Tuning Fork Level Switches Utilized in Electrostatic Adsorption Materials

Tuning Fork Level Switch comprises a two fork tines which is driven by a piezo-crystal assembly to oscillate at its natural frequency. The fork sensors are typically factory calibrated and set at a specific frequency depending on the type of industry. When in air, the forks vibrate at their natural frequency; when solids cover the forks, the frequency of oscillation drops and is detected by the integrated circuit, which in turn changes the output state.

Tuning Fork Level Switches are utilized as overfill prevention mechanisms or low-level indicators in granular and powdered bulk solids. However, its adaptability should be taken into consideration in some applications.

There was a case that the client intended to measure iron powder, molybdenum powder, magnesium powder, aluminum powder and other metal powders in the plant, an amount of high level control level switches were required to mount on the silos. Because the metal powders have strong electrostatic adsorption properties, the level switches should be reliable and stable in the static electricity environment. The probe material of Tuning Fork Level Switch on the market is generally stainless-steel. When the probe rubs against the metal powders, the electrostatic adsorption phenomenon may affect the level measurement accuracy and output false alarm signals, results in flammable powder leakage, and even causes dust combustion and explosion accidents, as well as potentially putting the lives of workers at risk.

After deeper consultations on the client’s requirements, Jiwei engineer left behind a 0.03mm conducting anti-static coating (PTFE) on the surface of the forks that prevents static build-up. PTFE is an electrical insulating material without electrostatic adsorption property. The application proves that PTFE coating has excellent anti-static effect, plus Fork-11 Tuning Fork Level Switch has qualified for Explosion-Proof Certifications of Flameproof (Ex d IIC T6~T1 Gb) and Intrinsically Safe (Ex ia IIC T6~T1 Ga); the IP66/IP67 Protection Level and enclosures offer the highest protection against particles and a high level of protection against water, so Fork-11 Tuning Fork Level Switch is an ideal level switch for metal powder.