工业上用的超过滤及反渗透的微孔膜,需要具有相当高的耐压性和相当大的表面积。从制造与经济考虑,需要把大量的膜尽可能紧凑的排列在压力室里。为了避免微孔膜堵塞和极化,流体在膜表面上流动时需采用较大的流速,即为紊流状态,这样,截留在膜上的胶体直到分子大小的颗粒将被不断地从膜上冲下来。在这种横流过滤淡化装置里,流体总是连续流过膜,直至流体中的溶解物浓度增加到预定的限度。横流过滤淡化装置可采用圆盘形的过滤单元。在美国有排列为迷宫密封形式的过滤单元。在那种 Industrially used ultrafiltration and reverse osmosis microporous membranes need to have relatively high pressure resistance and a considerable surface area. From a manufacturing and economic point of view, it is necessary to arrange a large number of membranes in the pressure chamber as compactly as possible. In order to avoid clogging and polarization of the microporous membrane, a larger flow rate is required for the fluid to flow on the membrane surface, ie a turbulent state, so that the entrapment of colloids up to the molecular size of the particles will be continuously removed from the membrane. Rush down. In such a cross-flow filtration and desorption device, the fluid always flows continuously through the membrane until the concentration of dissolved substances in the fluid increases to a predetermined limit. The cross-flow filtration and desalination device may use a disc-shaped filter unit. In the United States there is a filter unit in the form of a labyrinth seal. In that kind