Gas suction pump device, gas feed adapter and gas alarm unit

A gas alarm unit comprising:

• a gas suction pump device, suitable for use in being connected by a connecting tube to a portable gas alarm device, which comprises:
• a casing having a substantially rectangular framelike sectional shape having two side walls opposite to each other, and upper and lower walls which connect the side walls to each other, and formed slenderly in a gas flowing direction and into a size holdable by grasping with a hand;
• a control circuit board provided in the casing so as to extend in a longitudinal direction along the upper wall;
• a pump unit arranged in a region on the side of one side wall under the control circuit board, in which one end and the other end of a gas flow path defined by the pump unit and extending in the longitudinal direction of the casing communicate with a gas inlet port opened forward of the casing and a gas outlet port opened backward of the casing, respectively;
• and a battery fitting chamber provided in a region on the side of the other side wall,
• a connecting tube connected to the gas suction pump device at an end thereof;
• and
• a portable gas alarm device connected to the other end of the connecting tube through a gas feed adapter for connecting the gas suction pump device through a connecting tube to a portable gas alarm device equipped with a plurality of gas sensors which detect gases of different kinds from one another,
• said gas feed adapter including:
• a casing having an engaging part and detachably engaged with a gas alarm device body, wherein a gas feed port common to the respective gas sensors in the gas alarm device body is defined in one outer end wall of the casing, a connecting terminal to which the connecting tube is connected is also fitted so as to project outward, and a gas outlet for opening the internal space in the casing to the air is defined in the other outer end wall, and wherein:
• a main gas inlet passage extending in a zigzag manner from the gas feed port to the gas outlet is formed in the casing, and a plurality of branched gas inlet passages independent of one another for introducing air in the objective space to perform the measurement of gases into the respective gas sensors in the gas alarm device body are formed in the main gas inlet passage,
• and wherein air in the objective space to perform the measurement of gases is introduced from the gas suction pump device into the portable gas alarm device.