Liquiphant FTL50 – Detailed Overview
1. Working Principle (Vibronic / Tuning Fork)
- The FTL50 has a metal tuning fork that is continuously excited to vibrate at its natural resonance (~85 Hz).
- In air (or gas): the fork vibrates freely at a higher frequency.
- When liquid covers the fork: the vibration is damped → frequency decreases → electronics detect the shift.
- The switch changes state (relay or electronic output).
- This principle is independent of:
- Conductivity (works in non-conductive oils or conductive water)
- Dielectric constant (not affected by media change)
- Density (works down to ~0.5 g/cm³)
- Viscosity (works up to ~10,000 mm²/s)
2. Key Features
- Compact design → ideal for installation in tight spaces, pipes, and small tanks.
- No calibration required → plug-and-play solution.
- Failsafe mode selectable → High (overfill protection) / Low (pump dry-run protection).
- Self-monitoring electronics → diagnostic function with NAMUR NE 107 status signal.
- Wide media compatibility → from water to oils and aggressive chemicals.
- Maintenance-free (no moving parts, no wear).
- Safety rated → SIL2/3 certified according to IEC 61508.
3. Technical Specifications
- Measuring task: Point level detection in liquids
- Process temperature:
- Standard: –40 °C … +150 °C
- Special versions: up to 280 °C
- Process pressure: up to 40 bar (580 psi)
- Density limit: ≥0.5 g/cm³ (can be used with light hydrocarbons, solvents)
- Viscosity range: up to 10,000 mm²/s
- Pipe diameter: ≥25 mm
- Output options:
- Relay (SPDT)
- PNP/NPN transistor
- 2-wire AC/DC
- NAMUR signal
- Fieldbus (PROFIBUS PA, FOUNDATION Fieldbus)
- Ingress protection: IP66/67, NEMA 4X
- Explosion protection: ATEX, IECEx, FM, CSA, NEPSI (gas and dust applications)
4. Applications
- Overfill protection in tanks and vessels (safe shutdown).
- Dry-run protection for pumps (avoiding damage).
- Leak detection in pipelines and containment.
- Safety-critical loops (SIL-rated shutdown).
- Suitable for:
- Water & Wastewater
- Chemical and Petrochemical
- Oil & Gas
- Food & Beverage (hygienic versions available)
- Power Plants
5. Variants & Comparison
|
Model
|
Design
|
Application
|
Temp/Pressure
|
Notes
|
|
FTL50
|
Short fork, compact body
|
Tight spaces, small vessels, pipes
|
–40…150 °C, up to 40 bar
|
Standard model, general use
|
|
FTL51
|
Longer fork (extended insertion)
|
Large tanks, storage vessels
|
Up to 280 °C, 100 bar
|
For higher temp/pressure
|
|
FTL51C
|
Hygienic design (polished, EHEDG/3A)
|
Food & Beverage, Pharma
|
CIP/SIP cleaning, sterile
|
Stainless steel, hygienic
|
|
FTL62 / FTL64
|
Premium series
|
High-temp/high-pressure, safety-critical
|
Wider range, SIL 3 certified
|
Advanced diagnostics
|
6. Certifications & Standards
- Functional Safety: SIL2/3 (IEC 61508)
- Explosion Protection: ATEX, IECEx, FM, CSA, NEPSI
- Marine approvals: ABS, BV, DNV GL, LR (for shipbuilding)
- Hygienic standards (for FTL51C): EHEDG, 3A, FDA-compliant materials
- Process safety compliance: WHG (German Water Resources Act)
