The vibrating screening module is mainly used to separate coarse aggregate above 2 mm and fine aggregate and fine particles below 2 mm in the slag. Shenzhen Metro Line 14, Liuyao North Station shield pole slag processing site using two elliptical vibrating screen, a single 6000 mm long, 2160 mm wide, 2000 mm high, processing capacity of 120 ~ 160 m3 / h. Elliptical screen has a large excitation force, high screening efficiency, not easy to plug the hole characteristics. Each elliptical screen is equipped with three layers of screen mesh, and the size of its holes are 10 mm, 6 mm and 2 mm from large to small, and each layer of screen mesh is equipped with high-pressure spraying device at the top. The amplitude range, frequency range and excitation force are 8~9.5mm, 12.67~13.67 Hz and 200kN respectively for the type of sludge in the shield pole area. figure 3 shows the model diagram of the vibrating screen module. The smooth operation of the vibrating screen directly affects the processing efficiency of the system. This study solves the problem of conventional vibrating screen blockage with the following main features:
(1) additional feeding equipment to crush large pieces of sludge to ensure uniform feeding and loose characteristics to enhance the processing efficiency.
(2) set up multi-layer, adjustable high-pressure spraying device (such as Figure 4) on the vibrating screen, can be adjusted through the central control room active control spraying pressure, the pressure change range of 0.9 ~ 1.1 MPa; each layer of vibrating screen on the slag are over three spraying areas, of which the first area for high-pressure crushing area, the second area for flushing area, the third area for vibration drying area.
(3) vibrating screen configuration diamond-shaped anti-blocking screen, screen hole diameter 2 mm, to avoid blocking.
4）Vibrating screen amplitude, frequency and excitation force can be adjusted, which can greatly improve the processing capacity and geological adaptability.
5）Screen chute is set to assist in flushing.
(6) the customized steel junction vibrating screen bracket can be modularly assembled and moved, and the overall integration is high.
The sand washing module consists of sand washing impeller, hydrocyclone and dewatering screen, the main function is to separate fine aggregate between 0.075 mm and 2 mm and powder and sticky particles below 0.075 μm. In order to improve the efficiency of the sand washing module, it is optimally designed with two tandem impeller sand washers, four parallel hydrocyclones and one dewatering screen, of which the impeller diameter is 3.6 m and the cyclone diameter is 500 mm. Compared with the traditional equipment, the main features are as follows.
(1) vibrating screen sieve material directly into the sand washer, cyclone overflow material directly into the flocculation tank, sand washer main sand removal, cyclone auxiliary sand removal, to avoid the impact of cyclone work instability.
2）Adopt frequency conversion control impeller drive, through the central control room intelligent control impeller speed, reduce the risk of siltation.
3）Set up large flow overflow junction and high side water blocking sand washer to prevent water overflow and meet large flow sand washing.
(4) The cyclone bottom flow nozzle is of replaceable junction pole design to meet different sand washing needs.
5）The module is equipped with a distribution tank for controlling the flow rate of cyclone overflow mud and intelligently distributing the mud volume into each flocculation tank.
6）The steel junction required for the module is modularized, which is convenient for factory production and on-site assembling.
