The location of a safety screen within a system is a very important design consideration. The safety screen should be located as close as possible to the critical component it is to protect. This will allow all of the flow entering this component, and only that flow, to be filtered by the safety screen. Safety screens are limited in their filtering capacity and therefore, every effort must be made by the designer to ensure that only the flow entering the critical component will pass through the safety screen. If the flow through a critical component is bidirectional then a safety screen should be located at each inlet. This design practice is followed with all Lee restrictors and valves where safety screen protection is required.