This refurbished HP 1050 Quat Pump is in very good condition. We are professionals. Hydraulic system. Pistons connected twice in series with self-servo-controlled, variable stroke drive, floating pistons and active inlet valves. Flow range. Setpoint from 0.001 to 9.999 ml/min in 0.001 ml/min increments. Piston displacement. 20 to 100 µL, automatically adjusted to flow or user selectable. Flow precision. <0.3% RSD (typically <0.15%) based on retention time at 0.5 mL/min and 2.5 mL/min. Pressure. Operating range from 0-400 bar (5880 psi) up to 5 ml/min; from 0-200 bar (2950 psi) up to 10 ml/min. Display in bar, psi or MPa. Pressure pulsation. <2% amplitude (typically <1%), 1 ml/min isopropanol at all pressures >10 bar. Compressibility compensation. User-selectable depending on the compressibility of the mobile phase. Recommended pH range. 2.3 to 12.5 (stainless steel version). Solvents with a pH value below 2.3 should not contain acids that attack stainless steel. 1.0 to 14 (TI series). Gradient formation. Low pressure quaternary mixing/gradient capability through use of an inherently rapid proportioning valve. Delay volume. 900 to 1100 µl depending on the back pressure. Composition range. 0 to 100% in 0.1% steps from four independent channels. Composition precision. ±0.25% absolute (typically ±0.15%) peak to peak, binary mixed water/acetonitrile from 0.5 ml/min to 5.0 ml/min without mixer. Solvent preparation. Four 1 liter bottles, each with individually regulated helium injection, cap and filter. Oven temperature range. Ambient temperature +5°C to ambient temperature +60°C in 0.1°C increments. Display in °C, °F or K. Oven temperature stability. ±0.15°C. Oven capacity. Two 25cm or three 20cm columns. Steering. Integrated keyboard with function keys; Parameter editing possible during the run; keyboard lock; optional PC control. Parameter. Flow rate, compressibility, piston stroke volume, upper and lower pressure limits, 2 external contacts; %B, %C, %D (for quaternary pump). Time programmable parameters: flow rate, upper pressure limit, external contacts; %B, %C, %D. Methods. Battery-backed storage of up to 10 methods. Automatic start and shutdown methods. Editing of saved methods possible during the run. Analogue output. For pressure monitoring, 2 mV/bar. Communication. Outputs: Ready signal and two external outputs (a 24V relay and a 30V (AC/DC) contact shutter, both 0.25A). Inputs and outputs: start, stop and shutdown signals. Optional interface for GPIB and RS-232C. Safety aids. Comprehensive diagnostics, error detection and display via front panel LEDs and status log. Custom shutdown method enabled in case of error. Leak detection and safe leak treatment. Low voltages in key maintenance areas. Column pressure protection with a maximum pressure change rate of <20 bar/second after a setpoint change. Vicinity. 4°C to 55°C (constant temperature) at <95% humidity (non-condensing). Power requirements. Mains voltage: 100-120 or 220-240 VAC ±10% Labprocure is responsible for this device.