CA1260454A - Annular air-hammer apparatus for drilling holes - Google Patents
Annular air-hammer apparatus for drilling holesInfo
- Publication number
- CA1260454A CA1260454A CA000516315A CA516315A CA1260454A CA 1260454 A CA1260454 A CA 1260454A CA 000516315 A CA000516315 A CA 000516315A CA 516315 A CA516315 A CA 516315A CA 1260454 A CA1260454 A CA 1260454A
- Authority
- CA
- Canada
- Prior art keywords
- hammer
- idle
- case
- chips
- stroke
- 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
- 238000005553 drilling Methods 0.000 title claims abstract description 19
- 238000005520 cutting process Methods 0.000 claims abstract description 14
- 230000005465 channeling Effects 0.000 claims abstract description 7
- 239000012530 fluid Substances 0.000 claims description 8
- 239000003795 chemical substances by application Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000011435 rock Substances 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 101150111329 ACE-1 gene Proteins 0.000 description 1
- 101150039033 Eci2 gene Proteins 0.000 description 1
- 208000036366 Sensation of pressure Diseases 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 230000002301 combined effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 239000011236 particulate material Substances 0.000 description 1
- 229920000136 polysorbate Polymers 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 238000010257 thawing Methods 0.000 description 1
- 230000003245 working effect Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
- E21B21/12—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor using drilling pipes with plural fluid passages, e.g. closed circulation systems
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B4/00—Drives for drilling, used in the borehole
- E21B4/06—Down-hole impacting means, e.g. hammers
- E21B4/14—Fluid operated hammers
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Earth Drilling (AREA)
- Drilling And Exploitation, And Mining Machines And Methods (AREA)
Abstract
ANNULAR AIR-HAMMER APPARATUS FOR DRILLING HOLES
Abstract An annular air-hammer apparatus for drilling holes incorporates a hollow cylindrical case with a stepped bore which has inlet and outlet ports.
A rock-cutting tool with an axial opening is fit-ted to the case at the forward end thereof. A chips-receiving sleeve and a stepped ring-shaped hammer are located inside the case, whereby the hammer forms a working-stroke chamber with the case and an idle-stroke chamber with the case, the rock-cut-ting tool and the chips-receiving sleeve. The chips-receiving sleeve has a cylindrical protuberance at its upper end which interacts with the hammer when this is in its topmost position. A channeling means is provided in the idle-stroke chamber at that side thereof which faces the upper end face or the hammer.
Abstract An annular air-hammer apparatus for drilling holes incorporates a hollow cylindrical case with a stepped bore which has inlet and outlet ports.
A rock-cutting tool with an axial opening is fit-ted to the case at the forward end thereof. A chips-receiving sleeve and a stepped ring-shaped hammer are located inside the case, whereby the hammer forms a working-stroke chamber with the case and an idle-stroke chamber with the case, the rock-cut-ting tool and the chips-receiving sleeve. The chips-receiving sleeve has a cylindrical protuberance at its upper end which interacts with the hammer when this is in its topmost position. A channeling means is provided in the idle-stroke chamber at that side thereof which faces the upper end face or the hammer.
Description
~0454
- 2 -UnNULAR AIR-H~MMER APPARA~US ~OR DRILLING HOLES
Industrial ~pplication The invention relate~ to air-h~mmer appara-tus employed for drilling hole~ in mining, con-struction and pro~pecting which use a conce~tric3tring and transport the rock broken up at the bot-tom of the hole through the central pipe in the form of ¢ores and chips to the surface b~ means of the retur~ flow oi the agent p~o~iding motive power. More specifically~ the in~ention i3 concern-ed with snnular air-hammer apparatus for drilling holes~
The invention may be of utility in drilling holes for ~arious applications such as searching for mineral deposlt~ in permafrost regions and on the Continental Shelf~ blasting rock in open pits and sinking pile foundation~ at construction sites.
~a¢kground of the Inve~tion Specifi¢ conditions of ~ir-hammer drilling ; 20 render the dust-collecting equipment commonly pro-vided at the wellhead ineffective as a meQns of maintaining the du~t content of the atmosphere at the work~ng place within the limits speciried by hygisnic~. ~or dodu~bing~ an aerated solution can bo fed into the hole. However9 as fsr as the , :
:. . .
,~
. . .
~54 drilling in permafro~t i8 concerned, this ~ethod i~ inapplicable: the wall of hole may t}~w and cs~e or, in the case of pro~pecting, a mineral 30ught may displace from a higher l~vel of a hole to a lower one ~o that the factual geological data msy become mi~leading~ ~herefore, air-hammer dril-ling find~ limited application in permafro~t re-gion~-A radical 301ution to the problem o~ thawing and caving of holes, dedu~ting the drillman~s work-ing place and ac~uiring trust-worthy geolo~ical information can be obtained by employing annular air-hammer drilling apparatus ~hich dispose of the chips via the central pipe of concentrio string with a constant cro~s-secltional area connected to a duet-colleoting equipment~ e.g. a cyclone, at the ~urface. Since the agent providing motive power i8 i~olated fro~ direct contact with the wall of hole and the velocity of the chips-laden return flow of the agent through the central pipe i8 con-3tant, the difficulties referred to above are in-existent in thi~ ca~e.
~ here i~ ~nown an annular air-hammer drilling apparatue (of. Patent~chrift Nr. 2854461 Bundes-republlc Deut¢hland, IPC E21C 3/24~ 1978) termedperforator which incorporate~ a rock-cutting tool .
, .
~45~ A
and a~ a~nular hammer reciprocating in a ¢ylind-rical case with air-dl~tributing port~ and ~trik-ing again~t the tool. ~he perforator i3 provided with a non-return val~e and an internal chips re-ceiver, ~nd i9 employed with a concentric 8tring-The known p~rforator and ~imilar apparatusfor core drilling rsly on a combined effect of an impact against~ and a rotary motion of, the tool.
~hey are pro~ided in the form oi air-operated down-the-hole units in which air reaches the hammer via the annular gap in the concentric 3tring and the non-return ~alve. Spent air leaves into the bottom-hole region.
~he known annulsr air-hammer drilling appara-tus has an intrioate ~ystem of distributing air, and many parts thereof are made of light-gauge ~hapes. Therefore, it lack~ operational reliabill-ty a~d tails to iind a wide-~pread industrial ap-plicatio~ ~o far.
Also known i~ an annular air-hammer drilling apparatus (cf. U~R InYento~'s Certi~icate No.n33398, IPC E21C 3/24, 1985) a hollo~ ¢~lindrical ¢ase whereof is fitted ~t the front end with a ro¢k-cut-tin~ tool ha~lng blo~ off ports and contains a chips recei~er ~nd a stepped annular hammer capable , ~
:i J"~
. ... .
i~2Ç~45~
of reciprocating back and ~orth. ~he hammer i8 ~itted concentrically with the case and i~teract~
with the outside surfsce of 8 ~tepped sleev~
which ha~ in~et and outlet ports and i~ fixed in the oa~e bore. I~ reciprocatingj the hammer forms an idle-stroke chamber with the case and a working-stroke chsmber with the ~tepped sleeYe. Another sleeve interposed bet~een 8 ~tep of the stepped slee~e oi ~ larger diameter and the hammer with provision ior axial displacement hs~ an annular recess st its midlength fitting whereinto i~ a pro~ecti~g stop of the h~mmer.
~he abo~e features of desien permit control Or the time interval during which air is being ad- -mitted into the working-stroke chamber and, conse-quently, inc~ease the impact *oroe Or the appara-tus. But in the kno~n apparatus the outflow oi ~pent air from the worklng-~troke chamber is pa~sed into the chips re¢eiver through the ports oi the stepped 31ee~e which are located at some distance from the bottom hole. Only a ~mall iraction oi the air ~about 20%) escapes into the bottom hole space ~ia the blow oif porte oi the rock-cuttln~ tool, by-pa~oing the hammer. Thereiore~ the rate of advance of the material iorced up the chips receiver in the i260~54 ~orm o~ disintegrated core and chips, as broken oif at the bottom hole, i~ ~low until the outlet por~s are reached where a combined current of air accelerate~ th~ material to the ~peci~ied velocity of lifting up th~ chip~ recei~er. Such a pattern of air flow may bring about plugging up of the rock-cutting tool and the chips receiver at it~ lo~er ~nd by the material. Not excluded i8 al~o an ingress of particulate material into the working-stroke chamber through the ports of the air-distributing ~leeve whlch ma~ lead to an abrasiYe wear of the rubbing ~urfaoes or even to the sizing of the ham-mer in the ca~e.
A plugging up oi the core receiver~ may cause the baokpre~sure in the ~utlet line oi the known annular air-hammer apparatus to ri~e greatly, de-~tabilizing the operation oi the hammer throughout a cycle. It~ frequenoy and ~mpaot foroe may devi-ate from the design values.
All ~n all, these faotors hs~e an ad~erse e~-fect on the reliability and efficiency of the known an~ular air-hammer apparatus.
; Summary of the Invention It is an ob~oct of the invention to improve i 25 the periormanoe (i.e. inorease the frequenoy and impaot force of stro~es) of the apparatus.
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i2604S~
.~nother object of the invention iB to increase the operational reliability of the apparatu~.
These and other ob~ects are realized by pro~id-ing an annular sir-hammer apparatus for drilling holes compri~ing a hollow cylindrical case with a stepped bore; inlet port3 in a ~tep o~ the bore of a ~maller diameter and outlet ports in a step o~ the bore of a larger diameter; a rock-cutting tool attached to the forward end of the case and provided with a~ axial openlng; a chip~-receiving sleeve and a stepped ring-~haped hammer which are both located in the bore o~ the case; whereby the hammer i8 fitted ¢onoentrically with the ca~e with pro~ision ~or reciprocating ba¢k and iorth 90 as to form a working-~troke chamber with the ca~e and an idle-stroke chamber with the csae, the rock-cutting tool and the chips-receiving slee~e; the two chambers alternstely oommunicating ~ia the in-let port~ with a line ~or ~eeding a compres~ed ga~e-ou8 fluid and Yia the outlet ports with the bottomhole~ wherein according to the invention the ¢hips-recei~ing slee~e has a cylindrical protuberance .
Bt its upper end which interaots with the hammer, when thi~ come~ into its topmo~t position, and separates the idle-stroke chamber into an upper ~260~4 ~pace and a lower space at the ~ame time~ whereby a channeling means serving to conneot the working-atroke chamber to the upper space o~ the idle-stroke chamber at regular inter~als i~ proYided ln the idle-~troke chamber at that ~ide thereo~ which faces th~ upper end face o~ the hammer.
It will be noted that in the disclosed appa-ratus th~ hammer i8 accelerated during the idle 3troke, for the idle-stroke chamber i~ ~eparated into an upper and a lower space and compressed air is expelled from that space where it~ pre~ence would ~low down the progres~ of the hammer.
The acceleration o~ the hammer on the working ~troke i8 higher than in the Xnown apparatus. ~he hammer ~ aoted upon by alresultant force due to the pre~ure Or compressed air in the worXing-~troke chamber, which i8 connected to the compre~sed air line at regular intervale, and the pre~ure in the upper space o~ the idle-stroke chamber which is formed by the cylindrical protuberance o~ the chip8-recei~ing slee~e and communicates with the ~orking-stroke chamber~ The two forces acting on the hsmmer co~ncide i~ dire¢tion snd it~ ~peed on the working ~troko there~oro in¢rea~es.
Summing up, two ac¢eleratione of the hammer occur in the discloeed apparatus, on the idle ~troke ~,.
~6~454 3nd on the working one. ~here~ore, the frequency and impact foxce of the strokes i~crea~e~ there.
It i8 expedient that the channeling means i9 pro~ided in the ~orm of at lea~t a single lo~gi-tudinal groove which e~tend~ between the inlet portsof the case through a full-length ~troke of the hammer.
Thi3 plan permit~ an optimum perfor~ance of the ring-shaped hammer to be achieved in spite of a limited radial extent of its working ~uriace. An optimum relation#hip between the cross-se¢tional area of the chann~ling mean~ and the volume of the chambers which is established in thi~ case pro~ides ~or a minimum con~umption of compressed air~ ensur-in8 economical operation ~f the hammer unit andthe apparatus as a whole.
Briei~ Description of the Drawing~
A preferred embodiment of the invention will now be described with reference to the accompany-ing drawing~ in which Pig. 1 i~ a schematic cross-~ectional eleva-tion of the annular air-hammer apparatus for dril-; ling hole~ according to the in~ention, in a po~i-tion when the hammer strike~ again~t the rock-cut-ting tool~
-- 10 _ ~ ig. 2 i~ a ~chematic cro~s-~ectional eleva-tion o~ the annular air-hammer apparatu~ for dril-ling holes according to the in~ention, in a posi-t~on when the hammer i8 on the idle stroke and ar-rive~ at it~ topmo~t ~tation;
Fig. 3 i~ a as¢tion on line III-III of Fig. 1-Detailed Description of the I~Yention Referring to Fig~. 1 and 2, the annular air-hammer apparatus for drilling holes incorporates ~ a hollow ¢ylindrical ca~e 1 with a stepped bore.
A step 2 Or ~ smaller diameter locatad at the top of the case 1 i~ pro~ided with inlet ports 3 ad-mitted wherethrough irom a line i9 a compre~ed ga~eous fluid~i and a step 4 of a larger diameter 15 whioh faces the bottom holle is pro~ided with outlet ports 5. The case 1 is rigidly attached at its top to an external pipe 6 oi a concentric string 7.
rock-cutting tool 8 with an axial chips-receiv-ing opening 9 and blow ofi passages 10 i~ fitted 20 to the step 4 at the lower end oi the case 1 with pro~ieion for a~ial displacement. Contained in the bore of ths stepped ca~e 1 there are a stati¢ chips-receiving clee~e 11 and a ~teppod ring-shaped ham-mer 12 capablo of re¢iprocating ba¢k and forth 25 ¢on¢entri¢slly ~ith the ¢ace 1 ~o ae to form a ,, : , , .
i260~i4 working-stroke chamber 13 with the ca~e 1 and a~
ldle-~troke chamber 14 with the ca~e 1~ the rock-cutting tool 8 ~nd the chips-recei~ing ~leeve 11 The chambers 13 and 14 alternately communicate with the bottom hole 15 via the outlet ports ~.
The lower end 16 of the chips-recei~ing ~leeve 11 ~it~ into the axial chipa-receiving opening 9 of the rock-cutting tool 8~ and the upper end 17 of the chip~-receiving ~lee~e 11 i8 linked to the internal pipe 18 of ~e concentr~c string 7. A
cylindri¢al protuberance 19 of the ohips-recei~-ing slee~e 11 provided at the upper end thereof interacts with the bore 20 of the hammer 12 when thi~ arrives into its topmost position ~Pig. 2) ~o a~ to separate the idle-stroke chamber 14 into an upper space 21 and a lower space 22 which com-municates with eaoh other through an annular pas-sage 23. ~he idle-etroke chamber 14 18 pro~ided with a channeling means ln the form o~ a single lo~gitudinal groove 25 lo¢ated in the cyl~ndrical bore 24 of the step 2 o~ the case 1 between the in-let ports 3 (Figo 3). Alternati~ely, a plural~ty Or su¢h grooves 25 ¢an be provided for.
A ahell 26 ser~es to protect the apparatus, e.g- it~ work~n4-etroke chsmber 13, against an .. ..
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~604S4 lngres~ o~ chips. A pac~er 27 pro~ided at the bottom of the ~hell 26 i901ate9 the bottom hole 15 from L,he shell-borehole annulu~ 28 in order to induce a flow of spent air from the bottom hole 15 into the bore 29 o~ the chip~-receiving sleeve 11.
The fact that in the ambodiment of the inven-tion disclosed hereinabove the cylindrical protu-berance 19 o$ the chipa-receiving sleeve 11 at the upper end thereof interacts with the bore 20 of the hammer 12 and separate~ the upper ~pace 21 o~ the idle-~troke chamber 14 from the lower ~pace 22 thereof at regular interval~ and that the chan-neling means i8 provided in the idle-stroke cham-ber 14 at the side thereof faci~g the upper end face of the hammer 12 to bonnect this chamber to the compressed air line through the working-atroke chamber 13 at regular intervals when the hammer 12 arrive~ into its topmost position ensures an ef-fecti~e utilization of the area of the upper end ZO iace 30 of the hammer 12 with the result that the force~ acting thereupon during every operati~g cycle sugment and the performance of the apparatu~ (i.e.
the frequency and force of strokes) impro~es and its reliability in¢rea~es.
' 12604~4 In operation, the compressed air fed over the annular space between the internal pipe 18 (Fig. 1) and the external pipe 6 of the string 7 is admitted into the idle-stroke chamber 14 through the inlet ports 3, whereby the working-stroke chamber 13 is connected to the bore 29 of the chips-receiving sleeve 11 via the open outlet ports 5, the blow off passages 10 of the rock-cutting tool 8 and the bottom hole 15. The air admitted into the idle-stroke chamber 14 acts on both the upper and lower end faces 30 and 31, respectively, of the hammer 12.
The resulting forces oppose one another in direc-tion. However, the area of the lower end fase 31 is larger than that of the upper end face 30, and ; the hammer 12 starts moving upwards (Fig. 1), beginning an idle-stroke. As ~oon as collars 32 and 33 of the hammer 12 overlap the outlet ports 5 and the inlet ports 3, respectively, the flow of air ~ into the idle-stroke chamber 14 is interrupted. In - continuing on the idle stroke, the hammer reaches the cylindrical protuberance 19 of the chips-receiving sleeve 11 which closes the annular passage 23, separating thus the upper space 21 of the idle-stroke chamber 14 from the lower space 22 thereof. At the same time, the hammer 12 uncovers the longitudinal grooves 25 which connect the D
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12~0454 upper ~pace 21 of the idle-stroke chamber 14 to the working-~troke chamber 13. The air contained in the upper ~pace 21 o~ ~ idle-~troke chamber 14 escap~ into the working-stroke chamber 13, and the pre~sure in the two chambers 13 and 14 is equalized. But ~ince the volume of the working-stroke chamber 13 exceeds that of the idle-~troke chamber 14 three- to sixfold whereas the volume of the up-per space 21 oi the idle-~troke chnmber 14 i~ be-10 tween only 1/6 and 1J10 of the volume of the work-ing-stroke chamber 13, the equalized pres~ure in the two chamb~rs i8 slightly abo~e the atmo~pheric ~ressure and greatly le~s than the pressure in the compreesed air mains. The air pressure applied 15 to the upper end faoe 30 df the hammer 12 and hampering its progress decreases whereas the pres-sure which the air in the lower ~pace 22 of the ; idle-stroke chamber 14 exerts on the lower.~nd face 31 o~ the hammer 12 rem~ins unchanged. The 20 re~ultin~ pres~ure difference accelerate~ the hammer 12, e~abling it to complete the idle ~troke within a shorter time inter~al.
Purther upward progreos oi the hammer 12 oon-nects the outlet port~ 5 to the lower ~pace 22 25 Or the idle-stroke chamber 14 and the inlet port~ 3 ,, .
to the working-stroke chamber 13. The air contain-ed in the lower ~pace 22 of the idle-~troke cham-ber 14 e~capes, and compressed air is'admitted into the working-~troke chamber 13 and.hen¢e,into the upper ~psce 21'of the idle-stroke chamber 14 via the groove~ 24.
The air pressure ~et up in the two chambers and spplied to the upper end ~a¢e 30 of the hammer 12 and the annular area ~ormed due to the dif~e-rence between the diameter~ o~ the large-diameter collar 32 and the ~mall-diameter collar 33 causes the hammer 12 to stop a~d rever~e the direotion of its travel, 3tarting a working ~troke down~ards (Pig. 2)- As the ¢ollar~ 32 and 33 oi the hammer ~5 12 overlap the inlet ports 3 and the outlet ports 5, the source o~ the motive power of the hammer 12 i~ the energy of the a~r expanding in the working-~tro~e chamber 13 and the upper space 21 of the idle-~troke chamber 14. Continuing it~ downward travel, the hammer 12 disconnect~ the working-stroke ohamber 13 from,the upper space 21 o~ the idle-stroke chamber 14 due to its collar 32 which overlaps the longitudinal grooves 24 and connects the Uppor space 21 to the lower space 22.of the ' Z5 idle-stroke chamber ~4 through the uncovered i, iZ60454 -- 16 _ annuiar pa~age 23. The pres~ure in the two ~paces 21 and 22 of the idle-stroka chamber 14 equalizes-At the same time~ the inlet ports 3 are connected to the idle-~troke chamber 14 and the outlet ports 5 to the working-~troke chamber 13. The ~ir contain-ed in the working-stroke chs,mber 13 e~cspes and compres~ed air enters the idle-stroke chamb~r 14.
The hammer 12 strikes against the rock-cuttin~
tool 8, and the rock broken of~ i~ carried to the surface by ~ current of spent air ~ia the annular chips-recei~ing opening 9 in the rock-cutting tool 8, the bore 29 of the chip3-recei~ing sleeve 11 and the internal pipe 18 of the concentric ~tring 7.
The regular ~epsrations of the idle-stroke chamber 14 into two spaceb followed by the connec-tlons of its upper space 21 to the working-~troke chamber 13 are the factors whi¢h augment the forc-es applied to the hammer 12 in operation. The area of the hPmmer acting whereupon i~ compres~ed air i~ expanded both during the work~ng and idle strokes.
Th~ speed of the hammer 12 increases~ and the pe-riods of effecting the idle and working strokes sre shortened.
~he disclosed apparatus compares fa~ourably ~, 25 with the known annular air-hammer apparatus ~or .
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~O~S4 drilling holes, ~eatu~ing a 1 .5-fold increaee in the fre quency of stroke~, high impact ~tre~lgth and operstional reliability.
, . . .
Industrial ~pplication The invention relate~ to air-h~mmer appara-tus employed for drilling hole~ in mining, con-struction and pro~pecting which use a conce~tric3tring and transport the rock broken up at the bot-tom of the hole through the central pipe in the form of ¢ores and chips to the surface b~ means of the retur~ flow oi the agent p~o~iding motive power. More specifically~ the in~ention i3 concern-ed with snnular air-hammer apparatus for drilling holes~
The invention may be of utility in drilling holes for ~arious applications such as searching for mineral deposlt~ in permafrost regions and on the Continental Shelf~ blasting rock in open pits and sinking pile foundation~ at construction sites.
~a¢kground of the Inve~tion Specifi¢ conditions of ~ir-hammer drilling ; 20 render the dust-collecting equipment commonly pro-vided at the wellhead ineffective as a meQns of maintaining the du~t content of the atmosphere at the work~ng place within the limits speciried by hygisnic~. ~or dodu~bing~ an aerated solution can bo fed into the hole. However9 as fsr as the , :
:. . .
,~
. . .
~54 drilling in permafro~t i8 concerned, this ~ethod i~ inapplicable: the wall of hole may t}~w and cs~e or, in the case of pro~pecting, a mineral 30ught may displace from a higher l~vel of a hole to a lower one ~o that the factual geological data msy become mi~leading~ ~herefore, air-hammer dril-ling find~ limited application in permafro~t re-gion~-A radical 301ution to the problem o~ thawing and caving of holes, dedu~ting the drillman~s work-ing place and ac~uiring trust-worthy geolo~ical information can be obtained by employing annular air-hammer drilling apparatus ~hich dispose of the chips via the central pipe of concentrio string with a constant cro~s-secltional area connected to a duet-colleoting equipment~ e.g. a cyclone, at the ~urface. Since the agent providing motive power i8 i~olated fro~ direct contact with the wall of hole and the velocity of the chips-laden return flow of the agent through the central pipe i8 con-3tant, the difficulties referred to above are in-existent in thi~ ca~e.
~ here i~ ~nown an annular air-hammer drilling apparatue (of. Patent~chrift Nr. 2854461 Bundes-republlc Deut¢hland, IPC E21C 3/24~ 1978) termedperforator which incorporate~ a rock-cutting tool .
, .
~45~ A
and a~ a~nular hammer reciprocating in a ¢ylind-rical case with air-dl~tributing port~ and ~trik-ing again~t the tool. ~he perforator i3 provided with a non-return val~e and an internal chips re-ceiver, ~nd i9 employed with a concentric 8tring-The known p~rforator and ~imilar apparatusfor core drilling rsly on a combined effect of an impact against~ and a rotary motion of, the tool.
~hey are pro~ided in the form oi air-operated down-the-hole units in which air reaches the hammer via the annular gap in the concentric 3tring and the non-return ~alve. Spent air leaves into the bottom-hole region.
~he known annulsr air-hammer drilling appara-tus has an intrioate ~ystem of distributing air, and many parts thereof are made of light-gauge ~hapes. Therefore, it lack~ operational reliabill-ty a~d tails to iind a wide-~pread industrial ap-plicatio~ ~o far.
Also known i~ an annular air-hammer drilling apparatus (cf. U~R InYento~'s Certi~icate No.n33398, IPC E21C 3/24, 1985) a hollo~ ¢~lindrical ¢ase whereof is fitted ~t the front end with a ro¢k-cut-tin~ tool ha~lng blo~ off ports and contains a chips recei~er ~nd a stepped annular hammer capable , ~
:i J"~
. ... .
i~2Ç~45~
of reciprocating back and ~orth. ~he hammer i8 ~itted concentrically with the case and i~teract~
with the outside surfsce of 8 ~tepped sleev~
which ha~ in~et and outlet ports and i~ fixed in the oa~e bore. I~ reciprocatingj the hammer forms an idle-stroke chamber with the case and a working-stroke chsmber with the ~tepped sleeYe. Another sleeve interposed bet~een 8 ~tep of the stepped slee~e oi ~ larger diameter and the hammer with provision ior axial displacement hs~ an annular recess st its midlength fitting whereinto i~ a pro~ecti~g stop of the h~mmer.
~he abo~e features of desien permit control Or the time interval during which air is being ad- -mitted into the working-stroke chamber and, conse-quently, inc~ease the impact *oroe Or the appara-tus. But in the kno~n apparatus the outflow oi ~pent air from the worklng-~troke chamber is pa~sed into the chips re¢eiver through the ports oi the stepped 31ee~e which are located at some distance from the bottom hole. Only a ~mall iraction oi the air ~about 20%) escapes into the bottom hole space ~ia the blow oif porte oi the rock-cuttln~ tool, by-pa~oing the hammer. Thereiore~ the rate of advance of the material iorced up the chips receiver in the i260~54 ~orm o~ disintegrated core and chips, as broken oif at the bottom hole, i~ ~low until the outlet por~s are reached where a combined current of air accelerate~ th~ material to the ~peci~ied velocity of lifting up th~ chip~ recei~er. Such a pattern of air flow may bring about plugging up of the rock-cutting tool and the chips receiver at it~ lo~er ~nd by the material. Not excluded i8 al~o an ingress of particulate material into the working-stroke chamber through the ports of the air-distributing ~leeve whlch ma~ lead to an abrasiYe wear of the rubbing ~urfaoes or even to the sizing of the ham-mer in the ca~e.
A plugging up oi the core receiver~ may cause the baokpre~sure in the ~utlet line oi the known annular air-hammer apparatus to ri~e greatly, de-~tabilizing the operation oi the hammer throughout a cycle. It~ frequenoy and ~mpaot foroe may devi-ate from the design values.
All ~n all, these faotors hs~e an ad~erse e~-fect on the reliability and efficiency of the known an~ular air-hammer apparatus.
; Summary of the Invention It is an ob~oct of the invention to improve i 25 the periormanoe (i.e. inorease the frequenoy and impaot force of stro~es) of the apparatus.
....
7 ~
;.......
, . : ~,.. ,; .:
i2604S~
.~nother object of the invention iB to increase the operational reliability of the apparatu~.
These and other ob~ects are realized by pro~id-ing an annular sir-hammer apparatus for drilling holes compri~ing a hollow cylindrical case with a stepped bore; inlet port3 in a ~tep o~ the bore of a ~maller diameter and outlet ports in a step o~ the bore of a larger diameter; a rock-cutting tool attached to the forward end of the case and provided with a~ axial openlng; a chip~-receiving sleeve and a stepped ring-~haped hammer which are both located in the bore o~ the case; whereby the hammer i8 fitted ¢onoentrically with the ca~e with pro~ision ~or reciprocating ba¢k and iorth 90 as to form a working-~troke chamber with the ca~e and an idle-stroke chamber with the csae, the rock-cutting tool and the chips-receiving slee~e; the two chambers alternstely oommunicating ~ia the in-let port~ with a line ~or ~eeding a compres~ed ga~e-ou8 fluid and Yia the outlet ports with the bottomhole~ wherein according to the invention the ¢hips-recei~ing slee~e has a cylindrical protuberance .
Bt its upper end which interaots with the hammer, when thi~ come~ into its topmo~t position, and separates the idle-stroke chamber into an upper ~260~4 ~pace and a lower space at the ~ame time~ whereby a channeling means serving to conneot the working-atroke chamber to the upper space o~ the idle-stroke chamber at regular inter~als i~ proYided ln the idle-~troke chamber at that ~ide thereo~ which faces th~ upper end face o~ the hammer.
It will be noted that in the disclosed appa-ratus th~ hammer i8 accelerated during the idle 3troke, for the idle-stroke chamber i~ ~eparated into an upper and a lower space and compressed air is expelled from that space where it~ pre~ence would ~low down the progres~ of the hammer.
The acceleration o~ the hammer on the working ~troke i8 higher than in the Xnown apparatus. ~he hammer ~ aoted upon by alresultant force due to the pre~ure Or compressed air in the worXing-~troke chamber, which i8 connected to the compre~sed air line at regular intervale, and the pre~ure in the upper space o~ the idle-stroke chamber which is formed by the cylindrical protuberance o~ the chip8-recei~ing slee~e and communicates with the ~orking-stroke chamber~ The two forces acting on the hsmmer co~ncide i~ dire¢tion snd it~ ~peed on the working ~troko there~oro in¢rea~es.
Summing up, two ac¢eleratione of the hammer occur in the discloeed apparatus, on the idle ~troke ~,.
~6~454 3nd on the working one. ~here~ore, the frequency and impact foxce of the strokes i~crea~e~ there.
It i8 expedient that the channeling means i9 pro~ided in the ~orm of at lea~t a single lo~gi-tudinal groove which e~tend~ between the inlet portsof the case through a full-length ~troke of the hammer.
Thi3 plan permit~ an optimum perfor~ance of the ring-shaped hammer to be achieved in spite of a limited radial extent of its working ~uriace. An optimum relation#hip between the cross-se¢tional area of the chann~ling mean~ and the volume of the chambers which is established in thi~ case pro~ides ~or a minimum con~umption of compressed air~ ensur-in8 economical operation ~f the hammer unit andthe apparatus as a whole.
Briei~ Description of the Drawing~
A preferred embodiment of the invention will now be described with reference to the accompany-ing drawing~ in which Pig. 1 i~ a schematic cross-~ectional eleva-tion of the annular air-hammer apparatus for dril-; ling hole~ according to the in~ention, in a po~i-tion when the hammer strike~ again~t the rock-cut-ting tool~
-- 10 _ ~ ig. 2 i~ a ~chematic cro~s-~ectional eleva-tion o~ the annular air-hammer apparatu~ for dril-ling holes according to the in~ention, in a posi-t~on when the hammer i8 on the idle stroke and ar-rive~ at it~ topmo~t ~tation;
Fig. 3 i~ a as¢tion on line III-III of Fig. 1-Detailed Description of the I~Yention Referring to Fig~. 1 and 2, the annular air-hammer apparatus for drilling holes incorporates ~ a hollow ¢ylindrical ca~e 1 with a stepped bore.
A step 2 Or ~ smaller diameter locatad at the top of the case 1 i~ pro~ided with inlet ports 3 ad-mitted wherethrough irom a line i9 a compre~ed ga~eous fluid~i and a step 4 of a larger diameter 15 whioh faces the bottom holle is pro~ided with outlet ports 5. The case 1 is rigidly attached at its top to an external pipe 6 oi a concentric string 7.
rock-cutting tool 8 with an axial chips-receiv-ing opening 9 and blow ofi passages 10 i~ fitted 20 to the step 4 at the lower end oi the case 1 with pro~ieion for a~ial displacement. Contained in the bore of ths stepped ca~e 1 there are a stati¢ chips-receiving clee~e 11 and a ~teppod ring-shaped ham-mer 12 capablo of re¢iprocating ba¢k and forth 25 ¢on¢entri¢slly ~ith the ¢ace 1 ~o ae to form a ,, : , , .
i260~i4 working-stroke chamber 13 with the ca~e 1 and a~
ldle-~troke chamber 14 with the ca~e 1~ the rock-cutting tool 8 ~nd the chips-recei~ing ~leeve 11 The chambers 13 and 14 alternately communicate with the bottom hole 15 via the outlet ports ~.
The lower end 16 of the chips-recei~ing ~leeve 11 ~it~ into the axial chipa-receiving opening 9 of the rock-cutting tool 8~ and the upper end 17 of the chip~-receiving ~lee~e 11 i8 linked to the internal pipe 18 of ~e concentr~c string 7. A
cylindri¢al protuberance 19 of the ohips-recei~-ing slee~e 11 provided at the upper end thereof interacts with the bore 20 of the hammer 12 when thi~ arrives into its topmost position ~Pig. 2) ~o a~ to separate the idle-stroke chamber 14 into an upper space 21 and a lower space 22 which com-municates with eaoh other through an annular pas-sage 23. ~he idle-etroke chamber 14 18 pro~ided with a channeling means ln the form o~ a single lo~gitudinal groove 25 lo¢ated in the cyl~ndrical bore 24 of the step 2 o~ the case 1 between the in-let ports 3 (Figo 3). Alternati~ely, a plural~ty Or su¢h grooves 25 ¢an be provided for.
A ahell 26 ser~es to protect the apparatus, e.g- it~ work~n4-etroke chsmber 13, against an .. ..
':
, .....
. .
~604S4 lngres~ o~ chips. A pac~er 27 pro~ided at the bottom of the ~hell 26 i901ate9 the bottom hole 15 from L,he shell-borehole annulu~ 28 in order to induce a flow of spent air from the bottom hole 15 into the bore 29 o~ the chip~-receiving sleeve 11.
The fact that in the ambodiment of the inven-tion disclosed hereinabove the cylindrical protu-berance 19 o$ the chipa-receiving sleeve 11 at the upper end thereof interacts with the bore 20 of the hammer 12 and separate~ the upper ~pace 21 o~ the idle-~troke chamber 14 from the lower ~pace 22 thereof at regular interval~ and that the chan-neling means i8 provided in the idle-stroke cham-ber 14 at the side thereof faci~g the upper end face of the hammer 12 to bonnect this chamber to the compressed air line through the working-atroke chamber 13 at regular intervals when the hammer 12 arrive~ into its topmost position ensures an ef-fecti~e utilization of the area of the upper end ZO iace 30 of the hammer 12 with the result that the force~ acting thereupon during every operati~g cycle sugment and the performance of the apparatu~ (i.e.
the frequency and force of strokes) impro~es and its reliability in¢rea~es.
' 12604~4 In operation, the compressed air fed over the annular space between the internal pipe 18 (Fig. 1) and the external pipe 6 of the string 7 is admitted into the idle-stroke chamber 14 through the inlet ports 3, whereby the working-stroke chamber 13 is connected to the bore 29 of the chips-receiving sleeve 11 via the open outlet ports 5, the blow off passages 10 of the rock-cutting tool 8 and the bottom hole 15. The air admitted into the idle-stroke chamber 14 acts on both the upper and lower end faces 30 and 31, respectively, of the hammer 12.
The resulting forces oppose one another in direc-tion. However, the area of the lower end fase 31 is larger than that of the upper end face 30, and ; the hammer 12 starts moving upwards (Fig. 1), beginning an idle-stroke. As ~oon as collars 32 and 33 of the hammer 12 overlap the outlet ports 5 and the inlet ports 3, respectively, the flow of air ~ into the idle-stroke chamber 14 is interrupted. In - continuing on the idle stroke, the hammer reaches the cylindrical protuberance 19 of the chips-receiving sleeve 11 which closes the annular passage 23, separating thus the upper space 21 of the idle-stroke chamber 14 from the lower space 22 thereof. At the same time, the hammer 12 uncovers the longitudinal grooves 25 which connect the D
'`'' ' -" :
. ,~ . . .
. ~
: ' , .
12~0454 upper ~pace 21 of the idle-stroke chamber 14 to the working-~troke chamber 13. The air contained in the upper ~pace 21 o~ ~ idle-~troke chamber 14 escap~ into the working-stroke chamber 13, and the pre~sure in the two chambers 13 and 14 is equalized. But ~ince the volume of the working-stroke chamber 13 exceeds that of the idle-~troke chamber 14 three- to sixfold whereas the volume of the up-per space 21 oi the idle-~troke chnmber 14 i~ be-10 tween only 1/6 and 1J10 of the volume of the work-ing-stroke chamber 13, the equalized pres~ure in the two chamb~rs i8 slightly abo~e the atmo~pheric ~ressure and greatly le~s than the pressure in the compreesed air mains. The air pressure applied 15 to the upper end faoe 30 df the hammer 12 and hampering its progress decreases whereas the pres-sure which the air in the lower ~pace 22 of the ; idle-stroke chamber 14 exerts on the lower.~nd face 31 o~ the hammer 12 rem~ins unchanged. The 20 re~ultin~ pres~ure difference accelerate~ the hammer 12, e~abling it to complete the idle ~troke within a shorter time inter~al.
Purther upward progreos oi the hammer 12 oon-nects the outlet port~ 5 to the lower ~pace 22 25 Or the idle-stroke chamber 14 and the inlet port~ 3 ,, .
to the working-stroke chamber 13. The air contain-ed in the lower ~pace 22 of the idle-~troke cham-ber 14 e~capes, and compressed air is'admitted into the working-~troke chamber 13 and.hen¢e,into the upper ~psce 21'of the idle-stroke chamber 14 via the groove~ 24.
The air pressure ~et up in the two chambers and spplied to the upper end ~a¢e 30 of the hammer 12 and the annular area ~ormed due to the dif~e-rence between the diameter~ o~ the large-diameter collar 32 and the ~mall-diameter collar 33 causes the hammer 12 to stop a~d rever~e the direotion of its travel, 3tarting a working ~troke down~ards (Pig. 2)- As the ¢ollar~ 32 and 33 oi the hammer ~5 12 overlap the inlet ports 3 and the outlet ports 5, the source o~ the motive power of the hammer 12 i~ the energy of the a~r expanding in the working-~tro~e chamber 13 and the upper space 21 of the idle-~troke chamber 14. Continuing it~ downward travel, the hammer 12 disconnect~ the working-stroke ohamber 13 from,the upper space 21 o~ the idle-stroke chamber 14 due to its collar 32 which overlaps the longitudinal grooves 24 and connects the Uppor space 21 to the lower space 22.of the ' Z5 idle-stroke chamber ~4 through the uncovered i, iZ60454 -- 16 _ annuiar pa~age 23. The pres~ure in the two ~paces 21 and 22 of the idle-stroka chamber 14 equalizes-At the same time~ the inlet ports 3 are connected to the idle-~troke chamber 14 and the outlet ports 5 to the working-~troke chamber 13. The ~ir contain-ed in the working-stroke chs,mber 13 e~cspes and compres~ed air enters the idle-stroke chamb~r 14.
The hammer 12 strikes against the rock-cuttin~
tool 8, and the rock broken of~ i~ carried to the surface by ~ current of spent air ~ia the annular chips-recei~ing opening 9 in the rock-cutting tool 8, the bore 29 of the chip3-recei~ing sleeve 11 and the internal pipe 18 of the concentric ~tring 7.
The regular ~epsrations of the idle-stroke chamber 14 into two spaceb followed by the connec-tlons of its upper space 21 to the working-~troke chamber 13 are the factors whi¢h augment the forc-es applied to the hammer 12 in operation. The area of the hPmmer acting whereupon i~ compres~ed air i~ expanded both during the work~ng and idle strokes.
Th~ speed of the hammer 12 increases~ and the pe-riods of effecting the idle and working strokes sre shortened.
~he disclosed apparatus compares fa~ourably ~, 25 with the known annular air-hammer apparatus ~or .
., ,~.. . .
.
- ..
~O~S4 drilling holes, ~eatu~ing a 1 .5-fold increaee in the fre quency of stroke~, high impact ~tre~lgth and operstional reliability.
, . . .
Claims (2)
1. An annular air-hammer apparatus for drilling holes comprising:
a hollow cylindrical case with a stepped bore;
inlet ports provided in a step of a smaller inside diameter of said case;
outlet ports provided in a step of a larger inside diameter of said case;
a rock-cutting tool which has an axial opening and is attached to the forward end of said case;
a chips-receiving sleeve fixed inside said case concentrically therewith and extending throughout the full length thereof;
a stepped ring-shaped hammer which is fitted inside said case concentrically therewith with provision for reciprocating back and forth and has an axial bore passing wherethrough is said chips-receiving sleeve;
a source of compressed gaseous fluid;
a line for compressed gaseous fluid connected to said source of compressed gaseous fluid;
a working-stroke chamber which is formed in said case by said hammer and is connected to said line for compressed gaseous fluid through said inlet ports in order to provide motive power for said hammer on a working stroke thereof;
an idle-stroke chamber which is formed in said case by said rock-cutting tool and said chips-receiving sleeve and is connected to the bottom of a hole being drilled through said outlet ports in order to provide motive power for said hammer on an idle-stroke thereof and admit spent air into the bottom hole for delivering chips upwardly through said chips-receiving sleeve;
a cylindrical protuberance of said chips-receiving sleeve at an upper end thereof which interacts with said hammer, when said hammer arrives into its topmost position, and separates said idle-stroke chamber into an upper space and a lower space, reducing thereby the pressure of the compressed gaseous fluid in said idle-stroke chamber;
a channeling means which is located in said idle-stroke chamber and in the step of the smaller inside diameter which faces an upper end face of said hammer and serves to connect said working-stroke chamber to said upper space of said idle-stroke chamber which is connected to said line for compressed gaseous fluid at the instant when said hammer is in its topmost position.
a hollow cylindrical case with a stepped bore;
inlet ports provided in a step of a smaller inside diameter of said case;
outlet ports provided in a step of a larger inside diameter of said case;
a rock-cutting tool which has an axial opening and is attached to the forward end of said case;
a chips-receiving sleeve fixed inside said case concentrically therewith and extending throughout the full length thereof;
a stepped ring-shaped hammer which is fitted inside said case concentrically therewith with provision for reciprocating back and forth and has an axial bore passing wherethrough is said chips-receiving sleeve;
a source of compressed gaseous fluid;
a line for compressed gaseous fluid connected to said source of compressed gaseous fluid;
a working-stroke chamber which is formed in said case by said hammer and is connected to said line for compressed gaseous fluid through said inlet ports in order to provide motive power for said hammer on a working stroke thereof;
an idle-stroke chamber which is formed in said case by said rock-cutting tool and said chips-receiving sleeve and is connected to the bottom of a hole being drilled through said outlet ports in order to provide motive power for said hammer on an idle-stroke thereof and admit spent air into the bottom hole for delivering chips upwardly through said chips-receiving sleeve;
a cylindrical protuberance of said chips-receiving sleeve at an upper end thereof which interacts with said hammer, when said hammer arrives into its topmost position, and separates said idle-stroke chamber into an upper space and a lower space, reducing thereby the pressure of the compressed gaseous fluid in said idle-stroke chamber;
a channeling means which is located in said idle-stroke chamber and in the step of the smaller inside diameter which faces an upper end face of said hammer and serves to connect said working-stroke chamber to said upper space of said idle-stroke chamber which is connected to said line for compressed gaseous fluid at the instant when said hammer is in its topmost position.
2. An apparatus as claimed in claim 1, wherein said channeling means is provided in the form of at least a single longitudinal groove which extends between said inlet ports through a full-length stroke of said hammer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SU3955105 | 1985-09-16 | ||
| SU3955105 | 1985-09-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1260454A true CA1260454A (en) | 1989-09-26 |
Family
ID=21197934
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000516315A Expired CA1260454A (en) | 1985-09-16 | 1986-08-19 | Annular air-hammer apparatus for drilling holes |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS6299592A (en) |
| CA (1) | CA1260454A (en) |
| DE (1) | DE3628920A1 (en) |
| FI (1) | FI863725A (en) |
| FR (1) | FR2587407B1 (en) |
| GB (1) | GB2180279B (en) |
| SE (1) | SE461926B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111827918B (en) * | 2020-07-23 | 2022-07-26 | 北京大地高科地质勘查有限公司 | Novel plugging device for large-diameter pneumatic down-the-hole hammer reverse circulation drilling process |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2854461C2 (en) * | 1978-12-16 | 1983-03-10 | Wirth Maschinen- und Bohrgeräte-Fabrik GmbH, 5140 Erkelenz | Countersink hammer |
| US4509606A (en) * | 1980-10-29 | 1985-04-09 | Walker-Neer Manufacturing Co., Inc. | Axial return hammer |
| SU1133388A1 (en) * | 1983-06-07 | 1985-01-07 | Институт Горного Дела Со Ан Ссср | Pneumatic percussive tool for drilling holes |
-
1986
- 1986-08-19 CA CA000516315A patent/CA1260454A/en not_active Expired
- 1986-08-26 DE DE19863628920 patent/DE3628920A1/en active Granted
- 1986-08-27 GB GB08620689A patent/GB2180279B/en not_active Expired
- 1986-09-11 JP JP21283186A patent/JPS6299592A/en active Pending
- 1986-09-12 SE SE8603835A patent/SE461926B/en not_active Application Discontinuation
- 1986-09-15 FR FR8612875A patent/FR2587407B1/en not_active Expired
- 1986-09-15 FI FI863725A patent/FI863725A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| FR2587407A1 (en) | 1987-03-20 |
| FI863725A0 (en) | 1986-09-15 |
| GB8620689D0 (en) | 1986-10-08 |
| FI863725A (en) | 1987-03-17 |
| DE3628920C2 (en) | 1989-06-22 |
| SE8603835L (en) | 1987-03-17 |
| SE461926B (en) | 1990-04-09 |
| FR2587407B1 (en) | 1989-06-09 |
| GB2180279B (en) | 1988-08-17 |
| DE3628920A1 (en) | 1987-03-26 |
| SE8603835D0 (en) | 1986-09-12 |
| GB2180279A (en) | 1987-03-25 |
| JPS6299592A (en) | 1987-05-09 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |