JPH0612193B2 - Water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is provided by adjusting the supply amount of fuel such as gas.
The present invention relates to a proportional water heater capable of obtaining hot water having a desired set temperature regardless of the amount of hot water supplied.

(Prior Art) The configuration of a water heater is shown in FIG. 1 is the water supply channel in the water heater,
Reference numeral 2 is a water amount sensor provided in the water supply passage for detecting the amount of hot water supply, 3 is a water inlet temperature sensor for detecting the water inlet temperature, 4 is a heat exchange unit, 5 is a hot water outlet temperature sensor for detecting the hot water temperature, and 6 is fuel supply. Fuel passage, 7 is a fuel proportional valve for adjusting the amount of fuel such as gas amount, 8 is a hot water temperature control circuit, 9 is a temperature setting circuit, and the hot water temperature control circuit 8 is hot water at the hot water temperature set by the temperature setting circuit 9. The hot water supply amount obtained by the water amount sensor 2 and the incoming water temperature and the outgoing hot water temperature obtained by the temperature sensors 3 and 5 are arithmetically processed so that the hot water temperature detected by the temperature sensor 5 is promptly matched and stabilized, and the fuel proportional valve 7 is operated. Control the voltage that drives the.

However, in order to perform heat exchange by burning the gas supplied by the fuel proportional valve 7 in the heat exchange part 4, problems occur such as damage of the heat exchange part 4 at the upper limit of the heat exchange amount and stop of gas combustion at the lower limit of the heat exchange amount. . FIG. 2 shows a conventional structure of the temperature control circuit 8 for solving these problems. 11 is a proportional control circuit,
Reference numeral 12 is a voltage limiting circuit, 17 is a semi-fixed resistor for setting the proportional valve drive minimum voltage, and 18 is a half-process resistor for setting the proportional valve drive maximum voltage. The driving voltage V ₁ obtained by the above is set by the semi-fixed resistor 17, the driving voltage V ₂ obtained by the maximum gas amount is set by the semi-solid resistor 18, and the proportional valve driving voltage is set by the voltage limiting circuit 12. to V ₁ was when the output voltage is V ₁ or less proportional control circuit 11, in the case of V ₂ or more to prevent the occurrence of problems in the heat exchange unit by limiting the V _2.

(Problems to be Solved by the Invention) In this conventional method, the maximum and minimum values of the proportional valve drive voltage are actually burned in order to absorb variations in the proportional valve and the heat exchange unit, while monitoring the hot water output. In addition to the work required to set with a semi-solid resistor, the function cannot be maintained unless resetting is performed with respect to the secular change in the proportional valve capacity after setting and the heat exchange efficiency of the heat exchange section.

(Means for Solving Problems) A water heater according to the present invention includes a water supply passage 1, a water amount sensor 2 provided in the water supply passage 1, and a heat exchange unit 4 provided in the water supply passage 1. A temperature sensor 3 attached to each of the water inlet portion and the hot water outlet portion of the heat exchange portion 4 for detecting the water inlet temperature;
A temperature sensor 5 for detecting the outlet heated water temperature, a fuel passage 6 for supplying fuel to the heat exchange section 4, a fuel proportional valve 7 provided in the middle of the fuel passage 6 for adjusting the flow rate of the fuel, and an outlet heated water temperature are set. The temperature setting circuit, the amount of hot water detected by the water amount sensor, the incoming water temperature and the outgoing hot water temperature detected by the temperature sensor, adjust the opening of the fuel proportional valve to obtain the outgoing hot water temperature set by the temperature setting circuit. In a water heater having a hot water temperature control circuit 8 having a control voltage V ₁ for presetting the minimum opening of the fuel proportional valve and a control voltage V ₂ for presetting the maximum opening, the hot water temperature control circuit 8 is provided. The voltages V ₁ and V _{2 in} which the maximum opening and the minimum opening of the fuel proportional valve are preset are the product of the hot water supply amount obtained by the water amount sensor and the difference between the incoming water temperature and the outgoing hot water temperature obtained by the temperature sensor. And set up first Characterized by having a correction circuit for correcting in hot water by comparing the the minimum output Q ₁ and maximum output Q ₂ to which is outputted by the voltage V ₁ and V _2.

FIG. 1 schematically shows the configuration of the tapping temperature control circuit of the present invention. Reference numeral 13 is an output calculation circuit for calculating the actual hot water output of the water heater, 14 is an output limiting circuit for obtaining the maximum and minimum proportional valve drive voltages based on the actual hot water output and the proportional valve drive voltage, 15 is a resistor for setting the minimum hot water supply output, 16 Is a resistor for setting the maximum output of hot water supply, and the output calculation circuit 13 outputs the actual hot water output q by (hot water temperature-water input temperature) x hot water supply amount. Output limiting circuit 14
Is the output voltage Vt of the proportional valve control circuit 11 and the output calculation circuit 1
3 of the output q and minimum output Q ₁ resistor 15 and the maximum output Q ₂ to which to fix the Enter the voltage set by the resistor 16 which fixes, compares the output q, the minimum output Q ₁ and maximum output Q ₂ The voltage limiting circuit 12 corrects the voltages V ₁ and V ₂ initially set by the correction circuit that corrects during hot water supply.
The proportional valve drive minimum voltage V ₁ and the proportional valve drive maximum voltage V ₂ which are input to The output Vt of the proportional control circuit 11 is limited to V ₁ or more and V ₂ or less by the voltage limiting circuit 12 to obtain the proportional valve drive voltage Vl.

(Function) The output limiting circuit 14 the minimum output Q ₁ proportional valve driving voltage V ₂ for maximum output Q ₂ to which is set by the proportional valve driving voltages V ₁ and the resistor 16 for obtaining a set by the resistor 15 The output Vt of the proportional control circuit 11 and the output q obtained by the output calculation circuit 13 can be used for sequential correction.

(Embodiment) FIG. 4 shows an embodiment of the present invention. 21 is a pulse shaper,
22 is a microcomputer, 23 is a D / A converter, 24 is a variable resistor for temperature setting, 25 and 27 are reference resistors for voltage comparison, 26 is a thermistor for detecting incoming water temperature, 28 is a thermistor for detecting hot water temperature, and 29 is an analog. Multiplexer, 3
Reference numeral 0 is an A / D converter. The flow rate pulse detected by the water amount sensor is shaped by the pulse shaper 21 and the microcomputer 22
Is input to the PA, and the number of pulses for a certain period of time is calculated inside the microcomputer and converted into the hot water supply amount. The set temperature set by the variable resistor 24 and the incoming water temperature and the outgoing hot water temperature detected by the thermistors 26 and 28 are input from the PB of the microcomputer 22, respectively. The proportional valve output obtained after the calculation in the microcomputer is output from the PC of the microcomputer 22 to the D / A converter 23, converted into an analog value, and becomes a proportional valve output.

Corresponding to the proportional control circuit 11 schematically shown in FIG.
In this embodiment, the pulse shaper 21, the D / A converter 23, the temperature setting variable resistor 24, the voltage comparing reference resistors 25 and 27, the incoming water temperature detecting thermistor 26, the analog multiplexer 29, and the A / D converter. 30 and the microcomputer 22 and a program provided therein.

That is, the set temperature T by the temperature setting variable resistor 24
_set , the incoming water temperature T _in by the incoming water temperature detecting thermistor 26, the outgoing hot water temperature T _out by the outgoing hot water detecting thermistor 28, and the flow rate pulse detected by the water amount sensor are shaped by the pulse shaper 21 and input to the PA of the microcomputer 22, The number of pulses for a certain period of time is calculated in the microcomputer, and the hot water supply amount F converted into the hot water supply amount is obtained by the program with the proportional valve drive voltage Vt = G (T _set , T _in , T _out , F). The function G is a function for bringing T _out close to T _set , and uses the PiD method or the like.

Corresponding to the voltage limiting circuit 12 schematically shown in FIG.
In this embodiment, the microcomputer, and V ₁ ≦ Vt ≦ V ₂ If Vt, <and V ₁ if V _1, Vt> Vt comprising program to V ₂ if V _2, the value D / A converter 2
3 to obtain the proportional valve drive voltage Vl.

In this way, the tapping temperature T _out is set within the range of the minimum proportional valve drive voltage V ₁ and the maximum proportional valve control voltage V _2.
Can be brought closer to _set .

Corresponding to the output arithmetic circuit 13 schematically shown in FIG. 1,
In the present embodiment, the difference (T _in −T _out ) is calculated from the incoming water temperature T _in by the incoming water temperature detecting thermistor 26 and the outgoing hot water temperature T _out by the outgoing hot water temperature detecting thermistor 28 _in the microcomputer, The flow rate pulse detected by the water amount sensor is shaped by the pulse shaper 21 and the microcomputer 2
2 is input to the PA, the number of hot water supply F converted by calculating the number of pulses for a fixed time in the microcomputer, and the above-mentioned (T _in -T
_out ) and a program multiplying

Similarly to the function of the output limiting circuit 14 schematically shown in FIG. 1, in this embodiment, the minimum output value Q ₁ and the maximum output value Q ₂ are stored in the microcomputer as data, and V ₁
And V ₂ are corrected by the following method.

As a method of correction, by comparing the actual hot water output q obtained by (T _out −T _in ) × F when the hot water temperature is stable with the minimum output value Q ₁ and the maximum output Q ₂ stored as data, (i ) If q> Q ₁ and Vt <V ₁ , do not reduce V ₁ .

(Ii) If q <Q ₁ , increase V ₁ .

(Iii) If q <Q ₂ and Vt> V ₂ , increase V ₂ .

(Iv) If q> Q ₂ , do not reduce V ₂ .

By performing the four steps (i) to (iv), the proportional valve drive minimum voltage V ₁ can be obtained at a voltage at which the minimum output value Q ₁ can be obtained, and the proportional valve drive maximum voltage V ₂ can be obtained at a maximum output value Q ₂ . Can approach and maintain voltage.

A series of operations of the above embodiment of the present invention is shown as a flowchart in FIG.

(Effects of the Invention) As described above, according to the present invention, it is not necessary to perform the complicated work of adjusting the maximum and minimum angles of the proportional valve while manually confirming the hot water output, and the proportional valve is also provided. The maximum and minimum hot water output can always be maintained in the same way as at the beginning even if the gas supply capacity of the equipment and the heat exchange efficiency of the heat exchange part change over time, providing a water heater with excellent safety and convenience. can do.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing a temperature control circuit of a water heater of the present invention, FIG. 2 is a block diagram of a conventional temperature control circuit, FIG. 3 is a configuration diagram of a gas water heater, and FIG. FIG. 5 is a circuit diagram showing an embodiment of the invention, and FIG. 5 is a flow chart for explaining the operation of the embodiment of the invention. (Explanation of Codes) 1 ... Water supply channel 2 ... Water amount sensor 3 ... Inlet temperature sensor 4 ... Heat exchange section 5 ... Hot water temperature sensor 6 ... Fuel path 7 ... Fuel proportional valve 8 ... Hot water temperature control circuit 9 ... Temperature setting circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Go Noguchi 1250 Shimoeda, Shimodate, Ibaraki Prefecture Inside the Yuki factory, Hitachi Chemical Co., Ltd. (72) Koji Tajima, 1500 Ogawa, Shimodate, Ibaraki Hitachi Chemical Shimodate Research Institute Co., Ltd.

Claims (1)

[Claims] 1. A water supply passage 1, a water amount sensor 2 provided in the water supply passage 1, and a heat exchange section 4 provided in the water supply passage 1.
A temperature sensor 3 for detecting the incoming water temperature, a temperature sensor 5 for detecting the incoming hot water temperature, and a fuel passage for supplying fuel to the heat exchanging portion 4 6, a fuel proportional valve 7 provided in the middle of the fuel passage 6 for adjusting the flow rate of fuel, a temperature setting circuit for setting a hot water outlet temperature, a hot water supply amount detected by the water amount sensor, and an incoming water detected by the temperature sensor. A hot water temperature control circuit 8 for adjusting the opening of the fuel proportional valve to obtain the hot water temperature set by the temperature setting circuit according to the temperature and the hot water temperature, and a control voltage for presetting the minimum opening of the fuel proportional valve. In a water heater having V ₁ and a control voltage V ₂ with a maximum opening set in advance, a voltage V ₁ in which the maximum opening and the minimum opening of the fuel proportional valve are preset in the hot water outlet temperature control circuit 8
And V ₂ are the product q of the hot water supply amount obtained by the water amount sensor and the difference between the incoming water temperature and the outgoing hot water temperature obtained by the temperature sensor.
And a correction circuit that corrects during hot water supply by comparing the minimum output Q ₁ and the maximum output Q ₂ output by the initially set voltages V ₁ and V ₂ with each other.