Reflow oven

1 . A reflow oven capable of working in an inert gas mode and in an air mode, comprising:

a soldering section, the soldering section being configured to treat a circuit board to be soldered, the soldering section being provided with N soldering sub-zones, the soldering section comprising a heating zone and a cooling zone, the heating zone comprising a plurality of the N soldering sub-zones, and the cooling zone comprising one of the N soldering sub-zones;

an inlet zone and an outlet zone, the inlet zone and the outlet zone being respectively provided at two ends of the soldering section;

a first inlet zone isolation duct in communication with an upper side or a lower side of the inlet zone;

a purification section, the purification section comprising M purification sub-zones, wherein each of the N soldering sub-zones in the heating zone is in communication with a different one of the M purification sub-zones;

a controllable discharge pipeline and K discharge branch pipes, each of the K discharge branch pipes communicating one of the M purification sub-zones with the controllable discharge pipeline, wherein K is less than or equal to M;

a valve device configured to, at the inlet of the valve device, connect with an outlet of the controllable discharge pipeline to control open/close of the communication between the controllable discharge pipeline and the external environment, wherein a first end of the first inlet zone isolation duct is in communication with a communication port of the inlet zone, and a second end of the first inlet zone isolation duct is in communication with the one soldering sub-zone of the cooling zone; and

a gas accelerating device configured to supply a gas flow from the one soldering sub-zone of the cooling zone to the inlet zone from the second end of the first inlet zone isolation duct to the first end the first inlet zone isolation duct through the first inlet zone isolation duct.

2 . The reflow oven of claim 1 , wherein

the reflow oven works in the air mode when the valve device is opened; and

the reflow oven works in the inert gas mode when the valve device is closed.

3 . The reflow oven of claim 2 , wherein an outlet of the valve device is in communication with a ventilation device.

4 . The reflow oven of claim 1 , further comprising:

a pair of inlet zone isolation ducts including the first inlet zone isolation duct and a second inlet zone isolation duct, the pair of inlet zone isolation ducts being respectively in communication with the upper side and the lower side of the inlet zone; and

a pair of outlet zone isolation ducts, the pair of outlet zone isolation ducts being respectively in communication with an upper side and a lower side of the outlet zone.

5 . The reflow oven of claim 4 , wherein each of the first end of the first inlet zone isolation duct and a first end of the second inlet zone isolation duct is in communication with a different one of the upper side and the lower side of the inlet zone, and a second end of the second inlet zone isolation duct is in communication with the controllable discharge pipeline.

6 . The reflow oven of claim 1 , wherein each of the N soldering sub-zones comprises a flow guide device capable of guiding part of gas in the soldering sub-zone to flow toward a corresponding one of the M purification sub-zones.

7 . The reflow oven of claim 1 , wherein each of the M purification sub-zones comprises a catalytic device and a heating device, and the heating device has a catalytic work mode and a maintenance work mode.

8 . The reflow oven of claim 1 , wherein:

when the valve device is opened, the reflow oven is configured to pull air into the reflow oven via a hearth inlet adjacent the inlet zone and pull air into the reflow oven via a hearth outlet adjacent the outlet zone; and

when the valve device is closed, the reflow oven is configured to prevent air from flowing into the reflow oven via gas curtains formed by gas flows from the inlet zone and the outlet zone.