HLB-series Infusion pump/lab instrument is high tech composite including microprocessor system, stepping motor, divers, constant direct line movement mechanism, precision pump head, valve and other functional units. The constant flow pump is also called plunger pump, high performance liquid chromatography pump, and high pressure metering pump and reciprocating plunger pump. The series products have the advantages of precision adjusted flow, high pressure, constant velocity of flow, stable pressure, entering in various parameters with keyboard, LCD, direct read, convenient operation, anticorrosion, safe and reliable. The series design can provide the analysis and preparation pump for liquid chromatography, especially is applicable for choosing various controlled continuous of discontinuous infusion pump for constant, small or medial type test system.