Smoke return prevention one-way air door for condensation type gas-fired boiler

The utility model relates to a smoke return prevention one-way air door for a condensation type gas-fired boiler, which comprises an air door plate, a smoke return prevention device, a smoke return prevention device and a smoke return prevention device, an air outlet of the fan is connected with the rotating shaft at the end of the air door plate, the air door plate covers the air outlet of the fan in a matched mode, and the air door plate can rotate through the rotating shaft. The situation that when a single boiler is shut down, especially when a plurality of boilers are connected in parallel, and some boilers are shut down, smoke, steam and water in a boiler combustion chamber flue enter a fan, a venturi, a gas valve set, a wind pressure switch and a component connecting pipeline system of the boilers is effectively avoided. 本实用新型涉及一种用于冷凝式燃气锅炉防返烟单向风门，包括：风门板，为板体结构，一端的端部设置转轴，转轴上套接复位弹簧；风机，风机的出风口位置与风门板的端部的转轴连接，风门板配合覆盖在风机的出风口的位置，风门板能够通过转轴进行旋转。有效避免了单台锅炉停机尤其是多台锅炉并联其中有锅炉停机时，锅炉燃烧室烟道内烟汽水蒸汽串入到锅炉的风机、文丘里、燃气阀组、风压开关及部件连接