Paddle Switch Level Measurement

Paddle Switch Level Measurement

Paddle switch devices are electromechanical point level switches intended for bulk solids in silos and hoppers. They are widely applied for full, empty, and demand alarms where a simple, rugged switch point is sufficient. Because the principle is mechanical and direct, paddle switches remain common in bulk handling environments where straightforward alarming and minimal configuration effort are prioritized.

The measuring principle uses a rotating paddle driven by a motor. When bulk solids cover the paddle, rotation is stopped; this stall condition actuates an internal relay to generate a discrete signal. The approach is typically implemented without calibration, making commissioning fast and repeatable across similar assets.

Benefits include suitability for many standard bulk solid services and robust mechanical packaging. Variants are available for different installation needs, with compact housings that fit common silo nozzle arrangements. Designs are noted as appropriate for dust explosive areas when configured with suitable construction, and can be applied to flowing bulk solids up to specified grain sizes (application-dependent). This makes paddle switches a practical solution for widely distributed bins and silos.

Typical applications include grain and feed silos, plastic pellets and granulates, powders, and other free-flowing solids where a discrete high/low point is needed for alarms or interlocks. Common functions include high-level protection at fill points, low-level alarms for feeder starvation prevention, and “demand” alarms to trigger replenishment. They are also used in intermediate hoppers feeding process lines where a reliable solids-present signal supports stable operation.

Engineering considerations include bulk density, particle size, and abrasion. Because a moving paddle interacts with solids, extremely abrasive materials or high mechanical loads can affect wear rates and should be evaluated. Mounting location should avoid dead zones and bridging-prone regions to prevent false states. When applied within the mechanical limits of the process, paddle switches provide a dependable and economical point level layer for bulk solids storage and handling.

Instrumentation and Controls., an exclusive authorized representative of sales and service for Endress+Hauser.