Rotary kinetic fluid motors or pumps – With means for re-entry of working fluid to blade set – Cross flow runner
Reexamination Certificate
2000-01-26
2001-09-18
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
With means for re-entry of working fluid to blade set
Cross flow runner
C415S173300, C415S174200, C415S119000
Reexamination Certificate
active
06290456
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a ventilator or fan having a blocking device between its intake and pressure sides.
DE 30 48 571 A1 discloses a cross-flow fan having a nondeformable blocking device between its intake side and its pressure side. In the cross-flow fan the device may also serve as a turbulence former. A seal gap is formed between the rotor or the fan blades arranged on the rotor and the blocking device. With the known blocking device, this seal gap is necessary, since the rotor always has a residual imbalance, does not run one hundred percent true and/or is subject to dynamic deformation in operation, for example in the event of impact loads. However, the aerodynamic properties of the cross-flow fan are dependent, inter alia, on the size of the seal gap.
DE 195 27 605 A1 discloses, inter alia, a blocking device between a stator and a rotor of a turbo machine. The blocking device may be designed as a brush with bristle ends that keep the gap very small. However, this variant has a drawback in that a significantly audible rotational noise is generated when the rotor rotates. This noise may be perceived as a whistling or humming which may be disturbing to the user of the fans.
SUMMARY OF THE INVENTION
Therefore, the object of the invention is to provide a fan of this type, and either a cross-flow fan or an axial flow fan, which does not present this drawback.
A fan according to the invention has a rotor with a plurality of fan blades and a blocking device arranged between the intake side and the pressure side of the fan. The blocking device comprises a strip-like brush having a plurality of brush sections which are spaced apart from one another along the direction between the intake and pressure sides of the fan. Surprisingly, this blocking device significantly reduces the noise emissions from the fan, as compared with a known brush type blocking device, even though the ends of a plurality of brush sections are now arranged opposite the rotor. Moreover, because the blocking device comprises a brush, the seal gap can be made very small, which has a beneficial effect on the aerodynamic properties of the fan. Furthermore, the blocking device of the invention is not limited to use only for cross-flow fans of the type described above. Rather, the blocking device can also be used for radial fans and for so-called axial fans, which have a propeller, or the like, as the rotor. In all of these fans, the blocking device according to the invention is arranged between the intake side and the pressure side.
In one exemplary embodiment, the rotor comprises a cross-flow fan rotor, and the brush sections are spaced apart from one another along the running direction of the rotor. As the rotor rotates, each blade moves past two brush sections in succession.
If the rotor is designed as a cross-flow fan rotor, it is preferable for the blocking device to either be arranged on a turbulence former of the cross-flow fan or for the blocking device to form the turbulence former.
In another exemplary embodiment, the rotor comprises an axial-fan rotor, and the brush sections are this time spaced apart from one another transversely with respect to the running direction of the rotor.
In an axial fan, the blocking device, at least over certain areas, may surround a housing opening in which the axial-fan rotor is present or is mounted. In an axial fan, the blocking device according to the invention allows the pressure compensation between the pressure side and the intake side to be substantially reduced, since the brush-like configuration of the blocking element makes it possible to achieve an infinitesimally small seal gap, i.e. almost zero.
In a particularly preferred exemplary embodiment of a cross-flow fan the brush sections are also spaced apart from one another transversely with respect to the running direction of the rotor. Surprisingly, it has also been found that a blocking element of this nature can reduce noise emission still further.
In an exemplary embodiment of an axial fan, the brush sections are also spaced apart from one another in the running direction of the rotor. This makes it possible to further reduce the noise of an axial fan.
An exemplary embodiment of a fan in which the blocking device has precisely two brush sections is particularly preferred. This configuration is advantageous in that a noise reduction which is extremely good in relative terms is achieved with little outlay.
Furthermore, an embodiment is preferred in which the brush sections that extend radially inwardly toward the rotor extend parallel to one another. Alternatively, the distance between the brush sections may increase in the direction toward the rotor. For example, a V-shaped arrangement of the brush sections diverging toward the rotor is possible.
An embodiment of the blocking device having brush sections which form continuous strips is preferred. For the cross-flow fan, this means that the brush sections preferably extend over the entire axial length of the rotor. For the axial fan, the brush sections surround the rotor in the housing, so that a continuous strip is formed.
In another exemplary embodiment, the strip-like brush sections have bristle-free zones. These brush sections are therefore not of continuous design.
To form a bristle section, it is also possible to provide a plurality of individual bristle tufts which are arranged next to one another in a row. In bristle-free zones, there are no bristle tufts.
In another exemplary embodiment of a blocking device, the ends of the bristles of the brush sections which face toward the rotor are at different distances from the rotor. The advantages described above are achieved with a brush which has bristles of different lengths.
According to a refinement of the invention, the bristle-free zones of one brush section lie opposite zones of the other brush section which have bristles. In this way, the brush sections, which are not of continuous design, are arranged offset with respect to one another.
Preferably, polyamide is used as the bristle material. However, it is also possible for the bristles, particularly at their ends facing toward the rotor, to contain polyamide. Moreover, it is possible to use other suitable materials for the bristles, for example, metals, preferably steel, or metal alloys, thin metal strips or wires, or keratinous or composite materials, for example plastic-coated metal wires. An embodiment with a plastic film inserted between the bristles is also advantageous. Natural bristles may also be used as the bristle material.
A particularly preferred exemplary embodiment includes a blocking device in a single-row strip brush, as shown for example in DE 195 27 605 A1 mentioned above. But, this single-row strip brush has a brush-spreading element to form the brush sections. If appropriate, this spreader element may be retrofitted to a single-row strip brush. The bristle-spreading element is introduced between bristles, so that some of the bristles, as represented pictorially, are deflected to the left while the others are deflected to the right. Preferably, in this case, the bristle-spreading element is moved sufficiently deeply between the bristles for that element to virtually bear against the bristle carrier. The spreading element produces the v-shaped bristle configuration.
Other features and advantages of the present invention will become apparent from the following description of exemplary embodiments of the invention which refers to the accompanying drawings.
REFERENCES:
patent: 4398508 (1983-08-01), Moon et al.
patent: 4526509 (1985-07-01), Gay, Jr. et al.
patent: 5183382 (1993-02-01), Carroll
patent: 5297395 (1994-03-01), Ozu et al.
patent: 5518364 (1996-05-01), Neise et al.
patent: 5752802 (1998-05-01), Jones
patent: 5941685 (1999-08-01), Bagepalli et al.
patent: 3048571 (1982-07-01), None
patent: 8614073 (1988-04-01), None
patent: 19527605 (1997-02-01), None
Search Report dated Jan. 17, 2000.
Fichter Rolf
Widmann Ralf
Look Edward K.
LTG Aktiengesellschaft
Nguyen Ninh
Ostrolenk Faber Gerb & Soffen, LLP
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