| 摘要 |
1337794 Pressure vessel closures; screw threads NATIONAL FORGE CO 6 Jan 1971 [11 June 1970] 645/71 Headings F2P and F2Q A closure for a high pressure vessel comprises female and male threads 12, 14 the thread forms 16, 18 being machined so that when the vessel is unpressurized the load bearing surfaces of the male and female threads are spaced apart by a variable clearance that decreases from the interior to the exterior of the vessel. The variable clearance is selected so that when a predetermined pressure is generated within the vessel substantially all of the load bearing surfaces of the male and female threads are in contact (Fig. 2, not shown) the arrangement providing for a substantially uniform stress in the threads. In the embodiment shown in Fig. 1 the variable clearance is provided by progressively relieving the load bearing surface of one or both threads. Alternatively (Fig. 3, not shown) the thread form of the male member may increase in pitch and decrease in thread root diameter towards the interior of the vessel.
|
