Data Sheet
2100 and 2100E Level Switches
D200032X012
Product Bulletin
32.2:2100
February 2014
3
Specifications (continued)
Construction Materials (continued)
Flapper & Clamp Assembly (2100 only): Stainless
steel
Flapper Seat (2100 only): Fluorocarbon
Magnet (2100 only): Special material
Body Block: Steel
Cover:
2100: Clear plastic
2100E: Aluminum
Housing (2100E only): Aluminum
Other Metal Parts: Stainless steel
Options
2100 Switch Option: Individual street tee and bleed
orifice (when it is not desired to supply several level
switches from one common block and bleed
restriction)
Sight Window Option: A sight window is available for
either the 2100 or 2100E that installs in place of the
pipe plug, as illustrated in figure 1.
NACE Option: Constructions are available which
comply with the metallurgical requirements of NACE
MR0175‐2002. Environmental restriction may apply.
Shipping Weights
17.2 kg (38 pounds)
NOTE: Specialized instrument terms are defined in ANSI/ISA Standard 51.1 - Process Instrument Terminology.
1. Natural gas should contain no more than 20 ppm of H
2
S.
2. Normal m
3
/‐‐normal cubic meters per hour at 0_C, 1.01325 bar, absolute (Scfh‐‐standard cubic feet per hour at 60_F, 14.7 psia)
3. Pressure and temperature limits in this document and any applicable standards or code limitations should not be exceeded.
4. Water, Oil, Gas maximum working pressure. Corresponds to Cold Working Pressure: the maximum pressure rating allowed under normal ambient temperature conditions, which are usually
understood to be -29 to 38_C (-20 to 100_F). Refer to MSS SP‐25.
APPROXIMATE
SWITCHING POINT
LOCATION OF
OPTIONAL
SIGHT WINDOW
X0682
Figure 1. Fisher 2100E Electric Liquid Level Switch
Principle of Operation
Figure 2 shows the 2100 switch with the nozzle,
flapper, and magnet positioned for high level
activation. When the switch is in the normal position
with the flapper against the nozzle, output pressure
cannot bleed off and remains the same as full supply
pressure. Rising liquid level exerts a buoyant force on
the displacer, producing a torque on the torque tube.
When the torque transmitted by the torque tube
exceeds the torque exerted on the flapper by the
magnet, the flapper snaps away from the nozzle,
allowing output pressure to bleed through the nozzle
faster than supply pressure can enter through the
bleed orifice. The reduced pressure in the output
signal line activates the shutdown or alarm system.
When the liquid level lowers, the falling displacer
forces the flapper into the field of the magnet, letting
the magnet snap the flapper against the nozzle and
causing output pressure to build to full supply
pressure.