Flame-quenching keypad assembly

摘要

A process analytic device includes a metallic enclosure having electronics disposed therein. The enclosure has an enclosure wall with a reference surface. A plurality of operating rods is provided. Each operating rod is configured to pass through an aperture in the enclosure wall and to cooperate with the enclosure wall to provide a flame quenching pathway. A plurality of electrical switches is provided where each electrical switch is aligned with a respective operating rod, and is mounted a controlled distance from the reference surface. Each operating rod transfers movement to a respective electrical switch through the flame quenching pathway.

主权项

1. A process analytic device comprising:
a metallic enclosure having electronics disposed therein, the enclosure having an enclosure wall with a reference surface; a plurality of operating rods, each operating rod being configured to pass through a respective aperture in the enclosure wall and to cooperate with the enclosure wall to provide a flame quenching pathway; a plurality of electrical switches, each electrical switch being aligned with a respective operating rod, and being mounted a controlled distance from the reference surface, wherein the controlled distance is established by a plurality of shoulder screws; an elastomeric o-ring disposed about each shoulder screw to place a selected amount of tension on each shoulder screw; and wherein each operating rod transfers movement to a respective electrical switch through the flame quenching pathway.