The present invention relates to a membrane separation method and a relevant equipment, in particular to a method and an equipment for membrane separation utilizing concentration polarization during membrane filtration process, especially, to a concentration process and equipment and a drawer special for drawing a concentration polarization layer. A radial spring assembly is coupled between the primary mass and the secondary mass, as well as a latching assembly that can latch to selectively prevent relative rotation between the primary mass and the secondary mass. The light-pervious panel is provided on a front surface of the receiving unit and can be a transparent display panel with a touch control area.