JPH0140042Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a semiconductor gas sensor used in a gas leak alarm for home or business use.

Conventional configuration and problems thereof Conventionally, this type of gas sensor has been configured as shown in FIG. In the figure, reference numeral 1 denotes a base made of a heat-resistant insulating material, and 2 a gas sensing element, which is installed in the center of the base 1. 3 and 3 are lead wires thereof, and 4 and 4 are connection pins connected thereto, and both support the sensing element 2 in its position. 5 is the coil heater, 6, 6 is the connection pin,
One end of each coil heater is extended and spot welded to the upper end of each coil heater, and the coil heater 5 is held concentrically with the sensing element 2. 9 is a net cover, and 10 is its mounting ring.

The coil heater 5 of the conventional example configured in this way is energized through the pins 6, 6 to heat it, and the sensing element 2 surrounded by the heater 5 is heated to a constant and uniform temperature (400°C). . When the gas sensing element 2 comes into contact with a flammable gas while in a high temperature state, its electrical resistance value decreases and the element 2 has the property of easily allowing current to flow therethrough. Therefore, a gas leak alarm is constructed by having the gas sensor configured as described above control the circuit of a sound generating device such as a buzzer.

However, the above-mentioned conventional configuration has some disadvantages. Although the heat radiated inward by the coil heater 5 is effectively used, the heat radiated outward, which corresponds to about half of the total amount of heat, is It is almost never used and is wasted. In addition, the conventional configuration has the disadvantage that the heater is easily subjected to the cooling effect of direct wind.

Furthermore, as shown in Japanese Utility Model Application Publication No. 57-16854, for example, by covering the gas sensing element with a skeleton-like heat insulating member, the gas sensing element can be heated by the heat generated from the gas sensing element. The gas that
There are some devices that prevent heat from dissipating to the outside from the space around the gas sensing element, and further prevent heat from dissipating to the outside by heat conduction using a covering member, but there are still methods to save power. It was inadequate in many aspects.

Purpose of the invention The present invention improves the conventional configuration that wastefully dissipates about half of the total amount of heat generated as described above, uses this as effectively as possible, prevents the cooling effect of wind, and achieves the following: The objective is to obtain a gas sensor with increased thermal efficiency and low power consumption.

Structure of the invention The present invention is one in which a heat reflecting plate is provided around the gas sensor.

DESCRIPTION OF THE EMBODIMENT FIGS. 2 and 3 show the structure of an embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same components.

Reference numeral 7 denotes a gutter-shaped reflector plate, whose inner and outer surfaces are nickel-plated, and the inner surface in particular is well polished to form a mirror surface with good reflection. Reference numeral 8 denotes a mounting piece, in which two reflecting plates 7 are mounted concentrically with the coil heater 5 on the upper surface of the base plate 1 with a slight gap between them.

In this embodiment configured as described above, the coil heater 5 is made to generate heat by being energized,
The heat radiated inward heats the linear sensing element 2, and the heat radiated outward from the coil heater 5 is also reflected by the reflecting plates 7, 7 and directed towards the sensing element 2, which heats the linear sensing element 2. to assist. Furthermore, since the sensing element 2 is placed in a high-temperature space surrounded by the reflectors 7, 7, air containing leaked gas enters the high-temperature space through the gap between the reflectors 7, 7, and the heater heats up. The convection generated by the air contacts the sensing element 2 closely, causing the sensing element to be sensitive to the gas in the air, and the reflecting plate prevents disturbances caused by wind and the sensing element from becoming obsolete. to prevent cooling.

Effects of the invention As described above, the present invention has the following excellent effects.

(a) A reflective plate with a well-polished inner surface is placed around the heater, so the heat from the coil heater is reflected well and is used for internal heating without escaping to the outside, making the sensing element more efficient. heated,
Therefore, the power consumption of the heater can be reduced.

Incidentally, the conventional one required 1.3W,
The device of the present invention required only 1.2W, which enabled a power saving of approximately 10%.

(b) Since there is a slight gap between the plurality of reflectors, the external air mixed with gas reaches the sensing element in a rectified state, and the sensing element is efficiently operated and free from external disturbances. You can feel without receiving.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional gas sensor, FIG. 2 is a sectional view of an embodiment of the present invention, and FIG. 3 is a perspective view of the sensor with its net cover removed. 1... Base board, 2... Sensing element, 3... Lead wire, 4... Connection pin, 5... Coil heater, 6...
...Connection pin, 7...Reflector, 8...Mounting piece, 9...
...Net cover, 10...Mounting ring.

Claims (1)

[Scope of utility model registration request] A semiconductor gas sensing element is arranged on the base plate, a coil heater for heating the gas sensing element is arranged around the outer periphery of the gas sensing element, and a coil A gas sensor that includes a plurality of heat reflecting plates with special reflective surfaces formed thereon so as to reflect the heat of the heater inward, spaced apart from each other.