AODD Pumps Conquer Challenges of Latex Emulsion-Handling

Contributed by: Xavier Rasotto at Wilden Pump

By their very nature, emulsions are difficult to blend and transport, requiring high levels of precision in the manufacturing and handling processes, and latex emulsions present many of those same handling challenges.

Despite their versatility in usage and popularity for enhancing products’ durability, dimensional stability, and chemical resistance, latex emulsions present two basic challenges that make them incompatible with most pump types. First, they are extremely shear sensitive, and thus require a pump that can reliably deliver a low shear rate. Second, they require a seal-less pump to prevent any air contact, which would further polymerize the latex.

Other pump features that would ensure proper handling include: dry-run capabilities, ability to handle liquids with varying viscosities, self-priming operation, portability, and ease of maintenance. Latex emulsions must also be stored at temperatures between 40 degrees F and 100 degrees F to prevent repeated freezing/thawing or surface drying, which can occur at either temperature extremes. Failure to store latex emulsions at the proper temperature can result in compromised performance.

Nearly every pump type has been unable to provide total coverage for every concern associated with transporting latex emulsions. Gear pumps, centrifugal pumps, progressive cavity pumps, screw pumps, circumferential piston pumps, peristaltic (hose) pumps have all been offered as solutions to this challenge, yet all have operational gaps that prevent them from being the ideal pump type of transport latex emulsions. Gear pumps, for example, are not recommended for shear-sensitive fluids; centrifugal pumps may require priming. The complete package does not exist within this range of pump types.

Where the aforementioned pumps fail, however, air operated double diaphragm (AODD) pumps do not. Although latex emulsions can be challenging to transport, AODD pumps offer a comprehensive solution that addresses the most prominent handling concerns or shear-sensitivity and product containment.

Jim Wilden, founder of Wilden Pump & Engineering Company, invented AODD pumps in 1955; more than half a century later, they remain a top choice for latex-handling applications. These positive-displacement-style pumps offer the seal-less, bolted configurations and high levels of shear-sensitive operation necessary for successful latex emulsion handling. The positive-displacement-style also ensures a consistent product flow rate. Aluminum or 316 stainless steel are preferred materials of construction for AODD pumps handling latexes and can be designed and manufactured in a variety of sizes.

View the complete article and more information on Wilden Pumps.

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