Gate valve
The gate valve design with trapezoidal cutouts and stellite-coated guides effectively addresses wear and corrosion issues by uniformly removing catalyst particles, enhancing the valve's durability and efficiency in catalytic cracking units.
Patent Information
- Authority / Receiving Office
- RU · RU
- Patent Type
- Utility models
- Current Assignee / Owner
- NOT PUBLISHED
- Filing Date
- 2025-10-16
- Publication Date
- 2026-06-30
AI Technical Summary
Existing gate valves in catalytic cracking units suffer from wear and corrosion due to the accumulation of abrasive catalyst particles on the guides, leading to frequent repairs and reduced efficiency.
The gate valve design features trapezoidal cutouts with fillets and/or chamfers in the guide surfaces, coated with stellite, to efficiently remove catalyst particles and prevent accumulation, with a preferred angle of 50° to 70° convergence and dimensions of 10-15 mm depth and 75-140 mm pitch.
The design enhances wear resistance and service life by ensuring uniform catalyst flow and distribution, reducing wear and corrosion, thereby increasing the reliability and throughput of the gate valve.
Smart Images
Figure 00000001_ABST
Abstract
Description
[0001] Field of technology to which the utility model belongs
[0002] The utility model relates to the field of oil refining, in particular to a gate valve for catalytic cracking units.
[0003] Technology Level
[0004] Gate valves are used to regulate the flow of feedstock, catalyst, and other process fluids during the cracking process. During operation of gate valves in catalytic cracking units, their guides are exposed to aggressive environments. Gate discs (dampers) and guides are subject to high temperature loads and wear due to the impact of solid particles.
[0005] A known gate valve for a catalyst (patent RU 9286, published 16.02.1999), comprising a housing with an inlet and outlet pipe, a gate valve placed in the housing with the possibility of reciprocating movement in guides inclined to the axis of the passage channel of the gate valve and kinematically connected to a drive fixed on the housing, characterized in that the gate valve console is made in the form of a semi-ellipse, the central axis of which in the closed position of the gate valve coincides with the axis of the passage channel, and the width of the semi-ellipse is less than the width of the gate valve, and on the bottom plate of the guides a groove is made in the form of a semi-ellipse, equidistant and opposite to the semi-ellipse of the gate valve console.
[0006] A gate valve with welded internal components (US Patent 6,050,288, published April 18, 2000) is known, which is the closest analogue. The design objective is to protect critical sliding surfaces from flow and erosion. This is achieved by using a stellite overlay and positioning individual valve components away from the flow path through the valve. The gate valve comprises guides in the form of L-shaped plates with an upper, lower, front, rear, and two lateral surfaces. On the front side, a shelf-shaped protrusion is formed, forming a supporting surface for the gate and an adjacent front surface, on which triangular cross-sectional cutouts are made, extending from the supporting surface of the protrusion to the underside of the guide.
[0007] A drawback of existing technical solutions is the accumulation of abrasive particles on the surface of the catalyst guides during operation of the gate valve. This leads to corrosion of the metal, leading to wear of the device, the need for more frequent repairs, and reduced efficiency in aggressive environments. In the prototype, the protective Stellite coating does not cover the guides at the corners of the cutouts, thus further increasing the damage. Furthermore, the triangular shape of the cutouts promotes cracks and damage due to corrosion, particularly in the corners. This necessitates frequent replacement or repair of the guides, which are susceptible to damage during operation in aggressive environments.
[0008] The technical challenge is to create a gate valve design that reduces wear due to the accumulation of catalyst and abrasive particles.
[0009] The technical result consists in increasing the wear resistance and service life of the gate valve guides due to more efficient removal of catalyst particles from the surface of the guides.
[0010] Disclosure of the essence of the utility model
[0011] A gate valve comprises a housing; a diaphragm inside the housing, containing a diaphragm opening defining an internal flow section; gate guides installed inside the housing opposite each other near the diaphragm opening; a gate configured to slide in a reciprocating motion along the gate guides parallel to the cross-section of the diaphragm opening for selectively opening and closing the diaphragm opening; wherein each gate guide comprises a front, rear, upper, lower and two side sides, wherein a protrusion in the form of a shelf is formed on the front side, forming a support surface for interaction with the gate and a front surface bordering it, wherein cutouts are formed on the front surface of the protrusion, oriented in the direction from the support surface to the lower side of the guide.The technical problem is solved, and the technical result is achieved by the fact that the guide cutouts have a trapezoidal cross-section, the larger base of which coincides with the specified front surface of the protrusion.
[0012] The guide cutouts contain fillets and / or chamfers along the cross-sectional contour.
[0013] The cross-section of the guide cutouts is an isosceles trapezoid, the sides of which converge at an angle of 50° to 70°.
[0014] The guide cutouts are made with a depth of 10 mm to 15 mm and are located along the length of the guides in increments of 75 mm to 140 mm.
[0015] The top and front sides of the guides, including the cutout surfaces, are coated with stellite.
[0016] Brief description of drawings
[0017] Fig. 1 shows a top view of a gate valve in a perspective view.
[0018] Fig. 2 shows a bottom axonometric view in section of a gate valve.
[0019] Fig. 3 shows the bottom view of the valve module.
[0020] Fig. 4 shows a sectional view A-A of Fig. 2 of the valve module.
[0021] Fig. 5 shows a bottom view of the gate valve guide.
[0022] Fig. 6 shows a perspective view from below of the gate valve guide.
[0023] Fig. 7 shows the profile of the guide cutout in detail.
[0024] The figures indicate the following positions:
[0025] 1 - body; 1.1 - guide cone; 1.2 - diaphragm; 2 - connecting truss; 3 - drive; 4 - damper; 5, 6 - guide; 7 - front side of the guide; 8 - rear side of the guide; 9 - upper side of the guide; 10 - lower side of the guide; 11 - sides of the guide; 12 - supporting surface of the protrusion; 13 - front surface of the protrusion; 14 - cutouts; 15 - mounting holes.
[0026] Implementation of a utility model
[0027] The gate valve (Fig. 1, 2) is a part of the catalytic cracking unit. The gate valve comprises a housing 1, a connecting frame 2 and a drive 3. The housing 1 defines a gate chamber with an inlet zone and an outlet zone, a support cone 1.1 located in the inlet zone, tapering towards the outlet zone. The support cone 1.1 is attached to the housing 1 at its inlet end. At the outlet end of the support cone 1.1, a diaphragm 1.2 is located with an opening defining the maximum internal flow area of the gate valve. The diaphragm 1.2 is a plate attached to the support cone 1.1 and / or the walls of the housing 1, for example, using bolted connections.
[0028] To ensure selective opening and closing of the diaphragm opening 1.2, a gate valve module (Fig. 2-4) is located in the housing 1, consisting of a gate valve 4 (plate) and guides 5, 6. Gate valve 4 is configured to reciprocate along guides 5, 6 parallel to the cross-section of the diaphragm opening 1.2. Gate valve 4 is fixed on a drive rod, which extends outside the housing 1 and is connected through a connecting truss 2 to a drive 3 with the possibility of setting it in motion to control the position of gate valve 4. In the fully open position, gate valve 4 does not block the opening of diaphragm 1.2, to maximize the flow of medium through the gate valve chamber. In the fully closed position, gate valve 4 completely blocks the opening of diaphragm 1.2, to minimize the flow of medium through the gate valve chamber. In addition, the gate valve 4 can take many intermediate positions between the fully open and fully closed positions for precise adjustment of the flow of the medium through the valve chamber.
[0029] The guide 5, 6 of the gate valve (Fig. 2-6) is made, as a rule, in the form of an L-profile plate with a length l, width w and height h (see Fig. 6). The guide 5, 6 of the gate valve comprises a front side 7, a rear side 8 (not visible in Fig. 6, conventionally shown by the dotted line 8), an upper side 9 (not visible in Fig. 6, conventionally shown by the dotted line 9), a lower side 10 and two side sides 11. On the front side 7 there is a projection in the form of a shelf, which forms a supporting surface 12 (not visible in Fig. 6, conventionally shown by the dotted line 12) for the gate valve 4 and a front surface 13 bordering it. Thus, the gate valve 4 rests on the supporting surfaces 12 of the guides, and during the operation of the gate valve, the gate valve 4 slides along the supporting surfaces 12. On the front surface 13 of the projection there are cutouts 14, oriented in the direction from the supporting surface 12 of the projection to the lower side 10 of the guide, in other words, oriented along the height h of the guide.The cutouts 14 have a trapezoid shape in cross-section, the larger base of which coincides with the front surface 13 of the projection (see Fig. 3, 5, 7), i.e. the cutouts 14 narrow from the front surface 13 into the depth of the projection of the guide 5, 6.
[0030] Guides 5, 6 are attached to the gate valve body 1, specifically to the support cone 1.1, using bolts passing vertically through through mounting holes 15 made in guides 5, 6, which is a standard method. Gate 4 has mating surfaces with which it rests on the supporting surfaces 12 of the projections of guides 5, 6.
[0031] When the guides 5, 6 are secured to the support cone 1.1, the contact of the guide 5, 6 with the support cone 1.1 occurs through the upper side 9 of the guide 5, 6. The working surface of the guide 5, 6, which contacts the catalyst in the flow of the substance, is the support surface 12 of the protrusion, formed by a shelf from the L-shaped section profile and facing the flow of the catalyst, i.e., to the support cone 1.1 and onto which the cutouts 14 extend.
[0032] The cross-section of the cutouts 14 is preferably shaped like an isosceles trapezoid. The angle B of convergence of the trapezoid's lateral sides in the cross-section of the cutouts is preferably selected in the range of 50° to 70°, most preferably 60°. The cutouts preferably include roundings or chamfers along the cross-sectional contour. These preferred geometric parameters of the cutouts were determined during the simulation of the gate valve operation as the most effective in terms of preventing the accumulation of catalyst particles on the guide surfaces.
[0033] Guides 5, 6 are preferably made of wear-resistant materials, in particular wear-resistant steel 12Kh18N10T or 30KhGSA with a coating (for example, based on stellite) to withstand the abrasive effect of the catalyst.
[0034] The gate valve works as follows.
[0035] The notches 14 are located on the front surface 13 of the projection of the guide 5, 6 and extend from the supporting surface of the projection of the guide 5, 6 to the lower side 10 of the guide 5, 6 to ensure the gravity drainage of the catalyst. The gate 4 (valve) is moved manually or by means of the drive 3, creating a passage for the catalyst particles. When the gate 4 is opened, the catalyst particles, under the action of pressure and gravity, begin to move through the notches 14 in the guides 5, 6, made in the shape of trapezoids. The notches 14 are designed to prevent the catalyst from accumulating and blocking the movement of the gate 4. The specified shape of the notches 14, compared to the triangular shape of the notches in the prototype, ensures uniform and controlled movement of the catalyst flow in the open position of the gate 4, and also allows for the uniform distribution of the stellite surfacing over the surface of the notches 14, eliminating unprotected areas.
[0036] After passing through the gate valve and slots 14 in guides 5 and 6, the catalyst is typically sent to a collection bin for temporary storage before being transported by pneumatic transport or conveyor to the regeneration or disposal area and, if the catalyst requires recovery, to the regeneration unit. Once the discharge is complete, the gate valve closes, preventing further catalyst spillage.
[0037] The size of the notches 14 is determined by the characteristics of the catalyst (particularly the particle size) and the required discharge rate. Guides 5, 6 and the notches 14 are made of wear-resistant materials (such as coated steel or ceramic) to withstand the abrasive action of the catalyst.
[0038] The presence of roundings and chamfers facilitates the entry of catalyst and abrasive particles into the cutouts 14 and prevents their accumulation on the surface of the guides. This solution also eliminates the appearance of corners that are not protected by the Stellite overlay and can act as stress concentrators.
[0039] The pitch and depth of the cutouts 14 are selected experimentally to ensure effective removal of catalyst particles with minimal impact on the device's strength. The guide's throughput and efficiency depend on the catalyst type (particle size, density, and abrasiveness) and operating conditions (gate valve bore diameter, length and width of guides 5 and 6, pressure, temperature, and flow velocity). Increasing the pitch and depth of the cutouts 14 increases the throughput, but excessively large cutouts 14 may cause clogging or uneven flow.
[0040] The pitch A of the arrangement of the cutouts 14 on the surface of the guides from 75 mm to 140 mm and the depth of the cutouts B from 10 mm to 15 mm are selected for the gate valve where the diameter of the body 1 varies from 900 mm to 2000 mm, in the catalytic cracking unit with a catalyst with a particle size of 0.5-2 mm.
[0041] The achievement of the technical result is confirmed by experimental data and theoretical calculations.
[0042] Tests were conducted on an industrial unit with a catalyst with a particle size of 0.5-2 mm. With a cutout pitch of 95 mm and a depth B of 12 mm, a throughput of 700 kg / h with an efficiency of 90% was achieved. Calculations from hydrodynamics and granular flow theory were used. It was found that a cutout pitch of 95 mm and a depth B of 12 mm provide an optimal balance between throughput and clogging prevention.
[0043] With values less than the minimum (cutout pitch less than 75 mm or cutout depth less than 10 mm), the throughput capacity decreases and the likelihood of catalyst particles accumulating on the guide surface and clogging due to narrow cutouts increases. For example, with a cutout pitch of 70 mm and a depth of 8 mm, the throughput capacity drops to 400 kg / h, and the efficiency drops to 75%. The catalyst becomes stuck in the cutouts, causing the process to stop.
[0044] With values greater than the maximum (cutout pitch greater than 140 mm or depth greater than 15 mm), uneven catalyst flow occurs, wear on the guides increases, and the likelihood of catalyst spillage outside the collection bin increases. For example, with a cutout pitch of 150 mm and a depth of 16 mm, throughput increases to 1200 kg / h, but efficiency decreases to 80% due to uneven flow and increased wear. Furthermore, cutout depths greater than 15 mm are not possible due to closely spaced mounting holes.
[0045] Applying a stellite (a cast hard material based on cobalt and chromium) coating to the guide further increases the structure's resistance to aggressive environments, especially when exposed to high temperatures, due to the well-known properties of this material.
[0046] Thus, the utility model increases the service life of gate valve guides (and, consequently, the reliability of the gate valve as a whole) by effectively removing catalyst and abrasive particles from the guide surface. This makes the solution industrially applicable, particularly in gate valves for catalytic cracking units, where handling aggressive media and catalysts is required.
Claims
1. A gate valve comprising a housing; a diaphragm within the housing containing a diaphragm opening defining an internal flow area; gate guides mounted inside the housing opposite each other near the diaphragm opening; a gate configured to slide reciprocatingly along the gate guides parallel to the cross-section of the diaphragm opening for selectively opening and closing the diaphragm opening;wherein each slide gate guide comprises a front, rear, upper, lower and two side sides, wherein on the front side a projection is made in the form of a shelf, forming a supporting surface for interaction with the slide gate and a front surface bordering it, wherein on the front surface of the projection cutouts are made, oriented in the direction from the supporting surface to the lower side of the guide, characterized in that the cutouts of the guides have a cross-section in the form of a trapezoid, the larger base of which coincides with the said front surface of the projection.
2. A gate valve according to paragraph 1, characterized in that the cutouts of the guides contain roundings and / or chamfers along the contour of the cross-section.
3. A gate valve according to claim 1, characterized in that the cutouts of the guides have a cross-sectional shape of an isosceles trapezoid, the lateral sides of which converge at an angle of 50° to 70°.
4. A gate valve according to paragraph 1, characterized in that the cutouts in the guides are made with a depth of 10 mm to 15 mm and are located along the length of the guides in increments of 75 mm to 140 mm.
5. A gate valve according to any one of paragraphs 1-4, characterized in that a stellite coating is applied to the upper and front sides of the guides, including the surfaces of the cutouts.