JPH0131108B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water temperature control device for a water heater, particularly a gas instantaneous water heater, and provides a water heater that always provides good hot water dispensing characteristics regardless of whether the hot water is initially dispensing or re-dispensing. The purpose is to provide

Hot water dispensing in a gas instantaneous water heater can be divided into a re-dispensing mode, in which the hot water is re-dispensed immediately after the dispensing is stopped, and an initial hot water dispensing (cold water boiling) mode, in which the hot water is dispensed after a long period of discontinuation. In both of the above modes, the temperature of the pipe water after the heat exchanger is different, and the temperature of the pipe water in the re-discharge mode is higher than the temperature in the initial hot-water supply mode. Therefore, it is clear that if heating is performed in the same sequence in both modes, various damage will occur to the hot water tapping characteristics.
For example, in a system that detects running water and supplies a constant amount of gas to the burner, the water boils when the water is re-discharged, so if the amount of gas supplied is reduced, the rise at the time of initial dispensing will be delayed. In addition, even with a proportional control type that varies the gas amount according to the deviation between the hot water tap temperature and the set temperature, it is possible to temporarily increase the gas amount at the beginning of hot water tap so that hot water can be quickly drawn to the set temperature. Sometimes it overshoots, making it impossible to obtain good hot water tapping characteristics.

The present invention aims to solve the above-mentioned problems, and will be specifically explained below based on an embodiment shown in the drawings.

1 is a heat exchanger, and a hot water supply pipe 2 connected to the heat exchanger 1 is connected to a hot water faucet 3 in a kitchen or the like where hot water is dispensed. 4 is a water supply pipe. 5 is a gas burner,
Reference numeral 6 denotes a gas proportional valve interposed in the gas pipe 7 leading to the gas burner 5. The gas proportional valve 6 increases or decreases the valve opening in proportion to the amount of input signal, and variably controls the amount of gas supplied to the gas burner 5. be. 8 is the hot water temperature detector,
9 is a feed water temperature detector, and 10 is a water amount detector.
Reference numeral 11 has a controller, and the controller 11 is used to control the feed water temperature (Tc) from the feed water temperature detector 9, the water feed amount (Q) from the water amount detector 10, and the set temperature (To) from a temperature setting device (not shown) during steady state. The valve 6 is controlled by the combined output of the gas amount (G1) calculated from and the gas amount (G2) calculated by PID calculation of the deviation between the outlet hot water temperature (TH) and the set temperature (To). The controller 11 also monitors the hot water temperature (TH) from the hot water temperature detector 8 even when hot water tap 3 is closed and hot water tap is stopped before hot water tap starts.
and the water supply temperature (Tc) from the water supply temperature detector 9 is sampled, and when hot water starts being tapped,
The comparison means in the controller 11 compares the hot water temperature (TH) before the start and the water supply temperature (TC) which is the reference temperature.
Based on the comparison result, the determination means in the controller 11 determines whether the mode is the initial hot water supply mode or the re-dispense mode, and based on the determination result, the selection means within the controller 11 selects a different sequence, for example, the initial hot water supply mode. In hot water tapping mode, a gas amount larger than the above-mentioned calculated gas amount is given to the gas proportional valve 6 for a certain period of time.

Next, the operation of the above configuration will be explained based on FIG. 2. As long as the power is turned on, the hot water temperature (TH) and the water supply temperature (Tc) are sampled in the controller 11 as described above even when the water is stopped. When the hot water faucet 3 is opened, water flows into the water supply pipe 4, and when the amount of water reaches a predetermined amount (step),
Next, the comparison means determines whether the difference between the outlet hot water temperature (TH) and the water supply temperature (Tc) is higher than or lower than the set temperature, for example, 10°C. (Step) At this time, the determination means determines that if the temperature difference (TH-Tc) is higher than the set temperature, it is the re-dispensing mode (step), and if it is below the set temperature, it is the initial dispensing mode (step).
The selection means performs heating in a sequence corresponding to both modes and starts dispensing hot water. In other words, in the initial hot water tap mode, the calculated gas amount [G1=
(To−Tc)×Q×60/η: G1 is the gas amount (Kcal/
hr), To is the set temperature (℃), Tc is the water supply temperature (℃),
where Q is the water supply amount (/min) and η is the efficiency], an output with an increased gas amount in proportion to the water supply amount (Q) is output to the gas proportional valve 6 for a certain period of time, and in the case of re-dispensing hot water mode, the amount is not increased. The output of the calculated gas amount (G1) is outputted to the gas proportional valve 6.

Therefore, according to the above example, the gas burner 5 at the beginning of hot water supply
The amount of gas supplied to the water heater is reduced during re-dispensing compared to the initial dispensing, which prevents overshoot and boiling during re-dispensing, resulting in a water boiler with extremely good rising characteristics and excellent dispensing characteristics. It is possible to provide equipment.

Furthermore, in this embodiment, the amount of gas supplied to the gas burner 5 at the start of hot water tap is variably controlled according to the hot water tap mode, but the present invention is not limited to this example. The heating operation may be kept on standby for a certain period of time when hot water is dispensed, and even with this configuration, the problem of boiling when hot water is re-dispensed can be solved in the conventional example.

Further, in this embodiment, the water supply temperature is used as the reference temperature to be compared with the hot water temperature, but a set temperature or a uniquely set fixed temperature may be used as the reference temperature in addition to the water supply temperature.

As explained above, the present invention includes a water supply pipe that has a heat exchanger in the middle, a hot water supply pipe, a burner that heats the heat exchanger, a hot water temperature detector provided in the hot water supply pipe, and a hot water temperature detector that detects the hot water temperature before starting hot water dispensing. A controller comprising a comparison means for comparing the temperature with a reference temperature, a determination means for determining whether it is an initial hot water supply mode or a re-dispensing mode based on the comparison result, and a selection means for selecting a different sequence according to the determination result. Since the burner is controlled, it is possible to perform optimal heating depending on whether hot water is re-discharged or initial hot water, and therefore a water heater with very good hot-water discharging characteristics can be provided.

[Brief explanation of drawings]

FIG. 1 is a control system diagram of a water heater showing an embodiment of the present invention, and FIG. 2 is a control flowchart of the water heater. 1... Heat exchanger, 2... Hot water pipe, 4... Water supply pipe, 5... Burner, 8... Hot water temperature detector, 11
...Controller.

Claims (1)

[Claims] 1 Water supply pipes and hot water supply pipes with heat exchangers in the middle,
A burner that heats the heat exchanger, a hot water temperature detector installed in the hot water supply pipe, and a comparison means that compares the hot water temperature before the start of hot water tap with a reference temperature. Based on the comparison result, it is determined whether it is the initial hot water tap mode or the re-hot water tap mode. 1. A water heater comprising a controller comprising a determining means for determining a sequence, and a selecting means for selecting a different sequence based on the determination result, and a burner is controlled by the controller.