WO2019145770A1

WO2019145770A1 - Valve assembly with a sealing group

Info

Publication number: WO2019145770A1
Application number: PCT/IB2018/059768
Authority: WO
Inventors: Giuseppe Francesco BULLA
Original assignee: Nuova Dlm Valvo Srl
Current assignee: Nuova Dlm Valvo Srl
Priority date: 2017-12-19
Filing date: 2018-12-07
Publication date: 2019-08-01
Anticipated expiration: 2020-06-19
Also published as: EP3728911A1

Abstract

A valve assembly comprising a conduit which extends in length concentrically to a main axis, wherein said valve assembly includes: wherein the at least one sealing group has a shape substantially complementary to a sealing housing comprising: - a support body axially movable parallel to the main axis; - a main sealing member housed on the support body engaging the shutter group in a main sealing zone which is radially distant from the main axis by a main distance; - a secondary sealing member housed on the support body sealably engaging the secondary body in a first secondary sealing zone radially distant from the main axis by a first secondary distance and sealably engaging the sealing housing in a second secondary sealing zone radially distant from the main axis by a second secondary distance, wherein the first secondary distance is less than the main distance which is less than the second secondary distance; - an abutment ring.

Description

DESCRIPTION

"VALVE ASSEMBLY WITH A SEALING GROUP"

[0001] The present invention concerns a valve assembly. In particular, the valve assembly object of the present invention is specifically applied in a system for the circulation of pressurized fluid. That is to say, the valve assembly that is object of the present invention is suitable to be fluidically connected to the conduits of said system to control the passage of the gaseous fluid inside the system or, conversely, to control the blocking thereof .

[0002] According to a preferred embodiment, said pressurized fluid is of the aeriform type, such as gases or hydrocarbons. According to a variant embodiment, said pressurized fluid is of the liquid type, such as liquid nitrogen .

[0003] Specifically, the valve assembly covered by the present invention is of the spherical shutter type, in which, according to the angular arrangement of the shutter, the flow of the pressurized fluid is permitted or prevented. In particular, the valve assembly is equipped with at least one sealing group that sealingly engages the shutter.

[0004] In the state of the art, a variety of valve assembly solutions with such features are known. In particular, valve assembly embodiments are known that differ from each other according to how they operate in the case wherein the shutter is placed in a blocking position and there is a critical situation or emergency in which, following a change in the state of the pressurized fluid, for example as a result of an increase in the temperature thereof, there is an increase in its pressure in the chamber wherein the spherical shutter is housed. Such situation is particularly risky and undesirable as there is a risk of an explosion of the valve group.

[0005] The state-of-the-art solutions differ according to the behavior of said sealing groups in the event that such a critical situation occurs.

[0006] Firstly, there are known solutions wherein the sealing group sustains the action of the overpressure in the shutter chamber and allows a venting of the pressurized fluid in the system conduit (such sealing groups are also known as "single piston effect") .

[0007] Secondly, solutions are known wherein the sealing group discharges the action of the overpressure and prevents the venting of the pressurized fluid in the conduit (such sealing groups are also known as "double piston effect") .

[0008] A typical problem of the aforesaid "double piston effect" solutions is that they have particularly complex sealing groups that require a complex design, a high number of components and the need to perform complex and numerous machining operations, especially on the valve body .

[0009] The need is therefore particularly felt to have a valve assembly in which is obtained the "double piston effect" behavior that is however simplified compared to the solutions belonging to the state of the art.

[0010] The purpose of the present invention is thus to provide a valve assembly according to the aforesaid requirement .

[0011] Such object is achieved by means of a valve assembly according to claim 1. The dependent claims show preferred variant embodiments and further features leading to a series of new advantages.

[0012] The object of the present invention will now be described in detail, with the help of the accompanying figures, wherein:

- figure 1 illustrates a perspective view of the valve assembly object of the present invention, according to a preferred embodiment;

- figure 2 shows a perspective view with some separate parts of the valve assembly shown in figure 1;

- figure 2a represents an enlarged view of some of the details shown in figure 2; - figure 3 shows a side view of the valve assembly as shown in figure 2;

figures 4 and 4 show two side views partially in cross-section of the valve assembly referred to in the preceding claims, wherein the shutter group comprised therein is, respectively, in an open configuration and a closed configuration;

figures 5a and 5b represent the enlargement of the portion indicated in figure 4 at A in two different operative configurations relative to the shutter group in the closed position: in figure 5a the sealing group comprised in the valve assembly is arranged in a normal operative configuration; in figure 5b the sealing group comprised in the valve assembly is arranged in an emergency operative configuration;

- figure 6 shows an enlarged cross-sectional view of the valve assembly, and in particular of the sealing group, according to a preferred embodiment, according to which a greasing conduit of the sealing group is visible.

[0013] With reference to the aforesaid figures, a valve assembly of a system for the circulation of pressurized fluid is indicated collectively at reference number 1. That is, the valve assembly 1 is suitable to be fluidically connected with special conduits of said system for the circulation of pressurized fluid. [0014] In particular, the valve assembly 1 defines inside of it a conduit 100 through which the fluid flows under pressure. Preferably, the conduit 100 is suitable to receive pressurized fluid from an inlet system conduit and for transferring pressurized fluid to an outlet system conduit.

[0015] In particular, said conduit 100 extends in length concentrically to a main axis X-X.

[0016] According to the present invention, the valve assembly 1 comprises a shutter group 2 suitable to permit or prevent the passage of the fluid. In particular, the shutter group 2 is of the on/off type. The shutter group 2 is in effect available following specific rotation about a valve axis Z-Z in an open and a closed position. With a single linear conduit 100, the two positions entail a 90° rotation of the shutter comprised in the shutter group 2.

[0017] According to the present invention, said shutter group 2 comprises a spherical shutter 20. The spherical shutter 20 comprises a spherical surface 21.

[0018] In addition, the spherical shutter 20 comprises a through hole 200 substantially equal in diameter to the conduit 100.

[0019] However, it should be noted that the present invention is not limited exclusively to embodiments with a one-way spherical shutter 20 (i.e. with a single through hole 200), but is also extended to embodiments with a multi-way spherical shutter 20 i.e. with multiple through holes; in these latter embodiments the main axis X-X coincides with the axis passing through the center of the spherical shutter orthogonal to the axis of rotation Z-Z .

[0020] According to a preferred embodiment, moreover, the shutter group 2 comprises control members 25 operatively connected with the spherical shutter 20, which may be actuated manually and/or mechanically to rotate the spherical shutter 20. In addition, said shutter group 20 also comprises support and centering means suitable to keep the spherical shutter 20 in the axial position.

[0021] According to the present invention, the valve assembly 1 also comprises at least one sealing group 3, sealingly engaging the spherical outer surface 21 of the shutter group 2. Preferably, said sealing group 3 develops substantially annularly about the main axis X-X. Said sealing group 3 is described in detail in the following .

[0022] According to the present invention, in effect, the valve assembly 1 comprises a valve body 5 comprising a shutter chamber 500 in which the shutter 20 is housed.

[0023] In particular, due to the valve body 5, the valve assembly 1 is fluidically engageable to the system for the circulation of pressurized fluid.

[0024] According to a preferred embodiment, the valve body 5 comprises respective flange ends 55 adapted to allow the valve assembly 1 to be blocked at respective conduits of the system for the circulation of pressurized fluid. Preferably, said flange ends 55 are engageable by means of flanged screw/bolt means of the same shape present on the system conduits.

[0025] In addition, according to a first preferred embodiment, the valve body 5 is specially designed to allow the spherical shutter 20 to be inserted into the shutter chamber 500 in the axial direction parallel to the main axis X-X. In other words, as shown in the solution in the accompanying figures, the valve body 5 comprises a plurality of components, for example three, joined together by special means ( screws/bolts ) : one central portion and two lateral portions in such a way that by disassembling at least one lateral portion the shutter group is thus insertable in the central portion.

[0026] On the other hand, according to another preferred embodiment, the valve body 5 is specially designed to allow the spherical shutter 20 to be inserted into the shutter chamber 500 in the axial direction parallel to the axis of rotation Z-Z; for example, the valve body 5 provides for an upper window through which the valve body is insertable.

[0027] According to the present invention, the valve body 5 comprises at the sides of the shutter chamber 500 respective conduit walls 51 defining respective sections of the conduit 100. In other words, the conduit walls 51 define an inlet section and an outlet section of the conduit separated from each other by the shutter chamber 500.

[0028] According to the present invention, at least one conduit wall 51 has a sealing housing 53, in which the aforementioned sealing group 3 is housed. In particular, therefore, said sealing housing 53 in turn extends annularly relative to the main axis X-X.

[0029] According to the present invention, the sealing group 3 has a shape essentially complementary to the sealing housing 53. In particular, a substantially complementary shape means that the sealing group 3, in the joining of the respective components that compose it, described hereinafter, finds complementary accommodation in the sealing housing 53.

[0030] According to the present invention, the sealing group 3 comprises an axially movable support body 30 parallel to the main axis X-X. In other words, as described below, the support body 30 is shaped to fit into the sealing housing in such a way as to be movable therein parallel to the main axis X-X .

[0031] According to a preferred embodiment, said support body 30, in longitudinal cross-section, is substantially L-shaped, presenting a transverse portion 30' substantially parallel to the axis of rotation Z-Z and a longitudinal portion 30" substantially parallel to the main axis X-X. According to the above, the sealing housing 53 is, in turn, substantially L-shaped.

[0032] According to the present invention, moreover, the sealing group 3 comprises a main sealing member 31 that sealingly engages the shutter group 2, in other words, sealingly engages the spherical surface 21 of the shutter group 2.

[0033] According to the present invention, therefore, the main sealing member 31 is housed on the support body 30, preferably in the transverse portion 30' thereof.

[0034] According to a preferred embodiment, the main sealing member 31 is made of a thermoplastic material.

[0035] According to a preferred embodiment, the main sealing member 31 has a tapered shape in the proximity of the shutter group 2. Preferably, the main sealing member 31 is shaped like a mule's back.

[0036] The main sealing member 31 engages the shutter group 2 in a main sealing zone Cx (or main contact zone) which is radially separated from the main axis X-X by a main distance Dx .

[0037] In addition, according to the present invention, the sealing group 3 also comprises a secondary sealing member 32 suitable to make a seal between the sealing body 30 and the valve body 5.

[0038] The secondary sealing member 32 is housed on the support body 30. In particular, as is widely visible in the figures shown, the secondary sealing member 32 is housed in the longitudinal portion 30" of the sealing body 30.

[0039] The secondary sealing member 32 sealingly engages the secondary body 30 in a first secondary sealing zone Cl (first secondary contact zone) which is radially separated from the main axis X-X by a first secondary distance dl .

[0040] In addition, the secondary sealing member 32 sealingly engages the sealing housing 53 in a second secondary sealing zone C2 (second secondary contact zone) , which is radially separated from the main axis X-X by a second secondary distance d2.

[0041] According to the present invention, the first secondary distance dl is less than the main distance Dx which is less than the second secondary distance d2.

[0042] In other words, the main sealing zone CX is positioned at a radial distance from the main axis X-X such that it always lies between the first secondary sealing zone Cl and the second secondary sealing zone C2. Preferably, said sealing zones have an annular extension concentric to the main axis X-X so that the first secondary sealing zone Cl is the closest to the main axis X-X, while the second secondary sealing zone C2 is the most distal so that between the two is found the main sealing zone CX .

[0043] According to the present invention, even after wear on the primary sealing member 31, the main sealing zone CX is comprised between the first secondary sealing zone Cl and the second secondary sealing zone C2.

[0044] According to the present invention, the sealing group 3 also comprises an abutment ring 35 housed on the support body 30 which is operatively connected to the secondary sealing member 32 which is axially movable relative to the support body 30.

[0045] In particular, the support body 30 is specially shaped defining with the walls of the sealing housing 53 an operative region 350 in which the secondary sealing member 32 and the abutment ring 35 are housed and operate. According to a preferred embodiment, said operative region 350 is located on the side of the support body 30 axially opposite to that facing the spherical surface 21. In other words, the operative region 350 is obtained along the longitudinal portion

30".

[0046] According to a preferred embodiment, said operative region 350 is defined in a radial space between the first secondary distance dl and the second secondary distance d2. In other words, as widely shown in the accompanying figures, said operative region 350 defines a single housing that extends parallel to the main axis X-X, at the bottom at the first secondary distance dl and at the top at a second secondary distance d2. In other words, said operative region 350 is delimited in a substantially rectangular space.

[0047] According to the present invention, and as illustrated below, the secondary sealing member 32 and the abutment ring 35 are suitable to carry out specific movements in the axial direction parallel to the main axis X-X within said operative region 350, in such a way that, at the axial ends of said region, they engage the valve body 5 or the support body 30 (as end stop) .

[0048] According to a preferred embodiment, the secondary sealing member 32 consists of a single component, for example an O-ring, having an inner radius equal to the first secondary distance dl and outer radius equal to the second secondary distance d2. [0049] According to such embodiment, the secondary sealing member 32 is interposed between the abutment ring 35 and the support body 30. Preferably, therefore, the axial movement of the abutment ring 35 is due to the axial thrust of the sealing member 32 that sustains the action of the pressure of the pressurized fluid in the shutter chamber 500.

[0050] According to a preferred variant embodiment, the secondary sealing member 32 consists of at least two distinct components, for example at least two O-rings, wherein the first component has an inner radius equal to the first secondary distance dl and the second component has an outer radius equal to the second secondary distance d2.

[0051] According to a preferred embodiment, the secondary sealing member 32 is housed on said abutment ring 35. Preferably, therefore, the axial movement of both the abutment ring 35 and the secondary sealing member 32, on action of the pressure of the pressurized fluid in combustion chambers, takes place simultaneously on both. Preferably, the plurality of O-rings comprised in the secondary sealing member 32 are housed on the abutment ring 35.

[0052] According to a preferred embodiment, the sealing group 3 comprises elastic thrust means 38 which perform an axial thrust action on the support body 30 to ensure the engagement of the main sealing member 31 with the spherical outer surface 21 under all operative conditions. Preferably, said elastic thrust means 38 engage the support body 30 in its transverse portion 30' . According to a preferred embodiment, in effect, said elastic thrust means 38 are suitable to perform a thrust action on the support body 30 in such a way as to ensure the seal especially in an operative configuration in which the pressure in the shutter chamber 500 is lower than the pressure in the conduit 100.

[0053] According to a preferred embodiment, the elastic thrust means 38 comprise a plurality of helical springs 380 having axial development substantially parallel to the main axis X-X and positioned angularly equidistant.

[0054] According to a preferred embodiment, said elastic thrust means 38 are placed between the support body 30 and the valve body 5 in such a way that between the two there is an annular gap through which the pressurized fluid, sealingly blocked by the second sealing member 32, flows. In other words, the elastic thrust means 38 are suitable to maintain the support body 3 in an axially forward position to facilitate the sealed engagement between the primary sealing device 31 and the spherical shutter 2. In other words, the elastic thrust means 38 perform an action that allows the passage of the pressurized fluid in the shutter chamber 500 to the operative region 350.

[0055] According to the present invention, it is emphasized that the sealing group 3 performs an action that guarantees the sealed engagement with the shutter 2, but at the same time, carries out an action that ensures the sealed engagement with the shutter body 5. This means that such engagements are ensured even in a critical situation where the pressure of the pressurized fluid in the shutter chamber 500 reaches values greater than the predefined threshold values. That is to say, the sealing group 3 has a behavior similar to that of the state-of- the-art solutions known as the double piston effect.

[0056] According to what is described above and according to what is shown in figures 5a and 5b, it is emphasized that figure 5a illustrates the axial position of the components of the sealing group 3 in a normal operative configuration, i.e. in an operative configuration in which the pressure value of the pressurized fluid in the conduit 100 is less than a predefined pressure value in the shutter chamber 500. Figure 5b shows, on the other hand, the axial position of the components of the sealing group 3 in an emergency operative configuration in which the pressure value in the shutter chamber 500 is greater than a predefined threshold value.

[0057] According to a preferred embodiment, said predefined threshold pressure value is equal to the value of the pressure of the fluid in the conduit multiplied by a safety coefficient, preferably equal to 1.33.

[0058] According to figure 6, it is also emphasized that the valve assembly 1 comprises a greasing system at the respective sealing group 3.

[0059] Said greasing system comprises a primary conduit 59 obtained in the valve body 5, a secondary conduit 39 obtained in the sealing body 30, in particular, in the longitudinal portion 30". Wherein the primary conduit 59 has preferential extension parallel to the valve axis Z- Z, while the secondary conduit 39 has preferential extension parallel to the main axis X-X. Preferably, the primary conduit 59 and the secondary conduit 39 are fluidically connected by means of a connecting conduit 359 comprised in the abutment ring 35. In this way, the greasing system carries lubricant both to the sealing group 3 and in particular within the sealing region 350 and in the proximity of the spherical shutter 20. In particular, due to the lubricant, in this way a thrust action is obtained parallel to the main axis X-X on both the secondary sealing member 32 and the primary sealing member 31. [0060] According to a preferred embodiment, the sealing group 3 comprised in the valve assembly 1 described above is positioned, following the direction of flow of the pressurized fluid in the conduit 100, downstream of the shutter group 2. In other words, it is positioned in the outlet section of the valve body 5 of the conduit 100.

[0061] According to a preferred embodiment, the valve assembly 1 comprises two sealing groups 3 engaging the spherical surface 21 at two opposite axial ends. According to a preferred embodiment, following the flow direction of the pressurized fluid in the conduit 100, respective sealing groups 3 are present and active both upstream and downstream of the shutter group 2. In other words, the same valve body is also specially designed to house two sealing groups 3. Therefore, preferably, the sealing group 3 is present both in the outlet section and in the inlet section of the valve body 5 of the conduit

100.

[0062] According to such variant embodiment, the valve body 50 comprises a vent element 58 adapted to vent the pressure present in the shutter chamber 500 when a predetermined threshold value is exceeded. Specifically, in effect, in the configuration wherein both sealing groups 3 are suitable to operate by maintaining the seal on the spherical shutter 20, both with the pressure in the shutter chamber 500 less than the threshold value and with the pressure value greater than the threshold value, by means of said venting element 58, the problem of overpressures is solved.

[0063] Innovatively, the valve assembly object of the present invention fully meets to the intended purpose by solving the problems referred to in the state-of-the-art solutions .

[0064] Advantageously, the valve assembly object of the present invention has a sealing group suitable to perform a double piston effect with simplified geometry.

[0065] Advantageously, the valve assembly object of the present invention has a valve body that requires, in its production, a limited number of mechanical operations.

[0066] Advantageously, the sealing housing has a simple shape, which is obtainable by two single mechanical operations in the axial direction, the first to obtain the housing zone of the transverse portion of the support body, the second to obtain the housing zone of the longitudinal portion of the support body in which the operative region is also housed.

[0067] Advantageously, the sealing housing is presented without edges, steps, protrusions along the main direction .

[0068] Advantageously, the sealing housing has such a shape as to allow the housing of a "single piston effect" sealing group, known in the state of the art according to what has been described above. In other words, advantageously, the valve assembly object of the present invention comprises a sealing group that operates according to the "double piston effect" principle but is replaceable with a known "single piston effect" sealing group without the need for further components or machining in the valve body.

[0069] Advantageously, the sealing group operates in a compact and defined space obtaining the double piston effect .

[0070] Advantageously, the sealing group has an extremely small number of components.

[0071] Advantageously, in a single operative region, special suitable components are provided and housed with the axial movement thereof to ensure the seal even in a critical condition and emergency.

[0072] Advantageously, due to the dynamic behavior of the secondary sealing member and the abutment ring described above, the sealing group comprises said elastic thrust means only as an option and ensures the sealing even at low pressure values of the pressurized fluid.

[0073] It is clear that a person skilled in the art, in order to satisfy contingent and specific needs, may make changes to the invention described above, all of which are, however, contained within the scope of protection as defined by the following claims.

Claims

1. A valve assembly (1) of a system for the circulation of a pressurized fluid comprising a conduit (100) which extends in length concentrically to a main axis (X-X) , wherein said valve assembly (1) comprises:

i) a shutter group (2) comprising a spherical shutter (20) rotatable about a valve axis (Z-Z) orthogonal to the main axis (X-X) having a spherical outer surface (21) and a through hole (200) having diameter substantially equal to the conduit (100);

ii) at least one sealing group (3) developing substantially annularly about the main axis (X-X) sealingly engaging the spherical outer surface (21) of the shutter group (2);

iii) a valve body (5) comprising a shutter chamber (500) in which the shutter (20) is housed, wherein the valve body (5) comprises, on the sides of the shutter chamber (500), respective conduit walls (51) defining the conduit (100), wherein a sealing housing (53) is formed on at least one conduit wall (51);

wherein said at least one sealing group (3) has a shape substantially complementary to the sealing housing (53) comprising :

a support body (30) axially movable parallel to the main axis (X-X) ; - a main sealing member (31) housed on the support body (30) engaging the shutter group (2) in a main sealing zone (CX) which is radially separated from the main axis (X-X) by a main distance (Dx) ;

- a secondary sealing member (32) housed on the support body (30) sealingly engaging the secondary body (30) in a first secondary sealing zone (Cl) radially separated from the main axis (X-X) by a first secondary distance (dl) and sealingly engaging the sealing housing (53) in a second secondary sealing zone (C2) radially separated from the main axis (X-X) by a second secondary distance (d2), wherein the first secondary distance (dl) is less than the main distance (Dx) which is less than the second secondary distance (d2);

- an abutment ring (35) housed on the support body (30) operatively connected to the secondary sealing member (32) axially movable with respect to the support body (30) .

2. Valve assembly (1) according to claim 1, wherein the support body (30) is specially shaped defining with the walls of the sealing housing (53) an operative region (350) in which the secondary sealing member (32) and the abutment ring (35) are housed and operate.

3. Valve assembly (1) according to claim 2, wherein said operative region (350) is formed on the side of the support body (30) axially opposite to that facing the spherical surface (21) .

4. Valve assembly (1) according to any one of the preceding claims, wherein the sealing group (3) comprises elastic thrust means (38) adapted to perform an axial thrust action on the support body (30) to ensure the engagement of the main sealing member (31) with the spherical outer surface (21) .

5. Valve assembly (1) according to claim 4, wherein said elastic thrust means (38) comprise a plurality of helical springs (380) having axial development substantially parallel to the main axis (X-X) and positioned angularly equidistant .

6. Valve assembly (1) according to any one of the preceding claims, wherein the secondary sealing member (32) consists of a single component, for example an 0- ring, having an inner radius equal to the first secondary distance (dl) and with outer radius equal to the second secondary distance (d2) .

7. Valve assembly (1) according to claim 6, wherein the secondary sealing member (32) is interposed between the abutment ring (35) and the support body (30) .

8. Valve assembly (1) according to any one of claims 1 to 5, wherein the secondary sealing member (32) consists of at least two distinct components, for example at least two O-rings, wherein the first component has an inner radius equal to the first secondary distance (dl) and the second component has an outer radius equal to the second secondary distance (d2) .

9. Valve assembly (1) according to claim 8, wherein the secondary sealing member (32) is housed on said abutment ring ( 35 ) .

10. Valve assembly (1) according to any one of the preceding claims, comprising a greasing system, comprising a primary conduit (59) in the valve body (5), a secondary conduit (39) in the sealing body (30) and a connecting conduit (359) in the abutment ring (35) suitable to place the primary conduit (59) and a secondary conduit (39) in fluid communication.

11. Valve assembly (1) according to any one of the preceding claims, comprising two sealing groups (3) engaging the spherical surface (21) at two opposite axial ends .

12. Valve assembly (1) according to claim 11, wherein the valve body (50) comprises a vent element (58) adapted to vent the pressure present in the shutter chamber (500) when a predetermined threshold value is exceeded.

13. Valve assembly (1) according to any one of the preceding claims, wherein the valve body (5) comprises respective flange ends (55) adapted to allow the valve assembly (1) to be blocked to respective conduits of the system for the circulation of pressurized fluid.

14. Valve assembly (1) according to any one of the preceding claims, wherein the valve body (5) is specially shaped to allow insertion of the spherical shutter (20) in the shutter chamber (500) in an axial direction parallel to the main axis (X-X) or is specially shaped to allow insertion of the spherical shutter (20) in the shutter chamber (500) in an axial direction parallel to the rotation axis (Z-Z) .