JPH08166130A - Ignition heater - Google Patents

Abstract

PURPOSE: To obtain an ignition heater which can adjust variations in a resistance value thereof without connection work of an added resistance. CONSTITUTION: In an ignition heater which checks a change in a resistance value in a flame of a ceramic ignition heater to detect a fading, it is necessary to correct errors of the resistance value of the ignition heater for detecting the fading at a high accuracy and exactly. In a switch variable resistance 56, addition resistors R1-R18 are connected in series to a basic resistor RO and an opening-closing switch SW1 is provided at the connection point thereof to allow opening or closing of the resistors. With the setting of opening or closing switches S1-S18, an output resistance value can be set selectively by stages to detect the fading of the flame from the resistance value and the resistance value of the ceramic ignition heater.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition heater, and more particularly to an ignition heater in which a resistor is formed on a support made of a ceramic material and a resistor is energized to ignite gas or the like.

[0002]

2. Description of the Related Art A gas heater is known that ignites gas by energizing a resistor. As this ignition means, there is known a ceramic ignition heater in which a resistor is formed on a support made of a ceramic material and a gas is ignited by energizing the resistor. If the flame extinguishes due to some cause after igniting gas etc. by such a ceramic ignition heater,
For safety, prompt detection and stopping of gas supply are required. Conventionally, a frame sensor has been used as a means for detecting the extinction of such a flame.

However, in the above-mentioned conventional gas heater, since the ignition means and the means for detecting the extinction are respectively provided, there is a drawback that many members are arranged in the flame. In order to solve this drawback, the applicant proposes a gas heater using a ceramic ignition heater in Japanese Patent Application No. 2-415791. When the gas is ignited by the ceramic ignition heater, the resistance value of the ceramic ignition heater changes. Based on the above, a technique for detecting the extinction of flame has been disclosed.

[0004]

However, in the technique disclosed above, the resistance value of the ceramic ignition heater varies. Since this variation affects the time at which the extinction is detected, it has been proposed in the above application to add a resistor having an appropriate value according to the variation value and correct the resistance value of the ceramic ignition heater to a reference value. . For such a correction, it is necessary to select a correction resistor having an appropriate resistance value according to the resistance value of each ceramic ignition heater, and connect and fix it to a predetermined circuit portion using a soldering iron or the like. . However, for example, in a gas heater for livestock, since the above-mentioned correction resistor is also housed in the casing of the control circuit for waterproofing, the connection and fixing work is troublesome and the adjustment is time-consuming.

It is an object of the present invention to provide an ignition heater which makes it possible to easily adjust the variation in the resistance value of the ignition heater.

[0006]

According to the ignition heater of the present invention, a ceramic ignition heater, a plurality of resistors and a switch are provided, and the resistance value can be selectively set stepwise by opening and closing the switch. Variable resistance means, resistance value detecting means for detecting the resistance value of the ceramic ignition heater arranged in the flame, extinguishing detection means for detecting extinction of the flame based on the resistance value output from the resistance value detecting means, and The resistance value detecting means detects the resistance value of the ceramic ignition heater corrected from the resistance value of the ceramic ignition heater and the resistance value set by the additional variable resistance means, and adds the resistance value detecting means. By opening / closing the switch of the variable resistance means, the error of the resistance value of the ceramic ignition heater is corrected stepwise, and the extinction detection means is based on the corrected resistance value, and the extinguishing detection means It is characterized in that it is possible to detect the example.

Further, the additional variable resistance means has a basic resistor forming a basic resistance value and a plurality of addition resistors connected in series with the basic resistor, and the additional resistor is composed of the basic resistor and the addition resistor. It is preferable that the number of stages connected in series can be selected by opening and closing a switch. Alternatively, the additional variable resistance means has a basic resistor forming a basic resistance value, and a plurality of parallel resistors connected in parallel to the basic resistor, and the parallel resistor and the basic resistor are connected in parallel. It is recommended that it be selectable by opening and closing the switch. Further, the switch is preferably a dip switch.

[0008]

Embodiments of the ignition heater according to the present invention will now be described in detail with reference to the accompanying drawings. As the prior invention related to the present invention, the prior application by the present applicant, Japanese Patent Application No. 6-15
No. 7527 "Ignition Heater", one example of a method of correcting the resistance value of a ceramic ignition heater is described in detail.

FIG. 3 is a block diagram showing the circuit configuration of this embodiment. The ceramic ignition heater 40 is as shown in FIG. 4, and as shown in FIG.
4) A resistor 44 is formed by printing on a ceramic base material 42 formed of ceramic, and is fired together with another ceramic base material 46 as shown in FIG. 6, and then metallized. Furthermore, as shown in FIG.
50 connected.

As shown in FIG. 3, a ceramic ignition heater
The 40 and the power source 66 are connected to ignite the gas, and the resistance value detection circuit 54 and the ceramic heater 40, the switching variable resistor 56 and the extinction detection circuit 52 are connected to detect the extinction of the gas. The control circuit 60 is a circuit unit that controls the entire operation, and is connected to the extinction detection circuit 52, the timer circuit 62, the switch 68, the solenoid valve 64, and the power supply 66.

In each circuit portion having the above-mentioned connection relationship, the ceramic ignition heater 40 has excellent heat resistance and is used as an igniter material and also as a sensor for detecting the extinction of the flame. The ceramic ignition heater 40 is
It is energized by the power supplied from the power supply 66 and becomes high temperature,
After a lapse of a predetermined time, the gas is heated to a high temperature and then the supplied gas is ignited. The resistance value of the ceramic ignition heater 40 changes according to the temperature change.

The resistance value detection circuit 54 is a circuit portion for detecting the resistance value of the ceramic ignition heater 40. The resistance value of the ceramic ignition heater 40 used at the reference temperature (generally 25 ° C.) is calculated by the resistance value detection circuit 54 in advance. The resistance value of the ceramic ignition heater 40 detected by the resistance value detection circuit 54 changes depending on the temperature. Also,
The resistance value of the ceramic ignition heater 40 varies and is different for each ceramic ignition heater 40. Therefore, a switching resistance is added according to the magnitude of the variation, and the resistance value detection circuit 54 detects the corrected resistance value. The resistance correction is provided by the connection with the switching variable resistor 56. The corrected resistance value detected by the resistance value detection circuit 54 is sent to the fading detection circuit 52.

The extinction detecting circuit 52 includes a resistance value detecting circuit 54.
The resistance value of the ceramic ignition heater 40 at that time is detected based on the resistance value obtained from the above, and the extinction of the flame is detected by comparing this with a predetermined resistance value set in advance. Normally, 300-500 ° C when flame is generated
At this time, the resistance value of the ceramic ignition heater 40 is detected,
When the flame is extinguished, the temperature decreases and the detected resistance value decreases, so that the extinction of the flame can be detected. For example, 100 ℃
The resistance value at time is used as the resistance value for extinguishing the flame.

The control circuit 60 is a control circuit which is advantageously constituted by a microprocessor and which receives an input from the switch 68 or an erasure determination signal sent from the erasure detection circuit 52 and controls each part. The timer circuit 62 is composed of a timer that measures a predetermined time, and particularly in the present heater, determines the elapsed time for energizing the ceramic ignition heater 40 from the power source 66 and controlling the opening / closing of the solenoid valve 64.

The solenoid valve 64 is provided in a nozzle pipe (not shown) and controls the supply of gas to the gas burner. Also,
The switch 68 is a switch for the operator to input various instructions to the ignition heater, and inputs, for example, an instruction for resistance measurement, setting of the extinction judgment temperature, and an instruction for ignition.

Based on the resistance value previously detected before the ceramic ignition heater 40 is used, the switching variable resistor 56 is switched so that the resistance value becomes a constant resistance value. By switching the switching variable resistor 56, the resistance value of the ceramic ignition heater 40 to which the resistance value of the switching variable resistor 56 is added becomes a constant value.
The configuration for switching the switching variable resistor 56 will be described below.

FIG. 1 shows an example of the circuit configuration of the switching variable resistor 56. This circuit is a circuit that is connected in parallel with the resistance of the ignition heater of the ceramic ignition heater 40 to adjust the variation in the resistance of the ignition heater 40, and is composed of 19 resistors and a dip switch SW1.

In FIG. 1, one basic resistor R0 and eighteen summing resistors R1 to R18 are connected in series between two terminals 1 and 2. In addition, the series connection point of each resistor,
ON / OFF between the connecting line between the adding resistor R18 and terminal 2
18 open / close contacts S1 to S18 that can select and set short-circuit connection
DIP switch SW1 is provided. Therefore, the resistance R of this circuit is 1 from the time when all the switching contacts S1 to S18 are opened until the switching contacts S1, S2, ..., S18 are sequentially closed.
9-step selection setting is possible.

When the resistance value of the ceramic ignition heater 40 differs from the reference value 90Ω (25 ° C.) and varies, the resistance value is adjusted to the reference resistance value by adjusting the resistance R. The resistance value of the ceramic ignition heater 40 is 81-
Since the range of 99Ω is acceptable and is commercially available, this range is divided into 19 steps for each 1Ω, and the reference value is set by opening / closing the above-mentioned 18 opening / closing contacts S1 to S18.

Therefore, the resistance value of the ceramic ignition heater 40 is measured before use, and the resistance to be connected is established by opening / closing the 18 opening / closing contacts S1 to S18 depending on which of 19 steps of 81 to 99Ω. Adjust the value of R in 19 steps.

Therefore, even if the resistance value of the ceramic ignition heater 40 varies from 81Ω to 99Ω, the resistance can be made constant by adjusting the opening / closing of the opening / closing contacts S1 to S18 of the switch SW1.

In the above embodiment, the resistance value of 81 to 99Ω of the ceramic ignition heater 40 is adjusted in 19 steps by the additional resistance, but it is adjusted in 5 steps, for example. Good. That is,
81-84Ω, 85-88Ω, 89-92Ω, 93-9
It is divided into 5 ranges of 6 Ω and 97 to 99 Ω, and it is detected which range of the ceramic ignition heater 40 to be used falls within these ranges, and the switch SW1 has four opening and closing contacts to make five-step adjustment. You may Further, the switch SW1 may have another number of open / close contacts, and the adjustment may be performed in stages corresponding thereto.

According to the above apparatus, the variation in the resistance of the ceramic ignition heater 40 can be digitally and easily adjusted by only the open / close adjustment of the open / close contacts S1 to S18 of the switch SW1. Further, it is not necessary to prepare a soldering iron and various kinds of resistors having different resistance values for correction for this adjustment.

As the above switch SW1, a dip type switch is predominantly used in consideration of the convenience of the circuit configuration and adjustment work, the durability in the usage environment of the gas heater, etc., but the switch type is independent. It is possible to select and use the optimum one of the circuit type, the rotary type, the jump connection type and the like.

FIG. 3 shows an embodiment using a rotary switch. In the case of this embodiment, the contacts S connected to the nineteen resistors R101 to R119 arranged in a circle.
Select the connection between 101-S119 and switch S, and
, 6, a predetermined resistance value is selectively set.

FIG. 2 shows another example of the circuit configuration of the switching variable resistor 56. The major difference between this circuit and the example of FIG.
This circuit is a parallel circuit and is different from the series circuit of FIG.

In FIG. 2, one basic resistor R200 and eighteen parallel resistors R201 to R218 are connected in parallel between the two terminals 3 and 4. Also, each parallel resistor R201-
R218 is provided with switching contacts S201 to S218 in series,
It is configured by being connected in parallel with the basic resistor R200.
The 18 open / close contacts S201 to S218 are configured as a switch SW2 to turn on the parallel resistors R201 to R218.
/ OFF connection can be selected and set. Therefore, the resistance R of this circuit can be selectively set in 19 steps by closing all of the switching contacts S218, S217, ..., S201 after all the switching contacts S201 to S218 are opened.

Before using this heater, first, the resistance value of the ceramic ignition heater 40 is measured, and the switching variable resistor 56 is switched according to the measurement, and the resistance value is adjusted to a constant value.

The resistance value used by the fading detection circuit 52 to detect the fading is preset.
Based on this setting, the resistance value measured by the resistance value detection circuit 54 is sent to the erasure detection circuit 52, and it is determined whether or not the erasure has occurred.

When the operator inputs an ignition instruction from the switch 68, this instruction is sent to the control circuit 60, and the control circuit 60 outputs a control signal to the power supply 66. Power 66 to power line 50
The ceramic ignition heater 40 is energized and heated. When energization of the ceramic ignition heater 40 is started, a control signal is output from the control circuit 60 to the timer circuit 62, and the timer circuit 62 measures a predetermined time. After a lapse of a predetermined time, for example, 10 seconds, the ceramic ignition heater 40 heats to reach the ignition temperature of the gas, for example, 1200 ° C.
Then, when the timer circuit 62 measures the elapse of 10 seconds, the control circuit 60 opens the solenoid valve 64 according to the output from the timer circuit 62 to supply the gas to the burner. This ignites the gas and starts combustion.

After the solenoid valve 64 is opened and combustion is started,
A control signal is output from the control circuit 60 to the timer circuit 62, and the timer circuit 62 measures a predetermined time. When the timer circuit 62 measures a predetermined time, for example, 10 seconds, a control signal is output from the control circuit 60 to the power source 66, and the energization of the ceramic ignition heater 40 is stopped. In this way, the deterioration of the ceramic ignition heater 40 is prevented by stopping the power supply to the ceramic ignition heater 40 after a predetermined time has elapsed after ignition.

Since the ceramic ignition heater 40 is exposed to the flame during normal combustion after ignition,
The ceramic ignition heater 40 keeps being heated to a high temperature by the flame. However, if the flame is extinguished by some cause, for example, the wind hits the ceramic ignition heater 40, the flame does not hit the ceramic ignition heater 40, and the temperature of the ceramic ignition heater 40 gradually decreases. As described above, since the resistance value of the ceramic ignition heater 40 is adjusted to the reference resistance value by the switching variable resistance, this resistance value is detected by the resistance value detection circuit 54, and the flame extinction is detected in the extinction detection circuit 52. To be detected.

When the extinguishment detection circuit 52 detects extinguishment of the flame, the control circuit 60 outputs a control signal to the solenoid valve 64 and the power supply 66 in response to the signal from the extinction detection circuit 52. As a result, the solenoid valve 64 is closed, the gas supply is immediately stopped, and the ceramic ignition heater 40 is energized again from the power supply 66, and the ceramic ignition heater 40
Is heated. As mentioned above, the ceramic ignition heater 40
When, for example, 10 seconds have passed after the start of energization to the ceramic ignition heater 40, the ignition temperature of the ceramic ignition heater 40 reaches 1200 ° C., so that the solenoid valve 64 is opened and the gas is supplied again.

As described above, according to the ignition heater of this embodiment, the ceramic ignition heater 40 is used as the ignition means and also as the flame extinction detection means. In this configuration, the variation of the resistance value of the ceramic ignition heater 40 is adjusted by a simple switching circuit. Further, since the adjustment is performed only by the opening / closing contact, it is possible to perform the adjustment based on a predetermined procedure while observing the numerical values of the adjusting device which is configured in advance. Further, this adjustment only requires opening a predetermined lid and switching the switch, and does not require skill or specialized knowledge. After the adjustment, regardless of the variation in the resistance value of the ceramic ignition heater 40 used, a constant temperature can be detected and the extinction of the flame can be accurately detected.

Further, at the time of ignition, the solenoid valve 64 is opened after a lapse of a predetermined time after the ceramic ignition heater 40 is energized,
When the extinguishment is detected, the solenoid valve 64 is immediately closed and the ceramic ignition heater 40 is energized, so that ignition and re-ignition at the time of extinguishment can be performed safely and appropriately.

[0036]

The ignition heater according to the present invention is constructed such that the resistance added by opening and closing the switch can be selectively set stepwise, and the ceramic ignition disposed in the flame is based on the corrected resistance value of the ceramic ignition heater. Detects the extinction of the flame by detecting the resistance value of the heater. Therefore, by opening / closing the switch, it is possible to accurately detect the extinction of the flame based on the resistance value of the ceramic ignition heater whose error is corrected stepwise.

According to the ignition heater of the present invention, the variation in the resistance of the ceramic ignition heater can be easily adjusted digitally by only opening and closing the switch. In addition, this adjustment does not require preparation and connection of a soldering iron and various resistors with different resistance values for correction, and it is necessary to open the lid of the box containing the control circuit for connection work. Moreover, the adjustment is easy, and the waterproofness of the gas heater is not hindered.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an example of a configuration of a switching variable resistor used in an ignition heater according to the present invention.

FIG. 2 is a circuit diagram showing another example of the configuration of the switching variable resistor used in the ignition heater according to the present invention.

FIG. 3 is a circuit diagram showing another example of the configuration of the switching variable resistor used in the ignition heater according to the present invention.

FIG. 4 is a block diagram showing an embodiment of an ignition heater according to the present invention.

FIG. 5 is a front view showing a ceramic heater.

6 is a perspective view showing a manufacturing process of the ceramic heater of FIG. 4. FIG.

FIG. 7 is a perspective view showing a manufacturing process of the ceramic heater of FIG.

8 is a diagram showing a configuration of the ceramic heater of FIG.

[Explanation of symbols]

 1, 2, 3, 4 terminals 40 ceramic heater 42 ceramic base material 44 resistor 50 power supply line 52 extinguishing detection circuit 54 resistance value detection circuit 56 switching variable resistance 60 control circuit 62 timer circuit 64 solenoid valve 66 power supply 68 switch R0, R200 Basic resistor R1 to R18 Summing resistor R201 to R218 Parallel resistor R101 to R119 Resistor

Claims (5)

[Claims] 1. A ceramic ignition heater, an additional variable resistance means having a plurality of resistors and a switch, wherein the resistance value can be selectively set stepwise by opening / closing the switch, and a ceramic arranged in the flame. It has resistance value detecting means for detecting the resistance value of the ignition heater, extinguishing detection means for detecting extinction of flame based on the resistance value output from the resistance value detecting means, and control means for controlling each of the above means. The resistance value detection means detects the resistance value of the ceramic ignition heater corrected from the resistance value of the ceramic ignition heater and the resistance value set by the additional variable resistance means, and the resistance value of the switch of the additional variable resistance means is detected. By opening and closing, the error of the resistance value of the ceramic ignition heater is corrected stepwise,
An ignition heater, wherein the extinction detecting means can detect extinction of the flame based on the corrected resistance value. 2. The additional variable resistance means includes a basic resistor forming a basic resistance value and a plurality of summing resistors connected in series with the basic resistor, and the basic resistor and the summing resistor. 2. The ignition heater according to claim 1, wherein the number of stages connected in series with the resistor can be selected by opening and closing the switch. 3. The additional variable resistance means includes a basic resistor forming a basic resistance value and a plurality of parallel resistors connected in parallel to the basic resistor, and the parallel resistor and the basic resistor. The ignition heater according to claim 1, wherein a parallel connection with a heater is made selectable by opening and closing the switch. 4. The ignition heater according to claim 1, wherein the switch is a DIP switch. 5. The ignition heater according to claim 1, wherein the switch is a rotary switch.