Vertical Basket Centrifuge – Top Discharge

The Vertical Basket Centrifuge with Top Discharge offers simple yet efficient filtration (solid/liquid separation) of fine chemicals or Active Pharmaceutical Ingredients (API).

It is used for products that need a large filtering surface and very frequent product changes, due to its simple operation and cleaning procedures. This is the least closed environment because the unit is opened for product removal, therefore additional measures may need to be taken for containment.

Production Cycle and Design Advantages

Overview

Feeding

The solid-liquid suspension is fed through the feed pipe into the centrifuge. It moves towards the filter cloth under the action of centrifugal force, and onto on a perforated drum. The solid part of the suspension is retained by the filter cloth, forming a cake, while the liquid filters through the cake. The liquid is discharged through the holes of the basket. The growth of the cake thickness is controlled by a mechanical paddle detector, which can automatically stop the feeding phase when the desired cake thickness is reached.

Cake Washing

Cake washing removes any impurities present in the cake. The washing liquid is distributed onto the product in the basket, and through nozzles located along the washing pipe. The liquid passes through the product, then passes from the filter bag and the holes of the basket, removing impurities present in the cake.

Centrifugation

Once the washing phase is complete, the centrifuge accelerates to the maximum speed allowable for the product being processed, and maintains that speed for a given amount of time to achieve the desired level of residual humidity in the product. At the end of the centrifugation, the centrifuge is stopped to discharge the product.

Discharge

The solids discharge can be achieved manually by means of: a shovel (Alfa/B), a lifting bag system (Alfa/SB), or automatically via a scraping knife/vacuum (Alfa/B-CA).

Typical Applications

Fine chemicals
Pharmaceuticals
API

Highlights

Batch filtering centrifuge with product discharge from the top
Fixed frame or GMP design available
Full inspection of process area and flat basket bottom is possible with GMP design
Glove box operation (for high containment) is available
Production of chemical and pharmaceutical products from synthesis processes
Suitable for products requiring a large filtering surface area
Simple operation and cleaning procedures allow for frequent change of production

Discharge Versions

ALFA/B: The simplest model with manual cake removal by hand shovel or, for small models, lifting a bag by hand. This model is used mainly for small sizes (filter bag and filter cloth may be used).
ALFA/SB: The solids discharge is achieved by lifting the bag up (the most common system). An optional system can be used for “automatic” bag lifting.
ALFA/SB CA: The solids are discharged by a knife and evacuated via a pneumatic system (vacuum). The system is only useable with easy products that can be pneumatically transported and dedicated productions. The advantage is to avoid contact between operator and the product and between the product and the external environment.

Control Options

Complete PLC controls with touch screen interface
Switch between automatic, semiautomatic, and manual operation
Variable frequency drive (VFD) speed control
ATEX (Europe) electrical enclosures or NEC (North America)
Optional instrumentation integrated into the control system including oxygen monitoring, temperature, pressure, liquid feed flow, N2 purge flow, effluent particle detection and fluid clarity

Cleaning

The centrifuge should be cleaned at every change of product to avoid cross contamination between campaign productions. The fully automated centrifuge cleaning system is composed of 2 main stages: Washing Machine Effect and cleaning with spray balls, which can be alternated to achieve maximum cleaning and to optimize the consumption of the cleaning liquid.
C.I.P. (Clean-In-Place) avoids cross contamination at every change of production
Both options for the Washing Machine Effect cycle and spray balls are available

Machine Characteristics

Small footprint
Filter options:
- Polypropylene or other fabrics of various micron sizes
- Sintered metal screen for microfiltration (down to 2 microns)
Inertia base installation with visco dampers
Optional cake detector for automatic loading without operator intervention and cake thickness monitoring
System for dissolving the cake “in situ” to avoid typical solids discharge
For smaller machines, a glove box can be provided for high containment
Construction materials
- Parts in contact with the product: all stainless steels and special alloys are available, such as AISI 316L, AISI 904L, hastelloy, monel, alloy 59, 254 SMO, nickel, titanium, SAF 2205
- Surface coating option: Halar (ECTFE),
- Elastomers: antistatic and FDA certified, Teflon ETFE, and hard rubber

Technical Services

Field service and technical support available
Mechanical and electrical parts
Process control and maintenance manuals
Certifications and construction documentation
Mechanical and electrical upgrades

Standard Sizes and Technical Data

Centrifuge model: ALFA Unit	Basket Diameter mm	Basket Length mm	Filtering Surface m²	Cake Volume liters	Max Load kg	Max Speed RPM	G Factor xg	Centrifuge Weight kg
350/260	350	260	0.28	15	20	2800	1532	900
550/350	550	350	0.6	40	50	2550	2000	1200
630/400	630	400	0.8	63	80	1900	1250	1500
800/400	800	400	1.00	100	125	1500	1000	2900
1000/500	1000	500	1.57	200	250	1200	800	4000
1250/500	1250	500	1.96	315	400	1000	700	5300
1250/630	1250	630	2.47	400	500	1000	700	6000
1250/800	1250	800	3.14	500	625	1000	700	6500
1600/800	1600	800	4.02	800	1000	850	646	8000