Ultimate 3000 RS Pump UHPL+ focused
The pump is a zero-pulsation, serial dual-piston pump with electronic compressibility compensation. The pump head includes two cylinders—working cylinder and equilibration cylinder—that are connected in series. The solvent passes both cylinders successively.
Continuous delivery is achieved as follows: The working cylinder delivers at the appropriate flow rate while simultaneously filling the serially connected equilibration cylinder. The latter serves as a reservoir and delivers while the working cylinder carries out the suction stroke.
The characteristic feature of the patented isokinetic pre-compression is the overlapping phase of the delivery strokes of the working and equilibration cylinders. When delivering compressible liquids without controlled pre-compression, the pulsation increases as the working pressure increases, since part of the delivery stroke is required for compressing the solvent in the working cylinder. Pulsation during the pre-compression phase is reduced to a minimum by velocity modulation of the drive. The highly constant delivery is ensured by a patented secondary control system (automatic compressibility compensation). The flow rate is always kept constant in relation to the atmospheric pressure.
Source: Thermo Scientific Dionex UltiMate 3000 Series SD, RS, BM, and BX Pumps Operating Instructions (Original Operating Instructions)