JPH02279950A - Hot water storage type electric water heater - Google Patents

Abstract

PURPOSE:To equalize substantially the quantities of hot water fed from separate hot water storage tanks and to utilize effectively the hot water in each hot water storage tank by connecting a plurality of hot water storage tanks in juxtaposition by using first and second connection pipes, and by equalizing substantially fluid resistances of separate channels from a water feeding pipe to a hot water feeding pipe through the separate hot water storage tanks. CONSTITUTION:First and second hot water storage tanks 1 and 2 are equal to each other in terms of the dimension of an inside diameter and the dimension of the height, and first and second connection pipes 3 and 4 are also equal to each other interms of the dimension of an inside diameter and the length. Accordingly, the fluid resistance of a channel A from the outlet of a water feeding pipe 5 to the inlet of a hot water feeding pipe 6 through the hot water storage tank 1 and the connection pipe 4 and the fluid resistance of a channel B from the outlet of the water feeding pipe 5 to the inlet of the hot water feeding pipe 6 through the connection pipe 3 and the hot water storage tank are equal substantially. Even when the two hot water storage tanks are connected in juxtaposition, therefore, the quantities of hot water fed from the separate hot water storage tanks become equal substantially. When the water in the two hot water tanks 1 and 2 is heated to a prescribed temperature by heating electric heaters 7 and 8 by a midnight discount-rate power and hot water is supplied from the hot water feeding pipe 6, water is supplied by the fed quantity from the water feeding pipe 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a hot water storage type electric water heater that is equipped with a plurality of hot water storage tanks and can be installed in a narrow site.

[Prior Art] When increasing the capacity of a hot water storage type electric water heater using one hot water storage tank, the diameter or height of the hot water tank must be increased. However, if the hot water tank is enlarged in this way, it cannot be installed in a place where width and height dimensions are limited. Therefore, as shown in Japanese Utility Model Application No. 63-196047, hot water tanks are divided into multiple units and installed in parallel to provide a relatively large capacity that can be installed even in places with short width and height dimensions. An electric water heater was proposed. In the electric water heater disclosed in this publication, the hot water tanks are connected in series by connecting the hot water supply port of one hot water tank to the water supply port of the other hot water tank through a connecting pipe.

[Problems to be Solved by the Invention] However, when a plurality of hot water tanks are connected in series using connecting pipes, the following problem occurs.

(a) When hot water tanks are connected in series, the piping route becomes long, and in addition, large diameter hot water tanks and small diameter connecting pipes are arranged alternately between the water supply pipes.
A problem arises in which the hot water supply pressure decreases.

(b) The connecting pipe that connects the hot water inlet of one hot water tank and the water inlet of the other hot water tank has an L-shaped bent part at the upper and lower part, and the upper bent part and the water inlet of one hot water tank are connected to each other. If air accumulates between the hot water supply port and the
/cnf), there is a problem that hot water cannot be supplied. In order to prevent this, an air vent valve may be provided near the upper bend of the connecting pipe, but in this case, a problem arises in that the number of parts increases.

An object of the present invention is to provide a hot water storage type electric water heater in which the hot water supply pressure does not decrease even when a plurality of hot water tanks are installed in parallel.

Another object of the present invention is to provide a hot water storage type electric water heater that does not require the use of an air vent valve.

Still another object of the present invention is to provide a hot water storage type electric water heater that can heat the inside of a plurality of hot water tanks using one electric heater and can increase the utilization rate of each hot water storage tank. It is in.

Another object of the present invention is to provide an electric water heater that can easily reheat or instantaneously boil water even when a plurality of hot water tanks are installed in parallel.

[Means for Solving the Problems] The present invention provides a hot water storage type electric water heater comprising a plurality of hot water storage tanks having a water supply port at the bottom and a hot water supply port at the top, and which achieves the above object by the following configuration. achieve.

In the present invention, the water supply ports of the plurality of hot water storage tanks are
are connected to each other through connecting pipes. Further, the hot water supply ports of the plurality of hot water storage tanks are connected to each other via a second connecting pipe.

A water supply pipe is connected to the first connection pipe, and a hot water supply pipe is connected to the second connection pipe. In particular, in the present invention,
The fluid resistance of each flow path from the water supply pipe through each hot water tank to the hot water supply pipe is made almost equal.

Although an electric heater may be placed in each hot water tank to heat up each hot water tank at the same time, an electric heater may be placed in one hot water storage tank or in the first connecting pipe, and Each hot water tank may be filled with hot water by convection of hot water into each hot water storage tank through a pipe. In this case, the inner diameter of the first and second connecting pipes is preferably larger than the inner diameter of the water supply pipe or the hot water supply pipe.

Alternatively, the tank bodies of a plurality of hot water storage tanks may be connected to each other by a third connecting pipe, and an auxiliary electric heater may be provided in the upper convection passage passing through the third connecting pipe.

[Operation of the invention] If a plurality of hot water storage tanks are connected in parallel using the first and second connecting pipes, the water pressure for hot water supply is less likely to decrease than when a plurality of hot water storage tanks are connected in series. Moreover, since there is no need to install a connecting pipe from above to below, there is no possibility that air will accumulate in the connecting pipe and make hot water supply impossible. In particular, in the present invention, since the fluid resistance of each flow path from the water supply pipe to the hot water supply pipe through each hot water storage tank is approximately equal, even when multiple hot water storage tanks are connected in parallel,
The amount of hot water supplied from each hot water storage tank can be made approximately equal, and the hot water in each hot water storage tank can be used effectively.

If an electric heater is placed in one hot water storage tank or in the first connecting pipe, and hot water is caused to convect within each hot water storage tank through the first and second connecting pipes, then all the hot water in each hot water storage tank can be filled with hot water. can be filled with water, increasing the efficiency of tank usage.

In addition, since only one electric heater requires periodic inspection, inspection and electrical wiring become easier. In addition, the processing cost of the hot water storage tank is reduced, and the cost of the electric heater is also reduced, making it possible to significantly reduce the price of the water heater.

Furthermore, if a short convection path is formed above multiple hot water storage tanks using a third connecting pipe and an auxiliary electric heater, even when multiple hot water storage tanks are connected in parallel, reheating or instantaneous heating can be easily performed. You can boil water.

[Example code] FIG. 1 shows a schematic configuration of an embodiment of the present invention.

In the same figure, 1 and 2 are cylindrical first and second hot water storage tanks that are arranged in an upright state in an exterior case (not shown), and these hot water storage tanks 1 and 2 have water supply ports 1a and 2a at the bottom. and hot water supply ports 1b and 2b at the top, respectively. Water supply ports 1a of hot water storage tanks 1 and 2
and 2a are mutually connected by a first connecting pipe 3, and the hot water supply ports 1b and 2b are mutually connected by a second connecting pipe 4. A water supply pipe 5 such as a water pipe is connected to the end of the first connecting pipe 3 located on the first hot water storage tank 1 side, and the end of the second connecting pipe 4 located on the second hot water storage tank 2 side A hot water supply pipe 6 is connected to the section. Electric heaters 7 and 8 are disposed below inside the hot water storage tanks 1 and 2, respectively.

In the above embodiment, the first and second hot water storage tanks 1 and 2 have the same inner diameter and height, and the first and second hot water storage tanks 1 and 2 have the same inner diameter and height.
The connecting pipes 3 and 4 also have the same inner diameter and length. Therefore, the fluid resistance of the flow path A from the outlet of the water supply pipe 5 through the hot water storage tank 1 and the connecting pipe 4 to the inlet of the hot water supply pipe 6, and the fluid resistance of the flow path A from the outlet of the water supply pipe 5 to the connecting pipe 3 and the hot water storage tank 2. The fluid resistance of the flow path B passing through the water supply pipe 6 and reaching the inlet of the hot water supply pipe 6 is approximately equal. Therefore, even when two hot water storage tanks are connected in parallel, the amount of hot water supplied from each hot water storage tank is approximately equal, and the hot water in each hot water storage tank can be used effectively.

In this embodiment, electric heaters 7 and 8 generate heat using late-night electricity to heat the water in both hot water tanks 1 and 2 to a predetermined temperature. When hot water is supplied from the hot water supply pipe 6, water is supplied from the water supply pipe 5 in an amount equal to the amount of hot water supplied.

A second embodiment of the invention is shown in FIG. This embodiment is similar to the embodiment shown in FIG. 1 in that two hot water tanks are connected in parallel, but is different in that one electric heater heats the water in the two hot water tanks. In the embodiment shown in FIG. 1, the electric heaters 7 and 8 in each hot water tank 1 and 2 are simultaneously energized and fired.
It is not possible to heat water below this point. Therefore, it is not possible to achieve 100% utilization of the hot water tank.

Further, when an electric heater is provided in each hot water tank, there is a problem that the processing of the hot water tank becomes troublesome and the processing cost becomes high. Furthermore, as the number of electric heaters increases, maintenance becomes more troublesome, and moreover, extra inspection space is required to inspect the electric heaters provided in each hot water tank.

The embodiment shown in FIG. 2 is intended to improve the above-mentioned drawbacks of the embodiment shown in FIG. A code is given by adding 10 to the code.

In this embodiment, the first hot water tank 11 is not provided with an electric heater, and the inner diameter of the first and second connecting pipes 13 and 14 is set to be smaller than the inner diameter of the water supply pipe 5 and the hot water supply pipe 6. It's a big deal. Specifically, the inner diameter of the connecting pipe is approximately 2.5 times that of the water supply pipe.

Note that the upper portions of the inner wall surfaces of the connecting pipe 14 and the hot water supply pipe 6 are made to coincide with each other (to be flush with each other) to prevent air from forming between the connecting pipe 14 and the hot water supply pipe. Other points are similar to the embodiment shown in FIG. 1, and the fluid resistance of each flow path from the outlet of the water supply pipe 5 to the inlet of the hot water supply pipe 6 is also substantially the same.

In this embodiment, when the electric heater 18 is energized and heated, the heated water begins to convect along the path indicated by the broken line arrow. As a result, the cold water in the first hot water tank 11 flows from the water supply port 11a through the first connecting pipe 13 into the second hot water tank 12 and is heated. According to this embodiment, both hot water storage tanks 11 and 12 can be entirely filled with hot water having a substantially uniform temperature. According to experiments, the water supply temperature is 100
At the time of C, when a 4.4 kW electric heater is heated using late-night electricity for about 7 hours, the water temperature near the water supply port of the first hot water storage tank 11 and the water temperature near the water supply port of the second hot water storage tank 12 are different. The temperature difference from the hot water temperature was about 3 to 4°C. For comparison, as the first and second connecting pipes 13 and 14,
When the same experiment as above was conducted using pipes having the same inner diameter as the water supply pipe 5 and the hot water supply pipe 6, the temperature difference was about 10 to 15°C. From this result, in order to ensure sufficient convection between both hot water storage tanks, it is preferable to increase the inner diameter dimensions of the connecting pipes 13 and 14 as much as possible.

Further, when the electric heater is provided only in one hot water storage tank, the wiring of the electric heater is simple and the cost for the electric heater can be kept low. By the way, even if the wattage doubles, the price of an electric heater will not double. Therefore, according to this embodiment, the price of the electric water heater can be reduced compared to the conventional one.

FIG. 3 shows a modification of the embodiment of FIG. In this embodiment, a reheating function and an instant water boiling function are added to the water heater of the embodiment shown in FIG. 2. In this example,
The tank body of the first hot water storage tank 21 and the tank body of the second hot water storage tank 2 are connected by a third connecting pipe 20.

In this embodiment, the third connecting pipe 20 is installed at a position approximately 1/4 from the top of the tank body, but this installation position can be determined as appropriate. Auxiliary electric heater 1
9 is arranged above the connection position of the third connection pipe 20. If the temperature of the hot water heated by energizing the electric heater 18 using late-night power drops due to a drop in the environmental temperature or the passage of time, or if the hot water is used before the temperature of the hot water in the hot water storage tank has been heated to the desired temperature. In this case, the auxiliary electric heater 19
It is good to turn on the power. When the auxiliary electric heater 19 is energized,
The heated hot water passes through the upper convection flow path indicated by the dashed line shown in the figure.
・) 212 Convection occurs, and hot water heated by the auxiliary electric heater 19 accumulates inside the first and second hot water storage tanks 21 and 22 located above the auxiliary electric heater 19.

Note that when removing loess using only the electric heater 18 without using the auxiliary electric heater 19, convection occurs not only through the second connecting pipe 14 but also through the third connecting pipe 20, but substantially There is no impact.

According to this embodiment, by adding the reheating or instantaneous boiling function, it is even more convenient to use than the second embodiment.

FIG. 4 shows a schematic configuration of another embodiment of the present invention. In this embodiment, hot water storage tanks 31 and 32 are connected in parallel.
An electric heater 38 and an auxiliary electric heater 39 are placed inside the first and second connecting pipes 33 and 34, without providing an electric heater therein. As in the embodiments shown in Figs. 2 and 3, when an electric heater is placed in one hot water storage tank and all the hot water storage tanks are filled with hot water at a predetermined temperature by using convection, Even under good conditions, it is not possible to completely eliminate temperature differences within the hot water storage tank. As in the embodiment shown in FIG. 4, by arranging the electric heater 38 in the first connecting pipe 33, the position of the electric heater can be made easier than in the embodiment shown in FIGS. 2 and 3. Since it can be placed at the bottom, it is possible to almost eliminate the temperature difference between the two hot water storage tanks.In addition, when the electric heater is placed inside the connecting pipe as in this example, the It is preferable that the inner diameters of the connecting tubes 33 and 34 are larger than those of the connecting tubes 13 and 14 used in the embodiment shown in FIG.

Incidentally, in this embodiment, pipes having a larger diameter than the connecting pipes 13 and 14 used in the embodiments of FIGS. 2 and 3 are used. The auxiliary electric heater 39 heats the hot water in the connecting pipe 34 and also increases the temperature of the upper water in the hot water storage tanks 31 and 32, thereby exerting a reheating function.

According to this embodiment, the temperature difference within the hot water storage tank can be further reduced. Furthermore, since no processing is required to install an electric heater inside the hot water storage tank, the cost of the hot water storage tank can be significantly reduced. Another advantage is that it is easy to add an auxiliary electric heater.

Although each of the above-mentioned embodiments includes two hot water storage tanks, it goes without saying that the present invention can also be applied to a case where two or more hot water storage tanks are connected in parallel.

Further, in the embodiment described above, each hot water storage tank and the connecting pipe have the same shape in order to make the fluid resistance of each flow path from the water supply pipe to the hot water supply pipe through each hot water storage tank approximately equal. However, in order to make the fluid resistance of the flow path approximately equal, it is not necessary that each hot water storage tank and connecting pipe have the same shape. For example, if the inner diameter of one hot water storage tank is small, some of the connecting pipes may The fluid resistance of the flow path can be made approximately equal by increasing the thickness of the flow path.

[Effects of the Invention] According to the present invention, since a plurality of hot water storage tanks are connected in parallel using the first and second connecting pipes, compared to a case where a plurality of hot water storage tanks are connected in series, Since the water pressure for hot water supply does not drop and there is no need to install a connecting pipe from above to below, there is no possibility that air will accumulate in the connecting pipe and make hot water supply impossible. In particular, according to the present invention, since the fluid resistance of each flow path from the water supply pipe to the hot water supply pipe through each hot water storage tank is made approximately equal, even when multiple hot water storage tanks are connected in parallel, each hot water storage tank The amount of hot water supplied from each tank can be made almost equal, and the hot water in each hot water storage tank can be used effectively.

In addition, if an electric heater is placed in one hot water storage tank or in the first connecting pipe, and the hot water is caused to convect within each hot water storage tank through the first and second connecting pipes, all the hot water in each hot water storage tank can be heated. It can be filled with hot water, increasing the efficiency of tank usage.

Furthermore, by using the third connecting pipe and the auxiliary electric heater, there is an advantage that even when a plurality of hot water storage tanks are used, reheating or instantaneous boiling of water can be easily performed.

[Brief explanation of drawings]

FIG. 1 shows a schematic structure of one embodiment of the present invention, and FIGS. 2 to 4 each show a schematic structure of other embodiments of the present invention.

Claims (5)

[Claims] (1) In a hot water storage type electric water heater comprising a plurality of hot water storage tanks arranged in parallel, each having a water supply port at the bottom and a hot water supply port at the top, the water supply ports of the plurality of hot water storage tanks are connected to each other through a first connecting pipe. The hot water supply ports of the plurality of hot water storage tanks are connected to each other via a second connecting pipe, and a water supply pipe is connected to the first connecting pipe, and the hot water supply ports of the plurality of hot water storage tanks are connected to each other via a second connecting pipe, A hot water storage type electric water heater is characterized in that a hot water supply pipe is connected to the connecting pipe, and the fluid resistance of each flow path from the water supply pipe through each hot water storage tank to the hot water supply pipe is approximately equal. (2) The hot water storage type electric water heater according to claim 1, wherein an electric heater is arranged in one of the hot water storage tanks. (3) The hot water storage type electric water heater according to claim 1, wherein an electric heater is disposed within the first connecting pipe. (4) The hot water storage type electric water heater according to claim 2 or 3, wherein the inner diameter of the first and second connecting pipes is larger than the inner diameter of the water supply pipe or the hot water supply pipe. (5) The tank bodies of the plurality of hot water storage tanks are connected to each other by a third connecting pipe, and an auxiliary electric heater is provided in an upper convection passage passing through the third connecting pipe.
, 2, 3 or 4.