Sealing arrangement for a control valve and control valve

Abstract

The invention relates to a sealing arrangement (100) for a control valve (200), comprising a packing (140), a compression element (110), an abutment (120) and a spring force mechanism (130), the spring force mechanism (130) being designed to apply a spring force to the abutment (120), and the abutment (120) being designed to transmit the spring force to the compression element (110). The sealing arrangement (100) according to the invention is characterised in that the compression element (110) comprises a threaded bush (111) and a thrust piece (114), the threaded bush (111) having an external thread (112) designed to engage in an internal thread (212) of the control valve (200) in order to apply a pretensioning force to the packing (140), and the thrust piece (114) being arranged axially movably in an axial bore (113) of the threaded bush (111) and being designed to apply the spring force to the packing (140). The invention also relates to a corresponding control valve (100).

Description

[0001] noventive associates

[0002] Sealing arrangement for a control valve and control valve

[0003] The invention relates to a sealing arrangement for a control valve according to the preamble of claim 1 and to a corresponding control valve.

[0004] Sealing arrangements incorporating so-called packings are known in the prior art, and are particularly useful for sealing control valves. In these arrangements, several sealing rings made of sealing material are inserted between a housing and a component. For easier assembly, these sealing rings are usually diagonally slotted and made of a PTFE compound, graphite-filled fabric, or pressed graphite. The radial contact pressure required for sealing is typically applied axially via a pressure piece and adjusted by tightening or loosening a nut that interacts with the housing and is coupled to the pressure piece. The sealing rings rest against a stop at their end furthest from the pressure piece. This stop is either fixed to the housing or is an integral part of the housing. The components of the sealing arrangement are arranged concentrically within the housing, with the housing acting as the outer bearing and the valve stem as the inner bearing.

[0005] From DE 10 342 751 A1, a sealing arrangement is known in this context, which is effective between a housing and a component arranged in the housing. The sealing arrangement has a stop that is rigidly connected to the housing. Furthermore, the sealing arrangement is provided with a spring, a first sealing element, and an abutment. The spring rests on one side against the stop and on the other side against a pressure ring, against which the first sealing element rests. The abutment is screwed into the housing up to its flange, which serves as a stop, via a thread and is thus i

[0006] NC-2025-1271 is fixed in the direction of the first sealing element and the spring. This sealing arrangement is also called a spring-loaded stuffing box. It has the advantage that a nearly constant force, defined by the spring, is always applied, which is very important for the external sealing of control valves. Furthermore, minor wear or settling of the sealing material is compensated for by the spring. Such sealing arrangements are considered maintenance-free and have a longer service life under the same load than non-spring-loaded stuffing boxes.

[0007] DE 102014 015 889 A1 discloses an actuating valve comprising a valve stem sealed by a sealing arrangement with a sealing element designed as a packing, wherein the packing is axially compressible between a counter bearing on the valve housing and a pressure piece. The pressure piece is axially displaceable relative to the valve housing, the counter bearing being fixed in the valve housing or forming part of the valve housing. The packing can be compressed by the pressure piece, thereby achieving the sealing effect of the packing. The contact force for compressing the packing is provided by a spring, which is pre-tensioned by a preload element. By means of adjusting screws, the distance of the preload element to the counter bearing can be adjusted via the transmission element, thereby setting a preload force acting on the pressure piece.As the packing loses its axial tension when its seal weakens, the preload applied to the packing decreases, and consequently, so does the effective contact force. By readjusting the preload element, the preload and thus the seal can be increased again.

[0008] However, the known sealing arrangements for control valves are disadvantageous for various reasons. To ensure the desired sealing effect, a packing assembly typically needs to be compressed by several millimeters. This can be achieved, for example, by using a threaded bushing that creates the desired compression of the packing. However, the threaded bushing cannot automatically compensate for wear and tear on the packing over time and the resulting reduction in sealing effectiveness.

[0009] As an alternative to using a threaded bushing, it is also known to press or compress the packing assembly using a pressure piece, at least two threaded rods, and a packing jig. Disc springs can be arranged on the threaded rods above the packing jig for this purpose, which are then...

[0010] 2

[0011] The NC-2025-1271 springs can also be clamped between the nuts and the packing ring using nuts arranged on the threaded rods. The disc springs can thus exert constant pressure on the packing and ensure automatic readjustment of the sealing effect in case of wear. However, the spring travel requires a comparatively high spring column, which in turn results in an undesirably large threaded rod protrusion. The threaded rod protrusion is the portion of the threaded rod length that extends freely beyond the packing ring.

[0012] The known sealing arrangements are therefore either not self-adjusting, have an internal spring-loaded stuffing box which is not adjustable, or they have an unfavorably high protrusion of the threaded rods.

[0013] It is an object of the present invention to propose an improved sealing arrangement for a control valve.

[0014] This problem is solved according to the invention by the sealing arrangement for a control valve according to claim 1. Advantageous embodiments and further developments of the invention are described in the dependent claims.

[0015] The invention relates to a sealing arrangement for a control valve, comprising a packing, a compression element, an abutment and a spring force device, wherein the spring force device is configured to apply a spring force to the abutment and wherein the abutment is configured to transmit the spring force to the compression element.

[0016] The invention therefore proposes a sealing arrangement suitable for use in a control valve to seal the control valve against the escape of a medium transported in the control valve.

[0017] The control valve is preferably designed in such a way that it can be integrated, for example, into a control loop of a process engineering plant in order to reliably regulate a volume flow of the transported medium.

[0018] The volume flow rate is a measure of the volume of medium that flows through the control valve per unit of time.

[0019] 3

[0020] NC-2025-1271 The medium can be a liquid, gaseous, vaporous or multiphase medium.

[0021] The sealing arrangement initially comprises a packing, which provides the actual sealing function. This packing is preferably a compressible sealant that can be pressed against the sealing surfaces to be sealed against each other. Packings are typically used to seal shafts or axially moving components against liquids or gases, even when these are under pressure.

[0022] The packing is arranged to be axially compressible and can be compressed to a greater or lesser degree to provide the required tightness – for example, depending on the pressure or viscosity of the transported medium. With relatively low compression, a relatively low tightness is achieved, along with correspondingly low friction losses of the moving parts of the control valve due to the packing. Conversely, a relatively high compression of the packing achieves a relatively high tightness, but the friction of the moving parts of the control valve due to the packing is correspondingly greater.

[0023] The sealing arrangement further includes a compression element, a support and a spring force device, via which the desired compression of the packing can be adjusted.

[0024] The spring force device provides a spring force and transmits it to the abutment. Preferably, the spring force device is supported by the abutment, so that the abutment can be easily and directly subjected to the spring force.

[0025] The abutment, in turn, is designed to transmit the spring force of the spring force device to the compression element, so that the compression element is also subjected to the spring force. For this purpose, the abutment advantageously rests directly against the compression element.

[0026] According to the invention, the compression element comprises a threaded bushing and a pressure piece, wherein the threaded bushing has an external thread which is designed to engage in an internal thread of the control valve in order to apply a preload force to the packing and

[0027] 4

[0028] NC-2025-1271 wherein the pressure piece is arranged to be axially movable in an axial bore of the threaded bushing and is designed to apply the spring force to the packing.

[0029] The compression element is therefore at least two-part and includes a pressure piece as well as a threaded bushing. Since the threaded bushing has an external thread, the sealing assembly can engage with an internal thread of the control valve via the threaded bushing and thus be connected to the control valve.

[0030] By arranging the pressure piece so that it is axially movable within the axial bore of the threaded bushing, the pressure piece can transmit the spring force of the spring force device to the packing independently of the threaded bushing. Advantageously, the abutment rests exclusively on the pressure piece of the compression element, and not on the threaded bushing.

[0031] The packing is thus arranged in axial extension of the compression element in such a way that the pressure piece transmits the spring force to the packing and the threaded bushing transmits the preload force to the packing.

[0032] Both the preload force and the spring force lead to a compression of the packing and thus to an increasing sealing effect with increasing preload force or spring force.

[0033] The compression element according to the invention therefore offers the advantage that the compression of the packing necessary for achieving a seal can be effected, among other things, by the preload force of the threaded bushing. Preferably, the preload force can initially compress the packing by a few millimeters. The preload force can be applied simply by screwing the threaded bushing increasingly deeper into the internal thread of the control valve via its external thread.

[0034] Only when a desired degree of compression of the packing has already been achieved via the preload force will additional compression take place via the spring force of the spring force device.

[0035] Thus, the height of a spring column typically required in the prior art – and therefore the threaded rod protrusion – of the spring force device can be significantly reduced, since a large part of the compression of the packing is already achieved in advance via the threaded bushing.

[0036] 5

[0037] NC-2025-1271 The reduced height of the spring column of the spring force device results in advantageously reduced manufacturing costs, reduced installation space requirements and reduced leverage and bending moments on the threaded rods.

[0038] Both the threaded bushing and the pressure piece exert their respective forces on the packing; in the initial assembly state, the spring force is added to the preload force exerted by the threaded bushing through screwing in, thus acting upon and compressing the packing as well.

[0039] Initial compression of the packing during the initial assembly of the sealing assembly can be set via the threaded bushing. Subsequent and, if necessary, further compression can then be provided by the spring-loaded device. In particular, the spring force of the spring-loaded device can compensate for wear and thus volume loss of the packing during the service life of the sealing assembly by following the packing's settling process with the pressure piece, resulting in a substantially constant compression of the packing. The spring-loaded device thus enables automatic readjustment of the packing's sealing effect. This readjustment of the sealing effect can also be supported by additional manual adjustment of preload elements, which keep the springs under mechanical tension.This allows the spring force to remain largely constant over the service life of the sealing assembly. Unlike the threaded bushing, which occupies a fixed position in the internal thread of the control valve via its external thread, the pressure piece is axially movable and is adjusted by the spring force of the packing as its volume shrinks, so that the spring force continues to act on the packing and compress it.

[0040] Preload force. The force transmitted by the pressure piece and the threaded bushing is in equilibrium with the force exerted by the packing against its further compression. Unlike the spring force transmitted by the pressure piece, however, the preload force transmitted by the threaded bushing cannot be automatically adjusted, as the threaded bushing is axially fixed at its respective screw-in depth. Therefore, if the packing shrinks in volume over the service life of the sealing assembly, the portion of the total force acting on the packing from the threaded bushing decreases, while the portion of the total force transmitted by the pressure piece increases. If the packing shrinks to such an extent,

[0041] 6

[0042] NC-2025-1271, since the packing is no longer in contact with the threaded bushing, only the spring force is transferred to the packing.

[0043] For the forces transmitted by the threaded bushing and the pressure piece, this means that over the service life of the sealing assembly, both the threaded bushing and the pressure piece typically exert force on the packing during assembly. The selected preload and spring force are not necessarily equal; instead, the preload may initially be greater than the spring force. In this case, the spring force does not cause any compression of the packing that is greater than the compression caused by the preload.

[0044] However, if wear and volume shrinkage of the packing increase over the service life of the sealing assembly, it will be compressed to an increasingly smaller volume under constant force, or rather, less and less force is required to keep the packing compressed to its existing volume. Consequently, the packing offers progressively less resistance to compression to its existing volume.

[0045] Since the threaded bushing – unlike the pressure piece – is now fixed in the internal thread of the control valve, it cannot follow the packing as the packing shrinks in volume. Consequently, it transmits a progressively smaller proportion of the total force to the packing, or the packing, due to the shrinking volume of the threaded bushing, offers less and less resistance.

[0046] This results in the packing being compressed to a smaller volume by the spring force of the pressure piece alone after a certain period of use or after a certain volume loss than it was compressed by the combined spring force and preload force in its initial assembly state. From this point on, the packing moves away from the threaded bushing, and the threaded bushing no longer applies the preload force to the packing, as the packing is no longer in contact with the stationary threaded bushing.

[0047] In other words, the threaded bushing provides a preload force in the initial assembly state of the packing and then maintains its position in the internal thread of the control valve – however, it does not maintain the force transmitted to the packing as constant. The packing is compressible and therefore represents a spring element, even if it

[0048] 7

[0049] The NC-2025-1271 does not have ideal spring characteristics. As soon as the packing settles or is compressed by the pressure piece, the threaded bushing transmits less force or none at all. From that point on, the compression of the packing is caused solely by the spring force of the pressure piece.

[0050] The threaded bushing is advantageously designed to be manually tightened during the service life of the sealing assembly. This allows the proportion of the preload force on the packing to be increased again. A prerequisite for this adjustability of the threaded bushing is that it is not screwed into the internal thread of the control valve until it reaches a mechanical stop during assembly.

[0051] Alternatively, it is preferred that the threaded bushing is screwed into the internal thread of the control valve during assembly of the sealing assembly until it reaches a mechanical stop, thus preventing further screwing in or subsequent readjustment of the threaded bushing. This ensures that the packing is not excessively compressed or even damaged by accidentally overtightening the threaded bushing during assembly.

[0052] The stop can, for example, be designed as a collar around the threaded bushing and, in the final position, rest against a valve housing of the control valve.

[0053] Preferably, the pressure piece is arranged coaxially in the threaded bushing.

[0054] As already described, the spring force device is particularly advantageous in that the pressure piece is adjustable and the compression of the packing can be adjusted even during stronger setting processes.

[0055] According to a preferred embodiment of the invention, the sealing arrangement further comprises a spacer sleeve with a common bearing surface for the threaded bushing and the pressure piece, wherein the spacer sleeve is designed to apply the spring force and the preload force to the packing.

[0056] The spacer sleeve is preferably arranged axially between the packing and the compression element, with both the pressure piece and the threaded bushing resting on the common contact surface. In other words, the spacer sleeve separates the packing from the compression element.

[0057] 8

[0058] NC-2025-1271 This allows the pressure piece to transfer the spring force to the spacer sleeve, and the threaded bushing to transfer the preload force to the spacer sleeve. Both forces, i.e., the spring force and the preload force, act together on the spacer sleeve.

[0059] Since the spacer sleeve advantageously also has a single contact surface for the packing on its side axially opposite the compression element, the total force from the spring force and the preload force is transmitted to the packing via a single surface. This ensures that forces of different magnitudes do not act on the packing at different radial positions or diameters of the contact surface between the packing and the spacer sleeve. Without the common contact surface of the spacer sleeve, the packing would be subjected to force at an outer diameter by the threaded bushing and at an inner diameter by the pressure piece.If, after a certain period of use, the proportion of the total force transmitted by the pressure piece is significantly greater than the proportion transmitted by the threaded bushing—for example, because the threaded bushing no longer makes contact with the packing due to wear—this could lead to undesirable compression of the packing, particularly in the area of ​​the packing's contact surface. The packing can then react to the pressure of the pressure piece not only with compression but also by shifting radially outside the pressure piece, as this space is not filled by the non-adjustable threaded bushing. As a result, the packing's sealing effect may diminish.

[0060] Since the spacer sleeve is designed as a sleeve, it has a hollow cylindrical shape open at both ends. The contact surface for the threaded bushing and the pressure piece is accordingly ring-shaped. Likewise, the contact surface for the packing is also ring-shaped.

[0061] According to a particularly preferred embodiment of the invention, it is provided that the threaded bushing and the pressure piece each stand in contact with the spacer sleeve over a substantially identical ring section width of the spacer sleeve.

[0062] The term "ring section width" refers to a portion of the width of the annular bearing surface for the threaded bushing and the pressure piece. Since the pressure piece is advantageously arranged coaxially in the threaded bushing, the

[0063] 9

[0064] The NC-2025-1271 threaded bushing rests with one axial end on an outer section of the annular common bearing surface, and the pressure piece rests with one axial end on an inner section of the annular common bearing surface. Each of these sections is itself annular and has a radial width, namely the ring section width. The sum of the ring section widths over which the threaded bushing and the pressure piece are in contact with the spacer sleeve thus yields the width of the annular bearing surface.

[0065] By ensuring that the threaded bushing and the pressure piece are in contact with the spacer sleeve over an essentially identical ring width, it can be easily ensured that, with essentially identical spring and screw forces, essentially identical pressures are transmitted from the threaded bushing and the pressure piece to the spacer sleeve. This results in a uniform load and force distribution.

[0066] Preferably, the compression element, the abutment and the spring force device are made of metal.

[0067] For the compression element and the abutment, metallic alloys such as steel alloys, stainless steel alloys, nickel-based alloys or aluminum alloys are preferably suitable as metals.

[0068] Spring steel is preferably suitable for the spring force device and in particular for the springs of the spring force device.

[0069] This makes the sealing arrangement mechanically stable and temperature-resistant, and particularly able to withstand comparatively high internal pressures and high temperatures.

[0070] According to a further preferred embodiment of the invention, the spacer sleeve consists of several individual spacer rings arranged axially to each other, wherein the several individual spacer rings can be combined to produce a defined height of the spacer sleeve.

[0071] The spacer sleeve can therefore be manufactured from any number of spacer rings, or as required, by axially arranging the individual spacer rings next to each other. This offers the advantage that different packing configurations can be used very easily by varying the number of spacer rings, or different compression levels can be achieved with identical packing configurations.

[0072] 10

[0073] NC-2025-1271 without having to adapt the compression element to the specific requirements. In other words, an identical compression element can always be used for different packings or different compressions.

[0074] The spacer sleeve represents the axial extension of the compression element to the packing, so that the respective requirements for the compression element can be met by adjusting the spacer sleeve.

[0075] Therefore, it is not necessary to stock a large number of different compression elements for different applications. Instead, the compression elements can be designed as identical parts. This simplifies manufacturing and reduces storage costs.

[0076] A single spacer ring can, for example, have a diameter ranging from 0.5 mm to 300 mm. Preferably, a single spacer ring can have a height of 0.5 mm, 10 mm, 15 mm, 25 mm, or 30 mm.

[0077] Preferably, the individual spacer rings are identical components or at least groups of identical components. This also results in a large number of identical parts that can be combined as needed to create the required spacer sleeve. This further simplifies manufacturing and reduces storage costs.

[0078] According to a further preferred embodiment of the invention, seals are provided for sealing both between the threaded bushing and the pressure piece, and between the threaded bushing and the valve housing. Particularly preferably, a total of three seals are provided, wherein a first and a second seal serve for sealing between the threaded bushing and the pressure piece, and a third seal serves for sealing between the threaded bushing and the valve housing.

[0079] The two seals between the threaded bushing and the pressure piece prevent the transported or flowing medium from escaping in the area between the threaded bushing and the pressure piece. Since the pressure piece is axially movable relative to the threaded bushing, at least to a small extent, the provision of two seals results in an improved sealing effect that also tolerates the axial movement of the pressure piece. Preferably, the two seals are located between ii

[0080] NC-2025-1271, the threaded bushing and the pressure piece are each arranged in a groove in the threaded bushing and the pressure piece, respectively, to prevent the seals from shifting during axial movement of the pressure piece in the threaded bushing.

[0081] Advantageously, the two seals, i.e., the first and the second seal, are axially spaced apart from each other by at least half the axial length of the pressure piece between the threaded bushing and the pressure piece, i.e., one of the two seals is arranged in the region of a first axial end of the pressure piece and the other of the two seals is arranged in the region of a second axial end of the pressure piece.

[0082] The third seal prevents the medium from leaking between the threaded bushing and the valve housing.

[0083] Preferably, the third seal is arranged above the external thread of the threaded bushing, particularly preferably in an outlet area of ​​the axial bore of the valve housing in which the compression element is arranged.

[0084] Designing the first or second seal as an O-ring is both cost-effective and efficient. O-rings are readily available in many different sizes and diameters at low cost, easily replaceable during maintenance or repairs, and, when properly installed, provide excellent sealing performance.

[0085] According to a further preferred embodiment of the invention, the spring force device comprises at least two spring accumulators, each with at least one spring, a contact surface on the abutment, a threaded rod and a preload element, wherein the at least one spring is clamped on the threaded rod between the contact surface on the abutment and the preload element, so that the abutment is subjected to the spring force.

[0086] The spring-loaded device is preferably connected to a valve housing of the control valve via threaded rods, with the threaded rods preferably anchored vertically at a first axial end in a cover of the valve housing. The anchoring or arrangement of the threaded rods in the cover can be achieved, for example, by screwing or riveting. Provided the

[0087] 12

[0088] When NC-2025-1271 threaded rods are riveted into the cover, the first axial end does not necessarily have to have an external thread.

[0089] At least one second axial end of the threaded rods preferably has an external thread, by means of which the threaded rods can each be screwed to an internal thread of a preloading element, for example a screw nut.

[0090] The threaded rods protrude through the abutment with their axially central area, which has corresponding openings for the threaded rods.

[0091] The abutment also has an opening for the valve stem of the control valve, in particular for the axial part of the valve stem that protrudes from the compression element. The diameter of the opening for the valve stem in the abutment is preferably dimensioned such that the valve stem, but not the compression element, can protrude through the opening. Thus, the abutment rests on the compression element with the edge surrounding the opening. Advantageously, the abutment rests exclusively on the pressure piece of the compression element, but not on the threaded bushing of the compression element.

[0092] Springs are clamped between the preload elements and the abutment. These springs are supported by the preload elements and exert a force on the abutment. This force is the spring force and is transmitted from the abutment to the pressure piece, which in turn applies the spring force to the packing or spacer sleeve.

[0093] By progressively screwing the preload elements in or out along the external threads of the threaded rods, the spring force on the abutment can be increased or reduced, and the compression and sealing effect of the packing can be increased or reduced to the same extent.

[0094] The abutment thus functionally represents a force transmission element, which provides the spring force acting on the packing via the adjustment of the preload elements.

[0095] The spring elements are preferably disc springs, which can provide a comparatively large spring force.

[0096] The inventive design of the compression element with the threaded bushing and the pressure piece, as already described, allows the height to be adjusted.

[0097] 13

[0098] The length of the spring column of the NC-2025-1271 is significantly reduced compared to known control valves. This allows for the use of comparatively shorter threaded rods and a corresponding reduction in the number of springs required on each threaded rod.

[0099] The threaded rods are preferably stud bolts.

[0100] According to a particularly preferred embodiment of the invention, it is provided that the at least one spring is arranged directly on the threaded rod.

[0101] Since the spring column in the sealing arrangement according to the invention is comparatively shorter, as already described, the springs can be arranged directly on the threaded rods. A sleeve, conventional in the prior art, for receiving the springs on the threaded rods can advantageously be omitted. This reduces the number of components required and lowers manufacturing costs and assembly time.

[0102] The invention further relates to a control valve. The control valve is characterized by the fact that it comprises a sealing arrangement according to the invention.

[0103] This results in the same advantages for the control valve according to the invention as already described.

[0104] The control valve according to the invention can be either a so-called lift valve or a so-called swivel valve.

[0105] In a lift valve, the actuation of an actuator to control the volume flow of the transported medium takes place in the form of a linear movement.

[0106] In contrast, with a swivel valve, the actuating element for controlling the volume flow of the transported medium is operated in the form of a rotary movement.

[0107] According to a preferred embodiment of the invention, the control valve further comprises a valve housing with a bore, wherein the bore has an internal thread which is designed for screwing in the threaded bushing via its external thread.

[0108] This allows the threaded bushing of the compression element to be screwed into the bore in order to apply the preload force to the packing. Each

[0109] 14

[0110] The further the threaded bushing is screwed into the bore (NC-2025-1271), the greater the preload force applied to the packing.

[0111] According to a further preferred embodiment of the invention, the threaded bushing has a collar-like stop which is designed to mechanically limit the screwing of the threaded bushing into the bore.

[0112] By screwing the threaded bushing into the bore, high screw forces can be easily generated even with low screw-in torques, which are then applied to the packing.

[0113] The collar-like stop ensures that the threaded bushing is not screwed too deep into the bore and that the preload force does not exceed a maximum value.

[0114] This makes it easy and reliable to prevent excessive compression of the package.

[0115] The collar-like stop can also be advantageously hexagonal on its outer circumference and, in particular, conform to a common standard for hexagonal screws. This allows the threaded bushing to be easily screwed into the bore using standard tools.

[0116] According to a particularly preferred embodiment of the invention, the control valve further comprises a valve stem, wherein the compression element is arranged in the bore of the valve housing, wherein the valve stem is axially movable in the pressure piece and projects beyond the pressure piece in both axial directions, and wherein the packing is arranged radially between the valve stem and a wall of the bore and axially between the compression element and a stop of the valve housing.

[0117] As previously described, the compression element is positioned in the valve housing bore via the external thread of the threaded bushing. The pressure piece has a coaxially designed axial bore within which the valve stem is movably mounted. In other words, the valve stem is arranged coaxially and movably within the pressure piece, and the pressure piece is in turn arranged coaxially and movably within the threaded bushing, which is screwed into the valve housing bore and thus axially fixed.

[0118] 15

[0119] NC-2025-1271 The valve stem serves to actuate an actuator of the control valve.

[0120] The packing is arranged in a space within the valve housing, which is axially limited on one side by the compression element and on the other by the stop in the valve housing. If a spacer sleeve is used, the space is axially limited by the spacer sleeve and the stop.

[0121] Radially, the space for arranging the packing is bounded inwards by the valve stem and outwards by the wall of the bore in the valve housing. This space is also known as the packing space.

[0122] The packing thus provides a seal between the valve stem and the valve body to prevent leakage in this area of ​​the control valve. By increasing the force on the packing—that is, the preload force transmitted by the threaded bushing and the spring force transmitted by the pressure piece—it is further compressed axially and fits more tightly radially against the valve stem and the bore wall, thereby increasing the sealing effect of the packing. However, this also increases the friction between the valve stem and the packing during axial movement of the valve stem, which can negatively affect the positioning accuracy of the actuator and the service life of the packing.

[0123] Preferably, the actuating element is designed as a so-called perforated cone in a valve seat.

[0124] The term "perforated cone" refers to a specific hollow cylinder with a perforation mask that can be adapted to the specific requirements.

[0125] Depending on the specific application, the desired compression of the packing can be adjusted as needed, for example, based on the state of matter of the transported medium, its pressure, its viscosity, or the packing materials used. In particular, different packing materials such as aramid, graphite, or PTFE require different compression levels to provide the best possible sealing effect.

[0126] According to a further preferred embodiment of the invention, the pressure piece has a radially circumferential collar at its axial end abutting the abutment, and the threaded bushing has an increase in the diameter of the axial bore in the area of ​​the collar-like stop.

[0127] 16

[0128] NC-2025-1271 wherein the diameter enlargement is designed to accommodate the radially running collar axially, at least partially.

[0129] The thickening axially limits the movement of the pressure piece in the threaded bushing towards the packing when the thickening comes into contact with the threaded bushing. This advantageously prevents the spring force transmitted from the pressure piece to the packing from becoming significantly greater than the preload force transmitted by the threaded bushing, and thus ensures that the packing is subjected to a substantially uniform total force from the pressure piece and the threaded bushing.

[0130] A further advantage resulting from the increased diameter of the axial bore and the consequent capacity to accommodate the radially circumferential collar of the pressure piece is that the overall height of the control valve can be kept as low as possible. Because the radially circumferential collar can be accommodated within the increased diameter, it does not rest axially against the end of the threaded bushing and therefore does not extend the overall length of the compression element.

[0131] According to a further preferred embodiment of the invention, the control valve further comprises an actuator, wherein the actuator is designed as an electric actuator or as a pneumatic actuator.

[0132] The actuator preferably actuates the valve stem of the control valve, which in turn actuates the actuating element of the control valve. The invention is explained below by way of example with reference to embodiments shown in the figures.

[0133] They show:

[0134] Fig. 1 shows an exemplary and schematic embodiment of a sealing arrangement according to the invention for a control valve and

[0135] Fig. 2 shows an exemplary and schematic embodiment of a control valve according to the invention.

[0136] Identical objects, functional units, and comparable components are designated across all figures using the same reference symbols. These objects, functional units, and comparable components are distinguished by their technical characteristics.

[0137] 17

[0138] NC-2025-1271 features are executed identically unless explicitly or implicitly otherwise stated in the description.

[0139] Fig. 1 shows by way of example and schematically a possible embodiment of a sealing arrangement 100 according to the invention for a control valve 200 designed as a lift valve 200.

[0140] The sealing assembly 100 comprises a packing 140, a compression element 110, an abutment 120, and a spring force device 130. The spring force device 130 is configured to apply a spring force to the abutment 120. The abutment 120, in turn, is configured to transmit the spring force to the compression element 110.

[0141] The compression element 110 is designed in two parts and comprises a threaded bushing 111 and a pressure piece 114.

[0142] The threaded bushing 111 has an external thread 112, which is designed to engage with an internal thread 212 of a valve housing 210 of the control valve 200 in order to apply a preload force to the packing 140. The preload force results from the screw-in depth of the threaded bushing 111 into the valve housing 210.

[0143] The pressure piece 114 is arranged coaxially and axially movable in an axial bore 113 of the threaded bushing 111 and is designed to apply spring force to the packing 140.

[0144] The sealing assembly 100 further comprises a spacer sleeve 150 with a common bearing surface for the threaded bushing 111 and the pressure piece 114. The spacer sleeve 150 is designed to absorb the spring force of the pressure piece 114 and the preload force of the threaded bushing 111 in the initial state after assembly of the sealing assembly and to transmit them to the packing 140. Thus, in the initial state, the spacer sleeve 150 exerts the spring force applied by the pressure piece 114 and the preload force applied by the threaded bushing on the packing 140. However, if the packing 140 settles or shrinks in volume during the service life of the sealing assembly 100, the threaded bushing 111 may no longer bear against the spacer sleeve 150, and consequently, no force may be exerted on the packing 140.

[0145] 18

[0146] The NC-2025-1271 spacer sleeve 150 transmits the force. Then, the spacer sleeve 150 applies spring force exclusively to the packing 140.

[0147] For example, the threaded bushing 111 and the pressure piece 114 each rest against the spacer sleeve 150 over an identical ring width. Since the threaded bushing 111 is located on the outside and the pressure piece 114 on the inside, the contact area of ​​the threaded bushing 111 with the spacer sleeve 150 is slightly larger than the contact area of ​​the pressure piece 114 with the spacer sleeve 150, due to the larger diameter or circumference of the threaded bushing 111, given the identical ring width.

[0148] For example, the spacer sleeve 150 consists of two axially aligned spacer rings 151, 152. The spacer rings 151, 152 are identical parts that can, in principle, be combined in any quantity to produce a spacer sleeve 150 of the desired length.

[0149] The valve housing 210 also has a bore 211 with an internal thread 212, into which the threaded bushing 111 is screwed via its external thread 112. The compression element 110 is thus arranged in the bore 211 of the valve housing 210. The valve stem 213 is axially movable and mounted in the pressure piece 114, and projects beyond the pressure piece 114 in both axial directions.

[0150] The packing 140 is arranged radially between the valve stem 213 and a wall of the bore 211 and axially between the compression element 110 and a stop of the valve housing 210 in the so-called packing space.

[0151] As can be seen further in Fig. 1, two seals 115, 116 are provided for sealing between the threaded bushing 111 and the pressure piece 114. A further seal 214 is provided for sealing between the threaded bushing 114 and the valve housing 210. The three seals 115, 116, 214 mentioned are, for example, O-rings.

[0152] The spring force device 130 of the sealing arrangement 100 consists, for example, of two spring accumulators 131, which in turn each consist of a spring 132, a contact surface 121 on the abutment 120, a threaded rod 133 and a preload element 134.

[0153] 19

[0154] NC-2025-1271 The two springs 132 are, for example, disc springs 132. The preload elements 134 are, for example, nuts 134. The threaded rods 133 are, for example, stud bolts 133.

[0155] The disc springs 132 are arranged directly on the stud bolts 133 and are clamped axially between the contact surface 121 on the abutment 120 and the screw nuts 134, so that the abutment 120 is subjected to the spring force accordingly.

[0156] The pressure piece 114 also has a thickening 119 at its axial end 118, which abuts the abutment 120, and the threaded bushing 111 has an increase in the diameter of the axial bore 113 in the area of ​​the collar-like stop 117. The increase in diameter is designed to accommodate the thickening 119 at least partially axially.

[0157] Fig. 2 shows an exemplary and schematic embodiment of a possible embodiment of a control valve 200 according to the invention, which is designed as a lift valve 200.

[0158] The control valve 200 comprises a sealing arrangement 100, as described in Fig. 1. Furthermore, the control valve 200 comprises a valve housing 210 with a bore 211 and a valve stem 213.

[0159] As can also be seen in Fig. 2, the threaded bushing 111 has a collar-like stop 117, which is designed to mechanically limit the screwing of the threaded bushing 111 into the bore 211. The collar-like stop 117 is hexagonal in shape, so that known tools, such as wrenches, can engage the collar-like stop 117 to screw the threaded bushing 111 into the internal thread 212.

[0160] 20

[0161] NC-2025-1271 Reference numeral list

[0162] 100 sealing arrangement

[0163] 110 compression element

[0164] 111 Threaded bushing

[0165] 112 external threads

[0166] 113 Axial bore

[0167] 114 Printed piece

[0168] 115 Seal

[0169] 116 Seal

[0170] 117 collar-like stop

[0171] 118 Axial end of the pressure piece

[0172] 119 radially around the running collar of the pressure piece

[0173] 120 abutments

[0174] 121 Plant area

[0175] 130 Spring force device

[0176] 131 spring accumulators

[0177] 132 Spring, disc spring

[0178] 133 threaded rods, stud bolts

[0179] 134 Preload element, screw nut

[0180] 140 pack

[0181] 150 spacer sleeve

[0182] 151 spacer ring

[0183] 152 spacer ring

[0184] 21

[0185] NC-2025-1271 00 Control valve, lift valve 10 Valve body 11 Bore in valve body 12 Internal thread 13 Valve stem 13 Valve body stop 14 Seal

[0186] NC-2025-1271

Claims

Patent claims 1. Sealing arrangement (100) for a control valve (200), comprising a packing (140), a compression element (110), an abutment (120) and a spring force device (130), wherein the spring force device (130) is configured to apply a spring force to the abutment (120) and wherein the abutment (120) is configured to transmit the spring force to the compression element (110), characterized in that the compression element (110) comprises a threaded bushing (111) and a pressure piece (114), wherein the threaded bushing (111) has an external thread (112) configured to engage in an internal thread (212) of the control valve (200) in order to apply a preload force to the packing (140) and wherein the pressure piece (114) is arranged to be axially movable in an axial bore (113) of the threaded bushing (111). is and is designed to apply spring force to the packing (140).

2. Sealing arrangement (100) according to claim 1, characterized in that it further comprises a spacer sleeve (150) with a common bearing surface for the threaded bushing (111) and the pressure piece (114), wherein the spacer sleeve (150) is designed to apply the spring force and the preload force to the packing (140).

3. Sealing arrangement (100) according to claim 2, 23 NC-2025-1271 characterized in that the threaded bushing (111) and the pressure piece (114) each have an essentially identical ring section width of the spacer sleeve (150) in contact with the spacer sleeve (150).

4. Sealing arrangement (100) according to at least one of claims 1 to 3, characterized in that the spacer sleeve (150) consists of several individual spacer rings (151 , 152) arranged axially to each other, wherein the several individual spacer rings (151 , 152) can be combined to produce a defined height of the spacer sleeve (150).

5. Sealing arrangement (100) according to at least one of claims 1 to 4, characterized in that two seals (115, 116) are provided for sealing between the threaded bushing (111) and the pressure piece (114) and a seal (214) is provided for sealing between the threaded bushing (114) and the valve housing (210).

6. Sealing arrangement (100) according to at least one of claims 1 to 5, characterized in that the spring force device (130) comprises at least two spring accumulators (131) each with at least one spring (132), a contact surface (121) on the abutment (120), a threaded rod (133) and a preload element (134), wherein the at least one spring (132) is clamped on the threaded rod (133) between the contact surface (121) on the abutment (120) and the preload element (134), so that the abutment (120) is subjected to the spring force.

7. Sealing arrangement (100) according to claim 6, characterized in that the at least one spring (132) is arranged directly on the threaded rod (133). 24 NC-2025-1271 8. Control valve (200) comprising a sealing arrangement (100) according to at least one of claims 1 to 7.

9. Control valve (200) according to claim 8, characterized in that it further comprises a valve housing (210) with a bore (211), wherein the bore (211) has an internal thread (212) which is designed for screwing in the threaded bushing (111) via its external thread (112).

10. Control valve (200) according to claim 9, characterized in that the threaded bushing (111) has a collar-like stop (117) which is designed to mechanically limit the screwing of the threaded bushing (111) into the bore (211).

11. Control valve (200) according to at least one of claims 9 and 10, characterized in that it further comprises a valve stem (213), wherein the compression element (110) is arranged in the bore (211) of the valve housing (210), wherein the valve stem (213) is axially movable in the pressure piece (114) and projects beyond the pressure piece (114) in both axial directions, and wherein the packing (140) is arranged radially between the valve stem (213) and a wall of the bore (211) and axially between the compression element (110) and a stop (214) of the valve housing (210).

12. Control valve (200) according to at least one of claims 8 to 11, characterized in that the pressure piece (114) has a radially circumferential collar (119) at its axial end (118) abutting the abutment (120), and 25 NC-2025-1271 that the threaded bushing (111 ) in the area of ​​the collar-like stop (117) has a diameter increase of the axial bore (113), wherein the diameter increase is designed to axially accommodate the radially running collar (119) at least partially.

13. Control valve (200) according to at least one of claims 8 to 12, characterized in that it further comprises an actuator, wherein the actuator is designed as an electric actuator or as a pneumatic actuator. NC-2025-1271

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