US2375173A - Apparatus for drying metallic articles - Google Patents

Description

May l, 1945. A. |y BUNTING ET AL 2,375,173

n APIARATUS FOR DRYING METALLIC ARTICLES Filed April 10, 1942 4 Sheets-Sheet l f my ff 21 TTORNE Ys.

May l, i945 A L BUNTINGFET AL 2,37573 APPARTUS FOR DRYING METALLIC ARTICLES Y Filed April 10, 1942 4 sheefshe'ef 2 NVENTORS. vizi? JA/M ATTORNE Ys.

May l, 194.5-4 A. L. BUNTING E1- AL 2,375,173

n APPARATUS FOR DRYING METALLIC ARTICLES Filed April 1o, 1942 4 sheets-sheet s T T ORNE 17'5.

May l, l1945.

lA. l.. BUNTING ETAL APPARATUS FOR DRYING METALLIC ARTICLES 4 Sheets-Sheet 4 Filed April lO, 1942 LRS.

`atented ay l, w45

sA'rss- AENT,

APPARATUS Foa -pierino. Mamme Aa'rioms .Alberta Bunting, Dearborn, and Arthur c. Schultz, Detroit, Mich.; said Schultz assignor to said Bunting Application April 10, 1942, Serial No.`f138,408

i claim. i(ci. :ii-69)' The present invention relates to apparatus for drying metallic articles, relating more particularly to apparatus `for bakingA or hardening protective coatings onL articles fabricated .from y metals subject to rusting or corrosion.

T11-applying most protective coatings to articles y formed of steel or similar metals subject to cor- Coatings completely satisfying all of the afore A said conditions have not been produced to date chley because of ineffective or faulty coating apparatus-especially because of ineffective or faulty baking and drying operations attempted to be carried out by such apparatus.

It is, therefore, one object of the present in. vention to provide improved apparatus for drying metallic articles, said apparatus being adapted to eiectively air dry and/or bake coate ings such, for instance, as coatings comprising polymerized resinous products or enamel-like coatings for protecting articles subject to rusting or corrosion.

Itis another object of the invention to provide apparatus of the aforesaid general character in which an air-drying operation may be followed by a baking operation, both of these operations being adjustable and controllable in an improved manner, especially as to temperatures and times of treatment, in order that the 'optimum conditions maybe provided for' the particular coating utilized.

Another object of the invention is to provide apparatus for air drying and/or baking protective coatings for the aforesaid articles and which is adapted to provide an even, smooth finish coating, free from wrinkles, sags and blisters and to provide such a finish Coating whether the initial .coating material utilized prior to the drying Other objects and advantages of this inv en tion `will appear in the following description and appended.claim, reference being had to the accompanying. drawings'forming a part of this speciilcation,l wherein like reference characters designate corresponding parts in the several views.

. In said drawings: v r

Fig. 1 is'a side elevation of one form of appal ratus embodying lther present invention. For

present purposes, that portion of the apparatus shown at the right side of Fig. 1 is referred to as the front of the apparatus, while that portion shown at'the left side of Fig. 1 is designated as the rear. y v

Fig. 2 is a partial'cross-sectional view taken along the line 2--2 of Fig. l in the direction.

of the arrows, parts being broken away to show the interior of the apparatus.

Figs. 3 and 4 are, respectively, front and rear elevational views-of the form of the apparatus shown in Fig. 1. l

Fig. v5 is la sideI elevation of a part of the apparatus shown in Fig. 1, but shows the opposite side from that-shown in Fig. 1.4

" Fig. 6 is a detailed view of a part of the air 'tunnel utilized in connection with the present invention and shows in particular one form of a device for removing 'drops from the article to be I shows a 'modiiication of 'the device shown in Fig. 6.

Fig. 9 is a cross-sectional view taken along the the apparatus showing one. form of mechanism for automatically dipping the metallic articles.

15 is aview similar to Fig. 14 but showing another form of automatic dipping mechanism.

" Before explaining in detaill the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated inthe accompanying drawings, since the invention is capable of other embodiments and of beingprac-l ticed or carried out in various ways. Also it is to A be understood that the phraseology or terminology employed herein is for the'purpose of description and not of limitation. v.

For convenience in understanding, at the outset,

' the principal elements of the embodiment of the invention shown in the drawings, a. brief general explanation of these elements follows, details .thereof being set forth hereinafter. Referring to said drawings, and especially to Fig. l, the reference numeral 2t) indicates an inclined air-drying enclosure or tunnel which opens at its upper or inner end into a generally vertically positioned enwith the air-drying operation.

closure or chamber 2l also utilized in connection The reference numeral 22 indicates in general an oven utilized for the baking operation. As best shown in Fig. 2,

the oven 22 is separated from the chamber 2| by a suitable partition 23 and communicates with said l oven by means of an opening 24 extending across the width of the oven and the chamber 2|, said opening being positioned near the bottom of the apparatus. The oven 22. is heated by hot air supplied by a heating and blowing unit indicated in general by the reference numeral (Figs. 3 and 4), the hotl air supplied by said unit being-con ducted to the oven by means of a duct 26. As best4 shown in Fig. 1, a continuous chain conveyor is provided in the apparatus and is adapted to conduct the articles to be coated through the air-drying tunnel 20, the chamber 2i and thence through the oven 22, After being so conducted through the air-drying tunnel, the chamber and the oven,

` the articles are conducted by the chain conveying system out ,of the oven at the rear of the apparatus (see Fig. 4) and may then be removed from the apparatus. Thevarious devices shown in Figs. 6 to 13 inclusive for removing drops from the objects to be coated are positioned vin the air tunnel 2|) preferably, but not necessarily, at the lower front end thereof. The structure and operation ofthese `devices is explained fully hereinafter. A

Referring to the aforesaid apparatus in greater detail, the air-drying tunnel 20 is dimensioned and shaped to receive the object or objects to be coated. For instance, in the form ci' the invention shownv in 'the accompanying drawings the air tunnel 20 is generally rectangular in cross section as best shown in Fig. 2 and its height is arranged so that the ice trays 21 may be received 'within the tunnel 25 and carried therethrough by the chain conveyor system explained hereinafter. Vwidth of the air tlmnel 23 is such that a plurality The 'of these ice trays may extend across the width of the tunnelin the manner clearly indicated in the drawings in Figs. 3 andl 4. The air tunnel 20 is` gether and separated by suitable generally verti-A cally positicned spaced side angle irons or supports 33-33.- Inthe particular form of the tunnel 2|J` shown in the drawings, especially Fig. 2, it will be lnoted that the bottom member, is placed over the .lower supporting longitudinal angle iron v32- 32 so'that the side angle iron 33-33 extends through openings inthe bottonrmember 3|).- We` have found this to be a'desirable construction and it will be understood that the tunnel 20 may bev formed of suitable top, side and bottom members supported by and attached to a suitable frame work in several satisfactory ways which will readf ily occur to one skilled in the art.

The entire tunnel structure 20 comprising top, side and bottom members 28, 29 and 30 and the framework consisting of the angle irons 3|, 32 and 33, is supported by a suitable supporting framework in the manner best indicated in Fig'l. As there shown, this supporting lframework comprises generally longitudinal horizontally extending side frame members 36 to which is fixed a number of spaced generally upright supporting members 35 which are also fixed to the bottom supporting rail 32 of the tunnel 2li. As indicated in Fig. l. the supporting members 35 are so arranged with respect to their height that the tunnel 20 is maintained at an upward inclination.

The tunnel 20 communicates with or leads into the generally upright enclosure or chamber 2 I. This chamber 2| is formed by side panels 36 and 31 (Figs. 1 and 5) formed of sheet metal or thelike. The front of the chamber or enclosure 2| comprises a generally similar panel 38 (Fig. 2) and the rear of the chamber 2| is formed by a similar panel 23 which separates the chamber 2| from the oven 22. As pointed out hereinbeiore, this partition does not extend to the bottom of the device, thereby providing an opening 24 to permit;J communication between the oven 22, chamber 2| and tunnel 2i).A As best indicated in Figs. 2 and 5, the side walls 36 and 31 are supported by and attached to supporting members 35 (Fig. 2) at the front and to generally similar supportingmembers 39 (Figsrl and 5) at the rear. The front panel extends between the spaced members 35-35 (Fig. 2) while the rear panel extends between the spaced members 39-39. The top of the chamber is closed by a suitable top member shown at #0 (Figs. 1 and'). As indicated in the drawings and in particular in Fig. l, the framework for'the enclosure 2| is supported by and is attached to the longitudinally extending rails 36-34.

The oven 22A includes of angle irons or generally similar supporting members and the laterally spaced members f 39?-39 form the front upright members of this framework. These members are attached to suitable longitudinally parallel and spaced bottom frame members lil-5|. At the rear of the oven thereis provided a pair of laterally spaced upright frame members 42--52 (Fig. 4) and a pair of top frame members 43-'43 (Figs. l and 5) extendingbetween theupright frame members 39 and 40 completes the outline of this framework. Suitable cross frame members such as 1 those shown at M- (Fig. i) may be utilized to apparatus in the manner indicated hereinafter. e The oven is enclosed by'providing sheet metal to form lthe front wall of the oven and separatev strengthen the framework and for the purpose of attaching various working parts of the presentsides 45 and 48 and the partition or ,wall 23 serves the oven from the enclosure or chamber 2| in they manner indicated hereinbefore.

-As best shown in Figs. l and 5f the oven22 is formed at the rear to' provide a stepped section indicated in general at "J This section 41 is formed of suitable sheet metal side and end pieces supported by and attached to suitable frame members in 'the same general manner as the A other side and endpieces of. the oven described in detailhereinbefore. As also shown in Figs. 1

' and 5, the top of the stepped section is left open..

a framework consisting I In fact ka portion of the stepped section shown at 48 provides-an open top part for the chain `conveyor system explained hereinafter to emerge from the oven and the open top part of the stepped 4section shown at 49 permits the chain conveyor system to reenter the apparatus. The objects carried through the apparatus by the chain conveyor system may be removed from the apparatus when they have been carried down the chain conveyor after it has emerged from the point marked 138 and before it reaches the point marked' 49.

Referring in greater detail to this chain conveyor system, it will be noted that itl is arranged on sprockets placed throughout the device. This chain conveyor system in general possesses two continuous parallel spaced chains running over the sprockets, said chains being connected by bars or supports from which the objects to be carried through the apparatus are hung or suspend.

ed in the manner best shown in Fig. 3. Thus, this chain conveyor comprises chains 50 and 5| running over suitable sprockets not shown) in the air tunnel 20, continuing through the tunnel and over a sprocket 52 located at the top thereof. After passing over the sprocket 52 the chain conveyor continues downwardly throughout the chamber 2i, passes over the sprocket 53 and thence over a series of sprockets arranged so that the chain conveyor passes up and down several times through the oven in the manner clearly shown in Fig. l. After passing about the last sprocket in the'oven, which is the sprocket shown at 5t. the chain conveyor passes around the sprocket 55 which` is located immediately above the opening i8 whereby the chain emerges from the oven, passes about the sprocket 55 down through the opening shown at t8 and thence about the sprocket 56. lThereafter it continues in the manner clearly shown in Fig. 1 until it again passes around the sprocket 52 whereupon the cycle is repeated. It.will be understood that this chain is a continuous system.. The chains 5B and 5l are kept taut by a spring sprocket shown at 5l' (Fig. 1) which comprises a sprocket arranged to slide relative to a support such as the support 35 against the tension of a spring in order that .the chain will at all times be lkept taut to insure smooth and proper operation of the chain conveyor system. This chain conveyor system Vis driven by suitable m'eans such as the mo tor 58 (Figs. 3, 4 and 5) which may dr-ive the chain conveyor system through suitable gears 59. If desired a gear reduction means siich as a reducing gear boX may be interposed between the motor 58 and the driving gears 59 of the chain conveyor system, if it is desired to reduce the speed of the chain conveyor.

The oven 22 is heated by a 'ow of heated air provided'by a suitable heater and blower unit such as the unit shown in general at 25. In the form of the apparatus shown in the drawings, this unit includesan oil burner 6D which may beof any suitable design. This unit also includes a suitable blowing mechanism such as that shown at 6l which is driven by the motor 62 (Fig. 4)..

The stack 80 is provided'for use in connection with the oil burner 60. Air is drawn into thev heating and blowing unit by means of the blower 6l, is heated by means of the oil burner eiland is conducted tothe oven by means of the air duct 26.

goes through or spreads throughout the interior of the oven and thence is removed through said air duct 63 and returns to the heating and blower unit 25 where it is reheatedand recycled back through the oven 22. It will be noted,l that the return air duct 63 enters the oven at the bottom portion thereof at two different points 64 and 62a (Figs. 1 and 5) and accordingly that.the air duct 63 is divided into two sections in the manner clearly indicated in the drawings and in particular in Fig. 5.

It will be understood that the air introduced into the oven 22 from the heater and blower unit 25 not only serves to maintain the oven at the desired temperatures but some of this heated air ows outwardly through the opening 2li (Fig. 2) between the oven 22 and the chamber 2|,.-and flows upwardly through the chamber 2l and thence downwardly throughout the inclined tunnel 20. Thus, but a portion of the air is recycled through the return air duct 63.

It will be understood that the temperature of the oven 22 is readily controlled at suitable ther inostats located in the oven and/or within the air duct 26 so that the heater or blower unit is operated as desired to producea flow of heated air into the oven at the desired temperatures and in the desired amounts.

The operation of the present apparatus is believed lto be clear from the foregoing description of this apparatus. However, it will be readily understood that the object to be treated in the present apparatus, such as the ice trays 2l, are' hung from the bars or supports between the chains and 5l in the manner best shown in Figs. 1 and 3. They are then conveyed through the air drying tunnel 2|), through the chamber 2 l thence several times through the oven 22 ourl of the oven 22 at the point i8 and are removed from vthe chain conveyor, by suitable means, when traveling from the sprocket to the point 69.

It will thus be understood that the said objects are first air dried by traveling through the tunnel 20 and the chamber 2i and afterwards are baked in the oven 22. By controlling the rate of speed tunnel 2|] and chamber 2l may be suitable for the particular coating utilized for protectively coatingo the objects carried through the apparatus.

, Referring now to the various devices for removing drops from the objects carried through the apparatus and whichare shown in Figs. 6 to 13 inclusive, these devices are preferably located in the air-drying tunnel 2l) preferably within the bottom thereof. For example, the device 'shown in Figs. 6 andl'l may be positioned within the bottom 30 of the air-drying tunnel 20. This device consists of a plurality of generally flat topped elongated' finger-like members 65-65 1 which are spaced relatively closely together side by side on a. shaft 66. Between these elongated members 65 are Washers 67 and the elongated members 65 are free to move relative'to the shaft 66, but due tothe washers andthe spring 68 (Fig. 7) are frictionally held on the shaft; Accorddingly, when the shaft 66 is driven, as by the motor 69, the lingers are tipped upwardly in the manner shown in Fig. 7 and are maintained inl that position since the shaft is free to turn rela- `covered with a suitable absorbing material 1li such as paper or the like. After the fingers S have been contacted by the trays moving through the tunnel 2D, they are returned to their initial upwardly extending position by means of the rotating shaft 66.

Ii" desired, a generally similar arrangement may be utilized except that the ilngers B5 are not motor driven to be returned, but are `so arranged that they return by gravity. Such a modication is shown in Figs'. 8 and 9. As there shown, particularly in Fig. 9, the fingers 65 are constructed and shaped so that the shaft is placed on center relative to them, whereby the tray 21 will touch the top ofthe upwardly extending top of the fingers 65, tipping them about the shaft 55. After the lingers' 65 have been so tipped, they will return to their normal positions through gravity due to the off-center position of the shaft 5S relative to the pointsof the fingers 65.

Still another modification of a drop removing means is indicated in Fig. 13. As there indicated,

instead of the lingers 55 there is provided a series oi spring clips 1l which are retained in a desired "upward generally inwardly extending positionl within the tunnel 2B by means of the retaining clip 12. As the tray 21 passes through the tunnel 2t it contacts the spring clip 1l, which is depressed, permitting the tray to pass through the tunnel, 2i) and at the same time removing excess drops from the .tray 21. After this takes place, the spring clip '1i springs back into its original position. As in the other devices shown in Figs. 6 to 9, inclusive, the spring clip Il may contain a suitable absorbing material 10 at its contact point.

n1 Fig. 1o there is mostrate@ sun another means for removing drops from the obiectsor trays conveyed through the air-drying tunnel 2B.

As thereshown, a, suitable roller 13 is provided which extends .across the air-drying tunnel 29 immediately above the bottom 30 thereof. "I'his roller is placed on a shaft 1d which in turn extends through suitable bearings 15-15 and is driven as by a motor. Also, there isv provided a member 16 which is attached in any suitable .manner beneath the roller 13, such as being attaehedto the bearings 18-18 andto the bottom an of the air-drying tunnel zo 1n the manner mdicated in Fig. 10. This member'lG is bent so as to form a. tray-likel part beneathr the roller 13 and may be lled with a solvent for the coating .material used on the objects carried through the apparatus. Thus it will be seen that as the ob- `jects are carried `through the air-drying tunnel Zlby the chain conveying system they are contacted by the rotating roller 13 which removes drops and excessive coating Vmaterial from saidobjects. As the material accumulates on the roller, it will be seen that the roller rotates. through the solvent carried in the trayformed by the member 'IGso that this accumulated material is `removed fromv'the roller and may-be reclaimed later from 'the solvent.

. In Figs. 11 and l2 thereris illustrated still an-x other modication for removing the excess drops As the metallic objects are carried across thev y on the objects carried through the air-drying tunnel. This device consists of a-series of electromagnets 11-11 which are positioned to extend across the width of the bottom 3d oi the airdrying tunnel 2U in the manner shown in Fig. ll. Of course, these magnets are connected by suitable conductors to a source of electrical energy.

ield of the magnets, it will be seen that `these magnets cause a vibration of said objects and thereby shake free of the obliect all excessive coating material or drops therefrom. Due to the inclination of the air-drying tunnel 2d this ma terial will dow down the bottom 3d thereof and may be removed therefrom or collected at the end thereof in any-suitable manner. It will be appreciated 'that the current sent through the electromagnets' is preferably alternating current, thereby setting up continuously changing magnetic fields which cause this vibration of the trays as they pass over the magnets.

In place of or additionally to the foregoing means for removing drops or excessive material from the objects, the bars or supports between the chains El) and 5i may be movable relative to the chains or may be formed of a resilient material, Thus the objects hung therefrom or supported thereby are' shaken as they are conveyed through the apparatus; lf desired, the chain conveyor may be operated intermittently at an increased or decreased speed to' provide a series of jerky movements to aid in shaking said drops or excessive coating materialfrom the objects.

Figs. 14 and l5 illustrate modications of the present apparatus providing for automatic dipping of the metallic articles, such as the ice trays 21, in a coating mater-iai prior to the air drying and baking operations carried out by the present apparatus and described hereinbefore.

Referring to Fig. 14, the modification there shown possesses an extension a of the bottom rails 34, to which upstanding frame members 8l and 82 are attached by suitable means. A cross frame member 83 'extends between the members di and 82 at the top thereof. To the upstanding member 32 is attached a container 8E having a generally rearwardly extending lip portion 85. As illustrated in Fig. 14, the chain conveyor 50 instead of coming up directly to the sprocket 58a. and then extending through the air drying tunnel 20, extends along the length of the extended rail 35 past the portion 35a thereof, thence about the sprocket 85 upwardly aboutthe sprocket 81 and then downwardly around a sprocket 88 suitably maintained within theupper portion of Y the' container Se. The chain 50 after continuing about the sprocket 88 thencontinuesout of the container 84 upwardly at` Van angle around the sprocket 89, thence downwardly around the sprocket 90, over the sprocket 50a, and continues upwardly through the air drying tunnel'20 as described hereinbefore.

.The 4container' is lined, or partially filled as the circumstances dictate, with a coating materialto be air dried and bakedonv the article in 'accordance with the present disclosure. Accordingly, thearticle such as the ice trays 21 are conducted by the conveyorin the direction shown on the arrows in Fig. 14, that is, they are consprocket 89 is so positioned relative to the sprocket 88 that the artlcles,`such as the ice trays 2i, leave thecontainer` 84 on an upward incline. 'I'his construction prevents one tray from dripping on the next tray which is not desirable. Also the lip portion 85 of the container 8d is so designed that drippings from the trays as they leave the container 8d will be caught and redirected back into the container 8d. It will be understood that the chain conveying system may be run at such a speed that the article 2l will be conducted through the container Bd at a desired rate and will remain in said container for a suiiicient length of time to be coated suitably. If desired, the sprockets may be so positioned relative to one another` that a greater path of travel through the container 8f3 or a lesser one is elected. Also the length of travel of the articles 27 after they leave the container may be increased if it is desirable to provide a greater a pair of linger-like portions one of which is utidraining time than is shown for the devices in the drawings.

The modification of the present apparatus shown in Fig. 15 is similar to that shown in Fig. i4 except that the automatic dipping mechanism is separate from the remaining parts of the apparatus and, if desired, may be rendered portable and moved into position when it is desired to be used. Accordingly, the chain of the principal part of the apparatus shown at 5K0 goes about the sprocket 50a and thence through the tunnel 2d in the manner described hereinbefore and as shown in Fig. 1. There is provided a separate chain si and an additional sprocket t2 so that the chain 9i forms a separate continuous chain system running about the ysprocket a2 to the sprocket 8, thence to the sprockets Si, da, E@ and 9d. It will be understood that there is a similar chain on the other side of the device and that these chains are connected by spring bars in the manner described herelnbefore. On these spring bars the articles such as the ice trays @i are hung by a particular type of hook @3.

lized to hold the hook onto the spring bar and the other of whichxtends in the direction of air tunnel 2d. Accordingly,l when the pans 2? have been carried through the container all and coated, they are automatically transferred from a spring bar on the chain Si to one on the chain 5@ ofthe principal part of the apparatus, in the manner clearly shown in Fig. i5. 0f course it will be understood that the chain @t is driven by a suitable means (not shown) and that the speed of the chain 49i is synchronized with the `speed of the chain 5d so that the pans or other articles will be transferred automatically from the chain 9i to the chain 5t and thence conveyed through the remaining parts of the apparatus.

We claim: Apparatus for air drying and baking a protec= "tive coating for metallic articles 'subject to corr@ sion, which comprises a relatively elongated air conducting drying tunnel, a plurality of memrs arranged on a shaft extending across said tunnel for removing excessive coating material from said articles, each of said members being shaped to project into the tunnel for contacting said articles and being movable on said shaft on such contact so that the articles depress the members, an air conducting drying chamber communicat ing with said tunnel, a baking chamber commu-- nicating with said drying chamber, a furnace for producing a flow of heated air, a V.duct for directim said heated air into 'said mi chamber, air. blowing means for-forcing said air through said baking chamber into said drying n. 1t.- and into said tunnel, and a. continuous conveyor for conducting the articles through said tunnel through said air-drying chamber and thence through said .iwf chamber, whereby a coating on said arti es is air drim and `thereafter baked.

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