Adjustable nozzle of stannic furnace

The present invention relates to a nozzle of a stannic furnace which is applied in tin soldering of circuit boards, more particularly, to an adjustable nozzle of a stannic furnace, the caliber of which can be modified. An adjustable nozzle of a stannic furnace comprises a nozzle tank which is mounted at the upper portion of a stannic tank of the stannic furnace, a front backflow stopper and a rear backflow stopper which are respectively mounted at the forward area and the backward area inside the nozzle tank to form an opening of the nozzle such that a liquid tin within the stannic tank passes through the nozzle tank and produces a tin wave at the opening of the nozzle. The feature of the adjustable nozzle lies in that the rear backflow stopper is mounted at the backward area inside the nozzle tank by means of a rear combining means which adjusts the altitude of the rear backflow stopper with an altitudinal opening and fixes the rear backflow stopper by a fixing means so as to control the waveform of the tin wave produced by the nozzle of the stannic furnace.