Product Details

Product Description

Decanter centrifuges are used in industrial applications for the continuous separation of solids from liquids where the volume of solids is relatively high. The largest application in the UK is for dewatering sewage sludge containing around 1.5% to 3% solids in water. So the job of the centrifuge is to concentrate the amount of solids to just over 20% and remaining water, known as the Centrate, is as free from solid particles as possible. For some sludges a polymer (a chemical) is added to the process to encourage the solids to settle out of solution which aids the dewatering process. Providing the solids in a mixture of a light phase such as water and a heavier phase will settle in time under normal gravity, then using a centrifuge will accelerate the process. This is because normal gravity has a force of one G and a decanter centrifuge produces a centrifugal force of up to 4,000 G.

The centrifuge comprises a rotating assembly driven by a large electric motor mounted in a secure foundation frame, bolted to the ground through vibration dampers. The rotating assembly itself has two main components: the outer bowl and a screw conveyor. When the centrifuge is run up to operating speed the main drive motor turns the outer bowl at typically 3,000 r.p.m. A secondary motor is connected to the screw conveyor, the scroll, via cyclo-gearbox. The produces a differential speed between the outer bowl and the scroll of between 10 and 20 r.p.m. and has the effect of providing a conveying action inside the rotating assembly. When the centrifuge is up to speed the sludge, a mixture of solids and liquids, is pumped into centrifuge by an external pump through a feed tube into the feed chamber. The effect of centrifugal forces cause the solids to move towards the outside of the bowl and a separation of solids and liquids occurs. the conveying action of the scroll moves the solids towards the steep angle of the bowl where they are ejected through a number of discharge ports and fall into a collecting container under gravity. The liquid phase, runs over the weir plates at the other end of the rotating assembly and collected in a tank and pumped away. This is shown clearly in the video simulation which is available and can be opened in a new window alongside this explanation.

The feces water treatment centrifuge could deal with the material whose range of concentration is large, small size which is widely distributed. Solid particles are less than 0.5mm as rigid particles, and less than 10mm as non-rigid particles, the machine can treat effectively.

LW series decanter centrifuge is a horizontal centrifuge with continuous feeding and continuous discharging. The settling speed is determined by particle size, particle shape, difference in density between solids and liquids as well as their viscosity.

Screw Conveyor Drum

Feature

♦ Main parts such as the bowl and conveyor are made of corrosion-resistant stainless steel or duplex steel, offering high maximum bowl speed and high centrifugal force.

Tungsten Carbide Tiles

♦ Optional planetary gearbox and hydraulic gearbox, offering wide range of differential speed adjustment

Multiple safety protection: bowl speed and differential speed detection, over-vibration protection, motor overload and overheat protection, bearing temperature monitoring, conveyor torque protection and gas-tight explosion-proof protection.

Technical Parameters

Model	Bowl Dia (mm)	L/R Ratio	Bowl Speed (r/min)	G-force	Main Motor power (kw)	Weight (kg)	Dimension(mm) (LWH)
LW220x880	220	4	4800	2840	7.5-11	1000	18501200750
LW355x1460	355	4	4000	3100	22	2020	33659201060
LW450x1800	450	4	3500	3083	30-37	3500	420010901250
LW450X2050	450	4.5	3600	3260	30-37	37800	420010901250
LW530x2120	530	4	3200	3040	45-55	4200	488512301350
LW630x2300	630	3.65	2500	2205	75	8000	511014401750
LW720x2665	720	3.7	2000	1600	110	12000	536531601510

Structure drawing:

Separation Principle

1. Gravity Separation

On account of difference in density, the mixed liquid in the container, after a period of time, is gradually divided into 2 layers. The heavy phase particle of the mixed liquid deposits to the bottom of the container, while the light phase suspends to the upper surface. A rather distinctive dividing plane forms between the light phase and heavy phase. The separation speed is affected by the difference of density between the light phase and heavy phase that make up the mixed liquid. The larger the difference in density is, the faster the separation speed will be.

2. Centrifugal Separation

When the container filled with mixed liquid rotates at high speed around its own axis, due to the difference in density between the two phases making up the mixed liquid, they bear different centrifugal force. Under the action of a larger centrifugal force, the heavy phase in the mixed liquid quickly subsides on the inner wall of the drum, while the light phase slowly adhere close to the surface of heavy phase. The faster the container rotates, the larger the difference in centrifugal force borne by the light and heavy phases that make up the mixed liquid, and the faster the separation speed. When the container is equipped with such parts as feeding mainly comprised of such parts as drum, helical propeller, planet gear differential mechanism, pedestal, hood and lubricating system.