| 摘要 |
<p>The same size and weight of tubular products, but in different grades of material, are made for universal connection but with seal areas that differ appropriately for adequate sealing without overstressing the connection members for the pressures encountered where each tubular length is put in service. The angle of the conically tapered seal on all box members (7) is made the same for all grades of the products. The pin member (10) of medium grade is made with an equal length seal area (16) and adjacent contacting area (11) on its forward end. The pin member (10) of higher grade is made with a longer length seal area than its adjacent contacting area. The pin member of lower grade is made with a shorter length seal area than its adjacent contacting area, thereby also placing the seal area further from the pin member distal end. This effectively forms a nose extension on the pin member (10) which stiffens the pin member (10) of lower grade and enhances the conical seal area forward of the first thread, which seal is spaced at a distance from the distal end by a non-sealing nose extension that is at least as long as the sealing area. The integrity of the seal is improved, the bearing surface is enlarged and the tendency of galling is reduced.</p> |
