CORROSION-RESISTANT BALL VALVE

Abstract

A corrosion-resistant ball valve (15) comprising a housing (1; 2), in which a spherical sealing member (3) provided with a passage duct is rotatably arranged and an operating spindle (4) which is detachably coupled to the sealing member (3), in which the sealing member (3) is provided with an uninterrupted corrosion-resistant coating layer (16a), in which said coating layer comprises a tubular part (16b) which surrounds at least a part of the operating spindle (4) and a method for producing such a ball valve (15).

Claims

1. Corrosion-resistant ball valve, comprising: a housing in which a spherical sealing member provided with a passage duct is rotatably arranged; and an operating spindle which is detachably coupled to the sealing member; wherein the sealing member is provided with an uninterrupted corrosion-resistant coating layer; wherein said coating layer comprises a tubular part which surrounds at least a part of the operating spindle.

2. Corrosion-resistant ball valve according to claim 1, characterized in that the sealing member and the operating spindle are mechanically coupled to each other via a detachable lock connection.

3. Corrosion-resistant ball valve according to claim 1, characterized in that said ball valve furthermore comprises a sealing element provided for the leak-proof sealing of the space between the housing and the operating spindle.

4. Corrosion-resistant ball valve according to claim 3, characterized in that the tubular part of the coating layer extends beyond the sealing element.

5. Corrosion-resistant ball valve according to claim 1, characterized in that the coating layer is configured to be dimensionally stable.

6. Corrosion-resistant ball valve according to claim 1, characterized in that the coating layer is a fluoropolymer layer.

7. Corrosion-resistant ball valve according to claim 1, characterized in that the housing comprises two housing halves.

8. Corrosion-resistant ball valve according claim 3, characterized in that the ball valve comprises a spring which is suitable for providing a constant pressure on the sealing element.

9. Method for producing a corrosion-resistant ball valve comprising: providing a housing, in which a spherical sealing member provided with a passage duct is rotatably arranged; providing an operating spindle which is detachably coupled to the sealing member, and a sealing element which is provided to seal the space between the housing and the operating spindle in a leak-proof manner; and applying an uninterrupted dimensionally stable corrosion-resistant coating layer to the sealing member and the operating spindle, after the sealing member has been coupled to the operating spindle, so that a single-part coating layer with a spherical and a tubular part is formed, in which the tubular part surrounds at least a part of the operating spindle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to further illustrate the properties of the present invention and to indicate additional advantages and particulars thereof, a more detailed description of the corrosion-resistant ball valve according to embodiments of the present invention will now be given. It should be clear that nothing in the following description may be interpreted as a limitation of the scope of protection for the present invention defined in the claims.

[0015] Reference numerals are used in this description to refer to the attached drawings, in which:

[0016] FIG. 1 is an illustration of the cross section of a ball valve according to an embodiment of the invention in which the sealing member is shown once in the open and once in the closed position;

[0017] FIG. 2 is an illustration of the sealing member and the operating spindle of the ball valve according to an embodiment of the invention in the connected position;

[0018] FIG. 3 is an illustration of the sealing member and the operating spindle of the ball valve according to an embodiment of the invention in the non-connected position;

[0019] FIG. 4 shows a cross section of the sealing member and the operating spindle in the connected position.

DETAILED DESCRIPTION OF EMBODIMENTS

[0020] The invention relates to a change in concept with regard to the conventional fluoropolymer-coated ball valves. In a two-part housing, a spherical sealing member (3) (ball) provided with a passage (duct) for liquids or gases rotates. The sealing member (3) is rotatable about its axis at right angles to the bore. By rotating the sealing member (3) through 90°, the valve (15) either moves from being open to being closed or vice versa. The housing is made of cast iron or stainless steel. In the open position, the passage of the ball (3) is positioned in the direction of flow, in the closed position at right angles to the direction of flow. The ball (3) has a metal core, such as e.g. steel, stainless steel, bronze or another material, which is provided with a corrosion-resistant fluoropolymer coating layer (16a; 16b). A mechanical lock connection, e.g. in the form of a groove, is provided in the metal core of the ball (3) into which the operating spindle (4) engages in order to be able to perform the rotation of the ball.

[0021] According to the present invention, the coating layer (16a; 16b) which is provided around the ball (3) runs uninterrupted as far as at least a part of the operating spindle (4). In this way, as is illustrated in detail on FIGS. 2 to 4, a coating layer is formed having a spherical part (16a) and a tubular (16b) part. The spherical part (16a) surrounds the spherical sealing member (3) and the tubular part (16b) surrounds a part of the operating spindle (4). The coating layer (16a; 16b) is made from a dimensionally stable material. In use, a part of the operating spindle (4) will serve as a support for the tubular part (16b) of the coating. The operating spindle (4) can still be uncoupled from the sealing member in an easy manner.

[0022] The ball/spindle combination which is provided with the coating layer (16) rotates between two annular seats (5, 6) made of plastic (e.g. PTFE). These seats (5, 6) will ensure sealing of the valve in the closed position. These seat rings (5, 6) are in turn positioned in the two housing halves (1, 2).

[0023] A spring-loaded spindle sealing (7) provides a leak-proof dynamic seal between the coating of the spindle and the coating of the housing in order to prevent leaking of internal media to the outside environment. The spindle seal (7) is also provided with a corrosion-protecting outer layer and is supported by a corrosion-free reduction ring.

[0024] The seats (5) and (6) are positioned in the fluoropolymer-coated housing halves (1, 2). Between these seats, the fluoropolymer-coated ball (3) rotates, in which a detachably inserted spindle (4) is fitted. The ball may be configured as a complete ball shape or as a C segment. The coating of the ball runs up to at least the level of the spindle sealing (7) in order to protect the spindle (4) from corrosion. The spindle sealing (7) is supported by a reduction piece (8) and pushed down by pressure ring (9). The pressure ring (9) is pressed down by a spring (10) which is surrounded by the top flange (11). The top flange also ensures the anti-blowout function, so that the spindle cannot slip out of the housing. This is mounted in the top flange (11) via mounting bush (12). O-rings (13) and (14) prevent rainwater or external media from seeping into the ball valve.

[0025] The ball valve (15) differs from the existing types by the two-part arrangement ball/spindle, as a result of which the ball is arranged in a floating manner, with mechanical lock connection of the metal core parts which are coated by a single-part fluoropolymer coating when assembled.

[0026] The ball valve (15) according to embodiments of the invention makes it possible to produce a floating ball system comprising a lock connection between the metal parts and to keep the corrosion protection as a single piece beyond the spindle.