Claims
- 1. In a process of flame plating with a detonation gun, the improvement wherein a gaseous fuel-oxidant mixture is used which comprises: (a) an oxidant and (b) a fuel mixture of at least two combustible gases selected from the group of saturated and unsaturated hydrocarbons and wherein the combustion temperature of the fuel mixture is lower than the combustion temperature of one of the combustible gases.
- 2. The process of claim 1 wherein said fuel mixture comprises a mixture of acetylene and a second combustible gas selected from the group consisting of propylene, methane, ethylene, methyl acetylene, propane, pentane, a butadiene, a butalene, a butane,
- 3. The process of claim 2 wherein said oxidant is selected from the group consisting of oxygen, nitrous oxide and mixtures thereof.
- 4. The process of claim 3 wherein said mixture has an atomic ratio of oxygen to carbon of from about 0.9 to about 2.0.
- 5. The process of claim 4 wherein said second combustible gas is selected from the group consisting of propylene, propane and a butylene and the atomic ratio of oxygen to carbon is from about 0.95 to about 1.6.
- 6. The process of claim 5 wherein the second combustible gas consists essentially of propylene.
- 7. The process of claim 1 wherein the mixture contains from about 35 to 80 percent by volume of the oxidant, from about 2 to 50 percent by volume of acetylene, and from about 2 to 60 percent by volume of the second combustible gas.
- 8. The process of claim 7 wherein the mixture contains from about 45 to about 75 percent by volume oxygen, from about 2 to about 45 percent by volume acetylene and from about 5 to about 45 percent by volume of the second combustible gas.
- 9. The process of claim 8 wherein the mixture contains from about 50 to about 70 percent by volume oxygen, from about 3 to about 40 percent by volume acetylene and from about 8 to about 38 percent by volume of the second combustible gas.
- 10. The process of claim 9 wherein said second combustible gas consists essentially of propylene.
- 11. The process of claim 1, 2, 3 or 4 wherein said mixture contains a diluting gas.
- 12. The process of claim 11 wherein the diluting gas is selected from the group consisting of argon, neon, krypton, hydrogen, ammonia, xenon, helium and nitrogen.
- 13. The process of claim 12 wherein the diluting gas is nitrogen.
- 14. In the process of flame plating with a detonation gun which comprises the step of introducing desired fuel and oxidant gases into the gun to form a detonatable mixture, introducing a powdered coating material into said detonatable mixture within the gun, and detonating the fuel-oxidant mixture to impinge the coating material onto an article to be coated, the improvement which comprises using a detonatable fuel-oxidant mixture of (a) an oxidant and (b) a fuel mixture of at least two combustible gases selected from the group of saturated and unsaturated hydrocarbons and wherein the combustion temperature of the fuel mixture is lower than the combustion temperature of one of the combustible gases.
- 15. The process of claim 14 wherein said oxidant is selected from the group consisting of oxygen, nitrous oxide and mixtures thereof and wherein said fuel mixture comprises a mixture of acetylene and a second combustible gas selected from the group consisting of propylene, methane, ethylene, methyl acetylene, propane, pentane, a butadiene, a butylene, a butane, ethylene oxide, ethane, cyclopropane, propadiene, cyclobutane and mixtures thereof.
- 16. The process of claim 15 wherein said mixture contains an inert diluting gas.
- 17. The process of claim 14 wherein said mixture has an atomic ratio of oxygen to carbon of from about 0.9 to about 2.0.
- 18. The process of claim 17 wherein said second combustible gas is selected from the group consisting of propylene, propane and butylene and the atomic ratio of oxygen to carbon is from about 0.95 to about 1.6.
- 19. The process of claim 18 wherein the second combustible gas consists essentially of propylene.
- 20. The process of claim 15 wherein the mixture contains from about 45 to about 70 percent by volume of the oxidant, from about 7 to about 45 percent by volume of acetylene, and from about 10 to about 45 percent by volume of the second combustible gas.
- 21. The process of claim 19 wherein the mixture contains from about 50 to about 65 percent by volume oxygen, from about 12 to about 26 percent by volume acetylene and from about 18 to about 30 percent by volume of propylene.
- 22. In the process for operating a detonation gun having a mixing and ignition chamber and a barrel portion which comprises introducing desired fuel and oxidant gases into said gun through said mixing and ignition chamber, introducing a comminuted coating material into said barrel portion, and detonating the mixture within said gun to impinge the coating material onto an article to be coated, the improvement which comprises using a detonatable fuel-oxidant mixture of (a) an oxidant and (b) a fuel mixture of at least two combustible gases selected from the group of saturated and unsaturated hydrocarbon gases and wherein the combustion temperature of the fuel mixture is lower than the combustion temperature of one of the combustible gases.
- 23. The process of claim 21 wherein said oxidant is selected from the group consisting of oxygen, nitrous oxide and mixtures thereof, and wherein said fuel mixture comprises a mixture of acetylene and a second combustible gas selected from the group consisting of propylene, methane, ethylene, methyl acetylene, propane, pentane, a butadiene, a butylene, a butane, ethylene oxide, ethane, cyclopropane, propadiene, cyclobutane and mixtures thereof.
- 24. The process of claim 23 wherein said mixture contains an inert diluting gas.
- 25. The process of claim 23 wherein said mixture has an atomic ratio of oxygen to carbon from about 0.9 to about 2.0.
- 26. The process of claim 25 wherein said second combustible gas is selected from the group consisting of propane, propylene and butylene and the atomic ratio of oxygen to carbon is from about 0.95 to about 1.6.
- 27. The process of claim 26 wherein the second combustible gas consists essentially of propylene.
- 28. The process of claim 27 wherein the mixture contains from about 45 to about 70 percent by volume of the oxidant, from about 7 to about 45 percent by volume of acetylene, and from about 10 to about 45 percent by volume of the second combustible gas.
- 29. The process of claim 27 wherein the mixture contains from about 50 to about 65 percent by volume oxygen, from about 12 to about 26 percent by volume acetylene and from about 18 to about 30 percent by volume of propylene.
FIELD OF THE INVENTION
This application is a Continuation-in-Part of application Ser. No. 110,841, filed Oct. 21, 1987 now abandoned.
The invention relates to a novel fuel-oxidant mixture for use with an apparatus for flame plating using detonation means and the coated layer produced therefrom. More particularly, the invention relates to a fuel oxidant mixture containing at least two combustible gases such as acetylene and propylene.
Flame plating by means of detonation using a detonating gun (D-Gun) have been used in industry to produce coatings of various compositions for over a quarter of a century. Basically, the detonation gun consists of a fluid-cooled barrel having a small inner diameter of about one inch. Generally a mixture of oxygen and acetylene is fed into the gun along with a comminuted coating material. The oxygen-acetylene fuel gas mixture is ignited to produce a detonation wave which travels down the barrel of the gun where it heats the coating material and propels the coating material out of the gun onto an article to be coated. U.S. Pat. No. 2,714,563 discloses a method and apparatus which utilizes detonation waves for flame coating. The disclosure of this U.S. Pat. No. 2,714,563 is incorporated herein by reference as if the disclosure was recited in full text in this specification.
In general, when the fuel gas mixture detonation gun is ignited, detonation waves are produced that accelerate the comminuted coating material to about 2400 ft/sec while heating it to a temperature about its melting point. After the coating material exits the barrel of the detonation gun a pulse of nitrogen purges the barrel This cycle is generally repeated about four to eight times a second. Control of the detonation coating is obtained principally by varying the detonation mixture of oxygen to acetylene.
In some applications, such as producing tungsten carbide cobalt-based coatings, it was found that improved coatings could be obtained by diluting the oxygen-acetylene fuel mixture with an inert gas such as nitrogen or argon. The gaseous diluent has been found to reduce or tend to reduce the flame temperature since it does not participate in the detonation reaction. U.S. Pat. No. 2,972,550 discloses the process of diluting the oxygen acetylene fuel mixture to enable the detonation plating process to be used with an increased number of coating compositions and also for new and more widely useful applications based on the coating obtainable. The disclosure of this U.S. Pat. No. 2,972,550 is incorporated herein by reference as if the disclosure was recited in full text in this specification.
Generally, acetylene has been used as the combustible fuel gas because it produces both temperatures and pressures greater than those obtainable from any other saturated or unsaturated hydrocarbon gas. However, for some coating applications,, the temperature of combustion of an oxygen-acetylene mixture of about 1:1 atomic ratio of oxygen to carbon yields combustion products much hotter than desired. As stated above, the general procedure for compensating for the high temperature of combustion of the oxygen-acetylene fuel gas is to dilute the fuel gas mixture with an inert gas such as nitrogen or argon. Although this dilution resulted in lowering the combustible temperature, it also results in a concomitant decrease in the peak pressure of the combustion reaction. This decrease in peak pressure results in a decrease in the velocity of the coating material propelled from the barrel onto a substrate. It has been found that with an increase of a diluting inert gas to the oxygen-acetylene fuel mixture, the peak pressure of the combustion reaction decreases faster than does the combustion temperature.
It is an object of the present invention to provide a novel gaseous fuel oxidant mixture for use in a detonation gun that can provide for lower fuel combustion temperatures than that obtainable from conventional oxygen acetylene fuel gases while providing for relatively high peak pressures in the combustion reaction.
Another object of the present invention is to provide a novel gaseous fuel-oxidant mixture for use in a detonation gun that can provide for the same fuel combustion temperatures than that obtainable from conventional oxygen acetylene fuel gases diluted with an inert gas while not sacrificing peak pressure in the combustion reaction.
Another object of the present invention is to provide novel coatings for substrates using the novel gaseous fuel-oxidant mixture of this invention.
The invention relates to a gaseous fuel oxidant mixture for use in a detonation gun, comprising:
The invention also relates to an improvement in a process of flame plating with a detonation gun which comprises the step of introducing desired fuel and oxidant gases into the detonation gun to form a detonatable mixture, introducing a comminuted coating material into said detonatable mixture within the gun, and detonating the fuel-oxidant mixture to impinge the coating material onto an article to be coated and in which the improvement comprises using a detonatable fuel oxidant mixture of an oxidant and a fuel mixture of at least two combustible gases selected from the group of saturated and unsaturated hydrocarbons. The detonation gun could consist of a mixing chamber and a barrel portion so that the detonatable fuel-oxidant mixture could be introduced into the mixing and ignition chamber while a comminuted coating material is introduced into the barrel. The ignition of the fuel oxidant mixture would then produce detonation waves which travel down the barrel of the gun where it heats the comminuted coating material and propels the coating material onto a substrate.
The invention also relates to the coated product obtained using the novel process of this invention.
The oxidant for use in this invention could be selected from the group consisting of oxygen, nitrous oxide and mixtures thereof and the like.
The combustible fuel mixture of at least two gases for use in this invention can be selected from the group consisting of acetylene (C.sub.2 H.sub.2), propylene (C.sub.3 H.sub.6), methane (CH.sub.4), ethylene (C.sub.2 H.sub.4), methyl acetylene (C.sub.3 H.sub.4), propane (C.sub.3 H.sub.8), ethane C.sub.2 H.sub.6), butadienes C.sub.4 H.sub.6), butylenes C.sub.4 H.sub.8), butanes (C.sub.4 H.sub.10), cyclopropane (C.sub.3 H.sub.6), propadiene (C.sub.3 H.sub.3), cyclobutane (C.sub.4 H.sub.8) and ethylene oxide (C.sub.2 H.sub.4 O). The preferred fuel mixture would comprise acetylene gas along with at least one other combustible gas such as propylene.
US Referenced Citations (25)
Non-Patent Literature Citations (2)
| Entry |
| Deposition of Coatings by Detonation Methods, A. I. Zverev et al. Leningrad, Soodestroyeniye Publishers, 1979 pp. 31-32 and pp. 165-166. |
| Coatings Based on Refractory Compounds Applied by Detonation V. I. Shesternenkov and E. A. Astakhov, Leningrad, Nauka Publishers, 1969, pp. 256-257. |
Continuation in Parts (1)
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Number |
Date |
Country |
| Parent |
110841 |
Oct 1987 |
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Patent Grant
4902539
