| 摘要 |
A sensor assembly for a fluid flow meter, more particularly a gas meter, includes a sensor well made of a non-magnetic material and a sensor which is removable from the well without depressurizing the fluid line in which the flow meter is located. The sensor well is mounted within a bore formed in a meter body boss and, in a preferred embodiment, extends through the internal rotor housing and includes an inner face contoured to conform to the inner wall of the housing. In certain embodiments of the invention, the sensor is shaped to cover the sensor well mounting bolts so that the well cannot be removed without first removing the sensor. In other embodiments, the sensor well mounting bolts are retained in the sensor well by dowel pins, stakes or retaining rings such that the bolts must be gradually and sequentially loosened to remove the sensor well, in order to prevent improper removal of the sensor well from the meter body boss. In still other embodiments, the sensor well is threaded directly into the body boss or includes a threaded collar and a sleeve which is rotatable to facilitate positioning of a contoured face relative to the housing inner wall. In such embodiments the body boss includes an annular recess which allows pressurized fluid to escape from between the sensor well and body boss as the sensor well is removed, thereby providing an audible warning that the line on which the meter is mounted is pressurized.
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