US2808197A - Fan assembly - Google Patents

Description

L- FORGO v"2,308,197

FAN ASSEMBLY 2 sheets-sheet 1 Oct. t, 1957 Filed Dec 9 ma. w

'rNyENToR LASZLO ggf-'mfo- I ATroRNEYS- L. FoRGo FAN ASSEMBLY Oct. 1957 2 Sheets-Sheet 2 Filed Dec. 27, 1955 uvm motor Fig. 3

Fig. 4

INVENTOR LASZLO FORQO ATTORNEYS United States patent@ f Talalmanyokat Ertekesito ,VallalatyudapestyHungal-y, a Hungarian firm Application December 21, 1955, Serial No.- 5555681 "SCIa-ims.' (la2`30-120) This invention `'relates toV a'ffan assembly, Aparftitularly lto such adevice 4as :is adapted 1o'aircooled yeond'e'nse'rs of steampower-plants. In plants `of'this -`kind the'con- `densate is rnoved from antinje'ctioncondenser through a cooling system comprisingat least one pump'andheat 'exchange devicesfback to 'Said'inject'i'on Ycondenser where- `'ow through'the cooling .'systemthe air is moved "by lmeans' of afan. `At'the vdischarge side :ofj'said fan .there `is fprovided'a casing :or 'shell'formed, "on' the one' hand, "by acylindrical ca 'singrpo'rtion arranged coaxiallyfwit'hsaid fan and, on'the other 'hand,"by. adiverg'enft outlegportijom calte'd' diuse'r in' this .speeication and'in thegappended claims adjacent to sa'i'd "cylindricalgpor'tion andjopening,

.diffuserof the above mentioned kind in whichemeansfare provided adapted to 'draw offthe boundary' layerforrned 'on lthe inner surface "of 'the diffuser, Without. employing a separate fan or vveitilator'for 'this purpose.

According to -the inventionthe di-iuser. is dou-ble walled along the whole length of its divergent part, openings are provided inthe inner wall of -the diffuser'connecting the 5 discharge side .ofra fanarranged.-'atsth'e entrance Softhe dituser .with its intake.side. by...means.;of a bywygihis wall. 'fof `the diiuser.

Since `in steam-plants. witnhiglracaiiacity Eg'ratgluantities of cooling-airv-areto bemoved through the heat exchangers forming conduits for'the condensate, the fan assembly according to -this invention *will be' of ggreat dimensions, nthe -largest -diameter of the frusto-eonical 'diffuser'measuring-uptow2025meters In eerder to maintain a high eiiciency of the fan compelling the air over the cooling surfaces of the heat exchange device, a hollow cap of streamline form should be arranged over the hub of said fan on the discharge side of the fan. To avoid the forming of a stationary boundary layer around this cap and to cause further the air delivered by the fan to fill in the diffuser also in the vicinity of said cap, according to the invention openings are provided in the wall of said cap forming passages between the interior of the diffuser and the space inside the hollow cap this space communicating with the intake side of the fan. By these means the boundary layers which would form 2,808,197 VPatented Oct. l1, V19,57

ice

2 1" ont'th'e inner'surfacerof thecdiiuserV and Aonttl'ie outer j surface 4of :the -cap' 'arranged on `the-hub Aof Lthe-fan', -will be drawn 'olf-by lthe fan itself without (employingy separate 'devices-such as "af-separate ventilator "for" thispurpose.

5 Other objects of the invention v-filljappearhereina-fter, -thenove'l' A'features and Vcombinationsb'eingset*forth iin the appended claims. 'i Y' *I'n'the accompanying drawings:

*Figure y1` is aA vertical-'sectionaleview taken on'line `I--I wmf-Figure 2 iofone embodiment 'of thet'fanrassembly ac- .p'cordrngto' fthe invention, A I

Figure 2 is `a cross section taken `on lline II-"II `fof Figure v1, s Y l Figure 3 is 'avertical 'sectional'viewjofa'secondjem- "bo'dim'ent-"of theinvention, v Y. .Y Y.

Figurejtds afvertical `sectional-view of 'a 'third'em- 'bo'diment .of the Adiffu'seraccording jto `'the invention. Y In 'the variousjguresf'the 'sameueference 'characters denotethesameparta K L 'Referring' to'Figures 1 1an'd'2 thel reference number 1 ,.'des'ignates'the blades. 'of a fanh'l'oWing' air in thedirection. ofthe .arrows 20. The rbladres^ 1 "of vt'hepfan 'are l arranged .on ia spider keyed nto the :shaft "15"idr'iven"byg a motor. *The 'spider consists of'afhub 412 tand. a'rim 13 A connected together'by'means ofispo'kesr'l'i Integralwvith i the 'rim there is` provided A'a "ho1low"'cap '19 fthe .wall pf g this '.cap "being subdivided-'by `vslots 5111;,parallel A'ivi/ith one another. p Th'e detachedparts of the'cap 7'9; are 'connected to'on'e another'bymeans 'of ribs k'11j'provid "nsiudethe oe'hou'ow op a The shaft .1S is car-rieb @araba-1 bearing arrangedinacylindrical bradket"16','ithisbracket mounted upon. a' central hollow 'support' 3.0 'built' upgof 'concrete Pfor the Llike and resting upon 'anjappropriatefoundation "31' On this foundationlthereareerected posts``32 35jfsupportin'g a frame A'33, forming the vbase ofza dituser'sur- 'r'ounlin'gthe discharge sidejo'f 'thetandescri'bed above. Cooling 'ai'rs drawnibctween the cooling 'surfacesofheat exchangersit of .tt'he'kindz described in Amy 'copending 'applications Ser. :No: 5 55,682 liled""December "2`7,"'l9`55, 4OV`a`n`d'Se`r. No.`".55.5,"683., "December '2.7,' 1955 'and is ldi'scharged inthe 'dilfusen v The diifuser .forms part :of 'a 'casingi'or shell having `a `converging entrance-portion, a short ylindricalportion .and a divergi'ng outlet .portion 'all theseuportion's'being 'coaxial with me :shaft -1s of .the fran ,described above. gTh'eldive'i-ging portion .ofthe casing, forming 'theidiius'er proper., `i`s 'adoblewalled body, consisting of an inn'er wa'llZ rnade of. concrete .and an 'outer wall )4 made..'of Y's'he'et metal and c onnec'te'dto the 'inner 'wall 'b y means of "struts"`29 disposed ...in the 'sp'acef'S 'between'thetwo wllsfzand 4. The upper -edge of theeouter wall '4 is 'lan'gedall around "andtightly connecte'dto the` inner wall 2 ,by any suitable .means so as to3prevent"1eakage `at.tl`1is `,.junctionQofrthe `two walls. Y Y u "'.The outer "w`a`ll4 is a plain 'one vcompletely separating the. space'S fromthe atmosphere. ".Thefinner w'allzis subdivided 'by Imeans 'of-slots `3 disposedalong .parallel circles 'andfforming' openings fthrou'gh which" the space 'inside'.thydilruser communicates'with thejspaee Sjinside ftheV doiibleewalll v4. 5 Sincefthe space'f5"oper 1s atmthentakefs el-:oif' die fan through ajriyngishapedjgapithe ""sp'ces 3'forms-"a 4`byfway '-connectingwiree'slots S'ewlth the intake side of the fan. Thus the air which would form a boundary layer on the inner surface of wall 2, is drawn oi by the fan itself.

Preferably the cross section, i. e. the width of the slots 3 decreases proportionally to their distance from said fan that is proportionally to the increasing of the pressure inside the diffuser. In order to control the quantity of the air drawn off in the direction of the arrows 21 through the slots 3 from the innerY surface of the Wall 2, adjusting means may be made of concrete.

provided in the diffuser adapted to control the cross section of the space 5 near the opening 22 connecting this spcae with the intake side of the fan. For this purpose in the embodiment shown in Figure 1 there is provided a ring-shaped slidable member 6 in the enlarged lower end 23 of the wall 2 which may be lowered into the channel 7 or lifted therefrom, thereby reducing or increasing the sectional area of flow.

In fan assemblies of great dimensions eddies forming behind the fan may cause considerable eddy current losses. In order to avoid these losses I prefer to arrange Ythe hollow cap 9 of stream line form described above.

the slots 10 in the hollow cap 9, the space inside the cap and between the spikes 14, the air that would form a boundary layer around the cap is drawn off and is delivered to the intakeY side of the fan through the gap 17. This air ows in the direction of the'arrows 24. The quantity of the air drawn off from the outer surface of the cap 9 may be controlled by a ring-shaped member 18 located near the slot 17 inside the bracket 16. By lowering and lifting the slidably mounted ring 18 the width of the slot 17 will be increased or reduced.

The embodiment of the fan assembly according to the invention shown in Figure 3 differs from that of Figures l and 2 only in that the openings in the inner wall 2 of the diffuser are holes 27 instead of slots, the holes 27 coaxial with the shaft of the fan. Similar holes 35 are provided in the wall of the cap 9 over the hub of the fan.

Preferably the total cross section of the holes 27 disposed along each of the coaxial rows decreases propor tionally to the distance of the rows from the fan, i. e.

frame of the diiuser is formed by the wall made of concrete.

The invention makes it possible to build up cooling structures, such as cooling towers for steam plants of great capacity wherein the cooling air is moved by a fan or ventilator through a diffuser having an aperture of more than the usual 8 12", even up to 90-180 and though operating with good efficiency and having a short length. Therefore it is especially adapted for fan assemblies having very great dimensions as are the dimensions of air-cooled steam condensers.

Since the hollow cap 9 is integral with the rim 13 of the spider forming the hub of the fan, so it rotates together with the rotor of the fan and no special supporting mountings are needed as applied in fan assemblies having a stae.

tionary or tixed Cowling in front of the hub of the rotor. Obviously those skilled in the art may make various changes in the details and arrangement of parts without.

`Vdeparting from the spirit and scope of the invention as delined by the claims hereto appended, and I therefore wish not to be restricted to the precise constructions herein disclosed.

HavingV thus described and shown various embodiments i of my invention, what I claim is:

v the discharge side of said fan, said diffuser having a plain being disposed along circles parallel to one another and outer wall and an inner wall provided with openings disposed along circles parallel to one another, the crosssection of said openings decreasing proportionally to theirV distance from the fan, said openings forming pasl; sages between the interior of the diiuser and the inner space between its outer Wall and inner wall, said inner i space being connected with the intake side of the fan.

proportionally to the increasing of the pressure of the air inside the diifuser. Since this pressure increases proportionally to the distance from the fan, the difference between the pressure of the air in the diuser and the pressureof the air on the intake side of the fan increases proportionally to the distance of the holes 27 from the fan. To maintain, however, a constant valueV of the quantity of the air drawn off through subsequent rows of openings, the cross section of the openings is to be diminished proportionally to said distance and increase of air pressure inside the dituser. For this pnrpose,'in the embodiment of Figs. 1 and 2 the width of the slots 3 is to be varied and in the embodiment of Fig. 3 either the diameter of the holes'27 or their number in the various rows is to be likewise varied. In the embodiment according to Figure 3 the space S between the two walls 2 and 4 communicates through openings 8 with the intake side of the fan.

In the two embodiments of the invention shown in Figures 1-3 the double walled diffuser has an inner wall 2 made of concrete and an outer wall 4 made of sheet metal. In the embodiment shown in Figure 4 the inner wall 36 is made of a perforated sheet metal and is supported byvmeans of bolts 19 on the plain outer wall 28 A The upper end of the space 5 between the two walls 36 and Z8 is closed by the bordered edge 37 of the metallic inner wall 36. In both cases the solid 2. A fan assembly as claimed in claim l, in which said openings provided in the inner wall consist of coaxial ring-shaped slots forming circles parallel to one another.

3. A fan assembly as claimed in claim 1, in which the openings in the inner wall are disposed along circles parallel to one another and coaxial with the shaft of the fan.

4. A fan assembly as claimed in claim 1, in which at least one of the inner and outer walls is made of concrete and forms the solid frame of the diffuser.

5. A fan assembly as claimed in claim l, in which a hollow cap isY arranged on the discharge side of the fan and permanently attached to the hub of said fan and opensoV ings are provided in the Wall of said hollow cap in order to form passages between the interior of the diffuser and the inner space of the hollow cap, said inner space being connected with the intake side of the fan.

References Cited in the tile of this patent UNITED STATES PATENTS France Jan. 4, 1950

Images