The most known and simple level switch consists of a float which is mounted on a moveable arm and magnetically coupled to a micro switch (outside the process).
Also versions exist with a spherical float, which contains a small magnet and move upwards a tube. In the tube one or more reed relays are placed.
The reed relays will switch as the (magnetic) float passes by.
The image below shows a simple float type mechanism.
Advantages of Float level switch
- Relatively simple.
- It is suitable for various products
- Low cost.
Disadvantages of Float level switch
- Requires a certain mounting
- No reproduction switch point
- There is a malfunction in case of build-up.
- It is not fail-safe.