Knife gate valve
Patent Information
- Application Number
- EP2023790232
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-10-11
- Filing Date
- 2023-10-11
- Publication Date
- 2025-08-20
AI Technical Summary
Existing knife gate valves face issues such as decreased spring effect leading to leaks, precise adjustment requirements for sealing ring distance, potential blocking due to external forces and temperature-related material expansion, and high operational forces due to central wedge systems, resulting in weight and leakage issues.
A knife gate valve design featuring a pressure system with a guide tube and pressure tube that can be displaced relative to each other, allowing radial pressing of the slide plate against the sealing seat, enabling direct contact pressure application to the sealing surface, and utilizing rotational movements to increase contact force, ensuring a reliable seal even under high temperatures and pressures.
This design achieves a significantly better seal with a metal-to-metal fit, reduces the thickness and weight of the slide plates, and maintains reliability under critical conditions, including wear and high pressures, while preventing leaks and operational difficulties.
Smart Images
Figure 1.1
Abstract
Description
[0001] DESCRIPTION
[0002] Knife gate valve
[0003] The invention relates to a knife gate valve with at least one movable gate plate.
[0004] Knife gate valves with one or two gate valves are used to shut off lines in industrial plants such as the chemical and petrochemical industries, steelworks and power generation plants.
[0005] Single and double-knife gate valves with different solutions for pressing and releasing the sealing elements are known from the state of the art.
[0006] In single-plate gate valves, such as those known from DE 102017 108 576 A1, the sealing system is clamped by a defined number of spring elements that permanently press the sealing rings against the gate plate, or by shims installed between the nozzle and the body. The number and thickness of the shims must be precisely determined so that the preload can be adjusted to ensure sufficient contact pressure on the sealing rings.
[0007] In double-plate gate valves, such as those known from DE 102015 104 555 A1, DE 2827 170 A1 or EP 0 326 787 A1, the gate plates are pressed together by a wedge-in-wedge system acting centrally between the plates, which is brought into engagement via the spindle or gate rod and presses the plates against the sealing rings.
[0008] Both solutions have the following technical disadvantages.
[0009] When the spring action decreases, the spring elements no longer apply the required contact pressure to the sealing system and the slide valve becomes leaky.
[0010] The distance between the sealing rings and the gate valve must be adjusted with the utmost precision to ensure the valve's proper function and tightness. Additional forces acting on the valve via the pipeline can cause the valve to jam, making it impossible to operate.
[0011] Likewise, temperature-related material expansion during operation often leads to blocking of the end plate, making operation difficult or even impossible.
[0012] Due to the strong preload of the sealing system, high forces are required to operate the gate valve. The actuators must be dimensioned accordingly.
[0013] In the double-plate gate valve, the plates are pressed against the sealing seats via a centrally acting wedge system.
[0014] This results in the following disadvantages:
[0015] In order to transfer the wedge forces to the entire sealing surface in the seat area outside the center of the slide passage, the plates must be very solid or massively reinforced in the middle, which results in the plates being very heavy.
[0016] Since the contact pressure is applied centrally and not directly in the seating area of the sealing rings, the end plates can partially lift off when pressure is applied, which also leads to leaks.
[0017] US 2,664,9018 A relates to a seal for drain control. The drain control comprises a tubular body having a main portion which has a plate chamber extending transversely to the body and an elongated, radially disposed access channel. The seal has a clamp slidably inserted into the inner end of the body to engage the plate. The clamp is actuated relative to the body by screwing means. The screwing means includes an annular member located entirely within the body and threaded onto the clamp, having a toothing on its outer surface between its end portions, two rolling bearing means spaced apart on the outer surface of the member and arranged at opposite end portions thereof, and which are arranged at opposite end portions of the member and retain the member within the body for rotation relative thereto.The link is operated by a gear.
[0018] GB 171 082 A discloses a high-pressure gate valve with parallel vapor-tight surfaces. The gate valve is closed and opened by raising and lowering locking discs. For sealing, internally threaded nuts, screwed onto stud bolts, engage the threaded recesses of the locking discs, so that when these nuts are rotated in opposite directions, the locking discs are moved away from or toward each other. The locking discs are also connected to the parts that control axial displacement and raising and lowering in such a way that they can rotate freely independently of these parts.
[0019] DE 270221 A describes a gate valve. The gate valve comprises closure plates that can be set into simultaneous longitudinal and rotational movement by engaging a valve spindle with teeth arranged on the back of the closure plates.
[0020] GB 273187 A relates to a lock valve. The lock valve has locking discs that can be pressed onto opposing valve seats by means of a screw-like gear.
[0021] The object of the present invention is to provide a knife gate valve that avoids the aforementioned disadvantages of existing knife gate valves.
[0022] This object is achieved according to the invention by a flap valve which has a pressing system which comprises a guide tube and a pressing tube which are displaceable relative to one another, wherein the at least one slide plate can be pressed radially against the sealing seat via the pressing tube, wherein the guide tube and the pressing tube are rotatable relative to one another for transmitting a rotational movement.
[0023] The required contact pressure is applied radially to the sealing surface via the guide tube and the pressure tube.
[0024] The sealing surfaces are pressed directly into the annular sealing section. This results in significantly improved sealing. The ability to move the guide and pressure tubes beyond their predefined end positions, thus increasing the contact pressure, allows for reliable sealing with a purely metallic seal seat, even under critical operating conditions at high temperatures and high pressures. This also applies in the event of wear on the sealing surfaces. The thickness of the gate valves is simply selected based on the prevailing pressure and temperature conditions. This allows them to be considerably thinner and lighter than existing knife gate valves.
[0025] An advantageous embodiment of the invention consists in that an axially actuable hollow spindle is provided which does not rotate during the movement, in the end of which a polygon is mounted in an axially sliding manner, on which a gear is arranged, via which the guide tube can be rotated, wherein the rotational movement of the guide tube can be transferred to the pressure tube, wherein the polygon is a square or a hexagon.
[0026] By rotating the hollow spindle with the polygon and the gear mounted on it, the guide tube can be driven by the meshing counter-toothing. The rotational movement of the guide tube can be translated into an axial displacement of the pressure tube until the set end position is reached and the slide plates are radially pressed against the sealing ring.
[0027] An alternative embodiment of the invention consists in that an axially actuable push rod is provided which does not rotate during the movement, at the end of which a push head is mounted in an axially sliding manner, via which a link can be actuated, via which the guide tube can be rotated, wherein the rotational movement of the guide tube can be transferred to the pressure tube.
[0028] By moving the push rod with the push head (66) and the gate mounted on it, the guide tube can be driven. The rotational movement of the guide tube is transferred into an axial movement of the pressure tube until the set end position is reached and the slide plates are radially pressed in the area of the sealing rings.
[0029] A further advantageous embodiment of the invention is that the pressure tube can be moved by rotating the guide tube.
[0030] The invention also provides for a trapezoidal thread to transmit the rotational movement of the guide tube to the pressure tube. The rotational movement of the guide tube can be transmitted to the pressure tube by means of a trapezoidal thread, causing the pressure tube to move axially until the set end position is reached and the slide plates are pressed radially. A further embodiment of the invention consists in providing at least two inclined support surfaces to transmit the rotational movement of the guide tube to the pressure tube.
[0031] The at least two inclined support surfaces can be arranged at the end of the guide tube facing the pressure tube. If the end of the pressure tube facing the guide tube has corresponding inclined support surfaces, the pressure tube is displaced during the rotational movement of the guide tube, whereby the at least one slide plate is pressed radially against the sealing set. The inclined support surfaces can be wedge-shaped.
[0032] The design with inclined support surfaces allows the knife gate valve to be used advantageously for pipes with large diameters.
[0033] It is provided within the scope of the invention that the guide tube and the pressure tube are sealed against each other by means of a sealing means towards the interior of the slide.
[0034] Furthermore, it is advantageous that at least one protective plate is provided to prevent the direct flow of medium onto the square as well as the gear wheel and the space between the slide plates.
[0035] Embodiments of the invention are described below with reference to drawings.
[0036] It shows
[0037] Fig. 1a, 1b, 1c, 1d and 1e show a double-plate gate valve according to the invention in
[0038] Side view, a section AA, a detail view B, a section DD and a detail view C.
[0039] Fig. 2 shows another double-plate gate valve according to the invention in
[0040] partial section,
[0041] Fig. 3a, 3b, 3c show a double-plate gate valve in and 3d side view, a section AA, a section BB and a detailed view C Fig. 1a to 1e show a plate gate valve according to the invention.
[0042] The knife gate valve comprises a housing (1) closed by a housing cover (3). A nozzle (2) is connected to the housing (1). On the side of the nozzle (2) opposite the housing (1) is a hood (4), to which a gear column (5) with a drive flange (6) is attached. A retaining bracket (9) for the handwheel drive is arranged on this drive flange (6). This bracket supports the corresponding handwheel (32), which is secured by a clamping nut (34).
[0043] A hollow spindle (10) extends from the handwheel (32) over the retaining bracket (9) and through the gear column (5) to the hood (4). A square (15) (or a hexagon) is axially slidingly mounted in the lower end of the hollow spindle (10), onto which a gear (14) is mounted. A guide tube (24) is driven by a rotary movement of the spindle (10) and can transmit its rotary movement via a trapezoidal thread to a pressure tube (23) on the slide plates (18).
[0044] The slide plates (18) are attached to the lower end of the hollow spindle (10) via retaining tabs (19) and extend through the hood (4), the nozzle (2) and the housing (1).
[0045] The movement of the slide plate(s) (18) from OPEN to CLOSED and vice versa is carried out via the axially actuated hollow spindle (10), which does not rotate during the movement.
[0046] To press and release the sealing system (sealing ring 20 and slide plate 18), the movable pressure pipe (23) is moved in the opposite direction by rotating the guide pipe (24).
[0047] For this purpose, the guide tube (24) is driven by means of the mating toothing via a rotary movement of the spindle (10) with the square (15) and the gear (14) mounted thereon. The guide tube (24) transmits its rotational movement to the pressure tube (23) via a trapezoidal thread, displacing it axially until the set end position is reached and the slide plates (18) are radially pressed in the area of the sealing rings (20). The axially displaceable mounting of the pressure tube (23) enables simultaneous pressing in both directions and is therefore also applicable to the variant with two end plates.
[0048] The guide tube (24) and pressure tube (23) are sealed from each other to the interior of the valve by packing rings (26 and 27) in order to prevent the penetration of medium into the trapezoidal thread of the guide tube (24) and pressure tube (23) and to ensure trouble-free operation even in heavily contaminated media.
[0049] The protective plates (21 and 22) prevent the medium from flowing directly onto the square (15), the gear (14), and the gap between the slide plates (18) when the slide plates (18) are moved to their respective end positions. Depending on the type of slide valve, one or two protective plates (21 and 22) are installed.
[0050] Fig. 2 shows another knife gate valve according to the invention. Identical features are assigned the same reference numerals.
[0051] The knife gate valve comprises a housing (1) closed by a housing cover (3). A nozzle (2) is connected to the housing (1). On the side of the nozzle (2) opposite the housing (1) is a hood (4), to which a gear column (5) with a drive flange (6) is attached. A retaining bracket (9) for the handwheel drive is arranged on this drive flange (6). This bracket supports the corresponding handwheel (32), which is secured by a clamping nut (34).
[0052] A hollow spindle (10) extends from the handwheel (32) over the retaining bracket (9) and through the gear column (5) into the hood (4). A square (15) (or a hexagon) is axially slidingly mounted in the lower end of the hollow spindle (10), onto which a gear (14) is mounted. A guide tube (24) is driven by a rotary movement of the spindle (10) and can transmit its rotary movement via at least two inclined support surfaces (54) into an axial movement of the pressure tube (23) against the slide plates (18). The at least two inclined support surfaces (54) are arranged on the end of the guide tube (24) facing the pressure tube (23). The end of the pressure tube (23) facing the guide tube (24) has corresponding inclined support surfaces, so that the pressure tube (23) is displaced during the rotational movement of the guide tube (24).
[0053] The slide plates (18) are attached to the lower end of the hollow spindle (10) via retaining tabs (19) and extend through the hood (4), the nozzle (2) and the housing (1) (not shown).
[0054] The sliding plate(s) (18) are moved from OPEN to CLOSED and vice versa via the axially actuated hollow spindle (10), which does not rotate during movement. To press and release the sealing system (sealing ring 20 and sliding plate 18), the movable pressure tube (23) is moved by rotating the guide tube (24).
[0055] For this purpose, the guide tube (24) is driven by means of the mating toothing via a rotary movement of the spindle (10) with the square (15) and the gear (14) mounted thereon. This translates its rotational movement into an axial movement of the pressure tube (23) via the at least two inclined support surfaces (54) until the set end position is reached and the slide plates (18) are radially pressed in the area of the sealing rings (20). The axially displaceable mounting of the pressure tube (23) enables simultaneous pressing in both directions and is therefore also applicable to the variant with two end plates.
[0056] The guide tube (24) and pressure tube (23) are sealed from each other to the interior of the valve by packing rings (26 and 27) in order to prevent the penetration of medium into the trapezoidal thread of the guide tube (24) and pressure tube (23) and to ensure trouble-free operation even in heavily contaminated media.
[0057] The protective plates (21 and 22) prevent the medium from flowing directly onto the square (15), the gear (14), and the gap between the slide plates (18) when the slide plates (18) are moved to their respective end positions. Depending on the type of slide valve, one or two protective plates (21 and 22) are installed.
[0058] Fig. 3a to 3d show another knife gate valve according to the invention.
[0059] The knife gate valve comprises a housing (1) closed by a housing cover (3). A nozzle (2) is connected to the housing (1). On one side of the housing (1) is a gear column (5) with a bevel gear (56). A handwheel drive with a corresponding handwheel (32) is mounted on this bevel gear.
[0060] A push rod (62), which does not rotate during travel, can be axially actuated via the handwheel (32). A push head (66) is mounted axially sliding at one end of the push rod (62). A slotted link (55) connected to the guide tube (24) can be actuated via the push head. The guide tube (24) is rotated by the axial movement of the push rod. The slide plates (18) extend through the hood (4), the nozzle (2), and the housing (1).
[0061] The movement of the slide plate(s) (18) from OPEN to CLOSED and vice versa is carried out via the axially actuated push rod (62) which does not rotate during movement.
[0062] To press and release the sealing system (sealing ring 20 and slide plate 18), the movable pressure pipe (23) is moved in the opposite direction by rotating the guide pipe (24).
[0063] For this purpose, the guide tube (24) is driven by moving the push rod (62) with the push head (66) and the link (55) mounted thereon. The guide tube (24) transmits its rotational movement to the pressure tube (23) by means of a trapezoidal thread and displaces the latter in the axial direction until the set end position is reached and the slide plates (18) are pressed radially in the area of the sealing rings (20). Alternatively, at least two inclined support surfaces can be provided to transmit the rotational movement of the guide tube (24) to the pressure tube (23). The axially displaceable mounting of the pressure tube (23) enables simultaneous pressing in both directions and is therefore also applicable to the variant with two end plates.
[0064] The guide tube (24) and pressure tube (23) are sealed from each other to the interior of the valve by packing rings (26 and 27) in order to prevent the penetration of medium into the trapezoidal thread of the guide tube (24) and pressure tube (23) and to ensure trouble-free operation even in heavily contaminated media.
[0065] The protective plates (21 and 22) prevent direct flow into the space between the slide plates (18) when the slide plates (18) are moved to their respective end positions. Depending on the type of slide valve, one or two protective plates (21 and 22) are installed.
[0066] List of reference symbols:
[0067] 1 housing
[0068] 2 nozzles
[0069] 3 housing cover
[0070] 4 hood
[0071] 5 column drive flange
[0072] 7 spindle nut
[0073] 8 Retaining ring
[0074] 9 support brackets
[0075] 10 hollow spindle
[0076] 11 Flanged bushing
[0077] 12 gland
[0078] 13 Packing ring
[0079] 14 gear
[0080] 15 square
[0081] 16 axle holders
[0082] 17 T raverse
[0083] 18 Slide plate
[0084] 19 Retaining tab
[0085] 20 sealing ring
[0086] 21 mudguard
[0087] 22 mudguard
[0088] 23 Pressure pipe
[0089] 24 guide tube
[0090] 25 Seal
[0091] 26 packing ring
[0092] 27 Packing ring
[0093] 28 Seal
[0094] 29 Drive
[0095] 30 tooth coupling
[0096] 31 Gearbox cover
[0097] 32 Handwheel
[0098] 33 Handwheel
[0099] 34 clamping nut
[0100] 35 key
[0101] 36 key
[0102] 37 Shield
[0103] 38 Shield
[0104] 39 Pointer Press-Release
[0105] 40 Adjusting ring
[0106] 41 Washer 42 Screw plug
[0107] 43 threaded pin
[0108] 44 Logo
[0109] 45 hexagon screw
[0110] 46 hexagon screw
[0111] 47 Hexagon screw
[0112] 48 hexagon screw
[0113] 49 Hexagon screw
[0114] 50 hexagon screw
[0115] 51 hexagon screw
[0116] 52 hexagon screw
[0117] 53 Hexagon nut
[0118] 54 inclined support surface
[0119] 55 backdrop
[0120] 56 bevel gears
[0121] 57 threaded bushing
[0122] 58 threaded bushing
[0123] 59 spindle
[0124] 60 cylindrical pin
[0125] 61 Suspension slide plate
[0126] 62 push rod
[0127] 63 guide bolts
[0128] 64 DU socket
[0129] 65 cylindrical pin
[0130] 66 Push head
[0131] 67 Stud screw
[0132] 68 hexagon nut
[0133] 69 packing ring
[0134] 70 flange bushing
[0135] 71 threaded pin
[0136] 72 bolts
[0137] 73 Washer
[0138] 74 Seal
Claims
CLAIMS 1. Knife gate valve with at least one movable gate plate (18), characterized in that the knife gate valve has a pressure system which comprises a guide tube (24) and a pressure tube (23) which are displaceable relative to one another, wherein the at least one gate plate (18) can be pressed radially against the sealing seat via the pressure tube (23), wherein the guide tube (24) and the pressure tube (23) are rotatable relative to one another for transmitting a rotational movement.
2. Knife gate valve according to claim 1, characterized in that an axially actuable hollow spindle (10) is provided which does not rotate during movement, in the end of which a polygon (15) is mounted in an axially sliding manner, on which a gear (14) is arranged, via which the guide tube (24) can be rotated, wherein the rotational movement of the guide tube (24) can be transferred to the pressure tube (23) and wherein the polygon (15) is a square or a hexagon.
3. Knife gate valve according to claim 1, characterized in that an axially actuable push rod (62) is provided which does not rotate during movement, at the end of which a push head (66) is mounted in an axially sliding manner, via which a link (55) can be actuated, via which the guide tube (24) can be rotated, the rotational movement of the guide tube (24) being transferable to the pressure tube (23).
4. Knife gate valve according to one of claims 1 to 3, characterized in that the pressure pipe (23) can be moved by a rotation of the guide pipe (24).
5. Knife gate valve according to one of claims 1 to 4, characterized in that a trapezoidal thread is provided for transmitting the rotational movement of the guide tube (24) to the pressure tube (23).
6. Knife gate valve according to one of claims 1 to 4, characterized in that at least two inclined support surfaces are provided for transmitting the rotational movement of the guide tube (24) to the pressure tube (23).
7. Knife gate valve according to one of claims 1 to 6, characterized in that the guide tube (24) and the pressure tube (23) are sealed against each other by sealing means towards the interior of the gate valve. Knife gate valve according to one of claims 1 to 7, characterized in that at least one protective plate (21, 22) is provided to prevent the direct flow of medium onto the square as well as the gear wheel (14) and the space between the gate plates (18).