GB2525970A

GB2525970A - Improvements to wing seals

Info

Publication number: GB2525970A
Application number: GB1504028.0A
Authority: GB
Inventors: Mark Almond; Kashif Mohammad; Abhishek Asthana
Original assignee: B S STAINLESS Ltd
Current assignee: B S STAINLESS Ltd
Priority date: 2014-03-12
Filing date: 2015-03-10
Publication date: 2015-11-11
Anticipated expiration: 2035-03-10
Also published as: GB2525970B; GB201404382D0; GB201504028D0

Abstract

A wing seal 20 for securing banding is fabricated from a one-piece pressing 21 by bending the pressing 21 so that opposite edges 26 of the pressing 21 abut one another along a cut 34 running the full length of the wing seal 20. This defines a closed channel 31 at one end and an open channel at an opposite end, the open channel having two opposing side walls that respectively define two wings 32. Opposite edges 23 of the side walls 33 of the wing seal 20 between the closed channel 31 and the wings 32 arc inwardly of the side walls 33. In use, this means that the load borne by the wing seal 20 is distributed over the length of the arcs 23 and the abutting edges 34 of the wing seal 20 are covered and thereby fixed in position. Preferably, the closed channel 31 comprises a face embossed with a bowtie pattern 27. Such a wing seal 20 can be made from a stainless steel pressing 21 that is only 0.70 mm thick without loss of strength but with consequent cost savings. Banding 35 in combination with one or more wing seals 20 is also provided.

Description

IMPROVEMENTS TO WING SEALS

The present invention relates to wing seals for tensioning and securing the banding used to retain cladding or insulation materials around pipework. They are used, in particular, in the oil and gas industries.

A conventional wing seal 1 is shown in Fig. 1 and comprises a one-piece buckle that is pressed from o.8o mm stainless steel sheeting and fabricated to form the wing seal as depicted in the drawing. The pressing is as shown in Fig. 2 and its shape defines three conjoined rectangular portions 2, 3 and 4 as shown by the longer dashed lines. The first rectangular portion 2 is larger than the others in both length and width. The second rectangular portion 3 is smaller than the others in both length and width and effectively forms a neck connecting the first and third portions 2 and 4. The third rectangular portion 4 while larger than the second portion 3 is still smaller than the first portion 2 in both length and width. When the wing seal is fabricated, opposite sides of the pressing are bent upwards at 90° along the dashed lines 5 so that the shorter edges of all three rectangular portions are upright. The ends of the first portion 2 are then bent through 90° again along the dashed lines 6 so that their edges 7 abut one another to form a closed channel 8 at one side of the seal and an open channel 9 at the other side of the seal. The dashed lines 5 are located slightly beyond the shorter edges 0 of the second portion 3 by a distance commensurate with the thickness of the pressing so that only the larger portion 2 forms the channel 9. This leaves the ends of the third portion 4 standing upright beyond the shorter edges 10 of the second portion 3 to form the wings ii of the wing seal 1. In use, banding is threaded through the open channel 9 and the closed channel 8 and then wrapped over the abutting edges 7 using a tensioning tool. The wings 11 are then pressed down over the banding to hold it in position.

Conventionally, in the oil and gas industries the wing seals and the banding they secure are made of stainless steel. This means that they are expensive.

It is an object of the present invention primarily to provide a wing seal that uses less material in its production while retaining and possibly increasing the strength and performance of the wing seal when in use.

According to a first aspect of the present invention there is provided a wing seal fabricated from a one-piece pressing by bending the pressing so that opposite edges of the pressing abut one another along a cut running the full length of the wing seal to define a closed channel at one end and open channel at an opposite end, the open channel having two opposing side walls that respectively define two upstanding wings, opposite edges of the side walls of the wing seal between the closed channel and the wings arcing inwardly of the side walls whereby, in use, the load borne by the wing seal is distributed over the length of the arcs and the abutting edges of the wing seal are covered and thereby fixed in position.

The invention enables the wing seal to be fabricated from stainless steel sheeting that is a thinner gauge than a conventional wing seal of commensurate size and strength. For example, most conventional wing seals are manufactured from stainless steel sheeting that is o.8o mm thick whereas the present invention enables a wing seal to be made from stainless steel sheeting that is 0.70 mm thick. This leads to a significant reduction in the quantity of material used with consequent cost savings.

According to a second aspect of the present invention there is provided banding for use in the retention of cladding or insulation materials around pipework in combination with one or more wing seals in accordance with the first aspect of the present invention.

Other preferred but non-essential features of the various aspects of the present invention are described in the dependent claims appended hereto.

The present invention will now be described by way of example with reference to the accompanying drawings, in which:-Fig. 1 is a perspective view of a conventional wing seal as described above; Fig. 2 is a plan view of a pressing for use in the fabrication of the conventional wing seal shown in Fig. 1; Fig. 3 is a perspective view of a wing seal in accordance with the present invention; Fig. 4 is an end view of the wing seal in the direction of the arrow in Fig. 3; Fig. 5 is a side view of the wing seal shown in Figs. 3 and 4; Fig. 6 is a plan view of a pressing for use in the fabrication of the wing seal shown in Figs. 3 to 5; and Fig. 7 is a side view of a wing seal attached to one end of a length of banding ready for use.

A wing seal 20 in accordance with the present invention and as shown in Figs. 3 to 5 is fabricated from a one-piece pressing 21 as shown in Fig. 6.

The pressing 21 comprises a rectangular pressing out of which is cut a T-shape formed by an elongate slot 22 with rounded ends 23, which preferably form semicircular arcs, and a channel 24 which joins a central portion of the slot 22 with the central portion of one longer side 25 of the pressing. The slot 22 is located centrally of the pressing 21 with respect to its longer sides but is offset to one side of the pressing 21 with respect to its shorter sides 26. Adjacent the slot 22, the central part of the other side of the pressing 21 relative to its shorter sides 26 is embossed with a predetermined pattern 27 that is preferably a bowtie pattern, as shown in the drawings. The pattern 27 is raised in relief from the underlying face of the pressing 21.

The wing seal 20 is formed by bending the two ends of the pressing 21 adjacent its shorter sides 26 along first dashed lines 28 through 9Q0* The lines 28 are located on opposite sides of the embossed pattern 27 but inwardly of the rounded ends 23 of the slot 22. The end portions 29 of the folded ends are then bent again through 900 along the dashed lines 30 so that the edges of the shorter sides 26 abut one another along their full length, which is equivalent to the full length of the wing seal 20. The dashed lines are located respectively beyond the rounded ends 23 of the slot 22. This leaves the wing seal 20, as shown in Fig. 3, defining a closed channel 31 with a substantially rectangular cross-sectional profile at one end covered by the portion of the pressing defining the embossed pattern 27 and upstanding is wings 32 at its opposite end. The rounded ends 23 of the slot 22 are therefore located in opposite side walls 33 of the wing seal 20 between the wings 32 and the closed channel 31. The abutting shorter sides 26 of the pressing form a cut 34 that runs the whole length of the central part of the wing seal.

The shape of the fabricated wing seal 20 is now similar to that of the conventional wing seal 1 and can be used in a similar manner. In particular, the ends of banding 35 that is used to retain cladding or insulation materials around pipework are threaded through the channel 31 and wrapped over the portion of the wing seal defining the embossed pattern 27. The banding is then tightened with a tensioning tool and the wings 32 are pressed down with a hammer or similar tool. The pressed-down wings 32 hold the banding in position. However, the differences in the shape of the pressing 21 and manner of fabrication of the wing seal 20 mean that the wing seal 20 has several advantages over the conventional wing seal 1.

First, the rounded ends 23 of the slot 22 are arced inwardly of the side walls 33 along semicircular arcs that distribute the load borne by the wing seal 20 in use over the full length of the arcs 23. This improves the ability of the wing seal 20 to sustain higher loads and enables it to be made from a thinner gauge of sheeting than a conventional wing seal 1 capable of sustain the same load. Whereas the conventional wing seal 1 shown in Fig. 1 is pressed from stainless steel sheeting that is o.8o mm in thickness, the wing seal 20 is preferably pressed from stainless steel sheeting that is 0.70 mm in thickness. The radius of the arc 23 for such a wing seal 20 that has a closed channel 31 with an interior width Wof 21 mm is 1.5 mm.

Second, the embossed pattern 27 increases the strength of the wing seal 20 as it imparts residual stresses to the wing seal 20 and thereby reduces the development of von Mises stresses in use. It has been found that a boie pattern imparts optimum residual stresses for this purpose. For a pressing that is 0.70 mm in thickness, the pattern 27 is preferably raised in relief by 0.40 mm from the underlying face of the pressing 21.

Third, in the wing seal 20 according to the present invention the cut 34 is located on the back side of the wing seal whereas in the conventional wing seal the equivalent cut is located on the front surface of the closed channel 10. As in use wing seals are fixed in position when the banding is tensioned, in the wing seal 20 in accordance with the invention the pressure exerted by the banding on the back side covers the cut 34 and thereby fixes the end portions 29 and abutting edges of the shorter sides 26 in position. In contrast, in the conventional wing seal 1, the tension on the banding when it is folded over the closed channel 10 tends to force the abutting edges 7 apart.

The overall performance of the wing seal 20 in accordance with the invention is thereby improved.

Fourth, the wings 32 of the wing seal 20 are shorter than those of the comparable conventional wing seal 1 of similar strength. In the illustrated example, the wings 32 project upwards by a height H that is between 6% and 7% shorter than that of the wings ii of the conventional wing seal 1.

Reducing the length of the wings 32 increases the torque required to press the wings 32 down into position over the banding during use but therefore increases the torque required to bend the wings 32 were the wing seal 20 to fail. Hence, a higher force is required to open or bend the wings 32 when the wing seal 20 is in use, which is an advantage. It also means that less material is required to make the wing seal. Conventional wing seals 1 are usually made with a length L of 22 mm and with a closed channel 8 that has an interior width J47 of either 15 mm or 21 mm, although other dimensions are possible. In the latter, the height H is typically around 14 mm whereas in the wing seal 20, the height H is typically around 13.15 mm. This coupled with the difference in the thickness of the pressing results in a wing seal 20 that uses 12% less material for its manufacture with consequential cost savings.

The advantages of the wing seal 20 in accordance with the present invention can be seen in the results of tensile load tests conducted on the three prior art wing seals 1, as shown in Table 1 below, and three wing seals 20 in accordance with the present invention, as shown in Table 2 below.

Table 1

UYS or Proof Prior width Thickness Maximum Tensile Strength at YPE/ Wing Seals Maxinmm Ac (Automatic) Load ___________ (mm) (mm) (N) (MPa) (MPa) 1 19 0.8 1167.79 81.24 57.47 2 19 o.8 1193.2 83.01 69.32 3 19 o.8 1197 84.59 72.23

Table 2

Wing Seals Width Thickness Maximum Tensile stress or Proof in accordance Load at Maximum 1tli the Load Ae (Automatic) invention __________ (mm) (mm) (N) (MPa) (MPa) 1 19 0.7 1411 96.15 70.5 2 19 0.7 1419.12 98.72 90.8 3 19 0.7 1415.12 97.23 88.6 It can be seen by a comparison of the results in the tables that the wing seals 20 in accordance with the present invention can sustain an approximately 20% higher load.

In use, wing seals 20 may be supplied already attached to appropriate lengths of banding 35 as shown in Fig. 7. The length of the banding 35 is determined by the outside diameter of pipework to be clad. One end 36 of the banding 35 is passed through the channel 31 in the wing seal 20 and bent around the end of the channel 31 adjacent the upstanding wings 32 to lie contiguous with the lower side of the wing seal 20 covering the cut 34. The wing seal 20 and banding 35 are therefore ready for use to retain cladding or insulation materials around the pipework.

Claims

CLAIMS1. A wing seal for securing banding and fabricated from a one-piece pressing by bending the pressing so that opposite edges of the pressing abut one another along a cut running the full length of the wing seal to define a closed channel at one end and open channel at an opposite end, the open channel having two opposing side wails that respectively define two upstanding wings, opposite edges of the side walls of the wing seal between the closed channel and the wings arcing inwardly of the side walls whereby, in use, the load borne by the wing seal is distributed over the length of the arcs and the abutting edges of the wing seal are covered by the banding and thereby fixed in position.
2. A wing seal as claimed in Claim 1, wherein the arcs are semicircular arcs.
3. A wing seal as claimed in Claim 1 or Claim 2, wherein the closed channel comprises a face embossed with a pattern.
4. A wing seal as claimed in Claim 3, wherein the pattern is a bowtie pattern.
5. A wing seal as claimed in any of Claims 1 to 4, wherein the pressing is 0.70 mm thick and made of stainless steel.
6. A wing seal as claimed in Claim 5 when dependent on Claim 3 or Claim 4, wherein the pattern is raised in relief by 0.40 mm from the underlying face of the seal.
7. A wing seal substantially as described herein with reference to any of Figs. 3 to 6 of the accompanying drawings.
8. Banding for use in the retention of cladding or insulation materials around pipework in combination with one or more wing seals as claimed in any of Claims 1 to 7.
9. Banding as claimed in Claim 8, wherein a wing seal is attached to one end of a length of banding.
10. Banding in combination with a wing seal substantially as described herein with reference to Fig. 7.