WO2018169406A1

WO2018169406A1 - Pipe coupling to connect two pipes and methods for connecting two pipes.

Info

Publication number: WO2018169406A1
Application number: PCT/NO2018/000007
Authority: WO
Inventors: Hugo OLUFSEN; Rolf Johan BJØRKLUND
Original assignee: Liitos As
Priority date: 2017-03-15
Filing date: 2018-03-15
Publication date: 2018-09-20
Also published as: NO20170384A1; NO347639B1

Abstract

Pipe coupling to connect two pipes (6, 6 ') at the pipe ends (5, 5 '), comprising; two screw sleeves (3, 3 ') with external threads, a main sleeve (1) with internal threads at each end, two sealing rings (2.2 '), where the pipe coupling wherein one of the screw sleeves (3) and one of the sealing rings (2) is adapted to be pulled on to the first pipe end (5) so that the sealing ring (2) is positioned at the first pipe end (5) that is opposing the second pipe end (5 '), and where the second screw sleeve (3 ') and the second sealing ring (2 ') in the same way is adapted to be pulled onto the second pipe end (3 ') such that the seal ring (2 ') is positioned at the second pipe end (5 ') opposing the first pipe end (5), and where the main sleeve (1) has a larger diameter than the screw sleeves (3, 3 ') and is adapted such that the sealing rings (2,2 ') and screw sleeves (3, 3 ') which are positioned on the pipes (6, 6 '), can be pulled into the main sleeve (1) toward the middle of the main sleeve (1).

Description

Pipe coupling to connect two pipes and methos for connecting two pipes. Field of the invention

The present invention concerns a pipe coupling to connect two pipes and a method for connecting two pipes.

Background of the invention

Different pipe couplings are known. By use of welding materials are joined by fusion. Welding is done by that contact surfaces of the workpieces, often along with a fill material (filler rod or welding electrode) is warmed to melting, and float together by cohesion. Repairing or replacement of welded pipes is demanding, concerning the need of both labor and equipment. Welding cannot be done in areas where there are flammable liquids or gases present. A pipe joint that replaces the welding work for joining of pipes is therefore beneficial.

Some known solutions in equipment that use mechanisms as couplings in replacement to welding metal pipes use sealing rings of synthetic materials, plastic, nylon, plastics that are not resistant to heat, or that the pipes are threaded/alternative use of flange with gaskets, plastics. All of these options have short lifetime, as well as the very limited resiliency for high temperatures. Where such conditions with high temperatures can occur, for example, by fire or the use of steam, the coupling can be used as the materials are the same or similar as the pipe material/metal. Known solutions are therefore not suitable for use in all environments.

Well known press couplings and fittings of copper are produced for thin pipes and are not suitable for used in steel pipes. These products must also be used together with support sleeves in the pipe.

PCT application WO2007035308 discloses a threaded pipe connection. The pipe coupling is suitable for long risers in oil and gas production.

Patent document NO 162981 discloses a coupling to pipes with helical threaded conical surfaces of a sleeve and a socket. It is especially designed for connection of pipes, where it is difficult to make rotation at the joint. Assembly of known solutions can be very time consuming and mounting costs are high. In the case of pipe rupture, repairing will thus be very time consuming and expensive.

The purpose of the present invention is to provide a device and method that solves the aforementioned problems while retaining the benefits of prior art.

Summary of the invention

The above-mentioned problems are solved by the present invention by a device and a method as described the claims. This is achieved according to the invention by providing a pipe coupling to connect two pipes at the pipe ends comprising; two screw sleeves with external threads, a main sleeve with internal threads at each end, two sealing rings, where the pipe coupling is characterized by that one of the screw sleeves and one of the sealing rings is adapted to be pulled onto the first pipe end so that the sealing ring is positioned at the first pipe end that is opposing the second pipe end, and where the second the screw sleeve and the second sealing ring in the same way is adapted to be pulled on to the second pipe end such that the seal ring is positioned at the second pipe end opposing the first pipe end and where the main sleeve has a larger diameter than the screw sleeves and is adapted such that the sealing rings and screw sleeves which are positioned on the pipes, can be pulled into the main sleeve toward the middle of the main sleeve.

In another aspect the present invention relates to a method for connecting two pipes, characterized by comprising; pulling a screw sleeve onto a first pipe end, and pulling a sealing ring onto the first pipe end, and pulling a second screw sleeve onto a second pipe end, and pulling a second sealing ring on the second pipe end, and to lead sealing rings and screw sleeves into a main sleeve toward the middle of the main sleeve, and to connect pipes by screwing the screw sleeves together and the main sleeve with, respectively exterior and interior threads, so that the pipes are connected with a unique mechanical strength in the joint.

Brief overview of the drawings

The invention will be described in greater detail below be means of an exemplary embodiment with reference to the accompanying drawing, in which:

Figure 1 shows the pipe with the pipe coupling according to present invention. Figure 2 shows an exploded view of the different parts to the pipe coupling according to the present invention. Figure 3 shows the main sleeve of the pipe coupling according to the present invention.

Figure 4 shows the screw sleeve of the pipe coupling according to the present invention.

Figure 5 shows a cross-section of the pipe with the pipe coupling according to the present invention.

Detailed description

The present invention will now be described in further detail with support in the drawings. A pipe coupling according to the present invention is shown in Figure 1. The various parts of the pipe coupling are also shown in the exploded view in Figure 2. As illustrated on the drawings the pipe coupling consists of only five parts; one sleeve 1, two sealing rings 2, and two screw sleeves 3. All the parts are made of well-known materials mainly steel and other alloy.

The invention enables joining and repairing of pipes without the use of the welding. Changing or repairing of pipes by use of known methods is both labor and equipment demanding, and they cannot be welded in an area where there are flammable liquids or gases. The use of the present invention will be beneficial during all environmental circumstances

The pipe coupling according to the invention is easy to mount due to its design and because it consists only of 5 parts. It includes two screw sleeves 3, 3 ' as illustrated Figure 4. The screw sleeve has exterior threads and is adapted to be screwed together with the main sleeve 1 which has internal threads. The main sleeve 1 with internal threaded at each end is shown in Figure 3. Two pipes are connected together by that a screw sleeve 3 and a sealing ring 2 is adapted to be pulled onto the first pipe end 5, where sealing ring 2 is positioned at the pipe end 5 which is opposing the second pipe end 5 ' as illustrated in Figure 1. The second screw sleeve 3 ' and the second sealing ring 2 ' is correspondingly customized to be pulled onto the second pipe end 5 ' so that sealing ring 2 ' is positioned at the second pipe end 5 ' opposing the first pipe end 5, as shown in Figure 1. The main sleeve 1 that has larger diameter than the screw sleeves 3, 3 ' are designed such that sealing rings ' 2,2 and the screw sleeves 3, 3 ', which are arranged on the pipes 6, 6 ' can be pulled into the main sleeve 1 to the middle of the main sleeve. Screw sleeves 3, 3 ' and the main sleeve are screwed together by the exterior and interior threads, and are screwed tightened together by use of e.g.

spanners, such that the pipes 6, 6 ' are firmly jointed. The screw sleeves are tightened by the spanners, or other suitable tool depending on tool interface, according to a given torque. The pipes are thereby jointed together without achieving plastic deformation and thus no flow-through obstructions.

The inner diameter of the screw sleeves 3, 3 ' is about the same as the external diameter of the pipes 6, 6 ', i.e. the minimum inner diameter of the screw sleeves 3, 3 ' is 10 μιη larger than the maximum outer diameter of the pipes 6, 6',.

All coupling parts are preferably made of metal, eg. as stainless steel and/or other high tensile material including plastics, depending on application/pipe. The whole mechanical piping coupling can be fixed using only simple tools. Assembling of known solutions can be very time consuming. The assembling time is significantly reduced by the use of the pipe coupling according to the present invention. The two pipes 6, 6 ' are as mentioned connected by pulling the screw sleeve 3 and sealing ring 2 into the first pipe end 5. Correspondingly the second screw sleeve 3 ' and the second sealing ring 2 ' are pulled onto the second pipe end 5 '. The sealing rings 2,2' and screw sleeves 3, 3 ' are thereafter pulled into the main sleeve 1 to the middle of the main sleeve 1. The pipes 6, 6 ' are thereafter connected together by screwing the screw sleeves 3,3 ' and the main sleeve 1 firmly together and the pipes 6, 6 ' are thereby connected with a unique mechanical strength in the joint. By use of the present invention it will be a relatively short mounting time and the pipe coupling can be used and mounted in all environments. Coupling time by use of the pipe coupling according to the present invention will be 10-20 minutes per unit, which is very fast compared to what is required with other solutions. Assembly costs are also significantly reduced.

In more detail the method for connecting two pipes 6, 6 ' comprises the steps of measuring and marking half the length of the main sleeve 1 from each pipe end 5, 5' and thereafter pulling the first screw sleeve 3 with its tool interface side first onto the first pipe end 5. The first sealing ring 2 is then pulled with its flat side against the screw sleeve 3 onto the first pipe end 5. Correspondingly the second screw sleeve 3 ' is pulled with its tool interface first onto the second pipe end 5 ' and the second sealing ring 2 ' is pulled with its flat side against the screw sleeve 3 on the second pipe end 5 '. Thereafter inserting the sealing rings 2,2' and the screw sleeves 3, 3' into the main sleeve 1 towards the midpoint of the main sleeve 1 such that the pipe ends 5, 5' meet at the middle. The pipes 6, 6 ' are connected by screwing together the screw sleeves 3,3' by a rotating torque from the clamping tool and the main sleeve 1 with external and internal threads respectively, such that the sealing rings 2, 2 ' shrink against the pipes 6, 6' and forms a friction joint. By screwing the tool interface part, the sealing is thereby pressured inwards. The screw sleeves 3, 3 ' are screwed and tightened with a suitable tool to reach a particular torque and thereby sealing the coupling.

The pipe coupling according to the invention is suitable where there is a need for a rigid, durable pipe join that to the greatest possible extent can centering the fluid flow through the coupling, with the very little resulting cavitation.

The diameter of the screw sleeves is within 1 % oversize of the pipe diameter, with a screw sleeve length that narrowly exceeds the pipe diameter. This contributes to give the coupling a unique mechanical strength. The coupling is suitable for steel pipes in all dimensions not limited to, but also beyond 32 mm (prototype ref.). The coupling is suitable for use in a range of materials including plastics and metals, where limitations are tensile strength and deformation of materials. The pipe coupling according to the invention is unique in physical strength where the joint is supported in the sleeve in a length exceeding 2 times the pipe diameter. The coupling is very well suited for all types of steel pipes as structural pipes, steam pipes in all dimensions, and it endures all pressure requirements for pressures up to 30 bar for mild and high tensile steel and metals. The pipe coupling can be produced in various dimensions, and it fulfills the fire requirements when produced in steel and other appropriate metals.

The pipe coupling according to the invention is reliable, do not need support and is a good option to welding. The pipe coupling will be tight at high pressure and over a long life time, and cavitation is also minimized. The joint covers all requirements of law and all classifications of temperatures. This is shown in results from pressure tests of the pipe coupling that are carried out.

The pipe coupling is robust and there is no need for maintenance after installation. It is easy to use, easy to mount and material costs can be minimized in terms of strength. By pipe rupture in the process industry, on ships, etc. the pipe coupling can still be used without middle stop, then as sliding sleeve. The pipe coupling will also be able to be used in pipe bend joint and T-coupling.

Embodiments shown on the drawings and disclosed in the description is not limiting, but intended only as examples. While the invention has been described with reference to specific examples and embodiments, the scope of the invention is determined by the accompanying claims.

Claims

1. Pipe coupling to connect two pipes (6, 6 ') at the pipe ends (5, 5 '), comprising; two screw sleeves (3, 3 ') with external threads, a main sleeve (1) with internal threads at each end, two sealing rings (2.2 '), where the pipe coupling is

characterized by that

one of the screw sleeves (3) and one of the sealing rings (2) is adapted to be pulled on to the first pipe end (5) so that the sealing ring (2) is positioned at the first pipe end (5) that is opposing the second pipe end (5 '), and where

the second screw sleeve (3 ') and the second sealing ring (2 ') in the same way is adapted to be pulled onto the second pipe end (5 ') such that the seal ring (2 ') is positioned at the second pipe end (5 ') opposing the first pipe end (5), and where the main sleeve (1) has a larger diameter than the screw sleeves (3, 3 ') and is adapted such that the sealing rings (2.2 ') and screw sleeves (3, 3 ') which are positioned on the pipes (6, 6 '), can be pulled into the main sleeve (1) toward the middle of the main sleeve (1).

2. The pipe coupling according to claim 1, where screw sleeves (3, 3 ') and the main sleeve (1) is adapted to be screwed together by the exterior and interior thread, and screwed together and tightened by use of e.g. spanners or similar appropriate tool depending on interface, so that the pipes (6, 6 ') are connected.

3. The pipe coupling according to any of claim 1 or 2, where the minimum inner diameter of the screw sleeves (3, 3 ') is 10 μιη larger than the maximum outer diameter of the pipes (6, 6').

4. The pipe coupling according to any of claim 1-3, where all the couplings elements consist of metal.

5. The pipe coupling according to any of claim 1-4, where the couplings elements consist of stainless steel and/or any other high tensile material, including plastics depending on application.

6. Method for connecting two pipes (6, 6 '), characterized by comprising; pulling a first screw sleeve (3) onto a first pipe end (5), and

pulling a sealing ring (2) onto the first pipe end (5), and

pulling a second screw sleeve (3 ') onto a second pipe end (5 '), and

pulling a second sealing ring (2 ') on the second pipe end (5 '), and

leading the sealing rings (2.2 ') and screw sleeves (3, 3 ') into a main sleeve (1) toward the middle of the main sleeve (1), and

connecting the pipes (6, 6 ') by screwing the screw sleeves (3,3 ') and the main sleeve (1) together with respectively exterior and interior threads, so that the pipes are (6, 6 ') connected with a unique mechanical strength in the joint.

7. The method for connecting two pipes (6, 6 ') according to claim 6, comprising the steps of; measuring and marking half the length of the main sleeve (1) from each pipe end (5, 5'), and

pulling the first screw sleeve (3) with its tool interface (7) first onto the first pipe end (5), and

pulling the first sealing ring (2) with its flat side against the first screw sleeve (3) onto the first pipe end (5), and

pulling the second screw sleeve (3 ') with its tool interface (7') first onto the second pipe end (5 '), and

pulling the second sealing ring (2 ') with its flat side against the second screw sleeve (3') onto the second pipe end (5 '), and

inserting the sealing rings (2,2 ') and the screw sleeves (3, 3') into the main sleeve (1) towards the midpoint of the length of the main sleeve (1) such that the pipe ends (5, 5') meet at the middle of the main sleeve (1) and

connecting the pipes (6, 6 ') by screwing together the screw sleeves (3,3'), by a rotating torque from the clamping tool, and the main sleeve (1) with external and internal threads respectively, such that the sealing rings (2, 2 ') shrink against the pipes (6, 6') and forms a friction joint.

8. The method according to claim 6 or 7 where the screw sleeves (3, 3 ') are screwed and tightened with a suitable tool to reach a particular torque and thereby sealing the coupling.