COUPLING DEVICE AND COMBINATION AND ASSEMBLY THEREOF WITH A TUBE

Abstract

The invention relates to a coupling device for a tube having a Palladium-based membrane deposited thereon, for use in separation and purification of hydrogen in a hydrogen separator or reactor. The coupling device has an inlet for gas and configured to couple said tube to the inlet; a body part with a cylindrical opening for receiving the tube and for receiving gas flow to the inlet; a nut, the body part and the nut being configured such that the nut can be screwed onto the body part at the opening; a stack of at least two sealing rings. The body part, the nut and sealing rings are configured such that the tube extends through an axial end portion of the nut, the sealing rings into the opening such that, in use, the sealing rings are compressed axially as a result of screwing the nut onto the body part so that the sealing rings sealingly engage the tube.

Claims

1. A coupling device (10) for a tube (12) having a Palladium-based membrane deposited thereon, the tube for use in separation and purification of hydrogen in a hydrogen separator or reactor, the coupling device having an inlet (14) for a gas and configured to couple said tube to the inlet so that the gas can be supplied via the inlet into the tube, the coupling device comprising: a body part (5) with a cylindrical opening (6) for receiving the tube, the opening being arranged to receive gas flow to the inlet; and a nut (1), wherein the body part and the nut being configured such that the nut can be screwed onto the body part at the opening; the coupling device further having a stack (16) of at least two sealing rings (3, 4) provided between an end portion (20) of the body part surrounding the opening and an axial end portion (18) of the nut, wherein the body part, the nut and the stack of sealing rings are configured such that the tube extends through the axial end portion of the nut, through the stack of sealing rings and into the opening such that, in use, the stack of sealing rings is compressed in an axial direction (8) of the stack as a result of screwing the nut onto the body part so that the sealing rings sealingly engage a circumferential surface (11) of the tube.

2. Coupling device according to claim 1, wherein the stack (16) of sealing rings (3, 4) is a stack of two to eight sealing rings.

3. Coupling device according to claim 1, wherein the sealing rings (3, 4) are made of graphite, mica or copper.

4. Coupling device according to claim 1, wherein sealing rings (3, 4) of the stack (16) are square or rectangular shaped O-rings.

5. Coupling device according to claim 1, further comprising a metal ring (2) on top of the stack of sealing rings (3, 4), the ring (2) being arranged between the axial end portion (18) of the nut and the stack (16), so that a compressive force is exerted from the axial end portion of the nut to the stack of sealing rings via the metal ring.

6. Coupling device according to claim 1, wherein a sealing ring (4) of the stack (16) of sealing rings (3, 4), which sealing ring (4) in use contacts the end portion (20) of the body part (5) surrounding the opening (6), is a square or rectangular shaped O-ring having an axially protruding tapered ridge (22), facing the end portion (20) of the body part, wherein the end portion of the body part has a correspondingly tapered or chamfered portion (24) for receiving therein the ridge (22).

7. Coupling device according to claim 1, wherein the body part (5) and/or the nut (1) are made of a stainless steel or a low carbon alloy.

8. Coupling device according to claim 1, wherein threads (26) on the nut (1) and/or on the body part (5) have a coating made of silver or graphite, the threads arranged to screw the nut on the body part.

9. Combination of a coupling device (10) according to claim 1, and a tube (12) having a Palladium-based membrane deposited thereon, for use in separation and purification of hydrogen in a hydrogen separator or reactor.

10. The combination of claim 9, wherein the tube (12) is porous.

11. An assembly (100) comprising a coupling device (10) according claim 1, and a tube (12) having a Palladium-based membrane deposited thereon, for use in separation and purification of hydrogen in a hydrogen reactor, wherein the tube extends through the axial end portion of the nut, through the stack of sealing rings and into the opening, wherein the stack of sealing rings is compressed in an axial direction of the stack as a result the nut being screwed onto the body part so that the sealing rings sealingly engage a circumferential surface of the tube.

12. The assembly (100) of claim 11, wherein the tube (12) is porous.

13. The assembly (100) of claim 12, wherein the tube (12) is made of a ceramic material.

14. The combination of claim 10, wherein the tube (12) is made of a ceramic material.

15. Coupling device according to claim 2, wherein the stack (16) of sealing rings (3, 4) is a stack of three to five sealing rings.

16. Coupling device according to claim 15, wherein the stack (16) of sealing rings (3, 4) is a stack of four sealing rings.

17. Coupling device according to claim 6, wherein the axially protruding tapered ridge (22) is a circumferential ridge.

18. Coupling device according to claim 6, wherein the ridge and the tapered portion are dimensioned such that the ridge exerts a force having a radial component on the tapered portion as a result of axial compression of the sealing ring (4).

Description

[0024] The present invention is described hereinafter with reference to the accompanying schematic drawings in which an embodiment of the present invention are shown and in which like reference numbers indicate the same or similar elements.

[0025] FIG. 1a shows, in 3-dimensional view, an example of a coupling device according to the present invention;

[0026] FIG. 1b shows, in 3-dimensional exploded view, individual components of the coupling device of FIG. 1a;

[0027] FIG. 1c shows a bottom view of the coupling device of FIG. 1a;

[0028] FIG. 2a shows section A-A of FIG. 1c, in 3-dimensional view;

[0029] FIG. 2b shows cross-section A-A of FIG. 1c;

[0030] FIG. 2c shows cross-section B-B of FIG. 1c;

[0031] FIG. 2d shows detail IId of FIG. 2c;

[0032] FIG. 3a shows, in plan view, a top ring of the coupling device of FIG. 1a;

[0033] FIG. 3b shows section IIIb-IIIb of FIG. 3a;

[0034] FIG. 4 shows, in front view, an example of an assembly according to the present invention, connected to an external tube;

[0035] FIGS. 5a and 5b show components of a prior art coupling;

[0036] FIGS. 6a and 6b show components of a prior art coupling and membrane; and

[0037] FIG. 7 shows a graph of tests of a prior art coupling and membranes.

[0038] The dimensions of the sealing, that means of the coupling device, depend on the membrane, that means of the tube having the membrane deposited thereon. FIGS. 1a-3b show an example of a coupling device 10 according to the invention, for 14 mm membranes. The same shape can be used from membranes of different size starting from 6 mm diameter. In embodiments, the coupling device is for use with tubes having an outer diameter in the range of 5 to 50 mm.

[0039] FIGS. 1a-3b show a coupling device 10 for a tube 12 having a Palladium-based membrane deposited thereon. The tube 12 is for use in separation and purification of hydrogen in a hydrogen separator or reactor. The tube 12 is porous and preferably made of a ceramic material. The coupling device 10 has an inlet 14 for a gas and configured to couple said tube 12 to the inlet 14 so that the gas can be supplied via the inlet 14 into the tube 14. The supply of gas towards the inlet 14 may take place via an external tube 13 which is connected to the inlet 14 of the coupling device 10, as FIG. 4 shows.

[0040] The coupling device 10 comprises a body part 5 with a cylindrical opening 6 for receiving the tube 12. The opening 6 is arranged to receive gas flow to the inlet 14. The coupling device 10 also comprises a nut 1, wherein the body part 5 and the nut 1 are configured such that the nut 1 can be screwed onto the body part 5 at the opening 6. The body part 5 and the nut 1 are made of a stainless steel or a low carbon alloy. The material of the nut 1 and of the body part 5 may be Inconel 625. Threads 26 on the nut 1 and on the body part 5 may have a coating made of silver or graphite, the threads 26 arranged to screw the nut on the body part.

[0041] The coupling device 10 further has a stack 16 of at least two sealing rings 3, 4, in the example shown in the figures a number of three sealing rings 3 and one sealing ring 4, the stack 16 being provided between an end portion 20 of the body part 5 surrounding the opening 6 and an axial end portion 18 of the nut 1. The stack may have two to eight sealing rings, preferably three to five sealing rings, preferably four sealing rings as is the case in the example shown in the figures. The sealing rings 3, 4 are made of graphite but may also be made of mica or copper. The sealing rings 3, 4 of the stack 16 are rectangular, about square shaped, O-rings.

[0042] The body part 5, the nut 1 and the stack 16 of sealing rings 3, 4 are configured such that the tube extends through the axial end portion 18 of the nut, through the stack 16 of sealing rings and into the opening 6 such that, in use, the stack 16 of sealing rings 3, 4 is compressed in an axial direction 8 of the stack 16 as a result of screwing the nut 1 onto the body part 5 so that the sealing rings 3, 4 sealingly engage a circumferential surface 11 of the tube 12.

[0043] At least in the example shown, the coupling device 10 further comprises an optional metal ring 2 on top of the stack 16 of sealing rings 3, 4. The material of the ring 2 may be stainless steel. The ring 2 is arranged between the axial end portion 18 of the nut 1 and the stack 16, so that a compressive force is exerted from the axial end portion 18 of the nut 1 to the stack 16 of sealing rings 3, 4 via the metal ring 2. Also, the sealing ring 4 of the stack 16 of sealing rings 3, 4, which sealing ring 4 in use contacts the end portion 20 of the body part 5 surrounding the opening 6, is a rectangular shaped O-ring having an axially protruding tapered ridge 22, which is a circumferential ridge as in particular FIG. 3b shows, facing the end portion 20 of the body part 5. The end portion 20 of the body part 5 has a correspondingly tapered or chamfered portion 24 for receiving therein the ridge 22. See FIG. 2d. The ridge 22 and the tapered portion 24 are dimensioned such that the ridge exerts a force having a radial component on the tapered portion as a result of axial compression of the sealing ring 4.

[0044] In the example shown in the figures, the following dimensions may be chosen for use of the coupling device with a tube having an outer diameter of 14 mm, that means with a membrane of 14 mm. The specific dimensions are merely provided as an example. Other dimensions may be suitably chosen dependent on the size of the membrane and/or intended application. L1 may be a size 34 hex nut (L2 may in that case be 39.26 mm); L3 may be 3 mm; L4 may be 7 mm; L5 may be 13 mm; L6 may be 83 mm; L7 may be 55 mm; L8 may be 7.5 mm (or between 7.3 and 7.7 mm).; L9 may be 5 mm (or between 4.8 and 5.2 mm); T1 may be a 28×1.5 thread (outer thread on the body part and corresponding inner thread on the nut); D1 may be 34 mm; D2, being the inner diameter of ring 4, may be 14.5 mm (or between 14.5 and 14.7 mm); D3, being the outer diameter of ring 4, may be 24 mm (or between 23.8 and 24 mm); diameter D4 may be 21 mm (or between 20.8 and 21 mm); angle a1 may be 43 degrees; angle a2 may be 40 degrees (or between 39.5 and 40.5 degrees). Each of the rings 3 may have an inner diameter of 14.5 mm (or between 14.5 and 14.7 mm), an outer diameter of 24 mm (or between 23.8 and 24 mm) and a thickness of 5 mm (or between 4.8 and 5.2 mm).

[0045] FIG. 4 shows an assembly 100 comprising the coupling device 10 and the tube 12 having a Palladium-based membrane deposited thereon, for use in separation and purification of hydrogen in a hydrogen reactor. The tube extends through the axial end portion of the nut, through the stack of sealing rings and into the opening, wherein the stack of sealing rings is compressed in an axial direction of the stack as a result the nut being screwed onto the body part so that the sealing rings sealingly engage a circumferential surface of the tube. The top part of the sealing, i.e. the coupling device (at the inlet) may be welded to an external tube 13 of any dimension for easy installation inside the reactor. A potential commercial use of the invention is membrane sealing for membrane separation and membrane reactors.

[0046] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. The foregoing description provides embodiments of the invention by way of example only. The scope of the present invention is defined by the appended claims. One or more of the objects of the invention are achieved by the appended claims.