Multi-port valve interfaces meet life science plant requirements

B. Braun's LIFE Nutrition plant, situated at the company headquarters in the North German city of Melsungen, is one of the world's most modern production sites for innovative nutrition. Products for clinical nutrition, such as amino acid solutions, carbohydrate solutions and fat emulsions are manufactured and packaged in two production lines at the new manufacturing facility, with its integrated laboratory. After more than five years of planning and construction, and an extensive test phase, the plant is scheduled to start full-time production during 2012.

The special challenges in the planning of LIFE Nutrition included the requirement that the new plant be housed in a building that is spatially identical to that of B. Braun's older LIFE plant. Despite this spatial constraint, the new production facilities needed to be significantly more efficient, flexible - and space saving. During the search for innovative, space-saving approaches for the complex valve interfaces required for production at the LIFE Nutrition plant, B. Braun's consulting engineer, Chemgineering, contacted a number of suppliers, fluid technology specialist Burkert among them. With its multi-port ROBOLUX valve, Burkert has a patented product in its portfolio for achieving very complex and compact valve interfaces with a low internal volume. Following consultations with Chemgineering on the process specifications, Burkert developed - within a few weeks - models for the first, very complex valve interfaces. These models were professionally visualised and presented with the help of modern 3-D PDF files.

Alexander Equit, National Key Account Manager for Pharma, Biotech and Fine Chemistry at Burkert, says: "The advantages of a Robolux multi-port system in comparison with conventional single-layer valve interfaces and ring systems were literally evident at first glance. The special feature of the patented Robolux valve design is that two independent process switching functions can be achieved with one membrane. This reduces installation requirements, eliminates T-adapters and minimises the overall number of valves and membranes required. The multi-port membrane valves were designed for high-purity installations and make it possible to design complex systems that are considerably more compact. Due to this technology, even a 10-port valve interface requires very little installation space, has a minimal internal volume and practically no dead flow zone. The lower inner volume offers several advantages: in addition to improved flow and evacuation properties, both cleaning and changeover of the interfaces for the manufacture of other products is easier and faster."

Valve interfaces that meet technical and practical needs

The valve interface concept presented jointly by Burkert and Chemgineering convinced B. Braun. On the basis of the Robolux valve interface, a new fluidics scheme was developed and modern multi-port Robolux systems were included in the provisional plans for the new LIFE plant. S. Reinhardt, a spokesman for C. Dostal, the organisation that operates both B.Braun's original LIFE Infusion and new LIFE Nutrition plants, comments: "The compact design, as well as the possibility to connect Robolux with standard systems, has resulted in valve interfaces that meet the technical and practical needs of the LIFE plant - such as maintenance and cleaning - as well as flexibility in different operational modes. These system solutions are unparalleled, prompting optimisations that standard solutions can only offer with difficulty, or to a limited extent."

The Robolux interfaces can be cleaned optimally and effectively due to directional flow. This systematically prevents the typical disadvantages of ring systems, which have especially large inner volumes and undefined flow, factors that complicate cleaning. The result of this design feature is that, in steam sterilisation, a Robolux valve interface reaches the required sterilisation temperature in about half the time. However, even with this, and the many other advantages provided by Robolux, the final decision to use the valve technology was still pending, because a number of hurdles still remained to be overcome. Alexander Equit explains: "The requirements and standards for use in Life Science systems are extremely high, not only at B. Braun, and are continuously reviewed through audits."

These requirements and standards impacted upon Burkert through a prerequisite to demonstrate that the complex Robolux valve interfaces could be delivered with a surface quality, as defined by the Basler Standard BN94. Here, an answer was provided by Burkert group company, BBS-Systems AG in Wil, Switzerland, which developed a system for reliable electro-polishing of the Robolux systems. This involves the removal of 30um of metal from the media contact surface with a special electrolyte, under the effect of DC current. The material is removed without mechanical, thermal and chemical influences. As a result, the surface becomes smooth and shiny in the micro range; possible damaged outer layers are removed, and the properties of the pure stainless steel can be utilised. For reliable electro-polishing of the complex interior of a 10-port system in all areas, the standard process had to be modified somewhat, and adapted to the special requirements of these systems.

Subsequent to the development of the electro-polishing system, audits were carried out to validate not only the electro-polishing process itself, but also the black-white separation in Burkert's production plants of products that are intended for the Biotech sector. This separation means that all components manufactured from stainless steel may come into contact only with stainless steel, to avoid contamination and rust film. This is also true for the bodies of fittings used in conjunction with the Robolux valves. These are produced on special production lines, where only stainless steel is used.

Quality and compliance to defined standards

Once the ability to deliver surface quality to the required standard had been demonstrated, the focus in the supply of the Robolux multi-port valve interfaces turned to actual production requirements: those of quality and compliance to defined standards, which are checked regularly in unannounced Factory Acceptance Tests (FAT).

As a key contributor to the FAT, Burkert conducted riboflavin tests on the most complex of the Robolux valve interfaces, using the company's own proprietary test rig. In compliance with the VDMA directive, the inside of the valve interfaces is fully soaked using an atomiser with a test solution containing riboflavin that fluoresces when exposed to UV light. With the help of these tests, the flow properties and cleanability of fluidic systems and valve interfaces can be determined with one hundred per cent reliability.

In addition to their primary objective, the riboflavin tests bring added benefits, in that the results of the tests can be used for optimising cleaning processes, in respect of cleaning cycles, cleaning time and the quantity of cleaning agents required. Moreover, the design of complex valve interfaces in a test phase can be evaluated and optimised by the use of riboflavin tests. This is a unique offering from Burkert, because the company is currently the only manufacturer of fittings and valve interfaces in the world that owns and operates a riboflavin test rig.

After the approvals process was completed, Burkert was awarded the contract not only for the Robolux valve interfaces, but also all the process fittings for the LIFE Nutrition plant. That was in 2009. Today, the project is in its final phase and Burkert is assisting with the commissioning of the valve interfaces and associated fittings, as well as conducting on-site training with the use of a show vehicle to familiarise operating personnel at the LIFE Nutrition plant with the new valve technology.

Summing up, Alexander Equit says: "This project was very challenging generally, but especially in terms of fluidics, since the entire plant operates only with pressure and gradients and without pumps. Nevertheless, with our Robolux valve technology, we have been able to provide a solution that satisfies the most demanding criteria in hygienic processing."

For further information abut the ROBOLUX range of multi-port process valves from Burkert, visit the website at www.burkert.co.uk.