US 3901441 A
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United States Patent [1 1 Kasagi [451 Aug. 26, 1975 MULTIPURPOSE ELECTRICALLY MELTING WIRE METALIZING MACHINE PROVIDED WITH A MULTIPLE INJECTION PORT  lnventor: Ryoichi Kasagi, No. 5-6,
Minamitsukaguchi-cho l-chome, Amagasaki-shi, Hyogo, Japan  Filed: Sept. 6, 1974  Appl. No.: 503,571
 Foreign Application Priority Data Septv 6, 1973 Japan 48-100463  US. Cl 239/81; 239/84  Int. Cl. B05B 1/24  Field of Search 239/79, 80, 81, 83, 84
 References Cited UNITED STATES PATENTS 1,940,814 12/1933 Sacger, Jr. 239/81 X 2,749,176 6/1956 Steyer 239/84 Primary Examiner-Lloyd L. King Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn and Macpeak [5 7 ABSTRACT A multipurpose metalizing machine is disclosed, which is provided with a plurality of pressurized fluid injection ports. The machine comprises a spraying cylinder replaceably inserted into a dished holding member and adapted to be operable according to various forms of use, using ac or dc power source. Pressurized fluid injected through the plurality of injection ports allows the spraying wires to be melted by a low voltage, low current electric arc and the melted metal sprayed onto a substrate by low pressure air at relatively low velocity.
4 Claims, 10 Drawing Figures PATENTEDAUBZBISYS SHEET 2 [IF 2 NMK PRIOR ART MULTIPURPOSE ELECTRICALLY NIELTING WIRE METALIZING MACHINE PROVIDED WITH A MULTIPLE INJECTION PORT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a multipurpose electrically melting wire metalizing machine provided with multiple injection ports, and more particularly to improvements in its function.
2. Description of the Prior Art Conventional electrically melting wire metalizing machines as shown in FIGS. 8A and B disclosed prior to the aforementioned invention, are known wherein metal wire is melted by an electric arc in the presence of a blast of air at high pressure and high speed. The prior art devices require a large amount of electric power to generate excessive high temperature heat and cause the sprayed metal particles to produce violent oxidation and vaporization, resulting in a considerable reduction in production. Particularly, aluminum, titanium, molybdenum, tungsten, etc. are subjected to flash burning, and zinc in particular is exceedingly vaporized to produce a smarting and exciting impetus and to give out a bad smell, both of which metals are lost half in amount. Further, the sprayed film as an aggregate of sprayed particles involves in practical use various drawbacks, one of which is the disintegration due to the extreme cumulative shrinkage.
This is caused by a metalizing machine in the nature in which melting of metal wire by the electric arc in the presence of air at high pressure generates specific high temperature heat of a phenomenon of plasma to thereby excessively melt the metal and particularly greatly influence on a blast of air surrounding the arc, and to further absorb violent ultraviolet rays and heat thereat, oxygen being ozonized with high density, nitrogen being activated greatly, whereby all these combined action unavoidably result in a significant disadvantageous factor in the quality and economy of the sprayed film.
SUMMARY OF THE INVENTION This invention provides a metalizing machine in the nature in which conversely to the example as described above, spraying wires are melted by an electric are heat of low voltage and low current in the presence of an air current at low pressure and low speed under low vacuum or in the range of about atmospheric pressure in order to introduce protective gases, the coarse particles melted are then introduced into the high pressure and high speed air current at normal temperature, and are sprayed through two stage processes, one being the pulverization into the form of a dendritic structure representative of most favorable entangling combination, the other being the rapid cooling.
In the arrangement of the metalizing machine as hereinbefore mentioned, in the presence of air at low pressure the voltage required to form an electric arc is low, and the arc in the low speed air current remains still and concentrates in a part to be melted, and the amount of heat absorbing dilute air surrounding the arc is extremely small. In that reason, the melting heat efliciency is highest to thereby possess the characteristics capable of melting a number of spraying wires to the optimum temperature; reduction in quantity or change in quality caused by burning, oxidation, nitrization, and vaporization is not produced by the aid of the protective gases; and the spraying air current at normal temperature rapidly cools the dendritic particles with their surface area greatly enlarged satisfactorily prior to adhering to provide a better film at a low temperature, which avoid to produce disintegration accompanied by a fatal shrinkage.
It is an object of this invention to provide a metalizing machine which can improve the spraying ability and spraying function of the metalizing machine according to Japanese Patent No. 673,182 featurized as previously described and which can put to extensive use in the industrial field.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal section principally showing a spraying cylinder of a prior art electrically melting wire metalizing machine;
FIG. 2 is a longitudinal section of a basic electrically melting wire metalizing machine principally showing a spraying cylinder constructed in accordance with the present invention;
FIG. 3 is a front view of the metalizing machine shown in FIG. 2;
FIGS. 4A and 4B are views showing the air-current characteristics of back and forth portions of an electric arc;
FIG. 5 is a longitudinal section showing a transverse spraying cylinder and a frontwardly directed spraying cylinder in the state slid into the long succession cylinder according to the present invention;
FIG. 6 is a view of assistance in explaining the injection tube shown in FIG. 5;
FIG. 7 is a view of assistance in explaining the construction of the third injection port; and
FIGS. 8A and 8B are views of assistance in explaining the principal part of the spraying according to a conventional electrically melting wire metalizing machine used prior to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT One preferred embodiment of the invention will now be described with reference to the accompanying drawings. FIG. 1 is a longitudinal section principally showing a spraying cylinder according to the prior art, spe-' cifically Japanese Patent No. 673,182. FIG. 2 is a longitudinal section principally showing a spraying cylinder of a metalizing machine according to the present invention. Referring first to FIG. 2, a spraying cylinder 1 is detachably and rotatably secured to a dished holding member 10 secured to the front portion of a casing 27. Vent holes 6 are formed in the peripheral wall of said dished holding member 10. Cylinder 1 has threads to engage a generally conical wall body 2 which is internally divided into a high pressure area 31 and a low pressure area 19. Cylinder 1 also has an annular injection port body 5 threaded therein, said wall body 2 and said injection port body 5 being adjusted in their position by screwing and unscrewing.
A clearance formed between the outer extreme end 2A of the wall body 2 and the inner periphery 5A of the annular injection port body 5 defines an annular first injection port 18 for compressed air is introduced via blast pipe 4. Within the casing 27 are mounted serrated wire feeding rolls l2, 12 adjacent to secured conduits 7, 7. Conduits 7, 7 pass through conductive terminals 9,9 connected to power supply not shown, and are detachably disposed by means of bolts 11. 11. The extreme ends of the conduits 7. 7 are bent toward each other in the center near the extreme end of the wall body 2. Spraying wires 8, 8 are guided by the serrated rolls l2. l2 and the conduits 7. 7 to meet in the form of a V-shape at the center front portion of the wall body 2 so as to give out an electric are for continual melting. The speed controlling injection port 40 is one of significant characteristics of the present invention, and is formed so as to communicate with the outer peripheral wall surface 2A of the wall body 2 and the inner peripheral wall surface 28 via a plurality of fine holes formed in the wall body 2.
In describing the air current speed controlling injection port 40, reference will be made to the metalizing machine in which the spraying wires 8, 8 connected to power source are melted by the electric arc 23 within the low pressure air current area 19 formed on the axis of a blast of air 21 at high pressure and high speed which is emitted from the annular injection port 118 in FIG. 1 of the conventional metalizing machine. In the metalizing machine of the type as described where spraying wires 8, 8' which have a large diameter are used for the purpose of increasing the amount of spray or are bent or contaminated, feeding of the wires or energization is impeded and thereby produces irregularities in the are 23 causing the wires to come into contact from each other which results in a violent arc. For this reason, the low pressure air current abnormally inflates so as to reduce, stop or reversely act on the air current speed at the rear of the arc portion, and, accordingly, a part of molten coarse particles does not reach a focus point of a blast of air frontwardly positioned.
In order to overcome this phenomenon, there is proposed the use of dc power source in place of ac power source, or the emission of noninflammable gases such as carbon dioxide gas or compressed air out of a gas current guiding port 24 so as to increase the air current speed. The feed of air to increase speed requires an additional air supply hose, resulting in an increase in weight, and a complexity in opening and closing a controlling cock 32.
To simplify the above structure, the machine of the present invention provides the air current speed controlling injection port 40 communicating with a plurality of fine holes, of about 0.5 mm in diameter, formed through the wall of the wall body 2 obliquely formed frontwardly of the wall surface 2A, as shown in FIG. 2. The third injection port 40 being preferably made within the trumpet-like wall body 2 so as to align with one point of the axis to thereby emit a part of a blast of air from the high pressure air current area 31 into the third injection port 40 so that the amount and the speed of air directed into the wall body 2 and frontwardly of the low pressure air current area 19 may be increased. To accomplish the same operation and effect as those described above, one or more bends 40 may be provided as shown in FIG. 7. However, the FIG. 7 arrangement may be simplified by the provision of the third injection port 40, both being the same in inventive conception.
From the above, it will be understood that during the operation of the metalizing machine as constructed above, the violent injection air current from the first injection port 18 gives a strong action of vacuum upon a conical space and a low pressure air current area 19 is formed internally thereof to absorb even injection air from the third injection port 40 and forms a vacuum of low level.
Atmospheric air to compensate for the vacuum is drawn in through vent holes 6 and gases from the second injection port 24 can also be drawn in. The magnitude of the vacuum is inproportion to the degree of injection energy of a blast of air from the first injection port 18, which is produced at the sacrifice of the energy of a blast of air. The degree of said sacrifice is also in proportion to the vent resistance from the vent holes 6 to the extreme end within the wall body 2 and the injection from the third injection port 40 results in a remarkable reduction in vent resistance. The energy of injected air current from the first injection port 18 does not result in a loss due to the sacrifice but in effect to increase the air current speed within the low pressure air current sphere 19.
FIG. 4 illustrates diagramatically a speed variation within the low pressure air current area 19 in the mo]- ten state by an electric arc where an ac power source is employed. FIG. 4A shows the state of variation in an (E) line-like ordinary state air current speed wherein injection is not effected from the third injection port 40, and in this case, when a normal arc formation is taken place, the forward portion A of an inflated gas 25 in the arc increases in speed while the rear portion B decreases in speed, and both the forward C portion and the rear D portion of an irregular gas 26 in the arc greatly vary in speed, the rear portion D sometimes producing an instantaneous backflow phenomenon.
As such a backflow phenomenon occurs, a part of molten coarse particles is diffused rearward, which should absolutely be avoided.
FIG. 4B shows the state of variation in a (F) line-like ordinary state air current speed wherein injection of compressed air is effected from the third injection port 40, and in this case, the air current speed in the low pressure air current area 19 increases so that the backflow phenomenon can be completely eliminated even in the case of the irregular inflated gas 26 in the arc. Thus, the use of spraying wires having a great diameter in the range of an unlimited extent becomes possible only by metering the air in a fine amount.
Further, if arrangement is made depending upon the kind and use of spraying metal so that suitable protective gases are injected from the second injection port 24 to provide a sprayed film of good quality, thus serving as a means for accomplishing a multiple purpose later described as well as the provision of great efficiency.
FIG. 5 is a longitudinal section showing a transverse spraying cylinder and a frontwardly directed spraying cylinder placed into the long succession cylinder of the present invention. In this arrangement, the annular clearance in the first injection port 18 is made extremely narrow to remove the function of a blast of air while retaining the function of the low pressure air current area 19 thereby limiting the quantity of air to approximately one-tenth of that used in blasting, and in place thereof, the number of the third injection ports 40 is increased or the diameter of hole is made slightly greater so as to increase the amount of injection maintaining the vent speed as shown in the (F) line of FIG. 4B for the prosecution of spraying. Thus, the injection energy at the first injection port 18 is weak, and the molten metal is concentrated 'at the focus point 20 through pulverization and cooling ability of the molten metal are extremely poor, and the molten metal is further accelerated to form into greater spherical particles and flying about in distance from 1 to 2 meters in the form of a line. When they impinge upon the frontward subject, they are formed into a palm-like flat body, which is an accumulation easily separated from one another. Upon formation of such a state as described above, if spraying is carried out followed by adjustment so made that the aforementioned molten coarse particles are rushed into the axis ofa blast of air 21 in the transverse direction injected out of the fourth injection port 50 at the extreme end of the fourth injection port tube 51 located by the first injection port 18 as shown in FIG. 5, the molten coarse particles are rushed into the powerful blast of air 21 in the transverse direction and instantaneously therewith the particles are pulverized, cooled and accelerated to form a transverse spraying cylinder forming a sprayed film at right angles to the spraying cylinder 1.
This machine as described can advantageously be used to build-up hard metal or lubricating metal or alloy on objects such as cylinders and bearings, or potlike objects, and interior surfaces of a deep hole of a large-sized object formed with a small-diameter mouth having a part in the condition similar to the former. Such spraying is carried out by placing the succession cylinder 1 having the length according to the depth of object to be sprayed and the conduit 7 into mutually holding relationship with a permeable insulating support 41, adjusting the cylinder to be suited to the desired length.
In spraying, it is a significant requisite to spray on the object to be sprayed at a right angle or an approximate right angle thereto. In the past, it has been considered extremely difficult to form a small diameter curved interior surface such as an interior surface of cylinder with a thick sprayed film. This is due to the use of the metalizing machine which has its function to spray metal in the molten or semi-molten state as is mentioned in the definition of spraying. The metal particles in the molten or semi-molten state sprayed has its single contraction coefficient peculiar to metal or alloy such as casting, and an individual particle forming a film becomes a cumulative film contracted in proportion to the thickness (number of overlapped particles). Since it radiates melting heat and contracts as it so radiates, it results in the excessive degree of overall contraction, and forms into a small diameter film considerably smaller than the inside diameter of object to be sprayed. In addition, the difficulty of spraying at a right angle results in a poor adhesive force and in a fragility of film thus producing the natural separation. Conversely, the sprayed film sprayed at a normal right angle after metal particles have been called prior to adherence, as is carried out by the metalizing machine of the present invention, naturally possesses the low contraction coefficient, the firm adhesive force, the powerful bonding force of particles from one another, and the extremely high stability.
Further, forwardly directed large quantity spraying may be effected in the same operation as that of the above-described transversely directed spraying by pro viding the spraying cylinder 1 with a plurality of injection port tubes 61 and protective frames 62 for protecting thereof as indicated by the dotted lines in FIG. 5 in place of the fourth injection port tube 50 which is mounted in the outer periphery of the first injection port 18. A fifth injection port 60 as shown in FIG. 5 is mounted to surround the forward axis of the first injection port 18 in the attempt of integration of the injection port tubes 61.
The metalizing machine described above is suited to spray on the bottom of cylinder and other deep end portions to which the metalizer is usually hard to access. Particularly, in the case of spraying large-sized structures for a corrosion resistant coating as specified, it quite often'suffers from difficulties not capable of spraying some part of structure due to not only the depth but angularity involved in its construction, which reduces the value of the structure, but these problems noted above may be solved by the present spraying cylinder which can suitable adjust the length and the spraying angle. This construction of the lengthy spraying cylinder was realized by the use of large-diameter spraying wires, which increase the rigidity and have less flexibility and bending, thereby stabilizing the feed of wire between the delivery rolls l2 and the electric arc 23. It will be understood that such a construction as just mentioned may of course be applied to a generalpurpose metalizing machine, which is handy and directed at a large amount spray, in the form of the short (without using the succession cylinder 1) spraying cylinder l.
The greatest problem heretofore encountered in the field of machining technology of ordinary spraying can be said to build-up layers by spraying. The reason is such that spraying on the plane causes the film to be peeled off, and spraying on the outer surfaces of a columnar structure causes the film to be cracked. To describe how things stand now, the object of spraying is being barely accomplished by the aid of severe prior and posterior treatment and by the limitation of thickness. This is caused by the cumulative contraction due to the peculiar phenomenon as previously described. However, the metalizing machine of the invention provides better workability because of its small type and light-weight and solves those problems as noted above by a combined ability of both quantity and quality. Thus, the present invention provides a multipurpose electrically melting wire metalizing machine provided with a multiple injection port having the extensive characteristics such as a noticeably wide application because of its capability of machining various materials or parts, which are hard to resist to heat and thermal shock.
Further, the ac power source is economical because the voltage can be readily regulated according to the kind and diameter of various metal and alloys, whereas the disadvantages as described above tend to be involved due to non-continuous melting. It is obvious that since the better condition in ac source is continuous melting in dc power source, the melting ability becomes more effective by increasing it about 3 times.
Conversely, the present invention has been realized as a result of study paying special attention to the ac power source, which has various disadvantages, in the attempt of thoroughly improving the function, and therefore provides a metalizing machine characterized in that the object may be accomplished using either ac or dc as a power source independently of place and time or kind of metals.
What is claimed is:
1. In an apparatus for spraying molten metal onto a substrate of the type wherein two or more metallic wires are conveyed through a casing in contact with electrical conductors, said wires being brought into close proximity after passing through said casing so as to cause an electric arc therebetween to melt the metal wires, said melted metal is conveyed to the substrate by a stream of high pressure fluid, the improvements comprising:
a. a spraying cylinder (1) removably affixed to the end of said casing such that said wires are brought into proximity along the approximate axis of said spraying cylinder, said spraying cylinder having a plurality of radial aperatures therethrough adjacent the end affixed to said casing,
b. a hollow, generally conical wall body (2) attached to the inner surface of said spraying cylinder (1) at one end thereof, said conical wall body (2) having a plurality of aperatures (40) therethrough, the axes of said aperatures forming an acute angle with the central axis of said conical wall body (2),
c. an annular injection port body (5) attached to the interior of the distal end of said spraying cylinder l), the inner diameter of'said injection port body and the outer diameter of said conical wall body defining a first injection port (18) therebetween,
d. first injection means to inject a pressurized fluid through a wall of said spraying cylinder 1) into a high pressure chamber (31) defined by the inner surface of said spraying cylinder 1), said conical wall body and said annular injection port body, and
e. second injection means (24) to inject a pressurized fluid interiorly of said conical wall body.
2. The metal spraying apparatus of claim 1 further comprising:
an injection port tube (51) extending through said annular injection port body (5) and communicating with the high pressure chamber (31), the distal end (50) of said port tube being curved so as to direct the flow of pressurized fluid from the pressurized chamber 31) at an approximate right angle to the central axis of said spraying cylinder (1).
3. The metal spraying apparatus of claim 1 further comprising:
a plurality of injection port tubes (61) extending through said annular injection port body (5) and communicating with high pressure chamber (31), the distal ends of each of said port tubes (61) being bent toward the central axis of said spraying cylinder (1), to direct pressurized fluid at an acute angle to said central axis.
4. The metal spraying apparatus of claim 1 wherein a plurality of spraying cylinders are coaxially mounted on said casing, said conical wall body (2), said annular injection port body (5), and said first and second injection means being located in said spraying cylinder furtherest from said casing.