A variety of technology solutions can measure level, volume and mass in single use systems utilizing disposable bioprocess bags. These include load cells, floor scales, pressure transmitters and guided wave radar.
In single use systems in bioprocessing, each technology poses its own set of benefits and limitations. For example, load cells, which determine weight, provide accurate, repeatable measurement but at a very high cost.
On the other hand, guided wave radar (GWR) level measurement is a far more cost effective control solution. However, potential difficulties arise when GWR is used in an environment using single use bioprocess bags. The nature of disposable, single use bags (in that they flex, fold and/or inconsistently form to the wall of a tote or bin) can negatively impact the repeatability of GWR level measurement.
Technical Article Demonstrates GWR Repeatability Optimization in Single Use Systems
A recently published article in Pharmaceutical Engineering, authored by David Ladoski, principal engineer at Amgen, and Dan Klees, hygienic business manager at Magnetrol®, investigates the use of GWR technology in a wide range of single use system environments. “Investigation of New Level Technologies in Single Use, Disposable Systems” compares variables including stainless steel bins, plastic/polymer and steel totes; solid rod and flexible cable probes; and inside wall and outside probe placement.
The article demonstrates that GWR technology, which typically costs one-third of the price of a load cell system, can deliver repeatability rates as low as 0.25% of total process liquid volume.
Additionally, the article discusses other benefits of GWR technology in single use systems, including the ability to perform periodic calibration verification on a bench dry calibration stand. For more information, we invite you to read the Pharmaceutical Engineering article, or contact Dan Klees at MAGNETROL.