Domestic scholars talk about the development of screening machines, which must be discussed in large-scale, attracting attention from all parties. Enterprises even spend huge sums of money to introduce foreign large-scale screening machine technology. Now it seems that some introductions have failed, and it is not necessary. It is obvious that the waters are not satisfied. Need to talk about the reliability of large screen machines and the factors affecting reliability. Therefore, the direction of large-scale must be accurate. (1) The hardware is better than the German KHD company, Schenck company, American Tabor company, and the United States Conn Weld company has developed rapidly with its solid foundation work. The screening machine adopts CAD for finite element structure and dynamic analysis. It has the first-class equipment testing and inspection in the United States. The cutting material is made of high-pressure water cutting machine, manufactured by CNC machine tool, assembled in high-standard working room, and finally treated by shot peening and painting. Its products have basically improved the structure and technology of Allis and Tabor in the United States for decades, but the equal-thickness screen is 39 m2, linear screen. Domestic units want to spend money to buy people's drawings, when introducing technology to achieve 27 m2, pay attention to it, know that its products are good, but also know that its hardware foundation is good. (2) The structure should be simple and the reliability is high The screening machines used by several large foreign screen manufacturing companies in special fields have been studied deeply. In terms of large-scale, the structure and technology have remained basically unchanged. The three-channel large-scale screen developed by KHD of Germany has not developed, and its largest screening machine USL 4.5 m ?.75m structure has not changed, using self-synchronization technology, the world's largest sieve machine is Germany's Sieb Technik's 50 m2, 5.5 m wide single-layer linear screen, and Schenck's largest product single-layer linear screen width 4m, length 8.5 The structure of m is basically the same, except that the former uses four small box-type exciters, and the latter uses two large-point box exciters. In addition, the largest HLW type (width 4.8 m, length 7.1 m) of the Kobe Steel Works in Japan was also constructed using the American Low Head type exciter, and later changed to a horizontally placed exciter. The largest screen machine of Tabor in the United States is a single-layer linear screen of 3.7 m?.3 m. The structure is unchanged, but only three box exciters are used. However, there are many domestic patterns, and the structure is changing. Some large-scale and even deviate from the development direction. It is possible to produce a large flat rice sieve machine by combining several 2 m? m small sieve machines. The large-scale 3073 double-layer circular sieves all use double exciters, but the structure is very different, and the 2 sieves are miniaturized. Many domestic projects require 1~3 m advanced screening machines, and few people develop and research. The fine polyester screen (below 0.5 mm) has a very low manufacturing level, and even the direction of the linear screen vibration motor that has been rarely seen abroad is almost always used in China, which is unreasonable. The screen machine produced by Derrick is used in Guangxi Longtan Hydropower Station is the world's most advanced small screen machine. It is equipped with double long tube vibration motor placed up and down. The screen body is mounted by shear rubber spring suspension, in order to closely match the screen surface arc shape. The high-performance adhesive is used to fasten the sieve body into a curved shape, and the seal is good everywhere, and the sieve is not leaked. The sieve surface has reached the precise sieve hole, the opening rate is 45%, and the dehydration efficiency can reach over 90%. 3 oval sieve Foreign three-axis elliptical screens have developed rapidly (JCI, Cedarapids, Gator) with the following structural features: (1) Bearing outer ring rotation (In addition to the inner ring rotation), the outer ring rotation centrifugal force is larger than the inner ring rotation, and the inner ring rotation centrifugal force action area (1/3 of the inner ring) is generally prone to particle spalling fatigue damage, and The outer ring rotates the centrifugal force to have a large area and the bearing has a long service life; (2) The intermediate drive shaft is small. For example, Cedarapids' 2.1 m?.0 m elliptical sieve intermediate shaft is only 70 mm. Why is it so small because it is not subjected to centrifugal force and only transmits the torque from the motor to the opposite eccentric block; (3) Small opening on the side panel (Unlike the side panels of the Kobe Steel Works in Japan, which have such a large opening), this has little effect on the strength and rigidity of the screen. The bearing is forced on the outer side of the side plate, the intermediate transmission shaft is small, and the intermediate shaft cover body can be impacted by the upper layer material and can strengthen the rigidity of the sieve machine; (4) It is easy to maintain by using the popular expansion sleeve (pulley pulley) and the taper sleeve (bearing); (5) The adjustable diameter pulley of the pulley makes it easy to change the excitation frequency. High screening efficiency, horizontal installation, suitable for mobile crushing and screening units. Domestic elliptical screen develops very fast, there is a copy of the above structure (ZST type), there are three axes, the synchronizer does not participate in vibration (our company's STDL type cold mine screen), there are also two-axis self-synchronization (our company DTS type equal thickness Elliptical sieve) and forced synchronization (type 2TYA). Synchronizers are used less abroad, and domestic ones are more enthusiastic.
Graphite electrode, mainly in petroleum coke, needle coke as raw material, coal tar pitch as a binder, calcined, ingredients, mixed kneading, pressure, roasting, graphitization, machining and made in the arc furnace in the form of arc The energy can be divided into Ordinary Power Graphite Electrode, High Power Graphite Electrode and Ultra High Power Graphite Electrode according to its quality index.
Graphite electrode transport
1, graphite electrode in the long-distance transport to be covered with anti-rain Pengbu.
2, with lifting machinery unloading wooden box packaging electrodes, you must use the wire rope, not directly hook the electrode steel packing belt for lifting.
3, in order to protect the electrode end and thread, not directly with hook hook electrode hole hanging electrode.
4, loading and unloading joints box, you should gently take to prevent damage to the thread.
Second, the graphite electrode storage
1, the electrode should be stored in a clean, dry place; temporarily do not use the electrode and connector, do not remove the packaging, to prevent dust, debris fall into the thread or electrode hole, affecting product docking accuracy.
2, open field stacking electrodes, must be covered with rain pants. In the case of
3, the electrode in the Treasury storage to be placed neatly, the electrode stack on both sides to pad well, to prevent the cartoons.
4, bulk electrode stacking height is usually not more than 2.8 meters, the height of the box electrode should not be more than 4 layers.
5, the temperature of the place where the joints should be stored should not be too high to prevent the asphaltene joint bolt melting.
Third, the graphite electrode connection operation
1, by the wet electrode, before use to dry.
2, remove the spare electrode hole on the foam protective cap, check the electrode hole thread is complete.
3, with no oil and water compressed air cleaning spare electrode surface and hole thread; to avoid the use of wire or metal brush cloth cleaning.
4. Do not touch the threads in the electrode holes where the joint is carefully screwed into one end of the backup electrode (it is not recommended to insert the connector directly into the electrode that is replaced on the furnace).
5, the electrode spreader (recommended the use of graphite material spreader) screw into the other side of the electrode electrode electrode hole.
6, lifting the electrode, the mat soft objects to the bottom of the alternate electrode assembly to prevent the ground to break the joints; with a hook into the spreader after the lifting ring, lifting the electrode to be smooth, to prevent the electrode from the B-loose Off or collide with other fixtures.
7, the spare electrode hanging to the top of the electrode to be connected to the electrode hole slowly after the fall; rotating the backup electrode, so that the screw hook and the electrode with the rotation down; in the two electrode end distance 10-20mm, again with compressed air Clean the two ends of the electrode and the exposed parts of the joint; in the final complete discharge of the electrode, not too much, or because of violent collision, will lead to electrode holes and joints of the thread damage.
8. Tighten the backup electrode with a torque wrench until the ends of the two electrodes are in close contact (the correct connection of the electrode and the connector is less than 0.05 mm).
Fourth, the graphite electrode in the use of the precautions
1, the electrode holder should be caught in the top of the cord outside the cordon, otherwise easily lead to electrode break. The contact surface of the gripper and the electrode should always be cleaned to maintain good contact with the electrode, and the gripper cooling water jacket should be kept leaking. In the case of
2, the electrode connection found cracks exist to identify the cause, to eliminate the gap before use.
3, connecting the electrode, found that the phenomenon of joint peeling off, to fill the joints and then connect the bolt.
4, the electrode should be used vertically, to avoid tilting operation, in particular, can not be connected to a group of electrodes placed horizontally, so as not to break.
5, to the furnace into the charge, the bulk material should be installed near the bottom of the furnace to reduce the collapse of the large pieces of charge impact electrode.
6, smelting, should avoid a large number of insulation material stacked in the electrode just below, so as not to affect the use of electrodes, or even electrode break.
7, the electrode in the rise or fall, should avoid touching the lid, resulting in electrode damage.
· 8, in the smelting site, to avoid slag splashing to the site of the electrode or connector threaded buckle, damage the thread accuracy.
Graphite Electrode,Discharge Graphite,Graphene Battery,Carbon Graphite Electrode Fengcheng Ruixing Carbon Products Co., Ltd , https://www.lnfcrxts.com
Technical problems faced in vibrating screen design and production
1 Screen machine large-scale problem