Pipe Connection

Abstract

The invention relates to a pipe connection, particularly a gas-tight pipe screw connection, wherein the parts in the connecting region are connected by means of joining according to DIN 8593 by way of contact-pressing and insert-pressing, comprising an inner pipe part (I) and an outer pipe part (A), or two inner pipe parts (I) having an outer collar (A). In order to improve the usage properties in practice in the field, particularly in order to maintain the tightness of the respective pipe connection with combined loading, according to the invention the connection is established using three regions, wherein the connecting regions of the press fit ( 1 ) and stop ( 2 ) of the pipe parts, or the pipe parts and collar, comprise cooperating press fit surfaces ( 1 I, 1 A), which have a truncated cone shape and which are inclined in the end direction from the inner pipe part toward the pipe axis (x), and at the front comprise stop surfaces ( 2 I, 2 A), which have a truncated cone shape and are directed counter to said press fit surfaces ( 1 I, 1 A), and a transition ( 3 ) is formed by the press fit ( 1 ) and stop ( 2 ) of the connected parts for said parts without contact with a coaxial intermediate space or hollow space (R).

1 . Pipe connection, particularly a gas-tight pipe screw connection, wherein the parts in the connecting region are connected by means of joining according to DIN 8593 by way of contact-pressing and insert-pressing, comprising an inner pipe part (I) and an outer pipe part (A), or two inner pipe parts (I) having an outer collar (A), characterized in that the connection is established using three regions, wherein the connecting regions comprise press fit ( 1 ) and stop ( 2 ) of the pipe parts or press fit surfaces ( 1 I,  1 A) that cooperate with the pipe parts and collar and that have a truncated cone shape and that are inclined in the end direction from the inner pipe part toward the pipe axis (x), and at the front comprise stop surfaces ( 2 I,  2 A), which have a truncated cone shape and are directed counter to said press fit surfaces ( 1 I,  1 A) and a transition ( 3 ) is formed by the press fit ( 1 ) and stop ( 2 ) of the connected parts for said parts without contact with a coaxial intermediate space or hollow space (R). 
     
     
         2 . Pipe connection according to  claim 1 , characterized in that the transition ( 3 ), which is implemented without contact between the pipe parts, is the connecting region press fit and stop that is formed by means of a coaxial recess (RA) from the interior wall surface ( 3 A) in the outer pipe part (A). 
     
     
         3 . Pipe connection according to  claim 1 , characterized in that the recess (RA) in the transition region ( 3 ) features a corner-free profile ( 3 A) in cross section. 
     
     
         4 . Pipe connection according to  claim 1 , characterized in that the inner pipe part (I) is shaped in a rounded manner in the region of the transition ( 3 ) by the distally continued press fit surface ( 1 I) and stop surface ( 2 I). 
     
     
         5 . Pipe connection according to  claim 1 , characterized in that the coaxial recess (RA) is implemented in the outer pipe part (A) in the cross section of the press fit surface ( 1 A) to the recess profile ( 3 A) with a transition radius (Ro) of 0.5 to 1.0 mm (Ro=0.5-1.0) and is shaped up to the stop surface ( 2 A) edge-free. 
     
     
         6 . Pipe connection according to  claim 1 , characterized in that the quotient of the length of the transition ( 3 ) that is implemented without contact to the length of the press fit ( 1 ) yields a value from 0.4 to 1.7, preferably from 0.6 to 1.5. 
     
     
         7 . Pipe connection according to  claim 6 , characterized in that for casing pipes according to API 5CT, which are essentially casings with an outer diameter of larger than 4½ inches, the quotient of the length of the transition ( 3 ) that is implemented without contact with the inner pipe part (I) to the length of the press fit ( 1 ) yields a value from 0.4 to 1.2, preferably from 0.6 to 1.0. 
     
     
         8 . Pipe connection according to  claim 6 , characterized in that for casing pipes according to API 5CT, which are essentially riser or conveying pipes with an outer diameter of larger of 4 3/2 inches and smaller, for example 1.66 inches, the quotient of the length of the transition ( 3 ) that is implemented without contact with the inner pipe part (I) to the length of the press fit ( 1 ) yields a value from 0.9 to 1.7, preferably from 1.1 to 1.5. 
     
     
         9 . Pipe connection according to  claim 1 , characterized in that the outer part (A) features a inclination of the press fit surface ( 1 A) of about 1:10 relative to the diameter and the stop surface ( 2 A) features an angle beta of  13  from 10° to 20°, preferably of about 15° to the axis normal. 
     
     
         10 . Pipe connection according to  claim 1 , characterized in that the pipe material is thermally treated or hardened at least in the connecting region and features an increased material strength. 
     
     
         11 . Pipe connection according to  claim 1 , characterized in that the press fit surfaces ( 1 I,  1 A) and/or the stop surfaces ( 2 I,  2 A) feature a surface roughness of less than Ra=3.2 μm, however more than Ra=0.4 μm, measured as a mean roughness value according to DIN 4777 ISO/DIN4287/1. 
     
     
         12 . Pipe connection according to  claim 1 , characterized in that the joining of the pipe parts is accomplished by means of a screw connection.