An asymmetric bidirectional sealing disc valve

Abstract

The present invention belongs to the field of pipeline engineering technology, and specifically relates to an asymmetric bidirectional sealing disc valve. It comprises an upper valve body 1, a lower valve body 2, a middle valve body 3, a valve stem 4, an upper valve seat 5, a lower valve seat 6, an upper valve disc 7, a lower valve disc 8, an upper disc spring assembly 9, a lower disc spring assembly 10, an upper ash retaining ring 11, a lower ash retaining ring 12, an upper bearing 13, and a lower bearing 14. The technical solution of the present invention has the beneficial effect of fully meeting the special process requirements of Ningmei furnaces, achieving reliable bidirectional sealing under given pressure differential conditions while also avoiding the potential impact of material accumulation on the valve. It can also be applied to other similar pulverized coal pressurized conveying devices.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline engineering, and in particular relates to a two-way sealing disc valve with an asymmetric structure. Background Art

[0002] Pulverized coal gasification technology is one method for converting raw coal into syngas. The basic process involves transferring ultra-fine, dry coal powder from a normal-pressure coal silo through a coal lock hopper to a high-pressure coal feed tank through a cycle of pressurization and depressurization. The feed tank continuously feeds the gasifier, where, under the action of oxidants such as oxygen and water, the coal is converted into syngas (CO + H2). The large vessels—the coal silo, coal lock hopper, and coal feed tank—are arranged from top to bottom on a framework. After the pulverized coal falls from the coal silo into the coal lock hopper by gravity, the inlet valve closes and pressurization begins. Once pressurization is complete, the equalization valve opens, and the outlet valve opens, allowing the pulverized coal to fall by gravity into the feed tank.

[0003] Under normal circumstances, the working pressure of the coal bunker is normal pressure, the feed tank is maintained at a high pressure state, and the pressure of the coal lock hopper alternates between normal pressure and high pressure. Its pressure will not exceed the pressure of the feed tank under interlock control. The sealing requirement of the coal lock hopper outlet valve is a one-way seal. In order to increase the reliability of the device, the coal lock hopper inlet valve and the coal lock hopper outlet valve are both set as double valves in series.

[0004] Furthermore, disc valves have gained widespread adoption as an alternative to metal-sealed ball valves in the pulverized coal pressurized conveying process. Due to the process requirements for one-way sealing, the coal lock hopper outlet valve is typically a single disc valve, with a single disc in the valve cavity, the sealing surface facing upward. This fully isolates the high-pressure feed tank from the lock hopper when the hopper is depressurized.

[0005] However, under certain abnormal operating conditions, such as improper manual operation, failure of the coal lock hopper pressure regulating valve, or failure of the coal lock hopper overpressure interlock, the lock hopper pressure may exceed the feed tank pressure and cause cross-pressure to flow into the feed tank, making it impossible to achieve absolute isolation between the two. However, the overpressure generally does not exceed 0.3MPa. Many processes either do not consider these extreme operating conditions or place excessive demands on valves, even requiring the valve to be bidirectionally sealed under full pressure differential. These requirements are not reasonable or do not conform to actual operating conditions.

[0006] As a gasification technology developed by integrating various domestic and international gasification technologies, the Ningmei furnace has put forward more scientific and reasonable requirements for the pressure differential between the coal lock hopper and the feed tank. The forward / reverse pressure differential from the coal lock hopper to the feed tank is required to be 0.3 / 6.2 MPa. This requirement not only takes into account abnormal operating conditions but also takes into account the actual operation of the device. If all single-disc valves are used, the disc spring force can only be greatly increased to meet the 0.3 MPa forward pressure differential, but this will lead to problems such as increased wear, bulky actuators, high energy consumption, and low reliability. If all conventional symmetrical double-disc valves are used, the accumulation of coal powder in the valve cavity may cause the valve to fail to open and close properly. In addition, connecting two two-way sealed valves in series can also cause pressure buildup and jamming. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to meet the special process requirements of Ningmei furnace. On the basis of the conventional double-disc valve, an asymmetric disc valve is designed. Its biggest feature is that the thickness of the two valve discs is set to be inconsistent, hoping to achieve the purpose of meeting the process requirements and ensuring smooth switching.

[0008] In order to achieve this purpose, the technical solution adopted by the present invention is:

[0009] An asymmetric bidirectional sealing disc valve comprises an upper valve body 1, a lower valve body 2, a middle valve body 3, a valve stem 4, an upper valve seat 5, a lower valve seat 6, an upper valve disc 7, a lower valve disc 8, an upper disc spring assembly 9, a lower disc spring assembly 10, an upper ash retaining ring 11, a lower ash retaining ring 12, an upper bearing 13, and a lower bearing 14;

[0010] Bolt holes evenly distributed along the circumference are provided on the upper valve body 1 and the lower valve body 2;

[0011] The middle valve body 3 is a cylindrical structure and is installed between the upper valve body 1 and the lower valve body 2. The upper valve body 1, the lower valve body 2 and the middle valve body 3 are connected together by a set of studs and nuts;

[0012] A through hole is formed on the upper valve body 1, and a blind hole is formed on the lower valve body 2. The valve stem 4 passes through the through hole on the upper valve body 1 and is inserted into the blind hole on the lower valve body 2. The valve stem 4 and the upper valve body 1 are fixed by the upper bearing 13, and the valve stem 4 and the lower valve body 2 are fixed by the lower bearing 14.

[0013] The upper valve seat 5 and the lower valve seat 6 are both stepped structures, and a welding groove is provided at the bottom for sealing after the valve is pressed into the upper valve body 1 and the lower valve body 2;

[0014] The valve stem 4 is welded together from three parts: the shaft inserted into the valve body 1, the cylindrical sleeve inserted into the upper valve disc 1, and the connecting plate connecting the shaft and the sleeve; blind holes are machined on both sides of the cylindrical sleeve, and disc spring guide columns are set in the blind holes;

[0015] The upper disc spring assembly 9 and the lower disc spring assembly 10 are respectively installed in the blind holes on both sides of the cylindrical sleeve in the valve stem 4;

[0016] The upper valve disc 7 and the lower valve disc 8 are respectively inserted into the cylindrical sleeve in the valve stem 4;

[0017] The upper disc spring assembly 9 and the lower disc spring assembly 10 provide initial sealing pre-tightening force for the upper valve disc 7 and the lower valve disc 8 respectively;

[0018] The upper ash retaining ring 11 and the lower ash retaining ring 12 are arranged in the grooves on the cylindrical sleeve to prevent coal powder from entering the upper disc spring group 9 and the lower disc spring group 10;

[0019] The actuator drives the valve stem 4 to rotate in the upper bearing 13 and the lower bearing 14, and at the same time drives the upper valve disc 7 and the lower valve disc 8 to slide freely on the upper valve body 1, the upper valve seat 5 and the lower valve body 2, the lower valve seat 6 respectively, to realize the opening and closing of the valve.

[0020] Furthermore, in the above-mentioned asymmetric bidirectional sealing disc valve, the actuator is driven in one of the following three ways: pneumatic, hydraulic, or electric.

[0021] Furthermore, in the above-mentioned asymmetric bidirectional sealing disc valve, the thickness of the upper valve disc 7 is 50-60 mm, and the width of the sealing surface is 20-30 mm.

[0022] Furthermore, in the above-mentioned asymmetric bidirectional sealing disc valve, the thickness of the lower valve disc 8 is 20-30 mm, and the width of the sealing surface is 10-12 mm.

[0023] Furthermore, in the asymmetric bidirectional sealing disc valve as described above, the disc spring force provided by the upper disc spring assembly 9 is 10,000 to 20,000 N.

[0024] Furthermore, in the asymmetric bidirectional sealing disc valve as described above, the disc spring force provided by the lower disc spring assembly 10 is 3000-5000N.

[0025] Furthermore, in the above-mentioned asymmetric bidirectional sealing disc valve, the sealing surface width of the upper valve seat 5 is 18 to 28 mm.

[0026] Furthermore, in the above-mentioned asymmetric bidirectional sealing disc valve, the sealing surface width of the lower valve seat 6 is 8 to 10 mm.

[0027] Furthermore, in the asymmetric bidirectional sealing disc valve as described above, gaps are set between the upper valve disc 7 and the lower valve disc 8 and the cylindrical sleeve in the valve stem 4 to ensure that the valve disc can slide freely on the upper valve body 1, upper valve seat 5 and lower valve body 2, lower valve seat 6 when the valve is opened and closed.

[0028] The beneficial effect of the technical solution of the present invention is that it can fully meet the special process requirements of Ningmei furnace, that is, it can achieve reliable two-way sealing under given pressure difference conditions, and avoid the possible impact of material accumulation on the valve. It can be applied to other similar pulverized coal pressurized conveying devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the valve setting of the Ningmei furnace pulverized coal pressure conveying device;

[0030] Figure 2 Schematic diagram of the asymmetric disc valve structure.

[0031] In the figure, 1-upper valve body, 2-lower valve body, 3-middle valve body, 4-valve stem, 5-upper valve seat, 6-lower valve seat, 7-upper valve disc, 8-lower valve disc, 9-upper disc spring assembly, 10-lower disc spring assembly, 11-upper ash ring, 12-lower ash ring 13-upper bearing 14-lower bearing. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Ningmei Furnace typically utilizes a combination of single-disc and double-disc valves. Two single-disc valves (1# and 2#) are installed at the coal lock hopper inlet, and one single-disc valve (3#) and one double-disc valve (4#) are installed at the coal lock hopper outlet, with the single-disc valve positioned on top. This invention relates to a special design for the 4# valve. Specifically, based on the 0.3 / 6.2 MPa pressure differential between the Ningmei Furnace's coal lock hopper and the coal feed tank, this invention modifies the conventional symmetrical disc valve structure. The inlet-side valve disc is designed as a thick disc, while the outlet-side valve is designed as a thin disc. Their strength and rigidity ensure that the seal is not affected by this pressure differential. The preload disc spring force and sealing surface dimensions are also designed to be different.

[0034] like Figure 1 The figure shows a common valve arrangement for a pulverized coal conveying system. To improve the reliability of tight isolation between containers, two tight shutoff valves are installed in series between the containers: coal lock hopper inlet valves (1#, 2#) and lock hopper outlet valves (3#, 4#). Except for valve 4, which uses the special structure proposed in this invention, all other valves can use single-disc valves.

[0035] like Figure 2 The figure shows a bidirectional sealing disc valve with a special structure provided by the present invention. To meet the special process requirements of Ningmei furnaces, its internal components are designed with an asymmetric structure. The asymmetry is mainly reflected in: the upper and lower valve discs 7 and 8 have different thicknesses and sealing surface sizes, the upper and lower disc spring assemblies 9 and 10 provide different disc spring forces, and the upper and lower valve seats 5 and 6 have different sealing surface sizes.

[0036] Specifically, the present invention provides an asymmetric bidirectional sealing disc valve, comprising an upper valve body 1, a lower valve body 2, a middle valve body 3, a valve stem 4, an upper valve seat 5, a lower valve seat 6, an upper valve disc 7, a lower valve disc 8, an upper disc spring assembly 9, a lower disc spring assembly 10, an upper ash ring 11, a lower ash ring 12, an upper bearing 13, and a lower bearing 14;

[0037] Bolt holes evenly distributed along the circumference are provided on the upper valve body 1 and the lower valve body 2;

[0038] The middle valve body 3 is a cylindrical structure and is installed between the upper valve body 1 and the lower valve body 2. The upper valve body 1, the lower valve body 2 and the middle valve body 3 are connected together by a set of studs and nuts;

[0039] A through hole is formed on the upper valve body 1, and a blind hole is formed on the lower valve body 2. The valve stem 4 passes through the through hole on the upper valve body 1 and is inserted into the blind hole on the lower valve body 2. The valve stem 4 and the upper valve body 1 are fixed by the upper bearing 13, and the valve stem 4 and the lower valve body 2 are fixed by the lower bearing 14.

[0040] The upper valve seat 5 and the lower valve seat 6 are both stepped structures, and a welding groove is provided at the bottom for sealing after the valve is pressed into the upper valve body 1 and the lower valve body 2;

[0041] The valve stem 4 is welded together from three parts: the shaft inserted into the valve body 1, the cylindrical sleeve inserted into the upper valve disc 1, and the connecting plate connecting the shaft and the sleeve; blind holes are machined on both sides of the cylindrical sleeve, and disc spring guide columns are set in the blind holes;

[0042] The upper disc spring assembly 9 and the lower disc spring assembly 10 are respectively installed in the blind holes on both sides of the cylindrical sleeve in the valve stem 4;

[0043] The upper valve disc 7 and the lower valve disc 8 are respectively inserted into the cylindrical sleeve in the valve stem 4;

[0044] There is a gap between the upper valve disc 7 and the lower valve disc 8 and the cylindrical sleeve in the valve stem 4 to ensure that the valve disc can slide freely on the upper valve body 1, upper valve seat 5 and lower valve body 2, lower valve seat 6 when the valve is opened or closed.

[0045] The upper disc spring assembly 9 and the lower disc spring assembly 10 provide initial sealing pre-tightening force for the upper valve disc 7 and the lower valve disc 8 respectively;

[0046] The upper ash retaining ring 11 and the lower ash retaining ring 12 are arranged in the grooves on the cylindrical sleeve to prevent coal powder from entering the upper disc spring group 9 and the lower disc spring group 10;

[0047] The actuator drives the valve stem 4 to rotate within the upper bearing 13 and lower bearing 14. This rotation simultaneously causes the upper valve disc 7 and lower valve disc 8 to slide freely on the upper valve body 1 and upper valve seat 5, and the lower valve body 2 and lower valve seat 6, respectively, to open and close the valve. In this embodiment, the actuator is driven by one of three methods: pneumatic, hydraulic, or electric.

[0048] exist Figure 2 In the illustrated embodiment, the valve is mounted vertically. When the valve is open, the medium flows from top to bottom. When the valve is closed, the pressure at the valve inlet, P1, is the lock hopper pressure, and the pressure at the valve outlet, P2, is the feed tank pressure, with a maximum value of 6.2 MPa. When P1 exceeds P2, the upper valve disc is pushed open, and the pressure in the valve cavity is P1. The upper valve disc is free of pressure, while the lower valve disc is subjected to a pressure differential ΔP = P1 - P2, typically less than 0.3 MPa. The pressure differential experienced by the lower valve disc is minimal, due to its small thickness. The sealing surfaces of the lower valve disc 8 and the lower valve seat 6 are relatively small, and the number of disc springs in the lower disc spring assembly 10 is relatively small. When the lock hopper releases pressure, P1 gradually decreases from 6.2 MPa to atmospheric pressure, and the pressure differential experienced by the upper valve disc 7 increases, reaching a maximum value of P1, 6.2 + 0.3 = 6.5 MPa. The significant pressure differential required by the upper valve disc 7 requires greater strength and rigidity, a wider sealing surface, and a greater initial preload. Therefore, the upper valve disc 7 is thicker, measuring 50-60 mm; the upper valve seat 5 has a wider sealing surface, measuring 18-28 mm; the upper disc spring assembly 9 includes a larger number of disc springs, providing a disc spring force of 10,000-20,000 N. Other specific parameters include the width of the upper valve disc 7's sealing surface being 20-30 mm; the lower valve disc 8 having a thickness of 20-30 mm and a sealing surface width of 10-12 mm; the lower disc spring assembly 10 providing a disc spring force of 3,000-5,000 N; and the sealing surface width of the lower valve seat 6 being 8-10 mm.

[0049] exist Figure 2 In the embodiment shown, the lower valve disc 8 is designed to be as thin as possible. In this way, even if ultrafine coal powder enters the valve cavity during the feeding process and accumulates to a certain extent, the sharp valve disc can still move freely between the accumulated coal powder, cutting and cleaning the coal powder blocks, so that the residual coal powder in the valve cavity is maintained at a low level and does not affect the opening and closing action of the valve.

Claims

1. An asymmetric bidirectional sealing disc valve, characterized by: It includes an upper valve body (1), a lower valve body (2), a middle valve body (3), a valve stem (4), an upper valve seat (5), a lower valve seat (6), an upper valve disc (7), a lower valve disc (8), an upper disc spring assembly (9), a lower disc spring assembly (10), an upper ash retaining ring (11), a lower ash retaining ring (12), an upper bearing (13), and a lower bearing (14); Bolt holes evenly distributed along the circumference are provided on the upper valve body (1) and the lower valve body (2); The middle valve body (3) is a cylindrical structure and is installed between the upper valve body (1) and the lower valve body (2). The upper valve body (1), the lower valve body (2) and the middle valve body (3) are connected together by a set of studs and nuts. The upper valve body (1) is provided with a through hole, the lower valve body (2) is provided with a blind hole, the valve stem (4) passes through the through hole of the upper valve body (1) and is inserted into the blind hole of the lower valve body (2), the valve stem (4) and the upper valve body (1) are fixed by an upper bearing (13), and the valve stem (4) and the lower valve body (2) are fixed by a lower bearing (14); The upper valve seat (5) and the lower valve seat (6) are both stepped structures, and a welding groove is provided at the bottom for sealing after the valve is pressed into the upper valve body (1) and the lower valve body (2); The valve stem (4) is welded together from three parts: a shaft inserted into the upper valve body (1), a cylindrical sleeve inserted into the upper valve disc (7), and a connecting plate connecting the shaft and the sleeve; blind holes are machined on both sides of the cylindrical sleeve, and disc spring guide columns are provided in the blind holes; The upper disc spring assembly (9) and the lower disc spring assembly (10) are respectively installed in the blind holes on both sides of the columnar sleeve in the valve stem (4); The upper valve disc (7) and the lower valve disc (8) are respectively inserted into the columnar sleeve of the valve stem (4); The upper disc spring assembly (9) and the lower disc spring assembly (10) provide initial sealing pre-tightening force for the upper valve disc (7) and the lower valve disc (8) respectively; The upper ash retaining ring (11) and the lower ash retaining ring (12) are arranged in the grooves on the cylindrical sleeve to prevent coal powder from entering the upper disc spring assembly (9) and the lower disc spring assembly (10); The actuator drives the valve stem (4) to rotate in the upper bearing (13) and the lower bearing (14), and at the same time drives the upper valve disc (7) and the lower valve disc (8) to slide freely on the upper valve body (1), the upper valve seat (5) and the lower valve body (2), the lower valve seat (6), respectively, to realize the opening and closing of the valve; The thickness of the upper valve disc (7) is 50 to 60 mm, and the width of the sealing surface is 20 to 30 mm; The thickness of the lower valve disc (8) is 20 to 30 mm, and the width of the sealing surface is 10 to 12 mm; The disc spring force provided by the upper disc spring assembly (9) is 10000~20000N; The disc spring force provided by the lower disc spring assembly (10) is 3000-5000N; The sealing surface width of the upper valve seat (5) is 18 to 28 mm; The sealing surface width of the lower valve seat (6) is 8 to 10 mm; A gap is provided between the upper valve disc (7) and the lower valve disc (8) and the columnar sleeve in the valve stem (4) to ensure that the valve disc can slide freely on the upper valve body (1), the upper valve seat (5) and the lower valve body (2), the lower valve seat (6) when the valve is opened or closed.

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