As the name suggests, the impact crusher uses the counter force to achieve the crushing effect. After the bulk material enters the crushing chamber between the counterplate and the rotor, the kinetic energy is obtained by the rotation of the rotor part, and it is repeated between the counterplate and the rotor. The impact is successively crushed by the first-stage counter-attack chamber, the second-stage counter-attack chamber and the bottom grinding chamber to achieve the required discharge granularity. Second, the technical advantage of the impact crusher compared to the hammer crusher 1. It can effectively treat materials with large moisture content and prevent clogging of crusher When the moisture content of the treated material is too large, the feed chute and the counterplate of the impact crusher may be equipped with a heating device to prevent the material from sticking. The impact crusher does not need to be equipped with a bottom sieve plate to prevent clogging. The hammer crusher cannot be heated to prevent the material from sticking, and the bottom sieve plate must be provided to increase the possibility of blockage. 2. Counter crusher is suitable for both soft materials and very hard materials. The hammer of the impact crusher is fixed to the rotor by a mechanical clamping structure, and has a large moment of inertia when it rotates with the rotor. Compared with the hammer crusher (the hammer is in a suspended state), the rotor of the impact crusher has greater momentum, adapts to crushing harder materials, and consumes less energy. 3. It is convenient and flexible to adjust the discharge granularity and wide adjustment range. The impact crusher can adjust the discharge particle size in a variety of ways, such as adjusting the rotor speed, adjusting the backlash and the clearance of the grinding chamber. The gap adjustment can be adjusted mechanically or hydraulically, and the hydraulic adjustment system can be used to easily adjust the gap through the local operation button or the travel control system. The hammer crusher can adjust the discharge particle size only by replacing the bottom sieve plate. 4. The wearing parts wear is smaller than the hammer crusher, high metal utilization The wear of the counter crusher plate hammer is only present on the side facing the material. When the rotor speed is normal, the feed will fall to the surface of the hammer (the striking surface), and the back and sides of the hammer will not be worn. Even the wear on the side of the material is scarce. And the bottom grinding rod is also easy to replace. The metal utilization rate of the impact crusher plate hammer can be as high as 45% - 48%. The hammer crusher hammer is in a suspended state, and the wear occurs on the upper, the front, the rear and the side. Compared with the hammer, the hammer wear is more serious, and the metal utilization rate of the hammer is only about 25%. Moreover, the rotor body itself may also be subject to wear. The bottom sieve plate of the hammer crusher is seriously affected by the wear, the barrier is completely replaced, and the work of replacing the sieve plate is also complicated. 5. Easy replacement of spare parts and corresponding reduction of maintenance costs Only 6 hammers are installed on the rotor of the impact crusher. It is convenient to replace the hammer with the special tools provided. It takes only one shift to replace the set of hammers. The replacement of the bottom grinding chamber grinding rod can also take only tens of minutes, which greatly reduces the time and cost of inspection and maintenance. The hammer crusher has more than 100 hammers. It takes a lot of time and manpower to replace a set of hammers, and the maintenance and maintenance costs are high. The replacement of the bottom screen is also extremely troublesome.
At present, the five most commonly used thermosetting plastics in various fields are PU, epoxy resin (EP), silicone, unsaturated polyester (UP) and phenolic resin (PF).
Thermosetting plastic has the following advantages:
Thermosetting plastic has a large rigidity and is extremely elastic and plastic deformation.The temperature has little influence on stiffness, and under the same load and temperature, the creep variable is much smaller than thermoplastic.Good heat resistance;The plastic parts are quite stable when heated.The size of the plastic parts is good. Thermosetting plastic is less affected by temperature and humidity, and Thermosetting plastic can be reduced after forming, making Thermosetting plastic easy to make plastic parts with high precision than thermoplastic ruler.Excellent electrical performance.Resistance to arc and voltage, etc.Good corrosion resistance, weak acid, weak base and organic solvents;Good processability, can be processed by various molding methods and other advantages.
Most thermosetting plastics have the following characteristics:
(1) excellent chemical resistance.
(2) it is usually brittle hard plastic, which can be filled with various fillers to form composite materials.
(3) compared with thermoplastic resin, the molding cycle is longer.
(4) all kinds of modification can be carried out, depending on the combination of resin, crosslinking agent, additive, etc., which can form composite materials with different properties.
(5) good heat resistance, the use of high temperature, Tg of thermosetting polyimide (PI) is about 350 ℃.
(6) can be used as raw materials to meet the application of various fields.Only 5% is used as injection molding material.
(7) the waste is generally used as filler after pulverization, which is difficult to recycle and pollutes the environment.
Due to the high heat resistance of thermosetting plastic, good dimensional stability, good line performance, anti-aging properties are better than thermoplastic plastic and low price, so it is widely used.The disadvantage is that the mechanical properties are poor and need to be enhanced.
It is mainly composed of thermosetting resins, which are involved in various necessary additives to form the plastic of the products.In the process of manufacturing or forming, the liquid will be liquid, which will not melt after curing or melt or soften again.Common thermosetting plastics include phenolic plastic, epoxy plastic, amino plastic, unsaturated polyester, alkyd plastics, etc.Thermosetting plastic and thermoplastic plastics constitute two major components of synthetic plastic.
Thermosetting plastic heating for the first time can soften the flow, heated to a certain temperature, react a crosslinking reaction and curing hardens, this change is irreversible, since then, heating again, already no longer soft flow.It is the use of this characteristic to make the molding process, using the plasticization flow of the initial heating, filling the cavity under pressure, and solidifying to become the product that determines the shape and size.
Thermosetting plastic is distinguished by a chemical reaction that is hardened by heating, pressing or adding the hardener at a definite temperature.After hardening, plastic chemical structure changes, the texture is hard, dissolves in the solvent, heating also no longer softens, if the temperature is too high then decompose.In thermoplastic plastic, the chains of resin molecules are linear or branched, and there is not any chemical bond between the molecular chains, which soften the flow when heated.The process of cooling and hardening is a physical change.
Formaldehyde cross linked plastic includes phenolic plastic, amino plastic (such as urea-formaldehyde - melamine - formaldehyde, etc.).Other cross linked types of plastic include unsaturated polyester, epoxy resin, prevalence, diallyl ester resin, etc.
The commonly used thermosetting plastics are phenolic resin, urea-formaldehyde resin, melamine resin, unsaturated polyester resin, epoxy resin, silicone resin, polyurethane, etc.
Production:Phenolic resin PF (Bakelite sheet)
Phenolic resin is a part of the longest plastic varieties in history, commonly known as bakelite or electric wood, and the appearance is yellowish or black, which is the typical representative of thermosetting plastic.Bakelite sheet molding often use a variety of filling materials, according to different filling materials used, the product performance is also different, Bakelite sheet as molding material, mainly used in the field of need heat resistance, but also as a bonding agent used in plywood, grinding wheel and the brake pads.
Thermosetting Plastic,Thermoset Molding Plastic,Mould Thermosetting Plastic,Thermoplastic Type Plastic Dongguan Noegem Plastic Products Co.,Ltd , https://www.noegempLastic.com
First, the working principle of the impact crusher