Circulation Pump Losing Flow to Cavitation and Burning Out After a Few Dry Runs? NL-CAV-4 NPSH and Dry-Run Protection Bench Maps Both Curves on Eight Stations (pump test bench)

Circulation and booster pumps that lose thirty percent of their flow once fitted to a machine, hiss like rolling gravel, and show a honeycombed impeller when opened up — or burn out after a few dry runs when the tank empties — are the two items most often skipped in pump selection and incoming inspection at water-purifier, dishwasher and hot-water-loop plants. The cause is usually insufficient net positive suction head from an undersized inlet path, poor cavitation resistance in the impeller material and passage design, and a dry-run protection trip point set too high. Trial fitting on a machine tells you nothing about the critical point, and the problem only surfaces as a batch of warranty returns.

What the NL-CAV-4 pump cavitation and dry-run protection bench measures

• Eight stations in parallel, NPSHr determination: inlet pressure lowered step by step until head drops 3%, with the critical NPSH logged automatically on our in-house pump test bench platform with the same vacuum regulation and flow metering
• Full H-Q and efficiency curves swept automatically, with pump performance test data exported in one click
• Before-and-after comparison of flow, head, efficiency and noise to quantify impeller cavitation resistance
• Dry-run protection testing: dry running simulated, with winding temperature rise, trip time and reset reliability recorded to reproduce dry-run burnout
• Mechanical seal and port leakage pressure-hold testing to assess long-term seepage risk
• Vibration and noise spectrum capture, with barcode and batch binding and raw data filed per unit

Applicable standards

GB/T 3216 (rotodynamic pumps – hydraulic performance acceptance tests, grades 1, 2 and 3), ISO 9906 (rotodynamic pumps – hydraulic performance acceptance tests), GB/T 12785 (submersible motor-pump units – test methods) and GB/T 2828 sampling; criteria can follow the customer’s standard and the unit’s flow and head requirements.

Stations and throughput

Eight stations running 24/7 compress the half day an operator would spend plumbing a rig, closing valves point by point and reading gauges into a dozen minutes per pump, with NPSH curves and dry-run temperature rise rechecked cycle by cycle — so incoming pumps and end-of-line machines can both be sampled batch by batch, stopping low flow and dry-run burnout before shipment.

Manufacturer

Guangdong Endurance Electronic Equipment Co., Ltd. — a non-standard testing equipment manufacturer of pump cavitation and dry-run protection benches, pump test bench and pump performance test systems, level sensor life test machines, dishwasher test equipment and washing machine test equipment.

Keywords: pump test bench, pump performance test, level sensor life test, dishwasher test equipment, washing machine test equipment.