When we say aseptic valves, that means the stainless steel is SS316L, and no dead corner of valve body inside.
The term aseptic means to be free from contamination caused by harmful bacteria, microorganisms, or viruses. When applied to valves, it means the materials and surface finish of the valve are optimized for exceptional cleanability. It also means each component of the valve that comes in contact with the process is hermetically sealed from the environment and atmosphere that surrounds the process. A PTFE diaphragm attached to the stem prevents harmful bacteria, et al, from getting into the process. Such as the sample valve below, when user gets liquid from a tank, he will use steam or fire sterilize to keep the hose barb ends aseptic.
Hygienic and aseptic valves have a lot in common. They share similar materials of construction and smooth surface finishes. Their design also requires there is no place for bacteria to hide within the valve. Despite their similarities, there are distinct differences between the two.
While aseptic valves aim to prevent contamination from the environment, hygienic valve design focuses on cleanability.
Parts of a hygienic valve will move in and out of the process, becoming exposed to the surrounding environment. For instance, a rising stem on a valve will come in contact with the process, and may also come in contact with the environment outside the process.
When do I use aseptic or hygienic valves?
Hygienic valves are common in food,beverage, and dairy manufacturing. They are found in processes where cleanability (CIP or COP) is extremely important.
Aseptic valves, are most often found in industries that require high levels of purity. These include manufacturers of injection drugs, cosmetics, microelectronics, and the like. Aseptic valves are used here to control processes and minimize contamination from environmental sources.