Hydraulic classifier is a kind of particle sizeclassificationEquipment.With highefficiency, Lowenergy consumption, NonenoiseAnd other advantages.It is specialized in mineral classificationequipmentSystem.Its design idea originated in 1988Ahern University of Technology, GermanySeveral mineral processing projects of Aachen University of TechnologydoctorR&D byGermanyThe application of all mineral was obtained in 1991 and 1992 respectivelyGermanyandEuropePatents.
Hydraulic classifier is a kind of particle sizeclassificationEquipment.With highefficiency, Lowenergy consumption, NonenoiseAnd other advantages.It is specialized in mineral classificationequipmentSystem.Its design idea originated in 1988Ahern University of Technology, GermanySeveral mineral processing projects of Aachen University of TechnologydoctorR&D byGermanyThe application of all mineral was obtained in 1991 and 1992 respectivelyGermanyandEuropePatents.
Structure and principle
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Structure of hydraulic classifier
1. Pyramid box: the ore particles are roughly classified in the horizontal flow, and the pulp concentration is relatively thin.
2. Mixing chamber: classification is carried out under the condition of high pulp concentration due to coarse particle sedimentation.
3. Classification room: re classification is carried out in the rising water flow, and the classification can be observed through the glass window.
4. Vortex box: feed high-pressure rising water.
5. Lifting rod: there is a tapered plug at the lower end, and the size of the gap (the size of the graded mineral particles) is controlled by the screw rod.
6. Grit box (buffer box): to prevent the grading process from being damaged by torrents when the grit is discharged, so as to ensure normal continuous ore discharge.
detailed description
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Basics of Hydraulic ClassifierstructurepresentcircularThe main body consists of upper cylinder and lower cylinderconeCombined.High efficiency classification is completed by fluidized bed and rising water technology in the coarse particle classification room in the middle and the circular fine particle classification room around it.The slurry passes through a special pipe from the middle of the coarse particle classification roomverticalTo the distribution tray at the bottom of the coarse grading chamber.The rising water enters through the circular gap between the distribution plate and the coarse particle classification indoor wallCoarse particle classification roomA turbulent zone is formed at the lower part of the coarse particle classification room to realize coarse particle classification.Coarse minerals are settled according to the process requirements, and enter into the coarse grain discharge opening located in the middle of the bottom of the coarse grain classification room through the above circular gap.Fine minerals enter by overflowannularOfFine particle classification room。
Fine particle classification room uses fluidized bed technology to classify fine and ultra fine minerals.The rising water is evenly distributed at the bottom of the whole fine particle classification chamber through the specially made screen surface installed at the bottom of the fine particle classification chamber, so as to ensure the formation of a uniform and stable laminar fluidized bed and achieve accurate classification.Ultra fine minerals enter the annular overflow tank surrounding the fine grading chamber and are discharged.Fine minerals will settle to the bottom of the fine grading chamber, and after being distributed in a ring shape along the screen surfacevalveDrain away.
The opening, closing and discharging speed of all discharge valves in coarse and fine grading chambers are controlled and adjusted through online measurement of pulp density.Under the condition that the fluid load on site is known, the particle size of coarse, fine and ultra fine products (that is, grit setting in coarse grading chamber, grit setting in fine grading chamber and final overflow of equipment) can be adjusted by changing the height of fluidized bed and rising water volume.In addition, the concentration and flow distribution of each classification product can also be adjusted within a certain range according to the process needs.
According to the feed particle size, mineral specific gravity, slurry concentration and other parameters, different and adjustable rising water volume is used, and the screen surface at the bottom of the fine particle classification chamber with different structures is selected to adjust the pressure difference between the screen surface and the top, which can ensure the uniform fluidization and accurate classification of mineral particles.
Suggestions for improvement
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The hydraulic grader has been continuously improved and perfected in many years of application practice in the silica sand beneficiation industry. The automatic control system level, classification efficiency, noise control and other aspects of the hydraulic grader have been optimized to a certain extent.
(1) Improvement of control system.
The first hydraulic grader developed by Huahai Company of Bengbu Glass Design Institute in China usedPneumatic controlThe system realizes automatic opening and closing of ore discharge valve through air compressor, pneumatic die head, pressure detection tube, pneumatic instrument and other devices, but production practice shows that the system occupies a large area (air compressor room needs to be configured separately), has serious noise pollution, the pneumatic die head is bulky and complex to repair, and the gas transmission pipeline is difficult to strictly ensure no leakage. To overcome this series of problems,The electric control system came into being at the historic moment. According to statistics, all hydraulic graders have achieved electric control, and the application in production is in good condition, which has been unanimously recognized by silica sand production enterprises.
(2) Improvement of turbulence plate.
The hydraulic grader has strict requirements for the stability and uniformity of the rising water flow. Therefore, a pressure stabilizing water tank and a turbulent plate are specially designed. Many round holes are evenly distributed on the turbulent plate, and the aperture is generally 5-8mm.The turbulence plate of the earlier hydraulic classifier used the method of opening holes in ordinary steel plates. This turbulence plate had a good separation effect at the beginning of the equipment use stage, but with the abrasion of quartz sand on the turbulence plate.At this time, the grading effect will become worse due to the uneven distribution of rising water, and even there may be water inrush or scarring at local locations, and the overflow surface will not be stable;At the same time, coarse sand will accumulate in the pressure stabilizing water tank due to continuous sand leakage, which will also affect the sorting effect when there is a large amount of coarse sand. Therefore, the turbulence plate can be improved for wear resistance and sand leakage prevention. Now the effective method is to install a special rubber nozzle on the rising water hole of the turbulence plate. The device is designed to be in a forward flow and reverse closed structure,The material used is wear-resistant rubber. The production practice has proved that it can effectively control the sand leakage and the abrasion of the rising water hole, thus ensuring the continuous good grading effect of the classifier.This technology has been declared a national patent[1]。
