Float level switches are devices used to detect the level of liquids within a container or tank by utilizing the buoyancy principle. When the liquid level rises or falls, the float attached to the switch moves accordingly, activating or deactivating the switch. There are several types of float level switches, each designed for specific applications and operating conditions:

1. Mechanical Float Switches:

   • These switches use a simple mechanical design consisting of a buoyant float attached to a lever arm or rod.
   • As the liquid level rises or falls, the float moves the lever arm, actuating a mechanical switch mechanism.
   • Mechanical float switches are commonly used in applications with relatively clean liquids and moderate temperature and pressure conditions.

2. Magnetic Float Switches:

   • Magnetic float switches utilize a float containing a magnet and a sensor or reed switch located outside the tank.
   • As the float moves with the liquid level, the magnet inside the float triggers the sensor or reed switch, causing it to change state.
   • These switches are often used in applications where contact between the sensor and the liquid is undesirable or where the tank walls are non-metallic.

3. Displacer Float Switches:

   • Displacer float switches use a buoyant object (displacer) that is heavier than the liquid being measured.
   • As the liquid level changes, the displacer moves up or down within a tube or chamber, causing the switch to activate or deactivate.
   • Displacer float switches are suitable for applications involving aggressive or viscous liquids and high-pressure conditions.

4. Cable Float Switches:

   • Cable float switches consist of a float attached to a flexible cable or tether, which is wound around a drum connected to a switch mechanism.
   • As the liquid level rises or falls, the float moves the cable, causing the drum to rotate and actuate the switch.
   • These switches are often used in narrow or deep tanks and applications with turbulent or foaming liquids.

5. Paddle Float Switches:

   • Paddle float switches feature a buoyant float attached to a pivoting arm with a paddle or vane.
   • When the liquid level rises, the float lifts the paddle, activating the switch. Conversely, when the level drops, the paddle falls, deactivating the switch.
   • Paddle float switches are suitable for applications with turbulent liquids or where precise level control is required.

6. Tuning Fork Float Switches:

   • Tuning fork float switches use a vibrating fork with a buoyant float attached to one end.
   • As the liquid level rises or falls, the buoyant float moves the fork, altering its resonant frequency.
   • The change in frequency is detected by electronics within the switch, which triggers the switch to change state.
   • These switches are often used in applications with highly viscous or sticky liquids and where reliability and accuracy are critical.

Each type of float level switch has its advantages and limitations, so it's essential to consider factors such as the type of liquid, operating conditions, installation requirements, and budget constraints when selecting the most suitable switch for a specific application.