Classification of decanter centrifuges

Decanter centrifuge (horizontal screw discharge centrifuge) has a variety of classifications.

5. It can be divided into: horizontal screw biological centrifuge, horizontal screw pharmaceutical centrifuge, horizontal screw chemical centrifuge, horizontal screw food centrifuge, horizontal screw starch centrifuge, horizontal screw protein centrifuge, horizontal screw dairy centrifuge, horizontal screw milk fat centrifuge, horizontal screw juice centrifuge, horizontal screw oil centrifuge, horizontal screw oil field centrifuge, horizontal screw rare earth centrifuge, horizontal screw mineral pulp centrifuge, horizontal screw sewage centrifuge, horizontal screw wastewater centrifuge Horizontal screw sludge centrifuge, horizontal screw slurry centrifuge, horizontal screw Coal Slime Centrifuge, horizontal screw coal tar centrifuge, horizontal screw dewatering centrifuge, horizontal screw concentration centrifuge, horizontal screw clarification centrifuge and horizontal screw treatment centrifuge, etc.

Decanter centrifuge is mainly composed of drum, screw, differential system, liquid level baffle, driving system and control system. Horizontal screw centrifuges use the density difference between solid and liquid phases to accelerate the sedimentation rate of solid particles under the action of centrifugal force to realize solid-liquid separation. The specific separation process is that the sludge and flocculant liquid are sent to the mixing chamber in the drum through the inlet pipe for mixed flocculation (if the sludge is added in front of the pump or in the pipeline after the pump, the flocculation reaction has been carried out in advance). Due to the high-speed rotation and friction resistance of the rotor (screw and drum), the sludge is accelerated inside the rotor and forms a cylindrical liquid ring layer (liquid ring area). Under the action of centrifugal force, The solid particles with large specific gravity settle to the inner wall of the drum to form a mud layer (solid ring layer), and then use the relative speed difference between the screw and the drum to push the solid phase to the cone end of the drum. After pushing out the liquid level (shore area or drying area), the sludge can be dehydrated and dried, and discharged to the slag discharge port. The supernatant is discharged from the big end of the drum to realize solid-liquid separation.

For the use effect of horizontal screw centrifuge, the influence of its mechanical part is divided into adjustable factors and non adjustable factors. Now it is explained separately. First, understand its action principle, and you can effectively control it in use.

Non adjustable mechanical factors

The larger the diameter of the drum, the longer the effective length, the larger the effective settlement area, the greater the processing capacity, and the longer the residence time of materials in the drum. At the same speed, the greater the separation factor and the better the separation effect. However, due to the limitation of materials, the drum diameter of centrifuge cannot be increased indefinitely, because with the increase of diameter, the allowable maximum speed will decrease with the decrease of material firmness, so the centrifugal force will decrease accordingly. Generally, the diameter of the drum is between 200 ~ 1000mm, and the length diameter ratio is between 3 ~ 4. The development of horizontal screw centrifuges now tends to have a trend of high speed and large aspect ratio. This kind of equipment is more suitable for the treatment of low concentration sludge, and the degree of sludge biscuit is better.

In addition, under the condition of the same processing capacity, the centrifuge with large drum diameter can operate at a lower differential speed. The reason is that the spiral slag conveying capacity of large drum diameter is large. In order to achieve the same slag conveying capacity, the centrifuge with small drum diameter must be realized by increasing the differential speed.

The process area of atmospheric pressure horizontal screw centrifuge is directly connected with the atmosphere. According to the purpose, it can be non dewatering horizontal screw centrifuge and clarification horizontal screw centrifuge.

The so-called easily separated material refers to the suspension containing solid particles with fast natural sedimentation speed and easy slag pushing. Restrained by Stoke's law, the solid phase in the suspension belongs to medium and coarse particles, the gravity difference between solid and liquid phase is relatively large, and the viscosity of liquid phase is relatively small. Such materials include a wide range, such as flotation concentrate and tailings of coal preparation plant, polyvinylethylene, polypropylene, polyvinyl alcohol, starch, mixed liquid of edible oil residue, etc.

The drum is conical and cylindrical conical. Its characteristic is that the length and diameter of the drum are relatively small, generally 1-2, mostly about 1.5. The suspension containing medium and coarse particles with high separation concentration requires the centrifuge to have higher sediment carrying capacity and slag conveying capacity, which is generally larger in diameter than the horizontal screw centrifuge for clarification. Since the materials are easy to separate, it is unnecessary to improve the aspect ratio. The diameter of the drum is longer and the cost is lower than that of the drum. The twist cone is relatively large, and the half angle cone angle is between 10-18 degrees. Large cone angle and high dehydration and separation factors are conducive to the dehydration of sediment. It will not be difficult to transport slag for particles that are medium, coarse and easy to push. For example, for the horizontal screw centrifuge used in flotation coal mine, the half angle cone is generally 15-18 degrees. Further increasing the cone angle will increase consumption, aggravate the wear of spiral blades, and even fail to push out slag.