A pressureless ring guide vane journal seal structure

Abstract

The utility model discloses a kind of no-pressure ring guide vane journal sealing structure, including a pair of opposite U-shaped combination sealings, U-shaped combination sealing is installed in the shaft hole of movable guide vane bottom ring or top cover sealing seat, U-shaped combination sealing includes U-shaped seal and O-shaped seal, O-shaped seal is built-in in the U-shaped groove of U-shaped seal.The U-shaped combination sealing in the sealing structure is closed loop structure, avoid the problem that the gap of existing open loop lap joint structure is easy to produce and lead to water seepage, reduce the possibility of water seepage, improve the reliability of sealing;Form stable sealing fit form and tight form by opposite installation, ensure the reliability of sealing in long-term operation;And no need to set pressure ring, realize sealing installation and tight by the axial pressure of movable guide vane thrust disc, structure is more simple, convenient to install, reduce maintenance cost.

Description

Technical Field

[0001] This utility model relates to the field of sealing technology for water turbine components, specifically to a pressureless guide vane journal sealing structure. Background Technology

[0002] In the existing sealing structure of the moving guide vanes of the water turbine (such as...) Figure 1 As shown, it mainly consists of a movable guide vane plate 1, a transition arc 2, a nitrile rubber circle 3, and a YX-type seal 4. Conventional designs employ a combination of a YX-type seal and a low-hardness nitrile rubber circle. A typical structure is as follows: a high-hardness red YX-type seal serves as the base, and a low-hardness nitrile rubber circle is installed on top of the YX-type seal. Both are assembled together within the shaft hole of the movable guide vane bottom ring or top cover sealing seat.

[0003] However, during unit operation, the low-hardness nitrile rubber circle is prone to deformation due to extrusion deformation and natural aging of the material. This deformation will first fill the designed fit gap 5 between the guide vane body and the (top cover or bottom ring) sealing seat, directly interfering with the tightening effect of the YX type seal, preventing the YX type seal from completely filling the shaft hole, ultimately leading to seal failure and water leakage. In addition, the existing high-hardness YX type seal uses fluororubber, which has poor cold resistance. In long-term immersion operation, the seal reliability is greatly reduced, making it difficult to stably guarantee the sealing effect. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides a pressureless guide vane journal sealing structure.

[0005] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: a pressure ring-free guide vane journal sealing structure, including a pair of U-shaped combined seals stacked in opposite directions, wherein the U-shaped combined seals are installed in the shaft hole of the bottom ring of the movable guide vane or the top cover sealing seat; The U-shaped combination seal includes a U-shaped seal and an O-shaped seal, with the O-shaped seal embedded in the U-shaped groove of the U-shaped seal.

[0006] Furthermore, both the U-shaped seal and the O-shaped seal are closed-loop structures.

[0007] Furthermore, the total height of a pair of opposing stacked U-shaped combination seals is greater than the depth of the sealing groove inside the shaft hole of the movable guide vane bottom ring or top cover sealing seat.

[0008] Furthermore, a pair of opposing stacked U-shaped combination seals form a two-layer stacked structure, with the U-shaped seals in the two layers of U-shaped combination seals in contact with each other, and the O-shaped seals in the two layers of U-shaped combination seals in contact with each other.

[0009] Furthermore, the U-shaped combined seal is installed and fixed by the axial pressure of the movable guide vane thrust disc.

[0010] Furthermore, the U-shaped groove of the U-shaped seal is matched with the outer dimensions of the O-shaped seal, so that the O-shaped seal is tightly fitted into the U-shaped groove.

[0011] Furthermore, the outer peripheral surface of the U-shaped combined seal fits against the inner wall of the bottom ring of the movable guide vane or the shaft hole of the top cover sealing seat, and the inner peripheral surface of the U-shaped combined seal mates with the outer peripheral surface of the movable guide vane shaft.

[0012] Furthermore, the closed-loop shape of the U-shaped seal matches the closed-loop shape of the O-shaped seal.

[0013] This utility model has the following advantages: The pressure ring-free guide vane journal sealing structure provided by this utility model has a U-shaped combined seal that is a closed-loop structure, which avoids the problem of water leakage caused by gaps in the existing open-loop overlapping structure, reduces the possibility of water leakage, and improves the reliability of the seal; the opposing installation forms a stable sealing fit and tensioning form, ensuring the reliability of the seal during long-term operation; and there is no need to set a pressure ring. The sealing installation and tensioning are achieved by the axial pressure of the movable guide vane thrust disc, which makes the structure simpler, easier to install, and reduces maintenance costs. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of an existing sealing structure; Figure 2 This is a schematic diagram of the sealing structure in this utility model; Figure 3 This is a cross-sectional view of the sealing structure installation in this utility model; Figures 1 to 3 The reference numerals in the attached figures are respectively: 1-movable guide vane plate, 2-transition arc, 3-nitrile rubber circle, 4-YX type seal, 5-fitting clearance, 6-movable guide vane shaft, 7-U-type seal, 8-bottom ring or top cover sealing seat, 9-O-type seal, 10-U-type combination seal. Detailed Implementation

[0015] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0016] like Figures 2 to 3As shown, a pressure-free guide vane journal sealing structure includes a pair of opposing stacked U-shaped combined seals 10. The U-shaped combined seals 10 are installed in the shaft hole of the movable guide vane bottom ring or top cover sealing seat 8. The U-shaped combined seals 10 include a U-shaped seal 7 and an O-shaped seal 9, with the O-shaped seal 9 embedded in the U-shaped groove of the U-shaped seal 7. Both the U-shaped seal 7 and the O-shaped seal 9 are closed-loop structures, and the total height of the pair of opposing stacked U-shaped combined seals 10 is greater than the depth of the sealing groove in the shaft hole of the movable guide vane bottom ring or top cover sealing seat 8. Pre-compression is achieved in the initial installation state, reserving basic pressure for subsequent sealing deformation. Preferably, the U-shaped seal is made of high-hardness red polyurethane material that is oil-resistant, wear-resistant, cold-resistant, and has strong adhesion, while the O-shaped seal is made of medium-hardness, high-elasticity NBR material that is oil-resistant, wear-resistant, cold-resistant, and has strong adhesion. Long-term contact and compression between the U-shaped seal and the O-shaped seal will not result in mutual dissolution.

[0017] The U-shaped combination seal 10 serves as the core sealing unit. Through the nested fit of the U-shaped seal 7 and the O-shaped seal 9, a double-sealing structure is formed, jointly undertaking the function of preventing water leakage. The U-shaped groove of the U-shaped seal 7 provides installation space and positioning for the O-shaped seal 9, ensuring its stable embedding and preventing it from easily falling off. Simultaneously, the structural strength of the U-shaped seal 7 limits excessive deformation of the O-shaped seal 9, ensuring the stability of the seal. The O-shaped seal 9 uses its own elasticity to fill the gap within the U-shaped groove and deforms under pressure, assisting the U-shaped seal 7 in conforming to the inner wall of the shaft hole, enhancing the tightness of the seal.

[0018] A pair of opposing U-shaped combined seals 10 form a two-layer stacked structure. The U-shaped seals 7 in the two layers of U-shaped combined seals 10 are in contact with each other, and the O-shaped seals 9 in the two layers of U-shaped combined seals are in contact with each other. Under pressure, the two opposing U-shaped combined seals 10 form sealing surfaces on both sides. Combined with the nested fit of the U-shaped and O-shaped seals 9, they jointly block the water flow channel, achieving a reliable seal at the journal and effectively preventing water leakage. Furthermore, the opposing U-shaped combined seals 10 form a "two-way barrier" with two sealing structures. Even if one layer has a small gap due to local wear or deformation, the other layer can still perform a sealing function, greatly reducing the risk of water leakage. The opposing stacking design makes the two layers of seals experience forces in opposite directions. Under axial pressure, they can respectively adhere to the inner walls of the shaft hole on both sides, expanding the sealing coverage and ensuring a complete seal in the circumferential direction of the shaft hole.

[0019] The U-shaped combined seal 10 is installed and fixed by the axial pressure of the movable guide vane thrust disc. The shaft hole of the movable guide vane bottom ring / top cover sealing seat 8 provides the U-shaped combined seal 10 with an installation carrier and positioning space. The radial displacement of the seal is constrained by the inner wall of the shaft hole, ensuring the fitting accuracy between the seal and the shaft hole. The movable guide vane thrust disc provides axial pressure, squeezing the opposing stacked U-shaped combined seals 10, causing the seal to deform to fill the shaft hole gap, achieving a "self-tightening seal" and enhancing the fit between the seal and the shaft hole and the movable guide vane shaft 6.

[0020] During installation, the O-ring seal 9 is first embedded into the U-groove of the U-ring seal 7 to form a U-shaped combined seal 10. Then, a pair of U-shaped combined seals 10 are stacked opposite each other and placed into the shaft hole of the bottom ring or top cover sealing seat 8 of the movable guide vane. At this time, the total height of the two layers of U-shaped combined seals 10 is greater than the depth of the sealing groove, forming a pre-compressed state. When the movable guide vane is running, the thrust disc generates axial pressure, squeezing the stacked U-shaped combined seals 10. Under pressure, the U-shaped seal 7 expands to both sides due to its structural rigidity, and its outer circumferential surface tightly adheres to the inner wall of the shaft hole. Simultaneously, the O-ring seal 9, due to elastic deformation, fills the tiny gaps in the U-groove and assists the U-shaped seal 7 in adhering to the outer circumferential surface of the movable guide vane shaft 6.

[0021] A pair of opposing U-shaped combined seals 10 form a two-layer stacked structure. The U-shaped seals 7 in the two layers of U-shaped combined seals 10 are in contact with each other, and the O-shaped seals 9 in the two layers of U-shaped combined seals are in contact with each other. The U-shaped groove size of the U-shaped seal 7 matches the outer dimensions of the O-shaped seal 9, allowing the O-shaped seal 9 to be tightly fitted within the U-shaped groove. The outer circumferential surface of the U-shaped combined seal 10 fits against the inner wall of the shaft hole of the movable guide vane bottom ring or top cover sealing seat 8, and the inner circumferential surface of the U-shaped combined seal 10 mates with the outer circumferential surface of the movable guide vane shaft 6. The O-shaped seal 9 is tightly fitted within the U-shaped groove because its U-shaped groove size matches its own outer dimensions, forming an integral sealing unit. A pair of these units are stacked opposite each other as a two-layer structure, with the U-shaped seals 7 and O-shaped seals 9 in contact with each other, ensuring no gaps after stacking. During installation, the outer circumferential surface of the U-shaped combined seal 10 fits against the inner wall of the shaft hole of the bottom ring of the movable guide vane or the top cover sealing seat 8, and the inner circumferential surface initially matches the outer circumferential surface of the movable guide vane shaft 6, laying the foundation for sealing. When the movable guide vane is running, the thrust disc generates axial pressure acting on the two opposing stacked U-shaped combined seals 10. The pressure causes the two U-shaped seals 7 to squeeze against each other, expanding radially due to the characteristics of the U-shaped structure. Their outer circumferential surfaces fit even more tightly against the inner wall of the shaft hole, while their inner circumferential surfaces fit even more tightly against the outer circumferential surface of the movable guide vane shaft 6. At the same time, the O-ring seals 9 in contact with each other deform elastically, filling the tiny gaps in the U-shaped groove and assisting the U-shaped seals 7 in enhancing the radial contact force, forming a "bidirectional sealing surface" that improves the sealing effect.

[0022] Additionally, it should be noted that components not described in detail in this article are existing technologies.

[0023] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A pressureless guide vane journal sealing structure, characterized in that, It includes a pair of U-shaped combined seals (10) stacked in opposite directions, the U-shaped combined seals (10) being installed in the shaft hole of the movable guide vane bottom ring or top cover sealing seat (8); The U-shaped combined seal (10) includes a U-shaped seal (7) and an O-shaped seal (9), wherein the O-shaped seal (9) is built into the U-shaped groove of the U-shaped seal (7).

2. The pressureless ring guide vane journal sealing structure according to claim 1, characterized in that, Both the U-shaped seal (7) and the O-shaped seal (9) are closed-loop structures.

3. The pressureless ring guide vane journal sealing structure according to claim 1, characterized in that, The total height of a pair of opposing stacked U-shaped combination seals (10) is greater than the depth of the sealing groove in the shaft hole of the movable guide vane bottom ring or top cover sealing seat (8).

4. The pressureless ring guide vane journal sealing structure according to claim 1, characterized in that, The pair of opposing stacked U-shaped combination seals (10) form a two-layer stacked structure. The U-shaped seals (7) in the two U-shaped combination seals (10) are in contact with each other, and the O-shaped seals (9) in the two U-shaped combination seals are in contact with each other.

5. The pressureless ring guide vane journal sealing structure according to claim 1, characterized in that, The U-shaped combined seal (10) is installed and fixed by the axial pressure of the movable guide vane thrust disc.

6. The pressureless ring guide vane journal sealing structure according to claim 1, characterized in that, The U-shaped groove of the U-shaped seal (7) is adapted to the outer dimensions of the O-shaped seal (9), so that the O-shaped seal (9) is tightly fitted into the U-shaped groove.

7. The pressureless ring guide vane journal sealing structure according to claim 6, characterized in that, The outer circumferential surface of the U-shaped combined seal (10) is in contact with the inner wall of the shaft hole of the movable guide vane bottom ring or top cover sealing seat (8).

8. The pressureless ring guide vane journal sealing structure according to claim 6, characterized in that, The inner circumferential surface of the U-shaped combined seal (10) mates with the outer circumferential surface of the movable guide vane shaft (6).

9. The pressureless ring guide vane journal sealing structure according to claim 1, characterized in that, The closed-loop shape of the U-shaped seal matches the closed-loop shape of the O-shaped seal.

10. The pressureless guide vane journal sealing structure according to claim 1, characterized in that, The U-shaped seal (7) is made of high-hardness polyurethane material.

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