Combustion – Timer – programmer – retarder or condition responsive control – Control of purger – of scavenger or of combustion start-up...
Patent
1985-04-24
1987-12-08
Green, Randall L.
Combustion
Timer, programmer, retarder or condition responsive control
Control of purger, of scavenger or of combustion start-up...
431160, 431126, 431256, F23N 500, F23C 506
Patent
active
047116277
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a device for the thermal spray application of fusible materials, consisting of a cooled pinch nozzle having a space expanded on the feeding side for receiving therein devices for the controlled feeding of operating components such as operating gases and fusible material.
Devices of the above type for the thermal spray application of powders are known from German Pat. DAS No. 1 089 614. The additional state of the art is represented by the European patent application No. 812 01061.9 and trade publication "Metall", No. 3/83, page 238, FIG. 1b. With the last-mentioned device, nitrogen is used as the conveying gas, whereby the flame (the fuel gas is a mixture of methylacetylene propadiene and oxygen) is formed in the water-cooled pinch nozzle. The process according to European application No. 812 01061.9 requires a costly dosing system with electronic control and timing devices, i.e., said associated equipment is very expensive and its purchase and use is worth the expenditure only in certain cases of application, although with such a system (the operating materials or components are combined with each other according to the equal-pressure principle), it is possible to achieve spraying qualities that can readily bear comparison with those obtained in plasma and flame shock spraying operations, i.e., the quality is very high. However, since said systems cannot be operated with the use of pure acetylene and in view of their high cost, their application is obviously not justifiable for, in a manner of speaking, normal cases of spray application, i.e., in such normal cases, it was not possible until now to exploit with the simpler means the advantages offered by such a process and such a pinch nozzle, namely the prevention or reduction of spraying losses, superior fusion of the particles and higher particle acceleration.
The device according to the afore-mentioned German Pat. DAS No. 1 089 614 is not equipped with a combustion chamber, but designed in a way such that the orifice of the carrier gas/powder outlet duct is arranged directly within the zone feeding into the pinch duct of the pinch nozzle, whereby the expanded space around the nozzle serves only for feeding the oxygen, the latter being admixed with the stream of carrier gas and powder by way of an annular clearance. Aside from the hazard of backfire in the duct feeding the carrier gas and powder, the nozzle is not designed for adjustment, which means no adaption to different types of powder is possible. Furthermore, the entire device has to be ignited from the front, which poses some hazard also.
Therefore, the present invention is based on the problem of providing a device operating with comparably low spraying losses. Said device, which operates based on the so-called differential pressure principle, does not require more or only insignificantly more with respect to equipment expenditure than what was needed until now for flame spraying, on the one hand. On the other hand, by virtue of the adaptability of its combustion chamber, it permits the use of all combustible gases, in particular also the use of acetylene and different types of spray powders. Furthermore, also the ignition or start-up operations can be safely controlled.
Accordingly to the invention, said problem is solved with a device of the type specified above by the following features: The expanded space is designed as the combustion chamber with a flow-accelerating contour of transition into which the pinch nozzle is discharging, and a burner nozzle or a nozzle holder with a nozzle is arranged in said combustion chamber, said nozzle being axially adjustable with respect to the orifice of the pinch nozzle and charged with differential pressure. Furthermore, an ignition electrode is arranged in the wall of the combustion chamber, said electrode being adjustable with respect to the nozzle and provided with a switching element for switching on the electrode after the flushing of the pinch nozzle and before the combustion gas is fed. Advantageous additional features of
REFERENCES:
patent: 2950867 (1960-08-01), Hawley et al.
patent: 3109481 (1963-11-01), Yahnke
patent: 3112072 (1963-11-01), Malone
patent: 3209810 (1965-10-01), Schuvart
patent: 3311789 (1967-03-01), Remy
patent: 3563683 (1971-02-01), Hess
patent: 4437415 (1984-03-01), Spielman
Metall, No. 3/83, Mar. 1983, pp. 237-239.
Oeschsle Manfred
Simm Wolfgang
Streb Karl-Peter
Szieslo Uwe
Castolin S.A.
Green Randall L.
Kelman Kurt
LandOfFree
Device for the thermal spray application of fusible materials does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for the thermal spray application of fusible materials, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for the thermal spray application of fusible materials will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-21210