External cage type level switches

External cage type level switches are completely selfcontained units designed for side mounting to a tank or vessel with threaded or flanged pipe connections. In hundreds of industrial applications throughout the petroleum refining, petrochemical production and power generation markets, these switches have thoroughly demonstrated their worth for years.


Technology of External cage type level switches

A permanent magnet➀ is attached to a pivoted switch actuator and adjustment screw ➁. As the float ➂ rises following the liquid level, it raises the attraction sleeve ➃ into the field of the magnet, which then snaps against the non-magnetic enclosing tube ➄, actuating the switch ≈. The enclosing tube provides a static pressure boundary between the switch mechanism and the process. On a falling level, an Inconel ® spring retracts the magnet, deactivating the switch.

External cage type level switches 2

Features of External cage type level switches

  • Carbon steel float chamber.
  • Easy inspection of float chamber through removable head.
  • Stainless steel float and trim.
  • Service pressures up to 900 psig (62 bar).
  • Process temperatures up to +1000 °F (+538 °C).
  • Specific gravity ratings as low as 0.40.
  • Available switch styles including dry contact,hermetically sealed and pneumatic.
  • Single or multiple switch mechanisms available.
  • Available switch enclosures include : NEMA 1 carbon steel for pneumatics,TYPE 4X/7/9 Class I, Div. 1 Groups C & D aluminum
    TYPE 4X/7/9, Class I, Div. 1, Group B, aluminum 1″, 11⁄2″, or 2″ tank connections available in either NPT, socket weld, flanged side/side or flanged side/bottom construction.
  • Optional high temperature insulation available.

Applications of External cage type level switches

  • Accumulators
  • Flash tanks
  • Receivers
  •  Knockout drums
  •  Flare pots
  •  Storage tanks
  • Scrubbers
  •  Separators