JPS6222382B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to hot water temperature control for water heaters using gas, oil, electricity, or the like as a heat source.

First, a conventional example will be explained using a gas water heater as an example.

FIG. 1 is a block diagram of a conventional gas water heater, in which combustion heat in a burner 1 and water are exchanged in a heat exchanger 2 to provide hot water. The temperature controller 3 receives the signal TWO from the hot water temperature detector 4 and the signal from the temperature setting device 5.
TWR is input, a predetermined combustion amount is determined from the difference between TWO and TWR, and a control signal is output to the supply heat amount controller 6 to control the hot water temperature. 7 indicates a hot water supply location. Here, the hot water temperature detector 4 may be a thermistor, and the temperature controller 3 may be a thermistor.
PiD controllers etc. are often used.

FIG. 2 is a diagram showing the relationship between the hot water output amount Q _L of the gas water heater and the temperature rise ΔT. The solid line represents the characteristics at the maximum combustion amount. i.e. maximum combustion amount
Qgmax, temperature rise ΔT, and flow rate Q _L are as follows, where η is the combustion efficiency, η・Qgmax=Q _L・ΔT ...(1), and ΔT=η・Qgmax/Q _L ...(2) be. Therefore, the temperature rise Δ above that indicated by the solid line
T does not exist. For example, when the maximum combustion amount is Qgmax and the hot water output is Q _L1 , the temperature rise ΔT becomes ΔT ₁ as shown in the figure. The temperature controller 3 described above operates effectively when the temperature rise is ΔT=ΔT ₁ and the hot water output Q _L is equal to or less than Q _L1 . If Q _L > Q _L1 , control becomes impossible and the hot water temperature TWO
cannot reach the set temperature TWR.

In this way, the maximum combustion amount Qgmax limits the amount of hot water Q _L that can control the hot water temperature. This phenomenon is not limited to gas water heaters, but also applies to water heaters using other fuels.

The present invention provides a hot water temperature control device that eliminates the drawbacks seen in the hot water temperature control of the conventional water heater described above.
This allows TWO to be obtained.

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

FIG. 3 is a block diagram of the gas water heater of the present invention.
In the first water flow controller 8, the signal from the inlet water temperature detector 9 is
Input TWi and the signal TWR of the temperature setting device 5, and from the signal difference ΔT _R =TWR−TWi, the maximum combustion amount ΔT = ΔT based on the characteristics shown in Fig. 2 above.
A control signal S ₁ is output to the water supply amount control device 10 so as to reduce the amount of water supply to a flow rate Q _R that is equal to _R. Further, the second water flow rate controller 11 inputs the signal TWR from the temperature setting device 5 and the signal TWO from the hot water temperature detector 4, and outputs a signal _S2 for operating the supply water flow rate control device 10 according to the difference between these signals. Output. The output selector 12 inputs the signals _S1 and _S2 , and selects the water heater according to the signal _S1 from the first water flow controller 8 for a certain period of time from when the water heater starts to be used or from when the set temperature changes. After the predetermined period of time has elapsed, the device 10 is controlled by the signal _S2 from the second water flow controller 11. Components with the same numbers as those in FIG. 1 are devices having the same functions.

When starting to use the gas water heater, the supply water flow control device 10 is initially set to obtain the maximum flow rate Q _L max, and the hot water temperature can be roughly controlled from the TWR and TWi obtained as data at the same time as the start of use. The amount of hot water Q _L is quickly limited to a certain range, and then the second water amount controller 11 performs fine adjustment. Switching to the output signal of the second water flow rate controller 11 is performed using a timer that takes this response time into consideration, since it takes a certain amount of time for the output of the temperature controller 3 to appear as the outlet hot water temperature TWO, especially in a process with a slow response speed. This is done after some time has elapsed.

Describing the function of the second water flow rate controller 11 in more detail here, if the set temperature rise is ΔT ₁ and the hot water output amount Q _L exceeds Q _L1 as shown in FIG. 2, the temperature rise ΔT will be greater than ΔT ₁ . will also become smaller. As a result, the second water amount controller 11 outputs a close signal to the supply water amount control device 10 to throttle the amount of water. If the water volume is throttled and the hot water output reaches Q _L1 , the temperature rise ΔT will be Δ
It becomes equal to T ₁ and the second water flow controller 11 no longer outputs a closing signal. Conversely, if the amount of hot water drawn is less than Q _L1 , the set temperature can be obtained even if the combustion amount is not at its maximum. At this time, the second water amount controller 11 is finely adjusted to increase the amount of water. This takes into account flow rate fluctuations due to water pressure fluctuations, etc., and includes coarse adjustment by the first water flow controller 8 and second water flow controller 11.
The configuration is fine-tuned by

FIG. 4a shows the hot water temperature characteristics of the gas water heater of the present invention, and FIG. 4b shows the hot water output control characteristics. Each horizontal axis represents the elapsed time t, and shows the case where it starts at t=0. As shown in b,
The amount of hot water at the maximum flow rate Q _L max at the start is throttled down to Q _L2 by the first water flow controller 8, and at t= _t3 when the timer time determined by the output selector 12 has elapsed, the output of the second water flow controller is activated. The hot water output is limited to Q _L3 . As can be seen from a, at t= _t3 , T= _T2 , and it can be seen that there is a difference from the set temperature TWR. This is caused not only by water pressure fluctuations as described above, but also by variations in the supply water amount control device between water heaters. Therefore, fine adjustment of the second water flow rate controller 11 is effective.

In addition, the capacity curve shown in Figure 2 differs depending on the size of the water heater, so if you input the size setting signal to the first and second water flow controllers 10 and 11, it will correspond to the water heater of each size. It is possible.

As described above, according to the water heater control device of the present invention, the amount of hot water Q _L is always limited to a range where the hot water temperature can be controlled, so there is an effect that hot water at a desired set temperature can be obtained, and The coarse and fine adjustment functions allow quick control of hot water output, and can also absorb fluctuations in water pressure and equipment.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a conventional gas water heater, FIG. 2 is a diagram showing the relationship between the amount of hot water output and temperature rise of the gas water heater of FIG. 1, and FIG. The configuration diagram of the water heater, FIGS. 4a and 4b, are response characteristic diagrams of the hot water temperature and the hot water amount, respectively, by the control device of the present invention. 3... Temperature controller, 4... Hot water temperature detector, 5
... Temperature setting device, 6 ... Supply heat amount controller, 8 ...
First water flow controller, 9...Incoming water temperature detector, 10...
...supply water amount controller, 11...second water amount controller, 1
2...Output selector.

Claims (1)

[Claims] 1. An inlet temperature detector for water flowing into the water heater, a hot water temperature detector for hot water coming out of the water heater, a temperature setting device for the water heater, a signal from the temperature setting device, and a signal from the hot water temperature detector. a temperature controller that outputs a signal to control the amount of heat supplied to the water heater based on the difference between the two; and a temperature controller that outputs a signal to control the amount of heat supplied to the water heater based on the difference between a first water flow rate controller that outputs a signal to control the amount of water supplied to the water heater, and a second water flow rate controller that outputs a signal that controls the amount of water supplied to the water heater in accordance with the difference between the signal from the temperature setting device and the signal from the hot water temperature detector. an output selector that outputs a signal from the first water flow controller and outputs a signal from the second water flow controller after a predetermined period of time has elapsed; and a supply water flow control device that responds to the signal from the output selector. A water heater control device characterized by: