A practical centrifuge glossary.

Basket

The rotating container in a filtration centrifuge. A filter medium and supporting structure retain solids while allowing liquid to leave.

Batch operation

A repeated sequence of processing a defined quantity. Cycle time includes feed, separation, any washing, discharge and preparation for the next batch.

Bowl

The rotating body of a sedimentation centrifuge. Geometry and liquid level affect the separation and conveying regions.

CIP

Cleaning in place. Its effectiveness depends on the actual cleaning process, coverage, drainage and verification.

Cake

The retained solid bed after separation. Its moisture, permeability, strength and adhesion influence the complete process.

Cake heel

Residual material remaining after the main discharge. It may affect the next batch, recovery and cleaning.

Capture

The fraction of incoming solids recovered in the intended solids outlet, expressed on a stated basis.

Centrate

The liquid stream discharged from a sedimentation centrifuge. It can still contain suspended and dissolved material.

Centrifugal force

The rotating-frame description of the outward effect experienced by material. RCF expresses acceleration relative to gravity at a specified radius.

Clarification

Reduction of suspended matter in a liquid. It does not automatically remove dissolved substances.

Containment

The engineered control of process-material release. Required performance and verification depend on the material and project.

Decanter

A sedimentation centrifuge with a scroll that conveys settled solids out of a rotating bowl.

Differential speed

The speed difference between scroll and bowl or screen. It affects solids conveying and must be considered with load and torque.

Dry-solids basis

A reporting basis that excludes the water or other defined liquid fraction. Its analytical method must be stated.

Effective radius

The radius used for a particular centrifugal-acceleration calculation. It is not always equal to half the nominal machine diameter.

Feed envelope

The agreed range of feed composition, concentration, temperature, particle size and flow supporting the equipment design.

Filter cloth

A textile medium supporting filtration and cake formation. Material, weave, fit and cleaning behaviour matter.

Filtrate

Liquid that passes through a filter medium and cake. Early and late portions of a batch can have different qualities.

Filtration

Separation by passing liquid through a permeable medium while retaining suitable solids.

Flocculation

Aggregation of particles under suitable conditioning conditions. The response depends on the material and conditioning process.

G-force

Common shorthand for relative centrifugal force. It should be reported with the relevant radius and speed.

Inverting filter

A cloth-discharge concept in which the filter medium turns inside out to release retained cake.

Mother liquor

The liquid remaining with a crystalline or precipitated solid product before washing or further separation.

Particle-size distribution

A description of the spread of particle sizes, including fines and coarse fractions rather than only an average.

Peeler

A mechanism that removes cake from a basket using a controlled scraping action.

Permeability

How readily a fluid passes through a porous medium or cake under the relevant conditions.

Pond depth

The liquid level inside a decanter bowl, affecting the relationship between clarification and dewatering zones.

Pusher

A filtration centrifuge using reciprocating action to advance a suitable cake through its basket arrangement.

RCF

Relative centrifugal force: acceleration divided by gravitational acceleration. For r in cm and n in rpm, RCF = 1.118 × 10⁻⁵ × r × n².

Recovery

The amount of desired component obtained relative to the amount supplied, on a clearly defined mass or other basis.

SIP

Sterilization in place. It is a distinct requirement from cleaning and needs its own design and qualification basis.

Screen scroll

A filtration centrifuge combining a screen with differential-speed screw conveying of retained solids.

Sedimentation

Separation driven by relative phase densities and settling behaviour in the centrifugal field.

Siphon peeler

A peeler centrifuge using siphon or skimming liquid withdrawal to influence filtration conditions.

Solids loading

The mass of dry solids entering per unit time. It differs from hydraulic flow and can constrain equipment performance.

Three-phase separation

Separation of solids and two liquid phases where phase properties and the selected design permit it.

Turndown

The usable operating range below a stated design rate while meeting defined performance and operating conditions.

Viscosity

A fluid property describing resistance to flow. Its temperature dependence can strongly influence separation.

Wash ratio

A stated amount of wash liquid relative to a defined product, cake or other basis. Always specify the denominator.

Wet-basis moisture

Liquid mass divided by total wet material mass. Distinguish water-specific analysis from loss of all volatile components.