JJF-20型浮选机的构造及其工作原理如何？它有什么特点？
Structure, working principle and characteristic of JJF-20 Flotation Separator
JJF-20 型浮选机是我国目前试制的最大的机械搅拌式浮选机。其结构与美国的维姆科（WEMCO ）浮选机相似。
JJF-20 Flotation Separator is the preproduction biggest mechanical flotation machine in our country now, its structure is alike to that of WEMCO Flotation Separator of the USA.
这种浮选机由叶轮（星形轮）、定子、分散罩、竖筒、主轴及轴承组成。在浮选机的槽底设置了假底与导流管装置。
This kind of Flotation Separator is composed of impeller (star-shaped impeller), stator, dispersion cover, vertical cylinder, main shaft and bearing. False bottom and honeycomb duct are installed at the bottom of Flotation Separator.
叶轮机构是浮选机的关键部件。
Impeller mechanism is the key part of flotation separator.
叶轮为星形，有放射状的 8 个叶片，叶片高 700 毫米，直径 φ700 毫米。
Impeller is star-shaped, it has 8 radial blades, height of blade is 700 mm. Diameter is 700 mm.
定子为圆筒形，圆筒周边有许多椭圆形小孔，内部有突出的筋条。
Stator is in cylinder shape, there are a lot of small elliptical holes around the cylinder and outbrust ribs inside it.
分散罩为截锥形，锥角 90 度，表面均布圆形小孔。
Dispersion cover is in truncated cone shape, cone angle is 90℃ and the surface is distributed with round small holes.
竖筒上有进气孔，空气经竖筒进入叶轮腔与矿浆混合。
There is air inlet on the vertical cylinder, and air enters into impeller cavity through vertical cylinder and mixes with pulp.
导流管装置在假底中心，其调节环与叶轮下端啮合 40 毫米，假底上有循环孔，供矿浆循环用。
Honeycomb duct is installed in the center of false bottom, its adjustable ring meshes with the lower end of impeller 40 mm, there is circulation port in false bottom used for pulp circulation.
其工作原理：叶轮在定子中回转时，其邻近的矿浆产生液体旋涡，形成负压，空气由竖筒盖上的吸气孔引入，与此同时，矿浆从槽底通过导流管向上进入叶片间的空间，并与吸入的空气混合，经叶轮的离心力作用，三相混合物离开叶轮叶片通过圆筒形定子表面的通道和分散罩上均匀分布的小孔进入浮选区，浮选的分离过程则在此区完成，矿浆返回槽底再循环，矿化泡沫上升到泡沫区由刮板刮出成为泡沫产品（精矿或中矿）。
Its working principle: when impeller rotates in stator, pulp close to it produces liquid vortex and forms negative pressure, and air enters from the suction hole on the cover of vertical cylinder, at the same time, pulp enters into the clearance of blade through honeycomb duct from the bottom of groove and mixes with sucted air, under the action of impeller’s centrifugal force, three-phase mixtures leaves blade of impeller and enter into flotation separating area through the passage on the surface of cylindrical stator and small holes evenly distributed on the dispersion cover, separating process of flotation is finished in this area. Pulp returns to the bottom of groove and recycle, mineralized froth raises to foam area and is scraped out by scraper and becomes foam product (concentrate or middling ore).
此类型浮选机有以下特点：
This kind of flotation separator has the following charateristics:
（1）它是自吸气机械搅拌式结构，所以能够自吸足够量的空气，搅拌能力也比较强。
（2）有一个相对稳定的分离区，矿液面稳定。
（3）叶轮与定子的间隙较大（230 毫米），叶轮的圆周速度低（6.6 米/秒），这就减少了叶轮与定子的磨损，并可降低电能消耗。
(1)Its structure is self-inspiration mechanical agitation type, so it can inspirate enough air by itself and has a strong agitating capacity.
(2)It has a relatively steady separating area and mine liquid level is steady.
(3)Clearance between impeller and stator is large (230 mm), circumferential velocity of impeller is low (6.6 m/s), which redeuce the wear between impeller and stator and electric energy consumption.
该浮选机主要缺点是不能自吸矿浆， 是自流式给矿。 当槽数配置多于六槽时， 则需采用阶梯配置，中矿返回需要泡沫泵。
Main disadvantage of this flotation separator: it cannot inspirate pulp by itself and it is gravity flow type ore feeding. When allocation of groove number is more than six grooves, it needs to adopt stepped allocation and middling recurrence needs foam pump.
