JPS6133406Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a gas combustion device with an electromagnetic safety valve.
In more detail, the electromagnetic safety valve that opens and closes the gas supply passage to the pilot burner and main burner.
The present invention relates to a gas combustion apparatus with an electromagnetic safety valve that is operated by superpower generated in a first sensor disposed within the flame of the pilot burner and a second sensor disposed within the flame of the main burner.

[Prior art]

Generally, this type of gas combustion device employs a thermocouple as the first sensor and an oxygen concentration difference sensor as the second sensor, with both sensors built into separate circuits, and is configured so that when incomplete combustion occurs in the main burner, an electromotive force is generated in the oxygen concentration difference sensor due to the oxygen concentration difference caused by CO, and this electromotive force acts on the thermocouple side circuit to close the electromagnetic safety valve and stop the gas supply to both burners. For this reason, in conventional gas combustion devices, if an abnormality occurs in the oxygen concentration difference sensor itself, which is the second sensor,
Unless there is an abnormality in the circuit including the thermocouple, even if incomplete combustion occurs in the main burner, the electromagnetic safety valve cannot be closed and incomplete combustion will continue, and in this respect it cannot be said that safety (fail-safety) is sufficient.

In order to deal with such problems, the applicant filed a
-125439 (Utility Model Publication No. 60-42264) has been filed for the following gas combustion device with an electromagnetic safety valve. In other words, this device is activated by the electromotive force generated in a thermocouple placed within the flame of the pilot burner, and after the main burner is ignited, it is activated by the electromotive force generated in the oxygen concentration difference sensor placed within the flame. An electromagnetic safety valve is provided to keep gas supply passages to both burners open, and the oxygen concentration difference sensor is disposed at a location that generates normal combustion electromotive force in the flame of the main burner and does not cause abnormal combustion electromotive force. connected in series to the thermocouple;
A normally closed switch that is opened in conjunction with the gas supply operation to the main burner is connected in parallel to the oxygen concentration difference sensor in a series connection circuit of the thermocouple, the oxygen concentration difference sensor, and the electromagnetic coil of the electromagnetic safety valve. It is characterized by being connected to.

[Problem that the invention attempts to solve]

By the way, the oxygen concentration difference sensor used in the gas combustion device described above is equipped with an oxygen concentration cell made of an oxygen ion conductive solid electrolyte such as zirconia and electrode layers such as porous platinum coated on both sides. As a result, the internal resistance decreases from about 100 MΩ to about 20Ω, and when a difference in oxygen concentration occurs between the two electrode layers after reaching a predetermined temperature, an electromotive force of 700 mV to 800 mV is generated. On the other hand, thermocouples used in conjunction with oxygen concentration difference sensors usually have an internal resistance of about 10 mΩ and an electromotive force of about 25 mV when heated. Therefore, there is a large difference in the characteristics of these two, and it is necessary to use a special electromagnetic safety valve to use both of them together.

Therefore, the present invention replaces the thermocouple with a generator that generates the same level of electromotive force as the oxygen concentration difference sensor, thereby making this type of gas combustion device fail-safe without using the special electromagnetic safety valve described above. It is about improving sexuality.

[Means for solving problems]

In order to deal with such problems, the present invention provides a gas combustion apparatus with an electromagnetic safety valve of this type.
An oxygen concentration difference sensor is adopted as the sensor, and this second sensor is disposed at a location in the flame of the main burner that does not generate an electromotive force during normal combustion but generates an electromotive force during abnormal combustion, and A power generation element that generates the same level of electromotive force as the second sensor is used as the sensor, and the first sensor is disposed at a location where normal combustion electromotive force is generated within the flame of the pilot burner. The second sensor is connected in series with reverse characteristics, and a normally closed switch that is opened in conjunction with the gas supply operation to the main burner is connected to the series connection circuit of the first sensor, the second sensor, and the electromagnetic safety valve. The electromagnetic safety valve is connected in series to the second sensor, and opens the gas supply passage via the electromagnetic safety valve by the electromotive force generated in the first sensor, and when an abnormality occurs in the second sensor, the electromagnetic safety valve is characterized in that the gas supply is stopped by closing the gas.

[Function and effect of the idea]

According to this configuration, when abnormal combustion occurs in the main burner, the electromotive force generated in the second sensor closes the electromagnetic safety valve, and when an abnormality occurs in the second sensor during combustion in the main burner, the electromotive force generated in the first sensor is closed. The electric current is cut off and the electromagnetic safety valve is closed. Therefore, the fail-safety of the gas combustion device is sufficiently ensured. According to this configuration, it is possible to employ a power generating element that generates the same level of electromotive force as the second sensor, which is the oxygen concentration difference sensor, as the first sensor.
There is no need to use a special electromagnetic safety valve that can be used in combination with a thermocouple and oxygen concentration difference sensor.

〔Example〕

Figure 1 shows a gas combustion device with an electromagnetic safety valve (hereinafter sometimes simply referred to as a gas combustion device) according to the present invention.
In this gas combustion apparatus, a pilot gas passage 13 is branched from a main gas passage 12 which is a gas supply passage to a main burner 11. Further, in the main gas passage 12, an electromagnetic safety valve 20 is interposed at an upstream side of the pilot gas passage 13, and an automatic on-off valve 30 is interposed at a downstream side of the pilot gas passage 13. The electromagnetic safety valve 20 includes an electromagnet 21, an operating rod 24 having a suction plate 22 and a valve body 23, and a spring 26 that urges the operating rod 24 upward in the figure to seat the valve body 23 on the valve seat 25. When the operating rod 24 is pushed against the spring 26, the main gas passage 12
The upstream side of the electromagnet 21 is opened, and when a magnetic force is generated in the electromagnet 21 in this state, the operating rod 24 is attracted and held. Moreover, the automatic opening/closing valve 30 is
It includes an operating rod 31 connected to a diaphragm of a hydraulic response device 15 installed in the water supply passage 14, and a spring 33 that urges the operating rod 31 to the right in the figure to seat the valve body 31a on the valve seat 32. ,
Main gas passage 12 by supplying water to heat exchanger 16
It is configured to open the downstream side of the

Therefore, the electromagnet 21 in the electromagnetic safety valve 20
As shown in FIG. 2, the electromagnetic coil 21a has one end connected to the (+) pole side of the first sensor 41 disposed within the flame of the pilot burner 17, and the other end connected to the flame of the main burner 11. It is connected to the (+) pole side of a second sensor 42 disposed inside. The first sensor 41 is a thermoelectric power generation element made of a sintered body of iron, silica, etc. that utilizes the Seebeck effect. When heated, the internal resistance decreases from about 5Ω to about 0.4Ω, generating an electromotive force of about 200mV. Also,
The second sensor 42 is a flat oxygen concentration difference sensor that forms an oxygen concentration battery by depositing electrode layers such as porous platinum on both sides of an oxygen ion conductive solid electrolyte such as zirconia. is about
It decreases from 100MΩ to about 20Ω and 700mV when there is a difference in oxygen concentration between both electrodes during heating.
Generates an emf of ~800mV. The oxygen concentration difference sensor 42 is disposed so as to be located within the outer flame of the flame during normal combustion of the main burner 11. During normal combustion, both sides of the sensor are surrounded by the outer flame and no electromotive force is generated, resulting in incomplete combustion. During combustion, the inner flame extends and contacts the bottom surface of the sensor, generating an electromotive force due to the difference in oxygen concentration between the inner and outer flames. (-) of this oxygen concentration difference sensor 42
The pole side is connected to the (-) pole side of the thermoelectric generator 41, and the thermoelectric generator 41 and the oxygen concentration difference sensor 42
and are connected in series with reverse characteristics. On the other hand, an operating piece 31b is fixed to the operating rod 31 of the automatic on-off valve 30, and a normally closed switch 43 is provided which is opened and closed by the operating piece 31b. This normally closed switch 43 is configured to be opened when the automatic on-off valve 30 opens the main gas passage 12 by water supply to the heat exchanger 16.
a, thermoelectric generating element 41 and oxygen concentration difference sensor 4
An oxygen concentration difference sensor 42 is connected between the two series connected circuits.
are connected in parallel. Further, an oxygen concentration difference sensor 42 is connected between the series-connected circuits described above.
A capacitor 44 is connected in parallel to the normally closed switch 43.

In the gas combustion device configured in this way,
When not in use, the main gas passage 12 is closed by the electromagnetic safety valve 20 and the automatic opening/closing valve 30, and the normally closed switch 43 is closed. In this state,
When the gas main valve (not shown) is opened and the operating rod 24 of the electromagnetic safety valve 20 is pushed against the spring 26, the upstream side of the main gas passage 12 is opened, gas is supplied to the pilot burner 17 through the pilot gas passage 13, and at the same time An igniter (not shown) operates to ignite the pilot burner 17. As a result, the thermoelectric generating element 41 is heated and an electromotive force is generated, and the thermoelectric generating element 41 and the electromagnetic coil 21a
Then, the closed circuit of the normally closed switch 43 is energized, and the electromagnet 21 is excited. As a result, the operating rod 24 of the electromagnetic safety valve 20 is attracted to the electromagnet 21,
The main gas passage 12 is kept open. Note that during this time, since the internal resistance of the oxygen concentration difference sensor 42 is large, almost no current is applied to the closed circuit of the thermoelectric generating element 41, the electromagnetic coil 21a, and the oxygen concentration difference sensor 42. Next, when water is supplied to the heat exchanger 16, the automatic opening/closing valve 30 operates to open the downstream side of the main gas passage 12, and gas is supplied to the main burner 11. Therefore, the main burner 11 is ignited by the pilot burner 17, the oxygen concentration difference sensor 42 is heated, and its internal resistance value is reduced. However, no electromotive force is generated in the oxygen concentration difference sensor 42. Further, the normally closed switch 43 is opened at the same time as the automatic opening/closing valve 30 is operated, but the thermoelectric power generating element 41 and the electromagnetic coil Electromagnet 21 is excited by the circuit of 21a and capacitor 44, and main gas passage 12 is kept open. During this time, the internal resistance value of the oxygen concentration difference sensor 42 decreases to about 20Ω, and after that, the electromotive force generated in the thermoelectric generator 41 energizes the closed circuit of the thermoelectric generator 41, the electromagnetic coil 21a, and the oxygen concentration difference sensor 42. The main gas passage 12 is kept open. Further, when the water supply is stopped in order to extinguish only the main burner 11, the automatic on-off valve 30 is closed and the normally closed switch 43 is closed. As a result, the electromotive force generated in the thermoelectric generating element 41 energizes the closed circuit of the thermoelectric generating element 41, the electromagnetic coil 21a, and the normally closed switch 43 again, and the main gas passage 12 is held open and the pilot burner 17
maintains only ignition. Note that the delay in the closing operation of the normally closed switch 43 that occurs at this time is compensated for by the discharge of the capacitor 44.

By the way, in the gas combustion apparatus, when incomplete combustion occurs in the main burner 11, an electromotive force is generated in the oxygen concentration difference sensor 42, and this electromotive force causes the thermoelectric generating element 41, the electromagnetic coil 21a, and the oxygen concentration difference sensor to A current flows in the closed circuit 42 in the opposite direction to the current due to the electromotive force of the thermoelectric generating element 41 . Therefore, the electromagnet 21 becomes de-energized,
Since the operating rod 24 of the electromagnetic safety valve 20 cannot be held by suction, the main gas passage 12 is closed, and subsequent incomplete combustion is prevented from continuing.

In this way, in the gas combustion apparatus, the electromagnetic safety valve 20 is opened by the electromotive force generated in the thermoelectric generating element 41 via the oxygen concentration difference sensor 42, which does not generate an electromotive force during normal combustion in the main burner 11.
It is configured to keep the main gas passage 12 open. Therefore, when an abnormality occurs in the oxygen concentration difference sensor 42 itself, for example, when the internal resistance value does not decrease even when heated, or when the internal resistance becomes abnormally large, the oxygen concentration difference sensor 42
Since it is impossible to open the electromagnetic safety valve 20 via the main gas passage 12 and the main gas passage 12 is closed, it is extremely safe. In addition, in this gas combustion device, the thermoelectric generating element 41, which has a larger internal resistance and electromotive force than a thermocouple, is used as the first sensor, so it can be used in combination with the oxygen concentration difference sensor 42, which is used as the second sensor. The degree of freedom in selecting the electromagnetic safety valve 20 is increased. Therefore, in the gas combustion apparatus, there is no need to use a special electromagnetic safety valve that can be used in conjunction with a thermocouple.

The gas combustion apparatus employs a normally closed switch 43 that is opened simultaneously with the ignition of the main burner 11, and a condenser 44 to compensate for the time difference until the oxygen concentration difference sensor 42 becomes active. However, instead of the normally closed switch 43, a heat-sensitive reed switch or a delay relay reed switch that opens after a predetermined time delay after the ignition operation may be used, and instead of the thermoelectric generating element 41, a heat-sensitive reed switch or a delay relay reed switch that opens after a predetermined time delay may be used. An oxygen concentration difference sensor similar to the difference sensor 42 may be employed. When an oxygen concentration difference sensor is adopted as the first sensor, the oxygen concentration difference sensor 42 which is the second sensor
In contrast, it is necessary to arrange the fuel in the flame of the pilot burner 17 so as to generate an electromotive force during normal combustion of the pilot burner 17. Furthermore, the present invention provides an electromagnetic safety valve for opening and closing gas supply passages to the pilot burner and the main burner, which is provided in a first sensor disposed within the flame of the pilot burner and a second sensor disposed within the flame of the main burner. It can be applied to various types of gas combustion devices with electromagnetic safety valves that are operated by electromotive force.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of a gas combustion device according to the present invention, and FIG. 2 is a control circuit diagram of an electromagnetic safety valve in the gas combustion device. Explanation of symbols, 11... Main burner, 12...
Main gas passage, 13...pilot gas passage,
17... Pilot burner, 20... Electromagnetic safety valve, 21... Electromagnet, 30... Automatic opening/closing valve, 41
...thermal power generation element, 42 ... oxygen concentration difference sensor,
43...Normally closed switch.

Claims (1)

[Scope of utility model registration request] An electromagnetic safety valve that opens and closes a gas supply passage to a pilot burner and a main burner is connected to a first sensor disposed within the flame of the pilot burner and a second sensor disposed within the flame of the main burner. In the gas combustion device with an electromagnetic safety valve, the second
An oxygen concentration difference sensor is adopted as the sensor, and this second sensor is disposed in a part of the flame of the main burner that does not generate superpower during normal combustion but produces superpower during abnormal combustion,
A power generating element that generates the same level of superpower as the second sensor is adopted as the first sensor, and the first sensor is disposed at a part that produces superpower during normal combustion in the flame of the pilot burner, The second sensor is connected to the first sensor in series with reverse characteristics, and a normally closed switch that is opened in conjunction with the gas supply operation to the main burner is connected to the first sensor, the second sensor, and the electromagnetic safety valve. Connected in parallel to the second sensor in a series connection circuit, the superpower generated in the first sensor opens the gas supply passage via the electromagnetic safety valve, and an abnormality occurs in the second sensor. 1. A gas combustion apparatus with an electromagnetic safety valve, wherein the electromagnetic safety valve is closed to stop gas supply when the electromagnetic safety valve is activated.