A tricanter centrifuge does something a two-phase decanter cannot: it takes a single feed stream and returns three of them — oil, water and solids — continuously, with no settling tank in between. That matters wherever two immiscible liquids and a solid phase arrive together: a wash stream that has picked up oil, a process stream that has to give up both water and cake, a waste stream where the liquid fraction is the valuable part. This guide explains how three-phase separation works inside the bowl, what the three phase decanter centrifuge separator published by Liaoyang Wintech is built from, what feed conditions it can handle, and how to tell whether your duty needs three phases or two.
What a tricanter centrifuge is
A tricanter — also written three-phase decanter, or three-phase horizontal screw decanter — is a solid-bowl, continuously operating settling centrifuge with one extra job compared with a standard decanter. A two-phase decanter separates a solid from a liquid. A tricanter separates a solid from two liquids that do not mix, by density: the heavier liquid, the lighter liquid and the solid each leave through their own path.
The machine is not a filter and does not use a filter cloth. Separation is by centrifugal force and density difference, which is why it tolerates the awkward feeds that blind a filter medium: oily sludges, fine suspended solids, streams whose composition moves during the shift.
How three-phase separation works inside the bowl
The working parts are a horizontal bowl rotating at high speed and a scroll conveyor inside it turning at a slightly different speed. Feed enters through the centre of the scroll, and from there the process runs continuously:
- Acceleration and settling. The high-speed rotation of the bowl forms a strong centrifugal field — many hundreds of times gravity — so the phases that would take hours to separate under gravity separate in seconds. The denser solid phase is thrown outward against the bowl wall; the liquid phases form rings inside it, the heavier liquid outside and the lighter liquid nearest the axis.
- Solids conveying. The scroll rotates in the same direction as the bowl but a little slower or faster, and its blades push the settled solids along the bowl wall towards the small end of the drum, where they are discharged at the cone.
- Heavy liquid discharge. The heavier liquid phase leaves through its own overflow path at the large (cylindrical) end of the drum.
- Light liquid discharge. The lighter liquid phase leaves through a second overflow path at the same end, at a different radius.
Where the two liquid phases actually separate
In a tricanter the boundary between the light and heavy liquid sits somewhere in the pond, and its position decides the purity of both streams. On a typical three-phase machine that boundary is set by adjustable weir plates or overflow discs at the cylindrical end: raising or lowering the heavy-phase weir moves the interface inwards or outwards. This is a mechanical setting made on the machine, not an electronic one, and it is the first thing to check when a tricanter starts carrying oil out with the water or water out with the oil. The typical tricanter design described here is standard industry practice; ask the supplier for the exact adjustment arrangement on the model you are quoted.
Why continuous operation matters
Because the machine feeds, separates and discharges at full speed, it runs 24 hours a day with no fill–spin–unload cycle. On a line that never stops — a refinery wash stream, a rendering or food process, a chemical plant running three shifts — that removes the buffer tanks and the operator attention that a batch centrifuge needs. The published description of the Wintech machine puts it plainly: the strong centrifugal field formed by the rotating bowl makes continuous dewatering possible around the clock.
What is inside a three-phase decanter
The main machine published on the product page consists of: a column-cone bowl, a spiral stoker (scroll conveyor), the differential system, the bearing seat, the base, the cover, a main motor, a vice (back-drive) motor and the electrical control chamber. Each item earns its place:
- Column-cone bowl. The cylindrical section is where settling happens; the cone is the dewatering and discharge zone.
- Spiral stoker. The conveyor that moves solids out of the pond. Its geometry — pitch, blade form and how it is hardened — is the single biggest factor in how well a decanter handles a given solid.
- Differential system. The gearbox that creates and holds the small speed difference between bowl and scroll while transmitting the scroll torque.
- Two motors and the control chamber. A main drive for the bowl and a back drive for the scroll, which together let the differential speed be set and, on better installations, held at constant torque when the feed solids load changes.
Feed conditions a decanter can handle
The published suitability window for this machine is a suspension with solid particle size greater than 0.005 mm and a concentration range of 2–40%. It also states that the machine can separate solids across a 0.005–2 mm size range and will keep separating normally when the particle size is uneven — which is the normal condition in a real process stream, not a laboratory one.
Read those two figures as the frame of the selection rather than the whole story. Particle size sets whether the solid will settle fast enough inside the bowl; concentration sets the solids load per hour and therefore the differential-speed setting and the scroll torque you need. A fine but dilute feed and a coarse but thick one are different problems for the same machine, so quote both to the supplier.
Wear protection: where the money is spent
A decanter’s wearing parts are the scroll flights and the discharge ports, and this machine’s published specification addresses both: the spiral blades are hardfaced by surfacing welding and spray welding of tungsten carbide, and by bonded ceramic sheets; the discharge port is fitted with ceramic or hard-alloy inserts. That combination is what makes a machine suitable for abrasive mineral, sand-bearing or crystalline solids rather than only for soft sludge.
Two practical points follow. First, wear protection is not a fixed specification — the right choice depends on your solid’s abrasiveness, and it is legitimate to ask for a harder or a cheaper surface based on your own wear history. Second, the flights and the ports are replaceable items; when comparing offers, compare the price of a wear set and the time to change it, not only the price of the machine.
Two-phase or three-phase: how to decide
Three phases only pay for themselves when there really are three phases with somewhere to go. Three questions decide it:
- Is there a second immiscible liquid? If the feed holds one liquid and a solid, a two-phase decanter is simpler, cheaper and easier to tune — see the two phase decanter centrifuge separator.
- Does one of the liquids have to be recovered clean? The value of the recovered oil, solvent or product stream is what funds the tricanter.
- Is the composition stable enough? A three-phase machine has one more interface to hold. If the oil content swings wildly, expect more operator attention on the weir settings — or accept a two-stage route instead.
| What is in the feed | Machine that fits the duty |
|---|---|
| Solid + one liquid | Two-phase decanter |
| Solid + two immiscible liquids, one of them worth recovering | Tricanter (three-phase decanter) |
| Very fine solids, the liquid is the product | Disc or tubular separator |
| Coarse or crystalline solid that is the product | Filter centrifuge or filter press |
The comparison in more depth — separation principles, design differences and selection rules — is in two-phase vs three-phase decanter centrifuge, and the general working principle of the decanter family is covered in introducing our decanter centrifuge.
Where tricanters are used
The published application spread for this machine is chemical, light industry, pharmaceutical, food and environmental protection. Across those industries, three-phase duty typically appears wherever an oil or solvent phase has to be separated from water and solids at the same time — oily process water and slop streams, food and rendering process liquids, and industrial wash streams in which a recoverable liquid phase is carried with the solids.
Two neighbouring families are worth knowing, because the boundary between them and a tricanter is exactly where selection mistakes happen. When the solid is the product and the duty is really filtration, the SS series dewatering filter centrifuge, the plate basket centrifuge separator and the plate filter centrifuge separator work on the filtration principle instead of settling. When the solids are extremely fine and the liquid is the valuable phase, clarifying separators do the job better: a disc centrifuge separator for high-G clarification of a low-solids liquid, or a tubular centrifuge separator for very fine, low-concentration suspensions. For a sludge that is mostly water and has to be dewatered to a solid cake, a plate and frame filter press or a screw press such as the animal manure treatment screw press machine can be the better economics.
Operating and maintenance notes
Three characteristics of the published machine matter to whoever runs it. It is built for automatic, continuous, long-period operation with closed construction, so the process stream stays inside the machine and the working area stays clean. It is compact for its capacity, which keeps the foundation and floor space small relative to the throughput — useful where an existing line is being upgraded rather than built. And it supports DCS control, which means the machine can be tied into the plant’s control system rather than run as a stand-alone unit with its own panel.
Maintenance centres on three things: the wear set inside the bowl, the differential gearbox oil, and the speed settings that follow every change in feed. Log the differential speed and torque you actually see, and the next machine can be sized from data instead of a table.
FAQ
What does a tricanter centrifuge separate?
Three streams from one feed: a solid phase, a heavy liquid phase and a light liquid phase. In process terms that usually means solids plus oil (or solvent) plus water, separated continuously and discharged through separate outlets.
Is a tricanter the same as a three-phase decanter?
Yes. “Tricanter” is the common industry name for a three-phase decanter centrifuge — a solid-bowl scroll centrifuge arranged to take off two liquid phases as well as the solids. Machine builders differ in how the two liquid phases are taken off, so the weir or overflow arrangement is worth confirming with each supplier.
What feed concentration can a decanter handle?
The published figure for this machine is a concentration range of 2–40% and a solid particle size greater than 0.005 mm, with separation across a 0.005–2 mm range and tolerance of uneven particle size. Your own stream should be tested for settling behaviour before a model is fixed.
Does a tricanter need filter cloth or chemicals?
No filter cloth: separation is by centrifugal settling, with the scroll handling solids discharge. Polymer or flocculant is not needed for density separation of the kind a tricanter performs, though it can still be used upstream if the process already calls for it.
How do I get the dimensional parameters for the machine?
Ask for the current parameter sheet for the model being quoted, and state the three numbers that matter to the selection: dry solids per hour, the composition of the feed by weight, and the target quality of each of the three discharged streams.