JPS6373018A - Controller for water heater - Google Patents

Abstract

PURPOSE:To permit the interception of a solenoid valve in a condition that the value of CO/CO2 is low even when the amount of combustion of gas is small and improve the safety of the title device, by a method wherein the solenoid valve is closed the generating electromotive force of a reverse thermocouple becomes higher than a given level. CONSTITUTION:A first operational amplifier 17 outputs Lo signal when the sum or a composite electromotive force of electromotive forces generated from a main thermocouple 13 and a reverse thermocouple 14 becomes lower than a given level while a second operational amplifier 18 outputs the Lo signal when the electromotive force, generated from the reverse thermocouple 14, becomes higher than the given level. An AND logical element 19 outputs the Lo signal when the first operational amplifier 17 or the second operational amplifier 18 outputs Lo signal or both of the first operational amplifier 17 and the second operational amplifier 18 output the Lo signals while a solenoid valve 15 is intercepted by the Lo signal. Thus, a circuit, closing the solenoid valve when the electromotive force generated from the reverse thermocouple becomes higher than the given level, is provided, therefore, when the fin of a heat exchanger is clogged even in the case of small combustion amount of gas, the solenoid valve is closed during a time when the blockading rate of the fin or the value of CO/CO2 is low whereby the safety of the title device may be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control device for a gas instantaneous water heater or the like used in a kitchen or the like.

BACKGROUND OF THE INVENTION In recent years, small gas instantaneous water heaters have been equipped with devices to prevent incomplete combustion when there is a lack of oxygen or when the heat exchanger fins are clogged, and safety has become important.

An example of the above-mentioned conventional small gas instantaneous water heater will be described below with reference to the drawings.

FIG. 3 shows an overall configuration diagram of a conventional small-sized gas instantaneous water heater.

In FIG. 3, 1 is a main faucet installed in the water supply channel, 2 is a water governor, and 3 is a heat exchanger. 4 is a solenoid valve provided in a gas supply passage, 5 is a gas governor, and 6 is a water pressure-responsive gas valve that responds to the pressure of water flowing through the water supply channel. 7 is the ignition device, 8 is the main burner, 9 is the pilot burner, 1
o is the main thermocouple for detecting ignition of the pilot burner 9;
Reference numeral 1 denotes an inverted thermocouple for detecting fin clogging in the heat exchanger 3, which is read directly so as to apply a back electromotive force to the main thermocouple 10.

12 is a control circuit that controls the entire device.

The operation of the small-sized gas instantaneous water heater configured as described above will be explained below.

First, when the ignition button is pressed, the solenoid valve 4 is opened, gas flows to the pilot burner 9, and the ignition device 7 ignites the gas. When the pilot burner 9 is ignited, the main thermocouple 10 for detecting pyrosotonomina ignition is heated and an electromotive force is generated. The solenoid valve 4 is forcibly maintained in the open position 11 for a certain period of time (hereinafter referred to as forced adsorption time) after the ignition operation by the control circuit 12. At the same time, main faucet 1 is opened and water governor 2 is opened.
The amount of water is adjusted to a constant amount and flows to the heat exchanger 3. This flow of water causes the hydraulically responsive gas valve 6 to open and the gas governor 5 to open.
The gas adjusted to a constant gas amount flows to the main burner 8, is ignited by the pilot burner 9, and is combusted. The heat exchanger 3 is heated by this combustion gas, and water is heated to obtain hot water.

Here, the electromotive force generated from the main thermocouple 10 and the reverse thermocouple 11 and the operation of the solenoid valve 4 will be explained with reference to the drawings. FIG. 4 is a diagram showing the relationship between the generation of electromotive force of the main thermocouple 10 and the reverse thermocouple 11 and time during ignition. Figure 5 shows the oxygen concentration and the electromotive force of the main thermocouple 10 and reverse thermocouple 11,
It is a figure showing Co/CO2. Figure 6 shows the fin occlusion rate of the heat exchanger 3 and the respective effects of the main thermocouple 10 and reverse thermocouple 11.
FIG. 2 is a diagram showing Co/CO2. As shown in FIG. 4, after the ignition operation of the main burner 8, the electromotive force of the main thermocouple 10 heated by the pyro 7 burner 9 and the reverse thermocouple 11 heated by the combustion gas of the main burner 8 increases with time. going up. Here, the combined electromotive force (main thermocouple 10 and reverse thermocouple 1
1) is higher than the cutoff voltage of the electromagnetic valve 4 after forced adsorption, the electromagnetic valve 4 is kept open by the combined electromotive force, and combustion continues. If the above-mentioned combined electromotive force is lower than the cutoff voltage of the solenoid valve 4, the solenoid valve 4
The gas supply will be cut off. Therefore, if the gas instantaneous water heater is used for a long time and the oxygen concentration in the air in the room where the gas instantaneous water heater is installed decreases as shown in Figure 5, the combustion of the pilot burner 9 will become unstable and the main thermocouple 1o
The emf of is reduced, and the combined emf is reduced. When this combined electromotive force falls below the cutoff voltage of the solenoid valve 4, the solenoid valve 4 is cut off and gas supply is stopped to prevent an oxygen deficiency accident.

Further, as shown in FIG. 6, if the fin blockage rate of the heat exchanger 3 increases due to some accident, the electromotive force of the inverse thermocouple 11 increases,
As a result, the composite electromotive force decreases.

When the combined electromotive force falls below the cutoff voltage of the solenoid valve 4, the solenoid valve 4 is cut off, stopping the gas supply and preventing incomplete combustion in the main burner 8. Figure 7 shows the fin blockage rate of heat exchanger 3 and the main thermocouple 10 when the amount of gas combustion is reduced.
, is a diagram showing each electromotive force of the inverse thermocouple 11 and Co/CO2.

Problems to be Solved by the Invention However, with the above configuration, as shown in FIG. The resulting electromotive force increases, and as a result, the combined electromotive force decreases. Therefore, the blockage rate when shutting off the solenoid valve 4 increases,
The value of Co/CO2 becomes large and becomes unsafe. Therefore, increasing the cutoff pressure of the solenoid valve 4 will make it safer in the case of lack of fermentation and fin blockage, but if the combined electromotive force after forced adsorption at the initial stage of ignition is lower than the cutoff voltage of the solenoid valve 4, then the solenoid valve 4 There was a problem that the equipment could not be used due to the disconnection. Also, if you extend the forced adsorption time,
A lot of forced adsorption time is required for that time, and the solenoid valve 4
The dry cell battery used as a power source runs out quickly. Furthermore, if the forced adsorption time is made longer, raw gas will be emitted for a longer time if the ignition spark does not ignite, which poses a safety problem.

In view of the above considerations, the present invention shuts off the solenoid valve 4 on the safer side and stops the gas supply while the Co/CO2 value is low when the fins are closed, regardless of the amount of gas burned. This eliminates the problem of extinguishing a fire due to insufficient electromotive force, and provides a safer and more convenient gas instantaneous water heater.

Means for Solving the Problems In order to solve the above problems, the gas instantaneous water heater of the present invention has a main thermocouple that is heated by a pilot burner to generate an electromotive force, and a main thermocouple that is attached to a heat exchanger. A reverse thermocouple for detecting fin clogging that generates a reverse hidden electromotive force, a solenoid valve installed in a part of the gas passage to control fuel supply to the main burner and pilot burner, and the main thermocouple and the a pilot safety circuit that closes the solenoid valve when the composite electromotive force generated from the inverse thermocouple falls below a certain level, or when the electromotive force generated from the inverse thermocouple exceeds a certain level; It is prepared.

Effect: With the above-described configuration, the present invention shuts off the solenoid valve when the electromotive force generated from the inverted thermocouple exceeds a certain level, so even when the amount of gas burnt is small, the heat exchanger remains closed. The electromagnetic valve can be shut off in state R where the blockage rate is low and the Co/CO2 value is low, increasing safety.

EXAMPLE Hereinafter, a gas instantaneous water heater according to an example of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of a gas instantaneous hot water system according to an embodiment of the present invention, in which the same parts as in the prior art are given the same reference numerals, detailed explanations are omitted, and different parts will be mainly explained.

13 is a main thermocouple that is heated by the pilot burner 9 and generates an electromotive force; 14 is an inverse thermocouple for detecting fin clogging that is attached to the heat exchanger 3 and generates an electromotive force that is opposite to the main thermocouple 13; 15 is a solenoid valve, 16 is a main thermocouple 13 and a reverse thermocouple 14
This is a pilot safety circuit connected to the series circuit of the solenoid valve 15 and to the solenoid valve 15. FIG. 2 shows an example of the pilot safety circuit. When the composite electromotive force, which is the sum of the electromotive forces generated from the main thermocouple 13 and the reverse thermocouple 14, falls below a certain level in the first operational amplifier 17, an LO multiplication signal is generated. The second operational amplifier 18 outputs a Lo times signal when the electromotive force generated from the inverse thermocouple 14 exceeds a certain level.

Reference numeral 19 denotes an AND logic element which outputs an LO multiplied signal when the first operational amplifier 17 is at Lo and the second operational amplifier 18 is at Lo% or when both the first operational amplifier 17 and the second operational amplifier 18 are at Lo. The solenoid valve 15 is cut off by this Lo multiple signal. That is, compared to the conventional system, the number of circuits that shut off the solenoid valve 15 when the electromotive force generated from the inverted thermocouple 14 exceeds a certain level is increased, and a safer gas instantaneous hot water heater can be provided.

Effects of the Invention As described above, the present invention provides a circuit that shuts off the solenoid valve when the electromotive force generated from the inverted thermocouple exceeds a certain level, so that even when the amount of gas burned is small, the fins of the heat exchanger can be C
Since the electromagnetic valve can be shut off and the gas supply can be stopped while the o/CO2 value is low, safety can be improved.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of a gas instantaneous water heater according to an embodiment of the present invention, Fig. 2 is a pilot safety circuit diagram of the same, and Fig. 3 is an overall diagram of a conventional gas instantaneous water heater] 7G diagram, Fig. 4 The figure is a characteristic diagram of the conventional electromotive force, Figure 5 is a characteristic diagram of the electromotive force during oxygen deficiency, Figure 6 is a characteristic diagram of the electromotive force when the fins are closed at the maximum gas combustion amount, and Figure 7 is a characteristic diagram of the electromotive force when the fins are closed. It is a characteristic diagram of the electromotive force when the fin is closed when the gas combustion amount is at its minimum. 13... Main thermocouple, 14... Reverse thermocouple, 15... Solenoid valve, 16... Pilot safety circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person l3
-Main side i-kaku f4-reverse electric power go 15-electronic expansion fb--nomai [19 to reward bon outside 1st (21 power water snow 3-koni hand basket down 1 f4-reverse gore danger Light 7.5 - Riding Insects Cell 17 - O Duke Assib No. 2 Fig. r8-4 Takumi Amp b Fig. 3 ZA - Fig. 4 1 Thread 11 Discharge - = Fig. 5 Fig. 02 Concentration No. 60 Fin Blocked banknotes

Claims (1)

[Claims] A pilot burner, a main thermocouple that is heated by the pilot burner and generates an electromotive force, a main burner, a heat exchanger that is heated by the main burner, and a thermocouple that is heated by combustion gas between the heat exchanger and the main burner. , and a reverse thermocouple for detecting fin clogging that generates an electromotive force of opposite polarity to that of the main thermocouple; a solenoid valve provided in a part of the gas passage to control fuel supply to the main burner and the pilot burner; When the combined electromotive force generated from the main thermocouple and the reverse thermocouple falls below a certain level, or when the electromotive force generated from the reverse thermocouple exceeds a certain level, the solenoid valve is closed. A water heater control device consisting of a pilot safety circuit.