The Tuffy® II buoyancy level switches are float-actuated devices designed for horizontal mounting in a tank or vessel through threaded or flanged pipe connections. The compact size allows for installation in small vessels, while its many features provide a variety of application uses. The single switch mechanism is available in SPDT or DPDT forms on units designed for fixed or adjustable, narrow or wide differential and interface service levels.
All float operated liquid level controls operate on the basic buoyancy principle which states "the buoyancy force action on an object is equal to the mass of liquid displaced by the object." As a result, floats ride on the liquid surface partially submerged and move the same distance the liquid level moves. Because of this, they are normally used for narrow level differential applications such as high level alarm or low level alarm. Features
Single electric switch for high or low level alarm or control functions
Spacious switch wiring compartment
Pressure ratings to 2625 psig (181 bar)
Process temperatures to +750 °F (+400 °C)
NACE and/or ASME B31.3 construction
Specific gravity as low as 0.40
Options
Narrow or adjustable level differential
Silver or gold switch contacts
SPDT or DPDT dry contact or hermetically-sealed switches
External mounting chambers
Hastelloy C wetted parts
Operating principle
The TUFFY II achieves switching action through the use of repelling magnets on the float assembly and the switch mechanism. Separating the two magnets is a nonmagnetic pressure barrier.
The float follows the liquid level as it changes, causing the attached float magnet to move into the field of the switch magnet. The like poles of these magnets repel each other causing the switch magnet to change position, actuating the switch.
Approvals
ATEX
Ex d, Ex ia
CSA
XP
FM
XP
EAC (GOST)
Ex d, Ex ia
IEC
Ex d, Ex ia
NEPSI
Ex d
SIL
SIL 2 (1oo1)
TÜV/DIBt
WHG § 63, overfill prevention
Other approvals are available. Consult factory for more details.
