JP2003065600A - Electric water heater water heater - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To minimize the heat loss of an electric water heater without unnecessarily heating hot water in a bathtub B. SOLUTION: A mixing valve 11 for filling water and a circulation system 20 for circulating hot water in a bathtub B through a pump 21 to a heat exchanger 23 in an electric water heater are provided, and the circulation system 20 is provided on a return side. A temperature sensor 26 is provided, and a bypass line 20a with a switching valve 22 for selecting use or non-use of the heat exchanger 23 is provided. The circulation system 20 is used to check the temperature of hot water required during the heat-retaining operation or to prevent the freezing of the pipeline from being performed by the heat exchanger 23.
, The hot water in the bathtub B can be circulated through the switching valve 22 and the bypass pipe line 20a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply device for an electric water heater, which can minimize the heat loss of the electric water heater without heating the hot water in the bathtub unnecessarily.

[0002]

2. Description of the Related Art An electric water heater may be combined with a hot water supply device having a reheating function (for example, Japanese Patent Laid-Open No. H11 (1999) -111945).
-83156 publication).

The hot water supply apparatus is constructed by combining a mixing valve Va for filling water with a circulation system 2 having a pump P and a heat exchanger R (FIG. 9). In addition to the heaters H and H, a heat exchanger R is incorporated in the tank T of the electric water heater, and the outlet side of the mixing valve Va for filling water is connected to the circulation system 2 via the on-off valve Vb. It is connected to the outgoing side.

Therefore, in this device, when the opening / closing valve Vb is opened, the hot water from the tank T and the water from the water source W can be mixed and filled in the bath B through the mixing valve Va. On the other hand, the circulation system 2 can drive the hot water in the bathtub B into the heat exchanger R by operating the pump P, reheat the hot water in the bathtub B via the heat exchanger R, and keep the heat. It is possible to prevent the pipeline from freezing. In addition, in order to determine whether or not additional heating is required during heat retention, it is assumed that the pump P is intermittently operated and the hot water in the bathtub B is circulated in the circulation system 2 to obtain the temperature detected by the temperature sensor TS.

[0005]

According to the prior art, the circulation system operates the pump to circulate the hot water in the bathtub to the heat exchanger of the circulation system when determining whether or not the additional heating is required. Therefore, the hot water in the bathtub may be unnecessarily heated to make the bather feel uncomfortable, and a heat exchanger is also used to prevent freezing of the pipeline, resulting in a large heat loss and extremely uneconomical. There was a problem that was.

Therefore, in view of the problems of the prior art, an object of the present invention is to unnecessarily heat hot water in a bathtub by providing a bypass conduit with a switching valve for selecting use or nonuse of a heat exchanger. It is an object of the present invention to provide a hot water supply device for an electric water heater that can minimize heat loss of the electric water heater without doing so.

[0007]

The structure of the present invention for achieving the above object is a circulation valve for circulating hot water in a bathtub to a heat exchanger in an electric water heater through a mixing valve for filling water and a pump. The circulation system is provided with a temperature sensor on the return side and has a bypass pipe line with a switching valve for selecting use or nonuse of the heat exchanger.

The switching valve may be a heat exchanger or a three-way switching valve provided upstream of the bypass line.

Further, the outlet side of the mixing valve can be connected to the forward side of the circulation system.

Further, the pump may be of a reverse flow type which is provided on the return side of the circulation system, and a water level sensor may be provided on the return side of the circulation system.

[0011]

According to the structure of the invention, the heat exchanger in the electric water heater is used for checking the hot water temperature in order to determine the necessity of additional heating during the heat retention operation and during the freeze prevention operation of the pipeline. In the above, it is possible to select not to use it via the switching valve, to circulate the hot water in the bathtub via the bypass line, and to select it for use in the reheating operation including reheating during the heat retention operation, The hot water can be heated. On the other hand, the mixing valve can mix hot water from the electric water heater with water from a water source such as tap water to fill the bath with an appropriate temperature of hot water.

The switching valve is a three-way switching valve,
Cost can be reduced by minimizing the number of parts.
However, the switching valve may be a combination of two on-off valves.

If the outlet side of the mixing valve is connected to the forward side of the circulation system, the bath can be filled with water via the forward side of the circulation system, and only the forward side and the return side of the circulation system are opened in the bath. However, it is not necessary to provide an opening for filling water in the bathtub.

If the pump is designed to be capable of reverse flow, it is possible to fill hot water from the mixing valve into the bathtub by using both forward and return systems of the circulation system.

If a water level sensor is provided on the return side of the circulation system, the water level sensor can monitor the water level of the hot water in the bathtub and effectively prevent the hot water from overflowing from the bathtub when the water is filled. it can. However, in this case, in order to avoid malfunction of the water level sensor, only the upstream side of the circulation system should be used for the filling, and the switching valve should close both the heat exchanger side and the bypass line side at the same time. I shall.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

The water heater of the electric water heater comprises a mixing valve 11 for filling water and a circulation system 20 (FIG. 1).

In the tank T of the electric water heater, a heater H,
H, heat exchanger 23 is incorporated. A water supply pipe T1 from a water source W is connected to a lower portion of the tank T via a pressure reducing valve Vp, and a hot water supply pipe T2 at an upper portion of the tank T has a relief valve Vr, a mixing valve 11 for filling water, and the like. A mixing valve 31 for external hot water supply is branched and connected. Also, the mixing valve 11,
The outlet side of the pressure reducing valve Vp is connected to each 31. The outlet side of the mixing valve 11 has an opening / closing valve 12 and a flow sensor 1.
3, the downstream side of the heat exchanger 23, that is, the circulation system 2
It is connected to the forward side of 0. The outlet side of the mixing valve 31 is
The temperature sensor 33 is provided on the outlet side of the flow sensor 32, which is connected to an external water faucet (not shown) via the flow sensor 32.

The circulation system 20 includes a back flow type pump 21 provided on the return side from the circulation fitting B1 of the bathtub B, a bypass line 20a with a switching valve 22 provided on the outlet side of the pump 21, and an electric hot water. And a heat exchanger 23 in the tank T of the container. On the suction side of the pump 21, the water level sensor 2
4, a temperature sensor 26 is provided, and a flow switch 25 is interposed between the pump 21 and the switching valve 22. The switching valve 22 includes a heat exchanger 23 and a bypass line 20a.
Is a three-way switching valve disposed on the upstream side of the heat exchanger 23, and the downstream side of the heat exchanger 23 joins the outlet side of the mixing valve 11 and the downstream side of the bypass pipe 20a in this order, and serves as the upstream side of the circulation system 20 as a bath B. It is connected to the circulating metal fitting B1. However, the temperature sensor 14 is provided between the confluence point on the downstream side of the heat exchanger 23, the outlet side of the mixing valve 11, and the confluence point on the downstream side of the bypass conduit 20a.

The switching valve 22 has, for example, an opening 22 on its peripheral surface.
The valve body 22b forming c is incorporated in the housing 22a (FIG. 2). However, FIG.
(D) is an operation explanatory diagram corresponding to the arrow along line XX in FIG. The housing 22a is formed with an inlet side port 22a1 and an outlet side port 22a2, 22a3, and the valve body 22b is provided with a port 22a1, 22a2.
, 22a3 are rotatably incorporated in the confluent portion. The valve body 22b is connected to a drive motor 22d mounted on the housing 22a, for example, a DC motor type or a step motor type.

The switching valve 22 rotates the valve body 22b in the forward and reverse directions via the drive motor 22d, thereby opening the opening 22.
The ports 22a2 and 22a3 on the outlet side can be selectively opened and closed via c. That is, the valve body 22b has the ports 22a2, 22a3 on the outlet side through the opening 22c.
One of the ports is connected to the port 22a1 on the inlet side and the other is closed ((B) and (C) in the same figure).
Both 2a2 and 22a3 can be closed at the same time ((D) in the same figure). That is, the switching valve 22 is the pump 21.
It is possible to selectively switch the outlet side of the heat exchanger 23 side to the bypass pipe line 20a side and simultaneously close both the heat exchanger 23 side and the bypass pipe line 20a side.

The mixing valve 11 for hot water filling, the on-off valve 12, the pump 21 of the circulation system 20, the switching valve 22, and the mixing valve 31 for external hot water supply are controlled by a common controller (not shown) according to designated operation modes. .

In each of the operation modes of the water filling operation, the addition hot water operation, the priming water operation, and the tap water operation (FIG. 3), the pump P is stopped, and the switching valve 22 opens the bypass conduit 20a side to open the heat exchanger 23. When the valve is not used, the on-off valve 12 opens. That is, the mixing valve 11 mixes the hot water from the electric water heater with the water from the water source W, and can use the forward side and the return side of the circulation system 20 together to fill the bath B with hot water of an appropriate temperature. (Arrows K1 and K1 in the figure). The mixing valve 11 continuously adjusts the mixing ratio of the hot water from the electric water heater and the water from the water source W so that the hot water supply temperature detected by the temperature sensor 14 becomes the set temperature. Is 35 to 45 [deg.] C. for the hot water filling operation and the addition hot water operation, and 10 to 25 [deg.] C. for the priming water operation and the tap water operation. However, the mixing valve 11 may directly supply the water from the water source W to the bath B in the priming operation and the water supplying operation.

At this time, the heat exchanger 23 is selected not to be used, and there is no possibility of inadvertently discharging the high temperature hot water therein, and therefore, an excessive heat load is exerted on the downstream equipment including the pump 21. Never give. The on-off valve 12 is
When the integrated value of the flow rate from the flow rate sensor 13 reaches the set amount, the flow rate sensor 13 is closed, and the water filling operation, the addition hot water operation, the priming operation, and the tap water operation can be automatically ended.

In the water level setting type hot water filling operation, the water level setting type hot water operation, and the hot water operation (FIG. 4), the switching valve 22
Closes both the heat exchanger 23 side and the bypass conduit 20a side, and the on-off valve 12 opens. That is, the mixing valve 11 can mix the hot water from the electric water heater and the water from the water source W to fill the bath B with the hot water (in the direction of arrow K2 in the figure). The set temperature at this time is set to, for example, 35 to 45 ° C. for the filling operation and the adding water operation, and is set to 60 to 80 ° C. for the boiling water operation.

In the circulating system 20 for filling and adding water, the pump 21 is operated intermittently, and when the flow switch 25 detects that the water level in the bathtub B exceeds the circulating metal fitting B1, After that, stop the pump 21,
The water level in the bathtub B is continuously monitored via the water level sensor 24. However, the switching valve 22 is supposed to open to the side of the bypass line 20a only while the pump 21 is operating. When the water level in the bathtub B reaches the set value, the on-off valve 12 is closed to complete the operation of filling water or adding water. In addition, during the boiling water operation, the on-off valve 12 is closed when the flow rate integrated value from the flow rate sensor 13 reaches the set amount.

In the reheating operation including reheating during the heat retention operation (FIG. 5), the switching valve 22 opens the heat exchanger 23 side, selects the heat exchanger 23 for use, and operates the pump 21. That is, the circulation system 20 circulates the hot water in the bathtub B to the heat exchanger 23 via the pump 21 (arrow K3a in FIG.
The hot water in bath B can be reheated. At this time, the temperature sensor 26 checks the hot water temperature of the bathtub B, and when the hot water temperature of the bathtub B reaches the set temperature, the pump P is stopped to end the reheating operation.

In the hot water temperature check for determining the necessity of additional heating during the heat retention operation, the freeze prevention operation of the pipeline, and the circulation check operation for determining whether the water level of the bathtub B exceeds the circulation fitting B1. (FIG. 6), the switching valve 22 opens the bypass pipe 20a side and selects the heat exchanger 23 as not used, operates the pump 21, and removes the hot water in the bath B from the bypass pipe 20a.
(The arrow K4a, K4b direction in the figure). Therefore, the hot water in the bathtub B is not unnecessarily heated during the hot water temperature check required during the heat retention operation or during the freeze prevention operation, and there is no unnecessary heat loss of the electric water heater. Further, in the circulation check operation, it is detected via the flow switch 25 that the water level of the bathtub B exceeds the circulation fitting B1.
Moreover, when additional heating is necessary, the heat retaining operation or the additional heating operation can be directly performed.

On the other hand, the mixing valve 31 for external hot water supply can mix the hot water from the electric water heater with the water from the water source W and supply the hot water to the outside when an external mixing tap not shown is opened. (Fig. 7). At this time, the mixing valve 31 operates so that the hot water supply temperature from the temperature sensor 33 becomes the set temperature when the flow rate sensor 32 detects the start of hot water supply.

In the above description, the flow switch 25
May be provided between the water level sensor 24 and the pump 21. Further, the switching valve 22 may be provided on the downstream side of the heat exchanger 23 and the bypass conduit 20a (FIG. 8). The switching valve 22 is replaced with a three-way switching valve instead of the bypass pipe 20a side,
A combination of two on-off valves provided on the heat exchanger 23 side may be used.

[0031]

As described above, according to the present invention, by providing the bypass pipe with the switching valve in the circulation system for circulating the hot water in the bathtub to the heat exchanger via the pump, the circulation system is When checking the hot water temperature required for the heat retention operation or when freezing the pipes, the heat exchanger is not used and the hot water in the bathtub is not circulated in the heat exchanger, making the hot water in the bathtub unnecessary. There is an excellent effect that the heat loss of the electric water heater can be minimized without heating.

[Brief description of drawings]

[Figure 1] Overall configuration piping system diagram

FIG. 2 is an explanatory diagram of a configuration of a switching valve

[Fig. 3] Operation explanatory diagram (1)

[Fig. 4] Operation explanatory diagram (2)

[Fig. 5] Operation explanatory diagram (3)

FIG. 6 is an operation explanatory diagram (4)

[Fig. 7] Operation explanatory diagram (5)

FIG. 8 is a piping system diagram showing another embodiment.

FIG. 9 is a piping system diagram showing a conventional example.

[Explanation of symbols]

B ... Bathtub 11 ... Mixing valve 20 ... Circulation system 20a ... Bypass line 21 ... Pump 22 ... Switching valve 23 ... Heat exchanger 24 ... Water level sensor 26 ... Temperature sensor

Claims (5)

[Claims] 1. A mixing valve for filling water and a circulation system for circulating hot water in a bathtub to a heat exchanger in an electric water heater via a pump, the circulation system including a temperature sensor on a return side. And a bypass pipe with a switching valve for selecting whether to use the heat exchanger or not, the hot water supply device for an electric water heater. 2. The water heater for an electric water heater according to claim 1, wherein the switching valve is a three-way switching valve provided on the upstream side of the heat exchanger and the bypass pipe line. 3. The water heater for an electric water heater according to claim 1, wherein the outlet side of the mixing valve is connected to the forward side of the circulation system. 4. The hot water supply apparatus for an electric water heater according to claim 3, wherein the pump is of a reverse flow type that is provided on the return side of the circulation system. 5. A water heater for an electric water heater according to claim 1, wherein a water level sensor is provided on the return side of the circulation system.