DE2610273A1 - Centrifugal compressor impeller for pressure ratio over 1.79 - maximises flow by choosing relative blade thickness between specified limits - Google Patents

Abstract

The impeller (1) is intended for a centrifugal compressor whose ratio of maximum pressure at no flow (Pmax) to intake pressure (P1) equals or exceeds 1.79. The blade (2) thickness is selected such that the ratio (tan) of the volume between two adjacent blades (V2) to the total volume of Vz plus the volume of one blade (Vs) lies between a maximum value of 0.72 and a lower value defined according to a specified formula.

Description

SIEMENS AKTIENGESELLSCHAFT Our mark

Berlin and Munich VPA 74/3045 B

Impeller for side channel blowers

The invention relates to a side channel compressor. Will come with a Such a compressor achieves a compression of gases to high pressure ratios, then affects the compressibility of the Gases disadvantageously. The gas compressed into the vane cells is via the between the inlet and outlet opening of the Side channel located interrupter dragged. It then expands into the side channel on the suction side and thereby reduces the sucked in useful demand flow. This in turn becomes the achievable Efficiency severely limited.

The object of the invention is to reduce the aforementioned restrictions as far as possible and is based on the knowledge that the deterioration in efficiency is less, the smaller the gas volume dragged over the interrupter. This in turn means that the volume of the vane cells is kept as small as possible, which can be done by increasing the vane thickness. When calculating the impeller, the blade thickness goes into the formula = ^v z, ie in

V ₂₊ V _{3 is} the ratio of vane volume to vane cell plus vane volume. Since it was previously of the opinion that the thinnest possible blades result in a high pressure in side channel blowers, T 'values of 0.75 and above were provided. In contrast, the invention is chosen, the dimension of the blade thickness so as, ₂ c that the resulting from the ratio of vane cell volume to volume Schaufelzellen- plus blade pays between an upper Grenszwert of 0.72 and a lower limit

QjJ £ lies. Because of this smaller T-number,

( Pfflax ■ _ -j \ 2
P1
the pressure generation in the side channel slightly lower than for larger length values, but this can be compensated by the fact that the

"^ 37/0396

Volume flow loss dragged over the interrupter decreases more than the flow rate in the side channel. This in turn depends on the ratio of the pressure P _max », which is achieved at zero delivery - that is, complete throttling of the delivery flow - to the suction pressure P ₁ . This pressure ratio should be relatively large and thus the design of the invention the T number shall refer to side channel compressor, the pressure ratio ^{p max: P} 1 ^{'1' is 79} *

In Fig. 1 of the drawings, the associated f-values are plotted against the pressure ratios of a side channel compressor according to the invention. In addition to the two limit values for the number, there is an optimal value of 1 "= 0.85 -Vf _min ^v . The best efficiency of the side channel compressor is achieved with this T 'value.

2 of the drawings shows, in a purely schematic representation, an impeller 1 with the blades 2. V ₃ denotes the blade volume and V ₂ denotes the blade cell volume.

2 figures
1 claim

VPA 9/373/4008 709837/0396

e e r s e 11 e

Claims (1)

Claim Impeller for a rare channel compressor, the pressure ratio P _max at zero delivery to the suction pressure ρ ^ ü 1.79, characterized by such a dimension of the blade _{thickness that the ratio of the blade cell volume (V 2} ) to the blade cell (V_) plus the blade volume (V_) resulting number ^ lies between an upper limit value of 0.72 and a lower limit value X _m * _n m ° « ⁴ 5. ^ ² 709837/0396 VPA 9/373/4008