【Abstract】 It is introduced that in the “one tank to the bottom” technical transformation project of Ningbo Goldshine Electronic Co., Ltd, the technical improvement and improvement have been carried out in view of the many failures and equipment hidden dangers that occurred after the installation and use of 16 blast furnace bottoms. Metering performance has been improved, equipment failure rate has been reduced, equipment support capability has been improved, equipment maintenance intensity has been reduced, and good results have been achieved.
[Keywords] continuous molten iron scale; weighing sensor; installation method
Since February 2013, Ningbo Goldshine Electronic Co., Ltd Company has installed a total of 16 continuous rail iron water scales in each blast furnace bottom for the weighing and measurement of molten iron tank cars. This project is also known as the “one tank to the bottom” metering device installation project. However, after the project was put into use for a period of time, comprehensive factors such as the corresponding management work and the external environment of the continuous rail water scale were not improved and implemented simultaneously, resulting in the stability and scale of the continuous rail water scale equipment at the bottom of the blast furnace. The measurement accuracy was once disturbed, which directly affected the use effect and accuracy of the “one tank to the end” continuous rail iron water scale. Because the blast furnace bottom continuous rail iron water scale was put into use for the first time in Ningbo Goldshine Electronic Co., Ltd Company, it was not feasible to use it. And maintenance experience. In view of the current situation, how to ensure the long-term stable operation of the blast furnace bottom continuous rail water balance equipment, effectively extend the service life of the continuous rail water balance weighing sensor, fundamentally minimize the time for weighing equipment troubleshooting, and reduce maintenance costs To improve the efficiency of hot metal direct installation, we organized a number of technical research and improvement work on the original installation of 16 sets of 300-ton continuous rail iron water scale equipment at the bottom of the blast furnace, and strived to promote the long-term stable operation of the weighing equipment And accurate measurement, to better play an active role in the blast furnace production of Ningbo Goldshine Electronic Co., Ltd Company.
- Transform the original fully enclosed continuous rail water scales into “bare scales” operation
As the “one tank to the end” continuous rail water scale was applied for the first time in Ningbo Goldshine Electronic Co., Ltd Company, everyone lacked practical experience in the maintenance and use of the “one tank to the bottom” continuous rail water scale. At the beginning, the focus was on the blast furnace “iron running” accident. The bottom of the blast furnace is devastating damage to the continuous rail water balance. Therefore, the protection method and installation purpose of the continuous rail water balance of the blast furnace are formulated: to minimize the continuous rail water balance caused by the blast furnace molten iron “running” or molten iron splashing. Burn damage. In the initial stage of installation, the surface of all the weighing sensors on the continuous rail iron water scale at the bottom of the blast furnace shall be covered with asbestos rope after a protective cover, and then laid with refractory bricks, and finally the surface of the continuous rail iron water scale shall be covered with river sand. In this way, a full range of multi-surface coverage is adopted for the continuous rail water scale. Fire performance is improved, but everyone knows that things are counterproductive. After the load cells on the continuous rail iron water scale are covered by multi-surface materials, the load cells always work in a closed, high temperature, and humid environment, making these load cells in place. In the “deep and hot” state, the insulation organization of the load cell on the continuous rail iron water scale is damaged and damaged quite seriously. After the load cell has been used for only 3 months, its comprehensive technical indicators and technical parameters have generally declined or even many of the sensors are directly damaged, resulting in frequent field failures and frequent replacement of the load cell.
The overhaul workload has doubled and the maintenance cost has risen, resulting in extremely unstable working conditions of the continuous rail iron water scale. The serious reality urges us to make technical improvements to the current status of this scale as soon as possible in order to meet the measurement requirements of molten iron produced by blast furnaces. Through on-site investigation and repeated observation and pondering, it was decided to adopt a new technical solution to improve the installation method of the original scale: first remove all the protective layers that originally covered the surface of the load cell, and use refractory mud to balance all the scales on the scale. The load cell and its cable surface are covered and protected. At the same time, the cable protection cover of the load cell is fully enclosed and covered with asbestos refractory material. The load cell on the continuous rail iron water scale is changed from the original fully sealed protective layer to ” The “bare” protection method avoids the reappearance of the insulation tissue damage of the load cell due to high temperature and humidity and the sealed protection method of the load cell in the past, and improves the service life of the weighing equipment. Now we have taken advantage of the opportunity of blast furnace ventilation to change all 16 “one tank to the bottom” continuous rail water scales at the bottom of the original blast furnace to “bare scale” operation. This has the effect of protecting the sensors and prolongs the use of continuous rail water balances. Life span plays a key role.
- Improve the original load cell line laying method
The blast furnace bottom “one tank to the end” continuous rail iron water scale on-site use environment is extremely harsh, so the surface protection of the load cell cable is also particularly important. When installing the continuous rail iron water scale equipment, due to lack of experience, we laid the signal cable bridge of the continuous rail iron water scale weighing sensor on the outside of the molten iron tank car track. After using it for a period of time, it was found that the molten iron sparks when the molten iron tank car was docked with the molten iron. It splashes around in a parabolic manner. Some residual molten iron or molten iron sparks often infiltrate from the sand on the ground surface and directly enter the line surface protection layer of the load cell. Eventually, the load cell line will burn out and cause continuous rail molten iron. Balance measurement interruption failure.
In response to this situation, first, the iron smelters are required to carry out careful management and careful operation to reduce and reduce the occurrence of “iron running” and residual molten iron weighing sensor cable burnout accidents;
The second is to improve the laying method of the load cell cable line on the original iron water scale, that is, to lay it on the inner side of the iron water tank car track. We use a 200×100 bridge to lay it and place it in the middle of the two tracks. Refractory bricks are placed on both sides of the bridge. All the load cells on the balance are exposed to the surface of the cable. First, wrap it with high temperature resistant asbestos rope to protect it. Cover with refractory mud. After laying the asbestos board above the bridge, it is also covered with refractory mud. The 8 sets of plug-type shear load cells and 16 sets of rail pad type load cells on the hot metal scale are covered with a protective cover and then covered with refractory mud to form a double layer of protection.
Improvement methods and effects: First, the use of bridge laying and wiring methods improves the progress of continuous rail iron water balance cable laying (originally galvanized pipes are used to lay the wiring), and at the same time, it is very convenient and fast to deal with the replacement or troubleshooting of the equipment on the scale.
Secondly, the track itself becomes a natural protective barrier (the molten iron sparks when the molten iron flows into the tank are sprayed in the parabolic direction, and the track is like a wall blocking the spray of molten iron sparks). The protective effect and effect of the weighing sensor circuit of the railway water scale are indeed effective. After a year of testing, it is confirmed that the protection effect of the circuit of the load cell is significantly improved after the improvement, which greatly reduces the circuit burn failure of the load cell.
- Improvement of the parking and positioning device of the blast furnace weighing molten iron tank car
- The establishment and application of early wheel fixed-point parking signs
Ningbo Goldshine Electronic Co., Ltd Company now uses two different methods of measuring the continuous rail iron water balance of the blast furnace. That is, the continuous rail iron water balance made by pure “plug pin shear force sensor”; the composite continuous rail iron water balance made by pure “plug pin shear force load cell” and “rail pad type load cell”. In the early stage, we set up a mechanical mark at the midpoint of the 600mm stopping distance and 1000mm interval of the stopping distance for these two different types of continuous rail water scales. At the same time, mechanical marks were also set on the boundaries of the two ends. Yilai Hot Metal Tank Truck
When the wheels are running, they can be controlled to stop and measure in the section where the mechanical mark has been set, so as to ensure the accuracy of the static weighing of the molten iron tank car at this time. Obviously, beyond the above-mentioned stopping distance (set interval), the weighing and measurement of the molten iron tank truck cannot be accurate. This relatively primitive method of fixed-point alignment of wheels, after a period of use, various drawbacks and inaccurate measurements have become prominent. This made the site doubt the use effect and application of this type of “one can to the end” molten iron scale. One is that the on-site logistics linkers are not accustomed to the use of this new type of iron water scale, so that it is difficult to accept it in reality; the other is that they do not understand the working principle of this type of continuous rail iron water scale, so the on-site wheel alignment depends entirely on The visual positioning of the wheels at fixed points, due to the large deviation of the position, resulting in inaccurate measurement, which affects the accuracy of weighing; third, when the iron ladle is docked with the molten iron at the tap hole, the logistics linker must confirm that the wheel is stopped at a close distance The accurate and effective position of the iron is bound to cause accidental personal injury to the on-site connector by the molten iron. Implementing as soon as possible to solve the technical problems of precise wheel positioning has indeed become a key element for the success of the scale’s application in Ningbo Goldshine Electronic Co., Ltd.
- Installation and application of intelligent recognizable wheel positioning device
In response to this subject, we organized personnel to carry out special technical research to further improve the on-site use conditions of the “one tank to the end” continuous rail iron water scale, and improve the technical requirements for precise wheel positioning. That is, continue to keep the mechanical signs available for on-site positioning (bars with conspicuous paint on the surface, firmly installed next to the parking signs set for the iron water scale). Weld an S-shaped vertical plate in the effective area of the fixed-point parking on the iron water scale (that is, on the inner side of the rail), drill a hole at a position above the vertical plate, and install the proximity switch in the hole of the vertical plate Fixed, the surface of the proximity switch is parallel to the inner side of the wheel, and a certain distance and interval are reserved. Install a sound and light alarm on the wall of the column where the weighing instrument cabinet is installed at the other end of the scene. Through a transmission cable in the middle, the proximity switch and the sound and light alarm are organically connected to form a whole The intelligent device that can recognize the wheel’s fixed-point alignment can be used for precise wheel positioning on site. In the on-site installation, the distance between the surface of the proximity switch on the S-shaped vertical plate and the inner side of the wheel and the setting of its height have a direct relationship and influence on the accuracy of its signal collection. The size of the S-shaped vertical plate is set too high, and it will be scraped off by the roadblock cleaner in front of the locomotive. It is very important to test and install repeatedly on site during use, so that the signals collected by the proximity switch can be transmitted in a timely and effective manner, and it is also very important to ensure that the S-shaped vertical plate is not scraped off by the roadblock clearer set in front of the car during use. . The working principle of the audible and visual alarm: Once the molten iron tanker enters the scale body and is ready for measurement, if the wheel’s fixed-point measurement position is deviated, the proximity switch will receive the signal, and the intelligent audible and visual alarm will emit a roaring sound. The roaring sound indicates the wheel There is a deviation in the precise positioning. Once the roaring sound of the sound and light alarm stops at this moment, the position of the fixed-point measurement at this time is accurate. The on-site logistics linker can judge that the molten iron tanker enters the best position of the molten iron scale for weighing and measurement based on the effect of the sound and light alarm.
In the past, the method of confirming the wheel alignment of the molten iron tanker by observing the on-site mechanical markings, the collection rate of the correct wheel alignment was about 60%, and now the intelligent method that can identify the wheel fixed-point alignment device is used, and the collection rate of the correct wheel alignment is increased to 95%. The device solves the technical problem of difficult wheel positioning of the molten iron tanker, ensures the accuracy of the blast furnace molten iron scale in use, and eliminates the personal injury accidents caused by the on-site logistics linker who had to confirm the accuracy of the parking space at close range in the past. The process measurement time is improved, and the production efficiency is improved. The device has been used in the field for more than one year and the effect has been good.
Fourth, the improvement of the drainage around the iron water scale
Because the blast furnace bottom continuous rail iron water scale is generally installed in low-lying areas, it is easy to cause water accumulation, leakage and flooding, so that the weighing sensor on the continuous rail iron water scale is in an environment that is extremely susceptible to damp and flooding. under. To this end, we have formulated the following measures:
Firstly, beside the installation of the continuous rail iron water scale for No. 1 and 2 blast furnaces, the civil works shall add drainage ditch to facilitate the groundwater energy in the section.
Directly diverted and drained, to achieve the purpose of protecting the load cell on the continuous rail iron water scale from damp and flooding damage;
Second, communicate with the iron smelting plant and require it to regularly dredge and clean the drainage ditch around the iron water balance, maintain smooth drainage communication, and avoid the occurrence of groundwater backflow;
Third, instruct ironmaking to strengthen process discipline during the maintenance of the blast furnace, and it is strictly forbidden to wash the swing nozzle above the tap hole with water to prevent water from directly falling into the weight sensor on the continuous rail iron water scale and causing damage. Ensure that the external environment of the load cell is always in a dry state.
Five, the transformation of the basic part
Under the long-term rolling of heavy metal tanker on the blast furnace tapping transport line, the track bed of the molten iron line loosens and sinks, causing the rail and the metering rail to not be on the same horizontal line, squeezing or tightening the iron water balance of the continuous rail, resulting in a continuous rail. Iron water scales sometimes produce weights of different tonnages without cars, resulting in measurement errors, which affect the accurate measurement of molten iron loading. According to this situation, we organize civil construction rectification and improvement on the part of the track bed at the connection between the iron wire and the rail scale. , That is, the two ends of the continuous rail iron water balance at the bottom of the blast furnace, each set up to 10
The quasi-hard track bed with a depth of 1 meter and a depth of 1 meter ensures that the foundations at both ends of the iron water scale will not settle during use, which has an effect on the stable operation of the continuous rail iron water scale.
And accurate measurement is essential. It has been implemented on two continuous rail iron water scales of 1 blast furnace, with good results, and the follow-up transformation work is progressing as planned.
- Other improvements
- Communicate with weighing equipment manufacturers and require them to continuously improve and improve the quality and life of sensors in terms of anti-aging, anti-fatigue, anti-high temperature and extreme conditions, and control the quality of subsequent weighing equipment and spare parts from the source. , To better serve and meet the needs of the production site of Ningbo Goldshine Electronic Co., LtdCompany.
- Continuously strengthen the training and improvement of employees’ own quality and business, through continuous learning and training, combined with the actual situation on the site, to explore and improve on-site equipment problems, to create a enthusiastic, skilled and efficient maintenance team.
Seven, concluding remarks
After continuous improvement, the operating stability of the 16 continuous rail iron water balance equipment in the blast furnace bottom of Ningbo Goldshine Electronic Co., Ltdhas been greatly improved, the failure rate of the equipment has been significantly reduced, and the service life and cycle of the weighing sensor on the scale have been increased and reduced. The loss of weighing equipment has been reduced, the maintenance intensity has been reduced, the direct installation efficiency of molten iron has been improved, and the economic benefit has been improved. The improvement and perfection of the installation method of the 16 blast furnace bottoms of Ningbo Goldshine Electronic Co., Ltdhas ensured the lean production of Ningbo Goldshine Electronic Co., Ltd. The steady operation.