Polyurethane Screen Polyurethane Sieve Panel Polyurethane Mining Screen Polyurethane Dewatering Screen Polyurethane Grading Screen Polyurethane Large Hole Screen Polyurethane Strip Separation Screen Polyurethane Rubber Screen Tangshan Polyurethane Screen Factory
Polyurethane Screen The vibrating screen is a vibrating screen with high frequency and high vibration strength. It is mainly suitable for wet classification and solid-liquid separation of fine particles below 0.5mm. In the coal preparation industry, due to its low investment and operating costs, most coal preparation plants have the ability to use their recycled slime to achieve a closed cycle of washing water and improve the environment of the coal preparation plant, with obvious economic and Social benefits. It has been widely promoted and applied at home and abroad.
1 Research status of foreign high-frequency vibrating screens As early as the early 1950s, high-frequency vibrating screens have been developed abroad. In the metallurgical industry, it is used as a fine ore iron ore grading in a concentrator; in coal processing, it is used for dewatering, de-intermediation and grading of coal slime. At present, countries with foreign technology in the United States include the United States, Australia, Germany, France and Finland. Its products are also diversified, such as the SLV type high-frequency vibration dewatering screen produced by Schenck, and the HF type high-frequency vibrating screen produced by Nordberg.
At present, from the literature reviewed, the vibration parameters of the high-frequency vibrating screen designed abroad are very different from each other, and the vibration frequency is 24 to 60 Hz and the vibration intensity is 5 to 11 gn. The high-frequency vibrating screen produced abroad has the advantages of large processing capacity, high efficiency, stable performance and long service life, but the disadvantages are mainly expensive, small processing volume and low cost performance. At present, the span is only 1.8m. Although the models of foreign high-frequency vibrating screens are different, the working principles are basically similar. The following is a brief analysis of the most typical American Derrick high frequency screen, Welkau dewatering screen and SD type high frequency vibrating screen.
111 Derrick high-frequency vibrating fine screen Derrick high-frequency vibrating fine screen was invented by Derrick Company in 1951. The structural principle is shown in Figure 1. Its structural features:
(1) High frequency, low amplitude (60Hz, 0.8mm) is adopted, and the positive inclination angle and the large inclination screen surface (>30°) are adopted, and the screen surface has high transportation capacity.
(2) The sieve machine has three independent sieve faces, which are separately fed, and the treatment capacity is 1.5 times larger than that of the single-point feed sieve while maintaining the same screening efficiency.
(3) The structure of the sieve chute is unique in that it does not hinder the sieve water falling from the middle and the discharge end screen into the sieve water funnel of the sieve machine.
(4) The exciter is mounted on the upper part of the screen box to generate a 60 Hz excitation force. The screen surface is made of wire mesh woven sandwich screen, which has the advantage of being not easily blocked, so it is not necessary to clean it frequently.
Polyurethane Screen 112 Welco Dewatering Screen The Veliko dewatering screen produced by Linnatex Company of the United States has the structural principle shown in Figure 2. Its structural characteristics:
(1) The slurry from the feed tank is fed in an almost vertical direction.
(2) The inclination angle of the screen surface of the feeding end is >45°, the main screen surface is installed at a negative inclination angle, and the entire screen surface is in a V-shaped state.
(3) The front end of the feed end screen surface and the main screen surface adopts a wedge-shaped slit screen surface, and the discharge end end adopts a polyurethane sieve plate, and the sieve joint gradually increases from the feed end to the middle portion to the discharge end.
(4) Two motors are installed on the load-bearing beam of the screen box. Adjust the eccentric weight on the shaft extension of the motor to adjust the amplitude. In addition, the discharge end is provided with a seesaw to adjust the thickness of the material layer on the screen surface. .
113 SD type high frequency vibrating screen The SD type high frequency vibrating screen produced by Conway of the United States has the fastest development and the widest application. At present, this type of high frequency vibrating screen has a minimum width of 0.9 m and a maximum width of 1.8 m. Its main features:
(1) The screen surface is installed at an angle of -5°, the amplitude is 3mm, and the vibration frequency is 1474r/min. Due to the climbing of the material on the screen, the material on the screen has a certain thickness. Therefore, it also acts as a filter, so that the moisture of the material is low and the particle size retained is smaller.
(2) Using a special G-MASTEF shaker or vibration motor, the screen surface is made of polyurethane or stainless steel "target=_blank> stainless steel strip seam.
(3) It can provide a variety of products, the sieve body is simple in structure, convenient in maintenance, long in service life, large in processing capacity and high in efficiency.
2 Research status of high-frequency vibrating screen in China In China, the development of high-frequency vibrating screen technology polyurethane screen is relatively late. Until the end of the 1970s, a small amount of high-frequency vibrating screen was introduced only in the metallurgical system. China's development and testing of high-frequency vibrating screens began in the early 1980s, and its typical research is as follows.
(1): The GPS-900-3 high-frequency vibrating fine screen prototyped by the Metallurgical Minister Sha Mining and Metallurgical Research Institute in 1982 was tested in non-ferrous metal ore and achieved satisfactory results. It began in September 1986. Industrial tests were carried out at Miyun Iron Mine, which has more than doubled the screening and classification efficiency compared with the original curved screen. Later, in the early 1990s, GPS-1400-3 high-frequency vibrating screen was used to conduct industrial tests at the Nanshan Iron Mine Concavation Concentrator of Maanshan Iron and Steel Co., Ltd., and the mathematical model between the high-frequency vibrating screen process parameters was established by computer. The optimal control of the high frequency vibrating screen provides the basis.
(2): In order to meet the needs of slime recovery and fine-grain dewatering and grading, the Tangshan Research Institute of the Coal Research Institute is responsible for the research and design of the GPS-1025 high-frequency vibration dewatering screen, which was selected in 1990 by the Haizhou Mine in Fuxin, Liaoning. The industrial test of the factory shows that the sieve machine has reached the advanced level of similar domestic sieve machines. In 2004, QZK-1833 and QZK-2041 curved screens were successfully developed, and good technical and economic indicators were obtained on site.
(3): In the “Seventh Five-Year†Science and Technology Project of the former Ministry of Coal, the original Pingdingshan Coal Preparation Design and Research Institute in March 1989 designed and designed the first GZ-631 high-frequency test sieve with adjustable amplitude-frequency characteristics. In May 1990, the vibration parameters test and research were completed at the Linxi Coal Preparation Plant, and the relationship between the vibration parameters and the screening process indicators was studied.
At present, high-frequency vibrating screens are widely used in China's coal preparation industry. According to the situation reflected by the market, there are about 100 high-frequency vibration dewatering screens per year, and the economic and social benefits are very significant. Therefore, many large-scale vibrating screen manufacturers in China have also followed the market demand and developed many types of high-frequency vibration dewatering screens. For example, GZ series filter dewatering high frequency screen developed by Beijing Huayu Engineering Co., Ltd. (formerly Pingdingshan Coal Preparation Design Institute); QZK series curved screen, GPS series high frequency screen and DZSM series electromagnetic developed by Tangshan Research Institute of Coal Research Institute Vibration high frequency sieve; TSS series dewatering screen produced by Tangshan Huili Taihang Vibration Machinery Co., Ltd.; GBHS high frequency sieve and BHKS series high frequency slime dewatering screen produced by Jiangsu Bohou Coal Preparation Machinery Co., Ltd.; Shanxi Saide Screen The GPS series high-frequency vibration dewatering screen and GZ series high-frequency screen produced by Technology Equipment Co., Ltd. make the domestic high-frequency vibrating screen market more fierce. Although the models are different from each other, the principles are basically the same. In general, the GPS-type high-frequency linear vibrating screen, QZK series curved screen and DZS high-frequency vibrating electromagnetic fine screen have been developed in China. The following is a brief introduction to their respective structural features.
211 GPS series high frequency circular vibrating screen GPS series high frequency circular vibrating screen polyurethane screen, mainly used for the recovery of fine coal slurry, working at 50~60Hz frequency, (1) the sieve machine is carried out in the thin layer and Precision screening is divided into basic slime screening and grading equipment.
(2) Working according to the principle of a circular vibrating screen, having a high frequency of 33.3 Hz and a vibration intensity of more than 5 gn.
(3) The composite screen surface of the “sandwich†screen on the screen surface has an opening ratio of up to 36%, and the anti-blocking effect is very good.
212 GZ, GZT type high frequency linear vibrating screen high frequency linear vibrating screen is divided into GZ type high frequency vibrating screen and GZT type low noise high frequency vibrating screen. The difference between the two is that GZ type high frequency vibrating screen vibrator is a unit combination. The screen frame is an integral welded structure, and the vibrator of the GZT type low-noise high-frequency vibrating screen is a box type, and the screen frame adopts a sandwich type side wall and a beam to reduce noise, and the common features are as follows:
(1) According to the principle of self-synchronization, the vibrator is driven by two motors separately, and there is no forced connection between the two transmission shafts.
(2) The screen surface is composed of an arc segment and a straight line segment with a negative inclination. The slit of the arc segment is perpendicular to the direction of movement of the material, and the noodle seam of the main sieve is in the same direction as the movement.
213 QZK series curved screen The basic principle of QZK series curved screen is similar to GZ type, but the screen surface overcomes the shortcomings of GZ type. The screen surface is generally made of stainless steel "target=_blank> stainless steel step welded sieve plate or composite sieve plate.
At present, the technology develops fastest. This type of sieve machine adopts an operating frequency of 24 Hz, an amplitude of 2 to 2.5 mm, and a vibration intensity of 5 to 7 gn. It has a low moisture content (≤24%) on the sieve material, a large processing capacity and a solid recovery rate. Higher advantage. In recent years, with the successive construction of large coal preparation plants, the specifications of QZK series curved screens have been continuously innovated. At present, QZK-2041 is the largest model for domestic application, and the maximum span of such sieves has reached 2.4. m, the length is 4.5m, which is the world's largest span of high frequency dewatering screen. This type of sieve machine adopts a block eccentric vibrator and a grease-lubricated structure, and its disadvantages are mainly that the lower limit of the screening is limited, and the processing capacity per unit area is low.
3 Development trend of high-frequency vibrating screen at home and abroad (1) Development towards large-scale development. The large-scale vibrating screen refers to the large-scale movement parameters and area of ​​the sieve. It mainly solves the problem of the screening effect of the material and the processing capacity of the sieve. The large-scale can reduce the number and cost of the screening equipment and reduce the plant. Area, reduce initial infrastructure investment.
(2) To reduce the development of vibration quality. By reducing the mass of the vibration, the exciting force can also be reduced, thereby ensuring strength and rigidity, reducing vibration noise, and providing good vibration damping.
(3) Development towards standardization, serialization, and generalization. Standardization, serialization, and generalization are effective ways to design, produce, and reduce costs.
(4) Analysis and research on the use of high frequency vibrating screen in coal preparation. At present, the high-frequency vibrating screen replaces the sedimentation filter centrifuge, the pressure filter or the diaphragm filter to perform dewatering of the flotation clean coal, instead of the flotation system and the recovery group coal slurry, and the practice in the coal washing plant has achieved good results. In the future, it will analyze and research its other uses in coal preparation to improve its role in coal preparation.
4 Problems in China's high-frequency vibrating screen Polyurethane screen (1) The structure of the screen machine itself is not well understood. In the design process, due to insufficient understanding of the structural strength of each component, stress concentration is likely to occur in production, which causes breakage of side plates, support beams, sieve plates, etc., which affects normal production activities.
(2) Progress is slow in the process of designing large-scale. At present, the largest model for successful domestic application is the QZK-2041 curved screen, the GFS-2445 curved screen under study, but due to insufficient understanding of the structure, it is still in a less mature stage.
(3) The relationship between the technical parameters of the high-frequency vibrating screen is not well understood. Due to insufficient understanding of the relationship between various process parameters or vibration parameters of the high-frequency vibrating screen, mistakes in design or selection are prone to occur, resulting in phenomena such as “running water†and “running roughâ€, which may affect normal production.
(4) The structural strength of the material cannot meet the requirements. At present, there are still many gaps in domestic research on materials compared with foreign countries, which makes the life of domestic high-frequency vibrating screens generally low. The current life expectancy is generally 3 to 5a, while that of foreign countries is about 8a, resulting in increased production costs and resources. waste.
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