Two-Stage Pusher Centrifuge

Zhejiang-EscherWyss Two-stage Pusher Centrifuge is China's only product manufactured under the licence and whole technology from Swiss Sulzer Escher Wyss

Process
The pusher centrifuge utilizes continuous filtration to separate suspended, fast-draining, crystalline, granular, or fibrous solids from the liquid phase. The solids can be washed as they are transported through the basket.

Application
Pusher centrifuges are widely used in various fields for the separation of slurries with easily filterable solids.

Typical Products
Chemicals: Glaubers salt, salt, boric acid, ascorbic acid, adipic acid, sodium chloride, iron sulphate, sodium sulphate, copper sulphate, sodium bichromate.
Fertilizers: Ammonium sulphate, potash, urea, calcium nitrate, potassium sulphate.
Food stuff and animal feeds: Extraction residues, meat pulp.
Benefication: Rock phosphate, gypsum, ores, coal.

Mode of Operation
(1) Feeding:
Slurries are fed via a feed pipe—non-flowable products are conveyed via a screw—into the feed distributor, which rotates at basket speed. Here, the feed is accelerated and evenly distributed over the screen.

(2) Filtration and Transport:
The majority of the liquid is drained at the feed zone of the slot screen and is discharged into the filtrate housing, while the solids form a cake that is moved axially into the solids discharge housing by the oscillating pusher plate. During this axial movement, the solids are dewatered to low final moisture. In single-stage baskets, the cake moves over the screen, while in two-stage baskets, a combination of an oscillating inner basket and a stationary pusher plate is used for cake movement.

(3) Filtrate Removal:
Due to ventilation from the rotating baskets, the filtrate is usually mixed with air. For this reason, we recommend venting at the filtrate outlet flange. The filtrate housing can be subdivided by partitions to separate main filtrate and wash filtrate. An efficient separation can be expected, even for counter-current wash systems, specifically with single-stage units. The filtrate outlet can be directed downwards, or to the right or left of the centerline, depending on the direction of basket rotation.

(4) Cake Washing:
The solids layer on the screen can be washed using nozzles or a wash basket.

(5) Discharge of Solids:
The cake is discharged from the basket into the solids collecting housing or into a volute race at peripheral speed. This allows direct conveyance of the solids to the dryer.

Design Concepts
Complete separation of the mechanical unit from the process area. Long and short baskets.