WO2022185352A1

WO2022185352A1 - Ball valve with two working positions

Info

Publication number: WO2022185352A1
Application number: PCT/IT2022/050037
Authority: WO
Inventors: Gian Matteo SABEDDU
Original assignee: A.V.V. Added Value For Valves S.R.L.
Priority date: 2021-03-02
Filing date: 2022-02-28
Publication date: 2022-09-09
Also published as: IT202100004658A1; EP4302001A1

Abstract

The present invention relates to the field of fluid transport in high or low pressure circuits and concerns, in particular, a ball valve with two working positions, particularly of the on/off type, adapted to connect two pipes and to allow, or shut off, the flow of a fluid therethrough, comprising: • - a valve body; • - a spherical plug (2) arranged in the valve body so as to be able to rotate inside it; • - control means for said spherical plug; • - a first (3) and a second (4) annular seat placed inside said valve body, adapted to house said plug and comprising a reference surface facing said plug; • - fluid-tight means interposed between said spherical plug and said first and second annular seat, of the type comprising a first (5) and a second (6) annular gasket projecting from the reference surface of each seat; • - coacting means of cam type between said spherical plug and each of said seats, adapted to allow contact between said first and second gasket and said spherical plug only in the two working positions with ball valve (1) completely open or closed and to determine the movement of said first and second seat away from said spherical plug in the intermediate positions. The present invention also relates to the field of spare parts.

Description

BALL VALVE WITH TWO WORKING POSITIONS

Technical field

The present invention relates to the field of fluid transport in high or low pressure circuits and concerns, in particular, a ball valve with two working positions, particularly of the on/off type, adapted to connect two pipes and to allow, or shut off, the flow of a fluid therethrough. The present invention also relates to the field of spare parts for these ball valves.

Background art

Ball valves are the most common and widely used type of device for shutting off a flow in hydraulic pipes.

Ball valves essentially comprise:

- a valve body, adapted to couple with the pipes on which the valve is to be fitted;

- a spherical plug, provided with a cylindrical through opening coaxial to the flow, housed in the valve body so as to be able to rotate inside it;

- two lateral sealing seats placed inside said valve body and adapted to house said spherical plug;

- fluid-tight means interposed between said spherical plug and each of said seats;

- a lateral locking ring nut, adapted to clamp on said valve body when the spherical plug in inserted inside it;

- a stem, or control rod, adapted to coact directly with said spherical plug;

- a lever, or more generally operating means.

By means of a rotation through 90°, the spherical plug shuts off the fluid creating the two working positions of the valve, i.e., the conditions of interrupting the flow of the fluid (off) or of complete opening of the valve (on).

The plug is inserted inside the valve body, and is compressed against the two seats that have the task of guaranteeing seal (i.e., the absence of leakages) when the valve, in the closed position, must allow total shut off of the fluid (or in any case with residual leakage values within the values dictated by the technical standards of reference).

Currently, fluid-tight means are mainly produced with annular gaskets made of elastomeric or thermoplastic materials, chosen according to the specific application or to the working conditions of the ball valve.

To guarantee perfect seal, said annular gaskets protrude with respect to a reference surface facing said spherical plug (or contact plane). The most conventional solutions, for applications with standard operating pressure and temperature values and irrelevant chemical inertias, provide for the use of elastomeric gaskets, such as rubber O- rings, highly suitable from a mechanical point of view, as they are capable of withstanding substantial elastic deformation and of returning to their original size when at rest once again. Alternatively, for applications in which greater temperature resistance ranges are required, thermoplastic gaskets are used.

Finally, in the case of more extreme applications, for example for values in circuits with fluids that are highly aggressive from a chemical point of view, it is preferable not to use gaskets, but to ensure seal with a direct metal-to-metal contact between the spherical plug and the seats of the valve, after hardening treatment of the contact surface.

In use, frictions are created between the various internal members of the valve.

In particular, the friction that develops between the spherical plug and the lateral sealing seats contributes to increasing the torque required for rotation of the spherical plug (opening and closing operation). As one of the most significant functional parameters of a good ball valve is a low operating torque in the different operating conditions, it is clear how when designing a high performance ball valve, it is fundamental to minimize internal frictions due to rubbing between the parts. Moreover, the friction that is generated between spherical plug and seats speeds up the wear process of the gaskets, which in fact tend to become easily worn due to mutually rubbing with the metal parts they come into contact with.

Naturally, wear through friction involves not only the gaskets, but also the metal parts, in particular the seats, which inconveniently require to be replaced with a certain frequency. The costs of these operations can be high, above all when the manufacturing materials of the valve are of high quality or the valves are complex and of large size. Even more inconveniently, in the case of maintenance operations on existing valves, not all manufacturers guarantee spare parts: in substance, being unable to use reverse engineering it may even be necessary to replace the whole valve, once again with lengthy maintenance times and high costs Presentation of the invention

The object of the invention is to overcome these limits, producing a ball valve with two working positions for high or low pressure fluid circuits which is durable, not subject to wear and thus capable of guaranteeing maximum seal at all times, easy to operate and which does not require high handling forces.

A further object of the invention is to produce a ball valve with low production and maintenance costs.

Yet another object of the invention is to provide spare kits for existing valves, reducing the number of components to be replaced and thus optimizing costs.

The objects are achieved with a ball valve with two working positions comprising:

- a valve body;

- a spherical plug arranged in the valve body so as to be able to rotate inside it;

- control means for said spherical plug; - a first and a second annular seat placed inside said valve body, adapted to house said spherical plug and comprising a reference surface facing said plug;

- fluid-tight means interposed between said spherical plug and said first and second annular seat, of the type comprising a first and a second annular gasket projecting from the reference surface of each seat, characterized in that it comprises coacting means of cam type between said spherical plug and each of said seats, adapted to allow contact between said first and second gasket and said spherical plug only in the two working positions with ball valve completely open or closed and to determine the movement of said first and second seat away from said spherical plug in the intermediate positions.

According to a first aspect of the invention, said coacting means of cam type comprise a first and a second cam profile produced on said spherical plug, parallel to each other and arranged symmetrically with respect to an equatorial plane of said spherical plug, and adapted to coact with contact reading means present on said first and second seat.

In particular, said first and second cam profile comprise a lobed profile, and preferably said lobed profile comprises four lobes protruding beyond an outer surface of said spherical plug.

According to a further aspect of the invention, said coacting means of cam type comprise blocks, projecting from the reference surface of the seat, but not beyond said annular gaskets, adapted to act as contact reading means of said first and second cam profile.

According to a possible variant of embodiment, said coacting means of cam type comprise, for each seat, a first and a second sliding block adapted to coact with sliding contact respectively with said first and second cam profile.

In an alternative variant, said coacting means of cam type comprise, for each seat, a first and a second rotating block adapted to coact with rotating contact respectively with said first and second cam profile.

Preferably, said rotating blocks are of the cylinder or ball bearing type.

Alternatively, said blocks comprise a thermoplastic, elastomeric, metallic or composite material, having substantially the same properties of chemical resistance as said annular gaskets.

According to a further aspect of the invention, said first and second seat each comprise two slots, diametrically opposite each other, each adapted to house one of said blocks.

The subject matter of the invention is also a spare part kit for a ball valve with two working positions, where said ball valve comprises:

- a valve body;

- control means for said spherical plug;

- a first and a second annular seat placed inside said valve body, adapted to house said spherical plug and comprising a reference surface facing said plug;

- fluid-tight means interposed between said spherical plug and said first and second annular seat, of the type comprising a first and a second annular gasket projecting from the reference surface of each seat, characterized in that said spare part kit comprises:

- a shaped spherical plug comprising a first and a second cam profile produced thereon, parallel to each other and arranged symmetrically with respect to an equatorial plane thereof; - a first and a second shaped seat each comprising two slots, diametrically opposite each other, and blocks, housed in said slots, adapted to act as reading means of said first and second cam profile.

The advantages of the invention derive from the temporary movement of the seats away from the spherical plug during its rotation in the opening and closing operations of the valve caused by the coaction between output and input of the cam mechanism.

The main advantage of the invention with respect to conventional ball valves is a considerable decrease in the torque required for rotation of the spherical plug and for the opening and closing operations of the valve in the passage to its working positions.

Having eliminated rubbing between seats and spherical plug during the opening and closing steps of the valve, the torque is reduced and the force required to operate the valve is limited.

Moreover, as there is no longer any rubbing between the components, the annular gaskets, made of soft material, are also preserved and the valve, due to less wear, has an increased life cycle.

In designing and sizing the gaskets only front seal of static type is considered; it is no longer necessary to consider dynamic seal in the presence of friction, as there is no longer any rubbing during rotation of the plug. For dynamic seal small contact bands were necessary between the gasket of the seat and the spherical plug to minimize frictions and specific pressures. Moreover, hard materials were necessary to increase the wear resistance, or materials with good sliding properties to improve friction. Instead, the solution in question for static seal only, favours wide contact areas between the gaskets of the seats and the spherical plug to improve the sealing and the use of softer materials to give the valve a better seal.

Even more advantageously, as the plug no longer rubs on the seat, precise roundness grinding of the whole plug is no longer necessary, minimal machining of the spherical plug, for example simple milling to produce the lobed cam profiles, being sufficient.

Moreover, without rubbing there is no longer the risk of the gaskets being expelled from their seats.

The ball valve is in general simpler to produce and consequently less expensive.

All the seats, even those of existing valves, can be adapted and modified to contain the blocks according to the invention which will coact with the specific spherical plug.

Alternatively, thanks to the spare part kit, it is possible to modify an existing valve, supplying spherical plug provided with cam profiles and shaped seats provided with dedicated blocks in once piece.

The fact that the cam profiles are produced directly from the spherical plug and are not added components to be mounted in the valve further facilitates the operations to replace and modify existing valves.

Inside the valve, the overall dimensions of the spherical plug with cam profiles produced is the same as a conventional spherical plug, so that, in the case of replacement and adaptation, perfect compatibility is guaranteed between mechanical parts.

Moreover, a free space remains available between plug and valve body which can advantageously be occupied by specific supports for the ball adapted to support the plug from above and below.

Simplifying the valve to the extent that it can be adapted to the solution according to the invention merely by means of a spare part kit considerably reduces costs.

In any case, thanks to the solution in question, it is possible to produce a movement of the seats away from the plug without having to change materials, take action on the original manufacturer’s general design, or resize the components.

Brief description of the drawings

These and other advantages will be more evident below, in the description of preferred embodiments of the invention provided by way of non-limiting example, and with aid of the figures wherein:

Fig. 1 represents, in an axonometric view sectioned along a vertical plane, a ball valve according to the invention in a working position thereof;

Figs. 2 and 3 represent, respectively in an axonometric view and in a front view, the spherical plug of the valve of Fig. 1 according to the invention;

Figs. 4a, 4b and 4c represent, respectively in a partial front plan view, in an axonometric view and in a section along a vertical detail plane, a seat of the valve of Fig. 1 according to a first possible variant of the invention;

Figs. 5a, 5b and 5c represent, respectively in a partial front plan view, in an axonometric view and in a section along a vertical detail plane, a seat of the valve of Fig. 1 according to a second possible variant of the invention;

Figs. 6a, 6b and 6c represent, respectively in a partial front plan view, in an axonometric view and in a section along a vertical detail plane, a seat of the valve di Fig. 1 according to a third possible variant of the invention;

Figs. 7 and 8 represent, in a section along a vertical plane, a detail of a ball valve according to the invention respectively in the two working positions;

Fig. 9 represents, in longitudinal section according to a vertical plane, a preferred variant of a ball valve according to the invention.

Detailed description of preferred embodiments of the invention

With reference to Fig. 1 there is shown a ball valve 1 with two working positions for high or low pressure circuits, substantially comprising: - a valve body, adapted to couple with a first pipe upstream and a second pipe downstream (not illustrated) on which the valve 1 is to be fitted;

- a spherical plug 2 provided with a cylindrical through opening coaxial to the flow of fluid, housed in the valve body so as to be able to rotate inside it, controlled by an actuator means (not illustrated);

- a first 3 and a second 4 annular sealing seat placed inside said valve body, coaxial to said pipes, and adapted to house said spherical plug 2.

Said first 3 and second 4 annular seat each comprise a reference surface facing said plug 2.

Said ball valve 1 comprises a first 5 and a second 6 annular gasket interposed between said first 3 and said second 4 seat and said spherical plug 2. Said first 5 and second 6 gasket act as fluid-tight means to prevent leakages of fluid from and toward the inside of the valve 1.

Said first 5 and second 6 gasket are housed in specific annular slots 17 produced on each seat 3, 4 and partly protrude, projecting from the reference surface of the related seat. This protrusion must be sufficient to offset the deformation through compression sustained by the gasket subjected to the pressure of the plug 2.

In detail, said gaskets 5, 6 are made of thermoplastic material and have a trapezoidal section. The inclined plane of the gasket 5, 6 contains the contact point with said spherical plug 2.

Said ball valve 1 comprises coacting means of cam type between said seats 3, 4 and said spherical plug 2 adapted to allow contact between said first 5 and second 6 gasket and said spherical plug 2 only in the working positions with the ball valve 1 completely open or closed and to determine the movement of said first 3 and second 4 seat away from said spherical plug 2 in the intermediate positions, so as to avoid continuous rubbing of the spherical plug 2 against seats 3, 4 and gaskets 5, 6 and thus reduce frictions.

Said coacting means of cam type comprise a first 7 and a second 8 cam profile (input) produced on said spherical plug 2, parallel to each other and arranged symmetrically with respect to an equatorial plane p of said spherical plug 2, and adapted to coact with contact reading means (output) produced on said first 3 and second 4 seat.

In particular, said first 7 and second 8 cam profile are produced directly by machining a single piece of metallic material that forms the spherical plug 2 and belong to it; they are not fitted to the spherical plug as foreign bodies but derive from suitable milling operations on the surface thereof.

Said coacting means of cam type further comprise blocks 9, 10, 11 , 12, 13, 14, protruding beyond the reference surface of the seat 3, 4, but not beyond said gaskets 5, 6, adapted to act as reading means of said first 7 and second 8 cam profile.

Said first 7 and second 8 cam profile are each located on a cap 2’, 2” of said plug 2 facing the outside of said ball valve 1 , above the circumference of contact of said spherical plug 2 with said gaskets 5, 6. In Figs. 2 and 3, in which only the spherical plug 2 is illustrated, said first 7 and second 8 cam profile are clearly visible, arranged along two parallels thereof.

In Fig. 2 said first cam profile 7 is clearly visible.

Said first cam profile 7 comprises a lobed profile, and in particular comprises four lobes T protruding beyond the outer surface of said spherical plug 2. The contour of said cam profile 7 substantially creates four cusps and four depressions: when the reading means of the seats 3, 4 are located in said depressions, the plug 2 and seats 3, 4 are in contact, the gaskets 5, 6 are pressed against the plug 2 and said ball valve 1 is in the valve open or closed configuration (Fig. 7), while when the reading means of said seats 3, 4 are located on said cusps, the plug 2 and seats 3, 4 are moved away from each other, the gaskets 5, 6 are free and said ball valve 1 is in an intermediate position (Fig. 8).

It is clear that said second cam profile 8, although not illustrated in detail, has the same features, the same configuration with four lobes 8’ and the same operating mode.

With particular reference to the details of Figs. 4a, 4b, 4c, 5a, 5b, 5c, 6a, 6b, 6c, these illustrate seats 3, 4 according to possible variants of embodiment of the invention.

In the description below, although reference will be made to said first seat 3 it is clear that all the features presented may also be valid symmetrically also for said second seat 4.

Said first seat 3 comprises two slots 15, 16, placed at the ends of a diameter thereof and adapted to house a first 9, 11 , 12 and a second 10, 13, 14 block adapted to coact respectively with said first 7 and second 8 cam profile.

With particular reference to the variant of Figs. 4a, 4b and 4c, said coacting means of cam type comprise a first 9 and a second 10 sliding block, adapted to coact with sliding contact with said cam profiles 7, 8.

Said first 9 and second 10 sliding block are produced by means of inserts retained in said slots 15, 16.

The portion of said sliding blocks 9, 10 that protrudes externally to said slots 15, 16 beyond the reference surface of the seat 3 comprises an arcuate profile (Fig. 4b) adapted to facilitate sliding with the corresponding cam profile 7, 8.

Said sliding blocks 9, 10 are made of thermoplastic material, such as PTFE or PEEK, or of the same material as the sealing gaskets of the valve, or with the metallic material of which the seats are made.

With particular reference to the variant of Figs. 5a, 5be 5c, said coacting means of cam type comprise a first and a second rotating block, adapted to coact with rotating contact with said cam profiles 7, 8.

Each rotating block comprises a cylinder 11 , 13 whose longitudinal axis is arranged radially with respect to the seat 3.

Said cylinder 11, 13 is rotatably associated with said seat 3 by means of a pin 18 so as to rotate around it.

In the detail of Fig. 5c, the slot 15 that houses said cylinder 11 is a recess that concerns the outer edge of said seat 3 and said seat 3 comprises a constraining plate 19 adapted to retain said cylinder 11 in position. Said constraining plate 19 is also passed through by said pin 18 and is associated with said seat 3 by means of screws 20.

Being cylinder shaped, said block 11 also has an arcuate profile in its portion protruding beyond the reference surface of the seat 3, adapted to facilitate sliding of the cam profile 7.

Said cylinders 11 , 13 are made of thermoplastic material, such as PTFE or PEEK, or of the same material as the sealing gaskets of the valve.

With particular reference to the variant of Figs. 6a, 6b and 6c, said coacting means of cam type comprise a first and a second rotating block of the type comprising a ball bearing 12, 14, adapted to coact with rotating contact with said cam profiles 7, 8.

Said ball bearings 12, 14 are retained in said slots 15, 16 by means of a pin 21 which forms the rotation axis thereof.

Also in this case, the outer ring and the inner ring of said ball bearings 12, 14 are made of thermoplastic material, such as PTFE or PEEK, or of the same material as the sealing gaskets of the valve.

In general, all the blocks 9, 10, 11 , 12, 13, 14 described and illustrated, in addition to being made of thermoplastic material, can also be made of elastomeric material, such as vulcanized rubber, or of metallic material, for example the same material as the seats, thus of steel, or of composite material, having substantially the same properties of chemical resistance as said gaskets.

All the seats 3, 4, even those of the existing valves 1, can be adapted and modified to contain said block reading means according to the invention.

Alternatively, thanks to the spare part kit, it is possible to modify the existing valve 1 , supplying the modified spherical plug 2 with cam profiles 7, 8 and seats 3, 4 shaped with the respective dedicated blocks 9, 10, 11 , 12, 13, 14 in one piece.

With particular reference to Fig. 9, all the components of the ball valve 1 are illustrated, in particular a stem 22, i.e., the operating means of the spherical plug 2, and two ball supports, i.e., an upper support 23 and a lower support 24, adapted to house, guide and maintain the spherical plug 2 aligned and in position.

Said ball supports 23, 24 are arranged over and under the cam profiles 7, 8 produced on the spherical plug 2 and do not interfere with it.

The operation of the invention is described below with reference to Figs. 7 and 8 showing details relating to two working positions of the valve 1 , respectively a fixed closing or opening position and a transition and movement position.

When the valve 1 is in the completely closed or open position, the seal is allowed thanks to the contact between the spherical plug 2 and the annular gaskets 5, 6 housed in the seats 3, 4 located inside the valve body.

Operatively, when said ball valve 1 is in the completely open or closed configuration (Fig. 7) of the valve, the contact reading means of the seats 3, 4, i.e., the blocks 11 , 13, are located in the depressions of the cam profiles 7, 8; the plug 2 and the seats 3, 4 are in contact; the gaskets 5, 6 are pressed against the plug 2.

On the contrary, when the valve 1 is in the transition and movement position (Fig. 8), it is important for the gaskets 5, 6 to be free and not to rub against the plug 2 with friction; the seats 3, 4 must remain at a distance from said plug 2. This condition occurs when the reading means of said seats 3, 4, i.e., the blocks 11 , 13, are on the cusps of the cam profiles 7, 8.

Claims

1 ) A ball valve (1 ) with two working positions comprising:

- a valve body;

- a spherical plug (2) housed in the valve body so as to be able to rotate inside it;

- control means for said spherical plug (2);

- a first (3) and a second (4) annular seat placed inside said valve body, adapted to house said spherical plug (2) and comprising a reference surface facing said plug;

- fluid-tight means interposed between said spherical plug (2) and said first (3) and second (4) annular seat, of the type comprising a first (5) and a second (6) annular gasket projecting from the reference surface of each seat (3, 4), characterized in that it comprises coacting means of cam type between said spherical plug (2) and each of said seats (3, 4), adapted to allow contact between said first (5) and second (6) gasket and said spherical plug (2) only in the two working positions with ball valve (1) completely open or closed and to determine the movement of said first (3) and second (4) seat away from said spherical plug (2) in the intermediate positions.

2) The ball valve (1) with two working positions according to claim 1, characterized in that said coacting means of cam type comprise a first (7) and a second (8) cam profile produced on said spherical plug (2), parallel to each other and arranged symmetrically with respect to an equatorial plane (TT) of said spherical plug (2), and adapted to coact with contact reading means present on said first (3) and second (4) seat.

3) The ball valve (1) with two working positions according to claim 2, characterized in that said first (7) and second (8) cam profile comprise a lobed profile.

4) The ball valve (1) with two working positions according to claim 3, characterized in that said lobed profile comprises four lobes (7’, 8’) protruding beyond an outer surface of said spherical plug (2).

5) The ball valve (1) with two working positions according to claim 2, characterized in that said coacting means of cam type comprise blocks (9, 10, 11 , 12, 13, 14), projecting from the reference surface of the seat (3, 4), but not beyond said annular gaskets (5,

6), adapted to act as contact reading means of said first (7) and second (8) cam profile.

6) The ball valve (1) with two working positions according to claim 5, characterized in that said coacting means of cam type comprise, for each seat 3, 4), a first (9) and a second (10) sliding block adapted to coact with sliding contact respectively with said first (7) and second (8) cam profile.

7) The ball valve (1) with two working positions according to claim 5, characterized in that said coacting means of cam type comprise, for each seat (3, 4), a first (11 , 12) and a second (13, 14) rotating block adapted to coact with rotating contact respectively with said first (7) and second (8) cam profile.

8) The ball valve (1) with two working positions according to claim 7, characterized in that said rotating blocks are of cylinder (11 , 13) or ball bearing (12, 14) type.

9) The ball valve (1) with two working positions according to claim 5, characterized in that said blocks (9, 10, 11 , 12, 13, 14) comprise a thermoplastic, elastomeric, metal or composite material, substantially having the same properties of chemical resistance as said annular gaskets (6, 7).

10) The ball valve (1) with two working positions according to claim 5, characterized in that said first (3) and second (4) seat each comprise two slots (15, 16), diametrically opposite each other, each adapted to house one of said blocks (9, 10, 11 , 12, 13, 14).

11) A spare part kit for a ball valve (1) with two working positions, where said ball valve (1) comprises:

- a valve body;

- a spherical plug (2) arranged in the valve body so as to be able to rotate inside it;

- control means for said spherical plug (2);

- a first (3) and a second (4) annular seat placed inside said valve body, adapted to house said spherical plug (2) and comprising a reference surface;

- fluid-tight means interposed between said spherical plug (2) and said first (3) and second (4) annular seat, of the type comprising a first (5) and a second (6) annular gasket projecting from the reference surface of each seat (3, 4), characterized in that said spare part kit comprises: - a shaped spherical plug (2) comprising a first (7) and a second (8) cam profile produced thereon, parallel to each other and arranged symmetrically with respect to an equatorial plane (TT) thereof;

- a first (3) and a second (4) shaped seat each comprising two slots (15, 16), diametrically opposite each other, and blocks (9, 10, 11 , 12, 13, 14), housed in said slots (15, 16), adapted to act as reading means of said first (7) and second (8) cam profile.