GELEN screw classifiers and sand screws wash, classify and dewater sand in a single machine. Silt and clay leave with the overflow water while the spiral carries clean sand up the incline, draining as it goes, and discharges a product that can go straight to the stockpile. Two series cover compact plants and high-tonnage lines: HY screw classifiers and GFW fine material washers, each in single and twin spiral designs.
Wash, classify and dewater: the tank washes the sand, the overflow weir takes away silt and clay, and the rising spiral drains the product — no separate dewatering stage is needed for most concrete and asphalt sand.
Single or twin spiral: both series include single and twin spiral machines, so more sand can be handled without moving to a longer machine.
Two capacity classes: compact HY classifiers suit smaller sand lines and plants with limited water; GFW washers handle up to 725 t/h in long, large-diameter spirals.
Slow and simple: the spiral turns at low speed (5–21 rpm on the GFW series), which keeps wear, noise and energy use low and maintenance straightforward.
The HY series is GELEN's compact screw classifier. Each machine is an inclined tank with a spiral shaft running its full length. Sand slurry is fed into the lower pool, where the water carries silt, clay and very fine particles over the overflow weir. The heavier sand settles onto the spiral, which conveys it up the incline and out of the water. On the dry part of the incline the sand drains before it drops from the discharge chute.
HY classifiers are built in single spiral (HY880, HY660) and twin spiral (HY1100-2, HY880-2, HY660-2, HY550-2) versions. The model name gives the spiral: HY880 has an Ø800 mm spiral 8,000 mm long. Outputs run from 30 t/h to 160 t/h, quoted for 0–3 mm and 0–7 mm sand products, with drive powers from 5.5 kW to 2 × 11 kW.
A typical HY installation sits under a wet screen or after a VSI crusher, taking the sand fraction and turning it into a washed, drained product ready for concrete and asphalt specifications.
| SPIRAL Ø x LENGTH mm | OUTPUT 0–3 mm t/h | OUTPUT 0–7 mm t/h | PowerkW | Weightkg | ||
|---|---|---|---|---|---|---|
| Single spiral | HY880 | Ø800 x 8000 | 75 | 100 | 11 | 4,500 |
| Single spiral | HY660 | Ø600 x 6000 | 30 | 45 | 5.5 | 2,500 |
| Twin spiral | HY1100-2 | Ø1000 x 10000 - 2 | 110 | 160 | 2 x 11 | 6,500 |
| Twin spiral | HY880-2 | Ø800 x 8000 - 2 | 110 | 160 | 2 x 11 | 6,500 |
| Twin spiral | HY660-2 | Ø600 x 6000 - 2 | 55 | 85 | 2 x 5.5 | 3,500 |
| Twin spiral | HY550-2 | Ø500 x 5000 - 2 | 40 | 60 | 2 x 4 | 2,700 |
Outputs are given for 0–3 mm and 0–7 mm sand products. Actual capacity depends on the feed gradation, the fines content and the water volume.
The GFW series is the high-capacity sand screw. Long, large-diameter spirals give the sand more time in the pool and on the drainage incline, so GFW washers remove silt, clay and ultra-fine contaminants from specification sands at tonnages up to 725 t/h.
Four spiral sizes, from 915 × 7,620 mm to 1,676 × 10,670 mm, are each built as a single spiral (S) or twin spiral (T) machine. Heavy-duty gear reducers drive the spirals at 5–21 rpm depending on size, and water demand is published for every model so the water circuit can be sized with the washer.
GFW washers are the choice when a plant produces large volumes of concrete or asphalt sand, or when a sand product must be cleaned to a tighter fines limit than a compact classifier allows.
| Spiral Sizemm | Feed Sizemm | Max Capacityt/h | Est. Water Requiredm³/h | Power RequiredkW | Speedrpm | |
|---|---|---|---|---|---|---|
| GFW3625S | 915 x 7620 | 10 | 22–90 | 163.5 | 11 | 10–21 |
| GFW4432S | 1120 x 9700 | 10 | 35–160 | 391 | 18.5 | 8–17 |
| GFW5434S | 1370 x 10010 | 10 | 60–250 | 475.1 | 30 | 7–14 |
| GFW6636S | 1676 x 10670 | 10 | 90–360 | 589 | 45 | 5–11 |
| GFW3625T | 915 x 7620 | 10 | 45–180 | 284.1 | 2 x 11 | 10–21 |
| GFW4432T | 1120 x 9700 | 10 | 70–315 | 635 | 2 x 18.5 | 8–17 |
| GFW5434T | 1370 x 10010 | 10 | 125–495 | 840.3 | 2 x 30 | 7–14 |
| GFW6636T | 1676 x 10670 | 10 | 180–725 | 993.1 | 2 x 45 | 5–11 |
S = single spiral, T = twin spiral. Maximum feed size 10 mm. Water requirement is the estimated volume for the maximum capacity.
A twin HY installation at a quarry. Five things worth naming.
The flight lifts settled sand up the incline while the water runs back down past it. Its leading edge is the wear surface: a worn edge costs capacity and dewatering at the same time, which is why the flights are on the inspection schedule.
Geared drive at the top end, above the water line. Neither the motor nor the reducer ever sits in the slurry.
Sand settles here while the silt stays in suspension. The balance between water volume, feed rate and spiral speed is what decides where the fines are cut.
Silt and wash water leave over this edge. What goes over it and what stays behind is decided right here, which is why the pool conditions at the weir matter as much as the water volume going in.
Sealed and greased for life, running below the slurry line. This is the hard part of the machine, and the seal is where it is won or lost.
GELEN screw classifiers cover sand washing duties from 22 t/h to 725 t/h. The HY series offers spirals from Ø500 mm to Ø1,000 mm in 5 to 10 m lengths; the GFW series offers spirals from 915 mm to 1,676 mm in 7.6 to 10.7 m lengths. Both series include single and twin spiral machines. Tell us your feed gradation, fines content and target product, and GELEN engineering will size the classifier and its water circuit for your plant.
Every screw classifier is built to its duty. Send those numbers and an engineer comes back with a size, a drive and what it will do in your circuit.
Size one for meA screw classifier combines three processes in one tank. The balance between water volume, feed rate and spiral speed decides where the fines are cut and how dry the product leaves.
Sand slurry from a wet screen, sump or crusher enters the pool at the lower end of the inclined tank.
Water flows toward the overflow weir, carrying silt, clay and ultra-fine particles out of the tank.
The heavier sand settles onto the rotating spiral, which lifts it up the incline and out of the pool.
Above the waterline the sand drains as it travels, then drops from the chute onto a stockpile conveyor.
GELEN screw classifiers work in aggregate, mining and recycling plants wherever sand must leave clean, graded and drained.
Washing natural and crushed sand to remove the silt and clay that weaken concrete and asphalt mixes, producing 0–3 mm and 0–7 mm products.
Cleaning the fines-rich sand a VSI crusher produces, so manufactured sand meets the fines limits of concrete specifications.
Washing and dewatering sand fractions in mineral processing and industrial sand plants, where a consistent product is sold on specification.
Washing the sand fraction from construction and demolition waste, removing soil and light contaminants so recycled sand can be reused.
The engineering choices behind GELEN screw classifiers and sand screws.
A single tank and spiral replace separate washing, classifying and dewatering machines for most sand products, keeping plant layouts short.
Both series include single and twin spiral machines, so capacity can be matched to the plant without moving to a longer machine.
HY classifiers serve compact sand lines from 30 t/h; GFW washers carry high-tonnage specification sand to 725 t/h.
Spirals turn slowly — 5 to 21 rpm on the GFW series — so abrasion, power demand and maintenance stay low on hard, sharp sands.
The GFW table lists the water each model needs, so pumps, pipework and water recycling can be designed together with the washer.
GELEN designs the screens, crushers, conveyors and washing equipment around the classifier, so the whole sand line is sized as one system.
In most plants the screw classifier takes the sand fraction after wet screening or a VSI crusher and delivers the finished sand product. Where very fine sand must be recovered from the overflow water, a sand washing plant with hydrocyclones follows it.
Every circuit is different. Send us yours and we will say where a screw classifier fits and what it changes downstream.
Check my circuitThree machines wash material in a sand and gravel plant. They solve different problems and often work together.
| Screw Classifier | Sand Washing Plant (GSP) | Log Washer | |
|---|---|---|---|
| Main job | Wash, classify and dewater sand | Recover fine sand from slurry and dewater it | Scrub clay and conglomerates off coarse material |
| Material | Sand (GFW feed up to 10 mm) | Sand in slurry | Gravel and crushed stone with clay |
| Fine sand recovery | Fines below the cut leave with the overflow | Hydrocyclones recover fine sand the overflow would lose | Not a sand machine |
| Product | Drained sand | Low-moisture sand from a dewatering screen | Scrubbed coarse material to a rinsing screen |
| Typical position | After wet screening or a VSI crusher | On screw classifier overflow, or instead of a classifier | Before wet screening |
See sand washing plants and log washers.
Not sure which one? Send us the duty and an engineer will say which, and what you would give up by choosing the other.
Which one fits?
Technical guides and industry organisations for sand and aggregate producers.
A screw classifier is an inclined tank with a rotating spiral (screw) running its length. Sand slurry is fed into the pool at the lower end. Water flows toward the overflow weir and carries silt, clay and very fine particles out of the tank, while the heavier sand settles onto the spiral.
The spiral conveys the settled sand up the incline and out of the water. On the part of the incline above the waterline the sand drains, so it leaves the discharge chute as a washed, classified and dewatered product. GELEN builds screw classifiers in the HY series (30–160 t/h) and the larger GFW fine material washer series (22–725 t/h).
The terms describe the same kind of machine. "Screw classifier" stresses the classification at the overflow weir; "sand screw" or "fine material washer" stresses the washing of the sand. Both use an inclined tank and a spiral to wash, classify and dewater sand.
At GELEN the HY series is the compact screw classifier, and the GFW series is the high-capacity fine material washer with longer, larger-diameter spirals for specification sand at high tonnages.
A twin spiral machine has two spirals in one tank and handles considerably more sand than a single spiral of the same size. In the HY series, for example, the single spiral HY880 is rated at 75 t/h of 0–3 mm sand, while the twin spiral HY880-2 is rated at 110 t/h; on the GFW series the twin spiral (T) models carry about twice the tonnage of the single spiral (S) models.
Choose a single spiral when the sand tonnage is modest or space across the plant is limited, and a twin spiral when the tonnage is high or future expansion is planned.
The cut between the sand that is kept and the fines that are washed out depends on the water volume, the feed rate and the pool conditions at the overflow weir. More water or a faster upward flow carries coarser particles out; less water keeps more fine sand in the product.
In practice operators balance the water volume against the feed so that silt and clay leave with the overflow but saleable fine sand stays on the spiral. If valuable fine sand is being lost, a sand washing plant with hydrocyclones can recover it from the overflow.
A screw classifier is simple, slow-moving and well suited to washing and dewatering concrete and asphalt sand where a small loss of the finest particles is acceptable.
A sand washing plant with hydrocyclones and a dewatering screen, such as the GELEN GSP series, recovers more of the fine sand and produces a drier product, at the cost of a pump, cyclones and a vibrating screen. Many plants use both: the screw classifier produces the main sand, and a sand washing plant recovers fine sand from its overflow.
Water demand depends on the machine size, the tonnage and how much silt and clay must be removed. For the GELEN GFW series the estimated water requirement at maximum capacity ranges from about 164 m³/h on the GFW3625S to about 993 m³/h on the GFW6636T; every model's figure is listed in the specification table.
The water circuit — pumps, pipework, settling ponds or water recycling — should be designed together with the classifier.
The HY series covers 30 to 160 t/h, quoted for 0–3 mm and 0–7 mm sand products, from the single spiral HY660 to the twin spiral HY1100-2 and HY880-2. The GFW series covers 22 to 725 t/h, from the single spiral GFW3625S to the twin spiral GFW6636T.
Actual capacity depends on feed gradation, fines content and water volume, so GELEN sizes the machine from your material data.
Yes. VSI crushers produce well-shaped sand but often with more fines than concrete specifications allow. A screw classifier after the VSI washes out the excess fines at the overflow and delivers a drained manufactured sand, which is one of the most common uses of the HY and GFW series.
Send your material, your capacity and the product sizes you need. An engineer answers, not a form.