Overpressure safety valve

Abstract

The invention relates to an overpressure safety valve, which is designed to open upon exceeding a maximum pressure value and for this purpose has a valve element (10), which is movable along a valve axis (x), with a pressure side (28) and an outlet side (30) which faces away from the pressure side (28) in the direction of the valve axis (x), wherein the valve element (10) is connected on its outlet side (30) to at least one resistance element (32), which is spaced apart from the valve element (10) and is situated on the outlet side of the valve element (10) in a flow path.

Description

Description

[0001] The invention relates to an overpressure safety valve which is designed to open when a maximum pressure value is exceeded.

[0002] Such pressure relief valves are used in machines and industrial plants to release the medium in the system, such as gas or steam, in a controlled manner via the safety valve and reduce the pressure in the event of excessive pressure in a piping and / or container system. Spring-loaded valves are known for this purpose; a maximum pressure value is predetermined by the spring force. The problem with these valves is their behavior upon opening, as pressure changes occur on both the pressure side and the outlet side when the valve opens, which can lead to oscillation of the valve element, making rapid, controlled pressure reduction difficult.

[0003] The object of the invention is to improve an overpressure safety valve in such a way that it has a more stable behavior when opening.

[0004] This object is achieved by an overpressure safety valve having the features specified in claim 1. Preferred embodiments emerge from the subclaims, the following description, and the accompanying figures.

[0005] The overpressure safety valve according to the invention is designed to open when a maximum pressure value on a pressure side of the safety valve is exceeded. For this purpose, the overpressure safety valve has a valve element that is movable along a valve axis and has a pressure side and an outlet side facing away from the pressure side in the direction of the valve axis. The pressure acting on the pressure side of the valve element causes the valve element to open when the maximum pressure value is exceeded, whereby the medium can then flow around the opened valve element and is discharged on the outlet side. According to the invention, the valve element is connected on its outlet side to at least one resistance element. This is arranged such that it is spaced from the valve element, in particular its outlet side. Furthermore, the resistance element is located in a flow path on the output side, i.e. on the outlet side of the valve element.The resistance element thus forms at least one surface upon which a fluid flow can act, flowing past the valve element when the valve element is in its open position. The flow acting on the resistance element thus generates a force acting on the resistance element. Since the resistance element is connected to the valve element, the force also acts on the valve element and can thus contribute to minimizing its undesirable vibration behavior. Particularly preferably, the resistance element is arranged such that the flow generates a force acting on the resistance element in the opening direction of the valve element, which thus supports the opening process of the valve element and prevents undesirable closing due to vibrations that occur.Because the resistance element on the outlet side of the valve element is spaced apart from the valve element, the resistance element is subjected to force by the outgoing flow with a time delay. This results in a slight phase shift between the forces, which stabilizes the opening. behavior, especially helping to avoid unwanted vibrations.

[0006] The resistance element thus forms a structure located in the flow path on the outlet side of the valve element, which comes into contact with the escaping fluid flow and is designed such that the fluid flow acts on the structure, so that a stabilizing force, preferably one that reduces vibration, is generated on the valve element via the structure. By appropriately designing the structure, i.e., the at least one resistance element, the magnitude and direction of the forces generated by the fluid flow on the valve element can be adjusted to ensure the desired behavior of the valve element during opening.

[0007] The at least one resistance element can be disc-shaped. For example, the resistance element can protrude radially from a shaft that supports the valve element, as described in more detail below, so that the disc-shaped resistance element forms a projection onto which a fluid flow or fluid pressure can act. The disc-shaped resistance element can be flat with parallel surfaces, but also with curved or angled surfaces.

[0008] According to a possible embodiment, the at least one resistance element has at least one surface extending at an angle, preferably transversely and more preferably perpendicularly to the valve axis. This surface can more preferably extend substantially parallel to the pressure side of the valve element. By adapting the surface of the resistance element, the force acting on the resistance element can be optimized such that a desired additional force and a desired vibration behavior of the system, consisting of resistance element and valve element, can be realized, or unwanted vibrations can be prevented as best as possible.

[0009] According to a further possible embodiment, the resistance element can have an angled wall or a collar on the outer circumference of at least one surface, preferably on a surface facing the valve element. For example, the resistance element can also be pot-shaped, wherein the angled wall can form an annular, particularly preferably cylindrical collar, which is preferably directed towards the valve seat. The collar creates a circumferentially limited space below the resistance element, i.e. on the side of the valve element facing the valve element, in which space a dynamic pressure can develop, which exerts a force on the resistance element.

[0010] According to a further possible embodiment of the invention, a free space is formed in the circumferential region of the valve element, preferably also in the circumferential region of the at least one resistance element. The free space is preferably an annular free space between the outer circumference of the valve element and / or the outer circumference of the at least one resistance element and a surrounding housing part. The free space allows the exiting flow to flow past the valve element to the resistance element. Furthermore, if a free space is formed in the circumferential region of the resistance element, the flow can also flow around the resistance element in order to act on both sides of the resistance element and / or also to act on subsequent resistance elements, in the event that several resistance elements are arranged one behind the other.

[0011] The radial extension of the resistance element relative to the valve axis X can be greater or smaller than the axial extension of the valve element. It is possible for the radial extension of the resistance element to be smaller or larger than the radial extension of the valve element over its entire circumference. However, it is also conceivable for the resistance element to project radially beyond the extension of the valve element in individual circumferential regions and / or to have a smaller radial extension than the valve element only in individual circumferential regions.

[0012] The valve element is preferably designed as a valve disk, the pressure side of which can form a sealing contact with a valve seat. The valve seat is preferably an annular contact surface or contact edge that surrounds a pressure line or pressure area. This pressure area is closed by the valve element resting against the valve seat. The fluid pressure within the pressure area exerts a force on the valve element, which, when the predefined maximum pressure value is exceeded, lifts the valve element from the valve seat, thus opening the safety valve.

[0013] According to a further preferred embodiment, the valve element can be pot-shaped with an annular wall surrounding the valve seat, or a collar surrounding the valve seat. This means that the valve element can be designed as a valve disk resting against an annular valve seat, with an annular wall or a collar protruding from the valve disk toward the valve seat in such a way that it circumferentially surrounds the valve seat. The annular wall or collar can extend parallel to the valve axis or at an angle to the valve axis.

[0014] The valve element is preferably spring-loaded and is moved by the spring preload into a position adjacent to the valve seat. tion. The spring preload is adjusted so that the force exerted by the spring preload on the valve element defines the specified maximum pressure value, above which the valve element lifts off the valve seat. The spring preload can be applied in a known manner, for example, by a coil spring, whereby the spring force can be preset by changing the compression of the spring.

[0015] According to one embodiment of the invention, the valve element has on its outlet side a shaft extending in the direction of the valve axis, which shaft carries the at least one resistance element. This means that the resistance element is attached to the shaft and / or formed integrally with it. The shaft can, for example, be attached to the valve element or formed integrally with it. A multi-piece shaft construction or another suitable connecting structure between the valve and resistance element is also possible. The shaft can simultaneously serve to guide the valve element in its direction of movement along the valve axis. The shaft or a connecting structure serves to transmit force from the resistance element to the valve element, so that the forces acting on the resistance element are transferred to the valve element or the resistance element forms a common system with the valve element.

[0016] According to a further possible embodiment, the at least one resistance element can have at least one surface extending obliquely to the valve axis. Two surfaces facing away from each other in the direction of the valve axis can extend obliquely, whereby the surfaces can extend parallel or at an angle to each other. It is also conceivable for one surface to extend substantially normal to the valve axis and the other surface to extend obliquely to the valve axis. The surfaces can also The surfaces can be angled and / or corrugated. The design of the surfaces allows for further optimization of the force application surfaces in a desired manner, in order to influence the opening behavior of the valve element in a defined manner.

[0017] It is also possible for the at least one resistance element to have at least one curved surface. This also allows the effective areas to be adjusted as desired. Furthermore, inclined and curved surfaces can be used to reduce the flow resistance, if desired, or to influence it in a desired manner.

[0018] According to a further possible embodiment, the at least one resistance element can taper outward in a direction radial to the valve axis. This can be achieved, for example, by having two opposing surfaces of the valve element extend at an angle to the valve axis or by being curved in a suitable manner.

[0019] The at least one resistance element can be designed or arranged symmetrically to the valve axis. Alternatively, it is possible for the at least one resistance element to be designed asymmetrically to the valve axis, preferably projecting further in a first circumferential region in the radial direction with respect to the valve axis than in a second circumferential region. Such asymmetry can, for example, be achieved by adapting to the surrounding housing geometry of the valve housing. The valve housing may also be designed asymmetrically, in particular if an outlet line is connected in a direction radial to the valve axis. The asymmetric design of the resistance element can be adapted to the shape of the valve housing in such a way that a fluid flow in the valve housing optimally applies force to the resistance element.

[0020] According to the invention, at least one resistance element is arranged. However, it is possible to arrange several resistance elements one behind the other in the direction of the valve axis and at a distance from one another. The several resistance elements can be identical or different, preferably in one of the above-mentioned configurations. According to a particular embodiment of the invention, several resistance elements, for example two or three resistance elements, can be arranged at a distance from one another, each of which is disc-shaped and has a protruding collar on the outer circumference of its surface facing the valve element. If several resistance elements are provided, several resistance elements do not each have to extend completely around the valve axis.Rather, it is also possible for several resistance elements to be arranged one behind the other and spaced apart from one another in at least one circumferential region relative to the valve axis, while only one resistance element is arranged in another circumferential region. An offset arrangement is also conceivable. An asymmetry allows, for example, adaptation to the surrounding valve housing, so that the fluid flow guided through the valve housing can act on the resistance element in the desired manner and exert the desired forces on the system consisting of the valve element and resistance elements.

[0021] According to a further possible embodiment of the invention, a cylinder wall can be arranged on the outlet side of the valve element at a distance from the valve seat in such a way that at least when the valve is opened, a resistance element enters a space surrounded by the cylinder wall. Particularly preferably, the The resistance element forms a piston-cylinder arrangement with the cylinder wall, in which the fluid pressure acts primarily on one side of the resistance element, namely the side facing the valve seat. The second, remote side of the valve element then faces an interior space enclosed by the cylinder wall, in which a lower pressure preferably prevails, so that an additional opening force can be exerted on the valve element by applying pressure to the resistance element from one side.

[0022] The invention is described below by way of example with reference to the accompanying figures, which show: Figure 1 schematically shows an overpressure safety valve according to the invention, Figure 2 schematically shows a possible design of at least one resistance element, Figure 3 shows another possible design of the resistance elements, Figure 4 shows another possible design of the resistance elements, Figure 5 shows a further example of the design of at least one resistance element, Figure 6 shows a further example of the design of at least one resistance element, Figure 7 shows a further example of the design of at least one resistance element, Figure 8 shows a further example of the design of at least one resistance element, Figure 9 shows a further example of the design of at least one resistance element, Figure 10 shows a further example of the design of at least one resistance element, Figure 1 1 shows a further example of the design of at least one resistance element, Figure 12 shows another possible design of the resistance elements, Figure 13 shows another possible design of the resistance elements, Figure 14 shows another possible design of the resistance elements, Figure 15 is a schematic plan view of another possible arrangement of at least one resistance element, and Figure 16 is a schematic plan view of another possible arrangement of at least one resistance element, and Figure 17 schematically enlarges a valve element with a resistance element as shown in Figure 1.

[0023] Figure 1 schematically shows the overall structure of an overpressure safety valve according to the invention, which essentially corresponds to a conventional structure of an overpressure safety valve. The valve housing 2 has a pressure port 4 and a discharge port 6. The overpressure safety valve is connected to a pressure line or a pressure vessel via the pressure port 4. A discharge line, a discharge vessel, or the like can be connected to the discharge port 6. Inside the valve housing 2, adjacent to the pressure port 4, there is an annular valve seat 8, against which a plate-shaped valve element 10 is held in sealing contact. The valve element 10 has a circumferential collar 12 that surrounds the valve seat 8. A shaft 14 is attached to the valve element 10 and is guided in a guide plate 16 for linear movement in the direction of the valve axis x.A first contact plate 18 is attached to the shaft 14 so that it can move together with the shaft 14 along the valve axis x. A second contact plate 20 is supported via a threaded sleeve 22 on the spring housing 24, which is connected to the valve housing 2. A compression spring 26 in the form of a helical spring is arranged between the contact plates 18 and 20. By adjusting the threaded sleeve 22, the compression of the compression spring 26 can be varied in order to set the opening pressure, i.e., the maximum pressure value above which the pressure relief valve should open. The fluid pressure inside the pressure port 4 presses against the pressure side 28 of the valve element 10. If the force exerted by this pressure on the valve element 10 exceeds the force generated by the compression spring 26, the valve element 10 lifts off the valve seat 8 and the fluid can flow from the pressure port 4 into the discharge port 6.

[0024] After the valve element 10 is lifted off the valve seat 8, the pressure conditions in the area surrounding the valve element 10 change. The pressure in the pressure port 4 decreases, while the pressure in the outlet port 6 and in particular on the outlet side 30 of the valve element 10 increases. This can lead to an unstable opening state in which the valve element 10 oscillates in an undesirable manner. In order to minimize such undesirable oscillation and stabilize the opening process, an additional structure in the form of a resistance element 32 is arranged on the valve element, spaced from the outlet side in the direction of the valve axis x, in the flow path. The resistance element 32 is attached to the shaft 14 and / or directly to the valve element 10, such that it is spaced from the outlet side 30 of the valve element 10.In this example, the resistance element 32 is disc-shaped and has two surfaces extending transversely to the valve axis x. The resistance element 32 has, on its surface facing the valve element 10, an angled wall 33 on the outer circumference of this surface, which forms a cylindrical collar that extends essentially concentrically to the valve axis X. In this way, a space is created below the resistance element 32, circumferentially delimited by the angled wall 33, in which a back pressure can build up. This special embodiment is shown in detail again in Figure 17. The resistance element 32 is located inside the valve housing 2 in the flow path through which a fluid flow flows, exiting between the valve seat 8 and the valve element 10.In this exemplary embodiment, the valve element 10 and the resistance element 32 are circumferentially surrounded by a free space through which a fluid flow can occur. Such a fluid flow flows around the valve element 10 and will thus act in particular on the surface of the resistance element 32 facing the outlet side 30, so that this flow exerts a force on the shaft 14 and via the resistance element 32. thus exerted by the entire system consisting of valve element 10 and resistance element 32. This force helps stabilize the opening process and reduce unwanted vibrations. The resistance element 32 is spaced apart from the valve element 10 in the direction of the valve axis X. Thus, the force applied to the resistance element 32 when the valve opens occurs with a time delay compared to the force applied to the valve element 10, so that a phase shift can occur, which can prevent excessive vibration in the system.

[0025] Such a resistance element 32 or several such resistance elements 32 can be configured in a variety of ways. Figures 2 to 16 schematically show possible configurations of one or more resistance elements, although this is not intended to be an exhaustive list.

[0026] Figure 2 essentially shows the design as described with reference to Figure 1. In the design according to Figure 3, two resistance elements 32 are arranged one behind the other and at a distance from one another. Figure 4 shows an embodiment in which three disc-shaped resistance elements 32 are arranged at a distance from one another on the outlet side 30 of the valve element 10. By arranging a plurality of disc-shaped resistance elements 32, as shown in Figures 3 and 4, a plurality of successive surfaces are created on which the fluid flow on the outlet side of the valve element 10 can act, so that overall a greater force acting on the shaft 14 in the direction of the valve axis x can be generated.

[0027] Figure 5 schematically shows a differently shaped resistance element 32a, which is conical on its side facing away from the valve element 10 and on its side facing the valve element 10. th side has a surface extending transversely to the valve axis x, as do the resistance elements 32 according to Figures 2 to 4. The surface running obliquely to the valve axis x on the side facing away from the valve element 10 can bring about better flow guidance.

[0028] In the embodiment according to Figure 6, the surface of the resistance element 32b facing the valve element 10 is also conical, ie, it runs obliquely to the valve axis x. The resistance element 32c according to Figure 7 has an overall lens-shaped shape, ie, with curved surfaces on its side facing the valve element 10 and on its side facing away from the valve element, as seen in the direction of the valve axis x.

[0029] In the embodiment according to Figure 8, the resistance element 32d is essentially plate-shaped, as in Figure 2, but has a collar 34 on its outer circumference that is angled towards the valve element 10. The collar 34 forms an angled wall which, in contrast to the collar 33 according to Figures 1 and 17, does not extend parallel to the valve axis X, but rather at an angle to it, so that the collar 34 has a conical shape. In the embodiment according to Figure 9, the resistance element 32e has a freeform with corrugated surfaces. Due to the different surface designs of the resistance elements 32 to 32e, the force application via the fluid flow can be adapted, so that overall a desired balance of the forces acting on the valve element 10 can be realized in order to stabilize the opening process of the valve element 10.

[0030] In the previously described embodiments, the resistance elements 32 are designed substantially symmetrically with respect to the valve axis x. However, it should be understood that an asymmetrical design is possible, as described below with reference to Figures 10 to 16. In the exemplary embodiment according to Figure 10, resistance elements 32f and 32g are provided which do not extend in a ring shape around the entire circumference of the valve axis x, but rather they are each arranged only on one side of the valve axis x, i.e. a limited circumferential region, and are designed, for example, in a semicircular shape. The resistance element 32f and the resistance element 32g are arranged offset from one another in the direction of the valve axis x. In Figure 11, this offset is somewhat smaller. In the exemplary embodiments according to Figures 12 and 13, two resistance elements 32f spaced apart from one another are provided on one side of the valve axis x, while only one resistance element 32g is provided on the diametrically opposite side or the opposite circumferential region.In the embodiment according to Figure 12, the resistance elements 32f are further spaced apart from one another in the axial direction x than in the embodiment according to Figure 13.

[0031] The embodiment according to Figure 14 is designed similarly to the embodiment according to Figure 13. Only the resistance element 32g is replaced by a resistance element 32h with a bulbous shape and greater axial length in the direction of the valve axis x. Figures 15 and 16 each show, in a schematic plan view, further asymmetrical designs of resistance elements 32e and 32k. In the embodiment according to Figure 15, the resistance element 32e has an elliptical shape, but is arranged essentially centered to the valve axis x. The resistance element 32k according to Figure 16 has a rectangular shape and is laterally offset to the valve axis x, i.e., arranged asymmetrically.

[0032] All the asymmetric arrangements of the resistance elements 32f to 32k according to Figures 10 and 16 allow for a better Fit to the valve housing 2 and the flow path defined thereby, which is directed toward the outlet port 6. Therefore, the flow does not run parallel to the valve axis x, but rather on the outlet side of the valve element 10 in a lateral direction toward the outlet port 6. Due to the asymmetrical arrangement of the resistance elements 32, a uniform force effect in the direction of the valve axis x can nevertheless be realized via the resistance elements 32.

[0033] It is to be understood that all the designs of resistance elements 32 to 32k, as described above, could also be realized in further modifications and in particular combinations, depending on the flow requirements and the pressures occurring. List of reference symbols 2 valve housings 4 pressure ports 6 drain nozzles 8 Valve seat 10 Valve element 12 collars 14 shaft 16 Guide plate 18 investment plates 20 investment plates 22 threaded sleeve 24 spring housings 26 compression spring 28 printed pages 30 Outlet side 32 (32, 32a-32k) resistance elements 33, 34 Angled wall, collar x valve axis

Claims

Claims 1 . Overpressure safety valve which is designed to open when a maximum pressure value is exceeded and for this purpose has a valve element (10) which is movable along a valve axis (x) and has a pressure side (28) and an outlet side (30) facing away from the pressure side (28) in the direction of the valve axis (x), characterized in that the valve element (10) is connected on its outlet side (30) to at least one resistance element (32) which is spaced apart from the valve element (10) and is located in a flow path on the outlet side of the valve element (10).

2. Overpressure safety valve according to claim 1, characterized in that the at least one resistance element (32) is disc-shaped.

3. Overpressure safety valve according to claim 1 or 2, characterized in that the at least one resistance element (32) has at least one surface extending at an angle, preferably transversely and more preferably normally to the valve axis (x).

4. Overpressure safety valve according to one of the preceding claims, characterized in that the at least one resistance element (32) has an angled wall (33; 34) on at least one surface, preferably on a surface facing the valve element (10), on the outer circumference of which.

5. Overpressure safety valve according to one of the preceding claims, characterized in that in the peripheral area of ​​the A free space is formed in the valve element (10) and preferably in the peripheral region of the at least one resistance element (32). Overpressure safety valve according to one of the preceding claims, characterized in that the valve element (10) is designed as a valve disk, which can come into sealing contact with a valve seat (8) with its pressure side (28). Overpressure safety valve according to one of the preceding claims, characterized in that the valve element (10) is pot-shaped with an annular wall (12) surrounding the valve seat (8) or with a collar surrounding the valve seat (8). Overpressure safety valve according to one of the preceding claims, characterized in that the valve element (10) is spring-biased and is forced into a position resting against the valve seat (8) by the spring preload.Overpressure safety valve according to one of the preceding claims, characterized in that the valve element (10) has, on its outlet side (30), a shaft (14) extending in the direction of the valve axis (x), which shaft carries the at least one resistance element (32). Overpressure safety valve according to one of the preceding claims, characterized in that the at least one resistance element (32) has at least one surface extending obliquely to the valve axis (x). 1 1. Overpressure safety valve according to one of the preceding claims, characterized in that the at least one resistance element (32) has at least one curved surface.

12. Overpressure safety valve according to one of the preceding claims, characterized in that the at least one resistance element (32) tapers outwards in a direction radial to the valve axis (x).

13. Overpressure safety valve according to one of the preceding claims, characterized in that at least one resistance element (32) is designed symmetrically to the valve axis (x).

14. Overpressure safety valve according to one of the preceding claims, characterized in that at least one resistance element (32) is designed asymmetrically to the valve axis (x), preferably in a first circumferential region in the radial direction with respect to the valve axis (x) projects further than in a second circumferential region.

15. Overpressure safety valve according to one of the preceding claims, characterized in that in at least one circumferential region with respect to the valve axis (x), a plurality of resistance elements (32) are arranged one behind the other and spaced apart from one another in the direction of the valve axis (x).

16. Overpressure safety valve according to one of the preceding claims, characterized in that on the outlet side of the valve element (10) a cylinder wall is arranged at a distance from the valve seat (8) in such a way that at least when opening the Valve a resistance element (32) enters a space surrounded by the cylinder wall.

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