Drying Apparatus

Abstract

An apparatus for and method of drying articles such as tubular containers each having a bottom wall, an adjoining sidewall, and an open end wherein said containers are supported in an inverted position and a drying gas moved therepast in such a manner that it circulates around and within the containers and provides efficient drying of both the interiors and exteriors thereof.

Description

BACKGROUND OF THE INVENTION

Many apparatus and methods have been proposed heretofore for drying tubular containers, such as cans each having one open end, for example, by passing a drying gas thereover. However, such previously proposed apparatus and methods do not provide efficient drying of the interiors of such cans because of their inability to circulate the drying gas inside each can.

SUMMARY

This invention provides an improved apparatus for and method of drying articles such as tubular containers each having a bottom wall, an adjoining sidewall, and an open end wherein said containers are supported in an inverted position and a drying gas circulated therepast in such a manner as to provide efficient drying of the exteriors thereof while simultaneously providing circulation of such drying gas within each container to also provide efficient drying of the interiors thereof.

Other details, uses, and advantages of this invention will become apparent as the following description of the exemplary embodiment thereof presented in the accompanying drawings proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings show a present exemplary embodiment of this invention, in which:

FIG. 1 is a perspective view with parts broken away illustrating one exemplary embodiment of the apparatus of this invention used to dry tubular containers each having only one open end;

FIG. 2 is a view taken essentially on the line 2-2 of FIG. 1;

FIG. 3 is a greatly enlarged fragmentary perspective view of a portion of the conveyor comprising the apparatus of FIG. 1;

FIG. 4 is a side elevation with parts broken away of the apparatus of FIG. 1 particularly highlighting the method utilized to circulate a drying gas over the containers;

FIG. 5 is a greatly enlarged fragmentary view taken essentially on the line 5-5 of FIG. 4; and

FIG. 6 is a greatly enlarged fragmentary view with an exaggerated spacing between containers particularly illustrating the manner in which a drying gas is circulated past a plurality of inverted containers to provide rapid and efficient drying of both the interiors and exteriors thereof while providing circulation of gas within each inverted container.

DESCRIPTION OF ILLUSTRATED EMBODIMENT

Reference is now made to FIGS. 1--3 of the drawings which illustrate one exemplary embodiment of the apparatus and method of this invention which is designated generally by the reference numeral 20. The apparatus 20 comprises an endless chain conveyor 21 which has a maximum open area which allows substantially unobstructed flow therethrough of a drying gas in a direction perpendicular to its supporting surface. The conveyor 21 has a horizontally extending portion 22 which is adapted to support a plurality of elongated tubular articles shown as a plurality of tubular containers or cans 23 each having a bottom wall 24 and an adjoining sidewall 25 terminating in an end edge 26 defining an open end, see FIG. 6.

The cans 23 are supported on the horizontally extending portion 22 of the conveyor 21 with their axes arranged vertically and in parallel relation. A system is provided for circulating a drying gas or fluid, heated air in this example of the invention, around the cans 23 so as to provide efficient simultaneous drying of both the interiors and exteriors of such cans.

The apparatus 20 has means for directing the drying air, indicated in the drawings by a plurality of arrows 30, so that the air is directed toward the cans 23 at high velocity and in a plurality of closely spaced jets, with the spacing between such jets assuring that at least one jet is directed normally toward each of the cans 23 and in particular substantially toward the central portion of the bottom wall 24 of each can 23. The apparatus 20 has means for dampening any turbulence in the heated air as it approaches the cans 23 and in this example of the invention the dampening means comprises a plurality of sets 31 of screen and plate assemblies arranged parallel to the horizontal portion 22 of the conveyor 21 and with each set being defined by a perforated plate 32 adjoined by a screen 33 arranged upstream thereof. The apparatus 20 also has a planar sheet 34 which has a plurality of spaced openings 35 provided therein and the openings 35 define the previously mentioned jets which assure that heated air is directed toward the cans 23 at high velocity.

The apparatus 20 also has a flow control device arranged beneath the horizontal portion 22 of conveyor 21 which is used to create a negative pressure beneath the conveyor and cans 23 and in this example of the invention such flow control device comprises a plate 36 having a plurality of apertures 37 therein. The plate 36 with its apertures 37 operates to restrict airflow in a controlled manner creating a venturi effect which causes heated air to circulate inside the inverted cans 23 and provide an efficient drying of the can interiors. It will also be appreciated that the construction of the conveyor 21 may be such that it cooperates with the plate 36 to provide controlled flow producing the above-mentioned venturi effect.

The apparatus 20 has what will be referred to as a drying chamber 40 defined by a housing 41 which has openings 42 and 43 at opposite ends thereof which allow the conveyor 21 with the cans 23 supported thereon in an inverted manner to pass through the chamber 40 in a continuous manner to enable high-speed drying thereof. The housing portion 41 and hence drying chamber 40 is supported on an associated supporting floor by a plurality of spaced vertical legs 44.

The apparatus 20 also includes a duct assembly 45 arranged beneath the housing portion 41 and the assembly 45 has an upstream end fastened in sealed relation to the housing portion 41 and a downstream end fastened in sealed relation to the inlet of a centrifugal fan 46. The apparatus 20 also has a duct assembly 48 which includes a vertically extending portion 50 which is fastened in sealed relation to the discharge of the fan 46, a vertical downwardly flaring frustopyramidal section 51 fastened in sealed relation to the top portion of the housing 41 and a substantially U-shaped transition section 52 connecting the vertical sections 50 and 51.

The fan 46 has a shaft 53 extending therefrom which is supported by a pair of antifriction bearings 54 carried on a support 55 and the shaft 53 is driven by a suitable drive motor 56. The apparatus 20 has a plurality of heaters 57 which may be in the form of electrical heaters which are provided with electrical power from any suitable power source and are utilized to heat the air which is used to dry the cans 23.

As will be apparent particularly from FIG. 4 of the drawings, the air circulating system for the apparatus 20 comprises a closed loop system which circulates heated air past the containers 23 in the drying chamber 40. The air is then recirculated past the heaters 57 to remove any moisture that may be present therein. In addition, suitable air temperature control devices may be arranged downstream of the heaters 57 and used to control such heaters and hence the temperature of the heated air to provide optimum drying efficiency.

The cans 23 which are to be dried are moved from a can washer, for example, in an inverted position and placed on the horizontally extending portion 22 of the conveyor 21 so that they may be moved through the drying chamber 40. Any suitable technique may be utilized to place the cans 23 on the conveyor 22 such as by manual or automatic means. For example, an endless conveyor 60 may be used to move washed cans from a can washer 61, see FIG. 2, to a transfer mechanism such as a horizontally reciprocating plate assembly 62 which transfers the cans onto the horizontal portion 22 of the conveyor 21. It will also be appreciated that the conveyor 21 may also be provided so that the horizontally arranged portion 22 extends completely through the washer thus eliminating the need to provide a separate conveyor from the washer 61 and a device to transfer the cans from the washer conveyor to the conveyor 21.

As the cans 23 are moved through the drying chamber 40 the high velocity jets of air defined by the openings 35 in the sheet 34 impinge downwardly against the bottom walls 24 of the cans 23 while sweeping past the sidewalls 25 at a sufficiently high velocity to provide efficient transfer of heat to and hence drying of the sidewalls. As the air sweeps past the cans 23, the plate 36 with its apertures 37 helps control the airflow and causes a negative pressure in a chamber 63 defined beneath the plate 36 so as to provide the previously mentioned venturi effect causing circulation of the heated air within each can 23 and as indicated in a somewhat exaggerated manner by the arrows 64 and 65 in FIG. 6 of the drawings.

Thus, it will be seen that the high velocity heated air bathes the outside of each can 23 while the components of the apparatus 20 cooperate to provide circulation of heated air within each can 23 whereby efficient drying of both the interiors and exteriors of the cans 23 is provided. In addition, the airflow is such that the cans 23 are maintained in their upright positions as they pass through the drying chamber 40.

The conveyor 21 comprising the apparatus 20 has been described as a chain conveyor having a maximum open area which enables substantially unobstructed airflow therethrough. The conveyor 21 comprises a plurality of links 66 each having an undulating configuration essentially as shown in FIG. 3 with each pair of adjoining links being held together by an elongated rod 67 which may extend across the full width of the conveyor 21. The individual links 66 and their rods 67 may be made of any suitable corrosion resistant material such as stainless steel or a plastic material. Yet, the construction of the conveyor 21 is such that it may be moved in a continuous endless path.

The conveyor 21 is supported by a plurality of toothed rollers 68 which have cooperating teeth which are received within openings 70 defined between adjacent chain links 66. One of the rollers 68, shown as the upper left-hand roller in FIG. 2 and indicated at 71 is driven by a suitable drive motor to enable movement of the conveyor 21 in an endless path.

The plate 36 with its apertures or openings 37 is supported beneath the horizontal portion 22 of the conveyor 21 in any suitable manner. However, in this example of the invention the plate 36 is in the form of a support plate which is suitably fixed to the legs 44 and has a top surface which supports the horizontal portion 22 for sliding movement thereacross with minimum frictional drag while assuring that each can 23 is supported on its associated end edge 26 with optimum stability.

To minimize the frictional drag between the conveyor and the plate the conveyor 21 and/or plate 36 may have their rubbing surface portions either made of or treated with suitable antifriction materials. In addition, elongated narrow strips made of an antifriction material may be fixed on the plate 36 to reduce the rubbing area.

As previously mentioned a plurality of dampening assembly 31 is provided for dampening any turbulence in the heated air as it approaches the cans 23 and each dampening assembly is comprised of a plate 32 adjoined by a screen 33. Each plate 32 preferably has a plurality of openings 72 provided therein while each screen 33 is in the form of a large mesh screen defined by a plurality of crisscrossed undulating wires 73 which, due to the undulating character thereof, help minimize any turbulence in the flow of heated air as it approaches the planar sheet 34 and thereby assures the provision of uniformly spaced high velocity jets of air exiting the lower surface of the plate 34 toward the cans 23, see FIG. 4.

As will be apparent from FIG. 6 of the drawings, each bottom wall 24 of each exemplary can 23 has an outwardly concave recess or depression 74 defined therein and with the cans moving into the drying apparatus 20 from an associated washer in an inverted position washing fluid, such as water, for example, is contained in each depression 74. However, the area of each opening 35 and the spacing between openings is correlated with the diameter of the cans 23 to assure that at least one jet of heated air is directed substantially normally, i.e., perpendicularly, toward the bottom wall 24 of each can 23. Thus, with the presence of a washing fluid, such as water, within a depression 74 it will be seen that the jet of air impinging thereagainst displaces the washing fluid from within the depression and downwardly along the associated sidewall 25 whereupon the high velocity heated air provides rapid drying of the bottom wall 24 and sidewall 25.

As previously indicated, the cooperating arrangement of the openings 35 in sheet 34 and the apertures 37 in the plate 36 together with the circulation of heated air as provided by the fan 46 results in the provision of a positive pressure ranging roughly between one-fourth and one-half inch of water in the drying chamber 40 immediately above the sheet 34 whereby a negative pressure ranging roughly between 1/2 inch and 2 inches of water is provided in the chamber 63 immediately beneath plate 36. This pressure distribution and the cooperating arrangement of components is such that the cans 23 are maintained in a stable upright manner, yet an efficient drying is provided by air flowing inside of and around such cans.

The sheet or plate 34 is positioned a controlled distance above the bottom walls 24 of the cans 23 and as indicated at 75 in FIG. 6. Suitable means may be provided in the housing 41 to assure that the sheet 34 may be moved to accommodate cans of different heights and thereby assure impingement of air at high velocity against the bottom walls of the cans 23 as well as high velocity flow along the sidewalls of such cans. It will also be appreciated that with the apparatus and method of this invention the cans 23 may be packed tightly with their sidewalls 23 substantially in adjoining relation during movement thereof by the conveyor 21 through the drying chamber 40. With the cans tightly packed there is less area between adjacent cans which causes higher velocity airflow along the sidewalls of the cans 23 whereby more efficient heat transfer is provided and hence more rapid and efficient drying of the particular cans. In particular, using the standard 12 fluid oz. beverage can of circular cross-sectional configuration the effective area between cans is roughly 10 percent of the total available supporting area of the horizontal portion 22 of belt 21 which is within the chamber 40, for example. This 10 percent area assures high velocity flow and efficient heat transfer.

The presentation of FIG. 6 has been made with the cans 23 arranged in widely spaced relation to demonstrate the action that takes place whereby air is circulated at high velocity around the exteriors of the cans and within the inverted cans to provide efficient high speed drying. An efficient high speed drying action takes place which is made possible by both convection and conduction and irrespective of whether the cans are widely spaced as much as or more than shown in FIG. 6 or are packed tightly together.

While a present exemplary embodiment of this invention, and method of practicing the same, has been illustrated and described, it will be recognized that this invention may be otherwise variously embodied and practiced by those skilled in the art.

Claims

I claim:

1. An apparatus for drying elongated tubular articles comprising, a conveyor for supporting said articles with their axes arranged vertically and in parallel relation while allowing substantially unobstructed gas flow therethrough in a direction perpendicular to its supporting surface, a system for circulating a drying gas around said articles and then toward said conveyor, means for dampening any turbulence in said drying gas as it approaches said articles, and means directing said drying gas toward said articles at high velocity and in a plurality of closely spaced jets with the spacing between jets assuring that at least one jet is directed normally toward each of said articles.

2. An apparatus as set forth in claim 1 in which said directing means comprises a planar sheet having a plurality of spaced openings provided therein defining said plurality of jets, said sheet being arranged parallel to said conveyor and between said dampening means and said articles.

3. An apparatus as set forth in claim 1 in which said dampening means comprises a plurality of screens arranged parallel to said conveyor.

4. An apparatus as set forth in claim 1 in which said directing means comprises a planar sheet having a plurality of openings therein defining said plurality of jets and said dampening means comprises a screen arranged above and parallel to said planar sheet, said screen being defined by a plurality of crisscrossed undulating wires which help minimize any turbulence in the flow of said drying gas as it approaches said planar sheet.

5. An apparatus as set forth in claim 4 and further comprising a flow control device arranged beneath said conveyor and defining spaced apertures beneath said articles, said control device and directing means assuring that each of said articles is maintained in an upright manner with said drying gas being circulated past each article at high velocity to thereby provide efficient transfer of heat to each article and drying thereof.

6. An apparatus as set forth in claim 1 in which each of said articles has a sidewall provided with opposed end edges and a wall arranged intermediate said end edges, and further comprising a flow control device arranged beneath said conveyor and defining spaced apertures beneath said articles, said control device and directing means assuring that each of said articles is maintained in an upright manner with said drying gas being circulated past each sidewall at high velocity to thereby provide efficient transfer of heat to said sidewall and simultaneously provide a negative pressure beneath each article and circulation of said drying gas within each article beneath its transverse wall to enable rapid drying of both the interior and exterior of each article.

7. An apparatus as set forth in claim 6 in which said flow control device comprises a stationary planar support supporting said conveyor for movement thereon, said support having said spaced apertures provided therein.

8. An apparatus for drying tubular containers each having a bottom wall and an adjoining sidewall terminating in an end edge defining an open end, said apparatus comprising, a conveyor for supporting each container in an inverted manner with its end edge resting on said conveyor, said conveyor allowing substantially unobstructed gas flow therethrough in a direction perpendicular to its supporting surface, a system for circulating a drying gas against the bottom wall of each container and around its sidewall and then toward said conveyor, means directing said drying gas toward said containers at high velocity and in a plurality of closely spaced jets with the spacing between jets assuring that at least one jet is directed normally toward each of said containers, and a flow control device arranged beneath a horizontal portion of said conveyor and defining spaced apertures beneath said containers, said flow control device and directing means assuring that each of said containers is maintained in an upright manner, said drying gas being circulated past each sidewall at high velocity to thereby provide efficient transfer of heat to each sidewall and simultaneously provide a negative pressure beneath each container and circulation of said drying gas within each container to enable rapid drying of both the interior and exterior of each container.

9. An apparatus as set forth in claim 8 in which said circulating system comprises a system for circulating heated air with said circulating system, directing means, and flow control device cooperating to provide a venturi effect which causes said negative pressure and said circulation of heated air within each container.

10. An apparatus as set forth in claim 9 and further comprising means for dampening any turbulence in said drying gas, said dampening means being arranged upstream of said directing means.

11. An apparatus as set forth in claim 10 in which said negative pressure ranges between roughly 1/2 inch to 2 inches of water which assures each of said containers is held in a stable upright manner while providing efficient drying of the interior thereof.

12. An apparatus as set forth in claim 10 in which said flow control device comprises a stationary planar member supported beneath said horizontal portion of said conveyor, said support having said spaced apertures provided therein.

13. An apparatus as set forth in claim 10 in which said directing means comprises a planar sheet arranged parallel to said conveyor and having a plurality of spaced openings provided therein defining said plurality of jets.

14. An apparatus as set forth in claim 13 in which said dampening means comprises a plurality of sets of screen and plate assemblies arranged parallel to said horizontal portion of said conveyor, each of said sets being defined by a perforated plate and an adjoining screen arranged upstream thereof.

15. An apparatus as set forth in claim 14 in which each of said screens is defined by a plurality of crisscrossed undulating wires which also help minimize any turbulence in the flow of said heated air.

16. An apparatus as set forth in claim 9 in which said conveyor comprises an endless chain link conveyor and said circulating system comprises a closed loop system which reheats and recirculates the air past the containers being dried by said apparatus.

17. An apparatus as set forth in claim 9 in which each bottom wall of each container has an outwardly concave depression defined therein and with said containers moving from a washer to said apparatus in an inverted manner washing fluid is contained in said depression, and with said directing means assuring that at least one jet of air is directed normally toward each container the washing fluid is displaced from within its depression by the action of an associated jet of air while the associated container is maintained in an upright position.