ELIMINATE RISK

Reliability of weir style valve diaphragms has been a hot topic for well over a decade.  In response, our industry has attempted to quantify expected lifespan of valve diaphragms based on the number of cycles (actuations, exposure to steam and CIP chemicals) in a standard biopharma process.

The reasons for this increased focus is that according to leading industry user groups soft part change-out programs accounts for over 50% of all planned maintenance activity.  Additionally, soft-part issues account for 20% of all equipment deviations and 10% or all corrective maintenance.  Most important, soft part issues represent the number on contamination risk in our industry.

From the user side, the industry describes excessive diaphragm replacement and the unpredictable nature of diaphragm life as major obstacles to production goals.  This is critically important because even a single failure during production can result in millions of dollars in lost production.

Although not part of the discussion of poor diaphragm performance, there is also the process design issue associated with weir style valves and the inability to eliminate dead-legs as well as reduce unnecessary piping.

A key to the well documented performance and reliability issues associated with weir style valves is compression set of the EPDM formulation for the main product facing diaphragms as well as the backing diaphragm for PTFE faced diaphragms. The reliability and type testing is focused on the performance of these EPDM elastomers with hot WFI viewed as the worst case scenario.

The Rattiinox CAD aseptic valve addresses these issues with a best in class precision machined PTFE diaphragm (PTFE USP Class VI-121°) with integral stainless steel pressure contrast armature.  The CAD valve diaphragm mounts to the manual or pneumatic actuator with a unique ball and cup system that allows the diaphragm to adjust to the valve body sealing point. Depending on the application CAD valves can be equipped with short or extended length diaphragms. The solid PTFE diaphragm allows the CAD valves to be used in a much higher temperature range than traditional weir diaphragm valves. The operating design temperature of the CAD valves is -80 to 200 °C (-112 to 392 °F).