CA1238031A - Valve housing - Google Patents

Abstract

VALVE HOUSING
Abstract of the Disclosure A valve housing has butt pipes for connection to a pipeline for defining therewith a passage for a flow of a fluid being conveyed, preferably of a slurry. A plura-lity of ribs are provided along the passage on the lower portion of the wall thereof, each rib extending transve-rsely of the passage. Each rib is of a tear-shaped confi-guration in its section taken along the longitudinal cen-terline of the passage a the enlarged portion of the rib facing toward the incoming flow of a fluid being conveyed.

Description

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~ his invsntion relates generall~ to plpe ~ra~sport sys-tems, and mDre particularly to a valve housingO
~ he valve housing embDdying ~he prese~lt inventiDn can ~ind application ~or conveying a slurrY i~ a pipe trans-port line by liquid and gaseous ~luids ~ he valve housing may also be utilizecl for transpor ting loose abrasive ma~erials and other ma~erials, such as liquids, gaseous materials, suspensions~ etcO
There is ~nown a val~e housing (cf. USSR Inventor' 9 Cerbiflcate No. 479,925) comprising arranged coaxially butt pipes for connection to a pipeline to ~orm therewith a straight-~low passage for a ~luid carrying abrasive 90 lids to be conveged -therethrough. Arranged in the upper portion o~ the valve housing to move in a vertical plane is a gate for blocking the straight-~low passage. ~he lo-wer p~rtion of the inner wall D~ the valve housing contai~s a pluralit~ of successive projections and recesses arran-ged le~gthwise o-~ the straight-~low passage. Each o~ tbe projections or ribs extends substantiall~ transvers~l~ o~
said straight-~low passage abaut a~ arc of a circle o~ nG
les~ than 120~
Each projection or rib has in a section passing thro-ug~ the longitudinal centerline o~ the straight-flow passa-ge a shape of a scalene trapezium. The ribs are fabrica-ted fr~m the sam~ material as bhe valve hou3ing and but~
pipes~ ~he ribs ~re intended to ~acilitate ~ormation on ~A
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t~le lo;;er Ol'~iOXl oi tLle inner wall of the valve housing o~ ~ bed of solid ,)articles, tnese solia ~alticles tending to setble anà Iest Detween ~he ribs and subsequently lay thel eu,l,on ~
'I'he provision of the settled bed oi solids prevents the lower portion of the inner wall of tne valve housing frorn being abrased by the particles carried by the fluid being conveyed. In order to reduce resistance to the flow and prevent pressure losses in the valve housing, it is preferable that the depth of the bed of settled particles be as sn-all as possible. Ilowever, at such a depth some larger solid palticles carri~d b~ the flow of fluid tend to penetrate the bed of settled solids.
Further, the ribs of the above valve housing are made of the same material as the housing and butt pipes and therefore are susc0ptible to fast ~ear by large abrasive particles penetrating the bed of smaller settled particles.
As a result of fast wear of the ribs 9 the service life of the valve housing and the butt pipes is considerably redu-ced.
'~he shape of the ribs in a section taken ~hrough the longitudinal centerline of the straight-flow passage of the above known valve ~ousing provides a bed o~ solid particles between the ~ibs that i8 not sufficiently stable especially at i~creased flow velocities under certain operating co~ditions, where~y the depth of the bed of -~; settled solids tends to become substan~ially less tha~

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the hei~ht OI' the ribs to result in accl~le,~ated ~i~ear of tne lo~ler ~ortion of tne ~-iall OL` ~he vc~lve housinO-lt is a~ object of -tie inverition 1,o ~rovide a vc~lve housinO ~herein ribs at tne lo~er inner wall portion thereo~ have a shape in a closs-section ta~en tnrough the lo~Oitudi~al ce~terlin~ o~ a strai~ht~flow passage inside the valve housinO wnich e~sures the formation thereo~ o~
a stable layer of SOlidsa This object is acco~lplished b~ that in a valve housing having butt pi~es for connection to a pipeline for .eorming therewith a straight--~low passage for a flow of a ~luid being conveyed therethIouOh, the lower portion o~ the inner wall of the strai~ht-flow passare havinO a plurality of ribs extending substantially tran~versely of the straiOht-flow passage 9 according to the inve~tion~ each o~ the ribs is tear-shaped i~ a cross-section taken through the longltudinal centerline of a straight-f`low passage, an enlarged portion o~ the rib facing toward the incoming flow of a ~luid bei~g conveyedl Thanks to the aforedescribed cross-sectional co~figu-ration of the r.bs the thickened portion o~ each such rib facing the incomlng ~low o~ fluid ~acilitates the settle-ment o~ solids before this thickened rib portion to ~orm a sta~le bed of soIids o~ the lower por~ion of the inner wall of the valve housing~ the depth of this bed remaining invariable in the course of extended operatio~ of the valve housing. Therewith~ larger ~olid particles carried by ~ 4 -3~

the flow in f~ct fail to ~,enetiate l~his `oed, ,i.~ile the ~edi-tself ~cts to ~rever!t t~l~ ribs afi~ -G;~e lo~;er iriller .alls o tne valve ~lousinO ~rom abrasion, ~n~ ear.
l;he ribs having tne aforedesclibecl closs-sectio~al corlfiguratio~ may be nard-faced on the i~WeI' portion of the in~er wall o~ the valve flousing 3 the rios being o~ a matelial di~Ierent from the ~aterial OI` the valve housing.
.F~re~erably, the ribs are ~abricated ~ro~ a weax-resis tant material~
~ his ~lear-resistant material provides ~or extended service life of the ribs and durability o~ the valve hou-sing.
Advisably, the sur~ace of each rib facing the i~co~ing Ylow of fluid beirlg conveyed is at a~ angle to a transve.Lse plane passing through the straight-flow passage, the value of this angle not exceedi~g the value o~ the ~riction a~gle of the solid particles carried b~ the ~luid agains~ the ~; ~ ribs~
: : ~he provision of such an a~gle for each rib ma~es the bed of solids settled on the lower inner wall of the passage quite stable, the dept~l of sucn a bed theref`ore being stable even at high velocitias of -the lluid flow.
Preferably, the height of each rib is ~ot in excess o~ 0.03 to ~.05 the ma~imum cross~sectional diameter of the straigh~-~low passage~
.Yhe~ the ratio o~ the height of each rib to the maxi-mum cros~-sectio~al size of the straight-flow passage or : --:

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the aia1eter o~` ~uch a ~assa e -jnen ic is substantiall~j ound i~ l~ss ~han ~lO~ tne ~ed of soli~s i~ of inSUI`LiCi-ent àe"th to colnpletely cover the ribs, ~;l~ich results in their fast I~iear.
Conversely, at the above ratio in e~cess of 0.05 the de~th of the bed of solids is quite considerable, although it reàuces the cross-sectional area of the straignt-flow passage resulting in increased h~draulic resistance and loss of pressure in the valve housing which a~ects its e~iciency.
In view o~ the foregoinG, the valve housing embodying the pIesent invention has an extended service life. ~lso, it is quite ef~icient, the eff`iciency being attained without a loss in pressure of the fluid being conveyed, ~hereas the costly wear-resistant material is used only ~or the ribs rather than for the entire valve housing~
~ he invention ~ill oe described now in greater detail with reference to speci~ic embodiments thereo~ taken in conjunction with the accompanying drawings~ in which:
~ ig. 1 is a longitudinal sectional view o~ a valve housing embooying the prese~t invenbion, Fig. 2 is a cross-section take~ along the line II-II
in Fig. 1;
Fig~ 3 îs a cross-sestion of a modified form of the valve housing according to the invantion ~herein the lower portion of a straight-flow passags h~s a recess with ribs ~::
arranged in this recess; and ,, ~23~3~

~ 4 is an ~nlallOed vie9'i of r~ectioIl.. in ~ig;. 10 .;i~n ieference to ~ig. 'l tile valve nousinC, e~bo~ing -the plesent invention co~lpI~ises coa~ialLy arran~ed on both sldes o~ the nousing butt ~ipes 2 for connection -to a ~ipeline (no-t sho-~n) to define therewith a straight-Llow paSsa~e (~) for a fluid, in ~his case pulp or slurry, to be conveyed t~rethrough.. The butt pipes 2 are co~nectable to the ~ipeline ~y means of flanges 4. In -the embod.iment bein~ described the butt pipes ~ are ~ade integral with the valve housing 1. Altelnatively, the butt pipes 2 ulay be connected to the ~ipeline by other ~own suitable mearls, such as threaded connections, welding, solderinO, etc.
Other alternative modifications rnay provide that the butt ~ipes 2 are rigidly secured bO the valve housing 1.
'~he bukt pi~es 2 are arran~ed to be in line with R
longitudi~al centerline 5 o~ the valve housing l~ ~ branch pipe 7 is ~urther provlded in the upper portion o~ the valve housing 1 to ~ollow an axis 6 passing perpendicula.rly relative to the longitudinal ctnterline ~, the branch ~ipe 7 accommodating a valving member 8 to L'it a valve seat 9 inside the valve housing 1. A groove or inner shoulder (not indicated ~y a re~erence numeral) is provi-ded at the inner wall o~ the housing 1 to receive the val-ve seat 9 a~fixable to the housing 1 by aDy known suitable means c The val~ing member 8 is arran~e~ in line with ~he vsrtical a~is 6 and en~age with the valve seat 9 by an an-3~

nul~r .,loj c-tion 1~ Jlovided on t~e peri~rierr.1 of tne val--`liLl~ mc.~l~en ~3 ~t tae si de tnereol I`acinO che valve seat 9.
-~ side of -tne v_lving member 8 o~,osit~ to the abovemen-tioned side thereof in the up~,er portion of the valving member 8 is generall-j a flat surlace 11 perpendicular to the lor,Oitudinal centelline 5 o~' the valve housing~ whe-reas in tne lov~er pOrbiOn of the valving member 8 this side is a flat surface 12 i~clined relative to the nori zont~l centerline 5. A cross-sectional area taken in pa-rallel with the horizon-tal longitudinal centerline 5 and substantially parallel with the vertical axis 6 at the lower portion of th0 v~lving member ~ is less -than a cross-sectional area taken in a similar manner in the upper portion o~ the valving member 8 thereby gradually increasing from the lowest end of the valving member 8 as seen in Fig. 1 upwards along the vertical axis 6.
In order to execute reciprocations, the valving mem-ber ~ is linked with a drive means (not shown) of any known suitable construction. 'l'his linkage to the drive means is effected tQrough a rod 1~ affixed to the valving member 8 by a~ known suitable threaded connection, such as the one shown at 14 in ~ig. 1. ~ recess 15 is provided in the lo-wer portion of the valve housing extending upwards to the longitudinal centerline 5 and serving to accom~lodate the valving member 8 when it assumes a dow~most position, that is when it closes or blocks the straight-flow passage ~.
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~ e c~lindlical L~cess ~5 ;_~enàs to tre i~i~ht-hand butt ipe 2 t ~ ough a tap~red conJlectiLr, ,ortiorl 16. ~'he val~,~inP ~ Der 5 iIl ibS down~ost .,osit;ion is ~;~aceà a certain distance L`rom -the lo~;Jer ,~;all of the cylindrical recess '15 9 i~f,areby a `~ea of soli~ parbicle5 of the S1UIrY
settled on che bottom of the passaOe ~ is causea to be shifted ri~t~ards to the butt pipe 2 thus maki~g it pos~
sible f'or the ~ember ~ to completely block the passage 3O
~ plurality o~ inner ribs 17 are arranged in the lo-wer portion o~ the passage 3O
~ ach of the ribs 17 extends cross-sectionally of the passage 3 about an arc o~ a circle o~ no less than 120, i~ this case this anOle being exactly '120, as seen best i~ Fig. 2.
~ eferri~g again to ~ig. 2, the ribs 'l7 are arranged directly on the lower portion of tha wall of the pass~ge 3 of the butt pipe 2.
: In another embodiment of the invention illustrated n ~ig. 3 the ribs 17 are arranged in a recess 17a made in lower portio~ of the wall of the passage 3.
~ uch an arrange~ent of' the ribs 17 in the recess 17a results in a reduced hydraulic resistance of` the valve hou~ing 1.
: ~ ~ach of the xibs 17 is tear-shaped i~ a sectio~ pas-si~g through the lon~i~udi~al centerli~e 5 of the passage 3, as seen best i~ Fig. 2. '~he thicker portion of each : rib 17 faces the incomi~O ~low o~ fluid ~eing conveyed , ~ ~38~3~

~lrough the passage ~, the direc~ion of this flow oeinO
indicated oy ~ in Ll;ig. 1.
The alo~edescLibed shape of the I'ibS 1'~ facilitates ~he settlement of solids before the thickened portion thereof.
L'he rlbs 1-~ are fabricated from a ~ear-resistant ma-terial hard~f~ced on the inner -~al.l of the passage 3.
This wear-resi~tant material extends the service life of the valve housinO, whereas hard-facing saves the amount of such costly material needed for forming the ribs.
,'~ith reference to Fig. 4~ surface 18 of each of the ribs 17 which ~aces the incominO Ylow of fluid is incli-ned at an angIe ~ to plane 19 passinO transversely of` the passa~e 3, the ~luid beinO conve~ed in this case being a slurr~ or mi~ture of solid mineral particles with ~Jater.
I~he angle ~ is equal to the angle of ~riction of the solid mi~eral particles carried by the fluid on the ribs 17. Experiments have shown that at this value o~ the angle ~ the depth of' the bed of solids settled between the ribs 17 is not diminished even ~hen the speed with which the fluld is co~veyed is increased, which prevents the lower portion of the passage ~ from being abrased or worn out.
~ ach rlb 17 has a heiOht h which is 0.04 the dlameter of the passage 3. ~t such a value of the height h of the ribs 17 the bed of settled solids prevents to a sufficie~k extent the lower portion oX ~he passage 3 ~rom premature ~3~13~

'~ieaL'; t.liS LLei~ ht oi ti~ L'iDS 1 ~ fu~th~-ir Lails to result in an inc' ~_e of L~-araulic , esls ta ,lce bO flo;/ ii~si~e tLle ~alve h~usinO 1 or loss o~ ~lessure taeIein~
~ l`he val~e housin~ accoIdinr~ -to the invention opelates in the follo~ing ma~ner.
'~;ihen the valving member 8 is moved up~l~rds, a port in the valve seat ~) opens for the fluid flow movi~g in the direction indicated by B to pass from the pipeli~e to the right butt ~ipe 2 as seen in Fig~ 1 and thereafter be conveyed t~ough the open valve seat ~ and escape from the v~lve housing 1~ '~his flow carries abrasive solids by virtue of the fact that, as is l~nown a hydrod~namic li~t force produced by the f'lo~v of fluid being conveyed e~ceeds the gravitatioL,al force of each solid particle.
~ince the velocit~ of the f`luid ~low in the -vicinity of the ribs 17 is less tha~ the flow velocity in pLovimity to the lo~g~tudinal centerline 5, this lift force is overcome by the gravitational force of the solid particles, whereby each solid particle tends to set-tle dow~ and be carried by the flow lengthwise of the passage 3. Il'here-with, the path of solid particles becomes curvilinear, as shown by C in Fig. 4. Upon collidin~ with the surface 18 of the rib 17 facing the flow~ each solid particle acts on the surface 18 with a force indicated b~ D. Components of the force D are force ~ ~o~mal to the surface 18 and f'orce F and tangential thereto. '~he ta~gential force F
is e~ual to the force E multiplied by the tan~ent o~ the :

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_nOle .~ le telldenCy OL- tne folce ~ to push the solid ~article up~JdIds is counGeIed Dy a loI~ce G 9 .~ihich is a friction ~orce OL` t~ie solid palticle against the surface 18 of` the rib 17, this force G being eqwal to the force F
~ul.ti~lied ~y the tangent of the friction angle.
~ ecause -the value of the angle ~ is substantially less than ~he angle of friction of the solids a~ainst the ribs 1~ the ~orce G is at an~ tiine 6reater than the force F and therefore these solids tend to settle bet~Jeen the rios 1'7 and maintain their settled ~osition even at increased velocity o~ t'le fluid bein6 conveyed, ~s a result, a stable bed o~ se~tled solids is formed servi~g to prevent the lower portion of the inner wall of` the valve housing ~'rom ~brasion a~d ~iear.
At the height of the ribs 17 o~ 0.04 the cross-sectio~
nal diameter 19 o~ the pc~ssage 3 the oed of settled so-lids prevents s~ficiently well the lower portion of the inner wall o~ the valve housing 1 from bein6 a~rased by such solids carried by the fluid flow while resulting in virtually no increase in t~e hydraulic resistance of the interior of the valve housing 1~
~ he valve housin~s embodying the present invention have shov~n exellent results whe~ tested for loos0 abrasi-ves:pi~e transport in the coal indust~y. S0rvice life of such valve housings exceeded sev0r~ fold that o~ the known valve housi~g constructions used ~or the same purpose without entailin6 a substantial increase in hydraulic re~-istance to the flow of fluids bein;~ co~ve~ed.- 12 -

Claims (4)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A valve housing for installation in a pipeline, having: butt pies for connection to said pipeline for defining therewith a straight-flow passage for a flow of a fluid being conveyed; a plurality of ribs provided along the straight-flow passage on the lower portion of its wall, each rib extending substantially transver-sely of the straight-flow passage; each of said plurality of ribs having in a section taken through the longitudi-nal centerline of the straight-flow passage a tear-shaped configuration, the enlarged portion of the rib facing to-ward the incoming flow of a fluid being conveyed.

2. A housing according to claim 1, wherein each of said plurality of the ribs is made of a wear-resistant material.

3. A housing according to claim 1, wherein the sur-face of each of said plurality of ribs facing toward the incoming flow a fluid being conveyed makes with the plane extending transversely of the straight-flow passage an angle which does not exceed the angle of friction of so-lid particles of a fluid being conveyed on the plurality of said ribs.

4. A housing according to claim 1, wherein the height of each of the plurality of said ribs is not in excess of 0.03-0.05 of the maximum cross-sectional dimension of the straight-flow passage.