Liquid Chromatography - The Low Pressure Programmer
The Low Pressure Programmer
In a low pressure programmer, the solvent from each reservoir passes to an oscillating valve, the output from which is connected to a mixing manifold. A diagram of the layout of a typical low-pressure solvent programmer is shown in figure 3.
Figure 3. A Low Pressure Solvent Programmer
The manifold receives and mixes solvents from each of the programmed valves. The valves are electrically operated and programmed to open and close for different periods of time by adjusting the frequency and wave form of the supply. Thus, a pre-determined amount of each solvent is allowed to flow into the manifold. The valves can also be driven either by oscillators contained in a separate electronic programmer or by the chromatograph computer which modifies the wave form and frequency to control the flow of each solvent.