Ring-type fan and impeller structure thereof

摘要

A ring-type fan includes a frame having a receiving space defined between an air inlet and an air outlet thereof and being provided along an inner side of the air outlet with an inward projected wall portion; an impeller assembly rotatably mounted in the receiving space and including spaced impellers outward extended from a hub, and a ring member connected to radially outer ends of the impellers and externally provided with a circle of stop section, which and the projected wall portion together define an air passage between them; and at least one pressure relief section defining an airflow guide on the frame to communicate with the receiving space and the air passage. Any backflow can be guided out of the frame via the air passage and the pressure relief section without interfering with the inflow of air, allowing the ring-type fan to have upgraded heat dissipation performance.

主权项

1. A ring-type fan, comprising:
a frame having an air inlet and an opposite air outlet, and internally defining a receiving space between the air inlet and the air outlet; the frame being provided along an inner side of the air outlet with at least one inward projected wall portion; the projected wall portion including a first projected section and a second projected section; the first projected section being obliquely projected from the inner side of the air outlet toward the air inlet of the frame; and the second projected section being integrally formed with and forwardly extended from a front end of the first projected section; an impeller assembly being rotatably mounted in the receiving space and connected to the frame; the impeller assembly including a hub, a plurality of impellers outward extended from and spaced around the hub, and a ring member connected to radially outer ends of the impellers; the ring member having a top edge corresponding to the air inlet and a bottom edge corresponding to the air outlet; the top edge and the bottom edge being respectively provided with a flared flange and a stop section, wherein the stop section accommodates the second projected section such that together they define an air passage between them; and at least one pressure relief section provided on and extended through a peripheral wall of the frame to define an airflow guide thereat, and the airflow guide communicating with the receiving space and the air passage; wherein the frame is further provided around an inner side of the air inlet with an inclined flange portion, located radially inside the flared flange, which radially inwardly extends toward a central area of the receiving space; and a clearance is formed between the flared flange and the inclined flange portion.