control in the normal state is set to a non-red heat state. ,
Even when exposed to the atmosphere, the heating temperature of the heater is detected by the temperature sensor within a short period of time and the power supply to the heater is stopped. Therefore, it is possible to prevent accidents due to excessive temperature rise completely and completely. There is an effect that an aquarium warming device with high performance can be obtained.

Further, as in the second invention, the length of the coil is shortened by using a current limiting means in the power supply circuit. The advantage is that a compact and safe warming device containing the heating coil can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a water tank warming device of a first embodiment.

FIG. 2 is a plan view and a vertical sectional view of the above.

FIG. 3 is an enlarged sectional view taken along arrows IIIa-IIIa and IIIb-IIIb in FIG.

FIG. 4 is a partial cross-sectional perspective view of the water tank warming device of the first embodiment.

FIG. 5 is a partial cross-sectional perspective view when the rated capacity of the water tank warming device is different from that of the above water tank.

FIG. 6 is a schematic view of an aquarium warming device according to a second embodiment.

FIG. 7 is a cross-sectional view of a main part of an aquarium warming device according to a second embodiment.

FIG. 8 is a schematic block diagram of a controller for the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass protective tube 2 Heater 3, 3a Temperature sensor 4a Diode 4b Thermal fuse 5 High thermal conductive film material 6 Cap 7 Mounting leg 8 Substrate 9 Power cord 10 Controller

Claims (2)

[Claims] 1. A heater is provided in a glass protective tube, and a temperature sensor whose outer periphery is surrounded by a heat conductive film material is provided near one end of the glass protective tube in contact with the inner periphery of the protective tube and one end thereof is in contact with the heater end. The heater consists of a coil with a wire diameter, winding diameter, and length that has a resistance value such that the maximum temperature in the glass protective tube in the water when energized in water is a non-red hot region, and the water temperature in the water tank detected by the temperature sensor is When the temperature falls below the set temperature, the heater is energized to maintain the water temperature at the set temperature, and when it is exposed to the atmosphere, heat from the heater is detected by the temperature sensor and the energization to the heater is cut off to prevent overheating. Aquarium warming device. 2. A current limiting means for limiting a current is inserted into a power supply circuit of the heater, and a current which increases in accordance with a resistance value which is reduced by making a coil length shorter than the set length is limited by the current limiting means. 2. The aquarium warming device according to claim 1, wherein the length of the coil is reduced by means of means.