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HMR Hydeq’s Integrated
Tapping System |
Crane + crucible + trailers |
| Operating cycle |
Usually the crucible stays in the Tapping Truck (TT) at all times. Removing only for cleaning and maintenance, at which times it is picked up by the vehicle without the use of additional equipment or manning. |
New clean crucible is loaded on the trailer with crane and use of manpower |
| Cast house calls for metal: information can be directly broadcasted to TT driver . |
Driver of towing tractor takes the trailer with crucible in the potroom |
| TT has information of pots to be tapped, gets position and taps metal. The truck is equipped with on board compressor, no connection to compressed air is necessary. The weighing system automatically stops when required amount is reached. Automatic stop when crucible is full to prevent overfilling |
Crucible is covered with lid, lifted with crane, compressed air hose is connected, metal is tapped. The stop is given by potroom personnel watching on the scale. The accuracy is related to the ability of the operator |
| Once crucible is full TT comes back to cast house directly, without dedrossing. |
Crucible is opened for dedrossing |
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Open crucible is loaded on trailer and waits for transport and/or furnace availability, metal temperature drops down |
| Metal is discharged into the furnace by onboard siphon of TT. No additional equipments are necessary. Active suspensions can tilt vehicle to optimize discharging efficiency |
Metal is siphoned in cast house. Low metal temperature cause risks of siphon blocking |
| Folowing the several rounds the TT goes to crucible cleaning station, waits for cleaning and comes back in operation |
Crucible is brought to cleaning station with trailer. Usually it is tilted with some equipment and linked manually to the station |
| Safety during transport |
Crucible is always safely closed by the lid |
Transport of open crucibles with no lids. Risks of metal spillage |
| Oxidation. Metal loss |
Oxidation and metal loss is minimized since metal is always in a closed container |
Skimming on open crucible, transport and often pouring off on transfer crucibles leave metal in contact with air |
| Dedrossing |
Adjustable aspirating action of TT reduces the presence of dross at the very beginning. Lighter dross remains above metal on the crucible and is not poured into the cast house. It remains on the crucible and it will be discharged on cleaning station. Dross amount is taken into account by the electronic system |
Risks for safety during lids removal after tapping, for skimming. Gases are released in atmosphere |
| Tapping precision |
Weighing system is built in the vehicle. Accuracy is better than 1% on metal weight |
Weighing system is less controllable. Usual accuracy is around 2% or higher |
| Temperature loss |
Metal always remains inside closed crucible. Cycle time is short. Temperature drop is minimal |
Crucible remains often open for long time. Temperature can drop from 900 to 700°C. We can calculate approximately a loss of 30 Nm3 of natural gas to bring temperature back to this levels in a 5000 kg mass of aluminium |
| Use of overhead crane |
No use at all. Crane can be reserved for other activities |
Intensive use of overhead crane. Maintenance problems |
| Crucible cleaning |
The system uses cleaning equipment integrated with the tapping truck so that no additional devices or manpower is required. The driver takes the truck to the crucible cleaning station, residue hot metal can be poured in two pens prior to the fully automatic cleaning cycle |
Since cleaning stations are not integrated with the transport system, lifting or other telting and securings devices are required, involving man power input |
| Pollution. Gases released on the air |
Crucible is always closed: during tapping and pouring |
Crucible is open during skimming and remains open during transport |
| Risks due to metal spillage |
Crucible is closed. No risks |
Crucible open. Risk is higher |
| Manpower |
One driver controls all the process |
Required: two man in potroom for tapping and skimming. One man for towing tractor, two men in cast house for metal pouring |
| Process control |
Driver gets information via radio directly from process manager and taps and delivers the metal quickly |
Crucibles tapped in the potroom are transported to the cast house when cold. This system is less controlled and can result in reduced melt temperature when arriving at cast house furnices |
| Operator job site |
Driver works all the time in a safe, air conditioned cabin with filtration system |
Potroom operators and often forklift drivers are exposed to a polluted environment |
