The below photograph shows two pressure switches sensing the same fluid pressure as an
electronic pressure transmitter:
glass bulb partially filled with mercury as the electrical switching element. When applied pressure
causes the bourdon tube to flex sufficiently, the glass bulb tilts far enough to cause the mercury
to fall against a pair of electrodes, thus completing an electrical circuit. A great many pressure
switches of this design were sold under the brand name of “Mercoid,” with a few appearing in this
photograph of a steam boiler (the round-shaped units with glass covers allowing inspection of the
bourdon tube and mercury tilt switch):
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.