US 2896571 A
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Description (OCR text may contain errors)
Jilly 28, 1959 GEERTSEN 2,896,571
SPRAY HEAD WITH PROTECTIVE SHIELD Filed Feb. 11, 1955 INVENTOR.
N ELSON GEERTSEN AT TORN EYS United States Patent SPRAY HEAD WITH PROTECTIVE SHIELD Nelson Geertsen, Oak Park, Ill., assignor to American Can Company, New York, N.Y., a corporation of New Jersey Application February 11, 1955, Serial No. 487,578 Claims. (Cl. 118-318) The present invention relates to spraying machines, especially machines for, spraying 'or coating interior surfaces of containers or cans with a liquid coating material and has particular reference to devices for shielding the spraying element to protect it against the accumulation of excess coating materialon its exterior surfaces. This is an improvement on the Can Spraying Machine disclosed in United States Patent 2,103,270 issued on December 28, 1937 to J. H. Murch.
In the high speed production of interiorly coated containers or cans, the coating operation preferably is effected by rotating the cans rapidly on their axes while inserting and withdrawing a spray head which projects a fine spray of the coating material onto the inner surfaces of the spinning cans. The spraying operation creates within the cans a concentrated atmosphere of the coating material which is whirled into a state of turbulence by the spinning action of the cans, with the result that the spray head becomes covered with the'coating material and also small pellets of the coating material are formed and are projected against the interior surface of the cans. As the spraying continues the coating material collected on the head builds up to proportions which cause it to drop off into the cans and thus taken together with the whirling pellets, produce in the cans, gobs of coating material which render the cans useless.
To partially over-.
2,896,571 Patented July 28, 1959 Referring to the drawings:
Figure 1 is a sectional view of a can spraying machine embodying the instant invention, the view being taken through the spraying station of the machine;
Fig. 2 is an enlarged view of the spraying head used in the machine, portions being shown in section and portions being broken away;
Figs. 3 and 4 are views similar to Fig. 2 and illustrating modified forms of the invention;
Figs. 5 is an enlarged sectional view of the portion of the head shown at the bottom of Fig. 2; parts being broken away;
Fig. 6 is a transverse sectional view as taken substantially along the line 66 in Fig. 5; and
Fig. 7 is a view similar to Fig. 6 and showing a modified form of the invention.
As a preferred or exemplary embodiment of the invention the drawings illustrate principal parts of a can spraying machine of the character disclosed in the above mentioned Murch Patent 2,103,270. In such a machine, sheet metal cans A (Fig. 1) having bottoms B secured in place and having open tops, are advanced through the spraying station of the machine, in a substantially horizontal position, by a rotatable turret 21 (Fig. 1). The turret 21 preferably is composed of a pair of spaced parallel discs 22 having peripherally spaced pockets 23 in which the cans are located as shown in the Murch patent above mentioned.
The turret 21 is mounted on a drive shaft journaled in bearings formed in a machine frame 24 as in the Murch patent. The shaft is rotated intermittently to advance the cans into and out of the spraying station come this difficulty frequent shut-down of the spraying machine is required to clean the spray heads.
The instant invention contemplates overcoming these difliculties by the provision of devices which blow out the concentrated mist of coating material created within the cans and thereby prevent the formation of pellets and the accumulation of the coating material on the spray head. i
An object of the instant invention is the provision in a machine for spraying the interior surfaces of cans, of devices which dissipate the concentrated mist of coating material created within the cans during the spraying operation and thereby prevent the formation of pellets of coatlng material and the accumulation of coating ma- 'terial on the spray head so that the interior surfaces of the cans will be properly coated and free of excess coating material which render the cans useless.
Another object is the provision of such devices which permit of continued operation of the spraying machines without shut downs for cleaning of the spraying heads.
Another object is the provision of such devices which insures against the throwing from the spinning cans, of pellets of coating material so as to prevent the accumulation of excess coating material on the outer surfaces and to hold the cans at the station for the spraying operation. In the Murch patent two cans A are shown being sprayed interiorly at the same time, one canreceiving a first coat and the second can receiving a second coat to insure full coverage of the surfaces to be coated.
While the cans A are at the spraying station they are rotated by a pair of electromagnetic chucks 26 which are disposed in axial alignment with the turret pockets 23 and which attract and magnetically hold the cans by their bottom ends B. The chucks 26 are rotated in unison and in the proper direction by a pair of meshing spur gears 27. The gears 27 and the chucks 26 are mounted on drive shafts 28 which are journaled in bearings 29 in the machine frame 24 and which are rotated in any suitable manner as shown in the above mentioned Murch patent.
The spraying of the cans A is eifected by tubular spray heads 31 which are mounted for reciprocation toward and away from the turret 21 and are movable into and out of the rotating cans A at the spraying station for the spraying operation as disclosed in the Murch patent above mentioned. The spray heads 31 preferably include a tubular body 32 (see Fig. 5) havingsecuredat its free outer end a conventional spray nozzle 33. The nozzle 33 is in communication with the interior of the 'body 32 and with a pipe 34 which extends through the body. At its outer end, the pipe 34- is connected to a source of supply of the liquid coating material to be sprayed onto the interior surfaces of the cans A. This pipe conducts the coating material to the nozzle.
The end of the tubular body 32 remote .from the nozzle 33 is connected to a source of supply of compressed air manner.
creates the undesirable concentrated mist within the cans duringthe spraying operation.
Provision is made to dissipate the mist within the spinning cans A to prevent the formation of pellets and to prevent accumulation of the. coating, material on the spray heads 31 as mentioned hereinbefore. For th1s purpose the spray head body 32 carries a cylindrical collar 42 which is secured to the body in any suitable The collar preferably is located back from the nozzle end of the body a distance of approximately three inches. The inside of the collar 42 is formed with a wide annular groove or recess 43 which surrounds the spray head body" 32 and. is in communication with the interior of the body by way of a plurality of apertures 44 formed in the body. These apertures permit compressed air from the interior of the body to enter the groove 43 in the collar.
One end of the collar 42, preferably the end facing the nozzle 33, is provided with a fiat face 46 containing a plurality of fine, closely spaced orifices 47 (see Fig. 5) arranged in a circle preferably extending entirely around. the head body 31 (see Fig. 6) and in communication with the groove 43 in the collar. These orifices 47 permit the compressed air in the collar groove 43 to'escape forcibly from the orifices 47 in jets which travel toward the spray nozzle 33 substantially in parallelism with and close to the head body 32 and thereby produce a substantially continuous curtain 48 of compressed air which. completely envelopes the head body forward of the collar, including the nozzle at the end of the body. This curtain 48 of air around the head body shields the body and the nozzle from the concentrated mist of coating material within the can A and thereby prevents the mist from falling or being otherwise deposited on the body and the nozzle.
The curtain 48 of compressed air also impinges against the bottoms B of the spinning cans A and bounces back out of the open ends of the cans to sweep out and completely dissipate the mist of coating material within the can and thereby prevents the formation of pellets which would otherwise form and mar the inside coated surfaces of the cans. This mixture of mist and air as it leaves thecans is received in a conventional exhaust duct 51 (Fig. l) which carries the mixture off to any suitable place of disposal.
For long cans, or for other purposes it may be desired to provide a curtain 48 of air which protects a longer length of the spray head body 32. Fig. 3 illustrates such a device as a modified form of the invention, in which an end face 52 disposed at the end of the collar opposite the face 46 is provided with the orifices 47 as well as the face 46. In this case where opposite faces of the collar 42 are formed with the orifices 47, two curtains 48 traveling in opposite directions along the body 32 are provided to envelope the head body. In this modified form of the invention a curtain 48 of air issues from the open end of the can directly and-thus cooperates with the other curtain 48.
As a second modified form of the invention Fig. 4 shows a double curtain of compressed air traveling in the same direction and enveloping the spray head body 32. In this form: of the invention a direct outside source of supply of compressed air or other fluid medium is used. For this purpose the head body 32 is imperforate and is surrounded by a sleeve 54 having collars 55, 56 formed on opposite ends of the sleeve and surrounding the body 32. The lower collar 56 is connected to a in Fig. 4 these orifices preferably are formed in the end.
recting the curtains of air toward the nozzle. However these orifices may be formed in either end face of the collars 55, 56 to provide any combination of directional flow for the curtains. Collar 55 may have orifices in both end faces for directing the curtains of air in opposite directions and collar 56 have orifices in the lower face to correspond withthe orifices in the lower face of collar 55, or the reverse order may be provided in which orifices are in both faces of collar 56 and only one face of collar 55 as desired. The main feature in this form of the invention is the separate source of compressed air or other fluid medium.
In some cases where the protective curtains of air interfere with the spray 36 issuing from the nozzle 33, the orifices in the region of the spray may be omitted such as shown in a modified form of the invention illustrated in Fig. 7. It has been found that the elimination of these orifices inno way detracts from the effectiveness of the remainder of the orifices in producing an air cur tain which protects the spray head 31 from the accumulation of coating material and also prevents the formation of deleterious pellets as mentioned hereinbefore.
It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the. form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.
1. In a machine for spraying interior surfaces of containers with a liquid coating material, the combination of means for supporting said containers in a substantially horizontal position, spraying means disposed adjacent said support for projecting a spray of atomized coating material onto the interior walls of said containers, said spraying means including an exposed hollow body memfaces of the collars 55, 56 nearest the nozzle 33 for di- 75.
her having a free outer end and a spraying nozzle disposed at said free outer end of said body member, said body'member being connected to a source of compressed. air'for supplying said compressed air to said nozzle, means for inserting said nozzle anda predetermined portion of said body member into said containers in a; substantially horizontal direction for a spraying opera tion, a collar carried by and movable with said body member, said collar being spaced inwardly from said nozzle and disposed at the inner end of said inserted portion and provided with an internal recess, anaperture formed in said body member for supplying compressed air from the interior of said body member to said recess, and means formed in said collar for receiving compressed air from said recess. and for projecting said compressed air as a curtain along and around said'nozzle and substantially the entirerinserted portion of said exposed body member to prevent the deposition and' accumulation thereon of excess coating material existing as a mist inside of said containers and the consequent dripping of said accumulated coating material onto the interior Walls of said containers.
2. The mechanism of claim 1. wherein said means formed in said collar comprises a plurality of orifices arranged around the end face of said collar nearest said nozzle.
3. In a spray head for a machine. spraying interior surfaces of containers with a liquid coating material, the' from the mist surrounding said head as a result of the spraying operation.
4. In a spray head for a machine spraying interior surfaces of containers with a liquid coating material, the combination of a body member, a nozzle at one end of said body member for projecting a spray of said coating material onto said container surfaces, and a plurality of collars surrounding said body member and having annular recesses for receiving a fluid medium under pressure, each of said collars having at least one face thereof provided with a plurality of orifices arranged around said body member for projecting along said body member a curtain of a fluid medium to protect said head against the accumulation of excess coating material thereon from the mist surrounding said head as a result of the spraying operation.
5. In a spray head for a machine spraying interior surfaces of containers with a liquid coating material, the
combination of a body member, a nozzle at one end of said body member for projecting a spray of said coating material onto said container surfaces, and a collar surrounding said body member and having an annular recess for receiving a fluid medium under pressure, said collar having at least one end face provided with orifices ar ranged around said body member for projecting along said body member a curtain of a fluid medium to protect said head against accumulation thereon of excess coating material surrounding said head as a result of the spraying operation, said orifices being disposed in spaced relation entirely around said body member except for the region aligned with the spray issuing from said nozzle to protect said spray against distortion by said curtain of fluid medium.
References Cited in the file of this patent UNITED STATES PATENTS 2,028,355 Russi Ian. 21, 1936 2,103,270 Murch Dec. 28, 1937 2,438,471 Ball Mar. 23, 1946 2,708,597 Wiitala et a1. May 17, 1955 2,712,961 Richardson July 12, 1955