CA1175111A - Cooling and height sensing system for a plasma arc cutting tool - Google Patents
Cooling and height sensing system for a plasma arc cutting toolInfo
- Publication number
- CA1175111A CA1175111A CA000393702A CA393702A CA1175111A CA 1175111 A CA1175111 A CA 1175111A CA 000393702 A CA000393702 A CA 000393702A CA 393702 A CA393702 A CA 393702A CA 1175111 A CA1175111 A CA 1175111A
- Authority
- CA
- Canada
- Prior art keywords
- nozzle
- torch
- ports
- plasma arc
- cooling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K10/00—Welding or cutting by means of a plasma
Abstract
ABSTRACT OF THE DISCLOSURE
A plasma arc cutting torch cools its nozzle with a water flow between an inner metallic nozzle member and an outer ceramic nozzle member. A set of auxiliary ports formed in the ceramic element each extend from an associated radial channel that directs a portion of the water to the plasma arc where it forms an annular "jet" that constricts the arc. The auxiliary ports are located and sized to provide an enhanced flow of water through the nozzle while maintaining an optimal flow rate through the radial channel, When a gas flow through the cooling passages is used to sense the height of the torch over a work-piece, the gas flow through the auxiliary ports clears residual water from the nozzle to avoid a false height sensing due to an emission of droplets of the water.
A plasma arc cutting torch cools its nozzle with a water flow between an inner metallic nozzle member and an outer ceramic nozzle member. A set of auxiliary ports formed in the ceramic element each extend from an associated radial channel that directs a portion of the water to the plasma arc where it forms an annular "jet" that constricts the arc. The auxiliary ports are located and sized to provide an enhanced flow of water through the nozzle while maintaining an optimal flow rate through the radial channel, When a gas flow through the cooling passages is used to sense the height of the torch over a work-piece, the gas flow through the auxiliary ports clears residual water from the nozzle to avoid a false height sensing due to an emission of droplets of the water.
Description
e~Ke~s~sLs~ 2L~ENTION
This invention relates in qeneral -to plasma arc cut-tiny torches and more particularly to an improved noææle construction that provides enhanced cooliny and a more reliable initial height sensing.
The present invention is an improvement over the cutting torches and height sensing method dèscribed in U.S.
Patent Nos. 3,641,308 and 4,203,022. The '308 patent describes a nozzle for a plasma arc cutting torch where a laminar jet of a cooling liquid, usually water, surrounds and constricts the plasma. The liquid jet is created by a pair of generally annular members which toge-ther form the nozzle oE the torch. The inner member has a central passageway that directs an ionizable ~as from an electrode to a workpiece located helow the electrode.
The outer member cooperates with the inner one to create an annu-lar nozæle that emits the liquid jet. The effectiveness of this ~ '75~
1 system in ConCentratinCJ the art depends, in part, on the water mass flow rate and Elow veloc:ity creatin~ the constric-ting water jet.
The '022 paten-t describes a method and apparatus for sensing the height of the torch ovex a workpiece, particularly as the torch is lo~ered toward the workpiece to begin cutting.
Height sensing is important since the outer annular member of the torch nozzle is typically a ceramic material that can be damaged through contact with the workpiece. The '022 patent teaches tha-t a gas flow can be introduced through ~e gas system as the torch is lowered. The gas stream swirls and has a vortex pressure. When the torch is closely spaced from the workpiece, the vortex '1a-ttaches" to the workpiece resulting in an abrllpt change in the vortex pressure. rrhis change is sensed and gives the desired height information. One source of unreliabillty with this system arises out of residual water which is often present in the water ejection area of the nozzle, particularly when the nozzle is worn. Also, during the height sensing operation, if a droplet of residual water is ejected by the gas flow, the droplet can cause a pressure fluctuation which can be interpreted incorrectly as an indication that the torch is at the proper height over the workpiece.
~ ore generally, the performance of a plasma arc cutting torch is directly related to the ability of the cutting system to cool the nozzle of the torch. The cooler the nozzle, the larger the current that the plasma can conduct. Also, a cool nozzle has an extended life since less scale and deposits form on the nozzle. In a water cooled torch of the general type shown in the '308 and '022 patents, heretofore it has not been possible to simply increase cooling by increasing the water ~low ~2--.
~7~
1 because the la~inar jet used to constr.ict the plasma is sensitive to flow parameters.
It is therefore a principal object of this invention to provide a plasma arc cutting torch that has its plasma arc con-centrated by a jet of a cooling liqu:id while at the same time offering markedly increased cooling as compared to conventional torches of this type.
Another object is to provide a nozzle construction with an extended useful life.
1~ A further object is to provide a nozzle construc-tion which avoids unreliabi.lity in the initial height sensing due to the presence of residual water in the nozzle.
Yet anokher object is to provide an improved plasma arc cutting torch with the foregoing advantages which has a com petitive cost of manufacture as compared to conventional torches of the same general type.
These and other objects and features will be more fully understood from the following detailed description which should be read in light of the accompanying drawings.
BRIEF DESCRIPTION OF THE DR~WINGS
Fig. 1 is a view in ver-tical section showing the lower portion of a plasma arc cutting torch cons-tructed according to the present invention; and Fig. 2 is a bottom plan view of the torch shown in Fig. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
... ~ . . . _ _ . . . . .
Fig. 1 shows the lower portion of a plasma arc cutting torch 12 of the general type described in U.S. Patent Nos.
3,641,308 and 4,203,022 and manufactured and sold by Hypertherm, Inc. of Hanover, New Hampshire under the trade designation model .
, ' ;~
`` ll~L~75~
PAC-S00. ~ dekailed description of the torch and its support systems can be found in these patents and will not be repeated here. This type oE torch :is convenkionally operated to generate a plasma arc in an ioni2able gas such as nitrogen ~N2) with a helical swirl being impar-ted to the gas wlthin the torch to improve the characteristics of the cut. The arc extends generally from an electrode 14 to a metal workpiece such as a steel plate (not shown). The torch al50 uses a water injection ~ystem to cool its nozzle 16 and to constrict the plasma arc as it is emi-tted from the torch.
The nozzle 16 has two principal components, an inner nozzle member 18 and an outer member 20. The inner member 18 is typically made of copper and the outer element 20 is cer-amic; both have a generally a~nular configuration. As shown, the ceramic member 20 generally surrounds the lateral and lower outer surfaces of the metallic member 18. The member 1~, in com-bination with the electrode 16 defines a flow path 22 for the plasma gas. The gas enters the path 22 at the point 22a with a helical swirl imparted by a set of tangential ports in a ring (not-shown) mounted just above the inner member. The plasma gas then flows downwardly through a central passa~eway 24 of the member 18 to the workpiece~
The members 18 and 20 are in a generally abutting re-lationship with one another except for a generally radially arrayed channel 26 formed at their interface and adapted to con~
duct a cooliny fluid, typically water, from an annular region adjacent the upper lateral surfaces 18a and 20a of the members to a point 26a adjacent the plasma arc near its point of exit from the torch. Cooled water flowing through the channel 26 cools the member 18. Radial jet of water ejected from the channel 7~
1 a-t the point 26a creates a laminar .jet oE water which constricts and concentrates the plasma in the manner de~cribed in the afoxe-mentioned patents.
A principal feature o~ -the present inven-tion is a set of auxiliary ports 28 formed in the ceramic, outer member 20.
Each port 28 extends from the channeL 26 at A point 30 to the lower face 20b of the ceramic element. In the preferred form shown, there are eight auxiliary ports spaced yenerally equiangu-larly about the central passageway 24. Each port 28 is also spaced radially ~rom the passageway 24 a sufficient distance that the effluent flow of cooling water from the ports 28 does not interfere with the cut. To the same efEect, the ports 28 are directed generally vertically, parallel to the path of the arc from the electrode to the workpiece. The location and con~
centration of the ports 28 can vary provided that the ef~luent water does not in-terfere with the cut.
The ports 28 divert a portion of the cooling waker from the channel 26 before they tr~verse the final length 26c Oe the channel (extending from the point 30 to the point 26a). As a result, there is an increased mass flow rate and/or flow velocity over the prece~ing, upstream portions 26d of the channel 26 as compared to conventional torches of this type where all of the nozzle cooling water is ejected into the laminar jet that con-strains the plasma. This increased flow provides a greater cooling of the nozzle which in turn allows the nozzle to be operated at increased current levels or, for operation at con-ventional current levels, at a cooler temperature. With the present invention, it has been found that it is possible to in-crease the maximum current by approximately 25%. Cooler operating temperatures result in a longer nozzle life since they are .
~ t7~
1 associated with less scale and deposits bein~ ~ormed on the nozzle~
The dimensions of the porta 28 are selected ln conjunc-tion with those of the channel 26 so that the water flow through the channel portion 26c is a-t a su~ficient rate and veloclty to cons-tri.ct the plasma arc as taught in the aforementioned patents.
For the Hypertherm model PAC-500 torch with a 0.12 inch nozzle, the ports 28 should divert approximately 30% of the cooling water while 70% of the water flows through the channel'portion 26c.
A port diameter of approximately 0.032 inch has been found to be satisfactory. For different torches, however, the dimensions and ratios will, of course, vary. The percentage of water carried by the ports 28 will usually lie in the range oP 20~ to 50~.
The nozzle construction of the present invenkion is also useful in connection with the height sensing proc~dure which is the subject of U.S. Patent No. 4,203,022. In that procedure, the supply of water to the water cooling system for the nozzle is shut off and a supply of gas is directed through the system.
The tangential ports create a swirling movement in the gas to generate a vortex. The vortex is weak until the torch is close to the workpiece and "attaches'7 to it. This attachment is accom panied by an ahrupt drop in the vortex pressure which is sensed by a transducer.
One problem with this system has been the presence of residual water in the channel 26 which can cause erratic pressure readings, commonly termed "spitting", or can result in a alse indication that the torch is properly positioned due to the ejection of droplets of residual water. This latter situation is particularly troublesome when the nozzle becomes worn at the site of ejection and the residual water film is.unstable. With f~'7~
1 the present inven-tion, during the in:itial he:ight sensing process the ya.s flow drives residual water out oE the nozzle throuyh the por-ts 28. The residual water therefore does no-t interfere with the height sensing process. It shou].d also be noted that the eEfluent gas :Elow from the ports 28 also does not interfere with the height sensing.
While the invention had been described with respect to its preEerred embodiments, it will be understood that various modifications and variations will occur to those skilled in the art from the foregoing detalled description and the accompanyiny drawings. Such modifications and variations are intended to fall within the scope of the appended claims.
~.
.
This invention relates in qeneral -to plasma arc cut-tiny torches and more particularly to an improved noææle construction that provides enhanced cooliny and a more reliable initial height sensing.
The present invention is an improvement over the cutting torches and height sensing method dèscribed in U.S.
Patent Nos. 3,641,308 and 4,203,022. The '308 patent describes a nozzle for a plasma arc cutting torch where a laminar jet of a cooling liquid, usually water, surrounds and constricts the plasma. The liquid jet is created by a pair of generally annular members which toge-ther form the nozzle oE the torch. The inner member has a central passageway that directs an ionizable ~as from an electrode to a workpiece located helow the electrode.
The outer member cooperates with the inner one to create an annu-lar nozæle that emits the liquid jet. The effectiveness of this ~ '75~
1 system in ConCentratinCJ the art depends, in part, on the water mass flow rate and Elow veloc:ity creatin~ the constric-ting water jet.
The '022 paten-t describes a method and apparatus for sensing the height of the torch ovex a workpiece, particularly as the torch is lo~ered toward the workpiece to begin cutting.
Height sensing is important since the outer annular member of the torch nozzle is typically a ceramic material that can be damaged through contact with the workpiece. The '022 patent teaches tha-t a gas flow can be introduced through ~e gas system as the torch is lowered. The gas stream swirls and has a vortex pressure. When the torch is closely spaced from the workpiece, the vortex '1a-ttaches" to the workpiece resulting in an abrllpt change in the vortex pressure. rrhis change is sensed and gives the desired height information. One source of unreliabillty with this system arises out of residual water which is often present in the water ejection area of the nozzle, particularly when the nozzle is worn. Also, during the height sensing operation, if a droplet of residual water is ejected by the gas flow, the droplet can cause a pressure fluctuation which can be interpreted incorrectly as an indication that the torch is at the proper height over the workpiece.
~ ore generally, the performance of a plasma arc cutting torch is directly related to the ability of the cutting system to cool the nozzle of the torch. The cooler the nozzle, the larger the current that the plasma can conduct. Also, a cool nozzle has an extended life since less scale and deposits form on the nozzle. In a water cooled torch of the general type shown in the '308 and '022 patents, heretofore it has not been possible to simply increase cooling by increasing the water ~low ~2--.
~7~
1 because the la~inar jet used to constr.ict the plasma is sensitive to flow parameters.
It is therefore a principal object of this invention to provide a plasma arc cutting torch that has its plasma arc con-centrated by a jet of a cooling liqu:id while at the same time offering markedly increased cooling as compared to conventional torches of this type.
Another object is to provide a nozzle construction with an extended useful life.
1~ A further object is to provide a nozzle construc-tion which avoids unreliabi.lity in the initial height sensing due to the presence of residual water in the nozzle.
Yet anokher object is to provide an improved plasma arc cutting torch with the foregoing advantages which has a com petitive cost of manufacture as compared to conventional torches of the same general type.
These and other objects and features will be more fully understood from the following detailed description which should be read in light of the accompanying drawings.
BRIEF DESCRIPTION OF THE DR~WINGS
Fig. 1 is a view in ver-tical section showing the lower portion of a plasma arc cutting torch cons-tructed according to the present invention; and Fig. 2 is a bottom plan view of the torch shown in Fig. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
... ~ . . . _ _ . . . . .
Fig. 1 shows the lower portion of a plasma arc cutting torch 12 of the general type described in U.S. Patent Nos.
3,641,308 and 4,203,022 and manufactured and sold by Hypertherm, Inc. of Hanover, New Hampshire under the trade designation model .
, ' ;~
`` ll~L~75~
PAC-S00. ~ dekailed description of the torch and its support systems can be found in these patents and will not be repeated here. This type oE torch :is convenkionally operated to generate a plasma arc in an ioni2able gas such as nitrogen ~N2) with a helical swirl being impar-ted to the gas wlthin the torch to improve the characteristics of the cut. The arc extends generally from an electrode 14 to a metal workpiece such as a steel plate (not shown). The torch al50 uses a water injection ~ystem to cool its nozzle 16 and to constrict the plasma arc as it is emi-tted from the torch.
The nozzle 16 has two principal components, an inner nozzle member 18 and an outer member 20. The inner member 18 is typically made of copper and the outer element 20 is cer-amic; both have a generally a~nular configuration. As shown, the ceramic member 20 generally surrounds the lateral and lower outer surfaces of the metallic member 18. The member 1~, in com-bination with the electrode 16 defines a flow path 22 for the plasma gas. The gas enters the path 22 at the point 22a with a helical swirl imparted by a set of tangential ports in a ring (not-shown) mounted just above the inner member. The plasma gas then flows downwardly through a central passa~eway 24 of the member 18 to the workpiece~
The members 18 and 20 are in a generally abutting re-lationship with one another except for a generally radially arrayed channel 26 formed at their interface and adapted to con~
duct a cooliny fluid, typically water, from an annular region adjacent the upper lateral surfaces 18a and 20a of the members to a point 26a adjacent the plasma arc near its point of exit from the torch. Cooled water flowing through the channel 26 cools the member 18. Radial jet of water ejected from the channel 7~
1 a-t the point 26a creates a laminar .jet oE water which constricts and concentrates the plasma in the manner de~cribed in the afoxe-mentioned patents.
A principal feature o~ -the present inven-tion is a set of auxiliary ports 28 formed in the ceramic, outer member 20.
Each port 28 extends from the channeL 26 at A point 30 to the lower face 20b of the ceramic element. In the preferred form shown, there are eight auxiliary ports spaced yenerally equiangu-larly about the central passageway 24. Each port 28 is also spaced radially ~rom the passageway 24 a sufficient distance that the effluent flow of cooling water from the ports 28 does not interfere with the cut. To the same efEect, the ports 28 are directed generally vertically, parallel to the path of the arc from the electrode to the workpiece. The location and con~
centration of the ports 28 can vary provided that the ef~luent water does not in-terfere with the cut.
The ports 28 divert a portion of the cooling waker from the channel 26 before they tr~verse the final length 26c Oe the channel (extending from the point 30 to the point 26a). As a result, there is an increased mass flow rate and/or flow velocity over the prece~ing, upstream portions 26d of the channel 26 as compared to conventional torches of this type where all of the nozzle cooling water is ejected into the laminar jet that con-strains the plasma. This increased flow provides a greater cooling of the nozzle which in turn allows the nozzle to be operated at increased current levels or, for operation at con-ventional current levels, at a cooler temperature. With the present invention, it has been found that it is possible to in-crease the maximum current by approximately 25%. Cooler operating temperatures result in a longer nozzle life since they are .
~ t7~
1 associated with less scale and deposits bein~ ~ormed on the nozzle~
The dimensions of the porta 28 are selected ln conjunc-tion with those of the channel 26 so that the water flow through the channel portion 26c is a-t a su~ficient rate and veloclty to cons-tri.ct the plasma arc as taught in the aforementioned patents.
For the Hypertherm model PAC-500 torch with a 0.12 inch nozzle, the ports 28 should divert approximately 30% of the cooling water while 70% of the water flows through the channel'portion 26c.
A port diameter of approximately 0.032 inch has been found to be satisfactory. For different torches, however, the dimensions and ratios will, of course, vary. The percentage of water carried by the ports 28 will usually lie in the range oP 20~ to 50~.
The nozzle construction of the present invenkion is also useful in connection with the height sensing proc~dure which is the subject of U.S. Patent No. 4,203,022. In that procedure, the supply of water to the water cooling system for the nozzle is shut off and a supply of gas is directed through the system.
The tangential ports create a swirling movement in the gas to generate a vortex. The vortex is weak until the torch is close to the workpiece and "attaches'7 to it. This attachment is accom panied by an ahrupt drop in the vortex pressure which is sensed by a transducer.
One problem with this system has been the presence of residual water in the channel 26 which can cause erratic pressure readings, commonly termed "spitting", or can result in a alse indication that the torch is properly positioned due to the ejection of droplets of residual water. This latter situation is particularly troublesome when the nozzle becomes worn at the site of ejection and the residual water film is.unstable. With f~'7~
1 the present inven-tion, during the in:itial he:ight sensing process the ya.s flow drives residual water out oE the nozzle throuyh the por-ts 28. The residual water therefore does no-t interfere with the height sensing process. It shou].d also be noted that the eEfluent gas :Elow from the ports 28 also does not interfere with the height sensing.
While the invention had been described with respect to its preEerred embodiments, it will be understood that various modifications and variations will occur to those skilled in the art from the foregoing detalled description and the accompanyiny drawings. Such modifications and variations are intended to fall within the scope of the appended claims.
~.
.
Claims (6)
1. In a plasma arc cutting apparatus having a nozzle through which the plasma arc is ejected, said nozzle including (i) an inner member with a central passageway that directs said plasma arc from an electrode to a workpiece, (ii) an outer member which generally surrounds said inner member, and (iii) a fluid passage formed generally between said inner and outer members which directs a flow of cooling liquid about said inner member, said fluid passage having a generally radially directed channel portion adapted to establish a generally annular jet of said cooling liquid around said plasma, the improvement comprising a plurality of auxiliary ports formed in said outer nozzle member, each of said ports (i) being in fluid communication with said fluid passage, (ii) extending to the outer surface of said outer member in a direction that directs the cooling liquid carried by said ports away from the cutting area, and (iii) having a cross sectional dimension that provides an enhanced flow rate of the cooling fluid through said nozzle while providing a flow rate through said channels at a value conducive to maximize the efficiency of said cutting.
2. The improvement of claim 2 wherein said auxiliary ports each extend generally in the direction of said plasma arc and are spaced radially from said annular column of cooling fluid.
3. The improvement of claim 2 wherein said ports are each a passage having a generally circular cross sections.
4. The improvement of claim 2 wherein said plurality of auxiliary ports is eight and said ports are generally uni-formly distributed about said central plasma passageway.
5. The improvement of claim 1 wherein said cooling liquid flow through said auxiliary ports is in the range of 20% to 50% of the total water flow through said nozzle.
6. In the method of initially positioning a plasma arc cutting torch relative to a workpiece, the torch being of the type in which a swirling motion is imparted to an ionizable gas through which the arc takes place, the flow of ionizable gas being initiated while the torch is in a retracted position, the torch being advanced toward the workpiece, the advance being ter-minated in response to a sensed, aburpt change in the vortex pressure within the torch, and the torch having an internal passage system in its nozzle that conducts a cooling fluid through said nozzle, the improvement comprising providing a set of auxiliary ports each in fluid com-munication with said cooling passage system, and directing a stream of gas through said auxiliary ports while said torch is retracted from the workpiece to clear resi-dual cooling fluid from said nozzle prior to cutting.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/230,025 US4361748A (en) | 1981-01-30 | 1981-01-30 | Cooling and height sensing system for a plasma arc cutting tool |
| US230,025 | 1988-08-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1175111A true CA1175111A (en) | 1984-09-25 |
Family
ID=22863655
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000393702A Expired CA1175111A (en) | 1981-01-30 | 1982-01-07 | Cooling and height sensing system for a plasma arc cutting tool |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US4361748A (en) |
| JP (1) | JPS57142779A (en) |
| CA (1) | CA1175111A (en) |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4521666A (en) * | 1982-12-23 | 1985-06-04 | Union Carbide Corporation | Plasma arc torch |
| JPS6228084A (en) * | 1985-07-30 | 1987-02-06 | Akira Kanekawa | Plasma jet torch |
| US5120930A (en) * | 1988-06-07 | 1992-06-09 | Hypertherm, Inc. | Plasma arc torch with improved nozzle shield and step flow |
| US5132512A (en) * | 1988-06-07 | 1992-07-21 | Hypertherm, Inc. | Arc torch nozzle shield for plasma |
| US5396043A (en) * | 1988-06-07 | 1995-03-07 | Hypertherm, Inc. | Plasma arc cutting process and apparatus using an oxygen-rich gas shield |
| US4861962B1 (en) * | 1988-06-07 | 1996-07-16 | Hypertherm Inc | Nozzle shield for a plasma arc torch |
| US5208441A (en) * | 1991-04-29 | 1993-05-04 | Century Manufacturing Co. | Plasma arc ignition system |
| US5124525A (en) * | 1991-08-27 | 1992-06-23 | Esab Welding Products, Inc. | Plasma arc torch having improved nozzle assembly |
| US5317126A (en) * | 1992-01-14 | 1994-05-31 | Hypertherm, Inc. | Nozzle and method of operation for a plasma arc torch |
| US5977510A (en) * | 1998-04-27 | 1999-11-02 | Hypertherm, Inc. | Nozzle for a plasma arc torch with an exit orifice having an inlet radius and an extended length to diameter ratio |
| US6326583B1 (en) | 2000-03-31 | 2001-12-04 | Innerlogic, Inc. | Gas control system for a plasma arc torch |
| US6677551B2 (en) * | 1998-10-23 | 2004-01-13 | Innerlogic, Inc. | Process for operating a plasma arc torch |
| US6163009A (en) * | 1998-10-23 | 2000-12-19 | Innerlogic, Inc. | Process for operating a plasma arc torch |
| US6498317B2 (en) | 1998-10-23 | 2002-12-24 | Innerlogic, Inc. | Process for operating a plasma arc torch |
| US6096992A (en) * | 1999-01-29 | 2000-08-01 | The Esab Group, Inc. | Low current water injection nozzle and associated method |
| US6498316B1 (en) | 1999-10-25 | 2002-12-24 | Thermal Dynamics Corporation | Plasma torch and method for underwater cutting |
| DE202004021663U1 (en) * | 2004-10-08 | 2010-05-12 | Kjellberg Finsterwalde Plasma Und Maschinen Gmbh | plasma torch |
| WO2008090617A1 (en) * | 2007-01-25 | 2008-07-31 | Nissin Inc. | Method for generating atmospheric pressure plasma gas flow |
| US8931429B2 (en) * | 2008-05-05 | 2015-01-13 | United Technologies Corporation | Impingement part cooling |
| US8338740B2 (en) * | 2008-09-30 | 2012-12-25 | Hypertherm, Inc. | Nozzle with exposed vent passage |
| US9949356B2 (en) | 2012-07-11 | 2018-04-17 | Lincoln Global, Inc. | Electrode for a plasma arc cutting torch |
| US8904912B2 (en) | 2012-08-16 | 2014-12-09 | Omax Corporation | Control valves for waterjet systems and related devices, systems, and methods |
| US11554461B1 (en) | 2018-02-13 | 2023-01-17 | Omax Corporation | Articulating apparatus of a waterjet system and related technology |
| WO2021202390A1 (en) | 2020-03-30 | 2021-10-07 | Hypertherm, Inc. | Cylinder for a liquid jet pump with multi-functional interfacing longitudinal ends |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3204076A (en) * | 1962-10-04 | 1965-08-31 | Thermal Dynamics Corp | Electric arc torch |
| US3641308A (en) * | 1970-06-29 | 1972-02-08 | Chemetron Corp | Plasma arc torch having liquid laminar flow jet for arc constriction |
| US4203022A (en) * | 1977-10-31 | 1980-05-13 | Hypertherm, Incorporated | Method and apparatus for positioning a plasma arc cutting torch |
-
1981
- 1981-01-30 US US06/230,025 patent/US4361748A/en not_active Expired - Lifetime
-
1982
- 1982-01-07 CA CA000393702A patent/CA1175111A/en not_active Expired
- 1982-01-27 JP JP57010265A patent/JPS57142779A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0316231B2 (en) | 1991-03-05 |
| JPS57142779A (en) | 1982-09-03 |
| US4361748A (en) | 1982-11-30 |
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