Liquid level detection built on the oldest and most reliable principle in instrumentation.
A float level Switch uses buoyancy to track liquid surface movement, with a magnetic float rising and falling along a stem to actuate reed switches or drive a resistive element, producing either a discrete switching signal or a continuous 4-20 mA output for real-time level monitoring.
The float type level Switch range covers point-level and continuous variants in vertical stem, side-mounted, and cable-suspended configurations, with stainless steel, polypropylene, and PVDF wetted materials for outputs including 4-20 mA, relay, and Modbus RS485.
Dutco Tennant LLC is a premium supplier of instrumentation and process measurement solutions across the UAE and GCC, offering a broad portfolio matched to the region's oil and gas, water, chemical, and marine sectors.
Proven Level Detection Across the Most Common Process Conditions
- No electronics at the sensing point on reed switch variants — buoyancy and magnetic actuation alone trigger the output
- Hermetically sealed reed switches deliver over 10 million switching operations with no calibration required
- Normally open or normally closed output is field-selectable to suit pump control, high-level alarm, or low-level cut-off logic
- Wetted materials in SS316L, polypropylene, PVDF, and PTFE cover media from potable water and fuel to acids and solvents
- ATEX and IECEx certified variants support Zone 0 and Zone 1 hazardous area installation
Onboard Capabilities That Simplify Integration
- Continuous Analogue Output: The float liquid level transmitter converts float position to a linear 4-20 mA signal via magnetic coupling for direct input to PLCs, DCS, and SCADA systems
- Multi-Point Switching: Multiple reed switches along the stem provide stepped detection for pump sequencing and dual-level alarm logic from a single instrument
- Loop-Powered Transmitter: Integral signal conditioner variants eliminate the need for a separate field enclosure, reducing installation footprint
- Local Indication: Select models include an LCD or graduated scale on the stem for on-site level reading without auxiliary instruments
- Hazardous Area Outputs: Flameproof and intrinsically safe housings carry FM, ATEX, and IECEx documentation for classified locations
Types
Vertical Stem-Mounted Float Level Switches
Top-entry units mount through a flanged or threaded connection, with a doughnut-shaped float riding the stem to actuate one or more reed switches at set points.
- Customisable stem lengths for single or multi-point switching on closed tanks and pressurised vessels
- SS316L, polypropylene, and PVDF material options for broad media compatibility
- Suited to top-entry installations where side access is unavailable
Side-Mounted Float Level Switches
Horizontal units install through a single side-wall connection, with the float pivoting on a short arm to trigger the internal reed switch at the set level.
- Compact design for tanks where top-entry nozzles are restricted
- Reversing the mounting orientation switches between NO and NC output without rewiring
- Common in lube oil, bilge, and fuel storage tank applications
Cable Float Level Switches
A cable-suspended float tilts at the set level, rolling an internal ball to actuate a microswitch, suited to tanks with irregular geometry or inaccessible tops.
- Cable length customisable for deep sumps, wet wells, and open reservoirs
- Chemical-resistant housing for wastewater, sewage, and leachate service
- Low-cost, no-maintenance solution for simple pump start and stop duty
Continuous Float Level Transmitters
The float type level transmitter for continuous measurement uses a resistive stem and magnetic coupling to deliver a 4-20 mA output linear to liquid level across the full measuring range.
- Interface measurement possible with dual floats of differing specific gravity on a single stem
- Compatible with PLCs, panel meters, and HMIs without additional signal conditioning
- Local display options available alongside the analogue output
Magnetostrictive Float Level Transmitters
High-accuracy variants measure float position via torsion wave return time on a sensing wire, achieving resolution to 0.5 mm for custody transfer and critical inventory applications.
- Measuring ranges to 15 metres with HART and Modbus RS485 output
- Simultaneous level and interface measurement with two floats on one stem
- FM, ATEX, and IECEx approvals for refinery and chemical plant installations
Standout Features & Benefits
Mechanically Simple, Long Service Life
- Reed switch actuation requires no power at the sensing point and no periodic calibration
- Rated for over 10 million switching cycles across clean liquids without component wear
- Floats with specific gravity from 0.5 g/cc accommodate light hydrocarbons and low-density process media
Broad Media and Process Compatibility
- Wetted parts rated to 900 psig and 400°C on heavy-duty alloy configurations for high-pressure vessel service
- Fully non-metallic polypropylene and PVDF assemblies handle acids, alkalis, and aggressive solvents
- Hygienic stainless steel variants meet food, beverage, and pharmaceutical sanitary standards
Flexible Installation
- Top, side, and cable mount options address every tank geometry and process connection type
- NPT, BSP, and flanged connections suit standard vessel nozzles across international piping specifications
- Multi-point stem layouts reduce instrument count by covering high, low, and intermediate set points in one unit
Safety Certifications
- ATEX Ex d and Ex ia approvals for Zone 0 and Zone 1 explosive gas atmospheres
- FM Class I Division I ratings for North American project compliance
- SIL-capable models with IEC 61508 documentation for safety instrumented system applications
Application Areas
Water and Wastewater Treatment
- High and low level alarm switching on potable water tanks, clear wells, and ground-level reservoirs
- Pump start and stop control in lift stations, wet wells, and effluent transfer sumps
- Level detection in chemical dosing tanks for pH correction and disinfection systems
Oil, Gas and Fuel Storage
- Overfill protection and low-level pump cut-off on diesel, fuel oil, and crude oil storage tanks
- Lube oil and hydraulic reservoir level monitoring on rotating equipment packages
- Interface level detection between oil and water in separators using dual-float continuous transmitters
Chemical and Industrial Processing
- Level switching in acid, alkali, and solvent storage using PVDF or polypropylene-wetted assemblies
- Batch fill and drain control on reactors, blending vessels, and day tanks
- High-level alarm on secondary containment bunds and drip trays for overflow protection
Marine and Building Services
- Bilge and ballast tank monitoring on marine vessels using SS316L side-mounted switches
- Sump and drainage pit pump control in basements and plant rooms using cable float switches
- Cooling tower basin and boiler feed tank level control in commercial HVAC and utilities systems
