JPS5851551Y2 - Gas water heater with safety device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a gas water heater equipped with a safety device and equipped with an oxygen concentration sensor.

Various proposals have been made to detect oxygen deficiency conditions by inserting an oxygen concentration sensor into the pilot flame (or main burner flame) and utilizing the lift phenomenon of the pilot flame due to oxygen deficiency in the atmosphere, but this idea is the main one. An oxygen concentration sensor is inserted into the combustion chamber of the burner to immediately detect incomplete combustion caused by a lack of oxygen in the combustion chamber and a decrease in oxygen concentration due to clogging of the heat exchanger fins. Safety measures such as closing the door have been taken.

One embodiment will be described below with reference to the drawings.

In the drawings, reference numeral 1 denotes an inner shell equipped with a heat exchanger A on the upper side, and a test tube-shaped oxygen concentration sensor 2 is attached to the upper side of the inner shell with its tip sealed portion 4 facing into the combustion chamber 3. The base end opening 5 of the oxygen concentration sensor 2 is configured to be open to the outside air.

The oxygen concentration sensor 2 has a structure in which porous platinum electrode plates are stretched on the inner and outer surfaces 2 b and 2 b' of an oxygen ion conductive solid electrolyte 2 a such as a zirconia element.

6°6' is a lead wire, 7 is a main burner, a is its flame, 8 is a power supply pipe, and 9 is a hot water outlet pipe.

In the above configuration, during normal combustion (oxygen concentration 21%),
The sealed end portion 4 of the oxygen concentration sensor 2 is surrounded by the exhaust gas of the flame a of the main burner 7, but the excess oxygen in the combustion chamber 3 is larger than the theoretical amount of oxygen required for combustion in the main burner 7.
Since the oxygen concentration sensor 2 is supplied to both the inner and outer surfaces 2
The difference in oxygen concentration between b and 2b' is relatively small, and the electromotive force is also relatively small.

When the oxygen concentration in the atmosphere decreases to around 18% and becomes oxygen deficient, the amount of oxygen supplied in the combustion chamber 3 decreases, resulting in incomplete combustion and increased generation of carbon monoxide gas. The oxygen concentration of the oxygen concentration sensor 2b' becomes extremely low, resulting in a large oxygen concentration difference between the inner and outer surfaces 2b and 2b' of the oxygen concentration sensor 2, and a large electromotive force can be extracted from the lead wires 6 and 6'.

Next, if the fins of heat exchanger A become clogged, incomplete combustion will occur, so a large electromotive force can be obtained from the lead wires 6, 6', as in the case of oxygen deficiency.

Safety can be improved by utilizing this characteristic of increasing electromotive force to operate and close all the magnetic valves provided in the main gas passage.

As described above, in this invention, since the oxygen concentration sensor 2 is installed at a position distant from the flame a, it is more effective during incomplete combustion and normal combustion than when it is installed in contact with the flame a or inserted into the flame a. The generated electromotive force can be increased, and oxygen deficiency and fin clogging of the heat exchanger A can be stably detected without being affected by the shape of the flame a, particularly the elongation of the flame a.

Furthermore, this design has a very simple structure in which a test tube-shaped oxygen concentration sensor is placed inside the combustion chamber of the inner shell, and since a large electromotive force is generated when there is a lack of oxygen or the fins are clogged, incomplete combustion can be accurately detected and gas It is extremely useful in practical use because it allows safety measures such as stopping the supply of

[Brief explanation of drawings]

The drawing is a longitudinal sectional front view showing an embodiment of this invention. A... Heat exchanger, 1... Inner shell, 2...
...Oxygen concentration sensor, 3...Combustion chamber, 4.
...Tip sealing part, 5...Proximal opening.

Claims (1)

[Scope of utility model registration request] A test tube-shaped oxygen concentration sensor 2 is installed at a suitable location in the inner shell 1 having the heat exchanger A at the top, with its tip sealed portion 4 facing into the combustion chamber 3, and the proximal opening 5 of the sensor 2 is connected to outside air. A gas water heater with a safety device that is characterized by an open interior.