melt cycle functions such as slagging, chemistry analysis and charging. Simi- lar to System 4, this system maintains demand at 3,000 kW, but has a power supply utilization of 100%. It can pour 6.5 tons per hour with an increased power density up to 750 kW per ton. The five different melting
systems all produce between six
and seven tons per hour. However, as seen in Fig. 3, System 1’s kW demand was 40% higher than Sys- tem 5 because of decreased utiliza- tion, efficiency and performance. As power utilization increases, the kW demand required for the same amount of production decreases, leading to cost savings. In this case,
because System 5 uses 40% less demand, costs will decrease by 40%. Another way to view this is by examining the cost per ton poured. Fig. 4 shows the paid demand divided by the amount of metal poured. With a hypothetical value of $10/kW of demand, System 1 paid $22.89 per ton while Systems 4 and 5 paid near $14/ton. It’s clear the batch melting systems have a substantial competitive advantage over the other systems using older or less efficient technology.
System-Wide Improvements Other areas within a melt system
can be considered to reduce demand and optimize an operation. All of these areas can help increase the utili- zation of your melt system: Routine Maintenance: Check
and recheck your system to optimize performance. Power Transmission Controls: Maintain power transmission systems, including clean and secure termina- tions and connections and properly configured furnace power leads. Furnace Covers: Keep the furnace
lid closed whenever possible through- out the melt cycle to reduce radiant heat loss. Clean & Dry Scrap: Use clean and
dry scrap to reduce energy consump- tion. Materials such as dust, dirt, rust and slag absorb energy and decrease melting efficiency. Proper Charging/Filling: Don’t
over charge or overflow the furnace. Furnaces are most efficient when oper- ated at their design capacity. Proper Lining Dimensions: Maintain lining dimensions per OEM specifications. Although the thick lining may reduce the lining cost per ton, it may not outweigh the cost of operating a less efficient furnace. Control Fume Collection Flow:
Ensure the fume collection system is effective without taking energy from the furnace and increasing thermal heat loss.
Heat Recovery Systems: Utilize
heat recovery systems, such as air handlers, to put energy back into the facility to recirculate warm air. Maximizing the melt system’s production at its lowest level of
50 | MODERN CASTING February 2015
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76