Ameritrol - Model FD Series - Flow Switches Brochure

The FD flow switch features the same no moving part priciple of operation as is the lowest cost switch we offer. The low cost is achieved by limiting the process connection to 3/4″ MNPT and power input to 24 VDC. The sensor head is type 316L Stainless Steel and the output is an SPDT relay. The FD flow switch works using thermal dispersion technology where the temperature of a heated sensor is compared to the temperature of an unheated sensor. This temperature difference is greatest at no flow and decreases as flow rate increases. The unheated sensor acts as a reference such that the instrument only senses flow rate changes and is unaffected by process temperature changes.