CA2059661A1 - Relating to cutting apparatus - Google Patents
Relating to cutting apparatusInfo
- Publication number
- CA2059661A1 CA2059661A1 CA002059661A CA2059661A CA2059661A1 CA 2059661 A1 CA2059661 A1 CA 2059661A1 CA 002059661 A CA002059661 A CA 002059661A CA 2059661 A CA2059661 A CA 2059661A CA 2059661 A1 CA2059661 A1 CA 2059661A1
- Authority
- CA
- Canada
- Prior art keywords
- composition
- water
- mixing head
- abrasive
- fluent
- 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.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C7/00—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts
- B24C7/0007—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts the abrasive material being fed in a liquid carrier
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C7/00—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
- Processing Of Stones Or Stones Resemblance Materials (AREA)
- Crushing And Pulverization Processes (AREA)
- Confectionery (AREA)
Abstract
The invention provides cutting apparatus which is in the nature of a high pressure jet cutter. Water (16) at high pressure is supplied to a mixing head (14) and also supplied to the mixing head is a suspension (18) including abrasive particles, the particles being held in the suspension. The respective components are fed to a mixing head at different speeds, the water at high speed and the abrasive suspension at slow speed. The suspension is accelerated to match the water speed in the mixing head to ensure mixing.
The advantage of the arrangemet is that if the supply of materials to the jet cutter is stopped, the abrasive particles remain in suspension and do not settle out so that the apparatus can be restarted without difficulty. The invention also provides a mixing head enabling the above to be achieved.
The advantage of the arrangemet is that if the supply of materials to the jet cutter is stopped, the abrasive particles remain in suspension and do not settle out so that the apparatus can be restarted without difficulty. The invention also provides a mixing head enabling the above to be achieved.
Description
W091/01852 2 ~ ~ 9 ~ 6 ~: PCT/GB90/01222 IMPROVEME~TS R~L_TI~5 TO CUTTI~lG APPA~AT~S
.
This invention relates to cutting or abrading apparatus, and relates specifically to a jet cuttlng or abrading apparatus wherein a cutting fluid comprising a liquid carrier and abrasive is jetted in a fine stream to act as a cutting lance Eor cutting, -or exam?le, rigid shee~
materials.
A par,icula~ a?plication for the ?rese - inven~ o com?rises the cutting of lin ngs of ~i?es ~su_bi as underground sewers) where such linings bioc~ connec .ons between lateral connecting pipes and the main sewer.
The invention may also be used ~or cutting obstructions in pipes.
It is known for example from British Patent No. 1449455 to line a sewer to repair or rehabilitate same using soEt flexible lining material whicll is in ~he nature o~
a fibrous ~el~ im2regna~e~ ~i.l a ~Jra~`e s~nthe-i-resin. The lining tube is a?plied to the se~er s~Jrfaee and is then held in position until the resin cures to a hard condition froming a rigid l.ning pipe. In this process, the lining tube must be applied over the lateral connecting pipe.s, and these laterals must re re-opened using a cutting means which is placed in the lined pipe. The cutting apparatus oE the present invention is particularly sulta~le for this c~tting operation in that the Eine high ?ressu~e citting je~ can be used to cut a "coupon" Ero~ t~e lining in register with the lateral connection to be re-es~ablished b~
appropriate manipulation of the cu ting jet.
According to the present in~entlon there is ?ro~ide~ a method of high ?ressure jet cu ng com?rising feeding .
, ,, . -, : ~ . . : . .
- . . . - - - - , . . .... .
WO91/0185~ PCT/GB90/0122~
&
high pressure liquid carrler and an abrasive composition comprisin~ abrasive particles in suspension to a mixins head, deliverin~ the resultin~ mixture to a nozzle from which said issues as a high pre~asure cutting jet or je~s.
.
The carrier fluid preferably is water at a pressure in the order o~ U? to 4,000 psi.
It is known that water jet cutl:ing can be enhanced i' abrasive particles such as sand particles can be er.rained i~ the water, and this has already been pro2osed accordin~ to one ar-an~emen _a ~isclose~ in European patent no. 0 152 223.
In the said European patent, it is proposed to carry the abrasive particles to the nozzle along a separate supply line, and using air as a carrier medium to transport the abrasive particles. Immediately prior to mixin~ of the abrasive particles with the water at a mixing head, the carrying air and sand are separated, the air being vented, and the sand being carried through to the mixing head to mix with the water to become entrained therein and the mixture is expelled ,'-rom a nozzle.
This system works satisfactorily, but if there is failure of the air supply, the sand simply settles in the supply tube and is not satis~actorily taken up by ; the nozzle head.
The present invention provides for the delivery of abrasive particles to the mixin~ head, in a 'luent medium of such as to form wi~h the abrasive particles a suspension in which the abrasive particles are suspended in such a fashion that if there is failure in the supply ?ressure delivering the mixture to the nozzle head, the particles ~ill not ~all Olt o' s~spension. This arran~emen~ also has the considerable advanta~e tha~ the :, .' ~ .
-- . - . . . - . . . . .
- : : , . . . . .
. , . . . .. . .. -2 PCTtGB90/01222 : 3 ~9~
supply o~ the abrasive composition can be stopped and restarted without any deleterious effects.
It will ~e understood t~lere'ore t~at i' t~ere is a ~ailure of the pressure supplying the mixture tO the nozzle head, even if this is a negative inducing pressure, the mixture will simplv remain in the supply line with the particles in suspension unt-1 .such times as the ?ressure is re-esta~lishe~, when tne ~ixture ~ill be carried forward to the nozzle head as ' tnere had been no breakdown in the supply ~ressure.
Typica ly, the abrasive mater.a' ma~ ~e sanA, an~ a suitable fluent material ~or slspending sand .s water with a thickening thixotropic agent.
The mixture may be drawn into the high pressure water at the mixing head by virtue of venturi action.
., Preferably, the abrasive composition is delivered at a slower speed than the water to the mixing head, but at said mixing head the abrasive composition is acceletated Ilp to the speed of the water so that there is ef~ec~ive mixing. for delivery to the noz~'e.
, . , Preferably, the ratio o~ the throat restrictor ~or the abrasive compositions to that for the water, at the mixing head, as in the order o 3:20.
..
: The abrasive composition is preferably delivered to the mixing head by a twin piston pump arrangement the ~ pistons being connected in a bac~ to bac`~ or push-pull- configuration.
The water may be delivered by means of a high pressure water pump.
, ~ The instant invention is also concerlle~ with the -:
. : . . ,. .. . - .. , . ,, , ~; :,,: , , WO91/0]852 ~ PCT/G~90/01222 ~t~
apparatus for providing the fluid cuttin~ ~et, and also in accordance with the presen. invention, a high-pressure fluid cutting je~: ~2?ara~U5 com2 -ed an outlet nozzle for the jet, means supplving d car.i'r l:quid under pressure to the nozzle ani means for su?~lying a fluent composition comprising or containin~ ~he abrasive particles in suspension to said jet so tha~ the li~uid and composition mix in a mixing head to for~.. the final cutting jet, said means for supplyin~ the fluen~
composition comprising a pump means dr:ven bv the pressure of the carrier liquid.
The said punp means preferab:~y cOm?- 5~-c - ?a1r o piston pumps arranged back to bac'~ s~ o ha~e a common piston rod, with appr~?riate val~;;ng ?rov1ding that the pressurised carrier liauid is ap?lied alternately to the crown side of the p!ston of each pump, whilst the fluent composition is pumped by the rod side of the respective piston pumps and alternately, thereby to provide augmentation of the pressure in the fluent composition.
The fluent composition is p-eferably su??lled t_ the mixing head through a passage which is a frt^~ion o' the area of the passage through which the carrier liquid is supplied in order that the carrier liquid can ~e ap?lied in substantially greater voiume to the ~e~ than the ~luent composition, but so that the composition and carrier liquid are supplied to the jet at substantially the same velocity in order to ensure homogenous mixing of carrier liquid and fluent compo.sition.
The apparatus may embody a control shut~le valve controlling the supply of the carrier iiauid under pressure to the alternate piston ?umps, so tha- as one pump is pressurised, the othe^ :s exhaus~a-`, t~e shut~le valve being switched by a meanâ couple,1 to the sa~d common piston rod, and the ou~ e s from tn_ crown sides .! - ~ . . ~ : ' :
" ~' '. ' ' . ' ' , ' , ' ' ' '' ~ ' . ' ' . , :, . . . , ' ' '' ' ~' ' ' , ' : ,' ', ' ~ '' ' . :, '. , ~ :, '' ' ' , . ' , ' ' , ,, ' ' , . ' ' . ' .
', . ' . . ' . . .
.
W091/01852 PCT/GB90/OlZ22 2 ~ ~ ~ 6 6 of the piston pumps being provided with appropriate one-way valves to ensure that as fluent composition is being pumped from one o' said rod s:des to the nozzle, t~e other is drawing in a fresh su?plv o.' tne~ fluent composition ready to be charged to the nozzle at the next stroke of that pump.
The mixing head and nozzle may ~e as se. ~orth in British Patent Application ~o. 9009072.1. Embodiments of the present invention will now be described by way of example, with reference to the accompanying diagrammatic drawings, wherei~
Fig. 1 is a ciruit diagram of t~e hydra~ circ~ ~ of apparatus according to a ~irst embodiment o. the present invention;
., .
Fig. 2 is a view of an apparatus according to a second embodiment of the invention.
Referring to Fig. 1, the hydraulic circuit of the apparatus according to the embodiment of the invention comprises a water tank 10, water forming the pressurised liquid component of the system, a tank 12 for the composition of carrier matrix and abrasive, and a mixing head 14 to which a pressurised water line 16 and a pressurised fluent composition line 18 lead so that in the head 14, pressurised water and fluent material under pressure are mixed and together then pass along pipe 15 to an outlet nozzle 14A from which 14A and head 14 may be combined into a single un-t to perform the cutting operation.
The water travels in line 16 at greater speed than the composition in line 18 but in the head 1& are restrictors x and y for the composition flo~ and water ~low in order to ensure that the composition and ~ater meet at substantially the sa-,e velocit~. Su tably, the ;. -- - . , : . . -: ~ :
. .
'~ ~J`~
composition restrictor x may be 3~20tns ~' the cross-sectional area of the water restrictor y.
.~ .
The water is drawn from tank 10 ~y means of a pump 22 wllich may sup?ly water a~ 21 litres pe- ~inute a~ a pressure in the order of 2,000 psi The ou~put line 24 irom the pump 22 leads directly to the noz~lG 14, b~t also has a branch line 26 containing a 'low control valve 28 to divert say in th* order o' 3 litres per minute throu~h a shuttle val-- 3~1 d~p~ ^ upon ~-position as will be explained hereinaftei-The fluent composition is drawn from the tank 12 t~either one of a pair o ?umps 32, 34 ~ ich co~pr~sG
piston and cylinder devices, and the p.s~ons 36, 38 are arranged on a common piston rod 40 so thac pumps 32 and 34 are arranged back to back ~ centralising spring arrangement serves to bias the piston rod to the centralised positi~n shown in i-ig 1 The composition is drawn from the tank 12 through a line 44 and either oE two non-return valves 46, 48 in lines 50, 52 leading to the rod sides of pumps 32 and 34.
...
Two outlet pipes .rom pumps 32 an_ 3 indicate~
re~erence numerals 54 and 56 contain non-retuirn valves 58 and 60 and lead to an outlet line 62 which in turn couples with the fluent composition outlet pipe 18.
Operation of the apparatus oE ri9. 1 will be understcod from the above. When the apparatus is operational, the pistons 36 and 38 will be displaced back and forth in the pumps 32 and 34 and will operate the shuttle valve 30. ~ssume that the shuttle valv~ 30 is to the right-hand side of the blocking posi~ior, showr in Fi~ 2 ~n this case high pressure wateir ~rom tne pump 22 is charged into the crown end o' pump 34 d splacing the piston 3~ to the right oE ~ig 2 and ~orcing the composition in the rod side o' .h~ pisto tnr~ug~i line ' .... .. . . . . , : . .: ...................... . .:
:' ' . ; . ' ' ' . : - . . :.
, ' . . ~' ~' ' , 52, valve 60, line 56 and lin~ 62 ~o the n;~z%le l~ A~
the same time high pressure water is pumped via the line 24 to the nozzle 14 As regards the pu,mJ 32 during this opera.io,-" wa~er on the crown side of the piston 36 is forced through line 64 and the shuttle valve 30 to a return line 66 so that the water is returned to the t~nk, and at the same time a fresh supply o~ the fluent composition is drawn from tank 12 through line 44, valve ~6 and line 50 into the rod side of the pump The pisLon pair moves to the left until a detent on the rod 40 engages an operating leg of ; tne shuttle valve displacing the shuttle valve t_ i~s extreme ri~ht hand position in h~`nl^~ ?iston 3, and the movement o~ the piston assem~lAv eeverses so tha. the fluent composition im pump 32 is now discharged through line 50 o valve 58 and into line 62 A continuous supply of the Lluen~ composition and water ; through nozzle is therefore ensured, but the system can be stopped by stopping the pump 22 The amount of water which is used for displacing the pistons can be controlled by adjustment of th- ~lo~ contr~l valve 28 .~ .
In an embodiment of the invention in Fig 2, the , apparatus, comprises a nozzle head lOX containing a ,' nozzle outlet 12X from which the high velocity je. of water issues, the water being sùpplied via a high pressure water hose 14 at a pressure in the order o~
; 3,000 P.S.I. at 4 gallons per minute.
In the nozzle head lOX, the pipe 14X leads to a venLuri chamber 16X which is traversed ~y a feed pipe l8X ~or the mixture of the abrasive composi~ion The composition is drawn in accordance with well-established ;, venturi principles into the venturi chamber 16X in use through a small aperture 20X in t~,- pipe l4X and ~acing ~ , the nozzle 12X The abrasive com?osition ;s pumpe^, . .
: .
means o~ a motor 22X whic~ ~rivcs -a fe~ a~g.~t~ , in chamber 26x, to which the material is ~ ro~ a ~.ora~
hopper 28x.
The source of the material in .~pper 2Q~: and ~ .s~rce of high pressure water may be .ocated re~t~ly ro.~ tne nozzle head lOX which typically ~ill be loctated in .~ the pipeline where cutting is to take place.
., cross-connecting pipe 30X _~up!e.- ~,e ~ee~ ?ila- l3`;
for the composition and the water plpe l~X ani contains a flushing valve 32X wnich is normallv closed, .; but which can be opened when it i.s required to pu~,2 water through the pipe 18X in order ~o flush same ~f residual composition and/or abrasive.
.~ .
, .
The composition is such that the carrier mediu~ and the : abrasive are of like density and/or specific gravity so that the abrasive particles will remain in suspension in the carrier even in the event of Eailure of the pump 22X. In other words as in the Fig. I embodlmen~ there . will be minimum or no set~ling out o~ the abrasive even . when the system is not operational, dis~inguis~ing the . method and apparatus from the known arrangements.
- :
. Various materials may be used as the ahrasive ;- compositon, depending upon the natural interval being cut, provided that the abrasive particles do not settle ~ out of suspension too quickly (if at all) when the composition is left standing. 1- the par~icles se~
out within one hour the composi~ion being leEt standing, : that would be considered too quick.
., - : : .- . . .: .:
, .
.
WO91/~1852 9 PCT/GB90/01222 6 ~ ~
A suitable composition may comprise, by weight, the : following:-, :. a) ~ater200 parts b) Sand200 ?arts c) Thickening agent ~ parts d) Lubricating agent (to lubricate pump) ' ~arts . This composition may be mixed by weight Wit'l the water : in the retes o' ~ tO o (one ?ar. com?osi~ on to si~ -parts water).
.^
, .
: . ~
' ,
.
This invention relates to cutting or abrading apparatus, and relates specifically to a jet cuttlng or abrading apparatus wherein a cutting fluid comprising a liquid carrier and abrasive is jetted in a fine stream to act as a cutting lance Eor cutting, -or exam?le, rigid shee~
materials.
A par,icula~ a?plication for the ?rese - inven~ o com?rises the cutting of lin ngs of ~i?es ~su_bi as underground sewers) where such linings bioc~ connec .ons between lateral connecting pipes and the main sewer.
The invention may also be used ~or cutting obstructions in pipes.
It is known for example from British Patent No. 1449455 to line a sewer to repair or rehabilitate same using soEt flexible lining material whicll is in ~he nature o~
a fibrous ~el~ im2regna~e~ ~i.l a ~Jra~`e s~nthe-i-resin. The lining tube is a?plied to the se~er s~Jrfaee and is then held in position until the resin cures to a hard condition froming a rigid l.ning pipe. In this process, the lining tube must be applied over the lateral connecting pipe.s, and these laterals must re re-opened using a cutting means which is placed in the lined pipe. The cutting apparatus oE the present invention is particularly sulta~le for this c~tting operation in that the Eine high ?ressu~e citting je~ can be used to cut a "coupon" Ero~ t~e lining in register with the lateral connection to be re-es~ablished b~
appropriate manipulation of the cu ting jet.
According to the present in~entlon there is ?ro~ide~ a method of high ?ressure jet cu ng com?rising feeding .
, ,, . -, : ~ . . : . .
- . . . - - - - , . . .... .
WO91/0185~ PCT/GB90/0122~
&
high pressure liquid carrler and an abrasive composition comprisin~ abrasive particles in suspension to a mixins head, deliverin~ the resultin~ mixture to a nozzle from which said issues as a high pre~asure cutting jet or je~s.
.
The carrier fluid preferably is water at a pressure in the order o~ U? to 4,000 psi.
It is known that water jet cutl:ing can be enhanced i' abrasive particles such as sand particles can be er.rained i~ the water, and this has already been pro2osed accordin~ to one ar-an~emen _a ~isclose~ in European patent no. 0 152 223.
In the said European patent, it is proposed to carry the abrasive particles to the nozzle along a separate supply line, and using air as a carrier medium to transport the abrasive particles. Immediately prior to mixin~ of the abrasive particles with the water at a mixing head, the carrying air and sand are separated, the air being vented, and the sand being carried through to the mixing head to mix with the water to become entrained therein and the mixture is expelled ,'-rom a nozzle.
This system works satisfactorily, but if there is failure of the air supply, the sand simply settles in the supply tube and is not satis~actorily taken up by ; the nozzle head.
The present invention provides for the delivery of abrasive particles to the mixin~ head, in a 'luent medium of such as to form wi~h the abrasive particles a suspension in which the abrasive particles are suspended in such a fashion that if there is failure in the supply ?ressure delivering the mixture to the nozzle head, the particles ~ill not ~all Olt o' s~spension. This arran~emen~ also has the considerable advanta~e tha~ the :, .' ~ .
-- . - . . . - . . . . .
- : : , . . . . .
. , . . . .. . .. -2 PCTtGB90/01222 : 3 ~9~
supply o~ the abrasive composition can be stopped and restarted without any deleterious effects.
It will ~e understood t~lere'ore t~at i' t~ere is a ~ailure of the pressure supplying the mixture tO the nozzle head, even if this is a negative inducing pressure, the mixture will simplv remain in the supply line with the particles in suspension unt-1 .such times as the ?ressure is re-esta~lishe~, when tne ~ixture ~ill be carried forward to the nozzle head as ' tnere had been no breakdown in the supply ~ressure.
Typica ly, the abrasive mater.a' ma~ ~e sanA, an~ a suitable fluent material ~or slspending sand .s water with a thickening thixotropic agent.
The mixture may be drawn into the high pressure water at the mixing head by virtue of venturi action.
., Preferably, the abrasive composition is delivered at a slower speed than the water to the mixing head, but at said mixing head the abrasive composition is acceletated Ilp to the speed of the water so that there is ef~ec~ive mixing. for delivery to the noz~'e.
, . , Preferably, the ratio o~ the throat restrictor ~or the abrasive compositions to that for the water, at the mixing head, as in the order o 3:20.
..
: The abrasive composition is preferably delivered to the mixing head by a twin piston pump arrangement the ~ pistons being connected in a bac~ to bac`~ or push-pull- configuration.
The water may be delivered by means of a high pressure water pump.
, ~ The instant invention is also concerlle~ with the -:
. : . . ,. .. . - .. , . ,, , ~; :,,: , , WO91/0]852 ~ PCT/G~90/01222 ~t~
apparatus for providing the fluid cuttin~ ~et, and also in accordance with the presen. invention, a high-pressure fluid cutting je~: ~2?ara~U5 com2 -ed an outlet nozzle for the jet, means supplving d car.i'r l:quid under pressure to the nozzle ani means for su?~lying a fluent composition comprising or containin~ ~he abrasive particles in suspension to said jet so tha~ the li~uid and composition mix in a mixing head to for~.. the final cutting jet, said means for supplyin~ the fluen~
composition comprising a pump means dr:ven bv the pressure of the carrier liquid.
The said punp means preferab:~y cOm?- 5~-c - ?a1r o piston pumps arranged back to bac'~ s~ o ha~e a common piston rod, with appr~?riate val~;;ng ?rov1ding that the pressurised carrier liauid is ap?lied alternately to the crown side of the p!ston of each pump, whilst the fluent composition is pumped by the rod side of the respective piston pumps and alternately, thereby to provide augmentation of the pressure in the fluent composition.
The fluent composition is p-eferably su??lled t_ the mixing head through a passage which is a frt^~ion o' the area of the passage through which the carrier liquid is supplied in order that the carrier liquid can ~e ap?lied in substantially greater voiume to the ~e~ than the ~luent composition, but so that the composition and carrier liquid are supplied to the jet at substantially the same velocity in order to ensure homogenous mixing of carrier liquid and fluent compo.sition.
The apparatus may embody a control shut~le valve controlling the supply of the carrier iiauid under pressure to the alternate piston ?umps, so tha- as one pump is pressurised, the othe^ :s exhaus~a-`, t~e shut~le valve being switched by a meanâ couple,1 to the sa~d common piston rod, and the ou~ e s from tn_ crown sides .! - ~ . . ~ : ' :
" ~' '. ' ' . ' ' , ' , ' ' ' '' ~ ' . ' ' . , :, . . . , ' ' '' ' ~' ' ' , ' : ,' ', ' ~ '' ' . :, '. , ~ :, '' ' ' , . ' , ' ' , ,, ' ' , . ' ' . ' .
', . ' . . ' . . .
.
W091/01852 PCT/GB90/OlZ22 2 ~ ~ ~ 6 6 of the piston pumps being provided with appropriate one-way valves to ensure that as fluent composition is being pumped from one o' said rod s:des to the nozzle, t~e other is drawing in a fresh su?plv o.' tne~ fluent composition ready to be charged to the nozzle at the next stroke of that pump.
The mixing head and nozzle may ~e as se. ~orth in British Patent Application ~o. 9009072.1. Embodiments of the present invention will now be described by way of example, with reference to the accompanying diagrammatic drawings, wherei~
Fig. 1 is a ciruit diagram of t~e hydra~ circ~ ~ of apparatus according to a ~irst embodiment o. the present invention;
., .
Fig. 2 is a view of an apparatus according to a second embodiment of the invention.
Referring to Fig. 1, the hydraulic circuit of the apparatus according to the embodiment of the invention comprises a water tank 10, water forming the pressurised liquid component of the system, a tank 12 for the composition of carrier matrix and abrasive, and a mixing head 14 to which a pressurised water line 16 and a pressurised fluent composition line 18 lead so that in the head 14, pressurised water and fluent material under pressure are mixed and together then pass along pipe 15 to an outlet nozzle 14A from which 14A and head 14 may be combined into a single un-t to perform the cutting operation.
The water travels in line 16 at greater speed than the composition in line 18 but in the head 1& are restrictors x and y for the composition flo~ and water ~low in order to ensure that the composition and ~ater meet at substantially the sa-,e velocit~. Su tably, the ;. -- - . , : . . -: ~ :
. .
'~ ~J`~
composition restrictor x may be 3~20tns ~' the cross-sectional area of the water restrictor y.
.~ .
The water is drawn from tank 10 ~y means of a pump 22 wllich may sup?ly water a~ 21 litres pe- ~inute a~ a pressure in the order of 2,000 psi The ou~put line 24 irom the pump 22 leads directly to the noz~lG 14, b~t also has a branch line 26 containing a 'low control valve 28 to divert say in th* order o' 3 litres per minute throu~h a shuttle val-- 3~1 d~p~ ^ upon ~-position as will be explained hereinaftei-The fluent composition is drawn from the tank 12 t~either one of a pair o ?umps 32, 34 ~ ich co~pr~sG
piston and cylinder devices, and the p.s~ons 36, 38 are arranged on a common piston rod 40 so thac pumps 32 and 34 are arranged back to back ~ centralising spring arrangement serves to bias the piston rod to the centralised positi~n shown in i-ig 1 The composition is drawn from the tank 12 through a line 44 and either oE two non-return valves 46, 48 in lines 50, 52 leading to the rod sides of pumps 32 and 34.
...
Two outlet pipes .rom pumps 32 an_ 3 indicate~
re~erence numerals 54 and 56 contain non-retuirn valves 58 and 60 and lead to an outlet line 62 which in turn couples with the fluent composition outlet pipe 18.
Operation of the apparatus oE ri9. 1 will be understcod from the above. When the apparatus is operational, the pistons 36 and 38 will be displaced back and forth in the pumps 32 and 34 and will operate the shuttle valve 30. ~ssume that the shuttle valv~ 30 is to the right-hand side of the blocking posi~ior, showr in Fi~ 2 ~n this case high pressure wateir ~rom tne pump 22 is charged into the crown end o' pump 34 d splacing the piston 3~ to the right oE ~ig 2 and ~orcing the composition in the rod side o' .h~ pisto tnr~ug~i line ' .... .. . . . . , : . .: ...................... . .:
:' ' . ; . ' ' ' . : - . . :.
, ' . . ~' ~' ' , 52, valve 60, line 56 and lin~ 62 ~o the n;~z%le l~ A~
the same time high pressure water is pumped via the line 24 to the nozzle 14 As regards the pu,mJ 32 during this opera.io,-" wa~er on the crown side of the piston 36 is forced through line 64 and the shuttle valve 30 to a return line 66 so that the water is returned to the t~nk, and at the same time a fresh supply o~ the fluent composition is drawn from tank 12 through line 44, valve ~6 and line 50 into the rod side of the pump The pisLon pair moves to the left until a detent on the rod 40 engages an operating leg of ; tne shuttle valve displacing the shuttle valve t_ i~s extreme ri~ht hand position in h~`nl^~ ?iston 3, and the movement o~ the piston assem~lAv eeverses so tha. the fluent composition im pump 32 is now discharged through line 50 o valve 58 and into line 62 A continuous supply of the Lluen~ composition and water ; through nozzle is therefore ensured, but the system can be stopped by stopping the pump 22 The amount of water which is used for displacing the pistons can be controlled by adjustment of th- ~lo~ contr~l valve 28 .~ .
In an embodiment of the invention in Fig 2, the , apparatus, comprises a nozzle head lOX containing a ,' nozzle outlet 12X from which the high velocity je. of water issues, the water being sùpplied via a high pressure water hose 14 at a pressure in the order o~
; 3,000 P.S.I. at 4 gallons per minute.
In the nozzle head lOX, the pipe 14X leads to a venLuri chamber 16X which is traversed ~y a feed pipe l8X ~or the mixture of the abrasive composi~ion The composition is drawn in accordance with well-established ;, venturi principles into the venturi chamber 16X in use through a small aperture 20X in t~,- pipe l4X and ~acing ~ , the nozzle 12X The abrasive com?osition ;s pumpe^, . .
: .
means o~ a motor 22X whic~ ~rivcs -a fe~ a~g.~t~ , in chamber 26x, to which the material is ~ ro~ a ~.ora~
hopper 28x.
The source of the material in .~pper 2Q~: and ~ .s~rce of high pressure water may be .ocated re~t~ly ro.~ tne nozzle head lOX which typically ~ill be loctated in .~ the pipeline where cutting is to take place.
., cross-connecting pipe 30X _~up!e.- ~,e ~ee~ ?ila- l3`;
for the composition and the water plpe l~X ani contains a flushing valve 32X wnich is normallv closed, .; but which can be opened when it i.s required to pu~,2 water through the pipe 18X in order ~o flush same ~f residual composition and/or abrasive.
.~ .
, .
The composition is such that the carrier mediu~ and the : abrasive are of like density and/or specific gravity so that the abrasive particles will remain in suspension in the carrier even in the event of Eailure of the pump 22X. In other words as in the Fig. I embodlmen~ there . will be minimum or no set~ling out o~ the abrasive even . when the system is not operational, dis~inguis~ing the . method and apparatus from the known arrangements.
- :
. Various materials may be used as the ahrasive ;- compositon, depending upon the natural interval being cut, provided that the abrasive particles do not settle ~ out of suspension too quickly (if at all) when the composition is left standing. 1- the par~icles se~
out within one hour the composi~ion being leEt standing, : that would be considered too quick.
., - : : .- . . .: .:
, .
.
WO91/~1852 9 PCT/GB90/01222 6 ~ ~
A suitable composition may comprise, by weight, the : following:-, :. a) ~ater200 parts b) Sand200 ?arts c) Thickening agent ~ parts d) Lubricating agent (to lubricate pump) ' ~arts . This composition may be mixed by weight Wit'l the water : in the retes o' ~ tO o (one ?ar. com?osi~ on to si~ -parts water).
.^
, .
: . ~
' ,
Claims (12)
1. A method of high pressure jet cutting comprising feeding high pressure liquid carrier and an abrasive composition comprising abrasive particles in suspension to a mixing head, delivering the resulting mixture to a nozzle from which the mixture issues as a high pressure cutting jet or jets.
2. The method according to Claim 1, wherein the carried fluid is water at a pressure in the order of up to 4,000 psi.
3. A method according to Claim 1 or 2, wherein the abrasive composition comprises a mixture of water, abrasive particles and a thickening agent .
4. A method according to any preceeding Claim, wherein the abrasive composition is delivered at a slower speed than the water to the mixing head, but at said mixing head the abrasive composition is accelerated up to the speed of the water so that there is effective mixing for delivery to the nozzle.
5. A method according to Claim 4 wherein the ratio of the throat restrictor for the abrasive composition to that for the water at the mixing head is in the order of 3 to 20.
6. A method according to any preceeding Claim, wherein the abrasive composition is delivered to the mixing head by a twin piston pump arrangement, the pistons being connected in a back-to-back or push-pull configuration.
7. A method according to any preceeding Claim wherein the water is delivered to the mixing head by means of a high pressure water pump.
8. Apparatus for providing a high pressure cutting jet comprising an outlet nozzle for the jet, means supplying a carrier liquid under pressure to the nozzle and means for supplying a fluent composition comprising or containing abrasive particles in suspension to said jets so that the liquid and composition mix in a mixing head to form the final cutting jet, said means for supplying the fluent composition comprising a pump means driven by the pressure of the carrier liquid.
9. Apparatus according to Claim 8, wherein the pump means comprises a pair of piston pumps arranged back-to-back so as to have a common piston rod, with appropriate valving providing that the pressurised carrier liquid is applied alternatively to the crown side of the piston of each pump, whilst the fluent composition is pumped by the rod side of the respective piston pumps and alternately, thereby to provide augmentation of the pressure in the fluent composition.
10. Apparatus according to Claim 9, wherein the fluent composition is supplied to the mixing head through a passage which is a fraction of the area of the passage through which the carrier liquid is supplied in order that the carrier liquid can be applied in substanaially greater volume to the jet than the fluent composition, but so that the composition and carrier liquid are supplied to the jet at subastantially the same velocity in order to ensure homogeneous mixing of the carrier liquid and fluent composition.
11. Apparatus according to Claim 10 wherein the apparatus includes a shuttle bob controlling the supply of the carrier liquid under pressure to the alternate piston pumps, so that as one pump is pressurised, the other is exhausted, the shuttle valve being switched by means coupled to said common piston rod, and the outlets from the crown sides of the piston pumps being provided with appropriate one-way valves to ensure that as fluent composition is being pumped from one of said rod sides to the nozzle, the other is drawing in a fresh supply of the fluent composition ready to be charged to the nozzle at the next stroke of that pump.
12. A mixing head for use in the apparatus according to any Claims 8 - 11, said mixing head comprising a coupling for connection to an abrasive composition supply, and a coupling for connection to a high pressure water supply, said coupling including restrictors, the restrictor in the composition coupling being a fraction of the area of the restrictor in the water coupling.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB898917987A GB8917987D0 (en) | 1989-08-07 | 1989-08-07 | Improvements relating to water cutting apparatus |
| GB8917987.3 | 1989-08-07 | ||
| GB9005409.9 | 1990-03-10 | ||
| GB909005409A GB9005409D0 (en) | 1990-03-10 | 1990-03-10 | Improvements relating to cutting apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2059661A1 true CA2059661A1 (en) | 1991-02-08 |
Family
ID=26295712
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002059661A Abandoned CA2059661A1 (en) | 1989-08-07 | 1990-08-06 | Relating to cutting apparatus |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0485502A1 (en) |
| JP (1) | JPH04506938A (en) |
| KR (1) | KR920703272A (en) |
| AU (1) | AU6179190A (en) |
| CA (1) | CA2059661A1 (en) |
| FI (1) | FI920423A7 (en) |
| WO (1) | WO1991001852A1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1992011116A1 (en) * | 1990-12-17 | 1992-07-09 | Tadeusz Stec | Method of cutting amorphous materials using liquid |
| WO1995022432A1 (en) * | 1994-02-21 | 1995-08-24 | Waterkracht B.V. | Blasting device with adjustable blast strength |
| GB9719550D0 (en) * | 1997-09-16 | 1997-11-19 | Miller Donald S | Fluid abrasive jets for machining |
| AUPR355401A0 (en) * | 2001-03-02 | 2001-04-05 | Jet-Net International Pty Ltd | High pressure liquid nozzle assembly operating method |
| US8834232B2 (en) | 2007-08-21 | 2014-09-16 | Abrasive Cutting Technology Ltd. | Fluid/abrasive jet cutting arrangement |
| AU2008288702B2 (en) * | 2007-08-21 | 2014-07-31 | Jet-Tech International Pty Ltd | A control system for a fluid/abrasive jet cutting arrangement |
| RU2500518C2 (en) * | 2007-08-21 | 2013-12-10 | Абрейсив Каттинг Текнолоджи Лтд | Cutting tool and cutting nozzle for hydroabrasive cutting tool |
| AU2009233523B8 (en) * | 2008-04-05 | 2015-06-25 | SC Projects Pty Ltd | Abrasive cutting fluids |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB602330A (en) * | 1943-12-23 | 1948-05-25 | Pangborn Corp | Hydraulic sand feeder |
| NL92868C (en) * | 1952-05-31 | |||
| GB1008503A (en) * | 1962-07-12 | 1965-10-27 | Ajem Lab Inc | Process and apparatus for the surface treatment of articles |
| GB1424896A (en) * | 1973-05-25 | 1976-02-11 | Hart B E | Jet forming apparatus |
| DE2724318C2 (en) * | 1977-05-28 | 1984-09-20 | Ernst Peiniger GmbH Unternehmen für Bautenschutz, 4300 Essen | Process for moistening the abrasive when blasting with compressed air |
| GB2075879B (en) * | 1980-05-16 | 1983-04-07 | Link John | Cleaning apparatus and method |
| GB2128911B (en) * | 1982-10-22 | 1986-04-16 | Shiftworker Limited | Sand blasting apparatus |
| EP0152223B1 (en) * | 1984-02-09 | 1990-09-05 | C. Barriquand et Fils | High pressure jets |
| CA1298708C (en) * | 1985-10-10 | 1992-04-14 | Roger Artinade Heron | Feeding abrasive material |
| EP0313700A3 (en) * | 1987-10-29 | 1990-01-24 | Ingersoll-Rand Company | Abrasive-jet cutting system |
| GB8708499D0 (en) * | 1987-04-09 | 1987-05-13 | Baldwin & Stanton Ltd | Abrasive blasting apparatus |
| SE462116B (en) * | 1988-09-27 | 1990-05-07 | Atlas Copco Mct Ab | DEVICE FOR PROCESSING HARD MATERIALS |
-
1990
- 1990-08-06 CA CA002059661A patent/CA2059661A1/en not_active Abandoned
- 1990-08-06 KR KR1019920700210A patent/KR920703272A/en not_active Withdrawn
- 1990-08-06 EP EP90912675A patent/EP0485502A1/en not_active Withdrawn
- 1990-08-06 JP JP2511796A patent/JPH04506938A/en active Pending
- 1990-08-06 FI FI920423A patent/FI920423A7/en not_active Application Discontinuation
- 1990-08-06 WO PCT/GB1990/001222 patent/WO1991001852A1/en not_active Application Discontinuation
- 1990-08-06 AU AU61791/90A patent/AU6179190A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| EP0485502A1 (en) | 1992-05-20 |
| AU6179190A (en) | 1991-03-11 |
| FI920423A0 (en) | 1992-01-30 |
| JPH04506938A (en) | 1992-12-03 |
| KR920703272A (en) | 1992-12-17 |
| WO1991001852A1 (en) | 1991-02-21 |
| FI920423A7 (en) | 1992-01-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |