US3627204A - Spray nozzle for plasma guns - Google Patents

Spray nozzle for plasma guns Download PDF

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US3627204A
US3627204A US834293A US3627204DA US3627204A US 3627204 A US3627204 A US 3627204A US 834293 A US834293 A US 834293A US 3627204D A US3627204D A US 3627204DA US 3627204 A US3627204 A US 3627204A
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Prior art keywords
nozzle
plasma
spray nozzle
plasma gases
flame
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US834293A
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Mille Stand
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Sealectro Corp
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Sealectro Corp
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    • 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
    • H05H1/42—Plasma torches using an arc with provisions for introducing materials into the plasma, e.g. powder, liquid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
    • B05B7/16—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed
    • B05B7/22—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed electrically, magnetically or electromagnetically, e.g. by arc
    • B05B7/222—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed electrically, magnetically or electromagnetically, e.g. by arc using an arc
    • B05B7/226—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed electrically, magnetically or electromagnetically, e.g. by arc using an arc the material being originally a particulate material
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
    • C23C4/134—Plasma spraying
    • 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
    • H05H1/3405—Arrangements for stabilising or constricting the arc, e.g. by an additional gas flow
    • 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
    • H05H1/3468—Vortex generators

Definitions

  • Plasma jets are formed by passing a gas under pressure through an electric are.
  • a stream of fluent powder is added to the plasma after it passes from the arc chamber but before it reaches the end of the nozzle. It has been found that ordinary nozzles cause the ejected flame to spread and, in many cases. to oscillate and exhibit other unstable characteristics. This causes an uneven coating of the sprayed-material and also uneven heating.
  • the above objections can'be overcome by the invention herein described.
  • the grooves provide the stabilizing effect necessary to confine the'flame and, in addition, to mix the fluent powder with the hot gases so that the powder temperature can be controlled and an even'integral coating of the material can be deposited on a substrate.
  • a feature of the invention is the provision of a plurality of helical grooves, having variable depth, which contain and stabilize the arc flame without the expenditure of any power and without the addition of mechanical motion.
  • FIG. 1 is a side view of the nozzle showing the helical grooves.
  • FIG. 2 is a cross-sectional view taken along an axial plane showing the conduits which add powdered material to the plasma.
  • FIG. 3 is an end view of the nozzle showing the groove ends and the relative location of the conduits which add the fluent material.
  • FIG. 4 is a cross section view (enlarged) of a portion of the nozzle showing the entrance means to the fluent material conduits and a method of producing a right angle bend in the conduit lines.
  • the nozzle is a generally cylindrical piece of high melting point metal having an axial conduit 11 for conveying and expelling the plasma.
  • an enlarged portion 13 houses an arc chamber where an electrical discharge is created between a first electrode 14 and the inside surface of the conduit. The are discharge heats and ionizes the gas flowing through the arc chamber and thereby creates a plasma.
  • the details of the arc discharge and the electrodes which support it are set forth in a patent application, Ser. No. 835,876, now US. Pat. No. 3,591,759, granted July 6, 1971 filed June 4, I969. These details of construction are not a part of this invention so will not be described here.
  • the fluent material which may be Teflon powder, is entered through two flexible tubes 15 and 16 secured to the outside of the nozzle and connected to a reservoir (not shown) under pressure.
  • the powdered material is forced into two conduits I7 and 18 disposed at an angle of about 20 to the nozzle axis. These conduits may be formed by drilling holes in the nozzle block starting from a position 20 on the other side of the rim 19 and then closing a portion of the hole with a plug 21.
  • the gas or mixture of gases which are forced through the arc chamber are given an initial helical directionvwhich causes the plasma to turn on its axis as it passes through and out of the nozzle. This action tends to mix the powder with the plasma in an even manner but only in the space near the gas surface. The centrifugal force of the gas motion also tends to keep the powder near the surface.
  • a series of helical grooves 22 are cut into the outside cylindrical surface of the nozzle I0 as shown in the fi area.
  • Each groove 22 starts near the rim I9 and has-a depth a ut equal to its width.
  • the grooves 22 con tinue around the surface of the nozzle, with increasing depth, until they terminate at the face of the nozzle (see FIG. 3), having a depth about three times their width.
  • the circular direction of the grooves must be the same as the circular motion of the plasma gas. That is, if the plasma is given a clockwise rotation, as viewed from the arc chamber, then the grooves must also be clockwise.
  • the heated gases expelled from the nozzle conduit 11 move at great speed and because of their velocity, create a reduced pressure nearthe nozzle face.
  • This reduced pressure draws air through the grooves 22 and from the atmosphere and, because they move in a helical direction, the air jets surround the plasma flame and prevent its spreading.
  • the air jets also protect the flame from outside movements of air and make the flame more stable.
  • four spaced helical grooves are shown, all having a variable depth. More grooves may be employed if desired.
  • the grooves function without the attention of the operator of the gun and need no adjustment. They consume no power, instead the indications are that less power is required to operate the gun when the grooves are used.
  • a spray nozzle for a plasma gun comprising; a cylindrical nozzle having an axial opening through which plasma gases are ejected, said nozzle having a flat end face disposed substantially perpendicular to the nozzle axis; said nozzle formed with a plurality of equally spaced helical grooves cut in the outside surface of the nozzle open to the atmosphere and terminating in the nozzle face for providing jets of air which surround and limit the plasma gases.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electromagnetism (AREA)
  • Nozzles (AREA)

Abstract

A spray nozzle having a series of helical grooves cut in the outside surface of the nozzle in order to shape and confine the flame ejected from the interior of the gun. The force of the flame draws air through the grooves and thereby provides a helical shield which prevents the flame from spreading and makes it more stable.

Description

United States Patent Inventor Mllle Stand New York. N.Y. Appl. No. 834,293 Filed June 18, 1969 Patented Dec. 14, 1971 Assignee Sealectro Corporation Marnaroneck, N.Y.
SPRAY NOZZLE FOR PLASMA GUNS 5 Claims, 4 Drawing Figs.
U.S. Cl 239/81, 117/931, 219/75, 239/291, 239/406, 239/424, I 239/488 Int. Cl B05b 7/10 Field 01 Search 239/81,
ll7/93.l;2l9/75, 121
llll 3,627,204
[56] Reierences Cited UNITED STATES PATENTS 3,47 l .675 10/1969 Sargent et al. 219/75 3,1 14,826 12/1963 Sullivan et al. 117/9341 UX 2,855,033 10/1958 Furczyk 239/406 3,405,926 6/1969 Kiernan 219/75 X Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Michael Y. Mar Attorney-James M. Heilmon ABSTRACT: A spray nozzle having a series of helical grooves cut in the outside surface of the nozzle in order to shape and confine the flame ejected from the interior of the gun. The force of the flame draws air through the grooves and thereby provides a helical shield which prevents the flame from spreading and makes it more stable.
PATENTEDUEIAMBTI 3,627,204
MILLE N JOHN P. H ND R H TTO Y.
SPRAY NOZZLE FOR PLASMA GUNS Plasma jets are formed by passing a gas under pressure through an electric are. In order to spray powdered material by means of the are, a stream of fluent powder is added to the plasma after it passes from the arc chamber but before it reaches the end of the nozzle. It has been found that ordinary nozzles cause the ejected flame to spread and, in many cases. to oscillate and exhibit other unstable characteristics. This causes an uneven coating of the sprayed-material and also uneven heating.
The above objections can'be overcome by the invention herein described. The grooves provide the stabilizing effect necessary to confine the'flame and, in addition, to mix the fluent powder with the hot gases so that the powder temperature can be controlled and an even'integral coating of the material can be deposited on a substrate.
A feature of the invention is the provision of a plurality of helical grooves, having variable depth, which contain and stabilize the arc flame without the expenditure of any power and without the addition of mechanical motion.
For a better understanding of the present invention, together with other details and features thereof, references is made to the following description taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the nozzle showing the helical grooves.
FIG. 2 is a cross-sectional view taken along an axial plane showing the conduits which add powdered material to the plasma. I
FIG. 3 is an end view of the nozzle showing the groove ends and the relative location of the conduits which add the fluent material.
FIG. 4 is a cross section view (enlarged) of a portion of the nozzle showing the entrance means to the fluent material conduits and a method of producing a right angle bend in the conduit lines.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the figures, the nozzle is a generally cylindrical piece of high melting point metal having an axial conduit 11 for conveying and expelling the plasma. At the entrance end of the conduit 11, an enlarged portion 13 houses an arc chamber where an electrical discharge is created between a first electrode 14 and the inside surface of the conduit. The are discharge heats and ionizes the gas flowing through the arc chamber and thereby creates a plasma. The details of the arc discharge and the electrodes which support it are set forth in a patent application, Ser. No. 835,876, now US. Pat. No. 3,591,759, granted July 6, 1971 filed June 4, I969. These details of construction are not a part of this invention so will not be described here.
The fluent material, which may be Teflon powder, is entered through two flexible tubes 15 and 16 secured to the outside of the nozzle and connected to a reservoir (not shown) under pressure. The powdered material is forced into two conduits I7 and 18 disposed at an angle of about 20 to the nozzle axis. These conduits may be formed by drilling holes in the nozzle block starting from a position 20 on the other side of the rim 19 and then closing a portion of the hole with a plug 21.
The gas or mixture of gases which are forced through the arc chamber are given an initial helical directionvwhich causes the plasma to turn on its axis as it passes through and out of the nozzle. This action tends to mix the powder with the plasma in an even manner but only in the space near the gas surface. The centrifugal force of the gas motion also tends to keep the powder near the surface.
To control the ejected gas' flame, a series of helical grooves 22 are cut into the outside cylindrical surface of the nozzle I0 as shown in the fi area. Each groove 22 starts near the rim I9 and has-a depth a ut equal to its width. The grooves 22 con tinue around the surface of the nozzle, with increasing depth, until they terminate at the face of the nozzle (see FIG. 3), having a depth about three times their width. The circular direction of the grooves must be the same as the circular motion of the plasma gas. That is, if the plasma is given a clockwise rotation, as viewed from the arc chamber, then the grooves must also be clockwise.
.When the gun is operated, the heated gases expelled from the nozzle conduit 11 move at great speed and because of their velocity, create a reduced pressure nearthe nozzle face. This reduced pressure draws air through the grooves 22 and from the atmosphere and, because they move in a helical direction, the air jets surround the plasma flame and prevent its spreading. The air jets also protect the flame from outside movements of air and make the flame more stable. In the drawings, four spaced helical grooves are shown, all having a variable depth. More grooves may be employed if desired. The grooves function without the attention of the operator of the gun and need no adjustment. They consume no power, instead the indications are that less power is required to operate the gun when the grooves are used.
The foregoing disclosure and drawings are merely illustrative of the principles of this invention and are not to be interpreted in a limiting sense. The only limitations are to be determined from the scope of the appended claims.
What is claimed is:
I. A spray nozzle for a plasma gun comprising; a cylindrical nozzle having an axial opening through which plasma gases are ejected, said nozzle having a flat end face disposed substantially perpendicular to the nozzle axis; said nozzle formed with a plurality of equally spaced helical grooves cut in the outside surface of the nozzle open to the atmosphere and terminating in the nozzle face for providing jets of air which surround and limit the plasma gases.
2. A spray nozzle as claimed in claim 1 wherein conduit means are provided in the nozzle for adding solid fluent material to the plasma for ejection with the plasma gases.
3. A spray nozzle as claimed in claim 1 wherein directive means are provided for giving the plasma gases a helical flow through the axial opening.
4. A spray nozzle as claimed in claim 1 wherein the helical grooves are formed with a depth which increases as the nozzle face is approached.
5. A spray nozzle as claimed in claim 1 wherein the axial opening is formed with an abrupt step in the opening diameter between two axial portions thereof for creating a turbulent flow and for mixing a quantity of solid fluent material into the plasma gases.
i l l I l

Claims (5)

1. A spray nozzle for a plasma gun comprising; a cylindrical nozzle having an axial opening through which plasma gases are ejected, said nozzle having a flat end face disposed substantially perpendicular to the nozzle axis; said nozzle formed with a plurality of equally spaced helical grooves cut in the outside surface of the nozzle open to the atmosphere and terminating in the nozzle face for providing jets of air which surround and limit the plasma gases.
2. A spray nozzle as claimed in claim 1 wherein conduit means are provided in the nozzle for adding solid fluent material to the plasma for ejection with the plasma gases.
3. A spray nozzle as claimed in claim 1 wherein directive means are provided for giving the plasma gases a helical flow through the axial opening.
4. A spray nozzle as claimed in claim 1 wherein the helical grooves are formed with a depth which increases as the nozzle face is approached.
5. A spray nozzle as claimed in claim 1 wherein the axial opening is formed with an abrupt step in the opening diameter between two axial portions thereof for creating a turbulent flow and for mixing a quantity of solid fluent material into the plasma gases.
US834293A 1969-06-18 1969-06-18 Spray nozzle for plasma guns Expired - Lifetime US3627204A (en)

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BE (1) BE771968A (en)
CH (1) CH531898A (en)
DE (1) DE2144873A1 (en)
FR (1) FR2151488A5 (en)
GB (1) GB1315917A (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3851140A (en) * 1973-03-01 1974-11-26 Kearns Tribune Corp Plasma spray gun and method for applying coatings on a substrate
US4548358A (en) * 1983-10-27 1985-10-22 Fischer Robert A Multiple piece cutting tip
US5285967A (en) * 1992-12-28 1994-02-15 The Weidman Company, Inc. High velocity thermal spray gun for spraying plastic coatings
US5833141A (en) * 1997-05-30 1998-11-10 General Electric Company Anti-coking dual-fuel nozzle for a gas turbine combustor
WO2004043639A1 (en) * 2002-11-12 2004-05-27 Plasma Laser Technologies Ltd. Mig-plasma welding
US20050082395A1 (en) * 2003-10-09 2005-04-21 Thomas Gardega Apparatus for thermal spray coating
US20060138252A1 (en) * 2004-12-16 2006-06-29 Keudell Leopold V Powder conveying device and catching nozzle for the powder conveying device
US20070074656A1 (en) * 2005-10-04 2007-04-05 Zhibo Zhao Non-clogging powder injector for a kinetic spray nozzle system

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2287276A1 (en) * 1974-10-07 1976-05-07 United Technologies Corp THERMAL SPRAYER AND METHOD OF SPRAYING USING THIS APPARATUS
DE102013010126B4 (en) * 2013-06-18 2015-12-31 Häuser & Co. GmbH Plasmapulverspritzverfahren and apparatus for coating panels for boiler walls in conjunction with a laser beam device

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3851140A (en) * 1973-03-01 1974-11-26 Kearns Tribune Corp Plasma spray gun and method for applying coatings on a substrate
US4548358A (en) * 1983-10-27 1985-10-22 Fischer Robert A Multiple piece cutting tip
US5285967A (en) * 1992-12-28 1994-02-15 The Weidman Company, Inc. High velocity thermal spray gun for spraying plastic coatings
US5833141A (en) * 1997-05-30 1998-11-10 General Electric Company Anti-coking dual-fuel nozzle for a gas turbine combustor
WO2004043639A1 (en) * 2002-11-12 2004-05-27 Plasma Laser Technologies Ltd. Mig-plasma welding
US20050082395A1 (en) * 2003-10-09 2005-04-21 Thomas Gardega Apparatus for thermal spray coating
US7216814B2 (en) 2003-10-09 2007-05-15 Xiom Corp. Apparatus for thermal spray coating
US20060138252A1 (en) * 2004-12-16 2006-06-29 Keudell Leopold V Powder conveying device and catching nozzle for the powder conveying device
US7530505B2 (en) * 2004-12-16 2009-05-12 J. Wagner Ag Powder conveying device and catching nozzle for the powder conveying device
US20070074656A1 (en) * 2005-10-04 2007-04-05 Zhibo Zhao Non-clogging powder injector for a kinetic spray nozzle system

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Publication number Publication date
CH531898A (en) 1972-12-31
GB1315917A (en) 1973-05-09
BE771968A (en) 1971-12-31
FR2151488A5 (en) 1973-04-20
DE2144873A1 (en) 1973-03-15

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