How To Detect Mass Flow in Existing Bins/Hoppers ?

(not verified)
Posted in: , on 20. May. 2003 - 00:53

Often times, it is necessary to verify during troubleshooting whether a certain bin/hopper/silo is operating in mass flow mode. Looking at the level of material from the top can be misleading because a tall funnel flow silo might also result in a flat draw down.

One of the methods to determine mass flow (i.e. material is moving along the hopper walls) is to insert rods or sticks & observe if they move due to solids motion.

Any other practical & bright alternate ideas ?


Detecting Nature Of Flow In Silo

Posted on 20. May. 2003 - 12:41

This is a useful suggestion Jack. For this reason, and also to inspect that residue is cleared from the transition region between the vertical body of the silo and the converging hopper section, it is useful to incorporate a small inspection port. This should be of minimum 100mm diameter, and located just above the transition ‘hip’ of the silo. A short ‘plug’ should be fitted to the removable flange, so that the inner face of the silo wall does not have a pocket to retain product.

Visual access potential at this point is also invaluable for the investigation of ‘quaking’ problems, should they arise. A guide to the fundamental causal mechanism is provided if it can be established whether the mass movement of material is continuous or intermittent at this point. The port could also be used to mount a level detection probe, if this is appropriate.

This point also emphasises the value of including sufficient inspection, access, instrumentation facilities and even retrofit potential at the design stage, rather than provided after fabrication. Considerable time and money can be saved when under the pressure of service or operating problems if facilities are in place to conduct a definitive investigation should problems arise in service. It is almost invariably a false economy to neglect these provisions.