Sealing structure for small reactor once-through steam generator

Abstract

The invention discloses a sealing structure for a once-through steam generator of a small reactor, relates to the technical field of sealing of pressure vessels, and solves the problems that the sealing structure of the once-through steam generator of the small reactor is prone to sealing failure and leakage and difficult to maintain. The device comprises an end socket, a water inlet connecting pipe and a pipe plate, wherein the end socket sleeves the water inlet connecting pipe and is connected with the pipe plate; a groove structure is arranged at one end of the water inlet connecting pipe, a first sealing groove is formed in the pipe plate, the groove structure is inserted into the first sealing groove, and a sealing ring is arranged between the groove structure and the first sealing groove; the groove structure is a right trapezoid groove, the sealing ring is a D-like sealing ring, and the inclined inner wall of the groove structure makes contact with the inclined face of the sealing ring. By means of the sealing ring structure in a special shape and the groove structure, pressing force borne by the sealing ring is decomposed into force in the vertical direction and force in the horizontal direction, and the sealing effect can still be guaranteed when the water inlet connecting pipe displaces or rebounds.

Description

Technical Field

[0001] The invention relates to the technical field of pressure vessel sealing, in particular to a sealing structure for a small reactor once-through steam generator. Background Art

[0002] Small reactors are increasingly used in the field of nuclear-powered ships due to their small size, high flexibility and good safety. Direct-current steam generators are used to convert the heat energy generated by the reactor into steam to drive steam turbines to generate electricity.

[0003] However, due to its small size, small reactor steam generators bring some problems, one of which is the difficulty in maintenance and repair.

[0004] The cold side medium of the existing direct current steam generator enters the heat exchange tube from the upper part of the equipment, drops to the bottom of the heat exchange tube and then returns to the upper part. Therefore, the upper pipe box of the equipment needs to have two chambers on the inlet side and the outlet side. These two chambers are generally formed by welding and cannot be disassembled. After searching, such as a U-shaped double-walled heat transfer tube direct current steam generator with a publication number of CN114543556A, a direct current steam generator with a publication number of CN107274946A, a multi-unit tubular direct current steam generator with a publication number of CN107143833A, and a lead-bismuth pile direct current steam generator with a publication number of CN115440401B all adopt such a structure.

[0005] Once the heat exchange tubes of the above steam generators leak or become clogged, it will be difficult to replace and repair them. Using a detachable sealing structure instead of the original welded structure can solve the maintenance problem, but the operating conditions of the small reactor direct current steam generator are relatively complex, with high operating temperatures and pressures, and the existing sealing structure is prone to sealing failure and leakage.

[0006] In summary, in order to meet the maintenance and overhaul requirements of small reactor direct current steam generators, developing an innovative high-performance sealing structure has become a technical problem that needs to be urgently solved in the current nuclear energy field. Summary of the invention

[0007] In order to solve the above-mentioned problems that the sealing structure of the existing small reactor direct current steam generator is prone to sealing failure, leakage and maintenance difficulties, the present invention proposes a sealing structure for a small reactor direct current steam generator. The present invention decomposes the pressing force on the sealing ring into vertical force and horizontal force by setting a special shape of the sealing ring structure and the groove structure, and can still ensure the sealing effect when the water inlet pipe is displaced or rebounds.

[0008] The present invention proposes a sealing structure for a small reactor direct current steam generator, which specifically comprises a head, a water inlet pipe and a tube sheet, wherein the head is sleeved on the water inlet pipe and connected to the tube sheet; a groove structure is provided at one end of the water inlet pipe, a sealing groove 1 is provided on the tube sheet, the groove structure is inserted into the sealing groove 1, and a sealing ring is provided between the groove structure and the sealing groove 1.

[0009] Furthermore, the cross-sectional shape of the groove inside the groove structure is a right-angled trapezoid; the long bottom side of the right-angled trapezoid is the groove opening, and the inner wall of the hypotenuse is in contact with the sealing ring.

[0010] Furthermore, the angle between the inner wall of the hypotenuse of the groove structure and the vertical direction is 28 degrees.

[0011] Furthermore, circular grooves are provided on the inner wall of the oblique side of the groove structure and at the corners of the bottom of the groove.

[0012] Furthermore, the upper half of the cross-sectional shape of the sealing ring is a right-angled trapezoid, and the lower half is a semicircle, and the hypotenuse of the right-angled trapezoid contacts the hypotenuse inner wall inside the groove structure.

[0013] Furthermore, the angle between the hypotenuse of the right-angled trapezoidal part of the sealing ring and the vertical direction is 30 degrees.

[0014] Furthermore, the head and the tube plate are both provided with a second sealing groove, and an octagonal gasket is provided in the second sealing groove.

[0015] Furthermore, the second sealing groove is a trapezoidal groove.

[0016] Furthermore, the first sealing groove is a rectangular groove.

[0017] Furthermore, a steam outlet pipe is provided on the sealing head.

[0018] The sealing structure for a small reactor once-through steam generator according to the present invention has the following beneficial effects:

[0019] (1) The sealing structure for a direct current steam generator for a small reactor described in the present invention solves the problem that the sealing structure of the direct current steam generator for a small reactor is prone to sealing failure and leakage. The trapezoidal inclined surface inside the groove structure contacts the inclined surface on the sealing ring, thereby decomposing the pressing force on the sealing ring into vertical force and horizontal force. When the water inlet pipe is displaced or rebounds, the sealing effect can still be ensured.

[0020] (2) The sealing structure for a direct current steam generator for a small reactor described in the present invention is further provided with a second sealing groove at the position where the head and the tube sheet flange are connected, and an octagonal gasket is provided in the second sealing groove to form an auxiliary sealing structure to enhance the sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0022] In the attached picture:

[0023] Figure 1 It is a structural schematic diagram of a sealing structure for a once-through steam generator of a small reactor according to the present invention;

[0024] Figure 2 It is a structural schematic diagram of the cooperation between a sealing ring and a groove structure of a sealing structure for a small reactor direct current steam generator according to the present invention;

[0025] Figure 3 It is a cross-sectional schematic diagram of a groove structure of a sealing structure for a small reactor once-through steam generator according to the present invention;

[0026] Figure 4 It is a cross-sectional schematic diagram of a sealing ring of a sealing structure for a small reactor once-through steam generator according to the present invention;

[0027] Figure 5 It is a partial enlarged view of a sealing structure for a small reactor once-through steam generator according to the present invention at position I and a force schematic diagram;

[0028] Among them: 1-head, 2-water inlet pipe interface, 3-steam outlet pipe, 4-tube sheet, 5-octagonal gasket, 6-groove structure, 7-sealing groove 1, 8-sealing ring, 9-sealing groove 2. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0031] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0032] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] Specific implementation method 1: See Figure 1-Figure 5 The sealing structure for a small reactor direct current steam generator described in this embodiment specifically comprises a head 1, a water inlet pipe 2 and a tube sheet 4. The head 1 is sleeved on the water inlet pipe 2 and is Figure 1 The connection is made by welding at C in the middle. A flange is provided on the head 1 and is bolted to the tube sheet 4 through the flange. The shape of the head 1 is elliptical. An annular groove structure 6 is provided at one end of the water inlet pipe 2. Figure 2 The middle D is connected by welding, a sealing groove 7 is provided on the tube sheet 4, the groove structure 6 is inserted into the sealing groove 7, and a sealing ring 8 is provided between the groove structure 6 and the sealing groove 7; the sealing groove 7 is a rectangular groove.

[0034] The cross-sectional shape of the groove inside the groove structure 6 is a right-angled trapezoid; the long bottom side of the right-angled trapezoid is the groove opening, the distance between the inner wall of the hypotenuse and the axis of the water inlet pipe 2 is smaller than the distance between the inner wall of the right-angled side and the axis of the water inlet pipe 2; the inner wall of the hypotenuse is in contact with the sealing ring 8.

[0035] The included angle between the inner wall of the hypotenuse of the groove structure 6 and the vertical direction is 28 degrees.

[0036] The inclined inner wall of the groove structure 6 and the corner of the bottom of the groove are provided with circular grooves to prevent the inclined inner wall and the sealing ring 8 from being damaged when they are in contact and squeezed during sealing. Figure 3 As shown; the material of the groove structure 6 is made of steel with high temperature resistance and excellent resilience.

[0037] The sealing ring 8 is a D-type sealing ring, and its cross-sectional shape has a right-angled trapezoid in the upper half and a semicircular cross-sectional shape in the lower half. The plane of the semicircular portion is connected to the long bottom plane of the right-angled trapezoid portion; the hypotenuse of the right-angled trapezoid of the sealing ring 8 contacts the hypotenuse inner wall inside the groove structure 6.

[0038] The angle between the hypotenuse of the right-angled trapezoidal part of the cross section of the sealing ring 8 and the vertical direction is 30 degrees.

[0039] A sealing groove 2 9 is provided on the flange of the head 1 and the tube sheet 4, and an octagonal gasket 5 is provided in the sealing groove 2 9; the sealing groove 2 9 is a trapezoidal groove; under the extrusion of the head 1 and the tube sheet 4, an auxiliary seal is formed by the sealing groove 2 9 and the octagonal gasket 5.

[0040] The end cap 1 is provided with a steam outlet pipe 3 .

[0041] The specific working principle of the sealing structure for a small reactor once-through steam generator described in the present invention is:

[0042] After the bolts are tightened, the contact surface between the groove structure 6 and the sealing ring 8 will produce a small displacement within the elastic range of the material. At this time, the angle between the sealing surface and the vertical direction is between 28° and 30°. The pressing force F of the groove structure 6 on the sealing ring can be decomposed into F in the horizontal direction. x and the vertical F y , the compression force F at point B y ′=F y , so that the sealing of point A and point B can be achieved, as shown in the attached Figure 5 shown.

[0043] At the same time, if attached Figure 5 It can be seen that due to the elastic deformation of the contact surface between the groove structure 6 and the sealing ring 8, when the water inlet pipe 2 is displaced axially upward or radially inward under a certain load, the side of the groove structure 6 in contact with the sealing ring 8 will rebound and continue to press point A on the sealing ring 8, thereby pressing point B to ensure the sealing effect; and when it is displaced axially downward or radially outward, a self-tightening sealing effect will be produced.

[0044] To summarize the above implementation cases, the sealing structure for a small reactor DC steam generator described in the present invention solves the problem that the sealing structure of the existing small reactor DC steam generator is prone to sealing failure and leakage. The trapezoidal slope inside the groove structure 6 contacts the slope on the sealing ring 8, and the pressing force on the sealing ring 8 is decomposed into vertical force and horizontal force. When the water inlet pipe 2 is displaced or rebounds, the sealing effect can still be guaranteed. The sealing structure for a small reactor DC steam generator described in the present invention is also provided with a sealing groove 2 at the position where the head and the tube sheet flange are connected, and an octagonal gasket is provided in the sealing groove 2 to form an auxiliary sealing structure to enhance the sealing effect.

[0045] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the invention. It can also be a reasonable combination of the features recorded in the above implementation methods. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A sealing structure for a small reactor once-through steam generator, characterized in that: The invention comprises a sealing head (1), a water inlet pipe (2) and a tube sheet (4); the sealing head (1) is mounted on the water inlet pipe (2) and connected to the tube sheet (4); a groove structure (6) is provided at one end of the water inlet pipe (2); a sealing groove (7) is provided on the tube sheet (4); the groove structure (6) is inserted into the sealing groove (7); and a sealing ring (8) is provided between the groove structure (6) and the sealing groove (7).

2. The sealing structure for a small reactor once-through steam generator according to claim 1, characterized in that: The cross-sectional shape of the inner groove of the groove structure (6) is a right-angled trapezoid; the long bottom side of the right-angled trapezoid is the groove opening, and the inner wall of the oblique side is in contact with the sealing ring (8).

3. The sealing structure for a small reactor once-through steam generator according to claim 2, characterized in that: The included angle between the hypotenuse inner wall of the groove structure (6) and the vertical direction is 28 degrees.

4. The sealing structure for a small reactor once-through steam generator according to claim 2 or 3, characterized in that: Circular grooves are provided on the inner wall of the oblique side of the groove structure (6) and at the corners of the bottom of the groove.

5. The sealing structure for a small reactor once-through steam generator according to claim 2, characterized in that: The upper half of the cross-sectional shape of the sealing ring (8) is a right-angled trapezoid, and the lower half is a semicircle, and the hypotenuse of the right-angled trapezoid contacts the hypotenuse inner wall of the groove structure (6).

6. The sealing structure for a small reactor once-through steam generator according to claim 5, characterized in that: The angle between the hypotenuse of the right-angled trapezoidal part of the sealing ring (8) and the vertical direction is 30 degrees.

7. The sealing structure for a small reactor once-through steam generator according to claim 1, characterized in that: The sealing head (1) and the tube sheet (4) are both provided with a second sealing groove (9), and an octagonal gasket (5) is provided in the second sealing groove (9).

8. The sealing structure for a small reactor once-through steam generator according to claim 7, characterized in that: The second sealing groove (9) is a trapezoidal groove.

9. The sealing structure for a small reactor once-through steam generator according to claim 1, characterized in that: The sealing groove 1 (7) is a rectangular groove.

10. The sealing structure for a small reactor once-through steam generator according to claim 1, characterized in that: The sealing head (1) is provided with a steam outlet pipe (3).

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