Technical research and development of multiple air compressors centralized gas supply control system design and application Jianli Sun Jianzhang Zhanjiang Deli Carburetor Co., Ltd. Guangdong Zhanjiang 524043 practice proved that the effect is good and practical.
The pressure control process is as follows: When the system pressure reaches the upper limit of the set pressure of the pressure regulating valve, the pressure regulating valve 3 is opened, and the unloading valve 2 closes the intake passage against the spring force. At this time, the air compressor unloads and runs at no load, and the system pressure gradually decreases. When the system pressure is reduced to the lower limit of the set pressure of the pressure regulating valve, the pressure regulating valve is closed, and the unloading valve 2 opens the intake passage under the action of the spring force. At this time, the air compressor load is running, and the system pressure is gradually increased. The air compressor continuously reloads the load unloading load and is in an intermittent working state.
Description 1 air filter; 2 unloading valve; 3 pressure regulating valve; 4 safety valve; 5 pressure; 6 gas storage tank; 7 gate valve; 8 air compressor 2 asks our company's compressed air consumption is 12, and Many enterprises with large gas consumption use the centralized gas supply mode, that is, the operation mode in which the multiple machines are mutually combined with the reserve capacity and the pressure, and the number of air compressors is selected according to the actual gas load. Since the setting pressure of the pressure regulating valve of each air compressor is not possible, it is impossible to cause. Therefore, when multiple air compressors whose pressure is separately adjusted are linked, there will be a phenomenon of uneven load and low air pressure with low setting pressure. The machine always unloads first, and when the air pressure slowly drops to the set value, the load runs, and when the air pressure rises to the upper limit of the set value, it is unloaded first. The air compressor with a slightly higher pressure is always in working condition and there is no chance of running at an empty load. As a result, the air compressor of this type will be subjected to abnormal wear for a long time at full load, resulting in equipment damage.
3 The design of pressure centralized control system With the continuous development of science and technology, in recent years, in order to facilitate the monitoring of the operation of large and medium-sized air compressors, most manufacturers use microcomputer and acoustic photoelectric control technology in the compressed air system. Automatic control and unattended monitoring of power running. In the construction of the power of the new plant, it is necessary to consider the adoption of new technologies, which is also a requirement for national energy conservation and emission reduction. However, for the old enterprises in which the air compressors are equipped with new and old models and specifications, it is difficult to use the microcomputer control reform. In the years of practice, we have designed and perfected the centralized control of pressure, which is applied to the linkage control of various large, medium and small multi-machines in our company, which effectively solves the problem of uneven load in the centralized air supply of air compressors. The following describes in detail several ways of centralized control. 3.1 Pressure regulating valve parallel control 2 The principle is that when the system air pressure reaches a fixed value, the lowest setting pressure of the pressure regulating valve in all air compressors takes the lead, and the unloading circuit opens. . Since the unloading circuits of multiple air compressors are connected in parallel, as long as the machine is unloaded, all other machines are also unloaded. Similarly, when the system air pressure is low to a certain extent, the pressure regulating valve jumps back, the unloading circuit is disconnected, and all the air compressors return to the normal load state. Therefore, using this method of centralized pressure control can make all the disadvantages of uneven operation.
3.2 Electric contact pressure control Electromagnetic unloading valve 3 control principle is to take AC 220 power supply in the air compressor control cabinet, install a 1ç–‹ type small general-purpose relay in the cabinet, and use the adjustable upper limit lower limit signal of electric contact pressure 9 The electrical signal outputted by the contact pointer and the finger pointer is the pressure fluctuation range that the air pressure system needs to set, and the normally open and normally closed contacts of the control relay are alternately pulled through the coils of the relay to make the parallel control. In the gas path, the one-position electric control reversing valve exchange technology developed the Il direction, thereby controlling the unloading valves of multiple air compressors at the same time, and controlling the simultaneous unloading operation of the air compressor. Using this method to control the pressure value of the air pressure system is more accurate, and the adjustment is more intuitive and convenient.
9 electrical contact pressure; position through the solenoid valve.
The principle of the electric control circuit is as follows: Before the air compressor is started, the power switch is turned on. When each air compressor is started, the electric contact pressure pointer is below the lower limit and the system has no air pressure state, and the lower limit closes the load operation of each air compressor. When the pointer rises to the upper limit with the air pressure, the 3 upper limit is turned on and the air compressor is in the unloading dry running state.
The specific control process is as follows: When the electrical contact pressure refers to the pointer falling with the system air pressure to the lower limit of the set lower limit, the small relay coil is energized, the normally open contact is closed, the 1 coil is energized, the sweet 1 is closed and self-locking, and the normally closed Disconnected, 12 normally open and closed, the position-passing solenoid valve 1 is energized to cut off the control gas path, and the unloading valve of each parallel air compressor is opened under the action of the spring, so that the air compressor enters the load operation. When the pointer rises with the air pressure and leaves the lower limit pointer 3, the lower limit is broken, the coil loses power, and the normally open contact is broken to close the normally closed contact. Operate to the upper limit with 1 coil under 1 self-locking condition. When the pointer rises to the upper limit pointer with the air pressure, 3 upper limit is turned on, the anvil 2 coil is energized, 22 is closed self-locking, 阽21 interlocking is broken, 1 coil is de-energized, 12 is normally opened and the solenoid valve is de-energized, and the control is lost. The solenoid valve, 23 normally open and closed, the position-passing solenoid valve 2 is energized to open the control gas path, and the compressed air acts on each of the relief valves to close the unloading valve against the spring force, so that the air compressor is unloaded and operated. When the pointer drops from the upper limit of 3 with the air pressure, the 2 line is disconnected, and the anvil 22 is kept at 2 to the lower limit under the self-locking condition, and the above process is repeated. This repeatedly keeps multiple air compressors running synchronously.
3.3 Co-mixing control form 4 In practical applications, the above two modes can also be mixed and used, when the electrical contact pressure acts, thus ensuring no loss. The detailed control principle will not be described again.
For convenience of explanation, only two air compressors are exemplified in the above. The centralized control design of multiple air compressors is exactly the same. It is only necessary to pull the control parallel pipeline to realize synchronous centralized control.
4 Conclusions It is worth noting that in recent years, the control system of air compressors has become more and more advanced, and the frequency conversion technology has been widely adopted. For screw air compressors, the inverter can be changed by changing the speed of the screw rotor. The amount of exhaust gas is adjusted to achieve constant discharge pressure, and the energy saving effect is remarkable.
When designing a centralized air supply control system, it is possible to use similar advanced technologies and components to make the system control more accurate and faster. Practice has proved that this solution solves the problem of uneven load during the centralized air supply operation of multiple air compressors. It is undoubtedly a simple and practical design idea to change the workload and reduce the input cost.
Lu Yongxiang, editor, Hydraulic and Pneumatic Technical Manual, Mechanical Industry Press, 2002.
Air compressor series product manual, Liuzhou Fidelity Machinery Manufacturing Co., Ltd....Continued from page 106 3.5 User Management User management mainly includes effective configuration management of system user information, including role information 3.6 System maintenance System maintenance management mainly includes changing password And data backup, etc. 56.
4 Conclusion After the test, the function of the university electronic reading room book retrieval system meets the requirements of the school book management business process, and the functions of each module tend to be perfect, creating an integrated networked query management platform for the school, which makes different positions of different operations. Users can use the same platform to achieve data sharing and information exchange, and at the same time, it is more conducive to the development of school book management, and promotes the popularization and application of networked informationization of college campus network.
1 Yang Liping, based on the 3 architecture of the operating system teaching aid system research and development Changchun Da Hu Youzhen 1985, female, Guangxi Nanning Binyang County, teaching assistant, research direction computer application information management.
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