The Kobold KAL-D compact thermal flow switch combines the features of Kobold's KAL-K thermal flow switch with a compact size. It uses the calorimetric principle to monitor the flowrate of non-viscous water-based liquids. The sensor tip is heated to a few degrees above the liquid temperature. As the liquid flows across the tip, it is cooled by the liquid. The amount of cooling is proportional to liquid velocity. The liquid velocity is compared to the setpoint which is field-adjustable by the user. A transistor switch is activated when the flow setpoint is reached.

The smooth measuring probe has no moving parts making it exceptionally reliable and insensitive to dirt and solids. The insertion type probe allows for flow monitoring with minimal system pressure loss. It achieves superior compensation for changes in liquid temperature during the measuring cycle by use of a microcontroller. This method of temperature compensation allows for very precise correction of flow measurement when liquid temperature changes occur. Specifications: switching range 0.15-6.6 ft/s, max pressure 580 psig, max operating temp 176°F (CIP 250°F), repeatability ±2%.