Flat centrifugal jet fan

The invention relates to a flat centrifugal jet fan. The flat centrifugal jet fan is especially suitable for ventilating and fire fighting accesses of underground garages. The flat centrifugal jet fan comprises a case, a fan installation support, a centrifugal impeller, an air inlet Venturi tube, a motor, a motor installation support, a protection cover and a junction box. The case is a flat box assembly of an up-down structure, flat box structures with a downward air suction port and a horizontal air discharge port are adopted, the motor installation support is fixed to the lower side of the up-down flat box assembly, the fan installation support and the junction box are fixed to the flat box assembly, the protection cover is fixed to the lower side of the flat box assembly through bolts, and the impeller and the motor are concealed in the box. Compared with a traditional inducing fan or mixed-flow fan for underground garages, the flat centrifugal jet fan has the advantages of being high in efficiency, large in air volume, long in range, low in noise, compact in structure, convenient to install and maintain and the like, the problems of limited storey height of underground garages and low smoke discharge efficiency can be well solved, and then the purposes of saving energy and reducing investment are achieved.