Analytical HPLC pumps

Liquid chromatography pumps - Analytical HPLC pumps

A classic, double-head pump ACP 2 with miniature valves of 2.2-mm diameter made of sapphire monocrystal is earmarked in the Labio range for standard analytical applications. The ball valves (the inlet is doubled) are made from a combination sapphire - ruby.

Pistons are driven by shaped cams and held in place by means of springs. The camshaft is actuated by a stepping motor exhibiting a very large speed range from 1:1 to 1:10,000. Piston seals are made of a fluoroplastic material and reinforced by stainless steel. Piston heads included piston flushing possibility.

The ACP 2 pump is supplied in a smaller case of the same type as that used in PCP pumps and makes use of the identical display and keyboard. It can be also delivered in gradient design with a fluoroplastic, triple solenoid, small-volume valve that ensures high efficiency of component mixing. 

Microchromatography represents a promising but still not fully mature branch of HPLC. Pumps for microchromatography could be of the same type as analytical pumps - thanks to the use of stepping motors the units could operate with flowrates as low as microlitres per minute. However, owing to possible, even very small leakage of the ball valves they are in fact essentially useless here.

Labio, relying on the Czechoslovak tradition in designing single-piston, large-volume pumps, developed the Linar 30 pump. The volume of the cylinder in which the pump piston operates is 30 ml and is provided with a high-pressure solenoid valve at the inlet, which opens during the suction period, and an outlet ball valve. Linar 30 is equipped with a combined pressure gauge inclusive a bypass needle valve. The pressure sensor is situated in the rear part of the unit.

A steel piston with a front-end seal moves inside the cylinder, actuated by a low-friction ball screw and a high-performance stepping motor, which exhibits a very wide speed range and provides flowrates from 1 ul/min up to 2,000 ul/min, combined with a very rapid suction (1.5 minutes for the entire cylinder). Linar 30 is also supplied in a cabinet with plastic sidewalls and stainless-steel panels, a double-row display and a keyboard.