A large-scale water turbine generator set fixed guide vane protection net and protection method

Abstract

The application discloses a large-scale water turbine generator set fixed guide vane protection net and a use method thereof, which comprises a protection net unit, two ends of the protection net unit are respectively an A end and a B end, the protection net unit is arranged at the bottom of a seat ring and is used for surrounding fixed guide vanes, a tension unit is arranged between the A end and the B end and is used for tensioning and spacing the protection net unit, and an access channel is arranged between the A end and the B end. The installation, dismounting and carrying are simple and convenient, in the system development and design process, researchers ensure the reliability, improve the overall design of the device, simplify the installation process of the device, reduce the weight, so that the whole device greatly reduces the risk in the installation process and is convenient to carry and reduces the installation and dismounting time.

Description

Technical Field

[0001] This invention relates to the field of maintenance technology for large hydro-generator sets, and more specifically to a protective net and method for fixed guide vanes of large hydro-generator sets. Background Technology

[0002] In the maintenance of large hydroelectric generator sets, work inside the spiral casing is essential. Due to its unique structure, the height of the seat ring plane gradually increases from the nose end to the water intake pipe, with a maximum drop of up to 5 meters. The interior of the spiral casing is cold and damp, making wetness and slipperiness a major characteristic of working there. 90% of the work inside the spiral casing is carried out on the seat ring plane, which is approximately 0.7 meters wide. Inwards is the turbine, and outwards is work near the edge. Because of its inherent structure, there is no place to attach safety belts. Traditional safety measures involve first wrapping hemp rope around the fixed guide vanes, and then tying a nylon safety net to the hemp rope for worker protection. However, this method has drawbacks such as complex equipment transportation, cumbersome binding process, low strength, low recycling rate, and weak overall equipment integrity.

[0003] Existing fixed guide vane safety protection methods have the following drawbacks:

[0004] The equipment transfer is complicated. Due to the limitations of handling conditions and the weight of the hemp rope when winding the guide vanes, the hemp rope is transported into the volute in 8 sections, and the safety net is transported into the volute in 5 pieces, totaling 13 units. Each unit weighs about 10 kg, and the labor intensity of the relocation and handling is high.

[0005] The binding process is complicated. Every time a fixed guide leaf is placed, the hemp rope is wrapped around the fixed guide leaf once. There are two layers of hemp rope. After the hemp rope is fixed, the safety net is tied to the hemp rope. Each safety net requires at least 10 binding points. There are a total of 5 safety nets. The total operation time is 3 hours for 6 people.

[0006] The strength is too low; the hemp rope is tightened entirely manually without tools, resulting in low tension. The hemp rope is installed in sections, with connections between sections achieved through knots within the rope itself, leaving the rope completely slack after winding and connecting. Plastic cable ties are used to bind the safety net and hemp rope, but the binding strength is too low. Using wire to bind the safety net and hemp rope is complex and the binding points could easily cause injury to workers.

[0007] The recycling rate is low, and the humid environment inside the casing has an adverse effect on the use of hemp rope and safety net. The service life is generally two years.

[0008] The device lacks overall integrity and needs to be assembled on the guide vanes fixed inside the volute. It also needs to be disassembled after use, which is time-consuming and labor-intensive. Summary of the Invention

[0009] The purpose of this invention is to provide a protective net and method for fixed guide vanes of large hydro-generator sets, in order to solve the technical problems in the background art.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A protective net for fixed guide vanes of a large hydro-generator unit, comprising:

[0012] A protective net unit, with ends A and B respectively at its two ends; the protective net unit is located at the bottom of the seat ring and is used to surround the fixed guide vane;

[0013] A tensioning unit is provided between end A and end B; it is used to tension the protective net unit; and an access channel is provided between end A and end B.

[0014] In some embodiments, the protective net unit includes a plurality of support poles, two main ropes, and a stainless steel mesh; the two main ropes are arranged vertically, and each end of the main rope is provided with a lifting head for cooperating with the tensioning unit; the plurality of support poles are distributed between the two main ropes and are respectively connected to the two main ropes; the stainless steel mesh is connected to the two main ropes, and the plurality of support poles pass through the stainless steel mesh.

[0015] In some embodiments, the plurality of support poles are arranged at equal intervals.

[0016] In some embodiments, the two main ropes are made of stainless steel.

[0017] In some embodiments, the tensioning unit includes two lever hoists and two connecting ropes, wherein the A ends of the two main ropes are fixed to fixed guide vanes, and the B ends of the two main ropes are wound around the seat ring; the two lever hoists are respectively connected to the B ends of the two main ropes, one end of the two connecting ropes is fixed to the fixed guide vane between the A and B ends of the main ropes, and the other end of the two connecting ropes is respectively connected to the upper and lower lever hoists; the fixed guide vane used to fix the A ends of the main ropes and the fixed guide vane used to fix the connecting ropes form an inlet and outlet channel.

[0018] This embodiment also provides a protection method for fixed guide vanes of large hydro-generator sets, which is based on the protective netting for fixed guide vanes of large hydro-generator sets, and includes the following steps:

[0019] Step 1: Wind the upper connecting rope clockwise along the No. 5 fixed guide leaf. After winding it once, insert the hoist head at the traction end of the connecting rope into the hoist head at the other end of the connecting rope, and hang the upper lever hoist into the hoist head at the traction end of the connecting rope. The height of the lower connecting rope is the same as the lower plane of the seat ring. The distance between the upper connecting rope and the lower plane of the seat ring depends on the working conditions.

[0020] Step 2: Fully unfold the protective net unit along the bottom of the volute, with end A of the protective net unit close to the 7# fixed guide vane in the direction of the volute disc valve; use the rope to pull end A of the protective net unit onto the seat ring, and pull the protective net unit into the inside of the seat ring between the 7# and 8# fixed guide vanes. Then, connect end A of the main rope to its own main rope by winding it clockwise around the 6# fixed guide vane. The installation method for the upper and lower main ropes is the same. The height of the lower main rope is the same as the lower plane of the seat ring.

[0021] Step 3: Alternately pull the main rope along the inside of the fixed guide vane to the outside of the seat ring fixed guide vane;

[0022] Step 4: Connect the main rope auger at end B of the protective netting unit to the chain-side hook of the hand-operated hoist, connecting the upper and lower layers respectively;

[0023] Step 5: First tighten the lever hoist of the lower main rope, then tighten the lever hoist of the upper main rope. The tightening force should be such that the main rope between the #8 and #9 fixed guide vanes does not sag.

[0024] The beneficial effects of this invention compared to the prior art are:

[0025] Safe and reliable, the device was comprehensively optimized in terms of details such as the reliability of the main rope, the reliability of the tensioning method, and the reliability of the connecting components during the research process, so as to ensure that the entire device can provide reliable safety under different conditions.

[0026] Installation, disassembly, and transportation are simple and convenient. During the system development and design process, researchers improved the overall design of the device, simplified the installation process, and reduced the weight while ensuring reliability. This greatly reduced the risk of the installation process and made the device easier to transport, reducing installation and disassembly time. The original 13 units were reduced to 2 units, the original weight was reduced from 130 kg to 60 kg, and the original 6 people and 3 hours were reduced to 2 people and 20 minutes. Attached Figure Description

[0027] Figure 1 This is a schematic diagram showing the connection between the protective netting for the fixed guide vanes and the seat ring of a large hydro-generator unit;

[0028] Figure 2 This is a schematic diagram of the structure of the protective netting for the fixed guide vanes of a large hydroelectric generator unit;

[0029] Figure 3 This is a schematic diagram of a protective netting unit;

[0030] Diagram: 1-Lever hoist, 2-Connecting rope, 3-Entry / exit passage, 4-7# fixed guide vane, 5-8# fixed guide vane, 6-Support pole, 7-6# fixed guide vane, 8-5# fixed guide vane, 9-Stainless steel mesh, 100-Sealing ring, 200-Safety net. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0032] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing 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, and therefore should not be construed as a limitation of this application.

[0035] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or display that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or display.

[0036] The following will combine Figures 1-3This application provides a detailed description of a fixed guide vane protection net for a large hydroelectric generator set and its usage method, as described in the embodiments of this application. It is worth noting that the following embodiments are merely illustrative of this application and do not constitute a limitation thereof.

[0037] Example 1:

[0038] See Figures 1-3 As shown, a protective net for fixed guide vanes of a large hydro-generator unit includes: a protective net unit and a tensioning unit. The protective net unit has two ends, A and B, respectively. The protective net unit is located at the bottom of a seat ring 100 and is used to surround the fixed guide vanes. The protective net unit includes several supporting poles 6, two main ropes, and a stainless steel mesh 9. The two main ropes are arranged vertically and are made of stainless steel. Each end of the main rope has a lifting head that cooperates with the tensioning unit. The several supporting poles are distributed between the two main ropes and connected to them respectively. The stainless steel mesh is connected to the two main ropes, and the several supporting poles pass through the stainless steel mesh. The several supporting poles are evenly spaced. U-shaped grooves are formed at the upper and lower ends of the supporting poles. The diameters of the upper and lower main ropes are adapted to the U-shaped grooves, allowing them to be clamped tightly. The main ropes are then secured with bolts. The several supporting poles are evenly spaced. The tensioning unit is located between end A and end B; it is used to tension the protective net unit; an access channel 3 is provided between end A and end B for people and materials to enter and exit.

[0039] Setting up support poles has the following advantages:

[0040] ① Effectively prevents the main rope from sagging due to gravity during installation;

[0041] ② The stainless steel mesh is confined within the range of two support poles to ensure that each section of stainless steel mesh is stretched evenly and that it will not affect adjacent stainless steel mesh when under stress.

[0042] ③ When the safety protection device is disassembled, the support pole can prevent the two main ropes from moving towards the middle due to the shrinkage of the stainless steel mesh, so that the entire device will not be disordered during the unfolding, installation, winding and transportation process.

[0043] In some embodiments, the tensioning unit includes two lever hoists 1 and two connecting ropes 2, wherein the A ends of the two main ropes are fixed to fixed guide vanes, and the B ends of the two main ropes are wound around the seat ring; the two lever hoists are respectively connected to the B ends of the two main ropes, one end of the two connecting ropes is fixed to the fixed guide vane between the A ends and B ends of the main ropes, and the other end of the two connecting ropes is respectively connected to the upper and lower lever hoists; the fixed guide vane used to fix the A ends of the main ropes and the fixed guide vane used to fix the connecting ropes form an inlet and outlet channel.

[0044] Using a chain hoist or lever hoist as a rope tensioning tool provides high tension strength, stable and reliable self-locking function after tensioning, and the self-binding of the chain after tensioning can serve as a second layer of self-locking protection, increasing the binding points between the main rope and the rope net, thus providing strong assurance for the reliability of the device.

[0045] Stainless steel wire rope is used as the main rope, with two layers, upper and lower. It is wrapped around the outside of the fixed guide leaf once and then tightened by hand-operated hoist or lever hoist. Stainless steel mesh is used instead of traditional nylon safety net, providing strong assurance in terms of device strength.

[0046] The entire safety device features a modular design with minimal or no subdivisions. The total weight is kept under 75 kg, and the dimensions are designed to allow entry and exit through the volute door, enabling two people to transfer the device in a single trip. This design provides strong assurance for the overall integrity of the device.

[0047] An innovative installation method allows all components to be installed and stored as a whole outside the volute. When transported to the inside of the volute, no further assembly is required. The components can be directly installed on the guide vane, saving installation time and improving the convenience and ease of operation.

[0048] This embodiment also provides a protection method for fixed guide vanes of large hydro-generator sets, based on a protective net 200 for fixed guide vanes of large hydro-generator sets, including the following steps:

[0049] Step 1: Wind the upper connecting rope clockwise along the 5# fixed guide leaf 8. After winding it once, insert the auger at the traction end of the connecting rope into the auger at the other end of the connecting rope, and hang the upper lever hoist into the auger at the traction end of the connecting rope. The height of the lower connecting rope is the same as the lower plane of the seat ring. The distance between the upper connecting rope and the lower plane of the seat ring depends on the working conditions.

[0050] Step 2: Fully unfold the protective net unit along the bottom of the volute, with end A of the protective net unit close to the 7# fixed guide vane 4 in the direction of the volute disc valve; the installer stands above the seat ring and uses ropes to pull end A of the protective net unit onto the seat ring, and pulls the protective net unit into the inside of the seat ring from between the 7# fixed guide vane 4 and the 8# fixed guide vane 5. Then, the A end of the main rope is wound clockwise around the 6# fixed guide vane 7 and connected to its own main rope. The installation method for the upper and lower main ropes is the same, and the height of the lower main rope is the same as the lower plane of the seat ring.

[0051] Step 3: Two installers alternately pull the main rope along the inside of the fixed guide vane to the outside of the seat ring fixed guide vane;

[0052] Step 4: Connect the main rope auger at end B of the protective netting unit to the chain-side hook of the hand-operated hoist, connecting the upper and lower layers respectively;

[0053] Step 5: First tighten the lever hoist of the lower main rope, then tighten the lever hoist of the upper main rope. The tightening force should be such that the main rope between the #8 and #9 fixed guide vanes does not sag.

[0054] The calculation results, based on on-site usage requirements, must meet the following conditions:

[0055] 1. The main rope must meet the strength requirements for personnel to fasten safety belts, and must be no less than the strength requirements for two people falling simultaneously;

[0056] 2. The tension of the main rope meets the first requirement;

[0057] 3. The wire rope net meets the strength required to prevent people from falling.

[0058] 4. Calculation of stress on the main rope of stainless steel wire rope:

[0059] Applicable Standard: GB / T8918-2006 Steel Wire Ropes for Important Purposes

[0060] Given conditions:

[0061] Nominal diameter of wire rope: D = 8mm;

[0062] From the table, the nominal tensile strength of the wire rope is: R0 = 1570 MPa;

[0063] From the table, the minimum breaking strength coefficient of a specific wire rope is: K' = 0.356;

[0064] From the table, the breaking force conversion factor for a 7×19 strand wire rope is: K0 = 0.85;

[0065] Tensile strength of steel wire: σ b =1500N / mm 2

[0066] An adult's weight: G = 750 N (75 kg);

[0067] Safety factor of the wire rope carrying personnel:

[0068] Key Relationships:

[0069] Minimum breaking strength of wire rope

[0070] Effective breaking force of wire rope T1=K0σ b S=K0σ b (7×19)πd 2 / 4;

[0071] (in )

[0072] Effective use of tension in wire rope

[0073] The number of people that the steel wire rope can carry at the same time is:

[0074] Substituting the data, we get:

[0075] The minimum breaking strength of the wire rope is F0 = 35.77 kN;

[0076] The effective breaking force of the wire rope is T1 = 37.864 kN;

[0077] The effective tensile strength of the wire rope is T2 = 4.207 kN.

[0078] Therefore, the lifting capacity range for a hand chain hoist is 0.42t-3.5t;

[0079] The steel wire rope can support a maximum of N people at a time, which is N = 5.6.

[0080] Steel wire ropes with a minimum breaking strength of 200 kg or more per strand can meet the usage requirements.

[0081] The above description is merely a preferred embodiment of the present invention and is intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for protecting fixed guide vanes of a large hydro-generator unit, characterized in that, This is achieved using a fixed guide vane protection net for large hydro-generator units, which includes: A protective net unit, with ends A and B respectively at its two ends; the protective net unit is located at the bottom of the seat ring and is used to surround the fixed guide vane; A tensioning unit is provided between end A and end B; it is used to tension the protective net unit; an access channel is provided between end A and end B; The protective net unit includes several support poles, two main ropes, and a stainless steel mesh. The two main ropes are arranged vertically, and each end of the main rope is equipped with a lifting head for use with the tensioning unit. The several support poles are distributed between the two main ropes and are connected to the two main ropes respectively. The stainless steel mesh is connected to the two main ropes, and the several support poles pass through the stainless steel mesh. The tensioning unit includes two lever hoists and two connecting ropes. The A ends of both main ropes are fixed to fixed guide vanes, and the B ends of both main ropes are wound around the seat ring. The two lever hoists are respectively connected to the B ends of the two main ropes. One end of each connecting rope is fixed to a fixed guide vane between the A and B ends of the main ropes, and the other end of each connecting rope is connected to the upper and lower lever hoists respectively. An inlet / outlet channel exists between the fixed guide vane used to fix the A ends of the main ropes and the fixed guide vane used to fix the connecting ropes. The method includes the following steps: Step 1: Wind the upper connecting rope clockwise along the No. 5 fixed guide leaf. After winding it once, insert the hoist head at the traction end of the connecting rope into the hoist head at the other end of the connecting rope, and hang the upper lever hoist into the hoist head at the traction end of the connecting rope. The height of the lower connecting rope is the same as the lower plane of the seat ring. The distance between the upper connecting rope and the lower plane of the seat ring depends on the working conditions. Step 2: Fully unfold the protective net unit along the bottom of the volute, with end A of the protective net unit close to the 7# fixed guide vane in the direction of the volute disc valve; use the rope to pull end A of the protective net unit onto the seat ring, and pull the protective net unit into the inside of the seat ring between the 7# and 8# fixed guide vanes. Then, connect end A of the main rope to its own main rope by winding it clockwise around the 6# fixed guide vane. The installation method for the upper and lower main ropes is the same. The height of the lower main rope is the same as the lower plane of the seat ring. Step 3: Alternately pull the main rope along the inside of the fixed guide vane to the outside of the seat ring fixed guide vane; Step 4: Connect the main rope auger at end B of the protective netting unit to the chain-side hook of the hand-operated hoist, connecting the upper and lower layers respectively; Step 5: First tighten the lever hoist of the lower main rope, then tighten the lever hoist of the upper main rope. The tightening force should be such that the main rope between the #8 and #9 fixed guide vanes does not sag.

2. The protection method for fixed guide vanes of a large hydro-generator unit according to claim 1, characterized in that, The supporting uprights are arranged at equal intervals.

3. The protection method for fixed guide vanes of a large hydro-generator unit according to claim 1, characterized in that, The two main ropes are made of stainless steel.

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