mechanism should perform the mixing the solution should be thoroughly stirred until there is no sign of any solid powder the solution usually is filtered through a fine mesh and then pulled into a degassing vessel by a vacuum pump the air is then let in which compresses the solution this process is repeated until there is no rise of the liquid surface because of de gassing under vacuum the pre mixed solution has a fairly good shelf life if it is kept sealed to avoid any moisture penetration if fabric is to be coated the fabric is pre cleaned and all the particles and unwanted fine fibers sticking out are removed the fabric is loaded on a knife coating machine to be coated the solution of pvdf is fed to the knife coater as the fabric is pulled through it the fabric is coated to a pre determined thickness that may be automatically controlled the coated fabric is then dipped into the non solvent solution the fabric is soaked long enough to thoroughly remove most of the solvent and is then fed into a drying channel under tension after that it is ready for more treatment such as the addition of a hydrophilic coating a net structure or a spray on a water repellent such as u201c scotchgard u201d u00ae the fabric can then be rolled up for shipment or storage the non solvent is water and the solvent is for example dmso or dmac this causes a reduction of the surface tension of the non solvent and so of the diffusion rate of the solvent from the solution the.