Salt Rejection Down to 85% in Year Two? NL-ROM-4 RO Membrane Salt-Rejection and Recovery Bench (pump performance test), Four Stations

Acceptance for a water purifier is usually two checks: a TDS pen dipped in a cup, and a one-minute flow measurement. The complaints arrive in year two — scale back in the kettle, a filter change indicator that fires while the water still looks cloudy, the unit flushing more often than it used to. Salt rejection sliding from 96% to 85% is not a step the user can feel; it is scale coming back slowly. The difference between membranes hides in the coupling of three variables. The same element reads 96% rejection at 0.3 MPa and 25 °C, then 88% on a 0.15 MPa, 8 °C winter feed in the north. Press the recovery rate with a tighter concentrate ratio and the concentrate side scales faster, so decay arrives early. None of the three has a number on a conventional appliance test bench, and service can only swap cartridges and hope.

What the NL-ROM-4 salt-rejection and recovery bench measures

• Four stations on tempered, pressure-regulated feed: inlet temperature 5 to 35 °C and pressure 0.1 to 0.6 MPa set independently, reproducing both water qualities and all four seasons (the household booster-loop extension of our pump performance test range)
• Salt rejection: feed and permeate conductivity sampled together and temperature-corrected, logged per unit rather than spot-checked by hand
• Recovery and concentrate ratio: permeate and concentrate flows metered together, recovery computed against feed, concentrate ratio programmed and locked
• Pressure sweep: twenty points producing pressure-rejection-flux curves, so the knee of a given element is visible at a glance
• Temperature staging: 5, 15, 25 and 35 °C segments, the winter flux loss and rejection drop quantified as coefficients
• Spiked and hard-water duty: standard solution and hard water circulated, rejection and flux re-measured on a scaling cycle, decay curves plotted against run time
• Pre- and post-membrane differential pressure: fouling separated from concentrate-side scaling, the order in which pressure rise and rejection fall arrive made visible
• Flush recovery test: run-flush cycles with the rejection recovery ratio logged after each flush, separating reversible fouling from irreversible decay
• Barcode and batch binding, rejection, recovery, flux and differential pressure exported per unit for membrane and pre-filter lot comparison

Applicable standards

GB/T 30307 (household and similar drinking water treatment equipment), QB/T 4143 (household and similar reverse osmosis purifiers) and the rejection and recovery test basis of GB 34914 (minimum allowable values of water efficiency for water purifiers), with the safety side following GB 4706.1; feed conditions, spiked concentration and decay criteria can follow the customer standard, sampling to GB/T 2828.

Stations and throughput

Four stations running continuously on tempered feed turn “a TDS dip and a one-minute cup” into a full record of rejection curves, recovery, differential-pressure trend and flush recovery ratio. Incoming membranes, appliance builds, cartridge life calibration and after-sales dispute re-tests share one bench, moving the year-two rejection slide back onto the production line where it can be seen.

Manufacturer

Guangdong Endurance Electronic Equipment Co., Ltd. — a non-standard testing equipment manufacturer of RO membrane rejection and recovery benches, pump performance test systems, pump test bench ranges, 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.