Discussion on adaptability of high precision plate feeding scale in cement production processDate: 2019-06-25 Views:
In the production process of the modern cement industry, the ingredients of raw material grinding and cement grinding are related to the stability of the raw material into the kiln and the quality of the finished cement. The selection of the batching scale plays a vital role in the process status, operation process control, cost control, product quality and operation rate of the entire cement plant production process.
I. Current status of solid material batching technology in cement industry
Tape type quantitative feeders are widely used in the continuous transportation and dynamic weighing control of production processes in cement, metallurgy, mining, electric power, chemical, coal, food, food and other industrial fields. However, for some large diameter material reservoirs (eg limestone, clinker, sandstone, aggregate, ore, etc.) and less fluid material reservoirs (eg clay, sulfuric acid slag, desulfurized gypsum, phosphogypsum, raw coal) In the case of carbide slag, laterite nickel ore, etc., due to the characteristics of the materials and the requirements of the production process, the discharge opening at the bottom of the silo must be designed with a larger opening size to meet the requirements of high-flow materials, high-humidity and high-viscosity materials. Production requirements. This large material port has a large pressure on the lower conveying equipment while satisfying the unloading of the material. The ordinary tape type quantitative feeder can not bear the demand of the material under the pressure of the large warehouse, and usually needs to be increased at the bottom of the warehouse. As a pre-feeding equipment, a board feeding machine first pulls the material out of the bottom of the library and enters a small intermediate hopper. The lower stage adds another metering machine to measure, and the two-stage equipment interlock control completes the quantitative feeding and metering. Requirements.
Because the plate feeder and the tape type dosing machine must be installed on different installation platforms, the height of the installation space of the two devices is relatively high, and the investment in equipment investment and material construction is also large.
Since the normal working state of the plate feeding machine is high material layer low speed feeding, the control flow rate of the tape type quantitative feeder is usually adjusted in real time, which often causes the material in the middle feeding hopper of the plate feeding machine to the dosing machine to be more or more. Or less, easy to cause blockage or breakage of materials, and some units even set up individual posts for guards, which is the blocking point and difficulty point of continuous production process control.
For the status quo of the higher temperature cement clinker, it is generally used to assemble a high temperature belt on the dosing machine to adapt to the scalding and carbonization of the ring tape by the high temperature clinker. However, the elongation, carbonization, cracking, and deviation of the domestic rubber belt under long-term high temperature conditions are inherent characteristics of rubber products, and it is impossible to completely solve the problem by a heat-resistant coating on the surface of the belt. It is difficult to accurately mix and prolong the stable distribution of clinker in production.
Second, the new board feeding scale measurement products improve the traditional batching process
In view of the above problems in the batching process of the cement industry, if the above-mentioned plate feeder and the belt measuring scale can be combined into one, a truly integrated high-precision chain plate scale can be realized, which can not only solve the tape type dosing The machine can not withstand the problem of large warehouse pressure, and can effectively reduce the cost of the construction of the raw material storage tank, avoiding the problem that the board feeding machine and the quantitative feeder are difficult to adjust synchronously, and at the same time bring the thoroughness of the ingredients of the high temperature clinker. s solution.
This will undoubtedly be a revolution in the field of dynamic weighing. After years of research by technicians, a new type of plate-feeding scale with all-steel structure came into being.
Because the board feeding machine pulls the material out of the bottom of the library through a series of rigid frames with all-steel structure such as sprocket, chain, chain plate, cam, light rail and transmission. The traditional role is for the bottom of the stock. How to manufacture it into a high-precision metering product has always been a problem in the field of industrial control. How to accurately transfer the weight of the material on the chain plate chain to the load sensor at the lower part of the track is the key to making a high-precision plate feeding scale. Therefore, how to design a delicate force transmission mechanism has become the core of manufacturing board feeding scales.
At present, some domestic manufacturers who try to manufacture the board feeding scales cut off the track of the chain plate machine, and installed four load sensors under the track for force transmission and metering. However, since the traction force of the active sprocket to the chain is horizontally forward, and the gravity of the material carried on the chain plate is vertically downward, and the horizontal traction force of the former is much larger than the downward gravity of the material, the combined effect of the two materials The gravity cannot be effectively transmitted to the sensor, and the effectiveness and stability of the force transmission mechanism cannot be guaranteed, and it is difficult to ensure the measurement accuracy.
Therefore, how to eliminate the mutual influence of the horizontal traction force of the active sprocket chain on the downward gravity of the material is the key in the manufacturing process of the plate feeding scale.
Through years of painstaking research and development by scientific and technical personnel, combined with the application results of similar foreign products, the effective transmission of chain plates, chains and light rails has been solved satisfactorily. The general principle is: the running track is cut into four sections, wherein the outer two sections are bearing guiding orbits, and the outer two sections of the orbits only participate in the transportation and do not participate in the measurement. The middle two sections are weighing tracks. For the middle two weighing rails, the outer sides of the two rails are respectively fixed on the damper type rotating device. Since the chain passes through the force fulcrum through the horizontal traction force of the slewing damper, no torque is generated with respect to the horizontal traction force. The inner sides of the two sections of the track are superimposed with a high-precision reed structure, so that the weight of the material of the weighing section is concentrated on the load cell in the form of a moment. Compared with the rotary damper, the superimposed gravity is not only effectively transmitted to the load cell, but also eliminates the influence of the horizontal traction of the chain on the downward gravity of the material, thus ensuring the accurate transmission of the weight signal of the force transmission mechanism. Measurement is a true board feeding scale.
The speed measurement is because there is no belt slip like a belt scale, and the high-strength all-steel chain plate is not affected by the extension and stretching of the belt, and the speed measurement accuracy is better than the belt scale. High-precision detection based on two factors of weight and speed to ensure high precision of measurement results. The unique design of this metering form is a highlight of the new board feeding scale, which has obtained national patents.
Third, the case of the board feeding scale measurement products
Since there is no raw material drying equipment, the moisture in the clay storage is as high as 24%. Due to the size of the original feeding hopper (B600mm×H150mm×L1500mm), the belt scale often has broken shaft, stuck, slipped, etc. Stop.
Since the equipment replacement plate is fed, the size of the feed hopper has been increased to B1200mm×H600mm×L3200mm, which not only satisfies the conditions of the large warehouse pressure, but also completely solves the problem of poor clay blanking and unstable measurement. Downtime due to board feeding.
The original limestone production process uses a tape-type dosing machine bottom batching mode. Due to the large warehouse pressure, high hardness and large flow of limestone, belt crushing, slipping, broken belts, and wear and tear are often caused to seriously affect production.
After replacing the plate with 1600×5500mm, the maximum flow rate of the scale body reached 550t/h, the process condition was greatly improved, the accuracy of the batching was greatly improved, and the failure of the board feeding scale never occurred.
Due to the high temperature of the clinker out of the warehouse, the original belt scale often appears to be elongated after being heated, and the belt can not be corrected in the left and right direction; the belt surface is cracked and carbonized, the fault is frequent, and the belt replacement maintenance rate is high, serious Affect the stability of the amount of the clinker and the operating rate of the cement mill.
After replacing the all-steel structure of the board, the reliable and stable metering not only precisely controls the amount of the incorporation of the clinker, but also greatly reduces the production cost and equipment maintenance rate. It provides a strong guarantee for the stable and efficient operation of the entire production process.
The above-mentioned board feeding is said to have good performance in the large cement groups such as Conch, China Resources, Yali, Hongshi, Jinyu, Tongli, Zhongye Building Materials, Sinoma and Tower Brand, and is gradually being promoted.
Due to the overcapacity of the cement industry, the reduction of staff and efficiency, energy saving and cost reduction have become an important part of the management of production enterprises. Focusing on improving stable production processes and pursuing sophisticated and efficient equipment has become an industry consensus. It is hoped that by improving the adaptability of equipment, it will improve and simplify the shortcomings in the production process, so as to effectively grasp the stability and reliability of the production process.