Flash pump are new, one piston, double action metering pumps specially designed for heavy conditions of preparative chromatography applications.
Flash pump are less sensitive to solid impurities in mobile phases than other pumps. The unique design results in nearly pulsless flow although pumps have one piston head only. Flow rate practically does not depend on outside pressure.
Flash pump are corrosion resistant as wet parts are made of HDPE (high density polyethylene), PEEK(polyetheretherketone), PTFE (polytetrefluorethylene) and AISI 316 stainless steel only.
Flash pumping head consist of a polished stainless steel cylinder with a piston inside. Piston front part is equipped with a ruff made of high density polyethylene. Piston rod has just half crossection in comparison with the cylinder and is sealed on back side of the cylinder with well-tried conical sealing which is known from CoMetro CP pumps line. On the bottom front part of the cylinder is located robust check valve with large ball inside. Output valve is created by piston ruff.
Flash pump head function is shown on Fig. 2. During the first stage of piston stroke (backward movement) is the liquid sucked through input valve to the front part of the head cylinder (A).
Liquid present in back part B is in the same time expeled from cylinder back space (B) to the system. In the second stage (piston forward movement) is the liquid from front cylinder space over pressed to the back as input valve is closed. Back space formed between the cylinder and piston rod expands in the same time, but quantity of the liquid transported from part is two times bigger than back side volume (due the crossections ratio). Thus in this stage is to the system displaced the same amount of the liquid as in the first one.
Flow rate is changed due the change of stores frequention i.e. Due the motor rotation speed change. Mechanical part of the pump changing rotation movement to the linear, is equipped with a cam; it is also taken from CP pumps line. All Flash pumps are placed in single block shaped box with a two line display and the keyboard on the front panel. Box is covered by U shaped stainless steel sheet. Inside of the box is situated motor, gearbox, cam mechanism, pressure gauge and electronics. Flow rate, time of the action and pressure limit are controlled from the keyboard, actual flow and pressure is monitored.