SIKA flow switches from HMA Instrumentation are used to monitor volume flows. Depending on requirements, these are available for various nominal widths and set-point ranges. A modular approach allows product designs and options to be matched to a wide variety of applications. The broad temperature and pressure ranges, choice of materials and connection options ensure a very high level of versatility, which is why SIKA flow switches are used in applications such as heating, industrial cooling circuits, water treatment and potable water applications.

The flow switch consists of a paddle system with a permanent magnet attached to the end. Above this magnet is a reed contact, located outside the flow of fluid. A second magnet creates the force necessary to reset the switch back to the no flow position. When the flow being monitored pushes against the paddle system, the paddle swings away.

This changes the position of the magnet in relation to the reed contact, and thus activates the contact. As soon as the flow is interrupted, the paddle moves back to its starting position, thus activating the reed contact once again. The force necessary to push the magnet back is provided by the two magnets repelling each other. Using magnetic force instead of the usual leaf spring means that the switch is considerably more stable in the long term and much less sensitive to pressure peaks.