Models T20 & T21 Single-Stage and Dual-Stage Float Switches
Single Stage Switch
T20 units are simple, reliable float switches, designed for top mounting into tanks or vessels. T20 units utilize a single switch mechanism and float. It can be used for virtually any type of open or closed process or storage vessel, with either threaded or flanged type mounting, and actuating depths of up to 48 inches (1219 mm).
Dual Stage Switch
T21 units combine the functions of two separate narrow differential level controls in a single, compact, easy-to-install instrument. Two independent switch mechanisms are employed to provide two actuating levels at least 8” apart, at actuating depths of up to 48 inches (1219 mm), for applications such as high and low level alarm operation. Model T21 tandem float switches are available with optional cages to help stabilize the floats under turbulent conditions.
The buoyancy force of a process liquid on the float causes the float to move with the liquid surface. The movement of the float moves an attraction sleeve into the field of the switch magnet, pulling the magnet toward the sleeve and actuating the switch.
Fuel storage tanks
High and high/high alarm from single tank entry
Float diameters of 3" × 5", 4" and 4 1⁄2" available
Tank connections available in 1" NPT, cast iron, forged, or stainless steel flanges
Choice of switch mechanism:
Choice of switch enclosure:
NEMA 1 carbon steel for pneumatics
TYPE 4X/7/9 Class I, Div. 1, Groups C & D, polymer coated aluminum
TYPE 4X/7/9 Class I, Div. 1, Group B, polymer coated aluminum
ATEX approved housing
Float guide cage
Tropicalized switch mechanism
Special flange face finishes
XP=Explosion Proof (FM, CSA, ATEX)
ELV=EMC/Low Voltage (CE)
IS=Intrinsically Safe (ATEX)