GB2144654A - Thermal spraying gun nozzle - Google Patents
Thermal spraying gun nozzle Download PDFInfo
- Publication number
- GB2144654A GB2144654A GB08413633A GB8413633A GB2144654A GB 2144654 A GB2144654 A GB 2144654A GB 08413633 A GB08413633 A GB 08413633A GB 8413633 A GB8413633 A GB 8413633A GB 2144654 A GB2144654 A GB 2144654A
- Authority
- GB
- United Kingdom
- Prior art keywords
- nozzle
- gas
- ejecting
- bushing
- mixed gas
- 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- Withdrawn
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
- H05H1/42—Plasma torches using an arc with provisions for introducing materials into the plasma, e.g. powder, liquid
-
- 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
-
- 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
- B05B7/02—Spray pistols; Apparatus for discharge
- B05B7/08—Spray pistols; Apparatus for discharge with separate outlet orifices, e.g. to form parallel jets, i.e. the axis of the jets being parallel, to form intersecting jets, i.e. the axis of the jets converging but not necessarily intersecting at a point
-
- 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
- B05B7/20—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 by flame or combustion
- B05B7/201—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 by flame or combustion downstream of the nozzle
- B05B7/205—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 by flame or combustion downstream of the nozzle the material to be sprayed being originally a particulate material
-
- 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
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Geometry (AREA)
- Nozzles (AREA)
Abstract
A nozzle of a thermal spraying gun for plastic comprises a material ejecting nozzle 1 having a supply port 1a for supplying and ejecting a plastic material, a gas ejecting nozzle 2 having a nozzle head 2b with plural gas ejecting holes 2d for ejecting the mixed gas of air and propane gas and being attached concentrically to the material ejecting nozzle 1, an air passage gap being maintained between the nozzles 1 and 2 to form an air curtain around the plastic material, a bushing 3 concentrically attached to the nozzle 2, and a hood 4 attached to the front portion of the bushing so as to surround the front space of the gas ejecting nozzle 2, part of the mixed gas being leaked from plural pilot holes 2e made in the nozzle head 2b for reducing the velocity of flow of the part of the gas, the part of mixed gas with the reduced velocity being supplied to the base portion of flow of the mixed gas ejected from the gas ejecting holes 2d. <IMAGE>
Description
SPECIFICATION
Nozzle of Thermal Spraying Gun for Plastic
Field of the Invention
The present invention relates to nozzles of thermal spraying guns for plastic materials, and more particularly to nozzles of thermal spraying guns for forming plastic coats on the surface of large steel structures for the corrosion prevention, electrical insulation, improvement of wear resistance or decorative purpose.
Description of the Prior Art
Conventionally various kinds of nozzles of this type of thermal spraying guns for plastic were available and an example of the nozzle is shown in
Fig. 4. Shown in Fig. 4 are a nozzle holder 11, a bushing 12 attached to the tip opening of the nozzle holder 1 1, a gas ejecting nozzle 13, a material ejecting nozzle 14, a supply port 14a for plastic materials such as plastic particulate matters and particulates of paste solution, a supply port 1 a for a mixed gas to form a flame, and a supply port 1 b for air. However, this nozzle will be attached to the discharge opening of a thermal spraying gun (not shown in the figure) by fixing the nozzle holder 11 with screws.
When using this gun, a plastic material ejected forward from the body side of the thermal spraying gun through the supply port 1 4a is surrounded by an air curtain discharged from a slit 1 5 located between the tip portion of the material ejecting nozzle 14 and the tip portion of the gas ejecting nozzle 13, the outer side of the air curtain is surrounded by said mixed gas forcibly ejected from a slit 1 6 located between the tip portion of the gas ejecting nozzle 13 and the tip portion of the bushing 12, the mixed gas is ignited, and then the plastic material melted by a flame through the air curtain is sprayed upon the surface of work to be coated such as metal plate. In this case, the air curtain is used to prevent the plastic material from being burned before it reaches the surface of work to be coated.
However, in this kind of thermal spraying gun for plastic, normally a mixture of oxygen and propane gas is used so that the temperature of flame becomes excessively higher than necessary (such as 2,8000C), thereby resulting such shortcomings as decomposition, deterioration or burning of the plastic material. Also, there are other shortcomings such as expensive cost of oxygen gas, and troublesome operation in procuring, transporting and replacing oxygen bombs. The present invention has been made to eliminate these shortcomings explained above.
Brief Description of the Invention
Object of the present invention is to provide a nozzle of thermal spraying gun for plastic which allows the use of a mixture of air and propane gas for eliminating various shortcomings resulted from the conventional use of oxygen, improving the workability and reducing costs, and assures a stable flame with the optimum temperature suited to the thermal spraying of plastic.
The present invention is a nozzle of thermal spraying gun comprising a material ejecting nozzle, a gas ejecting nozzle having a hat-shaped nozzle head with plural gas ejecting holes and pilot holes for ejecting the mixed gas of air and propane gas and being attached concentrically to said material ejecting nozzle with an air passage gap maintained between said material ejecting nozzle and gas ejecting nozzle, a bushing concentrically attached to said gas ejecting nozzle, and a hood attached to the front portion of said bushing so as to surround the front space of said gas ejecting nozzle.
Brief Description of the Drawings
Figs. 1, 2 and 3 shows a preferred embodiment of the invention, Fig. 1 shows a longitudinal section of the nozzle. Fig. 2 shows a partial longitudinal section of the gas ejecting nozzle, Fig.
3 shows the front view of the partial longitudinal section shown in Fig. 2, and Fig. 4 is a longitudinal section of a nozzle as an example of prior art.
Detailed Description of the Invention
The present invention comprises a material ejecting nozzle 1, a gas ejecting nozzle 2, a bushing 3, a hood 4 and a nozzle holder 5. The material ejecting nozzle 1 has a cylindrical shape having a supply port 1 a for plastic material as same as conventional nozzle, and a mounting thread 1 b to the nozzle holder 5 is formed at the rear end of the nozzle in the axial direction. Also, plural projections 1 c for positioning are formed on the outer perimeter of the material ejecting nozzle 1 at a location almost at the center but slightly closer to the front in the direction of length of the nozzle, and air will pass through the slit provided between these projections.
The gas ejecting nozzle 2 has a barrel portion 2a of almost cylindrical shape into which the material injecting nozzle 1 can be inserted as shown in Figs. 2 and 3 in detail, a nozzle head 2b of almost hat shape is formed around the tip of the barrel portion 2a, a void 2c is formed between the nozzle head 2b and the tip of the barrel portion 2a, and many gas ejecting holes 2d are made on the tip face of the nozzle head 2b in the circumferential direction. Also, on the side face of the nozzle head 2b, plural pilot holes 2e (for example, 8 holes) are made with a proper spacing along the whole perimeter. These pilot holes 2e are made into the void 2c in the direction perpendicular to the axis of the barrel portion 2a, and a desired diameter of this hole is about 0.7 mm.
The bushing 3 has a through hole 3a which is fitted to and inscribes the rear end of the nozzle head 2b as shown in Fig. 1 and also has a collar 3b for attaching the hood 4 to the front end of the bushing in the axial direction and a collar 3c for attaching the nozzle holder 5 at the rear end.
Also, the cylindrical hood 4 is screwed to the collar 3b of the bushing 3, and plural through holes 4a for cooling are made on the outer perimeter of this hood 4.
In addition, a supply port 5a for the mixed gas of air and propane gas and a supply port 5b for air are made in the nozzle holder 5 attached to a discharge opening M of the body of thermal spraying gun with screws or the like, and also a through hole to the supply port 1 a of the material ejecting nozzle 1 is made in the holder. Also, a thread is formed on the inner perimeter of the tip portion of the nozzle holder 5 for attaching the collar 3c of the bushing 3.
For assembling these parts together, the material ejecting nozzle 1 is screwed to the nozzle holder 5, the gas ejecting nozzle 2 is placed concentrically around the material ejecting nozzle 1, the bushing 3 is screwed to the nozzle holder 5 while inserting the nozzle head 2b into the through hole 3a of the bushing 3, and then the hood 4 is attached to the collar 3b of the bushing 3. It is required to maintain a small gap for air flow between the tip portion of the material ejecting nozzle 1 and the tip portion of the gas ejecting nozzle 2, and also the pilot holes 2e of the nozzle head 2b projected out from the through hole 3a of the bushing 3 must open to the inner space of the collar 3b.
Now the operation of this nozzle will be explained. As shown in Fig. 1 , the mixed gas consisting of air and propane gas with a proper air to gas ratio as well as air are forcibly supplied through pipes from the inside of the discharge opening M of the body of thermal spraying gun to the supply ports 5a and 5b respectively. Then, the mixed gas F is discharged from the gas ejecting holes 2d, and part of said mixed gas, F', leaks out near the nozzle head 2b from the pilot holes 2e of the nozzle head 2b. The mixed gas F ejected from the gas ejecting holes 2d has a high speed, but the mixed gas F' leaked from the pilot holes 2e collides with the collar 3b and thus the speed of the flow of the mixed gas F' is considerably reduced.Then, this flow collides with the base portion of the flow of mixed gas F and thus the speed of the mixed gas F is so reduced that a stable flame which is not easily extinguishable can be obtained after the ignition of the gas.
The flame produced as a result of the ignition of the mixed gas F comes to the surface of a work to be coated such as metal plate while maintaining a temperature sufficient for melting the plastic and then heats the surface.
Then, if a plastic material P is forcibly supplied through the supply port 1 a, this plastic material P is ejected forward from the tip of the material ejecting nozzle 1. In this case, the plastic material
P being ejected is surrounded by the air curtain A and thus is separated from the flame thereby preventing the material P from being deteriorated or burned. Because of this, the plastic material P in properly melted state collides at a high speed with the surface of a work and is adhered to the surface. Therefore, by uniformly spraying the plastic upon the surface of a work to be coated, a plastic coat can be formed throughout the whole surface of the work.Also, air for secondary combustion flows through the through hole 4a of the hood 4 and positively cools the hood 4 and bushing 3 and thus the temperature of the hood 4 and others can be so reduced that they can be held even by hand during work.
The present invention of the nozzle of thermal spraying gun for plastic stated above comprises a material ejecting nozzle having a supply port for supplying and ejecting a plastic material, a gas ejecting nozzle having a nozzle head with plural gas ejecting holes for ejecting the mixed gas of air and propane gas, and being attached concentrically to said material ejecting nozzle with an air passage gap maintained between said material ejecting nozzle and said gas ejecting nozzle, a bushing concentrically attached to said gas ejecting nozzle, and a hood attached to the front portion of said bushing so as to surround the front space of said gas ejecting nozzle, part of said mixed gas being leaked from plural pilot holes made in said nozzle head for reducing the velocity of flow of the part of said mixed gas, said part of mixed gas with the reduced velocity being supplied to the base portion of flow of said mixed gas ejected from said gas ejecting holes.
Therefore, by using the mixed gas of air and propane gas, a flame with a necessary, sufficient temperature for melting the plastic material can be obtained so that the nozzle of the present invention is effective for preventing the plastic material from being deteriorated or burned by a flame of an excessively high temperature as seen in the case of conventional nozzles.
Also, since air is employed instead of oxygen gas of conventional method, costs can be reduced, troublesome work for procuring and replacing oxygen bombs can be eliminated, and the thermal spraying work can be performed in any remote areas where the oxygen gas is not available.
Another effect of the present invention is that a stable flame which cannot be easily extinguished can be obtained because part of the mixed gas leaking from the pilot holes reduces the velocity of flow of the main mixed gas from the gas ejecting holes.
Claims (5)
1. A nozzle of thermal spraying gun for plastic comprising a material ejecting nozzle having a supply port for supplying and ejecting a plastic material, a gas ejecting nozzle having a nozzle head with plural gas ejecting holes for ejecting the mixed gas of air and propane gas and being attached concentrically to said material ejecting nozzle with an air passage gap maintained between said material ejecting nozzle and gas ejecting nozzle, a bushing concentrically attached to said gas ejecting nozzle, and a hood attached to the front portion of said bushing so as to surround the front space of said gas ejecting nozzle, part of said mixed gas being leaked from plural pilot holes made in said nozzle head for reducing the velocity of flow of the part of said mixed gas, said part of mixed gas with the reduced velocity being supplied to the base portion of flow of said mixed gas ejected from said gas ejecting holes.
2. A nozzle of thermal spraying gun for plastic comprising a cylindrical material ejecting nozzle, a gas ejecting nozzle, a bushing position concentrically and outwardly from the center together with said material ejecting nozzle and said gas ejecting nozzle, an air ejecting gap provided between said material ejecting nozzle and said gas ejecting nozzle, a passage for the mixed gas of air and propane gas provided between said gas ejecting nozzle and said bushing, a hat-shaped nozzle head concentrically attached to the tip and outer periphery of said gas ejecting nozzle at the tip of said passage for mixed gas, gas ejecting holes made through the front face of said nozzle head, pilot holes made through the peripheral face of said nozzle head, and a void provided inside of said nozzle head.
3. A nozzle of thermal spraying gun for plastic of claim 1 or 2, the tip of said bushing being attached to a cylindrical hood having plural through holes to the outer periphery of said hood.
4. A nozzle of thermal spraying gun for plastic of claim 2, said gas ejecting holes and pilot holes respectively being made and connected to said void provided inside said nozzle head.
5. A nozzle of thermal spraying gun for plastic of claim 2, the outlets of said pilot holes being connected to a space provided inside of a collar formed at the tip of said bushing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1983096250U JPS605464U (en) | 1983-06-22 | 1983-06-22 | Plastic spray gun crater |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8413633D0 GB8413633D0 (en) | 1984-07-04 |
| GB2144654A true GB2144654A (en) | 1985-03-13 |
Family
ID=14159964
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08413633A Withdrawn GB2144654A (en) | 1983-06-22 | 1984-05-29 | Thermal spraying gun nozzle |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS605464U (en) |
| DE (1) | DE3422904A1 (en) |
| FR (1) | FR2548926A1 (en) |
| GB (1) | GB2144654A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0513497A1 (en) * | 1991-05-08 | 1992-11-19 | Plasma-Technik Ag | High-velocity thermal spray apparatus |
| ITBO20090292A1 (en) * | 2009-05-08 | 2010-11-09 | Ibix Srl | METHOD AND EQUIPMENT FOR FLAME SPRAYING OF THERMOPLASTIC POWDERS |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2671292B1 (en) * | 1991-01-03 | 1995-03-24 | Air Liquide | NOZZLE AND GUN FOR THERMAL SPRAYING OF PLASTIC MATERIAL. |
-
1983
- 1983-06-22 JP JP1983096250U patent/JPS605464U/en active Granted
-
1984
- 1984-05-29 GB GB08413633A patent/GB2144654A/en not_active Withdrawn
- 1984-06-20 DE DE19843422904 patent/DE3422904A1/en not_active Withdrawn
- 1984-06-20 FR FR8409649A patent/FR2548926A1/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0513497A1 (en) * | 1991-05-08 | 1992-11-19 | Plasma-Technik Ag | High-velocity thermal spray apparatus |
| ITBO20090292A1 (en) * | 2009-05-08 | 2010-11-09 | Ibix Srl | METHOD AND EQUIPMENT FOR FLAME SPRAYING OF THERMOPLASTIC POWDERS |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2548926A1 (en) | 1985-01-18 |
| JPS605464U (en) | 1985-01-16 |
| GB8413633D0 (en) | 1984-07-04 |
| JPS6331719Y2 (en) | 1988-08-24 |
| DE3422904A1 (en) | 1985-01-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |