阅读说明：本技术 一种水轮机双支撑圆形顶盖结构 (Double-support circular top cover structure of water turbine ) 是由 覃大清 赵越 刘永新 许义群 郭娜 张春 宋昱元 柏勇 王焕茂 吴喜东 许彬 于 2021-08-12 设计创作，主要内容包括：本发明公开一种水轮机双支撑圆形顶盖结构,由座环、顶盖、螺母、顶盖连接螺栓、密封条、转轮、水导轴承、主轴、蜗壳组成；座环位于蜗壳内部,顶盖通过顶盖连接螺栓、螺母与座环固定连接,水导轴承固定在顶盖内部,主轴下端连接转轮,另一端连接水导轴承。圆形顶盖结构填补顶盖与座环间的间隙、并可在顶盖装配过程中起到导向作用；实现机组径向力的双支撑方式,改善顶盖连接螺栓受力状态,提高机组安全性,延长顶盖连接螺栓使用寿命；尤其在顶盖连接螺栓松动或失效时,减少压力水从顶盖与座环间的溢出量,提高电站安全运行系数。(The invention discloses a double-support circular top cover structure of a water turbine, which consists of a seat ring, a top cover, a nut, a top cover connecting bolt, a sealing strip, a rotating wheel, a water guide bearing, a main shaft and a volute; the seat ring is positioned inside the volute, the top cover is fixedly connected with the seat ring through a top cover connecting bolt and a nut, the water guide bearing is fixed inside the top cover, the lower end of the main shaft is connected with the rotating wheel, and the other end of the main shaft is connected with the water guide bearing. The circular top cover structure fills the gap between the top cover and the seat ring and can play a role in guiding in the process of assembling the top cover; the double-support mode of the radial force of the unit is realized, the stress state of the top cover connecting bolt is improved, the safety of the unit is improved, and the service life of the top cover connecting bolt is prolonged; especially when top cap connecting bolt is not hard up or became invalid, reduce the overflow volume of pressurized water from between top cap and the seat ring, improve the power station safe operation coefficient.)

1. The utility model provides a circular roof structure of hydraulic turbine dual bracing which characterized in that: the device comprises a seat ring (1), a top cover (2), a nut (3), a top cover connecting bolt (4), a sealing strip (5), a rotating wheel (6), a water guide bearing (7), a main shaft (8) and a volute (9); the seat ring (1) is located inside the volute (9), the top cover (2) is fixedly connected with the seat ring (1) through a top cover connecting bolt (4) and a nut (3), the water guide bearing (7) is fixed inside the top cover (2), the lower end of the main shaft (8) is connected with the rotating wheel (6), and the other end of the main shaft is connected with the water guide bearing (7).

2. The double-support circular top cover structure of the water turbine as claimed in claim 1, wherein: the cylindrical surface (12) of the top cover (2) is provided with a ring structure (11) with a semicircular cross section.

3. The double-support circular top cover structure of the water turbine as claimed in claim 1, wherein: the upper semicircular annular structure (11) of the cylindrical surface (12) of the top cover (2) is tangent to the lower end surface of the top cover (2).

4. The double-support circular top cover structure of the water turbine as claimed in claim 1, wherein: the difference between the sum of the radius of the semicircular annular structure (11) on the cylindrical surface (12) of the top cover (2) and the radius of the inner cylindrical surface (13) of the seat ring (1) is 10-20 mm.

Technical Field

The invention relates to a double-support circular top cover structure of a water turbine, and belongs to the field of fluid machinery.

Background

The water turbine is used as a prime motor of the hydroelectric generating set and is used for converting the mechanical energy of water into rotary kinetic energy which can be used by a generator. Because the water turbine can operate under different water heads and different working conditions, the unit has a large operating range with load, is frequently started and stopped, and can often operate under a non-optimal working condition, the top cover is acted by the water pressure from the flow channel, and the water pressure is transmitted to the top cover connecting bolt by the top cover, so that the top cover connecting bolt bears alternating tensile stress. Meanwhile, the rotation of the main shaft can generate alternating radial force with a certain period in the rotating process of the rotating wheel, and the radial force is finally transmitted to the top cover connecting bolt through the water guide bearing and the top cover, so that the top cover connecting bolt is subjected to an alternating torque effect. Under the effect of these two power, the risk that top cap connecting bolt became invalid increases, and top cap connecting bolt's life reduces. Therefore, the hydraulic turbine top cover structure is urgently needed to optimize the stress state of the top cover connecting bolts, the phenomenon that the fatigue looseness of the top cover connecting bolts causes unit vibration aggravation, the safe operation of a power station is influenced, and even the personal safety of power station workers is endangered is avoided.

Fig. 1 shows a conventional top cover connection structure of a hydroelectric generating set, which comprises a rotating wheel, a main shaft, a water guide bearing, a top cover, a seat ring, a volute, a top cover connection bolt and a nut. The seat ring is positioned in the volute and plays a supporting role for the whole unit, and in practical engineering application, due to the fact that the sizes of the top cover and the seat ring are large, enough radial gaps are usually reserved between the top cover and the seat ring for guaranteeing smooth assembly. The top cover is fixedly connected with the seat ring through a top cover connecting bolt and a nut, the water guide bearing is fixed inside the top cover, one end of the main shaft is connected with the rotating wheel, and the other end of the main shaft is connected with the water guide bearing. When the water turbine works, water flow enters from the volute, flows through the seat ring and the top cover and then enters the rotating wheel, and pushes the rotating wheel to rotate to do work; the radial force borne by the rotating wheel can be transmitted to the water guide bearing and the top cover through the main shaft and finally transmitted to the top cover connecting bolt, so that the top cover connecting bolt bears an alternating radial force. In addition, the sealing strip is installed between top cap flange lower extreme face and seat ring up end for the interior high pressure water of sealed runner, and when top cap connecting bolt becomes flexible or became invalid the back sealing strip compact size reduces, and the high pressure water can flow into sealed face and then spill over through the radial clearance between top cap, seat ring, increases the unit operation risk.

Disclosure of Invention

In view of the above, the present invention discloses a double-support circular top cover structure of a water turbine, which can fill a gap between a top cover and a seat ring, and can play a role in guiding during the assembly of the top cover, thereby realizing a radial force double-support mode of the turbine, improving the stress state of a top cover connecting bolt, and improving the safety of the turbine. The technical scheme of the invention is described as follows: a double-support circular top cover structure of a water turbine consists of a seat ring, a top cover, a nut, a top cover connecting bolt, a sealing strip, a rotating wheel, a water guide bearing, a main shaft and a volute; the seat ring is positioned inside the volute, the top cover is fixedly connected with the seat ring through a top cover connecting bolt and a nut, the water guide bearing is fixed inside the top cover, the lower end of the main shaft is connected with the rotating wheel, and the other end of the main shaft is connected with the water guide bearing.

In the above-mentioned double-support circular top cover structure of the water turbine, the cylindrical surface of the top cover has an annular structure with a semicircular section.

In the double-support circular top cover structure of the water turbine, the semicircular annular structure on the cylindrical surface of the top cover is tangent to the lower end surface of the top cover.

In the double-support circular top cover structure of the water turbine, the difference between the sum of the radius of the semicircular section on the cylindrical surface of the top cover and the radius of the inner cylindrical surface of the seat ring is 10-20 mm.

The beneficial technical effects of the invention are as follows:

1. the radial force generated by the unit during operation is jointly borne by the top cover connecting bolt and the semicircular annular structure on the cylindrical surface of the top cover; the original single fulcrum stress is changed into the existing double fulcrum stress, the stress state of the top cover connecting bolt is improved, the safety of the unit is improved, and the service life of the top cover connecting bolt is prolonged.

2. When the top cover connecting bolt is loosened or fails, the gap between the top cover and the seat ring is filled by the semicircular annular structure on the cylindrical surface of the top cover, so that the overflowing area is reduced, the overflowing amount of pressure water between the top cover and the seat ring is further reduced, and the safe operation coefficient of the power station is improved.

Drawings

FIG. 1 is a diagram of a conventional roof connection structure of a hydroelectric generating set;

FIG. 2 is a top cover connection block diagram of the present invention;

FIG. 3 is a top cover construction of the present invention;

fig. 4 is a block diagram of a hydroelectric generating set seat ring.

The notation in the figure is: 1-a seat ring; 2-a top cover; 3-a nut; 4-top cover connecting bolts; 5-sealing strips; 6-rotating wheel; 7-water guide bearing; 8-a main shaft; 9-a volute; 11-semi-circular ring structure on the cylindrical surface 12 of the top cover 2; 12-cylindrical surface of the top 2; 13-the inner cylindrical surface of the seat ring 1.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

As shown in fig. 2, a double-support circular top cover structure of a water turbine comprises a seat ring 1, a top cover 2, a nut 3, a top cover connecting bolt 4, a sealing strip 5, a runner 6, a water guide bearing 7, a main shaft 8 and a volute 9. The seat ring 1 is positioned in the volute 9 and plays a supporting role for the whole unit, the top cover 2 is fixedly connected with the seat ring 1 through the top cover connecting bolt 4 and the nut 3, the water guide bearing 7 is fixed in the top cover 2, the lower end of the main shaft 8 is connected with the rotating wheel 6, and the other end of the main shaft is connected with the water guide bearing 7.

As shown in figure 3, the cylindrical surface 12 of the top cover 2 is provided with a semicircular annular structure 11 with a cross section, and the lower part of the semicircular annular structure 11 is tangent to the lower end surface of the top cover 2.

The difference between the sum of the radius of the cylindrical surface 12 of the top cover 2 and the radius of the semicircular annular structure 11 and the radius of the inner cylindrical surface 13 of the seat ring 1 as shown in fig. 3 and 4 is 10 mm to 20 mm, namely, the following relation is satisfied:

10≤R2-r-R1≤20

in the formula: r is the radius of the semicircular annular structure 11 in millimeters;

r1 is the radius in mm of the cylindrical surface 12 of the top 2;

r2 is the radius in millimeters of the inner cylindrical surface 13 of the seating ring 1.

The working principle is as follows: the double-support circular top cover structure of the water turbine can share the radial force generated during the operation of a unit with the top cover connecting bolt, and changes the stress of a single pivot into the stress of double pivots, so that the stress state of the top cover connecting bolt is improved, the safety of the unit is improved, and the service life of the top cover connecting bolt is prolonged. In the top cover assembling process, the semi-circular annular structure on the top cover cylindrical surface can play a role in guiding, so that the top cover can be assembled conveniently. When the top cover falls into the seat ring, the coaxiality of the top cover and the seat ring needs to be adjusted, and the central position of the top cover is adjusted by taking the semicircular annular structure on the cylindrical surface of the top cover as a fulcrum, so that the top cover is coaxially connected with the seat ring. When the top cover connecting bolt is loosened or fails, the gap between the top cover and the seat ring is filled up due to the semicircular annular structure on the cylindrical surface of the top cover, so that the overflow amount of pressure water from the top cover to the seat ring is reduced, and the safe operation coefficient of the power station is improved.

Finally, the scope of protection of the invention is not limited to the embodiments described above. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. It is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.