Patent Application
20160146357
The invention relates to a valve device, in particular in the form of a ball valve, having a blocking element movably guided in a valve housing, which may be brought, via a fluid passage by means of an actuating device from a pass-through position connecting at least two connecting points to one another in the valve housing, into a blocking position which interrupts this connection, and vice versa, and having a sealing device having at least one sealing ring which, together with its central opening, comprises the fluid passage and which seals it along at least one sealing gap. The invention further relates to a use of such a valve device and a sealing device as a component or replacement part for such valve devices.
A generic valve device of this type is known from EP 2 336 614 A1. In this known solution the respective sealing ring is received as part of the sealing device in a receiving groove of a sleeve-like sliding part, wherein the sliding part, when acted upon by an energy store in the form of a corrugated spring washer assembly, abuts with a predefinable contact force the blocking element in the form of a ball body, which is actuatable by means of a ball spindle, and which is guided for axial displacement along valve housing sections forming a guide while delimiting the sealing gap. The sleeve-like sliding part is provided twofold and is assigned to the respective connection point of the valve housing disposed on opposite sides of the blocking element.
In the known solution, the respective sealing ring is formed from a closed O-ring made of elastomer material, which, while pretensioned in the respectively assignable receiving groove of the sleeve-like sliding part accommodated as a component of the entire sealing device, is supported both against the groove base of the receiving groove and against the valve housing parts forming the guide for the respective sliding part, while sealing the aforementioned sealing gap. The known valve device solution has proven extremely reliable in practice and is also used for high pressure applications. Furthermore, exchanging worn O-rings for new sealing rings when needed, in general, presents no difficulty. However, the known solution reaches its limits where any leakages occurring as a result of failure of the sealing device may be the starting point for disastrous fires and explosions on oil and gas platforms, the last major accident of the Deep Water Horizon in the Gulf of Mexico having becoming familiar to the broader public.
Thus, based on this prior art, the object underlying the invention is to improve a valve device, conceivable also for high pressure applications, together with its components, such as the sealing device, so that the sealing device continues to remain fully functional, even in the event of fire, or at least, however, over a longer period of use and, accordingly, to utilize the valve device for use in risk areas, as is frequently the case on oil and natural gas platforms.
Such an object is achieved by a valve device having the features of claim 1, wherein a potential use according to the invention of this valve device is presented in claim 17, together with an associated sealing device according to the teaching of claim 18, which likewise ensures the above described requirements in connection with its use in the described valve device.
In a valve device, which includes the features of claim 1 in its entirety, it is provided according to the characterizing portion of the claim that the ring profile of at least one sealing ring of the sealing device has a ring opening that interrupts this profile in such a way that the sealing ring changes from an initial shape to an installation shape differing therefrom, in which it seals the sealing gap that can be assigned thereto with a predefinable pretension having an increased sealing force effect.
Due to the interruption of the otherwise closed ring profile resulting from the preferably slit-like ring opening, the sealing ring can be expanded within predefinable limits while increasing its inner diameter, which respectively defines its non-rounded initial shape and, with a contrastingly decreasing diameter, can be reset again to a potentially rounded installation shape up to a maximum end position, in which the adjacent ring ends abut one another when the ring opening is closed. If the sealing ring is preferably formed from a resilient material, in particular, from a suitable metal material, the reset movement following expansion occurs automatically, which helps to facilitate the fixing of sealing ring inside the valve device in the region of the sealing gap to be sealed during assembly.
It is surprising to a person of average skill in the art in the field of valve devices and, therefore, associated sealing technology, that he can obtain good sealing results with a slotted sealing ring that can assume a non-rounded initial shape, comparable to an intrinsically closed O-ring shape, which, as explained, is preferably formed from a resilient elastomer material and, accordingly, once predefined, seeks in principle to maintain its roundness in any type of shape. If the sealing ring according to the invention is first positioned in its installation shape inside the valve device with its walls and housing parts in such a way that it extends through the sealing gap to be sealed with a predefinable pretension and, therefore, with increased sealing force effect, and abuts the wall portions and housing portions also delimiting the sealing gap, then a sufficiently effective sealing of media guided within the fluid passage from the environment is already achieved. The purpose of the “fire-safe” design according to the invention is to maintain the function over a certain period, in spite of external exposure to fire from the outside; thus, it is not of primary importance whether the medium guided through the valve device is itself flammable.
This sealing effect is improved still further if, in particular in the case of high temperature, which may also exist as a result of a fire, caused, for example, by easily ignitable media guided inside the fluid passage, such as methanol, or methane hydride, which invariably arises when conveying natural gas and when transporting it, the slotted, preferably metallic sealing ring is expanded in the direction of its original initial shape and, as a result, increases the sealing force effect still further. Thus, even under extreme marginal conditions, which regularly exist in the case of fire, a safe functional sealing, which moreover, may be cost-effectively implemented and is easily maintained, is still achieved while complying with relevant safety standards.
The non-rounded sealing ring profile may also be obtained in a preferred embodiment of the valve device, in that the sealing ring in its initial shape has a slope in the form of a partial screw thread, and in that the sealing ring later lies in its installation shape inside the valve device in a slope-free plane with an existing pretension as viewed in the axial direction, so that invariably a sealing is achieved not only in the circumferential direction of the respective sealing ring, but also additionally or alternatively in an axial installation direction of the same.
The ring ends of the sealing ring delimiting the ring opening may advantageously include locking parts having complementary shapes, such that the ring ends lock one another, at least in the installation shape of the ring. Thus, the ring ends may be aligned relative to one another, such that both the ring opening prone to minimal leakage is optimally small, in particular, the abutting end face thereof that forms a seal has uniformly profiled.
In order to improve the sealing effect even more so in the case of high temperature, which can also exist as a result of fire, it may be provided that a sealing ring includes a surface, which is exposed to at least a portion of a media pressure varying within the fluid passage, and that the sealing ring with its contact surface facing away from the surface is supported at least indirectly on the valve housing in such a way that as the pressure of the medium increases, sealing surfaces of the locking parts facing one another, having complementary shapes, are pressed more forcefully together. A rapid increase of the medium pressure, as may occur, for example, in the heat build-up caused by fire or even in an explosion of a gaseous medium, results therefore in even further improvement of the sealing effect in the region of the sealing gap.
According to a particularly advantageous embodiment, it is provided that the respective locking part forms the ring end and, as viewed in the circumferential direction of the sealing ring, forms a step in such a way that in the installation shape of the sealing ring the respective step comes into laterally reversed contact, preferably as an identical component, with the other step while forming a type of labyrinth. This labyrinth repeatedly diverts the leakage fluid flowing through the ring opening, so that the flow resistance is increased and, thus, the sealing function of the sealing ring is improved in the region of the ring opening.
In a particularly advantageous embodiment, it is provided that the respective sealing ring is received in a receiving groove of a sleeve-like sliding part as a component of the sealing device, which when acted upon by an energy store, preferably in the form of at least a plate spring, abuts with a predefinable contact force the blocking element, and which is guided for axial displacement along valve housing sections forming a guide while delimiting the sealing gap. This contact of the sliding part on the blocking element may also take place via a thin fluid film diverted from the fluid passage, in order to thereby ensure the lubrication of the actuatable blocking element, regularly in the form of a closure ball. The contact force in this case ensures a certain tightness against the blocking element, even in the event of thermal-related and wear-related changes in lengths of the various components of the valve device in this region.
In one advantageous embodiment, it may be provided that the respective sealing ring, which is arranged pretensioned radially, in its circumferential direction in the receiving groove of the sliding part, extends through the sealing gap and abuts with its radial pretension the guide for the sliding part formed by valve housing. According to one further development, the respective radially pretensioned sealing ring maintains a spacing on its inner circumferential side relative to the groove base of the receiving groove to avoid an “over-defined” reception in the installation position of the sealing ring in the receiving groove over too many potential contact points, which could adversely affect the sealing effect.
In order to improve even more so the already good sealing effect on the respectively slotted ring opening of the sealing device, multiple sealing rings are arranged in an axial aligned arrangement on the outer circumference of the sliding part, wherein the ring openings of adjacent sealing rings are arranged circumferentially offset relative to one another. As a result, the free path for any occurring leakage fluid is increased, which likewise improves the desired sealing effect.
A particularly wear-resistant and thermally stable sealing ring is formed from a high temperature-resistant material and consists preferably of a non-corrosive heat-resistant chromium steel with a molybdenum additive.
The use of adjacent sealing rings of varying types ensures a tightness under varying marginal conditions, such as, for example, a sharply varying temperature. Thus, in addition to a sealing ring which, for reasons of fire protection, is especially high temperature-resistant, it is possible, inter alia, to arrange a sealing ring, also made of elastomer material, which is less temperature-resistant but, by comparison, has an improved sealing effect. Accordingly, in addition to receiving the respective sealing ring of the one type, the sliding part includes at least one additional sealing ring of a different second type, which preferably interacts with at least one support ring, and the respective additional second sealing ring and the respective support ring lie on the side of the sliding part facing away from the blocking element, in order to exclude them from the effects of higher temperatures, which could adversely affect their sealing effect.
In a particularly advantageous embodiment, the respective sealing ring of the other second type is arranged in additional receiving groove assigned thereto in the sliding part and, as viewed in the radial direction, directly abuts with a predefinable pretension the groove base of this receiving groove and, as viewed in the direction of the passage, inasmuch also seals the sealing gap inwardly.
The valve device may be installed with no risk of confusion in the valve housing independently of the installment direction. For this purpose, the respective sealing device, consisting at least of one sealing ring and the sliding part, is disposed on both sides of the blocking element to the same extent, wherein the respective sliding part has a cylindrical middle recess that is part of the fluid passage, which opens out to the fluid connection points of the valve housing on both sides of the valve.
In a particularly advantageous embodiment, even in the case of fire, a tightness is achieved for a predefined time span, even on the outwardly guided movable parts, such as, for example, an actuating shaft for the blocking element. For this purpose, it is provided that the actuating device, rotatably guided in the valve housing, is sealed from the environment by means of a sealing ring set as an additional component of the sealing device, the sealing device including at least one sealing ring of a third type, preferably, formed from a plurality of graphite rings arranged one on top of the other coaxially to the actuating axis of the blocking element, which respectively form the sealing ring of the third type.
To enable the use of components proven effective in practice, it may be provided that the valve housing is composed at least partially of individual flange parts in the form of a building block, a part of which, as an additional component of the sealing device, additionally seals the inside of the valve housing from the environment by means of sealing rings of a fourth type, primarily in the form of metal C-rings.
According to the content of claim 17, the subject matter of the invention is also a use of a valve device according to one of claims 1 through 16 in the field of oil and natural gas platforms, wherein it is designed fire-safe, at least in the area of the sealing device with sealing rings of the first type and, preferably of the fourth type, preferably complying with the fire safety standards pursuant to API607, API6FA and ISO 10497.
To account for the fact that sealing rings are subject to wear, the invention according to claim 18 also relates to a sealing device having at least one sealing ring of the one type, used as a component or replacement part for a valve device according to one of claims 1 through 16, wherein the ring profile thereof includes a ring opening that interrupts the former in such a way that the sealing ring changes from an initial shape inside the valve device to an installation shape differing therefrom, in which it exerts an increased sealing force effect with a predefined pretension.
The invention is described in greater detail below with reference to an exemplary embodiment depicted in the drawings. Therein, in a basic depiction not to scale:
The valve device according to the invention is designed in the form of a ball valve 1. The ball valve 1 includes a valve housing 2, the underside of which is cube-shaped in design according to the depiction of
The controllable blocking element 3 for closing off and releasing the flow path in the form of the fluid passage 6 is a bearing spindle 8, as part of the actuating device 4, having a longitudinal axis 7 perpendicular to the fluid passage 6, rotatably mounted in the valve housing 2, specifically, via bearing points 9 arranged inside the valve housing. The ball body, the valve ball designed as a blocking element 3, has a flow-through bore 10, which may be aligned in the housing 2 by rotating the ball spindle 8 to the bores 11 forming the medium passage, respectively, the fluid passage 6. To operate the ball valve by turning the ball spindle 8, a two-armed shift lever 12, which is connected via a coupling piece to the upper extension of the ball spindle 8 in the usual manner, and therefore not described in further detail, is located on an upper lying end section of the ball spindle 8. Connected to the aforementioned coupling piece, in turn, is a limiting disc 13 which interacts on its circumference with stop pins 14 in order to limit the possible rotational movement of the ball spindle 8 to a maximum rotation of 90°, wherein the rotary end position of the ball spindle 8 corresponds to the respective opened and closed positions of the blocking element 3.
As shown in particular in
A sealing shell in the form of a sleeve-like sliding part 23, having a front sealing edge adapted to the outer curvature of the ball-shaped blocking element 3, is located on each section bordering the ball-shaped blocking element 3 in the bores 11 which form the medium passage, respectively, fluid passage 6. The respective sliding part 23 is guided to be longitudinally displaceable or movable in the inner valve housing part 15, and abuts the blocking element 3 with a predefined pretension force on its side facing away from blocking element 3 by means of an energy store in the form of a plate spring set 24. The respective plate spring set 24 in this case is supported with its one free end against the other front side of the sleeve-like sliding part 23 and with the other end against a free front end of the thereby projecting additional housing part 16 of the valve housing 2. As shown, in particular, in
The ring opening 29 of the sealing ring 26 in this case, as viewed in the circumferential direction of the ring profile, has an initial shape larger than its installation shape shown, in which the ring opening 29 is otherwise substantially completely closed by the ring profile. If the sealing ring 26 is expanded, the inner cross-sectional area 30 thereof, which defines the central opening 27, is likewise larger than in the closed ring shape shown in the figures. Thus, in this respect, the initial shape of the sealing ring 26, based on its ring profile, is non-round, and its installation shape is round. In an alternative embodiment not further depicted, it would also be possible, as seen in the viewing direction of
In another embodiment not depicted, the radial and axial pretension for the respective sealing ring 26 may also be “overlapping”. However, the basic function of the respective sealing ring 26 is such that it is arranged pretensioned in its installation shape depicted in
As further shown in
A high temperature-resistant sealing system in conjunction with the entire sealing device is implemented with the aforementioned sealing rings 26 of the one first type. However, the sliding part 23, in addition to the receiving potential for each sealing ring 26 of the one first type, also includes a second sealing ring 36 of the second type, which preferably interacts with at least one support ring 37, wherein each additional second ring 36 and each support ring 37 lie on the side of the sliding part 23 facing away from the blocking element 3. Thus, the sealing ring 36 of the second type is regularly formed from an elastomer material which, though it enables, in principle, a proper sealing of sealing gaps, has the disadvantage that it is temperature-sensitive. The combination of the support ring 37 and the elastomer O-ring 36 for guiding and sealing movable parts, such as the sliding part 23, is sufficiently known, so that details are not further discussed here.
In conformity with the sealing arrangement 26, the respective sealing ring 36 of the second type is also arranged in an assigned second receiving groove 25 in the sliding part 23 and, as viewed in the radial direction, however, is positioned directly, and with a predefinable pretension, abutting the groove base of this receiving groove 25 and, as viewed in the direction of the guide 33, sealing the sealing gap 28. As previously mentioned, and as depicted, in particular, in
As previously explained, the actuating device 4 with spindle drive 8 is rotatably guided in the valve housing 2 and sealed from the environment by means of a sealing ring set 40 as an additional system component of the sealing device, wherein at least one sealing ring of the third type 42 is provided, which is arranged in the valve housing 2 coaxially to the actuating axis of the blocking element 3, which coincides with the longitudinal axis 7 of the ball valve 1. Preferably, a plurality of graphite rings is present, arranged coaxially to this actuating axis of the blocking element, one on top of the other, each of which form the sealing ring 42 of the third type. Such sealing rings 42 are retained compressed in an aligned arrangement as an additional valve housing part in the pot-shaped receiving body 21, which is integrated in a fixed arrangement in the upper part of the valve housing 2. A pressure compensation channel 43 is present in the ball-shaped blocking element 3 coaxially to the longitudinal axis 7 is, which emanates from the flow-through bore 10 of the blocking element 3 and, as part of the spindle drive 8, discharges into a compensation chamber 44 which, inasmuch, empties into the receiving chamber of the receiving body 21 with the graphite sealing rings 42 via an elastomer ring 42 as an additional sealing means and the support ring arranged above it. The pressure compensation channel 43 and the pressure compensation chamber 44 serve as partial pressure compensation at the thrust collar of the spindle drive 8, in order to achieve a low switching torque under pressure when the blocking element 3 is in the pass-through position.
In addition to this seal, it is provided that the valve housing 2, composed of individual flange parts and housing parts 15, 16, 17 as well as 19, 20 and 21, is designed in the form of a building block, wherein a portion of these housing parts, in particular, the parts 17 and 12 employ, as an additional component of an additional sealing system, primarily metallic C-rings, which likewise seal the interior of the valve housing 2 from the environment.
The above described valve device is suited, in particular, for a use in the field of oil and natural gas platforms. Because it is designed as fireproof at least in the area of the sealing device with sealing rings of the first, the third and, preferably, the fourth type, it is possible to readily comply with predefined fire safety standards within a broad scope. In addition, the valve device as a whole is conceived in such a way that in the event of failure, a sealing ring of the one or other type may be readily exchanged on site. The valve device according to the invention may, however, also be employed, preferably, for example, in the field of process engineering, wherever, for the purpose of conveying media, it is connected to third components, which convey and control highly flammable fluids of any type or which are located in a highly flammable environment. Thus, the valve device solution described above has no counterpart in the prior art.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 017 453.0 | Nov 2014 | DE | national |
