Ring fan and shroud air guide system

#The present invention relates generally to a ring fan and shroud assembly and more particularly to a ring fan and shroud assembly with improved air flow characteristics.

#Axial type fans move air, or other fluids, using rotating impeller blades. As the impeller blades rotate, different pressures on opposite sides of the blades are developed. The discharge sides of the impeller blades typically develop a high pressure while the intake sides develop a low pressure. The pressure differential between these two sides causes the fluid to flow from the high-pressure discharge side to the low-pressure intake side near the tips of the impeller blades creating an undesirable back flow of some of the fluid flow passing through the fan. It is well-known that this backflow can decrease the efficiency of the fan and may lead to undesirable noise generation.

#Engine cooling fans develop static pressure across the fan such that the regions ahead of the fan are at significantly lower pressure than regions behind the fan. Many engine cooling fans have cowlings or shrouds positioned circumferentially around them in order to assist in directing the air flow in the desired direction. Practical operation of fans used in motor vehicle cooling systems dictate minimum clearances between the rotating fan members and stationary shroud members in order to ensure safe, durable functioning throughout the life of the vehicle.

#FIG. 1 is a schematic view of a vehicle engine having a cooling system according to a preferred embodiment of the present invention.

#FIG. 2 illustrates a fan assembly in accordance with a preferred embodiment of the present invention.

#FIG. 3 illustrates a shroud member in accordance with a preferred embodiment of the present invention.

#FIG. 1 illustrates a ring fan and shroud guide system 10 in accordance with the present invention. Although it is contemplated that the ring fan and shroud guide assembly 10 can be used in a variety of applications, the system 10 in one preferred embodiment is intended for use in a cooling system for an engine 11. Specifically, the preferred embodiment of the present invention is intended for use in conjunction with a radiator cooling system in a truck or large vehicle. It is to be understood, however, that the present invention can be used in many applications, and the invention is not to be limited only to trucks or other vehicles.

#The fan member 15 has a central hub member 13 and a plurality of blade members 12 (also called “impeller” members). A circumferential ring member 14 is positioned at and connected to the ends (or tips) of the blade members. The use of impeller blades and a rotating ring element to form a fan assembly is well known in the art, and these fan assemblies are commonly referred to as ring fans.

#Also, although in the preferred embodiments, the ring fan is a solid complete annular ring member and is positioned at the tips of the blades, it is also possible that the ring member can be discontinuous with gaps between the blades or have openings in the ring itself, or that the ring member (or discontinuous portions thereof) can be positioned radially inwardly slightly from the ends of the blades.