66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 9 Heat Transfer 9 Figure 10-3. Typical heads and closures. Figure 10-4A(1). Double-pipe longitudinal Twin G-Finned exchanger. (Used by permission: Griscom-Russell Co./Ecolaire Corp., Easton, PA, Bul. 7600.)