Patent Publication Number: US-2010127493-A1

Title: Connecting arrangement for a pipe union

Description:
The invention relates to a connecting arrangement for connecting a cylindrical pipe or pipe section to a connecting body, whereby the connecting body has a first conical bore that proceeds from a face surface, a first cylindrical bore that follows the conical bore, to accommodate the pipe, and a second cylindrical bore that follows the first cylindrical bore and is reduced in diameter, with a union nut that has a bore for the pipe or pipe section, with a thread with which the union nut can be screwed onto a counter-thread of the connecting body, and with a conical bore that narrows opposite to the conical bore of the connecting body, with a region of the pipe provided adjacent to the end of the pipe or pipe section that bulges outward all around, which bulged-out region has a bracing surface that interacts with the conical bore of the union nut and is configured as a mirror image of this conical bore. 
     Pipe unions are supposed to become possible with such connecting arrangements. In this connection, a pipeline, particularly a metallic one, is supposed to be connected to a connecting piece that has an accommodation opening for the pipeline. The pipeline has a region that bulges outward all around, adjacent to its end. It is therefore formed here, generally swaged. 
     A union nut that can be screwed together with the connecting piece can be rotated when this formed pipeline end is connected, and thus exerts an axial movement onto this bulged-out region that is situated between the union nut and the connecting piece. A conical bore situated in the union nut, which is configured as a mirror image of the bracing surface of the bulged-out region, then ensures that the bulged-out region is drawn onto the connecting piece and is held tightly there in screwed-on form. 
     Such a concept is known, for example, from DE 195 11 063 C2. In this connection, the bulged-out region of the pipe contains passages, on the one hand, that contain mirror-image bracing surface of the cone angle of the union nut, as well as other cone-shaped regions that support themselves on the conical bore of the connecting piece, in order to allow a secure hold there, as well. In individual embodiments, it is furthermore proposed to dispose seals in various forms in the remaining free spaces between the outer wall of the pipe, the inner wall of the union nut, and the upper face surface of the connecting piece; these seals lie around the pipe in ring shape or disk shape. 
     Another pipe union with a ring bead on a pipeline, which bead surrounds the connecting end, is known from DE 101 24 874 A1. There, a ring-shaped circumferential seal is introduced into a region in the conical bore in the connecting piece, whereby the ring bead is also introduced into this conical bore, so that there, the most reliable sealing possible can take place. Furthermore, a circumferential support ring is laid in between union nut and the ring bead, in order to prevent the pipe from being turned during assembly, and to be able to use a standardized union nut at different inclines. 
     It is problematic that either great interventions in the inside diameter of the pipe end have to be undertaken, or that inaccuracies in the assembly and/or disadvantageous influences of force can occur when the individual elements are joined together. 
     In contrast with this, it is the task of the invention to propose a connecting arrangement for connecting cylindrical pipes of pipe sections to a connecting body, which allows a more advantageous flow of force during the assembly process. 
     This task is accomplished, in the case of a connecting arrangement of the stated type, according to the invention, in that an intermediate ring is provided, that the intermediate ring has a bore for the pipe or pipe section, that the intermediate ring is disposed between the region of the pipe or pipe section that bulges outward all around and the connecting body, and that the intermediate ring supports itself on the face surface of the connecting body. 
     The task is surprisingly accomplished in this way. By means of providing an intermediate ring having precisely the defined properties, it becomes possible to separate the individual functions that, in the final analysis, have to be guaranteed by the connecting arrangement, from one another. This particularly relates to the sealing function, which can be completely separated from the actual connecting process, in which separate properties are assigned to the components. 
     In contrast to DE 101 24 874 A1, it is also no longer necessary to seal two conical surfaces relative to one another, since the entire bulged-out region no longer has to project into the conical bore of the connecting piece, but rather, supports itself on the outside, on the intermediate ring disposed in between. 
     The intermediate ring not only allows separation of the different functions of the connecting arrangement, but also allows contact limitation of the pipe. In the state of the art, it was not precisely defined up to what point the lower end of the pipe can penetrate when it is connected to the connecting piece. In some cases, the inner face surface of the connecting piece was simultaneously the contact limitation, and this could lead to over-assembly. 
     According to the invention, however, the intermediate ring leads to the result that a play between this face surface and the lower end of the pipe, which play is intentionally kept small, can be aimed at, and this can also be utilized for balancing out production tolerances in the production of the bulged-out region. 
     Furthermore, it is possible, in a preferred embodiment, to integrate a soft seal into the connecting arrangement, and to allow this soft seal to be carried by the intermediate ring. In this connection, this soft seal can also be spatially separated from the bulged-out region. It is furthermore particularly advantageous if the connecting arrangement is configured in such a manner that the region that bulges outward all around has a rest surface on its side that faces away from the conical bore of the union nut, that the intermediate ring has a support surface for this rest surface, and that the rest surface and the support surface are configured as mirror images. 
     In this connection, it is particularly interesting to configure the rest surface in such a manner that its incline amounts to between 10° and 15°, particularly 11° relative to the horizontal, whereby this incline is directed upward, in the direction toward the pipe axis, in other words an undercut behind the bulged-out region of the pipe is formed. 
     In this manner, it becomes possible to achieve an improved distribution and direction of effect of the forces that occur. 
     Ideally, the force that acts on the pipe would stand vertically on the bracing surface of the union nut. In the case of conventional unions, however, the force usually stands at a 45° angle on this surface. According to the invention, however, a reduction of this angle to 30 to 35° is possible, thereby reducing the radial component of the force. 
     The preferred angle on the order of 10 to 15° is preferred because even greater angles can be implemented only with significant mechanical effort, and the angle now preferred represents a particularly skillful compromise between the angles that are technically aimed at and those that are feasible. 
     The angles allow a relatively homogeneous flow of force. 
     Over-assembly of the system is reliably prevented by the preferred arrangement of the intermediate ring. Furthermore, the operator is given a clear signal once the pipe to be connected has set itself down onto the connecting piece by way of the intermediate ring, and thus an optimal connection has been achieved. 
     The change in the inside contour of the pipe in the bulged-out region is minimal. As a result, the flow is hindered as little as possible. As a result, noise development is countered with particular prospects of success. 
     The force required for forming the pipe is also reduced, since the configuration of the bulged-out region as described can be achieved with relatively little force. 
    
    
     
       An exemplary embodiment of the invention will be explained in greater detail in the following, using the drawing. This shows: 
         FIG. 1  a section through an embodiment of a connecting arrangement according to the invention; 
         FIG. 2  a representation of an element from  FIG. 1  for a more detailed explanation; and 
         FIG. 3  an enlarged representation of a detail from  FIG. 2 . 
     
    
    
     A pipe union of a pipe  10  with a connecting body  20  is explained in greater detail in  FIG. 1 . The pipe  10  is cylindrical; in  FIG. 1 , a lower end of the pipe  10 , which can be significantly longer and could also be part of a pipeline arrangement, is shown as an example. 
     This pipe  10  is inserted into a connecting body  20 . For this purpose, the connecting body  20  possesses a first cylindrical bore  21 , which is precisely dimensioned so that the pipe  10  can be inserted there. A second bore  22  is provided with a smaller diameter. This second bore  22  continues the first bore in the direction of the interior of the connecting body  20 . A medium situated in the interior of the pipe  10  can thus get into the second bore  22  and be conveyed further there. 
     Furthermore, a face surface  25  is provided, which separates the first bore  21  and the second bore  22  from one another. 
     Another face surface  24  is provided as the outer surface of the connecting body  20 ; in this connection, the first, outer cylindrical bore  21  makes a transition into a conical bore  23  that opens in the direction of the face surface  24 . 
     On the outside, the connecting body  20  also has a thread  28 , which is equipped for forming a screw connection with a counter-thread  38  that will still be described further in the following. 
     Specifically, a union nut  30  having this counter-thread  38  can be screwed onto the thread  28  of the connecting body  20 . The union nut  30  possesses a bore  31  through which the pipe  10  can be guided. Between the bore  31  and the thread  38 , another section is provided, in which the bore through the union nut  30  widens in the direction toward the connecting body  20 , as a conical bore  33 . 
     In this region, the pipe  10  possesses a region  11  that bulges outward all around, adjacent to its end. This bulged-out region  11  is achieved by swaging the pipe. The inside diameter of the pipe  10  can be expanded slightly in the region  11 , as can be seen in  FIG. 1 . The region  11  that bulges outward all around is configured uniformly on the entire circumference of the pipe  10 . 
     The bulged-out region possesses a bracing surface  12  that matches the conical bore  33  of the union nut  30  and is configured as a mirror image to it on its side facing away from the connecting body  20 . This bracing surface  12  is therefore also configured conically and widens downward in the direction of the connecting body  20 . 
     Seen from the lower side of the pipe  10 , the region  11  that bulges outward all around is at first equipped with a surface that is horizontal, in a first approximation, namely a rest surface  13 , which will be described in greater detail further below. This rest surface  13  then makes a transition into a conical support surface  14 . 
     An intermediate ring  50  is disposed between the region  11  of the pipe  10  or pipe section that bulges outward all around and the connecting body  20 . This intermediate ring  50  also possesses a bore  51  for the pipe  10  and surrounds this pipe  10 . The intermediate ring  50  can also be referred to as an adapter element or as a holding ring. 
     This intermediate ring  50  possesses a circumferential support surface  52  with which it lies on the face surface  24  of the connecting body  20 . 
     Furthermore, the intermediate ring  50  possesses a conical bore  53  adjacent to the bore  51 . The bulged-out region  11  sits on the intermediate ring  50  with its rest surface  13  in this conical bore  53 . 
     The conical bore  53  in turn borders on and makes a transition into another conical bore  53  of the intermediate ring  50 , which lies opposite the conical surface  14  of the bulged-out region, as a mirror image. 
     The intermediate ring  50  furthermore carries a soft sealing element  60 . This soft sealing element  60  is situated between the outer wall of the pipe  10 , the conical bore  23  of the connecting body  20 , and a corresponding carrying device of the intermediate ring  50 . Since the intermediate ring  50  also borders on the outer wall of the pipe  10 , the soft sealing element  60 , which also runs around the pipe  10 , is permanently mechanically separated from the region  11  that bulges outward all around. 
       FIG. 2  shows the lower section of the pipe  10 , which is relevant here, separately once again. In this connection, the inner bore of the pipe  10  is assumed to have a constant diameter, in contrast to  FIG. 1 . 
     The region  11 , which bulges outward all around, can be clearly seen. This region  11  is delimited in the upward direction by a conical bracing surface  12 . The surface of this conical bracing surface  12  encloses an angle of approximately 45° with the vertical, axis-parallel wall of the pipe  10 , as can be seen in  FIG. 2 . 
     The region  11  of the pipe  10  that bulges outward all around is shown once again in  FIG. 3 , enlarged, as Detail B. 
     Aside from the bracing surface  12 , here one can also see that the underside of the region  11  that bulges outward all around is taken up by a rest surface  13 . This rest surface  13  runs approximately, but preferably not precisely perpendicular to the axis-parallel wall of the pipe  10 . Upon close inspection, it encloses an angle of about 10 to 15°, in the preferred embodiment shown of 11°, with this perpendicular. In this connection, this rest surface  13  again is configured to be conical, overall, whereby the conicity is oriented in the same orientation as the conical bracing surface  12 , but, as has been mentioned, possesses a different cone angle. 
     In this connection, attention is paid, in all cases, to ensure that the cone surfaces make a rounded transition into the adjacent surfaces, and that no pointed edges are provided. 
     A conical surface  14 , which also runs all around, is provided between the two cone-shaped surfaces  12  and  13  that possess the same orientation. 
     Aside from the angle A of 11°, which the rest surface  13  encloses with the horizontal, an angle B of 30° is also shown. The angle B reproduces the force progression at which 30° represents a difference component. 
     REFERENCE SYMBOL LIST 
       10  pipe (cylindrical) 
       11  region of the pipe bulging outward all around 
       12  bracing surface 
       13  rest surface 
       14  conical surface 
       20  connecting body 
       21  bore (first cylindrical bore for the pipe  10 ) 
       22  bore (second, having a smaller diameter) 
       23  conical bore 
       24  face surface, against the intermediate ring 
       25  face surface, against the pipe  10   
       28  thread for screw connection with union nut  30   
       30  union nut 
       31  bore for the pipe  10   
       33  conical bore 
       38  thread for screw connection with connecting body  20   
       50  intermediate ring 
       51  bore for pipe  10   
       52  support surface against connecting body  20   
       53  cone relative to rest surface  13  of region  11   
       54  cone relative to conical surface  14  of region  11   
       60  soft sealing element