A packing seal device for a seawater circulating pump

Abstract

The application belongs to the technical field of nuclear power plant rotating equipment maintenance, and particularly relates to a seawater circulating pump packing seal device. The device comprises a protection shaft sleeve, a packing gland and a labyrinth seal ring. The protection shaft sleeve is sleeved on a pump shaft and fastened in place. The packing gland is sleeved outside the protection shaft sleeve, and the labyrinth seal ring is installed in the packing gland. A radial gap is arranged between the labyrinth seal ring and the protection shaft sleeve. A sealing device composed of a sealing compression ring and a sealing ring is installed on the upper portion of the protection shaft sleeve, which can effectively prevent seawater corrosion and silt deposition, and avoid the problem of difficult disassembly of the protection shaft sleeve.

Description

Technical Field

[0001] This application belongs to the field of nuclear power plant rotating equipment maintenance technology, specifically relating to a seawater circulating pump packing seal device. Background Technology

[0002] A nuclear power plant unit is equipped with 10 seawater circulating pumps to supply circulating cooling water to the turbine condenser and discharge the circulating water from the condenser into the sea. The pump is a vertical mixed-flow pump, transporting seawater, and uses a packing seal for its shaft. Due to a relatively large radial clearance (2.5mm on each side) between the bottom of the stuffing box and the protective shaft sleeve in the pump's design, the packing deforms and embeds itself in the gap under the pressure of the gland, thus blocking the passage for the shaft seal cooling water to flow into the pump chamber. This causes repeated instances of reduced shaft seal cooling water flow during pump operation, affecting the lubrication and cooling of the shaft seal and reducing pump reliability. This pump is a single-point sensitive piece of equipment in the nuclear power plant; decreased reliability will affect the safe and stable operation of the unit. Furthermore, the pump shaft is made of carbon steel, and the section above the rubber seal ring of the protective shaft sleeve that mates with the pump shaft is susceptible to corrosion from leaking water. Sediment accumulates in the gap between the protective shaft sleeve and the pump shaft, making disassembly of the protective shaft sleeve difficult. Destructive disassembly would render the protective shaft sleeve unusable and also increases the risk of pump shaft damage. Summary of the Invention

[0003] The purpose of this application is to provide a packing seal device for a seawater circulating pump to solve the problem of low shaft seal water flow.

[0004] The technical solution to achieve the purpose of this application is as follows:

[0005] This application provides a seawater circulating pump packing seal device, the device comprising: a protective shaft sleeve, a stuffing box, and a labyrinth sealing ring;

[0006] The protective bushing is fitted onto the pump shaft and tightened in place;

[0007] The stuffing box is fitted outside the protective bushing, and a labyrinth seal ring is installed inside the stuffing box; a radial clearance is provided between the labyrinth seal ring and the protective bushing.

[0008] Optionally, the radial clearance between the labyrinth seal ring and the protective bushing is 1 mm.

[0009] Optionally, the stuffing box and the labyrinth seal ring are secured by countersunk screws B.

[0010] Optionally, a water seal ring and packing are installed on the upper part of the labyrinth sealing ring; a packing gland is installed on the upper end of the packing; the packing gland is fixed to the stuffing box by double-ended bolts.

[0011] Optionally, the upper part of the labyrinth sealing ring is equipped with a packing ring, a water seal ring and three packing rings, and the top packing ring is fitted with a packing gland.

[0012] Optionally, a rubber sealing ring B may be installed in the lower annular groove of the stuffing box.

[0013] Optionally, a rubber sealing ring A and a sealing pressure ring are installed on the upper end face of the protective bushing, and a countersunk screw A is installed between the sealing pressure ring and the protective bushing for fixation.

[0014] Optionally, a flat washer and nut can be installed on the double-ended bolt. The nut can be manually tightened but not fully tightened. After the pump is started, the nut can be adjusted by symmetrically tightening it with a wrench according to the amount of shaft seal leakage.

[0015] The beneficial technical effects of this application are as follows:

[0016] 1) The seawater circulating pump shaft seal device provided in this application embodiment has a simple structure and is easy to disassemble and assemble; the labyrinth sealing ring can effectively solve the problem of low shaft seal water flow; the sealing device consisting of a sealing pressure ring and a sealing ring installed on the upper part of the protective shaft sleeve can effectively prevent seawater corrosion and sediment deposition, and avoid the problem of difficult disassembly of the protective shaft sleeve; it improves the operational reliability of the seawater circulating pump and avoids the risk of shaft sleeve scrapping and pump shaft damage.

[0017] 2) The seawater circulating pump shaft sealing device provided in this application eliminates the rubber sealing ring inside the protective shaft sleeve, preventing the jamming problem caused by the rubber sealing ring when the protective shaft sleeve is disassembled, and avoiding the problem of difficulty in disassembling the protective shaft sleeve. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a seawater circulating pump shaft seal device provided in an embodiment of this application;

[0019] Figures 2a-2c This is a schematic diagram of the structure of a labyrinth sealing ring in a shaft sealing device for a seawater circulating pump, provided in an embodiment of this application.

[0020] Figure 3 This is a schematic diagram of the sealing ring in a seawater circulating pump shaft sealing device provided in an embodiment of this application.

[0021] In the picture:

[0022] 1. Pump shaft, 2. Double-ended bolt, 3. Nut, 4. Flat washer, 5. Packing gland, 6. Sealing ring, 7. Rubber sealing ring A, 8. Countersunk screw A, 9. Protective shaft sleeve, 10. Stuffing box, 11. Packing, 12. Water seal ring, 13. Countersunk screw B, 14. Labyrinth seal ring, 15. Rubber sealing ring B. Detailed Implementation

[0023] To enable those skilled in the art to better understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only a part of the embodiments of this application, and not all of them. Based on the embodiments described in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] In the description of the embodiments of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0025] See Figure 1 The figure is a schematic diagram of the structure of a seawater circulating pump packing seal device provided in an embodiment of this application.

[0026] This application provides a seawater circulating pump packing seal device, including: a protective shaft sleeve 9, a stuffing box 10, and a labyrinth sealing ring 14;

[0027] The protective bushing 9 is fitted onto the pump shaft 1 and tightened in place;

[0028] The stuffing box 10 is fitted on the outside of the protective bushing 9, and a labyrinth seal ring 14 is installed inside the stuffing box 10. A radial gap is provided between the labyrinth seal ring 14 and the protective bushing 9 to prevent the packing from being squeezed and blocking the downward passage of the shaft seal cooling water. The labyrinth structure of the labyrinth seal ring 14 can also control the excessive downward flow of the shaft seal cooling water, thereby ensuring a stable flow of the shaft seal cooling water and ensuring good lubrication of the packing 11 and the protective bushing 9 inside the stuffing box 10. Figures 2a-2c An example is shown of the structure of a labyrinth sealing ring.

[0029] In one example, the radial clearance between the labyrinth seal ring 14 and the protective bushing 9 is 1 mm.

[0030] In practice, the stuffing box 10 and the labyrinth sealing ring 14 are fixed together by countersunk screws B13.

[0031] In some possible implementations of this application, a water seal ring 12 and a packing 11 are installed on the upper part of the labyrinth sealing ring 14; a packing gland 5 is installed on the upper end of the packing 11; the packing gland 5 is fixed to the stuffing box 10 by double-headed bolts 2.

[0032] In practice, a flat washer and nut 3 are installed on the double-ended bolt 2. Nut 3 is manually put on but not tightened. After the pump is started, the nut 3 is tightened symmetrically with a wrench according to the leakage of the shaft seal.

[0033] In one example, the upper part of the labyrinth sealing ring 14 is successively equipped with a packing 11, a water seal ring 12 and three packings 11, and the top packing 11 is equipped with a packing gland 5.

[0034] In one example, a rubber sealing ring B15 is installed in the lower annular groove of the stuffing box 10.

[0035] In some possible implementations of this application, a rubber sealing ring A7 and a sealing pressure ring 6 are installed on the upper end face of the protective bushing 9. A countersunk screw A8 is installed between the sealing pressure ring 6 and the protective bushing 9 for fixation. The rubber sealing ring A7 prevents seawater from entering the gap between the protective bushing and the pump shaft 1, thus avoiding seawater corrosion of the pump shaft 1 and preventing sediment from accumulating in the gap between the two. Figure 3 An example of a sealing ring structure is shown.

[0036] The following detailed explanation, using a specific example, illustrates the installation method of a seawater circulating pump shaft seal device provided in this application. Specifically:

[0037] 【1】Clean the mating surfaces of the pump shaft 1 and the protective bushing 9 by grinding;

[0038] [2] Heat the protective bushing 9 to about 80°C, put the protective bushing 9 onto the pump shaft 1 and tighten it in place;

[0039] 【3】After the protective bushing 9 has cooled down, clean the upper surface of the protective bushing 9, apply silicone grease to the rubber sealing ring A 7, and put it on the pump shaft 1 until it contacts the upper surface of the protective bushing 9. Install the sealing pressure ring 6, align the bolt holes, and install the countersunk screws A8 to tighten them symmetrically in place.

[0040] [4] Install rubber sealing ring B15 in the lower annular groove of stuffing box 10, install stuffing box 10 in place and tighten it with bolts;

[0041] 【5】Install the labyrinth seal ring 14 inside the stuffing box 10, check the radial clearance between the labyrinth seal ring 14 and the protective bushing 9 with a feeler gauge, ensure that the labyrinth seal ring is skewed, align it and install and tighten the countersunk screw B13.

[0042] [6] Install a packing material 11 on the upper part of the labyrinth sealing ring;

[0043] 【7】Install water seal ring 12 and install 3 packing layers 11;

[0044] 【8】Install double-ended bolts 2 in the corresponding bolt holes of stuffing box 10;

[0045] [9] Install the packing gland 5;

[0046]

[10] Install flat washers and nuts 3 on the double-ended bolts. Manually put on nuts 3 but do not tighten them. After the pump starts, adjust the nuts 3 by symmetrically tightening them with a wrench according to the amount of shaft seal leakage.

[0047] In the seawater circulating pump shaft seal device provided in this application embodiment, the rubber sealing ring A7 can effectively prevent seawater from entering the gap between the protective sleeve 9 and the pump shaft 1, avoiding seawater corrosion of the pump shaft and preventing sediment from accumulating in the gap between them. The radial gap between the labyrinth sealing ring 14 fixed in the stuffing box 10 and the protective sleeve 9 is reduced to 1mm, preventing the packing from being squeezed and blocking the downward channel of the shaft seal cooling water. The labyrinth structure can also control the downward flow of the shaft seal cooling water to prevent it from being too large, thereby ensuring a stable flow of the shaft seal cooling water and ensuring good lubrication of the packing 11 and the protective sleeve 9.

[0048] The present application has been described in detail above with reference to the accompanying drawings and embodiments. However, the present application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present application. All content not described in detail in this application can be derived from existing technology.

Claims

1. A stuffing box assembly for a sea water circulating pump, characterized by The device comprises a protection sleeve (9), a stuffing box (10) and a labyrinth seal ring (14); The protection sleeve (9) is sleeved on the pump shaft (1) and fastened in place; The stuffing box (10) is sleeved outside the protection sleeve (9), and the labyrinth seal ring (14) is installed in the stuffing box (10); a radial gap is arranged between the labyrinth seal ring (14) and the protection sleeve (9); The radial gap between the labyrinth seal ring (14) and the protection sleeve (9) is 1mm; The stuffing box (10) and the labyrinth seal ring (14) are fixed by means of the countersunk screw B (13); A water seal ring (12) and a packing (11) are installed on the upper portion of the labyrinth seal ring (14); the upper end of the packing (11) is installed with a packing gland (5); the packing gland (5) is fixed with the stuffing box (10) through the stud bolt (2); A flat washer and a nut (3) are installed on the stud bolt (2); the nut (3) is manually put on but not tightened; after the pump is started, the nut (3) is symmetrically tightened and adjusted according to the shaft seal leakage; A packing (11), a water seal ring (12) and three packings (11) are installed on the upper portion of the labyrinth seal ring (14) one by one; the upper end of the topmost packing (11) is installed with the packing gland (5); A rubber sealing ring B (15) is installed in the lower annular groove of the stuffing box (10); A rubber sealing ring A (7) and a sealing compression ring (6) are installed on the upper end face of the protection sleeve (9); the sealing compression ring (6) and the protection sleeve (9) are fixed by means of the countersunk screw A (8).

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