Quick start turbine governing valve structure

Abstract

The application provides a quick start turbine valve structure, which comprises a valve housing, a valve seat, a valve rod and a valve cover, the valve housing comprises an inlet and an outlet, the valve housing comprises a first steam channel connecting the inlet and the outlet and a second steam channel connecting the inlet and the first steam channel, the valve seat is located in the first steam channel, the valve cover is connected to the valve housing, one end of the valve rod extends into the valve seat through the valve, the other end of the valve rod is provided with an actuator, the valve seat is provided with a plurality of steam window groups connecting the first steam channel and the outlet and connecting the first steam channel and the second steam channel, the valve rod is provided with a plurality of valve petals, and the actuator drives the valve rod to move so that the valve petals block or conduct the steam in the first steam channel and the steam in the second steam channel to the outlet; the application has the advantages that the requirement of quick start of the unit can be met, and the unit can be stably operated in a large steam parameter range.

Description

Technical Field

[0001] The present invention relates to the field of steam turbines, and more particularly to a quick-start steam turbine regulating valve structure. Background Art

[0002] The function of a steam turbine's regulating valve is to adjust the steam flow entering the turbine to match the turbine load and meet operational requirements. Conventional steam turbine regulating valves utilize a lift-type structure, consisting of a regulating valve, a transmission mechanism, and an oil motor. The regulating valve includes a valve stem, a valve beam, a valve disc, and a valve seat. A steam turbine is typically equipped with four or five regulating valves, whose opening sequence and lift are controlled based on actual operating conditions. This regulating structure is complex, requiring high assembly and adjustment requirements. Furthermore, due to space limitations, it is difficult to meet the requirements for rapid turbine startup. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the object of the present invention is to provide a quick start steam turbine valve regulating structure, which can meet the requirements of quick start of the unit and can operate stably within a larger steam parameter range.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A quick-start steam turbine valve regulating structure includes a valve regulating housing, a valve seat, a valve stem and a valve cover, the valve regulating housing includes a steam inlet and a steam outlet, the valve regulating housing includes a first steam channel connecting the steam inlet and the steam outlet, and a second steam channel connecting the steam inlet and the first steam channel, the valve seat is located in the first steam channel, the valve cover is connected to the valve regulating housing, one end of the valve stem extends through the valve into the valve seat, the other end of the valve stem is provided with an actuator, the valve seat is provided with multiple groups of steam windows connecting the first steam channel and the steam outlet and connecting the first steam channel and the second steam channel, the valve stem is provided with multiple groups of valve flaps, and the actuator drives the valve stem to move so that the valve flap blocks or guides the steam in the first steam channel and the steam in the second steam channel to flow to the steam outlet.

[0006] Furthermore, the valve seat includes an upper guide portion and a lower guide portion, both of which are provided with steam ventilation windows, and the valve stem includes two sets of valve flaps, and the valve stem includes an initial state and a blocking state. When the valve stem is in the initial state, the upper surface of the valve flap is aligned with the bottom of the corresponding steam ventilation window, and when the valve stem is in the blocking state, the upper surface of the valve flap is aligned with the top of the corresponding steam ventilation window.

[0007] Furthermore, the steam ventilation window includes an upper window and a lower window, the upper window is connected to the lower window, the upper window is triangular, and the lower window is rectangular.

[0008] Further, when the valve stem moves from the initial state to the blocking state, the total stroke of the valve stem is H. The ratio of the height of the upper window to the total stroke of the valve stem is 2:3, the ratio of the height of the lower window to the total stroke of the valve stem is 1:3, the ratio of the straight-line distance between the two bottom corners on both sides of the upper window to the straight-line distance between the two bottom sides on both sides of the lower window is 3:8, and the ratio of the area of the region of the upper window to the area of the region of the lower window is 3:8.

[0009] Further, there are 3 groups of steam vent windows on the side walls of both the upper guiding part and the lower guiding part. The included angle between each group of steam vent windows on the upper guiding part and each group of steam vent windows on the lower guiding part is 120°.

[0010] Further, a guiding bushing and a sealing ring are also sleeved on the valve stem located inside the valve cover.

[0011] Further, a leakage interface is provided on one side of the valve cover, and the leakage interface extends to the valve stem on one side.

[0012] The beneficial effects of the present invention: The valve stem is controlled to move up and down to change the steam flow rate entering the unit. Specifically, to meet the requirement of quick start, when the steam turbine is in the hot standby state, the governing valve is in the fully open state. The steam turbine instantly increases its speed, and the actuator acts to change the opening degree of the governing valve according to the control requirements. In order to make the unit operate stably within a large range of steam parameters, the lower part of the governing valve window is designed as a rectangle to increase the steam intake of the unit and meet the demand for low parameter operation of the unit; the upper part is designed as a triangle. The purpose is that when the unit starts quickly, the valve stem of the governing valve quickly responds and moves upward and closes to the triangular area, quickly controlling the steam intake and preventing the unit from overspeed and triggering the trip protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is the internal structure diagram of the present invention;

[0014] Figure 2 is the top view of the valve seat in the present invention;

[0015] Figure 3 is Figure 2 the cross-sectional view of

[0016] Figure 4 is the schematic diagram of the steam vent window in the present invention;

[0017] Figure 5 is the structure diagram of the valve stem in the present invention.

[0018] Figure numerals: 1. regulating valve housing; 2. valve seat; 21. upper guide part; 22. lower guide part; 3. valve stem; 31. valve disc; 4. valve cover; 5. steam inlet; 6. steam outlet; 7. first steam channel; 8. second steam channel; 9. steam window; 91. upper window; 92. lower window; 10. guide bushing; 11. sealing ring; 12. leakage interface; 13. connecting nut. DETAILED DESCRIPTION

[0019] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments. Identical components are denoted by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, and the terms "bottom," "top," "inner," and "outer" refer to directions toward or away from the geometric center of a particular component, respectively.

[0020] Since the existing regulating structure is relatively complex, the requirements for assembly and adjustment are high, and it is limited by space size and difficult to meet the requirements of rapid start-up of the steam turbine, the present invention designs this rapid start-up steam turbine regulating valve structure, the specific structure is as follows Figure 1 As shown, the valve body comprises a regulating valve housing 1, a valve seat 2, a valve stem 3 and a valve cover 4. The regulating valve housing 1 comprises a steam inlet 5 and a steam outlet 6. The regulating valve housing 1 comprises a first steam passage 7 connecting the steam inlet 5 and the steam outlet 6 and a second steam passage 8 connecting the steam inlet 5 and the first steam passage 7 (as shown in FIG. Figure 1 It can be seen that the first steam channel 7 is vertically downward through the bottom of the regulating valve housing 1, and the second steam channel 8 is located on one side of the first steam channel 7), the valve seat 2 is located in the first steam channel 7, the valve cover 4 is connected to the regulating valve housing 1 (interference fit), one end of the valve stem 3 passes through the valve and extends into the valve seat 2, and the other end of the valve stem 3 is provided with an actuator (the valve stem 3 is connected to the actuator at the lower end through a connecting nut 13), and the valve seat 2 is provided with multiple groups of steam windows connecting the first steam channel 7 with the steam outlet 6 and connecting the first steam channel 7 with the second steam channel 8. Port 9, a plurality of valve flaps 31 are provided on the valve stem 3, and the actuator drives the valve stem 3 to move so that the valve flap 31 blocks or conducts the steam in the first steam channel 7 and the steam in the second steam channel 8 to flow to the steam outlet 6. Its function is that after receiving the speed control signal, the actuator controls the valve stem 3 to move up and down to change the steam flow entering the unit. Specifically, in order to meet the requirements of rapid startup, the regulating valve is in a fully open state in the hot standby state of the steam turbine, and the steam turbine speeds up instantly. The actuator acts to change the regulating valve opening according to the control requirements.

[0021] like Figure 2 and Figure 3 As shown, specifically, the valve seat 2 includes an upper guide portion 21 and a lower guide portion 22, and both the upper guide portion 21 and the lower guide portion 22 are provided with a steam window 9, as shown in FIG. Figure 5As shown, the valve stem 3 includes two sets of valve flaps 31 (the relative friction parts of the valve stem 3 are specially heat treated. In addition, with this valve regulating structure, the airflow force on the valve stem 3 during the operation is relatively balanced, and the stability of the operation of the valve stem 3 is better). The valve stem 3 includes an initial state and a blocking state. When the valve stem 3 is in the initial state, the upper surface of the valve flap 31 is aligned with the bottom of the corresponding steam window 9. When the valve stem 3 is in the blocking state, the upper surface of the valve flap 31 is aligned with the top of the corresponding steam window 9. The initial state is the fully open state, and the ventilation window is fully open at this time. The maximum amount of steam enters from the steam inlet 5, passes through the first steam duct 7 and the second steam duct 8 respectively, and flows to the steam outlet 6. The steam turbine speeds up instantly, and the actuator changes the valve opening according to the control requirements. The blocking state is that after the valve stem 3 moves upward, the valve disc 31 blocks the steam. The valve disc 31 at the upper guide part 21 blocks the steam in the first steam duct 7, preventing the steam from flowing from the steam window 9 of the upper guide part 21 to the steam outlet 6. The valve disc 31 at the lower guide part 22 blocks the steam in the second steam duct 8, preventing the steam in the second steam duct 8 from flowing from the steam window 9 of the lower guide part 22 to the outlet.

[0022] like Figure 2 As shown, the side walls of the upper guide portion 21 and the side walls of the lower guide portion 22 each include three groups of steam windows 9. The angle between each group of steam windows 9 on the upper guide portion 21 and each group of steam windows 9 on the lower guide portion 22 is 120 degrees. Figure 4 As shown, the steam window 9 includes an upper window 91 and a lower window 92. The upper window 91 is connected to the lower window 92. The upper window 91 is triangular and the lower window 92 is rectangular. Since the steam control of the steam turbine is relatively strict, the size ratio of the steam window 9 is relatively important. Specifically, when the valve stem 3 moves from the initial state to the blocked state, the total stroke of the valve stem 3 is H, the ratio of the height of the upper window 91 to the total stroke of the valve stem 3 is 2:3, the ratio of the height of the lower window 92 to the total stroke of the valve stem 3 is 1:3, and the ratio of the straight-line distance between the bottom corners of the upper window 91 and the straight-line distance between the bottom sides of the lower window 92 is 3: 8. The area ratio of the upper window 91 to the lower window 92 is 3:8, where H is equal to the total stroke of the regulating valve stem 3, C = 2 / 3H, B = 3 / 8A, and the steam pressure range of the unit during normal operation is 7.6 bar to 86 bar. In order to make the unit operate stably within a larger steam parameter range, the lower part of the regulating valve window is designed to be rectangular to increase the steam intake of the unit and meet the requirements of low parameter operation of the unit; the purpose of designing the upper part to be triangular is that when the unit is quickly started, the regulating valve stem 3 responds quickly and moves upward and closes to the triangular area, quickly controlling the steam intake to prevent the unit from overspeeding and triggering the trip protection.

[0023] like Figure 1As shown, a guide bushing 10 is also provided on the valve stem 3 located in the valve cover 4, and a gas leakage interface 12 is provided on one side of the valve cover 4. The gas leakage interface 12 extends to one side to the valve stem 3, and a sealing ring made of flexible graphite is filled at the lower end of the bushing. If necessary, the pressing force of the sealing ring can be increased by the pressure cap to prevent or reduce the gas leakage of the valve stem 3. The gas leakage of the valve stem 3 is led to the steam leakage pipeline through the gas leakage interface 12K on the valve cover 4 through the external pipeline.

[0024] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that improvements and modifications that do not depart from the principles of the present invention are within the scope of protection of the present invention.

Claims

1. A quick start steam turbine valve regulating structure, characterized by: The invention comprises a regulating valve housing (1), a valve seat (2), a valve stem (3) and a valve cover (4); the regulating valve housing (1) comprises a steam inlet (5) and a steam outlet (6); the regulating valve housing (1) comprises a first steam passage (7) connecting the steam inlet (5) and the steam outlet (6) and a second steam passage (8) connecting the steam inlet (5) and the first steam passage (7); the valve seat (2) is located in the first steam passage (7); the valve cover (4) is connected to the regulating valve housing (1); one end of the valve stem (3) passes through the valve The valve stem (3) extends into the valve seat (2), and the other end of the valve stem (3) is provided with an actuator. The valve seat (2) is provided with multiple groups of steam windows (9) connecting the first steam channel (7) and the steam outlet (6) and connecting the first steam channel (7) and the second steam channel (8). The valve stem (3) is provided with multiple groups of valve flaps (31). The actuator drives the valve stem (3) to move so that the valve flaps (31) block or conduct the steam in the first steam channel (7) and the steam in the second steam channel (8) to flow to the steam outlet (6). The steam ventilation window (9) includes an upper window (91) and a lower window (92), wherein the upper window (91) is in communication with the lower window (92), the upper window (91) is in a triangular shape, and the lower window (92) is in a rectangular shape; A guide bushing (10) and a sealing ring (11) are sleeved on the valve stem (3) located in the valve cover (4).

2. The quick start steam turbine valve regulating structure according to claim 1, characterized in that: The valve seat (2) includes an upper guide portion (21) and a lower guide portion (22), and the upper guide portion (21) and the lower guide portion (22) are both provided with a steam ventilation window (9). The valve stem (3) includes two groups of valve flaps (31), and the valve stem (3) includes an initial state and a blocking state. When the valve stem (3) is in the initial state, the upper surface of the valve flap (31) is aligned with the bottom of the corresponding steam ventilation window (9), and when the valve stem (3) is in the blocking state, the upper surface of the valve flap (31) is aligned with the top of the corresponding steam ventilation window (9).

3. The rapid start-up steam turbine valve regulating structure according to claim 2, characterized in that: When the valve stem (3) moves from the initial state to the blocked state, the total stroke of the valve stem (3) is H, the ratio of the height of the upper window (91) to the total stroke of the valve stem (3) is 2:3, the ratio of the height of the lower window (92) to the total stroke of the valve stem (3) is 1:3, the ratio of the straight-line distance between the bottom corners of the upper window (91) and the straight-line distance between the bottom edges of the lower window (92) is 3:8, and the ratio of the area of ​​the upper window (91) to the area of ​​the lower window (92) is 3:

8.

4. The rapid start-up steam turbine valve regulating structure according to claim 3, characterized in that: The side wall of the upper guide portion (21) and the side wall of the lower guide portion (22) both include three groups of steam ventilation windows (9), and the angle between each group of steam ventilation windows (9) on the upper guide portion (21) and each group of steam ventilation windows (9) on the lower guide portion (22) is 120°.

5. The rapid start-up steam turbine valve regulating structure according to claim 1, characterized in that: An air leakage interface (12) is provided on one side of the valve cover (4), and the air leakage interface (12) extends to one side to the valve stem (3).

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