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特大口径全焊接球阀的设计及密封结构改进

作者:完美论文网  来源:www.wmlunwen.com  发布时间:2019/10/31 9:23:25  

摘要:公称尺寸(DN)≥1400mm的球阀称为特大口径球阀,其口径超出国家标准的适用范围,设计时没有标准可参照,依靠对比分析设计,这样会加大成本、设计周期延长,不能保证经济性。

为了保证阀门在长时间内安全运行,本课题主要以城市供暖用PN2.5MPa的长输管线特大口径全焊接球阀为例,基于压力容器分析设计方法和先进有限元数值模拟技术,进行长输管线特大口径全焊接球阀的设计研究,研究的主要内容如下:

(1) 根据城市供暖用长输管线特大口径全焊接球阀的工作条件,参照美国API-6D-2014(24版)《管线和管道阀门规范》及GB/T 12224-2015《钢制阀门一般要求》等规范要求,根据长输管线全焊接球阀自身结构特点融入轻量化等设计理念,进行全焊接球阀球体、阀体、阀杆等零部件结构及尺寸的确定,密封结构设计。

(2) 采用压力容器分析设计方法(Designby analysis),基于ANSYS有限元分析软件,对不同工作状态下特大口径全焊接球阀的应力强度、刚度以及阀座密封圈与球体接触应力进行分析。分析结果表明刚度符合设计要求,对应力进行线性化后,依据JB4732-2005《钢制压力容器—分析设计标准》,对设计的特大口径全焊接球阀进行强度评定,强度满足设计要求,但阀座密封圈位置的操作密封比压较小,不能满足密封性能要求,需要对密封结构进行改进。

(3) 分析密封比压较小的原因,密封圈采用双斜面与球体接触的结构,并进行密封性能的分析。结果表明:结构改进后,球阀的密封圈处的操作密封比压提高了,由原来的最大值6.32MPa,提高到14.54MPa,接近许用比压值,可以保证密封。

(4) 通过实验设备,对设计制造的特大口径全焊接球阀进行压力试验、密封测试。实验结果表明:阀体结构的强度满足要求,无结构损伤,通过密封测试,无可见泄漏。

Ball valves with a nominal size (DN) ≥1400mm are called super-caliber ball valves, and their calibers are beyond theapplicable range of empirical formulas in national standards.There are no standards to refer to when designing, and experimentalstudies on mega-calibers are conducted and comparative analysis and design areperformed. The cost and design cycle of large-scale investment are prolonged,it can not guarantee the economy. 

In order to ensure the valve safe operationfor a long time, this project mainly takes the PN2.5MPa large-diameterfully-welded ball valve for urban heating as an example.Based on the pressure vessel analysis and design method and advancedfinite element numerical simulation technology, the design and research of thelarge-diameter fully welded ball valve for long-distance pipelines is studied.The main content is as follows:

(1) According to the working conditions ofthe large-diameter fully welded ball valve for long-distance pipelines forurban heating, refer to the specifications of API 6D-2014 (24th Edition)Pipeline and Pipeline Valve Specification and GB/T 12224-2015 Generalrequirements for industrial steel valves, etc. According to the long-distancepipeline full welded ball valve structure characteristics into the lightweightand other design concepts, all welded ball valve ball,valvebody, valve stem and other parts of the structure and size of thedetermination, sealing structure design.

(2) Using pressure vessel analysis designmethod (Design by analysis), based on ANSYS finite element analysis software,analysis the stress strength, stiffness, contact ring and spherecontact stress of the super-caliber fully welded ball valve under differentworking conditions.The results show that the stiffnessmeets the design requirements. After the stress is linearized, according toJB4732-2005 Steel Pressure Vessels-Design by Analysis,the strength of the designed large-diameter fully welded ball valve isevaluated. The strength meets the design requirements,butwhich does not meet the sealing performance requirements,and the seal structure needs to be improved.

(3) Analyze the reason cause the sealpressure is relatively small,the seal ring adopts the structurethat the double-side face contact with the sphere,andanalyze the sealing performance. The results show that: after the structure isimproved,the operation seal specific pressure of thesealing ring of the ball valve is increased, from the original maximum of5.66MPa to 14.54MPa,which is close to the allowablespecific pressure value, and can guarantee the seal performance.

(4) Through experimental equipment, Thepressure test and sealing test are carried out on the design and manufacture ofthe large-diameter fully welded ball valve.Theexperimental results show that: the strength of the valve body structure meetsthe requirements, no structural damage is found, and no visible leakage isobserved through the seal test.

关键词:轻量化设计;线性化分析;密封结构改进;无结构损伤;无泄漏

Lightweight design;Linearizationanalysis;Sealing structure improvement;No structural damage;No leakage

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