Chinese
Spanish
Russian
Portuguese
French
German
Indonesian
Thai
Vietnamese
Arabic
Italian
Turkish
Polish
Japanese
A silo can retain material near its walls while a discharge channel opens beneath the radar. Silo radar and ratholing must therefore be considered together when a low reading is used to declare the vessel empty. The instrument may correctly report its local target while the inferred total inventory is wrong.
Compare the beam location with the discharge pattern
Plot the radar axis, outlet and expected material movement on a silo section. Review operating evidence for funnel flow, retained wall material or a persistent channel. A sudden reduction in indicated level alongside limited discharged mass is a reason to investigate representativeness, not automatically to recalibrate distance.
Do not enter the silo or disturb retained material to obtain a reference. Ratholes and bridges can collapse without warning. Use the site's approved confined-space and bulk-solids procedures for any investigation, with safe external records where available.
| Evidence | What it can establish |
|---|---|
| Radar distance | The observed target along the selected path, subject to valid echo tracking. |
| Discharge record | Whether the apparent level change is consistent with known material removal. |
| Safe survey | Whether retained material or a channel makes one point unrepresentative. |
| Process history | Whether the behaviour depends on grade, moisture, storage time or discharge sequence. |
State the limitation of silo radar and ratholing in the specification
When locating an MV-RD21 bulk-solids radar, compare its nominal 3-degree beam path with the possible discharge channel. If that path follows a deep local depression, the resulting distance can be valid while stock remains elsewhere. Request the mounting assessment with the discharge pattern marked on the drawing; selecting a longer measuring range does not resolve this inventory limitation.
Define whether the required decision concerns local operating level, total inventory or material availability at the outlet. Those can disagree. A visible stock estimate does not establish that the product will flow, and a low local surface does not prove the walls are clear.
Choose additional evidence according to the decision
For stock reconciliation, compare the level result with accepted loading and discharge records or an independently assessed inventory method. Multiple level observations may help describe the surface, but they still require a conversion model and do not automatically produce accurate mass.
If material flow is the problem, changing the sensor alone does not correct hopper geometry or the material's flow behaviour. Have the responsible bulk-solids engineer assess that cause. Keep any revised aiming direction documented and test its consequences through both filling and discharge.
Q1. Can moving the beam to the wall solve ratholing?
It changes the sampled surface and may avoid the central channel, but does not remove the rathole or guarantee representative inventory. Assess the new location against the actual operating purpose.
Q2. Should the displayed low level be ignored?
No. Investigate what it represents and how the control system uses it. Do not suppress an alarm or substitute an assumed stock value without an authorised operating decision.
Summary
Separate local level from total contents and discharge availability. Provide the MV-RD21 beam location, outlet geometry and discharge observations before using one reading as an empty-silo decision.
