Leveltrol is a type of pneumatic level measurement and control system commonly used in industrial applications to monitor and maintain liquid levels in tanks or vessels. It operates based on the principle of buoyancy and pneumatic control. Here's how the Leveltrol system works:

1. Installation of the Leveltrol System:

   • The Leveltrol system consists of a level sensing device (such as a displacer or float) installed inside the tank or vessel, pneumatic tubing, control valves, and a pneumatic controller.
   • The level sensing device is typically connected to a displacer extension arm or float arm, which extends vertically from the top of the tank to the liquid surface.

2. Level Sensing Mechanism:

   • As the liquid level in the tank changes, the displacer or float attached to the level sensing device moves up or down with the liquid surface. This movement is transmitted through the displacer or float arm.

3. Pneumatic Control System:

   • The Leveltrol system uses pneumatic pressure to control the liquid level in the tank. It consists of a pneumatic controller, which receives input signals from the level sensing device and adjusts the flow of compressed air or gas to control valves.

4. Pressure Measurement:

   • The pneumatic controller measures the pressure in the pneumatic tubing connected to the level sensing device. As the displacer or float moves with the liquid level, it causes changes in pressure within the pneumatic tubing.

5. Control Valve Operation:

   • Based on the pressure measurements received from the level sensing device, the pneumatic controller adjusts the opening or closing of control valves in the pneumatic circuit.
   • When the liquid level rises above the desired setpoint, the pneumatic controller signals the control valves to open, allowing compressed air or gas to flow into the tank, displacing the liquid and lowering the level.
   • Conversely, when the liquid level falls below the setpoint, the pneumatic controller signals the control valves to close, reducing the flow of compressed air or gas into the tank and allowing the liquid level to rise.

6. Feedback Control Loop:

   • The Leveltrol system operates in a closed-loop feedback control system, continuously monitoring the liquid level and adjusting the control valves to maintain the level within a specified range.
   • The level sensing device provides feedback to the pneumatic controller, allowing it to make precise adjustments to the control valves based on changes in the liquid level.

Overall, the Leveltrol system provides accurate and reliable level measurement and control in industrial applications, ensuring optimal process efficiency and safety. It is commonly used in chemical processing plants, refineries, power plants, water treatment facilities, and other process industries where precise liquid level control is critical.