Conductive level switches are devices used to detect the presence or absence of a conductive liquid at a certain level in a tank or vessel. These switches operate based on the principle of electrical conductivity and are commonly used in industrial applications for liquid level control and alarm functions. Here's how conductive level switches work:

1. Probe Installation:

   • Conductive level switches typically consist of one or more probes made of conductive material, such as stainless steel. The probes are installed vertically inside the tank or vessel at desired level points, such as high level, low level, or intermediate levels.

2. Electrical Circuit:

   • The conductive level switch is connected to an electrical circuit that includes a power supply and a relay or solid-state switch. When the liquid level reaches the level of the probes, it completes an electrical circuit between the probes, allowing current to flow through the liquid.

3. Detection of Conductivity:

   • When the liquid level rises to the level of the probes, it forms a conductive path between them. This completes the electrical circuit and allows current to flow from one probe to another through the conductive liquid. The presence of conductivity indicates that the liquid has reached the desired level.

4. Activation of Switch:

   • The completion of the electrical circuit triggers the switch mechanism in the conductive level switch. This can either open or close a relay or solid-state switch, depending on the design of the switch and the application requirements.

5. Control or Alarm Action:

   • The activation of the switch can be used to control other devices, such as pumps, valves, or alarms, based on the liquid level. For example, if the switch is configured as a high-level alarm, it can trigger an alarm signal or shut down a pump when the liquid level reaches a predetermined high level.

6. Deactivation and Reset:

   • When the liquid level falls below the level of the probes, the conductivity between the probes is interrupted, and the electrical circuit is broken. This deactivates the switch mechanism, and the switch returns to its normal state.

Conductive level switches are suitable for a wide range of conductive liquids, including water, acids, and bases. They offer advantages such as simplicity, reliability, and suitability for harsh or corrosive environments. However, they may not be suitable for non-conductive liquids or applications where precise level measurement is required. Additionally, factors such as fouling or coating of the probes can affect the performance of conductive level switches and should be considered during installation and maintenance.