Tapping Saddle

Abstract: A tapping saddle comprising a housing (1) for being tightened against a pipe (3), said housing (1) having a throughgoing opening for drilling through the pipe wall, and a sealing ring (5) provided in the housing (1) in order to be pressed against the pipe wall around a hole to be drilled therethrough. In order to secure sealing also if the housing is not completely tightened against the pipe wall, and in order to compensate for a possible deformation of the pipe wall due to the force exerted by the sealing ring (5), the sealing ring (5) is situated against a compensator sleeve (4) being shiftably provided in the housing (1) and influenced by means (6) for exerting a springy force in order to be biased towards the pipe wall.

Description: The present invention relates to a tapping saddle, i.e. a saddle that can be coupled to the outside of a pipe for drilling through the pipe wall, in order to constitute a coupling point for a second pipe forming a branch from the first pipe. Such saddles comprise a housing having a throughgoing opening through which drilling can be performed. On a concave end of the housing, being conformed to the curvature of the pipe and adapted to face the pipe, a sealing ring is normally mounted, for instance an O-ring, adapted to be pressed against the pipe wall around the hole to be drilled. The O-ring has to be bent into a curvature corresponding to the curvature of the concave end of the housing. The housing can be tightened against the pipe, which may be carried out by use of different members, such as a bridle, by screwing the housing and the bridle together. When a bridle is being used, the housing and the bridle are adapted to a certain pipe dimension, in that the bridle has such a length that tightening of the housing can take place, whereby the O-ring is compressed against the pipe and causes sealing. It must, in other words, be ensured that the housing is correctly tightened against the pipe and that the O-ring is actually compressed. If the bridle is too long for the pipe in question, or if other means are used which do not bias the housing correctly against the pipe, the tightening of the housing will be incomplete. Even when the housing is correctly tightened a leakage may occur due to deformation of the pipe wall by the force exerted by the O-ring. A tapping saddle is described in FR 2 772 874. The sealing ring is compressed by screwing a sleeve onto the saddle. The operator has to judge whether the sleeve has been screwed adequately onto the saddle for complete sealing to occur. This involves a degree of uncertainty as the operator cannot see the contact made by the sealing ring on the pipe to be tapped. The above problems are avoided by the present invention. The tapping saddle according to the present invention is defined by claim 1. Embodiments of the tapping saddle are defined by the dependent claims. The compensator sleeve constituting a carrier for the sealing ring can be shifted inside the housing, and is subjected to a biasing or springy force in the direction towards the pipe wall. Thereby is ensured that the sealing ring is pressed against the pipe wall by a suitable force, also if the housing is not completely tightened against the pipe. Moreover, the springy force compensates for a possible deformation of the pipe wall. The housing can be tightened against the pipe by use of various members, and a bridle is merely mentioned as an example. The housing may for instance be lashed against the pipe. Another example is the use of one or more clamping rings or bands tightened around the housing and the pipe. Still another example is the use of a plate or rod instead of a bridle. The invention is not limited with respect to such tightening means. The invention will in the following be explained more detailed, with reference to the accompanying drawing, showing an example of an embodiment of a tapping saddle according to the invention. Fig. 1 shows in an axial projection a pipe on which has been mounted a tapping saddle according to the invention. Fig. 2 shows a section through the pipe and the saddle, along the line I-I in Fig. 1. Fig. 3 shows the different parts of the saddle and the pipe in an exploded view. In the embodiment shown the tapping saddle according to the invention comprises a housing 1 and a bridle 2. The housing 1 can be tightened against a pipe 3 by means of screws 9 and nuts 10, whereby the housing 1 and the bridle 2 together surround the pipe 3, as it appears from Fig. 1. For instance four screws 9 and nuts 10 can be used, without this being mentioned as a limitation. As shown in Fig. 2 the housing 1 contains a compensator sleeve 4, and a sealing ring 5 is situated against the inner end of the sleeve 4, possibly in a concavely curved ring groove at that end. By tightening of the housing 1 against the pipe 3 the sealing ring 5 will be pressed against the outside of the pipe 3, in that the sleeve 4 is pressed towards the outside of the pipe 3 by a spring 6. Fig. 2 also shows a second sealing ring 7 in a ring groove 13 on the exterior of the sleeve 4 and a third sealing ring 8 in a ring groove 14, also on the exterior of the sleeve 4, at the axially outermost end thereof. These sealing rings 7 and 8 cause sealing between the sleeve 4 and the housing 1. In the embodiment shown the housing 1 comprises an interior, thin sleeve-shaped wall 11 against which the sealing ring 8 is situated and which delimits a space 12 for the spring 6. Fig. 3 shows screws 9 and nuts 10, but it will be appreciated that the housing 4 or the bridle 2 may have threaded holes into which the screws 9 can be screwed, whereby nuts can be omitted. It will also be appreciated that screws and nuts used for tightening merely constitute examples, as any mechanism suited for tightening can be used. As an example is mentioned a locking clamp. Fig. 3 shows a single helical spring 6, but it will be appreciated that two or more springs can also be used. Fig. 3 also shows a curved O-ring 5 for sealing against the pipe 3. However, a normal O-ring will adapt itself to the curvature of the pipe and needs not initially be curved. As mentioned the spring biased compensator sleeve 4 will ensure sealing against the pipe 3 even when the housing 1 has not been correctly tightened against the pipe 3, and deformation of the pipe wall due to the force exerted by the sealing ring 5 will be compensated for by shifting of the compensator sleeve 4. All of the sealing rings can be O-rings or other types of sealing rings.

Claims: A tapping saddle comprising a housing (1) for being tightened against a pipe (3), said housing (1) having a throughgoing opening for drilling through the pipe wall, a sealing ring (5) provided in the housing (1) in order to be pressed against the pipe wall around a hole to be drilled therethrough, wherein the sealing ring (5) is situated against an inner end of a compensator sleeve (4) shiftably provided in the housing (1) characterised in that the inner end of the compensator sleeve is concavely curved and in that a helical spring acts against the compensator sleeve, the helical spring being mounted in a space in the housing such that when the housing is tightened against a pipe the spring urges the sleeve towards the pipe and the sleeve presses the sealing ring against the pipe wall. A tapping saddle as claimed in claim 1, wherein the compensator sleeve (4) has a groove for the sealing ring (5) in its innermost end. A tapping saddle as claimed in claim 1 or 2, wherein a second and a third sealing ring (7, 8) for sealing between the compensator sleeve (4) and the housing (1) are situated in a respective ring groove (13, 14) on the exterior of the compensator sleeve (4). A tapping saddle as claimed in claim 1 or 2, wherein the housing (1) contains an interior sleeve-shaped wall (11) forming a partition between the helical spring (6) and a portion of the compensator sleeve (4), and that the third sealing ring (8) is situated against this wall (11).

Inventors: MONSEN ALF GREVE, SLATTSVEEN TORE, MONSEN, ALF GREVE, SLATTSVEEN, TORE
Applicants: RAUFOSS WATER & GAS AS
Application year: 2001
Main classification: F16L41
IPC codes: F16L41