Knife gate valve

Abstract

Knife gate valve (10) for chemical and / or petrochemical industrial plants, comprising: - a slide valve housing (11) having an inlet nozzle (12) with an outlet opening (13) and an outlet nozzle (14) with an inlet opening (15), which correspond to one another in an open position of the knife gate valve (10); - a blocking device (16) with at least one shut-off plate (17) and a pipe bridge (18) which is movably arranged between the inlet and outlet nozzles (12, 14) for opening and closing the knife gate valve (10); and - at least one guide device (19) for flow guidance, wherein the guide device (19) has at least one guide element (21) which is arranged on an inner wall (22) of the inlet nozzle (12) and reduces the outlet opening (13) of the inlet nozzle (12) in such a way that when the plate slide valve (10) is opened, an opening cross section (23) of the outlet opening (13) is enlarged at the moment of an initial, in particular first, flow entry into the pipe bridge (18), characterized in that the guide device (19) has at least one plate guide element (46) which is arranged on an inner wall of the pipe bridge (18) and extends in the flow direction.

Description

[0001] The invention relates to a knife gate valve. A knife gate valve according to the preamble of patent claim 1 is known, for example, from DE 10 2022 105 939 A1, which is attributed to the applicant.

[0002] In general, gate valves, for example, those used in coking and / or cracking processes, are subject to high demands in terms of tightness and durability. In addition to liquids or gases, the pressurized fluid conveyed through such gate valves can also contain solids, such as microparticles such as contaminants, dust, soot, and residues from coking or cracking processes.

[0003] Such gate valves are often designed as knife gate valves, with single- or double-plate gate valves being the primary options. Double-plate gate valves, whose basic principle is based on a technology developed by the applicant, have proven particularly effective for use in ethylene plants. In such knife gate valves, the gate plates are pushed apart in the shut-off position by an interposed expansion element, specifically a wedge-in-wedge arrangement, upon actuation of a gate rod connected to the expansion element, and pressed against the corresponding body sealing seats to improve the sealing effect. Such a knife gate valve is known from EP 0 450 646 A2, owned by the applicant.

[0004] A particular problem with such knife gate valves has been identified as the erosion of the body seal seats caused by particles in the flowing fluid. This creates a point-like penetration during the initial opening phase of the knife gate valve, which, due to the pressurized fluid, creates a fluid flow at very high speed. The particles in this fluid flow cause severe erosion on the body seal seats, particularly on the body seal seat of the valve's outlet nozzle. This deteriorates the sealing effect over the service life of the knife gate valve, increasing maintenance requirements and shortening the service life of the valve.

[0005] To counteract the erosion of the casing sealing seats, a knife gate valve was developed, for example, which uses a baffle plate to redirect the fluid flow containing the particles in such a way that direct flow to the outlet-side casing sealing seat is prevented, particularly during the initial phase of the opening process, when a very high flow velocity prevails due to the point-shaped opening cross-section. Such a knife gate valve is known, for example, from the aforementioned DE 10 2016 111 169 A1.

[0006] However, the knife gate valve described in DE 10 2016 111 169 A1 has the disadvantage that the baffle plate is exposed to high abrasive loads due to the particle-containing fluid flow. Furthermore, the baffle plate causes increased turbulence in the fluid flow within the knife gate valve due to the deflection, thus increasing pressure loss through the knife gate valve and subjecting other components of the knife gate valve to abrasive loads due to the flow deflection.

[0007] A significant improvement is achieved by the aforementioned knife gate valve from DE 10 2022 105 939 A1 by the applicant. It has been shown that in special situations, for example, when the angle of repose is steep, the abrasion load can be further reduced.

[0008] The invention is based on the object of further improving the knife gate valve mentioned at the outset in such a way that an increased service life and increased erosion resistance are achieved even in special operating situations.

[0009] According to the invention, this object is achieved with regard to the knife gate valve by the subject matter of claim 1.

[0010] Specifically, the task is performed by a knife gate valve for chemical and / or petrochemical industrial plants, comprising: - a gate valve body having an inlet port with an outlet opening and an outlet port with an inlet opening, which correspond to each other in an open position of the gate valve; - a shut-off device with at least one shut-off plate and a pipe bridge, which is movably arranged between the inlet and outlet nozzles for opening and closing the knife gate valve; and - at least one guide device for flow guidance. According to the invention, the guide device has at least one guide element arranged on an inner wall of the inlet nozzle and reducing the size of the outlet opening of the inlet nozzle such that, when the knife gate valve is opened, an opening cross-section of the outlet opening is enlarged at the moment of an initial, in particular first, flow entry into the pipe bridge. The guide device has at least one plate guide element arranged on an inner wall of the pipe bridge and extending in the flow direction.

[0011] The fluid flow includes process media such as steam and / or hydrocarbons. The inlet port may also be referred to as the inlet flange, and the outlet port may be referred to as the outlet flange.

[0012] The invention has the advantage that when the knife gate valve is opened at the moment of the first flow entry, i.e. at the moment a passage opening is formed, from the inlet nozzle into the pipe bridge, the flow velocity of an incoming, particle-laden fluid stream is reduced by the enlarged opening cross-section. In contrast to the knife gate valve according to DE 10 2016 111 169 A1, according to the invention, an enlarged opening cross-section is provided at the outlet opening of the inlet nozzle into the pipe bridge at the moment of opening. As a result, the fluid flows into the pipe bridge at the moment of opening, distributed over a comparatively larger opening cross-section. This has the advantage that a nozzle effect, as occurs in the knife gate valve according to DE 10 2016 111 169 A1, is reduced or even prevented.This protects, for example, a body seal seat located opposite the opening cross-section of the outlet opening of the inlet nozzle in the direction of flow, or an outlet-side body seal seat, from the point-like impact of the particle-laden fluid flow. Erosion of the body seal seat is thus prevented or at least significantly reduced, resulting in increased functional reliability and a longer service life for the knife gate valve.

[0013] The guide element reduces the outlet opening of the inlet nozzle such that the opening cross-section of the outlet opening is enlarged at the moment the flow first enters the pipe bridge. In other words, the guide element protrudes into the outlet opening to reduce the outlet opening. Or in other words, the guide element limits the outlet opening so that it is reduced. The guide element can reduce the outlet opening of the inlet nozzle by up to 10 percent, in particular by up to 7 percent. Preferably, the guide element reduces the outlet opening of the inlet nozzle by up to 5 percent. To increase the opening cross-section, the guide element has a specific shape that preferably approximates an inner contour of the pipe bridge.This means that the guide element, on the one hand, narrows the outlet opening due to its extension transverse to a longitudinal direction of the inlet nozzle and, on the other hand, increases the opening cross-section of the outlet opening into the pipe bridge in the opening phase due to its shape.

[0014] The guide element is preferably designed such that, at the moment of the first flow entry from the inlet nozzle into the pipe bridge, the opening cross-section of the outlet opening of the inlet nozzle forms a cross-sectional shape that deviates from a point-shaped cross-section. This corresponds, for example, to the enlarged opening cross-section. At the moment of the first flow entry from the inlet nozzle into the pipe bridge, the opening cross-section preferably has at least one passage area. The opening cross-section here has a greater extent than a point-shaped opening. Particularly preferably, the opening cross-section forms at least one gap at the moment of the first flow entry from the inlet nozzle into the pipe bridge. The gap is preferably arc-shaped in sections. In other words, the gap is preferably circular segment-shaped in sections. Alternatively or additionally, the gap can be linear at least in sections.Alternatively or additionally, the opening cross-section at the moment of initial flow entry from the inlet nozzle into the pipe bridge can be linear. Other opening cross-section geometries are possible.

[0015] The guide element preferably has, at the position of the outlet opening of the inlet nozzle, a shape adapted to an inner contour, in particular an inner circumference, of the pipe bridge in order to enlarge the opening cross-section.

[0016] The opening cross-section is limited at the moment and during the entire opening process by a contour of the inner wall of the inlet nozzle, the guide element, and the pipe bridge, in particular an inner contour of the pipe bridge. In other words, a contour of the inner wall of the inlet nozzle, the guide element, and the pipe bridge define the size of the opening cross-section of the outlet opening of the inlet nozzle during opening and closing of the knife gate valve.

[0017] The shape of the guide element, preferably approximating the inner contour of the pipe bridge, is one way to increase the opening cross-section of the outlet opening of the inlet nozzle. Another way to increase the opening cross-section is to design an outer contour of the guide element with a straight outer edge. The outer edge preferably extends transversely to the opening and closing direction of the knife gate valve. In general, the shape of the guide element, specifically the outer edge of the guide element, deviates from the shape of the inner wall of the inlet nozzle.

[0018] The shape of the guide element, specifically the outer edge of the guide element, deviates from the shape of the inner wall of the inlet nozzle in such a way that a nozzle-shaped opening cross-section of the outlet opening of the inlet nozzle of the knife gate valve is avoided or at least eliminated more quickly than in the prior art. This opening cross-section occurs in the prior art when the pipe bridge and the inlet nozzle overlap due to the opposing curvatures of the inner walls. A nozzle-shaped, point-shaped opening cross-section is avoided if, for example, the guide element, specifically the outer edge of the guide element, and the pipe bridge have the same radii of curvature, which lead to a linear opening cross-section. A nozzle-shaped, point-shaped opening cross-section is eliminated more quickly than in the prior art if, for example, the guide element, specifically the outer edge of the guide element, is straight, since the opening cross-section then increases more quickly than in the prior art.

[0019] In general, there is a time delay between the initial flow entry and the state of the art. This time delay allows the opening cross-section to be enlarged during the initial opening phase until effective flow begins without the harmful jet effect occurring. The jet effect is at least reduced.

[0020] The time delay in the opening of the inlet nozzle has the further effect that the outlet nozzle is open further relative to the inlet nozzle at the same time. The opening cross-section of the outlet nozzle is therefore larger than the opening cross-section of the inlet nozzle at the same time.

[0021] The invention therefore has two effects. At the inlet nozzle, the guide element prevents the formation of a nozzle-like, "point-like" opening or enlarges the opening more quickly than in the prior art. At the outlet nozzle, the invention results in the opening cross-section of the outlet nozzle being larger than the opening cross-section of the inlet nozzle at the same time, because the guide element delays the opening of the inlet nozzle. The outlet nozzle is wider open relative to the inlet nozzle at the same time.

[0022] In both cases, i.e. with a straight or curved outer edge, or generally in connection with the invention, the guide element, specifically the outer edge of the guide element, is arranged so close to the plane spanned by the outlet opening of the inlet nozzle that the guide element at least temporarily shields the outlet opening against the passage of the fluid flow when the knife gate valve opens. This prevents a fluid flow from immediately passing through the outlet opening upon opening and thus destroying the effect according to the invention. For the shielding effect, the guide element does not necessarily have to be directly adjacent to the plane or touch the blocking device. A small distance between the guide element, specifically its outer edge, and the plane is possible, provided there is no significant fluid flow, e.g.due to turbulence, it passes the guide element through the knife gate valve before the inner wall of the pipe bridge has passed the guide element, specifically its outer edge, when it opens.

[0023] In other words, the guide element seals against the blocking device in such a way that the fluid flow through the knife gate valve is delayed upon opening. The guide element serves a temporary blocking function when the knife gate valve opens.

[0024] The guide element forms a stationary or fixed blocking element that acts temporarily upon opening. The guide element is fixed to the inlet nozzle. In contrast, the blocking device is movable.

[0025] The locking device is movably arranged between the inlet and outlet ports. Preferably, the locking device is arranged so as to be linearly movable between the inlet and outlet ports. Specifically, the locking device is preferably displaceable between the open position and a closed position of the knife gate valve.

[0026] In the open position, the inlet and outlet ports are connected by the pipe bridge. In the closed position, the inlet and outlet ports are separated from each other by at least one shut-off plate.

[0027] During an opening or closing process of the knife gate valve, the locking device is moved, preferably by a slide rod. The travel distance between the open position and the closed position corresponds to a total stroke of the locking device, in particular the slide rod. In the closed position, the locking device is arranged at a minimum stroke position, and in the open position, the locking device is arranged at a maximum stroke position. In other words, the locking device has a stroke of 0 percent of the total stroke in the closed position and a stroke of 100 percent of the total stroke in the open position.

[0028] The stroke range in which the opening cross-section of the outlet opening of the inlet nozzle influences an applied process pressure can range from 0 percent to 35 percent of the total stroke. This stroke range corresponds to the opening phase of the knife gate valve. The opening phase, in which the moment of first flow entry through the outlet opening of the inlet nozzle into the pipe bridge occurs, can occur at a stroke of the blocking device of 22 percent to 35 percent, in particular from 22 percent to 30 percent, of the total stroke. Preferably, the moment of first flow entry through the outlet opening of the inlet nozzle into the pipe bridge occurs at a stroke of the blocking device of 23 percent to 28 percent, in particular from 24 percent to 26 percent of the total stroke. Particularly preferably, the moment of first flow entry through the outlet opening of the inlet nozzle into the pipe bridge occurs at a stroke of 25 percent of the total stroke.

[0029] The outlet opening of the inlet nozzle and the inlet opening of the outlet nozzle preferably adjoin the blocking device. Housing sealing seats are preferably located at the position of the outlet opening and the inlet opening to cooperate with the blocking device for sealing.

[0030] The knife gate valve is particularly preferably designed as a double-knife gate valve. In this case, the shut-off device preferably comprises two shut-off plates arranged concentrically in a plate cage. The shut-off plates or the pipe bridge preferably rest against the housing sealing seats in the closed or open position.

[0031] According to the invention, the guide device comprises at least one plate guide element arranged on an inner wall of the pipe bridge and extending in the direction of flow. Thus, in addition to the guide element on the inner wall of the inlet nozzle, the guide device also has the plate guide element on the inner wall of the pipe bridge. The plate guide element is arranged downstream of the guide element in the open position in the direction of flow. This results from the arrangement of the guide element in the inlet nozzle and the plate guide element in the pipe bridge.

[0032] The invention has the advantage that the plate guide element shields the edges of the knife gate valve located in the flow path during the initial opening phase, i.e., when the flow cross-section of the pipe bridge is moved into the flow cross-section of the inlet nozzle and partially overlaps it. To this end, the plate guide element extends in the direction of flow and provides additional abrasion protection in addition to the guide element in the inlet nozzle.

[0033] Particles that can enter the flow shadow of the guide element in the initial opening phase at steep angles of repose are effectively deflected by the plate guide element from the edges in the flow path and are essentially redirected parallel to the longitudinal axis of the pipe bridge.

[0034] This ensures erosion protection even in special applications.

[0035] Preferred embodiments of the invention are specified in the subclaims.

[0036] In a preferred embodiment, the guide element is designed such that, when the knife gate valve is opened, the outlet opening of the inlet nozzle can be released or is released with a delay relative to the inlet opening of the outlet nozzle. During an opening process, the pipe bridge first overlaps with the inlet opening of the outlet nozzle and then, at a later time, with the outlet opening of the inlet nozzle. Thus, the guide element first releases an opening cross-section of the inlet opening of the outlet nozzle into the pipe bridge, followed by the opening cross-section of the outlet opening of the inlet nozzle.

[0037] The outlet opening of the inlet nozzle and the inlet opening of the outlet nozzle are preferably arranged concentrically. Due to the delayed release of the outlet opening of the inlet nozzle, the inlet opening of the outlet nozzle has a larger opening cross-section than the outlet opening at the moment of initial flow entry into the pipe bridge. This has the advantage that a fluid flow from the casing sealing seat at the outlet nozzle enters the pipe bridge offset, thus preventing direct flow onto the casing sealing seat. This at least reduces erosion of the casing sealing seat and increases the service life of the knife gate valve.

[0038] In a preferred embodiment, the guide element is adapted such that the opening cross-section forms at least one gap between the pipe bridge and the inlet nozzle at the moment of the first flow entry from the inlet nozzle into the pipe bridge. The gap preferably extends in a plane with the shut-off plate. The gap results in an enlarged opening cross-section compared to the known point-shaped opening cross-section.

[0039] Preferably, the guide element is adapted such that the gap is arcuate in sections and linear in sections. The shape of the gap can therefore combine different geometries. This is the case, for example, with a straight outer edge of the guide element. A first longitudinal side of the gap is straight or linear and the opposite second longitudinal side of the gap is arcuate. The straight longitudinal side is determined by the outer edge of the guide element and the arcuate, curved longitudinal side is determined by the inner wall of the pipe bridge. It has surprisingly been shown that this type of gap shape is particularly favorable in terms of flow.

[0040] It is not necessary for the outer edge of the guide element to be in the plane of the outlet opening of the inlet nozzle. The distance between the outer edge and the plane of the outlet opening is such that unwanted passage of fluid during the initial opening phase is avoided or at least significantly reduced, creating a shielding effect.

[0041] The guide element has at least one outer contour at the outlet opening of the inlet nozzle, which extends transversely to the opening and closing direction of the knife gate valve. The transverse extension of the outer contour shields part of the outlet opening of the inlet nozzle from the fluid flow. The outer contour can have the aforementioned straight outer edge, in particular a horizontally arranged straight outer edge. Alternatively, the outer contour can have a curved outer edge.

[0042] In a further preferred embodiment, the guide element has at least one outer contour at the outlet opening of the inlet nozzle, which corresponds to an inner contour of a passage of the pipe bridge. In other words, the guide element has at least one outer contour at the position of the outlet opening of the inlet nozzle, the shape of which corresponds to an inner contour of a passage of the pipe bridge. The outer contour of the guide element and the inner contour of the passage preferably adjoin one another in a longitudinal direction of the inlet nozzle. The pipe bridge, with the inner contour of the passage, is relatively movable transversely to the longitudinal direction of the inlet nozzle with respect to the outer contour of the guide element. The outer contour of the guide element is preferably an outer edge arranged at the position, in particular in the longitudinal direction, of the outlet opening of the inlet nozzle.The inner contour of the passage of the pipe bridge is preferably part of an inner circumference of the passage. The passage is preferably an opening through the pipe bridge, which, at least in the open position, fluidically connects the inlet and outlet nozzles. During the opening process, at the moment the flow first enters the passage of the pipe bridge, an elongated opening cross-section is released, through which the fluid flow flows into the passage in a distributed manner. This reduces the flow velocity of the fluid flow and thus the erosion effect, for example, on the outlet-side housing sealing seat. These statements also apply to the embodiment with a straight outer edge.

[0043] The outer contour of the guide element and the inner contour of the passage of the pipe bridge preferably have the same, in particular the same, radius of curvature. The outer contour of the guide element can be circular in shape. The inner contour of the passage of the pipe bridge can be circular. The outer contour of the guide element is preferably convex. It is possible for the outer contour of the guide element to have the same radius of curvature as the inner contour of the passage in some sections. The passage of the pipe bridge is preferably cylindrical. The passage is preferably part of a compensator unit of the pipe bridge. The design of the outer and inner contours as a curve has the advantage that the opening cross-section of the outlet opening of the inlet nozzle is linear or gap-shaped at the moment of the first flow entry into the passage of the pipe bridge, thus achieving a comparatively calm inflow of the fluid flow.This also applies to the version with a straight outer edge.

[0044] Further preferably, the outer contour extends transversely to the longitudinal direction of the inlet nozzle, starting from the inner wall inwards. In other words, the outer contour of the guide element runs from the inner wall of the inlet nozzle transversely to the longitudinal direction into the interior of the inlet nozzle, thus reducing the size of the outlet opening. The outer contour of the guide element is arranged in the longitudinal direction of the inlet nozzle at the position of the outlet opening. The outer contour of the guide element preferably has two ends that are in contact with the inner wall. Furthermore, the outer contour of the guide element preferably has at least one vertex that lies transversely to the longitudinal direction in the interior of the inlet nozzle. In other words, the vertex is offset inwards from the inner wall of the inlet nozzle transversely to the longitudinal direction, or spaced therefrom.This embodiment represents a simple solution to reduce the outlet opening on the one hand and to increase the opening cross-section at the moment of the first flow entry on the other hand.

[0045] In a preferred embodiment, the guide element has a surface that is straight and projects into the inlet nozzle along the flow direction with increasing distance from the inner wall. The guide element is preferably a flat element that extends over a region of the inner wall of the inlet nozzle. The increasing distance results in a continuous reduction in the effective flow cross-section of the inlet nozzle in order to, on the one hand, enlarge the opening cross-section of the outlet opening of the inlet nozzle and, on the other hand, to redirect the fluid flow with the least possible turbulence, so that the outlet opening of the inlet nozzle is temporarily shielded during the initial opening phase. Impact of the fluid flow in the manner of a baffle plate and the resulting strong turbulence of the fluid are largely avoided.

[0046] Alternatively, the surface can curve from the inner wall into the interior of the inlet nozzle. The guide element preferably has a hump-like shape. The guide element is preferably a flat element that extends over a region of the inner wall of the inlet nozzle. The surface of the guide element preferably has a convex curvature that extends into the interior of the inlet nozzle. The curvature of the surface preferably runs transversely and / or in the longitudinal direction of the inlet nozzle.

[0047] The surface of the guide element preferably faces the interior of the inlet nozzle. The guide element is preferably flush with the surface on the inner wall of the inlet nozzle. The guide element can be made of sheet metal. A cavity can be provided between the guide element and the inner wall of the inlet nozzle. Alternatively, the guide element can be made of a solid material that fills a space between the surface of the guide element in the inner wall of the inlet nozzle. The curved surface advantageously has a flow-optimized shape so that pressure loss in the knife gate valve is kept to a minimum. In contrast, in the knife gate valve according to DE 10 2016 111 169 A1, an increased back pressure builds up due to the impacting fluid flow, particularly when the knife gate valve is in the open position.In the described embodiment of the knife gate valve according to the invention, there is no increased pressure on the guide element when the knife gate valve is open. Furthermore, the curved shape has the advantage that there is no impact of the fluid flow, as with the baffle plate known from the prior art, thus reducing wear on the guide element. The same explanations apply to a guide element with a straight surface that rises in the direction of flow, i.e., that protrudes continuously and increasingly into the interior of the inlet nozzle in the direction of flow.

[0048] The guide element is preferably designed to rise in the flow direction towards the outlet opening of the inlet nozzle. In other words, the guide element forms a rising ramp in the flow direction from the inner wall to the outlet opening of the inlet nozzle. The guide element can run continuously, in particular uniformly, rising towards the outlet opening. More preferably, the guide element extends at least partially in a longitudinal direction of the inlet nozzle and ends at the outlet opening of the inlet nozzle. In other words, the guide element has an end which is arranged in the longitudinal direction of the inlet nozzle at the position of the outlet opening. The outer contour of the guide element is preferably formed at the end. The guide element can extend in sections or over the entire length of the inlet nozzle. This embodiment has fluidic advantages. Here, the fluid flow is continuous, i.e.The air is guided toward the outlet opening without any impact edge or step. These specifications apply to both the guide element with a straight surface and the guide element with a curved surface.

[0049] The guide element can have a triangular cross-section or, together with the inner wall, form a triangular cross-section. This embodiment is to be viewed in connection with the guide element with a straight surface that protrudes continuously into the interior of the inlet nozzle in the direction of flow. The guide element can have a triangular cross-section, such as in the case of a solid guide element. If the guide element is designed as a sheet metal, the sheet metal and the inner wall together form the triangular cross-section.

[0050] The triangular cross-section can extend along the width, in particular the entire width, of the guide element. It is understood that the size of the triangular cross-section varies in the circumferential direction of the inlet nozzle. If the triangular cross-section extends along the width, in particular the entire width, of the guide element, the guide element gradually deflects the fluid flow to shield the outlet opening.

[0051] Preferably, a drainage gap is formed between the guide element and the inner wall of the inlet nozzle. This allows liquid, such as condensate, to drain away in a controlled manner.

[0052] In a preferred embodiment, the inlet nozzle and the outlet nozzle each have a sealing seat for the at least one shut-off plate. Preferably, the inlet nozzle and the outlet nozzle each have a sealing seat for a total of two shut-off plates in order to provide a tight connection in the closed position. The guide element, in particular the outer contour, is offset at least partially inwards from the sealing seat of the outlet nozzle transversely to the longitudinal direction. This has the advantage that when the knife gate valve is opened, the opening cross section of the outlet opening of the inlet nozzle is released with a delay in relation to an opening cross section of the inlet opening of the outlet nozzle. This prevents direct flow onto the sealing seat of the outlet nozzle and thus at least reduces or completely prevents erosion of the sealing seat.

[0053] In one embodiment, the opening cross-section of the inlet opening of the outlet nozzle is larger than the opening cross-section of the outlet opening of the inlet nozzle when the knife gate valve is opened and / or in the open position of the knife gate valve. The opening cross-section of the outlet opening of the inlet nozzle and the opening cross-section of the inlet opening of the outlet nozzle can have a ratio of at least 1 to 2 ("1:2"). A ratio of the opening cross-sections greater than 1 to 2 is possible. The ratio refers to the areas of the opening cross-sections.

[0054] The guide device can have an additional guide element arranged between the shut-off plate and the pipe bridge in a displacement direction of the shut-off device. The additional guide element forms a flow channel transverse to the displacement direction, which connects the inlet nozzle with the outlet nozzle, at least when the knife gate valve is opened. For the advantages, reference is made to those explained in connection with the knife gate valve described below.

[0055] According to the independent claim 17, the invention relates to a knife gate valve, in particular a double knife gate valve, for chemical and / or petrochemical industrial plants, comprising: - a gate valve body having an inlet port with an outlet opening and an outlet port with an inlet opening, which correspond to each other in an open position of the gate valve; - a shut-off device with at least one shut-off plate, in particular two shut-off plates, and a pipe bridge, which are movably arranged between the inlet and outlet nozzles for opening and closing the knife gate valve; and - at least one guide device for flow guidance.The guide device has at least one guide element which is arranged in a displacement direction of the blocking device between the shut-off plate and the pipe bridge, wherein the guide element forms a flow channel transverse to the displacement direction which connects the inlet nozzle to the outlet nozzle at least when the knife gate valve is opened.

[0056] This has the advantage that when the knife gate valve opens, the flow channel is opened before a passage from the outlet opening of the inlet nozzle into the passage of the pipe bridge is opened. This means that the inlet-side fluid pressure is already reduced, or the contamination deposited on the inlet side is at least partially removed by the flow channel. As a result, the fluid flow through the passage of the pipe bridge contains fewer particles, thus protecting the outlet-side body seal seat. This increases the erosion resistance and service life of the knife gate valve.

[0057] The knife gate valve preferably has at least two guide elements, each forming a flow channel transverse to the direction of displacement through the blocking device. In a preferred embodiment, the guide element is integrated into the blocking device, with the flow channel extending completely through the blocking device transverse to the direction of displacement. The guide element is preferably formed by at least one pipe section.

[0058] According to the independent claim 20, the invention relates to a method for operating a knife gate valve, in particular one of the knife gate valves of the aforementioned type, for chemical and / or petrochemical industrial plants, in which the knife gate valve comprises a valve housing with an inlet nozzle and an outlet nozzle and a blocking device which is displaced in the valve housing between an open position and a closed position for opening and closing the knife gate valve. The blocking device has at least one shut-off plate and a pipe bridge with a passage which, in the open position, is arranged such that the inlet nozzle with an outlet opening and the outlet nozzle with an inlet opening are connected to one another through the passage of the pipe bridge. In the closed position, the blocking device is arranged such that the inlet nozzle and the outlet nozzle are blocked off from one another by the shut-off plate.The knife gate valve has at least one guide device with at least one guide element for flow guidance, which is arranged on an inner wall of the inlet nozzle and reduces the size of the outlet opening of the inlet nozzle. When the blocking device is moved from the closed position to the open position, an enlarged, in particular gap-shaped, opening cross-section of the outlet opening of the inlet nozzle is released at the moment of an initial, in particular first, flow entry into the passage of the pipe bridge, which opening cross-section is defined by the guide element and the passage of the pipe bridge. In a preferred embodiment of the method according to the invention, the opening cross section of the outlet opening of the inlet nozzle is released linearly, in particular uniformly, over the entire displacement path of the blocking device when the knife gate valve is opened.

[0059] According to the independent claim 22, the invention relates to a method for operating a knife gate valve, in particular one of the knife gate valves of the aforementioned type, for chemical and / or petrochemical industrial plants, in which the knife gate valve comprises a valve housing with an inlet nozzle and an outlet nozzle and a blocking device which is displaced in the valve housing between an open position and a closed position for opening and closing the knife gate valve. The blocking device has at least one shut-off plate and a pipe bridge with a passage which, in the open position, is arranged such that the inlet nozzle with an outlet opening and the outlet nozzle with an inlet opening are connected to one another through the passage of the pipe bridge. The blocking device is arranged in the closed position such that the inlet nozzle and the outlet nozzle are blocked off from one another by the shut-off plate.The knife gate valve has at least one guide device with at least one guide element for flow guidance, which is arranged between the shut-off plate and the pipe bridge in a displacement direction of the blocking device. The guide element forms a flow channel transverse to the displacement direction, which, when the blocking device is moved from the closed position to the open position, connects the inlet nozzle with the outlet nozzle before the passage of the pipe bridge exposes an opening cross-section of the outlet opening of the inlet nozzle.

[0060] The plate guide element is preferably arranged in a front region in the opening direction, in particular in the front half of the pipe bridge in the opening direction. This ensures that the plate element reaches the critical area in the initial phase of the opening movement of the pipe bridge and provides effective erosion protection. The distance between the guide element and the plate guide element in the opening direction, when the pipe bridge is in the closed position, determines the point in time at which the plate guide element sweeps over the flow cross-section of the inlet nozzle and becomes effective. The smaller the distance, the shorter the dead time until the plate guide element reaches the flow cross-section of the inlet nozzle.The determination of the distance in the opening direction when the knife gate valve is completely closed is determined by the specialist depending on the point in time during the initial phase of opening when the abrasive load is particularly high and the plate guide element is to become effective.

[0061] Furthermore, the plate guide element preferably extends over the entire height of the pipe bridge. This effectively shields the edge opposite the outlet nozzle in the direction of flow.

[0062] The plate guide element can be curved to match the curvature of the inlet nozzle. When this passes the inner wall of the inlet nozzle during the initial opening phase, optimal shielding is achieved because the curvature of the plate guide element corresponds to the curvature of the inlet nozzle and thus also to the curvature of the outlet nozzle. The plate guide element then temporarily limits the partial flow cross-section of the pipe bridge that arises in the initial phase, thus shielding the entire free edge at the outlet nozzle.

[0063] A modified version provides for a straight plate guide element. This has the advantage of being easy to manufacture and provides better shielding.

[0064] When using one of the knife gate valves of the aforementioned type, these are used in a cracking process and / or a coking process.

[0065] The invention will be explained in more detail below with reference to the accompanying drawings. The illustrated embodiments represent examples of how the knife gate valve according to the invention can be designed.

[0066] The exemplary embodiments without a plate guide element serve to explain the function of the guide element in the inlet nozzle. These exemplary embodiments are conceptually supplemented by the plate guide element according to the invention in the pipe bridge. In other words, all exemplary embodiments comprise the at least one guide element in the inlet nozzle and the at least one plate guide element in the pipe bridge, even if the plate guide element in the pipe bridge is not explicitly shown or described. Some figures explicitly show the combination of guide element and plate guide element.

[0067] The drawings show Fig. 1 a longitudinal section through a knife gate valve according to a preferred embodiment of the invention, wherein a locking device of the knife gate valve is in a closed position; Fig. 2 a perspective detailed view of an inlet nozzle with a guide device of the knife gate valve according to Fig. 1; Fig. 3 a longitudinal section through the knife gate valve according to Fig. 1, wherein the locking device of the knife gate valve is in a position where only the inlet opening of the outlet nozzle of the knife gate valve is connected to the passage of the pipe bridge; Fig. 4 a perspective detailed view of the inlet nozzle and the guide device of the knife gate valve according to Fig. 1, wherein an opening cross-section of the outlet opening of the inlet nozzle in the position according to Fig. 3 is shown; Fig. 5 a schematic representation to illustrate the opening cross-section of the outlet opening of the inlet nozzle in the position according to Fig. 3, which shows the moment of first flow entry into the pipe bridge; Fig. 6 a longitudinal section through the knife gate valve according to Fig. 1, wherein the locking device of the knife gate valve is moved further towards the open position; Fig. 7 a perspective detailed view of the inlet nozzle and the guide device of the knife gate valve according to Fig. 1, wherein the opening cross-section of the outlet opening of the inlet nozzle is further enlarged; Fig. 8 a diagram showing the opening phase of the outlet opening of the inlet nozzle of the knife gate valve according to Fig. 1; Fig. 9 is a plan view of a knife gate valve according to a further embodiment of the invention; and Fig. 10 a perspective, partially transparent view of a locking device of the knife gate valve according to Fig. 9. Fig. 11 is a plan view of a knife gate valve in the region of the inlet nozzle according to a further embodiment of the invention, in which the guide element has a straight outer edge; Fig. 12 a perspective view of the knife gate valve according to Fig. 11 in the area of ​​the inlet nozzle; Fig. 13 a section of the inlet nozzle of the knife gate valve according to Fig. 11; Fig. 14 a perspective view of the cut inlet nozzle according to Fig. 13 and the corresponding cut outlet nozzle; Fig. 15 a schematic representation to illustrate the opening cross-section of the outlet opening of the inlet nozzle according to Fig. 11 in a position showing the moment of first flow entry into the pipe bridge; Fig. 16 is a perspective view of a sectioned pipe bridge with a curved plate guide element according to an embodiment of the invention; Fig. 17 a perspective view of the barrier device with the pipe bridge according to Fig. 16; Fig. 18 a plan view of the pipe bridge according to Fig. 16; Fig. 19 a perspective view of a sectioned knife gate valve according to an embodiment of the invention with a guide element in the inlet nozzle and a plate guide element in the pipe bridge according to the Fig. 16 to 18 in the initial phase of opening (partial flow cross-section); Fig. 20 a perspective view of the knife gate valve according to Fig. 19 in the fully open state (full flow cross-section); Fig. 21 a perspective view of the knife gate valve according to Fig. 19 when fully closed; Fig. 22 a perspective view of a sectioned barrier device, the pipe bridge of which has a straight plate guide element according to a further embodiment of the invention and Fig. 23 a perspective view of a sectioned knife gate valve according to an embodiment of the invention with a guide element in the inlet nozzle and the plate guide element in the pipe bridge according to Fig. 22 in the initial phase of opening (partial flow cross-section)

[0068] In the following description, the same reference numbers are used for identical and equivalent parts.

[0069] The Fig. 1 to 7 show a knife gate valve 10 according to a preferred embodiment of the invention, wherein the knife gate valve 10 is a double-knife gate valve.

[0070] The knife gate valve 10 has a valve housing 11 that fluid-tightly surrounds the internals located within the valve housing 11. The valve housing 11 has an inlet nozzle 12 and an outlet nozzle 14. The inlet and outlet nozzles 12, 14 are each designed as pipe nozzles. When assembled, the inlet and outlet nozzles 12, 14 are flanged to corresponding lines (not shown), for example, a transfer line or a decoking line.

[0071] The inlet nozzle 12 has an outlet opening 13, and the outlet nozzle 14 has an inlet opening 15, which correspond to each other in an open position of the knife gate valve 10. The inlet and outlet nozzles 12, 14 are located on a common longitudinal axis.

[0072] Furthermore, the knife gate valve 10 has a blocking device 16, which comprises two shut-off plates 17 and a pipe bridge 18. The pipe bridge 18 has at least one plate guide element 46 (not shown). For the position and shape of the plate guide element 46, reference is made to Fig. 16 to 21. The two variants of the plate guide element 46 can be combined as desired with the knife gate valve 10. The combinations are expressly described in connection with the Fig. 1 to 15, provided that they are new.

[0073] The shut-off plates 17 are inserted into a plate cage 34. The shut-off plates 17 are arranged concentrically and parallel to one another and, in a closed position, block off the inlet and outlet nozzles 12, 14. The shut-off plates 17 are loosely inserted into the plate cage 34 so that they can be moved in the axial direction, i.e., perpendicular to the surface of the shut-off plates 17. In other words, the blocking device 16 can be moved transversely to the longitudinal axis of the nozzles 12, 14. This is used to press the shut-off plates 17, in the closed position, against the housing sealing seats 29 provided on the slide valve housing 11. For this purpose, an expansion element 35 is arranged between the two shut-off plates 17 and is connected to a slide rod 36. The slide rod 36 is mounted in a fluid-tight manner in the slide valve housing 11 and can be moved in the longitudinal direction by a drive (not shown).The expansion member 35 has an inner wedge 37, which is arranged in an outer wedge 38 on the inside of the shut-off plates 17. To center the expansion member 35, a centering ball 39 is arranged between the jaws of the inner wedge 37.

[0074] The pipe bridge 18 is firmly connected to the plate basket 34. In other words, the pipe bridge 18 is arranged on the plate basket 34 on a side opposite the slide rod 36. The pipe bridge 18 has a passage 26 which, in the open position, is aligned with the inlet and outlet nozzles 12, 14. The pipe bridge 18 is connected to the plate basket 34 in such a way that it can be moved, together with the plate basket 34, into the open or closed position by actuating the slide rod 36. For this purpose, the plate basket 34 and the pipe bridge 18 are moved between two parallel guide plates.

[0075] The pipe bridge 18 has a compensator unit 41 that encloses the passage 26. The compensator unit 41 has two sealing rings 42 that are arranged concentrically and axially spaced from each other. A compensator shaft 43 is arranged between the two sealing rings 42. In the present embodiment, this shaft is designed with multiple shafts. Single-shaft compensator shafts are also possible, especially for smaller nominal diameters.

[0076] When the gate valve rod 36 is actuated, the inner wedge 37 is moved into the outer wedge 38, causing the two shut-off plates 17 to spread apart. The spreading movement presses the two shut-off plates 17 against the housing sealing seats 29, thereby achieving a good sealing effect in the closed position of the knife gate valve 10.

[0077] The Fig. 1, Fig. 3 and Fig. 6 shows an opening process of the knife gate valve 10, in which the locking device 16 is moved from the closed position to the open position. For this purpose, the locking device 16 is movably arranged between the inlet and outlet ports 12, 14.

[0078] The knife gate valve 10 further comprises a guide device 19 for directing an incoming fluid flow. The guide device 19 has a guide element 21 arranged on an inner wall 22 of the inlet nozzle 12. The guide element 21 is arranged on the inner wall 22 of the inlet nozzle 12 on the pipe bridge side, as viewed in the direction of displacement of the blocking device 16.

[0079] The inner wall 22 of the inlet nozzle 12 is cylindrical. The inner wall 22 of the inlet nozzle 12 has an inner circumference against which the guide element 21 rests.

[0080] As in the Fig. 1, Fig. 3 and Fig. 6, the guide element 21 extends in a longitudinal direction of the inlet nozzle 12 and ends at the position of the outlet opening 13 of the inlet nozzle 12. The guide element 21 extends approximately over the entire length of the inlet nozzle 12. The guide element 21 rises towards the outlet opening 13 of the inlet nozzle 12. In other words, the guide element 21 is designed to extend obliquely into the interior of the inlet nozzle 12 towards the outlet opening 13. The guide element 21 is designed to be ramp-shaped towards the outlet opening 13 of the inlet nozzle 12. The guide element 21 has a surface 28 which faces the interior of the inlet nozzle 12. This surface is in contact with the fluid or a fluid flow during operation. The surface 28 is flush with the inner wall 22 of the inlet nozzle 12. This is shown in the Fig. 2 and Fig. 4. The surface 28 covers an area of ​​the inner wall 22.

[0081] Furthermore, the Fig. 2, Fig. 4, Fig. 5 and Fig. 7 shows that the surface 28 of the guide element 21 is curved. The guide element 21 is hump-shaped due to the curved surface 28. In other words, the guide element 21 is a flat element that extends over a region of the inner wall 22 of the inlet nozzle 12. Specifically, the surface 28 of the guide element 21 has a convex curvature transverse to the longitudinal direction of the inlet nozzle 12, which extends into the interior of the inlet nozzle 12. The guide element 21 is bowl-shaped in sections.

[0082] The guide element 21 is formed from sheet metal. In other words, the guide element 21 forms a guide plate. It is possible for the guide element 21 to be designed as a guide plate. In contrast to a guide plate, a guide plate has a greater wall thickness. Alternatively, the guide element 21 can be formed from a solid material that completely fills a space between the surface 28 and the inner wall 22 of the inlet nozzle 12.

[0083] The guide element 21 ends in the longitudinal direction at the position of the outlet opening 13 of the inlet nozzle 12. At this position, the guide element 21 has an outer contour 24 that corresponds to an inner contour 25 of the passage 26 of the pipe bridge 18. In the longitudinal direction of the inlet nozzle 12, the inner contour 25 and the outer contour 24 are arranged adjacent. At the position of the outlet opening 13, the inlet nozzle 12 has one of the two sealing seats 29. Along the common longitudinal axis of the outlet opening 13, the outlet nozzle 14 has another of the two sealing seats 29 at the position of the inlet opening 15. Due to the shape of the outer contour 24, the guide element 21 is offset inward from the sealing seat 29 of the outlet nozzle 14 and in particular from the sealing seat 29 of the inlet nozzle 12, transversely to the longitudinal direction.

[0084] The outer contour 24 of the guide element 21 forms an outer edge. The outer contour 24 of the inlet nozzle 12 forms the inner contour 25 of the passage 26 of the pipe bridge 18. Specifically, the inner contour 25 is a circular, in particular circular, inner circumference of the passage 26. The outer contour 24 of the guide element 21 is therefore formed in the shape of a circular arc. Specifically, the outer contour 24 of the guide element 21 forms a circular arc section. The outer contour 24 of the inlet nozzle 12 and the inner contour 24 of the passage 26 of the pipe bridge 18 have the same radius of curvature.

[0085] The outer contour 24 of the guide element 21 terminates at the inner wall with two ends, with an intermediate vertex arranged transversely to the longitudinal direction in the outlet opening 13. The outer contour 24 of the guide element 21 is therefore convexly curved.

[0086] The guide element 21 reduces the size of the outlet opening 13 of the inlet nozzle 12, since the guide element 21 projects with its outer contour 21 into the outlet opening transversely to the longitudinal direction of the nozzle 12. Due to the specially shaped outer contour 24 of the guide element 21, which corresponds to the adjacent inner contour 25 of the pipe bridge 18, an opening cross-section 23 of the outlet opening 13 of the inlet nozzle 12 is enlarged at the moment of the first flow entry from the inlet nozzle 12 into the passage 26 of the pipe bridge 18 during an opening process of the knife gate valve.

[0087] As in Fig. 4 and Fig. 5, the guide element 21 is designed such that, at the moment of the first flow entry from the inlet nozzle 12 into the pipe bridge 28, the opening cross-section 23 of the outlet opening 13 of the inlet nozzle 12 forms a cross-sectional shape that deviates from a point-shaped cross-section. This corresponds, for example, to an enlarged opening cross-section. At the moment of the first flow entry from the inlet nozzle 12 into the pipe bridge 18, the opening cross-section 23 is linear. At the moment of the first flow entry from the inlet nozzle into the passage 26 of the pipe bridge 18, the opening cross-section can have a passage area that encompasses a greater extent than a point-shaped opening. At the moment of the first flow entry from the inlet nozzle 12 into the passage 26 of the pipe bridge 18, the opening cross-section 23 forms a gap. The gap is arcuate. In other words, the gap is annular.Alternatively or additionally, the gap may be linear at least in sections.

[0088] The opening cross-section 23 of the outlet opening 13 of the inlet nozzle 12 is limited at the moment and during the entire opening process by an inner circumference of the inner wall 22 of the inlet nozzle 12, the outer contour 24 of the guide element 21, and the inner contour 25 of the passage 26 of the pipe bridge 18. In other words, the inner circumference of the inner wall 22 of the inlet nozzle 12, the outer contour 24 of the guide element 12, and the inner contour 25 of the passage 26 of the pipe bridge 18 define the size of the opening cross-section 23 of the outlet opening 13 of the inlet nozzle 12 into the pipe bridge 18 when the knife gate valve opens and closes.

[0089] The opening cross section 23 of the outlet opening 13 of the inlet nozzle 12 is always smaller than an opening cross section 31 of the inlet opening 15 of the outlet nozzle 14 when the knife gate valve 10 is opened and / or in the open position of the knife gate valve 10. This is exemplified in Fig. 3 can be seen.

[0090] The opening process of the knife gate valve 10 is described below according to Fig. 1 to 7.

[0091] When the locking device 16 is moved from the closed position to the open position of the knife gate valve 10, at the moment of an initial or first flow entry of a fluid flow into the passage 26 of the pipe bridge 18, a linear, in particular gap-shaped, opening cross-section 23 of the outlet opening 13 of the inlet nozzle 12 is released, which is defined by the outer contour 24 of the guide element 21 and the adjacent inner contour 25 of the passage 26 of the pipe bridge 18. Fig. 1, the knife gate valve 10 is shown in the closed position. In Fig. 4 and Fig. 5 shows the linear or gap-shaped opening cross-section 23 at the moment of the first flow entry of the fluid flow into the passage 26 of the pipe bridge 18.

[0092] Due to the larger opening cross-section 23 compared to a point-shaped opening, the particle-laden fluid flows distributed across the opening cross-section 23 into the passage 26 of the pipe bridge 18. This reduces the flow velocity of the fluid stream compared to a point-shaped opening. Furthermore, the guide element 21 in the inlet nozzle 12 releases the outlet opening 13 with a delay relative to the inlet opening 15 of the outlet nozzle 14, as shown in Fig. 3 or in the diagram according to Fig. 8 is clearly visible. In Fig. 8, curve K1 represents the area of ​​the opening cross-section 32 of the inlet opening 15 of the outlet nozzle 14 as a function of the stroke position of the blocking device 16 or the slide rod 36. Furthermore, curve K2 represents the area of ​​the opening cross-section 23 of the outlet opening 13 of the inlet nozzle 12 as a function of the stroke position of the blocking device 16 or the slide rod 36. It is clearly evident from this that at the moment of the first flow entry, a passage opening already exists from the passage 26 into the outlet nozzle 14. The delayed inflowing fluid flow is thus discharged through the opening cross-section 31 of the inlet opening 15 of the outlet nozzle 14 quickly and without placing excessive abrasive stress on the sealing seat 29 on the outlet nozzle 14.

[0093] During the further opening of the knife gate valve 10, which is Fig. 6 and Fig. 7 is shown as an example, the opening cross-section 23 is released continuously, in particular evenly.

[0094] The travel distance between the open position and the closed position, which the locking device 16 travels, for example, during the opening process, corresponds to a total stroke of the locking device 16, in particular of the slide rod 36. In the closed position, the locking device 16 is arranged at a minimum stroke position, and in the open position, the locking device 16 is arranged at a maximum stroke position. In other words, the locking device 16 has a stroke of 0 percent of the total stroke in the closed position and a stroke of 100 percent of the total stroke in the open position.

[0095] The stroke range in which the opening cross-section 23 of the outlet opening 13 of the inlet nozzle 12 influences an applied process pressure can range from 0 percent to 35 percent of the total stroke. This stroke range corresponds to the opening phase of the knife gate valve 10. The opening phase, in which the moment of first flow entry through the outlet opening 13 of the inlet nozzle 12 into the pipe bridge 18 occurs, can occur with a stroke of the blocking device 16 of 22 percent to 35 percent, in particular from 22 percent to 30 percent, of the total stroke. Preferably, the moment of first flow entry through the outlet opening 13 of the inlet nozzle 12 into the pipe bridge 18 occurs with a stroke of the blocking device 16 of 23 percent to 28 percent, in particular from 24 percent to 26 percent of the total stroke.Particularly preferably, the moment of the first flow entry through the outlet opening 13 of the inlet nozzle 12 into the pipe bridge 18 occurs at a stroke of 25 percent of the total stroke.

[0096] Fig. 9 and Fig. 10 show a further embodiment of a knife gate valve 10 according to the invention, which differs from the knife gate valve 10 according to Fig. 1 to 7 in the guide device 19 for flow guidance, specifically in the guide element, and the blocking device 16. In the following, only the different features of the knife gate valve 10 according to Fig. 9 and Fig. 10. All features of the knife gate valve 10 not described according to Fig. 9 and Fig. 10 are identical to those of the knife gate valve 10 according to Fig. 1 to 7 identical.

[0097] The knife gate valve 10 has a plurality of guide elements 21', which are arranged in a displacement direction of the blocking device 16 between the two shut-off plates 17 and the pipe bridge 18. The guide elements 21' each form a flow channel 32 transverse to the displacement direction, which connects the inlet nozzle 12 to the outlet nozzle 14, at least when the knife gate valve 10 is opened. The respective flow channel 32 penetrates the blocking device 16 transversely to the displacement direction of the blocking device 16. In other words, the respective flow channel 32 extends in the longitudinal direction of the inlet and outlet nozzles 12, 14. According to Fig. 9 and Fig. 10, the knife gate valve 10 has a total of two guide elements 21', each of which forms a flow channel 32.

[0098] The guide elements 21 are tubular. Specifically, the guide elements 21' are formed by pipe sections integrated into the barrier device 16. Alternatively, the guide elements 21' can be formed by profile pipe sections. The guide elements 21' extend parallel through the barrier device 16. The guide elements 21' are arranged on a common plane between the shut-off plates 17 and the pipe bridge 18.

[0099] As in Fig. 10, the guide elements 21' are arranged in the plate basket 34. This means that when the locking device 16 moves between the open and closed positions and vice versa, the guide elements 21' are moved along with the locking device 16. This has the advantage that when the knife gate valve 10 is opened, a fluid connection between the inlet and outlet ports 12, 14 is established before an opening cross-section 23 of the outlet opening 13 of the inlet port 12 is released into the passage 26 of the pipe bridge 18. This means that the fluid pressure on the inlet side is already reduced in advance, or the contamination deposited on the inlet side is fed through the flow channels to the outlet port 14. The guide elements 21' form bypass channels to the passage 26 of the pipe bridge 18, which divert the fluid flow from the inlet nozzle 12 into the outlet nozzle 14 during an opening process before the passage into the passage 26 of the pipe bridge 18 is released (see Fig. 9). As a result, the fluid flow through the passage 26 of the pipe bridge 18 contains fewer particles, so that the outlet-side housing sealing seat 29 is protected.

[0100] The embodiment according to Fig. 11 to 17 differs from the embodiment according to Fig. 1 to 7 only by the shape of the guide element 21 and by some detailed features of the guide element 21. All statements in connection with the embodiment according to Fig. 1 to 7 are therefore based on the embodiment according to Fig. 11 to 17 and are used in conjunction with the embodiment according to Fig. 11 to 17 discloses and claims.

[0101] In addition, the combination of the embodiments according to the Fig. 9, 10 and 11 to 17 discloses and claims.

[0102] As in the Fig. 11, Fig. 12, the knife gate valve 10 has a valve body 11 with an inlet nozzle 12. The inlet nozzle 12 defines an outlet opening 13, which is aligned with the inlet opening 15 of the corresponding outlet nozzle 14.

[0103] To operate the knife gate valve 10, a locking device 16 is provided, which comprises shut-off plates 17 and a pipe bridge 18. For details of the locking device 16, reference is made to the explanations in connection with the embodiment according to Fig. 1 to 7.

[0104] On the pipe bridge side, the inlet nozzle 12 has a guide device 19 with a guide element 21.

[0105] The difference to the guide element 21 according to Fig. 1 to 7 is that the outer contour 24 of the guide element 21 according to Fig. 11 to 15 forms a straight outer edge. It has been shown that the flow conditions in the initial phase of the opening of the knife gate valve are improved by the straight outer edge.

[0106] The geometry of the guide element 21 is described in more detail as follows. The straight outer edge extends, as in Fig. 12, practically on the same plane as the peripheral boundary of the exit opening 13. The straight outer edge runs essentially perpendicular to the opening and closing direction of the locking device 16. This is also shown in the schematic representation according to Fig. 15 clearly visible.

[0107] The surface of the guide element, the surface 28 of the guide element 21, is also straight, i.e. not curved.

[0108] Similar to the embodiment according to Fig. 1 to 7, the guide element 21 projects into the interior of the inlet nozzle 12. The surface 28 is arranged inclined relative to the inner wall of the inlet nozzle 12. The distance between the surface 28 and the inner wall of the inlet nozzle 12 increases continuously in the flow direction, ie in the direction of the outlet opening 13. This shape of the guide element 21 is well illustrated in cross-section according to Fig. 13. The distance of the surface 28 from the inner wall of the inlet nozzle 12 is maximum at the straight outer edge. This shape of the guide element 21 is clearly visible in the cross-section according to Fig. 13 can be seen.

[0109] As in Fig. 12, the outer contour 24 of the guide element 21, specifically the straight outer edge, is practically at the same height as the outlet opening 13. A slight gap between the shut-off plate 17 and the outer edge is possible, provided that the outlet opening 13 is shielded by the guide element 21 in such a way that a fluid flow in the initial phase of opening of the knife gate valve 10 is at least largely avoided.

[0110] Fig. 13, Fig. 14 show the triangular cross-section of the guide element 21. In the example according to Fig. 13, Fig. 14, the guide element 21 is made of solid material, i.e., it is massive. Alternatively, the guide element 21 can comprise a sheet metal that is connected to the inner wall of the inlet nozzle 12. In this case, the triangular cross-section is formed by the inner wall of the inlet nozzle 12 and the guide plate. The surface 28 is straight. Thus, the triangular cross-section of the guide element 21 extends across its entire width. The surface 28 has the same slope at all points.

[0111] In the Fig. 13, Fig. 14 shows a drainage gap 24 extending between the rear side of the guide element 21, i.e., on the side facing away from the surface 28, and the inner wall of the inlet nozzle 12. Liquid, such as condensate, can drain through the drainage gap 24.

[0112] To secure the guide element 21 in the inlet nozzle 12, a fastening means 45, for example in the form of a cam, is provided, which connects the guide element to the inlet nozzle 12 permanently or detachably. Other fastening means are possible. For example, the guide element 21 can be welded into the inlet nozzle. The cam is hook-shaped so that the guide element 21 can be placed onto it with a corresponding receiving opening. Other cam shapes are possible. For example, the cam can be straight for smaller nominal diameters.

[0113] The surface 28 is designed to be wear-resistant. For this purpose, for example, a hardfacing layer on the surface 28 can be provided by deposition welding.

[0114] The above-mentioned detailed features such as the drainage gap 44, the fastening means 45 and the armoring are also used in connection with the guide element according to Fig. 1 to 7 discloses and claims.

[0115] For 15 shows the shape of the opening cross-section 23 in the initial phase of opening, when the fluid connection between inlet nozzle 12 and outlet nozzle 14 is established and a portion of the through opening 26 of the pipe bridge 18 is released. As in Fig. As can be clearly seen in Figure 15, the opening cross-section 23 has a combined linear and arcuate shape. The opening cross-section 23 is formed as a circular segment-shaped gap. The straight side of the opening cross-section 23 (chord) is delimited by the straight outer edge of the outer contour 24. The arcuate side (circular arc) of the opening cross-section 23 is determined by the radius of curvature 27 of the pipe bridge 18.

[0116] As in the embodiment according to Fig. 1 to 7, the opening of the outlet opening 13 is delayed by the guide element 21 to such an extent that the inlet opening 15 of the outlet nozzle 14 is opened wider than the outlet opening 13 of the inlet nozzle 12 before the flow passage begins. Furthermore, the straight outer edge ensures that the opening cross-section is larger than in the prior art, thus reducing the undesirable nozzle effect in the initial opening phase.

[0117] In this embodiment, a small opening forms briefly as the inner wall of the plate basket 18 moves past the straight outer edge. However, the opening cross-section widens so rapidly as it continues to move past that a sufficiently large opening cross-section is provided, and the undesirable nozzle effect is practically suppressed. Furthermore, the inlet opening 15 of the outlet nozzle 14 is already relatively wide open before the outlet opening 13 of the inlet nozzle 12 is opened, so that the fluid penetrating the pipe bridge 18 is immediately discharged and cannot collect in the pipe bridge 18.

[0118] The particle flow in the initial phase of opening a knife gate valve constructed according to the prior art without the invention behaves in such a way that particles collect in the pipe bridge during opening and relatively few particles enter the outlet nozzle 14 at high speed from the pipe bridge 18. In comparison, fewer particles enter the pipe bridge 18 when a guide element 21 according to Fig. 11 to 15, which shields the outlet opening 13 of the inlet nozzle 12 in the initial phase. The particle flow can pass almost unhindered through the inlet opening 15, which is more open than the outlet opening 13.

[0119] The same phenomenon can be observed with the fluid flow, which builds up significantly in the pipe bridge in a knife gate valve without the invention. Due to the delay achieved in the embodiment according to the invention in opening the inlet opening 13 and the resulting different flow cross-sections, the fluid flow can pass through the opening barrier device 16 almost unhindered, even in the initial phase of opening.

[0120] Fig. 16, Fig. 17 show a curved plate guide element 46 on the inner wall of the pipe bridge 18. The plate guide element 46 is curved in the opposite direction to the inner wall of the pipe bridge located closer to the plate guide element 46. This results in an elliptical partial flow cross-section in the initial phase of opening (cf. Fig. 18).

[0121] The plate guide element 46 is firmly connected to the pipe bridge 18, in particular by means of a material bond, for example welded.

[0122] The plate guide element 46 extends in the flow direction, i.e., along the longitudinal axis of the pipe bridge 18, so that the particles flowing through the pipe bridge 18 are guided parallel to the longitudinal axis. In other words, the plate guide element is perpendicular to the shut-off plate 17 (cf. Fig. 17). As in Fig. 16, Fig. 17, the plate guide element 46 extends over the entire height of the pipe bridge 18 or the plate basket 34 and thus covers the entire distance between the inlet nozzle 12 and the outlet nozzle 14 (cf. Fig. 19).

[0123] The plate guide element 46 is arranged in a front region of the pipe bridge 18 in the opening direction. This allows the plate guide element 46 to reach the area of ​​the inlet nozzle 12 during the initial opening phase. The plate guide element 46 is arranged in the front half, in the opening direction, particularly in the front third of the pipe bridge 18. The exact arrangement depends on the desired dead time until the plate guide element reaches the area of ​​the inlet nozzle, or on the desired length of the edge segment of the outlet nozzle 14 that is to be covered or shielded by the plate guide element 46.

[0124] The operation of the plate guide element 46 is explained using the different valve or slide positions.

[0125] Fig. Figure 19 shows the slide position in the critical initial phase, when the pipe bridge 18 releases a partial flow cross-section. The plate guide element 46 limits the effective partial flow cross-section of the pipe bridge 18 in the radial direction, i.e., transversely to the longitudinal axis of the pipe bridge 18. Since the curvature of the plate guide element 46 corresponds to the curvature of the inner wall of the inlet nozzle 12 and the outlet nozzle 14, the plate guide element 46 is flush with the edges of the inlet nozzle 12 and the outlet nozzle 14 when the plate guide element 46 is moved into the area of ​​the inner wall of the inlet nozzle 12.

[0126] The plate guide element 46 of the pipe bridge 18 and the guide element 21 of the inlet nozzle 12 are arranged in the same circumferential section. In other words, the plate guide element 46 of the pipe bridge 18 and the guide element 21 of the inlet nozzle 12 are arranged on the same movement axis of the blocking device, so that both elements 46, 21 can interact during the initial opening phase. This applies to all embodiments and preferably also to the invention in general. This causes the plate guide element 46 to enter the flow shadow of the guide element 21, where it can deploy its erosion protection.

[0127] Fig. 20 shows the fully open state (maximum flow cross-section). Fig. 21 shows the closed or locked state.

[0128] Fig. Figure 22 relates to an alternative embodiment in which the plate guide element 46 is straight. Otherwise, the embodiment corresponds to the embodiment with a curved plate guide element 46. Fig. Figure 23 shows that the shielding effect is less complete than with the curved plate guide element 46. However, even this weaker shielding effect improves erosion protection at steep angles of repose.

[0129] It should be noted that the features of the described embodiments are not limited to the individual embodiments, but can be freely combined with one another. List of reference symbols 10 knife gate valves 11 valve housing 12 inlet nozzles 13 Exit opening 14 outlet nozzles 15 Entrance opening 16 Locking device 17 barrier plate 18 Pipe bridge 19 Guidance device 21 Guide element 21' additional guide element 22 Interior wall 23 Opening cross-section of the outlet opening of the inlet nozzle 24 Outer contour 25 inner contour 26 passage 27 radius of curvature 28 Surface 29 Sealing seat 31 Opening cross-section of the inlet opening of the outlet nozzle 32 flow channel 33 Pipe section 34 record basket 35 Spreader organ 36 slide rod 37 inner wedge 38 Outer wedge 39 Centering ball 41 Compensator unit 42 sealing rings 43 Compensator shaft 44 Drain gap 45 Fasteners (cam) 46 Plate guide element QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2022 105 939 A1 [0001, 0007] EP 0 450 646 A2

[0003] DE 10 2016 111 169 A1 [0005, 0006, 0012, 0047]

Claims

[1] Knife gate valve (10) for chemical and / or petrochemical industrial plants, comprising: - a slide valve housing (11) having an inlet nozzle (12) with an outlet opening (13) and an outlet nozzle (14) with an inlet opening (15), which correspond to one another in an open position of the knife gate valve (10); - a blocking device (16) with at least one shut-off plate (17) and a pipe bridge (18) which is movably arranged between the inlet and outlet nozzles (12, 14) for opening and closing the knife gate valve (10); and - at least one guide device (19) for flow guidance, wherein the guide device (19) has at least one guide element (21) which is arranged on an inner wall (22) of the inlet nozzle (12) and reduces the outlet opening (13) of the inlet nozzle (12) in such a way that when the knife gate valve (10) is opened, an opening cross-section (23) of the outlet opening (13) is enlarged at the moment of an initial, in particular first, flow entry into the pipe bridge (18), characterized by that the guide device (19) has at least one plate guide element (46) which is arranged on an inner wall of the pipe bridge (18) and extends in the flow direction. [2] Knife gate valve (10) according to claim 1, characterized by that the guide element (21) is designed such that when the knife gate valve (10) is opened, the outlet opening (13) of the inlet nozzle (12) can be released or is released with a delay in relation to the inlet opening (15) of the outlet nozzle (14). [3] Knife gate valve (10) according to one of the preceding claims, characterized by that the guide element (21) is adapted such that the opening cross-section at the moment of the first flow entry from the inlet nozzle (12) into the pipe bridge (18) forms at least one gap, in particular a gap extending in a plane with the shut-off plate (17), between the pipe bridge (18) and the inlet nozzle (12). [4] Knife gate valve (10) according to claim 3, characterized by that the guide element (21) is adapted such that the gap is arcuate in sections and linear in sections. [5] Knife gate valve (10) according to one of the preceding claims, characterized by that the guide element (21) has at least one outer contour (24) at the outlet opening (13) of the inlet nozzle (12), which extends transversely to the opening and closing direction of the knife gate valve (10). [6] Knife gate valve (10) according to one of the preceding claims, characterized by that the outer contour (24) has a straight, in particular horizontally arranged, or a curved outer edge. [7] Knife gate valve (10) according to one of the preceding claims, characterized by that the guide element (21) has a surface (28) which is straight and projects into the inlet nozzle (12) along the flow direction with increasing distance from the inner wall (22) or which, starting from the inner wall (22), curves into the interior of the inlet nozzle (12), in particular in a hump-like manner. [8] Knife gate valve (10) according to one of the preceding claims, characterized by that the guide element (21) has a triangular cross-section or forms a triangular cross-section together with the inner wall (22). [9] Knife gate valve (10) according to claim 8, characterized bythat the triangular cross-section extends along the width, in particular the entire width of the guide element (21). [10] Knife gate valve (10) according to one of the preceding claims, characterized by that a drainage gap (44) is formed between the guide element (21) and the inner wall (22). [11] Knife gate valve (10) according to one of claims 5 to 10, characterized by that the outer contour (24) extends inwards from the inner wall (22) transversely to the longitudinal direction of the inlet nozzle (12). [12] Knife gate valve (10) according to one of the preceding claims, characterized by that the guide element (21) is designed to rise in the flow direction towards the outlet opening (13) of the inlet nozzle (12). [13] Knife gate valve (10) according to one of the preceding claims, characterized bythat the guide element (21) extends at least partially in a longitudinal direction of the inlet nozzle (12) and ends at the outlet opening (13) of the inlet nozzle (12). [14] Knife gate valve (10) according to one of the preceding claims, in particular according to one of claims 3 to 10, characterized by that the inlet nozzle (12) and the outlet nozzle (14) each have a sealing seat (29) for the at least one shut-off plate (17), wherein the guide element (21), in particular the outer contour (24), is offset at least in sections from the sealing seat (29) of the outlet nozzle transversely to the longitudinal direction. [15] Knife gate valve (10) according to one of the preceding claims, characterized bythat an opening cross-section (31) of the inlet opening (15) of the outlet nozzle (14) is larger than the opening cross-section (23) of the outlet opening (13) of the inlet nozzle (12) when the knife gate valve (10) is opened and / or in the open position of the knife gate valve (10). [16] Knife gate valve (10) according to one of the preceding claims, characterized by in that the guide device (19) has a further guide element (21') which is arranged in a displacement direction of the blocking device (16) between the shut-off plate (17) and the pipe bridge (18), wherein the further guide element (21') forms a flow channel (32) transverse to the displacement direction, which at least when the knife gate valve (10) opens connects the inlet nozzle (12) to the outlet nozzle (14). [17] Knife gate valve (10) according to one of the preceding claims, characterized bythat the plate guide element (46) is arranged in a front region in the opening direction, in particular in the front half of the pipe bridge (18) in the opening direction. [18] Knife gate valve (10) according to one of the preceding claims, characterized by that the plate guide element (46) extends over the entire height of the pipe bridge (18). [19] Knife gate valve (10) according to one of the preceding claims, characterized by that the plate guide element (46) is curved or straight according to the curvature of the inlet nozzle (12).

Images