A method for operating a tilting pad bearing jacking oil system for a steam turbine and a jacking device

Abstract

The present invention relates to an operation method of a tilting pad bearing jacking oil system and a jacking device for a turbine, the operation method comprising: establishing a jacking oil system operation database between bearing working conditions, optimal oil pressure, pad temperature and shaft vibration value; during the operation of the unit, judging whether the pad temperature in the bearing is within a preset threshold range; if so, shutting down the jacking oil system and keeping the bearing in the original operation mode; if greater than, judging whether the optimal oil pressure is recorded in the operation database; if not recorded, opening the jacking oil system so that the pad temperature is within the preset threshold range, obtaining the optimal oil pressure, and recording the above-mentioned optimal oil pressure and the pad temperature and shaft vibration value corresponding to the optimal oil pressure into the operation database; if recorded, opening the jacking oil system so that the oil film pressure reaches the optimal oil pressure and keeps running. The adjustment method in the present invention can meet the requirements of stable operation of the shaft system of units with frequent and rapid load changes in new power systems.

Description

Technical Field

[0001] The invention relates to the technical field of steam turbines, and in particular to an operating method for a tilting pad bearing jacking oil system of a steam turbine and a jacking device. Background Art

[0002] Tilting pad bearings are generally used in steam turbines. They are swing-pad bearings. The tilting pad bearings are equipped with a jacking oil system during use. The jacking oil system can provide lubricating oil to the bearings to lift up the rotor and avoid direct contact between the rotor and the pads to cause friction. However, in the prior art, the jacking oil system is only used during the startup process of the steam turbine. During the daily operation of the unit, the jacking oil system is exited and the lubricating oil temperature is controlled by the lubricating oil system.

[0003] However, in the new power system, the role of coal-fired power units is changing from the main power generation to the peak load regulation of new energy sources, which leads to the ultra-low load and rapid load change operation of the units. The oil film pressure is unstable, and the output of the lubricating oil pump is small. In addition, the lubricating oil injection direction is often tangential to the rotor rotation direction. The top shaft pressure is insufficient. When the pressure is insufficient, it is easy to cause oil film rupture and bearing wear, bearing temperature rise, and even cause bearing burning, which affects the rotation of the rotating shaft in the turbine and requires frequent maintenance, which increases the maintenance cost. Based on the above problems, the present invention provides a method for operating a top shaft oil system for a tilting pad bearing of a turbine and a top shaft device. Summary of the invention

[0004] The present invention provides a method for operating a tilting pad bearing jacking oil system for a steam turbine and a jacking device, which have a large oil pressure adjustment range and a fast speed, are conducive to meeting the requirements for stable operation of shaft systems with frequent and rapid load changes of units in new power systems, and improve the safety of the units.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for regulating oil film pressure using a jacking oil system, comprising:

[0007] Establishing a jacking oil system operation database between bearing working conditions, optimal oil pressure, pad temperature and shaft vibration values, wherein the jacking oil system operation database is a blank database when initially established;

[0008] During the operation of the unit, determine whether the temperature of the bearing pad is within the preset threshold range;

[0009] If the temperature of the pad is within the preset threshold range, the top shaft oil system is in a closed state, and the bearing maintains the original operation mode;

[0010] If the temperature of the pad is greater than the maximum value of the preset threshold, it is determined whether the optimal oil pressure under the operating condition of the bearing being operated is recorded in the jacking oil system operation database;

[0011] If the optimum oil pressure is not recorded, the jacking oil system is turned on so that the pad temperature is within the preset threshold range, and the oil pressure corresponding to the minimum shaft system vibration value is taken as the optimum oil pressure, and the optimum oil pressure and the pad temperature and shaft system vibration value corresponding to the optimum oil pressure are recorded in the jacking oil system operation database under the bearing working condition;

[0012] If the optimum oil pressure is recorded, the top shaft oil system is opened so that the oil film pressure reaches the optimum oil pressure and is put into operation.

[0013] Preferably, during the operation of the unit, when the temperature of the bearing pad is greater than the maximum value of the preset threshold value, and the optimal oil pressure is recorded in the jacking oil system operation database, the jacking oil system is started so that the oil film pressure reaches the optimal oil pressure and continues to operate. After the temperature of the bearing pad is stable, the jacking oil system operation database is updated, and the updating step includes:

[0014] First, determine whether the temperature of the tile segment is within the preset threshold range;

[0015] If yes, then update the pad temperature and shaft vibration value under the bearing working condition in the jacking oil system operation database;

[0016] If not, start the jacking oil system so that the pad temperature is within the preset threshold range, and obtain the optimal oil pressure corresponding to the minimum shaft system vibration value, and update the above-mentioned optimal oil pressure and the pad temperature and shaft system vibration value corresponding to the optimal oil pressure to the jacking oil system operation database under the bearing operating condition.

[0017] Preferably, after the top shaft oil system operation database is established, during the operation of the unit, at least the optimal oil pressure, shoe temperature and shaft vibration value under one bearing operating condition are recorded, and then it is determined whether the optimal oil pressure under the operating bearing condition is recorded in the top shaft oil system operation database.

[0018] Preferably, the preset threshold range of the tile temperature is the tile operating temperature range specified by the manufacturer when the tile leaves the factory.

[0019] Preferably, the bearing operating conditions are divided according to the unit load and the load variation rate.

[0020] A top shaft device is arranged on a tile supporting a rotor at the bottom of a bearing, is an oil inlet device of a top shaft oil system, and is used based on the above-mentioned operating method, comprises a one-way valve, a transition pipe joint and an oil pipe assembly, the above-mentioned tile is provided with a mounting hole along its axially arranged side wall, the above-mentioned tile is provided with a top shaft oil bag on the side wall facing the rotor, an oil circuit is provided in the above-mentioned tile, the inlet and outlet of the above-mentioned oil circuit are respectively connected to the above-mentioned mounting hole and the above-mentioned top shaft oil bag, the above-mentioned transition pipe joint is installed at the orifice of the above-mentioned mounting hole, the above-mentioned one-way valve is installed in the above-mentioned mounting hole, and the above-mentioned oil pipe assembly is connected to the above-mentioned transition pipe joint.

[0021] Preferably, the transition pipe joint and the tile are integrally cast.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The jacking oil system, which usually only runs during the startup process, is applied to daily operation. Since the jacking oil pump has high power, a large oil pressure adjustment range and high speed, it is conducive to meeting the needs of stable operation of the shaft system of the unit with frequent and rapid load changes in the new power system, and improves the safety of the unit.

[0024] 2. By establishing a blank jacking oil system operation database, during the operation of the unit, the database data can be improved, the oil pressure can be adjusted through the jacking oil system, and the oil pressure can be adjusted using the jacking oil system based on the data recorded in the jacking oil system operation database under the same bearing conditions. This can save a lot of data testing time and testing costs, and the unit can be put into use directly, improved during use and used as a basis for adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A method block diagram of an embodiment of the present invention;

[0027] Figure 2 It is a schematic diagram of the connection between the tile and the top shaft device in the embodiment of the present invention;

[0028] Figure 3 A schematic diagram of a tile in an embodiment of the present invention;

[0029] Figure 4 Schematic diagram of the top shaft oil bag in an embodiment of the present invention.

[0030] Description of reference numerals:

[0031] 1. Tile block; 11. Oil circuit; 12. Mounting hole; 13. Top shaft oil bag; 2. Top shaft device; 21. Transition pipe joint; 22. One-way valve; 23. Oil pipe assembly; 231. Hard pipe; 232. Metal hose; 3. Tile body. DETAILED DESCRIPTION

[0032] 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.

[0033] 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 limiting 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.

[0034] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 present invention can be understood according to specific circumstances.

[0035] The tilting bearing in the steam turbine is equipped with a jacking oil system during use. The jacking oil system is a prior art and generally includes a motor, a high-pressure oil pump, a duplex filter, a plate filter, a pressure relay, a relief valve, a one-way throttle valve and a jacking device arranged on the tile. The high-pressure oil pump is connected to the motor, pressure relay, plate filter and duplex filter. The plate filter is connected to the one-way throttle valve. The plate filter is also connected to a distributor, and the overflow valve is connected to the duplex filter. Specifically, high-pressure oil is provided by the high-pressure oil pump, and the oil filtered by the oil pump and the filter enters the bearing through the jacking device, forming a static oil film between the bearing block and the rotor, jacking up the rotor, and avoiding direct contact and friction between the rotor and the bearing block. However, in the prior art, the jacking oil system is only used in the steam turbine during the startup process. The jacking oil system is withdrawn during the daily operation of the unit, and the lubricating oil temperature is controlled by the lubricating oil system. However, the output of the lubricating oil pump in the lubricating oil system is small, and the lubricating oil injection direction is often tangential to the rotor rotation direction. The jacking pressure is insufficient, which can easily lead to oil film rupture and bearing wear, increase the bearing temperature, and even cause bearing burning, which cannot meet the ultra-low load and rapid load change operation of the unit.

[0036] The embodiment of the present invention provides a method for operating a tilting pad bearing jacking oil system of a steam turbine, such as Figure 1 As shown, specifically including:

[0037] First, establish a top shaft oil system operation database between bearing conditions, optimal oil pressure, shoe temperature and shaft vibration values. Moreover, when it is initially established, the top shaft oil system operation database is a blank database. Later, it is necessary to obtain the operating data of bearing conditions, optimal oil pressure, shoe temperature and shaft vibration values ​​during the operation of the unit, and record this data in the top shaft oil system operation database to realize the filling of data in the top shaft oil system operation database, and use it as reference data for the subsequent bearing condition operation.

[0038] Later, during the operation of the unit, it is first determined whether the temperature of the bearing pads is within the preset threshold range; if the temperature of the bearing pads is within the preset threshold range, it can be seen that the oil film pressure is stable, the oil film can be kept running stably, the top shaft oil system can be in a closed state, and the bearing can continue to run in the original mode; if the temperature of the bearing pads exceeds the standard, that is, it is greater than the maximum value of the preset threshold, it can be seen that the temperature of the bearing pads has increased due to insufficient oil film pressure, thin oil film, and wear of the bearing pads. At this time, the oil pressure needs to be adjusted to reduce the temperature of the bearing pads. Before adjustment, it is necessary to determine whether the optimal oil pressure under the operating condition of the bearing is recorded in the operating database of the top shaft oil system, as follows: If the optimal oil pressure is not recorded, oil needs to be supplied, and the temperature of the bearing pads under this operating condition is reduced to within the preset threshold range. Specifically, the top shaft oil system is turned on, oil is supplied to the bearing, and the top shaft oil pressure is adjusted , until the pad temperature is within the preset threshold range, and the oil pressure corresponding to the minimum shaft vibration value is taken as the optimal oil pressure. At this time, the rotor runs most stably and the pad temperature meets the requirements. Then, the optimal oil pressure and the pad temperature and shaft vibration value corresponding to the optimal oil pressure are obtained, and recorded in the top shaft oil system operation database under the bearing working condition, thereby realizing the improvement of the top shaft oil system operation database. Finally, as the running time of the unit increases, the top shaft oil system operation database will record the optimal oil pressure corresponding to the bearing working condition when all pads are overheated and the pad temperature and shaft vibration value corresponding to the optimal oil pressure to make its data complete; if the optimal oil pressure is recorded, the top shaft oil system is directly turned on to supply oil to the bearing so that the oil film pressure value reaches the recorded optimal oil pressure value, and this state can be maintained, which can reduce the pad temperature to within the preset threshold range and the bearing can run stably.

[0039] In the adjustment method, a top shaft oil system operation database is first established. In the initial stage of establishment, it is a blank database. Then, during the operation of the unit, the data in the top shaft oil system operation database is adjusted and improved. Based on the data that has been recorded in the top shaft oil system operation database under the same bearing working conditions, the oil pressure in the bearing operation process is adjusted through the top shaft oil system to achieve the optimal oil pressure, so that the temperature of the bearing pad is stabilized within the preset threshold range, thereby saving a lot of data testing time and testing costs; furthermore, the top shaft oil system, which is usually only operated during the startup process, is used in daily operation, and a startup and oil pressure adjustment method is established. Since the top shaft oil pump has high power, a large oil pressure adjustment range and fast speed, it is conducive to meeting the needs of stable operation of the shaft system of the unit with frequent and rapid load changes in the new power system, thereby improving the safety of the unit.

[0040] It should be noted that after the jacking oil system supplies oil to the bearing, even if the jacking oil system is closed, the lubricating oil in the bearing will not flow back, but will remain in the bearing; and the jacking oil system adjusts the oil pressure by point adjustment, that is, a fixed value is adjusted each time (the specific adjustment value is determined by the operator), and it runs for a period of time (about 1 minute), and then the corresponding pad temperature and shaft vibration value will be obtained. When the pad temperature is within the preset threshold range, the oil pressure is adjusted by adjusting the fixed value to obtain multiple shaft vibration values, and then the oil pressure with the smallest shaft vibration value is taken as the optimal oil pressure, and the oil pressure is adjusted to the optimal oil pressure through the jacking oil system; and the above-mentioned pad temperature, oil pressure and shaft vibration values ​​can be directly obtained in the power plant measurement system, which belongs to the existing technology and will not be repeated.

[0041] Furthermore, due to changes such as aging and maintenance of the unit, the optimal oil pressure corresponding to the same pad temperature may change, so it is necessary to update and adjust the jacking oil system operation database so that the optimal oil pressure recorded in the jacking oil system operation database always adapts to the actual situation of the unit. The specific steps include:

[0042] During the operation of the unit, when the pad temperature is greater than the maximum value of the preset threshold and the optimal oil pressure is recorded in the top shaft oil system operation database, the top shaft oil system is turned on to supply oil to the bearing so that the oil film pressure reaches the optimal oil pressure and continues to run for a period of time. After the pad temperature stabilizes (the fluctuation range does not exceed 5%), first determine whether the pad temperature is within the preset threshold range, as follows: If the pad temperature is within the preset threshold range, then re-obtain the pad temperature and the shaft system vibration value, and then re-update the above-mentioned pad temperature and shaft system vibration value to the bearing operating condition in the top shaft oil system operation database; if the pad temperature is not within the preset threshold range, continue to adjust the oil pressure of the opened top shaft oil system to supply oil to the bearing until the pad temperature is within the preset threshold range, and obtain the optimal oil pressure corresponding to the minimum shaft system vibration value, and update the above-mentioned optimal oil pressure and the pad temperature and shaft system vibration value corresponding to the optimal oil pressure to the bearing operating condition in the top shaft oil system operation database.

[0043] Specifically, after the top shaft oil system operation database is established, during the operation of the unit, at least the optimal oil pressure under one bearing working condition and the pad temperature and shaft vibration value corresponding to the optimal oil pressure are entered, and then it is determined whether the optimal oil pressure under the operating bearing condition is recorded in the top shaft oil system operation database, thereby avoiding the situation where there is no data in the blank database and judging whether the optimal oil pressure is recorded, thereby saving unnecessary judgment steps.

[0044] Specifically, the preset threshold range of the tile temperature is the tile operating temperature range specified by the manufacturer when the tile leaves the factory.

[0045] Specifically, the bearing working conditions are divided according to the unit load and the load change rate. For example, the operating load range of a unit is P0~P n , the load rate range is a0%-a n %, the load and variable load rate range can be divided into several discrete points, P0, P2, P3, ...P n , a0%, a1%, a2%, ...a n %, and the intervals are △P and △a respectively. Then the working conditions of the first load are divided as shown in Table 1.

[0046] Table 1

[0047] The working condition classification of the second load is shown in Table 2.

[0048] Table 2

[0049] The division of bearing working conditions for other loads is similar. Through the division of bearing working conditions, the data in actual operation can be classified into the corresponding bearing working condition points, thereby realizing operation cluster analysis and providing a basis for adjusting the top shaft oil pressure.

[0050] Specifically, the present invention also discloses a jacking device, which is used based on the above-mentioned operation method to ensure oil pressure, such as Figure 2-Figure 4 As shown, it includes a one-way valve 22, a transition pipe joint 21 and an oil pipe assembly 23. The side wall of the tile 1 along its axial direction is provided with a mounting hole 12, and the side wall of the tile 1 facing the rotor is provided with a top shaft oil bag 13. The tile 1 is provided with an oil circuit 11, and the inlet and outlet of the oil circuit 11 are respectively connected with the mounting hole 12 and the top shaft oil bag 13. The transition pipe joint 21 is installed at the orifice of the mounting hole 12, and the one-way valve 22 is installed in the mounting hole 12. One end of the oil pipe assembly 23 is connected to the transition pipe joint 21, and the other end is connected to the double filter in the top shaft oil system to form a complete oil supply system. The one-way valve 22 is set in the mounting hole 12 to make the lubricating oil flow in one direction, so as to avoid the lubricating oil in the bearing from flowing back after the high-pressure oil pump in the oil supply device stops working, so as to ensure the oil pressure in the top shaft oil bag 13, thereby ensuring the pressure of the static pressure oil film formed between the tile 1 and the rotor, and avoiding the collision and friction between the tile 1 and the rotor.

[0051] Preferably, the oil pipe assembly 23 includes a connected hard pipe 231 and a metal hose 232, wherein the hard pipe 231 is connected to the transition pipe joint 21, and the metal soft pipe is connected to the filter, so that the transition pipe joint 21 and the tile 1 have free movement space, so that the tile 1 has swing space and will not affect the swing of the tile 1.

[0052] Because the shoe 1 will have a slight swing during the operation of the bearing, and the transition joint of the traditional top shaft device 2 and the shoe 1 are connected by threads, it is easy to cause the connection between the two to loosen, accompanied by pressure outward tilt, resulting in insufficient oil pressure on the top shaft, so that the oil film between the rotor and the shoe 1 will be thinner, or even in contact, and the two will wear, causing a series of operating accidents. Preferably, in this embodiment, the transition pipe joint 21 and the shoe 1 are cast as one piece to avoid relative operation between the two, so that the transition pipe joint 21 and the shoe 1 move synchronously, ensuring the reliability and stability of the connection.

[0053] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A method for operating a tilting pad bearing jacking oil system of a steam turbine, characterized in that: include: Establishing a jacking oil system operation database between bearing working conditions, optimal oil pressure, pad temperature and shaft vibration values, wherein the jacking oil system operation database is a blank database when initially established; During the operation of the unit, determine whether the temperature of the bearing pad is within the preset threshold range; If the temperature of the pad is within the preset threshold range, the top shaft oil system is in a closed state and the bearing maintains the original operation mode; If the temperature of the pad is greater than the maximum value of the preset threshold, it is determined whether the optimal oil pressure under the operating condition of the bearing being operated is recorded in the jacking oil system operation database; If the optimum oil pressure is not recorded, the jacking oil system is turned on so that the pad temperature is within the preset threshold range, and the oil pressure corresponding to the minimum shaft system vibration value is taken as the optimum oil pressure, and the optimum oil pressure and the pad temperature and shaft system vibration value corresponding to the optimum oil pressure are recorded in the jacking oil system operation database under the bearing working condition; If the optimum oil pressure is recorded, the top shaft oil system is opened so that the oil film pressure reaches the optimum oil pressure and is put into operation.

2. The operating method according to claim 1, characterized in that: During the operation of the unit, when the temperature of the bearing block is greater than the maximum value of the preset threshold value, and the optimal oil pressure is recorded in the jacking oil system operation database, the jacking oil system is turned on to make the oil film pressure reach the optimal oil pressure and continue to operate. After the temperature of the bearing block is stable, the jacking oil system operation database is updated. The updating steps include: First, determine whether the temperature of the tile segment is within the preset threshold range; If yes, then update the pad temperature and shaft vibration value under the bearing working condition in the jacking oil system operation database; If not, start the jacking oil system so that the pad temperature is within the preset threshold range, and obtain the optimal oil pressure corresponding to the minimum shaft system vibration value, and update the above-mentioned optimal oil pressure and the pad temperature and shaft system vibration value corresponding to the optimal oil pressure to the jacking oil system operation database under the bearing operating condition.

3. The operating method according to claim 1, characterized in that: After the jacking oil system operation database is established, during the operation of the unit, at least the optimal oil pressure, shoe temperature and shaft vibration value under one bearing working condition are entered, and then it is determined whether the optimal oil pressure under the operating bearing condition is recorded in the jacking oil system operation database.

4. The operating method according to claim 1, characterized in that: The preset threshold range of the tile temperature is the tile operating temperature range specified by the manufacturer when the tile leaves the factory.

5. The operating method according to claim 1, characterized in that: Bearing operating conditions are divided according to unit load and load variation rate.

6. A jacking device, arranged on a pad supporting a rotor at the bottom of a bearing, is an oil inlet device of a jacking oil system, and is used based on the operating method according to any one of claims 1 to 5, characterized in that: It includes a one-way valve, a transition pipe joint and an oil pipe assembly. The side wall of the tile arranged along its axial direction is provided with a mounting hole, the side wall of the tile facing the rotor is provided with a top shaft oil bag, an oil circuit is provided in the tile, the inlet and outlet of the oil circuit are respectively connected to the mounting hole and the top shaft oil bag, the transition pipe joint is installed at the orifice of the mounting hole, the one-way valve is installed in the mounting hole, and the oil pipe assembly is connected to the transition pipe joint.

7. The jacking device according to claim 6, characterized in that: The transition pipe joint is integrally cast with the tile.

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