| 摘要 |
PURPOSE:To obtain a safety dry type gas meter without a solenoid valve by airtightly isolating an elecromagnetic coil operating a detaining mechanism to check rotational motion obtained by converting the reciprocating motion of a measuring film. CONSTITUTION:At a normal time, a permanent magnet 23 fitted to the other end of a detaining piece 22 is attracted by a fixed iron core 25 of an electromagnetic device, so that the rotational motion of a crank board 17 based upon the reciprocating motion of a measuring film 11 is carried out without troubles because a pawl part 22' is located under the crank board 17 and gas is sent from a gas meter while being measured. If current having a polarity checking the attracting power of the permanent magnet 23 is supplied to an electromagnetic coil 26 even in a moment, a pawl part 22' projected up to the rotational height of the crank board 17 and abutted to an engaging part 17', so that rotation is stopped and the reciprocating motion of the measuring film 11 is also stopped to interrupt gas feeding. Since the electromagnetic coil 26 is isolated on the atmospheric side by sealing a fixed iron core 25 penetrated into the wall surface of a mechanical room 30 by an O-ring, the whole gas meter system is safely prevented from flashed explosion. |
