Gate valve

Abstract

The invention refers to a gate valve comprising a body (1) with an operational through-opening (5), cover (2) and closing disc (8) including solid disc engaged in worm gear crown with contact surfaces. The closing disk is provided with an O-ring pressed by segment flange comprising four identical separate segments. The gate further comprises two guides (20) with C-shaped cross-sections, solid lower bases with central bores closed by support plates (23), and support surfaces forming angle. There are worm screws (25) in the guides. Orientation brackets (31) lying on orientation slots are engaged in orientation grooves. Worm screws are engaged in the teeth of the worm gear crown and the support surfaces contact the contact surfaces. Upper ends of the worm screws pass through upper bores in the cover and have drive elements (11) fixed thereto.

Description

[0001] GATE VALVE

[0002] FIELD OF INVENTION

[0003] The invention refers to a gate valve for high pressure fluids (above 100 bar) and finds application in pipeline systems for conveying natural gas, oil and other fluids.

[0004] PRIOR ART

[0005] There are various known designs of gate valves for high pressure fluids including a body hermetically closed with a cover, an operational through- opening in the body, a closing element, an operational seal and a drive element. The replacement of the worn operational seal needs the gate valve be completely disassembled and then reassembled, and requires skilled personnel, specialised equipment and transportation to equipped work areas. This extends the time and makes maintenance of the gate valve more expensive. In addition, known gate valves have relatively large dimensions in relation to the diameter of the pipeline which further complicates the servicing and maintenance. Many of the known gate valves cannot be manually operated in case of larger pipeline diameters and high pressures of 140 - 150 bar because of the increased friction during movement of the closing element as a result of the increased weight of the valve and the high pressure on the closing element.

[0006] CN 206874854 U discloses a gate valve having a corpus with a vertical axis of symmetry provided with a closing plate and a lead screw connected thereto by a radial-axial bearing joint. The corpus includes a body and a flat cover closing hermetically the body by bolted joints and a seal in the contact zone between the body and the cover. In the lower part of the body there is an operational through- opening of circular cross-section arranged perpendicular to the vertical axis of the corpus. Flanges are provided on the outer sides of the operational through-opening for connection to the pipeline system. On the inside of the operational through- opening there is a respective radial groove in which rests a respective operational seal. The lead screw passes through a threaded hole in the cover and above said threaded hole there is a sealing element pressed by a clamping flange. The top of the lead screw is engaged in a worm gear crown so that the lead screw moves linearly along the vertical axis of the gatevalve. The worm gear crown is engaged in a worm drive screw at the end of which a drive wheel is mounted. The rotation of the drive wheel transmits a rotary motion to the lead screw which moves linearly along the vertical axis together with the closing plate linked to it. In the top dead position of the lead screw the operational through-opening is fully open and the fluid flows freely through the valve. In the bottom dead position the closing plate completely closes the operational through- opening. The fluid pressure presses the closing plate against the operational seal around the operational through- opening and cuts off the access of the fluid. The worm gear allows easy manual operation of the gate valve even in cases of large diameters and high fluid pressures. However, the height of the gate valve is very large - more than seven times the diameter of the pipeline which makes installation, servicing and maintenance difficult and makes the gate valve unsuitable for use in multi-level pipeline systems and pipelines with large diameters. In addition, the replacement of the operational seal of this gate valve is a slow and complex process requiring highly skilled personnel, transport and equipped industrial premises as the valve must be completely disassembled, the closing plate removed and the operational seal replaced, then reassembled and transported back. This makes the repair and maintenance of the gate valve longer and more expensive.

[0007] DESCRIPTION OF INVENTION

[0008] It is the object of the present invention to provide a compact and easy to operate and maintain gate valve for high pressure fluids which allows easy and quick replacement of the operational seal on site with no need to transport the gate valve to specially equipped industrial premises where it can be completely disassembled, and which allows manual operation also in case of large pipeline diameters and high fluid pressures, and which is also applicable to multi-level pipeline systems.

[0009] The task is solved by providing a gate valve having a corpus with a vertical axis of symmetry Y in which a closing disc with a centre C is located. The corpus includes a body and a ribbed cover in which a cavity with the profile of the closing disc is provided. The cover is hermetically attached to the body by bolted joints and a contact seal in the form of at least one sealing ring lying in a respective face groove around thebody opening. In the lower part of the body there is an operational through- opening with a circular cross-section of radius r and with a longitudinal axis X intersecting at right angle the vertical axis Y. The outer sides of the operational through- opening are provided with end flanges with end holes therein for connection to the pipeline system. The closing disc comprises a solid disc on which a worm gear crown is fixed. At the outer ends of the worm gear crown there are contact surfaces arranged at an angle 0, where 0 is between 100° and 150°. In each face of the solid disc there is a radial groove with blind threaded holes arranged concentrically at a uniform pitch. At the outer end of the radial groove there is an operational seal in the form of an O-ring of radius R>r which is clamped by a segment flange attached to the solid disc by mounting screws passing through mounting holes in the segment flange and screwed into the blind threaded holes in the radial groove. The segment flange consists of four identical separate segments. Symmetrically on each side of the operational through-opening there is a guide with a cylindrical body with a C-shaped cross-section, a solid lower base with a central bore closed from bellow detachably by a support plate. The guide has longitudinal support surfaces forming an angle 0, and at the upper end of the guide there is a bearing housing. In each guide there is a worm screw with a radial bearing fixed to its upper end, said radial bearing lying in the respective bearing housing in the guide. The lower end of the worm screw rests on a support plate closing the central bore from below which acts as a support bearing. In the upper part of the body there are orientation slots in which orientation brackets lie. The orientation bracket is engaged in a corresponding orientation groove provided on the outer side of each guide. The guides are fixed to the body by the orientation brackets, so that the two worm screws are engaged in the teeth of the worm gear crown and the support surfaces contact the contact surfaces. The upper end of the worm screw passes through a corresponding upper bore in the cover and exits the corpus. The upper bores in the cover are sealed in a known manner by a sealing element. To the upper end of each worm screw a drive element is fixed by means of which the closing disc can be moved linearly along the axis Y and also can be rotated around its axis.

[0010] Preferably, the drive element is a hexagonal bushing.Preferably, the sealing element is a sealing sleeve with outer and inner sealing members arranged along the outer and inner contact diameters of the sealing sleeve. This allows the sealing members to be changed without the need to disassemble the gate valve.

[0011] Preferably, the contact seal is designed as two sealing rings lying in respective face grooves around the body opening in the upper face of the body.

[0012] There may be transport lugs in the upper and lower part of the corpus for suspension and easy installation, uninstallation and transportation.

[0013] The gate valve according to the invention is compact, reliable and easy to operate and maintain. It does not require highly skilled personnel and specialized equipment for maintenance. The operational seals can be easily and quickly changed on site without the valve having to be disassembled or transported to specially equipped industrial premises. The gate valve according to the invention has a relatively small height - less than three times the pipeline diameter which facilitates service and maintenance and makes it suitable also for use in pipelines with large diameters and in multi-level pipeline systems. It can be driven by only one drive element, thus increasing its reliability. The worm gear also allows manual drive also in cases of large pipeline diameters and high fluid pressure, without the use of a mechanical reducer. All this reduces the time and cost of servicing and maintenance of the proposed valve and makes it universally applicable in high pressure pipeline systems.

[0014] EXPLANATION OF THE FIGURES

[0015] Fig. 1. Axonometric half- view-half- section of a preferred embodiment of a gate valve; Fig. 2. Assembling scheme of the gate valve;

[0016] Fig. 3a. Front view of the closing disc;

[0017] Fig. 3b. A cross section along A-A of figure 3a).

[0018] Fig. 4. Assembling scheme of the closing disc;

[0019] Fig. 5. Eongitudinal half- section of the guide with a worm screw in it;

[0020] Fig. 6a. Eongitudinal section of the guide;Fig. 6b. A cross section along A-A of fig. 6a;

[0021] Fig. 7. Detail view A of fig. 2.

[0022] Fig. 8. Axonometric half- view-half- section of the cover;

[0023] Fig. 9. Detail view A of fig. 1.

[0024] Fig. 10. Axonometric half- view-half- section of the sealing sleeve;

[0025] Fig. Ila. Longitudinal section of the gate valve in the bottom dead position;

[0026] Fig. 1 lb. Longitudinal section of gate valve in the top dead position;

[0027] Fig. 11c. Front view of a gate valve in a position of changing the operational seal. EXEMPLARY EMBODIMENTS OF THE INVENTION

[0028] Figures 1 - 11c elucidate a preferred embodiment of a gate valve according to the invention. It is a corpus with a vertical axis of symmetry Y in which is arranged a closing element designed as a closing disc 8 with a centre C. The corpus includes a prismatic body 1 and a ribbed cover 2 in which a cavity is formed with the profile of the closing disc 8. The cover is fixed to the body by bolted joints 3. In this exemplary embodiment, the cover is fixed to the body by connecting bolts passing through connecting holes on the periphery of the cover 2 and screwed into corresponding connecting threaded holes in the upper face of the body 1 as shown in figure 1. The contact seal in this embodiment is designed as two sealing rings 4 lying in respective face grooves 33 arranged concentrically around the body opening in the upper face of the body 1. In the lower part of the body 1 there is an operational through- opening 5 having a circular cross-section with radius r and with a longitudinal axis X perpendicular to the axis Y. On both outer sides of the operational through- opening 5 there are end flanges 6 with end holes 7 provided therein for connection to the pipeline system. The closing disc 8 is symmetrical and comprises a solid disc 13 on which a worm gear crown 10 is fixed, said worm gear crown 10 is secured against slippage by locking screws 38. On both sides of the worm gear crown 10 there are contact surfaces 12 arranged at an angle 0 which in this embodiment is 120°. Radial grooves 14 are provided in the faces of the solid disc 13 in which blind threaded holes 18 are arranged at a uniform pitch. At the outer end of the radial grooves 14 there is an operational sealin the form of an O-ring of radius R>r fixed to the solid disc 13 by mounting screws 16 passing through mounting holes 17 in the segment flange 15 and screwed into the blind threaded holes 18. The segment flange 15 consists of four identical separate segments 19. Symmetrically on both sides of the operational through- opening 5 there is a guide with a cylindrical body with a C-shaped cross-section and a solid lower base 21. In the lower base 21 there is a central bore 22 closed from below by a support plate 23 and a lower screw 41. The guide 20 has support surfaces 24 forming an angle 0=120°. In each guide 20 there is a worm screw 25 with a radial bearing 26 packed in its upper end. The lower end of the worm screw 25 rests on the support plate 23 in the central bore 22, which acts as a support bearing, and the radial bearing 26 lies in a bearing housing 27 formed in the upper end of the guide 20. The upper end of the worm screw 25 passes through a corresponding upper bore 28 in the cover 2. The upper bores 28 are sealed with a corresponding sealing element 29 which in this exemplary embodiment is a sealing sleeve with outer and inner sealing members 36 and 37 arranged along the outer and inner contact diameters of the sealing sleeve, respectively. The sealing sleeve 29 is fixed in the upper bore 28 by fastening bolts 39 screwed into the cover 2. A drive element 11 is mounted to the upper end of the worm screw 25. In this exemplary embodiment, the drive element is a hexagonal drive bushing fixed to the worm screw 25 by means of two keys 34 and two stop screws 35. An orientation bracket 31 resting on an orientation slot 32 at the upper end of the body 1 is engaged in an orientation groove 30 provided on the outer side of the guide 20. The guides 20 are fixed to the body 1 by the orientation brackets 31, so that the two worm screws 25 are engaged in the teeth of the worm gear crown 10 and the support surfaces 24 contact the contact surfaces 12.

[0029] At the upper end of the cover 2 and at the lower end of the body 1 there are two transport lugs 40 each for suspending and carrying the gate valve during installation and maintenance.

[0030] METHOD OF OPERATION

[0031] The gate valve is mounted to the pipeline system in a known manner by means of the end flanges 6 on the outer sides of the operational through- opening 5. The regulationof the fluid flow is carried out by rotation of the drive bushings 11 which impart rotary motion to the respective worm screws 25. The mechanism of work is elucidated in figures 1, Ila, 11b and 11c. When rotating of one or both drive bushings 11 in the same direction the closing disc 8 is moving up or down along the axis Y. When rotating to the right the closing disc 8 moves downwards and when rotating to the left it moves up. In the bottom dead (closed) position the centre C of the closing disc 8 lies on the axis X and fully closes the operational through-opening 5 (figure Ila). Under the fluid pressure the closing disc 8 presses tightly to the opposite side of the body 1 and the corresponding operational seal 9 closes hermetically that side of the operational through- opening 5. In the top dead position the upper part of the closing disc 8 enters the cavity of the cover 2 whereby the operational through- opening 5 remains fully open and the fluid flows freely through the gate valve (figure 1 lb).

[0032] When the two worm screws 25 are rotated uniformly in opposite directions the closing disc 8 performs a rotary motion about its axis without moving linearly along the axis

[0033] When necessary to replace the operational seal 9 the gate valve is removed from the pipeline system whereupon by rotating one or both of the drive bushings 11 the closing disc 8 is so positioned that one of the segments 19 of the segment flange 15 is located entirely in the operational through- opening 5 (figure 11c). The mounting screws 16 are unscrewed through the operational through- opening 5, the corresponding segment 19 is removed, the corresponding part of the worn out operational seal 9 in this sector is removed and the corresponding part of the new operational seal is applied in its place after which the corresponding segment 19 is reinstalled.

[0034] The drive bushings 11 are then rotated in opposite directions so that the closing disc 8 is rotated a quarter turn and the next segment 19 of the segment flange 15 is positioned opposite the operational through- opening 5 and is fully accessible therethrough. The procedure is repeated until the operational seal 9 on the respective side of the closing disc 8 is completely replaced. The operational seal 9 on the other side of the closing disc 8 is replaced in a same way.

Claims

CLAIMSA gate valve having a corpus with a vertical axis Y comprising a body (1) hermetically closed with a cover (2) by bolted joints (3) and a contact seal (4) located in respective face groove (33), an operational through-opening (5) with a circular cross-section of radius r and longitudinal axis X intersecting at right angle the axis Y provided in the lower part of the body (1), said operational through-opening (5) provided with end flanges (6) with end holes (7), the gate valve further comprising a closing element, an operational seal (9), a worm gear crown (10) and a drive element (11), wherein on both sides of the worm gear crown (10) there are contact surfaces (12) arranged at an angle 0, where 0 is between 100° and 150°, and the closing element is a closing disc (8) comprising a solid disc (13) on which the worm gear crown (10) is fixed, and the operational seal (9) is an O-ring of radius R>r located at the outer end of a radial groove (14) in the respective face of the solid disc (13) and clamped by a segment flange (15) mounted to the solid disc (13) by mounting screws (16) passing through mounting holes (17) in the segment flange (15) and screwed into blind threaded holes (18) in the radial grooves (14), and the segment flange (15) comprises four identical separate segments (19), and the cover (2) is ribbed and within said cover (2) there is a cavity with the profile of the closing disc (8), and symmetrically on each side of the operational through-opening (5) there is a guide (20) having a cylindrical body with a C-shaped cross-section, a solid lower base (21) with a central bore (22) closed from below detachably by a support plate (23), and support surfaces (24) forming an angle 0, where a worm screw (25) with a radial bearing (26) packed in the upper end is placed in the guide (20), the lower end of said worm screw (25) lying on the support plate (23) in the central bore (22), the radial bearing (26) lying in a respective bearing housing (27) formed in the upper end of the respective guide (20), and the upper end of the worm screw (25) passing through a corresponding upper bore (28) in the cover (2), said upper bore (28) provided with a sealing element (29), and on the outer side of the guide (20) there is an orientation groove (30) in which an orientation bracket (31) is engaged, and the guides (20) are fixed to the body (2) by said orientation brackets (31) lying on a respective orientation slots (32) at the upper end of the body (1), so that the worm screws (25) are engaged in the teeth of the worm gear crown (10) and thesupport surfaces (24) contact the contact surfaces (12), and where the drive element (11) is fixed to the upper end of the respective worm screw (25).

2. A gate valve according to claim 1, wherein the drive element (11) is a drive bushing.

3. A gate valve according to claim 2, wherein the drive bushing (11) is fixed to the upper end of the respective worm screw (25) by means of keys (34) and stop screws (35).

4. A gate valve according to claims 1 to 3, wherein the contact seal (4) is at least one sealing ring lying in a respective face groove (33) in the upper face of the body (1).

5. A gate valve according to claims 1 to 4, wherein the sealing element (29) is a sealing sleeve with outer and inner sealing members (36) and (37) arranged along the outer and inner contact diameters of the sealing sleeve, respectively.

6. A gate valve according to claims 1 to 5, wherein there are two transport lugs (40) each at the top of the cover (2) and at the lower part of the body (1).

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