水力旋流器作为一种常见的分离分级设备，其工作原理是离心沉降，当待分离的两相（或三相）混合液以一定压力从给矿口切线方向（或渐开线）进入旋流器后，产生强烈的三维椭圆型强旋转剪切旋流流动。由于粗颗粒（或重相）与细颗粒（或轻相）之间存在粒度差（或密度差），在离心力、向心力、浮力、流体阻力等作用下大部分粗颗粒（或重相）按螺旋轨迹下旋到底部，作为沉砂从沉砂口排出。细颗粒（轻相）在中心形成内螺旋矿流向上运动，作为溢流从溢流管排出。

All of the spinning action, and the resultant centrifugal force, is caused by the flow through the inlet branch being tangentical the feed box. Naturally, the higher the inlet pressure the greater the rotational speed and the greater the centrifugal force, which is commonly many times that of gravity. Solids are flung to the wall of the cyclone cone and spiral down to the spigot. The bulk of the liquid spirals upwards and leaves the cyclone through the vortex finder, the fraction leaving through the spigot being determined by the spigot to vortex finder relationship. The only solids to escape with the bulk of the water are the particles which are so fine that the entrainment or drag forces are not overcome by the centrifugal forces. Thus, for any given inlet pressure/rotational speed there is a cut size at which the drag and centrifugal forces are in balance. Particles finer than this cut size are dragged with the bulk of the liquid through the vortex finder, and particles coarser than the cut sixe report to the spigot.