Mechanical Seals Update: Pharmaceutical and Food Applications

Second only to electric motors, centrifugal pumps are the most common machine used in the chemical process industries (CPI). Pumps are serving in every conceivable fluid application. They move all manner of fluids from wastewater to paper pulp, from ultra-clean and purest pharmaceutical liquids to crude oils laden with a great variety of contaminants. Hundreds of millions of these pumps are fitted with mechanical seals at the point where shafts protrude through the pump casing. And some of these seals must satisfy very special requirements; the prevention of contamination is among them. Appropriately, process pumps in the pharmaceutical and food-and-beverage industries are subjected to stringent hygiene and cleaning requirements. These include clean-in-place (CIP), and steam-in-place (SIP). Industry and its regulatory agencies seek to reduce, and hopefully eliminate, the possibility of bacteria and micro-organism growth. Cleanliness is especially important on surfaces that are in contact with, or “wetted” by, the processed media. Needless to say, such contamination is detrimental to the finished processed product; therefore, considerable efforts are made by plant operators, engineers and managers to avoid contamination. But…