JPS645712Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a water heater that is connected to a cistern or water supply system that is installed in the water supply via a pressure reducing valve to supply hot water at a constant temperature, or a water heater that is installed in the same way and simply maintains a constant temperature. This is a water heater for supplying hot water, especially equipped with an instantaneous heating type heat exchanger and a circulation pump for forced circulation through a reservoir tank for mixing and agitation. The present invention relates to a gas water heater in which a constant hot water temperature is obtained by controlling a control gas valve using a hot water temperature sensing element.

Conventionally, in this type of gas water heater, when a three-stage or four-stage capacity switching system was adopted for the control gas valve, detection delays occurred due to changes in the amount of hot water coming out, the size of the circulating amount, and the thermal time constant of the hot water temperature detection element. Due to the delay in control, although the temperature of the hot water is constant, it fluctuates within a range of about 1 to 3 degrees Celsius due to overshoot and undershoot. Therefore, in order to prevent abnormal hot water temperature such as hunting, it is necessary to widen the width of the reference signal for switching the capacity, and for this reason, the hot water temperature when the required amount of heat is small and large is also 5 to 7. It will differ by degrees Celsius. This tendency is particularly strong when the amount of hot water dispensed is greater than the amount of hot water circulated, or when the amount of hot water dispensed is extremely small, and in severe cases, there was a drawback that it caused problems in use.

The present invention was devised to eliminate the above-mentioned drawbacks, and provides a structure in which hot water and cold water can be efficiently mixed and stirred in a reservoir tank to supply hot water at a constant temperature.

An embodiment of the present invention will be described below with reference to the drawings.

The structure of the embodiment is as shown in FIGS. 1 to 5, and 1 is a gas water heater main body (hereinafter referred to as main body). 2 is an instant heating type heat exchanger, and 3 is a reservoir tank. 4 is the circulation outlet pipe and heat exchanger 2
The outlet of the reservoir tank 3 is connected to the intermediate inlet 5 of the reservoir tank 3. 6 is a circulation inlet pipe that connects the inlet of the heat exchanger 2 and the lower inlet 7 of the reservoir tank 3. Reference numeral 8 denotes a circulation pump installed in the circulation inlet pipe 6. Reference numeral 9 denotes a circulating water flow detector installed in the circulation inlet pipe 6 that communicates the circulation pump 8 and the heat exchanger 2. 10 is a water supply pipe that communicates with a water supply device such as a cistern (not shown), and also connects to the lower inlet 7 of the reservoir tank 3.
or directly to the circulation inlet pipe 6 between the lower inlet 7 and the circulation pump 8. 11 is a main water flow detector installed in the water supply pipe 10. Reference numeral 12 denotes a hot water supply pipe that is connected to a hot water supply port 13 located at the upper center of the reservoir tank 3 and led to the outside of the main body 1. Reference numeral 14 denotes a hot water temperature sensing element, which is provided near the hot water supply port 13. 15 is a burner, and 16 is a gas pipe. A control gas valve 17 is provided in the middle of the gas pipe 16, and is connected to the circulating water flow detector 9, the main water flow detector 11, and the hot water temperature detection element 1.
This is to control the amount of gas using a separate controller (not shown) using the signal No. 4 so that the water temperature is constant. Reference numeral 18 denotes an exhaust pipe that covers the upper part of the heat exchanger 2 and opens to the outside of the main body 1. Further, in one embodiment of the present invention, as shown in FIGS. 2 and 3, the cylindrical reservoir tank 3 is provided with an inlet 5 which is placed eccentrically on the side surface of the cylindrical reservoir tank 3 in a tangential direction as shown in FIG. A lower inlet 7 is provided, and a hot water supply port 13 is provided at the center of the upper part of the reservoir tank 3. Further, the hot water temperature detection element 14 is provided in the upper part of the reservoir tank 3 near the swirling flow path where the hot water flow from the intermediate inlet 5 reaches the hot water supply port 13. In other embodiments shown in FIGS. 6 and 7, the lower inlet 7 is provided eccentrically and offset from the center on the lower surface of the reservoir tank 3, and other aspects are the same as described above.

The operation of this embodiment in the above configuration will be explained. When a faucet (not shown) connected to the hot water supply pipe 12 is opened, water is supplied from the water supply pipe 10, the main water flow detector 11 is operated, the circulation pump 8 is driven by the controller, and the circulating water flow detector 9 is operated. At this time, the hot water supply port 1 of the reservoir tank 3
When the hot water temperature near 3 is lower than the set value, the capacity is set as appropriate depending on the magnitude of the temperature difference between the set hot water temperature and the hot water temperature detection element 14, the control gas valve 17 opens, and the gas is combusted in the burner 15. The circulating water is heated in the heat exchanger 2, and the heated hot water is transferred to the reservoir tank 3.
It mixes with the water inside and stirs, gradually increasing the temperature. As the temperature detected by the hot water temperature detection element 14 rises accordingly, the capacity of the control gas valve 17 is switched to a smaller one, and hot water is dispensed at the set temperature. Now, if the circulation amount is G ₁ and the hot water output amount is G ₂ , then
In the case of G ₁ ≧ G ₂ , the amount of water passing through the water supply pipe 10, that is, the amount of hot water coming out, all passes through the heat exchanger,
A portion of the water is circulated from the lower inlet 7 of the reservoir tank 3 to compensate for the shortage. At this time, the mixing and stirring state of the reservoir tank 3 is as shown in FIG. 4, where the hot water entering from the intermediate inlet 5 is swirled and mixed with the cold water inside, as indicated by the chain line. Also, G ₁
<G ₂ , part of the cold water supplied from the water supply pipe 10 enters the circulation pump 8, and the other part directly enters the reservoir tank 3 from the lower inlet 7, resulting in the state shown in FIG. 5, that is, the intermediate part. Cold water enters from both the inlet 5 and the lower inlet 7 and is mixed and stirred before being discharged. Here, if the capacity of the reservoir tank 3 is relatively large, the range of change in the hot water temperature is small, but it takes time to reach the desired set hot water temperature, which is inconvenient in use. Furthermore, if the capacity of the reservoir tank 3 is small, the temperature rises quickly, and the thermal time constant of the hot water temperature detection element 14 increases overshoot and undershoot, resulting in a wide range of change in the hot water temperature. Therefore, by utilizing swirling flow as in the present invention, mixing and stirring can be further improved, and even if the capacity of the reservoir tank 3 is relatively small, the detection ability of the hot water temperature sensing element 14 can be improved. As in the case of G ₁ ≫ _{G 2} , mixing and agitation is good even when the amount of hot water discharged is small, so uniformity can be obtained even for the hot water above the middle part inlet 5, and changes in the temperature of the hot water discharged can be made small. Approaching stable and constant temperature hot water supply.
Even when G ₁ <G, the uniformity is similarly improved, so the hot water comes out at a constant temperature and is comfortable to use. Note that by providing the hot water supply port 13 on the center, swirling flow is promoted and the effect is increased.

According to the present invention, the lower inlet and the middle inlet of the reservoir tank are provided eccentrically from the center of the reservoir tank, and the hot water supply port is provided at the center of the upper part of the reservoir tank, thereby creating a swirling flow. The flow is promoted, the mixing and agitation of hot water and cold water are efficiently improved, and hot water can be supplied at a constant temperature.The width of change in hot water temperature is reduced, resulting in stable hot water output, and this also improves the standard for capacity switching. The width of the signal can also be narrowed, which also contributes to stable hot water supply. In particular, it is possible to obtain a gas water heater that can stably supply hot water at a constant temperature even when the amount of hot water output is greater than the amount of hot water circulated or when the amount of hot water output is extremely small.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view of a gas water heater showing an embodiment of the present invention, Fig. 2 is a side view of the reservoir tank of the gas water heater, and Fig. 3 is a plan view of the reservoir tank of the gas water heater. FIG. 4 is a perspective view showing the mixing and stirring state of the reservoir tank of a gas water heater showing an embodiment of the present invention; FIG. 5 is a perspective view showing the mixing and stirring state of the reservoir tank of the same gas water heater; The figure is a side view of a reservoir tank of a gas water heater showing another embodiment, and FIG. 7 is a plan view of the same reservoir tank. 3...Reservoir tank, 5...Intermediate inlet,
7...Lower entrance, 13...Hot water inlet.

Claims (1)

[Scope of utility model registration request] In a gas water heater that has a reservoir tank that communicates with an instant heating type heat exchanger and a hot water temperature detection element in this reservoir tank, the lower inlet 7 and middle inlet 5 of the reservoir tank 3 are located from the center line of the reservoir tank 3. A gas water heater characterized in that the hot water supply port 13 is provided eccentrically, and the hot water supply port 13 is provided at a central position above the reservoir tank 3.