They are used in many processes, primarily in the bulk chemicals, fine chemicals, and food industries.
Peeler centrifuge HZ 125/3.2
Feeding and discharge
By utilizing the rotary siphon feature, an original ANDRITZ Separation GmbH development, the overall performance of the peeler centrifuge can be improved considerably. Substantial advantages include:
Creating a vacuum beneath the filter cloth increases the filtration pressure and boosts the filtration rate.
The filtration rate can be adjusted to prolong the contact time between wash liquid and solids to produce a purer cake.
Regeneration of the residual heel is achieved by means of backwashing through the filter medium.
As a result of backwashing and throttling of the filtration rate, the siphon feature enables feeding into a liquid pool to achieve uniform distribution of solids without vibration, even with fast-filtering products.
Bulk chemicals, petrochemical intermediates, fertilizers, chlorides, sulfates, calcium compounds, sodium compounds, fine chemicals, aluminum fluoride, amino acids, bleaching agents, surfactants, herbicides, pesticides, catalysts, dyestuffs, plastics/related products, ABS, resins, melamine, PE, PP, antioxidant agents pharmaceuticals/related products, APIs, vitamins, salicylic acid, citric acid, ascorbic acid, calcium citrate, antibiotics
Native and modified starches, artificial sweeteners, vanillin, caffeine
| Average particle size | 2 - 500 μm |
| Feed solids concentration | > 3 % by wt. |
| Solids throughput | up to 15 t/h |
| Basket diameter | 250 – 2,000 mm |
| Basket volume | 2.5 – 1,900.0 l |
Krauss-Maffei peeler centrifuge HZ - Operational video
The horizontal rotor assembly is cantilever-mounted and, depending on the application, can be provided with a conventional filtration basket or a specially designed rotary siphon basket. A fully opening housing door provides access to the basket and all process components for maintenance. Adding variable speed drives and custom-tailored controls and instrumentation enables the peeler centrifuge to be optimally adapted to a multitude of processing requirements for peak performance.
Krauss-Maffei peeler centrifuges are equipped with various basket designs. The versions most frequently applied are the conventional filtration basket and the rotary siphon basket, an original ANDRITZ Separation GmbH development.
The filtration basket has a fabricated/welded or cast design and a filtration basket with a cylindrical shell and filtrate bores through which the filtrate is spun out into the filtrate housing after passing through the filter medium.
Unlike the conventional perforated basket, the rotary siphon basket has a solid cylindrical shell with filtrate bores arranged radially at the rear end of the basket, where they are connected to a siphon-shaped chamber. Once it has penetrated the filter cake and the filter medium, the filtrate is redirected through axial channels beneath filter medium support segments into the siphon chamber, where a pivoting skimmer pipe extracts it from the centrifuge under positive pressure. The radial distance between the filter medium and the liquid level in the siphon chamber increases the driving force and thus, also the filtration rate.
After frequent cycles, the residual heel may have compacted with enough fine solids to make it impermeable, resulting in poor filtration performance. When this occurs, the heel can be regenerated (by backwashing in siphon peeler centrifuges) or removed pneumatically or hydraulically (in peeler centrifuges with filtration baskets).
By blowing either compressed air or nitrogen against the heel through special flat-jet nozzles mounted on a pivoting and oscillating manifold inside the basket, the heel cake is broken up into pieces and discharged by the peeling device.
Using the feed distributor, a large quantity of rinse liquid is fed to the basket for a short period of time. The resulting shear forces create sufficient turbulence to lift the heel off the filter medium. The rinse liquid with the dispersed heel solids is discharged from the basket by the peeling device. This step requires diverting the liquid to outside the centrifuge away from the normal dry product discharge. The rinse liquid can be recycled to the main process or divided into heel solids and liquid in a separate process step. In both procedures, the heel is removed at low basket speeds to avoid tearing the filter medium. Hydraulic heel removal has the added advantage of simultaneously cleaning the interior of the centrifuge. The most suitable removal procedure will depend upon the specific application.
Example HZ 200 for starch, highest capacity up to 15 tph
Outline sketch of the Krauss-Maffei peeler centrifuge HZ
