However the most important requirement is reliability to avoid losses and dangers. Mechanical low cost alternatives such as rotary paddle switches have been used and replaced for decades in many applications. Their main limitations are the wear and tear of mechanical parts (motor, blade, probe sealing). They rarely have a testing mechanism against malfunctioning. Failure is often discovered by overspilling, etc. Short life cycles cause high maintenance and replacement cost.

Capacitance probes are a compelling choice for both solids and liquid switching applications. They function by creating a low-voltage, high-frequency signal along the probe, creating a small current flow between the probe tip and the ground plane. As the level of the measured material comes into contact with the probe, this alters the capacitance measurement between probe and ground plane, which triggers an alert for the user.

Modern capacitance units such as Hycontrol’s ME Series use the same transmitter and sensor for all applications with adjustable sensitivity on the dielectric constant. The initial cost is higher compared to mechanical switches. However they have the functional lifetime of several rotary switches, improved reliability and reduced maintenance costs. In most cases, once the probe has been installed, wired and calibrated (a relatively simple adjustment), users can effectively forget about it.

Capacitance switches have limitation for stickier products which may coat the probe over time causing reduced sensitivity and regular maintenance service.

Capacitance probes are durable and flexible devices that can be mounted from the top, side, or bottom of a vessel, and allow for reliable monitoring of a wide range of products across a variety of industries.

Features:

• 

  Easy installation through a 1” BSP process fitting
• High corrosion and chemical resistance as standard options
• Universal design can be used for high or low level detection
• Failsafe options high and low selectable
• Multiple versions with rod and cable to simplify mounting options
• High temperature versions up to 800°C
• Low maintenance technology with no moving parts
• Hazardous area certified versions ATEX-approved
• Adjustable sensitivity for a wide range of products
• Adjustable time delay to stop spurious signals from surface ripple
• Anti-static probes for plastic pellet applications with high static probability
• Remote electronics option for high vibration applications
• Interface level detection for difficult applications

ME Capacitance Product Range

PDF Capacitance Level Switches