Control of a Dual Vapor, Vapor Phase Solder System
Original Publication Date: 1987-Aug-01
Included in the Prior Art Database: 2005-Feb-01
Vapor phase soldering systems typically utilize two vapors for operation. The primary vapor, usually produced by a dense, inert fluid which boils above the melting point of the solder to be reflowed, and the secondary vapor, typically trichlorotrifluoroethane, which is less dense and has a lower boiling point than the primary vapor, yet is more dense than air. Banks of cooling coils provide a means of containing these vapors in a vapor sump. Two sets of coils are used, one for each vapor. In addition to the primary cooling coils, the secondary vapor serves as a "blanket" to help contain the primary vapor in the system, thus preventing the primary vapor from escaping to the atmosphere.