US1698700A - Tunnel kiln - Google Patents

Description

Jan. 8, l1929. 1,698,700 I G. W. BOOTH r TUNNEL KILN Filed March 28, 1927 2 Sheets-Sheet 1 lxlln LD tj! f1 Si m1500270 -il MMUnHUu J l@ /T ||w|1i|mwr|n IHM IHN --1 1---. -m VMM IMUHHWIIIH wl .M HH HH .MH ml@ -i l.. Huw JIM .,Hl hill MII... ....IIVMILIILII-. Tl l1 1| Ln- ----l ---1- JEL. --J\ Mm,

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YuNrrEo s'rAlrEs PATENT A OFFICE.

GEORGE w.y BOOTH, or NEW TORONTO, ONTARIO, OANADA.

TUNNEL KILN.

lAvmilication led March 28, 1927. Serial No. 179,074.

This invention relates to tunnel kilns for clay products of the type shown and described in my prior United States Patent 1,585,013, dated the 18th day of May; 1925, in which the drying ofthe ware is eifected in a chamberor f chambers extending lengthwise of the kiln. y

By such an arrangement a considerable saving vof otherwise waste heat is effected.

at the top 'My present object is to devise an improved construction whereby still greater economies may be effected and whereby more perfect control may be had of the successive operations of drying, pre-heating, ringandcooling.

' as described, or shifted in the tunnel towards or away from the cooling or the pre-heating zone. A further important feature is the arrangement whereby perfect control of the drying air at different parts of the length of thedrying chamber is obtained-and the moisture content of the ware thereby abstracted at suchva rate that warping and checking of the Ware is avoided. Further novel features of the construction are hereinafter described and illustrated in the accompanying drawings in which Fig. 1 is a plan of a kiln constructed in accordance with my invention;

Fig. 2 a side elevation of the same;

Fig. 3 a vertical section on the line 3--3 vin Fig. 1;

Fig 4 a longitudinal section on the line 1 4 .in Fig. l;

Fig; 5 a horizontal section of the kiln; and

Figs. 6 to 14 are transverse sections on the lines 6 6, 7 7, 8 8, 9 9, 1o 1o, n n, 12-12, 13-13 and 14-14 in Fig. 5.

In the drawings like numerals of reference indica-te corresponding parts in thedifferent figures.

1 is the tunnel of the kiln which, as usual7 comprises pre-heating, firing and cooling Zones. Thepre-heating zone extends from A to P (see Fig, 5), the firing zone from B to C. and the cooling zone from C to D. On top of the tunnelof the kiln is arranged the drying v.chamber 2 extending substantially from end to endyofthe tunnel. Both the tunnel 1 and the drying chamber 2 will be arranged as usual for the passage of trucks carrying the ware to, be tired.

In the drawings I have shown two dryingv chambers side by side, as this makes va convenient arrangement.V It will be understood .of course, that one only may be employed without departing from the spirit of my invention. l

Air heating and drying system.

of the kiln is formed an air supply conduit 3 to whichair may be supplied by means of a fanfl. This conduit` extends transversely of the kiln and communicates at opposite ends l 7o Adjacent the outer end of the cooling zone,

with air passages 5 formed in the vwall of the kiln at each side of the coolingzone. These passages extend from one end to the other of the cooling zone whereby there is a transfer of heat from the interior of the cool- Extending under the bottom of the kilnl Ving zone to the, air in the passages 5. To faare one or more longitudinal air passages 8, I

which extend past the firing `zone of the kiln andcommunicate with `a transverse air supply conduit 9 connected with the discharge outlet of a pressure fan 9a. The passages 8 communicate with a plurality Of'vertical' flues 10 extendingup` at both sides ofthe inner'wall of the pre-heating zone of the kiln. These iiues are separated byv meansV of theirvmetalwfalls 11 from the productsof combustion flues hereinafter referred to.

Each flue 10 is provided with van .upper and lower Opening 12, which openings are formed in the inner wall of thepre-heating Zone foradmitting air from the'flues 10 into the interior of the tunnel. Anydesired numberof these flues or openings may be closed mf y by suitable plugs (not shown) at any time to meet the needs of the case according to the qualities of the ware to be fired.

From the constructions described it follows that air under pressure may be introduced into the cooling Zone, or the pre-heating zone, or'both, by either fan 4: or 91 so that the products of combustion in the firing Zone may ybe held therein or allowed to travel somewhat towards either end of the kiln as maybe required.` It further follows that heatedv air is provided'to pre-heat the ware' passing throughthe pre-heating Zone of thel kiln and to assist'in the oxidation of the ware therein. Hereinafter it will appear how the vhot products kof combustion are utilized to heat the walls of the pre-heating zone, and

also to assist in heating the air passing through the tlues 10.

The air which passes through the lues 8 under the tunnel serves to cool the space bee nea-th the trucks passing through the Zones of the kiln. The air heated in the air passages extending along the sides of the cooling vzone of the kiln is utilized in drying thel ware passing throughkthe gdryingchambers y by means of the following constructions. At

eachs'ide of the kiln the' air passage 5 communicates with a vertical passage 13, which communicates at its lower end with one of the ai'rj passages VS and, at its upper end, with a longitundinal air distributing passage 14 which extends substantially from end to end iof the kiln. Damper's are provided atieachV end of each :vertical passage 13.V At 'each side, above the corresponding air distributing passage 14, is located an air passage 15 transversely divided into sections, each section communicating by means `of a damper controlled opening 16 with the air distributing passage 14. l farm dry air may thus be in troduced into each section according to cir-V cumstances. Each vsection communicates with the interior of the adjacent drying chamber by means of a longitudinal seriesl of openings 17 These openings,'it will be noted, are arranged along the top of the outer side wall of the drying chamber; Ceni trally of the kiln at or'about the level vof the lower part-s of the drying chambers I pro vide moist air flues 18. -Vhile one Hue might serve jI prefer to employ two as conditions 'in the two drying chambers may not be exact-ly the same. V'Ihe lower part of each drying chamberv communicates with one of the moist air flues by means of a longitudinal se# ries of openings 19. The moist air tlues are preferably divided into sections like `the air passages 15,V and each section communicates by means of a damper controlled opening v20 with the .draw-,off passage 21, which extends longitudinall of the kilnand adjacent the inlet end of t e drying chamber is provided with a suction fan 22 whereby the moisture laden air may be drawn o.

From the constructions described it follows that perfect control may be obtained of the admission of drying airand the drawing-off of moist air at dilferent points along the length of the drying chambers so that the rate of drying at dierent parts of the drying lchamber may be accurately controlled to prevent warping and checking of the ware. While manually controlled dampers might be employed, I prefer-toV employ automatic l temperature and humidity controllers, such as are well knownV in the art, andv which are illustrated diagr-ammatically. in the drawings.

The #ring sli/stem 'and utilization of the 'waste heat 0f the products of combustion.

While any Vfurnaces of known type may f be employed, I prefer to employ the furnaces illustrated, which are preferably of different types at different point-s in the length of the firing zone to enablethe tiring to be carried as best suits the-requirementsof the ware to be fired. Four types of furnace are illustrated, which are bestseen in Figs. 9, 10, 11 and 12 'of they drawings. Y. y

The first furnace I in the series illustrated Y in Fig. 12 is ofv ordinary type, and is preferably provided with a draft damper 23 auto= matically controlled by an automatic temperature controller of known type. This fur- `nace communicates directly with the interior of the kiln through an opening 24. At each side of the tunnel I form a flue 25 for thel products of combustion communicating with the interior of-the'kiln lby means of openings 26.v The products of combustion entering the tunnel Athrough the openings 24; may thus be drawn off through the flues 25 afterv trayelling a greater or less distance through the tunnel and around the ware being fired. Preferably the series of openings26 is extended substantiall'y the full llength ofthe pre-heating and firing rones of the kiln, as

some wares are not injured by early contact f At this end the flues communicate with down'- i wardly extending and transverse iiues 29 communicating with a transverse flue 30, with which communicates the suction fan 31 by .means of `which the produ-cts of combustion may .be drawn off. Under some conditions the `moist air from the draw-0Ev passage 21 may be allowed to pass ofi' with the products of combustion. I therefore provide each draw-cti passage with a damper controlled communication 32 with the transverse passage 27. 1t will be' noted that the hot products of combustion are utilized to heat the air passing through the flues l0, which air lissupplied through either thesair supply conduit 3,'orthe air supply conduit'9, or both.4

The second furnace II communicates with the interior of the tunnel through the openings 33 over the Hue 25.

The furnace HI communicates with the interior of the kiln through the-openings 34k,u

passage 34a and openings 34h, while furnace numberIV communicates with the interior of the tunnel through the openings 35. Any one or any combination of the furnaces may be used as desired for different classes of ware.

With the furnaces arranged as described hotproducts of combustion may be circulated in any desired manner through the ware to be fired.

All the furnaces areipreferably provided with automatic damper controllers similar to that of furnace No.` l, and generally speaking any of the openings or passages of the kiln may be provided-with dampers, though not hereinbefore set forth. l Y

It is obvious that theV arrangement described not only gives me perfect vcontrol of the drying, pre-heating, firing, and cooling of the ware but results in economy in operation as otherwise waste heat is utilized to the greatest possible extent and perfect control the drying chamber at dierent points inits length; dampers controlling the communi-L cations between the distributing passage and the sections of the sectional passage; and means for drawing air through the said passages, chamber and flue.

2. A kiln constructed as set toi-th Vin claim 1 in which the moist air flue is formed in separated sections and a` draw off passage. is provided in communication with each sectionv by means of damper controlled openings. A 3. The combination of a tunnel kiln; a separate drying chamber; an air passage formed in a wall of the chamber' communicating with the interior of the chamber at different points in its length; a sectional moist air fine' extending longitudinally of the kiln,

series of openings; a vdraw-off passage coin-- municating with eachsection of the moist air flue; dampers controlling the communications between the draw-oftz passage and thesections of the moist air flue; and means for drawing air through the said passages, chaniber and flue. l

4. The combination of a tunnel kiln; a sep`V arate drying chamber; a distributing air passageformed in the wall of the chamber extending longitudinally thereof; an air passage arranged adjacent the distributing passage divided into sections, each section communicating with the distributing passage and with the interior of the drying chamber; a sectional moist air flue extending longitudinally of the kiln, eachrsection communicating with the interior of the drying chamber; a draw-olf passage communicating with 4each section of the moist airfiue; dampers controlling they communications between the draw-off passage and lthe sections of the moist air fine; and means for drawing air through the said passages, chamber and flue.

5. rlhe combination of a tunnel kiln; a separate drying chamber arranged at the top of'` the kkiln whereby the chamberl will be heated by conduction from the kiln; an air passage formed longitudinally in a wall of the chamber and adjacent the kiln, the passage having a. series of openingscommunicating with the interior of the chamber; a moist air iue extending longitudinally of the kilnk communicating with the interior of the chamber at different points in its length means for drawing air through the said passage, `chamber Vand flue; a furnace; passagesffor the products of combustion including a Hue in the'wall of the chamber paralleling the aforesaid air passage; and means for drawing the products of combustion through said passages and flue A from the kiln. s v.

` 6. ri'Che Vcoml'iination of a tunnel. kiln; a separate drying chamber arranged at they top ofthe kiln whereby the chamber will be heat-Y ed by conduction from the kiln; an air passage formed longitudinally in a wall of the chamber and adjacent the kiln; the passage having a series ofopenings communicating with the interior of the chamber; a moist air flue extending longitudinally lof the kiln communicating withwthe interior of t-he cham: ber at different points in its length; means for drawing..airthrough the said passage, chamber and flue.; a furnace; passages forthe products of combustion including alflue in `the wall of the chamber parallelinff the aforesaid air passage; meansjffor drawing the products of combustion through said passages and'flue from the kiln; and a damper products of combustion whereby the moist air may be carried oli with the products. oi'

. combustion when desired.

7. A tunnel `kiln comprising a pre-heating, a liring and a cooling zone 1n combination with :an air heating passageformed in the wall of the cooling zone of the furnace; an air supply conduit communicating with the air heating passage and the interior of the cooling zone oi' the kiln; means for con-trolling the proportion of air passing to each; aV

drying chamber; and means for leadingthe heated air into said drying chamber.'

8. A tunnel kiln comprising a pre-heating,

' heating passage and the interior of the cool- CAB ing zone of the kiln; .means for controlling the proportion of'airpassing to each; a dryingl chamber; means yfor leading the heated air into saiddrying chamber; and a passage under the kiln communicating with the air conduit aforesaid -and with the interior of .the tunnel at the pre-heating zone. j

9. A tunnel kiln comprising a pre-heating, l

a tiring and a cooling zone in combination with an air heating passage formed Vin the wall of the cooling Zone of the furnace; an air supply conduit communicating with the air heating` passage and the interior of the cooling zone of the kiln; means for controlling the proportion of air passing to each.; a drying chamber; means for leading the heated air into said drying chamber; a passage under the kiln communicating with the air conduit aforesaid and with the interior of the tunnel at the pre-heating Zone; a flue through which the products of combustion from the firing zone are passed and which vextends along theY wall of the pre-heating zone; and means for effecting an exchange of heat between the said liuc and the air from the last mentioned passage as it passes into the pre-heating Zone of the kiln.

10. A tunnel kiln comprising a pre-heating; a firing and a cooling zone in combination with a passage extending throughout the greater part of the length or the three zones; an air supply conduit communieating with said passage and the interior of the cooling zone of the iurnace, the passage also communicating with the interior of the pre-heating-Zone of the kiln; and an air supply conduit communicating with said passage adj acent the pre-heating zone end of the same.

11. A tunnel kiln comprising a pre-heating, a tiring and a cooling' zone in combination with an air vheating passage formed in the wall of the cooling Zone of the furnace; a drying chamber; an air distributing passage communicating with the Vair heating passage adjacent the inner end of the cooling zone; means for leading air from the distributing passage to and through the dryingy chamber; and an 'air supply conduit commuV nicatmg with the air heatingpassage and the interior of the cooling zone ofthe kiln adja' cent its outlet end. j

12. A tunnel kiln comprising a pre-heating, a firing and a cooling zone in combination with a flue for the products of combustion extending along the wall of the pre-heating zone; a vertical flue extending up the side of and communicating with the pre-heating zone of the kiln and passing through the products of combustion flue; and an air supply conduit communicating with the Ver'ti` cal flue.

13. A tunnel kiln comprising a pre-heating, a tiring and a. cooling zone in combination with a flue for the products of combustion extending along the wall oi the pre-heatL ing Zone; Vert-ical flues extending up the side ofand communicating with the bottom and' top of the pre-heating Zone of the kiln, the said flues having metal walls separating them from the products of combustion iiue; and an air supply conduitcommunica'ting with the Vertical flues. j

' -14. Atunnel kiln comprisingapre-heating; a tiring and a cooling Zone in combination with a flue for the products of combustion located in the wall of the kilnand extending along both the liring and pre-heating Zones;

a furnace communicating with the interior of the tunnel at the firing zone adj acent theco'oling zone; openings' being formed from the interior of the tunnel into the iuerat dilerent points vin the length oi the vfiring zone ;l means for drawing gases from said liuc; and means for introducing air under pressure into the interior of the tunnel at the preeheating zone.

l5. A tunnel kiln comprising a pre-heating; a firing and a cooling zone in combination with aflue for the products of combustion` located in the wall of the kiln and extending along both the firing and preheating zones; a furnace communicating with the interior of the tunnel adjacent the cooling zone, openings being ormed from the interior of the tunnel into the flue at different points in the length of the liring zone and the pre-heating Zone; means for drawing gases from saidflue; and means forfintroducing Vair under pressure into the interior of pre-heating Zone.

16. A tunnel kiln comprising a pre-heating; a iiring and a cooling Zone in combination with a flue for the products of combustion the tunnel at the ucts of combustion from the drying chamber Hue; means for pre-heating air; a passage for air extending along the wall of the drying chamber communicating with the interior of the chamber; a moist air Hue alsocommunicating with the interior of the chamber; means for drawing air from the moist air Hue; and a damper controlled communication between the moist air Hue andthe drying chamber Hue for products of combustion.

17. A tunnel kiln comprising a pre-heating, a firing and a cooling zone in combination with an air passage along the bottom of the tunnel extending from the cooling zone to the pre-heating Zone Vand communicating with the interior of the tunnel at the pre-heating zone and the cooling zone; an air supply con-V duit connected with the passage; and means for controllingl the How therefrom to the said zones. Y

18. A tunnel kiln comprising a pre-heating, a firing and a cooling zone in combination with an air passage along the bottom of the tunnel extending from the cooling zone to the pre-heating zone and communicating with the interior of the tunnel both at the preheating zone and-the cooling zone; air supply conduits connected with the passage adjacent opposite ends and means for controlling the How therefrom to the said Zones.

19. A tunnel kiln comprising a pre-heating; a Hring and a cooling zone in combination with a vHue for the products of combustion located in the wall of the kiln and extending along both the firing and pre-heating Zones; a furnace communicating with the interior of the tunnel at the firing zone adjacent the cooling zone, openings being formed from the interior of the tunnel into the Hue at .different points in the length of the Hring zone; means for drawing gases from said Hue; and-means -for introducing air under pressure into the Y interior of the tunnel at the cooling zone. Y

20. A tunnel kiln comprising a pre-heating, a Hring and a cooling Zone in combination with a `Hue for the products of combustion locatedin the .wall of the kiln andextending the pre-heating zone; and means for drawing gases from said Hue at a point remote from the furnace.

21. A tunnel kiln comprisinga pre-heating, a. Hring and a cooling zone in combination with a Hue for thel products of combustion located in the wall of the kiln and extending along both the Hring and pre-heatingfzones;

a furnace communicating withthe interior of the tunnel adjacent the cooling zone, open ings being formed from the interior of the tunnel into the Hue at diHerent points in the length of the firing zone and the pre-heating zone; means for drawing gases from said Hue; and means for introducing air under pressure into the interior of the'tunnel at the preheating Zone and atv the ycooling zone.

22. A tunnel kiln comprising a pre-heating, a firing and a cooling zone in combination with a passage extending throughout the greater' part of the length of the three zones and communicating with the interior of both the cooling and pre-heating Zones; means for supplying air under pressure to said passage; and means for controlling the air passing from the passage into said zones to vary the relative proportion of air Howing to each.

Signed at Toronto this 3rd day of March, 192 l lesoneri w. Boorii.

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