JPH0763418A - Electrical hot water heater - Google Patents

Abstract

PURPOSE:To provide an electrical hot water heater capable of preventing an excessive boiling of hot water within a heating pipe occurring when an electrical energization is started. CONSTITUTION:An electrical hot water heater comprises a hot water storing tank 1 for storing boiled hot water, a heating pipe 10 having a temperature and flow rate control valve opened at a desired temperature of boiled hot water at an upper flowing-out port 10A, a lower pipe 3 for connecting the lower part of the hot water storing tank 1 with the lower part of a heating pipe 10, and an upper pipe 2 for connecting the flowing-out port 10A of the heating pipe 10 with the upper part of the hot water storing tank 1. In addition, there are provided two electrical heaters arranged within the heating pipe 10 so as to boil up hot water in the heating pipe 10, and a control means 20 for supplying an electrical power to one electrical heater only for a period ranging from a starting of electrical energization to the desired time, making the other electrical heater non-conductive state and supplying electrical power to the two electrical heaters after a predetermined time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric water heater for storing hot water boiled by an electric heater in a hot water storage tank.

[0002]

2. Description of the Related Art Some electric water heaters have an external heating system. The external heating type electric water heater uses a heating pipe provided separately from the hot water storage tank to boil the water. An example of such an electric water heater is shown in FIG. This electric water heater has a hot water storage tank 1 for storing boiled water, a heating pipe 50 for boiling the hot water, an upper pipe 2 connecting the upper part of the hot water storage tank 1 and the upper part of the heating pipe 50, and a lower part of the hot water storage tank 1. The lower tube 3 that connects the lower part of the heating tube 50 is provided.

Further, as shown in FIG. 7, a wax valve 51 is provided as a temperature flow control valve at the outlet 50A in the upper part of the heating pipe 50, and a U-shaped electric heater 52 for boiling water is provided in the lower part. ing.

The wax valve 51 of the heating pipe 50 is shown in FIG.
As shown in (a), a temperature detecting portion 51B having a stretchable portion 51A at the tip and a valve portion 51D that is fully closed by being biased by a spring 51C are provided. Then, when the hot water temperature detected by the temperature detection unit 51B reaches a predetermined temperature, FIG.
As shown in FIG. 5, the expansion / contraction portion 51A extends with respect to the urging force of the spring 51C, and the valve portion 51D is fully opened.

In such an electric water heater, the wax valve 5
When 1 is in the fully closed state, the electric heater 52 boils the water in the heating pipe 50. When the hot water temperature reaches a predetermined temperature, the wax valve 51 detects the hot water temperature and is in a fully opened state. As a result, the hot water in the heating pipe 50 moves to the hot water storage tank 1 by natural convection. That is, the hot water of the heating pipe 50 is
As shown by the arrow A, it flows through the upper pipe 2 and into the upper part of the hot water storage tank 1. The hot water storage tank 1 stores this hot water in the upper part. At the same time, the water in the lower part of the hot water storage tank 1 flows into the heating pipe 50 through the lower pipe 3 as shown by the arrow B. This lowers the temperature of the hot water in the heating pipe 50, and the wax valve 51
Becomes the fully closed state, and the previous operation is repeated again.

As described above, a layer of high temperature water 101 having a predetermined temperature and a layer of low temperature water 102 are formed in the hot water storage tank 1, and the user uses the high temperature water 101.

[0007]

The external heating type electric water heater using a temperature flow control valve such as a wax valve has been found to have the following problems.

In this electric water heater, the wax valve 51 is
The structure is such that it opens when the detected temperature reaches a predetermined temperature, but there is a delay time between the detection of the predetermined temperature and the opening of the valve.

In the electric water heater for forming a layer of high temperature water 101 and a layer of low temperature water 102 in the hot water storage tank 1, the high temperature water 10
Heat transfer from 1 to the cold water 102 occurs. As a result, when the amount of the low temperature water 102 in the hot water storage tank 1 decreases, the temperature of the low temperature water 101 increases. When heating is started in the heating pipe 50 in which the low-temperature water 102 of which the temperature has risen has flowed, as shown in FIG. The water temperature may reach over 100 degrees and the water may boil too much.

After this, the wax valve 51 is opened,
The hot water moves from the heating pipe 50 to the hot water storage tank 1 by natural convection, and the hot water also moves inside the heating pipe 50. This allows
At time T2, the temperature of the hot water in the heating pipe 50 drops. After that, the temperature of the wax valve 51 itself is increased and the water in the heating pipe 50 is boiled by convection, so that the water does not overboil. That is, when the hot water temperature rises after the time T3, the wax valve 51 is opened, and when the hot water temperature drops after the time T4, the wax valve 51 is closed.

As described above, when the hot water in the heating pipe 50 boils, the temperature of the hot water falls below 100 degrees, which is out of the regulation of the electric water heater. However, there is a problem in that the change of the value is caused or the life is shortened.

An object of the present invention is to eliminate the above drawbacks and to provide an electric water heater capable of preventing excessive boiling of hot water in a heating pipe which occurs at the start of energization.

[0013]

In order to achieve the object, a first invention is a hot water storage tank for storing boiled hot water,
A heating pipe having a temperature flow control valve in the upper outlet that opens when the boiled water reaches a predetermined temperature, a lower pipe connecting the lower part of the hot water tank and the lower heating pipe, and an outlet of the heating pipe and hot water storage. In an electric water heater provided with an upper pipe connecting with an upper part of a tank, two electric heaters provided in the heating pipe for boiling the hot water in the heating pipe and one electric heater for a predetermined time from the start of energization And a control unit that supplies electric power to the heater, deenergizes the other electric heater, and supplies electric power to the two electric heaters after a predetermined time.

A second aspect of the present invention is a hot water storage tank for storing boiled hot water, a heating pipe having a temperature flow control valve at an upper outlet which is opened when the boiled hot water reaches a predetermined temperature, and a hot water storage tank. In an electric water heater including a lower pipe connecting a lower part and a lower part of a heating pipe, and an upper pipe connecting an outlet of the heating pipe and an upper part of a hot water storage tank, the hot water is provided in a heating pipe to supply hot water by supplying a predetermined electric power. An electric heater to boil,
Control means for supplying electric power less than the predetermined electric power to the electric heater only for a predetermined time from the start of energization and for supplying the electric heater with the predetermined electric power after the predetermined time.

[0015]

According to the first aspect of the present invention, the control means supplies the electric power to only one electric heater at the time of starting the energization of the electric heater of the heating tube, so that the boiling of the hot water of the heating tube which occurs at the start of the energization is prevented. .

Further, according to the second aspect of the invention, at the time of starting the energization of the electric heater of the heating pipe, the control means supplies the electric heater with an electric power smaller than a predetermined electric power, so that the hot water of the heating pipe generated at the start of the energization. Boiling is prevented.

[0017]

Embodiments of the present invention will now be described with reference to the drawings.

[First Embodiment] FIG. 1 shows a first embodiment of the present invention.
FIG. The electric water heater of the first embodiment includes a hot water storage tank 1, an upper pipe 2, a lower pipe 3, a heating pipe 10 and a control means 20. Further, the control means 20 includes the power supply unit 2
1, a control unit 22 and a switching unit 23.

Hot water storage tank 1 and upper pipe 2 of this electric water heater
Since the lower pipe 3 and the lower pipe 3 are the same as those in the conventional electric water heater shown in FIG.

At the upper outlet 10A of the heating pipe 10, as shown in FIG. 2, a wax valve 11 as a temperature flow control valve is provided.
Is provided. Furthermore, in the lower part of the heating pipe 10,
Two U-shaped electric heaters 12, 13 are provided. The electric capacity of the electric heater 12 is substantially equal to the electric capacity of the electric heater 13, and the electric heater 12 and the electric heater 13 have the same electric capacity.
And the total electric capacity is equal to the capacity of one conventional electric heater. The electric wires 12A and 13A for supplying electric power to the electric heaters 12 and 13 are connected to the switching unit 23 of the control means 20, respectively.

The power supply section 21 of the control means 20 supplies the switching section 23 with electric power for supplying the electric heaters 12 and 13.

The control unit 22 includes a CPU (Central Processi).
ng Unit), ROM (Read Only Memory), RAM (Ran
dom access memory) or the like, and controls the switching unit 23 based on settings for boiling water. The control unit 22 sets the energization start time, the energization time, the amount of boiling water, and the like.

Under the control of the control unit 22, the switching unit 23 supplies the electric power from the power supply unit 21 to the electric heater 12, supplies the electric power to both the electric heaters 12 and 13, or both electric powers. It controls whether the heaters 12 and 13 are turned off.

Next, the operation of the first embodiment will be described.

At the start time of energization of the electric heaters 12 and 13, the control unit 22 starts energization of one of the electric heaters 12 as shown in FIG. 3 (step S1).
Then, the power supply to the electric heater 12 is continued for N minutes (step S2). Here, N minutes is usually between 5 and 10 minutes. When the energization for N minutes is completed in step S2, energization to both electric heaters 12 and 13 is started (step S3). After that, the control unit checks whether or not the set amount of hot water, that is, the set amount of hot water has boiled (step S4).
2 and 13 are turned off (step S5), and the control for boiling water is completed.

In this way, the control unit 22 supplies electric power to one of the electric heaters 12 only for the first N minutes at the time of starting energization, so that it occurs at the time of starting energization.
It is possible to prevent excessive boiling of hot water in the heating pipe 10.

Further, since the boiling water in the heating pipe 10 is prevented from being overboiled, the deterioration of the characteristics of the wax valve 11 can be prevented and the life can be extended.

[Second Embodiment] FIG. 4 shows a second embodiment of the present invention.
FIG. The electric water heater of the second embodiment includes a hot water storage tank 1, an upper pipe 2, a lower pipe 3, a heating pipe 30, and a control means 40. Further, the control means 40 includes a power supply unit 41,
The controller 42 and the power controller 43 are provided.

Since the hot water storage tank 1, the upper pipe 2 and the lower pipe 3 of the second embodiment are the same as those of the first embodiment, their description will be omitted. Further, the power supply unit 41 is the power supply unit 2 of the first embodiment.
Since it is the same as No. 1, this explanation is also omitted.

The heating pipe 30 is provided with a wax valve 31 and one electric heater 32 as in FIG.

The control unit 42 controls the power control unit 43 on the basis of settings for boiling water. Control unit 42
The energization start time, the energization time, the amount of boiling water, and the like are set as.

The power control section 43 controls the power from the power supply section 41 under the control of the control section 42. That is, the power control unit 43 controls whether to supply less than rated power to the electric heater 32, supply rated power to the electric heater 32, or turn off the electric heater 32.

Next, the operation of the second embodiment will be described.

At the energization start time, as shown in FIG. 5, the control unit 42 supplies less electric power than the rated value to the electric heater 32.
(Step S11), and this state is continued for N minutes (step S12). When step S12 ends, the electric power having the rated capacity is supplied to the electric heater 32 (step S13). Thereafter, the control unit checks whether or not the set amount of hot water has boiled (step S14), and turns off the electric heater 32 when the set amount of hot water has boiled (step S15).
The control for boiling the water ends.

In this way, the control unit 42 supplies less than the rated power to the electric heater 32 for the first N minutes at the time when the energization starts, so that the inside of the heating tube 30 that occurs at the time when the energization starts. You can prevent too much boiling water.

[0036]

As described above, the first invention is
Since two electric heaters are provided in the heating tube and electric power is supplied to only one electric heater at the start of energization, it is possible to prevent excessive boiling of hot water that occurs at the start of energization.

Further, according to the second aspect of the invention, since the electric power supplied to the electric heater is reduced at the start of energization, it is possible to prevent excessive boiling of hot water which occurs at the start of energization.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an example of a heating tube of Example 1.

FIG. 3 is a flowchart illustrating control of a control unit according to the first exemplary embodiment.

FIG. 4 is a schematic diagram showing a second embodiment of the present invention.

FIG. 5 is a flowchart showing control of a control unit according to the second embodiment.

FIG. 6 is a diagram showing a conventional electric water heater.

FIG. 7 is a cross-sectional view of a heating tube of a conventional electric water heater.

FIG. 8 is a diagram showing an example of a wax valve.

FIG. 9 is a diagram showing excessive boiling of hot water in a heating pipe.

[Explanation of symbols]

 1 hot water storage tank 2 upper pipe 3 lower pipe 10 heating pipe 10A outlet 20 control means

Claims (3)

[Claims] 1. A hot water storage tank for storing boiled water, a heating pipe having a temperature flow control valve at an upper outlet, which opens when the boiled water reaches a predetermined temperature, a lower portion of the hot water storage tank, and the heating pipe. In an electric water heater comprising a lower pipe connecting a lower part and an upper pipe connecting an outlet of the heating pipe and an upper part of the hot water storage tank, the electric water heater is provided in the heating pipe for boiling the hot water in the heating pipe. Power is supplied to the two electric heaters and one of the electric heaters is de-energized, and power is supplied to the two electric heaters after a predetermined time from the start of energization until a predetermined time. An electric water heater comprising: 2. A hot water storage tank for storing boiled hot water, a heating pipe having a temperature flow control valve at an upper outlet, which opens when the boiled hot water reaches a predetermined temperature, a lower portion of the hot water storage tank, and the heating pipe. An electric water heater comprising a lower pipe connecting a lower part and an upper pipe connecting an outlet of the heating pipe and an upper part of the hot water storage tank, the hot water being provided in the heating pipe and boiling the hot water by supplying a predetermined electric power. An electric heater; and a control means for supplying electric power less than a predetermined electric power to the electric heater only during a predetermined time from the start of energization and for supplying a predetermined electric power to the electric heater after a predetermined time. Electric water heater. 3. The electric water heater according to claim 1, wherein the temperature flow control valve is a wax valve.