After the rotating drum runs at full speed, the suspension enters the conical hopper mounted on the pusher plate through the feed pipe. Under the action of centrifugal force, the suspension enters the rotating drum evenly through the hopper. The filtrate is thrown out of the drum through the screen mesh gaps and the filter holes on the drum wall, and the solid phase is retained on the screen to form a cylindrical filter cake layer. The pusher plate makes a reciprocating movement controlled by a hydraulic system. When the pusher plate moves forward, the filter cake layer is pushed forward a certain distance. After the pusher plate moves backward, a new filter cake layer is formed on the empty screen. Due to the continuous reciprocating movement of the pusher plate, the filter cake layer is continuously pushed forward along the axis of the drum wall and finally discharged from the drum through the discharge port of the casing. The liquid phase is collected in the casing and discharged through the discharge port at the bottom or side of the casing.

If the filter cake needs to be washed in the machine, the washing liquid can be continuously sprayed onto the filter cake layer through a washing liquid pipe or other washing equipment, and the washing liquid and separated liquid are discharged together through the discharge port.

The structural types of horizontal piston pusher centrifuges can be divided into: horizontal single-stage piston pusher centrifuges, horizontal two-stage piston pusher centrifuges, and horizontal column/cone two-stage piston pusher centrifuges, etc.

To improve the separation effect of the piston pusher centrifuge, the residence time of the material to be separated in the drum must be ensured. Therefore, the drum of a single-stage piston pusher centrifuge should have sufficient length. However, as the drum length increases, the resistance to pushing the filter cake layer also increases, and the filter cake layer may arch or accumulate due to insufficient thickness, thus destroying the separation, washing, and normal discharge of the filter cake. To prevent the filter cake layer from exhibiting the above phenomena, the thickness of the filter cake layer must be ensured while increasing the drum length. However, this will reduce the dehydration and washing effect of the centrifuge, so the drum length cannot be increased indefinitely.

Because the horizontal two-stage piston pusher centrifuge has a double-stage drum, each drum can be shortened, while the total length of the two drums is greater than the drum length of the single-stage piston pusher centrifuge. Therefore, when ensuring the same filter cake residence time, the filter cake layer can be correspondingly thinned, and the filter cake is loosened when it is pushed from the upper drum to the lower drum, which is conducive to improving the separation, dehydration, and washing effects. The horizontal two-stage piston pusher centrifuge can effectively improve the separation factor of the centrifuge and increase the filtration driving force. Compared with the horizontal single-stage piston pusher centrifuge, the horizontal two-stage piston pusher centrifuge has advantages such as a wide range of applications, low filter cake moisture content, thorough washing, and low unit energy consumption.

The small drum of the horizontal column/cone two-stage piston pusher centrifuge is cylindrical, and the large drum, i.e., the secondary drum, is column/cone shaped. When the filter cake loses some water in the primary drum and enters the secondary column/cone drum, it is not only loosened, but also when the filter cake enters the conical part of the secondary drum, the filter cake layer becomes thinner as the radius increases, resulting in a better dehydration effect. In the separation process of this centrifuge, separation, dehydration, and re-dehydration can be achieved. Therefore, when using a horizontal column/cone two-stage piston pusher centrifuge to separate a liquid-solid mixture, the final filter cake moisture content is 2%~4% lower than that of an ordinary two-stage piston pusher centrifuge, and the output can be increased by 20%~30%, correspondingly reducing the unit energy consumption.

① Under the condition of determining the use of a filter centrifuge, if continuous operation and large output are required, a horizontal piston pusher centrifuge should be selected.

② Materials with a mass fraction of 30%~80% of suspension can be selected using a horizontal piston pusher centrifuge. The higher the solid content in the suspension, the greater the production capacity. In actual production, materials with low concentration can use pre-concentration equipment, such as a hydrocyclone, sedimentation tank, thickener, or a pre-concentration device added to the piston pusher centrifuge itself, to meet the separation requirements of the horizontal piston pusher centrifuge.

③ The larger the size of the solid particles of the material processed by the horizontal piston pusher centrifuge, the better. The crystal particles are required to have a certain shape and maintain sufficient drainage channels under the action of centrifugal force. The horizontal piston pusher centrifuge requires that the average particle size of the material crystals should be greater than 180 μm, and the material viscosity should be less than 0.1 Pa·S. When higher requirements are placed on the filter cake moisture content or the washing of the filter cake, a horizontal two-stage piston pusher centrifuge or a column/cone two-stage piston pusher centrifuge can be selected.

④ The possibility of crystal breakage in a horizontal piston pusher centrifuge is relatively high. For products with strict requirements on crystal particle size and shape, the selection of this equipment should be carefully considered.

⑤ The horizontal piston pusher centrifuge has certain requirements for the strength of the filter cake. When the consolidation strength of the filter cake layer is insufficient, it will cause the filter cake to bulge and accumulate, resulting in abnormal operation of the equipment.

⑥ Two-stage piston pusher centrifuges are suitable for separating suspensions of medium-sized crystalline or short-fiber materials, especially those that need to be washed in the machine. The requirements for materials of horizontal two-stage piston pusher centrifuges are not as strict as those of single-stage piston pusher centrifuges, but the feed concentration must be stable and uniform, and the average particle size of the solid phase is 0.1~3 mm.

⑦ Horizontal column/cone two-stage piston pusher centrifuges are suitable for separating materials separated by ordinary horizontal two-stage piston pusher centrifuges, and are also suitable for separating fine crystalline particles. The requirements for feed concentration and temperature are the same as those for horizontal single-stage and two-stage piston pusher centrifuges.