Alfa Laval relief valves prevent vacuum or pressure build up inside tanks or vessels used in the brewery, food and beverage, personal care and biopharm industries.     To protect against overpressure and vacuum conditions while filling or emptying the tank of liquid, Alfa Laval two-way relief valves are mounted on top of an atmospheric tank in hygienic process lines.   The Alfa Laval range of relief valves (RV) consists of two models made of either polyethylene or AISI 304/316 stainless steel. The polyethylene model is designed for product flows up to 800 hl/h and is available in four different standard sizes : RV130, RV400, RV400A and RV800. The stainless steel model is designed for more stringent hygienic requirements. It handles product flows up to 1000 hl/h and is available in two different standard sizes: RV600 and RV1000.   The Alfa Laval tank equipment portfolio includes tank cleaning machines, agitators, rotary jet mixers, instrumentation, tank covers, sight glasses and other tank accessories.