Slim fan

Abstract

A slim fan includes a casing, a fan module and a ring cover. The casing includes an upper casing which has an opening, and a lower casing. The fan module includes a plurality of fans annularly disposed in the opening, and each of the fans has a first side and a second side opposite to each other. The ring cover is connected to the first side of the fans and exposed out of the opening. The height of the fans is equal to that between the upper casing and the lower casing.

What is claimed is: 
     
         1 . A slim fan, comprising:
 a casing including an upper casing and a lower casing, wherein the upper casing has an opening;   a fan module including a plurality of fans, wherein the fans are annularly disposed in the opening, and each of the fans has a first side and a second side opposite to each other; and   a ring cover connected to the first side of the fans and exposed out of the opening;   wherein the height of each of the fans equals to the height between the upper casing and the lower casing.   
     
     
         2 . The slim fan according to  claim 1 , wherein a first leakproof part is extended from the ring cover towards the fan, and the first leakproof part has a curved surface or an inclined plane. 
     
     
         3 . The slim fan according to  claim 2 , wherein the first leakproof part is annular. 
     
     
         4 . The slim fan according to  claim 1 , wherein an inner space is between the upper casing and the lower casing and is connected to the opening, and a second leakproof part is extended from the position of at least one of the upper casing and the lower casing near the ring cover and is extended towards the inner space. 
     
     
         5 . The slim fan according to  claim 4 , wherein the second leakproof part is annular. 
     
     
         6 . The slim fan according to  claim 1 , wherein the slim fan further includes a leakproof film fixed on the casing or the ring cover, a gap is formed between the casing and the ring cover, and the leakproof film covers the gap. 
     
     
         7 . The slim fan according to  claim 6 , wherein the leakproof film is annular. 
     
     
         8 . The slim fan according to  claim 1 , wherein the fan module further includes a hub, the fans are disposed around the hub, and height of the hub and the fans equals to height between the upper casing and the lower casing. 
     
     
         9 . The slim fan according to  claim 1 , wherein the casing includes a fastening cover, the lower casing has a hole, the fastening cover covers the hole and bridges over the lower casing, and a part of the fan module is exposed out of the hole. 
     
     
         10 . The slim fan according to  claim 1 , wherein the fan module and the ring cover are integratedly formed.