JPH025271Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention applies a voltage higher than the rated voltage to the electric heater for burner ignition until the heater temperature reaches the set ignition temperature after the ignition operation, and ,
The gas hot water supply system is equipped with a means for automatically switching the heater voltage so that the rated voltage is then applied, thereby allowing the heater to quickly heat up during ignition operation, thereby shortening the ignition time. Related to various combustion devices such as boilers and gas heaters.

[Conventional technology]

Conventionally, in order to switch the voltage applied to the electric heater for ignition in a combustion device, a variable transformer is used as the power supply transformer for the heater to detect the temperature of the heater, control the timer, or control the current on the secondary side of the transformer due to changes in the temperature of the heater. The variable transformer was configured to automatically switch based on change detection. (For example, Japanese Patent Publication No. 51-11558) [Problems to be solved by the invention] However, since the variable transformer is expensive, there is a problem that the cost of the entire device increases.

The purpose of this invention is to construct a rational heater applied voltage switching circuit using a burner solenoid valve, which is an original component of a combustion device, and to also use this switching circuit configuration as a safety circuit against heater disconnection. The point is to make it so.

[Means for solving problems]

The characteristic configuration of the present invention is that the power supply circuit of the electric heater for igniting the burner, which is made of a ceramic heating element, is equipped with a normally closed relay contact that opens the circuit when the heater temperature reaches the set ignition temperature, and a normally closed relay contact that opens the circuit when the heater temperature reaches the set ignition temperature, and a normally closed relay contact that opens the circuit when the heater temperature reaches the set ignition temperature. The reason is that an electromagnetic solenoid for opening the closed electromagnetic valve is installed in parallel, and its functions and effects are as follows.

[Effect]

In other words, a circuit configuration as shown in Fig. 2 is adopted, and in that circuit configuration, the voltage value (V-Vs) obtained by subtracting the rated operating voltage Vs of the solenoid 6A for operating the solenoid valve from the total voltage V of the power supply circuit 8 In a state in which each rated voltage is preset so that the voltage becomes the rated voltage _VH of the heater 4, after the ignition operation, the current flows through the relay contact 11A, which remains closed until the heater temperature reaches the set ignition temperature. Due to the short-circuit flow, the entire voltage V of the power supply circuit 8, which is higher than the rated voltage V _H of the heater 4, is applied to the heater 4, thereby quickly raising the temperature of the heater 4 to the set ignition temperature.

When the relay contact 11A opens when the heater temperature reaches the set ignition temperature, a current flows through the heater 4 and the solenoid valve solenoid 6A in series. The heater rated voltage V _H obtained by subtracting the rated operating voltage Vs of 6 A is applied to the heater 4, and steady combustion operation is started.

Note that even if the relay contact 11A is open, the heater 4
Since the electromagnetic valve solenoid 6A will not operate if the heater is disconnected, even if, for example, the relay contact 11A is opened under timer control, unexpected fuel release in the heater disconnection state is reliably prevented.

[Effect of idea]

As a result of the above, the short-time heat-up function of the heater can be provided without using a variable transformer as in conventional devices, and the safety function against unburned fuel release can also be provided without any additional configuration. can be prepared, inexpensive, and
A fuel system with excellent safety and high practical effectiveness was created.

Incidentally, it is conceivable to use a heater made of a metal heating element as an electric heater, but the electrical resistance of a metal heating element is inherently much lower than that of a ceramic heating element. Since the rated operating power of the solenoid for solenoid valves is inherently small at only a few watts, when a heater consisting of a metal heating element and a solenoid for solenoid valves are combined in series, general-purpose 100V can be used directly in the power supply circuit. First, the problem arises that the power supply configuration becomes complicated.

In this regard, according to the present invention, since an electric heater made of a ceramic heating element is used, the device configuration can be further simplified and the device cost can be further reduced.
Further, due to the inherent characteristics of the ceramic heating element, it has the advantage of being able to improve durability and ensuring a large amount of ignition heat compared to using a metal heating element.

〔Example〕

Next, embodiments will be described based on the drawings.

FIG. 1 shows a schematic configuration of a gas water heater, which includes a combustion chamber forming casing 1, a gas burner 2, and
A finch tube type water heating heat exchanger 3 heated by this is installed inside, and a red-hot electric heater 4 made of a ceramic heating element is installed as an igniter for the burner 2.

A controller 7 performs ignition and extinguishing operations for the burner 2 based on a manual operation command, and shuts off the electromagnetic gas valve 6 when the burner 2 goes out based on flame detection by the flame rod 5.
It is equipped with.

To configure the ignition and extinguishing operation circuit for the burner 2, in the circuit of the controller 7 as shown in FIG. The power supply circuit 10 of the heater 4 is connected in parallel to the controller power supply circuit 8, and the normally closed relay contact 11A and the solenoid 6A for opening the electromagnetic gas valve 6 are each connected in series to the heater 4. They are interposed in the heater power supply circuit 10 so that they are connected in parallel.

Then, the control circuit 7 in the controller 7 controls the operation relay coil 11 for the relay contact 11A.
It is connected to the timer control circuit in A, and the combustion operation switch 9 is turned ON by the timer control.
The relay contact 11A is configured to be opened and operated when a set time has elapsed from the time of operation, and the sum of the rated voltage _VH of the heater 4 and the rated operating voltage Vs of the solenoid 6A for the solenoid valve becomes 100V. The heater 4 and solenoid 6A are selected in advance as shown in FIG.
The time required for the heater 4 to heat up to the set ignition temperature when 100V is applied is set in advance.

In other words, after turning on the combustion operation switch 9, the controller power supply circuit 8, which is higher than its rated voltage _VH , is connected to the heater 4 via the relay contact 11A, which remains closed until the heater temperature reaches the set ignition temperature.
By applying the full voltage V (100V) of 100V, the heater 4 is heated up to the set ignition temperature in a short time, and when the heater temperature reaches the set ignition temperature, the relay contact 11A is opened. ,
A current is applied to the solenoid 6A for the solenoid valve to open the solenoid gas valve 6, and the heater rated voltage V _H , which is obtained by subtracting the rated operating voltage Vs of the solenoid 6A for the solenoid from the total voltage V (100V) of the controller power supply circuit 8, is applied to the heater. 4 to start steady combustion operation.

Furthermore, by connecting the heater 4 and the electromagnetic valve solenoid 6A in series, the electromagnetic gas valve 6 is reliably prevented from opening when the heater 4 is disconnected, thereby preventing an unexpected raw gas leakage accident. There is.

[Another example]

Next, another embodiment will be described.

Instead of controlling the relay contact 11A by timer control, the opening operation of the relay contact 11A may be performed based on temperature detection of the heater 4 or detection of a change in the current passing through the heater due to a change in the heater temperature.

The present invention can be applied to various combustion devices such as gas water heaters and space heaters.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a schematic overall structural diagram and FIG. 2 being a circuit diagram. 2... Gas burner, 4... Heater, 6... Solenoid valve, 6A... Solenoid, 10... Heater power supply circuit, 11A... Relay contact.

Claims (1)

[Scope of utility model registration request] After the ignition operation, a voltage higher than the rated voltage is applied to the electric heater 4 for burner ignition until the heater temperature reaches the set ignition temperature, and then the heater voltage is automatically changed so that the rated voltage is applied. The combustion apparatus is equipped with switching means, and the switching means is a normally closed type that opens a circuit when the heater temperature reaches a set ignition temperature in the power supply circuit 10 of the heater 4 made of a ceramic heating element. A combustion device in which a relay contact 11A and an electromagnetic solenoid 6A for opening/opening a normally closed electromagnetic valve 6 for disconnecting fuel supply to the burner 2 are interposed in parallel.