Routing Powder to Multiple Destinations in Food & Beverage

A single mill, sifter or bulk bag station usually feeds several destinations: two or three silos, a line of day bins, a set of packers. One line and a junction is cheaper than parallel lines, and the junction is where the trouble concentrates.

The first problem is retention. Every diverter has a body volume, and the branch that is not in use is a dead leg holding powder from the last run. In a plant where the next product is declared free of something, that dead leg is where the declaration fails, and the cleaning procedure usually names the vessels and the line without ever naming the junction.

The second problem is the product itself. Flakes, coated granules and dried fruit pieces are damaged at an abrupt change of direction, and a junction with a sharp step produces fines that arrive at the packer as dust.

The third is simply being right. A misrouted batch sends one blend into the wrong silo, and at silo scale that is a disposal decision rather than a correction.

A junction whose entire product contact volume can be reached, cleaned and inspected within the changeover time the plant has, with no branch that is cleaned only by assumption.

A flow path with no step and no sharp transition, so a fragile product passes the junction without being degraded.

Routing that is confirmed rather than commanded: the system knows where the diverter actually is before material moves.

In a grain and feed plant traceability decides instead: the outlet position has to be read back from the valve, because a position taken from the command sends a load to the wrong bin.

The junction type is chosen for cleanability first. Flex tube diverters are common in food because a single flexible tube is the only product contact part; it swings between outlets, it can be removed by hand, and it can be replaced rather than cleaned when a changeover is tight. Plug and flap types hold pressure better and give a firmer seal, at the cost of a body that has to be opened to be cleaned.

Then the sequence is designed. Switching a diverter while material is flowing shears product, jams the mechanism and leaves a layer at the seal face, so the order is stop the flow, switch, confirm the position, restart. Confirming means a sensor on each end position, interlocked with the blower or the feeder, not an acknowledgement from the actuator that it was told to move.

The flow path is then checked for geometry. Radius rather than angle, no step at the junction face, and the same bore throughout: a junction that necks down is both a damage point and a place for material to sit.

Finally the junction is entered into the allergen matrix as its own item, with a cleaning method and a verification step, so it is cleaned at the frequency the matrix requires rather than when somebody remembers it exists.

• Cleanability of the whole product contact volume established before the type is chosen.
• Flex tube where changeover is frequent, plug or flap where pressure sealing dominates.
• Switching only at rest, with position confirmed by sensors on both ends.
• Interlock between position confirmation and the conveying air or feeder.
• Junction geometry free of steps and necks, with radii for fragile products.
• Diverter listed in the allergen matrix with its own cleaning and verification method.

• Allergen matrix and the changeover standard, which decide whether the junction is cleaned, dedicated or fitted with a replaceable element.
• Product fragility and the damage that is acceptable at a change of direction.
• Cleaning method, dry or wet, and the drying that has to follow a wet clean.
• Operating pressure, since a dense phase line needs a sealing capability a flex tube may not have.
• Number of destinations and whether one multi port device or cascaded two way diverters is the better risk.
• Dust explosion characteristics of the powder, which decide the sealing and any isolation duty.