The lower conveyor belt conveyor is an important long-distance transportation special sounding in the production of most modern industrialized coal mines. The reliable, stable and economic operation of the lower belt conveyor during the normal maintenance period guarantees the normal and safe coal mine. Efficient production has important significance. At present, the brake systems commonly used in conveyor belt conveyors include mechanical brake block brakes, electromagnetic power brakes, hydraulic brakes and oil motor servo brakes. As far as the general situation of domestic coal mines is concerned, electromagnetic power brakes have less investment and stable performance. On the one hand, the braking system has a simple structure, on the other hand, the influence of coal mine production environment on electromagnetic power braking is relatively small, and its disadvantage is in the production process. In the event of a sudden power failure, the brake system will not work. This is not uncommon in the actual production process. From the perspective of the complexity of the brake system, the hydraulic brake system is relatively complicated and is transported in the lower belt. When the engine system speed is low, the braking torque is rapidly reduced, and the braking effect is ideal. The disadvantage is that the buffering time is slightly longer. For the mechanical brake block braking, due to the mechanical brake block material, processing precision, and lowering belt The working environment and wear level of the conveyor may cause sparks, cauterization and pitting, which not only affect the braking effect of the lower belt conveyor, but also cause damage to the mine production safety, thus hydraulic braking. It seems to have more and more advantages. 1 Principle and basic structure of the brake control system for the belt conveyor under the coal mine The principle of the L1 brake control system The modern conveyor belt conveyor features long conveying distance, large conveying capacity and continuous non-intermittent operation, so high power The lower belt conveyor is widely used in most coal mines, and the basic principle of selecting a high-power belt conveyor is: stable operation, long service life, good braking performance, easy maintenance, and excellent safety performance. The braking performance is directly affecting the safe and reliable operation of the lower belt conveyor, which is one of the important factors in selecting the sound. The braking effect is mainly reflected in the following aspects. The braking torque is small, the braking torque can be controlled, and the braking process must be smoothed down to zero and the force distance disappears. The system has the reliable braking performance of the self-locking of the power-off mechanism as a guarantee. Has a selectable small range brake function. It has a zero-speed hold function for heavy-duty starting brake torque. The multi-machine simultaneous braking torque balances each other. Has good underground explosion-proof performance. The versatility of the spare parts is good, the accessories are easy to get, and the price is cheap. The basic structure of the L2 brake control system The brake control system of the coal mine belt conveyor mainly includes the control system, the brake system, the belt conveyor drive system and the multiple number feedback feedback system. When the control system receives the master control number and requires the hydraulic brake reversing valve to perform the brake commutation, that is, outputting an oil motor reverse braking torque to the belt conveyor transmission system, the control system also sends a control electric multiplier at the same time. Then, the electric speed sensor system feeds back the working speed multiple and the reverse braking multiple to the control system, and the control system can realize the adjustment function of the torque according to certain indexes to make the braking of the belt conveyor transmission system. Meet the working conditions. 2The function and function of the brake device The braking technology of the lower conveyor belt conveyor is relatively mature. The brake systems of various braking modes have formed a standard series. The high-power controllable dynamic devices that have been successfully applied and developed are mainly There are: disc brakes, hydraulic brakes, hydraulic brakes and mucus controllable actuators. However, for the coal mine working environment, the hydraulic oil motor brake system is more advantageous. 2.1 Disc brakes Disc brakes, also known as disc brakes, are named after their shape. It is controlled by hydraulic pressure. The main components are brake discs, sub-pumps, brake calipers, and oil pipes. Producing a brake disk Alloy Steel rotary shaft and fixed to the main machine, with the mechanical rotation. The sub-pump is fixed to the bottom plate of the brake and fixed. The two friction plates on the brake caliper are mounted on both sides of the brake disc. The piston of the sub-pump is hydraulically driven by the oil pipe, pushing the friction plate to frictionally brake against the brake disc, and it acts as if the pliers are used to clamp the rotating plate and force it to stop. The brake has the advantages of quick heat dissipation, light weight, simple structure and convenient adjustment. Especially when the load is high, the high temperature resistance is good, the braking effect is stable, and it is not afraid of muddy water attack, and the environmental requirements are not high. Of course, disc brakes also have their own drawbacks. For example, the manufacturing requirements of the brake and the brake pipe are high, the wear of the friction plate is large, and the cost is responsible. Moreover, since the area of ​​the friction plate is small, the working surface of the relative friction is also small, and the required brake hydraulic pressure is high. The hydraulic brake hydraulic brake is essentially a turbine oil drive motor. It generates a high-speed liquid flow and hydraulic pressure in different directions of rotation through a commanded multiple to generate a large resistance torque, so that the hydraulic power generation of the belt conveyor decelerates. Even cooperation. It can simultaneously change the braking torque by adjusting the different direction or the unidirectional filling amount to realize the controllable moving function of the lower belt conveyor. It mainly consists of system oil pump and control system, hydraulic brake coupling of turbine oil motor and hydraulic cooling control system. When the belt conveyor is in normal operation, the brake oil motor is not filled with hydraulic pressure in the reverse oil chamber. When braking is required, the control system issues a braking command to input the liquid in the opposite direction and give the required pressure according to the braking strength. The braking torque is adjusted according to the amount of liquid charged and the pressure of the liquid. When the lower belt conveyor is working normally, the hydraulic motor brake system is in a zero state in the reverse direction. The hydraulic brake device is divided into two types: hydraulic pressure brake and hydraulic speed brake in the hydraulic brake device. Its working principle is to connect the positive displacement oil pump to the main drive shaft of the belt conveyor. When the main engine is working, the volumetric oil pump is driven to rotate synchronously. When braking, the oil pump converts the mechanical energy into hydraulic energy, and adjusts the braking torque of the main transmission shaft by adjusting the pressure of the pump outlet pressure, thereby achieving the purpose of the belt conveyor braking. The hydraulic speed control brake, also known as the hydraulic speed control brake device, is currently one of the main braking methods for the belt conveyor under the coal mine. It has the function of setting the auxiliary auxiliary rib or overload protection. The main purpose of applying hydraulic speed control brakes in coal mine belt conveyors is to ensure smooth braking and no need for system coolers. At the same time, it can solve the problem of speed regulation and pressure shock of high pressure and large flow hydraulic circuits, and the braking effect shows uniform deceleration. The braking force is also uniformly decremented, which is very beneficial to the overall performance and service life of the lower belt conveyor. The mucus-controllable liquid-liquid-controllable movable device works in the same way as the liquid-viscous controllable soft starter. It uses the friction of a mechanical friction plate in a viscous liquid to transmit and change the direction of the torque and increase the resistance. In order to meet the requirements of the coal mine production environment and the various braking performance requirements of the belt conveyor, the liquid-viscous controllable moving device adopts a closed structure. Under normal working conditions, the friction plate embedded on the drive shaft rotates at the same time as the drive shaft, while the driven friction plate does not move under normal working conditions. When the oil pressure in the control cylinder is changed, the pressing force between the main and driven friction plates can be adjusted, so that frictional force is generated between the main and driven friction plates, thereby changing the friction torque between the active friction plates and the driven friction plates. Finally, the requirements of various braking indicators of the belt conveyor are realized. During the braking process, the braking torque increases as the oil film gap decreases and the pressing force increases, and decreases as the braking speed decreases. Therefore, during the braking process, the oil film gap should be continuously reduced to ensure a certain braking torque. The liquid-viscous controllable moving device has a simple structure: it can provide adjustable, smooth and non-impact braking torque; a hydraulic station can be used for multiple braking at the same time; the belt conveyor can realize automatic overload protection when overloaded; The mucus controllable device has safe and reliable use, small braking torque impact and good use effect; the main and driven friction plates of the liquid-adhesive controllable moving device work in viscous lubricating oil, which is cooled by lubricating oil. It can save cooling water, save operating costs and maintenance workload, and extend the service life of the machine. Therefore, the liquid-adhesive controllable moving device is currently a better brake device for coal mine belt conveyors, which is especially suitable for the development and application of long-distance, high-power 34Ki information technology industrial technology 10kV switchgear Pan Yudong Wang Wei (Shenyang Industrial Installation Engineering Co., Ltd. Shenyang 1990, the 10kV switchgear in the urban power grid in Tianjin is mostly GC-IA (F) fixed, semi-closed switchgear, which was improved by the open switchgear in the early 1980s. For example, eight 10kV switchgears in the 10kV transformer room project of the Institute of Physics of our company in 1994, and 8 GG~1A switchgears in the 10kV transformer room project of Dacheng Hardware Factory, which are characterized by: Wide and tall, clear structure, easy maintenance and repair. This type of switchgear has a history of decades of production, reliable product performance, semi-closed for easy inspection and observation, and is convenient for hanging the grounding wire during busbar maintenance. After long-term operation practice proves The operation and maintenance of this kind of switchgear are safe and reliable. However, the main disadvantage of this switchgear is that the cabinet is large and the breaking capacity is poor. It is not suitable for the urban area where the gold is in place. It was gradually phased out in the late 1990s. The hand-cranked switchgear is a mobile switchgear, the floor-standing type is hand-car type, and the center-mounted type is drawer type. This type of switchgear is only required to be replaced during overhaul. The handcart can shorten the blackout time and is suitable for places where the load is more important or the building area is smaller. The 10kV switchgear of the 10kV substation of the international shopping mall between the Nanjing International Shopping Mall and the Geely Building built by our company has been selected. Handcart cabinet. Since this station is a follow-up project, the planned area is small, and the whole station is a three-story building. Since the reliability of commercial power supply is very important, the business hours cannot be interrupted, so this type of hand truck cabinet is chosen. The characteristics of the cabinet are: safe and reliable operation, low investment and simple maintenance. The hand truck switch cabinet is fully enclosed and mobile, the trolley can be pulled out for maintenance and interchangeability, so it is safe and reliable; the spring operating mechanism can be used for general alternating current. The price is relatively low; the vacuum circuit breaker is maintenance-free; it has five anti-interlock functions, and the circuit breaker can be automatically opened when the electrical circuit is mishandled; When the road device is in the closing position, the grounding knife gate cannot be closed. However, we found in the construction that due to its five-proof function and full-closed feature, the back cover cannot be opened before the grounding knife gate is closed, and the power cannot be checked. After the user runs this station, it is found that when the hand truck cabinet is pulled out along the ground, the green carpet must be placed in front of the switch cabinet, which makes the hand truck in and out very inconvenient. Moreover, the installation and debugging process of this type cabinet is more complicated, and gradually in the construction. It is eliminated. 10kV ring network switchgear. 10kV ring network switchgear is a switchgear that can realize ring network power supply. It is assembled by factory according to fixed combination requirements, and is suitable for urban distribution network with short circuit capacity below 500MVA. In order to connect and protect the transformer of 25~2000kVA, it can also be used as the power distribution and sound, and can also be used as the high-voltage side power supply of the box-type substation. This cabinet generally has a locking and charging display device. The medium is divided into air type and sulfur hexafluoride type. According to the different cabinet structure, it is divided into three loop unit, four loop unit and multi loop unit. Commonly used functional units are line load switch, transformer protection (protection mode with fuse load switch, combined fuse load switch and circuit breaker), bus (cable) inlet and outlet (with or without voltage transformer), metering unit (including current and voltage transformers and grounding switches). The three-loop unit is a typical structure of a ring network switch cabinet, that is, it consists of two line load switch units and one transformer protection unit. The sulphur hexafluoride ring network switchgear, except that the fuse is separately installed in a sealed metal casing and the operating mechanism is located outside the casing plate, all other functional circuits and conductive parts are installed in a hexafluoride filled with a gauge pressure of 0.1 MPa. The metal sealed box of sulfur gas is compact, small in size and unaffected by the external environment. Some products only use SF6 load switch, other main circuit parts are closed with solid green material, which can also greatly reduce the size of the ring network switch cabinet, and the price is cheaper. With the optimization of the cable distribution structure in the urban power grid, after the year 2000, we have adopted the ring network structure and the multi-circuit power distribution opening and closing station and the opening and closing station mode in the Tianjin regional power grid reconstruction. The SF6 all-green switchgear has Fully enclosed, maintenance-free, small size, excellent performance, safe and reliable, it is very popular among users. The ring network cabinet was developed from the original air-green ring network power distribution unit to the compact SF6 ring network power distribution unit. Recently, it has developed into a scalable SF6 all-green ring network cabinet and multi-loop power distribution cabinet, making the SF6 completely The green switch technology has made great progress and development. In particular, computer technology, electronic technology, sensing technology, optical fiber communication and other technologies are applied to ring network cabinets and multi-loop power distribution cabinets, making products more compact and intelligent. In the distribution project of residential quarters built by our company in 2007, the 10kV switchgear of the substation room adopts the UhiSWtch series of SF6 all-green ring network cabinet. For example, the two substation rooms in Haiyunjiayuan Community of Hebei District have adopted 6- and 9-face UhiSwitch series cabinets, respectively, with 2 sets and 3 sets of 800kVA dry type transformers. The substation room in the Jundong apartment residential area on the south side of Jinbin Avenue in Hedong District has selected 10 UhiSwitch series cabinets with 4 1000kVA dry-type transformers. At present, the substation room in the Yueyun apartment complex in Hebei District has selected 9 UhiSwitch series cabinets with 3 sets of 1000kVA transformers. The SF6 all-green ring network cabinet and multi-loop power distribution cabinet have the following technical features: 1 cabinet is small. The three-position rotary load switch is used to effectively reduce the number of parts and realize the mechanical five-proof interlock. The vacuum circuit breaker is filled with SF6 green gas to make the overall structure more compact; the current limiting fuse is also developed to miniaturization, and the combination of the two, the cabinet is getting smaller and smaller. 2 High absolute performance. The cabinet adopts a sealed stainless steel casing armor structure, and there are metal partitions between the busbar room, the switch room and the cable room. The partial protection level of the all-green structure can reach IP67. The airtightness is very good, and the gas consumption is small. Guaranteed for 30 years without air leakage, in line with environmental protection requirements, indoor, outdoor, underground, semi-subterranean substation can be used. 3 modular design. Each unit module can be combined and expanded arbitrarily without charging and discharging gas, which is convenient for design of the solution and high-pressure metering, and has a wide application range. 4 operating mechanism is reliable and durable. The operating mechanism inside the cabinet is made of corrosion-resistant metal. The bearings in the rotating part are self-lubricating. The product is not affected by the environment, it is free of regular maintenance, and it is convenient to connect with the outside world, so that the operation is small, the reliability is high, and the service life is longer. 5 easy to transform. The expansion busbar in the cabinet adopts plug-in silicone connector, which is completely green and shielded, ensuring electrical conductivity reliability, convenient connection and expansion, and convenient for users or substation to increase capacity. 6 cable head connection is safe and reliable. The terminal part of the connecting cable in the cabinet is prefabricated with a green rubber cable terminal on the front side, which eliminates the disadvantage of inconvenient cable installation caused by the small cabinet. It can be disassembled during maintenance, quick recovery and easy installation. The outer surface is made of a new type of semiconductor material as a shielding layer. When the surface is grounded during operation, it is not affected by moisture, condensation, dust and dirt, and has higher safety and maintenance-free. Based on the above advantages of 10kV SF6 ring network cabinets and multi-loop power distribution cabinets, it is being adopted by more and more urban power supply networks. Its various technologies will also be developed and improved in practice for a longer period of time. Steel Casting Parts,Accurate 3D Printer,3D Print Automotive,3D Print Engineering Guangdong Fenghua Zhuoli Technology Co., Ltd , https://www.fhzl3dprinter.com
Analysis of Brake Control System for Belt Conveyor in Coal Mine
Brake control belt conveyor coal mine industrial technology systems analysis Zhang taboo (in Taiyuan Coal Jian seventh Agency conveyor replaced by modern coal mining production processes used in high-power, long-distance belt conveyor More and more. Braking device is one of the key equipment and control system of the lower belt conveyor. In recent years, with the continuous development of the belt conveyor in China, the braking technology is also constantly improving.