PLUG VALVE

Description

[0001] The present invention relates to the field of ball valve mechanisms and more particularly to sealing mechanisms for ball valves. Examples of ball valves are known from documents US 2021 / 033200 A1, US 2019 / 346064 A1 and CN 106 286 900 B.

[0002] Ball valves are based on a substantially cylindrical structural construction positioned across an inlet and an outlet. This construction involves a cylindrical part with a circular cross-section traversed by a conduit for the circulation of a fluid, this cylindrical part being inserted into a housing of substantially complementary shape inside which the cylindrical part is mounted to pivot axially. The pivoting is then arranged to align the through conduit of the cylindrical part with the inlet and outlet ports of the valve.

[0003] Valves are designed to allow or block the flow of a fluid through a circuit. Also, for a valve to operate optimally by efficiently managing the flow of the fluid passing through it, it is essential that the valve operates perfectly tightly, both to prevent any passage when it is in the closed position and to prevent any loss of flow when it is in the open position. In ball valves, the cylindrical shape and curved surface of the ball provide additional constraints in managing the seal between the surface of the ball and each of the valve's inlet and outlet ports. Indeed, perfect surface complementarity between the ball and the ports is complex to achieve, particularly due to the clearances that may exist between the surfaces of the valve's internal parts.

[0004] To address this problem, one solution is to position a circular seal, for example an O-ring, at each of the internal openings of the valve orifices, so that these seals are positioned in compression between the surface of the plug and the peripheral surface of an internal opening of an orifice. However, such a solution quickly reaches its limits. Indeed, the frictional movement of the curved surface of the plug against the sealing gasket leads to wear of the seal or even its deformation at the level of its junction surface with the plug, so that the seal is likely to show a loss of the quality of its sealing.

[0005] The present invention aims to overcome these drawbacks by proposing a ball valve which is capable of ensuring the maintenance of effective sealing in its operation over time, while having a design which is easy to implement.

[0006] The invention thus relates to a ball valve characterized in that the valve comprises at least: a valve body comprising an interior volume associated with at least two communication orifices with respective conduits, a cylindrical plug of circular section, the plug comprising at least one through circuit between at least two orifices carried by the peripheral surface of the plug, at least two orifices of the plug being arranged on the peripheral surface to be able to be positioned simultaneously opposite respective communication orifices of the valve body, an intermediate element comprising at least two through orifices between two opposite surfaces, interior and exterior, the through orifices being opposite respective communication orifices of the valve body, the exterior surface of the intermediate element being configured to be positioned opposite the interior volume of the valve body,the inner surface bearing at least one relief surrounding a through orifice being configured so that the top of the relief forms around the orifice at least one continuous contact surface bearing against the peripheral surface of the valve, a sealing joint positioned in compression at the level of an orifice between the intermediate element and the valve body.

[0007] The invention will be better understood from the following description, which relates to different preferred embodiments, given as non-limiting examples, and explained with reference to the appended schematic drawings, which: [ Fig. 1 ] illustrates a schematic representation in section of an example of a ball valve according to the invention, [ Fig. 2 ] illustrates a schematic representation of a first example of an intermediate element for a ball valve according to the invention, [ Fig. 3 ] illustrates a schematic representation of a second example of an intermediate element for a ball valve according to the invention, [ Fig. 4 ] illustrates a schematic representation of a third example of an intermediate element for a ball valve according to the invention, [ Fig. 5 ] illustrates a schematic representation of an example of a sealing gasket for a ball valve according to the invention, [ Fig. 6 ] illustrates a schematic representation of different parts of an example of a cylindrical plug for a plug valve according to the invention, [ Fig. 7 ] illustrates a schematic representation of an example of a cylindrical plug for a plug valve according to the invention.

[0008] The invention relates to a ball valve characterized in that the valve comprises at least: a valve body 1 comprising an interior volume 11 associated with at least two orifices 121, 122 for communication with respective conduits 13, a cylindrical plug 2 of circular section, the plug 2 comprising at least one circuit 21 passing between at least two orifices 211, 212 carried by the peripheral surface 221 of the plug 2, at least two orifices 211, 212 of the plug 2 being arranged on the peripheral surface 221 to be able to be positioned simultaneously opposite respective communication orifices 121, 122 of the valve body 1, an intermediate element 3 comprising at least two through orifices 311, 321 between two opposite surfaces, interior 32 and exterior 31, the through orifices 311, 321 being opposite orifices 121, 122 of respective communication of the valve body 1, the outer surface 31 of the intermediate element 3 being configured to be positioned opposite the inner volume 11 of the valve body 1,the inner surface 32 carrying at least one relief 33 surrounding a through orifice 321 being configured so that the top of the relief 33 forms around the orifice 321 at least one continuous contact surface 331 bearing against the peripheral surface 221 of the valve 2, a seal 4 positioned in compression at the level of an orifice between the intermediate element 3 and the valve body 1.,

[0009] The ball valve according to the invention provides a sealed connection between the ball 2 and the valve body 1 which rests, on the one hand, on a frictional connection of the contact surface 331 of the intermediate element 3 against the peripheral surface 221 of the ball 2 and, on the other hand, on an elastic connection made by the seal 4 between the intermediate element 3 and the valve body 1. The ball valve according to the invention is thus able to take advantage of the elastic properties of the seal 4 without the latter supporting direct contact with the friction against the peripheral surface 221 of the ball 2. The frictional connection of a contact surface 331 of the intermediate element 3 against the peripheral surface 221 of the ball 2 thus involves contact between two rigid surfaces, so that no risk of deformation is to be expected during operation of the ball valve of the invention.The seal between an orifice 121, 122 of the plug 2 and one of the communication orifices 121, 122 of the valve body 1 is thus achieved, on the one hand, by the seal 4 which forms a ring around the alignment of the respective through orifices between the outer face 31 of the intermediate element 3 and the valve body 1 and, on the other hand, by the continuity of the contact surface 331 bearing against the peripheral surface 221 of the plug 2. A contact surface 331 of the intermediate element 3 is thus arranged so as to form a ring around one of the orifices 211, 212 carried by the peripheral surface 221 of the plug 2, so as to seal the assembly formed by the internal volumes of the orifice 311, 321 of the intermediate element 3 and of the orifice 211, 212 of the bushel 2 in relation to the other volumes and spaces likely to exist between the intermediate element 3 and the bushel 2.

[0010] In the context of the valve of the invention, the intermediate element 3 is mounted inside the valve body 1 to be locked in rotation with the latter, so that the intermediate element 3 is fixed relative to the plug 2 arranged to pivot axially inside the valve body 1. Furthermore, once in position inside the valve body 12, this intermediate element 3 is also locked in translation with the valve body 1. As a preferred example, this blocking of the intermediate element 3 in the valve body 1 involves three-dimensional shapes carried by the outer surface 31 which are substantially complementary to those of the inner surface of the valve body 12 located at the level of at least one of the orifices 121, 122. The blocking in position of the intermediate element 3 inside the valve body 1 also involves a force exerted by the valve 2 against the inner surface 32 of the intermediate element 3.This blocking of the intermediate element 3 is thus carried out by compression of this intermediate element 3 between, on the one hand, the seal 4 which creates a deformable elastic junction with the interior of the valve body 1 and, on the other hand, the plug 2. The seal 4 creates an elastic structure in the thickness of this compression to eliminate any play which might exist between the different parts of the valve and in particular in the pinching of the intermediate element 3 by the plug 2 and the valve body 1.

[0011] It should be noted that, in the context of the valve of the invention, the valve body 1 is made of at least two parts which, when assembled together, form a shell inside which the different elements of the valve are housed. According to a first construction example, the two parts of the valve body 1 are made in the form of two substantially similar halves of the valve body 1. Each of these halves of the valve body 1 comprises one or more housings specifically configured to receive one or more of the different elements positioned inside the valve. These different housings integrated into each of the halves of the valve body 1 are also arranged to cooperate with each other to define the different interior volumes when the two halves of the valve body 1 are joined together.According to a second construction example, the two parts of the valve body 1 are made so that a first part makes a housing inside which each of the different elements of the valve, if not the majority of these elements, is inserted. The second part then makes a partitioning structure of the housing formed by the first part to block the different constituent elements of the valve there.

[0012] According to an example corresponding to a construction variant of the invention, the valve comprises an intermediate element 3 structurally made of one or more parts cooperating with each other and configured to produce an arrangement which surrounds the cylindrical peripheral surface 221 of the plug 2. According to this construction variant, these parts of the intermediate element 3 cooperate with each other to produce an arrangement defining a volume inside which the plug 2 is positioned and held axially in position. The intermediate element 3 carries, at its inner surface 32, one or more contact surfaces 331 which are configured to be fully in abutment against the peripheral surface 221 of the plug 2. Also, these different contact surfaces 331 of the intermediate element 3 produce support interfaces which participate in the axial positioning of the plug 2 inside the body 1 of the valve.This volume defined by the contact surfaces 331 and inside which the valve 2 is positioned, has a cylindrical shape of substantially circular section. Such a cylindrical arrangement of substantially circular section carried by the inner surfaces 32 of the intermediate elements 3 is also arranged coaxially with the pivot axis of the valve 2, so as not to disturb, on the one hand, the rotation of the valve 2 relative to the inner surface 32 of the intermediate elements 3 which define the housing of this valve 2 and, on the other hand, the positioning of the orifices 211, 212 of this valve 2 opposite through orifices 311, 321 carried by intermediate elements 3.

[0013] According to an example corresponding to a specific construction variant of the previously detailed variant, the valve comprises an intermediate element 3 made in two parts arranged so that each of the parts of the intermediate element 3 covers a respective half of the cylindrical peripheral surface 221 of the plug 2. According to this construction variant, each of the two parts of the intermediate element 3 is structurally configured to interact with the plug 2 at the level of one half of the radial circumference of the plug 2. Thus, the contact surfaces 331 carried by the same part of the intermediate element 3 interact with the same half of the surface 221 of the plug 2 relative to a plane passing through the pivot axis of the plug 2.The two parts of the intermediate element 3 thus form two halves of a shell which, in section in a plane perpendicular to the axis of the plug, surround this plug 2 while being positioned on either side of it. Depending on the arrangement of the through-orifices 311, 321 on the intermediate element 3, the distribution of the through-orifices 311, 321 between each of the parts of the intermediate element 3 means that the parts of the intermediate element 3 are capable of carrying only one, several or possibly none of the through-orifices 311, 321.

[0014] According to an example corresponding to a construction variant capable of being combined with the different variants detailed above, the top of the relief 33 of the interior surface 32 of at least one part of the intermediate element 3 defines a contact surface 331 corresponding to at least all of the points of the virtual intersection between, on the one hand, a cylinder parallel to the axis of the through orifice 311, 321 surrounded by the relief 33 and, on the other hand, a circular cylinder whose axis coincides with the axis of the plug 2 and whose radius is less than or equal to the radius of the plug 2.According to this construction variant, at the level of the contact between the peripheral surface 221 of the valve 2 and a contact surface 331 carried by the intermediate element 3, the structures of the surfaces 221, 331 which interact with each other are arranged so that the contact between them is maintained over time in the form of a substantially annular and continuous surface which surrounds the through orifice 311, 321 of the intermediate element 3 and an orifice 211, 212 of the valve 2.The production of a contact surface 331 which corresponds to the intersection between a cylinder along the axis of the orifice 311, 321 passing through the intermediate element 3 and a circular cylinder whose axis and radius are identical to those of the valve 2, makes it possible to achieve perfect complementarity of shape between the valve 2 and the intermediate element 3 so that these two elements can easily be positioned in abutment against each other inside the valve body 1 at the level of their friction surfaces. However, preferably, the contact surface 331 corresponds to the intersection between a cylinder along the axis of the orifice 311, 321 passing through the intermediate element 3 and a circular cylinder whose axis is identical to that of the valve 2, but whose radius is slightly smaller than that of the valve 2. Thus, this difference in radius corresponds to the positioning of a concave surface of lower radius against a convex surface of higher radius.The bringing into contact of these two surfaces notably involves a deformation of the contact surface 331 carried by the relief 33 of the intermediate element 3 which is compressed against the peripheral surface 221 of the plug 2. Furthermore, these surfaces bearing against each other cause the intermediate element 3 and the plug 2 to repel each other. Thus, inside the confined volume of the valve body 1, the positioning of the plug 2 against the inner surface 32 of the intermediate element 3 causes the transmission of a compressive force of the intermediate element 3 against the seal 4 and the valve body 1. This compressive force is thus amplified by the force in spacing of the intermediate element 3 relative to the plug 2 resulting from the difference in radius between the contact surface 331 of the intermediate element 3 and the peripheral surface 221 of the plug 2.

[0015] According to an example corresponding to a construction variant capable of being combined with the various variants detailed above, the outer surface 31 of at least one intermediate element 3 has a section profile complementary to the section profile of the interior volume of the valve body 1, such that the intermediate element 3 is able to be positioned by translation in the valve body 1. A valve comprising the various technical features of this construction variant and in particular when this complementarity of section profile is arranged along a length of the interior volume of the valve body 1, the intermediate element 3 is capable of being positioned in insertion by translation of the section profile of the intermediate element 3 against the section profile complementary to at least one interior surface of the valve body 1 along a length of the valve body 1.According to an example of insertion of the intermediate element 3 into the valve body 1, the intermediate element 3 is associated with the plug 2 before the assembly formed by the plug 1 and the intermediate element 3 is inserted by translation into their position inside the valve body 1. Similarly, according to a complementary example, the intermediate element 3 is inserted into the valve body 1 while being associated, on the one hand, with the plug 2 and, on the other hand, with at least one seal 4. Thus, during this insertion, the intermediate element 3 is directly positioned in compression between the seal and the plug 2 inside the valve body 1.

[0016] According to an example corresponding to a construction variant capable of being combined with the different variants previously detailed, the intermediate element 3 comprises at least one part structurally configured to comprise a main body whose shape is similar to a portion of cylindrical tube and whose concavity is complementary to a peripheral portion of a cylinder of circular section, so that the relief 33 carried by the inner surface 32 has a continuous thickness on the inner surface 32 of the intermediate element 3. According to this embodiment variant, the intermediate element 3 has an arrangement whose inner surface 32 produces a concave construction which substantially matches the convexity of the peripheral surface 221 of the plug 2 on at least a part of the plug 2.When the intermediate element 3 is made in several parts, these different parts are arranged around the plug 2 to surround it at least on one plane in section of the plug 2. The cylindrical arrangement of the intermediate element 3 makes it possible to position this intermediate element 3 in the valve body 1 by insertion along the axis of the cylinder. This positioning can also be carried out jointly with that of the plug 2 when the axes of the cylinders of these two parts are substantially parallel to each other. Concerning the contact surface 331 carried by the dedicated relief 33 of the intermediate element 3, this has an annular arrangement around at least one of the through orifices 311, 321 of the intermediate element 3. According to an exemplary embodiment, this relief 33 takes the form of one or more thickening lines of the inner surface 32.The thickness of this relief 33 is defined so as to be sufficient to maintain a spacing between the inner surface 32 of the intermediate element 3 and the peripheral surface 221 of the valve 2, so that only the contact surface 331 carried by the relief 33 rubs against the surface of the valve 2. The relief 33 thus makes it possible to prevent the entire concave inner surface 32 from rubbing against the valve 2 and therefore imposing too great a force to set the valve 2 in rotation around its axis.

[0017] According to an example corresponding to a construction variant capable of being combined with the different variants detailed above, the intermediate element 3 comprises at least one part structurally configured to comprise a substantially planar main body whose inner surface 32 comprises a portion of a cylinder oriented along an axis perpendicular to the plane of the main body and whose end forms a continuous contact surface 331 having a concavity intended to bear against the peripheral surface 221 of the plug 2. This part of the intermediate element 3 is thus arranged to be positioned opposite a communication orifice 121, 122 of the valve body 1, in a plane substantially parallel to the plane of the communication orifice 121, 122 inside the valve body 1.According to an exemplary embodiment, the substantially planar body of the intermediate element is arranged to be positioned in a housing which comprises at least one groove on the internal face of the valve body 1. The insertion of the main body of a part of the intermediate element 3 at a groove of the valve body 1 facilitates its positioning during the assembly of the different elements of the valve of the invention. The internal surface 32 of the part of the intermediate element 3 also comprises a relief 33 produced by a portion of cylinder which surrounds a through-orifice 311, 321 positioned on the part of the intermediate element 3 and the axis of the through-orifice 311, 321 of which is perpendicular to the plane of the main body of this part of the intermediate element 3.It should be noted that, when the intermediate element 3 is constructed in several parts, each of them is capable of being positioned at a respective communication orifice 121, 122 of the valve body 1 by cooperation with a respective housing at the inner face of the valve body 1. The concavities produced by the contact surfaces 311 of the inner faces of each of the parts of the intermediate element 3 are arranged to cooperate so as to define the volume at which the valve 2 is positioned to pivot axially.

[0018] According to an example corresponding to a construction variant capable of being combined with the various variants detailed above, the outer surface 31 of the intermediate element 3 comprises at least one housing 34 configured for the positioning of at least a portion of a seal 4. According to this construction example, the seal 4 is associated with the intermediate element 3 at a housing 34 which has an annular shape arranged around an orifice 311, 321 passing through the intermediate element 3. According to an example of construction, this housing 34 is produced in the form of a groove of width substantially identical to the width of the seal 4. According to an alternative example, the width of the housing 34 is slightly less than the width of the seal 4 so that the seal 4 is positioned in compression inside the housing 34 along an axis perpendicular to the groove of the housing 34.This compression of the seal 4 in the housing 34 provides a prestress which allows stiffening of the seal 4 prior to its compression within the framework of the assembly of the various constituent elements of the valve of the invention.

[0019] According to an example corresponding to a construction variant capable of being combined with the different variants detailed above, the cylindrical valve 2 comprises, on the one hand, a deep structure 23 whose peripheral surface 231 carries at least one groove producing a movement circuit 21 and, on the other hand, a surface structure 22 whose peripheral surface produces the peripheral surface 221 of the valve 2 and covers the peripheral surface 231 of the deep structure 23; the surface structure 22 comprising at least two orifices 211, 212 passing through the surface structure 22 configured to be able to be positioned simultaneously opposite respective communication orifices 121, 122 of the valve body 1.According to this construction example, the deep structure 23 of the valve 2 incorporates one or more grooves arranged on the surface 231 of this deep structure 23, or even combined with conduits through this deep structure 23. These grooves and these conduits define one or more circuits 21 connected or independent of each other for the circulation of a fluid through the valve 2. The surface structure 22 of the valve 2 creates a covering structure for the deep structure 23 of the valve 3 so that the different grooves carried by the surface 231 of the deep structure 23 are partitioned and create conduits whose interior surface is thus formed by the combination of the deep structure 23 and the surface structure 22.The surface structure 22 comprises several orifices 211, 212 which pass through the thickness of the surface structure 22 between, on the one hand, the peripheral surface 221 of the plug 22 and, on the other hand, the interior volume of a groove or a conduit of the deep structure 23. It should be noted that the surface structure 22 is capable of comprising several groups of through orifices 211, 212, such that these groups are configured so that, alternately, the through orifices 211, 212 of these groups are simultaneously positioned opposite respective communication orifices 121, 122 of the valve body 1. This configuration makes it possible to connect, through the plug 2, different communication orifices 121, 122 of the valve body 1 according to different pivoting positions of the plug 2.Furthermore, according to another example of construction, the through orifices 211, 212 of the same group are arranged to cooperate with a particular movement circuit 21 of the plug 2. Thus, groups of different through orifices 211, 212 are associated with respective movement circuits 21 of the plug 2, so that the axial pivoting of the plug 2 makes it possible to connect different communication orifices 121, 122 of the valve body 1 via through orifices 211, 212 and different movement circuits 21 of the plug 2. It should also be noted that the surface of the surface structure 22 in contact with the deep structure 23 is complementary to the peripheral surface 231 of the deep structure 23 so as to provide a sealed junction between these two structures 22, 23 of the plug 2.Likewise, the surface structure 22 is arranged around the deep structure 23, at least at the level of the grooved portion of the deep structure 23, so that these two structural parts of the valve 2 are concentric with respect to the axial pivot axis of the valve 2.

[0020] According to an example corresponding to a construction variant capable of being combined with the previously detailed variant, the surface structure 22 and the deep structure 23 of the valve 2 cooperate by means of a means 24 for guiding in translation and blocking in rotation the surface structure 22 relative to the deep structure 23. According to this exemplary embodiment, the junction between the deep structure 23 and the surface structure 22 of the valve 2 comprises a groove carried by a first of the two structures 22, 23 and arranged to cooperate with a projecting guide element carried by the second of the two structures 22, 23 of the valve 2.By way of example, this groove is arranged along an axis substantially parallel to the axis of the valve 2, so that the assembly of these two structures, deep 23 and surface 22, is carried out by axial insertion of the deep structure 23 into the surface structure 22 by sliding the projecting guide element into the corresponding groove. As an alternative example, the groove is arranged in a spiral similar to the thread of a screw. The two structures, deep 23 and surface 22, are then assembled by screwing the surface structure 22 around the deep structure 23. Once assembled by screwing, the two structures, deep 23 and surface 22, are joined in the form of an assembly blocked in translation and axial rotation, in particular when the valve 2 is positioned inside the valve body 1.

[0021] According to an example corresponding to a construction variant capable of being combined with one of the two variants detailed above, at least one intermediate element 3 and the peripheral surface 221 of the plug 1 are made of identical or different plastic materials. Indeed, in the context of the valve of the invention, the frictional junction of a contact surface 331 of the intermediate element 3 against the peripheral surface 221 of the plug 2 thus involves contact between two rigid surfaces, so that no risk of deformation is to be expected during operation of the plug valve of the invention.Also, the plastic materials that may be used in the context of the production of the intermediate element 3 and / or the peripheral surface 221 of the valve 1 are thermoplastics of the polyamide or PPS (polyphenylene sulfide) type, or EPDM or HNBR possibly coupled with a PTFE coating in order to optimize the sliding of the rigid plastic surfaces in contact with each other. Thermoplastic and thermosetting materials loaded with PTFE are also preferred. Generally speaking, the materials used must be compatible with the fluids, gases or liquids, directed through the valve of the invention so as not to react with them.

[0022] Of course, the invention is not limited to the embodiments described and / or represented in the attached drawings.

Claims

1. Plug valve comprising at least: - a valve body (1) comprising an internal volume (11) associated with at least two communication orifices (121, 122) in communication with respective conduits (13), - a cylindrical plug (2) of circular section, the plug (2) comprising at least one circuit (21) passing between at least two orifices (211, 212) in the peripheral surface (221) of the plug (2), at least two orifices (211, 212) of the plug (2) being arranged on the peripheral surface (221) to enable said orifices to be positioned simultaneously opposite respective communication orifices (121, 122) of the valve body (1), - an intermediate element (3) comprising at least two through-orifices (311, 321) between two opposing surfaces, specifically an inner surface (32) and an outer surface (31), the through-orifices (311, 321) being arranged opposite respective communication orifices (121, 122) of the valve body (1), the outer surface (31) of the intermediate element (3) being designed to be positioned opposite the internal volume (11) of the valve body (1), the inner surface (32) bearing at least one relief (33) surrounding a through-orifice (321) being designed so that the top of the relief (33) forms about the orifice (321) at least one continuous contact surface (331) bearing against the peripheral surface (221) of the plug (2), - a gasket (4) positioned in compression on an orifice between the intermediate element (3) and the valve body (1), the valve characterized in that the top of the relief (33) of the inner surface (32) of at least a part of the intermediate element (3) defines a contact surface (331) corresponding to at least all of the points of the virtual intersection between, on one hand, a cylinder parallel to the axis of the through-orifice (311, 321) surrounded by the relief (33) and, on the other hand, a circular cylinder of which the axis coincides with the axis of the plug (2) and of which the radius is less than or equal to the radius of the plug (2).

2. Plug valve according to Claim 1, characterized in that the valve comprises an intermediate element (3) structurally made of one or more parts cooperating with one another and designed to form an arrangement that surrounds the cylindrical peripheral surface (221) of the plug (2).

3. Plug valve according to Claim 2, characterized in that the valve comprises an intermediate element (3) made of two parts arranged so that each of the parts of the intermediate element (3) covers a respective half of the cylindrical peripheral surface (221) of the plug (2).

4. Plug valve according to one of the preceding claims, characterized in that the section profile of the outer surface (31) of at least one intermediate element (3) matches the section profile of the internal volume of the valve body (1), enabling the intermediate element (3) to be positioned by translation in the valve body (1).

5. Plug valve according to one of Claims 1 to 4, characterized in that the intermediate element (3) comprises at least one part structurally designed to comprise a main body having a shape similar to a cylindrical tube portion and a concavity matching a peripheral portion of a cylinder of circular section, so that the relief (33) on the inner surface (32) has a continuous thickness on the inner surface (32) of the intermediate element (3).

6. Plug valve according to one of Claims 1 to 4, characterized in that the intermediate element (3) comprises at least one part structurally designed to comprise a substantially flat main body of which the inner surface (32) comprises a portion of a cylinder oriented along an axis perpendicular to the plane of the main body and of which the end forms the continuous contact surface (331) having a concavity intended to bear against the peripheral surface (221) of the plug (2).

7. Plug valve according to one of the preceding claims, characterized in that the outer surface (31) of the intermediate element (3) comprises at least one seat (34) designed to position at least a part of a gasket (4).

8. Plug valve according to one of the preceding claims, characterized in that the cylindrical plug (2) comprises, on one hand, a deep structure (23) of which the peripheral surface (231) has at least one slot forming a displacement circuit (21) and, on the other hand, a surface structure (22) of which the peripheral surface forms the peripheral surface (221) of the plug (2) and covers the peripheral surface (231) of the deep structure (23); the surface structure (22) comprising at least two orifices (211, 212) through the surface structure (22) that are designed to be positioned simultaneously opposite respective communication orifices (121, 122) of the valve body (1).

9. Plug valve according to Claim 8, characterized in that the surface structure (22) and the deep structure (23) of the plug (2) cooperate via means (24) for guiding the translation and constraining the rotation of the surface structure (22) in relation to the deep structure (23).

10. Plug valve according to one of the preceding claims, characterized in that at least one intermediate element (3) and the peripheral surface (221) of the plug (1) are made of the same or different plastic materials.