I.S. Flow Sensors
Inserted into Zone 1 and Zone 21

The following range of flow switches are designed for pipe insertion, threaded into a tee or pipe socket, with the probe inserted into the flow. Models available may be used to monitor air, gases or liquids. These switches operate on the calorimetric principle and monitor the velocity of the flow (not mass or volume). The switches are known for reliability of the set-point even during temperature variations, accurate and dependable switching, short reaction times and high pressure resistance. They are frequently used for flow/no flow, run-dry and leakage applications.
 

Where insertion flow sensors are used in hazardous areas, two zones may be involved. For example, in a Zone 1 (or Zone 21) area, an insertion sensor may be fitted to a water (or other non-hazardous media) pipe. In such a case, a sensor suitable for Zone 1 is appropriate as shown on this page.

These intrinsically safe flow sensors must be used in conjunction with a Flow Sensor Safety Barrier for Zone 1 Insertion. Setting adjustments are made using a potentiometer on the Safety Barrier for Zone 1 Insertion.

However, in a Zone 1 area, a sensor may need fitting to a process line, inside which a Zone 0 area exists. In this case, the sensor must be approved for use with the sensing element in Zone 0. See Flow Sensors Zone 0.

Outside Pipe = Zone 1

Inside Pipe = Zone 1

Flow Switch & Sensor in Zone 1
(not inserted into Zone 0)
[Atex Category II  2G  Ex  Zone 1]