These sanitary valves are quite popular with industries with extremely high sanitation requirements, such as food, beverage, pharmaceuticals, and so on.
This manual sampling valve is also normally closed. When the valve is opened, the valve stem and diaphragm seal unit are retracted, so that fluid can flow out. Flow speed can be controlled by rotating the handle.
The valve stem and diaphragm seal unit retract when the sampling valve is open, to let the material sample flow out. The PTFE diaphragm is optimal for high viscosity mediums.