US1796820A - Apparatus for treating objects - Google Patents

Description

March 17, 1931. A. H. ADAMS APPARATUS FOR TREATING OBJECTS Original Filed Nov.

Jizvan or 5277210" Hflaams Patented Mar. 17, 1931 UNITED STATES. PATENT OFFICE ARTHUR HERMAN ADAMS, OF YONKERS, NEW YORK, ASSIGNOE T WESTERN ELEC- TRIC' COMPANY, INCORPORATED, OF NEW YORK, Y., A. CORPORATION OF NEW YORK ATPARATUS FOR TREATING OBJECTS Original application filed November 19, 1927,'Serial No. 234,361. Divided and this application filed November 24, 1928.

This invention relates to apparatus for treating objects, and more particularly to apparatus for applying coating material to objects.

The object of this invention is to provide an improved apparatus for treating objects in an expeditious and economical manner to provide a smooth, uniform coating, and is a division of my co-pending application,

Serial No. 234,361, filed November 19, 1927.

In accordance with the general features of this invention there is provided in one embodiment thereof a freely rotatable basket containing loosely arranged objects to be coated, which is designed to be immersed in a bath of molten tin, zinc, alloy, wax, pitch, or other coating material. The bath, which may be tin, is contained in a rotatable receptacle provided with an enlarged portion.

When the receptacle is rotated, motion is also imparted to the perforated basket through the bath of molten tin, and when a certain speed is attained the major part of the tin is gradually thrown outwardly, due

to the action of centrifugal force as speed is acquired and collects in the enlarged portion of the receptacle, leaving the perforated basket entirely free of the bath of tin.

During this stage of the operation the bath of molten tin gradually recedes from the objects in the basket, removing as it recedes all excess tin by the combined effect of the surface tension of the bath of tin and of centrifugal and gravitational forces, thereby resulting in a smooth and uniform coating.

The effect is the same as though a basket of objects was withdrawn from a bath of tin in a much greater gravitational field than the earth affords.

Other objects and advantages of this invention will more fully annear from the following detail description taken in connection with the accompanying drawing, in which Fig. 1 is a fragmentary plan view of an apparatus embodying the features of this invention;

Fig. 2 is a vertical section, partly in elevation, taken on the line 2'2 of Fig. 1, and 50 Fig. 3 is a fragmentary detail section Serial No. 321,622.

through the vertical axis of the basket which holds the objects.

Referring now to the drawing in detail wherein like reference numerals indicate similar parts, and particularlv to 'Fig. 2, a circular base 10 rotatably supports by means of suitable anti-friction bearings a circular receptacle 11. Attached to a lower reduced bearing portion of the receptacle 11 is a worm gear 12 which meshes with a worm 13 which may be driven from a suitable source of power (not shown). The receptacle 11 is provided with an enlarged portion 14 at its upper end, the purpose of which will become apparent as this description progresses, the portion let having an axial opening 15 at its top surface.

Coaxially arranged with and rigidly supported above the receptacle 1 1 is a non-rotatable shaft 18 which is adapted to be reciprocated in a vertical direction by any suitable means (not shown). Rotatably mounted upon the lower end of the shaft 18 by suitable anti-friction bearings is a sleeve 19, a head 20 of the shaft holding the sleeve thereon. The sleeve 19 is provided in the present instance with three outwardly and downwardly extending arms or spiders 21. Suspended from the free ends of the spiders 21 is a circular basket 23 formed of sheet metal having its vertical and lower walls perforated, the whole being strengthened by aplurality of metal bands '24, the upper ends of which extend above the top edge of the basket and above a normal immersion level 25 of the molten tin or other coating are attached to the upper ends of the bands 24 by suitable readily releasable means.

The sleeve 19 is of such a length that taken with the three spiders 21, the basket 23 is maintained suflicicntlyrigid upon the shaft 18 in the o eration of the apparatus that no apprecia le lateral movement of the basketwithin the receptacle 11 occurs. The receptacle 11 is provided with a plurality of circularly and uniformly arranged ribs 26 extending from its inner peripheral wall toward the axis thereof and spaced from the peripheral surface of the basket 23 sufficiently to not interfere with its free rotation. In" addition to one purpose of the ribs 26 which will be described hereinafter in the description ofoperation of: the apparatus, they also serve-as a means to steady the v basket 23 during its rotation and facilitate the guiding thereof through the opening 15 of the receptable and into the ring guard 33 in the basket 23-by inserting the lower end thereof in a sleeve 29 (Fig. 3) fixed to the bottom wall of the basket within the axial opening thereof. The upper end of the tube 27 is flared and lies flush with 'the upper edge of the basket 23. The purpose of the tube 27 in the operation of the apparatus serves as a depository for dross or other foreign matter contained in the bath, which in the centrifuging action is attracted to the axis of the rotating parts by the vortex created and flows into the flared mouth of the tube and is retained at the ottom thereof by, the sieve 28, any molten metal passing therethrough.-

Surrounding the lower reduced portion of the receptacle 11 is an oven 30 provided with a plurality of nozzles 31 for projecting.

against the sides of the receptacle gas flames to maintain the tin and the objects to be coated at a sufliciently high temperatureto facilitate the flow of the metal around the objects to thoroughly envelop them and in the centrifuging action the removal of all excess metal therefrom. Attached to the walls of the oven 30 and surrounding the enlarged portion 14 of the rotatable receptacle 11 is a housing or guard 32 provided at its upper end with a collar portion 33, the diameter of which is suficient-ly large to receive the basket 23 when it is raised from the receptacle 11 during the centrifuging operation to be described shortly hereinafter. The portion 33 serves to prevent the scattering of molten metal particles into the space above the top of the guard 32 with the likelihood of injury to an operator as the rotating basket is raised from the'receptacle l1. Substantially one-half of the portion 33 may be swung open about a hinge 34 to permit the basket 23 to be moved from the apparatus to another position. To permit this the reciprocable shaft 18 with the attached basket 23 together with the means for reciprocating it may be swung to one side upon being drawn upwardly to the dotted line position, the basket 'detached therefrom, another basket attached thereto and then swung back into axial alignment with the receptacle 11.

Upon the rotating basket 23 reaching the dotted line position thereof a circular brake surface 37 formed upon the upper end of the sleeve 19 engages a suitably supported stationary friction member 38. The member 38 is ring shaped but cut open on one side to permit the shaft 18 with the basket 23 to be swung to one side as described hereinbefore. Thus the basket 23 is quickly brought to a stop upon reaching its upper position.

In practicing a method of metal coating small objects with the 'hereinbefore described apparatus the bath of tin contained in the receptacle 11 is brought to a suitable temperature in the manner and for the purposehereinbefore described. The bath of tin is then skimmed of any surface im urities and the basket 23 with the objects t erein is lowered into the bath and when the basket has been completely submerged the receptacle 11 is caused to rotate. The speed of rotation of the receptacle 11 may be increased very rapidly by the normal acceleration of a motoror belt driving it through the worm 13. The bath of tin will accel erate moregradually, due to its friction on the walls of the receptacle 11. The ribs 26 of the receptacle 11 it will be apparent serve to facilitate the rotation of the bath of tin around the basket 23 and thus the latter is caused to rotate with it. In fact, the bat-h cannot rotate much more rapidly than the basketydue to the surface friction created between the mass of tin, the basket and the mass of objects therein. As the velocity of the bath and basket increases the centre of the bath collects the lighter or surface slag and impurities and the crater of the surface is finally lowered sufiiciently to be intersected by the flaring top edge of the tube 27, thus segregatin these impurities so theycannotv descend with the clean metal and be deposited on the objects in the basket, Just after this occurs, and not before, the level of the tin reaches the height of the objects in the basket 23, it is well to further cleanse the surface of the bath by sprinkling.

it with a flux, such as rosin, tallow, any very high flash paint oil, or with dry zinc chloride or ammonium chloride. The specified fluxes are particularly adapted for use with baths of tin and when other baths are employed suitable fluxes therefor should be sev lected. Th impurities will be intercepted by the tube 7 and confined within thatvtube until the central level of the bathis lowered to a pointjust below the screen 28, where all but the finest of the slag and impurities will be deposited. The tube 27 as hereinbefore described is removable so that theslag and impurities may be readily removed therefrom and the screen 28 cleaned. The

or corner 40 of the receptacle 11, into the I upper and outer enlarged portion 14 thereof. Obviously as this process continues the bath fiowsvery gradually away from the basket and the therein contained objects, its surface moving through them both downwardly and outwardly, forming in the lower part. of the receptacle llsuccessively paraboloids of revolution. It will be noted that each drop of tin on any object near the surface of the bath is pulled in a direction normal to that surface by the resultant of centrifugal and gravitational forces. It will be noted that the surface tension of this receding surface is also in this same direction. The method and apparatus of the present invention is particularly useful in that the last drop on any outward edge or corner of an object, which is very hard to throw off and which is likely either to remain or make a lump when cold or dry, or to fly off and spatter up others of the massof objects is removed due to the additive stripping effect of gravity, centrifugal force and surface tension. Also since it is not necessary to remove the objects from the eflects of the hot bath, additional heat is not required to keep the metal or material on their surface uniformly hot and free flowing and the formation of oxides and slags is thereby prevented.

It will be clear that, as soon as the bath has attained the speed of the receptacle 11, which can be determined in a number of ways, as by thepower consumption going down, cessation of power loss in fluid friction, or by a simple observation through the top opening by a mirror, or more practically by noting once and for all the time it takes, there isno further advantage in continuing to revolve the basket 23, but rather a danger of cooling the parts and of sticking them together. The basket then should be raised to the position shown in dotted lines insideof guard ring 33, and its rotation should be stopped as quickly as possible, which may be accomplished through the use of the brake surface 37 engaging the stationary friction member 38.

The power should be cut off from worm 13 and the'receptacle 11 allowed to come to rest. The bath therein will also come to rest and become level, which is facilitated, it will be apparent, by the ribs 26 of the receptacle 11. It may require replenishing at this time.

The basket is removed from the spiders 21, dumped quickly so the objects will not i stick together. The strainer 28 is cleaned, the basket is refilled, or another one already filled with objects ready for coating may be used, and replaced on the spider andthen subjected to the molten bath which has been prepared in the manner previously described.

Although this invention has been dis closed and described in connection with the coating of small objects with tin, it will be understood that the invention is capable of other applications and is only to be limited by the scope of the appended claims,

WVhat is claimed is:

1. In an apparatus for treating objects, a receptacle containing treating material, a receptacle for immersing objects to be treated in the treating material, and means for effecting relative movement between the treating material and the receptacle containing the objects immersed therein resulting in the formation of a hollow in the treating material free from the objects and the removal of the excess treating material from the objects.

2. In an apparatus for treating objects, a rotatable receptacle containing treating material, means for immersing the objects to be treated in the treating material, and

means for rotating the receptacle to cause a centrifuging of the treating material free. from the objects.

3. In an apparatus for applying coating material to objects, a rotatable receptacle containing coating material, means for immersing the objects to be treated in the material, means for rotating the receptacle to cause a centrifuging of the residual material free from the objects, and means for withdrawing the coated objects from their normal immersion tacle.

4. In an ap aratus for appl ing coating material to o jects, a rotatable receptacle containing coating material, a perforated basket for holding the objects to be coated,

a reciprocal member from which the basketis suspended for causing an immersion of the basket in the coating material, the re level in the recep 'ceptacle, the basket and the member being .in coaxial alignment, and meansfor rotating the receptacle to cause a centrifuging of the residual material freefrom the basket and the objects therein.

5. In an ap aratus for applying coating material to o jects, a rotatable receptacle containing coating material and having .an enlarged diameter at its forated" basket for holding the objects to be coated, a reciprocal member u on which the. basket is rotatably suspende for causing an immersion of the basket in the coating material, the receptacle, the basket and the member being in coaxial alignment, and

upper end, a permeans for rotating the receptacle to cause a centrifuging of the residual material free from the basket and the objects therein into the enlarged portion of the receptacle anda rotation of the basket upon the reciprocal member.

6. In an apparatus for applying coating materialto objects, a rotatable receptacle containing coating material, means for immersing the objects to be coated in the material, means for rotating the receptacle to cause a centrifuging of the residual material free from the coated objects, and 1 means carried by the object immersing means for establishing a passage for dross in the coating material, such dross being directed thereto by the vortex created during the centrifuging action.

"I, In an apparatus for applying a metallic coating to objects, a rotatable receptacle containing a molten metal means for immersing the objects to be coated in the material and withdrawing them from the recefptacle, said latter means including a per ora'ted basket disposed in axial alignment with the receptacle, means for maintaining the metal in a molten state, means for rotatin the receptacle to cause a centrifuging of t 1e residual coating free from the basket and the coated objects, and an imperforate Wall tube carried coaxially in the basket, and open upper end of the tube disposed substantially at the normal level of the molten metal and. its lower end within an opening in the receptacle and provided with a erforated wall thereacross In witness whereof, I hereunto subsc'rib y my name this 14th day of November, A. 1)., 1928.

ARTHUR HERMAN- ADAMS.

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