The impact crusher is a equipment for crushing the medium hardness material with impact energy. It is widely used in cement, power, building materials, chemical industry, coal and metallurgy industries. The impact crusher has the advantages of large crushing ratio, uniform particle size, less smashing phenomenon, low energy consumption, easy manufacture, easy maintenance, large granularity adjustment range and selective crushing etc. The impact crusher is divided into two main categories, single rotor and double rotors. The classification of the crusher is described in Figure 1. The specification method of the impact crusher is expressed by the rotor diameter D and the rotor length L.
Figure1. The classification of impact crusher
2.Working principle of impact crusher
The impact crusher is crushing by using a high-speed rotary hammer to impact the ore. Figure 2 is a schematic diagram of the working principle of a impact crusher. When the hammer impacted the ore into the crushing chamber is very high speed rotation and selective crushing. The ore obtained tremendous kinetic energy from the impact process, and high speed into the first stage back plate, because the attack role impact plate, the ore was again crushed by impact plate bounce back again by ore hammer impact, continue to repeat the process of breaking. After that, the crusher ore is also thrown into the second stage impact plate at high speed, which is further crushed. As a result, the ore is fractured, loosely and fractured along its joint surface through the repeated impact of hammer and impact plate and the collision between ores. When the grain size is less than the gap between the hammer and the impact plate, it is discharged from the lower part of the machine into a qualified product.
Figure2. Working principle chematic diagram of impact crusher
1 rotor; 2 hammer; 3 pull rod; 4 secondary impact plate; 5 primary impact plate; 6 chain; 7 feeding port; 8 frame.
3.Structure of impact crusher
The impact crusher is divided into two types, single rotor and double rotor, according to the different number of rotor. Figure 3 is a 1250x1000 single rotor impact crusher produced by Sinonine. The structure of the crusher is simple, which is mainly composed of frame, transmission mechanism, rotor, hammer and impact plate.
Figure 3. 1250x1000 impact crusher
1 Frame; 2 whole plate; 3 rotor; 4 strike plate; 5 screen plate; 6 Primary impact plate;7 secondary impact plate; 8 maintenance door; 9 spring adjustment part; 10 pulley; 11 motor.
The frame of the impact crusher consists of two parts of the upper frame and the lower frame, which are bolted to each other. The upper frame of the axis of the rotor is mounted on the upper frame, with a side door and a rear door for maintenance and installation. Under the axis of the rotor, the bottom is the lower frame, which is fixed on the foundation with the bolt, which mainly bears the weight of the whole machine. All the parts of the contact ore inside the frame are fitted with replaceable wear-resistant liners. A chain curtain is set at the feeding port of the crusher to prevent accidents occurring outside the machine during the crushing process.
3.2. Transmission mechanism
The transmission mechanism of the impact crusher is quite simple, and the motor can rotate the spindle and the rotor at a high speed through the pulley. The spindle is supported in the bearing seats on both sides of the frame by rolling bearings, and the bearings are usually lubricated by dry oil.
The hammer and rotor of the impact crusher are rigid connections, which break through the rotary inertia of the whole rotor to impact the ore. The rotor must have enough quality to meet the requirements of the crushed ore. If the mass of the rotor is too light, the crushing efficiency will be reduced. The rotor can not be too heavy, or the crusher will be very difficult to start.
The rotor of the impact crusher usually adopts the integral cast steel structure. The structure is of large quality, which is easy to meet the mass energy required by the crusher, and at the same time, it is also sturdy and durable, so that it is easy to install hammer head. Some of the counter crushers are made of disks made of pieces of cast steel or type steel. The combined rotor is easy to make and is easy to balance.
3.4. impact plate
The impact plates are made of high manganese steel or other wear-resistant materials, hang freely inside the machine. One end is articulated on both sides of the upper frame through a suspension shaft, and the other end is supported on the conical washer of the upper frame by a rod bolt. The impact plate is also an insurance device for the crusher at the same time. When entering the non crushing material, the impact by the rapid increase in the back plate, forcing the bolt compression spherical washer, the bolt back up, let the non breaking materail discharge, guarantee the safety of machine. In addition, the adjustment of the nut on the rod bolt can change the size of the gap between the hammer and the impact plate, so as to control the size of the crushed product. As the impact plate is directly involved in the breakage, the shape and structure of the impact plate have a greater impact on the crushing efficiency. In order to obtain the best crushing effect, the material and the surface of the impact plate should be collided vertically. At present, impact crusher impact plate machine generally made of folded or involute, the former has the advantages of simple structure, easy processing, but can not meet the requirements of the best ore crushing effect; the latter in the back plate each point on material in the vertical direction of the impact, so can obtain optimum crushing effect, but due to the processing difficult, the general use of approximate involute impact plate with multi section arc composition.
The hammer of a impact crusher is also made of high manganese steel or other wear-resistant material, fixed to the rotor. In general, there are 3 kinds of fixed methods.
1）Screw fixation. Fix the hammer with screws. This method is the simplest, but the screws are easily damaged on the surface, and the screws are also easily cut off, causing the hammer to fly out of the rotor and cause serious accidents.
2）Press plate fixation. The hammerhead is inserted in the groove of the rotor from the side, and the two ends are pressed to prevent its left and right movements. This method, because the hammer is made of wear-resistant material, is difficult to manufacture, difficult to ensure the precise size of the hammer, easy to be easy to assemble and loose in work.
3）Wedge fixation. Use a wedge to fix the hammer on the rotor. In the work, because of the effect of centrifugal force, the hammer , wedge and rotor will become more and more tight, the work is more reliable, and the disassembly is also very convenient. This fixed method is more applied
The number of hammers is related to the rotor diameter D. Usually, when D< lm is applied, 3 hammers can be selected. When D = 1-1.5m, 4-6 hammers can be selected; when D = l.5-2m, 6-10 hammers can be selected. In addition, when the ore is harder to crush, the number of the hammer can be increased. The shape of the hammer is much more. At present, it is used more as shown in Figure 4.
Figure4. he shape of the hammer
1. long strip shape; 2.I shape; 3.T shape; 4.S shape; 5. axe shape
4.double rotor impact crusher
The double rotor impact crusher has two rotors, and the 1250x1250 double rotor impact crusher is introduced as an example (Figure 5). The two rotor of the crusher is rotating in the same direction, and the two rotors are parallel arranged and have a certain height difference. It is equivalent to two single rotor impact crusher used in series. The first rotor is equivalent to coarse crushing, and the second rotor is equivalent to fine crushing. The two rotors are equipped with a different number of hammers, and the height and shape of the hammer are different, and the speed of the two rotors is different. The first rotor has 4 rows of 8 hammers, the speed is 38m/s, and the second rotors have 6 rows of 12 hammers, and the line speed is about 50m/s.
Figure 5. 1250x1250 double rotor impact crusher
1. Frame, 2. first stage rotor, 3. first impact plate, 4. counter cavity impact plate, 5. second stage rotor, 6. second impact plate, 7. adjusting spring,
8. second grid plate, 9.first grid plate.
The two rotors of the crushe are rotated in the same direction by two motors, which are composed of the elastic coupling, the hydraulic coupling and the trapezoid V belt. The first stage rotor of -850mm ore crushed to about -100mm and then enter the second stage crushing chamber, the two stage rotor will continue crushing the ore to -20mm and then discharge prodct from bottom.
5.Specification of impact crusher
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It has a big feed opening and a high crushing chamber. Materials of high hardness and big size can be crushed by it, and the product is of less powder.
The space between the impact plate and the blow bar can be adjusted conveniently. The particle size is controled effe ctively. The product is of good shape.
It has a compact structure and can resist strong forces. Its totor has a great rotational inertia.
Chrome hammer is used and can bear impacts, abrading and can impact with a great force.
The no- board connection makes it easy to repaire and maintain.
It has more crushing functions and is of bigger productivity, less wearing, higher comprehensive benefits.
This impact crusher consists of main frame, rotor, front blow bar and back blow bar. Each gyrating cycle is formed by V-belt driving rotor through electronic and materials are crushed by high speed impact of flat hammer on gyrating rotor. After that, the materials are crushed again by throwing impact liner and then crushed again from impact plate to flat hammer. This process works again and again until materials being qualified size.
Any change of technical parameters, there is no further notice.