Fluid reaction surfaces (i.e. – impellers) – Rotor having flow confining or deflecting web – shroud or... – Radially extending web or end plate
Patent
1995-12-27
1998-04-21
Denion, Thomas E.
Fluid reaction surfaces (i.e., impellers)
Rotor having flow confining or deflecting web, shroud or...
Radially extending web or end plate
416185, 416223B, B63H 116
Patent
active
057411182
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a multiblade radial fan and a method for designing and making the same.
BACKGROUND ART
The radial fan, one type of centrifugal fan, has both its blades and interblade channels directed radially and is thus simpler than other types of centrifugal fans such as the sirocco fan, which has forwardly-curved blades, and the turbo fan, which has backwardly-curved blades. The radial fan is expected to come into wide use as a component of various kinds of household appliances.
However, design criteria for enhancing the quietness of the radial fan have not yet been established. This is because the radial fan has been applied mainly for handling corrosive gases, gases including fine particles and the like, taking advantage of the fact that radial fans having only a few blades enable easy repair and cleaning of the interblade channels. Fans used for this purpose do not have to be especially quiet.
A number of design criteria have been proposed for enhancing the quietness of centrifugal fans. For example, Japanese Patent Laid-Open Publication Sho 56-6097, Japanese Patent Laid-Open Publication Sho 56-92397, etc., propose elongating the interblade channels to prevent the air flow in the interblade channels from separating, flowing backward, etc. Japanese Patent Laid-Open Publication Sho 63-285295, Japanese Patent Laid-Open Publication Hei 2-33494, Japanese Patent Laid-Open Publication Hei 4-164196, etc., propose optimizing the number of blades of a sirocco fan with a large diameter ratio.
Japanese Patent Laid-Open Publication Sho 56-6097, Japanese Patent Laid-Open Publication Sho 56-92397, etc., disclose only the concept that the interblade channels should be elongated. They do not disclose any correlation which should be established among various fan specifications for optimizing the quietness of the fan. Thus, the proposals set out in Japanese Patent Laid-Open Publication Sho 56-6097, Japanese Patent Laid-Open Publication Sho 56-92397, etc., are not practical design criteria for obtaining a quiet fan.
The proposals of Japanese Patent Laid-Open Publication Sho 63-285295, Japanese Patent Laid-Open Publication Hei 2-33494, Japanese Patent Laid-Open Publication Hei 4-164196, etc., can be applied only to sirocco fans with large diameter ratios. Thus, these proposals are not general purpose design criteria for obtaining a quiet fan.
SUMMARY OF THE INVENTION
The inventors of the present invention have conducted an extensive study and found that there is a definite correlation between the quietness of a multiblade radial fan and the specifications of the impeller of the multiblade radial fan. The present invention was accomplished based on this finding.
The object of the present invention is therefore to provide methods for systematically determining the specifications of the impeller of a multiblade radial fan under a given condition, based on the above-mentioned definite correlation, and optimizing the quietness of the multiblade radial fan. Another object of the present invention is to provide a multiblade radial fan designed based on the method of the present invention.
According to a first aspect of the present invention, there is provided a method for designing a multiblade radial fan, wherein specifications of the impeller of the multiblade radial fan are determined so as to satisfy the correlation expressed by the formula .nu..gtoreq.-0.857Z.sub.1 +1.009 (in the preceding formula, .nu.=r.sub.0 /r.sub.1, and Z.sub.1 =(r.sub.1 impeller, r.sub.1 is the outside radius of the impeller, n is the number of radially-directed blades, and t is the thickness of the radially-directed blades).
According to the first aspect of the present invention, there is also provided a method for designing a multiblade radial fan, wherein specifications of the impeller of the multiblade radial fan are determined so as to satisfy the correlation expressed by the formulas .nu..gtoreq.-0.857Z.sub.1 +1.009 and 0.8.gtoreq..nu..gtoreq.0.4 (in the preceding formulas, .nu.=r.sub.0 /r.sub.1, Z.sub.1
REFERENCES:
patent: 3734640 (1973-05-01), Daniel
patent: 3864055 (1975-02-01), Kletschka et al.
patent: 4022423 (1977-05-01), O'Connor et al.
Hatakeyama Makoto
Shinbara Noboru
Denion Thomas E.
Toto Ltd.
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