US2932905A - Ceramic ware dryer and preheater and method - Google Patents

Description

April 19, 1960 w. L. HANLEY CERAMIC WARE DRYER AND PREHEATER AND METHOD Filed May 28, 1957 2 Sheets-Sheet 1 April 19, 1960 w. L. HANLEY CERAMIC WARE DRYER AND PREHEATER AND METHOD Filed May 28, 1957 2 Sheets-Sheet 2 INVENTOR.

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CERAMIC WARE DRYER AND PREHEATER AND METHOD William L. Hartley, Greenwich, Conn.

Application May 28, 1957, Serial No. 662,278

2 Claims. (Cl. 34-213) This invention comprises improvements in methods of drying and preheating green molded ceramic ware such as brick, tile and the like in preparation for its introduction into a kiln and in a dryer and preheater by means of which such methods may be practised.

One object of the invention is to provide an improved form of dryer and preheater mechanism for freshly molded green ceramic ware by means of which the required amount of moisture can be rapidly and efficiently removed from and the ware preheated with a minimum expenditure of power and heat energy.

Another object of the invention is to provide a novel form of apparatus for these purposes, constructed and arranged to effect efficient movement of the hot air used for drying and preheating purposes and the removal of the relatively cooler moisture laden air after it has performed its drying function.

Another object of the invention is to provide an apparatus of this kind in which the humidity in the dryer can be controlled to insure the correct drying cycle for such ware.

A more specific object of the invention is to provide a dryer and preheater construction arranged so that the motor driving mechanism for the fans which circulate thefdrying air is kept relatively cool and is made readily accessible for maintenance without interrupting the operation of the dryer.

Other and more detailed objects of the invention involving the structure will be apparent from the following description of the form thereof illustrated in the attached drawings.

Still another object of the invention is to provide novel methods of operating dryers and preheaters of this type to insure the maintenance of proper humidity conditions within the device to facilitate overall efiicient operation and the production of properly dried ware.

In the accompanying drawings,

Figure l is a typical vertical cross-sectional view of a dryer and preheater in accordance with this invention, taken for example, on the line 1-1 of Figure 2;

Figure 2 is a composite view of the dryer and preheater of Figure 1 showing the construction at different vertical levels, the lefthand portion of the view being a top plan view; and

Figure 3 is a front elevational view of the dryer and preheater. i

As is well known in the art of manufacturing of brick, tile and similar ceramic ware, such ware is first molded to shape in a relatively wet condition. It is then stacked on cars and placed in dryers where it is subjected to hot gases which dry the ware to the state where it is ready for introduction into the preheater section of a firing kiln. As is not unusual in this art, the hot gases used for drying the green ware are withdrawn from some other portion of the process such as for example from the firing section of the kiln.

It will be apparent as the disclosure proceeds that it Patented Apr. 19, 1960 lad is unimportant from what source the hot gases are obtained. However, in order to insure eincient use of as much as possible of the heat energy involved in the heating of ceramic ware, it has been found that the hot gases which are withdrawn from the firing section of the kiln, and in some cases from the preheater section, have suflicient available heat to make them useful in drying and preheating the green ware.

The device of this invention is constructed and arranged so that the ware can be heated to considerably higher temperatures than has heretofore been practised in the drying of green ware in preparation for its introduction into the preheater of the brick kiln. The parts are so arranged that the ware can be dried and brought rapidly to a considerably higher temperature so that upon introduction into the preheater of the kiln it can progress therethrough more rapidly, providing a general overall increase in output.

As illustrated in the drawings, the dryer and preheater includes a footing and foundation 10, made of any material suitable for the purpose, and commonly of brick. The peripherial outline of the foundation can vary, but as illustrated it is generally rectangular. Erected upon the foundation are side and end walls 12 and 98, all of which may be composed of brick or concrete work, and preferably, as illustrated for the side walls, be of the double wall construction to provide a dead air insulating space therebetween.

The roof of the structure can be in the form of a flat arch l4 and likewise constructed of suitable material such as a reinforced concrete slab. As is clearly illustrated in the various figures the end walls 98 of the housing are open at the center and at the ground level to form an open ended tunnel extending all the way through the housing. This tunnel is formed by a low ground level foundation in the form of a reinforced concrete slab Z2 and serves as a support for a pair of Walls 20-24 which define the space forming the tunnel. In other words, the end walls 98 are open in alignment with the tunnel S1 which thus results.

Extending transversely across between the side walls and below the fiat arch 14, are a series of reinforcing angle irons 16 which are interconnected with a series of vertical angle iron supports 18 to form an interior open framework upon which the internal parts of the structure are mounted, as will be explained below.

Mounted on the two central rows of vertical, angle irons 3.3 are the vertical walls which are provided with a series of pairs of aligned openings 42 which are preferably framed by reinforcing angles as shown. The outer walls 12 and the vertical walls 34 form a pair of parallel main ware treating tunnels. Extending between the walls 345 is a horizontal wall 49 having a series of large circular central openings as which are respectively aligned with each pair of openings 4-2. The horizontal Wall 4!) divides the central space between the walls 34 into a pair of longitudinally extending chambers .53 and S4, the former being above the latter.

Extending longitudinally through the chamber S4 is a baffie wall 43 which is constructed of a series of gen erally Ushaped angle irons embedded in a heat resistant reinforced covering which may be made of commercialiy available insulating cements. This generally V-shaped bafile Wall forms below it the tunnel S1, isolating that tunnel from the space 84 The battle wall 58 runs all fthe way from the front end to the back end of the housing extends to that source or to several sources.

At this point it may be noted that the chambers S3 and S4 are closed by the end walls 98 of the housing, with the exception that each end wall has an access door 100, as shown in Figures 1 and 3. The chambers S2 are provided at each end with doors, not shown, by means of V -which the cars C may be introduced thereinto and re- 'moved'therefrom. These cars ride on rails R, which are mounted at ground level at the bottom of the chambers S2. At this point it may be noted, as diagrammatically illustrated, that the freshly molded green ware is stacked on these cars, usually in the form of two laterally spaced stacks WS, to form free spaces around the top and the ing drive shaft 52 journaled in the bearings 50 and extending through an opening 58 in baiile wall 48. The

opening 58 is large enough to permit free flow of air around the shaft 52. Mounted on the upper end of the shaft 52 is a propeller assembly 56, which is positioned in the opening 46 of the wall 40. It will be noted that there is one of these propellers with its drive stationed at each of the openings 46, and hence each of a pair of associated openings 42. The number of such assemblies will vary, of course, with the length of the dryer and the structure is dimensioned so that when the dryer is full of cars there will be two cars with their stacked ware stationed laterally opposite each of the propellers 56.

Supported on the fiat arch 14 of the dryer are a series of conduits 64 and 68 laterally and longitudinally spaced along the dryer housing. The conduits 64 open into the spaces S2 at the top. Each of the conduits 64, 68 is provided with dampers 66 and 7 respectively. The conduits 64 and 68 connect respectively with longitudinally extending header ducts 60 and 62, which either extend to a common connection which in turn extends to the source of hot dry gases, or each of which individually The headers 60 and 62 provide the main hot gas supply conduits for the dryer. Distributed along the top of the housing so as to be individually vertically directly above the propellers 56, are a series of exhaust duct branches 76 which open directly into the space S3 which extends throughout the length of the dryer housing. Each of the branches 76 is provided with a damper '78 and all of them are connected with a main exhaust header 72. The exhaust header 72 is provided with a main stack 74 through which the relatively cool gases are discharged to the atmosphere after passing through the dryer.

The method of operating this dryer takes cognizance of the fact that the cars C with the green molded ware stacked thereon in lateral and longitudinally spaced stacks WS to form spaces between and around them are pushed in end to end relation into the housing from one end and removed from the housing at the other end, along the rails R. Assuming that the dryer has been in operation so that each of the drying tunnels S2 is completely occupied with cars C, it is apparent that the ware going in the entrance end will contain the most moisture, while the ware leaving the exit end will be dried and heated to the required degree. In the usual practice the cars are moved through the dryer and preheater intermittently, with periods of rest when the doors, not shown, in both ends of the tunnels S2 will be closed. Hot gases from any suitable source, including the firing zone of a brick kiln, as previously suggested, are supplied under pressure into the ducts 60 and 62. The hottest gases are supplied into the ends of these tunnels adjacent the exit end of the dryer and portions thereof are directed from the main duct 60 and 62 into the circulating path comprising the compartments S2, S3-, and S4, at the. sides, and at points distributed longitudinally along the housing from one end to the other, through the respective branch ducts 64 and 68.

Each of these ducts is provided with a damper, as illustrated at 66 and 70, so that controlled amounts ofthe hot gases can be discharged into the circulatory paths at points along their length, that is from one end of the housing to the other. These hot gases circulate within the housing, as shown by the arrows, so as to move downwardly, for example, from the branch 64 into the space S2, into contact with the sides and tops of the stacks WS. After picking up moisture from the stacks, this air passes through the large openings 42 into the space S4 and are impelled by the propellers 56 upwardly into the space S3, which extends throughout the length of the housing as do the spaces S2. Much of these gases then follow the arrows, as shown, back into the spaces S2. Thus it can be said that the blanket of hot gases is caused to circulate through the drying and heating tunnels S2 aided by the propellers 56..

Controlled portions of these circulating blankets are withdrawn through the branches 76 into the exhaust header 72 and from there by way of the stack 74 to the atmosphere. Each of the branch ducts 76 is provided with an adjustable damper 78 so that'the proportion of moisture laden relatively cooler gases withdrawn thereat can be controlled. It follows, therefore, that both the temperature and the moisture content of the gases circulating in the blankets around the drying tunnels can be adjusted by means of the dampers 66 and 78 in 76 and 68 to effect the drying and preheating of the green ware at the best rate and to the proper final moisture con- 7 tent for the ware.

Thus by these multiple controls it is possible to gradually extract the moisture from the greenest ware as it progresses from the entrance to the exit end of the housing, so that when a car C is pushed out of the exit end the ware stacks WS will be dried and heated to the proper extent which experience has demonstrated to be the best, and in addition the ware will be at a temperature suitable for immediate introduction into the preheating section of the main firing kiln.

An important feature of this invention is the provision of what might be called maintenance tunnel S1, extending from one end of the housing to the other, and of' a height to provide headroom for a maintenance man, giving him ready access to the motor drives and bearings for the propellers 56.

Another important feature of this arrangement results from the fact that the maintenance tunnel S1 is open at both ends and the rotating propellers 56 are permitted to draw fresh air from the tunnel S1 through the relatively large openings 58 .around the motor shafts 52, and of course, over the motors 54 and bearings 50. Thus, this equipment in addition to being readily available for the necessary maintenance, is kept relatively cool and substantially out of direct contact .with the hot gases circulating within the dryer. It will be understood, of course, that the roof or hood for the tunnel S1 extends through.- out the length of the dryer.

It will be noted by reference to the drawings that the driving mechanism for the fans 56 while generally aligned with the take-off branches 76 are mounted at the bottom of, in the region of, or at a level towards the bottom of the main tunnels S2. The baffle wall 48 with the enlarged opening 58 for the shafts 52, makes it possible for the fans 56 to drive cool air from the tunnel S1 over the driving equipment for the fans, keeping them below dangerous operating temperatures. In other words, this driving equipment instead of being in the path of the hot gases is completely out of that path and arranged to be included in the cooling air path in a very simple way and at the same time making the driving equipment readily available for maintenance.

In view of the above description it will be apparent to those skilled in the art that the subject matter of this invention is capable of considerable variation in its details of construction involving features which are not of prime importance to the novel subject matter herein disclosed. It is preferred, therefore, that the example illustrated and described herein not be considered in a limiting sense, and that the scope of protection afforded by this patent be determined by the claims.

What is claimed is:

1. A device of the type described comprising a housing having an interior wall structure to form two laterally spaced drying chambers and a central chamber lying therebetween, said central chamber being adjacent to and substantially longitudinally coextensive with said drying chambers, means for supplying hot gases into said drying dhambers at a number of points along the length thereof, means for withdrawing gases from said central chamber along a number of points distributed therealong, a baflie wall extending along said central chamber to form a maintenance tunnel, a further wall having fan openings extending along said central chamber above said baflie wall, the walls of said drying chambers having air passages opening into the space between said baflie wall and said further wall, said baflle wall and said further wall being horizontal, extending substantially across said central chamber and being supported from. the side walls thereof, and motor driven fans mounted in said fan openings having their power drive mounted in said maintenance tunnel and connected to respective fans by drive shafts extending through said bafile wall.

2. In the combination of claim 1, said balfie wall having air passages around said shafts passing therethrough.

References Cited in the file of this patent UNITED STATES PATENTS 553,723 Proctor Jan. 28, 1896 1,451,589 Schwartz et a1. Apr. 10, 1923 1,513,932 Rhoads Nov. 4, 1924 l,567,023 Larsson Dec. 22, 1925 1,840,523 Mueller Jan. 12, 1932 1,841,927 Allsop Jan. 19, 1932 2,085,634 Cobb June 29, 1937 2,758,388 Westerberg Aug. 14, 1956 FOREIGN PATENTS 521,005 Germany Mar. 18, 1931

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