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Switch hysteresis: This refers to the distance travelled by the suspended body betweenthe switch-on and switch-off quantities. The typical hysteresis of the suspended body tube is attained by selecting reed switches with lower differences between the pick-up and drop-off activation levels (dose differential). Position-dependency: The unit must be installed vertically, i.e., the flow must be from thebottom to the top Installation in any position: By installing a spring which moves the suspended body into its initialposition, any installation position can be used. A re-adjustment is not required, as the springs have alredy been artificially aged and pre-tensioned. Viscosity compensation: This is achieved by installing a spring connected to a perforatedplate. As the spring has already been artificially aged, no re-adjust- ment is necessary. Maintenance note: Due to its design, the flow unit requires no maintenance. Cleaningat regular intervals should only be carried out in the case of media that contain magnetic particles. These cleaning intervals can be correspondingly extended by the use of a filter with a magnetic separator.

Level control instrumentation - 25885 Function and Principle of Operation

Areas of application: Monitoring of liquid and gaseous media, for example, in refrigerationsystems and refrigeration circuits of welding machines, laser and piping systems, pumps, compressors, hydraulic systems and many more. Principle of Operation: Switching point and switching range: Flow units work on the suspended body measurement principle.The suspended body is introduced into a cylindrical slotted nozzle. Depending on the model, the installation of the flow monitor is either dependent on its position (only with suspended bodies) orindependent of position (suspended bodies with spring). A reedswitch is connected, external to the flow circuit. The reed switch is sealed into a free-adjustable housing (switch housing) and is thereby protected from external influences. The incoming medium moves the suspended body in the direction of flow. If the suspended body, with its integrated magnets, reaches the position of the reed switch, the contact studs close. If the rate of flow becomes greater, the sus- pended body will move further in the direction of flow, with the maximum movement limited by a stop, which prevents the suspen- ded body moving beyond the switching area of the reed switch (bistable behaviour). The switching point can be continuously adjusted within the switching range. Corresponding to the flow speed present, the actual flow rate can be much larger than the maximum scale value (i.e., the maximum value on the scale can be exceeded). Wiring diagram: Notes on Installation: 1.1 Units dependent on position The flow monitor must be installed vertically in the system.2.1The flow must be from the bottomto the top. 1.2Units independent of position The flow monitor can be installed in thesystem in any position. 2.2The direction of flow must be such thatan increase in the flow produces a corresponding positive movement on the scale (i.e., from a lower to a higher reading). 1.3Viscosity compensated units The flow monitor can be installed in thesystem in any position. 2.3The direction of flow must be such thatan increase in the flow produces a corresponding positive movement on the scale (as above 2.2) 3.The medium must not carry any solid bodies with it. We recommend the in- stallation of a dirt trap of type SF, SFD or SFM.4.The unit with the contact device must not be located within an induction field.5.Always observe the maximum electrical values of the reed switch6.Setting the switching point:Set the arrow on the switch housing to the desired switch-off quantity on the scale of the unit housing.
normally open change-over 132 12 160