Avoid Costly Bin Flow Problems

May/June 2021

Test Your Math Skills

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Joe and Rita are ant friends. They love to race each other but always tie, since they crawl at the exact same speed. One day, they designed a race that one of them could actually win.

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If they both take the shortest possible route to reach their crumb, who will reach their crumb first? (Don’t forget they’re ants, so of course they can climb anywhere on the edges or surface of the cuboid.) Think outside the box!

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QUOTE OF THE DAY

Pretty wild how we used to eat cake after someone had blown on it. Good times.

Avoid Costly Flow Problems

Economically Eliminate

Ratholing and Material Bridging

A solid understanding of a bulk solids flow pattern in a hopper is necessary to prevent system bottlenecks and process inefficiencies.

Cause and Effect

A few simple conditions cause most bin flow problems.

Hopper outlet is too small
Hopper depth is too great
Hopper slope is too flat

Two primary flow patterns occur in bins and silos.

Funnel Flow: A small active flow channel forms above the discharge outlet, but stagnant material, or "ratholes" remain at the periphery of the vessel. As the material level in the hopper decreases, the stagnant material may or may not slide into the flow channel, depending on its cohesiveness.
Mass Flow: The entire bed of solids is in motion when the material discharges from the outlet, eliminating the formation of stagnant regions in the vessel.

Ratholing occurs when material builds up on hopper or silo sidewalls. An active flow channel forms in the material above the outlet resulting in a slew of unwanted conditions:

Erratic flow
Reduced capacity of the hopper or silo
Worsening segregation
Increased particle degradation in stagnant areas
Eventual caking and spoilage

Bridging (or arching) occurs when discharged or fed material forms a bridge or arch over the outlet area in a silo or hopper. A "no-flow" condition results.

Economically Eliminate Hopper Flow Problems

Carman's Vibrating Bin Dischargers (VBD's) use vibratory action to promote bin flow and eliminate common flow problems, including ratholing and bridging.

How? Carman engineers carefully analyze the flow properties of your product or raw material in their laboratory or with rental equipment in your facility. Your individually engineered VBD will eliminate ratholing by increasing the effective hopper outlet size while the unit’s internal pressure cone eliminates bridging.

Expanded Flow

After the bin is initially filled (t=O), the Carman Vibrating Bin Discharger typically expands the channel of flowing product to its diameter. When the product in the center is sufficiently lowered, the product along the upper/outer walls sloughs off into the flowing channel of product and the cycle repeats (assumes that the bin is not simultaneously being refilled).

The Carman Vibrating Bin Discharger installs easily. Performance is guaranteed.

Read Carman's VBD literature here, contact your TEC representative or visit Carman Industries.