Application of ATOS Cartridge Valve in Hydraulic System of Electro-hydraulic Control Bracket

Application of ATOS Cartridge Valve in Hydraulic System of Electro-hydraulic Control Bracket
The application basis and prospect of the Italian ATOS Atos cartridge valve in the hydraulic system of the electro-hydraulic control bracket are discussed. The design scheme is proposed and the working principle is analyzed. It is considered that the cartridge valve has large flow capacity and fast response, and adopts electro-hydraulic pilot control, which is especially suitable for the working condition of the bracket, which is in line with the development trend of the technology and is worth promoting.
1. Application basis analysis
Low moving speed has become an important factor limiting the production of fully mechanized coal. In order to speed up the transfer speed, a cartridge valve is used in the hydraulic system of the bracket. The cartridge type directional valve also uses a solenoid valve as a pilot valve to perform pilot control on the main valve (cone valve). The control principle is equivalent to the electro-hydraulic control valve, but the flow-through capability of the cartridge valve (up to 10000 L/min or more) is large. The outstanding advantages of fast response and reliable operation are unmatched in the tube valve, making it more suitable for use in the electro-hydraulic control system of the bracket, without the need to develop a special high-flow main valve using electromagnetic pilot control. To meet the requirements of use, it can improve the performance of work, improve the degree of generalization, and fundamentally solve the problems caused by the inherent defects of the tube valve.
In addition, the use of cartridge valves to design the bracket hydraulic system has the following advantages:
1) The advantages of the Italian ATOS Atos cartridge valve are very suitable for the working condition of the bracket.
The working conditions of the hydraulic support are: low viscosity of the medium, high working pressure, large flow, poor working environment and serious media pollution. The advantages of the cartridge valve can be fully utilized.
2) Comply with the development trend of fluid transmission technology.
In order to reduce the cost of use and eliminate environmental pollution, fluid transmission technology is moving toward the use of pure water media. The hydraulic support is a high-water emulsion with similar properties to pure water as the working medium. It is likely to be the beneficiary of the development of this technology and is tending to use pure water working medium. Due to the low viscosity of the water, the sealing of the valve is required to improve the efficiency of the system. The cartridge valve has a tapered seal and has excellent sealing performance. It is more suitable for working in pure water medium and should be the preferred valve for pure water support.
3) Strong anti-pollution ability and reliable work.
The bracket works on the coal mining surface, and the degree of medium pollution is high, which causes serious damage to the valve core and shortens the service life of the valve, thereby causing various failures of the bracket, reducing work reliability, increasing maintenance time, and reducing work. Productivity. There is no strict matching requirement between the valve core and the valve sleeve of the cartridge valve. It is lightly worn, not easy to block, and does not cause hydraulic clamping. It can still ensure the normal and reliable operation of the hydraulic system of the bracket when the medium is dirty.
4) Meet the needs of certain special working conditions.
For example, for a support bracket that is strong and hard to fall off the top plate during the period of pressure, when the old top suddenly presses, the safety valve in the lower chamber control valve of the column must pass a large instantaneous flow rate, and the ordinary safety valve is passed. The flow capacity is far from meeting the flow requirements, so an inflatable large flow safety valve has been specially designed to adapt to this condition.
However, the valve has a complicated structure, is difficult to manufacture, has high assembly requirements, and has poor work reliability, and is difficult to meet the use requirements. Moreover, the lower safety chamber of the column is also equipped with a common safety valve to meet the needs of normal working conditions, which will undoubtedly increase the number of components and manufacturing costs. The use of a cartridge-type relief valve makes it easy to solve this problem and simplifies the system.
Application of ATOS Cartridge Valve in Hydraulic System of Electro-hydraulic Control Bracket
2, working principle analysis
Based on the above analysis, the design idea and scheme of designing the hydraulic system of electro-hydraulic control bracket with cartridge valve is proposed.
The system consists of two parts, electric and hydraulic. After the microcomputer (center and bracket controller) that stores the action program of the bracket sends out the command, the electromagnetic pilot valve in the cartridge type directional valve first acts to open and close the corresponding two-way cone valve. , turn on or off the column or move the oil circuit of the jack to make it move in a certain order. The working condition of the column or the shifting jack is fed back to the controller by the pressure and displacement sensors, and the controller determines the next action based on the feedback signal.
Since the central controller and the stand controller are connected to the Internet, the action of any one of the work faces can be controlled from the central controller or the controllers of the respective frames.
The role of the central controller is to control and coordinate the controller of each bracket. In addition, it can automatically program, modify system parameters, monitor the working status of each bracket, and display the speed of the shearer. It provides individual control, sequence control, group control and fully automatic control of the various movements of the stand.
The bracket controller directly controls the bracket through the cartridge directional valve, and transmits the data collected by the sensor to other brackets and the central controller. After receiving the signal, the bracket hydraulic system will complete the following actions:
1) The action of the lifting column is controlled by the cartridge type directional valve 8. When the electromagnet 1YA of the pilot valve in the directional valve 8 is energized, when the 2YA is de-energized, the valve is switched to the left position, and b of the four 2-way valves The upper chamber of the d is pressurized, and the oil is in the closed state. The upper chamber of a and c is open to the fuel tank, and the pressure medium supplied by the pump station passes through the 2-way valve c and the hydraulic control check valve. The two-position three-way pilot valve is in the position shown in the figure, and the 2-way valve in the same normal check valve enters the lower chamber of the column, and the emulsion in the upper chamber of the column is returned to the liquid through the two-way valve a in the directional valve 8. The column is extended to achieve the lifting.
The rodless cavity oil passage of the column is provided with a control valve group composed of a plug-in hydraulic control check valve and a relief valve. When the top beam contacts the top plate, the pressure in the lower chamber of the column rises to the unloading pressure of the pump station, the hydraulic control one-way When the valve is closed, the bracket reaches the initial supporting force; after that, as the top plate sinks, the pressure of the lower chamber of the column rises to the set opening pressure of the overflow valve, the overflow valve is opened and unloaded, and the pressure of the lower chamber of the column is lowered again. When the pressure in the lower chamber of the column is lowered to the closing pressure of the relief valve, the relief valve is closed again.
Thereafter, the above process will be repeated to change the pressure in the lower chamber of the column near the set value of the relief valve, and the support operates in a constant resistance support state. Due to the fast response speed of the cartridge valve, the pressure in the lower chamber of the column is small, and the constant resistance of the bracket is good, which is beneficial to the management of the top plate.
The system also realizes three stages of initial support, increase resistance and constant resistance during the lifting process of the bracket. The initial support force is determined by the pump station pressure, and the working resistance is determined by the set pressure of the relief valve.
2) When the frame is lowered, the electromagnet 2YA of the pilot valve in the cartridge type directional valve 8 is energized. When the 1YA is de-energized, the valve is switched to the right position, and the upper chambers of a and c of the four two-way valves are pressurized with oil. In the closed state, the upper chamber of the b and d is in the open state, the pressure liquid supplied by the pumping station enters the upper chamber of the column through the two-way valve b, and the pilot valve in the pilot operated check valve is switched to the right position. The upper chamber of the two-way valve is opened to the fuel tank, and the oil in the lower chamber of the column is returned to the liquid through the two-way valve in the pilot valve, and the column is retracted to reduce the frame.
After the down frame is finished, the pilot valve in the directional valve is placed in the middle position of the figure (1YA and 2YA are all powered off). At this time, the upper chambers of the four two-way valves are all connected to the pressure oil, which is in the closed state. The oil passages are also closed, and the bracket stays at a certain height position, ready to be moved.
3) Pushing and shifting the action of the jack is controlled by the cartridge type directional valve 9 when the pilot valve in the directional valve is placed in the right position (4YA energized, 3YA powered off) and left position (3YA energized, 4YA powered off) At the time of the control, the extension and retraction of the piston rod of the jack are respectively controlled to realize the push-and-slide.
After the shifting action is completed, the pilot valve is placed in the neutral position (3YA and 4YA are de-energized), and the upper chambers of the four two-way valves e, f, g, and h are all pressurized, and are in the closed state, and the two chambers of the jack are moved. The roads are closed and the shifting action stops. After receiving a new command, the bracket will start the next action cycle.
When the electromagnetic pilot valve in the directional valve is replaced with a manual valve, the hydraulic system of the existing manual control bracket can be designed with the cartridge valve to improve the working performance of the bracket and improve the working reliability. The analysis shows that the hydraulic system of the electro-hydraulic control bracket designed with the cartridge valve can meet the working requirements of the bracket. Based on the same principle, the hydraulic system of all types and models of hydraulic brackets can be designed with the cartridge valve.
3. Feasibility analysis
1) The performance characteristics of the Italian ATOS Atos cartridge valve are suitable for the working conditions of the hydraulic bracket and can meet the requirements of its use.
2) The functions of the various valve components used in the modern bracket hydraulic system can be realized with the corresponding cartridge valves. The hydraulic system of all types and models of electro-hydraulic control brackets can be designed with the cartridge valve.
3) The advantage of the easy integration of the cartridge valve makes the structure of the control valve group compact and easy to install.
4) There are mature electro-hydraulic control systems and explosion-proof electro-hydraulic control components available.
5) The production of cartridge valve components has been serialized and generalized, and the manufacturing and use costs are relatively low.
4, the conclusion
1) The cartridge valve is convenient for electro-hydraulic control, large flow capacity and fast response. It is especially suitable for the working conditions of the hydraulic support using electro-hydraulic control. The hydraulic system of the bracket is designed to have superior performance, meet the requirements of use and move quickly. The need for the shelf is conducive to generalization, serialization and standardization.
2) The excellent sealing performance of the cartridge valve is more suitable for application in pure water brackets using pure water medium.
3) The cartridge valve has strong anti-pollution ability. When the medium is dirty, it is not easy to block and wears lightly. It can prolong the service life of valve components, reduce faults and improve the working reliability of the bracket hydraulic system.
4) Designing the hydraulic system of the electro-hydraulic control bracket with the cartridge valve, in accordance with the production requirements, in line with the development trend of the roof support technology and fluid transmission technology of the fully mechanized mining face, technically barrier-free, economically feasible, and worth promoting.