The degasser module is usually placed in between the solvent cabinet and the pump.
Its function is to remove any gas that might be dissolved into the solvent before it reaches the pump and enters the system, so as to reduce the pressure ripple and improve the repeatability of the analysis.
The solvent should also undergo sonification to further reduce gas presence. Sonification of the solvent shouldn’t be seen as a replacement for the use of a degasser, as it will result in a loss of quality in the results.