CN1008553B

CN1008553B - S-shape crossling kiln

Info

Publication number: CN1008553B
Application number: CN 85108871
Authority: CN
Inventors: 龙怀安
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-12-05
Filing date: 1985-12-05
Publication date: 1990-06-27
Also published as: CN85108871A

Abstract

The present invention relates to a production device and a production method for tiles in building materials. The S-shaped crossing kiln of the present invention is provided with two outer kiln pipes and one inner kiln pipe; the three kiln pipes are connected into a double ring shape which causes the head and the tail of the S shape to be connected to the bending part of the double ring shape. A roasting flue net, a humidity expelling flue net, a cooling zone hot air duct and a wet basis dewatering plate are arranged in the kiln. The operation method is a circulating roasting method which is characterized in that one cycle period comprises S-shaped operation and crossing operation without an airing field or a drying chamber. Blank pieces are baked by residual heat, the roasting time can be shortened, the energy consumption can be reduced, the quality can be improved, the productivity can be improved, and the cost can be reduced.

Description

S-shape crossling kiln

The present invention relates to the continous way kiln of a kind of production unit of material of construction, particularly firing brick-and tile.

Large continuous brick and tile kiln originally mainly contains tunnel furnace and annular kiln.Tunnel furnace is that the kiln body is linear tunnel like kiln, in tunnel furnace, is provided with track, moves with the kiln car on the top car ejection track, is provided with fuel port at kiln body top and side.During the kiln running, preheating zone, roasting band, insulation belt and cooling zone in the kiln maintain static, and the calcining matter that is placed on the kiln car moves along the tunnel with kiln car.This kiln, though the mechanization degree height is realized automatization easily, manufacturing cost height, maintenance cost height, poor sealing performance, energy consumption height.

Annular kiln in the large continuous brick and tile kiln originally, it is 1 the oval ring of the continous way tunnel that is formed by connecting by several firing chambers, vertical diad portion at annulus has 1 to be the main flue of roasting flue, the branch flue that all there is wicket each firing chamber and communicates with main flue, the part of above-mentioned branch flue is set at below the kiln bottom surface, in flue, be provided with air lock, be provided with the fuel port of fueling that adds in a row at the kiln top.During the kiln running, the calcining matter of being piled up in the firing chamber maintains static, and the roasting that fuel drops into corresponding fuel port is in turn moved in dependence, makes preheating zone, roasting band.Each band such as insulation belt and cooling zone moves forward continuously with the progress of roasting.Annular kiln is simple in structure, and kiln laid down cost is lower, but wet basis can not be directly into the kiln roasting, therefore, needs roomy wet basis to dry in the air or drying facility such as kiln, and produces the influence that is subjected to white rain, and productivity is lower.

After entering the eighties, the kiln manufacturing is faced with energy issue of world, according to the demand of society, some new kiln types occurred." the international pottery comment " of Here it is West Germany be 32 volume the 5th phases (1983) (Interceram), at title is the fast fired tunnel kiln of PET type, HSK type shuttle kiln, RK type roller kiln and the fast fired tunnel kiln of once reporting in the article of " new trend of kiln technology " (New trends in Kiln Technology) of SE type individual layer, the level of automation height of these kilns, life-span is long, fault is few, but its complex structure, the manufacturing cost height.

Outside kiln type research topic, how to recycle waste heat effectively, also be one of problem of kiln research.Utilizing residual-heat exchanger to reclaim useless cigarette waste heat, is that flue gas loop and air to be heated are separated, and carries out heat exchange with heat exchanger between two kinds of fluids.Shortcoming is to have increased auxiliary facility.Recycling that using residual heat from kiln furnace comes wet basis is dehydrated is the problem of always study for many years, and various countries people relevant with kiln have obtained some effects struggle for this reason.West Germany's " international pottery comment " 32 volume the 3rd phases (1983), once be to report in " annular kiln waste heat recovery " (Recovery of Waste Heat from Annular Kilns) digest at title, Czechoslovakia brick field main office has set up the residual neat recovering system engineering in 1981 at the Dolnf-Kounice brick field, this project is to utilize partition wall that annular kiln is divided into 4 sections endless belt, on partition wall, be provided with the hole of being furnished with moving valve, endless belt is communicated in twos, residual neat recovering system also comprises the induced exhaust that is arranged on the Yao Ding both sides, mixing section and blower fan, utilize this systems engineering to dehydrate processing to wet basis with the cooling zone waste heat with after freezing air mixes.Its shortcoming is, damming in kiln has reduced firing chamber's capacity, and the residual neat recovering system pipeline is longer, is set at the kiln top again, and facility investment is bigger, but also the part heat that scattered and disappeared.

In view of the foregoing, purpose of the present invention just is to provide a kind of waste heat of can recycling to dehydrate, do not need wet basis to dry in the air or the furnace construction of kiln to wet basis.

S type of the present invention is worn fork kiln (accompanying drawing), 1 the successive tunnel oven body of heater that factory building (38) is arranged, be linked to be by several firing chambers (4), the wicket (5～10) of firing chamber (4), is arranged on (4) top, firing chamber and the flue net (12～30) that communicates with its several fuel ports (11) that communicate, fuel flap, with firing chamber (4), the pump drainage cigarette facility (not shown) that links to each other with above-mentioned flue net (12～30), several cooling zone hot air passages (31,32), wet basis dewatering element, air lock, wind shelves etc.

Above-mentioned kiln body is made up of 2 outer kiln tube (1,2) and 1 inner kiln tubes (3) that are several firing chambers (4) are linked to be that are several firing chambers (4) are linked to be, article 2, the two ends of outer kiln tube (1,2) are interconnected and form annular, inner kiln tube (3) is set between 2 outer kiln tubes (1,2), 2 bends that its two ends are connected mutually with 2 outer kiln tubes (1,2) respectively are communicated with, and make whole kiln pipe become 1 head and the tail with alphabetical S and are connected to about it formed double-doughnut behind 2 bends.

Above-mentioned cooling zone hot air passage (31,32) is horizontally installed on along the kiln body on the bottom surface of kiln, and its length is about 1 meter.One end of cooling zone hot air passage (31,32) is communicated with the firing chamber (4) of inner kiln tube (3), and its other end is communicated with the firing chamber (4) of outer kiln tube (1 or 2).In cooling zone hot air passage (31,32), be provided with air lock (33,34).

Above-mentioned cooling zone hot air passage (31,32), be designed to coexist 12 sections of the mutual perforation that is 1 grade of step on the kiln body cross section that is positioned at firing chamber middle part of its central axis, wherein, 1 section is set on the kiln baseplane and with the firing chamber (4) of outer kiln tube (1 or 2) and communicates, and 1 section is configured to communicate with the firing chamber (4) of inner kiln tube (3) and parallel and be higher than above-mentioned section in addition.Above-mentioned flue net (12～30) has humidity discharging flue net (23～30) and roasting flue net (12～22).

Above-mentioned humidity discharging flue net (23～30), by 2 along the kiln pipe vertically be separately positioned on 2 outer kiln tubes (1,2) outsides humidity discharging flue collector (23,24), several are all along kiln pipe arranged transversely and be communicated with humidity discharging branch flue (25) on humidity discharging flue collector (23,24) and several are set at firing chamber's (4) top outer of outer kiln tube (1,2) and are communicated with its firing chamber (4) and the humidity discharging mouth (30) of humidity discharging branch flue (25), air lock (28,29) formation in the humidity discharging flue.

Above-mentioned humidity discharging flue collector (23,24), be arranged on the top of wicket (5～8), near kiln pipe (1,2), be parallel to the kiln bottom surface, its shape of cross section is a rectangle, above-mentioned humidity discharging branch flue (25), the upright branch flue (26) that is communicated with by the one end that is the vertical shaft state and humidity discharging flue collector (23 or 24) flat branch flue (27) formation that the other end is communicated with the other end of upright branch flue (26) with being communicated with the humidity discharging mouth (30) of firing chamber (4) top outer with one end parallel at the bottom of the kiln.Air lock (28,29) is arranged on the connection section that upright branch flue (26) and humidity discharging flue collector (23,24) join.

Above-mentioned roasting flue net (12～22), 4 roasting flue collectors (12～15) that vertically are provided with along the kiln body are arranged, wherein, article 2, roasting flue collector (12,13) is separately positioned on the outside of 2 outer kiln tubes (1,2), and remaining 2 roasting flue collector (14,15) is separately positioned between inner kiln tube (3) and 2 outer kiln tubes (1,2).Several roasting branch flues (16) on the roasting flue collector (12～15) all are set on the kiln bottom surface.

Above-mentioned roasting flue collector (12～15) all is arranged on the top of wicket (5～10), is parallel to the kiln bottom surface, and coexists on the plane with humidity discharging flue collector (23,24), and the shape of cross section of roasting flue collector is a rectangle.

Above-mentioned wet basis dewatering element (36,37) is the component part of roasting flue collector (12～15) and/or humidity discharging flue collector (23,24).

Above-mentioned wet basis dewatering element (36,37) is the flue sheet of the top of roasting flue collector (12～15) and/or humidity discharging flue collector (23,24), is inlayed by the solid steel reinforced concrete frid of house-like floor to piece together.

S type of the present invention is worn the operation of fork kiln, be that calcining matter is motionless, the circular flow method that loading of kiln band, preheating zone, roasting band, insulation belt, cooling zone, kiln discharge band, scarfing cinder band move in kiln successively continuously, in 1 loop cycle of operation, include the operation of 1 S type and 1 and wear fork and move (seeing also accompanying

drawing

1,13～20).The operation of S type is from S type head, along S type trend, through a side outer kiln tube (1 or 2), inner kiln tube (3), opposite side outer kiln tube (2 or 1), runs to S type tail; Wearing the fork operation, is to be right after S type tail to rise, and wears fork through inner kiln tube (3) again and runs on the S type head.

It is in service that above-mentioned S type is worn fork, be with pack into the firing chamber (4) of the outer kiln tube (1,2) except that wicket portion passage (40) of a part of wet basis direct code, dehydrate after the processing again sign indicating number pack into kiln pipe (4) and above-mentioned wicket portion's passage (40) of inner kiln tube (3) on the wet basis dewatering element (36,37) and all the other wet basis sign indicating numbers are piled up, kiln discharge, scarfing cinder, the loading of kiln engineering of the firing chamber (4) of inner kiln tube (3) need be used the wicket (5,9 or 6,10) of the firing chamber (4) of above-mentioned wicket portion's passage (40) and inside and outside kiln pipe (1,2,3) simultaneously.

It is in service that above-mentioned S type is worn fork, it is the way that adopts the air lock (33,34) in the controlled chilling band hot air passage (31,32), warm air with inner kiln tube (3) cooling zone firing chamber, through the firing chamber that cooling zone hot air passage (31,32) is introduced outer kiln tube (1,2), the wet basis of packing in it is dehydrated processing.Simultaneously, by control humidity discharging air lock (28,29), moisture is discharged kiln through humidity discharging flue net (23～30).

S type of the present invention is worn the fork kiln, and its advantage is that relatively simple for structure, construction is than being easier to; Utilize cooling zone, roasting, humidity discharging waste heat, and kiln is dissipated in the heat radiation in the factory building, the Wen Ji on wet basis in the outer kiln tube and the wet basis dewatering element dehydrates processing.Above-mentioned advantage, constitute characteristics of the present invention, make the Bricks and Tiles Plant that the requisite kiln of original common annular kiln, drying plant or the wet basis field of drying in the air not only need be set, and do not increase energy consumption and just can provide water content lower to roasting, the butt that water ratio is more stable, thus roasting time shortened, improved the quality of product, improve productivity and reduced energy consumption, reduced cost.Also owing to the all-work from the base to the kiln discharge all carries out in factory building, therefore produce the influence of Changes in weather such as not being subjected to white rain and conversion in season, the quality of product and output are all more stable, carry out the exhausting cooling during kiln discharge in addition, the workman does not need to work down with high temperature in the open, and labor condition is more superior.

Below, again with embodiment and comparative examples accompanying drawing, S type of the present invention is worn fork kiln and S type crossling operation method be further described.

Being simply described as follows of accompanying drawing:

Fig. 1 is the floor map that S type of the present invention is worn fork kiln embodiment.

Fig. 2 is the synoptic diagram that the firing chamber of the embodiment of the invention divides.

Fig. 3 is the P-P sectional view of Fig. 1.

Fig. 4 is the A-A sectional view of Fig. 3.

Fig. 5 is the D-D sectional view of Fig. 6.

Fig. 6 is the B-B sectional view of Fig. 3.

Fig. 7 is the C-C sectional view of Fig. 3.

Fig. 8 is the E-E sectional view of Fig. 7.

Fig. 9 is the F-F sectional view of Fig. 7.

Figure 10 is the M-M sectional view of Fig. 1.

Figure 11 is the N-N sectional view of Fig. 1.

Figure 12 wind gear that is the embodiment of the invention when operation is put the synoptic diagram with wicket portion passage.

Figure 13～20th, the stage operation synoptic diagram of the embodiment of the invention.

The connotation of each symbol is as follows among the above-mentioned figure:

1,2-outer kiln tube 3-inner kiln tube

5～the 10-of 4-firing chamber wicket

11-fuel port 12～15-roasting flue collector

16～18-roasting branch flue

19～22-roasting air lock

23,24-humidity discharging flue collector

25～27-humidity discharging branch flue

28,29-humidity discharging air lock

30-humidity discharging mouth

31,32-cooling zone hot air passage

33,34-waste heat air lock

35-main air lock

36,37-wet basis dewatering plate

The 38-factory building

The 39-movable observing hole of cleaning the street

40-wicket portion passage

41～80-firing chamber numbering

81,82-wind shelves

Among the figure arrow show hot blast to.

Embodiment 1

S type of the present invention is worn the fork kiln, common brick field factory building 38 is arranged, be linked to be 1 successive tunnel oven body of heater by 40 firing chambers 41～80, the wicket 5～10 of above-mentioned firing chamber 41～80, several fuel ports 11 that are arranged on 41～80 tops, above-mentioned firing chamber and communicate with it, the fuel flap, the flue net 12～30 that communicates with above-mentioned firing chamber 41～80, the pump drainage blower fan (not shown) that links to each other with above-mentioned flue net 12～30, cooling zone hot air passage 31,32,2 row wet basis dewatering plates 36,37, and air lock and wind shelves etc.

Above-mentioned kiln body is made up of 1,2 and 1 inner kiln tubes 3 of 2 outer kiln tubes that are parallel to each other that firing chamber 41～80 is linked to be.The two ends of above-mentioned 2

outer kiln tubes

1,2 are interconnected, and formation resembles the annular the original common annular kiln kiln pipe.Above-mentioned inner kiln tube 3 is set between 2

outer kiln tubes

1,2, and and 2

outer kiln tubes

1,2 between distance all be about 1 meter, 2 bends connections that the two ends of inner kiln tube 3 are connected mutually with 2

outer kiln tubes

1,2 respectively make whole kiln pipe become 1 head and the tail with alphabetical S and are connected to about it formed double-doughnut behind 2 bends.The length of above-mentioned 40 firing chambers 41～80 respectively is about 6 meters.It is that there are 12 straight firing chambers 42～53 at outer kiln tube 1 middle part, and 1 curved firing chamber 41 and 54 are respectively arranged at its two ends that the firing chamber of above-mentioned

outer kiln tube

1,2 and inner kiln tube 3 divides (referring to Fig. 2); There are 12 straight firing chambers 68～79 at outer kiln tube 2 middle parts, and 1 curved firing chamber 67 and 80 are respectively arranged at its two ends; Inner kiln tube 3 has 12 straight firing chambers 55～66.Between above-mentioned firing chamber and firing chamber, be provided with wicket, all wicket amounts to 39.Wherein, between the firing chamber of the straight firing chamber 41～54 of

outer kiln tube

1,13 wickets 5 of side outside it are arranged; Between the firing chamber of the straight firing chamber 67～80 of

outer kiln tube

2,13 wickets 6 of side outside it are arranged; Between the curved firing chamber 67 of the curved firing chamber 41 of outer kiln tube 1 and

outer kiln tube

2,1 wicket 7 of side outside it is arranged; Between the curved firing chamber 80 of the curved firing chamber 54 of outer kiln tube 1 and

outer kiln tube

2,1 wicket 8 of side outside it is arranged; Totally 6 wickets 9 between the firing chamber 55 and 56 of inner kiln tube 3,57 and 58,59 and 60,61 and 62,63 and 64,65 and 66 are over against the wicket 5 of outer kiln tube 1; Totally 5 wickets 10 between the firing chamber 56 and 57 of inner kiln tube 3,58 and 59,60 and 61,62 and 63,64 and 65, over against the wicket 6 of outer kiln tube 2.At whole kiln pipe top, horizontal along the kiln pipe, be provided with and resemble plurality of rows fuel port uniform the original common annular kiln (or claiming coal feeding hole) 11, every row has 3 fuel ports 11, and the distance between each row is about 1 meter.Fuel port 11 is provided with fuel flap (not shown).The basic structure of the firing chamber 41～80 of above-mentioned kiln body, wicket 5～10, fuel port 11, fuel flap etc. is similar to original common annular kiln all.

Above-mentioned cooling zone air channel 31,32(are referring to Fig. 3,7,8) amount to 24, all be horizontally installed between inner kiln tube 3 and

outer kiln tube

1 or 2 along kiln.Above-mentioned per 2 cooling zone hot air passages 31,32, all be designed to its central axis and on 1 kiln body cross section that is positioned at firing chamber middle part, be 2 sections of mutual perforation of 1 grade of step, wherein 1 section is set on the kiln baseplane and with the firing chamber of

outer kiln tube

1 or 2 and communicates, another section is configured to communicate with the firing chamber of inner kiln tube 3 and equality and be higher than 1 section that firing chambers above-mentioned and

outer kiln tube

1 or 2 communicate, and above-mentioned 2 sections length overall is about 1 meter.On above-mentioned 2 sections stages of joining, be provided with 1 waste heat air lock 33 or 34.Above-mentioned per 1 waste heat air lock 33 and 34 all has 1 to stretch out the outer air lock handle in kiln top vertically, by above-mentioned air lock handle, opens or closes waste heat air lock 33,34.The configuration of above-mentioned 24 cooling zone hot air passages 31,32 is, between firing chamber 55 and 53,56 and 52,57 and 51,58 and 50,59 and 49,60 and 48,61 and 47,62 and 46,63 and 45,64 and 44,65 and 43,66 and 42, respectively be provided with a cooling zone hot air passage 31, in above-mentioned cooling zone hot air passage 31, waste heat air lock 33 is installed; Between

firing chamber

55 and 79,56 and 78,57 and 77,58 and 76,59 and 75,60 and 74,61 and 73,62 and 72,63 and 71,64 and 70,65 and 69,66 and 68, respectively be provided with 1 cooling zone hot air passage 32, in above-mentioned cooling zone hot air passage 32, waste heat air lock 34 is installed.The flat branch flue broadly similar of the shape of cross section of above-mentioned cooling zone hot air passage 31,32 and original common annular kiln, the structure of above-mentioned waste heat air lock 33,34 is similar to the air lock of original common annular kiln.

Above-mentioned flue net 12～30 has humidity discharging flue net 23～30 and roasting flue net 12～22.

Above-mentioned humidity discharging flue net 23～30(is referring to Fig. 3,4,5,6), by 23,24 and 28 humidity discharging branch flues 25 of 2 humidity discharging flue collectors, and 28 humidity discharging mouths 30 are formed.Above-mentioned 28 humidity discharging mouths 30, be separately positioned on

outer kiln tube

1,2 41～54,67～80 stage casings, 28 firing chambers top outer and communicate with the firing chamber.Above-mentioned humidity discharging flue collector 23 is set at the kiln body top of top of wicket 5 in the outside of outer kiln tube 1 and the parallel outer kiln tube 1 that nestles up; Above-mentioned humidity discharging flue collector 24 is set at the kiln body top of top of wicket 6 in the outside of outer kiln tube 2 and the parallel outer kiln tube 2 that nestles up.One end of above-mentioned 2 humidity discharging

flue collectors

23,24 is closed respectively, and its other end links to each other with the pump drainage blower fan respectively, between humidity discharging

flue collector

23,24 and pump drainage blower fan, main air lock 35 separately is installed.The cross section rectangular shaped of above-mentioned humidity discharging flue collector 23,24.On per 2 cross sections that all are arranged on 1 kiln body that is positioned at firing chamber middle part of above-mentioned 28 humidity discharging branch flues 25, wherein there are 24 humidity discharging branch flues 25 to be set on same 1 cross section with above-mentioned cooling zone hot air passage 33,34.Above-mentioned per 1 humidity discharging branch flue 25 all is made up of with the flat branch flue 27 that humidity discharging mouth 30 is communicated with and is parallel to the kiln bottom surface 1 upright branch flue 26 that is the vertical shaft state and 1.Above-mentioned upright branch flue 26 and flat branch flue 27 mutual vertical connections.In above-mentioned 28 humidity discharging branch flues 25, the upright branch flue 26 of 14 humidity discharging branch flues 25 respectively with humidity discharging flue collector 23 vertical connections.At its joining place 1 humidity discharging air lock 28 is installed, its flat branch flue 27 is communicated with the humidity discharging mouth 30 of 14 firing chambers 41～54 of outer kiln tube 1 respectively; The upright branch flue 26 of 14 humidity discharging branch flues 25 in addition respectively with humidity discharging flue collector 24 vertical connections, at its joining place 1 humidity discharging air lock 29 is installed, its flat branch flue 27 is communicated with the humidity discharging mouth 30 of 14 firing chambers 67～80 of outer kiln tube 2 respectively.Above-mentioned 14 humidity discharging air locks 28 and 14 humidity discharging air locks 29 all have 1 to stretch out the outer air lock handle in kiln top separately, open and close air lock by the air lock handle.The shape of cross section of the upright branch flue 26 peaceful branch flues 27 of above-mentioned humidity discharging branch flue 25 is respectively with the shape of cross section broadly similar of the upright branch flue peace branch flue of original common annular kiln.The structure of above-mentioned humidity discharging air lock 28,29 is similar to the air lock of original common annular kiln.

Above-mentioned roasting flue net 12～22(sees also Fig. 3,4,7,9), form by 4 roasting flue collectors 12～15 and 47 roasting branch flues 16.Above-mentioned 4 roasting flue collectors 12～15 and above-mentioned 2 humidity discharging

flue collectors

23,24 all are set on the same plane that is parallel to the kiln bottom surface.Above-mentioned roasting flue collector 14, vertical along kiln, be set in parallel between inner kiln tube 3 and the outer kiln tube 1.Above-mentioned roasting flue collector 15, vertical along kiln, be set in parallel between inner kiln tube 3 and the outer kiln 2.The middle part of above-mentioned roasting flue collector 12 is arranged on the kiln body top of top of the wicket 5 in outer kiln tube 1 outside and the parallel outside that abuts against humidity discharging flue collector 23.The middle part of above-mentioned roasting flue collector 13 is arranged on the kiln body top of top of the wicket 6 in outer kiln tube 2 outsides and the parallel outside that abuts against humidity discharging flue collector 24.Coexist

roasting flue collector

12 and 13 end separately of kiln one end respectively revolves to ground relatively and is docked and connected mutually after turning 90 degrees, and forms along horizontal roasting the

flue collector

12 and 13 horizontal end separately of kiln body; At roasting flue collector 14,15 end separately of this same end of kiln, sealing respectively.The kiln the other end coexists, promptly be provided with

roasting flue collector

12 and 13 end separately of an end of pump drainage blower fan, relatively to ground respectively revolve turn 90 degrees after, be communicated with the pump drainage blower fan separately again, form along the horizontal

roasting flue collector

12,13 of the kiln body horizontal end of the other end separately; At roasting flue collector 14,15 the other end separately of this same end of kiln, be communicated with the above-mentioned horizontal end of above-mentioned roasting flue collector 12, the above-mentioned horizontal end of above-mentioned roasting flue collector 13 respectively.Separately and between the pump drainage blower fan, main air lock 35 separately is installed at above-mentioned roasting flue collector 12,13.The cross section rectangular shaped of above-mentioned roasting flue collector 12～15.Per 1 roasting branch flue of above-mentioned 47 roasting branch flues 16 all is the upright branch flue 17 of vertical shaft state by 1 and the flat branch flue 18 that is set on the kiln baseplane is formed.Above-mentioned upright branch flue 17 and flat branch flue 18 mutual vertical connections.In above-mentioned 47 roasting branch flues 16, per 2 of 28 roasting branch flues 16 are arranged, all be set on the cross section with per 2 same 1 kiln body that is positioned at the middle part, firing chamber of above-mentioned 28 humidity discharging branch flues 25, wherein, article 14, the middle part vertical connection of the upright branch flue 17 of roasting branch flue 16 and roasting flue collector 12, its flat branch flue 18 is communicated with 14 firing chambers 41～54 of outer kiln tube 1 respectively, the upright branch flue 17 of other 14 roasting branch flues 16 and the middle part vertical connection of roasting flue collector 13, its flat branch flue 18 is communicated with 14 firing chambers 67～80 of outer kiln tube 2 respectively; There are 8 roasting branch flues 16 to be separately positioned on each 4 of the kiln two ends on totally 8 kiln body vertical sections, wherein, article 4, the upright branch flue 17 of the per 2 roasting branch flues 16 in, respectively with

roasting flue collector

12,13 horizontal end vertical connection separately at the same end of kiln, its flat branch flue 18 is communicated with firing chamber 54,80 respectively, the upright branch flue 17 of the per 2 roasting branch flues 16 in addition 4, with roasting flue collector 12, the 13 horizontal end vertical connection separately of the kiln the other end that coexists, its flat branch flue 18 is communicated with firing chamber 41,67 respectively respectively; There are 11 roasting branch flues 16 to be separately positioned on the kiln body cross section of wicket 9,10 of inner kiln tube 3, wherein, article 5, the upright branch flue 17 of roasting branch flue 16 and roasting flue collector 14 vertical connections, its flat branch flue 18 is communicated with the firing chamber 56,58,60,62,64 of inner kiln tube 3 respectively, the upright branch flue 17 and roasting flue collector 15 vertical connections of 6 roasting branch flues 16 in addition, its flat branch flue 18 is communicated with the firing chamber 55,57,59,61,63,65 of inner kiln tube 3 respectively.The firing chamber 66 of inner kiln tube 3 uses above-mentioned 2 roasting branch flues 16 that turn on

roasting flue collector

12,13 horizontal ends.Joining place in that the upright branch flue 17 of above-mentioned roasting branch flue 16 is communicated with

roasting flue collector

12,13,14,15 respectively all is provided with 1

roasting air lock

19,20,21,22 separately.All the roasting air lock amounts to 47, in roasting flue collector 12,18 roasting air locks 19 is arranged; In roasting flue collector 13,18 roasting air locks 20 are arranged; In roasting flue collector 14,5 roasting air locks 21 are arranged; In roasting flue collector 15,6 roasting air locks 22 are arranged.Above-mentioned 47 roasting air locks all have 1 to stretch out the outer air lock handle in kiln top separately, by the air lock handle, open, close the roasting air lock.Upright branch flue 17 peaceful branch flues 18 shape of cross section separately of above-mentioned roasting branch flue 16 is respectively with the peaceful branch flue broadly similar of the upright branch flue of original common annular kiln.The air lock structural similitude of the structure of above-mentioned roasting air lock and original common annular kiln.

Above-mentioned 2 row wet basis dewatering plates 36,37(are referring to Fig. 3,5,9), all by many same shape sizes.The solid steel reinforced concrete frid edge of house-like floor pieces together.Above-mentioned wet basis dewatering plate 36, be with above-mentioned frid across and the top and the edge that are listed in roasting flue collector 12 and humidity discharging flue collector 23 be combined into one, 12,23 cappings of above-mentioned 2 flue collectors are got up, and becoming its shape of cross section of formation all is the cover plate of above-mentioned 2 flue collectors of orthogonal 12,23 tops.Above-mentioned wet basis dewatering plate 37, also be with above-mentioned frid across and the top and the edge that are listed in roasting flue collector 13 and humidity discharging flue collector 24 be combined into one, 13,24 cappings of above-mentioned 2 flue collectors are got up, and becoming its shape of cross section of formation all is the cover plate of above-mentioned 2 flue collectors of orthogonal 13,24 tops.

In addition, on the bottom surface of kiln, there are 36 flat branch flue 18 straight lines that are communicated with the roasting branch flue 16 on

outer kiln tube

1,2 respectively with 36 to connect, when needed the movable observing of breakdown or the sealing hole 39 of cleaning the street.

At kiln in when operation, the employing calcining matter is motionless, dependence drops into fuel port 11 forward in turn with fuel, roasting is moved, and the continuous circulating S type that promotion preheating zone, roasting band, insulation cooling zone, cooling kiln discharge band (cooling zone overlaps with insulation belt afterbody and kiln discharge band), scarfing cinder band, loading of kiln band move forward successively along with the progress of roasting is worn the fork operation.

Above-mentioned S type is worn fork operation (referring to Figure 12～20), in 1 loop cycle, includes 1 S type operation and 1 and wears fork and move.Above-mentioned S type operation, if from S type head is the stem of firing chamber 41, then move towards along the S type, through the firing chamber 41 → 54 of outer kiln tube 1, the firing chamber 55 → 66 of inner kiln tube 3, the firing chamber 67 → 80 of outer kiln tube 2, running to S type tail is the afterbody of firing chamber 80, above-mentionedly wears fork operation, is that and then S shape tail is that the afterbody of firing chamber 80 rises, through the firing chamber 55 → 66 of inner kiln tube 3, wearing fork, to run to S shape head be that the stem of firing chamber 41 is ended.Then, 41 the stem from the firing chamber begins following 1 round-robin operation again, so goes round and begins again, successively.From as can be known above-mentioned, in 1 loop cycle, whole firing chambers 41～54,67～80 of outer kiln tube 1,2 respectively move 1 time, and whole firing chambers 55～66 of inner kiln tube 3 respectively move 2 times, and total working line length is about 320 meters.

Above-mentioned S type crossling operation method, it is about 1/2nd wet basis with the base Workshop Production, sign indicating number piles up on the wet basis dewatering plate 36,37, because wet basis dewatering plate 36,37, it is respectively the upper cover plate of roasting flue collector 12 and humidity discharging flue collector 23, roasting flue collector 13 and humidity discharging flue collector 24, therefore, but the hot cigarette direct heating wet basis dewatering plate 36,37 in the flue; In addition, also because wet basis dewatering plate 36,37 is set in the brick field factory building 38, the both sides of kiln top, so, the waste heat in the time of just can be and the waste heat of cooling zone very fully roasting, humidity discharging, and kiln is dissipated in factory building 38 spatial heat radiations and all uses, wet basis is dehydrated processing, also because water vapor is not with in above-mentioned waste heat and heat radiation, therefore, the water content of resulting butt is lower after treatment, and water ratio is more stable.Above-mentioned butt is used for sign indicating number and is contained in the pairing wicket of wicket 5～8 portion passage 40 of the firing chamber 55～66 of inner kiln tube 3 and outer kiln tube 1,2, uses for roasting.All the other wet basis that above-mentioned base workshop is produced are contained in by direct code in the firing chamber 41～54,67～80 except that above-mentioned wicket portion passage 40 of outer kiln tube 1,2, for firing usefulness.

Above-mentioned S type crossling operation method, each operation with shared firing chamber's number is, preheating zone a1, a2, a3, a4 take 4 firing chambers, roasting band b1, b2, b3 take 3 firing chambers, insulation cooling zone c1, c2, c3, c4 take 4 firing chambers, cooling kiln discharge band d1, d2, d3, d4 take 4 firing chambers, and scarfing cinder band e takies 1 firing chamber, and loading of kiln band f1, f2, f3, f4 take 4 firing chambers.The cooling zone of above-mentioned S type crossling operation method overlaps with insulation cooling zone afterbody c4 and cooling kiln discharge band d1, d2, d3, d4.Above-mentioned S type crossling operation method, each operation adds up to 20 with shared firing chamber, and all the other 20 firing chamber's sign indicating numbers are being adorned butt or wet basis, are in waiting status.

Above-mentioned S type crossling operation method includes outer kiln tube, 2 kinds of technical process of inner kiln tube.

The technical process of above-mentioned

outer kiln tube

1,2 is:

1, wet basis loading of kiln.During loading of kiln in wicket portion passage 40 sign indicating number base not, the firing chamber that gives over to inner kiln tube 3 makes passage and uses when kiln discharge, scarfing cinder, loading of kiln.

2, leave standstill homogenize.Make the moisture homogenizing of wet basis.Last 4 hours.

3, humidity discharging.Open humidity discharging air lock 28 or 29, under the suction function of pump drainage blower fan, moisture from humidity discharging mouth 30, is discharged kiln through humidity discharging branch flue 25, humidity discharging

flue collector

23 or 24.

4, the envelope kiln is waited for.In position, wicket both sides, with wind shelves 81,82 sealing firing chambers.At this moment, wicket portion passage 40 is still unimpeded, and each firing chamber is in closed state separately separately.

5, dehydrate.Open waste heat air lock 33 or 34 and humidity discharging air lock 28 or 29,, extract the waste heat of the firing chamber of inner kiln tube 3 cooling zone c4, d1, d2, d3, d4, wet basis is dehydrated processing through cooling zone hot air passage 31 or 32.

6, wait for.Close waste heat air lock 33 or 34 and humidity discharging air lock 28 or 29, each firing chamber is in closed state again separately separately, and at this moment, wicket portion passage 40 is still unimpeded.

7, filling wicket portion passage 40.Dismounting is positioned at wicket wind shelves 82 on one side, use through wet basis dewatering plate 36,37 dehydrate handle after resulting butt sign indicating number be contained in the wicket portion passage 40, with the rear enclosed wicket.

8, preheating.Open wind shelves 81, roasting

air lock

19 or 20, utilize the hot blast that attracts from the roasting band to carry out preheating.

9, roasting.Open the fuel flap, throw the coal roasting from fuel port 11.

10, insulation.Close roasting

air lock

19 or 20, cover the fuel flap, be incubated.

11, cooling.Self-heat conserving cooling zone afterbody c4 rises, and opens cooling zone humidity discharging air lock 28 or 29 and carries out the exhausting cooling.

12, kiln discharge.Open wicket, still carry out the exhausting cooling, simultaneously kiln discharge.

13, scarfing cinder.After closing humidity discharging air lock 28 or 29, carry out scarfing cinder.

Then, repeat above-mentioned technical process, once more loading of kiln ...

The technical process of above-mentioned inner kiln tube 3 and the technical process of original common annular kiln are basic identical, and its flow process is:

1. butt loading of kiln.The wicket portion passage of reserving when using wicket 5 or 6 or 7 or 8, the loading of kiln of outer kiln tube firing chamber of outer kiln tube firing chamber 40, the wicket 9 or 10 of inner kiln tube firing chamber, will through wet basis dewatering plate 36,37 dehydrate handle after the resulting butt sign indicating number firing chamber of packing into.

2. the envelope kiln is waited for.With wind shelves 81 packing firing chambers, sealing wicket 9 or 10.

3. preheating.Open wind shelves 81, roasting air lock 21 or 22, utilize the hot blast that attracts from the roasting band to carry out preheating.

4. roasting.Open the fuel flap, throw the coal roasting from fuel port 11.

5. insulation.Close roasting air lock 21 or 22, cover the fuel flap, be incubated.

6. cooling.Open the waste heat air lock 33 or 34 and corresponding humidity discharging air lock 28 or 29 of the cooling zone that self-heat conserving cooling zone afterbody c4 rises, the suction freezing air cools off, and with this cooling zone waste heat suction outer kiln tube firing chamber, wet basis is dehydrated processing simultaneously.

7. kiln discharge.Open wicket 9 or 10,, implement kiln discharge through the wicket 5 or 6 or 7 or 8 of above-mentioned wicket 9 or 10, wicket portion passage 40, outer kiln tube 1,2.Simultaneously, still continue its waste heat suction outer kiln tube firing chamber.

8. scarfing cinder.Close waste heat air lock 31,32 and humidity discharging air lock 28 or 29, use above-mentioned kiln discharge passage to carry out scarfing cinder.

Then, repeat above-mentioned technical process, once more loading of kiln ...

Above-mentioned S type crossling operation method, the whole process of 1 loop cycle can be divided into following unremitting 8 stages.

The 1st stage (referring to Fig. 1,20,13), be that roasting band head b1 41 runs to 46 from the firing chamber, correspondingly head a1 in preheating zone 45 runs to 50 from the firing chamber, insulation cooling zone head c1 64 runs to 43 from the firing chamber, cooling kiln discharge band head d1 60 runs to 65 from the firing chamber, scarfing cinder band e 56 runs to 61 from the firing chamber, and loading of kiln band head f1 55 runs to 60 from the firing chamber, and the loading of kiln magnetic tape trailer f4 of portion 78 runs to 57 from the firing chamber.During this period, open waste heat air lock 34 in turn, with the waste heat of cooling zone firing chamber 61～66 through cooling zone hot air passage 32, suction firing chamber 73,72,71,70,69,68 respectively, and, wet basis is dehydrated processing through the cooling zone waste heat suction firing chamber 67 of kiln canal curvature portion with firing chamber 66,41; Close firing chamber's 55～60 corresponding last waste heat air locks 33 that circulation is opened in turn; A last circulation continues, continue to use wicket 10, wicket portion passage 40, wicket 6,8,7, outer side to outer kiln tube 2, the loading of kiln of the scarfing cinder of the kiln discharge of the firing chamber 57～65 of pipe 3, firing chamber 56～61, firing chamber 55～60 in implementing, use wicket 6,8 are implemented the loading of kiln of the firing chamber 78～80 of outer kiln tube 2.

The 2nd stage (referring to Fig. 1,13,14), be that roasting band head b1 47 runs to 53 from the firing chamber, correspondingly head a1 in preheating zone 51 runs to 57 from the firing chamber, insulation cooling zone head c1 44 runs to 50 from the firing chamber, cooling kiln discharge band head d1 66 runs to 46 from the firing chamber, scarfing cinder band e 62 runs to 42 from the firing chamber, and loading of kiln band head f1 61 runs to 41 from the firing chamber, and the loading of kiln magnetic tape trailer f4 of portion 58 runs to 64 from the firing chamber.During this period, be closed in firing chamber's 61～66 corresponding waste heat air locks 34 that the 1st stage opened successively; With the waste heat of cooling zone firing chamber 41～47, by humidity discharging mouth 30, through humidity discharging branch flue 25, suction humidity discharging flue collector 23 is used for the wet basis on the wet basis dewatering plate 36 is carried out processed; Use wicket 10, wicket portion passage 40, wicket 6,7, continue to implement the kiln discharge of the firing chamber 63～66 of inner kiln tube 3, the scarfing cinder of firing chamber 62～66, the loading of kiln of firing chamber 58～66 to the outer side of outer kiln tube 2; Use wicket 7,5, implement the kiln discharge of firing chamber 41～46, the scarfing cinder of firing chamber 41,42, the loading of kiln of firing chamber 41.

The 3rd stage (referring to Fig. 1,14,15), be that roasting band head b1 54 runs to 60 from the firing chamber, correspondingly head a1 in preheating zone 58 runs to 64 from the firing chamber, insulation cooling zone head c1 51 runs to 57 from the firing chamber, cooling kiln discharge band head d1 47 runs to 53 from the firing chamber, scarfing cinder band e 43 runs to 49 from the firing chamber, and loading of kiln band head f1 42 runs to 48 from the firing chamber, and the loading of kiln magnetic tape trailer f4 of portion 65 runs to 45 from the firing chamber.During this period, cooling zone is in outer kiln tube 1 operation, and its waste heat is drawn into humidity discharging flue collector 23.Simultaneously, kiln discharge band, scarfing cinder band, loading of kiln band all in outer kiln tube 1 operation, therefore, use wicket 7,5, to the outer side of outer kiln tube 1, implement its kiln discharge, scarfing cinder and loading of kiln.

The 4th stage (seeing also Fig. 1,15,16), be that roasting band head b1 61 runs to 66 from the firing chamber, correspondingly head a1 in preheating zone 65 runs to 70 from the firing chamber, insulation cooling zone head c1 58 runs to 63 from the firing chamber, cooling kiln discharge band head d1 54 runs to 59 from the firing chamber, scarfing cinder band e 50 runs to 55 from the firing chamber, and loading of kiln band head f1 49 runs to 54 from the firing chamber, and the loading of kiln magnetic tape trailer f4 of portion 46 runs to 51 from the firing chamber.During this period, open firing chamber's 55～60 pairing waste heat air locks 34 in turn, waste heat with above-mentioned firing chamber, through cooling zone hot air passage 32, difference suction firing chamber 79,78,77,76,75,74, and, wet basis is dehydrated processing through the cooling zone waste heat suction firing chamber 80 of kiln canal curvature portion with firing chamber 54,55; Use wicket 10, wicket portion passage 40, wicket 8,6, to the outer side of outer kiln tube 2, wicket 5,8 is used in the kiln discharge of the firing chamber 55～59 of enforcement inner kiln tube 3 and the scarfing cinder of firing chamber 55, continues kiln discharge, scarfing cinder and the loading of kiln of the firing chamber of enforcement outer kiln tube 1.

The 5th stage (referring to Fig. 1,16,17), be that roasting band head b1 67 runs to 72 from the firing chamber, correspondingly head a1 in preheating zone 71 runs to 76 from the firing chamber, insulation cooling zone head c1 64 runs to 69 from the firing chamber, cooling kiln discharge band head d1 60 runs to 65 from the firing chamber, scarfing cinder band e 56 runs to 61 from the firing chamber, and loading of kiln band head f1 55 runs to 60 from the firing chamber, and the loading of kiln magnetic tape trailer f4 of portion 52 runs to 57 from the firing chamber.During this period, the waste heat air lock 34 opened of the 4th stage of closing in turn; Open firing chamber's 61～66 pairing waste heat air locks 33 in turn, cooling zone waste heat with above-mentioned firing chamber, by corresponding cooling zone hot air passage 31, difference is suction firing chamber 47,46,45,44,43,42 in turn, and, wet basis is dehydrated processing through the cooling zone waste heat suction firing chamber 41 of kiln canal curvature portion with firing chamber 66,67; Use wicket 9, wicket portion passage 40, wicket 8,5,, implement the kiln discharge of firing chamber 55～65, the scarfing cinder of firing chamber 56～61, the loading of kiln of firing chamber 52～60 in turn to the outer side of outer kiln tube 1.

The 6th stage (referring to Fig. 1,17,18), be that roasting band head b1 73 runs to 79 from the firing chamber, correspondingly head a1 in preheating zone 77 runs to 57 from the firing chamber, insulation cooling zone head c1 70 runs to 76 from the firing chamber, cooling kiln discharge band head d1 66 runs to 72 from the firing chamber, scarfing cinder band e 62 runs to 68 from the firing chamber, and loading of kiln band head f1 61 runs to 67 from the firing chamber, and the loading of kiln magnetic tape trailer f4 of portion 58 runs to 64 from the firing chamber.During this period, the waste heat air lock 33 that the 5th stage of closing in turn opens continues to use wicket 9, wicket portion passage 40, wicket 5,7, to the outer side of outer kiln tube 1, continues to implement the kiln discharge of firing chamber 63～66, the scarfing cinder of firing chamber 62～66, the loading of kiln of firing chamber 58～66; Open humidity discharging air lock 29 in turn, with cooling zone waste heat suction humidity discharging flue collector 24; Use wicket 7,6,, implement kiln discharge, scarfing cinder and the loading of kiln of outer kiln tube 2 firing chambers in turn to the outer side of outer kiln tube 2.

The 7th stage (referring to Fig. 1,18,19), be that roasting band head b1 80 runs to 60 from the firing chamber, correspondingly head a1 in preheating zone 58 runs to 64 from the firing chamber, insulation cooling zone head c1 77 runs to 57 from the firing chamber, cooling kiln discharge band head d1 73 runs to 79 from the firing chamber, scarfing cinder band e 69 runs to 75 from the firing chamber, and loading of kiln band head f1 68 runs to 74 from the firing chamber, and the loading of kiln magnetic tape trailer f4 of portion 65 runs to 71 from the firing chamber.During this period, continue to open humidity discharging air lock 29 in turn, with cooling zone waste heat suction humidity discharging flue collector 24; Use wicket 6,7,10 and wicket portion passage 40,, continue to implement kiln discharge, scarfing cinder, loading of kiln in turn to the outer side of outer kiln tube 2.

The 8th stage (referring to Fig. 1,19,20), be that roasting band head b1 61 runs to 66 from the firing chamber, correspondingly head a1 in preheating zone 65 runs to 44 from the firing chamber, insulation cooling zone c1 58 runs to 63 from the firing chamber, cooling kiln discharge band head d1 80 runs to 59 from the firing chamber, scarfing cinder band e 76 runs to 55 from the firing chamber, and loading of kiln band head f1 75 runs to 80 from the firing chamber, and the loading of kiln magnetic tape trailer f4 of portion 72 runs to 77 from the firing chamber.During this period, open firing chamber's 55～60 corresponding waste heat air locks 33 in turn, through cooling zone hot air passage 31, with the cooling zone waste heat suction firing chamber 53,52,51,50,49,48 of above-mentioned firing chamber, and 54 pairs of wet basis in cooling zone waste heat suction firing chamber of firing chamber 80,55 are dehydrated processing through kiln canal curvature portion; Use wicket 6,8, continue to implement kiln discharge, scarfing cinder, the loading of kiln of outer kiln tube 2; Use wicket 9, wicket portion passage 40, wicket 8,6, the kiln discharge of firing chamber 55～59, the scarfing cinder of firing chamber 55 are implemented in side outside outer kiln tube 2.

More than 8 stages be 1 circulation, returned for the 1st stage again after circulation ends, carry out following 1 round-robin operation, so go round and begin again, successively.

Adopt above-mentioned S type to wear the fork kiln, recycle waste heat wet basis is dehydrated processing, do not need wet basis to dry in the air or kiln, its annual production can reach 2,000 ten thousand when producing common brick.

Claims

1, the S type is worn the fork kiln factory building, a successive tunnel oven body of heater that is linked to be by several firing chambers, the wicket of firing chamber, be arranged on the top, firing chamber, several fuel ports that communicate with the firing chamber, the fuel flap, the flue net that communicates with the firing chamber, the pump drainage cigarette facility that links to each other with the flue net, air lock, wind shelves etc., above-mentioned kiln body is made of 2 outer kiln tube and 1 inner kiln tubes that are several firing chambers are linked to be that are several firing chambers are linked to be, article 2, the outer kiln tube two ends are connected and form annular, inner kiln tube is set between 2 outer kiln tubes, its two ends are communicated with two bends that 2 outer kiln tubes are connected mutually respectively, make whole kiln pipe become the double-doughnut that 1 head and the tail with alphabetical S is connected to two bends about it, roasting flue net is arranged in the above-mentioned flue net, this roasting flue net has 4 roasting flue collectors that vertically are provided with along the kiln pipe, wherein, article 2, the roasting flue collector is separately positioned on the outside of 2 outer kiln tubes, in addition 2 roasting flue collectors are separately positioned between inner kiln tube and 2 outer kiln tubes, roasting branch flue on the roasting flue collector all is set on the kiln bottom surface, be provided with the roasting air lock at roasting flue collector and the joining place that bakes branch flue, it is characterized in that, on the kiln bottom surface and along the kiln body, be horizontally arranged with several cooling zone hot air passages, one end of this cooling zone hot air passage communicates with the firing chamber of inner kiln tube, the other end communicates with the firing chamber of outer kiln tube, in the cooling zone hot air passage, be provided with air lock, also has humidity discharging flue net in the described flue net, this humidity discharging flue net is by 2 humidity discharging flue collectors that vertically are separately positioned on 2 outer kiln tube outsides along the kiln pipe, several are the humidity discharging branch flue on the humidity discharging flue collector along kiln pipe arranged transversely and connection, the humidity discharging mouth that several are set at outer kiln tube firing chamber top outer and are communicated with firing chamber and humidity discharging branch flue, the air lock that is arranged in the humidity discharging flue constitutes, be provided with the wet basis dewatering element at the top of kiln body, this wet basis dewatering element is the top flue sheet of roasting flue collector and/or humidity discharging flue collector.

2, S type as claimed in claim 1 is worn the fork kiln, it is characterized in that described cooling zone hot air passage is designed to coexist 12 sections of the mutual perforation that is 1 grade of step on the kiln body cross section that is positioned at firing chamber middle part of its central axis, wherein, one section is set on the kiln baseplane and with the firing chamber of outer kiln tube and communicates, another section is designed to communicate with the firing chamber of inner kiln tube and is parallel and be higher than above-mentioned section, and air lock is set on two sections stages of joining.

3, S type as claimed in claim 1 is worn the fork kiln, it is characterized in that described humidity discharging flue collector be arranged on the top of wicket, near the kiln pipe, be parallel to the kiln bottom surface, its shape of cross section is a rectangle, the upright branch flue that described humidity discharging branch flue is communicated with by the one end that is the vertical shaft state and humidity discharging flue collector is communicated with the humidity discharging mouth of firing chamber's top outer with the one end parallel with the kiln bottom surface and flat branch flue that the other end is communicated with the other end of upright flue constitutes, and air lock is arranged on and founds the connection section that branch flue and humidity discharging flue collector join.

4, S type as claimed in claim 1 is worn the fork kiln, it is characterized in that described wet basis dewatering element is pieced together by the solid steel reinforcing bar concrete transverse slat edge of house-like floor.