JPH0617069Y2 - Incomplete combustion detector - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an incomplete combustion detection device for detecting an incomplete combustion gas by installing a hot wire type semiconductor sensor in an atmosphere of exhaust gas of a combustor. is there.

[Conventional technology]

Conventionally, an incomplete combustion detection device incorporating a hot wire semiconductor sensor in which a metal oxide semiconductor is supported on a hot wire is known, but in this case, the hot wire semiconductor sensor is integrated with other circuits in a housing. It is housed and installed in the room,
Sufficient electric power was applied to the hot wire of the hot wire semiconductor sensor to heat the semiconductor.

[Problems to be solved by the invention]

By the way, the above-mentioned incomplete combustion detection device needs to supply sufficient electric power to the heating wire. Further, since the SN ratio is low when the gas concentration is low and the hot wire type semiconductor sensor is in the room, the incomplete combustion gas contained in the exhaust gas generated from the combustor must be discharged into the room. There is a problem that early detection cannot be performed because it is not detected.

The present invention has been made to solve the above-mentioned problems, in which the hot wire semiconductor sensor is heated by the exhaust gas to save power, and the incomplete combustion gas can be detected early. An object is to provide a detection device.

[Means for solving problems]

The incomplete combustion detection device according to the present invention is a hot wire semiconductor sensor provided in an atmosphere of exhaust gas in which a metal oxide semiconductor is carried on a hot wire made of a metal wire or a noble metal alloy wire that is hard to oxidize at a high temperature, and this hot wire. Type semiconductor sensor is self-heated to keep the temperature of the exhaust gas atmosphere and the heating type semiconductor sensor at a predetermined temperature higher than the temperature of the exhaust gas atmosphere, and a resistance change of the hot wire type semiconductor sensor. A resistance value change detecting means for detecting is provided.

[Action]

In this invention, the hot-wire type semiconductor sensor is heated and held at a predetermined temperature by the heated exhaust gas and the energizing means. Then, the resistance value of the hot wire semiconductor sensor is changed by contacting the heated metal oxide semiconductor with the exhaust gas of incomplete combustion, and the exhaust gas is detected by the resistance value change detecting means.

〔Example〕

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, in which a flue 1 is provided in a combustor such as a water heater (not shown). Exhaust gas 2 in the flue 1 is generated by combustible gas such as city gas and propane gas burned in a combustor. Reference numeral 3 is a Wheatstone bridge circuit, which in this case serves both as an energizing means and a resistance value change detecting means.
S is a hot-wire type semiconductor sensor connected to one side of the Wheatstone bridge circuit 3, and is a combustible gas contained in the exhaust gas 2 in the flue 1 and is incomplete. Immediately detect combustion gases. R ₁ is a hot wire of the hot wire semiconductor sensor S. Since the hot wire R ₁ is used at a high temperature, it is made of a metal wire or a noble metal alloy wire which is hard to be oxidized at a high temperature. S _e is a metal oxide semiconductor supported on the hot wire R ₁ , R ₂ , R ₃ and R ₄ are resistors, E is a power supply, and M is incomplete combustion contained in the exhaust gas 2. It is an indicator that detects the concentration of gas.

The incomplete combustion detection device configured as described above is 100
The metal oxide semiconductor _Se is heated by the flow of the exhaust gas 2 and the heating filament R ₁ that are heated to ˜200 ° C. By the way, when the gas burner of the heater disappears, the flammable gas leaks, and the fresh air supply amount is insufficient, the flammable gas and the incompletely combusted gas 2 are mixed and discharged into the flue 1. For this reason, the flammable gas or the incompletely combusted gas in the exhaust gas 2 comes into contact with the metal oxide semiconductor S _e and reacts therewith to lower the resistance value of the heated metal oxide semiconductor S _e. Since the bridge circuit 3 is out of balance, the indicator M shakes to indicate that flammable gas has been detected.

As described above, since the hot wire semiconductor sensor S is used at a predetermined high temperature, the power E consumes less electric power for heating.

The hot wire semiconductor sensor S has a small shape and can be mounted anywhere, and in order to withstand a temperature of 200 ° C. or higher, the base insulator is made of glass or ceramic instead of conventional synthetic resin. Use the one formed in. The hot wire semiconductor sensor S is installed in the flue 1
The exhaust gas 2 is not limited to the above, and may be in the atmosphere of the exhaust gas 2.

[Effect of device]

As described above, the present invention relates to a hot wire semiconductor sensor provided in an atmosphere of exhaust gas in which a metal oxide is supported on a hot wire made of a metal wire or a noble metal alloy wire that is difficult to oxidize at high temperature, and the hot wire semiconductor sensor. A self-heating means for keeping the heating type semiconductor sensor at a predetermined temperature higher than the temperature in the atmosphere of the exhaust gas together with the temperature in the atmosphere of the exhaust gas, and a resistor for detecting a change in resistance value of the hot wire type semiconductor sensor. Since the value change detecting means is provided, the power consumption used for heating the hot wire semiconductor sensor can be small, and the power can be saved. Further, since the hot wire semiconductor sensor is provided in the exhaust gas atmosphere, the output becomes larger than that when the exhaust gas exhausted into the room is detected.
As the N ratio becomes large, the state of incomplete combustion of exhaust gas can be detected early. Since the hot wire semiconductor sensor is maintained at a predetermined temperature by heating with exhaust gas and self-heating, it is optimal for placing a hot wire semiconductor sensor self-heated to a predetermined temperature in exhaust gas as in the conventional case. There is an advantage that it is not heated to a high temperature deviating from the gas sensitivity, and there is no problem of deterioration of the metal oxide due to this.

[Brief description of drawings]

The drawing is a block diagram of an incomplete combustion detection device showing an embodiment of the present invention. In the figure, 1 is a flue, 2 is an exhaust gas, 3 is a Wheatstone bridge circuit, S is a hot wire semiconductor sensor, S _e is a metal oxide semiconductor, R ₁ is a hot wire, and R ₂ , R ₃ and R _{4 are.} Is a resistor, E
Is a power source, and M is an indication type.

Claims (1)

[Scope of utility model registration request] 1. A hot wire semiconductor sensor provided in an atmosphere of exhaust gas in which a metal oxide semiconductor is supported on a hot wire made of a metal wire or a noble metal alloy wire that is difficult to oxidize at high temperature, and the hot wire semiconductor sensor is self-heated. An energizing means for keeping the hot wire semiconductor sensor at a predetermined temperature higher than the temperature in the atmosphere of the exhaust gas together with the temperature in the atmosphere, and a resistance value change detecting means for detecting a resistance value change of the hot wire semiconductor sensor. An incomplete combustion detection device characterized by being provided with.