Float switch

Float switch are switching devices which are actuated by a moving fluid float.

  • 2.1 Level Switch
  • 2.2 echo level measurement

Purpose

Float switches are used for the automated control of liquid levels in liquid containers. Characteristic is the hysteresis between the on and off switching, resulting in corresponding fluctuations in level for each float switch.

Example

Thus, a float switch for example, open falls below a certain level, a valve to refill liquid in the container or turn it exceeds a certain level, a pump to lower the level.

Another typical application are submersible pumps, which are usually equipped with an electric float switch which switches off the drive on reaching a minimum level, in order to avoid running dry.

The most common types are float switches,

  • The float is fitted in a hermetically sealed housing with a ball that changes the position depending on the inclination due to the shift in focus to a given interconnect. Via a lever system, an electrical contact is activated.
  • Open a float switch sump pump

Float switch (off )

  • The float is guided and provided with a permanent magnet, the magnetic field a reed contact or a Hall sensor activated with an electronic trip circuit.
  • The float operated through a mechanical linkage an electrical switch.
  • The float acts directly on a valve, such as the carburetor of internal combustion engines, the so-called float needle valve or in the cistern of the toilet flushing, the float ball on the float valve.

Level switch

  • Level switches are actuated by a diaphragm by the pressure of a column of liquid. These level switches are frequently encountered in washing machines or dishwashers. A variant of the differential pressure switch with membrane then two media terminals.
  • Electronic level controllers assess the electrical resistance of a liquid column.

Echo level measurement

Echo level measurements even used for level control, but do not count as float switches. Based on the design principle there is the vibration limit switch as an alternative.

Hall effect sensor
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