Abstract: Reflow solder oven gas management system introduces an inert gas into and removes contaminated gas from a reflow oven tunnel (42) at predetermined points (6, 8) to influence the oven tunnel gas flow and to dilute and expel excess oxygen. The contaminated gas is ducted to a flux separation system (34) to be cleaned, for example remove flux vapors, and returned in part to the tunnel (42) for recirculation and with the remainder routed to end baffle boxes (54) for tunnel end pressurization and exhaust. The system has sufficient pressure to supply end baffle boxes (54) with clean gas to create a gas barrier to effectively seal off the tunnel ends from air infiltration or migration into the tunnel making the system insensitive to external pressure and/or temperature variations. The invention also includes alternative embodiments, low flow oxygen bleed valves (72) to maintain low oxygen content in the oven process tunnel.

Abstract: Reflow solder oven gas management system introduces an inert gas into and removes contaminated gas from a reflow oven tunnel (42) at predetermined points (6, 8) to influence the oven tunnel gas flow and to dilute and expel excess oxygen. The contaminated gas is ducted to a flux separation system (34) to be cleaned, for example remove flux vapors, and returned in part to the tunnel (42) for recirculation and with the remainder routed to end baffle boxes (54) for tunnel end pressurization and exhaust. The system has sufficient pressure to supply end baffle boxes (54) with clean gas to create a gas barrier to effectively seal off the tunnel ends from air infiltration or migration into the tunnel making the system insensitive to external pressure and/or temperature variations. The invention also includes alternative embodiments, low flow oxygen bleed valves (72) to maintain low oxygen content in the oven process tunnel.

Abstract: A flux vapor management system for a reflow oven includes temperature control units disposed in heating and cooling regions of the oven. A fan within each of the temperature control units provides suction to an intake port. Intake ports of selected temperature control units in the heating region of the oven are connected with a barrier vent disposed between the heating and cooling regions of the oven. Gas drawn into the barrier vent by the suction from the intake ports prevents flux laden gas from migrating into the cooling region. The flux vapor management system also includes a filter for removing flux vapors from a reflow oven. The filter condenses flux vapors by converging a jet of hot gas from the oven with a cooled gas jet causing the flux vapors to condense while suspended in the gas stream. The flux laden gas does not contact any solid surface below the flux condensation temperature so there is no build-up of flux within the apparatus.

Abstract: Apparatus for soldering surface mounted devices to printed circuit boards utilizing a combination of forced convection and infrared radiation. Fans are disposed in each heating zone which force gas through a heating plate which heats the air, emits infrared radiation for heating of printed circuit boards, and establishes a flow pattern for the gas. Flows are controlled in each zone by selectively introducing unheated gas into each zone, and by selectively exhausting gas from each zone. The volume of gas introduced and exhausted from each zone can be controlled. Closures are provided in the return channels to the low pressure side of the fan for controlling the volume of gas recirculated from the conveyor. Flow is controlled such that cooler air is always introduced into the zones which have a lower temperature and is exhausted from zones which have higher temperatures.

Abstract: Apparatus for soldering surface mounted devices to printed circuit boards utilizing a combination of forced convection and infrared radiation. Fans are disposed in each heating zone which force gas through a heating plate which heats the air, emits infrared radiation for heating of printed circuit boards, and establishes a flow pattern for the gas. Flows are controlled in each zone by selectively introducing unheated gas into each zone, and by selectively exhausting gas from each zone. The volume of gas introduced and exhausted from each zone can be controlled. Closures are provided in the return channels to the low pressure side of the fan for controlling the volume of gas recirculated from the conveyor. Flow is controlled such that cooler air is always introduced into the zones which have a lower temperature and is exhausted from zones which have higher temperatures.