Equipment for a series of membrane separation operations such as ultrafiltration, reverse osmosis, gas permeation separation, dialysis, electrodialysis and liquid membrane separation. Due to the configuration of the membrane and the separation process has its own characteristics, there are many types of equipment. Sometimes according to the process purpose or use, respectively, known as ultra-filter, permeator, dialyzer, electrodialyzer or desalinator, etc., and its future development trend for automation, simplicity.