Chinese
Spanish
Russian
Portuguese
French
German
Indonesian
Thai
Vietnamese
Arabic
Italian
Turkish
Polish
Japanese
Bulk solids radar level measurement tells an operator where a reflecting surface is within the instrument's view. That is useful for refill planning and process monitoring, but it is not a direct measurement of tonnes in a silo. The material profile, vessel geometry and bulk density determine whether a local distance can support a useful inventory estimate.
Decide whether the display means level, available space or stock
These quantities answer different questions. A high surface near an inlet may limit further filling even when other parts of the silo have space. Material left against the wall may produce a level indication although the outlet is no longer delivering. A procurement specification should say which decision the reading will support.
For replenishment planning, a consistent trend can be useful even where the absolute mass estimate is uncertain. For a commercial stock statement, the evidence must support the claimed quantity and uncertainty. Do not relabel a percentage level tag as percentage inventory without defining the conversion.
Show the viewing location on a silo section with its inlets and outlets. Record whether the surface at that location rises first during filling or falls first during discharge. This information is often more useful than a tighter catalogue distance specification when choosing where to install the radar.
Bulk solids radar level: four reasons the same distance can mean different stock
| Material condition | Effect on the stock interpretation |
|---|---|
| Filling pile | A measurement near the peak can overrepresent the average surface height. A different inlet may change the relationship without changing the instrument. |
| Discharge funnel | A low central surface can coexist with substantial material near the walls. A flat-surface tank table does not describe that profile. |
| Compaction | The surface can settle without the corresponding mass leaving the vessel. A changed bulk density alters a volume-to-mass conversion. |
| Retained material | Deposits, bridging or a persistent heel can remain visible but unavailable to the next process. Stored quantity and usable quantity may differ. |
Do not infer a bridge or rathole from one radar reading alone. Check discharge behaviour and other available process evidence through safe observation methods. A stable high indication with no material flow can have several causes, including a mechanical discharge problem or an incorrect echo.
Choose the antenna for the silo before choosing the stock calculation
The MV-RD903 uses a horn antenna for bulk solids. The MV-RD904 has a parabolic reflector, which needs a different clearance and access review. The MV-RD21S is an ambient-temperature solids configuration with a PE lens. Their assemblies should be compared against the actual nozzle, material and process conditions.
A narrower beam can help avoid a brace, yet it can also make the instrument more sensitive to which part of an uneven pile is observed. Neither a narrow beam nor a longer nominal range establishes whole-silo inventory accuracy. Check the viewing location through the expected profile changes rather than assuming the most focused antenna is always the most useful.
Include dust during loading and deposits after repeated operation in the enquiry. A photograph taken after the dust has settled does not describe the filling condition. Request application review for the actual material and avoid assuming that a model description for dusty service means immunity to every deposit or uninterrupted tracking in every process.
Check the conversion independently of the sensor
Keep three calculations identifiable: distance to a local level, surface interpretation to volume, and volume to mass. The first needs the correct reference. The second needs vessel geometry and an acceptable description of the material profile. The third needs a bulk-density value that is appropriate to the material state.
As an arithmetic illustration only, a calculated volume of 100 cubic metres gives 60 tonnes at an assumed bulk density of 600 kg per cubic metre, but 70 tonnes at 700 kg per cubic metre. These are hypothetical inputs, not measured values or an expected density range for a material. The example shows why improving radar distance resolution cannot correct an unsuitable density assumption.
Use an independent reference when assessing an inventory model. Depending on the site, that may involve verified weighing, a controlled material balance or an appropriate survey. Record the reference method's own limitations. A production balance with unrecorded transfers cannot establish radar inventory accuracy.
Compare more than one operating state. If the same indicated level corresponds to different reference quantities during filling and discharge, investigate the profile model rather than forcing one offset to fit both observations. Keep the raw distance available so a change in the calculation can be distinguished from a change in the instrument.
Make limitations visible to the person ordering material
Label a calculated stock value as an estimate where that is what the evidence supports. Show invalid or old readings clearly. A retained value after echo loss can look like stable inventory unless the receiving system carries the relevant status.
Recheck the conversion when the material, active inlet, discharge arrangement or density assumption changes. Do not carry a previous material's calibration into a new duty simply because the silo is unchanged. Use the silo commissioning procedure to plan observations during filling, storage and discharge before accepting the inventory calculation.
Questions about inventory readings
Q1. Can the radar replace silo weighing?
Only if its measurement and the proposed conversion meet the actual need. A level trend may be sufficient for replenishment planning, while a mass-based process may require weighing or a validated conversion. Compare the required result and its uncertainty rather than treating the instruments as equivalent.
Q2. Would a second radar make the stock estimate accurate?
Another viewing point can provide information about the profile, but it does not automatically define the whole surface or its density. Decide how the additional measurement will enter the calculation and validate that model. Two unexamined level readings are not a proven inventory system.
Q3. What should accompany an enquiry for a solids radar?
Provide the silo drawing, material, temperature, inlet and outlet locations, dust and deposit behaviour, and the intended use of the value. For a stock estimate, add the proposed density source and available independent reference. State whether the customer needs a local level, a refill trend or a defensible quantity estimate.
Summary
Select the viewing location and radar assembly for the material movement, then assess the inventory calculation separately. Send the silo layout and required output quantity to METRAVON application support. A clearly defined level trend is more useful than an unsupported precise-looking tonnage.
