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Flow Switches

Rheotherm flow switches provide reliable switch protection in all types of liquid or gas service. From critical monitoring of extremely low flow process additives to loss of flow protection in large water or air lines, we can handle most flow switch applications. With no moving parts, long term reliability is assured. Options for hazardous locations (intrinsically safe/explosion-proof) are available.

What Kind of Service?
You name it – all types of liquids and gases, big pipes or small lines, hot or cold. Contact Us about any application you have. How Are They Installed?
Our in-line flow switches for monitoring flows in small lines are typically installed with standard tube fittings, but are optionally available with flanges, NPT, sanitary fittings, etc. Insertion probe flow switches for monitoring large (1" or larger) pipe flows are typically installed with 1" NPT or flange fittings. Can be used in vertical or horizontal lines. For most common applications, the sensor and electronics are an integral unit. How Do They Work?
Our in-line sensors use a straight-through flow tube with a heated and an unheated RTD attached to the outside of the tube. The insertion probe flow sensors have one tip with a heated RTD and a second tip with an unheated RTD. With either sensor style, the temperature differential between the two RTDs provides the primary flow signal: at high flow rates the differential is lower as flow removes more heat, and at low flow rates the differential is higher, as flow removes less heat. Nothing touches the fluid but the metal sensor wall, and there are no mechanical parts to wear, stick or break. Trip points are field adjustable. More on Method of Operation (PDF) What Models are available?

Model 100CS – Lowest cost industrial option. Integral sensor/electronics with one SPDT relay. Can be ordered with in-line or insertion probe sensor.

Model 100FS – Separate sensor and electronics with one SPDT relay. Option for second relay for high and low set points. Can be ordered with in-line or insertion probe sensor.

Model 400 – Integral insertion probe sensor and electronics; has nonlinear output signal option.

Model 500 – Flow switch for certain general purpose applications; 24 Vdc input power only.

How Do I Get One?