文献翻译-反应釜用机械密封设计

第 1 页 共 9 页附 录 原文： Mechanical Seal Design Reactor Institute of Electrical and Mechanical Department of General Chen I. Introduction Agitated reactor is chemical, pharmaceutical production in one of the key equipment, its operating efficiency and reliability of the device depends largely on the merits of particular seal high-pressure high-temperature reactor shaft seal is currently the need for specialized solutions problem. China has been setting the standard kettle-type mechanical seal products, 201,202,203,204,205,206, the use of pressure 1 16kgf/cm, shaft diameter is 30 ll0mm. In recent years, with the petrochemical, pharmaceutical industry, stirred tank reactor reaction pressure, temperature gradually elevated, and the direction towards the development of high performance. Pollution prevention and safety from both, energy conservation point of view of the seal device reliability, longevity, leakage Quantity and economy and other requirements are also increasing. Therefore, the existing standard kettle with mechanical seals can not fully meet their requirements, up to the need to use specially designed working conditions. In this paper, a high temperature autoclave design of mechanical seal for a brief introduction. Second, the conditions given by the user Device: 300 liter vertical reactor, stirring shaft inserted from the top, single-bearing; Maximum working pressure; 25kgf/cm; Temperature: room temperature 15O Stirring speed: 12O 150rpm; Medium: dilute ammonia + dehydroacetate powder + solvent Biochemistry; Shaft diameter: 30mm, diameter length ratio: 1:50; Axial space: Kamaguchi coupling flange to the back side while the height is about 293mm; Operation: Intermittent operation, stopping frequently to open; Leakage: 3ml / h; Life: 8000 h (one year). Third, technical analysis and design According to the conditions and requirements of a given point of view, the mechanical seal is a very harsh operating conditions. The main problems involved: 1. Top loading autoclave technical problems with the nature of the mechanical seal pump mechanical seal completely different, because it is in the vapor space (only the material is liquid when the tank is full), seal prone to dry run. 2. As the medium is the chemical reaction within the reactor, pressure, temperature, material and shape change are always asked, in the stress cycle and the role of thermal cycles, the seal faces deform easily. 3. Mechanical seal used at room temperature, due to the friction surface of the heating and sealing of the mixing heat will seal the room temperature rise. When used at high temperatures, due to heat conduction within the tank, the temperature will further rise, causing friction surface of the liquid film evaporation, resulting in dry run, and to promote corrosion, accelerated aging auxiliary ring, resulting in deterioration in the short term sealing performance. 4. Stirring shaft inserted from the top vertical reactor, its diameter longer than large. It is a single support, the amount of its inevitable swing higher. 5. In the reaction process, the mixer blades and fluid material generated by relative motion between the vortex, must be caused by mixing shaft vibration. 6. May also occur for the following reasons axis traverse: (1) uneven or liquid feed is too low; (2) formation did not control the reactants, viscosity increases; (3) sudden changes in speed mixer; (4) thermal expansion or pressure and temperature fluctuate. 7. Because the top of the reactor very easy to install seal. Kettle mechanical seal in the structure must be easy to install and removal. In the past, mechanical seal failure resulting in performance, many of them are caused by poor installation of the reactor because the existing parts of mechanical seal to the reactor need to install one by one, we should ensure that its accuracy is difficult. According to the conditions given by the user and the technical analysis to determine the following basic design: 1. Higher use of safety barrier double end mechanical seal, to ensure the reactor sealed. 2. Sealed from the outside to enter the clean room suitable for the lubrication of cooling liquid resistance sealed, and set the cooling water jacket, to improve the sealing of the operating conditions 3. The structure of the sealing device, additional bearings to reduce shaft deflection and a rocky ledge. 4. Consider the ease of installation and removal, and economic factors. 4, structural design features According to the design of mechanical seal design, the friction pair material for the surfacing alloy carbon Graphite, supporting ring material: NBR a 4O. Specific technical measures; 1. Consider the pressure fluctuations in the design of the seal by 30kgf/cm. Side sealing surface of the upper atmospheric pressure to bear large, so designed as balanced, 30%, static method supports dual-ring seal 0-ring to reduce the static part of the deformation. Medium within the lower part of the lateral side of the sealing surface pressure is small, it is designed to be non-balanced. It is worth noting that this side of the seal may seem easy, in fact, not. If not handled properly cause leaks, pollution vessel will be within the material, resulting in product failure, we must give our full attention. Under static compression ring does not use the traditional structure, but with good use of the following floating-mounted so that the end is always the best fit to maintain the state. 2. Installation of a shorter axial dimension structure, because the seal and spring seat sharing a drive. With a sleeve on the keyway and fixing screw to drive the drive seat, sturdy and reliable 3. The structure of the seal bearing added to improve the dynamic stability of the mixing shaft (measured at the tank flange runout of the shaft 0.05mm). Mechanical seal from the bearing mounted close to the place, thus enhancing the sealing operation stability. 4. Offices in the sealed chamber cooling water jacket to reduce heat from the reactor body to pass chamber. 5. Introduced to the sealed chamber from an external sealing liquid, on the mechanical seal lubrication, cooling and block letters. 6. The seal structure has a fast and accurate installation and removal of benefits. The seal as an integrated whole, can be pre-assembled, and tested, and then loaded on to the kettle, do not need to re-adjust. If the seal fails, the entire seal can be removed, the pre-assembly, debugging can be a good backup seal fitted. Therefore, the installation, maintenance and replacement is very convenient, stopping at the same time greatly reducing the time, with obvious economic Benefits. 5, sealing liquid system For the reactor with double mechanical seal, the sealing performance and stability to make long working life, the key is to use proper sealing liquid system. On the basic requirements of sealing liquid system is to ensure the safe operation of seal, namely: 1. Under a certain pressure, to send the seal on the sealing liquid to maintain the liquid film between the friction surface and form a barrier between the material and the atmosphere to ensure that materials not leak fluid. 2. Closed loop liquid circulation should be sufficient to take away the heat generated by friction surface and by stirring shaft or container to avoid the conduction of heat to the sealing device. 3. Ensure that the Kettle is always in proper operating condition. The design of the sealing liquid pressure control system uses both methods, that is, the top pick out of a kettle body 1-inch pipeline to a pressure tank top. Pressure tank installed in the sealed room above the 2 m Department. Sealing liquid seal chamber exit at the highest point of the water jacket, thermal siphon effect to achieve the purpose of the cooling cycle. The volume of pressure tank 2O liters, made of stainless steel. The peripheral cooling jacket, heat transfer area of 0.02 square meters, to prevent the sealing liquid temperature oxidation and deterioration. Pressure tank to the highest pressure 30kgf / c . Set obituary. Attachments are used in pressure gauge, liquid level meter, and thermometers, exhaust valve and drain valve, liquid filling the mouth and so on. Sealing liquid with dilute glycerol (glycerin, and soft water of 50%), once every three months to replace. Because the system uses thermal siphon method, a simple economy, the pressure changes inside the reactor to follow, and can ensure that the seal fluid pressure within the pressure slightly higher than the kettle. VI Conclusion Chemical, pharmaceutical production in stirred tank reactor, the leakage demanding. If excessive leakage will result in product failure or shutdown, so the need for effective and reliable seal device. Practice shows that the mechanical seal to meet their requirements. This article describes the reaction vessel with a mechanical seal for a chemical plant in Anhui design. Since the on-site installation of the seal after the sealing performance and stability, leakage is extremely small, life nearly two years, still continue to use. 反应釜用机械密封设计 机电部通用机械研究所 陈德才 一、前言 搅拌式反应釜是化工、制药生产中的关键设备之一， 其运行效率和可靠性很大程度上取决于轴封装置的优劣 尤其是高压高温反应釜的轴封是当前需要专门解决的问题。 国内已定型的标准型釜用机械密封产品有 201、 202、 203、 204， 205、 206型， 其使用压力为 116kgf cm ， 轴径为 30 ll0mm。近年来， 随着石化、制药工业的发展， 搅拌反应釜的反应压力、温度随之增高， 并向着高性能方向发展。同时从防止污染以及安全、节能等角度出发，对轴封装置的可靠性、寿命、泄漏量和经济性等方面的要求也越来越高。因此，现有的标准型釜用机械密封产品已不能完全满足其要求， 达就需要根据使用工况进行专门设计。本文就一种高温高压反应釜用机械密封的设计作一概要的介绍。 二、用户给定条件 装置： 300立升立式反应釜， 搅拌轴从顶部插人， 单支承； 最高工作压力； 25kgf cm ； 温度：室温 15O 搅拌速度： 12O 150rpm; 介质：稀氨水 +脱氢醋酸粉料 +生物化学溶剂； 轴径： 30mm， 径长比： 1： 50； 轴向空间 : 釜口法兰至联轴节背端而高度约为 293mm; 操作方式： 间歇操作， 开停频繁 ; 泄漏量 :3ml h; 寿命 : 8000 h (一年 )。 三、技术分析和设计思想 根据给定的条件和要求来看， 该机械密封的运转条件是相当恶劣的。所涉及的主要问题是 : 1顶装釜用机械密封的技术问题性质完全不同于泵用机械密封， 因为它是处于气相空间中 (只有物料为满釜时才是液相 )，密封易出现“干运转”。 2 由于介质是在釜内进行化学反应， 压力、温度、物料的形态等都是随时问而变化的， 在压力循环和冷热循环的作用下， 密封端面易产生变形。 3.机械密封在常温下使用时， 由于摩擦面的发热和密封的搅拌生热会使密封室内温度上升。在高温使用时， 由于釜内的热传导， 将使温度进一步上升， 从而引起摩擦面的液膜汽化， 产生“干运转” ， 并促进腐蚀， 加速辅助密封圈老化， 致使密封性能在短期内恶化。 4搅拌轴从顶部插人立式反应釜，其径长比大又是单支承，其摆动量必然较大。 5在反应进行的过程中， 由搅拌器浆叶和流体物料之间的相对运动所产生的涡流，必定要引起搅拌轴的振动。 6 由于下列原因还可能出现轴的窜动： (1)进料不均或液面太低； (2)反应物生成没有控制好， 粘度增高； (3) 搅拌器的速度突然变化； (4)受热膨胀或压力和温度产生波动。 7 因为在反应釜的顶部安装密封很不方便。在釜用机械密封的结构方面， 必须便于安装和拆卸。以往， 机械密封在性能方面产生的故障， 有很多是因安装不良而造成的 因为现有的釜用机械密封的部件需要逐个安装到反应釜上， 要保证其精度很困难。根据用户给定的条件和上述的技术分析，确定下述基本设计思想： 1采用安垒性较高的双端面机械密封装置， 以保证反应釜的密封性。 2从外部向密封室输入清洁适宜的润滑冷却液体进行阻封， 并设置冷却水套， 以改善密封的运行条件 3在密封装置的结构中增设轴承， 以减小轴的偏摆和窜动。 4考虑便于安装和拆卸以及经济性等因素。 四、结构设计特点 根据上述设计思想设计的机械密封装置，其摩擦副材料为堆焊硬质合金对碳 石墨， 辅助密封圈材料：丁晴一 4O。 具体技术措施； 1考虑压力的波动，该密封按 30kgf cm 设计。上端大气侧密封面所承受的压差大， 因此设计成平衡