JPS6030927A - Electric heater device - Google Patents

Abstract

PURPOSE:To enable an efficient and uniform heating of water of specified volume as much as possible by a method wherein an electric heating part is provided at least a part of a container storing a specified volume of liquid through a thin insulator and a semiconductor device is installed at the electric heating part. CONSTITUTION:As an input comparative voltage for a differential amplifier 10, the same voltage as the output of the amplifier 8 corresponding to the hot water setting temperature at the heating part is set in advance by a variable resistor 12. When the hot water temperature at the heating part is decreased less than the predetermined value, the output of the differential amplifier 10 becoms a positive value, this value of voltage is amplified with the amplifiers of Tr1 and Tr2 and then a relay for the power supply switch is turned ON. It is possible to design that in case than a gate voltage of an electrostatic induction transistor is varied by a system in which the output from the differential amplifier 10 is fed to the resistor of R1 in series with or in parallel to it and when the hot water temperature is increased more than the desired temperature, the electrostatic induction transistor is turned off and thus the oscillator 4 is terminated.

Description

[Detailed description of the invention] TECHNICAL FIELD The present invention relates to a water heating device using electric heating.

Gas-fired water heaters raise the temperature of water in a relatively short period of time, so they are very convenient devices and are already used in many households and even business hours.

On the other hand, if we look at the recent state of urban and regional development, there is a tendency for the number of large apartment complexes, buildings, and underground malls to increase. Numerous examples have shown that if gas leaks or incomplete combustion occur in such large apartment complexes, buildings, or underground malls (of course, residential areas, etc.), this can lead to very serious accidents. It is as it is.

Especially in times of disasters, accidents caused by broken or cracked gas pipes occur, so even though gas-heated water heaters are convenient, they are not necessarily desirable. At that time, gas pipes in Sendai City were destroyed and cracked everywhere. It is a well-known fact that this caused a gas leak and the city authorities immediately cut off the gas supply, and it took a month to restore the gas supply. By the way, electricity was restored within four days.

Therefore, the emergence of a heating type water heater that does not use gas is desired, but as a heating method that does not use gas, it is most appropriate to use electric heating means. Moreover, considering safety, efficiency, and the cleanliness of the air, the purpose of the present invention is to use a solid-state element to heat a fixed amount of water without using gas heating. , or an electric heating device using solid-state elements to heat any liquid outside the water world. The inventor of the present application has already disclosed in Patent Application No. 102048 (name of the invention, electric water heater) of 1981 that ``through a thin sewn body in a container through which water flows,
We proposed an electric water heater characterized by including a semiconductor device in an electric heating section consisting of a heater made of a resistor or a coil made of a conductor.

However, when trying to safely heat a certain amount of water to a predetermined temperature, such as in a domestic bath, using the above device as is is difficult due to efficiency, safety, and resistance to radio interference. It is not necessarily optimal in such aspects.

That is, in the above-mentioned device, since the water is designed to give a predetermined temperature difference ΔT while flowing from the inlet to the outlet of the water heater, the number of turns of the high-frequency coil increases, and the load as a high-frequency oscillator increases. Due to the high impedance, strict radio wave shielding is required. Furthermore, since the heating section is shaped like a serpentine tube, when used in a bath, there is inevitably a large temperature difference between the bathtub and the heating section. In a bath, rather than increasing the temperature difference ΔT, it is desirable to heat the entire water temperature as uniformly as possible, and to have a high conversion efficiency of the output from the high frequency oscillator into heat.

The present invention relates to an improved electric water boiler capable of heating a given amount of water as efficiently and uniformly as possible.

Although the aforementioned home bath is a specific example, it is not necessarily limited to a bath. How to heat a certain amount of water to a certain temperature? It goes without saying that it can be used for all kinds of liquids, and it goes without saying that it can be used not only for water but also for other liquids.

In general, the issues with electric water heaters are responsiveness and efficiency. Particularly in the case of the electric heating method, two important points are the structure of the heat generating part and the heated body and the efficiency of the heat generating part. In order to improve responsiveness, it is preferable that the heat generating portion be in contact with the heated object directly or through a thin insulator.

As an efficient heating means, it is suitable to use a solid-state element as an additional heat source for the temperature control device, as described in the above-mentioned patent application. Furthermore, when considering the efficiency and safety of solid-state devices, the recently developed electrostatic induction thyristor is the most suitable, but the electrostatic induction transistor also has low output voltage and resistance, making it difficult to obtain extremely efficient high-frequency oscillation. Therefore, it is suitable for the purpose of the present invention. In addition, a normal SiRISC transistor, a 1<ipolar transistor, or a field effect transistor may be used.

Next, we will discuss what considerations need to be made in the case of baths with electric heating.

Normally, the amount of water required for a bath in each household is 2501, but in cold seasons, 250 J of water at about 15°C is heated to 40°C.
The calories required to raise the temperature to 25°C are as follows:

2.5 X 10' X 10' (CC) X 2.
5 X10' = 6-25 X 10' Ca1 = 2.6125 X 10 ri Jou 1 The time required to provide this much energy with, for example, 5 kW of power is as follows.

= 1.45 hours = 1 hour 27 minutes If given using the general formula, V (7) of water will be converted to power P (kW).
Then, the time t required to raise the temperature to T is .

It takes 1 hour and 27 minutes to boil the water in the bathtub, and if you forget the time to turn it on again, you might not be able to boil the water easily.

Therefore, in the present invention, the bath can be turned on at any time, such as in the morning or afternoon, and the water temperature can be automatically controlled. That is, the present invention provides a device that sets a bathing time in advance, programs it to turn on at a time sufficiently earlier than the bathing time, and automatically heats the water to a predetermined temperature.

A specific example of the above invention is shown in FIG.

1 is a bathtub, 2 is a heating section, 3 is an RF heater coil, 4 is R
F oscillator, 5 is a power switch, 6 is a stainless steel tube, 7 is a temperature sensor, 8 is an amplifier 9 is a reference voltage, 10. is a differential amplifier.

2 is a pipe forming a heating section. The same water or hot water as that in the bathtub is stored in this tub. In other words, in Fig. 1, water or hot water from the bathtub 1 passes through it, rises as it is heated by high frequency waves from the RF heater coil 8, and returns to the bathtub from the top. The temperature is raised repeatedly.

Next, heating section 2, RF heater coil a, RF in FIG.
The oscillator 4 and power switch 5 are connected to the electric water heater in some respects, and the main points will be explained below.

Humiliation special 1! ! FIGS. 3 and 9 in No. 102048 are shown in FIGS. 2 and 3 of the present application, respectively. That is, FIG. 2 shows an embodiment of a heating section of a high-frequency induction heating type electric water boiler designed to give a predetermined temperature difference ΔT to running water. Water 11 flows into the pipe 12 and coil 13, is heated by induction heating, and flows out. In Figure 2, 1
It is constructed by bending a pipe to a length of about 7 to 18 ffi, and has a total length of approximately 1 m. The planar size can be approximately 15 x 20 crd.

However, when a certain amount of water is circulated and gradually heated, as in a bath, it is not necessary to raise the running water to a considerably high temperature within the heating section as shown in FIG. That is, the water in the bathtub 1 may be circulated through the heating section 2 shown in FIG. 1 while being heated sequentially from the bottom to the top. Therefore, this circulation must be carried out efficiently. Also, when considering home use, it is recommended to use a 100V direct rectification, 140V or 280V power supply with voltage doubler rectification, and use a power supply of several 10V.
From the perspective of a semiconductor device that performs high frequency oscillation of A, this results in extremely low impedance driving.

Therefore, as shown by the RF heater coil 3 in FIG. 1, it is better to reduce the number of turns in the coil so that the impedance matching is the best. That is, the smaller the number of turns, the lower the impedance. Usually, the number of turns in the coil is as low as 1 to 10 turns.

The RF heater coil 3 and the intestinal tract, that is, the heating section 2, are electrically insulated. For example, a copper wire coated with enamel, formal, or other common insulating material that can withstand relatively high temperatures, or a hollow steel tube with cooling oil inside can be used as the coil.

Comparing Fig. 1 and Fig. 2, not only is the number of coil turns reduced, but the heating part is not curved but is a vertical cylinder.

Natural circulation of water from the bathtub is easily carried out from the bottom to the top, and the temperature difference between the bathtub 1 and the heating section 2 can be kept small.

If the temperature sensor 7 is placed below the RF heater coil 3 as shown in FIG. 5, the temperature will approach the temperature of the bathtub 1 and high frequency induction can be avoided.

In the case of a domestic bath, the simplest method is to shield the outside with metal to prevent radio interference caused by the high frequency induced to the outside from the RF coil 3 or RF oscillator 4.
The figure shows an example in which water also passes through the outside of the RF coil 3. A is a cross-sectional view, and b is an elevational view.

In any case, it has a small Kozuru-Kuhn number and low impedance, so the high frequency voltage applied to the coil is low, making it difficult for radio wave interference to occur. Although the heating method described above uses a coil, a resistor may be used instead of the coil as shown in FIG. Resistor 1 in Figure 7
is impedance, which in this case is low resistance silicone!・A rod is used, and in order to heat the water efficiently, the hot water surrounds the silicone rod. Norikonin 1 to rod 3 are electrically shielded from the water-containing part by an insulating insulator 4 or the like. In this case as well, what is applied to the resistor is a high frequency voltage from the oscillator, and the frequency of the RF oscillator 40 in Figure 1 is determined by a capacitor C and a resistor R. In some cases, it is a controlled rectifier.

When using a coil, the advantage is that the pipe or water can be directly heated by high-frequency induction.However, for use in conditions where high-frequency induction is extremely difficult to use, the resistance heating method described above is recommended because it uses a relatively low frequency. I feel well. Next, in order to heat to a predetermined temperature, a stainless steel tube 6 with a temperature sensor 7 hermetically sealed is inserted into the tube of the heating section 2 shown in FIG. It is extracted electrically as a current. The output of the processor 7 is amplified by an amplifier 8 and input to a differential amplifier 10. The reference voltage 9 is a variable reference voltage corresponding to the set value of the temperature of the hot water. If the output of the DC amplifier 8 is higher than the voltage of the reference voltage 9, the relay of the power switch 5 is activated by a positive current from the differential amplifier 10. The RF oscillator 4 is activated by driving and turning on the power.

An example of the configuration of the part that turns ti ON and OFF based on the output of the temperature sensor is shown in FIG. 4, and is simple. The temperature sensor 7 shown in FIG. 1 is made of, for example, a silicon diode and is integrated with an amplifier 8, and is commercially available, for example, AD590M. In that case, a current proportional to temperature is obtained, which is about 800 μA at 25 °C and 1 °C per temperature change.
μA increases. However, if the amplifier 8 is inside the heating section.

Since high-frequency power can cause significant malfunctions, it is preferable that the temperature sensor 47 and the amplifier 8 be separate units.

The comparison voltage input to the differential amplifier 10 is set using a reference voltage 9 using a variable resistor 12 to the same voltage as the output of the amplifier 8 corresponding to the set temperature of the hot water in the heating section. When the temperature of the hot water in the heating section falls below the set temperature, the output of the differential amplifier 1θ becomes positive, and the output is amplified by the amplifiers Tr+ and Trm, and the relay of the ti switch is turned on.

Conversely, when the water temperature exceeds the set temperature, the output of the differential amplifier 10 becomes negative, and because of the diode clipper 10, T r +
The input current to becomes zero and the relay is turned off. As described above, the water temperature in the heating section is heated until it reaches the set temperature, and after that, when the temperature drops, the power is turned on.

The high frequency oscillator using a static induction transistor or a static induction thyristor described in Japanese Patent Application No. 102048 may be used as the J-land oscillator portion. An example of the circuit is shown in FIG. (Figure 3 is Figure 9 of Tokuiso Purpose No. 102048) As is already known, high-frequency oscillators using electrostatic induction transistors and electrostatic induction transistors have extremely high efficiency and are small in size. However, since the impedance is low, it can be driven at a low voltage, which is particularly advantageous for heating a certain amount of water, such as in a bath, as already mentioned in this application.

In Figures 1 and 4, the power is turned on by the output of the sensor.
, let's talk about the case where it is turned off. This method is an effective method that does not waste power, but since it uses mechanical contacts called relays, it must be taken into consideration that the relays will deteriorate over long periods of use. An example of a device that does not use a relay is the output of the differential amplifier 10 shown in FIG.
! It may be fed back to the oscillator section 4 instead of being fed back to the power supply section.

Specifically, the gate voltage of the static induction transistor is changed by, for example, connecting the output of a differential amplifier in series or parallel to the R3 resistor in Figure 3, and when the water temperature rises above a predetermined temperature, the static It can be designed so that the induction transistor turns off and the oscillator stops.

Next, the power supply section 5 shown in FIG. 1 will be described.

This power supply unit has a built-in program timer, and if you set the time for the water temperature to reach a predetermined temperature, the power will be turned on a predetermined time earlier. As described above, the water heating device of the present invention uses one electric heating method to heat water;
For example, we have shown that baths are not only disaster-resistant and do not cause radio interference, but are also efficient and can be made to reach a predetermined temperature at any given time.

Of course, this electric water heater can heat not only a fixed amount of water, but also a fixed amount of any liquid.

Therefore, if the purpose is to heat a certain amount of water or a certain amount of liquid in a predetermined greenhouse, this device can be used not only for baths.

For example, if the towels are sterilized and washed at 80"C in a commercial towel washer, it is possible to avoid the accumulation of water scale due to boiling and evaporation of water.

As an example of a liquid other than water, for example, a certain amount of oil can be circulated to keep a greenhouse or the like warm.

It is also possible to keep alcohol and other liquid chemicals at a constant temperature to cause distillation or chemical reactions.

As described above, the electric heating device of the present invention has a wide range of uses and is of high industrial and consumer value.

[Brief explanation of the drawing]

Fig. 1 shows an example of the configuration of an electric heating device using high frequency induction heating, Fig. 2 shows an example of a heating section of an electric heating device using high frequency induction heating, Fig. 3 shows an example of a circuit of a high frequency oscillator, and Fig. 4 shows an example of a circuit of a high frequency oscillator. An example of the configuration of the part that turns the power ON and OFF based on the output of the sensor. Figure 5 shows the location of the temperature sensor, and Figure 6 shows an example where water also passes outside the RF coil. The plan view, FIG. 7, is an example of an electric heating method using a resistor. Figure 5, Figure 6, Figure 7

Claims (9)

[Claims] (1) A container storing a certain amount of liquid, an electric heating section consisting of a coil made of a conductor or a heater made of a resistor, provided in at least a portion of the container via a thin insulator, and connected to the electric heating section. An electric heating device comprising a semiconductor device. (2) The electric heating device according to claim 1, wherein the semiconductor device is a static induction transistor or a static induction transistor. (3) The electric heating device according to claim 1, wherein the electric heating section constitutes a high frequency oscillation circuit. (4) The electric heating device according to claim 1, wherein the liquid is water. (5) A temperature sensor and a program timer section for heating the liquid to a predetermined temperature by a predetermined time, and a section that controls the output of the electric heating section based on the output of the temperature sensor. The electric heating device according to claim 1, characterized in that: (6) The electric heating device according to claim 1, wherein the heating section is formed of a low impedance coil of 10 turns or less or a low resistance silicon knit rod. (7) The electric heating device according to claim 1, wherein the heating section is arranged so that water rises vertically in order to facilitate circulation of the liquid in the container. . (8) The electric heating device according to claim 1, wherein the heating section is designed so that water passes outside the coil or resistor. (9) The part that controls the output is! ! Turn on the source
The electric heating device according to claim 5, which is a relay that turns FF. 6. The electric heating device according to claim 5, wherein the temperature sensor is a semiconductor diode and is in contact with water in the heating section through a protection tube.