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电动高温蝶阀为了满足高温的要求,必需要满足的要求有哪些
1. Material of valve body. The valve design standard is ASMEB16134. The number of pressure grades at room temperature calculated by the pressure-temperature meter in this standard is the design benchmark and the minimum wall thickness is calculated accordingly. In the design process, the valve body material is also selected as the material specified in ASMEB16134 standard, and the applicable temperature of the material is higher than the maximum temperature of the valve operating condition. After consulting the use of a large number of valve equipment materials in similar working conditions at home and abroad, 304H with high cost performance was selected as the valve body material in combination with the experience of using high temperature materials. This material can reduce the effect of creep on the material.
2、阀杆材料。根据高温强度估算,奥氏体钢在704℃的高温工况下,强度降低6415%以上,如果采用加大阀杆直径提高其强度的方法,则超出阀门结构要求,因此奥氏体钢不适宜做阀杆材料。lnconelX-750在704℃的高温工况时,强度降低4113%,但强度值还很大。根据屈服强度,并考虑持久强度计算得到的阀杆直径,符合阀门结构要求,因此阀杆材料选用lnconelX-750。
2. Stem material. According to estimate, the high temperature strength of austenitic steel at 704 ℃ high temperature conditions, strength decrease by more than 6415%, if adopt the method of increasing stem diameter increase its strength, is beyond the valve structure, therefore the austenitic steel is not suitable for stem material. LnconelX - 750 in the working condition of the high temperature of 704 ℃, 4113% lower strength, but strength value is very big. The stem diameter calculated according to the yield strength and considering the endurance strength is in line with the requirements of valve structure, so the material of stem is lnconelx-750.
3. The minimum wall thickness of valve body is calculated to ensure the integrity of valve pressure boundary. The minimum wall thickness is calculated by the regular method, and the calculation standard is ASMEB16134. When selecting the pressure-temperature rating, there are two kinds of pound level selection methods. One is to select the standard scale, and the calculated minimum wall thickness is relatively large and relatively safe. The other is to select the special pound scale, and the calculated minimum wall thickness is smaller than the standard pound scale, but the nondestructive testing requirements are strict. According to the experience of the design of the high temperature condition, choose the form of the combination of these two class, i.e. when calculating the minimum wall thickness of the pressure-temperature ratings, the class selection standards, and the body of nondestructive testing requirements according to the special class.
阀门泄漏率要求为最大流量的0167%,当泄漏超标就会引起系统烟机不能正常停车,从而造成重大事故。普通烟气蝶阀阀体通道内没有阀座,阀瓣仅起调节烟气介质流量的作用,不起密封作用。根据性能要求,大口径高温蝶阀设有阀瓣和阀座密封副,对阀门的流通性能、密封可靠性和启闭力矩3个方面进行了设计研究。首先按常规蝶阀设计了密封副,此形式密封可靠,虽然阀瓣旋转中心与密封面存在偏心力矩,使启闭力矩增大,但经过计算,力矩也在可以接受的范围之内。
The valve leakage rate is required to be 0167% of the maximum flow. When the leakage exceeds the standard, it will cause the system smoke machine to fail to stop normally, resulting in major accidents. There is no seat in the body channel of ordinary flue gas butterfly valve, and the disc can only regulate the flow rate of flue gas medium, not seal. According to the performance requirement, the large-caliber high-temperature butterfly valve is equipped with disc and seat sealing pair, and the design of valve flow performance, sealing reliability and opening and closing moment are studied. First of all, according to the conventional design the seal butterfly valve, this form of reliable sealing, although the disc rotation center and the sealing surface exist eccentric torque, make open-close torque increases, but after calculation, torque is within an acceptable range.
此结构的缺点是流通性能差,不能满足全开截面积的设计要求。经过反复设计、修改和计算,完成了对开式阀座密封副设计该阀座是2个半圆阀座,它们前后错开与阀瓣呈对称式分布,使得阀瓣能够设计成对称式流线形结构,使阀门具有良好的流通性能,从而满足了全开截面积要求和全开Cv值要求。由于阀瓣结构对称,所以启闭力矩较小。虽然其密封面某一处可能有泄漏现象,但只要合理控制阀瓣和阀座的尺寸精度、形位公差和二者之间的装配误差,就能有效控制泄漏率在合格范围之内。
The disadvantage of this structure is that it has poor circulation performance and cannot meet the design requirements of full open section area. After repeated design, modification, and calculation, completed the design for the open seat sealing set the seat is two semicircle seat, before and after they stagger and disc distribution is symmetric, enables the valve to designed to symmetric streamlined structure, improves the performance of the valve has good circulation, so as to meet the requirement of fully open cross-sectional area and full open Cv value requirements. Because the disc is symmetrical, the opening and closing moment is small. Although its seal face a certain place may have leakage phenomenon, but as long as reasonable control valve disc and seat size precision and shape tolerance and the assembling error between them, can effectively control the leakage rate within the acceptable range.
4、高温填料填料选用柔性石墨。其在空气中氧化温度为450℃,并在此温度下每24h后质量减轻1%。温度越高,质量减轻得越多,氧化现象越严重。柔性石墨填料最高使用温度为650℃,且仅用于非氧化介质。考虑到填料在填料函内处于压紧密封状态,只有一部分与空气接触,有资料介绍处于这种状态的填料使用温度可达816℃。电动高温蝶阀的研制,主要是解决阀体主体材料的选用、蝶阀密封副结构及阀杆密封结构的设计等问题,并通过试验选取了超高温填料,为石化行业催化裂化装置系统用阀门的设计和制造。
4. Flexible graphite is used for high temperature packing. Its oxidation in air temperature is 450 ℃, and at this temperature every 24 h after quality to reduce 1%. The higher the temperature, the lower the mass, the more severe the oxidation. Flexible graphite packing maximum temperature of 650 ℃, and only used for the oxidation medium. Considering the packing in a pressure tight seal state within the stuffing box, only part of it is exposed to air, packing with data is introduced in this state use temperature is 816 ℃. The development of the high temperature electric butterfly valve, mainly to solve the body material selection of the main body, the structure of the butterfly valve sealing pair, and the problem of the design of the stem seal structure and the selection of the ultra high temperature through tests packing, catalytic cracking unit for petrochemical industry system in design and manufacture of the valve.