This process makes use of a trans-membrane pressure for the purpose of separating particles according to their molecular weights. Here, hollow fibers ultrafiltration system (UFS) membranes act as the medium of filtration and they allow only those particles to permeate through that are larger than the membranes' pore size. These membranes are made up of high molecular material using special and sophisticated technology. The pore size ranges from 0.1 to 0.005 μm (200,000 to 10,000 Daltons)for various applications.