A rotating diaphragm for a double extraction steam turbine unit

Abstract

A double-extraction steam turbine rotating baffle, it relates to a steam turbine, it includes a rotating ring, a baffle body and a steam seal body; the rotating ring is an open rotating ring without a balance cover ring, the outer circumferential surface of the rotating ring extends to be nearly flush with the outer circumferential surface of the baffle body; a plurality of guide blades are arranged circumferentially on the end surface of the rotating ring, which are divided into a large-head guide blade group and a small-head guide blade group with different pitches, the large-head guide blade group and the small-head guide blade group are alternately arranged, and the small-head guide blade group is centrally symmetrically distributed on both sides of the vertical center plane, two adjacent guide blades are a rotating ring steam channel window, the rotating ring steam channel window corresponds to the baffle steam channel window one by one, when the rotating baffle is completely closed, the guide blades on the small-head guide blade group and the corresponding baffle body steam channel window reserve a minimum flow area window. The present invention improves the reliability and safety of high-speed double-extraction steam turbine units.

Description

Technical Field

[0001] The invention relates to a steam turbine, in particular to a rotating partition of a double-extraction steam turbine unit, and belongs to the field of energy and power. Background Art

[0002] A high-speed double-extraction unit refers to a unit with a turbine speed greater than 3000r / min of a conventional power station generator unit. It is connected to the generator through a reducer and has two levels of adjustable steam extraction. Usually, the first-level adjustment steam extraction is used for industrial steam, and the second-level adjustment steam extraction is used for residential heating. For the second-level adjustment steam extraction, in order to meet the steam flow and parameter requirements required for changes in residential heating loads, it is necessary to achieve it through the regulation of the rotating baffle. In order to reduce the lifting force of the turbine rotating baffle oil motor and reduce the front and rear pressure difference of the rotating ring, a balance cover ring is usually used on the rotating ring, which is easy to cause jamming due to high-speed rotation and thermal expansion of the turbine, posing a hidden danger to the safe operation of the turbine. In addition, there are also some turbine rotating baffle rotating ring limit failures, the flow area is completely closed, resulting in no cooling flow behind the rotating baffle, steam blockage and other problems, making the turbine unable to operate safely. In summary, a high-reliability rotating baffle is crucial for the safe operation of a high-speed double-extraction steam turbine. Summary of the invention

[0003] The present invention overcomes the shortcomings of the prior art and provides a double-extraction steam turbine unit rotary baffle. The rotary baffle is used for a high-speed double-extraction steam turbine unit and has a stable and reliable structure.

[0004] A double-extraction steam turbine unit rotating partition, comprising a rotating ring, a partition body and a steam seal body; the steam seal body is installed on the steam outlet side end surface of the partition body, the partition body is divided into an upper and lower semicircular body, the upper and lower semicircular bodies are detachably connected together, the rotating ring is divided into an upper and lower semicircular ring, the upper and lower semicircular rings are detachably connected together, the rotating ring is arranged in a circumferential groove at the front end of the partition body, and a plurality of partition steam channel windows are opened on the end surface of the partition body along the circumferential direction;

[0005] The rotating ring is an open rotating ring without a balance cover ring, and the outer circumferential surface of the rotating ring extends to be almost flush with the outer circumferential surface of the partition body; a plurality of guide blades are arranged circumferentially on the end surface of the rotating ring, which are divided into a large-head guide blade group and a small-head guide blade group with different pitches, the large-head guide blade group and the small-head guide blade group are alternately arranged, and the small-head guide blade group is centrally symmetrically distributed on both sides of the vertical center dividing plane, two adjacent guide blades are a rotating ring steam channel window, the rotating ring steam channel window corresponds one to one with the partition steam channel window, when the rotating partition is completely closed, the guide blades on the small-head guide blade group and the corresponding partition body steam channel window have reserved minimum flow area windows.

[0006] Compared with the prior art, the present invention has the following beneficial effects:

[0007] The rotating diaphragm structure of the present invention replaces the structure of the traditional rotating diaphragm with a balance cover ring. For the first time, an open rotating ring without a balance cover ring is used, which is convenient for the free rotation of the rotating ring, so that the double-extraction steam turbine unit can expand freely during operation. It solves the problem that the dynamic and static diaphragms are stuck when the traditional rotating diaphragm expands due to heat and the rotating ring cannot effectively cooperate with positioning and support, eliminates the phenomenon that the rotating ring is easily stuck due to too small a gap, and improves the stability of the unit operation. At the same time, two guide blades with different pitches are used in the steam flow channel on the rotating ring to replace the original guide blades of the same blade type, and the design is arranged alternately with different pitches, so as to realize the control of the steam flow rate and meet the requirement that there is enough cooling flow to cool the subsequent stages through the rotating diaphragm at the minimum opening. The present invention not only makes a lot of innovations in structure, is easy to control, and has more stable and reliable working performance, but also greatly improves the efficiency of the unit operation, and improves the reliability and safety of the high-speed double-extraction steam turbine unit. It also reduces energy consumption and realizes the rational application of energy.

[0008] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments: BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A front view of the rotating baffle of the present invention as viewed from the steam inlet direction;

[0010] Figure 2 is along Figure 1 Sectional view along line AA;

[0011] Figure 3 for Figure 1 The enlarged view at position I in FIG.

[0012] Figure 4 This is a diagram showing the relative positions of the open rotating ring and the diaphragm body without a balancing cover ring when the rotating diaphragm is fully opened;

[0013] Figure 5 This is the relative position diagram of the open rotating ring and the partition body without a balance cover when the rotating partition is fully opened. DETAILED DESCRIPTION

[0014] See also Figure 1 , Figure 2 , Figure 4 and Figure 5 As shown, a double-extraction steam turbine rotating partition of the present embodiment comprises a rotating ring 1, a partition body 2 and a steam seal body 3; the steam seal body 3 is installed on the steam outlet side end face of the partition body 2, the partition body 2 is divided into an upper and a lower semicircular body, the upper and lower semicircular bodies are detachably connected together, the rotating ring 1 is divided into an upper and a lower semicircular ring, the upper and lower semicircular rings are detachably connected together, the rotating ring 1 is arranged in a circumferential groove at the front end of the partition body 2, and a plurality of partition steam channel windows 2-1 are opened on the end face of the partition body 2 along the circumferential direction;

[0015] The rotating ring 1 is an open rotating ring without a balance cover ring, and the outer circumferential surface of the rotating ring 1 extends to be almost flush with the outer circumferential surface of the partition body 2; a plurality of guide blades are arranged circumferentially on the end surface of the rotating ring 1, which are divided into a large-head guide blade group and a small-head guide blade group with different pitches, and the small-head guide blade group is distributed on both sides of the center dividing surface, and the large-head guide blade group and the small-head guide blade group are arranged alternately, and two adjacent guide blades are a rotating ring steam duct window 1-1, and the rotating ring steam duct window 1-1 corresponds to the partition body steam duct window 2-1 one by one. When the rotating baffle is completely closed, the guide blades on the small-head guide blade group and the corresponding partition body steam duct window 2-1 leave a minimum flow area window.

[0016] This embodiment is applied to the rotating diaphragm of the steam turbine of a high-speed double-extraction unit. The oil motor is installed on the cylinder, and the connecting rod mechanism of the oil motor passes through the cylinder and is connected to the rotating ring 1. The open rotating ring without a balance cover ring is driven by the oil motor through the connecting rod mechanism. The diaphragm body is the base of the guide vanes and the rotating ring, and is the carrier of the steam channel. The open rotating ring without a balance cover ring has a steam channel window corresponding to the diaphragm body. The overlap between the rotating ring and the diaphragm body window is adjusted by rotating the open rotating ring without a balance cover ring, thereby changing the effective flow area of ​​the diaphragm body. Different steam extraction conditions of the unit are adjusted by the oil motor to drive the rotating ring to rotate a certain angle to adjust the flow area of ​​the rotating diaphragm steam flow channel, so as to adjust the steam flow rate to achieve the required extraction parameters and extraction volume. Two blade types with different pitches are used on the open rotating ring without a balance cover ring, which are divided into large-head guide vanes and small-head guide vanes, such as Figure 4 and Figure 5 As shown, the cross-sectional widths of the sealing baffle body steam duct windows 2-1 of the large-head guide vanes and the small-head guide vanes are different, and the two sides of the large-head guide vanes and the small-head guide vanes corresponding to the rotating ring steam duct windows are arc-shaped, with a circular arc transition between the two sides. Optionally, the guide vanes are welded to the rotating ring. The multiple guide vanes of the small-head guide vane group 1-3 are evenly distributed, and the multiple guide vanes of the large-head guide vane group 1-2 are evenly distributed, so that when the rotating baffle is in the fully closed state, the guide vanes on the small-head guide vane group 1-3 and the corresponding baffle body steam duct windows 2-1 have a minimum flow area window, and there is still enough cooling flow. The corresponding relationship between the angle of rotation of the rotating baffle and the pressure and flow is given through steam distribution calculation to meet the steam flow and parameters required for changes in the heating load of residents.

[0017] Optionally, a boss 2-1 extending outward is provided on the steam inlet side end face of the partition body 2, and the boss 2-1 is in contact with the rotating ring 1. The boss is in direct contact with the rotating ring, which reduces the friction area and eliminates the jamming phenomenon.

[0018] As an example: Figure 1As shown, the large-head guide vane group 1-2 is divided into two equal groups, distributed in the upper and lower parts, with a total of 16 large-head guide vanes in the two groups, 8 of which are evenly distributed in the upper and lower parts, and the small-head guide vane group 1-3 is divided into two equal groups, with 10 evenly distributed in each group, arranged on the upper and lower sides of the horizontal center plane, with a total of 20 small-head guide vanes in the two groups. It is achieved that when the rotating partition is in the fully closed state, the effective flow area corresponding to the large-head blades is zero, and the effective flow area corresponding to the small-head blades is the smallest. The guide vanes on the small-head guide vane group and the corresponding partition body steam channel window 2-1 have a minimum flow area window, and there is still enough cooling flow to meet the steam flow and parameters required for changes in the heating load of residents.

[0019] As an example: Figure 2 As shown, a groove is formed at the bottom of the steam seal body 3, in which a steam seal sheet 4 is fixedly installed. A gasket 5 is also fixedly installed in the groove to abut against the steam seal sheet 4. The steam seal body 3 is fixedly connected to the partition body 2 by bolts 6.

[0020] It should be noted that: Figure 3 In the embodiment, a hole c needs to be drilled and reamed on the partition body 2 together with the rotating ring 1. This hole is required for installing the transmission lever of the oil motor. The implementation of this embodiment is connected to the rotating ring 1 through the connecting rod mechanism of the oil motor, and the rotating ring 1 is driven by the oil motor to rotate. The rotating partition is composed of a large-head blade and a small-head blade. Figure 1 The partition body 2 is the base of the guide vanes and the rotating ring, and is the carrier of the steam channel. The steam channel window corresponding to the guide vanes in the partition body 2 is opened on the rotating ring 1. By adjusting the overlap between the rotating and partition body 2 steam channel windows, the effective flow area of ​​the rotating partition can be changed. When the rotating ring 1 rotates to the reaming hole b, the blade rotation position at this time is as shown in FIG. Figure 4 As shown in the figure, it means that the rotating partition is in the fully open state, and the effective flow area is the largest at this time. When the rotating ring 1 rotates to the reaming hole a, the blade rotation position is as follows Figure 5 As shown, it means that the rotating partition is in a fully closed state. Due to the use of large and small head guide blade groups, the effective flow area corresponding to the guide blades of the large head group is zero at this time, and the guide blades 1-3 of the small head group and the corresponding partition body steam channel window 2-1 leave a minimum flow area window. The effective flow area of ​​the window corresponding to the guide blades of the small head group is the smallest, so a small amount of steam will work. The design on the rotating ring 1 uses two blade types with different pitches to ensure sufficient cooling flow at the minimum opening. The rotating ring 1 controls the high-temperature steam flow by rotating between the drilled holes a and b to change the effective flow area of ​​the steam flow channel to meet the user's winter heating needs. When the temperature drops in winter, the opening of the rotating partition can be increased according to the heating demand to increase the amount of heating steam. When the temperature rises in summer, the opening of the rotating partition can be appropriately reduced, which can not only meet the optimal temperature required for the user's daily life, but also meet the requirements of energy conservation and emission reduction.

[0021] The present invention has been disclosed as above with preferred implementation cases, but it is not used to limit the present invention. Any technician familiar with the profession can make slight changes or modifications to equivalent implementation cases with equivalent changes by using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present invention, which still fall within the scope of the technical solution of the present invention.

Claims

1. A double-extraction steam turbine rotating diaphragm, comprising a rotating ring (1), a diaphragm body (2) and a steam seal body (3); the steam seal body (3) is installed on the steam outlet side end surface of the diaphragm body (2); the diaphragm body (2) is divided into an upper and a lower semicircular body, the upper and lower semicircular bodies are detachably connected together, the rotating ring (1) is divided into an upper and a lower semicircular ring, the upper and lower semicircular rings are detachably connected together, the rotating ring (1) is arranged in a circumferential groove at the front end of the diaphragm body (2), and a plurality of diaphragm steam channel windows (2-1) are opened on the end surface of the diaphragm body (2) along the circumferential direction; Features: The rotating ring (1) is an open rotating ring without a balancing cover ring, and the outer circumferential surface of the rotating ring (1) extends to be nearly flush with the outer circumferential surface of the partition body (2); a plurality of guide blades are arranged along the circumferential direction on the end surface of the rotating ring (1), and the guide blades are welded to the rotating ring (1). The plurality of guide blades are divided into a large-head guide blade group (1-2) and a small-head guide blade group (1-3) with different pitches, and the small-head guide blade group (1-3) is centrally symmetrically distributed on both sides of a vertical center plane, and the large-head guide blade group and the small-head guide blade group are alternately arranged. Two adjacent guide blades form a rotating ring steam duct window (1-1), and the rotating ring steam duct window (1-1) corresponds to the partition body steam duct window (2-1) one by one. When the rotating partition is completely closed, the guide blades on the small-head guide blade group (1-3) and the corresponding partition body steam duct window (2-1) leave a minimum flow area window.

2. The double extraction steam turbine unit rotating baffle according to claim 1, characterized in that: A boss (2-2) extending outward is provided on the steam inlet side end surface of the partition body (2), and the boss (2-2) is in contact with the rotating ring (1).

3. A double extraction steam turbine unit rotating baffle according to claim 1 or 2, characterized in that: The large-head guide blade group (1-2) is divided into two equal groups, distributed at the upper part and the lower part of the rotating ring (1), and the two groups have a total of 16 large-head guide blades; the small-head guide blade group (1-3) is divided into two equal groups, and the two groups have a total of 20 small-head guide blades.

4. The double extraction steam turbine unit rotating baffle according to claim 3, characterized in that: A groove is formed at the lower part of the steam seal body (3), and a steam seal sheet (4) is fixedly installed in the groove.

5. The double extraction steam turbine unit rotating baffle according to claim 4, characterized in that: A gasket (5) is also fixed in the groove and abuts against the steam sealing plate (4).

6. The double extraction steam turbine rotating baffle according to claim 5, characterized in that: The steam seal body (3) is fixedly connected to the partition body (2) via bolts (6).

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