CA1041834A - Axial flow inducers for hydraulic devices - Google Patents
Axial flow inducers for hydraulic devicesInfo
- Publication number
- CA1041834A CA1041834A CA234,200A CA234200A CA1041834A CA 1041834 A CA1041834 A CA 1041834A CA 234200 A CA234200 A CA 234200A CA 1041834 A CA1041834 A CA 1041834A
- Authority
- CA
- Canada
- Prior art keywords
- inducer
- flow
- axial flow
- blade part
- pump
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/18—Rotors
- F04D29/22—Rotors specially for centrifugal pumps
- F04D29/2261—Rotors specially for centrifugal pumps with special measures
- F04D29/2277—Rotors specially for centrifugal pumps with special measures for increasing NPSH or dealing with liquids near boiling-point
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
- B01F27/60—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a horizontal or inclined axis
- B01F27/71—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a horizontal or inclined axis with propellers
- B01F27/711—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a horizontal or inclined axis with propellers co-operating with stationary guiding means, e.g. baffles
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
ABRIDGEMENT
An axial flow inducer for hydraulic devices is disclosed.
the inducer is coaxially arranged in front of a fluid suction inlet side of a main impeller of an hydraulic device, for example, a pump and constituted by at least two axial flow blade parts which are constructed and arranged so as to prevent an occurrence of noise over all flow amount region of the impeller.
An axial flow inducer for hydraulic devices is disclosed.
the inducer is coaxially arranged in front of a fluid suction inlet side of a main impeller of an hydraulic device, for example, a pump and constituted by at least two axial flow blade parts which are constructed and arranged so as to prevent an occurrence of noise over all flow amount region of the impeller.
Description
la~l~3~
This inven~ion relates to pump inducers and more particularly to an axial rlow inducer coaxially arranged upstream an impeller of the pump and adapted for use in a hydraulic device such as a centrifugal pump and the ~ke.
In a hydraulic device such as a pump and the like, it has been the common practice to use an axial flow inducer for the purpose of signi~icantly improving the fluid suckin3 cha~acteristic of the hydraulic device.
ffl e ax~al flow inducer of this kind, however, has such the dis--advantage that an intense pulsating noise occurs in a pump suction pipe over its small flow amount region ~ue to the restricted delivery condition.
In addition, this pulsation becomes increased as the suction presaure of the pump is decreased until a sort of water hammer occurs in the pu~ suction pipe. As a result, there is a risk of the suction pipe being broken down.
qhe inventors have recognized by thelr enthl~siastic study and experiments that, over the small flow amount region of the pump, the pulsations occur in the suction plpe owing to the fact that the design flcw amount of the inducer is defined to a value which is about three times larger than that o~ a main impeller, and as a result, a fluid counter flow Oeccn-s considerably increased at that inducer part of the pump which corresponds to the small flow ancunt re~ion.
In order to oveicone such difficulty, the in-~entors have recognizel by their further study and experiments that lf the des~gn flow amount ~ -Or the lnducer is defined to a value which is wlthin a range of 1.0 to 2 times the des~gn flow amount Or the main im~eller, the suction stroke of the inducer can be lmproved wlthin a least poss~ble limit. In this case, even when the rlow amcunt sllghtly exceeds the design flow a~ount and hence the ir~ucer ~troke become8 somewhat decreased, an occurrence of the ~luid counter flow, thQt 18, an ccourrence Or cavltatlon can be ~ade extremely small.
.
This inven~ion relates to pump inducers and more particularly to an axial rlow inducer coaxially arranged upstream an impeller of the pump and adapted for use in a hydraulic device such as a centrifugal pump and the ~ke.
In a hydraulic device such as a pump and the like, it has been the common practice to use an axial flow inducer for the purpose of signi~icantly improving the fluid suckin3 cha~acteristic of the hydraulic device.
ffl e ax~al flow inducer of this kind, however, has such the dis--advantage that an intense pulsating noise occurs in a pump suction pipe over its small flow amount region ~ue to the restricted delivery condition.
In addition, this pulsation becomes increased as the suction presaure of the pump is decreased until a sort of water hammer occurs in the pu~ suction pipe. As a result, there is a risk of the suction pipe being broken down.
qhe inventors have recognized by thelr enthl~siastic study and experiments that, over the small flow amount region of the pump, the pulsations occur in the suction plpe owing to the fact that the design flcw amount of the inducer is defined to a value which is about three times larger than that o~ a main impeller, and as a result, a fluid counter flow Oeccn-s considerably increased at that inducer part of the pump which corresponds to the small flow ancunt re~ion.
In order to oveicone such difficulty, the in-~entors have recognizel by their further study and experiments that lf the des~gn flow amount ~ -Or the lnducer is defined to a value which is wlthin a range of 1.0 to 2 times the des~gn flow amount Or the main im~eller, the suction stroke of the inducer can be lmproved wlthin a least poss~ble limit. In this case, even when the rlow amcunt sllghtly exceeds the design flow a~ount and hence the ir~ucer ~troke become8 somewhat decreased, an occurrence of the ~luid counter flow, thQt 18, an ccourrence Or cavltatlon can be ~ade extremely small.
.
- 2 -~ ., An ob~ect of the invention, thererore, is to provide an axial flow inducer which can prevent an occurrence of noise over all flow amount region -- Or the main impeller.
An aspect of the invention is to provide an axial flo~J inducer coax1~11y arranged in front of a main impeller and having a desi~n flow amount which is about 1.0 to 2 times the design flow amount Or the main impeller.
The inventors have found out by their study and experiments that ir an axial flow blade is constituted by at least two axial llow blade parts and provision is made of a sleeve havin~ one end secured to the outer peripheral edge Or that axial flow blade part which is located near tne fluid inlet end of the inducer and having another end extending toward the fluid inlet side and bent inwardly so as to forn a barrier, the fluid counter ~low produced at the main impeller of a hydraulic device, for example, a pump and thc lilcc! ca-. b~ confincA into a local c~unter flow between the main impeller and an axial flow blade part ad~acent thereto and also the fluid counter -flow produced in front of the front axial blade part can be confined into .~-a space ~ormed by the sleeve which is rotated together with the inducer.
As a result, it ls possible to prevent the ~luid puls~tion and hence the noise flrom being produced in the suction pipe over all ~low amount region of the main impeller irrespective of the deslgn flow amount of the inducer.
Another ob~ect of the invention, therefore, is to provide an a~ial flow inducer which can confine the fluid counter flow produced at the Juctlon side of the m3in i~peller into a local counter flow so as to prevent 25 an occurrence o~ nolse over all rlOw amount region of the main ~mpeller.
Another a8pect of` the invention is to provide an axial l~low inducer ¢oa~lally arrarged in ~ront Or a lrain impeller, coTprising a sleeve having~ :
one end 8ec~ to the outer peripheral edge Or the inducer and another etld bÇ!nt irlWar~lly 80 as to fonn a barrier.
In addltlon, the inventors have ~ourJd out by their study and . .
. :' .
.
An aspect of the invention is to provide an axial flo~J inducer coax1~11y arranged in front of a main impeller and having a desi~n flow amount which is about 1.0 to 2 times the design flow amount Or the main impeller.
The inventors have found out by their study and experiments that ir an axial flow blade is constituted by at least two axial llow blade parts and provision is made of a sleeve havin~ one end secured to the outer peripheral edge Or that axial flow blade part which is located near tne fluid inlet end of the inducer and having another end extending toward the fluid inlet side and bent inwardly so as to forn a barrier, the fluid counter ~low produced at the main impeller of a hydraulic device, for example, a pump and thc lilcc! ca-. b~ confincA into a local c~unter flow between the main impeller and an axial flow blade part ad~acent thereto and also the fluid counter -flow produced in front of the front axial blade part can be confined into .~-a space ~ormed by the sleeve which is rotated together with the inducer.
As a result, it ls possible to prevent the ~luid puls~tion and hence the noise flrom being produced in the suction pipe over all ~low amount region of the main impeller irrespective of the deslgn flow amount of the inducer.
Another ob~ect of the invention, therefore, is to provide an a~ial flow inducer which can confine the fluid counter flow produced at the Juctlon side of the m3in i~peller into a local counter flow so as to prevent 25 an occurrence o~ nolse over all rlOw amount region of the main ~mpeller.
Another a8pect of` the invention is to provide an axial l~low inducer ¢oa~lally arrarged in ~ront Or a lrain impeller, coTprising a sleeve having~ :
one end 8ec~ to the outer peripheral edge Or the inducer and another etld bÇ!nt irlWar~lly 80 as to fonn a barrier.
In addltlon, the inventors have ~ourJd out by their study and . .
. :' .
.
- 3 -1041~3~
experiments that the following measures can obviate the difficultY of signiflcantly increase the fluid counter flow produced at the inducer part over the low flow amount region. That is, if provision is made of at least two stages of axial rlow blades including a front stage axial flow blade ~art and a rear stage aYial flow blade part connected in cascade and having blade'angles dlff~rent from one stage to the other st~ge, the ~lade angle of the front stage aXial flow blade part iocated at the fluid suctlon inlet side being made considerab~y small so as to make the rèar stage axial flow blade part larger in the blade angle than the flront stage axial flow blade part, if the rear stage axlal flow blade part is separated fro~ the front ' stage axial flow blade part by a sultable dlstance, and lf the outer dlameter . cf the rear stage axial flow blade part ls made smaller than that of the .. front stage ax~l flow blade part by a suitable dimension, when a portion of the fluid introduced fram the front stage axial flow blade part into a ~5 pump chanber lnlet causes a fluid counter flow,`the rear stage axial flow blade part can easily suck the fluid counter flow and can make it circulate again'and the rront stage axial flow blade part serves as a barrier to suppress the riuia counter flow fram entering into the pump suction pipe, . thereby'preventing a flu.ia pulsatlon in the pump suction plpe and hence.ao rellably preventing an occurrence of nolse during operation of the pump.
. A further obJect of the invention, there~ore, is to provide an . improved axial flow inducer which can confine a fluid counter flow produced at the suction side of the main impeller into a local fluid counter flo~l and hence which czn prevent an occurrence of noise over all fluid flow region.
A further.feature of the invention is the pro~rision o~ an axlal ~low inducer comprising at least two st~ges of axial flow blades including ~
S a front stage axial flow blade part located at the fluid inlet side .~.' and a rear ~taee axial flow blade part, the blade angle o~ the front stage : :
axial ~low blade part being made smaller than that of the rear stage axial 34 flow blade part so as to cause a fluid counter flow produced by a rotatior. of a ,' ' ' ~ ` - 4 - . ~
104~34 main impeller of a hydraulic device to be sucked by the rear stage axial flow blade part.
- The use of the measure of mak~lg the ~lade angle of the frontstage axial flow blade part considerably small c~uses to produce a fluid counter flow in front of the front stage axic~l flow blade part and hence causes to generate a nolse.
m e inventors have found out that lf provision is made Or a barrier in front of the front stage axial flow blade part by a suitable means, it is also possible to accelerate a re-circulation of the fluid counter flow ~0 and operate the main impeller without producing any noise over all flow region.
A still further feature of the lnvention, therefore, is the provislon of an axi~l flow inducer comprlsing further a barrier provided in front Or the front stage axial flow blade part.
Other ob~ects and advantages of the present invention will become - 15 apparent as the detailed description thereof proceeds.
s lhe invention will now be described ln greater detail with Y reference to the acccmQanDing drawings, wherein:
Pig. 1 is a longitudinal sectional view of one embodiment of . ~... .
an axial flow inducer according to the $nvention applied to a pump, 20~ Fig. 2 is a longitudinal sectlonal view of another embod~ment of the axial flow inducer according to the invention; and FYg. 3 to 7 are longitudinal sectional views of further embodiments ;~ Or the axial rlow inducer accordlng to the i~v~ntion, respectively.
~Ref~rring to Fig. 1, refelence numeral 10 designates a pump --j ~ ca~ing ln which 1s Qrranged a main impeller 14 secured to a rotary shaft 12 rotatably Journaled by the pump casin~ 10. In front of a fluid suction lnlet slde Or the main impeller 14 ls coaxially Qrroneed an inducer 16.
. , - In the inventlon, the inducer 16 is constructed such that its dbsl~n ~lc~r amcunt i8 about 1.0 to 2 tlmes the deslgn flow amount of the ,~ . , ,. . - .
~s ~ 5 ~ ~
" ,~,, , . - :
, ~ , -~ 104~34 maln impeller 14.
; The design flow amount of the inducer 16 thus derined makes it possible to prevent an occurrence of fluid counter flow in the pump suction inlet part ~here the inducer is located when the pump is operated in a manner j such that the pump flow amount is somewhat lar~er than the design ~low amount Or the inducer, thereby preventing an occurrence of cavity.
In the present emb~diment, a barrier plate 22 ls sandwiched between a pump suction inlet part 18 of the pump casing 10 and the suction pipe 20.
` The barrier plate 22 serves to effectively prevent the ~luid counter flow produced along the inside wall ~urrace o~ the pump inlet part 18 fram being reached lnto the suction pipe 20, thereby preventing a noise ~ollowed by the fluld counter flow.
In Fig. 2 is shown another embodiment of the invention. In the present lnvention, the pump suction inlet part 18 of the pump casing 10 is provided ,.
-l5 at its front end with a flange-like barrier 24. The present embodiment is capable of preventing the nolse caused by the fluid counter flow in the same manner as in the previous embodlment.
¦ As stated hereinbefore, the use of measure of de~ining design fl~J
, amount of the in~ucer to a value which is 1.0 to 2 times the design flo:, ~0 amount o~ the main impeller provide~ the important advantage that the cccu mence of noise can reliably be prevented over all flow amount region o~ themaln impeller. --~. --` In Flg. 3 is s~nwn a further embodim~nt of the invention. In the Fresent inv~ntlon, provislon is made o~ a sleeve 26 having one end secured to :~
¦ ~ the outer perlp~eral edge or a front ax~l flow blade part 16a and another end bent inwardly ~o as to rorm a barrier 28. ~ ~
he provislQn o~ the cyl~ndrical barrier 28 located ln ~ront o~ the -~`
,; 8wtlon 81de Or the inducer 16 and secur~d to the suctlon side o~ the lnducer 16 makes it posælble to cause the rluld counter flow produced at the 5 ~0 81de Or the main impell~r 14 to clrculate again along a rear axial flow blade ,, ~ .
~ - 6 -- .
` , ` ` ~ . . . .. ": .` : ` ` ` -c 10~1~34 part 16b and hence confine the fluid counter flow into a local rluid counter flow and also possible to cause the fluid counter flo~r produced near the front axlal rlow blade part lha to circulate again in the sleeve 26 by the action Or the barrier 23 provided for the sleeve 26.
The use Or the measure described above provides the important advantage that the fluid counter flow produced at the inducer 16 is rellably prevented from being delivered into the Muid suction pipe, so that the noise ; caused by the rluid counter flow can completely be prevented over all M ow I amount reglon durin~ the operatlon of the pump.
That ls, the sleeve 26 provided in front of the inducer 16 and having the ba~rler 28 is rotated together with the inducer 16, so that the fluid counter flow produced in front of the nducer 16 ls prevented from ; producing a secondary flow. In addltlon, the fluid ir.troducsd into the lnducer i6 is sub~ected to the actlon of thè sleeve 26 prov~ded for the outer i5 perlpnery edge of the inducer lE to effect a forced re-circulation of the rluld cownter flow within a region in which ~ne ln~ucer 16 is located, thereby reliably preventing the pulsatlon of the fluid in the suction pipe -~
of the pump.
The ~resent embodiment is simple in constructlon and easy in nEnuracture an~ can be applied to hydraulic devices such as pumps having varlous ~inds of capacity irrespective of the design flow a~cunt of the inducer.In Fig. 4 is shown a still further embodimer.t of the invention.
i In the present embodiment, the inducer 16 ls constltuted by at least two ~ -- - stages Or axlal rlow blade parts including, rOr example, a front stage axial -~ rlow blade part 16a and a rear stage axial ~low blade part 16b which ~e ~ ~
dlrrerent ln blade angle~ rrom each other. - -s- The blade angle of the front stage axlal flow blade part 16a located at the rluid suctlcn inlet side is made extremely small whlle the blade angle Or the rear ~tage axial rlow blade part 16b is made large.
In t,hls case, 1~ i8 prerer~ble to define a gap C betw~en the cuter peripheral ' - 7 -., .
, 1041b~34 edge of the front stage axial flow blade part 16a and the insi~e ~lall surface s of the inlet of the pump cha~ber as small as possible.
t In addition, ~n axial distance 1 bet~Jeen the front stage axial flow blade part 16a a~d the rear stage axial flo~ blade part 16b is made equal to 0.05 to G.15 times smaller tl~an a d~ameter D ~f the axial flow b ade of the inducer 16.
In order to easlly define the axial distance 1, the front stage axial flow blade part 16a is made separate from the rear stage axial flow blade part 16b and detach~bly connected to the latteI~.
If the flui~ introduc~d from the front s'~ge axial ~low blade ¦ part 16a into the pump chamber lnlet produces a fluid counter flow between the rear stage axial flQW blade 16b and the maln impeller 14, the present embodiment makes it possible to easily suck the fluld counter flow l~to a space formed between the frcnt stage axial flow blade part 16a and the rear stage axial flow blade part 16b and effect a re-circulation of the ~luid.
¦ As a result, a noise caused by the fluid counter flo~ extended over a wide - region can effectiv~ly be prevented.
Dn Flg. 5 ls shown another embodiment of the invention. In the , pre&ent embodlment, the outer d~ameter D2 ~ the rear stage axial flow blade part 16b is made smaller than the outer diameter Dl or the front stage axial flcw blade part 16a for this purpose of easily sucklng the fluid counter flow --prcduced at the pump chamber inletinto a spece for~ed between the front stage axial flow bl~e part 16a and the rear stage axial flow blade part 16b.
The present embodiment can ~revent the nolse in the same manner as in the j -~
case Or the prevlous ambodinents. -In the present emkodlment, the front stage axial flow blade part 16a ~ay be made lntqgra} with the rear stage axial flow bl~de part l~b.
In addltlon, lt 1~ most prererable to derine a dirference between the outer di~T~ter Dl Or the front sta~e axial flow blade part 16a and the outer dlameter D2 Or the rear stage axial flow blade part 16b by a formula given by , i ~ - 8 -, , : .
.
. ", . . i , . -~ 0 ~ 1 ~ 3 4 Dl - D2 = (-3 to O.l)Dl.
In the present embc~i~ent, the fluid whlch has been introduced into t,he inducer 16 causes the Muid counter flow to re-circulate in the space - form~d between the front sta~e axial flotJ blade part 16a and the rear stage - --axial flow blade part 16b, thereby confining the fluid counter flow into a local fluid cou~ter ~low.
But, the above mentioned measures could not suppress a fluid counter flow produced ln front of the front stage axial flow blade part.
In the invention, in order to suppress .such counter flow, provision is made of a barrier in front of the front stage axial flow blade part 16a.
In Fig. 6 is shown one 6~bodiment of providing such a barrier.
In the present embodiment, a barrier plate 22 is sandwiched between the pump sucticn inlet part 18 of the pump casing 10 and the suction pipe 20.
The present embodiment provides a w~y of simply arranging the barrier plate.
In Fig. 7 ls shown another ~bodiment of providing the barrier. -:
In the present embodi~ent, the front stage axial flow blade part 16a is provlded at its outer peripheral edge with a sleeve 26 having one end secured thereto. Ihe sleeve 26 is extended along a fluid inflow direction, another ~ ;
end of the sleeve 2S being bent inwardly so as to form a barrier 28. ~
In the present embodiment, the wall part of the sleeve 26 which ~ :
.rcrms the barrier 28 is rotated to~ether with the inducer 16, so that it is possible to e~fectively suppress the fluid counter flow by the inside space Or the sleeve 24.
As stated h~reinbefore, the axial flow inducer according to the lnventlon is capable of confining all mcdes of fluid counter M ow produced at the ~ndu~er part into respective local counter streams, and of preventing -the rluld counter flcw from being sprea~ over all fluid flow region, th~reby --oyerating the pump without noise in smooth nEuuler.
The axial flow inducer according to the inventlon has such advantages that lt 18 ~imple in construction, and that it can easily and _ g _ ", ,, ~0~1~34 cheaply manufactured in a mQ5s productlon scale.
or course, the invention is not limited to the above example3 as described and represented. From these examnles other modes and rorms of realization can be foreseen without dep~rtir~ rro~ the spirit of the inventlon.
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experiments that the following measures can obviate the difficultY of signiflcantly increase the fluid counter flow produced at the inducer part over the low flow amount region. That is, if provision is made of at least two stages of axial rlow blades including a front stage axial flow blade ~art and a rear stage aYial flow blade part connected in cascade and having blade'angles dlff~rent from one stage to the other st~ge, the ~lade angle of the front stage aXial flow blade part iocated at the fluid suctlon inlet side being made considerab~y small so as to make the rèar stage axial flow blade part larger in the blade angle than the flront stage axial flow blade part, if the rear stage axlal flow blade part is separated fro~ the front ' stage axial flow blade part by a sultable dlstance, and lf the outer dlameter . cf the rear stage axial flow blade part ls made smaller than that of the .. front stage ax~l flow blade part by a suitable dimension, when a portion of the fluid introduced fram the front stage axial flow blade part into a ~5 pump chanber lnlet causes a fluid counter flow,`the rear stage axial flow blade part can easily suck the fluid counter flow and can make it circulate again'and the rront stage axial flow blade part serves as a barrier to suppress the riuia counter flow fram entering into the pump suction pipe, . thereby'preventing a flu.ia pulsatlon in the pump suction plpe and hence.ao rellably preventing an occurrence of nolse during operation of the pump.
. A further obJect of the invention, there~ore, is to provide an . improved axial flow inducer which can confine a fluid counter flow produced at the suction side of the main impeller into a local fluid counter flo~l and hence which czn prevent an occurrence of noise over all fluid flow region.
A further.feature of the invention is the pro~rision o~ an axlal ~low inducer comprising at least two st~ges of axial flow blades including ~
S a front stage axial flow blade part located at the fluid inlet side .~.' and a rear ~taee axial flow blade part, the blade angle o~ the front stage : :
axial ~low blade part being made smaller than that of the rear stage axial 34 flow blade part so as to cause a fluid counter flow produced by a rotatior. of a ,' ' ' ~ ` - 4 - . ~
104~34 main impeller of a hydraulic device to be sucked by the rear stage axial flow blade part.
- The use of the measure of mak~lg the ~lade angle of the frontstage axial flow blade part considerably small c~uses to produce a fluid counter flow in front of the front stage axic~l flow blade part and hence causes to generate a nolse.
m e inventors have found out that lf provision is made Or a barrier in front of the front stage axial flow blade part by a suitable means, it is also possible to accelerate a re-circulation of the fluid counter flow ~0 and operate the main impeller without producing any noise over all flow region.
A still further feature of the lnvention, therefore, is the provislon of an axi~l flow inducer comprlsing further a barrier provided in front Or the front stage axial flow blade part.
Other ob~ects and advantages of the present invention will become - 15 apparent as the detailed description thereof proceeds.
s lhe invention will now be described ln greater detail with Y reference to the acccmQanDing drawings, wherein:
Pig. 1 is a longitudinal sectional view of one embodiment of . ~... .
an axial flow inducer according to the $nvention applied to a pump, 20~ Fig. 2 is a longitudinal sectlonal view of another embod~ment of the axial flow inducer according to the invention; and FYg. 3 to 7 are longitudinal sectional views of further embodiments ;~ Or the axial rlow inducer accordlng to the i~v~ntion, respectively.
~Ref~rring to Fig. 1, refelence numeral 10 designates a pump --j ~ ca~ing ln which 1s Qrranged a main impeller 14 secured to a rotary shaft 12 rotatably Journaled by the pump casin~ 10. In front of a fluid suction lnlet slde Or the main impeller 14 ls coaxially Qrroneed an inducer 16.
. , - In the inventlon, the inducer 16 is constructed such that its dbsl~n ~lc~r amcunt i8 about 1.0 to 2 tlmes the deslgn flow amount of the ,~ . , ,. . - .
~s ~ 5 ~ ~
" ,~,, , . - :
, ~ , -~ 104~34 maln impeller 14.
; The design flow amount of the inducer 16 thus derined makes it possible to prevent an occurrence of fluid counter flow in the pump suction inlet part ~here the inducer is located when the pump is operated in a manner j such that the pump flow amount is somewhat lar~er than the design ~low amount Or the inducer, thereby preventing an occurrence of cavity.
In the present emb~diment, a barrier plate 22 ls sandwiched between a pump suction inlet part 18 of the pump casing 10 and the suction pipe 20.
` The barrier plate 22 serves to effectively prevent the ~luid counter flow produced along the inside wall ~urrace o~ the pump inlet part 18 fram being reached lnto the suction pipe 20, thereby preventing a noise ~ollowed by the fluld counter flow.
In Fig. 2 is shown another embodiment of the invention. In the present lnvention, the pump suction inlet part 18 of the pump casing 10 is provided ,.
-l5 at its front end with a flange-like barrier 24. The present embodiment is capable of preventing the nolse caused by the fluid counter flow in the same manner as in the previous embodlment.
¦ As stated hereinbefore, the use of measure of de~ining design fl~J
, amount of the in~ucer to a value which is 1.0 to 2 times the design flo:, ~0 amount o~ the main impeller provide~ the important advantage that the cccu mence of noise can reliably be prevented over all flow amount region o~ themaln impeller. --~. --` In Flg. 3 is s~nwn a further embodim~nt of the invention. In the Fresent inv~ntlon, provislon is made o~ a sleeve 26 having one end secured to :~
¦ ~ the outer perlp~eral edge or a front ax~l flow blade part 16a and another end bent inwardly ~o as to rorm a barrier 28. ~ ~
he provislQn o~ the cyl~ndrical barrier 28 located ln ~ront o~ the -~`
,; 8wtlon 81de Or the inducer 16 and secur~d to the suctlon side o~ the lnducer 16 makes it posælble to cause the rluld counter flow produced at the 5 ~0 81de Or the main impell~r 14 to clrculate again along a rear axial flow blade ,, ~ .
~ - 6 -- .
` , ` ` ~ . . . .. ": .` : ` ` ` -c 10~1~34 part 16b and hence confine the fluid counter flow into a local rluid counter flow and also possible to cause the fluid counter flo~r produced near the front axlal rlow blade part lha to circulate again in the sleeve 26 by the action Or the barrier 23 provided for the sleeve 26.
The use Or the measure described above provides the important advantage that the fluid counter flow produced at the inducer 16 is rellably prevented from being delivered into the Muid suction pipe, so that the noise ; caused by the rluid counter flow can completely be prevented over all M ow I amount reglon durin~ the operatlon of the pump.
That ls, the sleeve 26 provided in front of the inducer 16 and having the ba~rler 28 is rotated together with the inducer 16, so that the fluid counter flow produced in front of the nducer 16 ls prevented from ; producing a secondary flow. In addltlon, the fluid ir.troducsd into the lnducer i6 is sub~ected to the actlon of thè sleeve 26 prov~ded for the outer i5 perlpnery edge of the inducer lE to effect a forced re-circulation of the rluld cownter flow within a region in which ~ne ln~ucer 16 is located, thereby reliably preventing the pulsatlon of the fluid in the suction pipe -~
of the pump.
The ~resent embodiment is simple in constructlon and easy in nEnuracture an~ can be applied to hydraulic devices such as pumps having varlous ~inds of capacity irrespective of the design flow a~cunt of the inducer.In Fig. 4 is shown a still further embodimer.t of the invention.
i In the present embodiment, the inducer 16 ls constltuted by at least two ~ -- - stages Or axlal rlow blade parts including, rOr example, a front stage axial -~ rlow blade part 16a and a rear stage axial ~low blade part 16b which ~e ~ ~
dlrrerent ln blade angle~ rrom each other. - -s- The blade angle of the front stage axlal flow blade part 16a located at the rluid suctlcn inlet side is made extremely small whlle the blade angle Or the rear ~tage axial rlow blade part 16b is made large.
In t,hls case, 1~ i8 prerer~ble to define a gap C betw~en the cuter peripheral ' - 7 -., .
, 1041b~34 edge of the front stage axial flow blade part 16a and the insi~e ~lall surface s of the inlet of the pump cha~ber as small as possible.
t In addition, ~n axial distance 1 bet~Jeen the front stage axial flow blade part 16a a~d the rear stage axial flo~ blade part 16b is made equal to 0.05 to G.15 times smaller tl~an a d~ameter D ~f the axial flow b ade of the inducer 16.
In order to easlly define the axial distance 1, the front stage axial flow blade part 16a is made separate from the rear stage axial flow blade part 16b and detach~bly connected to the latteI~.
If the flui~ introduc~d from the front s'~ge axial ~low blade ¦ part 16a into the pump chamber lnlet produces a fluid counter flow between the rear stage axial flQW blade 16b and the maln impeller 14, the present embodiment makes it possible to easily suck the fluld counter flow l~to a space formed between the frcnt stage axial flow blade part 16a and the rear stage axial flow blade part 16b and effect a re-circulation of the ~luid.
¦ As a result, a noise caused by the fluid counter flo~ extended over a wide - region can effectiv~ly be prevented.
Dn Flg. 5 ls shown another embodiment of the invention. In the , pre&ent embodlment, the outer d~ameter D2 ~ the rear stage axial flow blade part 16b is made smaller than the outer diameter Dl or the front stage axial flcw blade part 16a for this purpose of easily sucklng the fluid counter flow --prcduced at the pump chamber inletinto a spece for~ed between the front stage axial flow bl~e part 16a and the rear stage axial flow blade part 16b.
The present embodiment can ~revent the nolse in the same manner as in the j -~
case Or the prevlous ambodinents. -In the present emkodlment, the front stage axial flow blade part 16a ~ay be made lntqgra} with the rear stage axial flow bl~de part l~b.
In addltlon, lt 1~ most prererable to derine a dirference between the outer di~T~ter Dl Or the front sta~e axial flow blade part 16a and the outer dlameter D2 Or the rear stage axial flow blade part 16b by a formula given by , i ~ - 8 -, , : .
.
. ", . . i , . -~ 0 ~ 1 ~ 3 4 Dl - D2 = (-3 to O.l)Dl.
In the present embc~i~ent, the fluid whlch has been introduced into t,he inducer 16 causes the Muid counter flow to re-circulate in the space - form~d between the front sta~e axial flotJ blade part 16a and the rear stage - --axial flow blade part 16b, thereby confining the fluid counter flow into a local fluid cou~ter ~low.
But, the above mentioned measures could not suppress a fluid counter flow produced ln front of the front stage axial flow blade part.
In the invention, in order to suppress .such counter flow, provision is made of a barrier in front of the front stage axial flow blade part 16a.
In Fig. 6 is shown one 6~bodiment of providing such a barrier.
In the present embodiment, a barrier plate 22 is sandwiched between the pump sucticn inlet part 18 of the pump casing 10 and the suction pipe 20.
The present embodiment provides a w~y of simply arranging the barrier plate.
In Fig. 7 ls shown another ~bodiment of providing the barrier. -:
In the present embodi~ent, the front stage axial flow blade part 16a is provlded at its outer peripheral edge with a sleeve 26 having one end secured thereto. Ihe sleeve 26 is extended along a fluid inflow direction, another ~ ;
end of the sleeve 2S being bent inwardly so as to form a barrier 28. ~
In the present embodiment, the wall part of the sleeve 26 which ~ :
.rcrms the barrier 28 is rotated to~ether with the inducer 16, so that it is possible to e~fectively suppress the fluid counter flow by the inside space Or the sleeve 24.
As stated h~reinbefore, the axial flow inducer according to the lnventlon is capable of confining all mcdes of fluid counter M ow produced at the ~ndu~er part into respective local counter streams, and of preventing -the rluld counter flcw from being sprea~ over all fluid flow region, th~reby --oyerating the pump without noise in smooth nEuuler.
The axial flow inducer according to the inventlon has such advantages that lt 18 ~imple in construction, and that it can easily and _ g _ ", ,, ~0~1~34 cheaply manufactured in a mQ5s productlon scale.
or course, the invention is not limited to the above example3 as described and represented. From these examnles other modes and rorms of realization can be foreseen without dep~rtir~ rro~ the spirit of the inventlon.
: , - : -.
,- . . - : .
`:- ` , - : -.. , , ' , : , ' .- '.-:
~: , , .. : , - ' , . .
.
- . ..... ..
., ;, : .
, . . . . .
,, . ~
:~, . . ~ , ,- .
" , , ,,~ -- 10 ,., , : : , ~ : : ; .
, , , - : ~
, . , ,, ,, ,~",~, ,, .",,,, , . , . :, ,.. , . ,, ,,, ;,; ,. ..
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An axial flow inducer for hydraulic devices com-prising a pump casing, a rotary shaft rotatably journaled by said pump casing, a main impeller secured to said rotary shaft, and an inducer coaxially arranged in front of a fluid suction inlet side of said main impeller having at least two axial flow blade parts and a sleeve arranged coaxially with said flow blade parts and extending in the upstream direction from the outer edge of said inducer, said sleeve having one end secured to the outer peripheral edge of said inducer and the opposite end bent inwardly so as to form a barrier.
2. An inducer as claimed in claim 1, wherein a design flow amount of said inducer is about 1.0 to 2 times the design flow amount of said main impeller.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA301,959A CA1053075A (en) | 1975-03-13 | 1978-04-25 | Axial flow inducers for hydraulic devices |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3058775A JPS51105602A (en) | 1975-03-13 | 1975-03-13 | INDEYUUSATSUKI SUIRYOKUSOCHINO SOONBOSHIHOHO |
| JP50030588A JPS51105603A (en) | 1975-03-13 | 1975-03-13 | Jikuryuindeyuusanokairyo |
| JP3058975A JPS51105604A (en) | 1975-03-13 | 1975-03-13 | JIKURYUINDEYUUSANOKAIRYO |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1041834A true CA1041834A (en) | 1978-11-07 |
Family
ID=27287023
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA234,200A Expired CA1041834A (en) | 1975-03-13 | 1975-08-26 | Axial flow inducers for hydraulic devices |
Country Status (9)
| Country | Link |
|---|---|
| BR (1) | BR7507097A (en) |
| CA (1) | CA1041834A (en) |
| CH (1) | CH606804A5 (en) |
| DE (1) | DE2538162C3 (en) |
| FR (1) | FR2303975A1 (en) |
| GB (1) | GB1523893A (en) |
| IT (1) | IT1043574B (en) |
| NL (1) | NL175093C (en) |
| SE (1) | SE418890B (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2558840C2 (en) * | 1975-12-27 | 1983-03-24 | Klein, Schanzlin & Becker Ag, 6710 Frankenthal | Device to reduce cavitation wear |
| US4275988A (en) * | 1978-12-18 | 1981-06-30 | Kalashnikov L F | Axial or worm-type centrifugal impeller pump |
| US4884943A (en) * | 1987-06-25 | 1989-12-05 | A. Ahlstrom Corporation | Method and apparatus for pumping high-consistency fiber suspension |
| US5304033A (en) * | 1992-07-20 | 1994-04-19 | Allied-Signal Inc. | Rotary compressor with stepped cover contour |
| GB2312929B (en) * | 1996-05-07 | 2000-08-23 | Inst Francais Du Petrole | Axial-flow and centrifugal pump system |
| FR2765639B1 (en) * | 1997-07-04 | 2004-11-26 | Europ Propulsion | INDUCER EQUIPMENT FOR PUMP WITH LARGE SUCTION CAPACITY |
| BR9909782A (en) * | 1998-04-22 | 2000-12-19 | Irish & Associates | Flow targeting device, pumping system and efficient flow method of medium to high consistency material slurry |
| US6210105B1 (en) | 1998-11-27 | 2001-04-03 | Irish & Asssociates | Flow directing device for a medium consistency pump |
| FI111023B (en) | 1998-12-30 | 2003-05-15 | Sulzer Pumpen Ag | Method and apparatus for pumping material and rotor used in connection with the apparatus |
| DE19918286A1 (en) * | 1999-04-22 | 2000-10-26 | Ksb Ag | Inducer for centrifugal pump is assembled from individual parts, and has blades fitted into and welded to grooves in inducer hub |
| EP2894343B2 (en) * | 2014-01-12 | 2021-09-01 | Alfa Laval Corporate AB | Self-priming centrifugal pump |
| EP2894342B1 (en) | 2014-01-12 | 2016-12-28 | Alfa Laval Corporate AB | Self-priming centrifugal pump |
| CN112206409B (en) * | 2020-11-10 | 2021-11-30 | 山东大学 | Magnetic suspension mixed flow heart pump |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3299821A (en) | 1964-08-21 | 1967-01-24 | Sundstrand Corp | Pump inducer |
| DE1931527U (en) | 1965-11-26 | 1966-01-27 | Steinebrunner & Co Maschinenfa | DEVICE FOR TRIMMING BRUSHES WITH A CENTRAL FIELD DETACHED FROM THE OUTSIDE FIELD. |
| US3384022A (en) | 1966-04-27 | 1968-05-21 | Ebara Mfg | Centrifugal pump |
-
1975
- 1975-08-20 GB GB34529/75A patent/GB1523893A/en not_active Expired
- 1975-08-22 NL NLAANVRAGE7509973,A patent/NL175093C/en not_active IP Right Cessation
- 1975-08-26 CA CA234,200A patent/CA1041834A/en not_active Expired
- 1975-08-27 DE DE2538162A patent/DE2538162C3/en not_active Expired
- 1975-08-28 FR FR7526549A patent/FR2303975A1/en active Granted
- 1975-09-04 CH CH1146175A patent/CH606804A5/xx not_active IP Right Cessation
- 1975-09-08 SE SE7509953A patent/SE418890B/en not_active IP Right Cessation
- 1975-10-22 IT IT28561/75A patent/IT1043574B/en active
- 1975-10-29 BR BR7507097A patent/BR7507097A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| FR2303975A1 (en) | 1976-10-08 |
| CH606804A5 (en) | 1978-11-15 |
| SE418890B (en) | 1981-06-29 |
| NL175093C (en) | 1984-09-17 |
| NL7509973A (en) | 1976-09-15 |
| IT1043574B (en) | 1980-02-29 |
| BR7507097A (en) | 1976-09-21 |
| DE2538162B2 (en) | 1979-04-26 |
| GB1523893A (en) | 1978-09-06 |
| NL175093B (en) | 1984-04-16 |
| SE7509953L (en) | 1976-09-14 |
| DE2538162A1 (en) | 1976-09-23 |
| DE2538162C3 (en) | 1980-01-03 |
| FR2303975B1 (en) | 1982-07-30 |
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