CN1088144C

CN1088144C - Steam filter for steam turbine

Info

Publication number: CN1088144C
Application number: CN96120655A
Authority: CN
Inventors: 罗纳德·E·布兰登; 戴维·E·布兰登
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-11-27
Filing date: 1996-11-01
Publication date: 2002-07-24
Anticipated expiration: 2016-11-01
Also published as: CN1156212A

Abstract

In a steam turbine inlet which includes an annular steam strainer stationarily positioned therein for stopping the passage into the turbine of large metal particles in the steam, the improvement in the strainer which comprises a plurality of spaced through holes in a major portion of the strainer circumference, the through holes being of differing diameters, with holes of like diameter being positioned in longitudinally-extending, circumferential zones, holes of the largest diameter being disposed in zones where metal particles are least likely to enter the holes, holes of smaller diameter being disposed in zones where metal particles are most likely to enter the holes, and a longitudinally-extending, circumferential zone in the strainer without holes where the particles velocity and direction of movement would be damaging to any holes located in such a zone, the through holes each having an entrance end on the outer periphery of the strainer, an exit end on the inner periphery of the strainer, and an interior portion disposed between the entrance end and exit end, the exit end having a larger diameter than the interior portion to reversably slow steam velocity and decrease steam pressure drop.

Description

Steam filter for steam turbine

Technical field

The application is that the sequence number submitted on November 25th, 1994 is the part continuation application of 08/344862 pending application.

The big particulate matter that the present invention relates to steam turbine and be used for stoping steam to carry enters the device of steam turbine.

Background technique

All steam turbine all have vapor filter, are used for catching the particulate matter that steam that boiler supplies with carries, and prevent that it from entering steam turbine, in order to avoid cause the badly damaged of steam turbine.

Have the vapor filter of one of two types of common uses of steam turbine now.

First type is a cylinder that has some macropores, and these macropores are arranged so that the filter screen that has aperture is around one week of cylinder layout.Such filter can filter out in the steam particle greater than about 1/8 inch size.This type systematic can also temporarily install a thinner filter screen additional, produces short-term use under the serious situation of particulate matter in known boilers.The little defective that this class filter occurs is that filter screen itself will lose efficacy with the passing of operation and service time, thereby causes the inner serious damage of steam turbine.Simultaneously steam by must through filter screen and during the hole of filter, the pressure that has increased steam falls.

Second type filter is a simple cylinder, has many apertures.These holes allow steam by but stop the particle bigger to pass through than the hole.The selection in hole is different different because of the design of steam turbine.About 1/4 inch hole is selected in the design that has for use, and other then select about 3/32 inch hole for use.The mouth of leading of square vertical cut formula is adopted in the hole of this class filter, and like this, flow coefficient is relatively little, thereby causes bigger admission pressure drop.These holes are easy to be damaged by the particle of high-speed motion, and then reduce the valid circulation area of steam flow and increase unnecessary pressure drop.

The objective of the invention is to eliminate the filter screen Problem of Failure that in above-mentioned first type filter, occurs; Further purpose is the overall dimensions that reduces by the filter particle; Further purpose is the work pressure drop that all produces when reducing steam through any filter.In addition, simplify the use and maintenance of filter.

In order to realize the foregoing invention purpose, the invention provides a kind of vapor filter, be loaded in the system for admitting steam into turbine regularly, big metallic enters steam turbine in the steam in order to stop, it is characterized in that: the most of area arrangements at the filter circumference has a plurality of through holes at regular intervals, the diameter of through hole has nothing in common with each other, the hole of similar diameter is positioned at the circumferential area of same longitudinal extension, the hole of maximum diameter is arranged in the zone that metallic seldom may enter, and the hole of minor diameter is arranged in the zone that the metallic most probable enters; And a circumferential area that does not have the longitudinal extension in hole is arranged in the filter; Each through hole all has one to import end Y at the filter cylinder outer wall, then has one to derive end at the filter cylinder inner wall, and intermediate portion is arranged with deriving between the end importing end, and it is bigger than intermediate portion to derive the diameter of holding.

Description of drawings

Fig. 1 implements the partial cross section view that is installed in a filter in the steam turbine stop valve housing of the present invention;

Fig. 2 is the stereogram of Fig. 1 middle filtrator;

Fig. 3 shows Fig. 2 middle filtrator planimetric map that is non-coiling or deployed condition;

Fig. 4 is the part enlarged view that is horizontally through the cross section of cutting open that Fig. 2 middle filtrator got;

Fig. 5 is that the part that the filter of the improvement form that is horizontally through is got is amplified the cross-sectional view of cutting open;

Fig. 6 is the partial cross section view that is installed on the improved filter in the steam turbine stop valve housing among Fig. 5; And

Fig. 7 is the stereogram of the improved filter among Fig. 5, has for clarity sake removed filter screen.

Embodiment is described

Fig. 1 is the partial cross section view of a steam turbine stop valve housing 11.Steam enters valve chest by admission passage 14, and arrow S represents the steam flow direction.

What comprise in the valve chest 11 is a columnar vapor filter 13, has promptly embodied preferred form of the present invention.The hole that vapor filter 13 has multirow to be arranged in parallel across a certain distance mutually represents with 17 that usually these hole along continuous straight runs extend through the filter barrel.

All steam all must be by the hole 17 on the filter barrel, and the purpose that the hole is set is to stop the big metal granule (not shown) from boiler to enter steam turbine (not shown).

After steam is by the hole 17 on the filter 13, flow through valve discharge tube 12, enter steam turbine (not shown) then.The upper end of filter contacts with the lid of valve chest, and the lower end contacts with the internal surface of valve chest, the contact preventing of this two ends metal and metal the steam flow bleeder.

In valve chest 11, an annular pass 26 is around filter 13.This passage passes through between valve chest and filter by steam flow, makes steam by hole all on the filter 17.By position in annular pass 26 one boss 27 is set, forms a partial occlusion, the shuttling movement of steam or particle is cut to bone over against admission passage 14.

As shown in Figure 4, all there is a collar extension in each hole 17 or imports end X on the outer wall of filter cylinder, and an internal orifice is arranged on the inwall of filter cylinder or derive end Y, is intermediate portion W importing end X and deriving between the end Y.

The diameter in each hole 17 from import end X to intermediate portion W along the position at about center of length the time, be constant substantially, and to the inner in hole one uniform tapering Z arranged by this central position, provide the inner or derivation of a bell shape to hold Y.Therefore it is bigger than intermediate portion W to derive end aperture, Y place.

The tapering of end Y is Z-shaped to have become a radial passage because guiding derives, this structure decrease in hole 17 pressure drop that produces during by filter 13 of steam.

The purpose of radial passage is that the derivation end in the hole oppositely slows down steam flow rate to improve vapor pressure.Reduced in the hole by 17 pressure drop like this, also reduced the pressure drop that steam flow is turned to 90 degree and cause, steam flow is directed to steam turbine stop valve (not shown) like this, thereby has improved the turbine work performance.

The tapering in hole 17 and angle be can change to adapt to different application needs.Someone advises that the half-angle of tapering is 3.5 degree, and awl length should be got the circulation area twice that is enough to increase the hole.

Fig. 2 is the stereogram of a cylindrical shape vapor filter 13.Hole 17 is distributed on most of zone of filter barrel circumference.Yet, the part 16 of impacting for the high speed steam flow that is subjected on the filter entering, cloth hole not in the circumferential area of longitudinal extension by steam inlet passage 14.A-a ' expression is used in this zone in a circumferential direction.

In the circumferential area b-d of longitudinal extension at regular intervals, the hole 17b-17d of different-diameter is set.On the filter circumference, in circumferential area the b '-d ' of remaining longitudinal extension at regular intervals, hole the 17b '-17d ' of different-diameter is set.

In regional b that lays respectively at part 16 and regional a and a ' both sides and b ', the aperture of

hole

17b and 17b ' is all relatively large, is 1/4 inch the order of magnitude.

At the regional c and the c ' that lay respectively at regional b and b ' both sides,

hole

17c and 17c ' are slightly little, are 1/8 inch in moderate aperture.

At the regional d and the d ' that lay respectively at regional c and c ' both sides, the aperture minimum of

hole

17d and 17d ' is 3/22 inch the order of magnitude.

Be illustrated in Fig. 3 from the variation relation of each regional a-d and a '-d ', wherein, the wall of filter has been unfolded.

Arrange that based on this subregion relatively

large hole

17b and 17b ' are used in regional b and b ', particle almost has no chance to enter this district.And

aperture

17d and 17d ' are used in regional d and this district's particle of d ' is active, easily hand-hole.The particle of adjacent domain b and b ' through the annular pass 26 at the enterprising hand-hole 17 of the direction of the axis that is parallel to hole 17 usually.The particle of adjacent domain d and d ' jumps and is stirred to move in random direction by steam flow, and therefore, the easier hole 17 that enters in these zones of these particles is especially when these holes are big.

A kind of improved form of filter 113 of the present invention is implemented in Fig. 5-7 explanation.

In this embodiment, a thin filter screen 122 is installed in filter 113 outsides, its inlet is in 123 places welding, and/or add rivet or gong nail (not shown); And filter 113 replaces the filter 13 of valve chest 11 central authorities.

The filter 113 that has fie screen 112 under maximum possible is situation from the particle of boiler, can temporarily use.Crossette 128 among the figure is in order to the protection fie screen.

The filter 13 in Fig. 1-4, most of zone of the barrel circumference of filter 113 is cloth porose 117 all.And circumferential section that extends longitudinally that bears that the high speed steam flow that entered by admission passage 14 impacts at filter or zone 116 cloth hole not.

On filter 113, have the hole 117b-117d and hole the 117b '-117d ' of different-diameter, they penetrate the remaining part setting of filter wall at longitudinal extension direction circumferential area with a determining deviation.

As what Fig. 5 clearly illustrated, hole 117 is circular, as outer entry end X ', also is circular in the profile of 124 place's filter walls, in order to reduce steam drop and because of the damage of particle hits to the hole.

In addition, all there is an inner or derivation end Y ' in each hole 117 on the filter cylinder inner wall, and at the intermediate portion W ' that imports between end X ' and the derivation end Y '.

The position of the diameter in each hole 117 from the importing end X ' of circle to the approximate center of the length of intermediate portion W ' is constant substantially.Then there is the tapering Z that increases gradually the approximate center position to the inner in hole thus, to form the inner of a bell shape or to derive end Y '.Therefore locate greatly than intermediate portion W ' in the aperture that derivation end Y ' locates.

The same with the embodiment among Fig. 1-4, this structure decrease in hole 117 pressure drop that produces when the filter 113 of steam.Guide to the tapering Z ' that derives end Y ' and form a radial passage, purpose is the steam flow rate that oppositely slows down of the derivation end in the hole, improves vapor pressure.Reduce in the hole by 117 pressure drops that produce simultaneously and for the required pressure drop that steam flow is turned to 90 degree cause of the stop valve (not shown) of steam turbine that steam flow is led.Thereby improved the turbine work performance.

Need point out that vapor filter of the present invention is applicable to high-pressure turbine, also be applicable to the intake system of heating type steam turbine again.

Claims

1, a kind of vapor filter is loaded in the system for admitting steam into turbine regularly, and big metallic enters steam turbine in the steam in order to stop, and it is characterized in that:

Most of area arrangements at the filter circumference has a plurality of through holes at regular intervals, the diameter of through hole has nothing in common with each other, the hole of similar diameter is positioned at the circumferential area of same longitudinal extension, the hole of maximum diameter is arranged in the zone that metallic seldom may enter, and the hole of minor diameter is arranged in the zone that the metallic most probable enters; And a circumferential area that does not have the longitudinal extension in hole is arranged in the filter; Each through hole all has one to import end Y at the filter cylinder outer wall, then has one to derive end at the filter cylinder inner wall, and intermediate portion is arranged with deriving between the end importing end, and it is bigger than intermediate portion to derive the diameter of holding.

2, a kind of improved filter according to claim 1 is characterized in that the intermediate portion of each through hole has tapering on a part of length, and this tapering is being derived the end end.

3, a kind of improved filter according to claim 2 is characterized in that, the half-angle of its tapering is 3.5 degree, and the length of taper is enough to make the circulation area in hole to be increased to twice.

4, a kind of improved filter according to claim 1 is characterized in that, fie screen be positioned at the outside and in order to the protection filter on each regional hole.

5, a kind of improved filter according to claim 1 is characterized in that, there is the circular end that imports in the hole.