Non-Invasive Liquid Flow Measurement

German-based company, em-tec GmbH, has been developing and producing devices and components for the medical and bioprocessing industry for many years. The company has several years of experience and has become a strong partner in consulting, developing, and manufacturing non-invasive flow measurement systems using the ultrasound transit time principle. It has adapted the familiar and medically certified bidirectional Clamp-On flow measurement system for liquids for special requirements of the good manufacturing practice (GMP) – oriented bioprocessing industry.

The Flow Measurement System for Bioprocessing and Pharmaceutical Processes

The BioProTT™ flow measurement system comprises of a FlowTrack flowmeter with the measuring electronics as well as a disinfectable Clamp-On transducer. The clamp-on transducer can be easily affixed to the flexible tubing. Once the lid is closed, the measurement can begin without splicing the tubing lines. There is no contact between the sensor and the measured medium. As the sterility of the process is inherently guaranteed by the system design, it is ideally suited for processes with single-use applications and high hygiene requirements. This also protects users from being exposed to toxic or similarly hazardous substances while integrating flow measurement into a bioreactor set-up.

A broad range of flexible tubing (usually also meeting special requirements of the food and pharmaceutical industries) can be supported with sensor sizes ranging from 1/32" (0.8 mm, internal diameter) to 1" (25.4 mm) and flows ranging from a few mL/minute to 100 L/minute. The sensors can be calibrated for seven distinct parameters — with alternative tubing materials, different temperatures or media, for instance, depending on customers’ accuracy requirements. Media may be pure in the form of emulsion, or it may contain cellular components, proteins, salts, carbohydrates, or alcohols.

The system is available with various flow meter options with standard interfaces (4-20 mA/RS-232) such that an easy and optimal integration into the automated environment can be facilitated. The inclusion of a user interface and display allows the table version to be used as a stand-alone measuring device (as in laboratory setups).

System Accuracy

The system’s high accuracy has been demonstrated in various customer applications. With Clamp-On technology, the non-invasive transit-time ultrasonic flow measurement can achieve overall performance accuracy that is essential for typical process control applications. A comparison was drawn between the em-tec BioProTT™ flow measurement system and the three different single-use system setups (filtration system, isocratic chromatography system, and gradient chromatography system) as part of a poster presentation for an international event.

Flow rates from 2 to 16 L/minute were determined and assessed against a NIST-calibrated Coriolis meter. It was inferred from the results that flow rate measurement accuracies of better than ±2% of reading can be accomplished over the complete linear range with proper unit setup and material calibration.

Customized Solutions and Flexibility

One key advantage of em-tec GmbH is that it supports custom-made solutions and product developments with a very versatile and individual approach based on the following two features.

  • Customizable multichannel platform approach allows simultaneous monitoring of up to eight flow channels. A range of protocols and interfaces for individual process control integration can be provided and adapted to specific project requirements.
  • Flow measurement components are developed for incorporation into customer-specific projects (OEM integration) with flexibility to adapt to customer requirements, such as different housing materials for sensors (for example, for stainless steel instrument) or with varied branding options.

Process-Oriented Quality Assurance

em-tec GmbH’s quality management system is certified to ISO 13485. It offers an accurate and comprehensive technical documentation of a project and ensures that all stringent standards applied to medical device manufacturers are adhered to during a development process. Furthermore, em-tec GmbH has immense experience in all classes of medical FDA and CE approvals.

This information has been sourced, reviewed and adapted from materials provided by em-tec GmbH.

For more information on this source, please visit em-tec GmbH.


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