Patent Number: 047284790
Section: claims

1. A high pressure seal fitting with a built-in low pressure seal arrangement for sealing a space defined by an inner diameter of a pipe and a rod slidably disposed within the pipe and extending beyond an end of the pipe, said fitting comprising: a fitting body provided with an axial passage for slidably accommodating the rod and having a first and region constructed for engaging the end of the pipe for forming a high pressure seal between the pipe and said fitting body, and a second end region opposite said first end region and including an outer circumferential protrusion having the shape of a ferrule for cooperating with components utilized to form a releasable high pressure compression seal; and  low pressure seal means disposed in the axial passage at said second end region of said fitting body for maintaining a low pressure seal between said fitting body and the rod when said releasable high pressure seal is disconnected, said fitting body being disposed radially intermediate said releasable high pressure compression seal and said low pressure seal means. 2. A fitting according to claim 1, wherein said fitting body has an inner surface defining the axial passage and said low pressure seal means comprises a flexible ring disposed in the axial passage at said second end region for filling a space defined by said inner surface and the rod, and compression means for compressing said flexible ring for forming the low pressure seal. 3. A fitting according to claim 2, wherein said compression means includes a seal nut, threads provided at said second end region for engaging said seal nut, and a first annular abutment provided on said inner surface at said second end region between said threads and said first end region, said first annular abutment providing a stop for said flexible ring which can be urged against said first annular abutment by appropriate rotation of said seal nut via said threads. 4. A fitting according to claim 3, wherein said first annular abutment is formed by an annular recess in said inner surface. 5. A fitting according to claim 3, wherein said low pressure seal means includes a seal washer disposed between said flexible ring and said seal nut. 6. A fitting according to claim 5, wherein said inner surface includes a second annular abutment between said first annular abutment and said threads which forms a stop for said seal washer. 7. A fitting according to claim 2, wherein said flexible ring has a U-shaped axial cross section. 8. A fitting according to claim 1, wherein the first end region of said fitting body is provided with exterior threads and an inwardly directed compression surface for cooperating with a compression nut and ferrule appropriately arranged on the pipe. 9. A fitting according to claim 1, wherein the first end region of said fitting body is adapted to be welded to the pipe. 10. A fitting according to claim 1, wherein said fitting body is comprised of first and second separate components connected together by a fluid tight joint, said first component containing said first end region and said second component containing said second end region. 11. A fitting according to claim 10, wherein said first component is provided with exterior threads and an inwardly directed compression surface for cooperating with a compression nut and ferrule appropriately arranged on the pipe. 12. A fitting according to cliam 10, wherein said first component is adapted to be welded to the pipe. 13. A fitting according to claim 10, wherein said first and second components are connected together by a welded joint.