Hochiki Corporation

Hiroshi Yashima

Yoshinori Kaminaka

Tetsuya Nagashima

Yoshihito Hirai

Tetsuji Sato

Satoru Koizumi

An ionization smoke detector of the present invention has an annular engaging flange portion formed integrally on the periphery of an insulating board and an engaging groove formed on a cover, so that a circuitry-accommodating portion may be moisture- and gas-tightly sealed merely by inserting the flange portion into the groove, without using special sealing members such as ruber packing members. In an intermediate electrode mounting structure of the present invention, support legs are formed integrally on the periphery of the intermediate electrode which may be simply inserted into an opening of the insulating board to fix and support the intermediate electrode, without using screws etc. Thus, a space needed to mount the intermediate electrode can be minimized. An electrode lead is connected to a lead of an FET insulatedly potted at an appropriate place on the backside of the insulating board with a hot melt synthetic resin. This can prevent possible penetration of moisture or corrosive gases into the circuitry-accommodating portion by the insulation sealing of the FET, even though the electrode lead passes through an opening of the insulating board. Thus, corrosion of the circuit parts can surely be avoided.

Moisture-proof ionization smoke detector

An ionization smoke detector of the present invention comprises an outer electrode having a plurality of smoke inlets formed on a side wall thereof, an outer cover and a partition wall having a plurality of smoke inlets disposed between the outer electrode and the outer cover to form a triple wall structure. The smoke inlets formed on the outer cover, the partition wall and the outer electrode are staggered from each other. Air stream hitting against the detector is attenuated by the triple wall structure and generally half of the air flow is allowed to pass between the outer cover and the outer electrode and between the partition wall and the outer electrode, flowing out of the detector and the remaining half of the air flow is led into the detector through the smoke inlets.

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Shibata, Japan

Hiroshi Yashima