Below is a list of Flow Switches manufacturers from St. Charles, Missouri. Flow switches are used to monitor fluid or gas flow while it is passing through its valve body, then to send an electrical control sign if the flow rate is too high or too low. The signal is sent as a safety measure to another device, such as a pump, that will respond accordingly or to a switching unit within the valve body. This is an important safety feature because many processes will only operate within a certain range of flow rate, halting or becoming compromised if the flow rate exceeds or falls under that range.