JPS59100342A - Heating apparatus by hot air with oxygen-deficiency preventer - Google Patents

Abstract

PURPOSE:To raise safeness of a heating apparatus by stopping the combustion of fuel before lowering of xygen (O2) concentration for interruption of oxygen deficiency by a method in which the rotation number of a fan is reduced for every interval of fixed time period and the supply of fuel is interrupted at nearly 18% O2 concentration in a room where CO is not almost accumulated. CONSTITUTION:In an electronic control circuit 14, the fuel interrupter 16 of a fuel supplier 5 is opened or closed by the variation of the signals of a combustion sensor 7, and the number of rotation of a fan is reduced only for a time period necessary for interruption of oxygen deficiency at a fixed interval of time period by a timer function. When using a SnO2 oxide semiconductor sensor as a sensor 7, the rotation number of the fan is reduced, the amount of air is reduced temporarily, and the resistance value is abruptly varied before CO is not almost accumulated in a room at a nearly 18% O2 concentration in case where an air-deficient combustion occurs. The variation of the resistance is detected by the control circuit 14 to interrupt the fuel supply path 15.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an indoor open combustion appliance for general home heating using gas or oil as fuel, and particularly to a hot air heater equipped with an oxygen deficiency prevention device.

Conventional configuration and its problems In a hot air heater with an oxygen deficiency prevention device that utilizes resistance changes such as 5N02 and TiO2 or electromotive force changes of ZrO2, the burner burns to a low oxygen concentration so as not to generate CO. If so, there was a drawback that the degree of oxygen deficiency cutoff 02 would be low.

OBJECTS OF THE INVENTION The object of the present invention is to provide highly safe hot air heating i% that stops combustion before the oxygen deficiency cutoff 02 concentration becomes low.

Structure of the Invention The present invention reduces the rotational speed of the fan at regular intervals during normal combustion for the time necessary to cut off oxygen deficiency, and temporarily changes the ratio of air and fuel to prevent the room from being too low in oxygen. This relates to an open combustion hot air heater 2g, which is an example of an oxygen deficiency prevention device that shuts off the fuel supply path and stops combustion before CO is accumulated indoors.

Embodiment FIG. 1 shows an embodiment of the present invention, in which 1 is the appliance body, 2 is a fan, 3 is a ventilation guide, 4 is a heat shield case, and 6
6 is a hot air outlet, 6 is a combustion burner, and 6 is a combustion detection sensor. The part forming the exhaust outlet 9 of the combustor 8 is
The rear plate 11 is arranged so that the convection air 10 does not enter the combustion chamber 8 and a negative pressure corresponding to the rotation speed of the fan 20 is generated in the combustion chamber 8.
is the provision. Combustion exhaust gas 1.2 and convection air 10 are mixed to form warm air 13 and discharged into the room.

Reference numeral 14 denotes an electronic control circuit that opens and closes a fuel cutoff device 16 of a fuel supply path 15 based on a change in a signal from a sensor 7.

Partial supply to the burner is carried out through a nozzle 17, and primary air 18 is sucked in by the venturi effect of fuel jetted from the nozzle and the effect of negative pressure in the combustion chamber by a fan. When the burner flame 19 is an all-air type burner, complete combustion occurs only with the above-mentioned primary air 18, and secondary air is not necessary. In the case of a Bunsen type burner, a flame 19 is formed by, in addition to the above-mentioned primary air, secondary air 21 from a hole 20 at the bottom of the combustion chamber, primary air 18, and fuel. The electronic control circuit 14 also has a timer function that reduces the number of fan rotations for an amount of time (usually within 1 minute) that is not necessary to cut off oxygen deficiency at fixed time intervals (usually about 10 minutes).

FIG. 2 shows the relationship between indoor 02 concentration, sensor resistance value, and indoor accumulated CO concentration when a 5n02 oxide semiconductor sensor is used. As shown in FIG. 2, when the fan rotation speed is normal combustion, the resistance value of the 5n02 sensor suddenly changes when the 02 concentration is close to 16% and a considerable amount of CO has accumulated in the room. In addition, if the rotation speed of the fan is reduced to temporarily reduce the air agitation and combustion is performed due to lack of air, the 02 concentration 1
At close to 8%, the resistance of the 5n02 sensor suddenly changes before much CO has accumulated in the room. This change in resistance is captured by the first control circuit and applied to the fuel supply path! cut off

FIG. 3 shows the characteristics obtained using an electromotive force type sensor using ZrO2. In this case as well, the above 5n02
The same thing can be said when using .

Effects of the Invention If the rotation speed of the fan is reduced at regular intervals as in the present invention, the l supply path will be cut off at around 18% indoor temperature, when almost no CO is accumulated indoors. Since combustion stops, it can be said to be an extremely safe open combustion hot air heater.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a warm air heater with an oxygen deficiency prevention device that is an embodiment of the present invention, and Fig. 2 is a characteristic diagram when the same oxide semiconductor 5n07 sensor is used, and the solid line is the conventional characteristic 2. The dotted line indicates the characteristics of the present invention, and FIG. 3 is a characteristic diagram using a ZrO2 sensor as the 5n02 sensor. 6...Burner, 7...Sensor, 8...
...Combustion chamber, 14...Electronic control circuit, 16...
...Fuel cutoff device. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] Negative pressure is generated in the combustion chamber by the rotation of the fan, and the mixture ratio of air and fuel is varied.In addition, an oxide semiconductor sensor is installed in the combustion chamber whose signal changes depending on the combustion state, and this prevents oxygen deficiency at regular intervals. A hot air heater with an oxygen deficiency prevention device that reduces the fan rotation speed compared to normal combustion for a sufficient period of time for the device to operate, and shuts off the fuel supply path while the indoor CO concentration is low.