US1340633A - Kiln - Google Patents

Description

J. N. SILVA.

KILN.

APPLICATION FILED FEB. 28. 1919 Patented May 18,1920.

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KILN.

APPLICATION FILED FEB. 28, 1919- 1 140,633. Patented May 18, 1920.

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J. N. SILVA.

KILN.

APPLICATION FILED FEB. 28. 1919.

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mum II I WITN "S JUAN N. SILVA, OF DOVER, OHIO.

KILN.

Specification of Letters Patent.

Patented May 18, 1920.

Application filed. February 28, 1919. Serial No. 279,842.

To all whom it may concern:

Be it known that I, JUAN N. SILVA, a citizen of Mexico, residing at Dover, in the county of Tuscarawas and State of Ohio, have invented certain new and useful Improvements in Kilns, of which the following is a specification.

This invention relates to kilns, andmore especially it is an improvement on my former Patent #1192946 dated August 1, 1916.

The improvement consists primarily in the adaption of a grateless furnace or a forced draft furnace to the burning of slack coal, seas to reduce expense. It consists also in the simplification of the structure described in my former patent in that I am permitted to use but a single connecting flue between contiguous kilns. and one damper therein instead of five as hitherto. The invention also comprises the feature of turning the products of combustion (or most of them) from the exhaust tunnel, and conducting them again through the feed tunnel and the kilns for use the second time. This I find to be possible under certain conditions, especially if some fresh air is mixed with the gases. The latter in any event are quite warm, and the kilns are not chilled by the admission of cold fresh air alone. The invention also comprises certain details in construction, all of which will be more fully described and claimed, and are shown in the drawings wherein-- Figure 1 is a diagrammatic plan view showing a battery of eight kilns connected up with the feed and exhaust tunnels and connected with each other by a single pipe between their several manifolds, parts of the diagram being in section, for a purpose yet to appear.

Fig. 2 is a horizontal section through a pair of adjacent kilns taken on the level of their furnaces. I i

Fig. is a vertical section through three adjacent kilns and their furnaces, showing the means of connecting the various chambers and'the kilns themselves.

Figs. 4 and 5 are enlarged vertical sections respectively through a grateless furnace and a forced draft furnace.

Fig. 6 is a perspective detail, partly broken away and in section, of one of the valves in the manifold.

Fig. 7 is a horizontal section on the line 7-7 of Fig. 5.

Fig. 8 is a longitudinal sectional detail of one of the dampers referred to below, and

Fig. 9 is a cross section thereof.

The kilns throughout the system or battery are by preference disposed as shown in Fig. 1 if they are built at the time this invention is set up, but it is quite possible to apply my system of heating to a series of kilns already erected, and therefore their position may or may not be that herein illustrated. Each'kiln by preference has a circular wall with adome shaped top or crown wall 2, the circular wall being thickened near its lower portion as at 3 and provided at numerous points with fire boxes 4:, each with its bag wall 8. Such is the preferred construction whether the furnace be of the grateless type shown in Fig' 4: or the forced draft type shown in Fig. 5, but my system will work equally well with either type. In the former, a tile 5 at the outer side of the thick wall 3 separates upper and lower doors 6 and 7, whereas in the forced draft of furnace the tile 5 is at the bottom and there is a single opening covered by a door 7 which is hinged upon the wire 6. A substantially vertical fine 9 leads from the fire box 4 upward outside the bag wall into the interior of the kiln structure, and the surrounding wall of the latter is pierced at one point with a doorway 10 whereby entrance to the kiln is permitted.

The floor 11 of each kiln has openings 12 communicating with flues 13 beneath, and these in turn communicate through a central well. 14 with a lower or connecting flue 15' which extends throughout the series of kilns and communicates with the stack or chimney 16 in a manner yet to be described, this connecting flue being provided with a damper 17 between each two kilns. This damper as perhaps best seen in Fig. 8, I prefer to make in the form of a plate sliding vertically within guides 15 at the sides of the flue 15, so that when the plate is dropped the flue is closed almost air tight. From the plate a rod 17 rises through a suitable opening to a handle 1'7 which lies at the surface of the ground, and therefore the operator can raise this plate to open the flue and fasten it in suspended condition in any approved manner, as perhaps, by turning the rod 17 downward on the surface of the earth.

In connection with the series of kilns I employ a main or exhaust air tunnel 22 and a main air feed tunnel Air is forced through the feed tunnel 23 by a blast fan or blower 24, and from said tunnel it flows into a circular manifold flue 25 whereof one surrounds each kiln and has its end portions 26 and 27 respectively connected with the feed and exhaust tunnels as seen in Fig. 2. Each of said ends is provided with a damper preferably in the form of gate valve 28 as best seen in Fig. 6. This gate valve is shown as hinged at its bottom as shown at a and swinging open within a pit b between spaced sections of the flue end 26. A chain 0 leads from the gate to and is wound upon a shaft d mounted at its lowerend in a step bearing 6 in the bottom of the pipe 26 and passing at its upper end through a suitable bearing f in the top of the pipe, the upper extremity of the shaft having a hand wheel or handle g. A ratchet 71 fast on the shaft may be engaged by a pawl i mounted on a plate j overlying the bearing f, and when the gate valve has been drawn sufiiciently near to a closed position, the actuating mechanism may be latched by engaging this pawl with the ratchet wheel. Only the handle of the valves appear in Figs. 1 and 2 and l numher the handles 28 and 29 to difierentiate between the valves within the ends 26 and 27 respectively. The former is obviously the inlet valve, permitting air to flow into the manifold 25, and the valve 2.) is obviously the outlet to retard or check the flow of fluid from said manifold to the exhaust tunnel 22. The connection between the manifold 25 and each furnace is by means of branch pipe 30 containing a damper 18 beyond which it communicates with an air chamber 19 under the furnace. The damper 18 is best shown in Figs. 14 and 5 as being a rotary damper whose stem carries a handle 18 which handle may be shaped like a wheel if desired. I consider it desirable, however, that the handle shall stand within a pit 18 dug into the ground and normally closed by a cover 18 hinged at 18 so that the handle will be entirely covered under normal conditions. This prevents the operator from striking his foot against it, which might result in his injury or might result in a changing of the position of the damper undesirably, and yet whenever the damper is to be set, the cover is raised and access is immediately gained to the handle in a manner which will be clear. I might say at this point that long experience has taught me to provide dampers of the types suggested herein for various reasons which need not be elaborated in the present specification. However, I do not wish to confine myself strictly to the details thereof.

The chamber 19 is separated from the furnace proper by means of a perforated plate 20 having within it a removable perforated disk 21. The perforations are sufficiently line to enable the furnace to use slack coal when under full fire, thereby greatly decreasing the cost of fuel; but when the fire is drawn and the kiln is drying, the disk is removed from the plate to permit free circulation of air upward or downward through the flue 9 as described below. The use of the doors 6, 7 need not be amplified and the dampers 18 may be controlled by handles as shown or otherwise.

The exhaust tunnel 22 leads into the easing ofan exhaust fan carried by a drier, and another outlet controlled by a damper 32 leading into the stack 16. The inlet to the blower 2 1 leading to the feed tunnel 23 may be also twofold. One branch connects with the cold air and is controlled by a damper 24' while the other branch connects -with the stack and is controlled by a damper 16. Thus it is possible to close the latter and open the damper 24:, and the blower 24- will feed cold air along the tunnel 23. Meanwhile the exhaust fan 21 is delivering products of combustion entirely into the stack, entirely'to the drier, or partly to both according as the dampers 31 and are set. On the other hand, assuming that most or all of the exhaust is delivered into the stack through the open dampers 32 it is impossible to admit to the feed tunnel some cold air and some exhaust, or all of the exhaust, according as the dampers 16 and 24: are set. The utility of the detail. will appear below.

The uses and advantages of a system con structed in accordance with my invention will now be apparent. Attention is invited to the fact, however, that the furnaces may be of any type which will operate successfully in connection with the kilns, and the latter may be of type and size capable of being united in a system as described. Flues or tunnels already built may to a large extent be utilized. As above stated, the kilns need not stand as shown in diagram in Fig. 1. The two main fines or tunnels 22 and 23 will. extend throughout the length of the series of kilns, and a manifold 25 will surround each kiln with its ends 26 and 27 connected with said tunnels. Particularly the connecting flue 15 will communicate through well 14 with the center of the bottom of every kiln, and by use of the dampers 17 the operation will be as follows: Fires will be built in the furnace of one kiln, and fresh air admitted thereto through the manifold and through the dampers 18 and perforated plates 20. The products of combustion will flow up the fines 9 over the bag walls 8, under the crown and thence downward to the central portion of the kiln which rapidly becomes warm during this preheating operation. The products of combastion pass through the openings 12 in the floor ll, along the several fines 13, down ward through the oll 14, and into the connecting fine l5; and therein parts thereof are conducted to the next contiguous kiln by leaving open the damper 17 between and the remaining parts of combustion are conveyed to the third kiln by leaving open the next damper 1'1". in the second and third kilns the products of combustion obviously rise through the openings in the floors, and they pass upward to the crowns and thence downward in the fines 9 and the tire boxes 4 which in these kilns are empty because no fires need be built therein. In other words, the flow is in directly the opposite direction, but the kilns are dried out and pro-heated by utilizin the products of combustion from the "st kiln in whose furnaces fires have been built. @bviously the kiln next the one which is fired up will be heated more rapidly and the next a little less rapidly. Then the fires are kindled in the fire boxes of the kiln, the products of combustion will pass upwardly through lines 9 into the dome 2 of the kiln. At this time it should be understood that the blower 24 communicating with the air teed tunnel 23 is in operation, as is the exhaust fan 31 which of course is therefore drawing air from the exhaust 22. lit only the kilns of one series are in use, the valves 28 and. 29 of the remaining series are closed. As air passes through the tunnel 23, obviously it will be passed about within the manifold lines 25 and "ill then be drawn out\ ."ardly to be ted through the exhaust tunnel This is due to the fact that the suction within tunnel. 22 may be so great as to prevent the feed of air or the manifolds from passing up into the fire boxes of the several ail .s, particularly beyond the first kiln, for at the first kiln the valve 28 may be opened and the valve 29 closed so that the air pass-- ing into the manifold will pass up through the fire boxes to cause the fires therein to burn. vigorously. Therefore, the products oi combustion which have arisen into the Idome as above specified will pass downwardly through the bricks carried within the kiln and through the floor 11 of this first kiln down through the fine l3 and the cent al well i l and into the connecting flue 15. At this time, the dampers 17 between the first and second and the second and third kilns are open although beyond the third kiln the next damper should be closed. The suction within the manifolds 25 about the second an d third kilns owing to the fact that the gate valve is opened will be such as to cause air to be sucked from the kilns down through the fines 9 and into the manifolds 25 to be exhausted into and through the eX- haust tunnel 22. Thus the suction within the second and third kilns will produce similar suction within the fines 13 thereof as well as their central wells ll and thus this suction will be present in the connecting line 15. Accordingly, the products of combustion which pass down into the connecting fine 15 from the first kiln will pass along the connecting flue. Upon these products of combustion arriving below the second kiln obviously the suction into the kiln from the lower portion thereof will cause part of the products of combustion to rise into this sec- 0nd kiln from the bottom thereof. The remaining products of combustion continue along the connecting fine l5 and these re- .u'iaining parts will pass up into the third flue, owing to the suction therein, as they cannot pass further along the connecting fine 15, since the damper 1'? beyond the third kiln is closed. As these products of combustion rise from the connecting fine 15 they will pass through the floors 11.01 the second and third kilns up through the contents of these kilns and then will pass around down through the fines 9 and fire boxes 4; into the manifold flues 25 and encir cling the second and third kilns. As the suc tion within these manifold lines 25 is very strong, these products of combustion will then be d awn into the exhaust tunnel 22 and finally be exhausted. It will therefore be apparent that although the products of combustion are by far the hottest within the first kiln, they will pass with decreasing temperature to the second kiln and even with less temperature to the third kiln. However, the heat rising from the bottom of the second and third kiln will gradually dry out the lower parts of the kilns and the contents thereof and will begin to heat the same very gradually and evenly. After the first kiln has completed its operation, fires will be started in the fire boxes of the second kiln and then the damper beyond the third kiln may be opened and the operation will continue to the second, third and fourth kilns as specified for the first, second and third kilns. However, the advanced kilns which have been preheated as specified will acconi ilish their functions very easily for as the fire is burning within the fire boxes for instance of the second kiln, the heat and products of combustion will very quickly dry out the upper portion of the kiln and then bake the contents thereof in the usual manner.

Where the kilns are preheated from the bottom before the down draft is started a more uniform burn is secured and the percentage of scrap is greatly reduced. The top of the were will not be overheated while the bottom remains soft, a common occurrence with down draft kilns. This feature applies particularly to the two extremes of building brick and silica brick; in the case of the former it is easy to overburn the top with a heat barely suflicing for the bottom, while with silica brick the high temperature necessary to get a good finishing heat at the bottom requires an unusually great amount of fuel and labor.

Of course, if it is only desired to use the first kiln for some particular purpose, the damper 17 between the first and second kiln will be closed while the rear damper 17 will be opened so that as the products of combustion arise in the kiln and then finally pass down into the connecting fine 15 they will be immediately withdrawn into the exhaust tunnel 22 at the point 33, although when the device is in operation for preheating kilns in advance of the first kiln, obviously the damper in the connecting flue 15 in the rear of the first kiln must be closed. Eventually the first kiln may be charged and may be put into full fire and at work, then a fire can be built in the second kiln and third and fourth dried as described above. Depending on the character of the work to be done and quantity being fired or dried, considerable latitude must be left to the operator as to the character of the fires, and the duration of the various steps. Also the detailed construction at the left of Fig. l is important as controlling the inlet and outlet from the tunnels. As stated above, clear air or air mixed with gases from the stack may be admitted, and the outlet is also susceptible of various uses.

The skillful operator will use products of combustion and gases over and over again as long as possible, and while they are warm they can be utilized for heating kilns which are yet to be fired. It is obvious that this control of the feed and exhaust may be brought about by connecting up the tunnels with the stack and with the drier (if one be employed) quite remote from the group of kilns, and that the exact character of the furnaces in the kilns is not important. Also it will be clear that manifolds can be ap plied to and connected with the'kilns, whatever the construction of the latter. T herefore, it is possible to set up my system in a plant whose kilns are already erected and whose stack is ready for use. Vhile I prefer to employ the gate valve shown in Fig.

6 at the points where the ends of the manifolds are to be controlled, this is not absolutely necessary.

The foregoing description and the drawings have reference to what may be considered the preferred, or approved form of my invention. It is to be understood that I may then make such changes in construction and arrangement and combination of parts, materials, dimensions, et cetera, as may prove expedient and fall within the scope of the appended claims.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is 1. The combination with a plurality of kilns, a feed tunnel and an exhaust tunnel extending past them all, a manifold connected at its ends with said tunnels respectively and with its body encircling each kiln and communicating with the interior thereof near itswall, and valves in the ends of each manifold; of a single flue common to the series of kilns and communicating with the centers thereof through their bottoms, connections between this flue and the exhaust tunnel, an exhaust fan in the exhaust tunnel, a branched outlet therefrom, one branch leading into a stack and provided with a damper, a blower in the feed tunnel, inlets thereto whereof one is from said stack, and dampers in said inlets.

2. The combination with a plurality of kilns, a feed tunnel and an exhaust tunnel extending past them all, a manifold connected at its ends with said tunnels respectively and with its body encircling each kiln and communicating with the interior thereof near its wall, and valves in each manifold; of a single flue common to the series of kilns and communicating with the centers thereof through their bottoms, connections between this flue and the exhaust tunnel, an exhaust fan in the exhaust tunnel, an outlet from said fan into the stack, a damper in said outlet, a blower in the feed tunnel, an air inlet to its casing controlled by a damper, and an inlet from the stack to its casing also controlled by a damper.

In testimony whereof I affix my signature in presence of two witnesses.

H. H. Hosrn'r'rnn, F. H. WALDRON.

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