SDM ECO non-nuclear slurry density meter
Continuous, real-time slurry density measurement using ultrasonic acoustic impedance—without a radioactive source.
±0.5%
Typical accuracy
0–150°C
Sensor process range
IP68
Transmitter enclosure
2 × 4–20mA
Analogue outputs
RS485
Plus Ethernet and USB
No source
Non-nuclear principle
Why engineers specify the SDM ECO
The SDM ECO is designed for continuous density measurement in abrasive slurry duties where representative sampling is difficult and process changes need to be seen quickly.
Non-nuclear measurement
Ultrasonic measurement removes the radioactive source, licence and source-management burden associated with nuclear density gauges.
Continuous process visibility
See density movement in real time instead of waiting for intermittent laboratory samples or manual checks.
No moving parts
The acoustic measurement has no moving mechanical components in the measurement principle and no routine consumables.
Built for integration
Connect density to a control system through two 4–20mA outputs, Ethernet, USB or RS485.
How acoustic impedance measurement works
The SDM ECO sensor is mounted flush with the inside pipe wall. It sends an ultrasonic signal into the process and analyses the energy returned from the slurry boundary.
1
Transmit
The sensor introduces a controlled ultrasonic signal at the process boundary.
2
Interact
Part of the signal is reflected and part is absorbed by the slurry.
3
Calculate
The analyser evaluates the response against its configured calibration to determine density continuously.
Technical data
Core specification data from the Rhosonics SDM ECO product literature. Final suitability and materials of construction must be confirmed for the actual slurry and pipework.
| Measurement principle | Ultrasonic acoustic impedance |
|---|---|
| Typical accuracy | ±0.5% |
| Sensor process temperature | 0–150°C |
| Analogue outputs | Two 4–20mA outputs |
| Digital communications | Ethernet, USB and RS485 |
| Transmitter protection | IP68 / NEMA 6P |
| Optional display | 7-inch touchscreen, IP65 / NEMA 4 |
System components
Sensor
The wetted measurement component installed through the selected pipe integration.
The wetted measurement component installed through the selected pipe integration.
Transmitter
Processes the measurement and provides outputs to the plant control system.
Optional 7-inch HMI
Local touchscreen access for configuration and process indication.
Four manufacturer-defined installation options
Each system provides the manufacturer receiving flange for the SDM ECO sensor. The sensing face must finish flush with the inside pipe wall. On a horizontal pipe, Rhosonics recommends mounting around 45° from the bottom with the cable glands pointing downward. The final arrangement must follow the applicable Rhosonics installation manual.
Wafer
For larger-bore installations, the UWC wafer is shown with the genuine SDM ECO sensor fitted to the manufacturer integration. Rhosonics lists nominal pipe sizes from 4 to 60 inches.
Spool-piece
A complete factory-built spool with the SDM ECO sensor mounted through its dedicated receiving flange. Rhosonics lists nominal sizes from 1 to 20 inches.
Weld-o-let
The official Rhosonics drawing shows the weld-o-let receiving flange for steel pipe. It is listed for outside diameters above 3 inches and 5–22 mm wall thickness.
Clamp-in
The official Rhosonics drawing shows the clamp-in assembly fitted around the pipe. Rhosonics lists pipe outside diameters of 88–365 mm and 3–23 mm wall thickness.
Important: the drawings above are reproduced from the Rhosonics SDM ECO manual. They identify the genuine integration hardware; they are not AI-generated installation concepts.
Where real-time slurry density supports control
A useful measurement point is one where density can explain process performance or support a control action. PMA reviews the duty, pipework and validation method before recommending an installation.
Thickener underflow
Track underflow consistency before pumping, filtration or downstream solids handling.
Hydrocyclone feed
Use density alongside pressure and flow to understand classification conditions.
Grinding circuits
Monitor circulating load conditions and support stable mill operation.
Tailings transport
Follow slurry density through thickening, filtration and pipeline transport duties.
Field-proven installation context
The SDM ECO is applied in mining and mineral processing duties where abrasion, entrained air, deposition and changing solids all influence measurement quality. Installation geometry and calibration evidence matter as much as the instrument specification.
Engineering review checklist
A defensible recommendation starts with the process duty—not a product name. These are the inputs PMA uses to assess measurement feasibility and prepare the correct installation.
Slurry composition
Solids type, carrier liquid, expected concentration range, particle behaviour and likely entrained air.
Pipe and process
Pipe material, inside diameter, wall thickness, liner, pressure, temperature and flow regime.
Measurement objective
What decision or control action the density value must support, and the required update rate and accuracy.
Validation plan
Representative samples, laboratory method, commissioning checks and ongoing verification responsibilities.
Technical resources
Use the manufacturer literature for specification review, then ask PMA to check the application limits and installation details.
Find the right application guidance
Search PMA’s application library by process, material, measurement objective or location. Each result links to a dedicated engineering review page.
For dredger and pipeline duties, start with the dredging slurry density measurement guides. They explain density, concentration and production and link to application-specific review requirements.
Frequently asked questions
Key questions engineers ask when comparing non-nuclear ultrasonic density measurement with other approaches.
Is the SDM ECO a nuclear density gauge?
No. It uses an ultrasonic acoustic impedance measurement principle and does not contain a radioactive source.
Can it replace every nuclear gauge?
Not automatically. Suitability depends on slurry composition, entrained air, pipe geometry, temperature, pressure and the required validation method. PMA reviews these conditions before recommending replacement.
How is the sensor fitted to the pipe?
The sensor slides into the manufacturer receiving flange provided by the selected integration and is fastened using the prescribed mounting arrangement. The sensor face must be flush with the inner pipe wall.
How is the measurement commissioned?
Commissioning includes confirming installation, configuring the instrument, collecting representative reference samples and validating the calibration across the intended operating range.
Let’s talk about your application.
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