Tool calculates wetted surface area

Tool visibly demonstrates the importance of using fully traceable diaphragm material on hygienic applications.

Crane Process Flow Technologies has developed a tool that calculates the total wetted surface area for a mix of valves and weirs, and for a simple comparison illustrates the conclusion as a length of hose.

For example, a typical processing system incorporating 1000 sanitary and aseptic valves of varying sizes would contain a total diaphragm wetted surface area of around 10.25m2, which equates to a 161m of 20mm nominal bore hose.

Many biopharmaceutical processing plants use hundreds, even thousands of diaphragm valves.

The diaphragm itself is the key performance component within the valve, but it can be a potential source of process environment contamination.

So, considering the combined wetted surface area of these diaphragms, the issue of elastomer selection is seen in full perspective.

The tool visibly demonstrates the importance of using fully traceable diaphragm material on hygienic applications.

It also lets the user visualise the total diaphragm wetted area and understand the implications and associated risks of not using fully traceable components.

It is important that elastomers employed in aseptic applications conform to the FDA Code of Federal Regulations, Chapter One, Title 21, Part 177, para 2600 Rubber Articles Intended for Repeated Use and para 1550 Perfluorocarbon Resins, Issue Revised April 2002.

However, FDA conformance is just the starting point in ensuring the diaphragm supplied meets quality and performance characteristics.

CPFT elastomeric diaphragms used in the Saunders HC4 range are made from a formulation of raw materials that have been precisely weighed and combined into a compound by controlled intermixing.

The uncured or unvulcanised compound is then calendered into continuous 100m sheets, forming the basis of the diaphragm's internal structure.

Physical properties of the elastomer are determined during the latter stages of the blending process and a representative sample is subjected to a number of analyses, including rheometer (a measure of vulcanisation characteristics), tensile strength, hardness and elongation parameters.

Identification numbers are moulded onto the finished diaphragm which trace its manufacturing history back to the initial blend.

The historical information enables the product to be rigorously investigated right back to its source, a vital route in the event of a problem during use and acts as a guarantee that it conforms to the supplier's specification.

In addition, CPFT provides certification of the physical properties of each batch to ensure product consistency, supported by a complete documentation validation package for all diaphragms which make contact with bioprocess media.

Elastomers are a complex mix of ingredients and are selected to provide the desired properties for both the functions of the component and its intended application.

The ingredients will include a base polymer, activators, fillers and curing agents, and may be augmented with process aids and accelerators.

All can affect the properties of the elastomer.

Unfortunately, some users underestimate or even overlook the critical importance of elastomeric components and the consequences of these oversights may lead to contamination of the line media or even plant stoppages and their associated financial implications.

All Saunders diaphragms are developed and manufactured in-house, allowing CPFT to take complete control of technological advancement and design.

Saunders diaphragms have also been tested and certified in accordance with USP Class V and VI by an accredited independent test laboratory.

For many years, the bioprocessing industry has demanded that all stainless steel components are supplied with full traceability but then relegated polymers merely to complying with FDA Drop Register.

As valuable as FDA compliance is, it does not provide the customer with any physical characteristics or provide any indication of performance level within the process.

Thankfully now, however, there is a shift in focus towards fully traceable polymer components and the industry is beginning to demand real vigilance in this area.

In conclusion, the role of elastomers in bioprocessing systems tends to be underestimated but can be critical.

The technology is available to manufacture diaphragms to the traceability requirements of EN 10204.3 1b to complement the stainless steel content of processing systems.

In short, choosing a diaphragm made from an elastomer compound that complies with FDA and is certified to USP can mean ease of validation and confidence in product quality and purity.

Fully traceable diaphragm valve materials offer a guarantee that the product quality conforms to the customers' specifications and significantly reduces the risk of contamination from unknown materials entering the process.

Increasing demands of the pharmaceutical industry place traceability of materials as one of the most important factors to avoid contamination in sterile environments.

When choosing a diaphragm valve it is paramount that the same standards should apply.

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