Main shaft seal of bulb tubular turbine

Abstract

The invention relates to the technical field of water turbine sealing, in particular to a bulb tubular water turbine main shaft seal which comprises a water turbine assembly, the water turbine assembly comprises a water turbine main shaft and a sealing bush installed on the outer side of the water turbine main shaft, and the sealing bush is used for providing preliminary sealing between the water turbine main shaft and a fixing component; the soft cushion box surrounds the exterior of the sealing bush, and the soft cushion box is fixed to a fixing component of the water turbine in a bolt or buckle mode; and the C-shaped shroud ring is wound and mounted between the sealing bush and the soft cushion box layer by layer in a spiral staggered manner. The bulb tubular turbine set has the beneficial effects that the C-shaped shroud rings are installed in a spiral staggered mode, leakage of water flow in a gap formed between the rotating component and the static component can be effectively reduced, and through the structural design, the problem that water leaks at the position of the main shaft in the running process of the bulb tubular turbine set can be effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of water turbine sealing, in particular to a main shaft seal of a bulb tubular water turbine. Background Art

[0002] For turbines, the runner anti-leakage ring will produce a small amount of water leakage, which will enter the machine pit along the gap between the main shaft and the fixed parts, hindering the normal operation of other equipment. Therefore, a anti-leakage sealing device (referred to as the main shaft seal) must be installed on the main shaft. Whether it is a vertical unit or a horizontal unit, the turbine has a main shaft seal structure. For the most popular and commonly used Francis turbine, the main shaft seal structure is fixed and the technology is relatively mature. However, the bulb-type tubular turbine used in most riverbed hydropower stations adopts a horizontal layout. The unit structure is different from the vertical layout of the Francis turbine, so the structure and requirements of the main shaft seal are also different.

[0003] Some turbine main shaft seals use a labyrinth seal structure. The labyrinth seal is a sealing structure formed by the rapid loss of energy when the liquid forms a labyrinth channel between the rotating shaft and the sealing cover. The narrower the labyrinth gap and the more complex the channel, the better the labyrinth seal effect. However, in general, the machinery using this seal will have the shaft expand or move due to the increase in temperature inside the machine during operation, which requires the labyrinth seal to have enough clearance to prevent mutual contact. Labyrinth seals are mostly used for steam seals or other occasions where a certain amount of leakage is allowed. The sealing surface of the labyrinth seal is always in a full medium lubrication state, with no friction, low power consumption, no loss during normal operation, long life, simple maintenance, good sealing performance, and the higher the speed, the better the sealing effect, but the sealing parts require high processing accuracy, difficult assembly, and large leakage.

[0004] The labyrinth seal is widely used in Francis turbines and has good effect. However, when used in bulb-type turbines, the seal ring is lowered due to gravity, resulting in uneven upper and lower seal gaps and water leakage. The bulb-type turbine has a low speed but a large flow rate. Once the main shaft seal leaks, the water leakage will be very large, which will have a great impact on the safe operation of the unit. Summary of the invention

[0005] Some simplifications or omissions may be made in this section and the abstract and title of the present application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions shall not be used to limit the scope of the present invention.

[0006] The object of the present invention is to provide a main shaft seal for a bulb tubular turbine.

[0007] Therefore, the purpose is to solve the problem that on a bulb tubular turbine, the sealing ring is lowered due to gravity, resulting in uneven upper and lower sealing gaps and water leakage.

[0008] To solve the above technical problems, the present invention provides the following technical solutions: a bulb-type cross-flow turbine main shaft seal, which includes a turbine assembly, which includes a turbine main shaft and a sealing bushing installed on the outside of the turbine main shaft, the sealing bushing is used to provide a preliminary seal between the turbine main shaft and a fixed component; a cushion box surrounding the outside of the sealing bushing, wherein the cushion box is fixed to the fixed component of the turbine by bolts or snaps; a C-shaped belt, the C-shaped belt is installed between the sealing bushing and the cushion box by spirally winding layer by layer, and a certain overlapping area is formed between two adjacent layers of the C-shaped belt.

[0009] As a preferred solution for the main shaft seal of the bulb-type tubular turbine of the present invention, the C-shaped belt is installed in a multi-layer staggered winding manner, wherein each layer is fixed to each other by a special adhesive or mechanical fixing parts.

[0010] As a preferred solution for the main shaft seal of the bulb-type tubular turbine of the present invention, the installation angle of the C-shaped shroud ensures that the contact surface between the C-shaped shroud and the sealing bushing is perpendicular to the water flow direction.

[0011] As a preferred solution for the main shaft seal of the bulb tubular turbine of the present invention, the material of the C-shaped shroud is selected from any one or more combinations of polyurethane, rubber or synthetic fiber materials.

[0012] As a preferred solution for the main shaft seal of the bulb-type tubular turbine of the present invention, a pressure pad water tank is provided on one side of the C-shaped shroud, and the interior of the pressure pad water tank is a cavity structure.

[0013] As a preferred solution for the main shaft seal of the bulb-type cross-flow turbine of the present invention, the outer ring of the pressure pad water tank is provided with at least one drain pipe, the drain pipe is fixed to the pressure pad water tank by welding or threaded connection, and the outer side of the drain pipe is provided with a waterproof sealing ring.

[0014] As a preferred solution for the main shaft seal of the bulb-type cross-flow turbine of the present invention, the pressure pad water tank is connected to the cavity formed between the sealing bushing and the cushion box, and the water flowing out of the gap of the C-shaped belt can enter the pressure pad water tank through the cavity.

[0015] As a preferred solution for the main shaft seal of the bulb-type cross-flow turbine of the present invention, the pressure pad water tank also includes a pressure sensor for monitoring the changes in water pressure inside the pressure pad water tank and issuing an alarm signal when the preset threshold is exceeded, and the pressure sensor is connected to the control system via a cable or wirelessly.

[0016] As a preferred solution for the main shaft seal of the bulb-type cross-flow turbine of the present invention, the drain pipe is provided with a valve device which can be closed during the shutdown and maintenance of the unit to prevent external impurities from entering the pressure pad water tank.

[0017] As a preferred solution for the main shaft seal of the bulb-type cross-flow turbine of the present invention, the drain pipe is connected to the drain pipeline of the turbine assembly, so that the water discharged from the pressure pad water tank flows into the main drain channel.

[0018] The beneficial effect of the main shaft seal of the bulb-type cross-flow turbine of the present invention is that by using C-shaped belts for installation in a spirally staggered manner, the leakage of water in the gap formed between the rotating parts and the stationary parts can be effectively reduced. Through the design of the above structure, the problem of water leakage at the main shaft during the operation of the bulb-type cross-flow turbine unit can be effectively solved.

[0019] The sealing effect is enhanced by overlapping the layers of the C-shaped belt. This design not only ensures sufficient sealing strength, but also avoids material aging and failure caused by excessive compression.

[0020] The combined use of C-shaped belt and sealing bushing not only enhances the sealing performance, but also effectively absorbs the vibration and wear generated during the operation of the machine.

[0021] After long-term operation, the C-shaped belt will leak in a small area due to wear. The pressure pad water tank and its drainage pipeline can also discharge this part of the water flow in time to avoid damage to the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0023] Figure 1 The figure is a schematic diagram of the overall cross-sectional structure of the main shaft seal of the bulb tubular turbine in the present invention.

[0024] Figure 2 The main shaft seal of the bulb tubular turbine of the present invention Figure 1 Schematic diagram of the enlarged structure of part A in the middle.

[0025] In the figure:

[0026] 100. turbine assembly; 101. turbine main shaft; 102. sealing bushing; 103. fixing part;

[0027] 200, padded box;

[0028] 300, C-shaped belt;

[0029] 400. Pressure pad water tank; 401. Drain pipe. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0031] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0032] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0033] Example 1

[0034] Reference Figure 1-2 , which is the first embodiment of the present invention, and provides a bulb-type cross-flow turbine main shaft seal, including a turbine assembly 100, which includes a turbine main shaft 101 and a sealing bushing 102 installed on the outside of the turbine main shaft 101, the sealing bushing 102 is used to provide a preliminary seal between the turbine main shaft 101 and a fixed component 103; a cushion box 200, which surrounds the outside of the sealing bushing 102, wherein the cushion box 200 is fixed to the fixed component 103 of the turbine by bolts or snaps; a C-shaped belt 300, which is installed between the sealing bushing 102 and the cushion box 200 layer by layer in a spiral staggered manner, and a certain overlapping area is formed between two adjacent layers of the C-shaped belt 300 to enhance the sealing effect and prevent water from flowing out through the gap between the rotating component and the stationary component.

[0035] In this embodiment, by using the C-shaped belt 300 for installation in a spiral staggered manner, it is possible to effectively reduce the leakage of water in the gap formed between the rotating parts and the stationary parts. This not only directly improves the energy conversion efficiency of the turbine, but also indirectly reduces the waste of resources caused by water leakage, thereby improving the operating efficiency of the entire hydropower station.

[0036] Among them, in a water turbine, "rotating parts" usually refer to those parts that rotate with the water flow, such as the turbine's runner or rotor, main shaft, etc. These parts rotate under the action of water force, converting the kinetic energy of water into mechanical energy.

[0037] "Stationary parts" refer to those parts that are fixed and do not move. They are usually used to support, guide water flow, or provide mechanical connections. For example, in a bulb-type hydro turbine, the stationary parts may include guide vanes, water inlet pipes, water outlet pipes, volutes, and other structures, as well as parts fixed to the turbine base or other fixed frames.

[0038] In addition, the combination of the C-shaped belt 300 and the sealing bushing 102 not only enhances the sealing performance, but also effectively absorbs the vibration and wear generated during the operation of the machine, which can significantly reduce the damage rate of the main shaft and surrounding parts, extend the overall service life of the equipment, and reduce maintenance costs.

[0039] The cushion box 200 is fixed by bolts or snaps, which makes the installation process simpler and faster, and is also convenient for later inspection and replacement of sealing materials, which can greatly reduce downtime caused by maintenance and improve the availability and maintainability of the equipment.

[0040] The innovation of the sealing device lies in its structural optimization, that is, utilizing the overlapping of the layers of the C-shaped belt 300 to enhance the sealing effect. This design not only ensures sufficient sealing strength, but also avoids material aging and failure caused by excessive compression, thus achieving an ideal state of reasonable structure and excellent performance.

[0041] In summary, the main shaft seal design of the bulb-type tubular turbine not only solves the difficulties in practical applications from a technical perspective, but also demonstrates its excellent value from multiple dimensions such as economy and environmental protection.

[0042] Example 2

[0043] Reference Figure 1-2 , which is the second embodiment of the present invention. Different from the previous embodiment, the C-shaped belt 300 is installed in a multi-layer staggered winding manner, wherein each layer is fixed to each other by a special adhesive or mechanical fastener to increase the reliability and durability of the seal. The installation angle of the C-shaped belt 300 ensures that the contact surface between it and the sealing bushing 102 is perpendicular to the water flow direction to minimize the possibility of water flowing through the gap. The material of the C-shaped belt 300 is selected from but not limited to any one or more combinations of polyurethane, rubber or synthetic fiber materials, preferably a material with water resistance and anti-aging properties.

[0044] In this embodiment, the C-shaped belt 300 is installed in a multi-layer staggered winding manner, and each layer is fixed to each other using a special adhesive or mechanical fastener, which can significantly improve the sealing of the entire device. The staggered winding makes the edge of each layer staggered with the previous layer, so that even if a certain layer is slightly displaced, it will be restricted by the position of the adjacent layer, thereby reducing the risk of sealing failure caused by single-layer displacement. At the same time, the use of special adhesives or mechanical fasteners ensures the close connection between the layers, further enhancing the stability of the overall structure.

[0045] Selecting polyurethane, rubber or synthetic fiber materials as the raw materials of the belt, and giving priority to materials with water resistance and anti-aging properties, can effectively extend the service life of the belt. These materials can not only maintain their physical properties for a long time, but also resist the influence of moisture in the environment, reducing the performance degradation caused by material aging. For equipment that is in harsh environments for a long time, the aging of materials often leads to sealing failure, which in turn affects the safe operation of the entire equipment.

[0046] Since the C-shaped belt 300 is wound in multiple layers, if a problem is found in a certain area during use, only the C-shaped belt 300 in that area needs to be replaced, which is convenient for maintenance. At the same time, since the material itself is durable, the need for frequent replacement of the C-shaped belt 300 is reduced, making maintenance work more convenient.

[0047] Secondly, the installation angle of the C-shaped belt 300 is adjusted so that the contact surface between the C-shaped belt 300 and the sealing bushing 102 is perpendicular to the water flow direction, in order to minimize the possibility of water flowing through the gap. For application scenarios involving high-pressure water flow, such a design can effectively prevent safety accidents caused by water leakage. For example, in hydropower stations, large cooling towers or industrial piping systems, it is crucial to maintain sealing performance, because any slight leakage may cause a chain reaction, leading to more serious consequences.

[0048] In summary, the C-shaped belt 300 and its installation method not only improve the traditional sealing method on the technical level, but also show significant advantages in many aspects such as economy and environmental protection.

[0049] Example 3

[0050] Reference Figure 1-2, which is the third embodiment of the present invention, and this embodiment further provides a main shaft seal for a bulb-type cross-flow turbine. A pressure pad water tank 400 is provided on one side of a C-shaped shroud 300, and the interior of the pressure pad water tank 400 is a cavity structure. At least one drain pipe 401 is provided on the outer ring of the pressure pad water tank 400, and the drain pipe 401 is fixed to the pressure pad water tank 400 by welding or threaded connection. A waterproof sealing ring is provided on the outer side of the drain pipe 401 to guide the water flow to the drain pipe 401 and discharge it naturally through the drain pipe 401 to prevent leakage when the C-shaped shroud 300 is worn or damaged and part of the water flow overflows. The pressure pad water tank 400 is connected to the cavity formed between the sealing bushing 102 and the cushion box 200, and the water flowing out of the gap of the C-shaped shroud 300 can enter the pressure pad water tank 400 through the cavity.

[0051] The pressure pad water tank 400 also includes a pressure sensor for monitoring the water pressure change inside the pressure pad water tank 400 and sending an alarm signal when it exceeds a preset threshold. The pressure sensor is connected to the control system via a cable or wirelessly. The drain pipe 401 is provided with a valve device, which includes a manual or automatic control component and can be closed during the shutdown and maintenance of the unit to prevent external impurities from entering the pressure pad water tank 400. The drain pipe 401 is connected to the drain pipe 401 of the turbine assembly 100, so that the water discharged from the pressure pad water tank 400 can be smoothly merged into the main drainage channel and discharged to a safe place by pumping or other means.

[0052] In this embodiment, when the turbine assembly 100 is running, when water tries to flow through the gap between the rotating parts and the stationary parts, it will be blocked by the multi-layer C-shaped belt 300, thereby effectively preventing water leakage. Even after a long period of operation, the C-shaped belt 300 may leak in a small area due to wear, the pressure pad water tank 400 and its drainage pipe 401 can also promptly discharge this part of the water flow to avoid damage to the equipment.

[0053] Pressure sensors are installed inside the pressure pad tank 400 to continuously monitor pressure changes inside the tank. These sensors are usually highly accurate and stable, providing accurate data feedback at different stages of turbine operation. When the pressure sensor detects an abnormal increase or decrease in internal pressure, it immediately sends a signal to the control system.

[0054] After receiving the data from the pressure sensor, the control system will analyze it according to the preset algorithms and logic. If the detected pressure value exceeds the set safety threshold, the control system will immediately take appropriate measures. For example, the control system can automatically adjust the operating parameters of the turbine, reduce the load or increase the cooling water flow to reduce the internal pressure. If the pressure continues to rise to a dangerous level, the control system may trigger an emergency shutdown procedure to prevent more serious damage.

[0055] A drain pipe 401 with a valve device is added to the design, which makes it easy to cut off the connection between the pressure pad water tank 400 and the outside world during maintenance, prevents external impurities from entering the device, and simplifies the maintenance process. At the same time, since the drain pipe 401 is connected to the main drainage channel of the turbine assembly 100, the excess water flow caused by the fault can be effectively managed without worrying about the water being discharged into the environment in a disorderly manner.

[0056] Importantly, it should be noted that the construction and arrangement of the present application shown in a number of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible, for example, the size, scale, structure, shape and proportion of various elements, and parameter values ​​such as temperature, pressure, etc., mounting arrangements, use of materials, color, directional changes, etc., without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure of the execution function described herein, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to numerous modifications still falling within the scope of the appended claims.

[0057] Furthermore, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment may not be described, i.e., those features that are not relevant to the best mode presently contemplated for carrying out the invention or those features that are not relevant to implementing the invention.

[0058] It should be understood that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but for those of ordinary skill having the benefit of this disclosure, the development effort will be a routine task of design, fabrication, and production without undue experimentation.

[0059] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A bulb tubular turbine main shaft seal, characterized in that: include, A water turbine assembly (100) comprising a water turbine main shaft (101) and a sealing bushing (102) installed outside the water turbine main shaft (101), wherein the sealing bushing (102) is used to provide a preliminary seal between the water turbine main shaft (101) and a fixed component (103); A cushion box (200) surrounds the outside of the sealing bushing (102), wherein the cushion box (200) is fixed to a fixed component (103) of the turbine by means of bolts or snaps; A C-shaped belt (300) is installed between the sealing bushing (102) and the cushion box (200) by winding layer by layer in a spiral staggered manner, and a certain overlapping area is formed between two adjacent layers of the C-shaped belt (300).

2. The bulb-type tubular turbine main shaft seal according to claim 1, characterized in that: The C-shaped belt (300) is installed in a multi-layer staggered winding manner, wherein each layer is fixed to each other by a special adhesive or a mechanical fixing member.

3. The bulb-type tubular turbine main shaft seal according to claim 2, characterized in that: The installation angle of the C-shaped belt (300) ensures that the contact surface between it and the sealing bushing (102) is perpendicular to the water flow direction.

4. The bulb-type tubular turbine main shaft seal according to claim 3, characterized in that: The material of the C-shaped belt (300) is selected from any one or more combinations of polyurethane, rubber or synthetic fiber materials.

5. The bulb-type tubular turbine main shaft seal according to claim 1, characterized in that: A pressure pad water tank (400) is provided on one side of the C-shaped circumference belt (300), and the interior of the pressure pad water tank (400) is a hollow structure.

6. The bulb-type tubular turbine main shaft seal according to claim 5, characterized in that: At least one drainage pipe (401) is provided on the outer ring of the pressure cushion water tank (400); the drainage pipe (401) is fixed to the pressure cushion water tank (400) by welding or threaded connection; and a waterproof sealing ring is provided on the outer side of the drainage pipe (401).

7. The bulb-type tubular turbine main shaft seal according to claim 6, characterized in that: The pressure cushion water tank (400) is connected to a cavity formed between the sealing bushing (102) and the cushion box (200), and water flowing out of the gap of the C-shaped belt (300) can enter the pressure cushion water tank (400) through the cavity.

8. The bulb-type tubular turbine main shaft seal according to claim 7, characterized in that: The pressure pad water tank (400) further comprises a pressure sensor for monitoring the change of water pressure inside the pressure pad water tank (400) and issuing an alarm signal when the pressure exceeds a preset threshold value. The pressure sensor is connected to the control system via a cable or wirelessly.

9. The bulb-type tubular turbine main shaft seal according to claim 8, characterized in that: The drain pipe (401) is provided with a valve device, which can be closed during the shutdown and maintenance of the unit to prevent external impurities from entering the pressure pad water tank (400).

10. The bulb-type tubular turbine main shaft seal according to claim 9, characterized in that: The drainage pipe (401) is connected to the drainage pipe (401) of the turbine assembly (100), so that the water discharged from the pressure pad water tank (400) is merged into the main drainage channel.

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