Cement Weigh Hopper Load Cell

Function

The cement load cell must resolve small incremental additions from the screw conveyor with a display resolution better than 0.5 kg on hoppers up to 500 kg capacity. It controls the screw conveyor cut-off relay, stopping cement delivery within the batch controller's in-flight compensation window. Sub-standard proportional accuracy or thermal drift translates directly into variable water-cement ratios and out-of-specification concrete — a quality and structural liability for the contractor and a source of cube test failure at the concrete laboratory.

Construction & quality

Cells are machined from stainless steel 17-4 PH (H900 condition) for full compatibility with the alkaline, hygroscopic cement dust environment. The strain-gauge bridge is hermetically sealed to IP68. A double-bridge arrangement improves temperature coefficient in thermally variable silo environments. Mounting is through precision-machined adaptor plates with anti-rotation keys to prevent side-load introduction. All cells are individually calibrated at a minimum of three load points and supplied with a calibration certificate traceable to national standards, recording linearity, hysteresis, and creep at 30 minutes.

When to replace

• Cement over-delivery or under-delivery confirmed by daily material reconciliation log
• Slow or frozen batch controller weight display during screw conveyor filling
• Zero drift exceeding 0.5 kg detected without weight change on hopper
• Visible cement caking on cell body or mounting adaptor restricting free hopper movement
• Calibration check showing sensitivity shift greater than 0.05% since last service