The reverse osmosis device is an equipment to purify the salty water through pressure by semi-permeable membrane. It is contrary to the natural osmosis, so it is called reverse osmosis. Different materials have different osmosis pressures, the function of reverse osmosis is to separate,extract, purify and condense through the pressure, which is larger than osmotic pressure. More than 97% soluble salts and 99% colloid microbe, particulate and organic substances etc. can be removed through reverse osmosis. It becomes the most ideal method for the modern pure water, high pure water and ultra pure water.It is featured by low consumption, ow contamination, simple technical process, high water quality, easy maintenance and repair.