Pneumatic Conveying in Pharmaceutical Production

A pressure conveying line releases product wherever it leaks, and for a potent compound that is unacceptable along the whole length of the route. A vacuum line fails the other way: a leak admits air, the product stays inside, and the containment is intrinsic rather than maintained.

That shifts the problem to the ends. The vacuum receiver has a filter that has to be cleaned of product, and a discharge valve that opens into the next vessel. Those two components are where an operator can meet the compound, and they are where the containment design belongs.

Filter cleaning is the specific issue. A reverse pulse or a mechanical shaker releases the collected product back into the receiver, and the mechanism, its seals and its air supply are all inside the containment boundary. A filter changed by hand on a potent compound is an exposure event unless it was designed not to be.

And everything has to be cleanable and qualified. The advantage of a vacuum line is that its product contact surface is a smooth tube; that advantage is lost if the receiver internals cannot be reached.

In pharmaceutical production the direction of a leak decides the concept, and no other industry asks that question first.

Transfer by vacuum wherever the compound is potent, so the line itself is intrinsically contained and the design attention goes where the exposure actually is.

A receiver whose filter cleaning mechanism and discharge valve are specified as containment components, with stated performance and a cleaning route that reaches everything.

A documented package: materials, surface finish, containment figures, cleaning method and swab points, under change control.

In a building materials plant the same route is decided by abrasiveness over distance, and dilute phase chosen for a long cement line wears its bends out first.

The route is designed as vacuum from the start. A receiver above the destination vessel, a smooth tube from the source, and a discharge valve that opens into a closed connection. The product contact surface is then a tube and a vessel, which is as little as a transfer can be.

The filter is then the design focus. A filter element that can be cleaned in place by a mechanism whose seals are part of the containment, with a defined procedure for element replacement that does not expose the technician. Where the compound is potent enough, element changes happen inside a containment enclosure.

The discharge valve is treated the same way: for a potent compound a split butterfly arrangement keeps the contaminated faces together, and its containment performance is a measured figure for that size.

Cleaning is designed next, in place or out of place, with spray coverage or a dismantling route, and swab points defined. And the vacuum source itself is specified with its exhaust filtration, since that is the one place air leaves the system.

• Vacuum rather than pressure wherever the compound is potent, for intrinsic containment.
• Receiver filter cleaning mechanism specified as a containment component.
• Element replacement procedure designed not to expose the technician.
• Discharge valve with measured containment performance for the installed size.
• Cleaning route defined, in place or out of place, with swab points.
• Vacuum source exhaust filtration specified, since that is where air leaves the system.

• Containment band of the compound, which is the reason vacuum is chosen.
• Receiver filter cleaning method and whether element changes can be contained.
• Discharge valve type and its measured containment performance.
• Cleaning strategy, in place or out of place, including whether every surface is reachable.
• Product fragility, since vacuum transfer still has a velocity.
• Exhaust filtration on the vacuum source.