Improvement Of Proximity Sensor-Based Interlock System On Butterfly Valve And Danfoss Vlt Vfd Inverter To Prevent Screw Pump From Operating With The Valve Closed

Abstract

General Background Industrial piping networks utilize three-phase induction drives and isolation devices to ensure continuous and controlled fluid transfer. Specific Background Running a fluid transfer system against a closed discharge path generates trapped kinetic energy, rapidly increasing internal casing temperatures. Knowledge Gap Relying exclusively on manual observation for rotational valve positions frequently fails, causing severe mechanical failures and demanding automated, low-cost preventive solutions directly integrated into the drive control. Aims This study implements an automated inductive safety mechanism designed to block operation when the discharge path is obstructed. Results By mounting a metallic target and an inductive non-contact detector on the rotational handle, the mechanism reads the isolation device's physical orientation. This detection state is routed through a 24VDC relay directly to the variable frequency drive's push-button control line. Functional testing across three scenarios confirmed the drive was completely blocked during closed and half-open states, successfully preventing fluid entrapment and extreme heating. Novelty This system directly hardware-links an external mechanical position to a variable frequency drive's run-enable logic without requiring complex programmable controllers. Implications Deploying this straightforward, low-cost automated barrier successfully prevents severe component degradation, reduces downtime associated with human error, and secures continuous industrial workflows. Highlights: Running a fluid transfer system against a closed discharge path generates trapped kinetic energy, causing severe casing overheating. An inductive detector combined with a 24VDC relay intercepts the push-button signal to block the frequency drive. Hardware-linking mechanical isolation status directly to drive logic prevents extreme heating and component degradation. Keywords: Inductive Detector, Dead Head Prevention, Variable Frequency Drive, Preventive Maintenance, Mechanical Isolation