VALVE FOR CONTROLLING AND / OR REGULATING A FLUID FLOW

Description

TECHNICAL FIELD

[0001] The present invention relates to a valve or fitting for arrangement in a pipeline and for controlling and / or regulating a fluid flow, in particular a steam flow, according to the preamble of claim 1. BACKGROUND

[0002] Such valves for controlling and / or regulating a fluid flow generally comprise a valve seat and a valve member that is mounted for axial movement. The valve member usually has a valve stem and, at one end thereof, a valve body. To actuate the valve, i.e. for the axial movement of the valve member, in particular the valve body, a valve drive is also provided which is directly or indirectly connected to the valve stem in a force-transmitting manner. This allows the valve body to be lifted from the valve seat to open the valve, thus enabling flow through the pipeline or valve. To bring the valve into a closed position, the valve body is brought back into contact with the valve seat, thus blocking fluid flow through the pipeline.

[0003] The valve of the present application is used, for example, in pipelines that convey live steam, for example, to a steam engine. Especially at high fluid pressures and high fluid temperatures, which occur, for example, in the above-mentioned application, the valve must ensure that the pipeline is reliably sealed when closed, despite the high load.

[0004] The high temperatures cause thermal changes, particularly material expansion, which can lead to a change in the valve's operating point. This can result in the valve element, particularly the valve body, being pressed into the valve seat with excessive force. However, repeated actuation of the valve results in significant wear on the valve body and / or valve seat, which can lead to the valve leaking when closed. Furthermore, this wear can cause bypass flows in the valve and malfunctions in the overall system in which the valve is used to control and / or regulate a fluid flow.

[0005] Furthermore, it may also happen that the valve does not close completely due to material expansion and consequently leakage occurs.

[0006] Therefore, state-of-the-art valves regularly require complex positioning of the valve body on the valve seat and / or a relatively complex dynamic adjustment of the operating point depending on the prevailing temperatures.

[0007] The prior art currently includes valves for controlling or regulating fluid flow that are designed to facilitate the interaction of the valve body and the valve seat by means of a conical valve seat. In particular, this guides the valve body into the valve seat, which is intended to lead to reliable and low-wear closure even under high forces. However, even these valves do not deliver satisfactory results at high temperatures and pressures.

[0008] Furthermore, US 5,145,148 A discloses a solenoid valve for controlling and / or regulating a hydraulic flow, e.g. in a hydraulic adaptive breaking system.

[0009] According to its abstract, EP 0 952 331 A2 also discloses an exhaust gas recirculation valve which, in order to prevent a functional failure when the valve disk sticks to the valve seat due to deposits, for example when the internal combustion engine is switched off, is constructed in such a way that it is possible to store kinetic energy in a component which can be brought into operative connection with a head at the free end of the valve rod after overcoming a detent position serving to increase the force.

[0010] In particular, neither the problem caused by thermal expansion nor the increased wear can be solved by such a valve design. DESCRIPTION OF THE INVENTION

[0011] It is therefore an object of the present invention to provide a valve for controlling and / or regulating a steam flow, with which the aforementioned problems can be at least partially eliminated and in which a reliable and permanent closing or shutting off of the valve is ensured despite high temperatures and pressures.

[0012] When reference is made to high temperatures in this application, this applies in particular to a steam flow, i.e., temperatures above 100°C. Furthermore, for the efficient operation of a steam engine, live steam parameters with a fluid pressure of 150 bar and fluid temperatures above 500°C are not uncommon. With such parameters, thermal expansion of the valve member, in particular of the valve stem, of several millimeters to over 10 mm in the axial direction of the valve is to be expected. This expansion must be compensated for by the valve in order to ensure fluid flow when the valve is closed and to enable correct control and / or regulation of the fluid flow when the valve is (partially) open.

[0013] In order to achieve this, the present application is based on the idea that the valve train and the valve body can interact to transmit force in order to lift the valve body from the valve seat, but the valve train and the valve body are decoupled from each other to close the valve.

[0014] Decoupling means that the valve train and the valve body can move relative to each other.

[0015] This makes it possible to avoid any excessive forces that may occur between the valve body and the valve seat when closing, to ensure that the valve body and valve seat find each other reliably and that any thermally induced expansion can be automatically compensated for, at least when the valve is closing, or has no influence on the closing process.

[0016] The above object is achieved, for example, by a valve having the features of claim 1. Preferred embodiments and features as well as advantages can be found in the subclaims, the following description, and the drawings.

[0017] According to a first aspect, the valve (or fitting) for controlling and / or regulating a steam flow comprises a valve seat and a valve body. The valve body may be part of a valve member. The valve member may further comprise an axially movable valve stem, which is connected to the valve body and mounted in a valve housing.

[0018] The term "axial" can be understood as along the main axis of the valve member, the valve stem or the valve train and corresponds to the longitudinal direction of said elements.

[0019] The valve further comprises a valve train that cooperates with the valve body to transmit force to axially move the valve body and lift the valve body from the valve seat. The valve train can act directly on the valve body. Furthermore, the valve train can also act indirectly on the valve body via at least one other element, such as a valve stem. In this case, the valve train and the valve body are decoupled from each other. The decoupling can be implemented such that the valve train can move independently of the valve body.

[0020] For example, the valve train, which may have an external thread on its outer circumferential surface, is screwed to a rotating spindle via the threads of the external thread, so that a rotational force applied externally to the rotating spindle to drive the valve can be transferred by the rotating spindle into a purely axial movement of the valve train. In this case, the valve train with its external thread can be viewed as a spindle that interacts with the rotating spindle. This means that a relative force is applied via the valve train to move the valve body axially by means of the valve train, in order to lift the valve body from the valve seat. This allows a certain degree of valve opening to be achieved.

[0021] The valve element, including the valve stem and valve body, is movable along an axial direction. When the valve is closed, the valve body closes the pipeline by interacting with the valve seat. Fluid flow is blocked and the pipeline is shut off. Furthermore, the valve body can be lifted in the axial direction, opening the valve and allowing fluid flow through the pipeline.

[0022] The shape of the valve body and / or the valve seat can be freely selected as long as the interaction of the valve seat and the valve body to shut off the fluid flow in the pipeline can be ensured.

[0023] In addition, the valve body is pressed into the valve seat by a spring element. The spring force of the spring element can be predefined and adjusted or adapted as needed. Furthermore, the valve train cooperates with the valve body to transmit force, preferably directly, to axially move the valve body, lifting the valve body from the valve seat. The valve train and the valve body can be moved independently of each other.

[0024] "Force-transmitting interaction" can be understood here as the valve train being able to apply force to the valve body without the valve train being rigidly connected to the valve body. This means that when the valve is closed, the valve body is not connected to the valve train or is not in contact with it. This makes it possible to achieve the decoupling of the valve train from the valve body described above, thus enabling low-wear, simple, and self-centering positioning of the valve body on the valve seat without the valve train having to be connected to the valve body.

[0025] The design of the spring element, which presses against the valve body and is not connected to the valve train, allows for a so-called "cartridge" design of the valve member with the spring element, thus allowing for easy replacement of these elements. This allows for easy valve maintenance.

[0026] This makes it possible to achieve a decoupling of the axial movement and the sealing of the fluid flow. Furthermore, tension and distortion in the valve can be prevented. This reduces wear, increases service life, and maintains the valve's long-term, low-friction functionality.

[0027] In addition, the valve train, in particular an axially movable shaft of the valve train, is spaced from the valve body when the valve is closed and comes into contact with the valve body to lift the valve body off the valve seat.

[0028] According to such a design, when the valve is actuated, i.e., when the valve opens and the valve body lifts off the valve seat, contact can be created between the valve train, in particular the axially movable shaft, and the valve body. Thus, when the valve is held in a closed state, there is no contact between the valve train and the valve body. This prevents thermal stresses in the valve and compensates for thermal expansion. This means that a decoupling between the valve body and the valve train is achieved.

[0029] In addition to decoupling the valve body and the valve train, automatic valve closure can be achieved using steam pressure. This means that the steam pressure presses the valve body onto the valve seat without the valve train having to exert pressure on the valve body. This not only drastically reduces wear, particularly due to the forces of the valve train that would otherwise be required when the valve is closed, but also improves efficiency, as significantly less energy is required. Furthermore, the valve closure using steam pressure can achieve self-centering of the valve body.

[0030] This is particularly advantageous at particularly high pressures, since, for example, high counterforces from a driven valve train are not necessary when the valve is closed, and a "self-closing" occurs via steam pressure. "Pinching" or "jamming" of the valve train can thus be completely prevented. The valve "helps itself," because the higher the steam pressure, the stronger the valve's closing effect.

[0031] According to a further aspect, the spring force of the spring element presses the valve body into the valve seat in a first direction. The valve train, in particular the axially movable shaft of the valve train, is instead movable in an opposite second direction. According to such an embodiment, it is possible for the valve body and the valve train to be moved in opposite directions, and only when the valve opens, i.e. when the valve body is lifted off the valve seat, does the valve body come into force-transmitting contact with the valve stem. This means that when the valve opens, the valve train counteracts the spring force of the spring element and the steam pressure, thus opening the valve. However, the spring force is to be understood as merely a supporting function of the valve closure, since the majority of the closing force is achieved by the steam pressure.

[0032] In one variant, the valve body has at least one spherical portion that interacts with the valve seat in a closed position of the valve, in which the valve body is pressed into the valve seat. It should be noted at this point that this aspect can also be implemented independently of the above aspects concerning the damper and the spring element.

[0033] It is preferred that the valve body is a ball.

[0034] Such designs make it possible to further reduce wear. This is primarily due to the spherical surface of the valve body allowing the valve body to self-center on the valve seat. This prevents wedging or "pinching" of the valve body in the valve seat and avoids stresses in the valve. Furthermore, the spherical surface of the valve body allows the forces generated to be evenly distributed across the entire surface of the valve body. Furthermore, such a simple design ensures that the valve seat always interacts with the spherical valve body in the correct position. This means that the same forces can always be used to press the valve body into the valve seat.

[0035] Consequently, simple, dynamic, precise and low-wear positioning and use of the valve is possible.

[0036] According to a further aspect, the valve body is freely movable in a convex-shaped receptacle. The receptacle for the valve body can be formed on the valve member, in particular on the valve stem. Furthermore, it is possible for the spherical valve body to be mounted on the axially movable stem. This allows the spherical body to rotate freely, thus further improving the positioning and centering of the valve body on the valve seat.

[0037] According to a further aspect, the axial end of the valve body facing the valve train has a surface that is beveled toward the center axis of the valve body. This beveled surface is arranged such that a recess is formed on the valve body. The angle of inclination of the beveled surface of the valve body to a horizontal line is between 0.5° and 1.5°, preferably 1°.

[0038] Here, the "angle of inclination" is to be understood as the angle between an axis along the beveled surface of the valve body (first angle leg) and a horizontal axis (second angle leg), which preferably intersects the axis along the beveled surface at the longitudinal axis of the valve body (angle vertex).

[0039] This allows for simple, precise, and low-wear positioning and use of the valve. Furthermore, the beveled surface ensures a secure seal against the steam flow.

[0040] According to a further aspect, the valve seat is rectangular in axial longitudinal section. In other words, the valve seat is merely a bore. The diameter of the valve seat is smaller than the diameter of the valve body, in particular of the aforementioned spherical portion, if present.

[0041] Such a simple design makes it possible to easily and wear-resistantly center and position the valve body on the valve seat when the operating points of the valve body and valve seat change due to temperature. Such a design also makes it possible to produce a cost-effective valve seat that, when combined with the valve body, still allows for adequate shutoff of the pipeline.

[0042] In particular, the valve body's design with a spherical section allows the valve body to project beyond the valve seat by a certain amount, allowing for easy centering of the valve body during the valve closing process—i.e., the interaction between the valve body and the valve seat. This design also allows the valve body of the valve element to rest on the valve seat only via linear contact, allowing for simple positioning of the valve body of the valve element even in the event of thermal expansion or thermal influences on the operating points.

[0043] According to a further aspect, the hardness of the material of the valve body is greater than that of the material of the valve seat.

[0044] Such a design makes it possible to further reduce wear and adequately transfer the forces acting on the axially movable valve body to the valve seat, even under loads of high fluid temperatures and pressures. The "hardness" of the material is understood in mechanical engineering as the mechanical resistance that a material offers to the mechanical penetration of another body. The increased hardness of the valve body material makes it possible to reduce wear on the valve body or valve element.

[0045] According to a further aspect, a proximity sensor, preferably an inductive proximity sensor, is provided to detect the axial movement of the valve train.

[0046] Such a design makes it possible to enable axial movement of the valve train without thermal coupling, i.e., without a direct connection between the proximity sensor and the valve train. Such a design also makes it possible to determine the axial travel of the valve train with a simple design.

[0047] According to a further aspect, a displacement sensor is provided to determine an axial movement of the valve stem.

[0048] This has the advantage that even with thermally changing operating points between the valve body and the valve seat, precise measurement of the closing or opening process of the valve is possible. Furthermore, with such a design, it is possible to determine the position of the valve element, in particular the valve body, at any time without the valve being influenced by external forces. In addition, the position measuring sensor can be used to adapt the valve control system with regard to changes in the operating points, so that increased forces on the valve can be avoided. This means that the position measuring sensor can directly generate information about the travel of the valve stem, and the necessary travel of the valve stem when opening and closing the valve can be recorded and monitored regardless of the ambient conditions.

[0049] Furthermore, the valve stem can be provided in a valve housing part which has cooling fins, particularly preferably on an outer circumferential surface of the housing.

[0050] With such a design, it is possible to reduce the axial forces of thermal expansion caused, for example, by steam flow in the valve, since heat can be dissipated from the valve through the cooling fins.

[0051] This can reduce changes in the valve's operating points and ensure easy positioning and less wear due to less load on the valve.

[0052] Furthermore, according to one aspect, the valve housing has a first and a second connection in order to be able to establish a connection to the pipeline. SHORT DESCRIPTIONS OF THE DRAWINGS

[0053] A valve for controlling or regulating a fluid flow, in particular a steam flow, is explained below using schematic drawings according to an exemplary embodiment. General examples of such devices are used, for example, in steam circuits of power plants, in particular as an injection valve of a steam turbine or in connection with the operation of a steam engine. They show: Figure 1 : a schematic cross-sectional view of the valve according to an exemplary embodiment, which is not part of the present invention, in an overall structure with an externally arranged drive and with a holder provided for these elements; Figure 2 : a schematic cross-sectional view of the valve from Fig. 1 ; Figure 3 : an enlarged partial cross-sectional view of area A from Fig. 2 . Figure 4: a spherical valve body on a rectangular valve seat according to another embodiment. Figure 5 : a schematic cross-sectional view of the valve according to a further embodiment, in which the valve drive interacts directly with the valve body to transmit force and the two elements are movable independently of each other. Figure 6 : a schematic cross-sectional view of the valve according to yet another embodiment, in which the valve train interacts directly with the valve body to transmit force and the two elements are movable independently of each other. Figure 7 : a cross-sectional view of the Figure 6 shown valve body with longitudinal grooves. DESCRIPTION OF THE PREFERRED EMBODIMENT

[0054] Figure 1shows the overall structure of a valve with an externally arranged drive and with a holder 53 provided for these elements. The valve arranged on the holder 53 is configured by a valve member 20, a valve train 30, which, similar to a spindle, has an external thread on its outer circumferential surface, and a damper 40 arranged between the valve member 20 and the valve train 30, the elements of which will be described in more detail later. Furthermore, an inductive proximity sensor 60 is provided on the holder 53 above the valve train 30, via which an axial movement of the valve train 30 is determined and which is connected to a controller. The controller serves to control and / or regulate the valve, in particular the movement of the valve member.

[0055] In addition, a drive 50 is connected to the holder 53. The drive 50 can be designed as a stepper motor. Furthermore, a chain wheel 51 is provided on the power-transmitting output of the drive 50. This chain wheel 51 is power-transmitting with the Fig. 2 The drive belt 10 is connected to the sprocket 31 shown, so that a rotational force can be transmitted. In the exemplary embodiment, which is not part of the present invention, this connection is made by means of a chain (not shown), e.g., a stainless steel chain, which allows for continuous and precise power transmission because slippage, as with a belt connection, is avoided. However, a toothed belt would also be conceivable as an alternative to the chain.

[0056] The Figure 2The valve shown has a conical valve seat 10. The valve seat 10 is formed in a first valve housing part 12 with an inlet 11 and a non-visible outlet, so that a fluid flow can flow from the inlet 11 via the valve seat to the outlet (not shown) in the first valve housing 12 when the valve is arranged in a pipeline (not shown) when the valve is closed. When the valve is closed, a valve body 22 of the valve rests against the valve seat 10 in such a way that it completely blocks the fluid flow from the inlet 11 to the outlet in the first valve housing.

[0057] The valve body 22 is formed with the valve stem 21, in particular in one piece and of the same material. Consequently, the valve body 22 and the valve stem 21 together form the Figure 1 described valve member 20.

[0058] The valve stem 21 is mounted in the valve housing part 12 in an axial direction (longitudinal direction) of the valve stem 21. For this purpose, a plurality of stuffing boxes 14 are provided. The stuffing boxes 14 rest against an axially lower end (facing the valve seat 10) of a radial recess in the first valve housing part 12, and their position is defined in the axial direction by the limiting element 15. Furthermore, the limiting element 15 is fixed in its axial and radial position by a connection to the first valve housing part 12.

[0059] Furthermore, cooling fins 13 are provided on an outer peripheral surface of the first valve housing part 12.

[0060] The first valve housing part 12 forms the valve housing together with the second valve housing part 36, which is formed axially above the first valve housing part 12 and connected to the first valve housing part 12. The second valve housing part 36 and the first valve housing part 12 are connected in such a way that the limiting element 15 extends through the second valve housing part 36 into the first valve housing 12.

[0061] Furthermore, the valve stem 21 of the valve member 20 projects in the axial direction from the first valve housing part 12 and the limiting element 15 into the second valve housing part 36.

[0062] At an upper end (the end facing away from the valve seat 10) of the second valve housing part 36, a sprocket 31 is rotatably mounted radially on the second valve housing 36 via a radial projection by means of a bearing element 33. The bearing element 33 can be designed either as a plain bearing or as a rolling bearing. On the axially other side of the radial projection of the sprocket 31, the sprocket 31 is secured in its bearing by a cover 32, thus preventing the bearing of the sprocket 31 from falling apart and enabling the problem-free application of radial forces. This makes it possible to prevent damage to the valve itself or, in particular, to the proximity sensor 60 arranged above the valve.

[0063] The sprocket 31 is fixedly connected to a rotating spindle 34, which is cylindrical in the axial direction. This means that an outer cylindrical circumferential surface of the rotating spindle 34 is fixedly connected to the sprocket 31. The inner circumferential surface of the rotating spindle 34 has an internal thread in the axial direction, which is dimensioned such that these threads of the rotating spindle 34 engage with the external thread of the valve train 30 and thus guide the valve train 30 centrally along an axial direction. This means that the axial position of the valve train 30 can be defined by means of a relative movement via the threads between the valve train 30 and the rotating spindle 34. Thus, a rotational force of the sprocket 31 is converted via the rotating spindle 34 into a purely translational force in the axial direction of the valve train 30. It should therefore be noted that the valve train 30 does not rotate with the sprocket 31.

[0064] At an axially upper end of the valve train 30, in the exemplary embodiment, which is not part of the present invention, Figure 2 In addition, a test plate 35, which interacts with the proximity sensor 60, is provided for checking the axial travel of the valve train. This means that the test plate serves to Figure 1 explained proximity sensor 60 to check an axial movement of the valve train 30.

[0065] Furthermore, in the exemplary embodiment, which is not part of the present invention, a damper 40 is arranged between the valve train 30 and the valve member 20 (see in particular Fig. 3). The arrangement of the damper 40 in the axial direction between the valve train 30 and the valve stem 21 makes it possible to compensate for forces generated by thermal expansion, e.g., of the valve member, so that the rotation of the rotary spindle 34 or the sprocket 31 is not subjected to axial forces. Furthermore, the damper 40 can dampen forces transmitted from the valve train 30 to the valve stem 21.

[0066] In the Figures 1 to 3In the exemplary embodiment shown, which is not part of the present invention, the damper 40 is provided in a pot construction. This means that the damper 40, in this case a coil spring, is formed between a cover 42 and a pot 41. In this case, the cover 42 is firmly connected to the end of the valve train 30 facing the damper 40, for example via a tongue and groove connection. Likewise, the pot 41 can be firmly connected to the end of the valve stem 21 facing the damper 40 via a tongue and groove connection. A positive connection between the pot 41 or the cover 42 and the ends of the valve train 30 or the valve stem 21 is also conceivable. Furthermore, the cover 42 is designed such that it surrounds one end of the damper 40 in the circumferential direction and can be axially guided on the inner circumferential side surfaces of the pot 41.This prevents non-axial displacement of the damper and enables a dynamic valve seat, which simplifies positioning and reduces forces acting on the valve seat 10.

[0067] In a further embodiment not shown, which is not part of the present invention, it is possible for both the end of the damper 40 facing the valve stem and the valve train to be guided in the axial direction with a piston-like structure, and for the damper to rest only on the axial ends of the valve stem and the valve member, while non-axial movement is prevented by the design of the piston-like structures on the valve train 30 and valve stem 21. In this case, the piston-like structure is designed with axial projections at the radial ends in the axial direction of the damper 40, which limit non-axial movement of the damper.

[0068] In a further embodiment not shown, which is not part of the present invention, it is possible for both the cover 42 and the pot 41 to be rigidly connected to the damper 40. In a further embodiment not shown, which is not part of the present invention, it is also possible for the coil spring 40 to be rigidly connected to the valve train 30 and the valve stem 20. In this case, the conversion of the rotary movement into axial movement, as described above, takes place in the region of the rotary spindle 34 and the threads of the valve train 30.

[0069] In a further embodiment not shown, which is not part of the present invention, it is also possible for the coil spring 40 to rest only on the mutually facing ends of the pot 41 and the cover 42, and for the pot 41 to be arranged between the valve stem 21 and the valve train 30 for axially guiding the damper. In this case, the cover can move in the axial direction, as in the described exemplary embodiment, which is not part of the present invention, and thus transmit forces to the damper 40 and thus to the valve member 20.

[0070] In a further embodiment not shown, the speed and the size of the valve movement between a closed and an open state, i.e. the so-called valve lift, can be controlled not only by the speed or the steps of the drive 50, but also by the pitch of the threads on the valve train 30.

[0071] In another in Figure 4 In the schematically illustrated embodiment of the present invention, it is possible for the valve body 22 to have a spherical section. This means that when the spherical valve body 22 comes into contact with the valve seat 10, the valve member 20 is automatically centered by the spherical shape of the valve body 22. This has the effect that the spherical design of the valve body 22 enables a uniform force distribution on the valve body 22 and valve seat 10 and simple positioning. In the further Figure 4In the embodiment shown, the spherical portion of the valve body 22 rests on a rectangular valve seat 10 in the form of a bore. This means that the valve seat 10 is a hole in the first valve housing part 12 against which the spherical portion of the valve body 22 rests via a line contact. This means that closure of the valve can be ensured despite dynamic operating points via the line contact and automatic centering in this embodiment.

[0072] In the following, the function of the valve for controlling and / or regulating a fluid flow will be described in more detail with the help of the Figure 2 and 3 be explained.

[0073] The valve of the exemplary embodiment, which is not part of the present invention, serves to guide a fluid flow in the open state of the valve from the inlet 11 in the first valve housing part 12 through the region of the valve seat 10 to the outlet (not shown) in the first valve housing part 12. In a closed state of the valve, the valve body 22 of the valve member 20 presses in the axial direction against the valve seat 10 in the first valve housing part 12 and thus blocks the fluid flow from the inlet 11 to the outlet. This means that in order to switch a valve between an open and a closed state of the valve and thus enable control or regulation of a fluid flow, it is necessary to lift the valve body 22 off the valve seat 10 in the axial direction or to press the valve body 22 into the valve seat 10. This requires an axial movement of the valve member 20.

[0074] Generally, in the present embodiment, which is not part of the present invention, a rotational force generated by the drive 50 is converted into an axial force by means of a force transmission from the rotary spindle 34 to the threads of the valve train 30, which is then transmitted to the valve member 20 via the damper 40. The design of the rotary spindle 34, together with the above-described threads of the valve train 30, thus represents a threaded spindle that can convert a rotational movement into an axial movement.

[0075] The valve closing process is thus structured, for example, as follows: First, the drive 50 is actuated by means of a control system so that it generates a rotational force in one direction. This rotational force can be transmitted, if necessary with a transmission ratio, from the sprocket 51 to the sprocket 31 via, for example, a chain connection. This causes the sprocket 31, which is mounted in the second valve housing part 36, to rotate, which also causes the rotating spindle 34, which is firmly connected to the sprocket 31, to rotate. The rotation of the rotating spindle 34 and its threads, which engage with the external thread of the valve train 30, exerts an axial force on the valve train 30, causing the valve train 30 to move purely translationally in the direction of the valve seat 10 (here downwards). If the direction of rotation of the drive 50 is reversed, the valve train 30 moves in the axial direction away from the valve seat (here upwards) due to the rotating spindle 34.During the closing process, the axial movement of the valve train 30 in the direction of the valve seat is transmitted via the damper 40 to the valve member 20, so that in the present example of the closing process, the valve member 20 also moves downward in an axial direction until the valve body 22 of the valve member 20 comes into contact with the valve seat 10, thereby blocking flow through the valve. Upon further downward movement of the valve train 30, the damper 40 is compressed, and the damper 40 enables the valve body 22 to be pressed into the valve seat 10 with a virtually constant force, regardless of the movement of the drive 50 or the steps of the drive 50.

[0076] As described above, during a valve opening process, the direction of rotation of the drive 50 is reversed, so that the sprockets 31 and 51 rotate in opposite directions. This moves the valve train 30 axially away from the valve seat 10. This first relieves the pressure on the damper 40 before the valve body 22 is lifted from the valve seat 10 and the flow begins.

[0077] Furthermore, it is possible for the drive 50 to be controlled via sensors in addition to the predefined travel paths of the valve train 30 by the rotary spindle 34 and the drive 50. According to the exemplary embodiment, which is not part of the present invention, an axial travel path of the valve train 30 can be monitored by a contactless measuring system, for example, via the proximity sensor 60 and the interacting test plate 35 on the valve train 30. In this case, it is desirable that, in addition to the pure travel path for the interaction of the valve body 22 with the valve seat 10, an additional axial travel path is also traveled, which compresses the damper 40.

[0078] A measuring system that directly measures the travel of the valve member 20 is also possible. The travel of the valve member 20 can thus be used as a control variable for the actuator 50.

[0079] An embodiment of the valve according to the present invention will now be described. Figure 5 a schematic cross-sectional view of the valve according to a further embodiment, in which the valve drive interacts directly with the valve body to transmit force and the two elements are movable independently of one another.

[0080] Similar to the embodiment described above, which is not part of the present invention, the further embodiment also comprises a valve housing with an inlet and an outlet, a valve train 30, a valve body 22, and a valve stem 21. Similar to the exemplary embodiment described above, the valve stem 21 and the valve body 22 form the valve member 20. In this embodiment, too, the valve body 22 is provided to come into contact with a valve seat 10 to block fluid flow.

[0081] The Figure 5 The embodiment shown differs from the exemplary embodiment of the Figures 1-4 , which is not part of the present invention, in that the valve body 22 and the valve train 30 are not ("fixedly") connected, but are movable independently of each other.

[0082] In the illustrated embodiment, the valve body 22 is a ball 23. The ball 23 is accommodated in a convex-shaped receptacle 39 and mounted therein for free movement. This allows free rotation of the spherical valve body 22 and secure closure of the valve. The receptacle 39 is provided at a first axial end of a valve stem 21. A spring element 70 engages an opposite second axial end of the valve stem 21. The spring element 70 presses the ball 23 axially into the valve seat 10.

[0083] The valve body 22 is consequently pressed into the valve seat 10 both by the fluid pressure generated during operation by the fluid flowing in the valve and by the spring element 70.

[0084] Furthermore, the Figure 5 shown embodiment of the exemplary embodiment of the Figures 1-4 in that the valve train 30 can be positioned at a distance from and decoupled (unconnected) from the valve body 22 when the valve is closed, and can press directly onto the valve body 22 by means of the axially movable shaft 38 when the valve is opening. This means that the valve train 30 and the valve member 20, or the valve body 22, are movable independently of one another, and the valve train 30 and the valve body 22 are decoupled or not connected to one another.

[0085] In the following we will briefly look at the function of the valve according to the Figure 5shown embodiment.

[0086] The fluid flowing into the valve housing, for example in the form of steam, and the predefined spring force of the spring element 70 applied to the valve body 22 force the spherical valve body 22 into the valve seat 10 when the valve is closed. This blocks the flow of fluid through the valve body 22 and closes the valve. In this state, the valve train 30, in particular the axially movable shaft 38 of the valve train 30, is spaced from the valve body 22, so that no thermal stresses can occur between the two elements.

[0087] When the valve is to be (partially) opened, the valve train 30 is operated similarly to the exemplary embodiment of the Figures 1-4, which is not part of the present invention, is driven by the motor and thus moves in the axial direction opposite to the direction of the spring force of the spring element 70 and towards the valve body 22.

[0088] When the valve train 30 comes into contact with the valve body 22, the degree of opening can be controlled by further moving the valve train 30 against the direction of the spring element 70 and against the flow of the fluid from the inlet to the outlet of the valve housing. That is, in the Figure 5 In the further embodiment shown, the valve train 30, in particular the axially movable shaft 38 of the valve train 30, presses against the valve body 22 and lifts the valve body 22 from the valve seat 10 against the spring force of the spring element 70 and the fluid pressure. Thus, the valve can be opened.

[0089] When the valve is closed again, the travel path of the axially movable shaft 38 of the valve train 30 is reversed, and the valve body 22 is repositioned in the valve seat 10 due to the spring force of the spring element 70 and the pressure of the fluid on the valve body 22. Consequently, the valve train 30 no longer needs to be in contact with the valve body 22 in order to correctly position the valve body 22 and close the valve.

[0090] In this way, a functional separation, i.e. a decoupling, of the axial movement and the sealing of the fluid flow can be realized and problems described above, such as distortion, tension or wedging of the valve, can be prevented.

[0091] Also in the Figure 5In the embodiment shown, a proximity sensor can be provided in the area of ​​the valve train 30, so that position monitoring of the valve train 30 can be ensured. This serves primarily for sensory comparison with the control of the engine 50. Thus, problems in the valve can be detected quickly and easily.

[0092] A further embodiment is described with reference to Figure 6 described. Also Figure 6 shows a schematic cross-sectional view of the valve, in which the valve train interacts directly with the valve body to transmit force and the two elements can be moved independently of each other.

[0093] Here, the Figure 6 shown embodiment differs from the previously described embodiments of the Figures 1 to 4 which are not part of the present invention, and in particular from the Figure 5shown embodiment, that the valve body 22 and the valve train 30 are not ("fixedly") connected, but are movable independently of each other, and that the valve body 22 is conical in the radial direction.

[0094] In the Figure 6 In the embodiment shown, the valve stem 21 and the valve body 22 are designed as an integral component. However, multi-piece designs consisting of the valve body 22 and the valve stem 21 are also conceivable, so that here too the valve stem 21 and the valve body 22 form the valve member 20. Furthermore, in this embodiment, the valve body 22 is also provided to come into contact with a valve seat 10 in order to block fluid flow.

[0095] Also in the Figure 6 illustrated embodiment is similar to that in Figure 5, a spring element 70 is provided to press the valve body 22 in the axial direction into the valve seat 10. However, in such an arrangement, the largest part of the closing force of the valve body 22 against the valve seat 10 is achieved by means of the steam pressure, and the spring element 70 contributes to this as a guide and support element.

[0096] Thus, similar to the one in Figure 5 In the embodiment shown, the valve train 30 is positioned at a distance and decoupled (unconnected) from the valve body 22 in the closed state of the valve and can press directly onto the valve body 22 by means of the axially movable shaft 38 during the opening process of the valve.

[0097] Here, the valve body 22 of the Figure 6shown embodiment has a centrally arranged, conical projection 24 which extends in the axial direction in the direction of the valve train 30, wherein the diameter of the projection 24 decreases in the direction of the valve train 30.

[0098] When opening the valve according to the Figure 6 In the embodiment shown, the axially movable shaft 38 comes into contact with the projection 24 and thus opens the valve against the spring force of the spring element 70 and against the fluid back pressure. Due to the conicity of the projection, automatic self-centering with the flow fluid at the valve seat can occur when the valve closes, thus improving the sealing performance and long-term durability of the valve.

[0099] In addition, the Figure 6The valve body 22 shown has a surface (25) that is beveled in the axial direction in the contact area with the valve seat. The angle of inclination of the upper valve seat surface to the horizontal in the embodiment shown is 1°. However, other angles between 0.5° and 1.5° for self-centering of the valve body 22 on the valve seat 10 are also possible.

[0100] In this way, surface contacts, which are more difficult to seal, can be prevented and, according to the Figure 6 In the embodiment shown, there is a line contact between the valve seat 10 and the valve body 22 and thus an improved and easier sealing or shut-off of the valve.

[0101] Figure 7 also shows a cross-sectional view through the Figure 6 integrally formed valve body 22.

[0102] In Figure 7longitudinal grooves 26, in particular six longitudinal grooves 26, are formed uniformly along the axial extension direction of the integral valve body 22 on the outer peripheral surface thereof.

[0103] The longitudinal grooves 26 on the valve body 22 allow the steam flowing through the valve to flow particularly easily and quickly within the valve. Although the longitudinal grooves 26 are shown on the integral valve body 22, the longitudinal grooves 26 can also be formed on the valve stem 21 of the remaining embodiments to allow the steam to flow quickly and easily through the valve along the valve body guide, e.g., along the valve stem 21. LIST OF REFERENCE SYMBOLS

[0104] 10: Valve seat 11: Inlet 12: First valve housing part 13: Cooling fin 14: Stuffing box 15: Limiting element 20: Valve member 21: Valve stem 22: Valve body 23: Ball 24: Projection 25: Bevelled surface of the valve body 26: Longitudinal groove 30: Valve gear 31: Rotating spindle 32: Cover 33: Bearing element 34: Rotating spindle 35: Test plate 36: Second valve housing part 38: Axially movable shaft 39: Convex shaped holder 40: Damper (coil spring) 41: Pot 42: Cover 50: Drive 51: Chain wheel 53: Bracket 70: Spring element

Claims

1. Valve for controlling and / or regulating a steam flow, comprising: a valve seat (10); a valve body (22); and a valve drive (30) which, for axial movement of the valve body (22), interacts with the valve body (22) in a force-transmitting manner in order to lift the valve body (22) from the valve seat (10), wherein the valve drive (30) and the valve body (22) are decoupled, the valve body (22) is pressed into the valve seat (10) by means of a spring element (70) and, for axial movement of the valve body (22), the valve drive (30) interacts with the valve body (22) in a force-transmitting manner in order to lift the valve body (22) from the valve seat (10), the valve drive (30) and the valve body (22) can be moved independently of each other, and the valve drive (30) is spaced apart from the valve body (22) when the valve is closed and comes into contact with the valve body (22) to lift the valve body (22) from the valve seat (10).

2. Valve according to claim 1, wherein the spring force of the spring element (70) presses the valve body (22) into the valve seat (10) in a first direction and the valve drive (30) can be moved in an opposite second direction to lift the valve body (22) from the valve seat (10).

3. Valve according to one of the preceding claims, wherein a proximity sensor (60) is provided to detect the axial movement of the valve drive (30).

4. Valve according to one of the preceding claims, wherein the valve body (22) has at least one spherical section which interacts with the valve seat (10) in a closed position of the valve in which the valve body (22) is pressed into the valve seat (10).

5. Valve according to claim 4, wherein the valve body (22) is a sphere.

6. Valve according to claim 5, wherein the valve body (22) is accommodated in a freely movable manner in a convexly shaped receptacle (39).

7. Valve according to one of the claims 1 to 3, wherein the axial end of the valve body (22) facing the valve drive (30) has a surface (25) bevelled towards the central axis of the valve body (22) which forms a depression on the valve body (22), wherein the angle of inclination of the bevelled surface (25) of the valve body (22) to a horizontal is between 0.5° and 1.5°.

8. Valve according to one of the preceding claims, wherein the valve seat (10) is of rectangular design in the axial longitudinal section.

9. Valve according to one of the preceding claims, wherein the valve is designed in such a way that the valve body (22) is pressed into the valve seat (10) by means of the spring element (70) and the steam pressure.