JPS6217519A - Combustion safety device - Google Patents

Abstract

PURPOSE:To enable reliable detection of a set value of Co gas concentration in exhaust gas through elimination of a change in resistance due to a change in the exhaust gas temperature of a gas sensor, by a method wherein a thermostatic device which keeps the temperature of a gas sensor at a constant value is mounted to a heat apparatus. CONSTITUTION:A vent passage 13, having the one end connected to a base part 4a of a gas sensor 4 facing on the outside of an exhaust passage 3 and the other end connected to an exhaust cylinder serving as an exhaust passage 3, is provided to a thermostatic device. A damper 14, the opening of which is changed through detection of the temperature of the base part 4a of the gas sensor 4, is located in the vent passage 13. The opening of the damper 14 regulates an amount of vent air flowing through the vent passage 13, i.e. an intake air amount, exerted on the base part 4a of the gas sensor 4, and causes maintenance of the temperature of the gas sensor 4 at a normal value and detection of correct Co gas concentration.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of industrial application) The present invention relates to a combustion safety device in a thermal appliance such as a gas bath kettle.

(Prior art) A semiconductor gas sensor is placed in the exhaust path of a thermal device having a burner, and when the CO gas concentration in the exhaust gas from the burner is detected to be higher than a set value, an electromagnetic gas sensor is placed in the gas supply path to the burner. For example, a combustion safety device that closes a valve and heats the semiconductor gas sensor to a temperature at which CO gas can be detected using the heat contained in the exhaust gas from the burner is as follows:
It is known from Japanese Unexamined Patent Publication No. 60-2CO24.

(Problems to be Solved by the Invention) However, the resistance value of this semiconductor gas sensor changes significantly not only depending on the OO gas concentration but also depending on the temperature as shown in FIG.

0 or 1 Thermal equipment power for bath kettles and water heaters; for thermal equipment whose exhaust temperature changes depending on the usage conditions, such as those installed side by side, it is inconvenient that the correct Oo gas concentration cannot be detected. There is.

(Means for solving the problems) The present invention is intended to solve the following problems,
When a semiconductor gas sensor (4) is placed in the exhaust path (3) of a thermal device (2) having a burner and detects that the CO gas concentration in the exhaust gas from the burner exceeds the set value, gas is supplied to the burner. A solenoid valve (6) interposed in the passage (5) is closed, and the semiconductor gas sensor (4) is connected to the burner T.
1), the heat equipment (2) is equipped with a constant temperature device (7) that keeps the temperature of the sensor (4) at approximately constant temperature. ).

(Function) When hiding, the sensor (4) is heated by the constant temperature device (7).
Since the temperature is kept constant, resistance changes due to temperature changes are eliminated, and the opening and closing of the solenoid valve (61) can be controlled with accurate CO concentration.

In fact, the temperature was maintained at a constant level of about 1 CO°C to 130°C, where the resistance change of the sensor (4) with respect to temperature changes is relatively small.

(Embodiment) To explain an embodiment of the present invention with reference to the drawings, what is shown in FIG. 1 is an embodiment of a bath pot that can be used as a thermal device (2) having a burner (1) and whose capacity can be switched into two stages. te, burner (
1) The upper hood (
A semiconductor gas sensor (
4), the exhaust gas from the burner (1) heats the gas sensor (4) to a temperature at which CO gas can be detected, and the CO gas concentration in the exhaust gas exceeds the set value. Detecting this, the solenoid valve (6) interposed in the gas supply path (5) of the burner (1) is closed;
In addition, the temperature of the sensor (4) is maintained at a substantially constant temperature regardless of the strength of the exhaust temperature. The valves are installed separately in two gas supply paths (5a) and (5b) that branch on the downstream side of the electromagnetic valve (6) of the gas supply path (5), and one gas supply path (5a) is installed separately. ) is provided with an on-off valve, and when the on-off valve is closed, the combustion state is switched between two stages: weak, in which only the two burners (11) are activated, and strong, in which only the two burners (11) are opened. (7)
The burner (1) controlled by the on-off valve C1G
A ventilation pipe αυ is provided so that one end faces one gas supply port of the semiconductor gas sensor (4) and the other end faces the base (4a) of the semiconductor gas sensor (4), and the ventilation pipe (Ill is connected to the opening/closing valve (IG) The on-off valve a'at- opened and closed.

In this case, the gas sensor ( 4) generates an air flow that sucks air near the base of the base (4a).
t-What is the case of weak combustion even during strong twist firing when cooling and exhaust gas temperature becomes high? At the same constant temperature, the gas sensor (4) t-
can be kept.

In the embodiment shown in Fig. wc2 and Fig. 3, a forced exhaust type thermal equipment (2) is shown in which a bath pot A is attached to a water heater B for Java.
The exhaust gas temperature changes depending on whether it is used or used together, and according to this, the exhaust gas temperature of the heat equipment (2)
The resistance value of the gas sensor (4) facing the detection part (4b)i also changes, making it impossible to correctly detect the Oo gas concentration.

In order to solve this problem, the exhaust passage (
3) A ventilation path (13) is provided, one end of which is opened at the base (4a) of the gas sensor (4) facing outside, and the other end is connected to an exhaust pipe serving as an exhaust path (3). , a damper (one trench) whose opening degree changes by detecting the temperature of the base (4a) of the gas sensor (4), and depending on the opening degree of the damper I,
The amount of air flowing through the ventilation path (13) and therefore the gas sensor (4)
) of the base (4a) K acting on the intake air fflt- was regulated, thereby keeping the temperature of the gas sensor (4) approximately constant.

In this case, when the base (4&) of the gas sensor (4) is in a state of 1CO°C or less as shown in Fig. 4, the damper α is completely closed to actively heat the gas sensor (4),
When the temperature is between 130°C and 130°C, it is half-open, and then the temperature is 130°C.
In the above, this was fully opened and the base (4a) of the gas sensor (4) was actively cooled so that the gas sensor (4) was always maintained at a substantially constant temperature.

Note that the air flow in the air passage α3 is caused by draft accompanying natural exhaust, but it is even better if it is forcibly caused by a fan provided in the exhaust pipe. In the above embodiment, cold air was flowed through the base (4&) of the gas sensor (4) to keep the entire gas sensor (4) at a constant temperature. Alternatively, the gas sensor (4) may be kept at a constant temperature.

(Effects of the Invention) As described above, according to the present invention, since the thermal equipment is provided with a constant temperature device that keeps the temperature of the gas sensor at a substantially constant temperature, resistance changes due to changes in the exhaust gas temperature of the gas sensor are eliminated, and the temperature of the exhaust gas is reliably maintained. This has the effect of providing a safety device that can detect the set value of the CO gas concentration.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a side view;
The IJZ diagram is a cutaway side view of another embodiment, FIG. 5 is an enlarged sectional view of the main part, and FIG. 4 is a diagram showing the characteristics of the semiconductor gas sensor. (1)... Burner (2)... Thermal equipment (
3) Exhaust path (4) Semiconductor gas sensor (5) Gas supply path (6) Solenoid valve (7) Constant temperature device patent applicant Lin Sui Co., Ltd. 2 people

Claims (1)

[Claims] 1. A semiconductor gas sensor is placed in the exhaust path of a thermal device having a burner, and when a CO gas concentration in the exhaust gas from the burner is detected to be higher than a set value, the semiconductor gas sensor is placed in the gas supply path to the burner. In a device that closes a solenoid valve and heats the semiconductor gas sensor to a temperature at which CO gas can be detected using the heat contained in the exhaust gas from the burner, the temperature of the gas sensor is set in the thermal device. A combustion safety device that is equipped with a constant temperature device that maintains a constant temperature. 2. The combustion safety device according to claim 1, wherein the constant temperature device is a ventilation device that ventilates the base of the sensor when the exhaust gas temperature is high. 3. The combustion safety device according to claim 4, wherein the constant temperature device is a ventilation device that increases the amount of ventilation to the base of the sensor in response to a rise in the temperature of the exhaust gas.