Large vibrating screens represent a unique challenge for Manufacturers, Plant Designers, and Plant Operators. The inherent mode of operation for vibrating screens is self-destructive. More often than Manufacturers admit, Designers plan for, or Operators staff for, a vibrating screen succeeds and self-destructs. This is a problem. It can magnify with larger vibrating screens.
Vibrating screen structures are subjected to nearly 250 million fatigue cycles in an operating year. The design and construction of these structures are critical in achieving reliable screen performance. Regardless of screen size, the maxims for design continue to be:
A screen design meeting these criteria yields the lowest cost per ton performance. Large screen technology is evolving more scientifically than did the development of small screen technology. As vibrating screen designs increase beyond six foot widths, reliable designs result from sophisticated engineering methods and manufacturing techniques. In addition, large screen technology amplifies the direct relationship of production cost and reliability.
Static Stresses: At rest, motionless, a vibrating screen structure is subjected to the force of gravity, at a minimum. A vibrating screen must first support its own weight. Other motionless stresses are present in the structure as a result of cutting, bending, welding, burning, drilling, assembly, tolerancing, and manufacturing variances. Quite simply, these stresses exist whether or not the screen is operating.
The second step in FEA can be considered the construction of structural loads. These include the imposition of static, dynamic, material, and fatigue conditions on the mathematical model, which approximates the load conditions. An example would be to describe a structural misalignment and the forces input co bolt up this structure through the misalignment.
Reliable vibrating screen designs are dependent upon the proper marriage of a firms manufacturing capabilities and the requirements of the design. It is not reasonable to expect that closely toleranced airframes will be successfully produced in a metal-bending job shop. As design safety factors narrow on larger screens, manufacturing techniques evolve which minimize production variables. Design tolerancing is necessarily compatible with manufacturing accuracy.
Residual metal working stress is the left-over stress in metal when melted or formed into a shape. It is a result of a materials resistance to change shape. Stress concentration sites are more commonly termed notches or stress risers. These areas are not stresses, but sharp geometric transitions or reversals in a structure. Stress loads focus their effect on a structure at these sites. Experience has proven that the methods and procedures of structural assembly can result in preloading screen bodies with excessive static stresses. The scope of this discussion is limited to the discussion of welding, forming, and bolting as they relate to conditions described above.
The side plate of a vibrating screen literally bristles with fasteners. Multi-shift production facilities, as well as maintenance crews, quickly realize the merits of this system. Unlike conventional threaded fasteners, swaged bolts exhibit a distinctly different physical appearance when installed versus loosely installed. The guess-work and wasted efforts to repeatedly insure all bolts are properly torqued are eliminated. A second-shift assembler need not consult with his first-shift counter-part regarding loose or torqued bolts . Sound maintenance practice precludes the reuse of major structural fasteners. A huck-type fastener is destroyed during removal. Normal threaded fasteners depend on proper installation torques to achieve the optimum clamping force. Registered torque wrench values may not be indicative of the true values due to the effects of thread lubrication and frictional force of the fastener face on the bolting surface. Swaged fasteners are installed strictly in tension at an optimum preset tensile load. The positive clamping values are reliably consistent. Installation error is minimal. Replaceable, non-structural components may be installed with conventional fasteners.
Anticipated operating and maintenance costs over the productive life of a processing plant design significantly influence the go or no-go decision to build the plant. Large vibrating screens can both add to and reduce the magnitude of these costs. Plant designers must examine the serviceability of these large units. This includes the complexity of installation, start-up, routine maintenance, major repairs, and operating instrumentation. In assessing these costs, the likely condition exists somewhere between the extreme of a screen leaping momentarily out of position long enough to repair itself and swarms of mechanics covering the unit like bees on honey over several production-robbing shifts.
As larger vibrating screens are used, their size will exceed cost-effective shipping limits fully assembled. Screen manufacturers will join the ranks of other major equipment suppliers in on-site assembly and testing of these units. The incremental costs associated with these efforts must be considered in evaluating the plant construction and start-up costs.
The use of larger vibrating screens results in the dependence of a larger percentage of total plant production on each unit. It is imperative that plant operators maximize the production availability of large screens. This effort is enhanced by carefully planned operating and maintenance procedures. Since volumes have been published on efficient and successful preventative maintenance programs, this discussion will not deal with that topic. There are several suggestions that can be made to help potential big screen users better position themselves to react to the service requirements of these units.
As trite as it sounds, talk to potential screen suppliers specifically about the service requirements of their screens. Determine how recently a manufacturer has entered the wide screen market. Was this entry preceded by years of research and testing? There are generally two major shortfalls in a hastily planned new product introduction. Invariably, replacement parts availability is a problem. Second is the frustrating response to a frantic maintenance question, The only guy who knows that unit is on an island in Indonesia. Solidly planned programs will have organizational depth.
The labor pains, which have normally accompanied the birth of new vibrating screen designs, have been no less severe with the gradual introduction of large, high-capacity screens. More difficulty would have been encountered without the aid of advanced engineering and manufacturing techniques.
The development of vibrating screens over the last century has seen many variations to suit the exacting requirements of industry. Indeed, as each year passes, industry has presented the challenge to screen manufacturers of supplying larger machines than those used in the past and the question is often posed what is the maximum limit?
Innovations introduced such as bouncing ball decks, heated decks, tri-sloped and bi-sloped decks and pool washing features have all sought to achieve improved anti-blinding results and improved capacity for a given screening efficiency. Although the benefits achieved by the inclusion of these features were shown in some cases to be beneficial, the application of good throw in conjunction with the required G force in the operation of the screen has proven in screen performance today, to provide maximum screening efficiency and capacity. The importance of good throw is often overlooked and should be the first consideration when wishing to maximize screen capacity.
For a straight line motion screen the throw is the distance between the extremities of motion. For a circular motion screen, the throw is measured across the diameter of motion but if the screen has an oval motion, throw is measured by taking the mean of the major and minor axes.
The throw which is specified for a particular application is determined on a screen body eccentric weight basis and normally does not take into allowance the load of material which will be handled by the vibrating screen.
Therefore it is imperative that the live weight of the vibrating screen is sufficient to maintain, within reason, the throw which has been originally specified so as to effectively handle the loads being fed to the screen.
The above comments relate essentially to a dry screening application but in wet applications where metalliferous pulp is received on the screen, the benefits of a large throw in terms of increased screen capacity have been demonstrated in commercial practice. The ideal machine for receiving pulp for wet screening or desliming, dewatering etc. is a horizontal screen. Among other reasons, the horizontal screen provides the benefit of long retention time for handling the pulp. Also the straight line motion provided with good throw imparts a positive breaking of surface tension present between the pulp and the screen deck within the apertures.
The inclusion of large vibrating screens in the design of new plants by planning engineers and metallurgists responsible for such work, particularly where large associated equipment is available, is inevitable and is in fact a progression of size we have witnessed over the years.
We should remind ourselves that size progression could not proceed without the accumulation of experience in screen body design, in application knowledge, improved quality of manufacture and refinements of mechanism design with regard to achieving improved bearing life which allows the use of a good G force.
As referenced previously G force and throw are interrelated and therefore with the good G forces available today in the modern vibrating screens, the way is clear to taking full opportunity of increasing throw to handle the high tonnages which can be expected and are currently experienced on large vibrating screens.
Where abrasion of the screen deck surface is severe as in most metalliferous mining applications, and the separation sizes are in the order of mm to 50 mm aperture sizes, polyurethane screen panels are now in common use because of their excellent resistance to wear. The trend in the use of polyurethane panels in the metalliferous mining industry is quite definite and in fact in the major mining operations in Australia at least, the use of polyurethane screening panels is firmly established.
With reference to metalliferous tailings the need for dewatering presents a new dimension. The amount of tailings produced is very much greater since some 98-99% of mined ore is rejected in tailings form compared with varying amount of 3 to 5% rejected in a coal washing operation. Furthermore with dewatering of metalliferous tailings, using equipment as mostly used in coal washing would present maintenance problems because of the more abrasive nature of the tailings and therefore for that reason it is customary to discharge all metalliferous tailings slurry to a dam.
The screen-cyclone system relies on the blinding tendency of the screen deck apertures for its success, using either stainless steel wedgewire or polyurethane deck panels in conjunction with the use of cross dams spaced every 120 cm along the deck surface. When considering the screen-cyclone system it is important to appreciate that the screen function is not one of separation at a given aperture size but bleeding of water through the restricted deck apertures caused by the semi blinding condition. That is, if the deck apertures were to remain completely free of blinding, which is not the case, practically all of the tailings would pass through the apertures in the first pass and would not allow the system to function.
The underflow from the primary cyclones should be deposited on the horizontal section of the screen deck at the feed end where the maximum of water should be removed with the assistance of an additional section of wedgewire located on a 45 inclined back plate to remove free water that has accumulated on top of the bed of slurry most solids having stratified to the deck surface. The underflow should be evenly distributed across the width of the screen at minimum velocity, so as to allow the full benefit of stratification provided by the screen.
The actual results from the initial test run taken on the pilot plant installed at Philex Mining Corporation, Philippines in March, 1980 are as follows using a gravitated flow of tailing slurry from the concentrator.
The problems involved in installing, maintaining, and operating large vibrating screens have been summarized and discussed, based on a survey of current use of such screens in selected North American mineral processing applications. Practical, effective solutions for the more serious common problems are described, along with some recommendations on design practice for specifying, selecting, and installing large screens.
In order to properly assess the information gathered through the survey questionnaire, the results pertaining to each group of applications will be presented and discussed separately in the following section. The small number of installations actually surveyed makes any rigorous statistical interpretation of the data difficult, therefore the information is presented in a generalized fashion. Notwithstanding the small sample of operations as compared to the total number of such large screen installations around the world, the results are felt to fairly represent typical operating, maintenance and installation problems and practices in the sectors of the mineral processing industry the survey covered.
The results reported in this section refer to inclined vibrating screens used in conventional crushing and screening plants. Four operations replied to the survey questionnaire, all four are medium sized producers, primarily of copper concentrate, some with significant by-product production of Mo or Ag. Daily throughputs range from 5,300 tons to 38,000 tons.
The major problem areas reported by the users of these screens were bearing failure and replacement and side plate cracking. The minor problems reported were loose bolts, seals and routine wear items such as cloth and liner changes. Reported availability of the screens ranged from 92-96%. At one operation, the crushing and screening plant is oversized and operates only one shift per day, therefore downtime for maintenance is readily available and actual availability was not reported.
The maintenance of large vibrating screens in conventional crushing applications would normally consist of the regular replacement of wear parts, such as liners and screen cloths, as well as regular lubrication of the bearings and other moving parts as recommended by the manufacturer of the particular screens in use.
The operations with large horizontal vibrating screen installations replying to the survey questionnaire were Syncrude Canada Ltd., Climax Molybdenun (Henderson Operations), Quintana Minerals and Fording Coal Ltd. As previously noted, the screen applications at these operations are all basically very similar, involving wet screening of relatively large tonnages of slurry feed.
The major problem areas with these screen installations once again include bearing failure and side plate cracking in three out of the four installations. The fourth installation, Henderson, reported major problems with the mounting springs and feed lip both of which have presently been rectified to the point where only minimal unscheduled downtime occurs.
The major problems associated with the horizontal screens were with bearings and side plate cracking, and were evident soon after commissioning. Major efforts were undertaken at all the operations to correct the serious problems.
Large vibrating screens are normally selected for applications where multiple screens would be more costly to purchase and install. There have been a considerable number of large screen installations in a variety of mineral processing applications, therefore a considerable amount of operating data with respect to the screen components and performance has been gathered. From the plant designers viewpoint the design of a screen installation should consider the following areas:
The design of a large vibrating screen installation requires close attention to not only the screen itself, but also to the ancillary structures, maintenance procedures and personnel comfort and protection.
Large vibrating screens represent a considerable investment in equipment alone. In addition the loss due to interrupted production should one of these units go out of service can be economically much more severe. As plant tonnages have risen and larger equipment has been utilized in single trains or a small number of multiple trains, the risk of having a single large screen down for any length of time has become too great to ignore.
The quarry vibrating screen is mainly used to screen gravel, and the quality of the screen mesh determines the material screening efficiency. Therefore, quarry investors or equipment purchasers will ask the manufacturer for information about vibrating screen media types when choosing a vibrating screen.
Rayco designs and manufactures a complete set of high quality and cost-effective rubber screens. They are used to treat the roughest and most abrasive products, such as gravel, coal, slag, etc. Rubber material is soft and powerful, can absorb shock and have long service life, which not only can reduce the downtime, but also makes installation easier and faster. If noise reduction is required, rubber screens are good choices.
Rayco rubber sieve can be divided into two kinds: tension and modular. The tension type can be installed as a circular vibrating screen and replace the original metal screen or polyurethane screen. The modular type can be installed in many ways, which can better save operating costs.
The polyurethane screen is made of polyurethane and embedded in a steel frame. It has a specially designed fastening hook to clamp the mesh to the separator. Polyurethane screen has excellent performance in mining crushing and aggregate screening industry. Different sizes and types of mesh hole ensure high screening efficiency and smooth surfaces. Polyurethane materials make mesh noise much lower than braided vibrating mesh or perforated mesh.
Our polyurethane screens can effectively screen materials for many industrial applications, such as dehydration, mining, sand, stone, gravel, etc. Polyurethane is ideal for high wear areas in both wet and dry processing applications.
THe high-strength woven wire screen is made of best steel wire like manganese steel wire, galvanized steel wire and stainless steel wire. The mesh hole can be square, rectangular, or longslotted. With a variety of woven types, it can be suitable for different screens and materials.
The perforated screen is made of a metal plate with high compressive strength after punching. Compared with woven vibrating screen, porous vibrating screen has a smooth surface, which can ensure higher screening and separation efficiency.
Y Vibrating Screen, also known as Y Circular Vibrating Screen, is researched and developed by SBM on the basis of introducing international classical screening technologies. It is an advanced screening tool at home. Meanwhile, it is an indispensable classifying device in such fields as ore beneficiation, aggregate production, disposal of building wastes or solid wastes and coal dressing.
Y Circular Vibrating Screen follows classical structural design of screening equipment, and its performance is fully guaranteed. In addition, SBM strengthens the design of vibration exciter, i.e. the vibration source is more stable, and the exciting force is more powerful.
In order to satisfy various graded operating requirements after the intermediate-coarse crushing and intermediate-fine crushing, SBM equips multiple types of screen nets for Y Vibrating Screen. Users can freely select different numbers of layers and specifications of the screen which can satisfy different production demands through simple screen replacement operation.
Years of practical researches show that V-belt transmission device can effectively avoid the transmission of axial force during the vibrating process and decrease the failure rate. Directly connecting the motor and equipment through floating support and V-belt can effectively reduce the impact on the motor, greatly improving the life expectancy of motor and V-belt.
The structure of Y Vibrating Screen boasts small vibration amplitude, high frequency and big dip angle, while grants the screen with higher screening efficiency and bigger capacity. The vibrator uses dilute oil lubrication and its bearing has large clearance, so noises are low yet the service life is long. Spare parts have excellent universality, which makes later maintenance get easier.
SBM has dozens of CNC (Computer numerical control) machine production lines. From steel plates' cutting, bending, planning to final painting, all steps can be controlled numerically. High processing precision assures that key parts have higher standards.
SBM, as a prominent enterprise integrating machine production and sales in mining machinery industry, is dedicated to be responsible for every product. Meanwhile, SBM always makes every effort to offer customers comprehensive technical services and sufficient spare parts to let them be free from worries about project operation.
A Y Vibrating Screen mainly consists of screen box, screen net, vibrator, damping spring device, chassis and other components. The side plates are made of high-quality steel plates. They are connected with the beam and the exciter base by high-strength bolts or ring groove rivets. The cylinder-type eccentric shaft exciter and the eccentric block are used to adjust the amplitude. The vibrator is installed on a side plate of the screen box. Driven by the motor, the eccentric block of the vibrator would rotate at a high speed under the motivation of triangular belt. High-speed rotation further exerts strong centrifugal inertia force to stimulate the screen box move in a circular motion within specific amplitude. During operation, materials on the inclined screen surface are subjected to the impulse transmitted from the screen box so that they are put in a continuous throwing motion. When materials fall onto the screen surface, particles smaller than the screen size are sieved out to achieve classification.
Product pictures and parameters about models, data, performances and specifications on this website are for reference only. There is a chance that SBM may make changes on above-mentioned information. For specific messages, please refer to the real objects and user manuals. Without special instructions, SBM keeps the right to explain all data involved in this website.
A WIRE RANGE OF PARTS FOR YOUR SCREEN BOX Vibrating screens need to vibrate in a linear motion, the screens need to be correctly tensioned and washing requires proper nozzles. We offer a wide range of accessories for vibrating screens to ensure proper and safe operation.
Screen panels require proper tension and bedding to perform at their best with minimum breakdowns. Cappings act as a bumper between the deck and screen mesh. It is very important to fix the screen mesh tight to the deck as a lose connection will destroy the screen in a short period of time.
Rubber buffers are an important part of a vibrating screen. Screen operation should be strictly linear in line with the material flow and side movements should be minimised. Especially during start/stop operations, side movements increase as the screen passes through amplitudes close to its natural frequency and it resonates. Side rubber buffers prevent the screen from moving sideways.
While a large number of engineers try to minimise the vibrations in different applications, vibrating screen manufacturers try to make the best of it. Proper vibrating patterns are not possible without flexible mounts. Springs are the most common type of vibrating screen suspension. They are durable and easy to install and service.
Washing is one of the most important stages in aggregate and mineral processing applications. Generally, washing is performed by spraying water under pressure on the top of the material flow. Washing nozzles are special attachments to the pipes that spread the water over a wide coverage area. This water washes off the clay and dirt.
Declogging rods have been developed to further improve the self-cleaning properties of anti-clogging screens. Declogging rods bounce on the PU strips and create additional shock that helps to shake off stubborn sticky material from the panels. Declogging rods can be connected in multiple parts to completely cover the screen area.
A vibrating screen is a large mechanical tool used to separate solids, liquids and powders. Industries as diverse as mining operations, chemical companies and construction firms utilize these tools to help sort and clean items. Using gravity, motion and mesh screens, these tools perform the work of several people in a fraction of the time.
A vibrating screen separator is roughly the size of a metal garbage dumpster. It is constructed, many times, of a solid metal such as steel and has two open sides so users can visually monitor the progress of the screen. Most vibrating screens have four or more levels of screens stacked on top of one another. The screens are made of wire mesh and come in a variety of sizes in order to accommodate different jobs.
The vibrating screen operates by having the items that are to be separated, such as marbles of different sizes, placed on the screen on the top layer. The entire machine vibrates in a gentle circular motion to work the material through the screens and separate any impurities. So the marbles of different sizes would slowly work their way down the many layers of screens, usually having the largest openings at the top layer and getting smaller as the marbles head toward the bottom. The result is a collection of marbles sorted by size, and any dirt and extra material is shaken off. The amplitude of vibrations can be adjusted in order to be gentle for delicate material and more vigorous for tougher items.
The mining industry is one of the biggest users of vibrating screen technology. Taking ore and minerals from the ground results in many impurities, so these organizations load goods into a screen until dirt and non-valuable rocks are shaken from material such as coal, iron and ore. Screens also are utilized in manufacturing, especially when metal items, such as ionized bolts and screws that need to be submerged in a bath, need to be dried. Here, full containers of liquid and metal can be poured through the screen and separated with the vibrations to ensure that they dry completely. Disparate industries such as archaeology, metallurgy and construction also utilize vibrating screen technology to get their jobs done.
According to different structure and use, vibrating screens usually be devided into many types by the vibrating screen manufacturers. Below wil introduce the top 10 vibrating screens, and how to choose the right vibratory screen?
linear vibrating screen is driven by double vibrating motors. When the two vibrating motors are rotating synchronously and reversely, the excitation force generated by the eccentric block offsets each other in the direction parallel to the axis of the motor, and overlaps into a resultant force in the direction perpendicular to the axis of the motor, so the motion track of the linear vibrating screen machine is a straight line.
Working Principle:The two motor axes of the linear vibrating screen have an angle of inclination in the vertical direction relative to the screen panel. Under the combined force of the exciting force and the self gravity of the material, the material is thrown on the screen surface to jump or move forward in a straight line. Through the multi-layer screen panels, a variety of specifications of materials are generated, and discharged from their respective outlets, so as to achieve screening and classification. linear vibrating screen is suitable for screening various dry powder or granular materials with particle size of 0.074-5mm, moisture content <7%, and no viscosity. The feed particle size is not more than 10 mm.
Circular vibrating screen is a new type of vibrating screen with multi-layer screen and high efficiency. According to the type of materials and the requirements of users, the high manganese steel woven screen, punched screen plate and rubber screen plate can be used. The circular vibrating screen is installed in the seat type. The adjustment of the screen surface angle can be realized by changing the position and height of the spring support.
Working Principle: The motion track of the screen box of the circular vibrating screen is circular. The circular vibrating screen uses the inertia exciter to produce vibration. The main shaft fixed on the screen box is driven by the motor to rotate at high speed, and the eccentric body installed on the main shaft rotates with it, generating centrifugal inertia force, so that the screen box that can freely vibrate will produce vibration similar to the circular track.
Circular vibrating screen is widely used in the materials classification of mining, building materials, transportation, energy, chemical industry and other industries because of its long flowing line and many screening specifications.
Elliptical vibrating screen is a vibrating screen with elliptical motion track (Elliptical Shale Shaker), which has the advantages of high efficiency, high screening accuracy and wide range of application. Compared with the ordinary sieve machine of the same specification, it has larger processing capacity and higher screening efficiency.
Triaxial elliptical vibrating screen is widely used for the screening operation of sand and stone materials in sand plant. It is the ideal screening equipment for all kinds of mines, quarries and mobile screening stations.
Working Principle: The power is transmitted from the motor to the main shaft of the exciter and the gear vibrator (speed ratio is 1) through the V-belt, so that the three shafts can rotate at the same speed and generate the exciting force. The exciter is connected with the high-strength bolts of the screen box, resulting in elliptical movement.
Materials on the screens do high-speed elliptical movement along with the screen machine, so as to achieve uickly separate, sift and move forward, and ultimately complete the classification of materials.
The working surface of the roller screen is composed of a series of rolling shafts that arranged horizontally, on which there are many screen plates. When working, the fine material passes through the gap between the roller or screen plate, large blocks of materials are driven by rollers, moving to the ends and discharging from the outlets. Roller screens are mostly used in the traditional coal industry.
Working Principle: For the rolling shafts are arranged according to different working angles, the speed of the material is faster when it runs in the position with higher working angle; the speed of the material is slower when it runs in the position with lower working angle.
When two kinds of materials running at different speeds converge at a certain position on the screen surface, they start to move axially, so that the materials are evenly distributed on the screen surface, and the screening efficiency is improved.
Rotary vibrating screen is mainly used for the classification of materials with high screening efficiency and fine screening accuracy. Fully closed structure, no flying powder, no leakage of liquid, no blocking of mesh, automatic discharge, no material storage in the machine, no dead angle of grid structure, increased screen area.
Any particle, powder and mucus can be screened within a certain range. Sieve to 500 mesh or 0.028mm, filter to 5 microns minimum. It can be used for classification, classification and filtration in food, chemical, metal, mining and other industries.
With the help of the heavy hammer installed at the upper and lower ends of the motor shaft, the rotary motion of the motor is transformed into a horizontal, vertical and inclined three-dimensional motion, which is then transmitted to the screen surface to make the material do an outward involute motion on the screen surface. Working Principle: After the rotary screen is started, the eccentric blocks of different phases at the upper and lower ends of the vibrating motor generate a composite inertia force, which forces the vibrating body of the rotary screen machine to rotate again and again, and the screen frame continuously moves to and fro under the action of the vibration force, and then drives the screen surface to vibrate periodically, so that the materials on the screen surface move in a positive and directional manner together with the screen box. Materials smaller than the screen meshes fall to the lower layer, and the materials larger than the screen meshes discharged from the discharge port.
High frequency vibrating screen is also called high frequency screen for short. High frequency vibrating screen (high frequency screen) is composed of exciter, pulp distributor, screen frame, supporting, suspension spring and screen, etc. High frequency vibrating screen is the most important screening machine in mineral processing industry, which is suitable for completely wet or dry raw materials.
Working Principle: Different from ordinary screening equipments, high frequency screen adopts high frequency, which destroys the tension on the pulp surface and makes the fine materials vibrate at high speed on the screen, accelerates the separation of useful minerals with large density (specific gravity), and increases the probability of contact between the materials with smaller than the separated particle size and the screen holes.
As a result, high frequency screen results in a better separation conditions, which makes the materials that smaller than the separation size (especially with larger specific gravity), and pulp pass through the screen holes together to complete the screening. High-frequency vibrating screen is usually operated at an inclined angle 0-25, up to 45, and the operating frequency range is 1500-7200r/m.
Grizzly screen has simple and solid structure, no power consumption, no moving parts, low equipment cost and convenient maintenance, but the productivity is low, the screening efficiency is not high, generally 50% 60%, and the mesh is easy to be blocked.
Working Principle: Generally, the grizzly screen is placed in an inclined position, and the materials are dumped at the high end. Under the action of its own weight, it slides down the screen surface, and the particles smaller than the gap or hole on the screen surface pass through the screen to achieve classification.
Banana screen is mainly suitable for the classification of large and medium-sized materials with high content of fine particles, and it can also be used for dehydration, demineralization and desliming.
Working Principle: During operation, the motor is connected with the vibration exciter through the V-belt or soft connection. The motor drives the eccentric shaft to rotate to generate centrifugal inertia force, which forces the screen box to vibrate. After the materials fall into the screen from the feeding inlet, they move forward rapidly under the action of the vibration force, loosely and pass through the screen.The thickness of the material layer of banana screen from the feeding inlet to the discharging outlet is constant. The ratio of the material quantity to the flow speed on the screen of each section is stable, the material layer is high and uniform. The screening efficiency of banana screen is higher, which is 1-2 times higher than that of other screening machines with the same effective area.
Heavy inclined screen can be applied to the treatment of debris from quarry, mine and building demolition, the treatment of topsoil, the recycling of construction materials, the screening of gravel, and the screening of gravel and aggregates.
Working Principle: The screen box shaft is driven by the motor installed on the auxiliary frame through three V-belts, the auxiliary frame is rigidly connected with the machine underframe, and the screen box spring is used to support the screen box.Inclined screen usually adopts 2-4-layer screen panels, and is fixed on the inclined frame at an angle between 15 and 30. The material can be screened into 3-5 grades at the same time.
Horizontal screen has the advantages of both inclined screen and linear vibrating screen. horizontal screen has the features of good screen permeability, large processing capacity and small installation height.
The installation angle of common vibrating screen is 15-30, while the installation of horizontal screen is parallel to the ground, or slightly inclined 0-5. Horizontal screen is an ideal equipment for all kinds of mines, quarries and mobile screening stations.
Working Principle: Horizontal screen is designed with oval stroke. The advantage of this design is that it can change the oval big diameter length and angle of throwing material stroke to meet the best needs of vibrating screen. The oval stroke is easy to adjust by center gear, counterweight wheel and motor speed.
Different types of vibrating screens can be used for the same material to get different screening effects. The reasonable selection of vibrating screen is an effective way to improve vibration efficiency and maximize economic benefits. Generally, you need to consider the following 5 tips:
When choosing vibratory screen, the material characteristics should be taken into account, including the content of material particles under the screen, the content of difficult screen particles, material moisture, the shape and specific gravity of the material, and the content of clay.
Tips: Heavy vibrating screen is used for materials above 200mm; circular vibrating screen is used for materials above 10mm; linear vibrating screen and high frequency vibrating screen are used for desliming, dewatering and grading.
When selecting the vibratory screen, the screen areas, layer numbers, shape, size and area ratio of the screen holes, as well as the motion mode, vibration frequency and amplitude of the vibrating screen should also be considered.
Tips: In order to keep the screens under good working conditions, the ratio of screen length to width should be in the range of 2-3; when there is much viscous mud and high moisture in the material, double deck screens should be avoided as far as possible.
Vibratory screens need to be selected according to different screening purposes. If it is necessary to pre screen materials, circular vibrating screens are generally used; for the classification and screening of crushed materials, large vibrating screens and probability screens are selected; for the deionization and dehydration of materials, linear vibrating screens are better; if it is necessary to desliminate and clean up materials, probability screens are used.
When selecting the shale shakers, it also needs to be considered according to the processing capacity of the production line, screening method, screening efficiency and the tilt angle of the shale shakers.
Professional vibrating screen manufacturers could provide competitive vibrating screen price, diversity customized vibrating screen models, timely after-sales service, spare parts and can continue to provide services for customers whole production circle.