FISCHER Mess- und Regeltechnik GmbH
Product and functional description | 2
BA_EN_NK10_H_ST4-C
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2.4 Design and mode of operation
The swim system of the fill level limiter is contained in the fluid-filled reservoir
(expansion tank). The swimming motions generated by changes in the fill level
are transmitted directly to the micro-switch S1 by a swimmer rod sealed in a
stainless-steel bellows. The fulcrum of the swimmer rod is located outside of
the pressure chamber.
There is also a test button outside the pressure chamber with which a function
check as per DIN 4754-3 can be run without lowering the fill level. When
pressed, the body of the swimmer is moved against its buoyancy.
The factory default switching point of micro-switch S1 is set so that it switches
when the swimmer rod is horizontal. The optional warning switch S2 switches
approx. 2.5 mm before S1.
The fill level height at which switching is triggered depends on the density of the
heat carrier. The lowest density at which a secure function is guaranteed is 0.6
kg/dm³.
When the medium has a density of 1.0 kg/dm³, the switching level is approx.
60mm below the middle of the flange or socket.
