Application of the hottest Pfister quantitative ro

Application of Pfister quantitative rotor scale

Abstract] rotor scale is a new type of pulverized coal weighing and feeding device that can meet the special requirements of modern cement kiln burners. This paper introduces the performance, structural principle, application of the rotor scale and its comparison with the traditional pulverized coal feeder

[summary] the rotor weight is a new type of feed device for measuring pulverized coal weight which can satisfy the special demand for burners of modern cement rotary. The results show that DSC technology can be used to identify recycled plastics The author introduces properties, construction principles and application of the weight and makes a comparison with the Convention 4 spring type microcomputer force application system experimental machine the application of experimental force is automatically carried out through the spring type force application structure and the microcomputer controlled stepping electromechanical system. The stepping electromechanical (30) is through a pair of radial thrust ball bearings (31), (32), Transfer a pair of worm (28) and worm gear (29) operating pairs with a reduction ratio of 80:1

in the process of cement calcination, the pulverized coal metering and feeding device of the burner is the key to stabilize the thermal system of cement. The stability of combustion depends largely on the uniformity and stability of pulverized coal supply. Therefore, the metering and feeding device of pulverized coal is very important for the production of kiln system

I. traditional pulverized coal metering device

in China's cement production, most of the traditional pulverized coal feeding devices use weighing belt conveyor and screw feeder. The weighing belt conveyor used for pulverized coal must have explosion-proof sealing device, which not only increases the investment of the equipment, but also brings difficulties to calibration and maintenance. In addition, the deposition of pulverized coal on the load sensor will cause zero drift, which will increase the measurement error. The screw feeder is not an ideal pulverized coal feeding equipment because it can not measure the flow rate of materials and the measurement accuracy will be affected by the pressure change at the discharge

in recent years, the weight loss feeding system and impulse flowmeter feeding system are used for the feeding of pulverized coal into the kiln in the equipment imported from the world and China. The weight loss feeding system is basically a static measurement, so it has the advantages of high measurement and control accuracy, wide flow regulation range and so on. However, due to the need for vibration damping foundation and inelastic platform, this increases the infrastructure investment. At the same time, the weight-loss feeding system will have unpredictable results due to irregular volume measurement operation at the beginning of feeding. The impulse flowmeter uses the component force of the material gravity on the impact plate to measure. Because it does not measure the weight directly, the air flow near the impact plate is very easy to affect the measurement accuracy, and the measurement is not easy to be accurate when the density, fineness, temperature, humidity and plasticity of pulverized coal change. The working process of the impulse flowmeter feeding system is tracking control. The short-term accuracy is very poor, and any interference generated cannot disappear by itself, which directly affects the operation of the kiln. It can be seen that the weight loss feeding system and impulse flowmeter feeding system are not completely ideal pulverized coal feeding equipment

II. Structure and measurement principle of DRW quantitative rotor scale

the modern decomposition kiln outside the kiln hopes to have a pulverized coal metering and feeding device with high short-term accuracy and continuous and permanent weight measurement. It can not only eliminate the influence of the differential pressure generated by pneumatic transmission and material feeding on the measurement accuracy, but also directly send the pulverized coal from the pulverized coal bunker to the burner. It is a control feeding device integrating quantitative and transportation. Under this premise, German Pfister company developed DRW quantitative rotor scale

Figure 1 is the structure and schematic diagram of the rotor scale

the rotor scale is composed of rotor, installation frame, transmission device, weight measurement system and soft joints. The higher the content of PPO in the rotor and sealing plate, the better the heat resistance. It can be installed in an explosion-proof housing. The whole rotor scale shell and the transmission device of the rotor are suspended in a frame (30) as a whole. Two fixed rolling bearing seats (16) are hung on the frame to support the rotor scale. The third suspension device is connected to the weighing devices (17, 18) with load sensors. The feed pipe, discharge pipe and compressed air pipe of the rotor scale are all connected with the corresponding parts by soft joints

Figure 1 Structure of rotor scale

the feeding process of rotor scale is: pulverized coal is discharged directly from the pulverized coal bunker through the sliding gate (21), enters the rotor part (6) through the inlet soft joint (23), and the pulverized coal is taken away by the compartment of the rotor, rotated 225 ° to the unloading area. The air from the bottom compressed air pipe (25) blows the pulverized coal into the inlet and outlet (24) and sends it to the burner

the rotor shell is made of nodular cast iron, which is divided into two parts: the upper shell (2) and the lower shell (1). The upper shell is provided with a material inlet and a material outlet, and the lower shell is provided with an air inlet and a flange connecting the transmission device. The rotor (6) is a cast iron piece composed of two rows of staggered small compartments, and is connected with the drive shaft through the central hub. There are two sealing plates on the upper and lower sides of the rotor. The sealing plate is a special casting. The specific clearance between the rotor and the sealing plate can be adjusted by special screws on the housing. The whole rotor and sealing plate are installed in the shell of the rotor scale, and the explosion-proof design can withstand the sudden change pressure of 1 MPa. The reducer (10) of the transmission device is connected with the lower shell of the rotor scale with a flange. The DC speed regulating motor (11) is transmitted to the reducer through the toothed belt (8). The output shaft of the reducer is connected with the shaft of the rotor. The digital speed measuring motor (9) is connected with the driving device to measure the speed of the rotor through a contactless sensor. The weight measurement system is composed of load sensor balance and damping devices (17, 18, 19)

in order to ensure the reset reducibility and deviation stability of the weight measuring device, and to minimize the consumption of transmission power and the wear of internal parts, Pfister company has solved some special technical problems, that is, the hydrostatic bearing system used in the rotor scale and the internal seal of the loading device with pneumatic control. On the transmission pipe leading to the burner, the air barrier of the arc-shaped small chamber is formed by the pressure pipe method to feed, Clean the nozzle with an arc chamber with an exhaust pipe

Figure 2 huge market demand of the rotor scale control frame

the flow of pulverized coal is determined by the speed of the rotor of the rotor scale and the dynamic load of the rotor measuring device. This load is measured by the load sensor installed on the resistance strain gauge. The angular velocity of the rotor is measured by a contactless pulse transmitter, and the whole system forms the overall characteristics of the rotor drive. Figure 2 is the principle block diagram of microcomputer control for rotor scale. The microcomputer processor will