GB2466964A

GB2466964A - Insert for a conduit

Info

Publication number: GB2466964A
Application number: GB0900645A
Authority: GB
Inventors: John Stobbart
Original assignee: Vector International Ltd
Current assignee: Freudenberg Oil and Gas Technologies Ltd
Priority date: 2009-01-16
Filing date: 2009-01-16
Publication date: 2010-07-21
Also published as: GB0900645D0

Abstract

Arrangements for the installation of an item such as a thermowell or erosion detector insert in a pipeline for transporting gas and/or oil are described. As shown a thermowell comprises an off the shelf a single size forged tee piece 2 and an insert 10 tailored to the length of a thermocouple to be accommodated. In a second aspect (Figure 8 not shown) a forged tee piece is externally tapered at an offset angle such that extra material is provided around the side branch of the tee where extra stresses are present in use. 'This enables a shorter tee to be produced at reduced cost. In a further aspect not shown a similar effect is achieved by providing a forged tee piece having an offset bore such that its wall thickness is greater adjacent its side branch and is less diametrically opposing the side branch.

Description

Insert for a Conduit The present invention relates to an item for installation in a pipe line for transporting, for example, gas and/or oil. In particular, the present invention relates to a tee piece having an aperture for enabling access into the conduit, and an arrangement for plugging the aperture, whereby selective access is enabled to the aperture.

In oil and/or gas pipe lines in particular, it is often necessary to access the inside of the conduit for a variety of reasons. These may be to determine the temperature of the material flowing through the conduit, measure the amount of impurity in the medium or in order to inject certain components into the medium flow. For these purposes it is known to provide an aperture in the conduit having a neck portion and provide an insert having a channel substantially therethrough, wherein the insert is fixed onto the neck in order that thermocouples may be located into the aperture. The insert may have an aperture at both ends enabling injection of a substance into the conduit, or may be sealed and act as an erosion detector. The arrangement is provided such that there is little risk of leakage of gas or oil. Examples of inhibitors that may be injected into the conduit through an insert may be corrosion, scale and waxing inhibitors.

Figures la and b show a prior art tee piece 2 having a bore 4 therethrough which is provided in an elongate conduit and welded at each end to a conduit. Figure la shows a cross sectional view of a small tee piece 2 arranged to receive a short insert and Figure lb shows a longer tee piece 2 which is arranged to receive a larger insert for example. The tee piece 2 is welded at each end 6 to a conduit (not shown). The tee piece 2 has a neck 8 extending from a longitudinal wall of the tee piece 2. The neck 8 has an aperture therein arranged to receive for example a thermowell or erosion detector insert 10. The insert 10 is arranged to seat in the aperture provided in the tee piece 2 wherein a seal ring 12 is provided to seal between the neck 8 and the insert 10. Means may be provided (not shown) such as a releasable clamp to secure the insert 10 against the seal ring 12 thus providing a seal between the inside and outside of the conduit. The insert 10 comprises a head portion 14 and an elongate projecting portion 16 wherein the elongate projecting portion 16 extends from the head 14 and through the wall of the tee piece 2 and into the bore 4. The insert 10 has a channel 18 which extends from an opening 20 in the head portion and extends adjacent the tip of the projecting portion 16. In the event that additives are to be injected into the conduit then one or more apertures may be provided adjacent the tip of the projecting portion 16. The opening 20 may be configured to receive a thermocouple for example.

Disadvantages are associated with the arrangements as indicated in Figures la and lb in that the length for example of the thermocouple dictates the length of the insert 10 and accordingly the length of the neck 8. The first aspect of the present invention provides an improved arrangement.

According to a first aspect of the present invention there is an insert for insertion through an opening in a longitudinal wall of a conduit, the insert comprising: -a head portion arranged to be secured to the conduit; -a first projecting portion extending from the head portion; and -a second projecting portion extending from the head portion in a direction opposing that of the first projecting portion.

The insert preferably defines a channel through at least a portion of each of the head portion, the first projecting portion and the second projecting portion. This channel is beneficially arranged to receive a thermocouple for example, or can be used to inject additives into the conduit.

There are significant advantages associated with an arrangement according to a first aspect of the present invention. These will become apparent from the specific description, however, the present invention enables the manufacturing of a standard tee piece such that these products can be so-called off the shelf components. Inserts 10 may be manufactured for the requirements of a specific system in order to receive the selected thermocouple for example.

The insert is beneficially configured to be releasably connectable to the conduit. In an alternative embodiment, the insert is configured to be fixedly secured to the conduit.

The first projecting portion beneficially has an opening to enable access to the channel.

The opening is beneficially configured to receive a thermocouple. In one embodiment, the first projecting portion may be releasably secured to the head portion. In such an embodiment the head portion and second projecting portion may be manufactured of a single piece of standard dimensions and the first projecting portion may be manufactured in a variety of lengths in order to accommodate various thermocouple (for example) lengths. The first projecting portion may be connected to the head portion via a variety of means such as, for example, mating threads or alternatively via the use of a seal and clamping arrangement.

The cross sectional area of the first projecting portion is preferably less than the cross sectional area of the head portion. The first projecting portion can be of reduced diameter such that material costs are reduced.

The head portion preferably comprises a sealing surface configured to seal against a seal ring.

The second projecting portion is beneficially elongated and even more beneficially is tapered away from the head portion. The channel beneficially extends adjacent but not through the tip of the first projecting portion which is generally used in order to receive a thermocouple or be used as an erosion detector. Alternatively, the channel may extend through the second projecting portion.

The insert may further comprise a tee piece having a longitudinal wall having an opening therein, wherein the opening is configured such that the second projecting portion passes therethrough and the head portion is retained about the opening. A neck preferably extends from a longitudinal wall of the tee piece, the neck having a shoulder preferably defining the opening. The shoulder is preferably configured to receive a seal ring. The head portion may be fixedly secured to the shoulder portion. The neck may be formed integrally with the tee piece and may be manufactured by a forging process.

Alternatively, the neck may be fixedly secured to the tee piece about the opening and in such a configuration a conduit may be provided having an aperture therein and the neck for example welded about the opening.

The arrangement may further comprise a seal ring arranged to seat between the tee piece and the head portion. A clamping arrangement may also be provided to secure the head portion to the tee piece.

The second projecting portion of the arrangement beneficially extends into the conduit when the insert is assembled with the tee piece.

According to a second aspect of the present invention there is a tee piece comprising a conduit portion defining a bore therethrough and a side branch extending from the conduit portion, wherein the conduit portion is externally tapered in a direction towards each end of the conduit, wherein the angle of the taper decreases away from the side branch around the periphery of the conduit portion.

The advantage associated with the second aspect of the present invention is that increased material is provided about the side branch, thereby increasing the strength. The effective thickness of the wall of the conduit around the side branch is of increased thickness as the distance between the bore and the wall of the conduit is increased due to the increased taper angle relative to the longitudinal length of the bore. The thickness of the conduit reduces away from the side branch in a transverse direction. This ensures that extra material is provided about the side branch whereas the opposing side of the conduit is of thinner material where no extra stresses are present.

The angle of the taper preferably progressively decreases to a point diametrically opposing the side branch. In an exemplary embodiment the angle of the taper preferably covers a range of less than 100. Even more preferably, the angle of taper changes from to 2° approximately.

The side branch preferably has a channel defined therethrough. The channel is arranged to receive, for example, an insert which may in turn receive a thermocouple, for example.

A second aspect of the present invention also extends to a method of manufacturing a tee piece comprising the steps of forging the tee piece and subsequently machining a bore to provide a uniform bore. l0

According to a third aspect of the present invention there is a tee piece comprising a conduit portion defining a bore therethrough and a side branch extending from the conduit portion wherein the axis of the bore is offset relative to the axis of the conduit portion, such that the wall thickness of the conduit portion is less diametrically opposing the side branch than the wall thickness of the conduit portion adjacent the side branch.

The bore may therefore be offset relative to the tee piece and as such the wall thickness is greater adjacent the side branch therefore increasing the strength and is of reduced thickness away from the side branch where the stresses in use are less. The axis of the base is preferably offset in a plane parallel to the axis of the conduit.

The wall thickness of the tee piece preferably decreases progressively to a point diametrically opposing the side branch.

The conduit is preferably externally tapered towards each end of the conduit.

Again, beneficially the side branch comprises a channel extending therethrough.

A third aspect of the present invention also extends to a method of manufacturing a tee piece comprising the steps of forging the tee piece and subsequently machining a uniform bore therethrough.

Aspects of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figures la and b are schematic cross sectional representation of prior art arrangements of tee pieces and inserts.

Figure 2 is a schematic cross sectional representation of an insert as found in the prior art.

Figure 3 is a schematic cross sectional representation of a tee piece and insert according to an exemplary embodiment of the present invention.

Figure 4 is a schematic cross sectional representation of an insert according to an exemplary embodiment of the present invention.

Figure 5 is a schematic cross sectional representation of a further exemplary embodiment of an aspect of the present invention.

Figures 6a and b are a schematic cross sectional representations of a further exemplary embodiment of a component of an aspect of the present invention. Figures 6c and d are schematic perspective views of the exemplary embodiment of Figure 6. Figure 6e is a schematic bottom view of the exemplary embodiment of Figure 6.

Figure 7 is a schematic cross section of a tee piece at an intermediate stage of processing

according to the prior art.

Figure 8 is a schematic representation of a cross section of a tee piece during processing of an exemplary embodiment of a second aspect of the present invention.

Figure 9 is a schematic representation of an end view and a side view of a tee piece and insert according to an exemplary embodiment of the present invention.

Referring to Figures 3 and 4 a tee piece 2 is provided having relatively reduced longitudinal lengths wherein a significant advantage of the present invention is that a single size of tee piece 2 may be provided having a common longitudinal length and common length of neck 8 extending in the transversely relative to the conduit. The neck has an aperture therein and defines a shoulder 22 onto which seats the seal ring 12. An annular sealing surface 24 is provided which is energised as the insert 10 is compressed onto the seal ring. A further sealing surface 26 is provided between the insert and the upper part of the seal ring which again forms an annular seal when the seal is energised by compressing the insert 10 against the seal ring. A clamping arrangement is provided (not shown) which is arranged to provide compression against shoulders 28. A second projecting portion 16 extends from the head 14 into the tee piece 2 and may be made a standard length irrespective of the length of thermocouple to be received by channel 18 or of the specified injection pathway. An advantage of a reduced length of projecting portion 16 in comparison to the arrangement as represented in Figure lb is that there is a reduced chance of cracking and breaking through vibration of the projecting portion 16 when medium is flowing through the bore 4.

The head 14 is provided from which extends the first projecting portion away from the head 14 in a direction generally opposite to that of the second projecting portion. This first projecting portion is beneficially elongate and may comprise indicia thereon in order that the insert 10 can be cut to the desired length for the specified thermocouple for example. Alternatively, various inserts 10 can be manufactured each having constant dimensions for the head and second projecting portion wherein the first projecting portion can be manufactured to the desired length. The opening 20 in the upper end of the first projecting portion is beneficially configured to receive a thermocouple or alternatively may be configured to receive an erosion detector. Alternatively, a further seal arrangement may be provided at the opening 20 in order that additives may be injected into the conduit through apertures in or adjacent the tip of the second projecting portion avoiding potential leakage. Alternatively, a seal arrangement may be provided to seal the apertures adjacent the tip of the second projecting portion which are selectively opened.

A pressure sensor can then be provided at the opening 20 to monitor leakage.

Referring to Figure 5 there is an alternative embodiment of the present invention wherein the neck 8 may be secured to a conduit 5 in order to enable access to the conduit. In such an embodiment, an aperture is formed within an elongate wall of a conduit 5 of a generally circular form wherein the transverse cut through the wall of the conduit is substantially perpendicular to the longitudinal length of the conduit. The diameter of the opening 40 is substantially equal to diameter of the opening 42 of the channel 44 extending through the neck. The rim 46 defining the opening may be substantially planar such that the portion of the rim seats into the opening 40 or alternatively may be contoured to correspond to the curvature of the conduit 5. There is a tapered surface 48 extending from the rim 46 outwardly which forms a wedge portion when the neck 8 is located for adhesion to the conduit 5. This wedge portion is filled with a welding material in order to secure the neck 8 to the conduit 5. The weld beneficially extends beyond the tapered surface 48. The neck portion may comprise the same or similar configuration to the embodiment as described with respect to Figure 3 or may alternatively comprise any suitable shape and configuration. An insert may also be provided with a seal ring as described with respect to Figures 3 and 4 which may be secured to the neck 8 in a similar manner. It will be appreciated that a single length of neck 8 may be provided and again the length of, for example, the first projecting portion of the insert may be changed depending on the length of the thermocouple provided.

Referring to Figures 6a to 6e, a further alternative embodiment of the present invention as provided wherein again an opening is cut into a conduit, wherein the cut is made tapering from the outer diameter of the conduit 5 to the inner diameter of the conduit 5. As such, the aperture 80 is substantially in the shape of an ellipse tapered inwardly to the bore 4.

Figure 6a is a cross-sectional representation of a neck according to this exemplary embodiment of the present invention and Figure lb is a representation of the neck as indicated in Figure 6a through the section indicated A-A. The conduit 5 has a substantially ellipsical aperture 80 therein having a tapered surface between the outer and inner surface of the conduit. The neck comprises a tapered rim 82 which is arranged to seat into the aperture in the conduit. Weld material then fills the gap provided between shoulder 84 and the rim 82. A single fluid flow path through the channel 44 is ensured.

It will be appreciated that an advantage associated with the embodiments as described in Figures 5 and 6a and 6b is that openings may be provided on a curved portion of a conduit 5 for example.

Figure 7 is a schematic cross-sectional representation of the first stage of forming of a tee piece 2 available in the prior art. Such a tee piece 2 may be provided via an initial forging process. Recesses 50 are formed into a solid piece of metal via pins provided on the forging mould. The forging mould, and in particular the pins, causes flow of metal into an opening provided in the forging mould into which the rim 52 of the conduit portion of the tee piece 2 flows. The neck 8 is also formed during the initial forging. A plug 54 blocks the central bore of the tee piece 2 which must be drilled out during the subsequent finishing processes. It is possible to reduce the width of the plug 54 by increasing the length of the pins provided on the forging mould, however, the length of such pins is limited due to problems with breakages.

Exemplary angles of the internal taper of the bore are shown as approximately 100, and in an exemplary embodiment may be approximately 7°. Such angles are present in order that release of the pins from the forging is achieved. The tee piece 2 also has an outer taper again provided in order that release from the forging mould is achieved. Such an angle may as an example be 5°. During subsequent forming of the finished tee piece, the plug 54 is machined away forming a constant internal bore diameter. A neck 8 is also drilled in order to provide an aperture therethrough and further machining is carried out in order to reduce the outer diameter of the neck whilst providing a head suitable for communication with a clamp arrangement. Such an arrangement cannot be formed during forging due to the difficulties with the flow of the metal. The rim 52 is of sufficient length in order that the necessary weld preparation may be carried out for subsequent welding onto a conduit.

Referring to figure 8 there is an exemplary embodiment of one aspect of the present invention showing the intermediate formation of a forging according to an exemplary embodiment of the present invention. It will be appreciated that the angles as shown are exemplary only, and the present invention is not limited in this regard.

Figure 8 is a schematic cross-sectional representation of an exemplary embodiment of one aspect of the present invention. The tee piece 2 an indicated in figure 8 differs from the prior art in that the neck 8 is of reduced height and the longitudinal length is significantly reduced. The strength of the tee piece 2 is significantly increased over the arrangement as represented in figure 7, as the portion of the neck 8 generally indicated by reference numeral 56 is of increased thickness. This is the point at which the stresses in such a tee piece are high, and increasing the material around this point has an associated effect of increasing the strength. As shown in figure 8, the external taper of the tee piece 2 generally adjacent the neck 8 is of an increased angle relative to the prior art. The angle in an exemplary embodiment may be of the order of 100 relative to the longitudinal length of the tee piece 2. The angle is obtuse relative to the perpendicular to the longitudinal length of the tee piece 2. It will be appreciated that increasing this angle causes the amount of material at 56 to be increased, thus increasing the strength at this point. The angle of the taper gradually reduces away from the neck 8 until at the point of the tee piece 2 generally opposing the neck 8, the angle of taper may be of the order of 2° relative to the longitudinal length of the tee piece 2. The taper reduction is beneficially gradual from about the neck 8 to the outer side of the opposite side to the neck of the tee piece 2. As maybe more clearly seen from figure 9b, a centre point of the neck 8 about the perimeter of the tee piece 2 is provided and the taper decreases outwardly from this point.

As is clear from figure 8, the reduction in longitudinal length of the tee piece 2 results in the requirement for drilling out of the plug 54 to be significantly reduced. Such a plug 54 may be simply pushed out. Again, the internal taper is provided in order that the tee piece 2 may be easily released from the forging mould. As an example an angle of 10° has been shown, however, in one embodiment as such an angle could be of the order of 7° or less.

The compromise with respect to the angle of taper is that a reduced angle produces less waste and requires less drilling whilst an increased angle increases the ability for the forging to be released from the forging mould. Due to the reduced longitudinal length of the rim 52 and increase in thickness at 56, the shoulder 58 can be forged thereby reducing subsequent machining costs. Due to the reduction in angle of taper of the outer surface of the tee piece 2 generally opposing the neck 8, reduction in wasted metal and subsequently machining is achieved. At this portion of the tee piece 2, there is a reduced requirement for increased strength compared to adjacent the neck 8. Accordingly during the initial forging process there are significant advantages associated with the forged product.

Subsequent machining costs are reduced, and the associated volume of wasted material is also reduced. This is particularly important in the wall of the conduit being reduced on the side opposing the neck 8. It is also apparent in that the neck 8 has reduced subsequent machining requirements as there is already present a shoulder 58.

Referring to figures 9a and b, there is a schematic representation of an end view of the tee piece 2 and a side view of the tee piece 2 respectively. In this schematic representation the insert 10 is located sitting about the opening of the neck 8. Figure 9a clearly shows the final machined product whereby the wall thickness of the tee piece 2 adjacent the neck 8 is thicker than the wall thickness portion of the tee piece 2 opposing the neck 8.

The gradually reducing taper is clearly shown.

In an alternative embodiment, a similar effect may be achieved by the provision of an eccentric bore. Once the uniform bore had then been drilled through, an increased amount of metal would be left about the neck 8 and the opposing side would be of reduced thickness. In such an embodiment the outer taper may be constant and the outer edge of the tee piece 2 viewed end-on would not be concentric with the bore. Instead, the axis of the centre of the bore would be moved downwardly relative to the neck 8.

The present invention has been described by way of example only and appreciated by a person skilled in the art that modification and variations may be made to the present invention without departing from the scope of protection afforded by the appended claims.

Claims

claims I. An insert for insertion through an opening in a longitudinal wall of a conduit, the insert comprising: -a head portion arranged to be secured to the conduit; -a first projecting portion arranged to extend from the head portion; and -a second projecting portion extending from the head portion in a direction opposing that of the first projecting portion.
2. The insert according to claim 1 wherein the insert defines a channel through at least a portion of each of the head portion, the first projecting portion and the second projecting portion.
3. An insert according to any preceding claim configured to be releasably connectable to the conduit.
4. An insert according to any of claims 1-2 configured to be fixedly secured to the conduit.
5. An insert according to any preceding claim wherein the first projecting portion has an opening to enable access to the channel.
6. An insert according to any preceding claim wherein the first projecting portion is releasably secured to the head portion.
7. An insert according to any preceding claim wherein the cross sectional area of the first projecting portion is less than the cross sectional area of the head portion.
8. An insert according to any preceding claim wherein the head portion comprises a sealing surface configured to seal against a seal ring.
9. An insert according to any preceding claim wherein the second projecting portion is elongate.
10. An insert according to claim 8 wherein the second projecting portion is tapered away from the head portion.
11. An insert according to any preceding claim wherein the channel extends adjacent but not through the tip of the second projecting portion.
12. An insert according to any of claims 1-10 wherein the channel extends through the second projecting portion.
13. A system comprising an insert according to any preceding claim and further comprising a tee piece having a longitudinal wall having an opening therein, wherein the opening is configured such that the second projecting portion passes therethrough and the head portion is retained about the opening.
14. A system according to claim 13 wherein a neck extends from the longitudinal wall of the conduit, the neck having a shoulder defining the opening.
15. A system according to claim 14 wherein shoulder portion is configured to receive a seal ring.
16. A system according to claims 14 and 15 wherein the head portion is fixedly secured to the shoulder portion.
17. A system according to claim 14 wherein the neck is formed integrally with the tee piece.
18. A system according to claim 14 wherein the neck is fixedly secured to the tee piece about the opening.
19. A system according to claim 13 further comprising a seal ring arranged to seat between the tee piece and the head portion.
20. A system according to claim 13 wherein the second projecting portion of the arrangement extends into the conduit when assembled together.
21. A tee piece comprising a conduit portion defining a bore therethrough and a side branch extending from the conduit portion, wherein the conduit portion is externally tapered in a direction towards each end of the conduit, wherein the angle of the taper decreases away from the side branch around the periphery of the conduit portion.
22. A tee piece according to claim 21 wherein the angle of the taper progressively decreases to a point diametrically opposing the side branch.
23. A tee piece according to any of claims 2 1-22 wherein the angle of the taper covers a range of less than 10°.
24. A tee piece according to claim 23 wherein the angle of the taper changes from 10° to 2°.
25. A tee piece according to any of claims 2 1-24 wherein the side branch has a channel defined therethrough.
26. A method of manufacturing a tee piece according to any of claims 2 1-25, the method comprising forging the tee piece and subsequently machining a bore to provide a uniform bore.
27. A tee piece comprising a conduit portion defining a bore therethrough and a side branch extending from the conduit portion, wherein the axis of the bore is offset relative to the axis of the conduit portion such that the wall thickness of the conduit portion is less diametrically opposing the side branch than the wall thickness of the conduit portion adjacent the side branch.
28. A tee piece according to claim 27 wherein the axis of the bore is offset in a plane parallel to the axis of the conduit.
29. A tee piece according to claim 27 wherein the wall thickness of the conduit portion decreases progressively to the point diametrically opposing the side branch.
30. A tee piece according to any of claims 27-29 wherein the conduit is externally tapered towards each end of the conduit.
31. A tee piece according to any of claims 27-30 wherein the side branch comprises a channel therethrough.
32. A method of manufacturing a tee piece according to any of claims 27-31, the method comprising the steps of forging the tee piece and subsequently machining a uniform bore therethrough.