EP2022300A2 - Plasma cutting device - Google Patents

Plasma cutting device

Info

Publication number
EP2022300A2
EP2022300A2 EP07734474A EP07734474A EP2022300A2 EP 2022300 A2 EP2022300 A2 EP 2022300A2 EP 07734474 A EP07734474 A EP 07734474A EP 07734474 A EP07734474 A EP 07734474A EP 2022300 A2 EP2022300 A2 EP 2022300A2
Authority
EP
European Patent Office
Prior art keywords
electrode
nozzle
stop means
shoulder
shoulder means
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.)
Withdrawn
Application number
EP07734474A
Other languages
German (de)
French (fr)
Inventor
Giorgio Bassi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tecmo SRL
Original Assignee
Tecmo SRL
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Tecmo SRL filed Critical Tecmo SRL
Publication of EP2022300A2 publication Critical patent/EP2022300A2/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • H05H1/3442—Cathodes with inserted tip
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • H05H1/3478—Geometrical details
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • H05H1/3489—Means for contact starting

Definitions

  • the present invention relates to devices for generating a plasma jet fit, for example, for cutting and in particular refers to a plasma cutting device with pneumatic contact striking, of torch type, which can be handled manually or can be associated with a robotized arm or with an automatic machine.
  • plasma torch devices equipped with an electrode and a nozzle, the first positioned in the second and both placed at respective electrical potentials.
  • the electrode and the nozzle are mutually separated by an interspace crossed by a gas flow, usually air flow, a part of which is fit to form the plasma jet coming out from a hole of the nozzle and fit for cutting metallic pieces placed at a different electrical potential.
  • the jet striking is provoked by pneumatic actuating means that, translating the electrode from a contact condition with the nozzle to a separation condition from this latter, make an electric sparkle in the gas flow between the electrode and the nozzle.
  • the contact between the electrode and the nozzle occurs in correspondence of the inner end of the hole made in the nozzle for the plasma exit.
  • the nozzle and its plasma hole are protected from the destructive effect of the plasma from a layer constituted by a second gas portion, which is not ionized, and interposed between the jet and the hole wall, by protecting it.
  • a drawback of said known devices with contact pneumatic striking consists in that the striking sparkles rapidly cause deformations and irregularities of the surface of the nozzle adjacent to the inner end of the nozzle hole for the plasma; such deformations and irregularities provoke perturbations of the protection flow constituted by the second part of the air provoking the premature wear of the nozzle and deviations and/or instability of the plasma dart trajectory.
  • a further drawback of said known devices consists in that, in order to partially compensate the thermal excesses caused, as an example, by the perturbations and irregularity of the plasma dart, they are equipped with nozzles and electrodes realized with wide thickness and large amount of material provoking weight increases, encumbrances, costs and counter-productive thermal conduction towards inner parts of the known devices.
  • An object of the present invention is to propose a plasma cutting device in which the contact striking does not compromise the surface regularity of the nozzle near to the hole and does not cause any damn and premature wear of the same nozzle and its contiguous parts.
  • Another object is to propose a device that can be cooled also when the plasma dart is switched off.
  • a further object is to propose a device light, with little encumbrance and whose inner portions are not overheated.
  • Another object is to propose a device very efficient and having a low air or gas consumption.
  • figures 1 and 2 illustrate schematic views partially sectioned of a nozzle and an electrode of the plasma cutting device object of the present invention respectively in a rest condition and an operational condition;
  • FIG. 3 and 4 illustrate schematic views partially sectioned of a first variant of the device of figures 1 and 2 at the same rest and operational conditions and;
  • figures 5 and 6 illustrate schematic views partially sectioned of a second variant of the device of figures 1 and 2 at the same rest and operational conditions and;
  • - figures 7 and 8 illustrate schematic views partially sectioned of a third variant of the device of figures 1 and 2 at the same operational and rest conditions.
  • the device 1 has an hollow nozzle 3, equipped of a passing hole 4 for the plasma exit obtained from the ionization of flow gas portion, for instance air, flowing into the cavity.
  • an electrode 2 is housed, placed to a different electrical potential with respect to the nozzle, and moved by a translation means, not illustrated being known as an example with pneumatic piston, between a rest condition R and an operational condition O in which the electrode 2 and the nozzle 3 is respectively in contact and spaced.
  • a translation means not illustrated being known as an example with pneumatic piston
  • the diameter DTE of the end portion of the electrode 2 is comprised between 2 and 15 ; times, preferably approximately 7,5 times the minimal dimension M of hole 4 and the diameter DTC of the end portion of the nozzle cavity 3 is comprised between 3 and 20 times, preferably approximately 9 times, the minimal dimension M of hole 4.
  • the length LE of the electrode 2 is comprised between 1,5 and 11 times its own end diameter DTE and the length LC of the nozzle cavity 3 is comprised between 1,5 and 11 times its own end diameter DTC; in particular such lengths of the device of figures 1 and 2 are equal to approximately 2,5 - 3 times the respective end diameters.
  • the electrode 2 and the nozzle 3 are equipped with stop means respectively first 5 and second 6 specifically fit to realize the mutual contact between the electrode 2 and the nozzle 3 at the rest condition R.
  • Said stop means first 5 and second 6 are positioned, in the operational condition O, at a minimal distance D from the passing hole 4 equal at least two times the minimal dimension M of the hole.
  • the stop means first 5 and second 6 are placed on the cylindrical side surfaces external of the electrode 2 and internal of the nozzle 3 at a distance from the plasma hole 4 equal at least 6 times said minimal dimension M of the hole that is at a distance approximately equal to at least the end diameter of the electrode 2.
  • the invention provides that minimal distance DME between the first stop means 5 and the end extremity of the electrode 2 is comprised between 1/20 and 19/20 of the length LE of the electrode 2 and that the minimal distance DMC between the second stop means 6 and the end extremity of the nozzle cavity 3 is comprised between 1/20 and 19/20 of the length LC of the nozzle cavity 3.
  • the stop means first 5 and second 6 comprise respective shoulder means 7, 8 fit for mutually matching at the rest condition R in order to realize, in such condition, the contact between the electrode 2 and the nozzle 3.
  • the shoulder means 7, 8 of the stop means 5, 6, are shaped as circular crown or truncated- conical wall.
  • the shoulder means 7, 8 of the stop means 5, 6 preferably have the same shape of truncated conical wall with respective solid angles A, B having almost the same value.
  • the invention provides that such solid angles can be different, as an example the solid angle A of the shoulder means 7 of the electrode can be smaller than the other B.
  • the shape of shoulder means 7, 8 can be different, as an example ogival, polyhedric with spherical or curve sector surface.
  • the solid angles A, B defined by shoulder means first 7 and second 8 are comprised between 40° and 180° and preferably, as in the embodiment illustrated in figure 1 and 2, they are approximately equal and like to approximately 90°. Said angles A, B have a common bisectrix almost coinciding with the longitudinal axis of the electrode and the nozzle.
  • the shoulder means 7 of the first stop means 5 form a narrowing of the electrode 2 diameter in the direction of the gas flow and the shoulder means 8 of second stop means 6 form a narrowing of the nozzle cavity 3.
  • electrode 2 Starting from the end extremity and proceeding towards the direction opposite to the gas flow, electrode 2 has a cylindrical end portion with smoothed edge, the truncated-conical shoulder means 7 with apex towards the flow direction, a portion 9 of approximately cylindrical shape with diameter greater with respect to that end cylindrical downstream to the shoulder means 7, a portion of the approximately truncated conical shape 11 with apex upstream to the flow and joined together with a further approximately cylindrical shaped portion 12 ending with a screw connection for the translation means.
  • the nozzle cavity 3 has a cylindrical end portion with smoothed edge, the corresponding truncated conical shoulder means 8 with apex towards the flow direction, and a cylindrical portion 10 having a diameter greater than the end portion provided with a removable connection to the device.
  • the electrode 2 and the nozzle 3 have corresponding lightening 13, 14, consisting in concave lateral zones of material removal, fit to reduce the device weight and to reduce the propagation of the heat from the zone of formation of the dart towards the other device parts.
  • the stop means first 5 and second 6, with the corresponding shoulder means 7, 8, are obtained, as an example by turning, in a single body respectively with the electrode 2 and the nozzle 3.
  • the invention provides that one or both stop means first 5 and second 6 are constituted by one or more elements protruding to the outside of the electrode 2 and to the inside of the nozzle 3 and irremovably fixed thereto or, preferably, removably for its substitution.
  • the invention provides that at least one of shoulder means 7, 8 of stop means first second 5 and/or 6 is equipped with grooves or relieves, not illustrated, fit to allow the gas flow also in the rest condition R allowing the cooling of the electrode and the nozzle also in such condition therefore avoiding the risk of thermal excesses.
  • the relieves can eventually be conformed to facilitate the formation of the plasma spark and are disposed radially or tilted to an helicoidal gas flow.
  • the operation of device 1 provides that the superficial damages of the electrode and the nozzle in the formation zone of the sparkles for the plasma primer are distributed on wide surface and are far from the plasma hole.
  • the end portion of the electrode 2 is cylindrical portion shaped with rounded edge as in the embodiment of figures 1 and 2 while the end portion of the nozzle cavity 3 is approximately ogival or conical shaped in order to facilitate the restoration of the correct regular gas flow.
  • the variant of figures 5 and 6 of the device 1 differs for the greater length of the electrode and the nozzle that are equal to approximately 4 - 5 times the corresponding diameters.
  • the variant of the figures 7 and 8 of the device 1 differs for the smaller length of the electrode and the nozzle that are equal to approximately 1,5 - 2 times the respective diameters.
  • An advantage of the present invention is to supply a plasma cutting device with contact striking having a nozzle and an electrode of long duration and virtually free from perturbation and instability of the plasma dart.
  • Another advantage is to supply a light, small size device and whose inner portions are not overheated.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Geometry (AREA)
  • Plasma Technology (AREA)
  • Arc Welding In General (AREA)

Abstract

A plasma cutting device with pneumatic contact striking, supplied of at least an hollow nozzle (3) having a passing hole (4) for the plasma exit obtained from a gas flow that flow into the cavity in which is housed an electrode (2) moved by a translation means between a rest condition (R) and an operational condition (O) in which the electrode (2) and the nozzle (3) are respectively in contact and spaced. The electrode (2) and the nozzle (3) are equipped with stop means respectively first (5) and second (6) spaced to realize the mutual contact between the electrode (2) and the nozzle (3) in the rest condition (R). The electrode (2) and the nozzle (3) are positioned, in the operational condition (O), at a distance (D) from the passing hole (4) equal at least two times the minimal dimension (M) of such passing hole (4).

Description

PLASMA CUTTING DEVICE
TECHNICAL FIELD
The present invention relates to devices for generating a plasma jet fit, for example, for cutting and in particular refers to a plasma cutting device with pneumatic contact striking, of torch type, which can be handled manually or can be associated with a robotized arm or with an automatic machine.
BACKGROUND ART
There are known plasma torch devices equipped with an electrode and a nozzle, the first positioned in the second and both placed at respective electrical potentials. In an operational condition, the electrode and the nozzle are mutually separated by an interspace crossed by a gas flow, usually air flow, a part of which is fit to form the plasma jet coming out from a hole of the nozzle and fit for cutting metallic pieces placed at a different electrical potential.
In the known pneumatic torches devices, the jet striking is provoked by pneumatic actuating means that, translating the electrode from a contact condition with the nozzle to a separation condition from this latter, make an electric sparkle in the gas flow between the electrode and the nozzle.
The contact between the electrode and the nozzle occurs in correspondence of the inner end of the hole made in the nozzle for the plasma exit. The nozzle and its plasma hole are protected from the destructive effect of the plasma from a layer constituted by a second gas portion, which is not ionized, and interposed between the jet and the hole wall, by protecting it.
A drawback of said known devices with contact pneumatic striking, consists in that the striking sparkles rapidly cause deformations and irregularities of the surface of the nozzle adjacent to the inner end of the nozzle hole for the plasma; such deformations and irregularities provoke perturbations of the protection flow constituted by the second part of the air provoking the premature wear of the nozzle and deviations and/or instability of the plasma dart trajectory.
Another drawback of said known torch devices with pneumatic striking, consists in that their extinction involves the interruption of the gas or air flow through the nozzle hole, causing increases of temperature in some portions of the device accelerating the wear and the aging.
A further drawback of said known devices consists in that, in order to partially compensate the thermal excesses caused, as an example, by the perturbations and irregularity of the plasma dart, they are equipped with nozzles and electrodes realized with wide thickness and large amount of material provoking weight increases, encumbrances, costs and counter-productive thermal conduction towards inner parts of the known devices.
DISCLOSURE OF THE INVENTION
An object of the present invention is to propose a plasma cutting device in which the contact striking does not compromise the surface regularity of the nozzle near to the hole and does not cause any damn and premature wear of the same nozzle and its contiguous parts.
Other object is to propose a device that can be cooled also when the plasma dart is switched off.
A further object is to propose a device light, with little encumbrance and whose inner portions are not overheated.
Other object is to propose a device very efficient and having a low air or gas consumption.
The above mentioned objects are obtained according to the content of the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The characteristics of the present invention are evidenced in the following with particular reference to the attached drawings, in which: figures 1 and 2 illustrate schematic views partially sectioned of a nozzle and an electrode of the plasma cutting device object of the present invention respectively in a rest condition and an operational condition;
- figures 3 and 4 illustrate schematic views partially sectioned of a first variant of the device of figures 1 and 2 at the same rest and operational conditions and; figures 5 and 6 illustrate schematic views partially sectioned of a second variant of the device of figures 1 and 2 at the same rest and operational conditions and; - figures 7 and 8 illustrate schematic views partially sectioned of a third variant of the device of figures 1 and 2 at the same operational and rest conditions.
BEST MODE OF CARRYING OUT THE INVENTION
With reference to figures 1 and 2, 1 indicated the plasma cutting device with pneumatic contact striking, object of the present invention.
The device 1 has an hollow nozzle 3, equipped of a passing hole 4 for the plasma exit obtained from the ionization of flow gas portion, for instance air, flowing into the cavity.
In the nozzle cavity, an electrode 2 is housed, placed to a different electrical potential with respect to the nozzle, and moved by a translation means, not illustrated being known as an example with pneumatic piston, between a rest condition R and an operational condition O in which the electrode 2 and the nozzle 3 is respectively in contact and spaced.
The diameter DTE of the end portion of the electrode 2 is comprised between 2 and 15; times, preferably approximately 7,5 times the minimal dimension M of hole 4 and the diameter DTC of the end portion of the nozzle cavity 3 is comprised between 3 and 20 times, preferably approximately 9 times, the minimal dimension M of hole 4. The length LE of the electrode 2 is comprised between 1,5 and 11 times its own end diameter DTE and the length LC of the nozzle cavity 3 is comprised between 1,5 and 11 times its own end diameter DTC; in particular such lengths of the device of figures 1 and 2 are equal to approximately 2,5 - 3 times the respective end diameters.
The electrode 2 and the nozzle 3 are equipped with stop means respectively first 5 and second 6 specifically fit to realize the mutual contact between the electrode 2 and the nozzle 3 at the rest condition R.
Said stop means first 5 and second 6 are positioned, in the operational condition O, at a minimal distance D from the passing hole 4 equal at least two times the minimal dimension M of the hole. Preferably the stop means first 5 and second 6 are placed on the cylindrical side surfaces external of the electrode 2 and internal of the nozzle 3 at a distance from the plasma hole 4 equal at least 6 times said minimal dimension M of the hole that is at a distance approximately equal to at least the end diameter of the electrode 2. More in general, the invention provides that minimal distance DME between the first stop means 5 and the end extremity of the electrode 2 is comprised between 1/20 and 19/20 of the length LE of the electrode 2 and that the minimal distance DMC between the second stop means 6 and the end extremity of the nozzle cavity 3 is comprised between 1/20 and 19/20 of the length LC of the nozzle cavity 3.
The stop means first 5 and second 6 comprise respective shoulder means 7, 8 fit for mutually matching at the rest condition R in order to realize, in such condition, the contact between the electrode 2 and the nozzle 3.
The shoulder means 7, 8 of the stop means 5, 6, are shaped as circular crown or truncated- conical wall.
The shoulder means 7, 8 of the stop means 5, 6 preferably have the same shape of truncated conical wall with respective solid angles A, B having almost the same value. In alternative the invention provides that such solid angles can be different, as an example the solid angle A of the shoulder means 7 of the electrode can be smaller than the other B. Furthermore the invention provides in alternative that the shape of shoulder means 7, 8 can be different, as an example ogival, polyhedric with spherical or curve sector surface.
The solid angles A, B defined by shoulder means first 7 and second 8 are comprised between 40° and 180° and preferably, as in the embodiment illustrated in figure 1 and 2, they are approximately equal and like to approximately 90°. Said angles A, B have a common bisectrix almost coinciding with the longitudinal axis of the electrode and the nozzle.
The shoulder means 7 of the first stop means 5 form a narrowing of the electrode 2 diameter in the direction of the gas flow and the shoulder means 8 of second stop means 6 form a narrowing of the nozzle cavity 3.
Starting from the end extremity and proceeding towards the direction opposite to the gas flow, electrode 2 has a cylindrical end portion with smoothed edge, the truncated-conical shoulder means 7 with apex towards the flow direction, a portion 9 of approximately cylindrical shape with diameter greater with respect to that end cylindrical downstream to the shoulder means 7, a portion of the approximately truncated conical shape 11 with apex upstream to the flow and joined together with a further approximately cylindrical shaped portion 12 ending with a screw connection for the translation means.
Starting from the extremity inner end and proceeding towards the direction opposite to the gas flow, the nozzle cavity 3 has a cylindrical end portion with smoothed edge, the corresponding truncated conical shoulder means 8 with apex towards the flow direction, and a cylindrical portion 10 having a diameter greater than the end portion provided with a removable connection to the device.
The electrode 2 and the nozzle 3 have corresponding lightening 13, 14, consisting in concave lateral zones of material removal, fit to reduce the device weight and to reduce the propagation of the heat from the zone of formation of the dart towards the other device parts.
The stop means first 5 and second 6, with the corresponding shoulder means 7, 8, are obtained, as an example by turning, in a single body respectively with the electrode 2 and the nozzle 3. In alternative the invention provides that one or both stop means first 5 and second 6 are constituted by one or more elements protruding to the outside of the electrode 2 and to the inside of the nozzle 3 and irremovably fixed thereto or, preferably, removably for its substitution.
Optionally the invention provides that at least one of shoulder means 7, 8 of stop means first second 5 and/or 6 is equipped with grooves or relieves, not illustrated, fit to allow the gas flow also in the rest condition R allowing the cooling of the electrode and the nozzle also in such condition therefore avoiding the risk of thermal excesses. The relieves can eventually be conformed to facilitate the formation of the plasma spark and are disposed radially or tilted to an helicoidal gas flow. The operation of device 1 provides that the superficial damages of the electrode and the nozzle in the formation zone of the sparkles for the plasma primer are distributed on wide surface and are far from the plasma hole.
In such a way the irregularity and the damages produced by the sparkles do not cause considerable perturbations of the flow in correspondence of the hole and do not provoke distortions and instability of the plasma dart.
In the variant of the device of figures 3 and 4 the end portion of the electrode 2 is cylindrical portion shaped with rounded edge as in the embodiment of figures 1 and 2 while the end portion of the nozzle cavity 3 is approximately ogival or conical shaped in order to facilitate the restoration of the correct regular gas flow.
The variant of figures 5 and 6 of the device 1 differs for the greater length of the electrode and the nozzle that are equal to approximately 4 - 5 times the corresponding diameters.
The variant of the figures 7 and 8 of the device 1 , differs for the smaller length of the electrode and the nozzle that are equal to approximately 1,5 - 2 times the respective diameters.
An advantage of the present invention is to supply a plasma cutting device with contact striking having a nozzle and an electrode of long duration and virtually free from perturbation and instability of the plasma dart.
Other advantage is to supply a device that can be cooled also when the plasma dart is extinguished.
Another advantage is to supply a light, small size device and whose inner portions are not overheated.
Other advantage is to supply a device a very efficient and having a low gas or air consumption.

Claims

1) Plasma cutting device with pneumatic contact striking, supplied of at least an hollow nozzle (3) having a passing hole (4) for the exit of the plasma obtained from a gas flow that flow in the cavity in which is housed an electrode (2) moved by a translation means between a rest condition (R) and an operational condition (O) in which the electrode (2) and the nozzle (3) are respectively in contact and spaced; the device (1) is characterized in that the electrode (2) and the nozzle (3) are equipped with stop means respectively first (5) and second (6) fit to realize the mutual contact between the electrode (2) and the nozzle (3) in the rest condition (R) and placed, in the operational condition (O), at a distance (D) from the passing hole (4) equal at least two times the minimal dimension (M) of such passing hole (4).
2) Device according to claim 1 characterized in that the lateral external surfaces of the electrode (2) and lateral internal surfaces of the nozzle (3) are approximately cylindrical shaped and that the stop means first (5) and second (6) are positioned on such lateral surfaces.
3) Device according to claim 1 or claim 2 characterized in that the stop means first (5) and second (6) comprise corresponding shoulder means (7, 8) respectively of the electrode (2) and the nozzle (3) and have a mutual matching in the rest condition (R).
4) Device according to claim 3 characterized in that the shoulder means (7, 8) of the stop means (5, 6), are circular crown or truncated-conical wall shaped.
5) Device according to claim 4 characterized in that the shoulder means (7, 8) of the stop means (5, 6) have the same truncated-conical wall shape with corresponding solid angles (A, B) having almost the same value.
6) Device according to claim 5 characterized in that the solid angles (A, B) defined by the shoulder means, first (7) and second ones (8),are comprised between 40° and 180° and that such angles have a common bisectrix almost coinciding with the longitudinal axis of the electrode and the nozzle.
7) Device according to claim 6 characterized in that the solid angles (A, B) are preferably of approximately 90°.
8) Device according to claim 4 or claim 6 characterized in that the shoulder means (7) of the first stop means (5) form a narrowing of the diameter of the electrode (2) in the direction of the gas flow and the shoulder means (8) of the second stop means (6) forms a narrowing of the nozzle cavity (3).
9) Device according to claim 8 characterized in that upwardly of the gas flow with respect to the shoulder means (7) of the first stop means (5) and to shoulder means (8) of the second stop means (6) the electrode (2) and the nozzle cavity (3) have portions (9, 10) of approximately cylindrical shape with greater diameters with respect to those downstream corresponding of the shoulder means (7, 8).
10) Device according to 8 claim or claim 9 characterized in that upstream the shoulder means (7) with respect to the gas flow of first stop means (5), the electrode (2) has a portion shape
(11) approximately truncated-conical with apex upstream and joined with another portion
(12) approximately cylindrical.
11) Device according to anyone one of the previous claims characterized in that the electrode (2) and the nozzle (3) have respective lightening (13, 14) fit at least to reduce the heat propagation.
12) Device according to anyone of the previous claims characterized in that the diameter (DTE) of the end portion of the electrode (2) is comprised between 2 and 15 times, preferably approximately 7,5 times the minimal dimension (M) of hole (4).
13) Device according to anyone of the previous claims characterized in that diameter (DTC) of the end portion of the nozzle cavity (3) is comprised between 3 and 20 times, preferably approximately 9 times the minimal dimension (M) of hole (4).
14) Device according to anyone of the previous claims characterized in that the length (LE) of the electrode (2) is comprised between 1 ,5 and 11 times its own end diameter (DTE) and the length (LC) of the nozzle cavity (3) is comprised between 1,5 and 11 its own end diameter (DTC). 15) Device according to anyone of the preceding claims characterized in that minimal distance (DME) between first stop means (5) and the end extremity of the electrode (2) is comprised between 1/20 and 19/20 of the length (LE) of the electrode (2) and minimal distance (DMC) between second stop means (6) and the end extremity of the nozzle cavity (3) is comprised between 1/20 and 19/20 of length (LC) of the nozzle cavity (3).
16) Device according to anyone of the previous claims characterized in that the end portions of the electrode (2) and the nozzle cavity (3) are cylindrical portion shaped with rounded edge.
17) Device according to anyone of the claims from 1 to 15 characterized in that the end portion of the electrode (2) are cylindrical portion shaped with rounded edge and the end portion of the nozzle cavity (3) is approximately conical or ogival shaped.
18) Device according to claim 3 characterized in that at least one of stop means first (5) and second (6) with the corresponding shoulder mean (7, 8) are obtained in a single body with the electrode (2) and/or the nozzle (3).
19) Device according to claim 3 characterized in that the stop means first (5) and second (6) with the corresponding shoulder means (7, 8) are obtained in single body with the electrode (2) and/or the nozzle (3).
20) Device according to claim 3 characterized in that at least one of shoulder means (7, 8) of stop means, first (5) and/or second (6), has grooves or relieves fit at least to allow the gas flow also in the rest condition.
21) Device according to claim 20 characterized in that the relieves or the grooves, of at least one of shoulder means (7, 8), are arranged radially or tilted according to an helicoidal gas flow.
22) Device according to claim 3 characterized in that the stop means first (5) and second (6) and the corresponding shoulder means (7, 8) are fixed respectively to the electrode (2) and the nozzle (3).
23) Device according to claim 22 characterized in that the stop means first (5) and second (6) and the corresponding shoulder means (7, 8) are constituted by one or more elements protruding to the outside of the electrode (2) and to the inside of the nozzle (3).
EP07734474A 2006-05-04 2007-05-03 Plasma cutting device Withdrawn EP2022300A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT000332A ITBO20060332A1 (en) 2006-05-04 2006-05-04 PLASMA CUTTING DEVICE
PCT/IB2007/001157 WO2007129194A2 (en) 2006-05-04 2007-05-03 Plasma cutting device

Publications (1)

Publication Number Publication Date
EP2022300A2 true EP2022300A2 (en) 2009-02-11

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP07734474A Withdrawn EP2022300A2 (en) 2006-05-04 2007-05-03 Plasma cutting device

Country Status (3)

Country Link
EP (1) EP2022300A2 (en)
IT (1) ITBO20060332A1 (en)
WO (1) WO2007129194A2 (en)

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US8513565B2 (en) * 2008-04-10 2013-08-20 Hypertherm, Inc. Nozzle head with increased shoulder thickness
US20120223058A1 (en) * 2009-11-04 2012-09-06 Kabushiki Kaisha Yaskawa Denki Non-consumable electrode type arc welding apparatus
US8901451B2 (en) 2011-08-19 2014-12-02 Illinois Tool Works Inc. Plasma torch and moveable electrode
US10743399B2 (en) 2014-09-16 2020-08-11 The Esab Group, Inc. Reducing restart cycle time of a plasma blow back torch for improved marking
IT201600081330A1 (en) * 2016-08-02 2018-02-02 Cebora Spa PLASMA TORCH WITH CONTACT IGNITION
EP4062717A1 (en) 2019-11-19 2022-09-28 Hypertherm, INC. Consumable designs for a plasma arc torch

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ITBO20060332A1 (en) 2007-11-05
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