How to Achieve Contained Gravity Transfer of Powders

Regardless of how well designed your powder handling equipment is, the interface remains the weakest point in the gravity transfer process. There are several methods to ensure the transfer is dust-tight, with the most popular being flexible sleeves and silicone dust caps. 

Flexible connections are a simple method of achieving contained transfer.

Dust caps offer an effective way of sealing an outlet tube to an inlet aperture for example IBC to IBC. Flexible sleeves have a similar application but tend to be more positive and require more assembly. Both systems provide a good dust tight solution and are ideal where height adjustment or some misalignment is required.

Silicone dust caps and sleeves are also a low cost and effective method of containing powders during process to process transfer. Another although less popular containment method used in gravity transfer is an inflatable seal. Inflatable seals do provide an effective sealing method but are high cost and prone to damage making regular replacement an issue. Early consideration of this vital element in the process should be made at the initial design stage of any successful powder handling system.

Although generally considered dust-tight and safe, for certain processes there may be concerns about the OEL (operator exposure levels) of flexible connectors. In these instances, it may be advisable to consider the use of a hygienic valve, to ensure measurable containment is maintained during gravity transfer.