The RHOTEC is a high-precision inline density and concentration sensor from Centec for continuous measurement in two-component liquid mixtures, based on the vibrating U-tube principle. It delivers exceptional accuracy (±0.0001 g/cm³, repeatability ±0.00001 g/cm³) across a wide operating range of −25 to +125 °C and up to 50 bar, covering applications from acids and alkalis to emulsions and solvents. Concentration is derived from a product-specific polynomial model, with automatic Pt1000 temperature compensation, full CIP compatibility, and an optional ATEX explosion-protection version.
The RHOTEC is a high-precision inline density and concentration sensor from Centec, designed for continuous measurement in two-component liquid mixtures across a wide range of industrial applications. Based on the vibrating U-tube principle, the product flows through a thin U-shaped measuring tube inside the sensor; electromagnets excite the tube at its resonant frequency, and an internal reference oscillator registers the oscillation pattern. Even minimal changes in liquid density alter the signal and are detected with very high precision — delivering accuracy of ±0.0001 g/cm³ and repeatability of ±0.00001 g/cm³. The relationship between density and concentration is described by a product-specific polynomial model, enabling the RHOTEC to display both density and concentration in various units. Temperature drift is automatically compensated by an integrated Pt1000 sensor. The wide operating range (up to 50 bar, −25 to +125 °C), broad material selection including Hastelloy and Tantalum, ATEX explosion-protection option, and full CIP compatibility make the RHOTEC suitable for demanding chemical, pharmaceutical, and food and beverage process environments.
Key Features RHOTEC
- Vibrating U-tube density measurement — exceptional accuracy ±0.0001 g/cm³ and repeatability ±0.00001 g/cm³.
- Density range 0–3 g/cm³; concentration derived via product-specific polynomial model; display in various units.
- Wide operating range: pressure up to 50 bar; temperature −25 to +125 °C.
- Suitable for acids, alkalis, emulsions, solvents; phase detection; crystallisation process monitoring.
- Automatic temperature compensation via integrated Pt1000 sensor.
- ATEX explosion protection option: Ex II 2G EEx d IIC T6.
- Wide material selection: 1.4404 / 1.4435 / AISI 316L, Hastelloy, Tantalum (others on request).
- Hygienic design; fully CIP-compatible. Process connection 3/8" thread; others on request.
- Transmitter version I/O: 6 digital inputs (24 V DC); 3 digital outputs (24 V DC); 2 analogue outputs (4–20 mA); Profibus DP optional. Sensor version (no display): Profibus DP standard.
- IP65; 24 V DC; compact patented design; optional local display. Patent EP 1 439 438 B1.
Applications
The RHOTEC is suited to continuous inline density and concentration monitoring in chemical manufacturing (acids, alkalis, solvents), pharmaceutical processing, food and beverage production, and any two-component liquid system requiring high-precision density-based concentration determination — including phase detection, crystallisation monitoring, and CIP concentration control.
Installation and Safety Notes
Install inline via 3/8" thread connection or alternative connections as specified. Power: 24 V DC. Fully CIP-compatible. Working pressure max. 50 bar; operating temperature −25 to +125 °C. ATEX option available for hazardous area installation. Select wetted materials appropriate for the specific process medium. Consult Centec for configuration and integration support.
Technical Specifications
| Measured parameters | Density; Concentration |
| Measurement principle | Vibrating U-tube density |
| Typical media | Acids; alkalis; emulsions; solvents |
| Typical applications | Phase detection; crystallisation monitoring; concentration control |
| Density range | 0–3 g/cm³ |
| Accuracy | ±0.0001 g/cm³ |
| Repeatability | ±0.00001 g/cm³ |
| Response time | ≤1 s |
| Working pressure | Max. 50 bar |
| Operating temperature | −25 °C to +125 °C |
| Temperature sensor | Pt1000 (automatic temperature compensation) |
| Wetted materials | 1.4404 / 1.4435 / AISI 316L; Hastelloy; Tantalum (others on request) |
| Process connection | 3/8" thread; others on request |
| Digital inputs (transmitter) | 6 × 24 V DC |
| Digital outputs (transmitter) | 3 × 24 V DC |
| Analogue outputs (transmitter) | 2 × 4–20 mA |
| Profibus DP | Optional (transmitter version); Standard (sensor without local display) |
| ATEX option | Ex II 2G EEx d IIC T6 |
| Protection rating | IP65 |
| Power supply | 24 V DC |
| CIP compatibility | Full CIP compatibility |
| Local display | Available depending on configuration |
| Patent | EP 1 439 438 B1 |
| Manufacturer | Centec GmbH |
| Brand | Centec |
