农村煤改气户外燃气管道螺纹连接分析

Analysis on Threaded Connection of Rural Coal-to-gas Outdoor Gas Pipeline

根据现行标准,低压燃气管道应采用锥/锥形式的螺纹连接。通过调研多家燃气企业,发现燃气管道的螺纹连接在实际应用中普遍存在管件选型不当、现场加工螺纹要求不明、密封填料选用不当等问题。针对管道螺纹连接进行理论分析,计算DN 50 mm镀锌钢管螺纹的理论最小机紧圈数与上紧至材料屈服的圈数。分析螺纹牙高、牙型角、螺纹锥度加工误差对螺纹密封间隙的影响,从理论上说明了螺纹连接使用填料、上紧等措施实现密封的必要性。针对存在的问题,提出了解决措施,包括丰富设计文件细节、定期检验螺纹现场加工成品误差、选用合适的螺纹密封材料、规范施工方法。

According to the current standards,low-pressure gas pipelines should be connected by cone/cone thread. Through the investigation of many gas enterprises,it is found that improper selection of pipe fittings,unclear requirements for on-site machining of threads and improper selection of sealing packing are common problems in the practical application of threaded connections of gas pipelines. The theoretical analysis of the threaded connection of pipelines is carried out,and the theoretical minimum number of tight turns of DN 50 mm galvanized steel pipe thread and the number of turns until the material yields are calculated. The influence of thread height,profile angle and thread taper machining error on thread sealing clearance is analyzed,and the necessity of sealing threaded connection with packing and tightening is explained theoretically. In view of the existing problems,the solutions are proposed,including enriching the details of design documents,regularly inspecting the error of finished products on site processed,selecting appropriate thread sealing materials and standardizing construction methods.