what is theory behind on soxlet extration?

Soxhlet extraction is carried out when the desired compound has a limited solubility in a solvent,and the impurity is insoluble in that solvent. If the desired compound has a significant solubilityin a solvent then a simple filtration can be used to separate the compound from them insoluble substance.Soxhlet method is used to determine the lipid contents ofvarious oil-seeds. In principle, fat is extracted, semi continuously, with an organic solvent.Solvent is heated and volatized then is condensed above the sample.Solvent drips onto the sample and soaks it to extract the fat and at 15-20 min interval, the solvent is siphoned to the heating flask,to start the process again. Fat content is measured by weight loss of sample or weight of fat removed.