A METHOD FOR MAKING A BALL VALVE FOR REGULATING A FLUID, A BALL VALVE AND A WELDING TOOL FOR HOLDING AND HANDLING VALVE PARTS

Abstract

Various embodiments of the present disclosure are directed to a method for producing a ball valve for regulating a fluid. In one example embodiment, the method includes the steps of: providing first and second housing parts of the valve housing, said first and second housing parts each including at least a central housing part and a connection end; providing a valve element shaped as a ball with at least one through-going aperture; arranging the first and second housing parts with the respective central part ends facing towards each other, and further arranging the ball at a position inside an inner space defined by the respective central parts; and welding the first and second housing parts together using a welding tool while performing an interrelated rotation about an axial rotation axis between the position of the first and second housing parts and the position of the ball.

Claims

1. A method for producing a ball valve for regulating a fluid, the ball valve including a valve housing with a central part and with two connection ends, the connection ends extending away from the central part, further including a valve element arranged within the central part, wherein the valve element is arranged relative to one or more valve seats in the central part of the valve housing, and wherein the method of producing the valve housing includes the following steps: providing at least a first housing part and a second housing part of the valve housing, said first and second housing parts each including at least a central housing part and a connection end, providing a valve element shaped as a ball with at least one through-going aperture, arranging the first and second housing parts with the respective central part ends facing towards each other, and further arranging the ball at a position inside an inner space defined by the respective central parts, and welding the first and second housing parts together using a welding tool while performing an interrelated rotation about an axial rotation axis between the position of the first and second housing parts and the position of the ball and a welding laser or welding torch of the welding tool to provide a valve housing with a single welding seam arranged at the central part of the valve housing.

2. The method according to claim 1, wherein the single welding seam is made with laser welding.

3. The method according to claim 1, wherein the welding is performed from the inner space or an outer side of the central part.

4. The method according to claim 1, wherein the interrelated rotation is performed by: rotating the first and second housing parts relative to the fixed position of the ball and the welding laser or welding torch, and/or rotating the ball and the welding laser or welding torch relative to the fixed position of the first and second housing parts.

5. The method according to claim 1, wherein the first and second housing parts are identical in shape.

6. The method according to claim 1, wherein a valve seat is arranged in the first and/or the second housing parts prior to the assembly of the valve housing.

7. The method according to claim 1, wherein the ball is maintained in a rotating or fixed manner inside and relative to the central part, by means of the welding tool including an expandable mandrel configured and arranged to hold the ball, when the mandrel is inserted into the through-going aperture and then expanded, or an arm with an indexer configured and arranged to hold the ball, in a fixed position on the arm by the indexer engaging an indexer aperture in the ball.

8. The method according to claim 7, wherein the central part of the valve housing is configured and arranged to receive a protective gas through a connection that extends through the arm and/or through a connection end's opening.

9. The method according to claim 7, wherein the method further includes inspecting the single welding seam on the interior of the valve housing's central part using a camera arranged on the arm.

10. A ball valve for regulating a fluid, the ball valve comprising: a valve housing with a central part and with two connection ends, the connection ends extending away from the central part, wherein the central part includes a valve element shaped as a ball with at least one through-going aperture, and one or more valve seats arranged relative to the ball, and wherein the valve housing is configured and arranged to be assembled by a single welding seam provided centrally at the central part of the valve housing.

11. The ball valve according to claim 10, wherein the ball valve is a floating ball valve or a trunnion ball valve.

12. The ball valve of claim 10, wherein the ball further includes an indexer aperture, where said indexer aperture in the ball is adapted in size, shape and/or position to engage with an indexer of a welding tool.

13. A welding tool for holding and handling valve housing parts and a ball during welding, said welding tool comprises: holding means configured to hold the ball in a position inside a central part of a valve housing, and rotation means configured and arranged to perform an interrelated rotation about an axial rotation axis between a position of the valve housing parts and the position of the ball and the welding laser or welding torch.

14. The welding tool according to claim 13, wherein the holding means includes: an expandable mandrel which is configured and arranged to hold the ball when inserted into a through-going aperture and then expanded, or an arm with a radial bore in which an indexer is mounted, and where the indexer is configured to be slidable radially out of and/or into the radial bore by means of an indexing actuator arranged in the arm.

15. The welding tool according to claim 14, wherein the welding tool further includes one or more gas ducts configured and arranged for introduction and/or withdrawal of a protective gas into the valve housing's inner space.

16. The welding tool according to claim 14, wherein the indexer further includes a connecting bore for connecting at least one gas duct with the indexer's radial bore at least when the indexer is in the expanded position.

17. The welding tool of claim 14, wherein the rotation means for performing the interrelated rotation about the axial rotation axis includes a turret and a bearing, where the bearing is arranged to surround the arm, and where the turret is arranged to engage with an end of the valve housing so as to enable rotation of the valve housing parts.

18. (canceled)

19. The method according to claim 1, wherein the rotation axis coincides with a central longitudinal axis of the valve housing.

20. The welding tool of claim 14, wherein the rotation means for performing the interrelated rotation about the axial rotation axis includes a turret and a bearing, where the turret is arranged to surround the arm, and where the bearing is arranged to engage with an end of the valve housing so as to enable rotation of the ball and the welding laser or welding torch.

21. The welding tool according to claim 14, wherein the welding laser or welding torch and the indexer are aligned in a radial direction so that the indexer is held in a fixed position relative to a welding spot during welding.

Description

DESCRIPTION OF THE DRAWING

[0092] The invention will now be explained below with reference to the drawing, where:

[0093] FIG. 1 shows a prior art valve assembled with two welding seams in a cross sectional view,

[0094] FIG. 2 shows a valve with a valve housing according to the invention,

[0095] FIG. 3 shows the valve in FIG. 1 in a cross sectional view,

[0096] FIG. 4 shows a ball of a ball valve according to the present invention,

[0097] FIG. 5 shows a pre-shaped and pre-assembled valve housing part for making a valve according to the present invention,

[0098] FIG. 6a-c show steps in the process of welding together of the valve housing parts shown in FIG. 5, and

[0099] FIG. 7 shows an alternative embodiment of assembling the valve housing parts according to the invention.

[0100] In the explanation of the figures, identical or corresponding elements will be provided with the same designations in different figures. Therefore, no explanation of all details will be given in connection with each single figure.

DETAILED DESCRIPTION OF THE INVENTION

[0101] FIG. 1 shows a traditional ball valve in a cross sectional view. In the present FIG. 1 ball valve is a floating ball valve. The valve has a valve housing 2 with connection ends 4 attached to the central part 3 where the connection ends 4 face in opposite longitudinal directions of the valve housing 2. Traditional valve housings are welded together by a welding seam at the transit area 2c between the central part 3 and the each of the connection ends 4a,4b respectively.

[0102] FIG. 2 shows a valve 1 according to the present invention. The valve also has a valve housing 2 with connection ends 4 attached to the central part 3.

[0103] The valve in FIG. 2 is made with a single welding seam 9 that surrounds the central part 3. In FIG. 2 a valve spindle is arranged in a spindle stub 8. Thus the valve housing in FIG. 1 is made from two pre-formed housing parts 2a,2b as shown in FIG. 5. The housing half parts 2a, 2b are pre-formed as described further above. Each housing part has valve seat 7 installed prior to assembly of the valve housing by welding together the housing half parts 2a, 2b at the welding end 3c (see also FIG. 5).

[0104] FIG. 3 shows a cross section of the valve in FIG. 2 (valve spindle and spindle stub 8 are not disclosed in FIG. 2). The ball 5 shown in FIG. 3 is a ball 5 with at least a through-going passage 6 that allows a fluid flow through the ball body 5c. The ball is also shown in FIG. 4. The ball body 5c comprises through-going aperture 6 and a spindle attachment opening 5a. An indexer aperture 5b is also arranged in the ball 5. The function of the indexer aperture 5b is described further below. In FIG. 4, the indexer aperture 5b is shown as oval although other shapes are possible as also discussed above, as long as the indexer aperture 5b allows the indexer 12 to pass into the indexer aperture 5b and fix the ball body 5c firmly in a non-rotating manner as also discussed further below.

[0105] As shown in FIG. 3 the ball body 5c is positioned inside the central part 3 of the valve housing 2 and is held in position between the valve seats 7. The welding seam 9 is arranged centrally on the valve housing's central part 3.

[0106] Next the welding tool and the method of producing the valve is described with reference to FIGS. 6a-6c.

[0107] The welding tool 10 is configured for holding and handling the valve housing parts 2a,2b and the ball 5 during welding. The welding tool comprises an arm or a shaft 11 with a radial bore 11a in which an indexer 12 is arranged. The indexer 12 is slidably arranged inside the arm 11 and configured to slide radially out of and/or into the radial bore 11a by means of an indexer actuator 13 arranged in the arm 11 as illustrated with arrow 12d in FIG. 6b.

[0108] The welding tool further comprises rotation means 15, 17 for rotating the housing parts about the rotation axis 18 that is coinciding with the arm's 11 axial axis, see arrow 18a on FIG. 6c.

[0109] Thereby, the ball 5 can be held fixed while the housing parts 2a,2b can be rotated during the welding procedure. This further enables that the welding seam is uniform and of uniform high quality. In addition, the automated handling of the valve housing parts during welding further enables that the welding procedure can be automated in a simple, low cost and effective manner. The automation of the welding procedure may e.g. comprise use of robots to perform mounting of valve parts in the welding tool and/or to perform the welding step.

[0110] The rotation axis of the valve housing parts and the longitudinal axis/axial direction of the arm 11 are in principle coinciding and is shown in FIGS. 6a and 6c as line 18.

[0111] Alternatively, the rotation means 15, 17 can be arranged so that the arm 11 and thus the ball 5 are rotating about rotation axis 18 instead of the housing parts 21, 2b. Thereby, the housing parts 2a, 2b can be held fixed while the ball 5 can be rotated during the welding procedure. This also enables that the welding seam is uniform and of uniform high quality.

[0112] The indexer 12 is arranged to be slide radially out of and/or into the radial bore 11a by means of an indexing actuator 13 arranged in the arm 11. As discussed above, the shape of the indexer actuator is not important and may e.g. alternatively comprise a pneumatically, electrically or hydraulically driven indexer actuator, e.g. a piston or cylinder may be used. Thus, the indexer actuator shown in FIGS. 6a-6c is merely an example of a possible construction of the indexer actuator.

[0113] In FIGS. 6a-6c, the indexer actuator is movable in axial direction 18 as illustrated with arrow 13b in FIG. 6b. Thereby the wedged surface 13a on the indexer actuator 13 pushes the indexer radially out of the radial bore 11a in the arm 11 by means of its contact with a corresponding sliding surface 12b on the inner end of the indexer 12. Thus, when extended from the arm 11, the indexer actuator 13 pushes the indexer 12 radially outwards (see arrow 12d in FIG. 6b) as the indexer 12 slides up the wedged surface 13a on the indexer 13. When retracting the indexer actuator 13, the indexer 12 slides back down the wedged surface 13 on the indexer actuator 13 and is withdrawn into the radial bore 11a in the arm 11.

[0114] The indexer 12 is held in a fixed position below the spot 9a where welding occurs. The indexer 12 is thus able to collect any melted material from the welding step in a bore 12a extending radially inward in the indexer body 12 (i.e. radially inwards in relation to the rotation axis). Thereby, the indexer 12 also holds the ball 5 in a fixed, non-rotating position during the welding procedure. The bore 12a in the indexer body is preferably cylindrical or conical as shown in FIGS. 6a-6c and thus provides a funnel-like member for collecting surplus melted matter. It is noted that the indexer 12 can be taken out of the radial bore 11a and replaced with a new indexer (or a cleaned indexer), e.g. if the indexer bore 12a is blocked by melted matter. It is noted that the funnel/conical shape of the bore 12a is preferred as the bore 12a is then easier cleaned for any melted metal caught herein.

[0115] The welding tool 10 further comprises rotation means 15,17 for rotating the valve housing parts 2a,2b about an axial rotation axis 18 and about the arm of the welding tool. This enables rotation of the housing parts 2a,2b during the welding procedure, while the ball 5 is held in fixed, non-rotation position on the arm.

[0116] The rotation means for rotating the valve housing parts about an axial rotation axis preferably comprises a turret 15 and a bearing 17 in FIGS. 6a-6c, the bearing 17 is arranged to surround the arm 11 and to support a support bushing 16 for holding a connection end 4a of a first valve housing part 2a. The turret 15 is arranged to engage with the opposite connection end 4b of the second valve housing part 2b. The reverse order is also possible, i.e. that the turret 15 is arranged to surround the arm 11 while the bearing 17 with the support bushing 16 is arranged at the opposite end valve housing 1 when arranged in the welding tool 10.

[0117] The turret 15 enables rotation of the valve housing parts 2a,2b in a rotation direction 18a during welding by rotating the first housing part 2a, and the bearing 16 supports the co-rotation of the second housing part 2b since the two housing parts are clamped between the bearing 17 with the support bushing 16 and the turret.

[0118] The welding laser or welding torch 10a is held in a fixed position, while the valve housing 2 rotates during welding of the welding seam 9 surrounding the central part 3 of the valve's housing 2. The reverse is equally possible, as the welding laser or welding torch may be rotated around the stationary valve housing 2 during the welding procedure while holding the indexer 12 under the area of the welding spot 9a (corresponding to the welding seam 9) at all the time. In this situation, the protective gas is preferably circulated inside the valve housing 2b by withdrawing the protective gas through the bores 12a, 12c in the indexer 12 and at least one bore in the arm, e.g. by suction as also outlined below. This enables that the indexer 12 is able to collect any melted surplus matter as the melted matter is sucked into the indexer bore 12a. Thus the indexer is also able to collect melted matter during welding even though the indexer's opening/bore 12a is angled downwards (during its rotation).

[0119] When welding is finished, the valve housing 2 will be aligned with the ball 5 so as to align the opening 8a in the valve housing for mounting of the spindle stub and a spindle 8 at the spindle mounting opening 5a in the ball 5.

[0120] The spindle stub with the spindle arranged herein can then be arranged in the opening 8a in the valve housing. After mounting the spindle stub and spindle 8, the spindle stub may be laser welded to the housing. This can be done by holding the laser welding torch in fixed position and rotate the laser welding tool about a the spindle stub's axis to provide a laser welded seam at the transit between the valve housing and the spindle stub.

[0121] When the indexer 12 is deactivated (i.e. withdrawn into the radial bore 11a in the arm of the welding tool, see FIG. 6a) it is noted that the ball 5 will be able to rotate together with the valve housing 2 as the valve seats 7 holds the ball 5 in position in relation to the valve housing 2.

[0122] The protective gas can be provided to the inner space 3b of the valve housing's central part 3 by several possible ways, such as through one or more bore/pipe connection(s) 14 through the arm and/or through a connection end's opening. The protective gas thus also serves as a backing gas during the welding step.

[0123] In a preferred variant, the protective gas is applied out through the indexer 12 as this ensures that protective gas is supplied very close to the welding area 9. Alternatively, the protective gas may be withdrawn through the bores in the indexer 12a,12b and the arm 14. This is possible if the indexer 12 further comprises a connecting bore 12c for connecting at least one gas duct 14 in the arm with the indexer's radial bore 12a at least when the indexer is in the expanded position as shown in FIGS. 6b-6c.

[0124] The welding tool may be provided with a camera 19, which is preferably mounted on the arm. The camera 19 is preferably directed in the opposite direction of the indexer. The camera is e.g. directed radially outwards and directed towards the spindle opening 5a in the ball 5 for attachment of the valve spindle 8. In this way, the camera can be connected to a computer with relevant software and is able to inspect the welding seam on the interior of the valve housing during the welding procedure. This improves the quality of the valves as the welding procedure can be adapted in case the camera inspection detects flaws or errors in the welding seam. The result will be a lower number of “off-spec” valves, and thus further reduced overall production costs.

[0125] FIG. 7 shows an alternative embodiment of the invention where the welding process is performed from the inner space of the valve housing 2. Here, the welding laser/torch 10a is arranged relative to the connection end 4b of the second housing parts 2b. The welding laser/torch 10a is connected to a power/energy source (not shown) also located outside the valve housing 2. A mirror 10b is arranged inside the inner space of the central part 3. The mirror 10b is aligned with the welding ends 3c of the first and second housing parts 2a, 2b and further with the welding laser/torch 10a. A welding beam, e.g. a laser beam, is projected from the welding laser/torch and reflected by the mirror 10b to form the welding seam 9.

[0126] The indexer 12′ is held in fixed position at the outer side of the valve housing 2 below the position 9a where the welding occurs. Alternatively or additionally, the indexer may be held in a fixed position at the inner space of the valve housing 2 below the welding spot 9a. This enables the indexer to collect any surplus material arising from the welding procedure so it cannot attach to the ball or the valve seats, seals etc.

[0127] The ball 5 is held in fixed, non-rotating position in the inner space of the valve housing 2. This is achieved by an arm 11′ extending into the connection 4a of the first housing part 2a. The arm 11′ has a free end shaped so that it faces the indexer aperture 5b of the ball 5 when inserted into the connection end. The end surface of the arm's free end may be flushed with the outer surface of the ball 5, or project slightly into the space between the ball 5 and the central part 3 of the valve housing.

[0128] In the present application, the term “approximately” is used which includes the tolerances seen as normal by the skilled in the art. For example, the term “approximately circular” is used, and “approximately” is here to be understood in the way that the skilled in the art visually perceives the shape as circular or substantially circular, besides including the tolerances seen as normal by the skilled in the art by possible measuring and determining the shape of the workpiece.

[0129] The invention is not limited to the above described embodiments and not to the embodiments shown in the drawings either, and the invention as specified and defined in the claims may be supplemented and modified in any way as suggested by a person skilled in the art.

LIST OF REFERENCE NUMBERS

[0130] 1. valve [0131] 2. valve housing [0132] a. first (half) housing part [0133] b. second (half) housing part [0134] c. transit area between central part and connection end [0135] 3 central part [0136] a. (half) part of central housing [0137] b. inner space of valve housing's central part [0138] c. welding end [0139] 4. connection ends [0140] a. first connection end [0141] b. second connection end [0142] 5. ball [0143] a. spindle attachment opening [0144] b. indexer aperture [0145] c. ball body [0146] 6. through-going opening in ball [0147] 7. valve seat [0148] 8. valve spindle [0149] a. valve spindle opening in valve housing [0150] 9. welding seam on valve housing [0151] a. welding spot [0152] 10. welding tool [0153] a. welding laser/welding torch [0154] b. mirror [0155] 11. arm/shaft of welding tool [0156] a. radial bore for indexer [0157] 12. indexer [0158] a. bore (conical) [0159] b. sliding surface [0160] c. connecting bore [0161] d. arrow indicating radial in/out movement of indexer [0162] 13. indexer actuator [0163] a. sliding surface, wedged surface [0164] b. arrow indicating axial in/out movement of indexer actuator [0165] 14. duct or bore in arm/shaft [0166] 15. turret [0167] 16. bushing/holder for valve housing part [0168] 17. bearing [0169] 18. rotation axis/longitudinal axis [0170] a. Rotating direction [0171] 19. camera position