Field of the Invention

The present invention relates to an end closure device adapted to be used in connection with internal hydrostatic pressure testing of polymer tubes and of the type indi- cated in the preamble of claim 1.

Background of the Invention

When performing internal hydrostatic pressure tests of polymer tubes use is made of special end closures, which are mounted at opposite ends of a sample of the actual polymer tube in order to seal of the sample to be tested. One of the end closures is a so-called blind end closure part provided only with an air escape valve, while the opposite end closures is provided with an inlet valve system adapted to connect the testing tube sample with an external pressure testing equipment station during the internal hydrostatic pressure test. The pressure station is started while said air escape valve is open, when the sample is completely aired out, the test can be started.

Known end closures of the art in question are normally produces from moulded items by milling into the correct configuration and dimensions. Most often such end closures are divided into two or more parts being adapted to mount by assembling around opposite ends of the tube to be tested.

When it comes to very large end closures they are normally made by a moulded item made from an alloy of aluminium and bronze, which means that end closures for very large tubes having a diameter in the range of 2000 - 2500 mm are very heavy and very expensive to produce and indeed very difficult to handle and transport. Object of the Invention

On that background it is the present invention has for its purpose to provide a new and improved end closure device of the art in question by means of which the above mentioned disadvantages by known end closures devices by simple provisions are met and other important advantages may be achieved. Description of the Invention

The end closure device according to the invention is characterised in, that said one or more squeezing parts each being built-up of a number of piled up and interconnected plate elements the configuration of each of which being provided by a cutting opera- tion such as laser cutting or water cutting. By simple provisions the above mentioned disadvantages by known end closures devices are met and other important advantages may be achieved as well.

Appropriately, the end closure device according to the invention may be such pro- vided that said one or more squeezing parts comprise external, radial connection means consisting of plate elements the configuration of which being provided by a cutting operation such as laser or water cutting.

In order to ensure a simple and quick production the end closure device according to the invention may be such provided that said interconnecting of piled up plate elements being provided by spot welding of the respective plate elements to connection rods or the like extending through the pile.

And in order to further support a quick and effective production the end closure de- vice according to the invention may advantageously be such provided that said exterior ring-shaped part of said dome-shaped end cap being connected with one or more squeezing parts by means of external, radial connection means consisting of plate elements the configuration of which being provided by a cutting operation such as laser or water cutting.

It may be appropriate to modify the end closure device according to the invention such that said one or more squeezing parts comprising axially extending connecting members adapted to connect the mainly dome- shaped end cap to the squeezing parts after the latter have been mounted around the opposite ends of the tube to be tested.

And in order to ensure proper skid-proof connection between the respective parts the end closure device according to the invention may be such provided that one or more plate elements forming the piled up plate elements of said one or more squeezing parts at internal edges being provided with inwardly projecting tooth adapted to ensure skid-proof connection between the squeezing parts and the outside wall of the tube sample.

The end closure device according to the invention may be such provided that said one or more squeezing parts being provided into three parts each of which extend through 120° and consist three radial arranged pairs of assembling flanges.

Or the end closure device according to the invention may be such provided that said one or more squeezing parts being provided into four parts each of which extend through 90° and consist four radial arranged pairs of assembling flanges.

Alternatively the end closure device according to the invention may be such provided that said one or more squeezing parts being provided into two parts each of which extend through 180° and consist two radial arranged pairs of assembling flanges.

Preferably the end closure device according to the invention being such provided that each of said piled up and interconnected plate elements and each of said external, radial connection means consist of stainless steel plate.

Description of the Drawing

In the following the invention is explained in more details with reference to the accompanying drawing, in which:

Fig. 1 shows a plane view of an embodiment for an end closure device according to the invention - mounted at an end of a polymer tube sample,

Fig. 2 shows a perspective view of the end closure device shown in Fig. 1 - as seen from an open end of the tube sample,

Fig. 3 shows a perspective view of the end closure device shown in Fig. 1 - as seen from another angle of said open end of the tube sample,

Fig. 4 shows a perspective view of another embodiment for the squeezing parts of an end closure device according to the invention, shows a plane view of the squeezing parts of an end closure device shown in Fig. 4 - as seen from one side thereof, Fig. 6 shows a plane view of the squeezing parts of an end closure device shown in Fig. 4 - as seen from one end thereof,

Fig. 7 shows a perspective view of another embodiment for the squeezing part of a very large end closure device according to the invention,

Fig. 8 shows a perspective view of details of the assembling parts of the squeezing parts shown in Fig. 7,

Fig. 9 shows a perspective view showing other details of the squeezing parts shown in Fig. 7,

Fig. 10 shows a perspective view of the squeezing parts of a very large end closure device similar to that shown in fig. 7,

Fig. 11 shows a plane partial view of another embodiment for the squeezing parts of an end closure device according to the invention - as seen from an external side thereof,

Fig. 12 shows a plane partial view of another embodiment for the squeezing parts of an end closure device according to the invention - as seen from an internal side thereof,

Fig. 13 shows a plane end view of the squeezing parts shown in Figs. 11 and 12,

Fig. 14 shows a perspective view of the squeezing parts shown in Figs. 11, 12 and

13,

Fig. 15 shows a perspective view of the squeezing parts shown in Figs. 11-14 - but seen from another angle,

Fig. 16 shows a perspective view of a cut through assemble of a tube sample and opposite end closure devices according to the invention,

Fig. 17 shows a plane view of an assemble of a tube sample and end closure devices according to the invention, Fig. 18 shows a plane sectional view through the assemble shown in Fig. 17,

Fig. 19 shows a plane view of an assemble of a tube sample and modified end closure devices according to the invention,

Fig. 20 shows a plane sectional view of the modified assemble shown in Fig. 19,

Fig. 21 shows a perspective view of the assemble shown in Fig. 19,

Fig. 22 shows a plane top view as seen from above of Fig. 19,

Fig. 23 shows a plane sectional view as seen along the sectional line B-B in Fig. 19,

Fig. 24 shows a plane sectional view as seen along the sectional line D-D in Fig. 19,

Fig. 25 shows a plane sectional view as seen along the sectional line E-E in Fig. 19,

Fig. 26 shows a plane enlarged sectional view of the details in circle C of the upper right corner of Fig. 20,

27 shows a plane view of parts of an end closure device shown in Figs. 19-21,

28 shows a perspective view of a part of an end closure device similar to that of Fig. 27,

29 shows a plane end view of the part of an end closure device shown in Fig. 28, and

Fig. 30 shows a perspective sectional view cut through assemble of a tube sample and modified end closure devices according to the invention.

Detailed Description of the Invention

In Figs. 1-3 is shown an embodiment for an end closure device 2 according to the invention comprising a dome-shaped end cap 4, a tube sample 6 and a squeezing part 8 divided into two parts 10 each extending through 180° around an end part 12 of the tube sample 6 and a collar part 14 of the dome-shaped end cap 4. Each of the squeezing parts 10 consists of a number of interconnected plate elements 16, which in this embodiment are placed with some internal distance and held together by means of external, radial connection means 18 and radial connection flanges 20 at the opposite ends of each 180° parts 10. Said external, radial connection means 18 also extends axially at the outside of said collar part 14 and abut with this in order to hold the dome-shaped end cap 4 in position in relation to the squeezing parts 10.

Most of the same parts are shown in Figs. 4-6 showing a squeezing part 8 comprising two 180° squeezing parts 10 with radial connection flanges 20 and external, radial connection means 18. At the middle of each squeezing parts 10 being arranged lifting eyes 22 adapted for use when handling the squeezing parts 10 by means of a crane or other lifting aggregate.

In Figs. 7-10 is shown a possible larger squeezing part 24 consisting of two squeezing parts 26 built-up similar to that of the squeezing parts 10 (Figs. 4-6) except from the fact that the squeezing parts 26 are made without internal distances between the respective plate elements forming the piled-up squeezing parts 26. As seen most clearly in Figs. 7, 9 and 10 the every second of the plate layers of the piled-up squeezing parts have minor internal diameter, whereby there in every second layer is established pro- jecting edges to improve skid-proof contact between the outside wall of a tube sample and the internal side of the respective squeezing parts 26.

Figs. 11-15 show still another embodiment of a 45° squeezing part 28 where some of the plate elements of the piled-up plate elements at the internal edges are provided with tooth 29 to improve skid-proof contact with the outside wall of a tube sample.

Figs. 16-18 show an embodiment of an assemble of a tube sample during the pressure test thereof, where use are made of squeezing parts 28 similar to them shown in Figs. 11-15.

Figs. 19-26 show an modified embodiment of an assemble of a tube sample during the pressure test thereof, where the 45° squeezing parts 30 are provided with external, axial extending bolts 32 used to connect and hold a dome-shaped end cap 34 in place in relation to already mounted squeezing parts 30 by means of simple mutters 36 (Fig. As seen more clearly in Figs. 27-29 the 45° squeezing parts 30 are also at internal plate edges provided with tooth to ensure skid-proof contact with the outside wall of a tube sample.

Fig. 30 shows a perspective sectional view through assemble of a tube sample during the pressure test thereof.

It shall be emphasized that the new and inventive principle according to the invention may be further modified with the main scope of the invention namely to provide for a more easily, quick and cheap production of end closure devices for use when testing polymer tubes.

In this connection it is indeed important that the very expensive combined end clo- sures with integrated end caps made from solid moulded and milled aluminium bronze may be simply be substituted by an improved end closure according to the present invention, where at least the squeezing parts may be made from cheaper laser cut piled-up layers of plate material such as stainless steel, that is without the need of very expensive and time consuming milling operation.

By the concept of the present invention it becomes possible to vary both the internal configuration and the thickness of the piled-up plate members forming at least the squeezing parts of the end closure device. In other words it would be possible to built- up squeezing parts with any possible internal configuration without using milling tool operations or machining at all.