Center transmission concentrator small (diameter 1.8 ~ 20 meters diameter) and large (up to 100 meters in diameter phi) two. Small center drive type concentrators (Figure 10-L) by the thickener, the harrow frame, transmission device, signal safety device, harrow frame lifting device, a feeding device and a discharging device is composed.

The cylindrical thickening tank is made of cement or steel plate, and the bottom of the pool is conical or flat. At the bottom of the pool in the center of a hopper pool periphery of the upper part of a discharge concentrated product is provided with an annular groove along. In order to improve the efficiency of concentration. In a concentrated pool of Cheng fire area of lower, along around the pool with inclined plate, installation of inclined plate pulp is along the inclined board space obliquely upward movement, solid particles between the two inclined plate vertical settlement, settlement distance shortened, reduce the time, sink down to tilt in fine particles agglomerated together, consistent inclined to decline, the settling velocity is accelerated. After the installation of the inclined plate, but also increases the natural precipitation and accumulation of thickener.

There is a vertical shaft in the middle of the concentrated pool, and the end of the shaft is fixed with a cross shaped rake frame, and the lower drawing of the rake frame is provided with a scraper. Rake frame and horizontal plane 8~15. The vertical shaft is driven by a motor with a fixed on the truss by a cylindrical gear reducer, an intermediate gear and a worm gear reducer. When the shaft rotates, the pulp along the truss on the feed chute flow pool center by the barrel, and flow toward the preparing concentrated around him. Solid particles in the pulp gradually sink to the concentrated pool at the bottom. And the harrow frame below the scraper scraped into the pool to the center of the discharge hopper, discharged by the pump. The above clarified water from the Ikegami Be's ring overflow tank overflow.

In the operation process, we must pay attention to the concentration of the material. Overload thickener, or material is very concentrated qiaokuang, will cause the hopper blockage and harrow frame bending button. In order to prevent the overload safety device is provided with a signal concentrator, and rake lifting device. Signal safety device using mercury switch controller. One end of the worm is supported on the washer, the washer is a spring. When the load of the thickener is too large, too much sediment and the harrow frame in a rotating resistance is too large, worm thread by the pressure increases, make the worm along the axial movement, a compression spring praise, the gasket onto the right-hand. A contact is carried on the washer to make it contact with the eccentric mercury switch base. The switch seat is fixed with a mercury switch with three different dip angles. One of the following switch control is improved. The motor makes the rake stand down; the middle switch control the lifting motor to make the rake rise; the switch controls the driving part of the main motor.