JPS5833051A - Controlling device of water heater - Google Patents

Abstract

PURPOSE:To stabilize the temperature of feed hot water by a method wherein the quantity of feed water is controled in proportion to the output of a temperature controler which is adopted to control the amount of heat supply on the base of the difference between the temperature of the feed hot water and a set temperature. CONSTITUTION:The signal from a detector 4 for detecting the temperature of hot water from a heat exchanger 2 is transmitted to the temperature controler 3 and a water controler 7 and the signal is compared to the set temperature signal from a temperature setting device 5 to thereby obtain the difference between the temperature of hot water and the set temperature. Then the output of the temperature controler 3 is transmitted to a heat controler 6 so as to control the amount of heat supplied to the boiler 1 and at the same time, it is transmitted to the water controler 7. When starting the water heater, the flow rate of feed water is made maximum and once the temperature of hot water has been controled constant and in that condition, when the amount of heat supply reaches a maximum and the above mentioned temperature difference becomes higher than a predetermined value, the water controler 7 operates a feed water controler 8 so that the quantity of feed water Fw is controled to make the temperature difference zero. In this case, the duration of the driving time (t) for the control device 8 corresponding to the quantity of feed water Fw is operated in accordance with the attached characteristic graph.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to hot water outlet temperature control for a water heater using gas, oil, electricity, etc. as a heat source. - The purpose of the present invention is to provide a new control device that eliminates the drawback of conventional installations such as not being able to obtain the desired hot water temperature.

□Hereinafter, a gas water heater will be explained as an example.

FIG. 6 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. A signal TWO from the hot water temperature detector 4 and a signal TWR from the temperature setting device 5 are input to the temperature controller 3.
A predetermined combustion amount is determined from the difference TER between and TWR, and a control signal is output to the supply heat amount controller 6 to control the amount of hot water dispensed. Here, for example, a thermistor is often used as the tap water angle detector 4, and a P'iD controller or the like is often used as the temperature controller 3.

FIG. 4 is a diagram showing the relationship between the hot water output amount Fw of the gas water heater and the temperature rise ΔT. The solid line represents the characteristics at maximum combustion amount.
are doing. In other words, the maximum combustion amount Qgmax, temperature rise ΔT, and flow rate Fw are as follows, where η is the combustion efficiency, W'' Qglnax = FwaΔ7 −*
-*-(113 -.

It's next to Vane. Therefore, there are no four temperature rises greater than that shown by the solid line. For example, if the amount of hot water discharged is Fwj when the maximum combustion amount Qgmax is reached, the temperature rise will be ΔT1 as shown in the figure. The temperature controller 3 described above operates effectively when the temperature rise is ΔT1=ΔT1 and the hot water output amount Fw is equal to or less than Fwj. If Fw)F W 1 cannot be controlled, the hot water temperature TWO cannot reach the set temperature.

In this way, the amount of hot water Fw that can be controlled by the maximum combustion amount Qgmax IfC and the hot water temperature is limited.

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, and is capable of always obtaining a hot water outlet temperature TWO that is equal to the set temperature TWR.

FIG. 1 is a block diagram of a gas water heater according to the present invention.

JP-A-58-330511 (2) Items with the same numbers as in FIG. 6 are devices having the same functions. The water flow controller 7 receives a signal T from the hot water temperature detector 4.
It inputs WO, the signal TWR from the temperature setting device 5, and the output of the temperature controller 3, outputs a signal depending on the difference TER between the aforementioned signals TWO and TWR for a predetermined period of time, and controls the water supply amount control device 8. do. When starting to use the gas water heater, the water supply amount control device 8 is initialized so that the maximum flow rate Fwmai is obtained, and when the water temperature control reaches a steady state, the amount of heat supplied to the water heater reaches the maximum value. Furthermore, when the temperature deviation TER is equal to or greater than a predetermined value, the supplied water amount control device 8 is operated to reduce the supplied water amount in accordance with the TEH, and the water amount is controlled so that the TER approaches zero. The point at which the hot water temperature control reaches a steady state is a particularly important issue in systems with large process delays, and can be determined using a timer element. In addition, in a steady state, if the amount of heat supplied is not the maximum and the amount of water supplied is not Fwmax, the water supply amount control device 8 is operated to increase the amount of water supplied, and the set hot water temperature is obtained at the maximum flow rate by operation at the hot water supply point. Rare 5,.

／＜-n so that

FIG. 2 shows the driving means of the water flow control device 8 of the present invention. The horizontal axis represents the output time and the vertical axis represents the flow rate, and it can be seen that the flow rate changes in proportion to the driving time. In other words, within the flow rate change range Fwmax-Fwmin, if the output is made for a certain predetermined time, the same change in flow rate Δ will occur regardless of the flow rate.
Fw is obtained.

Thereby, it is only necessary to calculate the flow rate to be throttled from the deviation TER during steady state according to the capacity characteristics shown in FIG. 4, and to drive the water amount control device 8 for a predetermined time determined from the result.

Although the case where the output time and the flow rate change are in a proportional relationship is shown here, it is of course possible to select the output time accordingly if there is a fixed relationship, even if it is not a proportional relationship.

FIG. 3 shows a specific example of the present invention. Here, an example is given in which the microcomputer 9 is used for various calculations and sequence control, and in particular, water flow control, which is the center of the present invention, is specifically described. 4°! 5, 6.8, as described above, indicate a hot water temperature sensor, a thermistor 6., -, a temperature setting device, a supply heat amount controller, and a supply water amount control device.

First, the acquisition of the deviation TER will be explained. Set temperature TER
is input to the operational amplifier 12 via the resistor 11 as a partial voltage vTER between the variable resistor of the temperature setting device 6 and the resistor 10 connected in series. Furthermore, the hot water temperature TWO is
The partial voltage v between the thermistor 4 and the resistor 13 connected in series
As TWO, the above-mentioned operational amplifier 12 is connected via the resistor 14.
The same TWR potential is applied to the human power section. This operational amplifier 12 forms a so-called adder, the reference potential of which is determined by the voltage division of resistors 15 and 1e, and the difference between "rwo and vTWH" appears as an output due to the resistor 17 that determines the amplification factor, which is used for comparison at the next stage. This is the inverting input of the comparator 18. This comparator 18 receives the value of TEH, that is, the voltage converted vT.
The ER is converted into AM and used as the input P1 of the microcomputer 9 mentioned above, and the reference input side is the output of the D/A converter 19 controlled by the microcomputer output section P2. In this way, the microcomputer receives and processes the deviation ER.

In this example, the output to the supply heat amount control device calculated from the above-mentioned deviation TER according to the PiDi control calculation method is output from the D/A converter 19 to the analog switch 2.
The heat is transmitted to the supply heat amount controller 6 via the drive unit 21 and the drive unit 21 . The analog switch 2o controlled by the microcomputer output P3 is provided to share the D/A converter for input and output.

Furthermore, in the water flow control of the present invention, the supplied water flow control device is driven for a predetermined time calculated from the TER. The transistor 24 is turned on via the transistor 23, the relay Ry1 of the relay 25 is driven, and the relay contact 27 is made conductive in order to energize the motor coil 26 that controls the flow rate in the direction of restriction. The rotation angle of the motor is determined by this conduction time, and the supplied water amount control device 8 is driven via a mechanism section 28 such as a transmission. The combination of 28 and 8 is provided, for example, to obtain the characteristics shown in FIG. When the flow rate is increased by the same operating means, the motor coil 33 is
In order to energize, the relay contact 34 is closed. A portion 35 surrounded by a thin line in this figure includes the temperature controller 3 and the water amount controller 7.

As described above, according to the water heater control device of the present invention, the amount of hot water Fw is always limited to a range where the hot water temperature can be controlled, so an excellent effect can be obtained in that hot water at a desired temperature can be obtained at any time. Furthermore, the output signal to the water supply amount control device can be controlled simply by time management.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a control device for a gas water heater showing an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between output time and flow rate change showing the driving means of the present invention, and FIG. A circuit diagram of one embodiment, FIG. 4 is a characteristic diagram showing the relationship between hot water output amount and temperature rise of a gas water heater, and FIG. 6 is a configuration diagram of a conventional gas water heater. 3... Temperature controller, 4. Fist... Output hot water temperature detector, page 9 6... Temperature setting device, 6... Heat supply controller, 7. ...Water flow rate controller, 8o/0 supply water flow rate control device. Name of agent: Patent attorney Toshio Nakao and 1 other person
Figure Ia2

Claims (1)

[Claims] (1) Water heater outlet temperature detector, temperature setting device,
a temperature controller that outputs a signal for controlling the amount of heat supplied to the water heater depending on a deviation (TER) between a signal of the hot water temperature detector and a signal of the temperature setter; and a temperature controller that is responsive to the output of the temperature controller. The supply heat amount controller of the water heater and the temperature deviation (
a water flow rate controller that outputs a signal for a predetermined period of time to control the water supply amount depending on the amount of water supplied (TER); and a water supply amount control device that controls the amount of water supplied to the water heater in response to the output of the water flow controller. Water heater control device. (21 Claim 1, which is provided with a water supply amount control device that controls the amount of water supplied in proportion to the output time of the water amount controller.
A water heater control device as described in Section 1.