JPS6050333A - Hot water temperature control device for instanteneous gas water heater - Google Patents

Abstract

PURPOSE:To prevent hot water temperature from being unstabled during a time in which a load of hot water volume is varied by a method wherein a control device is provided with a proportional calculator, differential calculator and integration calculator as well as a calculator for a rate of variation in load. CONSTITUTION:A control unit 8 is composed of a proportional calculator 8a, differential calculator 8b, integration calculator 8c and a calculator 8d for a rate of variation in load. The calculator 8d feeds a hot water temperature sensed by a hot water temperature sensor 9 and a load signal Q to vary or set optionally calculated value of the integration calculator 8c. In case that the load (used volume of hot water) is varied rapidly, a rate of variation in the load is calculated by the calculator 8d to get a variation value of the multiplication so as to judge whether a differential value is higher than a desired value or not and in case that the value is higher than the specified value, the value of integration is varied and set, thereafter the unit is reset to perform a normal proportion, differentiation and integration.

Description

[Detailed Description of the Invention] [Object of the Invention] The present invention relates to a water temperature control device for an instantaneous gas water heater, and its purpose is to control the water temperature when the amount of hot water used changes. To provide a hot water temperature control device (ff/) that can provide stable hot water supply.

A conventional device of this kind will be explained with reference to FIG. -, 6 is a gas supply pipe, and 7 is a gas proportional control valve, which is controlled by a controller 8.The controller 8 adjusts the hot water temperature detected by a hot water temperature sensor 9 installed in the hot water supply side piping 6 to a hot water temperature setting device. The deviation value is detected by comparing it with the hot water temperature set in step 10, and a control signal that reduces this deviation value is calculated to maintain the stability of the device when supplying gas to the burner 5. It is necessary to increase the constant to about 5 to 10 seconds.

However, the rate of change in water temperature in instantaneous gas water heaters is extremely fast (
1 to 3d to 7 seconds), so when the amount of hot water used changes, it is not possible to correct the response delay f'L of the mineral integral calculation using only the proportional and differential calculations of hot water temperature control as described above, and the hot water temperature becomes too high. If the control force is too low and the water temperature is too low, the control pressure becomes large and the water temperature becomes stable. Figure 2 shows an example of this, where the amount of hot water used is 10. t/mil and when this is switched to 51/nli at point A, it shows that there is a period IllE where the hot water temperature is unstable. As described above, the conventional device described above has the disadvantage that the hot water temperature becomes unstable during the Yj1 period when the hot water amount load changes. The object of the present invention is to provide a hot water temperature control device that does not have such drawbacks.

[Structure of the Invention] The hot water temperature control device of the present invention has a water temperature sensor and a water temperature sensor in the water inlet pipe 1+11, and has a hot water temperature sensor in the hot water supply side pipe. The gas proportional control valve to be controlled is set to 1 by the outputs of the water flow sensor, water temperature sensor, and hot water temperature sensor, as well as the hot water temperature setting device. In a configuration in which control is performed by a controller that inputs an fc signal and operates once, the controller is constituted by a proportional calculator, a differential calculator, an fh fraction calculator, and a load change rate calculator. It is characterized by That is, in addition to the proportional, differential, and integral calculations in conventional devices, the device of the present invention detects the load change rate when the load changes, and when the deviation value exceeds a certain value, converts the integral value into the load change rate. Accordingly, for example, if the load change rate is 140 inches, set the integral calculation value to 140 inches just before the load change, and if the load change rate is +40 inches, set the integral calculation value to +40 inches before the load change, and then set the integral calculation value to +40 inches before the load change.・It outputs a control signal through differential and integral calculations.

An embodiment of the invention will be briefly explained with reference to FIGS. 3 and 4. FIG. In FIG. 3, numerals 1 to 10 indicate the same parts as in FIG. 11 is a water flow sensor installed in the water inlet side pipe 2;
12 is the water temperature sensor. The controller 8 includes a proportional operator 8a,
It consists of a vy minute calculator 8h, an integral calculator 8C, and a load change rate calculator 8d. The load change rate calculator 8dfj inputs the hot water temperature signal detected by the hot water temperature sensor 9 and the load signal Q, and arbitrarily changes and sets the calculated value of the integral calculator 8C. In the above configuration, if the load (amount of hot water used) changes suddenly, the calculator 8d calculates the load change rate, calculates the integral change value, determines whether the deviation value is greater than a certain value, and determines whether or not the deviation value is greater than a certain value. In the above case, after changing the integral value, return to normal proportional, differential, and integral operations.

[Effects of the Invention] Since the hot water temperature control device of the present invention has the above configuration and function, as shown in FIG. Periods of unstable water temperature, ie.

It stipulates the settling time (a) for the water temperature. Figure 5 (b)
(c) shows the relationship between the load change rate (r) and the water temperature (difference in water temperature); And about the conventional equipment
This is a graph comparing it. The numbers in the graph are experimentally confirmed data, and the device α of the present invention is different from the conventional device @b.
The hot water temperature (n, ←) and settling time p) are smaller than the hot water temperature control characteristics. It is clear that .

[Brief explanation of drawings]

Fig. 1: A diagram showing a conventional hot water temperature control device, showing changes in hot water temperature due to changes in the amount of hot water used. Fig. 5N: A diagram showing an embodiment of the hot water temperature control device of the present invention. Fig. 4: FIG. 6 is a diagram showing a specific configuration of the controller 8. FIG. 5: A graph comparing the characteristics of the device of the present invention and a conventional device. A diagram defining the settling time β and the load change rate γ, ←) is a graph comparing the hot water temperatures Zn and α, and (c) is a graph comparing the settling time β. 1...Heat exchanger, 2...Water inlet side piping, 6...Hot water supply side piping, 4...Hot water tap, 5...Burner, 6...Gas supply pipe, 7...Gas Proportional control valve, 8...controller,
8α... Proportional calculator, 8h... Differential calculator, 8C.
... Integral calculator, 8d --- Load change rate calculator, 9...
・Water temperature sensor, 10... Hot water temperature setter, 11... Water amount sensor, 12... Water temperature sensor, 13... Controlled circuit Fig. 1 Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Claims] The water inlet side piping has a water amount sensor and a water temperature sensor, and the hot water supply side piping has a water temperature sensor and a waste proportional control valve that controls the amount of fuel to be supplied to the burner that heats the heat exchanger. In a configuration in which the controller operates by inputting the outputs of the sensor and the hot water temperature sensor and the signals set by the hot water temperature setting device, the controller includes a proportional calculator, a differential calculator, an integral calculator, and a load. A water temperature control device for an instantaneous gas water heater, comprising: a rate-of-change calculator;