一般接头结构的密封是在联接管的外表面压入硬钢密封环来实现的(图1(a))。当旋入螺母时,联接管的外表面便在密封环的前端边缘作用下形成环槽,它能起到密封和固定的效果。在接头制造精确和使用条件适当时,这种接头的可靠性和寿命是够高的了。但当不具备 General joint structure of the seal is welded to the outer surface of the pipe into the hard steel seal ring to achieve (Figure 1 (a)). When the nut is screwed on, the outer surface of the coupling tube forms a ring groove under the action of the front edge of the sealing ring, which can be sealed and fixed. The reliability and longevity of such joints are high enough when the joints are manufactured to the precise conditions of use. But when not available