Cognesense - Measure, Monitor, Protect

764, 766, 768 (F)

For refinery and petrochemical operators, terminal automation teams, chemical and wastewater plant engineers, pump control system designers, and EPC firms who require two independent level switching points in a single external chamber, the Omnitrol 764 / 766 / 768 (F) provides a dual-actuator displacer switch designed for high-pressure service, clean alarm logic, and reliable pump start/stop control.

Unlike alternatives that require two vessel penetrations, complex wiring, or electronic tuning, the 76xF series combines:

Two mechanically independent setpoints
Factory-calibrated specific gravity settings
Adjustable switching gap
Hydrostatic proof testing at 1.5× design pressure
UL and CSA hazardous-area approvals

The result is a maintenance-friendly flanged chamber level switch that provides predictable HI / LO or pump control points in a compact and rugged design. It is ideal for pressurized and safety-critical applications across upstream, midstream, downstream, and industrial process facilities.

764, 766, 768 (F) Mounted Switches

Details

The Omnitrol 764 / 766 / 768 (F) Series offers dual-actuator mechanical displacer switching within a flanged chamber body, allowing two independent switching points without requiring two tank nozzles or complex piping arrangements.

This design is ideal in situations where:

Pump start and stop deadband must be factory-defined and adjustable
High and high-high alarms are required for API 2350 compliance
Space, vessel penetrations, or control system inputs are limited
Electronic sensors may drift or fail under heat, pressure, vibration, foam, or contamination

The chamber mounts externally to a pressurized vessel or bypass column, allowing the assembly to be isolated and serviced without breaking the vessel pressure seal.

Model selection depends on chamber size and switching gap requirements:

764F
766F
768F

Applications

Pump Short Cycling Protection: Dual switching points with an adjustable gap stabilize pump start and stop bands, increasing pump life and reducing nuisance trips.
HI / LO Protection with One Nozzle: Two independent actuators housed in a single chamber reduce vessel penetrations and installation costs.
Variable Product Specific Gravity: Factory calibration to the process specific gravity ensures accurate switching when product density varies due to temperature changes or blending.
Pressure Code Compliance: Pressure-class chamber options and 1.5× hydrostatic testing provide confidence for inspections and management-of-change reviews.

Technical Specifications

Parameter

Specification

Models

764F, 766F, 768F (dual actuator, flanged chamber)

Switching Points

Two independent trips; nominal 4″ spacing (adjustable approximately 2–6″)

Specific Gravity

Up to 1.4 SG, factory calibrated

Chamber Material

Carbon steel, 304 stainless steel, 316 stainless steel

Displacer Material

Graphite, 304 SS, 316 SS

Flange Class

ANSI 150 / 300 / 600

Temperature Capability

Dependent on material selection; suitable for hot service

Switch Output

SPDT or DPDT microswitch options

Enclosures

Weather-resistant, explosion-proof, rain-tight

Certifications

UL and CSA approved

Installation

Side-mounted flanged chamber

Typical Service

Pump control, HI / LO alarms, high-high safety trips

Variants

Also available in welded “W” body versions

2026 COST ESTIMATE

Support

If you have questions not covered here, please contact support for assistance.

When should I choose the 764 / 766 / 768 (F) instead of a single-point chamber switch?

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When you need two setpoints in one nozzle — for HI/LO alarms or pump start/stop.

What determines whether I choose the 764, 766, or 768 model?

The spacing and chamber size — select based on desired differential and vessel dynamics.

Does this device require field calibration?

No — it ships factory-calibrated to your specific gravity and switching differential.

Can it be installed in hazardous locations?

Yes — available with UL/CSA explosion-proof approval.

What if I need a welded chamber instead of a flanged chamber?

Specify 76xW for welded-chamber configurations; use 76xF for flanged.

Can I adjust the distance between the pump start and stop points?

Yes. The 764F/766F/768F features a configurable switching gap (approx. 2–6 inches), which is the difference between the high and low setpoints. This adjustability allows engineers to deliberately set a wider differential to prevent the pump from “short-cycling” during process surge conditions.

Is the switch reliable when the product specific gravity changes?

Yes. The unit is factory-calibrated to the specified SG of the fluid. While the switch will work across a range, the mechanical design ensures that the buoyant force needed for actuation remains consistent. By knowing the fluid’s SG, the factory ensures the physical switching points are accurate, eliminating a major source of error common in level switches.