For refinery engineers, chemical plant operators, power generation teams, boiler/steam system designers, and EPC specifiers who need high-pressure, high-temperature point-level protection with mechanical certainty, the Omnitrol 666/668(C) delivers compact, chamber-mounted displacer switching engineered for extreme duty environments.
Unlike electronic switches that drift or fail under heat, vibration, and pressure cycling, the Omnitrol 666/668(C) uses proven mechanical displacer technology, welded “C”-style chambers, and field-proven magnetic snap-action switching to ensure fail-safe level protection on liquids — including low-specific-gravity hydrocarbons, solvents, and steam condensate.
Ideal where space is tight, reliability is critical, and electronics are not preferred, this model is the go-to field-proven solution for pressurized vessels, blow-down drums, steam systems, condensate pots, and hazardous media tanks.
Engineered for tight piping layouts, high-pressure applications, and low-SG fluids.
Immune to drift, EMI, and thermal cycling; ideal as a mechanical safety layer.
Suitable for refineries, chemical plants, and classified hazardous zones.
Crisp switching with no chatter — even in turbulent or pulsing service.
No tank penetration; safe isolation from the process fluid.
Reliable actuation where floats and ultrasonic devices fail.
Ensures trip at setpoint for pump protection, shutdown, and alarms.
Compatible with aggressive chemicals and high-temperature media.
The Omnitrol 666/668(C) provides single-point actuation in a short welded chamber, offering minimal footprint and maximum reliability in demanding industrial environments. The displacer senses liquid buoyancy changes via Archimedes’ principle, triggering a magnetically-coupled snap switch that remains unaffected by foam, turbulence, vapor layers, or dielectric changes.
With no calibration required, no electronic failure modes, and fully external installation, this unit delivers dependable level protection for high-pressure vessels, low-SG fuels, steam loops, chemical service, and critical trip applications.
Designed as the compact alternative to “W” and “F” chamber versions, the 666/668(C) is ideal for single-point alarms in tight piping or skid-mounted systems.
| Parameter | Specification |
|---|---|
|
Technology |
Displacer-actuated mechanical level switch |
|
Chamber Type |
Short welded “C”-style external chamber |
|
Models |
666(C), 668(C) |
|
Actuation |
Single alarm/trip point |
|
Displacer Options |
Graphite (standard) or stainless steel |
|
Mounting Connections |
Side/bottom process connections (1″ NPT std; flange options) |
|
Housing Options |
Weatherproof, Explosion-proof, Vapor-proof, Rain Tight |
|
Ratings |
Class I Div 1 Groups B,C,D; Class II E,F,G options |
|
Temperature / Pressure |
Built for high-pressure/high-temp service (per specific model rating) |
|
Switch Output |
Mechanical snap-action microswitch |
|
Power Requirement |
None — mechanical operation |
|
Applications |
High/low level trip, pump protection, boiler cutoff, shutdown interlock |
Have a look at the flyer to get all the tech specs and product features.
Brochure
Read the manual for detailed information and instructions.
Manual
Check out a sample cert from our calibration lab.
Certificate
If you have a question that we have not covered then just get in touch and we’ll be happy to help.
We have tried to answer the most common questions we are asked here.
Mechanical displacer switches offer fail-safe action, no drift, and immunity to heat and EMI — ideal for safety and steam service.
Hydrocarbons, condensate, light solvents, process water, and most refinery/chemical liquids — including low-specific-gravity fluids.
No — the 666/668(C) is a single-point switch.
Yes — all mechanical components are external, enabling safe isolation and maintenance.
Yes — its pressure-rated chamber and mechanical design make it ideal for steam drums, blow-down systems, and condensate vessels.
The displacer system is engineered to sense very small density changes, outperforming floats and ultrasonic devices in LPG/NGL and solvent service.