Sanyo Denki Co., Ltd.

Fujitsu Corporation

The University of Tokyo

Honami Oosawa

Katsumichi Ishihara

Yoshihiko Aizawa

Masahiro Suzuki

Akira Ueda

Tadashi Katsui

Atsushi Yamaguchi

Kazuhiro Nitta

Chisachi Kato

Akihiro Otsuka, Sr

Toshiyuki Nakamura

Atsushi Yanagisawa

Takashi Kaise

Jun Chieh Yen

Seiji Nishimura

There is disclosed an inline axial flow fan including at least first and second axial flow fans and arranged in an inline manner along an axial direction of a rotational shaft of a rotational driving apparatus. A first flow control grid is arranged in a gas discharge side of the first axial flow fan, and a second flow control grid is arranged in a gas discharge side of the second axial flow fan. The first flow control grid has a stator blade having a smooth circular arc leading edge shape matching a circular arc shape of the stator blade of the first axial flow fan and a trailing edge shape extending in parallel with a gas flow direction. The second flow control grid has a stator blade having a smooth circular arc shape matching a circular arc shape of the stator blade of the second axial flow fan.

Inline axial flow fan

Provided here is a counter-rotating axial flow fan with improved air flow-static pressure characteristics and reduced power consumption and noise compared to the related art. A plurality of struts are disposed to be stationary between a front impeller and a rear impeller in an air channel. A plurality of front blades are each formed of a swept-back blade, and a plurality of rear blades are each formed of a forward-swept blade.

Counter-rotating axial flow fan

A counter-rotating axial flow fan with reduced noise at the target operating point achieved without modifying a front impeller, a rear impeller, or a middle stationary portion is provided. An annular rib including a projecting surface for generating turbulent flow is formed on an inner wall portion of a casing at a position off from the middle stationary portion to a side of the rear impeller, the projecting surface extending radially inwardly of the inner wall portion and extending continuously in the circumferential direction of the inner wall portion. A fluid striking the projecting surface for generating turbulent flow is partially disturbed to form a turbulent flow before entering an area in which the rear impeller is provided. The turbulent flow suppresses flow separation of a fluid flowing along the surfaces of rear blades of the rear impeller from the surfaces of the rear blades.

A counter-rotating axial flow fan with improved characteristics and reduced noise compared to the related art can be provided. Defining the number of front blades as N, the number of stationary blades as M, and the number of rear blades as P, and defining the maximum axial chord length of the front blades as Lf, the maximum axial chord length of the rear blades as Lr, the outside diameter of the front blades as Rf, and the outside diameter of the rear blades as Rr, the counter-rotating axial flow fan satisfies the following two relationships: N&#x2267;P&#x3e;M; and Lf/(Rf&#xd7;&#x3c0;/N)&#x2267;1.25 and/or Lr/(Rr&#xd7;&#x3c0;/P)&#x2267;0.83.

A counter-rotating axial flow fan in which the shape of stationary blades of a middle stationary portion is optimized to reduce noise is provided. Defining the maximum axial chord length of front blades as Lf, the maximum axial chord length of rear blades as Lr, and the maximum axial chord length of stationary blades as Lm, a relationship of Lm/(Lf+Lr)&#x3c;0.14 is satisfied. Defining the maximum dimension between the blade chord for lower surfaces of the stationary blades and the lower surfaces as K, the maximum axial chord length Lm of the stationary blades satisfies a relationship of Lm/K&#x3e;5.8.

A first motor rotates, in one of two rotating directions, the first impeller including a plurality of front blades in a suction opening portion of a housing. The second motor rotates, in the other rotating direction opposite to the one rotating direction, the second impeller including a plurality of rear blades in a discharge opening portion of the housing. A plurality of stationary blades are arranged between the first impeller and the second impeller in the housing. When the number of the front blades is N, that of the stationary blades is M, and that of the rear blades is P, their relationship is defined as N&#x3e;P&#x3e;M. A length Lof the front blades measured in an axial direction is set longer than a length Lof the rear blades measured in the axial direction.

Counter-rotating axial-flow fan

The present invention provides an axial flow fan capable of increasing an air volume and static pressure more than conventional axial flow fans. A plurality of rotary bladesare disposed in a circumferential direction of a rotary shaftat equidistant intervals. A plurality of stationary bladesare disposed in the vicinity of a discharge openingof an air channel portionof a housing. The stationary blades are disposed in the circumferential direction of the rotary shaftat equidistant intervals. The number of the rotary blades is seven (7) and the number of the stationary bladesis eight (8).

Axial flow fan

The present invention provides an axial flow fan capable of increasing an air volume and a static pressure more than conventional axial flow fans, and also capable of reducing generation of noise. A guide wall portionis provided to form a guide groovebetween the guide wall portionand one stationary blade. The one stationary bladeis disposed in the vicinity of a lead wire engaging portionprovided at a housing. The guide groovereceives a plurality of lead wiresand guides the lead wiresto the lead wire engaging portion. When the guide wall portionis provided and the lead wiresare received in the guide groove, presence of the lead wiresmay have less adverse effect on the air volume and the static pressure, and may generate less noise.

A first motorrotates, in one of two rotating directions, the first impellerincluding a plurality of front bladesin a suction opening portionof a housing. The second motorrotates, in the other rotating direction opposite to the one rotating direction, the second impellerincluding a plurality of rear bladesin a discharge opening portionof the housing. A plurality of stationary bladesare arranged between the first impellerand the second impellerin the housing. When the number of the front bladesis N, that of the stationary bladesis M, and that of the rear bladesis P, their relationship is defined as N&#x3e;P&#x3e;M. A length Lof the front bladesmeasured in an axial direction is set longer than a length Lof the rear bladesmeasured in the axial direction.

An axial-flow fan with double impellers is provided that can produce a larger amount of air and a higher static pressure than can be achieved with conventional fans. The axial-flow fan with double impellers has a first axial-flow fan unit and a second axial-flow fan unit. The first axial-flow fan unit includes a first case, a first impeller and a plurality of webs that fix a first motor to the first case. The second axial-flow fan unit includes a second case, a second impeller and a plurality of webs that fix a second motor to the second case. The first case and the second case are coupled together to form a housing. The webs of the first axial-flow fan unit and the webs of the second axial-flow fan unit are combined together to form a plurality of stationary webs arranged in the housing. The number of front blades provided at the first impeller is set to five, the number of stationary blades is set to three, and the number of rear blades provided at the second impeller is set to four.

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Nagano, Japan

Honami Oosawa