JPS6149573B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water heater that circulates hot water in a hot water tank using a pump and extracts hot water from a hot water tap.

As shown in FIG. 1, the conventional water heater is equipped with a pump 3 that circulates hot water from the hot water tank on the outflow side of the hot water tank in a hot water circulation closed circuit 2 that passes through the hot water tank 1, and a pump 3 that circulates hot water from the hot water tank at the inlet of the hot water tank. There is one in which a water supply pipe 5 having a stop valve 4 is provided, and hot water is taken out from a hot water tap 6 attached from the pump 3 to the water supply pipe 5. This is because the set hot water is obtained by matching the water temperature in the hot water tank 1 with the hot water temperature taken out from the hot water tap 6, so it takes time to obtain hot water from a high temperature to a low temperature or vice versa, and Since the temperature of tank 1 was not maintained at a high temperature, hot water storage efficiency could not be increased.

On the other hand, those that maintain the water temperature in the hot water tank at a high temperature and increase the storage efficiency, mix the hot water from the hot water tank and the water from the water supply pipes near the hot water tap to maintain an appropriate temperature.
If the temperature were automatically adjusted, each faucet would have to be equipped with a temperature sensor and a mixing valve, which would be expensive and require hot water distribution pipes.Moreover, heat would be dissipated from the hot water circulation closed circuit that circulates hot water. However, there is a problem in that the maintenance costs during operation are also high.

This invention was made in view of the above circumstances, and it improves hot water storage efficiency by keeping the water temperature in the hot water tank at a high temperature, allows hot water to be instantly obtained at any set temperature from the hot water faucet, and also allows piping. The purpose of the present invention is to provide a water heater that has low maintenance costs by reducing the amount of heat released.

The present invention will be described below based on embodiments shown in the accompanying drawings.

FIG. 2 is a diagram showing a first embodiment of the present invention for circulating hot water in a hot water tank with a pump and extracting hot water from a hot water tap.

As shown in FIG. 2, a hot water circulation closed circuit 8 that passes through the hot water tank 1 heated by a burner 7, etc. has a mixing valve 9 that mixes hot water and water from the outflow side 1a to the inflow side 1b of the hot water tank 1. , a circulation pump 3 and a solenoid valve 10 are provided in this order. In addition, a water supply pipe 5 with a check valve 4 installed in the middle is connected to the inflow side 1b of the hot water tap 1 and the mixing valve 9 in order to supply water to the hot water tank 1 and the mixing valve 9. , when the electromagnetic valve 10 is opened and water flows from the electromagnetic valve 10 to the inflow side 1b of the hot water tank 1, it is activated to prevent water from flowing towards the water supply pipe 5.

Temperature detection means 11 for detecting the temperature of the mixed water of hot and cold water is provided on the outflow side of the mixing valve 9, and a pump 3 is provided midway between the mixing valve 9 and the temperature detection means 11.
A circulation path 12 connected to the discharge side of the pump is provided. At least one hot water tap 6 is provided between the temperature detection means 11 and the pump 3.
Also, a check valve 3a is provided on the discharge side of the pump 3 to prevent flow from the discharge side to the suction side of the pump 3.
The check valve 3a allows the hot water from the hot water tank 1 and the water from the water supply pipe 5 to be mixed automatically even when the pump 3 is stopped.

The mixing valve 9 is controlled by a valve control means 13 which receives a signal from a temperature detection means 11 as an input, so that hot water from the hot water tank 1 and water from the water supply pipe 5 are adjusted to a temperature set by a temperature setting device 14. The mixing ratio with water is controlled, and hot water at an appropriate temperature can be obtained from the hot water tap 6.

Next, an example of the mixing valve 9 and its control will be explained based on FIGS. 3 to 5.
As shown in the figure, the valve body 1 is formed into a substantially cylindrical shape.
In the valve body 15, a hot water inlet 16 and a water inlet 17 are provided facing each other on the side wall, and an outlet 18 for the mixed water is provided in the lower end surface. A substantially semi-cylindrical closure 19 that adjusts the inflow amount of hot water and water from the water inlet 17 is rotatably inserted, and the shaft 20 of the closure 19 is sealed and protrudes from the upper end surface of the valve body 15. There is. The closing shaft 20 is rotated by a motor 21 such as a gear motor, and the amount of rotation is detected by a potentiometer 22 that is interlocked with the shaft 20. Note that the closure 19 is connected to the hot water inlet 16 in the state shown in FIG.
If the hot water from the hot water and the water from the water inlet 17 are made to flow out from the outlet 18 almost equally, and if the closure 19 is rotated 45 degrees to the right from the state shown in FIG.
is completely closed, allowing only hot water to flow out from the water outlet 18, and conversely moving the closure 19 to the left from the state shown in Figure 4.
When rotated by .degree., the hot water inlet 16 is completely closed and only water can flow out from the outlet 18.

In addition, as shown in FIG. 5, the power switch 23
When turned on, the circulation pump 3 is driven and the primary side of the transformer 24 is energized. This alternating current voltage generated on the secondary side is converted into a constant voltage direct current by a constant voltage circuit 27 via a rectifier 25 and a smoothing capacitor 26. This constant voltage circuit 27
For the constant voltage, there is a resistor 28, a temperature setting device 14 consisting of a variable resistor for setting the hot water to be supplied,
In order to detect the temperature of the mixed water mixed by the mixing valve 9, a temperature detection means 11 such as a thermistor whose resistance value changes depending on the temperature and a resistor 29 are connected in series in order, and the connection point between the resistor 28 and the temperature setting device 14 is connected in series. The detected voltage V ₀ based on the set temperature and detected temperature is obtained from . A PID control circuit 30 which receives this detection voltage V ₀ and the first reference voltage V ₁ based on the constant voltage as input.
converts the detected voltage V ₀ into a control voltage V ₂ corresponding to it and outputs it. A resistor 31, a potentiometer 22, and a resistor 32 are connected in series to the constant voltage circuit 27, and the potentiometer 22 outputs a rotation voltage proportional to the rotation angle of the closure 19 in the valve body 15.
V ₃ is obtained. The differential voltage V ₄ is output from the differential circuit 33 to which the rotational voltage V ₃ and the control voltage V ₂ are input.
is output, and this differential voltage V ₄ is compared with the first and second comparison voltages E ₁ and E ₂ of the first and second comparison circuits 34 and 35, and the motor 21 rotates the closure 19 and the potentiometer 22. The first to fourth transistors Q 1 to Q 4 that drive and control the transistors Q ₁ to _{Q 4} are controlled.

That is, first, when hot water at the set temperature is obtained, the first and second comparison circuits 34 and 35 both issue low level signals, and the motor 21 is stopped, it is assumed that the detected temperature, which is the water supply temperature, has increased. For example, the resistance value of the temperature detection means 11 decreases, the detection voltage V ₀ decreases, and the differential voltage V ₄ decreases, so that the first comparator circuit 34 maintains a low level signal and the second comparator circuit 35 maintains a high level signal. and the third and fourth transistors Q ₃ , Q ₄
is turned on, and the rotation of the motor 21 is controlled so that the amount of water supplied from the closure 19 is greater than before. As the motor 21 rotates, the potentiometer 22 also rotates, and the rotational voltage V ₃ obtained from the potentiometer 22 decreases, so the differential voltage V ₄ increases and the second comparison circuit 35 returns to a low level. Then,
Motor 21 is stopped from rotating.

Contrary to the above, if the hot water supply temperature, that is, the detected temperature, decreases and the detected temperature V ₀ increases, the differential voltage V ₄ increases, the first comparison circuit 34 becomes high level, and the first and second transistors Q ₁ Q ₂ , the rotation of the motor 21 is controlled so that the amount of hot water supplied from the closure 19 is larger than before, and the rotational voltage V ₃ from the potentiometer 22 increases as the motor 21 rotates. Motor 21 is stopped from rotating.

In addition, by operating the temperature setting device 14, the detected temperature V ₀
It operates in the same way as above when it rises or falls.

The present invention has the above configuration, and its operation will be explained next.

First, the burner 7 is ignited, and the power switch 23 is turned on.
is turned on, the pump 3 is operated, and the temperature setting device 14 is set at an appropriate temperature, for example, 42°C. If hot water is being taken out from the hot water faucet 6 in this state, the solenoid valve 10 remains closed, hot water from the hot water tank 1 and water from the water supply pipe 5 are mixed at the mixing valve 9, and this mixed water is circulated by the pump 3 and further mixed with the hot water that has passed through the circulation path 12 and passed through the temperature detection means 11. A portion of the hot water is discharged from the hot water tap 6, and the rest passes through the circulation path 12 via the pump 3. and then circulated. Note that when the discharge amount from the hot water tap 6 increases or decreases and the temperature of the temperature detection means 11 changes, the mixing valve is controlled by the valve control means 13 which operates in accordance with the temperature change. 9 is controlled to make the mixing ratio of hot water in the hot water tank 1 and water in the water supply pipe 5 appropriate. Note that the solenoid valve 10 will not open when the hot water tap 6 is open.

Next, when all the hot water taps 6 are closed and the use of hot water is stopped, the hot water is circulated by the pump 3 in a closed circuit from the discharge port of the pump 3 through the circulation path 12 and back to the suction port of the pump 3. When the temperature of the temperature detection means 11 becomes lower than the set temperature by a predetermined temperature, for example, 5° C. or more due to heat radiation, the solenoid valve 10 is opened and a portion of the hot water discharged from the pump 3 is diverted to the circulation path 12.
The remaining water is circulated through the hot water tank 1 to the pump 3. Such a cycle takes place,
The temperature of the circulating water rises due to the hot water from the hot water tank 1, and when the temperature reaches the set temperature again, the solenoid valve 10 is closed again, and the hot water discharged from the pump 3 passes only through the circulation path 12 and is supplied to the pump 3. It returns to the suction port. Note that when the solenoid valve 10 is opened, the solenoid valve 1
When a flow occurs from water supply tank 1 to water supply tank 1, the flow also tends to occur in water supply pipe 5, but the check valve 4 in water supply pipe 5 prevents the flow toward water supply pipe 5.

In the above embodiment, although the control device for the solenoid valve 10 is not shown, the solenoid valve 10 is opened when the temperature becomes lower than the set temperature by a predetermined temperature (for example, 5°C) or more, and the solenoid valve 10 is opened when the temperature reaches the set temperature. It may be any control means that controls the opening when the opening is closed. In addition, a solenoid valve that is controlled to open and close in the opposite manner to the solenoid valve 10 is connected to the circulation path 1.
By installing it in the middle of 2, circulation path 1 can be completed in a short time.
The hot water circulating in step 2 may be heated to a high temperature. Further, the temperature detection means 11 may be another temperature sensor such as a thermocouple, and the valve control means 13
is not limited to the circuit diagram shown in FIG. 5, and can be arbitrarily modified without departing from the gist of the valve control of the present invention.

Next, a second embodiment of the present invention will be described with reference to FIGS. 6 to 12.
The explanation will be based on the drawings shown in the figures.

As shown in FIG. 6, the outlet 1a of the hot water tank 1 heated by the burner 7 is connected to the hot water inlet 4 of the four-way valve 9a.
A water supply pipe 5 connected to the hot water supply tank 1 and provided with a check valve 4 in the middle supplies water to the inlet 1b of the hot water tank 1 and the water inlet 41 of the mixing valve 9a. The outflow port 42 of this mixing valve 9a is connected to the suction side of the pump 3, and the discharge port of the pump 3 is connected to the circulating water inlet 43 of the mixing valve 9a. A temperature detection means 11 for detecting the temperature of the mixed water mixed by this valve is installed behind the outlet 42 of the mixing valve 9a, and at least a hot water tap 6 is installed between the mixing valve 9a and the pump 3. One is provided. Also, this second
In the case of this embodiment as well, a check valve 3a is provided on the pump discharge side as in the first embodiment.

As shown in FIGS. 7 to 9, the mixing valve 9a is provided with a hot water inlet 40 and a water inlet 41 facing each other on the side wall of a substantially cylindrical valve main body 44, and a circulating water flow. The inlet 43 is located at a position substantially perpendicular to the water outlets 40 and 41 and is provided below them. In addition, each inlet 40, 41,
An outflow port 42 through which the mixed water flows out from the inlet 43 is provided on the lower end surface of the valve body 44, and a substantially cylindrical closure 45 is provided in the valve body 44 to adjust the amount of inflow from each of the inflow ports 40, 41, and 43. is rotatably inserted, and the shaft 46 of the closure 45 is sealed and protrudes from the upper end surface of the valve body 44. It should be noted that, like the closure 19, this closure 45 is also rotated by the motor 21, and the amount of rotation thereof is detected by a potentiometer 22 that is interlocked with the closure 19. In addition, the mixing valve 9a
The motor 21 is controlled by the valve control means 13a which inputs a signal corresponding to the temperature from the temperature detection means 11.
By controlling the temperature, the temperature is controlled to be the temperature set by the temperature setting device 14, and hot water at an appropriate temperature can be obtained from the hot water tap 6.

A hot water mixing opening 47 for mixing hot water and water is formed in the peripheral wall of the closure 45 in the same horizontal plane as the hot water inlet 40 and the water inlet 41 of the valve body 44, and the hot water A circulating water opening 48 for flowing circulating water is formed below the mixing opening 47 and on the same horizontal plane as the circulating water inlet 43,
These openings 47 and 48 communicate with the inside of the closure 45. Furthermore, an axis-parallel groove 49 is formed in the peripheral wall of the closure 45 near the water inlet 43 for communicating the water inlet 41 and the circulating water inlet 43, and this groove 49 is separated from the inside of the closure 45. Not communicating. Note that the mixed water opening 47 should not be in contact with the circulating water inlet 43, and should not be in contact with the circulating water opening 4.
8 are formed so as not to contact the hot water inlet 40 and the water inlet 41, respectively. Further, the opening angle of the mixed water opening 47 is preferably approximately 180°, but is not limited to this.
Further, the opening angle of the circulating water opening 48 may be any angle as long as the circulating water can be constantly circulated.

In addition, in the state shown in FIGS. 10a and 10b, the closure 45 equalizes the inflow amount of the hot water inlet 40 and the water inlet 41, and causes the circulating water to flow out from the outlet 42 together with the circulating water.
From the state shown in Figure 10 a and b, move the closing member 45 approximately 45 to the right.
When rotated, the water inlet 41 and circulating water inlet 43
only connected to the outlet 42, and FIG. 11a,
In the state of b, only the hot water inlet 40 and the circulating water inlet 43 are connected to the outlet 42, and in addition,
In the state shown in FIGS. 12a and 12b, which are rotated to the left from the state b, the circulating water inlet 43 is connected to the water inlet 41 and the outlet 42, and the hot water outlet 40 is connected to the water outlet 42. In the state shown in FIGS. 12a and 12b, part of the circulating water from the circulating water inlet 43 is fed to the hot water tank 1, and the rest is returned to the outlet 42.

Even in the second embodiment having the above configuration, the motor 21 that rotates the closing member 45 can be controlled by the circuit diagram shown in FIG. in this case,
When the hot water tap 6 is not used or when the burner 7 is ignited, the mixing valve 9a is opened from the discharge port of the pump 3.
If the temperature of the circulating water that is circulated to the suction port of the pump 3 via the temperature detection means 11 is low enough, the closure 45 will be in the state shown in FIG. A portion of the water is returned to the hot water tank 1, the temperature of the circulating water rises rapidly, and the circulating water inlet 43 and water inlet 41 are cut off. Therefore,
In this second embodiment, unlike the first embodiment, there is no need to provide the solenoid valve 10, and there is no need to provide a control means for controlling the solenoid valve 10, so that the configuration is simplified.

Next, a third embodiment of the present invention will be explained based on FIGS. 13 and 14. The only difference between this third embodiment and the second embodiment is the structure of the closure. I will explain only those and omit the others.

As shown in FIG. 13, the closure 45a has an eighth
Similar to the closure 45 shown in the figure, a shaft 46, a mixed water opening 47, and a circulating water opening 48 are provided. An L-shaped groove 49a is formed near the water inlet 43 in the peripheral wall of the closure 45a to communicate the water flow inlet 41 and the circulating water inlet 43. Therefore, as shown in FIG.
When the opening ratio of 1 becomes less than a certain value (for example, 20%), the water inlet 41 and the circulating water inlet 43 are communicated with each other by the groove 49a, and the circulating water from the circulating water inlet 43 passes through the water inlet 41 to supply hot water. It will be fed to tank 1. Unlike the second embodiment, this third embodiment does not block or communicate the circulating water inlet 43 and the water inlet 41 by opening and closing the water inlet 41, and therefore operates more stably than the second embodiment. I can do it.

In addition, in the above embodiment, the pump 3 includes:
An automatic exhaust valve (not shown) is installed to prevent problems such as cavitation in the pump.

As described above, this invention has a hot water temperature of 85℃ in a hot water tank.
Since hot water from the hot water tank and water from the water supply pipes are mixed using a mixing valve, hot water at the set temperature can be obtained instantly, and the circulating water is maintained at a temperature of about 42°C. Because hot water is circulated at a set temperature, the amount of heat radiated from the supply pipes that circulate the hot water is small, reducing operation and maintenance costs.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a conventional water heater, Fig. 2 is a diagram showing an example of the present invention, Fig. 3 is a perspective view showing an example of a mixing valve used in the invention, and Fig. 4 is a diagram showing an example of the mixing valve used in the invention. 3 is a cross-sectional view, FIG. 5 is a circuit diagram showing an example of an automatic temperature control circuit for maintaining the hot water temperature at a set temperature in this invention, FIG. 6 is a diagram showing another example of this invention, and FIG. The figure is a perspective view showing an example of the mixing valve used in Fig. 6, Fig. 8 is a perspective view showing an example of the closure of the mixing valve shown in Fig. 7, and Fig. 9 is a longitudinal sectional view of Fig. 8. , Fig. 10a, Fig. 11a, and Fig. 12a are sectional views taken along the line A--A in Fig. 9, Fig. 10b, and Fig. 11b, showing the relationship between the rotational position of the closure and each inlet. and FIG. 12b are sectional views taken along line B--B in FIG. 9 in the same state as FIGS. 10a, 11a, and 12a, respectively, and FIG. 13 is a sectional view of the mixing valve used in this invention. A perspective view showing an example, and FIGS. 14a and 14b are lines AA and B in FIG. -B
It is a sectional view taken at the same position as the line. 1... Hot water tank, 2, 8... Hot water supply circulation closed circuit, 3... Pump, 3a, 4... Check valve, 5... Water supply pipe, 6... Hot water tap, 7... Burner, 9, 9a... Mixing valve, 10... Solenoid Valve, 11...Temperature detection means, 12...Circulation path, 13,
13a... Valve control means, 14... Temperature setting device, 15...
Valve body, 16, 17...Inlet, 18...Outlet, 1
9... Closer, 20... Shaft, 21... Motor, 22... Potentiometer, 23... Power switch, 24... Transformer, 25... Rectifier, 26... Capacitor, 27...
Constant voltage circuit, 28, 29, 31, 32...resistance, 3
0...PID control circuit, 33...Differential circuit, 34, 35
...Comparison circuit, 40, 41, 43...Inflow port, 42...
Outlet, 44... Valve body, 45, 45a... Closure, 4
6... Axis, 47, 48... Opening, 49, 49a...
groove.

Claims (1)

[Scope of Claims] 1. A hot water tank to which water is supplied from a water supply pipe, a mixing valve capable of controlling the inflow amount of hot water from the hot water tank and water from the water supply pipe, and a water supply tank provided on the outflow side of the mixing valve. and a pump that circulates the mixed water of the mixing valve between the mixing valve and the temperature detection means, and the temperature detected by the temperature detection means is lower than the hot water supply setting temperature by a predetermined temperature or more. A hot water supply device characterized in that at least a part of circulating water discharged from a pump is sent to a hot water tank only when the pump is in use. 2. The mixing valve has a hot water inlet through which hot water from the hot water tank flows in, a water inlet through which water from the water supply pipe flows in, a circulating water inlet through which circulating water from the pump flows in, and an outflow port. It is a two-way valve, and the circulating water inlet and outlet are always in communication, and the inflow of hot water from the hot water inlet and water inlet from the water inlet can be controlled, and only the hot water inlet and the circulating water inlet are communicated with the outlet. 2. The hot water supply device according to claim 1, wherein the circulating water inlet and the water inlet are communicated with each other when the water is being used. 3. The mixing valve has a hot water inlet through which hot water flows from the hot water tank, a water inlet through which water from the water supply pipe flows in, a circulating water outlet through which circulating water from the pump flows in, and an outlet. It is a four-way valve, and the circulating water inlet and outlet are always in communication, and the inflow amount of hot water from the hot water inlet and water from the water inlet can be controlled, and the aperture ratio of the hot water inlet can be kept above a specified level. 2. The water heater according to claim 1, wherein the circulating water inlet and the water inlet are connected to each other.