DE2524555A1 - Axial flow blower of high energy transfer - has rotating blades of various angular distribution and separation - Google Patents

Abstract

An axial flow blower has several blades (3, 4) which are separated from each other to varying degrees, and which have profiles of unequal sequence to produce higher energy in the flow which passes the blades in a narrow blade channel, so that an almost equivalent energy output into the blast flow is generated to the energy input to rotate the blades. The blades may be plates of similar shape but with different angles of inclination to each other. This arrangement avoids hydraulic loss and thereby improves the efficiency of the blower. The total noise level can be reduced by matching the number of blades with the revolutions.

Description

5-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo, Japan

Axial flow fan

The invention relates to an axial flow fan and in particular to an axial flow fan with a so-called irregular pitch, in which the blades of are unevenly spaced from one another.

In an ordinary axial flow fan, the blades are generally equidistant from one another as Figure 1 shows. A housing with a so-called irregular pitch is also used, in which the blades for supply a frequency or a product obtained by multiplying the number of sheets with the speed, in which the Noise caused in the axial fan and its higher harmonics are significant, at any unequal distance from one another are to reduce the noise level as a whole, (Figure 2). Occur in the fan with an irregular slope a flow a that passes through a wide leaf

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509849/0803

BORO MONKS: TELEX: TELEGRAM: PHONE: BANK ACCOUNT: CHECK ACCOUNT: 8 MONKS 22 1-886 44 INVENTION BERLIN BERLINER BANK AQ. W. MEISSNER, BLN-W ST. ANNASTR. 11 INVEN d BERLIN 030/888 6037 BERLIN ti 122 82-108 TEL: 068/32 36 44 030/886 33 82 368671800

passage, and a flow b passing through a narrow blade passage, as shown in Figure 2b, so that the energies given to the unit volume of a liquid are not equivalent. Since the pressure increase and the flow angle one through the wide blade passage passing flow a is different from those of a flow b passing through a narrow blade passage hydraulic loss is caused until the flows through the fan are equal will. Furthermore, because of the low efficiency of the blade assembly, the efficiency of this fan makes the With these currents, a turn for the worse works more than a fan with a regular gradient. It follows that the invention has the task of eliminating the errors of fans with an irregular pitch eliminate without giving up its benefits.

The invention is described using an exemplary embodiment with the aid of the drawings. In these show:

Figure 1 shows an ordinary axial flow blower with the Front in

Figure 1a and an embodiment of its blade arrangement in Figure 16;

Figure 2 shows an ordinary fan with an irregular pitch with the front on Figure 2a and the Blade arrangement in Figure 2b; the

3 to 6 show exemplary embodiments of an axial flow blower s according to the invention, thereof shows

Figure 3 is a front view;
Figure 4 is a side view;

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Figure 5 shows the blade arrangement; and

Figure 6 shows a blade arrangement with staggered angles.

In Figures 3 to 5, 1 is the outer housing, 2 is the drive hub, 3 and 4 are the movable sheets, the spaces (pitch) of which are unequal and wide Leaf passage a and a narrow leaf passage b result. When the blade arrangement of this fan is in sight of the bright arrow moves, the currents run in the direction of the black arrow.

On the side of the sheet 4 facing the wide sheet passage a, there is a chamber that is larger than the of the sheet 3, and on the side of the sheet 4, which faces the narrow sheet passage b, there is a chamber, which is smaller than that of sheet 3. The sheet 4 is thus thicker than the sheet 3 and both sheets are different Profiles.

Since the wide passage a from the black side of the sheet 4 with a large chamber and the opposite side of sheet 3 with a small chamber and the narrow passage b from the black side of sheet 4 with a large chamber is formed, accordingly, the flow passing through the wide passage a can be larger Absorb energy as the flow passing through the narrow passage b. Therefore, the same energy can increase per unit volume flows through a leaf passage go through, are allocated by properly chosen leaf profiles of leaves 3 and 4.

It is thus possible to eliminate the hydraulic loss that results from the unification of the unequal energies after the currents have passed through the fan, similar to a conventional fan with irregular steepness

509849/0803

252A555

production results, and thereby the efficiency of the fan to improve. Furthermore, the noise level as a whole can be reduced because of the dispersion of the noise at one frequency by multiplying the number of blades by the speed of the fan with a regular pitch is obtained.

In addition, when the movable blades are plates, the chamber of the blade 4 may preferably be larger than that of the Sheet 3. The leaf passages can each have two or have three different slopes or all can be mutually different and the length of the chord of the leaf the sheet with the wide passage may be larger than that of a sheet with a narrow passage so that it is uniform Energies per unit volume of fluid can be obtained. In a different way can have the same effects by changing the stagger angles of the blades without inducing the blade profiles. As Figure 6 shows, can a sheet 4, which is with its black side on the side of the wide gap, standing and a Sheet 3 »that with its black side a narrow space has to be lying down.

In the drawing, θ denotes a staggered angle, where preferably G _x . <Op is.

The invention has been described on the basis of the exemplary embodiment. According to the invention are with a fan so-called irregular slope, in which the leaves are unevenly spaced from each other, the leaf profiles accordingly the inequality of their slope unequal, so that almost the same energy per unit volume is transferred to the fluid, which passes through the wide sheet passage, and is supplied to a fluid flowing through the narrow Passage through

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Therefore, errors such as an increase in hydraulic losses and an increase in fan efficiency can occur conventional fan with an irregular pitch while maintaining the characteristics of the fan (lowering the noise level) can be prevented.

- patent claims -

509849/0803

Claims (1)

Patent claims: -Axialetrömungsgebläse, characterized in that several leaves (3 »4 ·) different from each other are removed and have profiles which are unequal to one another in order to transfer a greater amount of energy to a flow that goes through a narrow leaf passage, so that almost the same energy per unit volume of the fluid used for the blades. 2. Axial flow fan according to claim 1, characterized in that that on the side of a sheet (4-), which points to the wide passage (a), or on his black side there is a chamber that is larger than that of the adjacent other sheet (3), and the one on the side of the sheet that points to the narrow passage (b) or the side facing away from it Chamber is located, which is smaller than that of the adjacent other sheet. 509849/0803 BORO MONKS: TELEX: TELEGRAM: PHONE: BANK ACCOUNT: CHECK ACCOUNT: 8 MONKS 22 1-8H44 INVENTION BERLIN BERLINER BANK AQ. W. MEISSNER, BLN-W ST. ANNASTR. 11 WVENd BERLIN 030/888 80 87 BERLIN SI 122 82 -109 TEL: 019/23 88 44 030/18 «23» 2 3096716000 J. Axial flow fan according to claim. 1, characterized in that that the leaves consist of plates, and that the chamber of one leaf is larger than that of the another leaf that is adjacent to the first leaf. 4. Axial flow fan according to claim 1, characterized in that that the blades have the same profile and different stagger angles. 503849/0803