(Continued from the previous period) 2 Use of compressed air 21 Advantages of compressed air Because compressed air has the following characteristics, it is widely used in various fields of industry and the tire industry. ) It can easily store large-capacity compressed air as needed;) Simple design and control, simple with pneumatic control automatic control system;) Pneumatic components are easy to realize linear and rotary motion of stepless speed regulation;) Mainly compressed air The production cost is the operating cost of the air compressor and the depreciation of the equipment. The cost of the whole set is lower, so the operation and maintenance costs are lower.) The pneumatic components are suitable for the price and have a long working life, so the system has high reliability; Compressed air is largely unaffected by high temperature and dust corrosion, and has strong adaptability to harsh environments. This 1967-), male, senior engineer, graduated from Qingdao Institute of Chemical Technology in 1989, majoring in rubber machinery, mainly engaged in rubber machinery. The design, management, and organization and management of tire production have published 20 papers.
One point is that other media can't compare;) Pneumatic components are clean and have special exhaust air treatment methods, which have less environmental pollution;) Compressed air does not cause fire in dangerous areas; if the system is overloaded, the actuator will only stop. Or slipping, its safety performance is better.
22 tire factory requirements for compressed air tire factory requirements for compressed air can be divided into the following aspects of pressure requirements. Depending on the requirements of the process, the pressure of the compressed air is required in any process for producing the tire, wherever compressed air is required. In actual use, the required pressure of the compressed air must be met. If the pressure is too low, the force required to generate pressure by the compressed air is not achieved; on the contrary, if the pressure is too high, the equipment or the actuator may be easily damaged. ) Traffic requirements. Where compressed air is actually used, there is also a requirement for the flow of compressed air, and the flow rate should be matched to the needs. If the flow rate is too small, the speed of the flow rate of the compressed air will not be reached; on the contrary, if the flow rate is too large, the corresponding speed will be too fast, not only an unsafe factor, but also a waste of compressed air.
Dryness (ie water content or dew point temperature) requirements. Different processes and processes for tire production have different dew point temperature requirements for compressed air. In most cases, it is sufficient to require a dew point temperature of compressed air above 0C. The dew point requirement for compressed air is usually achieved by a dryer. In the process of tire production, the processes of carbon black conveying and tread blowing require high dryness of compressed air.
Cleanliness requirements. This is a requirement for the quality of compressed air. It is relatively complicated, and it is required that the solid matter, oil mist, microorganisms, harmful gases, etc. in the compressed air cannot exceed the prescribed range. To achieve the cleanliness requirements, it is generally done by a device such as a compressed air filter or an oil mist separator.
2.3 Use and management of compressed air in tire factories Compressed air is required in all processes of tire production to achieve different purposes.
21 rubber mixing process In the rubber mixing process, the compressed air is mainly used for carbon black conveying, the action of the upper and lower plugs of the internal mixer, the drying of the film after soaking the release agent, and the operation of the pneumatic components.
When carbon black is transported and pneumatic components are operated, the compressed air must be dry, clean, and pressure stable. This requires that the air system must be equipped with an air adsorption dryer or a refrigerated dryer, and a gas storage tank of appropriate volume should be installed, so as to ensure that the nozzles and pneumatic components of the pipeline are not easily blocked and the carbon black is smoothly transported. When the carbon black is transported, the pressure adjustment of the carbon black pressure feeding tank and the sump bucket must be appropriate, so as to ensure the positive pressure conveying of the pressure feeding tank and the negative pressure traction of the sump; the ultra high pressure should be alarmed in time to avoid the pressure of delivery. Too high causes a carbon black spray can or a blocked pipe.
The action of the upper and lower plugs of the internal mixer and the compressed air used for drying the film after soaking the release agent should ensure that the pressure is stable and the flow rate is appropriate. If the flow rate is too small, the residual liquid of the release agent on the film surface will not be cleaned; if the flow rate is too large, not only the waste of compressed air will be caused, but also the film may be easily adhered.
Unstable pressure will cause the speed and pressure of the upper and lower top bolts of the mixer to be inconsistent, which will have a certain impact on the normal operation of the equipment and the quality of the rubber compound. In the rubber mixing, the top bolt of the internal mixer must meet the specified pressure, so the diameter of the upper top wind cylinder is larger. At the same time, since the upper plug is to be used for several times during a rubber mixing cycle, the air volume of the upper plug is relatively large. In order to save compressed air, the upper plug control system can be modified to partially recover compressed air. The specific method is as follows: one set of one-way valve group is added to the rising and falling pipelines of the upper top bolt, and the compressed air discharged by the upper top bolt during ascending and descending is respectively entered into the opposite by the pressure difference in the upper plug cylinder. In the cylinder, the intake air is stopped when the pressure is close, and the compressed air of the pneumatic system is used to complete the related action, which can save about 25% of the compressed air, and can reduce the noise of the compressed air during discharge.
21å“2 Calendering and pressing process In the rolling process, compressed air is mainly used for the execution of pneumatic components, as long as the pressure and flow rate are appropriate.
In the extrusion process, the compressed air is mainly used for tread drying after drying or spraying in a cooling water tank, and execution of pneumatic components. The compressed air used for tread drying must be clean, dry, and free of oil, water, or other contaminants to prevent segregation during tread use. In addition to cleaning, the compressed air used in pneumatic components requires pressure and flow to be stable to ensure the accuracy of the pneumatic components. To this end, a gas storage filter can be added to the pneumatic system to meet the requirements of use.
21å“3 molding process In the molding process, compressed air is widely used in horizontal cutting machines, vertical cutting machines/multi-knife slitting machines, wire loop wrapping machines, layer laminating machines, tire building machines, etc. Compressed air is required on the top, some for power, and some for pneumatic components.
For horizontal cutting machine, vertical cutting machine / multi-tool longitudinal cutting machine, etc., it is mainly used in the action of the rodless air cylinder and pneumatic components. It is required that the compressed air must be clean, free from impurities, and the pressure and flow rate are stable to ensure no The rod cylinder and pneumatic components operate normally.
For the wire loop wrapping machine and the layer cloth laminating machine, etc., the compressed air is mainly used to generate pressure on the air cylinder, and the steps of the wire loop wrapping and the layer cloth bonding are completed.
For the tire building machine, it is mainly used in the curtain drum spreader, the forming rod air cylinder, the positive wrapping machine, the lower pressing roller, the rear pressing roller, etc., and the compressed air flow rate and pressure must be stabilized. When the curtain spreader is in operation, the compressed air used should not contain impurities such as oil and water to avoid isolation between the plies during molding.
In order to meet the requirements of the molding machine, a set of filter and n tank can be added to the pneumatic system.
2.3.4: Vulcanization process The process of compressed air is mainly used for the shaping of green tires, the cooling of tires after vulcanization and the control of pneumatic components. In the air setting machine, the pair of blanks is shaped, and the compressed helium is required to be stable except for the pressure. In addition, the flow rate should be ensured to make the rubber and the curtain fully stretched when the blank is set. D5/a7.274) 1 = 3600f / K for integration, when measuring the incompressible fluid, the instrument constant can be directly placed into the parameter to calculate. Now used to measure compressed air, the instrument constant must be converted, that is, the ratio of the instrument constant K to the compression factor and m is put into the parameter, and the volume flow rate under standard conditions is obtained.
Before commissioning and debugging, check whether the flow direction of the sensor is consistent with the flow direction of the compressed air in the pipeline, whether the connection between the sensor amplifier board and the flow totalizer is correct, and whether the power line connection is reliable, especially the grounding wire of the instrument should be connected with the instrument case and the pipe. To eliminate external interference.
After all the work checks are correct, debugging can be performed. When debugging, use a general purpose oscilloscope as the debugging instrument. Compressed air is introduced into the pipeline, and the valve is adjusted to reduce the flow rate, generally 10%~20% of the range. Adjusting the potentiometer W1, as shown in 圄3, makes the amplifier magnification appropriate. Adjust the trigger sensitivity potentiometer W2 so that it does not increase or drop the wave, see 圄 4. Re-adjust the valve so that there is no waveform output when the flow rate is zero. After the adjustment is completed, it can be put into trial operation.
After the indication error adjustment vortex flowmeter is put into trial operation, the effect is better from the use situation, the data is stable, and the instrument has no fault. However, by analyzing and comparing the measured data, it is found that the instrument error is large. To this end, we use the oscilloscope to detect the amplifier and find that there are wave-increasing and wave-dropping phenomena in the amplifier. This is due to improper adjustment of the amplifier trigger level. By adjusting the trigger sensitivity potentiometer W2 to make the amplifier output the correct waveform, we re-commissioned as follows. Close the valve so that there is no compressed air flowing in the pipe. The instantaneous flow rate of the flow totalizer should be zero, and the accumulated value is unchanged. If the pipe is tapped with a wooden block, the instantaneous flow has a slight change and disappears instantly. normal. Adjust the valve so that the compressed air flow in the pipeline is generally 10%20% of the range, observe whether the output waveform is normal; if not, adjust the trigger sensitivity potentiometer W2 so that it does not increase and drop the wave; When the flow rate is zero, there should be no waveform output. The amplifier works fine at the lower limit range. After adjusting the valve to make normal flow compressed air into the pipeline, the detection amplifier outputs a square wave pulse signal, indicating that the indication value of the instrument corresponds to the change of the actual flow rate. When stabilized at a certain flow rate, the instantaneous flow indication is stable and no sudden Jumping high and low, the oscilloscope observes the waveform is normal, then the amplifier works normally.
After the adjustment was completed, it was put into operation again. After data analysis, it was confirmed that the problem was solved.
Since the use of the vortex flowmeter has been evaluated and compared, we believe that the use requirements have been met. Because we are located in the north, the temperature changes greatly in winter and summer, which has a certain influence on the measurement data of the vortex flowmeter. However, after we explored the law, the instrument parameters were adjusted according to the changes of the ambient temperature in winter and summer, and the measurement data was basically stable and reliable.
Our company is now equipped with 16 vortex flowmeters, the use situation is relatively stable, the failure rate is very low, only some simple maintenance can be done, basically achieving long-term, high-precision operation. Through careful analysis of the measured data, we have developed a more scientific and reasonable index of compressed air consumption quota test, laying the foundation for standardizing energy management, reducing energy costs and improving economic efficiency.
4 Conclusion Because of its own characteristics, the use of compressed air is more common. In the production process, due to the simple production of compressed air, various enterprises have some problems in terms of compressor configuration, operation control and pipeline laying, which affect the production cost of compressed air. Compressed air is colorless and odorless, and is not easy to find after leakage. There is also a phenomenon of waste and recycling, which results in unsatisfactory use of compressed air. How does the measurement of compressed air serve the management of enterprises and test children? There is more work to be done. If these problems are solved well, the cost of energy consumption will be reduced invisibly and the management level of the enterprise will be improved. On the contrary, if these problems are not taken seriously or handled badly, the cost of energy consumption will increase and it will be detrimental to the enterprise. Management and test children. Therefore, how to produce compressed air at the lowest cost, use and manage compressed air with the best effect, and measure the compressed air in the most scientific way is a problem that every tire factory always pays attention to and controls.
Of course, the views in this article are only the results that the author has observed in the work and some work done, not necessarily correct or comprehensive, only for peers. If it is inconsistent with the relevant principles or opinions, please feel free.
The four-drum all-steel radial tire one-time forming machine was successfully developed in Tianjin Saixiang Company. On June 1, 2005, Tianjin Saixiang Technology Co., Ltd. developed the first four-drum type with independent intellectual property rights to fill the blanks at home and abroad. All steel engineering radial tire one-time forming machine, and successfully produced the first 23.5R25 all-steel engineering tire. The equipment can complete one molding from 23.5~33 all-steel radial tires, processing one every 25min, which is more than double the efficiency of the original two-drum molding machine. In order to ensure the processing precision of the tire, the machine adopts a series of high-tech integrated with opto-mechatronics, and the overall level has reached the international advanced level.
The Shuguangyuan Inspection Center has been recognized by the Chinese laboratory. China National Rubber Group Shuguang Rubber Industry Research and Design Institute Chemical Industry Special Tire Quality Supervision and Inspection Center has passed the examination and approval of the China National Laboratory Accreditation Committee and obtained the certificate of accreditation. This indicates that the special tire inspection center has obtained the qualification of the national special tire quality supervision and inspection institution, and has the ability of supervision, appraisal, arbitration and commissioned inspection.
The special tire inspection center has advanced testing of aviation tire dynamic simulation testing machine, RW860 tire performance testing machine imported from abroad, electronic speckle tire nondestructive testing instrument, ozone aging tester, tire static balance testing machine, rubber processing analyzer, etc. Equipment, can undertake dynamic simulation test, static performance test and rubber and tire of civil aviation tires, military aviation tires, refurbished aviation tires, military vehicle tires, artillery safety tires, tank load wheels, aircraft wheel brakes, automobile tires, etc. Chemical analysis of raw materials, physical property testing and testing.
Prior to this, the Special Tire Inspection Center was the representative of the CAAC Aircraft Parts Test Appointment Unit and passed the Airworthiness Review of the Federal Aviation Administration (FAA) and the Metrology Accreditation Administration of the National Certification and Accreditation Administration.
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