CA1212335A - Hydraulic multistage turbine of turbodrill - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A hydraulic multistage turbine each stage of which comprises a stator and a rotor having rings with flow channels and hubs carrying the bladings. There are stages wherein the blades of the bladings are made with an angle of curvature of the camber line greater than an angle formed by the tangent to this line at the exit of the bla-ding and the axis of drilling fluid flow. In a stage whe-rein the ring has such blades it is provided with by-pass channels arranged hydraulically parallel to the flow chann of the ring and communicating the space between this ring and an up stream ring with a space between this ring and a downstream ring for discharging part of the drilling fluid from the flow channel.

Description

~2~ 33~

HYDRAULIC ~ULTIS~AGE TURBINE OF ~URBODRI~L
The present invention relates to downhole motors or driving rock destruction drilling tools and more particularly to ~urbodrill hydraulic multistage turbines using, for example, water, clay drilling mud, oil-base drilling mud as a drilling fluid.
A turbine ox the invention is essentially a multitude ox axially alternating stators and rotors secured res-pectivel~ in the housing and on the shalt of a turbodrill.
the stator and rotor arranged in succession in the direc-tion ox flow axis make up a turbine stage.
All stages of a multistage turbine have equal inside and outside diametrical dimensions and an axial dimension.
In each stage the stator and the rotor are provided with a ring and a spacing sleeve.
Any ring has a slow channel and a hub carrying a res-pective bladiLg comprising a plurality of blades equally spaced in the flow channel, and a rim.
The spacing sleeves serve or securing respective rig in the housing and on the shalt of a turbodrill and or enæurlng uniform alternation ox the stator and rotor rings throughout the entire length ox a multistage turbine.
All hydraulic turbines known at present time, including turbodrill multistage turbines are made with the stator and rotor rings sealed along the clearances between the revolving and sta-tionary parts ox the turbine in order to provide a maximum possible prevention of leaks of the -

2~ 3~ S

drilling fluid past the flow chapel with the bladi~.
To this end the clearances in hydraulic turbines, especial-ly the radial clearances, are made as minimum as possible and the value thereon is governed by adaptability to as-sembly.
The known turbodrill turbines have a value ox the radial clearance within the limits oi 0.5 to 1 mm. These turbines are characterized by an increased rotational speed ox the shaft which has an adverse eject on service-ability ox roller-cutter drilling bits.
Besides, due to commensurability ox di;~ensions oi the solid phase contained in the drilling fluid and the radial clearances, a substantial portion of the moment ox force is lost in the known turbines because ox friction in the fluid leading to rapid wear ox turbines and impai-ring their energy characteristic.
no in the prior art i5 a turbodrill m~istage turbine a or example, ERG Patent No.2,942s782), whe-rein in order to increase the torque and e~icienc~ a hub ox an upstream ring prom a pair ox adjacent rings par-tially overlaps the slow channel of a succeeding ring on the side ox its radial clearance.
The given turbine has an increased rotational speed which prevents it from being e~eotively used or driving ro~ler-cutter drilling bits.
In addition, prom 5 to 40% ox the torque (depending on the concentration ox a solid phase) is lost in this

3~35 turbine because oi mechanical friction between the rotors and sta tors along the radial clearances.
It is an object ox the present invention to provide such a turbodrill turbine the construction ox which will ensure a reduced rotational speed or improving the opera-ting conditions or roller-cutter drilling bits and also or minimizing toe losses ox the moment ox force due to friction it the drilling fluid by providing special means to ensure communication between the space at the entry in the ring blading and at the exit therefrom.
he exact nature ox the invention resides in that in a turbodrill multistage turbine each stage ox which comprises a stator and a coaxially disposed rotor each ox which has a spa¢ing sleeve and a ring with a slow channel Por passing the drilling fluid and a hub carr~i~g a blading and a rim arranged in the slow channel, the bla-des oi at least a umber of the rings being made with an ankle ox the camber lint curvature greater Han an acute angle wormed by the tangent to this line a-t the exit of the bladi~g and the axis ox drilling fluid slow, according to -the invention in a s-tage comprising at least one bla-ding with said curva-ture ox the chamber lie the ring wit such bladin~ is made with by-pass channels arranged hydrau~cally parallel to the slow channel ox the ring and co~mu~icating the space betwsen this rink and the upstream rink with the space between this ring and the succeeding downstream ring or discharging part ox the z~

drilling fluid prom the slow channel.
The by-pass channels made hydraulically parallel to the slow channels accommodating the blades with said cur-vature ox the camber line provide for automatic regulation ox the drilling fluid flow rate depending on the mode ox -turbine operation. Due to an increase in ~draulic friction ox the bladi~g with said blades taking plaoe in the period prom the stalling mode to the no-load running condition as the turbine gaits speed, the slow rate oi -the fluid deli-vered to the blading will continuously decrease my virtue ox discharging par of the fluid in the by-pass-channels~
with the result that the turbine rotatlonal speed is redu-cedO
It is most preferable to make the by-pass channels in the form ox an annular space between the rotor spacing sleeve and the stator ring, the ratio ox toe radial di-me~sion ox the annular space to the axial dimension ox the ring being preferably in the range ox 0.2 to 1Ø The lower limit ox said me equal to 0.2 is dictated, accor-ding to the experimental data by the beginning ox an intensive regulation ensuring a substantial decrease in the ro-tational speed. the upper limlt equal to 1.0 is gover-~edLby overall actual diamotrical dimensions ox turbodrill tu~b~ses~
l this case in addition to a decrease in -the turbine rotational speed, the losses ox the Moment ox force caused by rotation it the d~llling fluid containing a solid phase 3~

are reduced and radial wear ox the turbine is practical eliminated.
For this reason it is preferable 5O make the by-pass channels in the Norm of an annular space between the stator spacing sleeve and the ro-tor ring, the ratio ox the radial dimension ox the annular space to the axial dimen-sion ox the ring bel~g preierably selected prom a range ox 0.14 to 0,5~ the lower limit equal to 0.14 is dictated by the dimension of the solid phase amounting to 105 mm which is most characteristic oY drilling fluids. The upper limit equal to 0.5 is conditioned by the tact that its further increase and a respective reduction ox the ro-tational speed due to regulation the iluid slow rate jails to compensate or a rise of the rotational speed because ox decrease it the can diameter ox the rotor slow channel.
In order to rationally utilize the overall diametri-cal dimensions oi a turbine and also to intensify regula-tion ox the flow rat, the by-pass channels may be advan-taæeously made in the body ox the stator and rotor hub.
For preventing the fluid leaks pa the flow channel at a stalllng mode9 i-t is expedient to have the generating line ox the hub suriace worming the slow channel ox a riDg posed upstream from the ring with by-pass charnels on thy e ox the by-pass channel at the exit, inclined prom top to bottom relative to the slow axis. For the same reason, it is preferable that the hub ox a ring 233~
.

disposed upstream prom the ring with by-pass channels partially overlaps its flow charnel on the side ox the by-pass channel.
When the by-pass channel is made it the body oi a hub then in order to prevent the fluid leaks past the slow channel at a stalling mode, it is desirable that the rim oi a ring.disposed upstream prom the ring with the by-pass chan~el~ should partially overlap its slow channel on the side oi the bypass channel.
The.inve~ti:on will now be described in greater de-tail with reverence -to specific embodimen-ts thereo~,-taken in conJunction with the accompanying drawings, wherein:
igs. 1a and 1b illustrate a general view ox a turbo-drill with a bit in the bore hole, comprising a multistage turbine, according to the invention;
Fig. 2 it an exploded view of a turbine stage, accor-ding Jo the invention;
; jig. 3 illustrates an alternative embodiment ox the ~urb~neq according to the inventionS with a b~-pass channel in the Norm ox an annular spaoe between the rim ox a stator and the ~pa¢i~g sleeve ox a rotor;
ig. 4 it a cylindrical section taken on the line n ~Y-IV ox a turbine blading ox Fig. 3 (developed on a plane or clarity);
ig. 5 shows an alternative embodiment oi the turbine, a~c~ ng to the invention, with by-pass channels in the body ox stator and rotor hubs;

, ig. 6 illustrates an alternative embodiment oi the turbine according to the invention, with the generating line ox the hub surface worming -the flow channel on the side ox one by-pass channel disposed downstream prom the rotor, inclined from top to bottom relative to the flow axis, and also with partial overlapping ox the rotor slow chann0l by the stator rip on the side ox another by-pass channel;
Fig. 7 illustrates an alternative embodiment ox the turbine9 according to the invention, with by-pass channels in the Norm of annular spaces between .he rinks ox a stator and the spaciDg sleeve ox a rotor, and the ring ox a rotor and the spaain~ sleeve ox a stator.
A hydraulic multistage t~rbi~ is a working member of a turbodrill (Figs. 1a and qb), wherein a rock destruc-tion tool 3 is convected Jo a shalt 1 and a drill pipe 4 is connected to a housing 2. the shalt 1 is centered in the housing 2 by means ox radial bearings 5 which ensures coaxial rotation ox the shalt 1 relative to an axis A
ox the turbine. Each stage oi the turbine comprises a sta-tor 6 and a rotor 7 jig. 2).
In a turbodrill the system of the stators 6`(Figs.
1a and 1b) i8 iixed against turning relative to the housing 2 ahd the system ox the rotors 7 is mixed against turnip relative to the shalt 1. In each stage the stator 6 (Fig. 3) and the rotor 7 ore provided with respective rings 8 and 9, and also with respective spacing sleeves l and 11, The ring 8 oi the stator 6 and the ring 9 ox the rotor 7 3~

are provided with the respective flow channels 12, 13 and also with hubs 14, 15 carrying bladings 16, 17 with rims 18, 19 thereon.
A straight line S which i's parallel to the axis A of ro-tation and passes in the interior ox the slow chann~:s 12, 13 ma be called an axis ox the flow. An arrow on ,he axis S ox slow indicates the direction oi drilling fluid movementO
From the two rings 8 and 9 (see, for example, jig. 5) the ring is an upstream one relative to the ring 9, while in relation to the ring 8 the rink 9 is a downstream.
During operation ox the turbine the rotation ox the rotors 7 relative to the stators 6 is ensured by the pro-vision ox axial and radial clearances 20, 21 respectively.
The bladings 16, 17 ox the stator 6 and the rotor 7 (Fix. 4) are essentially sets of blades 22, 23 equally spaced in the slow channels 129 13 (Fig. 3).
Profile ox the turbine blades 22, 23 (Fix. 4) is usually characterized by a camber line 24, tangents 25 and 26 to the aamber live 24 at the exit and entry of the bla-ding respeotivel~9 an angle ox curvature ox the chamber line 24 and a angle between the tangent 25 and the axis S ox slow.
Embodiment ox the flow channels 12, 13 (Fig 6) it determined by configuration Or generating lines 27, 28, 2~, 30 ox surfaces of the hubs 14, 15 and the rims 18, 19 r'é'~pectively, forming the slow channels 12, 13 (same reverence numbers denote identical elemen-ts).
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It is to be understood that there may be various em-bodiments ox the turbine. However, irrespective ox a spe-civic embodiment all the turbines, according to the in-vention are made such that in a stage comprising at least one bladin~ 16 (Figs. 3, I) the blades 23 ox which have the angle oC ox curvature ox the camber line 24 treater than the acute angle formed by the tangent 25 to the camber line 24 at the exit of the blading 16 and the axis S of drilling f luid slow, the ring with such a blading is made with by-pass channels 33 arrangsd hydraulically parallel to the flow channel 12 of the ring 8 and commu-nicati~g the space between the ring 8 and-the upstream ring 9 with -the space between the ring 8 and the downstream ring 9 or discharging part ox the drilling fluid prom the slow channel 12 ox the ring 8. The blading 16 is cha-racterized by a enable hydraulia friction which depends on the mode of turbine operation (rotational speed) and is lower at a stalling mode and rises as the tuxbine gains speed .
With the by-pass channels made in the Norm of annular spaces 32 and 33 (jig. 7~ an increase in e~iective~ess ox the turbine operation is attained also duo to.a substan-tial decrease in losses ox the momen-t ox force caused by friction in the drilling fluid containing the solid phase and in wear ox the turbine In addition to the by-pass channels made in the Norm ox the annular spaces 32 and 33, an embodiment ox the turbine shown in jig. 7 is also cha-~%;33~

racterized by the provision ox partial ovelappings o~the flow channel 13 on the side ox the by-pass channel 32 by the hub 14 and also the flow channel 12 on the side ox the by-pass channel 33.by the hub 15.
he experimental investigations have proved that at a ratio of a radial dimension l the annular space 33 between the spacing sleeve 11 ox the rotor 7 and the ring 8 of the stator 6 to an axial dimension h1 the ring 8 being in the range of 0.2 to 1.0, the most favorable con-ditions are provided or regulation of the fluid flow rate it -the stator 6 (Fig. 2)~ As to the rotor 7, such conditions are provided at a ratio ox a radial dimension 2 f the annular space 32 to an axial dimension h2 of the ring 9 being in the range of 0.14 to 0.5.
Absolute values ox d~1 and ~2 in real turbines made according to the invention amount respectively to 2.2-l mm and 1.6 - 5 mm which are substantially greater than the values ox the radial clearances in the known hydraulic turbine.
In order to ra-tio~ally utilize the overall diametrical dimensions of a turbine which is especially essential for turbines ox small diameters and also to i~tensiiy regula-ton, it it preferable to make the b~-pass charnels 34 and 31 (Fig. 5) in the body of the hub 14 ox the stator 6 and the hub 15 of the rotor 7.
It is desirable that a generating live, for example 27 (jig. 6), ox the suriace of the hub 14 forming the flow channel 12 oi the ring 8 arranged upstream from 3~

the ring 9 with the by-pass channels 31 and 32 be inclined from top to bottom on the side ox the by-pass channel ~2 at the exit in relation to the axis S of slow, The slow channels 12, 13 of the rings 8, 9 made with such an incli-nation of the generating lines 27, 28, 29, 30 of the sur-race minimizes the leaks ox the drilling fluid past the flow channels 13, ~2 at a stalling mode determi~i~g the load pick-up characteristics ox the turbine.
For the same reason, it is preferable that the hub 14 and/or 15 (Figs. 6, 7) and the ring 18, 19 ox toe ring 8, 9 arranged upstream prom the ring 9, 8 with by-pass charnels 32, 33, 31, 34 respectively should partially over-lap the ilow channel 13, 21 on the side ox the by-pass channel 32, 33, 31, 34 respecti~el~.
A hydraulic multistage turbine ox the invention ope-rates in the hollowing way.
rom the surface the mud pumps deliver the drilling fluid through the drill pipe 4 figs. 1a and 1b) to the turb~drill. At a stalling mode the drilling fluid it the amount delivered by the pump prom the surface passes out ox the flow channel l ox- the rotor 7 (Fig. 3) with a preset deviation of the slow acquired due to interaction with the blading 17. Further the fluid passes in the ilow channel 12 oi the stator 6. As at this mode ox operation the hydraulic friction ox the blading 16 is at a minimum the drilling fluid enters in the pull volume the slow channel 12 ox the stator 6, wherein it acquire a respec-~12-tive deviation, Interaction of the drilling fluid withthe bladings 17 and 16 in the pull volume results in providing a maximum moment oi force ox the turbine.
As the turbine gain speed the hydraulic iriction ox the blading 16 increases due to which part of the drilling fluid (up to 30~0 at a no-load running condition) leaving the slow channel 13 goes in the by-pass channel 3~ past the blading 16. the remaining part of the dril-ling fluid which passed through the blading 16 has a lower speed which provides a respective decrease in the rota-tional speed I the tuxbine. Thus the flow rate ox the dril-fig fluid passing through the bladin~s is regulated inside the turbine proper which brings about the required reduction in the rotational speed, with the moment oY
force beins retained.
Due to reduction in the rotational speed up to 14~-200 rpm in an optimal altsrnative embodiment), the use ox the turbine of the invention makes it possible to improve durability ox the bits by 1.5-4.0 times anc consequently to increase the iootage per bit by 1O3-3.
times when compared with the known turbinesO Greater figures are provided by the use ox drilling bits with oil-~illed sealed bearings.
In an alternative embodiment ox the turbine shown in jig. 7, there is also provided a substantial decrease ~nLthe unfavorable lose ox the moment ox force caused by Iriction ox the rotor 7 in the drilling iluid contai-ning the solid phase, with the result that durabiht~
of toe turbine is upgraded.

Claims (8)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. In a turbodrill provided with a rock destruction tool for drilling wells, a hydraulic turbine for driving said rock destruction tool under the action of a drilling fluid, comprising:
a plurality of identical stages each of which is formed by one stator and one rotor;
said stator of one stage;
a spacing sleeve of said stator;
a ring of said stator incorporating:
a hub;
a blading formed by a multitude of blades equally spaced on the inside of said hub of the stator ring;
a rim secured to said blades at the tips thereof away from said hub, and a flow channel for passing the drilling fluid arranged between said hub and said rim, and accommodating said blading;
blades of said blading which, at least in a number of said stator rings from said plurality of stages, are made with an angle of curvature of the camber line being greater than an acute angle formed by the tangent to this line at the exit of the blading and the axis of drilling fluid flow:
said rotor of one stage arranged coaxially with said stator;
a spacing sleeve of said rotor;
a ring of said rotor incorporating:
a hub;
a blading formed by a multitude of blades equally spaced along the periphery of said hub of the rotor ring;
a rim encompassing said blades at the tips thereof away from said hub, and a flow channel for passing the drilling fluid arranged between said hub and said rim, and accommodating said blading;

blades of said blading of the rotor ring which, at least in a number of said rotor rings from said plurality of the stages, are made with an angle of curvature of the camber line being greater than an acute angle formed by the tangent to this line at the exit of the blading and the axis of drilling fluid flow;
by-pass channels made at least in one of said rings of the stator or rotor from said plurality of the stages having said blades of the blading with the above-mentioned curvature of the camber line, said by-pass channels being arranged hydraulically parallel to said flow channel of the ring and serving to communicate a space between this ring and an up stream ring with a space between this ring and a downstream ring for discharging part of the drilling fluid from said flow channel of the ring said by-pass channels in the stator having a radial dimension exceeding 2.2 mm, and in the rotor 1.6 mm.

2. A hydraulic turbine of a turbodrill as claimed in claim 1 wherein said by-pass channels are made in the form of an annular space between said spacing sleeve of the rotor and said ring of the stator, the radial dimension of said space being of a value lying in the range of from 2.2 to 10 mm.

3. A hydraulic turbine of a turbodrill as claimed in claim 2 wherein said by-pass channels are made in the form of an annular space between said spacing sleeve of the stator and said ring of the rotor, the radial dimension of said space being of a value lying in the range of from 1.6 to 5 mm.

4. A hydraulic turbine of a turbodrill as claimed in Claim 2 wherein said by-pass channels are made in the body of said hub of the stator.

5. A hydraulic turbine of a turbodrill as claimed in Claim 3 wherein said by-pass channels are made in the body of said hub of the rotor.

6. A hydraulic turbine of a turbodrill as claimed in Claim 1 wherein the generating line of a surface for-ming said flow channel of the ring disposed upstream from the ring with said by-pass channels is inclined, on the side of said by-pass channel at the exit, from top to bottom relative to the flow axis.

7. A hydraulic turbine of a turbodrill as claimed in Claim 1 wherein said hub of the ring disposed upstream from the ring with said by-pass channels partially over-laps its flow channel on the side of said by-pass channel.

8. A hydraulic turbine of a turbodrill as claimed in Claim 1 wherein said rim of the ring disposed upstream from the ring with said by-pass channels partially over-laps its flow channel on the side of said by-pass channel.