Method and apparatus for applying wax to can ends

Claim 2

The method of claim 1 which further includes the step of postheating said can end after ejection of said melted wax onto said end to a temperature sufficient to retard and slow the setting of the wax on the end and to avoid crystallization and cracking of the wax.

Claim 3

The method of claim 1 wherein said rotating end is located a sufficient distance from said nozzle orifice to permit said ejected wax to atomize prior to contacting said end.

Claim 4

The method of claim 1 wherein said end to which said spray of wax is applied is located approximately 1 inch from said nozzle orifice.

Claim 5

The method of claim 1 wherein said wax is heated to a temperature of approximately 350* F. before it is supplied to the nozzle of said spray gun.

Claim 6

The method of claim 1 wherein said wax is supplied to said nozzle of said spray gun at a pressure in excess of 150 p.s.i. but less than 750 p.s.i.g.

Claim 7

The method of claim 1 wherein said wax is supplied to said nozzle of said spray gun at a pressure of approximately 400 p.s.i.g.

Claim 8

The method of claim 1 wherein said wax is ejected from a spray nozzle which has a flow rate of less than .160 gallons per minute water at 500 p.s.i.g. but more than .015 gallons per minute water at 500 p.s.i.g.

Claim 9

The method of claim 1 wherein said wax is ejected from a spray nozzle which has a flow rate of approximately .090 gallons per minute water at 500 p.s.i.g.

Claim 10

The method of claim 5 wherein said wax is heated to a temperature of approximateLy 350* F. before it is supplied to the nozzle of said spray gun.

Claim 11

The method of claim 11 wherein said wax is supplied to said nozzle of said spray gun at a pressure of approximately 400 p.s.i.g.

Claim 12

The method of claim 12 wherein said wax is ejected from a spray nozzle which has a flow rate of approximately .090 gallons per minute water at 500 p.s.i.g.

Claim 13

The method of claim 13 which further includes the step of preheating said can end to a temperature approximately the same as the melting temperature of said wax prior to ejecting said melted wax onto said end.

Claim 14

The method of claim 14 which further includes the step of postheating said can end after ejection of said melted wax onto said end to a temperature sufficient to retard and slow the setting of the wax on the end and to avoid crystallization and cracking of the wax.

Claim 15

Apparatus for applying less than 29 milligrams per square inch of a 100% solids protective layer of wax to the complete interior surface of a can end without the addition of any solvent so that the end need not be baked to drive off solvent from the wax, which apparatus comprises a spray gun having an airless spray nozzle and a nozzle orifice, means for supporting a can end for rotation relative to the orifice of said nozzle, means for melting a 100% solids wax and supplying it in the as melted condition to the nozzle of said spray gun without the addition of any solvent, means for ejecting said melted wax from said nozzle orifice at a pressure sufficient to cause said wax to atomize upon emergence from said nozzle and for directing said atomized spray onto a rotating end for a time period sufficiently short that less than 29 milligrams per square inch of wax is applied over the complete interior surface of said can end.

Claim 16

The apparatus of claim 16 which further includes means for preheating said can end to a temperature approximately the same as the melting temperature of said wax prior to ejecting said melted wax onto said end.

Claim 17

The apparatus of claim 16 which further comprises means for postheating said can ends after ejection of said melted wax onto said end to a temperature sufficient to retard and slow the setting of the wax on the end and to avoid crystallization and cracking of the wax.

Claim 18

The apparatus of claim 16 wherein said end supporting means is located sufficiently far from the nozzle orifice to permit said wax to atomize prior to contacting said end.

Claim 19

The apparatus of claim 16 wherein said can supporting means supports said end approximately 1 inch from said nozzle orifice.

Claim 20

The apparatus of claim 16 which further includes means to heat said wax to a temperature of approximately 350* F. before it is supplied to the nozzle of said spray gun.

Claim 21

The apparatus of claim 16 wherein said means for ejecting said melted wax from said nozzle includes means for supplying said wax to said nozzle at a pressure in excess of 150 p.s.i.g. but less than 750 p.s.i.g.

Claim 22

The apparatus of claim 16 wherein said means for ejecting said melted wax from said nozzle includes means for supplying said wax to said nozzle at a pressure of approximately 400 p.s.i.g.

Claim 23

The apparatus of claim 16 wherein said nozzle orifice has a flow rate of less than .160 gallons per minute water at 500 p.s.i.g. but more than .015 gallons per minute water at 500 p.s.i.g.

Claim 24

The apparatus of claim 16 wherein said nozzle orifice has a flow rate of approximately .090 gallons per minute water at 500 p.s.i.g.

Claim 25

The apparatus of claim 20 which further includes means to heat said wax to a temperature of approximately 350* F. and to maintain it at that temperature until it is supplied to the nozzle of said spray gun.

Claim 26

The apparatus of claim 26 wherein the means for ejecting said melted wax from said nozzle includes means for supplying said wax to thE nozzle at a pressure of approximately 400 p.s.i.g.

Claim 27

The apparatus of claim 27 wherein said nozzle orifice has a flow rate of approximately .090 gallons per minute water at 500 p.s.i.g.

Claim 28

The apparatus of claim 28 which further includes means for preheating said can end to a temperature approximately the same as the melting temperature of said wax prior to ejecting said melted wax onto said end.

Claim 29

The apparatus of claim 29 which further comprises means for postheating said can ends after ejection of said melted wax onto said end to a temperature sufficient to retard and slow the setting of the wax on the end and to avoid crystallization and cracking of the wax.

Claim 30

The apparatus of claim 30 wherein said spray gun includes a restrictor plate located upstream from said nozzle orifice, said plate having a restricted axial aperture approximately .008 inch in diameter.