HR two-stage pusher centrifuges

HR two-stage pusher centrifuges

Principle of Operation

When the centrifuge is running at full speed, the suspension to be separated is fed through a feed pipe (or feed screw in the case of suspension with higher solid content) into the distributor installed on the outer basket. The suspension is evenly distributed on the screen inside the inner basket under centrifugal force. The liquid phase is discharged through the screen slots and the pores of the basket, while the solid phase is retained on the screen to form a stable filter cake ring. Through the oscillating motion of the inner basket, the filter cake moves forward along the axial direction of the basket and is discharged from the solids discharge channel at end of the outer basket.

Design of products

HR two-stage pusher centrifuges are supported on a frame through bearing assembly and mainly composed of oil pump assembly, pusher mechanism, frame, bearing assembly, basket, screen, and casing. For the 280/400/500 series, an oil cooler is installed inside the oil tank of the frame and the pump assembly is supported by the frame, with the oil pump inserted into the oil tank. For the 630/800/1000 series, an external oil cooler is used. The rotating assembly is connected to the rotor motor pulley through V-belts. The electric control box is a separate system, and the electric control cabinet is installed in the electric control room. The on-site operation box is installed in a suitable position near the centrifuge.

Special design features

The entire operation process is fully automatic and runs continuously without manual intervention. The machine is able to complete feeding, filtration, washing, dewatering, discharging and other steps at full speed, and suitable for the separation of concentrated suspensions containing crystal or short fibrous particles (solid content 30% -90%), with low particle breakage, filter cake washing available, large capacity, high solids recovery, low filter cake moisture, and low energy consumption. The technical parameters can be optimized for specific situations to better meet the needs of customers. The stroke frequency can be adjusted to better adapt to process changes. Pipe feeding or screw feeding can be selected for a wider range of applications according to different suspensions.

Applications

The centrifuge is suitable for separating suspensions containing crystal or short fibrous particles with good filtration properties. The average particle size of the solids is 0.08-3mm, with a concentration (volume ratio) of 30-80%, such as anilino acetonitrile, acrylamide, nickel acetate, acetate fiber, sodium dichromate, soda ash, succinic acid, paraxylene, wastewater salts, ammonium perchlorate, phosphate, sulfate, nitrate, ammonium chloride, potassium chloride, lithium chloride, ferrous chloride, potassium chlorate, chloroacetic acid, cotton seed, gelatin, urea, boric acid, lithium hydroxide, potassium carbonate, ammonium bicarbonate, potassium bicarbonate, urotropine, nitrocellulose, magnesium sulfite, sodium sulfite, sodium nitrite, aluminum oxide, and heavy alkali (secondary dewatering).

HR two-stage pusher centrifuge Standard Sizes and Technical Data 

The two-stage pusher centrifuge is an advanced industrial separation device designed for high-efficiency continuous solid-liquid separation in chemical, pharmaceutical, food, and mineral processing industries. It combines the advantages of traditional pusher centrifuges with an innovative two-stage design, ensuring higher throughput, improved cake washing, and optimal moisture reduction in solids. This centrifuge is engineered to handle a wide range of materials, including fine crystals, powders, and slurries with varying viscosities, particle sizes, and densities, making it a versatile solution for modern industrial processes.

Design Overview
The two-stage pusher centrifuge features a cylindrical rotating basket with a perforated drum that allows liquid to pass through while retaining solid particles. The two-stage pushing mechanism moves the solid cake stepwise along the drum, providing efficient discharge and improved washing capabilities. The first stage typically removes the bulk of the liquid from the wet solids, while the second stage ensures final moisture reduction and uniform cake consistency. The centrifuge is equipped with high-precision bearings, a durable drive system, and adjustable rotational speeds to match the specific requirements of each application.

Key Features and Benefits

Continuous High-Efficiency Operation:
The dual-stage pusher mechanism allows for continuous processing of solids and liquids, minimizing downtime and improving overall productivity. The stepwise pushing reduces cake compaction and prevents bridging, resulting in more uniform solid discharge.

Enhanced Cake Washing and Moisture Reduction:
The two-stage design facilitates thorough washing of solids with minimal liquid consumption. The first stage removes most interstitial liquid, while the second stage achieves precise moisture control, ensuring high-quality, dry cakes suitable for downstream processing.

Versatile Material Handling:
This centrifuge can process a wide range of particle sizes, densities, and viscosities. It is suitable for fine chemical crystals, pharmaceutical intermediates, food ingredients, and mineral slurries. Its gentle handling preserves product integrity while ensuring efficient separation.

Robust Construction and Reliability:
Designed for industrial use, the centrifuge features a heavy-duty drum, corrosion-resistant materials, and high-strength drive components. The robust construction ensures long service life even under harsh operating conditions.

Adjustable Process Parameters:
The rotational speed, push frequency, and feed rate can be optimized to meet specific process requirements. This flexibility allows operators to achieve maximum separation efficiency, minimize product loss, and control cake properties precisely.

Ease of Maintenance and Cleaning:
The centrifuge is designed with quick-access panels, removable parts, and smooth surfaces to facilitate routine maintenance, cleaning, and inspection. This reduces downtime and supports hygienic processing standards, especially in pharmaceutical and food industries.

Technical Specifications (Typical ranges, customizable by model)

Drum Diameter: 600–1500 mm

Drum Length: 1500–4000 mm

Capacity: 1–20 m³/h depending on material properties

Rotational Speed: 300–1200 rpm, adjustable

Cake Thickness: 30–150 mm per stage

Feed Concentration: 5–60% solids by weight

Temperature Range: Ambient to 100°C (higher with specialized materials)

Applications

Chemical Industry: Separation of fine chemical crystals, pigments, catalysts, and intermediates.

Pharmaceutical Industry: Recovery of active pharmaceutical ingredients (APIs), intermediates, and excipients with controlled moisture content.

Food Industry: Processing of starch, sugar, salts, proteins, and other edible crystals requiring efficient washing and moisture reduction.

Mineral Processing: Separation of fine mineral slurries, clay, talc, gypsum, and other powders requiring high throughput and uniform dryness.

Operating Principle
The wet slurry is continuously fed into the rotating drum, where centrifugal force separates solids from liquids. The solids form a cake on the inner surface of the drum, which is gradually pushed along the drum by the first-stage pusher. During this stage, the majority of free liquid is removed. In the second stage, the solids are compacted and washed with an appropriate liquid to remove impurities and achieve the desired moisture content. After the final stage, the solid cake is discharged continuously, while the clarified liquid exits through the perforated drum and collection system.

Advantages Over Single-Stage Pusher Centrifuges

Higher Throughput: The two-stage mechanism allows for faster cake transport and reduced cycle time.

Better Cake Quality: Improved washing and moisture control result in higher purity and uniformity.

Lower Liquid Consumption: Efficient washing reduces water or solvent usage, minimizing waste and operational costs.

Enhanced Reliability: Stepwise cake movement reduces mechanical stress on the drum and pushers, prolonging equipment life.

Maintenance and Safety Features

Heavy-duty, corrosion-resistant bearings and drive components for extended service life.

Removable and replaceable drum liners for easy maintenance.

Safety interlocks and automated shutdown systems to prevent operator injury.

Hygienic design options for pharmaceutical and food processing, including CIP (Clean-In-Place) capability.

Customization Options

Drum perforation patterns and sizes tailored to particle characteristics.

Material selection for corrosive or abrasive slurries (stainless steel, Hastelloy, or coated surfaces).

Integrated washing systems with multi-stage spray nozzles for optimized cake purity.

Automated control systems with sensors for feed rate, cake thickness, and moisture monitoring.

Conclusion
The two-stage pusher centrifuge is a reliable, high-performance solution for industries requiring continuous, efficient solid-liquid separation. Its innovative dual-stage design ensures optimal cake washing, uniform moisture control, and enhanced processing efficiency. With robust construction, flexible process control, and broad material compatibility, this centrifuge is an ideal choice for chemical, pharmaceutical, food, and mineral processing applications. By integrating a two-stage pusher centrifuge into production lines, manufacturers can achieve higher throughput, improved product quality, reduced liquid consumption, and greater operational reliability, making it a critical investment for modern industrial processes.