Dewatering screen, the main role is to dewatering, desliming, demixing, can be used for sand and gravel plant washing sand, coal plant coal slurry recovery, mineral processing plant tailings dry discharge, etc., so it is also known as sand and gravel dewatering screen, mining dewatering screen, coal slurry dewatering screen, tailings dewatering screen, high-frequency dewatering screen and so on. Although the same belongs to the dewatering equipment, but the role of different materials, the structure of the dewatering screen is still different, such as washed sand production line sand dewatering screen and tailings dewatering screen commonly used in mineral processing plant is a different device.
Dewatering screen working principle
Dewatering sieve adopts double electrode self-synchronization technology, universal eccentric block, adjustable amplitude vibrator. It is mainly composed of screen box, exciter, supporting system and motor. Through the tape coupling respectively drive two mutually unrelated vibrators for synchronous reverse operation, the centrifugal force generated by the two sets of eccentric mass along the vibration direction of the superposition of the centrifugal force, reverse centrifugal offset, thus forming a single vibration along the vibration direction of the excitation, so that the screen box to do for reciprocating linear motion.
The working principle of high-frequency dewatering vibrating screen is to use high-frequency vibration to destroy the surface tension of the slurry, and fine-grained materials will be high-speed oscillation on the screen surface, thus accelerating the precipitation of the large density minerals, increasing the probability of less than the separation of particle size of the material and sieve hole contact, double vibration motors or flange-type vibration exciters, two motors outside the trailing to do the opposite direction of the self-synchronous rotation, so that the sieve body along the straight line direction of the cyclic reciprocating motion, fine-grained materials can quickly pass through the screen hole to be screened out to achieve the purpose of screening and dewatering. Fine-grained materials can be quickly screened out through the sieve holes, in order to achieve the purpose of screening and dewatering.
Due to the high frequency sieve adopts high frequency, on the one hand, it destroys the tension on the surface of the slurry and the high-speed oscillation of fine-grained materials on the sieve surface, accelerates the precipitation of useful minerals with high density, and increases the probability of contact between the materials smaller than the separation granularity and the sieve holes. Thus creating a better separation conditions, so that less than the separation size of the material, especially the specific grains and slurry through the sieve holes together to become the product under the screen.
Dewatering sieve performance advantages
1、The dewatering screen mesh material is made of polyurethane, impact resistance, low temperature resistance, abrasion resistance, chemical corrosion resistance, self-lubrication, absorption of impact energy, impact resistance is a high value in all plastics, and abrasion resistance is better than polytetrafluoroethylene, nylon, carbon steel and other materials.
2、New dewatering screen has two functions of dewatering and recycling, simple structure, easy to maintain and operate, saving investment costs and floor space.
3、The vibration motor of the dewatering screen is easy to replace, and the rubber spring at the base is used to dampen the vibration, so that the amplitude is not big, and the slow vibration can be dewatered cleanly.
4、Dewatering sieve can be customized according to the output and water content, the side plate of the body has a reinforcing plate, the bottom is equipped with support, the bottom of the horizontal strips, the outlet plus a triangular steel plate support, plate thickness, the sieve holes can be adjusted according to the need for the size, to meet the individualized production.
5、For products with low mud content, you can also use the dewatering screen directly, without the need to use the sand washing machine, which saves the customer’s cost and can achieve the same effect.
Workflow of high frequency dewatering vibrating screen
1、Symmetrically mounted on the vibration beam of the two same parameters of the vibration motor synchronous reverse rotation, each produces equal size centrifugal force, the two forces in the vertical vibration direction of the opposite force to cancel each other;
2、In the parallel vibration direction of the force is consistent with each other to form a linear vibration force, linear vibration force cycle continuously on the sieve body, so that the sieve body in the buffer spring vibration;
3、At the same time, the buffer spring reduces the dynamic load of the sieve body on the sieve machine support base, the sieve body drives the sieve surface synchronized vibration, the force will be transmitted to the sieve material;
4、The impact of the material in the screen surface thrown up forward dewatering, the material continuously from the feed chute input, through the screen surface for dewatering, under-screen material discharged into the under-screen chute, screen material discharged into the discharge chute.
Motion characteristics of high frequency dewatering vibrating screen
According to the mechanical structure and process parameters, the vibrator of the high frequency dewatering vibrating screen is arranged above the center of gravity of the sieve box, and this arrangement makes the sieve machine trajectory in the feeding end of the ellipse, the middle of the circle, and the discharging end of the ellipse, so that the movement of high frequency dewatering vibrating screen movement trajectory is ellipse – ellipse.
Because of this unique movement characteristics of high frequency dewatering vibrating screen, the long axis of the ellipse at the feed end and the sieve and the angle into an acute angle, the long axis of the ellipse at the discharge end and the sieve surface angle into an obtuse angle. This makes the material in the feed end of the movement speed is greater than the discharge end of the movement speed, to ensure that the material in the sieve and the feed end of the sieve can be quickly loosened, the material layer is thin, so that the fine-grained materials as soon as possible layered contact sieve and penetrate the sieve, the water viscous membrane rupture dehydration; and the discharge end of the material speed is small, you can prolong the material in the sieve surface of the dewatering time, and thus increase the effect of dewatering. The sieve machine has this characteristic, strengthen the dehydration effect.
Advantages of high frequency dewatering vibrating screen
1、Simple and compact structure, high rigidity, high strength, balanced distribution of force
2、The service life is often, the overall service life of the vibrating screen equipment is up to 5 years
3、The screen can be made of wear-resistant polyurethane material, long service life, high screening efficiency
4、Low working noise, the noise is lower than 75 dB, smooth operation
5、Light weight, low power consumption, high vibration intensity (9-12mm), high screening efficiency
6、A full range of varieties, can fully meet the different material characteristics and handling capacity of the screening process requirements
7、The sieve machine operation and maintenance is simple, cost-effective, adequate spare parts, timely and thoughtful service. Below we will introduce about the maintenance of dewatering vibrating screen.
The effect of vibrating dewatering screen on the concentration and particle size of feed material
Vibrating dewatering screen plays an important role in material processing, generally there is concentrated slurry, after vibrating dewatering screen processing, above the solids can reach the screen, and even some coarse sand can reach the dry pile, the water under the screen through gravity settling so that the mud precipitation in the water, the water through the role of the filter press to form recycling.
However, when the vibrating dewatering screen bearing lacks lubricant, it may also cause the dewatering screen sealing device to be blocked, resulting in the temperature rise of the bearing structure exceeding the specified range. The lubrication system of the equipment should be checked in time to ensure that the lubricant is sufficient and clean. If clogging is found, the bearing should be removed for thorough cleaning. If the sealing ring is damaged or the bearing is cracked after wear, the sealing ring and bearing should be replaced in time, and after the dehydration, drying and screening are completed, then the screening and grading of materials should be started.
The ratio of the sieve area of the dewatering sieve to the total area is the opening rate, the larger the opening rate, the higher the screening efficiency and production capacity, but the strength and service life of the sieve surface will be reduced. Square holes have a higher opening rate, so the screen surface is mostly square holes, but the material with high water content and small particle size is better with round holes.
Reasons for rapid deterioration of dewatering screen panels
1、The quality of screen mesh is unqualified. General requirements of the upper screen layer and the lower stress layer fit tightly, if the screen mesh technology is poor, when the screen mesh bottom stress layer fit tightly, the screen mesh layer has no tension, the work of the drill cuttings throwing force is greatly reduced, the drill cuttings can not be discharged.
2、Screen mesh tension is not enough, resulting in screen mesh vibration, generally along the edge of the screen mesh or the edge of the package broken or broken.
3、The vibration motor steering error in adjusting the vibration motor steering, according to past experience, the operator thinks that as long as the drill cuttings go forward, but this method is not applicable to all vibrators. If the vibration motor is wrongly steered inward, although the projectile angle is 45°, there is the force of the drill cuttings rolling backward, which makes the drill cuttings migrate forward much slower, and stays on the screen for a long time, and even leads to the drill cuttings can not be discharged.
4、Many times customers encounter a variety of problems, need to dewatering screen for a long time. May be used for too long is also an important reason for the rapid breakage of dewatering screen.
5、No maintenance. Although sometimes the dewatering screen is damaged due to quality problems is a great concern, but if you buy back the dewatering screen does not carry out maintenance and maintenance, the speed of damage will be accelerated.
The solution of too fast damage of dewatering screen plate.
1、Spray the screen and plugs with water to reduce the stickiness of the plugs, but this method is only applicable to the case where water is allowed
2、Adjust the angle of the screen mesh at the sand discharge port downward, which is conducive to the use of gravity to remove the rock chips, but it may lead to running slurry
3、Improve the quality of the vibrating screen pieces produced by the foundry;
4、Change the mesh number of the screen tube or adjust the flow rate of a single screen tube to ensure that the stopping point of the drilling fluid is close to the outlet of the screen tube, so that the drill cuttings can be discharged smoothly under the lubricating effect of the drilling fluid.
5、Maintenance should be carried out after use, which can play a role in protecting the screen and minimize wear and tear.
Dewatering screen plate easy to damage is a long-standing problem, if the screen plate fixture is often damaged, it is best to replace the screen plate support beam. Dewatering sieve plate damage is caused by a variety of reasons, only specific analysis, in order to ensure the safe and smooth operation of the equipment.
