JPS61295425A - Combustion device - Google Patents

Abstract

PURPOSE:To prevent unexpected continuation of imperfect combustion operation by a method wherein intercepting operation of valve mechanism, effected by an imperfect combustion preventing means, is precluded during a set time from the time point of burner ignition operation to decide whether a sensor has detected the condition of imperfect combustion immediately after the ignition operation. CONSTITUTION:A time limit restraint circuit 13D, precluding the gas valve closing operation of an imperfect combustion preventing circuit 13C during a set time DELTAt from the time point of ignition operation in spite of the value of density detected by sensor 10, is incorporated into a control unit 13 to avoid unnecessary extinction of the burber 3 due to the condition of imperfect combus tion (temporary reduction of measured resistance value (r)) which is caused inevitably immediately after the ignition operation. According to this method, the sensor 10 is checked through self-diagnosis whether it functions normally utilizing the imperfect combustion condition caused inevitably immediately after the ignition operation to avoid previously the unexpected imperfect combus tion operation due to deterioration of sintered film 16 of SnO2, disconnection of electrode wires 17, malfunction of an electric heater 18 or the like.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to various combustion devices such as instantaneous water heaters and fan heaters, and more specifically, to a valve mechanism that shuts off fuel supply to a burner, and a valve mechanism that shuts off fuel supply from the burner. a sensor for detecting the concentration of combustible gas components in the combustion gas, and an incomplete combustion prevention means for automatically shutting off the valve mechanism when the concentration detected by the sensor exceeds a set upper limit concentration; A time limit check means is provided to prevent the incomplete combustion prevention means from shutting off the valve mechanism for a set time from the time of the ignition operation for the burner, regardless of the concentration detected by the sensor, so that the extremely short period of time that always occurs immediately after the ignition operation is provided. The present invention relates to a combustion device in which a sensor detects an incomplete combustion state of a burner and prevents the fuel supply to the burner from being automatically stopped unnecessarily by using a time limit check means, and allows combustion operation to be continued appropriately.

[Conventional technology]

Conventionally, combustion devices such as those described above have a function to self-diagnose whether or not the sensor that detects the concentration of combustible gas components in the combustion gas from the burner is functioning normally. There was nothing (unable to provide references).

[Problem that the invention seeks to solve]

However, if combustion operation is started when there is a problem with the sensor, such as when the sensor has deteriorated and its sensitivity has decreased, the incomplete combustion prevention means will not operate properly, and incomplete combustion may unexpectedly occur due to some reason. There is a risk that the problem will continue, and as a result, there is a problem of unexpected problems with the combustion equipment, such as a lack of oxygen in the room and clogging of soot.

The purpose of the present invention is to enable accurate self-diagnosis of whether the sensor's combustible gas concentration detection function is appropriate or not, through rational improvements that effectively utilize the inherent operating characteristics of combustion equipment, and to prevent sensor troubles such as sensor deterioration. The object of the present invention is to reliably prevent an unexpected continuation of incomplete combustion operation caused by starting combustion operation in a certain state.

[Problem that the invention seeks to solve]

The characteristic configuration of the combustion apparatus according to the present invention is such that the time-limiting check means prevents the shutoff operation of the fuel supply cutoff valve mechanism by the incomplete combustion prevention means, regardless of the concentration of combustible gas components detected by the sensor. Means is provided for determining whether or not the concentration detected by the sensor exceeds the set standard concentration within a set time, and based on the determination result by the determining means, when the concentration does not exceed the set standard concentration, the set standard concentration is determined. If the valve mechanism is operated to shut off the incomplete combustion with priority over the incomplete combustion prevention means at the time when the set time has elapsed, and the set standard concentration is exceeded, after the set time has elapsed, the valve mechanism is operated to shut off the incomplete combustion The purpose is to provide a safety means that maintains the non-shutoff state while prioritizing the shutoff operation by the prevention means, and its functions and effects are as follows.

[For production]

In other words, the time-limiting means prevents the incomplete combustion prevention means from shutting off the valve mechanism for a set period of time after the burner ignition operation, regardless of the concentration detected by the sensor.
This is to prevent the fuel supply from being cut off unnecessarily due to the sensor detecting the incomplete combustion state that always occurs immediately after the ignition operation. The following control is performed by effectively utilizing the inherent operating characteristics of the combustion device that occur.

That is, by having the determining means determine whether or not the concentration detected by the sensor exceeds the set standard concentration within the set time period for preventing the incomplete combustion prevention means from shutting off the valve mechanism, incomplete combustion immediately after the ignition operation is prevented. It is determined whether the sensor has detected the state.

As a result of this determination, if the sensor detection concentration does not exceed the set reference concentration, that is, if the sensor does not detect the incomplete combustion state that always occurs immediately after the ignition operation, the sensor detection function is activated. It is determined that there is a problem with the sensor, such as when the concentration has decreased, and the valve mechanism' is prioritized over the incomplete combustion prevention means after a set time elapses.In other words, the detected concentration of the sensor is below the set upper limit concentration. regardless of whether the interrupt is activated, thereby
Prevents unexpected incomplete combustion caused by sensor trouble such as sensor deterioration.

Additionally, as a result of the determination, if the sensor detected concentration exceeds the set reference concentration, that is, if the sensor detects an incomplete combustion state that always occurs immediately after the ignition operation, the sensor's detection function is appropriate. After the set time has elapsed, the valve mechanism is set to stop while prioritizing the shutoff operation by the incomplete combustion prevention means, in other words, while taking advantage of the incomplete combustion prevention function based on the concentration detection by the sensor. The shut-off state is maintained, thereby allowing the continuation of steady combustion operation.

By the way, in order to determine whether or not the sensor is functioning properly, it is important to check for changes in sensor characteristics caused by the temperature rise of the sensor itself as combustion begins (for example, if the sensor is made of an electrical resistor, it is important to If the change state is normal, it is determined that the sensor function is normal, and if the change state is abnormal, it is determined that the sensor function is abnormal. It is also possible to do this, but this is an indirect method of discrimination that involves looking at changes in sensor characteristics due to temperature rise, so there is a problem with reliability.

In this regard, the present invention uses a direct determination method that determines whether the sensor function is good or not, depending on whether the sensor properly detects the incomplete combustion state that actually occurs immediately after the ignition operation, and is therefore extremely reliable. Highly sexual.

〔Effect of the invention〕

As a result of the above, the sensor immediately after the start of the ignition operation can prevent incomplete combustion from continuing due to some reason due to starting combustion operation when there is a sensor problem such as sensor deterioration. It is now possible to reliably prevent equipment troubles due to lack of oxygen in the room, clogging, etc. due to the unexpected continuation of incomplete combustion by using safety functions based on accurate judgment of the quality of the function.
A combustion device with extremely excellent safety and equipment security has been created.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

Figure 1 shows the schematic configuration of a gas water heater, with a casing (1
) is equipped with a water tube-type water heating heat exchanger (2) and a heating gas burner (3) for it, and a hot water tap (4).
) to which the hot water supply pipe (5) from the heat exchanger (2) is connected.

A water flow switch (7) is installed in the water supply pipe (6) to the heat exchanger (2), and a flame rond (8) for detecting combustion flame is installed near the burner (3). The gas exhaust passages (9) are each provided with a sensor (10) for detecting the concentration of a combustible gas component (for example, -carbon oxide) in the exhaust combustion gas, and a gas valve (11) for intermittent fuel supply to the burner (3). ), and a control device (13) that automatically operates the burner ignition plug (12), are equipped with the following circuits (a) to (c).

(a) The water flow switch (7) accompanying the opening operation of the hot water tap (4)
), the gas valve (11) is opened and the ignition plug (12) is activated to ignite the burner (3), and the water flow switch (7) is activated when the tap (4) is closed. ) A circuit (13A) that closes the gas valve (11) based on the OFF operation of the burner (3) to extinguish the burner (3).

(b) After the ignition operation, based on the combustion flame detection by the flame rond (8), the gas valve (11) is kept open only when the combustion flame is detected to prevent the release of raw gas due to extinction. Prevention circuit (13B).

(c) A circuit (13C) that closes and operates the gas valve (11) based on the concentration of combustible gas components detected by the concentration detection sensor (10) when the detected concentration exceeds the set upper limit concentration (13C). ).

FIG. 2 shows a concentration detection sensor (10), which is equipped with a ceramic cylindrical body (15) inside a protective frame (14) formed of a stainless wire mesh.
3702 film-like sintered body (16) is pasted on the outer peripheral surface of ),
A film-like sintered body (16) in the longitudinal direction of the cylindrical body (15)
Electrodes 8g (17) are connected to both ends of the electrode.

In other words, it utilizes the fact that when the concentration of flammable gas components in the exhaust combustion gas that comes into contact with the S70□ film-like sintered body (16) increases, the electrical resistance value of the film-like sintered body (16) decreases. hand,
It is configured to detect the concentration of combustible gas components by measuring its electrical resistance value.

In the figure, (18) is an electric heater inserted through the ceramic cylindrical body (15), and the preheating action of the electric heater (18) causes S. 0□ By maintaining the temperature of the film-like sintered body (16) at a set temperature, stable concentration detection is performed.

For the control device (13), an incomplete combustion prevention circuit (
13C) for a set time (Δt) from the point of ignition operation, regardless of the concentration detected by the sensor (10) (i.e., the measured resistance value of the S A02 membrane sintered body (16)). The burner (3) is not required due to the incomplete combustion state (temporary decrease in the measured resistance value r) that always occurs immediately after the ignition operation, as shown in Figure 3. The structure is designed to prevent the fire from being extinguished.

In the figure, (rx) is the set standard resistance value corresponding to the set upper limit concentration of combustible gas component concentration, and incomplete combustion occurs when the measured resistance value (r) becomes smaller than the set standard resistance value (rx). The gas valve (11) is closed by the prevention circuit (13C).

On the other hand, whether or not the measured resistance value (r) became smaller than the set reference resistance value (rx) within the set time (ΔL) for preventing the incomplete combustion prevention circuit (13C) from shutting off the gas valve, i.e. A circuit (13E) for determining whether the concentration of combustible gas components exceeds the set upper limit concentration based on information from the sensor (10) is incorporated into the control device (13), and the determination circuit (13E) makes a determination. Based on the results, if the measured resistance value (r) does not become smaller than the set standard resistance value (rx) within the set time (Δt), the gas valve (11
) is prioritized over the incomplete combustion prevention circuit (13C), in other words, the circuit closes and operates regardless of the measured resistance value (r) at that time, and the measured resistance value (r) is closed within the set time (Δt). ) becomes smaller than the set reference resistance value (rx), the gas valve (
11) is maintained in the open state while prioritizing the closing operation by the incomplete combustion prevention circuit (13C), in other words, while making use of the incomplete combustion prevention function based on the judgment of the measured resistance value (r). 13F) is incorporated into the control device (13).

In other words, by using the incomplete combustion prevention state that always occurs immediately after ignition operation to self-diagnose whether or not the sensor (10) is functioning properly, Deterioration of the sintered body (16) and electrode wire (1)
7) or malfunction of the electric heater (18), etc., to prevent incomplete combustion from occurring unexpectedly.

FIG. 4 is a flowchart showing the overall control flow by the control device (engine 3).

[Another example]

Next, another embodiment of the present invention will be described.

Various types of sensors can be used as the sensor (10) for detecting the concentration of combustible gas components, and various combustible gases can be detected, such as carbon monoxide and hydrogen. .

Incomplete combustion prevention means (13C), time limit check circuit (13
0), determination means (13E), and security means (13F
) As for the specific configuration of each, various configuration changes are possible, such as configuring it with a sequence circuit or applying a microcomputer.

The fuel used in the burner (3) does not matter.

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

[Brief explanation of the drawing]

1 to 4 show embodiments of the present invention, FIG. 1 is a schematic overall structural diagram, FIG. 2 is a partially cutaway enlarged view of the sensor,
Figure 3 shows combustible gas in the combustion gas immediately after the ignition operation?
A graph showing changes in M and V, and FIG. 4 is a flowchart. (3)...Burner, (10)...Sensor, (11)...Valve mechanism, (13C)...
... Incomplete combustion prevention means, (130) ... Time limit check means, (13E) ... Discrimination means, (13
F)...Security means, (Δt)...Setting time.

Claims (1)

[Claims] Valve mechanism (11) that cuts off fuel supply to the burner (3)
and a sensor (10) for detecting the concentration of combustible gas components in the combustion gas from the burner (3), and when the concentration detected by the sensor (10) exceeds the set upper limit concentration, the valve mechanism (11) is provided with an incomplete combustion prevention means (13C) that automatically shuts off the burner (11), and a set time (Δt) is provided from the time of the ignition operation for the burner (3).
The combustion apparatus is provided with a time limit check means (13D) that prevents the incomplete combustion prevention means (13C) from shutting off the valve mechanism (11) regardless of the concentration detected by the sensor (10), Means (13E) is provided for determining whether or not the concentration detected by the sensor (10) exceeds the set reference concentration within the set time (Δt), and based on the determination result by the determining means (13E), the setting When the reference concentration is not exceeded, the valve mechanism (11) is operated to shut off the incomplete combustion prevention means (13C) at the lapse of the set time (Δt), and
When the set standard concentration is exceeded, after the set time (Δt) has elapsed, the valve mechanism (11) is maintained in a non-shutoff state while giving priority to the shutoff operation by the incomplete combustion prevention means (13C). Combustion equipment equipped with safety measures (13F).