Liquid-control back flushing condensation dryer

The invention discloses a liquid-control back flushing condensation dryer which comprises a dryer body, a drying cylinder and a condensation bucket main body, wherein a liquid-control time delayer ismounted on the dryer main body; the liquid-control time delayer comprises a time delayer body, a valve rod, a liquid-control piston, a pneumatic piston and a stop valve spring; a sealing cavity is formed in the time delayer body; the liquid-control piston is arranged in the sealing cavity; the pneumatic piston is arranged in the time delayer body in a sliding and sealed manner and is used for partitioning the time delayer body into a first part and a second part; the sealing cavity is positioned at the first part; a moveable cavity is formed in the first part and close to one side of the pneumatic piston; a pneumatic cavity and a stop cavity are formed in the second part; the pneumatic cavity and the moveable cavity are respectively formed in both sides of the pneumatic piston; the pneumatic cavity communicates wi