Butterfly valve with adaptable sealing housing

Abstract

A valve comprising a body having an inner annular face defining a passage in an axial direction, a butterfly, mounted to rotate inside the body from an open position, clearing the passage, to a closed position, closing it, having an outer face that is opposite the inner face of the body in the closed position and whose concavity faces inwards, the inner face of the body and the outer face of the butterfly converge towards each other in the axial direction to define a housing, a sealing gasket being received in the housing and free to move entirely within the housing in all directions, the shape of the longitudinal section of the inner face of the body being curved when its concavity faces the butterfly or straight when inclined towards the butterfly. Figure for the abbreviation: Fig. 2

Description

Title of the invention: Butterfly valve with adaptable sealing housing

[0001] The present invention relates to butterfly valves. A butterfly valve ensures upstream / downstream sealing in a circuit. It consists of a body, integral with the piping, defining, by means of an annular internal seat, an interior forming a passage having an axial direction, and a butterfly mounted to rotate within the body from an open position uncovering the passage to a closed position sealing it.

[0002] Since these elements are rigid, an intermediate seal, generally more flexible, is usually added to ensure proper surface matching and a sufficient level of sealing. In a butterfly valve, the seal is ensured in the median plane of the butterfly in the closed position.

[0003] EP3642515 is a known example of a valve comprising a free seal that is not statically fixed to either the valve body or the butterfly, nor is it mounted with complementary shapes. This type of seal operates with two dynamic contact areas, one on the body and one on the butterfly, and in the open position, it assumes the most suitable position without being stressed or constrained. In the closed position, it is constrained only by the fluid and its pressure and thus does not undergo any stress due to a fixed attachment; it positions itself in the most suitable position.

[0004] However, when the geometries of the body and the seat are not perfectly defined or realized or when the body and the seat are not properly assembled, the geometric defects of realization and assembly confronted with a joint that is too rigid lead to a loss of contact of the joint with the body and therefore a leak.

[0005] The present invention aims to overcome the drawbacks of the prior art by means of a tap comprising:

[0006] - a body having an inner annular face delimiting a passage having a axial direction,

[0007] - a butterfly mounted inside the body rotating relative to a shaft of maneuver, from an open position, clearing the passage, to a closed position, blocking it, having an outer face that is opposite the inner face of the body in the closed position and which turns its concavity inwards.

[0008] - the inner face of the body and the outer face of the butterfly converging towards the other in the axial direction to define a housing, the housing and the operating shaft not being at intersection,

[0009] - a sealing gasket received in the housing and free to move as a whole in housing in all directions,

[0010] characterized in that the inner face of the body is curved by turning its concavity towards the butterfly or is flat by being inclined with respect to the axial direction (A), thus generating a hollow truncated cone oriented towards the center of the tap.

[0011] Preferably, the longitudinal section of the inner face of the body is curved by turning its concavity towards the butterfly.

[0012] Contact between the seal and the body is best maintained when the longitudinal section The inner face of the body is a circular arc of an ellipse. This is the mathematically perfect shape. A circular arc, easier to produce, is also an alternative. A straight line, generating a truncated hollow cone whose imaginary apex points towards the center of the tap, is a compromise that may be suitable for a less sophisticated soft-joint tap.

[0013] By way of example, a preferred embodiment of the invention is now described by reference to the drawings, in which:

[0014] [Fig. 1] is a perspective view with partial removal of a tap according to the invention,

[0015] [Fig. 2] is a longitudinal cross-sectional view of part of a tap, the butterfly of which has been unfortunately mounted off-center in the body of the tap according to the invention and,

[0016] [Fig.3] is a diagram illustrating variants of the invention.

[0017] The valve shown in the figures comprises a body 1 whose interior, delimited by an annular inner face 2, forms a passage for the fluid flowing in an axial direction A from upstream (left in [Fig. 2]) to downstream (right in [Fig. 2]). A normally centered butterfly 3 (in [Fig. 1]) is mounted to rotate under the action of an operating shaft 8 within the body from an open position, clearing the passage, to a closed position, sealing it. The butterfly 3 has an outer peripheral face 4 which is opposite the inner face 2 of the body in the closed position. The inner face 2 of the body and the outer face 4 of the butterfly converge towards each other in the axial direction downstream to define a housing 5 in which an annular sealing gasket 6 is received, held in position by a flange 7 or in a groove of the body 1. The operating shaft 8 does not pass through the housing 5.The seal 6 is free to move fully within the housing in all directions. A shaft / body seal is also provided to prevent leaks to the outside when the tap is in the open or closed position.

[0018] The longitudinal section (i.e., in a plane parallel to axis A, like that of [Fig. 2]) of the inner face 2 of the body is a segment of an ellipse with its concavity facing the butterfly 3, and the longitudinal section of the outer face 4 of the butterfly is an arc of a circle with its concavity facing inwards. The ellipse of the body has a major axis to minor axis ratio between 1.1 and 1.5.

[0019] According to another embodiment of the invention, the longitudinal section of the inner face 2 of the body is an arc of a circle turning its concavity towards the butterfly 3.

[0020] According to another embodiment of the invention, the longitudinal section of the inner face 2 of the body is an inclined segment at an angle between 5° and 30° with respect to the axial direction A.

Claims

Demands

1. A valve comprising a body (1) having an inner annular face (2) defining a passage having an axial direction (A), a butterfly (3), mounted inside the body (1), rotating relative to an operating shaft (8), from an open position, clearing the passage, to a closed position, closing it, having an outer face (4) which is opposite the inner face (2) of the body in the closed position and which turns its concavity inwards, the inner face (2) of the body and the outer face (4) of the butterfly converging towards each other in the axial direction (A) to define a housing (5), the housing (5) and the operating shaft (8) not intersecting, a sealing gasket (6) received in the housing (5) and free to move as a whole within the housing (5) in all directions,characterized in that the inner face (2) of the body is curved by turning its concavity towards the butterfly (3) or is flat by being inclined with respect to the axial direction.

2. Tap according to claim 1, characterized in that the shape of the longitudinal section of the inner face (2) of the body is an arc of ellipse.

3. Tap according to claim 1, characterized in that the shape of the longitudinal section of the inner face (2) of the body is an arc of a circle.

4. Tap according to claim 1, characterized in that the shape of the longitudinal section of the inner face (2) of the body is rectilinear inclined at an angle between 5° and 25° with respect to the axial direction (A).

5. Valve according to any one of the preceding claims, characterized in that the butterfly (3) is mounted centered inside the body (1).

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