Seven factors affect the output of metal hammer crusher
Time:2021-09-06
Metal hammer crusher Video:
What are the factors that affect the output of metal crusher 1. Feeder
There are many kinds of feeder, such as spiral, vibration, gate, impeller groove, belt and so on. The key of feeder selection lies in the stability of feeding and adaptability to crushed materials. The feeder must be able to feed evenly along the entire length of the population of the crusher and to feed at an even rate. Uneven feeding will cause unstable working state and uneven wear, resulting in lower productivity and poor grinding quality. In comparison, spiral feeders are not the best choice. The impeller slot feeder has many staggered grooves on the rotor, feeding is more uniform, and can be fed along the whole length of the population of the crusher, currently in use more.
2. Linear speed of hammer
The hammer linear speed depends on the diameter and speed of the mill rotor, usually the higher the speed, the finer the crushing particle size, in a certain range to improve the hammer linear speed can improve the crushing efficiency. The hammer linear speed of the domestic mill is usually about to 86 m/s, and that of micro mill is about 93 m/s.
3. hammer screen clearance
The hammer screen gap is the short distance between the hammer and the sieve plate. Material crushing in the mill can be roughly divided into two zones: acceleration zone and full speed zone. The acceleration area is mainly crushed, and the full speed area is mainly grinding. In the acceleration area, the material just entered and the circulating material not screened is accelerated under the impact of the hammer. Due to the relative speed between the hammer and the material, the material (especially brittle materials, such as corn, sorghum, etc.) is easy to be crushed. Material through the acceleration zone, the speed gradually reached peak and stabilized, the relative speed of the material and the hammer is small, the impact force becomes smaller, the crushing of the material is mainly friction with the sieve plate. When the finished product requires coarser particle size, the acceleration zone can be used as the main crushing zone, and the larger hammer screen gap can be selected; If the finished product requires fine particle size, the full speed zone can be used as the main crushing zone, and the hammer screen gap is smaller.
4. auxiliary suction
When the crusher works, the material in the machine will form a circulation layer under the action of the rotation of the hammer. The material moves together with the hammer, and the relative speed of the hammer is small, the hammer strike force is small, the discharge speed is slow, causing a lot of waste of power. In the hammer screen gap is larger, this situation is more serious, because at this time the thickness of the material layer, the shear effect between the material layer is small, close to the screen surface of the material layer speed is slow, small particles out of the screen, leaving large particles *** in the screen surface, more hinder the discharge, and the formation of excessive crushing of inner material. At the same time, the circulation layer will also obstruct material feeding. After a period of shattered, excessive crush the material inside the machine through the sieve plate quickly, cause the loss of host current suddenly, feeding with the sudden increase, cause a large crushing process fluctuations, intermittent discharge, hammer above the working face, hammer frame plate and pin shaft wear serious, finished product size distribution is not uniform, fine powder, and coarse. After adding appropriate auxiliary suction, the pulverized material is sucked out of the screen in time, which also plays a certain role in hindering the formation of circulation layer. For the sieve plate with ∮3mm sieve hole, the teaching rate can be increased by more than 20%, and with the decrease of sieve hole, the efficiency is improved more obviously. At this time, the host working current is stable, and wear mainly appears in the working face of the hammer, hammer frame plate, pin shaft and other basic no wear.
5. Secondary crushing chamber
Material in the acceleration zone crushing effect is more obvious, after the acceleration zone of the large particle material in the machine cycle for a week after entering the acceleration zone for crushing. At present, the new type of crusher such as Muyang Shuiwang 968, Muyang Xianfeng 668 and so on are designed in the lower part of the crushing chamber “W” or “U” type of secondary crushing chamber, material flow through the secondary crushing chamber colliding with it, the direction of movement changes, and the relative speed of the hammer increases C, so in this area and the formation of an acceleration zone, crushing large particles. In addition, the material flow is re-stratified here, and the circulation layer is weakened, which is conducive to discharging and improving efficiency.
6. hammer 6.1 Layout of hammer plates
The hammer is generally arranged symmetrically, and the corresponding two groups of hammer are installed symmetrically, so the force of the two pins on the rotor can be balanced each other, the rotor runs smoothly, the material distribution is uniform in the crushing room, and all the hammer wear is synchronous. At the same time, this arrangement requires less types of bushing, hammer installation is simple and convenient.
When the hammer passes through the screen surface, it drives the surrounding material flow to move in the same direction. If the number of hammer increases in the axial direction of the rotor, the driving effect on the material flow will be enhanced. Therefore, when carrying out fine crushing, increasing the number of hammer in the axial direction will improve the crushing efficiency in the full speed zone.
Coarse crushing, full speed area is mainly used for screening, because the material layer is thick, with continuous screening, large particles will *** in the screen surface, block the discharge, and the formation of excessive crushing of inner material, waste power. If some lengthened hammer is added in the hammer layout to flip the material layer on the screen surface, the screening capacity will be enhanced and the crushing efficiency will be improved.
6.2 Wear of hammer
In the acceleration zone, coarse crushing is the main process, while in the full speed zone, fine grinding is the main process. In the acceleration zone, the main working face of the hammer is side, so the material or surfacing layer on the side is required to have high toughness and impact resistance; In the full speed zone, the main working surface of the hammer is the end face, so the material or surfacing layer of the end face is required to have high hardness and wear resistance. In fact, the hammer is a kind of comprehensive wear, the coarse crushing hammer, the requirements of its side is higher than the end, the fine crushing hammer, the requirements of its end is higher than the side, so that the reasonable uniform wear of the hammer can be guaranteed.
7. sieve plate 7.1 Opening rate of sieve plate
The opening rate of the sieve plate refers to the percentage of the total area of the sieve plate to the entire screen surface area. The opening rate of the standard sieve plate is calculated by 90.7D2 / T2 (%), and D is the diameter of the sieve. T is hole spacing. The higher the opening rate of the sieve plate, the greater the production capacity of the crusher. The main factors restricting the increase of opening rate are punching technology and sieve plate strength. Generally speaking, the opening rate of sieve plate ∮1.2mm and above is shown in Table 1.
If the opening rate is lower than the above value, the production capacity of the crusher will be affected and the material will be crushed excessively. Sieve plate below ∮ 1.2mm when the opening rate, the strength is not enough, stainless steel sieve plate can be used to improve the service life.
7.2 Arrangement of sieve holes on the screen
There are two ways to arrange the mesh with respect to the rotation direction of the rotor. One is that the hole spacing is parallel to the rotation direction, called a-direction; One is the hole spacing perpendicular to the direction of rotation, called the B direction. A to the sieve plate mesh arrangement is easy to process, but the mesh spacing is arranged, the screening effect is poor; B to the screen plate sieve layout hole opening rate uniform. Under the same condition, the yield of b-direction sieve plate is increased by 0% ~ 30% than that of A-direction sieve plate.
7.3 Wear of sieve plate
When the screen plate is worn, the edge of the sieve hole becomes blunt, and the screening capacity will decrease. Because the sharp edge of the screen hole plays a role of collision and friction with materials, and prevent materials from crossing the screen hole. When the edge of the screen becomes dull, the material is easy to slip through the screen. Therefore, the new sieve plate should be installed toward the rotor hair surface, which is conducive to discharging. And pay attention to change the direction of the rotor, the use of another sharp edge of the screen, maintain the original production capacity. When both sharp edges are blunt, the screen plate can be turned over, so as to make full use of the screen plate and not affect the production efficiency. For the smaller the size of the screen, the sharp edge of the screen has a more obvious effect on the screening capacity. The new sieve plate with screen holes of ∮1.0mm will yield about 50% more than the old sieve plate with sharp edge wear.
In order to increase the service life of the screen plate, it is usually necessary to carburize, nitride and other heat treatment to improve the hardness of the screen plate.
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