Valves with screw shutter are devices that modulate the flow of fluid in a tube or in a liquid container. Different designs have been studied to meet all of the unit configurations and every situation in the field, considering the type of refrigerant fluid and the allowed pressures, as defined in the current standards. Castel has a wide range of valves with screw shutter that can be installed on a variety of commercial refrigeration systems and civil and industrial area air conditioning systems.