阅读说明：本技术 一种基于布莱登可调结构的新型微间隙汽封 (Novel micro-gap steam seal based on adjustable Brayton structure ) 是由 不公告发明人 于 2020-08-12 设计创作，主要内容包括：本发明公开了一种基于布莱登可调结构的新型微间隙汽封,属于汽机密封件技术领域；它包括八段汽封弧块和微间隙汽封齿；在汽封弧块的端部分别装有弹簧,且在汽封弧块的进汽侧加工有进汽槽道,微间隙汽封齿使用0Cr15Mo(或优于0Cr15Mo进口材质)材料制成；微间隙汽封齿包括高齿和低齿,且低齿为斜侧齿结构；本发明有效解决了当前在使用布莱登可调式汽封的过程中容易发生碰摩从而导致转子轴、围带的损伤、负荷压差过低无法关闭等问题。(The invention discloses a novel microgap steam seal based on a Brayton adjustable structure, belonging to the technical field of steam turbine sealing parts; the steam seal comprises eight sections of steam seal arc blocks and micro-gap steam seal teeth; the end parts of the steam seal arc blocks are respectively provided with a spring, a steam inlet channel is processed at the steam inlet side of the steam seal arc blocks, and the micro-gap steam seal teeth are made of 0Cr15Mo (or a material which is superior to 0Cr15 Mo) material; the micro-gap steam seal teeth comprise high teeth and low teeth, and the low teeth are of oblique side tooth structures; the invention effectively solves the problems that the rotor shaft and the shroud ring are damaged and the load differential pressure is too low to close due to easy rubbing in the process of using the Braiden adjustable steam seal at present.)

1. A novel microgap steam seal based on a Brayton adjustable structure comprises eight sections of steam seal arc blocks (1) and microgap steam seal teeth (2); the method is characterized in that: the end parts of the steam seal arc blocks (1) are respectively provided with a spring (3), a steam inlet channel (4) is processed at the steam inlet side of the steam seal arc blocks (1), and the micro-gap steam seal teeth (2) are made of 0Cr15Mo material; the micro-gap steam seal tooth (2) comprises a high tooth (2A) and a low tooth (2B), and the low tooth (2B) is of an oblique side tooth structure.

2. The novel microgap steam seal based on the adjustable brayton structure of claim 1, characterized in that: the steam seal arc block (1) and the micro-gap steam seal tooth (2) are of an integral steam seal structure which is formed by integrally forming the same 0Cr15Mo material by using a processing method.

3. The novel microgap steam seal based on the adjustable brayton structure of claim 1, characterized in that: the steam inlet channel (4) is obtained by milling.

4. The novel microgap steam seal based on the adjustable brayton structure of claim 1, characterized in that: the micro-gap gland sealing teeth (2) are subjected to surface treatment.

5. The novel microgap steam seal based on the adjustable brayton structure of claim 1, characterized in that: the inclination angle between two low teeth on each group of low teeth (2B) is15°~25°。

6. The novel microgap steam seal based on the adjustable brayton structure of claim 1, characterized in that: the material of the spring (3) is the same as that of the high-medium pressure Braille adjustable steam seal spring, and on different steam seals, the parameters of the spring (3) are related according to the pressure and the weight of the steam seal and the parameters of the actual operation of the steam seal.

Technical Field

The invention relates to the technical field of steam turbine sealing elements, in particular to a novel micro-gap steam seal based on a Brayton adjustable structure.

Background

The steam seal is a device which is arranged between the dynamic part and the static part of the steam turbine and reduces or prevents the leakage of steam and the leakage of air at the vacuum side; with the development of steam turbine technology, the requirements for steam sealing are gradually increased; after the adjustable blandon vapor seal is introduced into China, the adjustable blandon vapor seal is popularized and applied to important occasions such as various generator sets and the like due to good safety, economy and durability; however, due to the technical defects of the spring on the Brayton structure steam seal, at the initial load stage faced by the starting process of the unit, the steam seal is in a full-open position under the action of the spring, the gap is at the maximum value at the moment, the steam leakage amount of the steam seal is maximum, the rotor is heated quickly, the cylinder cannot be heated, the shaft string is easy to appear, and the radial rubbing is easy to occur; meanwhile, in the normal starting and stopping process, the damage of a rotor shaft and a shroud band caused by dynamic and static collision and friction is easily caused as other conventional steam seals are the same; this is a major problem currently faced when using gland seals.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the utility model provides a novel microgap vapor seal based on adjustable structure of blandon to thereby it rubs easily to take place to bump the damage that leads to rotor shaft, shroud ring, load differential pressure hang down unable closed scheduling problem at present in the in-process that uses adjustable vapor seal of blandon.

In order to solve the problems, the invention provides the following technical scheme:

a novel microgap steam seal based on a Brayton adjustable structure comprises eight sections of steam seal arc blocks and microgap steam seal teeth; the end parts of the steam seal arc blocks are respectively provided with a spring, a steam inlet channel is processed at the steam inlet side of the steam seal arc blocks, and the micro-gap steam seal teeth are made of 0Cr15Mo material; the microgap gland sealing teeth comprise high teeth and low teeth, and the low teeth are in a skewed side tooth structure.

Preferably, the steam seal arc block and the micro-gap steam seal tooth are of an integral steam seal structure which is formed by integrally forming the same 0Cr15Mo material.

Preferably, the steam inlet channel is obtained by milling.

Preferably, the microgap gland teeth are surface treated.

Preferably, the low teeth have a tooth inclination angle of15°～25°

Preferably, the material of the spring is the same as that of the high-medium pressure Braille adjustable steam seal spring, and on different steam seals, the parameters of the spring are related according to the pressure and the weight of the steam seal and the parameters of the actual operation of the steam seal.

The invention has the beneficial effects that:

the invention improves the structure of the conventional Brabender vapor seal, and the advantages of the improved product are shown in the following aspects:

1. as an improved structure of the Brayton adjustable steam seal, the device also inherits the advantages of the Brayton steam seal, namely, a steam seal body can be automatically opened and closed in the starting and stopping processes of a unit through a spring, and simultaneously, the radial clearance between the steam seal and a rotor is always kept in a small range in the normal operation of the unit, namely, the lower limit of a design value is met;

2. in the concrete improvement measure, the material of the microgap steam seal tooth is changed into ferrite material of 0Cr15Mo (the performance of the ferrite material is equal to or better than that of 0Cr15Mo, and other materials with the performance of 0Cr15Mo are also available), and because the ferrite material has the advantage of difficult hardening, the direct contact friction between the steam seal tooth and a rotor shaft and a shroud band can be allowed, and the lower hardness value when leaving the factory is kept, thereby protecting the rotor, reducing the friction time, reducing the probability of rotor vibration or deformation, further improving the operation safety of a machine set, and preventing the hardened steam seal tooth from damaging the rotor and the shroud band

3. Based on the use of the Braiden spring and the improvement of the steam seal tooth material, the use clearance of the steam seal is reduced from 0.35-0.5mm of the conventional Braiden steam seal to the specification of 0.15 +/-0.05 mm, the steam seal clearance is an important index of the production efficiency of the reaction unit, according to the experience, the steam seal clearance of each level of partition plate of the high-pressure part of the unit is increased by 0.1mm, the level efficiency is reduced by 0.4-0.6%, so that the smaller steam seal clearance provides better sealing performance, the rotation speed of a steam turbine rotor is improved, and the economic benefit of the steam turbine unit is greatly improved;

4. in the improvement measure, low teeth on the original comb-tooth type steam seal are changed into an oblique side tooth form, and the flow resistance of the steam seal in the working process is increased and the steam leakage is reduced by redesigning the tooth space and the tooth inclination angle; the sealing performance of the steam seal is improved;

5. the invention further improves the conventional assembled steam seal tooth and the steam seal body into an integral steam seal structure, effectively reduces the peak stress of the steam seal tooth, eliminates the high-cycle fatigue stress, and improves the natural frequency of the steam seal tooth, thereby reducing the tooth fracture phenomenon possibly occurring in the steam seal operation process and realizing the long-term and reliable operation of the steam seal;

6. the Braiden steam seal before improvement can not realize the complete closure of the steam seal when the unit load does not reach 100%, and after improvement, due to the optimization of the steam seal structure and the closure sequence, all the steam seals can be ensured to be completely closed even when the unit load is only 25-30%, so that the use problem of the Braiden steam seal in the low-load operation state of the steam turbine at present is well solved;

7. the invention has no special processing requirement on the steam seal body and the clapboard groove, although the invention is based on the improvement of the Brayton steam seal, the price of the invention has certain advantages compared with the Brayton steam seal introduced into China in terms of manufacturing cost.

Drawings

FIG. 1 is a schematic structural view of the present invention;

description of reference numerals: 1. the steam seal device comprises a steam seal arc block, 2 parts of micro-gap steam seal teeth, 2 parts of high teeth, 2 parts of low teeth, 3 parts of springs, 4 parts of air inlet channels.

Detailed Description

The invention will be further described with reference to the following drawings and specific embodiments: