Mechanical Pump Systems
Mechanical pump systems are designed for circulating molten aluminium inside a furnace and transferring liquid aluminium from a furnace to furnace or transfer ladle.
Mechanical pumps for molten metal are classified in three different types: circulation, gas injection and transfer. Each pump type is manufactured in several sizes based on specific customer needs with respect to the existing furnaces holding capacities, melting rates, and molten metal transfer rates.
These pumps are designed to circulate molten metal in reverberatory and stack melter furnaces. Circulation of molten metal takes place by underneath currents that do not cause damage (rupture) to the molten top surface of the bath. The most important purpose for these pumps is to provide forced convectional heat transfer in the molten bath. An additional important function is to provide mass circulation to facilitate alloy metallurgical homogenization.
Gas-injection Circulation Pumps
These types of pumps also operate under the same principles of standard circulation pumps. In addition to providing the same benefits, they offer an added capability to inject inert and/or reactive gases for the purposes of degassing, removing alkali metals, magnesium removal (demagging), and floating inclusions out.
Eventually, after the aluminium alloy has been melted in the melting furnace, it needs to be transferred and/or delivered to the next operation within the casting process. With the transfer technique of using a transfer pump, the pump remains in the furnace well and is activated whenever metal delivery is required. Liquid metal is pumped above the liquid metal line of the furnace for discharging to the end use point. Transfer pumps can be classified in two groups: conventional and overflow pumps. Main benefits of transfer pumps as compared to transferring techniques using tap blocks or tilting furnaces may include:
- Cleaner molten metal
- Faster transfer times
- Lower molten metal temperature loss
- Better safety
- Lower capital costs
Pyrotek's industry-leading overflow transfer system (OTS) technology raises the metal by gently moving it vertically from within a transfer bowl, and with an (optional) integrated lightweight reinforced fibreglass material (RFM®) trough can deliver the metal to the required end location. The OTS provides verifiable metal quality improvements, and tests have shown that Pyrotek's OTS generates half the amount of dross compared to traditional transfer pump systems.
The RFM overflow pump is designed to gently raise and transfer molten metal from small crucibles or melting and holding furnaces. Its compact size allows it to be transported from one vessel to another, and its RFM bowl allows for quick placement due to minimal preheat requirements. The pump’s architecture follows the technology of Pyrotek’s stationary OTS. The pump reduces dross formation during the transfer process and its pump action can quickly empty a crucible.
Pyrotek offers a full line of conventional circulation and transfer pump systems (including gas injection systems) for molten metal applications, such as the J, M, S and D-series pumps. Ceramic and steel Tensor pumps enhance reliability and by working with Pyrotek experts, mechanical pump systems are optimized and designed with greater rigidity, durability, and strength to meet the most stringent performance requirements.
- Reduced dross formation and fuel consumption
- Increased melting rate
- Easier alloy production
- Improved temperature uniformity and alloy homogeneity
- Improved refractory life and safety