Sanitary and aseptic process networks of all types rely heavily on the use of sanitary clamp connections in order to facilitate assembly, maintenance and in some cases, out of place cleaning. A reliable process depends upon the ferrules, gaskets and clamps working together seamlessly. These “make and break” connections contains four key elements.
The first three elements are obvious: Every sanitary clamp connection will include a pair of well-maintained ferrules that accept the gasket. The gasket is selected based upon the process conditions, with temperature being the primary limiting factor. Gaskets are also selected for their chemical compatibility to the product and any cleaning or sanitizing agents. The potential for extractables and leachables is also taken into consideration. Holding the ferrules together is the clamp. The clamp can either be a “low pressure” single wingnut or “high pressure” double bolt design. Clamps that are taken apart often should be inspected and replaced when wear to the bolt threads is evident.
Overlooked in many cases is the amount of clamp torque required for a safe and secure gasket seal. Look to our other discussion on elastomer performance. An all too common issue with sanitary clamp connections is the reliance on “hand tightening” of wing nuts. Since hand tightening is not reproducible from person to person, it creates significant variability in connection performance. When not sufficiently tightened, connections are prone to leaks that compromise the integrity of process systems.
Over-tightened clamps are just as problematic since they often lead to excess intrusion of the gasket into the process. The gaskets then serve as hundreds of entrapment points affecting everything from cleaning and drainability to product recovery. Furthermore, an intruded seal is significantly more susceptible to erosion which contaminates process streams. In highly regulated industries like Biopharmaceuticals, there just isn’t room for such variability and the myriad of resulting issues.
Once the proper torque is defined, the challenge is then how to properly apply that torque? Through the use of a calibrated torque tool fit with a specialized socket for use with clamp wing nuts, one variable can be removed from the process and replaced with a standardized method available to all operators.
The PharmAseptic torque tool solves the problems associated with improperly and inconsistently tightened sanitary clamps. The Universal Sanitary Clamp Torque Tools are available in several standard calibrated settings, 30 in/lbs, typical for silicone and some EPDM. Many customers have had success 40 in/lb for FKM gaskets and 50 in/lbs for PTFE. For our customers using the James Walker EP75B elastomer we recommend 44 in/lb. The slip style mechanism is generally preferred for the highest accuracy and repeatability.
The PharmAseptic Universal sanitary clamp torque tools provide a means of consistently tightening hygienic clamps thereby improving the reliability of the connection and reducing ergonomic issues. Since typical facilities can have hundreds if not thousands of clamp connections, the possibility of repetitive stress issues associated with hand tightening should not be overlooked.