Fluid reaction surfaces (i.e. – impellers) – Rotor having flow confining or deflecting web – shroud or... – Radially extending web or end plate
Patent
1998-06-08
2000-03-21
Look, Edward K.
Fluid reaction surfaces (i.e., impellers)
Rotor having flow confining or deflecting web, shroud or...
Radially extending web or end plate
416189, 416192, 416223B, 415119, B63H 128
Patent
active
060395397
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention refers to a radial fan wheel comprising a number of fan blades symmetrically arranged with substantially equal spacing around the rotational shaft of the fan wheel, said blades being mounted between two perpendicular to said shaft arranged end plates and being provided with surfaces which are substantially parallel with said shaft and each of which extends from one point at a distance from said shaft and substantially arched in the direction out to the periphery of the wheel, wherein one end plate is provided with a central air inlet.
BACKGROUND OF THE INVENTION
Fans are used as means for driving air through ventilation systems. Efficiency and a low level of noise are requirements upon fans. The most common type of fans in the field of ventilation, are double suction radial fans. They have a high degree of efficiency but the level of noise requires subsequent silencers. A problem with double suction radial fans, is that the outlet velocity is high and uneven. This makes it impossible to place subsequent silencers immediately in connection to the fan. In recent time, chamber fans which is an old design, has come back to the market. They have the advantage that they provide a flow having a low and fairly even velocity. The fan is compact and a silencer may be placed closer to the fan. The lower maximum degree of efficiency for a chamber fan is compensated by the lower velocity and the accompanying lower pressure losses, so that for high flows, chamber fans obtains higher efficiency than double suction radial fans.
Fans are the cause of low frequency noise which is difficult to muffle. It is true that the level of noise in a ventilation system may be reduced by the use of silencers. However, this is a space consuming and expensive solution of the problem.
The primary sound source in a chamber fan is the fan wheel, which for example generates noise in the frequency range 50-300 Hz. The periphery of the fan wheel is preferably symmetrically shaped with blade edges extending substantially in parallel with the rotation shaft of the wheel. The blades are located between two lateral to said shaft arranged, mutually substantially parallel end plates. The generation of noise is predominantly caused by turbulence being created when the air is pressed radially out of the wheel by the rotation of the blades, and then is brought to flow on, e.g. axially, by the design of the chamber walls.
THE TECHNICAL PROBLEM
One object of the present invention is therefore to provide a fan wheel which reduces the generation of noise in a fan, with preserved efficiency, alternatively enabling an increased efficiency with preserved noise level.
THE SOLUTION
For this object, the invention is characterized in that the end plate which is provided with the air inlet is shaped with a curve extending substantially arched from the inlet edge, in the direction toward the other end plate and further radially out toward the peripheral edge which is curved away from the other end plate, and that each blade is so designed in a peripheral segment, that the blade extends radially longer adjacent the end plate which is provided with the air inlet than at the other end plate. By this design of the fan wheel, a reduced level of noise is achieved, without any appreciable reduction of the working capacity of the fan.
DESCRIPTION OF THE DRAWINGS
The invention will be described hereinafter with reference to embodiments that are shown in the enclosed drawings, wherein
FIG. 1 in a partly broken plane view shows a fan wheel which is designed according to the invention,
FIG. 2 is a section along the line II--II in FIG. 1,
FIG. 3 shows in a larger scale in broken view a first embodiment of a fan wheel according to the invention, corresponding to FIG. 1 and 2, and
FIG. 4 shows in a corresponding way a second embodiment of a fan wheel according to the invention.
DESCRIPTION OF AN EMBODIMENT
The radial fan wheels shown in the figures comprise a number of fan blades 10 being symmetrically arranged with sub
REFERENCES:
patent: 3515498 (1970-06-01), Tomita
patent: 3584968 (1971-06-01), Keith
patent: 4647271 (1987-03-01), Nagai et al.
patent: 5328332 (1994-07-01), Chiang
patent: 5336050 (1994-08-01), Guida et al.
Look Edward K.
Nguyen Ninh
LandOfFree
Radial fan wheel does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Radial fan wheel, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radial fan wheel will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-725495