Paddle Switch Level Measurement

Paddle Switch Level Measurement

Paddle switch level measurement is an electromechanical point level detection method for bulk solids. It is designed to provide discrete “full,” “empty,” or demand alarms in silos and bins using a rotating paddle that responds to material presence. The approach is popular for straightforward solids applications where a rugged, easy-to-apply switch is required.

The measuring principle is direct: a motor drives a paddle to rotate freely in air. When bulk material covers the paddle, rotation is impeded or stopped; the resulting torque change actuates an internal switching mechanism (typically a relay output). Because the device detects mechanical resistance, it functions well as a presence indicator in many granular and powdered products without complex setup.

The major benefits are simplicity and minimal configuration effort - many installations require no calibration. Paddle switches can be cost-effective for basic alarm duties and can be built with robust housings and materials suited to industrial solids handling. They are often applied in dusty environments, including installations that require appropriate protection measures for dust-explosive atmospheres.

Typical applications include high- and low-level alarms in storage silos, demand indication to initiate refill, and bin level monitoring in food and beverage solids, pulp and paper, and mining/minerals. They are commonly used on flowing bulk solids such as grains and similar products, and can be effective where the bulk material reliably engages the paddle.

Selection should consider bulk density, particle size, stickiness, and the likelihood of bridging or ratholing. Installation location matters: placement in zones of consistent material movement improves reliability, while mounting near fill streams or severe build-up areas can shorten service life. Mechanical wear, motor duty, and access for inspection should be accounted for in maintenance planning, especially in continuous-duty solids systems.

Forberg Smith, an exclusive authorized representative of sales and service for Endress+Hauser.