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1. the working principle of relaxation sieve The unique function of the relaxation screen operation is that the sieve has a double vibration principle and an elastic sieve plate, that is, a double vibration system composed of linear vibration of the main sieve body and additional vibration of the floating screen frame to generate relative motion. Moreover, during the vibration process, the elastic polyurethane sieve plate repeatedly performs tensioning and slackening at a frequency of 800 times per minute to throw the material, so that the acceleration generated by the material on the sieve reaches 50g, which can effectively prevent the sticky material from sticking to the sieve. The plate can prevent the fine material from clogging the sieve hole and significantly improve the screening efficiency. 2. the type of relaxation sieve There are many kinds of relaxation sieves, such as linear motion horizontal sieve surface, linear motion inclined sieve surface, and linear motion banana-shaped sieve surface; all kinds of relaxation sieves have single layer or double layer. Double-layer relaxation screens can be divided into two types: First, the upper sieve plate is a rigid sieve surface, and the lower sieve plate is an elastic relaxation sieve surface (used to use the upper fixed sieve surface to control the upper limit of the inlet particle size of the lower sieve surface to protect the lower elastic relaxation screen surface from damage) . Second, the upper and lower sieve plates are elastic relaxation screens (used for simultaneous screening of fine material grading and powder removal). 3. the technical conditions for the use of relaxation sieve 1. Factors affecting the efficiency of the sieve (1) Feed particle size composition-The most difficult grade to be graded in the material is the size of the sieve size. Therefore, the larger the feed size, the smaller the relative proportion of the material near the mesh size in the same treatment range. The higher the classification efficiency. (2) Material moisture - within a certain range of water (generally referred to as external water <15%), the larger the moisture, the more sticky the material, the easier it is to block the sieve holes, and the lower the classification efficiency. (3) Processing capacity-In the case of the same coal quality, the greater the processing capacity, the lower the classification efficiency. Practice has proved that the depth grading (de-powder) particle size of the relaxation sieve can be reduced to 3 mm, and the screening efficiency can still reach about 85%. 2. Relaxation sieve feed size requirements (1) The single-layer relaxation sieve requires the upper limit of the particle size of the feed to be generally 50 (80) mm; when the content of the sieve under the sieve is >50%, a banana-type relaxation sieve can be considered. (2) When the upper and lower sieve plates of the double-layer relaxation sieve are elastic relaxation screens, when the sieve hole of the upper sieve is 25mm, the upper limit of the feed size is generally required to be <150mm; when the sieve of the upper sieve is 13mm, the general requirement is The upper limit of the feed size is <80-100mm.

Both [pegging" and [blinding" are issues quarry personnel experience every day. Truth be told, there is no miracle solution to these problems, but that doesn`t mean certain screen designs and applications are not capable of mitigating them. Before we identify ways to curtail blinding and pegging, we need to understand the differences between the two. Blinding occurs when screening media is exposed to fine, sticky material. When dirt, minerals and other substances adhere and bridge across the apertures, it creates a thick paste that blocks material from screening through. Pegging ensues when irregular material enters the screen apertures but is unable to pass through. This also becomes a challenge when the stone is about the same size as the holes. A number of variables could be at the root of these issues: clay in the actual deposits, rock types, and the kind of operation you`re running can all have an impact. Essentially, the type of screening media you select must complement your quarry`s process. Because blinding occurs when material sticks together, the screens should be designed in a way that disperses the paste consistently. Generally, integrating flexibility into the screening media can do this. Small, square apertures are to be avoided when it comes to blinding. Why? Because they provide the material too much of a surface area on which to accumulate. Using long-slot apertures with fine wires, which will emphasise vibrations and break up the paste, can solve this problem. Keep in mind that flexibility is largely dictated by the thickness of your screen, so if you`re handling matter that tends to stick together, choosing finer media may be the best solution. However, there are instances when the aforementioned solution isn`t much help – primarily because steel wire doesn`t possess as much flexibility as polyurethane or rubber, for example. Blinding typically transpires when earth is exposed to water, the latter of which greases polyurethane. Essentially, water is a natural lubricant to polyurethane, allowing material to easily slip through the apertures. HITTING THE PEGS Ultimately, the frequency at which pegging occurs is largely dictated by the kind of crusher a quarry uses and the type of rock the facility is processing. Splintery material and rocks shaped at an odd angle are likely to wedge in screen apertures. So the type of screen you select isn`t the be-all and end-all to eliminating pegging, but making the right choice can mitigate the problem. Ripple screens are designed so each wire is attached to the hooks on each end, allowing the unit to flex independently in certain areas. This allows the apertures to expand (albeit minimally) to free trapped stones intermittently. But do you choose polyurethane or rubber? Again, it depends on your operation. Polyurethane is the best choice of the two if you`re screening with water. Lubricating the screen enables trapped stone to slip through relatively easily. Rubber is best for dry operations but the media must be designed so the bottom of the panel is slightly larger than the top. This will allow rocks to be forced through the screen once any pressure is applied. As mentioned at the beginning of this piece, there`s no single screen design that will completely remove pegging and blinding from the equation – but at the same time there are ways to reduce these issues.

Dewatering screens have long been considered important instruments in sand processing – and an effective means for producing drier, cleaner end products, particularly in the capture and retention of ultra-fine materials. The dewatering screen`s origins may be in the coal industry, but it has made a home in the aggregates world. Since appearing in the North American market in the late 1970s, the dewatering screen has become the [go to" piece of equipment for economical removal of water from sand. Here are eight reasons why dewatering screens play such a large role in the production of clean quarry products. 1. A drier material Several pieces of equipment are used to reduce moisture content in sand. A separator or siphon-assisted hydrocyclone produces an underflow material of 22 to 35 per cent moisture. The material can be stacked on a drainage field or discharged to a dewatering screen for additional moisture removal. Discharging the material directly onto a conveyor belt usually creates a housekeeping issue due to the remaining free water. A fine material screw washer produces a discharge with a 15 to 30 per cent moisture content. While the product can discharge onto a conveyor directly, material can cling to the belt and create a housekeeping issue. The dewatering screen achieves between eight and 20 per cent moisture, depending on the material`s physical characteristics. Despite the retained moisture range, the dewatering screen discharge is drip-free and can be easily conveyed, loaded into a truck or placed in a bin. A dewatering screen is a low cost solution when feeding dryers, putting material on conveyors, loading trucks or discharging to other equipment that requires the lowest percentage moisture. 2. Handling multiple products The use of longitudinal dividers allows up to three products to be dewatered on one screen. Many applications feature a two-stream process where fine and coarse streams can be kept separate or blended to create specialty products. Utilising one dewatering screen for multiple products reduces the overall footprint of equipment and reduces capital and operating costs. 3. Integration with equipment Dewatering screens fit well into many applications to yield a drier product, capture ultra-fine material or allow better control in the process. The combination of a hydrocyclone or separator with a dewatering screen creates a wash system with a higher efficiency level and a drier product yield. The screen underflow can be recirculated into the hydrocyclone feed for recovery or removed as undesired. Ultra-fines recovery plant Generally, a screen will make a classification based on the media openings. When trying to capture material that would normally pass through the media, a dewatering screen can be used in combination with a hydrocyclone to recover ultra-fine material before it goes to a settling pond. Even though some of the fines will pass through the screen media, they will remain in the system. The hydrocyclone overflow is the only exit point for the fine material, and it is operated at a high pressure to retain the material. Equipment such as attrition scrubbers will not operate at optimal levels when the material is too wet. A dewatering screen will produce a predictable moisture, which will allow better process control. The material can be adjusted to the correct percentage moisture through the addition of water at a controlled rate. 4. Wide range of size gradations Since the main purpose of a dewatering screen is to reduce the percentage of moisture in material, it can handle a wide range of particle sizes. From as large as 13mm (0.5") down to 37 micron (400 mesh) fines, a dewatering screen can be configured to handle material in the size that is needed. As the dewatering screen is designed to blind off the media openings, material that would normally pass through is retained while the water flows through. When used with a hydrocyclone or separator, a dewatering screen is extremely effective in retaining material and producing a dry product. 5. Media alignments for sizing cuts A dewatering screen is set up to blind the screen media, to retain material to the overs and allow the water to report to the unders. With this mind, it is still a screen, and the media can be adjusted to perform sharp size classification. The inclined discharge continues to promote the removal of water from the material. The media does not have to be continuous in purpose. One section can be configured for size classification, while others are configured for the dewatering requirement. Spray water can be used to increase the size classification efficiency. 6. Addition of spray water While it is preferable to address fines removal upstream, there are situations when fines remain in the product. Adding water to a dewatering screen may seem counterproductive but it can have a significant impact on removing unwanted fines. The media will retain the desired material, while the fines will travel with the water and report to the screen`s underflow. The water amount and the added location will have an impact on the effect but, generally speaking, water is added at the feed end. 7. Low power Fitted with two vibrating motors or a single motor to drive exciters, dewatering screens record significantly lower total power usage (in kilowatts) than similar capacity equipment. With the recommended percentage moisture in the feed of 50 per cent or higher, a dewatering screen can accept a variety of feed sources. Under some circumstances, the feed can go below 50 percentage solids, but it can affect the final product dryness or total capacity. When the feed`s water content is too high, it may require more equipment, such as a hydrocyclone, to decrease the moisture percentage prior to introducing the material to the dewatering screen. 8. Low maintenance The screen media and springs/buffers are the main items that will need replacing. These items, along with the sideliners and discharge lip, are the only wear parts, and all have a long lifespan. Motors and structural components are designed for heavy-duty applications and have a low rate of failure. For these eight reasons, a dewatering screen can be a welcome addition to a quarry plant when producers are striving to remove moisture and improve productivity. In worldwide, Huatao Group is the professional supplier for screen mesh of sand and aggregates processing range.

The available range of tufflex screens is extensive, with aperture sizes ranging from 1.5mm to 45mm and square and rectangular aperture shapes, similar to woven wire. The wire rope diameter ranges from 1.5mm to 12mm, with custom-made rectangular slots as fine as 0.7mm wide. The construction varies with either fully or partially welded wires. Sheets of poly can also be welded on for [hot spot" impact protection or enhanced abrasion protection along the hooks. And we also can design the tufflex screen as customer's requests, we would like to research and develop new screen to supply more helps for quarry.

Tufflex screens were developed in Japan 20 years ago to supply the local quarry industry. These lightweight screens are used in the sizing of aggregates for the Japanese concrete and road building industries. The benefits of longer wear life, lower pegging and minimal blinding have made Tufflex screens the screening media of choice for many of their processing plants. The Japanese standard JIS A 5015 (Particle size for road specifications in Japan) defines the three main aggregate specifications as No. 5, No. 6 and No. 7, ie 20mm, 13mm and a 5mm stone. The screens used to create these specifications are what Tufflex screens were designed for, and they are suitable for both the wet and dry process. It has been observed that Australian aggregate specifications are very close to the Japanese ones. In a growing number of sites around Australia, it is the sizing screens used in the creation of these specifications where Tufflex screens are operating successfully. While there are a set range of apertures (1.5mm to 45mm square) to choose from, the Tufflex process has great flexibility in manufacturing unique aperture combinations to rope diameters and aperture slot lengths. For example, in some quarry plants in Japan, a 14 aperture screen is used as the bottom deck for their No. 5 spec (20mm to 13mm) or the top deck for the No. 6 spec. The Tufflex specification is an 8mm rope on top and a 6mm rope from hook to hook, a combination not available in traditional woven wire. Long-slotted apertures, ie 8 x 340mm, are used in some side-tensioned equipment where flexibility of the screening surface is needed. This type of aperture, while possible to weave in wire, would not have the mechanical stability for a vibrating application, whereas Tufflex screens were developed with this in mind. These larger configurations can also be used as an alternative to harp/piano screens. Another construction variation of Tufflex is the ability to not weld all intersections of the ropes. It has been found that not welding every intersection creates a screening surface with extra vibrations. This works well on dust decks, especially when moisture builds and the potential for blinding increases. Features that can be built into the Tufflex screen include stainless steel in lieu of mild steel for the hook sheathing, a poly sheet welded to protect the exposed metal of the side hooks from wear, clearance for centre bolt holes and sealing of screen edges, ie discharge flaps.

Tufflex works best when the maximum feed size. For example, if the drop height for the feed material is 700mm, the maximum size of the feed material is 45mm diameter for a 10mm to 12mm diameter rope. In a review of applications to date, Tufflex stands out from other screening media in: 1. Sand screens in a gravel wash plant offering longer wear life and open area. 2. Dust screens where increased moisture in the dust allows full production, with no blinding. 3. Sizing decks where pegging is minimal with the partially welded variation, and the smallest rope diameter. Tufflex screens` unique combination of common materials and processes has created a product with applications in areas well beyond hooked edge screens.