1. furnace duty:
it is supplied for heating copper inget/slab.
2. Technical parameters and mechanical components
2.1 Main Technical Parameters
|1||Description||Walking beam type copper/brass slab heater|
|2||Material||Copper ,brass,cupro-nickel alloy etc|
Standard Max. weight: 2.75t/piece/(160×420×4600mm)
|4||Heating capacity||Minium 12t/h, 4slab/h(1slab:160×420×4600mm)|
|5||Heating temperature||730~750ºC±5ºC(max 850ºC)|
|8||Heat value||8900Kcal/ Nm3|
|9||Air preheating temperature||250~450ºC|
|10||Heat efficiency of the furnace||≥45%|
|11||Thermal control pattern||Auto/ manual,impulse , remote control|
|Imported flat flame burners of Germany KROM schroder.|
heating zone each burner:23 Nm3/h;soaking zone each burner:15 Nm3/h
KROM schroder.23 Nm3/h;15Nm3/h
|13||Number of burners||Total: 18 PCS,heating zone:8PCS,|
Soaking zone: 10 PCS
|14||Rated burning capacity||Max:334 Nm3/h|
|15||Dimension of the hearth||W5000×H1200×L8000mm|
|17||Total length of furnace||~11m|
|18||Loading and unloading method||End feeding and side discharge|
|19||Loading pattern||Single row,3 zones,preheating zone2.5m,heating|
zone 3.5m,soaking zone 2m
|20||Vertical movement of walking|
|Lifting: 90mm, 90mm|
Lowering: 80mm 80mm
|21||Horizontal travel of walking beams:||500mm|
|22||Heat interchanger||Hot tubular exchanger|
|23||Heated up time||~4 hours|
|24||Quantity of heated up zone||3 zones 4sections|
|25||Material and space||Slab: W420mm; slab in furnace:16pcs;|
Gap between slab and slab: 80mm;
Stroke : 500mm
* Walking Beam Type Slab Heater Technical Data
|Parts Name||Parameters||Guarantee value|
|Slab tapping temperature contrast||±5ºC|
|Slab full-length curvature||≤5mm/m|
|Surface quality||No scratches,|
|Storing materials||≥3 PCS|
|Length measuring bias||±5mm|
|Width measuring bias||±3mm|
|Charging positioning accuracy||±5mm|
|Travel route measuring||±5mm|
|Hearth pressure control accuracy||±10Pa|
|Furnace temperature control accuracy||±5ºC|
|Burner Life||≥3 years|
|Total running deviation(cold)|
|Total running deviation(hot)|
|One walking beam precision||±1.5mm|
|Furnace shell||Furnace wall temperature||Max 45ºC|
|Fiber refractory lining life||≥5 years|
|Bottom furnace refractory life||≥5 years|
|Unloading device||Furnace door opening-close time||7.5min/time|
|Air preheating temperature||≥300ºC|
|Heat exchanger life||≥3 years|
|Exchanger||flue gas exit temperature||≤450ºC|
|Cooling water||Water seal yielding water temperature||Max 60ºC|
|Others||Furnace output||≥ 12t/h|
|Sound from 1m from operating point|
|Furnace thermal efficiency||≥45%|
* Energy and Media Consumption::
|Heat value: 8900Kcal/Nm3|
|3||Soft water||4 m3/h|
|6||Compressed air||0.2 Nm3/time|
2.2 Mechanical Components
2.2.1 Furnace shell
Hearth clearance is 5.5 meters width, 1.2 meters height and 8 meters length. Furnace wall, bottom, top consists of steel structure and refractory material. Refractory material adopts high alumina-ceramic fiber modular (thickness: 350mm), and service temperature is 1100 ° C. Those fiber modular is fixed on furnace wall by stainless steel anchor. Main features of the folded modular: stainless steel structure is buried in 2/3 depth of refractory material. (Furnace shell is made of Q235-A steel plate and reinforced by strengthen steel, and continuous sealing welded with each other to guarantee sufficient strength, it provides an adequate rigidity and air tightness structure, which effectively guarantee reliability and longer service life. When installing the fiber blocks, use special tools work to guarantee refractory hermetic. The refractory pre-compression accurate reaches to over 40%, thus reduce the impact of human factors and ensures the construction quality.
A layer of erosion heat resistant adhesive is coated at surface of fiber modular.
Furnace shell steel plate is coated with two layer of antirust paint; after assembling, surface of shell will be painted with silver paint (or paint on request).
2.2.2 Combustion system
Flat flame burner is supplied by Germany manufacturer, totally 18 sets of burners are designed is this slab heater(soaking zone:10 sets, and heating zone: 8 sets). Burners are mounted at furnace roof. Flame forms round shape which has proper radiation capacity, fast heating speed, better temperature uniformity, and little oxidization. Burner is automatically fired, air-gas ratio has large adjusting range, flame automatic detecting. Fire procedures and heating procedures are controlled by PLC.
2 sets of combustion blowers supply air for the 18 sets of burners. To ensure noise level is less than 85 db (distance:1 meter ), blowers are mounted in a separated room, meet national requirement. Suction port of bowler is designed with air filter, reduce air dust effectively. To minimize vibration, softer rubber pipe links outlet of blower and main air pipe.
Each LNG burner in soaking zone can produce heat 15×8900 Kcal/ hour. Each burner in heating zone can produce heat 23×8900 Kcal/h.
The combustion system mainly consists of manual valve, filter, pressure relief valve, pressure gauge, fast cut off valve, flow rate regulating valve, flame inspector, igniting solenoid valve, purging system, and burner. Etc. Whole system running procedures are controlled by PLC.
Each zone has separate control valve, and burner impulse controller. Air-gas ratio is regulated at a proper level, so that ensures a perfect combustion result and proper atmosphere, with good temperature control accuracy.
2.2.3 Walking beam system and water sealed slot
Walking beam system consists of fixed beam, movable beam, hydraulic system and water sealing system.
Fixed beam is divided into center fixed beam and side fixed beam. Center fixed beam
consists of two 1000mm width beams, two fixed beams are designed at each side of furnace hearth. Soaking zone and heating zone fixed beam consists of heat Steel
(ZGCr28Ni48), high alumina quality casting material and insulation light casting material, structure and water cooling system. Preheating zone fixed beam consists of heat steel(ZGCr25Ni35), high alumina quality castables and insulation light castables, steel structure and water cooling system.
3 pieces of walking beams are located in furnace hearth, each width is 500mm, length 14000mm. Walking Beam mainly consists of heat-resistant steel(ZGCr28Ni48), high alumina quality castables, steel structure, and water cooling system. Bottom of this beams are jointed with structure in one. Walking Beam device consists of 2 upward cylinders, 2 horizontal moving cylinders, travel switch and bottom supporting block. The cycle of walking beam operating is: upward, forward, downward, and backward move). Through walking beam mechanism movements, slab is transferred from entrance into hearth for heating and to the exit, movements is smooth, reliable, simple and practical.
Slab with 4000 to 4500mm length, 420mm width can be automatic heated in side of furnace hearth. And for different width of slab, just need adjustment of setting of transistor approach switching.
Walking beams and bottom fixed beam is made of high alumina castables, and
equipped with heat-resistant steel supporting beam, work temperature is 1100 ºC. The upper and lower surface of supporting beam is produced by mechanical processing, assuring slab reliability of operating.
In order to prevent the deformation and prolong service life of beams, all walking-beam and fixed-beam and side beam are equipped with water cooling channels.
At the bottom of each beam is equipped with two Water Seal blades (1Cr13), nearly 14- meter-long Water Seal Blades are inserted in a narrow water trought, walking beam in any state, the furnace and basement furnace are isolated, assuring hearth tightness and favor of reducing heat loss while hearth pressure adjustment.
Water seal device is main component of walking beam. Main function: effectively solve the sealing problem of bottom and furnace. Both entrance and exit of vertical sealing out furnace door is equipped with horizontal and vertical sealing device, form a complete seal ring. The cooling water use cycle water, automatic overflow.(This part of overflow water is a natural return-water; way of settle drainage pattern need plant design)
2.2.4 Surplus heat utilization device
In order to take full advantage of the surplus heat utilization, at the entrance of upper
furnace install one set of tube type heat exchanger, it's feature is small size, high-efficiency heat exchanging. Wind from combustion fan go through tube ware to take surplus heat from flue gas, then to each combustion air pipe for air preheat temperature ( When flue gas temperature is 600 ~ 700 ° C) is reach to 250~450 ° C, saving fuel, increasing combustion flame temperature, further enhance the slab heating rate, improving energy efficiency of the equipment.
Loading device is composed of centering device, walking beam mechanism, measure device. Loading device of furnace should store 3 slabs. Centering device consists of centering clamping cylinder, centering lifting cylinder, roller table and drive unit, encoder, photoelectric switches and travel switch, Its main function is: after slab moving to roller table, PLC process control automatic finish material measuring (measure unloading material length, width, thickness) and centering.
* Transmission roller speed: 0.15m/sec
* Lifting roller Speed: 0.1m/sec (hydraulic)
* Small walking beam consists of walking beam, store structure, 2 hydraulic cylinder, travel switch. Function is: put slab step into the furnace waiting station, waking stroke is 1000mm.
2.2.6 Unloading device
Pattern of discharging is side exit out, it consists of inner discharge roller and many outer transfer roller which is placed at furnace side. When require unloading, walking beam upward moving, slab will be delivered to inner discharge roller; furnace door open, walking beam downward move, slab is loaded on the discharge roller (or call it as cantilever roller). Discharge roller transfers slab out of furnace chamber and slab is delivered to outer roller.
2.2.7 In order to better control the furnace atmosphere, zirconia oxygen measurement device is installed in the preheating zone. Operators can check whether the furnace atmosphere meat heating products requirements or not. According to the measured data, automatic or manually complete air-fuel ratio, thus to control furnace atmosphere.
2.2.8 Furnace door and lifting device
It mainly consists of furnace door, lifting device, limit device and water cooling system.
Furnace door shell is welded with steel plate and steel structure, inside lining is made of refractory fiber and inner refectory lining is made of steel fiber castables. Furnace door is drive by motor, reducer, transmission, chain, and the drive gear, 2 furnace door clamping cylinder connect the sealing blade on the furnace door with sealing ring (aluminum material fiber woven belt ), assuring furnace good air-tightness. End of the chain fixed with sprocket wheel, furnace door downward move depend on its deadweight. Movements of furnace door is controlled by PLC. Furnace Door and structure use water cooling structure, preventing deformation of the structure, effectively assuring hermetic, Furnace Door lifting speed: ~ 0.02m/s/0.16m / s. And furnace is equipped with ladder, maintenance table and maintenance platform and fence.