Our air compressor is the core unit of the air separation workshop, which plays a vital role in the system of the plant and downstream equipment. The oil pump of the air compressor is one of its important auxiliary equipment. The normality of the oil pump is directly related to whether the air compressor can operate normally. Each unit adopts two oil pumps A and B to open and prepare. However, due to various drawbacks in the design and installation of crude oil pump electrical control, it will pose a potential threat to the safe operation of the air compressor, endangering the system pipe network pressure, and each production. The device will be affected by this to reduce production or stop work, resulting in immeasurable economic losses. 1.1 Original control principle and existing problems of air compressor oil pump In the original design of a chemical plant air compressor, two oil pumps A and B were opened and equipped with low oil pressure switching operation function. Each unit was equipped with oil pump shutdown and low oil pressure shutdown. Interlocking. Whether the operating conditions of the A and B oil pumps are good, directly affects the stability and long-term operation of the air compressor. The control principle of the oil pump is: the switch 31SA is turned to the "on" position, the contactor KM1 is energized to close, the oil pump is running; at the same time, the KA11 and KT11 are closed, and the KT11 is delayed to close the contact to make the running oil pump self-holding and with anti-shake function; Among them, KA12 cuts off the main contactor of the oil pump and the KA11 circuit when the oil pump is stopped; in addition, KM2 is the standby oil pump contactor, KC4 is the auxiliary contact of the air compressor operation, KC6 is the low oil pressure interlocking start reserve oil pump contact, the air compressor is During operation, the auxiliary contact KC4 is closed, and the low oil pressure KC6 is closed to make the KT12 energized and closed. The oil pump is provided. Similarly, when the operation oil pump fails, the KM2 normally closed contact returns, and the KT12 is closed and the oil pump is provided. 2 The air compressor oil pump has three self-stops, and there is no fault alarm signal. Fortunately, the spare oil pump motor and the oil pump are normal. The low oil pressure interlock activates the reserve oil pump to ensure the normal operation of the air compressor, otherwise it will lead to the unit connection. The lock is stopped. 2 After the air compressor oil pump is switched, the electrical maintenance personnel of the factory immediately carried out a comprehensive inspection: the main circuit of the oil pump drawer cabinet and the control circuit are tested normally, the first and second lines are wired correctly, the components in the cabinet are intact, and the power is transmitted. After booting normally. After a period of time, the same problem occurred. 1 The air compressor oil pump stopped 2 times, and the 2 air compressor oil pump stopped once, which brought great pressure to the electrical maintenance work of the plant. The design of the crude oil pump control circuit is more complicated, see. After multiple analysis of the electric control principle of the oil pump and the live operation test of the electric control circuit, it was finally found that there is a parasitic circuit between the oil pump field control cabinet and the power distribution room switch cabinet. The induced voltage generated by this parasitic circuit makes the oil pump contactor coil When the voltage is lower than the action value, the voltage difference of the contactor coil voltage is reduced and the action is made, so that the oil pump in operation is stopped. Through further testing, it was also found that the spare core of the oil pump control cable has an induced voltage of about 90V. Original control schematic diagram of air compressor oil pump (see next page) Position map of air compressor oil pump 31SA transfer switch (see next page) Electric control air compressor oil pump original control principle 1SA transfer switch handle position circuit number contact number stop After analyzing the position map of the air compressor oil pump 31SA transfer switch and diagnosing the cause of the self-stopping of the oil pump, the electric maintenance personnel immediately organize technical research. After receiving the authorization of the various departments of the plant, according to the control principle, start-stop mode and production of the oil pump It is required to redesign the electrical control schematic of the air compressor oil pump without changing the original design function, as shown in the figure (1, 2 air compressor oil pump control principle is the same). The electric control circuit is divided into two parts: “manual†and “automaticâ€, the BK switch is turned to the “manual†position, and the standby oil pump BK switch is required to be in the “automatic†position. The original complicated position switch control was changed to button interlock control (the original control circuit 31SA transfer switch is also extremely fragile and difficult to repair, and the maintenance pressure can be greatly reduced after cancellation). After redesigning the design, the circuit between the oil pump field control cabinet and the power distribution room switch cabinet is four fewer than the original design, and one intermediate relay is used less, which greatly reduces the generation of parasitic loops. After the drawings are submitted to the higher authorities for review and approval, the electrical maintenance personnel carefully organize and prepare for the technical transformation with the strong support and cooperation of the factory, production workshop and electrical department. Improved air compressor oil pump optimization schematic diagram (see next page) Improved air compressor oil pump optimization principle diagram Machine A, B oil pump has carried out electrical control loop optimization pilot transformation, and at the same time the power distribution room switch cabinet to the field control cabinet The control cable spare core wire is all short-circuited to ground, so that the induced voltage of the oil pump control circuit is greatly reduced. At the same time, the oil pump low oil pressure switching operation and anti-shake function are thoroughly tested, and the commissioning is normally accepted and delivered, from February 2011. So far, no air pump self-stop accident occurred in the air compressor. Because the 2 air compressors do not have the construction conditions, the electrical maintenance personnel took temporary precautions against the electrical control loops of the two air compressor oil pumps: the air compressor oil pump power distribution room switch cabinet to the control cable of the field control cabinet. All the wires are short-circuited to ground, so that the induced voltage of the control circuit is reduced, and the normal operation of the air compressor oil pump can be temporarily guaranteed. Once the air compressor and the oil pump motor are shut down, the control loop transformation is implemented immediately. It is only a matter of time to solve this problem. So far, this technical breakthrough has been successful. At the same time, the plant electrical maintenance team also organized the learning and technical digestion of the new schematic diagram of the oil pump, and predicted and analyzed the loop fault to accelerate the response mechanism and processing speed of the oil pump circuit failure. After optimizing the air compressor A and B oil pump control loops, the electrical control is more reasonable and reliable, which greatly reduces the maintenance pressure. The nitrogen production of the plant is further guaranteed. 2 The air compressor oil pump control circuit will also be rebuilt in May-June 2012. It has been in operation for more than three months, and the air compressor unit is running smoothly. This has completely eliminated the hidden dangers of such equipment left by the air separation air compressor system. It provides a strong guarantee for the stable production of the plant. Components For Automobile Dies
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The stamping parts on the car body are roughly divided into cover parts, beam parts and general stamping parts. The stampings that can clearly characterize the image of the car are car covers. Therefore, a more specific car mold can be said to be "a stamping mold for automobile cover parts". Referred to as the automobile cover die. For example, the trimming die for the outer panel of the front door, the punching die for the inner panel of the front door, etc.
Of course, not only the body of the car has stamping parts. The molds of all stamping parts on automobiles are called "auto stamping dies". The summary is:
1. Automobile mold is the general term for the molds that make all the parts on the car.
2. Auto stamping die is a die for stamping all stamping parts on the car.
3. The automobile body stamping die is a die for stamping all stamping parts on the automobile body.
4. The stamping die for automobile cover parts is a die for punching all the cover parts on the car body.