FR2779203A1 - TAP, IN PARTICULAR A BALL VALVE AND A SEALING DEVICE FOR SUCH A TAP - Google Patents

Abstract

A ball valve (10) includes a bonnet (18) and a removable insert assembly in which a valve ball (40) and opposed seat rings (46) are contained within a cartridge (20) of separable shells (20a, 20b). Cylindrical spring seals (48) of resilient and impervious high density graphite or silicon rubber are mounted on a reduced diameter length of each seat ring. The spring seals (48) are compressed between shoulders on the seat rings (46) and facing annular recessed surfaces in the cartridge and urge the seat rings into dynamic sealing contact with the valve ball (40). The spring seals (48) also provide static sealing at the interface of the seat rings (46) and the cartridge (20). Connecting fittings on mating surfaces of the bonnet (18) and the insert assembly enable the assembly to be completely removed from the valve body with the bonnet (18) for easy access for repair or replacement of components within the cartridge.

Description

The present invention relates to a tap, in particular a tap with

  ball valve and a sealing device for such a valve. Those skilled in the art also sometimes call this type of valve, ball valve. In general, the bushel is spherical but it can also be cylindrical or conical. The invention also applies

  well to a metal / metal contact valve than to a valve with flexible seats.

  Valves of this type have mainly industrial application. They are used for example in the oil, gas, petrochemical industry or in the energy industry: power plants

nuclear, thermal ...

  A valve of this type comprises in a known manner a body having a passage for a fluid as well as a housing intended to receive a shutter, at least one seat intended to cooperate with the shutter and possibly sealing means. The shutter has a generally spherical shape, has a cylindrical passage, circular or not, for the fluid and is pivotally mounted about an axis

  substantially perpendicular to the axis of the fluid passage.

  Depending on the conditions in which we work, in particular pressure and flow conditions, two types of valves are used,

  either a tree ball valve or a floating ball valve.

  In shafted ball valves, the shutter is mounted on

  two bearings located on either side of the passage for the fluid.

  The shutter is then perfectly maintained in its housing and has only one degree of freedom of pivoting. To get good

  tightness, the seats are supported on the shutter.

  Floating ball valves have a shutter that is guided and supported by the seats. The shutter therefore has a degree of freedom of pivoting but it can also slightly move in the axial direction of the passage of the fluid. The seats are then fixed and the shutter is pressed against the downstream seat relative to the direction of circulation of the fluid. In the case of shafted ball valves, the seats are pushed onto the shutter using, for example, springs or elastic seals. To achieve better support, it is known to have seats inclined on a flat surface in order to produce a corner. The housing inside the valve body then has two flat surfaces inclined relative to the axis of the passage of the fluid passing through the valve so as to form a corner. Sealing discs come to rest on the flat surfaces and receive the substantially spherical shutter. This device provides good support for the seats on the shutter and the body. However, to machine flat surfaces, it is

  necessary to provide a large opening in the valve body.

  This requires having a relatively large body, which implies a relatively large size and a high cost of

tap, especially of his body.

  The present invention then aims to provide a valve which has a pushing effect as described above without however having the disadvantage of requiring a large valve body. We therefore wish to make a tap with a

small footprint.

  The present invention also aims to provide a

  sealing device for a valve according to the invention.

  To this end, the valve, in particular a ball valve which it offers, comprises a valve body in which a passage is provided for a fluid as well as a housing intended to receive a substantially spherical obturator having a cylindrical passage for the fluid and mounted pivoting about an axis substantially perpendicular to

  the fluid passage axis and at least one seat for the shutter.

  According to the invention, the housing is of substantially frustoconical shape, with an axis parallel to the pivot axis of the shutter, and the shutter is mounted in a sheath of complementary shape of the

frustoconical housing.

  In this way, thanks to the frustoconical shape, a pushing effect can be achieved and it is not necessary to make a large opening in the body of the valve to make the housing receiving the shutter. The valve according to the invention can be a contact valve

  metal / metal or even a soft seat tap.

  In a preferred embodiment facilitating the mounting of the shutter, the sleeve is made in two parts. There are then for example two parts which are substantially symmetrical with respect to a joint plane perpendicular to the axis of passage of the fluid. For mounting, the shutter, or plug, can be placed in a part of the sleeve, then the second part of the sleeve is then placed on the first part, thus enclosing the plug, and the assembly, possibly fitted sealing means, is put in place in the housing

  provided for this purpose in the valve body.

  The invention is particularly suitable for a ball valve in which the shutter is mounted on two bearings located on either side of the fluid passage, that is to say a shafted ball valve. However, an assembly according to the invention with a ball valve

  floating is also possible.

  In the case of a shafted ball valve, guide bearings are advantageously mounted in the sleeve in order to provide guidance

shutter.

  In the valve according to the invention, the assembly of a

  frustoconical sheath inside a housing of complementary shape.

  It is then a question of carrying out a sealing between the sheath and the housing which

receives it.

  The present invention therefore proposes a sealing device for a frustoconical part mounted in a housing of complementary shape produced in a body, the whole being traversed perpendicularly or not to the axis of the truncated cone by a substantially circular cylindrical passage, characterized in what it includes: a bore made in the frustoconical part around the passage over a given depth, a tube placed at the bottom of the previous bore, machined frustoconically perpendicular or not to its main axis of a length less than the depth of the bore made and outside diameter corresponding to the diameter of the bore made, and a seal requiring a constant groove depth disposed

  in the opening of the bore, next to the tube.

  This device makes it possible to carry out sealing using joints of known types and is achievable without using too much means.

expensive.

  In this sealing device, the bore, the tube and the seal are located at the frustoconical part. The same device can be envisaged by placing these elements at the level of the body in which is

realized the accommodation.

  In this case, the proposed device is a sealing device for a frustoconical part mounted in a housing of complementary shape made in a body, the whole being traversed perpendicular or not to the axis of the truncated cone by a substantially circular cylindrical passage. , characterized in that it comprises: a bore produced in the body around the passage over a given depth, a tube placed at the bottom of the preceding bore, machined in a frustoconical fashion perpendicular or not to its main axis of a shorter length at the depth of the bore made and of external diameter corresponding to the diameter of the bore made, and a seal requiring a constant groove depth disposed

  in the opening of the bore, next to the tube.

  In an alternative embodiment of these sealing devices, it is also possible to provide a second tube obtained in the same way as the first tube, the outside diameter of which corresponds substantially to the diameter of the first tube and placed in the latter so as to protect and

  to maintain the seal on its inner part.

  Of course, the invention also relates to a ball valve as described above and which is provided with a device

  as described above.

  In any case, the invention will be well understood using the

  description which follows, with reference to the appended schematic drawing,

  representing by way of nonlimiting example an embodiment

  preferred valve and a sealing device according to the invention.

  Figure 1 is a perspective view of a valve according to the invention, Figure 2 is a sectional view along line 11-11 of Figure 1 on an enlarged scale, and Figure 3 is an exploded perspective view of the valve

  shown in the previous figures.

  Figure 1 shows a metal / metal contact ball valve. This valve comprises a valve body 2 and a cover 4 closing this valve body. On the left and on the right in figure 1, we notice two fixing flanges 6 intended for the fixing of the tap in

a circuit for a fluid.

  The cover 4 is fixed to the body 2 using threaded rods 8 and nuts 10. It has a third flange 12. In the center of the latter, the end 14 of a shaft projects. This end 14 has a square section. The shaft corresponding to this end 14 makes it possible to

  order the opening and closing of the tap shown in the drawing.

  This command can be manual or automatic. In the case of a manual control, a steering wheel or a handle can be mounted on the end 14. In the case of an automatic control, a motor can be mounted on the flange 12 and come to drive the shaft carrying the 'end

14 with square section.

  Figures 2 and 3 show in more detail the valve on the

figure 1.

  Figure 2 shows in particular a cylindrical passage 16 of circular section passing through the body 2 right through. The fixing flanges 6 are centered on this passage 16. A frustoconical housing 18, of axis 20 perpendicular to the axis 22 of passage 16, is produced in the valve body 2. This housing 18 is intended to receive a device allowing closing and opening of passage 16. This device is

described in more detail below.

  Figure 3 shows the different parts mounted in the housing 18. There is a shafted ball valve 24, two parts 26, 27 forming a sheath, two metal seats 28, two first tubes 30, two seals 32, two seconds tubes 34 and two

guide bearings 36.

  The bushed ball valve 24 has a shaft, which, in the assembled position of the valve 24, is parallel to the axis of the housing 18. This valve 24 further comprises a ball-shaped part crossed by a cylindrical bore 38 corresponding to the passage 16 The plug 24 can pivot around its shaft between a first position in which the bore 38 extends the passage 16 and a position in which the bore 38 is perpendicular to the passage 16. When the bore 38 is parallel to the passage 16, fluid can pass through the valve while in

  the other position the passage 16 is cut.

  The pivoting of the plug 24 is controlled by means of a control rod 40 whose end 14 projects beyond the valve body 2 and the cover 4. This control rod 40 is guided at the level of the cover 4 in a known manner . The parts making it possible to guide this rod 40 and to seal it around are shown in FIG. 3. There is in particular a lip seal 42, a bush forming a bearing 44, spacing rings 46 , elastic washers 48 and a nut 50. The connection between the control rod 40 and the shaft of the bushel bushel 24 is made using a key 52 mounted in a groove 54 made on the bushel shaft 24

  and a corresponding groove in the control rod 40.

  The shaft of the bushel bushel 24 extends on both sides of the spherical ball of this bushel. This shaft is guided by the two guide bearings 36. The latter are housed in housings made at this

  effect in the parts 26, 27 forming a sheath.

  The two parts 26, 27 forming a sheath are symmetrical with respect to a plane containing the axis of the housing 18 and perpendicular to the axis 22 of the passage 16. Each part 26, 27 has a passage extending the passage of the fluid 16. The bore 56 thus produced is in fact of a diameter greater than the diameter of passage 16. In fact, this bore receives each time also a seat 28, a first tube 30, a joint 32 and a second tube 34. The diameter of l the bore 56 corresponds to the outside diameter necessary to accommodate the seal 32. The first tube 30 is machined frustoconically perpendicular to its main axis. The radius of the truncated cone is less than the radius of the truncated cone corresponding to the housing 18. The difference of these radii makes it possible to obtain a groove of regular depth to receive the joint 32. The first tube 30 is therefore mounted in the bore 56 and the gasket 32 is mounted next to this first tube 30 in the opening corresponding to this bore

56 on the side of the valve body 2.

  On the side of the shafted bushel 24, the first tube 30 is shaped so as to be able to receive a seat 28. It is on this that the spherical part of the bushel 24 is supported. The second tube 34 is mounted inside the first tube 30 and is intended to protect and maintain the seal 32 on its inner part. The outside diameter of the second tube 34 corresponds to the inside diameter of the first tube 30 and the inside diameter of the second tube 34 corresponds to the diameter of the fluid passage 16. The second tube 34 extends from the opening of the bore 56 on the side from the valve body 2 to the seat 28 of the corresponding part 26, 27. The fact of having a housing 18 of frustoconical shape allows this housing to be machined through the opening whose size corresponds to the size of the base of the truncated cone. The opening made is therefore reduced in size. In addition, thanks to the push effect created by the conical shape,

  there is good support for the seats 28 on the ball 24.

  The tap described above therefore makes it possible to achieve a good seal and its cost price is lower than the tap of this same type,

  having a wedge effect, from the known prior art.

  In addition, such a valve has the advantage of not showing any wear at the level of the valve body which could hinder the operation of this valve. The only wear on the body that can appear is abrasion wear due to the passage of the fluid. Thus, when the tap is "worn", there is no need to change the body of this tap. It is enough to change the cartridge part which is housed in the frustoconical housing. This is a relatively easy operation. This advantage is particularly interesting for taps whose access

  is not easy, for example underwater taps.

  It goes without saying that the invention is not limited to the preferred embodiment described above by way of nonlimiting example; on the contrary, it embraces all variants within the framework of

  claims set out below.

  Thus, the invention is described with reference to a ball valve, or rotary valve, metal / metal contact but it can very well be applied to other valves, for example with conical valve or

cylindrical and with soft seats.

Claims (9)

  1. A valve, in particular a ball valve comprising a valve body (2) in which a passage (16) is provided for a fluid as well as a housing (18) intended to receive a substantially spherical obturator (24) having a passage cylindrical for the fluid and mounted pivoting about an axis (20) substantially perpendicular to the axis (22) of fluid passage and at least one seat (28) for the shutter, characterized in that the housing (18) is of substantially frustoconical shape, with an axis (20) parallel to the pivot axis of the shutter (24), and in that the shutter (24) is mounted in a   sheath (26,27) of complementary shape of the frustoconical housing (18).   2. Tap according to claim 1, characterized in that the   scabbard is made in two parts (26,27).   3. Tap according to claim 2, characterized in that the two parts are substantially symmetrical with respect to a joint plane   perpendicular to the axis (22) of passage of the fluid.   4. Tap according to one of claims 1 to 3, characterized in   that the shutter (24) is mounted on two bearings (36) located   on either side of the fluid passage (16).   5. Tap according to claim 4, characterized in that guide bearings (36) are mounted in the sleeve (26,27) so   to guide the shutter (24).   6. Sealing device for a frustoconical part (26,27) mounted in a housing (18) of complementary shape produced in a body (2), the whole being traversed perpendicular or not to the axis (20) of the trunk of cone by a substantially circular cylindrical passage (16), characterized in that it comprises: a bore (56) produced in the frustoconical part (26, 27) around the passage over a given depth, a tube (30) disposed at the bottom of the previous bore (56), machined frusto-conically perpendicular or not to its main axis of a length less than the depth of the bore made and of outside diameter corresponding to the diameter of the bore made, and a seal ( 32) requiring constant throat depth   disposed in the opening of the bore (56), next to the tube (30).   7. Sealing device for a frustoconical part (26, 27) mounted in a housing (18) of complementary shape produced in a body (2), the whole being traversed perpendicular or not to the axis (20) of the trunk of cone by a substantially cylindrical passage (16), characterized in that it comprises: a bore (56) produced in the body (2) around the passage over a given depth, a tube (30) disposed at the bottom of the bore (56) above, machined frustoconically perpendicularly or not to its main axis of a length less than the depth of the bore made and of outside diameter corresponding to the diameter of the bore made, and a seal (32) requiring a constant throat depth   disposed in the opening of the bore (56), next to the tube (30).   8. A sealing device according to claim 6 or 7, characterized in that it further comprises a second tube (34) obtained in the same manner as the first tube (30), the outside diameter of which corresponds substantially to the diameter of the first tube (30) and placed in the latter so as to protect and maintain the seal (32) on its part interior.   9. Tap according to one of claims 1 to 5, characterized in   that it is provided with a sealing device according to one of claims 6 to 8.