Pre-industrial
Iron Symposium October
10, 2004 Experiment Notes - Viking Age Smelter
Bellows :
Michael Mahoney
Millard
Wyman
Paul
Bourdon
Recorder : Elizabeth Hendrix
Leader : Darrell Markewitz
TIME EVENT MEASUREMENT
Realative
Absolute
Elapsed Relative Absolute Total
2:00
pm slow
preheat with split soft wood fire
3:45 1:45 prep
of bellows (attached to tuyere)
3:50 1:50 start
of bellows, split soft wood - various users +/
- 60 /min
120 l/min
4:17 2:17 end
of pre-heat phase
4:17 fill
furnace with prepared charcoal air : 60/min
130 l/min
fuel: 60 cm 36900
cc 37
l
4:32 0:15 15
min add charcoal air : 60/ min
130 l/min
fuel : 10 cm 6150 cc 43
l
4:37 17
min bellows
operator changed
4:42 0:25 optical
pyrometer reading
2720 F
4:44 0:27 12
min add charcoal fuel : 10 cm
6150 cc 49
l
4:48 0:31 air
rate measured air : 72 /min 160
l/min
4:53 16
min bellows
operator changed
4:57 0:40 13
min add charcoal fuel : 10 cm
6150 cc 55
l
4:59 6
min bellows
operator changed air : 54 /min 120
l/min
5:07 8
min bellows
operator changed
5:11 4
min bellows
operator changed
5:16 5
min bellows
operator changed air : 60 /min
130 l/min
0:59 19
min add charcoal fuel : 10 cm
6150 cc 61
l
5:29 13
min bellows
operator changed air : 72 /min
160 l/min
5:32 1:15 ore
charge (one) ore :
1.5 kg 1.5
kg
16
min charcoal
charge on top fuel : 5 cm
3075 cc 64
l
5:41 13
min bellows
operator changed
5:42 1:25 optical
pyrometer reading
2660 F
5:44 crack
in smelter wall patched
5:47 1:30 15
min ore charge
(two) ore :
1.5 kg 3.0
kg
charcoal charge on top fuel
: 5 cm
3075 cc 67
l
5:53 tuyere
blocked / cleared with rod
6:01 1:43 14
min ore charge (three)
on rear half only ore :
1.5 kg 4.5
kg
charcoal charge on top fuel
: 5 cm
3075 cc 70
l
20
min change of
bellows operator
6:05 tuyere
blocked / cleared with rod
6:06 increase
of bellows delivery pressure air : 72 /min
160 l/min
6:11 6
min change
of bellows operator
tuyere blocked / cleared with rod
6:15 1:57 13
min ore charge (four)
on rear half only ore :
1.5 kg 6.0
kg
charcoal charge on top fuel
: 5 cm
3075 cc 73
l
air : 60 /min
130 l/min
6:18 larger
crack in furnace repaired
6:23 5
min bellows
resumed
6:26 15
min change of
bellows operator
6:27 optical
pyrometer reading
2200 F
6:29 tuyere
blocked / cleared with rod
6:32 2:14 17
min ore charge (five)
on rear half only ore :
1.5 kg 7.5
kg
charcoal charge on top fuel
: 7.5 cm
4610 cc 77.6
l
6:44 18
min change of
bellows operator
6:46 2:28 14
min charcoal
charge added fuel : 7.5 cm
4610 cc 82.2
l
6:50 6
min change
of bellows operator air : 72 /min
160 l/min
6:55 5
min change
of bellows operator
6:58 2:40 14
min charcoal
charge added fuel : 10 cm
6150 cc 88.2
l
7:04 optical
pyrometer reading
2680 F
7:12 2:54 14
min charcoal
charge added fuel : 7.5 cm
4610 cc 92.8
l
7:20
25
min change of
bellows operator
7:24 4
min change
of bellows operator
3:06 12
min charcoal
charge added fuel : 5 cm
3075 cc 95.8
l
7:29 repair
of crack in smelter
7:30 3:12 6 min ore charge
(reduction fines) added ore :
.5 kg (350 ml) 8 kg
fuel : 5 cm
3075 cc 98.8
l
7:40 slowing
of bellows rate during repair
7:50 26
min change of
bellows operator,
rate continues slow
7:53 3:35 17 min final charcoal charge
added fuel : 5 cm
3075 cc 102 l
8:15 25
min change of
bellows operator, rate continues slow
8:25 10
min change of
bellows operator,
rate continues slow
8:40 4:05 end
of firing
8:40 start
scooping remaining charcoal from smelter
8:45 4:10 5 min bloom /
slag bowl exposed
8:54 4:19 9 min bloom /
slag mass extracted from smelter
AIR : Calculated
against earlier measurement to fixed volume / note variation by operator 2.2
l per stroke (average)
FUEL : Calculated
by height at fixed furnace dimension of 28 cm diameter 615
cc per cm
ORE : Total
of 17.5 lbs / 8 kg roasted ore was prepared / charges estimated individually
by volume 1.5 kg per charge
Patching : Each time a hole / crack was patched, the
bellows was stopped for the time required, typically about 2 - 3 minutes
Clearing : Each time the tuyere was cleared,
the bellows was stopped for the time required, typically about 1 - 2 minutes
Operator : There were a number of people who assisted in bellows operation, especially during the pre-heat phases. There was considerable variation in rate, loft and pressure between these. Typically these are represented by the short bellows operator times. From the begining of the ore charge phase, the three primary operators rotated, delivering a much more consistant and controled rate / loft / pressure.