Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K3/00—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing
  • F16K3/02—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with flat sealing faces; Packings therefor
  • F16K3/0227—Packings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J15/00—Sealings
  • F16J15/16—Sealings between relatively-moving surfaces
  • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
  • F16J15/3204—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K3/00—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing
  • F16K3/02—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with flat sealing faces; Packings therefor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K3/00—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing
  • F16K3/30—Details
  • F16K3/314—Forms or constructions of slides; Attachment of the slide to the spindle

Definitions

• the present invention relates to the field of manufacturing of industrial gate valves.
• the present invention relates to a sealing assembly for a gate valve.
• the present invention also relates to an industrial valve comprising at least one first sealing assembly according to the present invention.
• Gate valves comprise, in general, at least one main body and at least one gate shutter, which is also known as a slab.
• the valve body defines a cavity for the passage for a fluid between an inlet section and an outlet section.
• the shutter is typically moved, preferably by means of a mechanical actuator, between a closing position, in which the shutter prevents the fluid from reaching said outlet section, and an opening position, for which the inlet section and the outlet section are communicating.
• Gate valves further comprise a sealing assembly interposed between the valve body and the shutter to achieve the fluid sealing when the shutter assumes the aforesaid opening position.
• a sealing assembly for gate valves comprises a ring-shaped sealing element made of thermoplastic material which is inserted by interference in a housing obtained in the seat.
• the purpose of such thermoplastic material element is to achieve the sealing allowing a relative movement between seat and shutter needed to open and close the valve itself at the same time.
• the use of this sealing element makes it possible to partially relieve the pressure which is applied between seat and shutter in order to avoid the metal-to-metal sealing which could cause the valve to seize.
• sealing assemblies which also envisage a sealing element made of elastomeric material arranged in a further housing of the seat facing the shutter when it assumes the closing position, in addition to a sealing element made of thermoplastic material.
• this element made of elastomeric material is OR- shaped or alternatively has a polygonal section evaluated with respect to a radial section plane.
• the sealing element made of elastomeric material is not optimal given the broader surface tolerances envisaged for the shutter and given the wear and the deformations due to misalignments between seat and shutter, which are consequent, for example, to the opening and closing maneuvers of the valve.
• a further drawback is found in the making of housings intended to accommodate the elastomeric ring.
• Such housings have a geometric shape matching that of the elastomeric ring and thus particularly complex to make, above all if the ring has a polygonal section.
• Another criticality of the sealing assemblies with two combined elements, one elastomeric and the other thermoplastic, is in the assembly operations which are particularly complex, above all in relation to the position of the element made of elastomeric material. According to the considerations illustrated above, it is a main task of the present invention to provide a sealing assembly for a gate valve which makes it possible to solve the aforesaid drawbacks.
• the object of the present invention to provide a sealing assembly for an industrial gate valve which makes it possible to obtain an excellent sealing both at low and at high pressures. It is another object of the present invention to provide a sealing assembly which allows simpler processing operations of the seat and/or of the shutter than those required by the traditional solutions. It is yet another object of the present invention to provide a sealing assembly which allows simpler assembly operations than those required by the traditional solutions. It is a not last object of the present invention to provide a sealing assembly which is reliable and easy to make at competitive costs.
• the present invention thus relates to a sealing assembly for an industrial gate valve, wherein said valve comprises at least one valve body and a shutter movable between and opening position and a closing position.
• the sealing assembly according to the invention comprises at least one seat, insertable in the valve body, which develops about a central axis defining an axial cavity for the passage of a pressurized fluid.
• Such seat defines a first front surface which faces the shutter when the seat is installed in the valve body.
• the seat also defines a main housing at its front surface.
• the sealing assembly according to the invention comprises at least one first sealing element, made of thermoplastic material, for the fluid sealing between the seat and the shutter, said first sealing element is accommodated with interference in a first portion of said main housing.
• the sealing assembly also comprises a second sealing element, made of thermoplastic material, which is accommodated within a second portion of main housing. Such second portion is delimited axially by a closed bottom surface and is comprised between a outermost surface of said main housing and the first sealing element.
• the second sealing element is accommodated with radial clearance in said second portion of said main housing to float, with respect to the seat, along a direction parallel to said central axis when the seat is installed in the valve body and when the seat is internally crossed by the pressurized fluid.
• the sealing element according to the invention further comprises anti-extrusion means configured to prevent the extraction of said second element from the second portion of said main housing during the step of opening of said valve.
• the present invention allows to obtain the sealing against the shutter by using thermoplastic material elements only.
• the use of elastomeric material elements is thus avoided and the issues found for them is overcome.
• the sealing assembly according to the invention it is possible to achieve optimal sealing at both low and high pressures, thus reducing the problems of wear and fatigue deterioration.
• the second sealing element is pushed against the surface of the seat by the fluid pressure which insinuates between the two sealing elements exploiting the radial clearance with which the second sealing element is inserted in the same second portion.
• the thrust on the second sealing element by the fluid advantageously increases and thus so does the sealing effect against the shutter.
• the pressure is reduced and consequently so is the force which thrusts the second sealing element against the shutter, thus limiting the phenomena of wear and mechanical fatigue.
• the possibility of relative movement of the second sealing element with respect to the seat, due to the fact that the second sealing element floats in the second portion of the main housing, guarantees the possible compensation of the elastic deformation of the shutter due to the fluid pressure.
• the sealing assembly according to the present invention guarantees solidity and reliability in terms of deterioration and equivalent performance of the elastomeric insert at low pressures.
• the presence of the thermoplastic sealing element further ensures a lower friction, and thus a lower valve opening force value than the solution with elastomeric seal.
• the first portion and the second portion of the main housing are axially delimited by a first wall and by a second wall, respectively.
• the distance of the first bottom surface from the front surface of the seat is greater than the distance between the second bottom surface and the front surface itself.
• the first housing portion is axially deeper than the second housing portion.
• the two sealing elements may be installed simultaneously in the main housing.
• the main housing is radially delimited between a innermost surface and a outermost surface and defines an intermediate surface which develops axially between the bottom walls.
• a portion of the first element is inserted with interference between the innermost surface and the intermediate surface.
• the innermost surface of the main housing and/or said intermediate surface define fixing teeth which intervene on the innermost surface and/or on the outermost surface of the first sealing element.
• the fixing teeth apply a blocking force which is added to that provided by the coupling with interference.
• the second sealing element comprises a outermost surface and a innermost surface evaluated in radial direction.
• Such outermost surface comprises a first portion and a second portion connected by an intermediate portion inclined in direction of said central axis.
• the outermost surface of the main housing comprises a first portion leaning on/in contact with the first portion of the outermost surface of the second element and a second portion at least partially recessed towards the central axis; such second portion comprises an abutment region facing the intermediate portion of the outermost surface of the second element.
• the intermediate portion is distanced from the abutment region and defines a first gap adapted to allow, in presence of pressurized fluid, the axial movement of the second sealing element.
• the abutment region establishes a limit stop position for the axial movement of the second sealing element in the housing. Such abutment region thus prevents the release of the second element from the second portion of the main housing.
• the anti-extrusion means are advantageously defined by the conformation assigned to the outermost surface of the second sealing element and to the outermost surface of the main housing.
• the innermost surface of the second sealing element comprises a first portion and a second portion connected by an intermediate portion inclined with respect to the central axis in a sense opposite with respect to the intermediate portion of the outermost surface of the second element itself.
• the outermost position surface of the first sealing element comprises at least one first portion adjacent and facing the first portion of the innermost surface of the second element and a further portion, near said front surface of the seat, which radially emerges towards the outermost surface of the main housing; such further portion comprises an abutment region for the intermediate portion of the innermost surface of the second element.
• the intermediate portion of the innermost surface of the second element is distanced from the abutment region of said further portion defining a second space which allows, in presence of pressurized fluid, the axial movement of the second sealing element.
• this abutment region defined at the outermost surface of the first sealing element, acts as anti-extrusion means for the second sealing element. Indeed, such abutment region establishes in fact a limit stop to the movement of the second sealing element.
• grooves which develop axially from a front surface to a rear surface of the second element and which develop radially towards the outermost surface of the second element, are defined at the innermost surface of the second element.
• the grooves allow the pressurized fluid to penetrate more easily between the two sealing elements to the second bottom wall so that it applies its thrust action on the second sealing element. The presence of such grooves translates into a more rapid and fluid movement of the second sealing element.
• FIG. 1 is a section view of a gate valve comprising two sealing systems according to the present invention
• FIG. 2 is an enlargement of the detail II shown in Figure 1 ;
• FIG. 3 and 4 are different perspective views of a first possible embodiment of a sealing assembly according to the present invention.
• FIG. 5 is a first exploded view of the sealing assembly in Figure 3;
• FIG. 6 is a second exploded view of the sealing assembly in Figure 3;
• FIG. 1 shows a gate type valve 1 , comprising a sealing assembly according to the present invention.
• the valve 1 is intended to be installed on a fluid pipe and comprises a body 20 which defines a housing in which a shutter 1 0 is accommodated.
• the shutter 1 0 is movable between an opening position and a closing position, respectively, to allow the passage of a flow Q or not between an inlet section 20A and an outlet section 20B defined by the body 20.
• the valve 1 shown in Figure 1 comprises a first sealing assembly 1 01 and a second sealing assembly 1 02 according to the invention operatively to achieve the fluid sealing on opposite sides L1 , L2 of the shutter 1 0. For this reason, the first sealing assembly 1 01 and the second sealing assembly 1 02 are operatively installed respectively upstream and downstream of the shutter 1 0 with respect to a flow direction 200 defined by the body 20 of the valve 1 .
• the shutter 10 appears as a slab defining an opening 10A.
• the valve comprises a first hollow portion 1 A and the second hollow portion 1 B mutually opposite with respect to the central cavity within which the fluid moves. Means which allow the movement of the shutter 1 0 between the two operative positions (opening and closing) are accommodated in the first portion 1 A.
• the shutter 1 0 In the opening position (condition in Figure 1 ), the shutter 1 0 partially emerges in the second hollow portion 1 B.
• the two sealing assemblies 1 01 ,1 02 intervene on the respective sides L1 , L2 of the shutter 10 both in the opening position and in the closing position.
• the sealing assembly 1 01 comprises a seat 30 which is installed in the valve body 20.
• the seat 30 develops as a revolution solid around a central axis A and defines an axial cavity 6 for the passage of a pressurized fluid (liquid or gas).
• the central axis A identifies the fluid flow direction through the seat 30 when it is inserted in the valve body 20 and the valve 1 is open.
• the direction of flow (arrow Q in Figure 3) is obviously established by the conditions of the installation in which the valve is inserted.
• the seat 30 defines a front surface 30A which faces the shutter 1 0 when the seat 30 is installed in the valve body 20.
• the front surface 30A mainly develops on a cross plane 1 04 which is substantially orthogonal to the central axis A defined above.
• the seat 30 defines an accommodating main housing 35 at said front surface 30A.
• the main housing 35 faces towards the shutter 1 0 when the seat 30 is installed in the valve body 20.
• the main housing 35 comprises a first housing portion 35A, delimited axially (i.e. in a direction parallel to the central axis A) by a first closed bottom wall 51 .
• the main housing 35 also comprises a second seat portion 35B, communicating with said first housing portion 35A, which is axially delimited by a second bottom wall 52.
• the first bottom wall 51 and the second bottom wall 52 develop on respective planes 51 0,520, preferably orthogonal to the central axis A.
• the distance L1 between the first bottom wall 51 and the front surface 30A of the seat 30 is greater than the distance L2 between the second wall 52 and the second front surface 30A (see Figure 4).
• the two distances L1 , L2 are evaluated according to a direction parallel to the central axis A.
• the first housing portion 35A is axially deeper than the second housing portion 35B.
• the main housing 35 is radially delimited (i.e. according to a direction orthogonal to the central axis A) between a innermost surface 61 and a outermost surface 62.
• the expressions “innermost' and “outermost' refer to the position of the surfaces 61 ,62 with respect to the central axis A. Consequently, the innermost surface 61 will be the surface of the main housing 35 closer to the central axis A, while the outermost surface 62 will be the one more distant from the same central axis A.
• the first housing portion 35A is entirely delimited between said innermost surface 61 of said main housing 35 and an intermediate surface 63 which develops axially between the two bottom walls 51 ,52.
• the two surfaces 61 ,63 which radially delimit the first housing portion 35A are cylindrical and coaxial to the central axis A.
• the sealing assembly 101 comprises at least one first sealing element 3, made of thermoplastic material, configured as a ring and inserted with interference in said first housing portion 35A.
• the two surfaces 61 ,63 which radially delimit the first housing portion 35A defining a plurality of fixing teeth 77 (indicated in Figure 6) which act on the outermost surfaces of the first sealing element 3.
• the first element 3 is inserted in the first housing position 35 so that a first front portion 3A thereof is inserted with interference in the annular gap defined between the innermost surface 61 and the intermediate surface 63.
• the fixing teeth 77 if present, can perfect the connection, increasing the action of the coupling with interference.
• the sealing assembly 101 also comprises a second sealing element 4 accommodated in said second housing portion 35B between said first element 3 and said outermost surface 62 of said main housing 35.
• the sealing element 4 is accommodated with radial clearance R within the second housing 35B so as to float, with respect to the seat 30, in the seat itself. The latter is thus radially delimited by the outermost surface 32 of the first ring 3 (stably inserted in the first housing portion 35A) and by the outermost surface 62 of the main housing 35.
• the word “floating' means the possibility conferred to the second sealing element 4 to move along a direction parallel to the central axis A when the seat 30 is installed in the valve body 20 and internally crossed by the pressurized fluid at the same time.
• the expression “radial clearance” means a condition in which the area of the section of the second element 4 evaluated on the plane orthogonal to the central axis A is smaller than the area, evaluated on the same plane, of the second housing portion 35B (area comprised between the outermost surface 62 of the main housing 35 and the outermost surface 32 of the first sealing element 3).
• the cross section area of the second housing portion 35B is from 1 % to 5% greater than the cross section area of the second element 4.
• the cross section area of said second housing portion 35B is from 1 % to 3% greater than the cross section area of the second sealing element 4.
• the sealing element 1 01 according to the invention further comprises anti- extrusion means to prevent the extrusion of the second element 4 from the second housing portion 35B during the step of opening of the valve 1 .
• the anti-extrusion means have the function of establishing a limit stop position to the axial movement of the second sealing element 4.
• the second sealing element 4 is ring-shaped defined by a outermost surface 42, more distant from the central axis A, and a innermost surface 41 , closer to the central axis A.
• the second element 4 further defines a front surface 4A, intended to contact the shutter 1 0 to achieve the sealing, and a rear surface 4B facing the second bottom wall 52.
• the outermost surface 42 comprises a first portion 421 , intended to remain within the second housing portion 35B and a second portion 422 intended to come out, at least partially, from the same second housing portion 35B.
• the second portion 422 has a radial extension, evaluated with respect to the central axis A, smaller than that of the first portion 421 .
• the two portions 421 ,422 are connected by an intermediate portion 423 tapered towards the central axis A.
• the two portions 421 ,422 are cylindrical and develop coaxially about the central axis A.
• the outermost surface 62 of the main housing 35 comprises a first surface portion 621 , preferably cylindrical, which is backed/in contact with the first portion 421 of the outermost surface 42 of the second sealing element 4.
• the outermost surface 62 of the main housing 35 also comprises a second surface portion 622 at least partially recessed towards the central axis A.
• Such second portion 622 preferably defined near the front surface 30A of the seat 30, comprises an abutment region 623 faced and distanced from the intermediate portion 423 of the outermost surface 42 of the second element 4.
• the word "distanced” indicates a condition, evaluated in absence of pressurized fluid, so that a gap (indicated by G1 ), which allows, in presence of the pressurized fluid, the axial (floating) movement of the sealing element 4 towards the shutter 1 0, is defined between the abutment region 623 and the intermediate portion 423. More precisely, following such axial movement, the front surface 4A of the second element 4 comes into contact with the shutter 1 0. Such movement stops when the intermediate portion 423 of the second sealing element 4 abuts against the abutment region 623 defined by the second portion 622.
• the anti-extrusion means are thus defined by the conformation of the outermost surface 42 of the second element 4 and of the conformation of the outermost surface 62 and of the main housing 35.
• the abutment region 623 is tapered/inclined so as to be parallel to the intermediate portion 423 of the outermost surface 42 of the second ring 4.
• the abutment region 623 and the intermediate portion 423 have the same tapering, i.e. a same inclination angle a, evaluated according to a direction parallel to the central axis A (see Figure 7).
• Such angle a is preferably comprised in a range between 1 0 and 90 °, preferably between 1 0 ° and 90 °. If the angle a is equal to 90 °, then the portions 423,623 would be defined on planes substantially orthogonal to the central axis A.
• the second element 4 has a innermost surface 41 comprising a first portion 41 1 and a second portion 41 2.
• such portions 41 1 ,41 2 are cylindrical and coaxial with the central axis A.
• the second portion 41 2 has a radial extension (diameter) greater than that of the first portion 41 1 .
• the two portions are connected by an intermediate portion 41 3 inclined/tapered towards the central axis A.
• the first portion 41 1 and the second portion 41 2 are substantially opposite to the first cylindrical portion 421 and the second portion 422 of the outermost surface 42.
• the intermediate portion 41 3 of the innermost surface 41 is opposite to the intermediate portion 423 of the outermost surface 42.
• the intermediate portion 41 3 of the innermost surface 41 has an inclination, with respect to the central axis A, opposite to the inclination of the intermediate portion 423 of the outermost surface 42.
• the inclination of the intermediate portion 413 indicated above is indicated by the angle ⁇ .
• Such angle ⁇ is comprised in the range of values between 0 ° and 90 °.
• the innermost surface 41 of the second element 4 is cylindrical, as shown in the embodiment in Figures 9 and 1 0 discussed below.
• the angle ⁇ assumes a value equal and opposite to the angle a.
• the distance H2 between the two portions 41 1 ,41 2 of the innermost surface 41 substantially corresponds to the distance H1 between the two portions 421 ,422 of the outermost surface 422 of the second element 42.
• the second element 4 comprises a rear part, comprised between the two mutually opposite portions 41 1 and 421 and a front part, comprised between the two mutually opposite portions 41 2 and 422. The rear part is thus tapered towards the front part through an intermediate part comprised between the two intermediate portions 413 and 423.
• the outermost surface 32 of the first sealing element 3 comprises a first substantially cylindrical portion 321 , in which a first stretch is in contact with said intermediate cylindrical surface 63 and in which a second stretch is adjacent and facing the innermost surface 41 of the second sealing element 4.
• the outermost surface 32 of the first element 3 also comprises a second portion 322, vicinal to the front surface 30A, which emerges radially towards the outermost surface 62 of the main housing 35 defining an abutment region 323 for the intermediate portion 41 3 of the innermost surface 41 of the second element 4.
• a second gap, indicated by G2 which also allows, in presence of pressurized fluid, the axial (floating) movement of the sealing element towards the shutter 1 0, is defined between these two parts 41 3-323 .
• the area of the gap G1 evaluated on a radial reference plane containing the central axis A, is substantially equivalent to the area of the gap G2, evaluated on the same radial reference plane.
• the abutment region 323 is tapered/inclined so as to be parallel to the intermediate portion 41 3 of the innermost surface 31 of the second ring 4.
• the abutment region 323 and the intermediate portion 41 3 have the same inclination angle ⁇ .
• grooves 8 which develop axially from the front surface 4A to the rear surface 4B of the element itself, are defined preferably at the innermost surface 41 of the second element 4. Such grooves 8 develop instead radially in direction of the outermost surface 42 of the second element 4.
• the grooves 8 are defined at preferably equal angular intervals about the central axis A.
• the purpose of the grooves 8 is to promote the penetration of the pressurized fluid between the two sealing elements 3,4 up to the second wall 52 which delimits the second seat portion 35B in which the second element 4 is accommodated. In this manner, the thrust on the rear surface 4B of the second element 4 is ensured.
• FIGs 7 and 8 better illustrate the operating principle of the sealing assembly according to the invention, particularly but not exclusively in the embodiment shown in Figures 3-6.
• the seat 30 is thrust towards the shutter 1 0 by the elastic means 9 (shown in Figure 2) which act between the seat itself and the valve body 20.
• the first sealing element 3 is thrust against the shutter 1 0.
• the action taken by the first element 3 may be sufficient to achieve the sealing of the fluid.
• the fluid overcomes the barrier constituted by the first element 3 and insinuates in the axial grooves 8 or in all cases in the interface reason between the two elements 3,4 (condition in Figure 8) to reach the second wall 52 of the first housing 35.
• the fluid applies a thrust SP against the rear surface 4B of the second element 4 after which it moves (floats) in axial sense. Following such movement, the front surface 4A of the second element 4 is pushed against the shutter 10 thus achieving the sealing also at high pressures.
• the thrust SP on the first element 10 correspondingly increases as the fluid pressure increases, and consequently so does the sealing offered by the system.
• the fluid pressure radially presses the second element 4 against the outermost surface 62 of the main housing 35, thus preventing the fluid from exiting on top. So, unlike the traditional solutions, also at high pressures, the sealing between seat 30 and shutter 1 0 is achieved only by means of elements of thermoplastic material 3,4.
• Figures 9, 1 0, 1 1 and 1 2 are views related to possible alternative embodiments with respect to that shown in aforesaid figures 3, 5 and 6.
• the innermost surface 41 of the second ring 4 and the outermost surface 32 of the first ring 3 have a substantially cylindrical shape for their entire length.
• the innermost surface 41 of the second ring 4 does not envisage axial grooves.
• the floating movement of the second element 4 is in all cases guaranteed by the radial clearance R (deliberately accentuated in Figure 9) by which the element itself is inserted in the second position 35B.
• Such radial clearance in all cases allows the pressurized fluid to penetrate to the second wall 52 of the main housing 35 to achieve the axial thrust on the second element 4 according to the principle indicated above.
• the embodiment shown in Figure 1 0 differs from that shown in Figure 9 only because the second element 4 comprises instead a plurality of grooves 8 which develop from the front surface 4A to the rear surface 4B to implement the function described above for the embodiment shown in the Figures from 3 to 6.
• the grooves 8 allow a more fluid and uniform axial movement of the second element 4.
• the second element 4 defines a circular housing 44 at its outermost surface 42 and more precisely at its first substantially circular position 421 .
• a further sealing ring 7 is accommodated, preferably but not exclusively made of elastomeric material.
• Such ring 7 defines in substance a supplementary sealing between the outermost surface 42 of the second element 4 and the outermost surface 62 of the main housing 35.
• the ring 7 prevents the pressurized fluid from going round the second element 4 over the region in which its front surface 4A comes into contact with the shutter 1 0.
• the circular housing 44 is defined by a groove which develops inside the second element 4, in intermediate position between the rear surface 4B and the front surface 4A and even more preferably between the rear surface 4B and the second portion 422 of the outermost surface 42 defined above.
• the circular housing 44 could be defined by a shoulder obtained at the rear surface 4B of the second sealing element 4.
• the circular seat 44 is open towards the second bottom wall 52.
• the sealing ring 7 is comprised between said second wall 52 and a surface 47 of the second sealing element 4 which is recessed with respect to the rear surface 4B of the second element 4 itself.
• the sealing ring 7 is an O-ring made precisely of elastomeric material.
• a U-shape ring seal or a lip-seal (simple or double) type seal made of thermoplastic material may be inserted in the circular housing 44.
• Figure 1 2 shows an embodiment of the sealing assembly according to the invention which differs from those in Figures from 3 to 6 only in that said second element does not envisage any sealing ring interposed between the outermost surface 42 of the second element 4 and the outermost surface 62 of the main housing 35. Therefore, the use of the ring 7 must be considered as a preferred, but not exclusive, technical solution.
• the seat 30 defines a further housing 36 facing the shutter 1 0.
• This further housing 36 is ring-shaped and develops mainly in axial sense being delimited by a outermost cylindrical surface 72 and a innermost cylindrical surface 71 .
• Said further housing 36 is delimited in axial sense by a closed bottom part 73.
• a scraper element 80 also ring-shaped is accommodated in said further housing 36.
• the function of the scraper element 80 is to preserve the first element 3 and/or the second element 4 from any impurities present in the fluid and to prevent the possible contact between the seat 30 and the shutter 1 0 at high pressures.
• the scraper ring 80 contributes to the sealing action implemented by two sealing elements 3,4.
• the scraper ring 80 is accommodated with interference in said further housing 36.
• the cylindrical surfaces 71 ,72 of the further housing 36 may also comprise toothings 77A (see figure 6) configured to apply a blocking on the two cylindrical surfaces 71 ,72 which delimit the scraper ring in radial sense 80.
• said further housing 36 is defined in a innermost radial position with respect to the main housing 35.
• said further housing 36 is defined in a radial position between the central axis A and the main housing 36. This arrangement is visible in the embodiment shown in Figures from 3 to 6.
• said further housing 36 may be defined in a outermost radial position, i.e. such that the main housing 35 is defined in a radial position comprised between the central axis A and said further housing 36.
• first element 3 and/or the second element 4 may be made of PTFE (with various composites), PA, PEEK, POM, PCTFE and similar thermoplastic polymers in order to achieve the fluid pressure sealing between seat 30 and shutter 1 0.
• the sealing elements 3 and 4 are preferably made of PEEK.
• the scraper ring 80 shown above may also be made of one of the thermoplastic materials indicated above, preferably of PEEK.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Sealing Devices (AREA)

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• 2017
  • 2017-04-07 WO PCT/IB2017/052016 patent/WO2018185529A1/en active Application Filing
  • 2017-09-12 RU RU2017131779A patent/RU2737930C2/ru active
• 2018
  • 2018-04-04 CN CN201810301644.2A patent/CN108692045B/zh active Active

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