SU1437582A1 - Centrifugal fan - Google Patents

Abstract

The invention makes it possible to increase the efficiency of the fan by reducing the eddy losses. An impeller having carrying and poking discs 2 and 3 with through holes 4 and regulating dampers crossing them is mounted in a spiral casing 1. Blades are placed between the disks, (l), each of which has a shaped part 6 and a hollow slat 7 forming a gap with it and a cavity communicated with the holes. Curvilinear L 10 are installed with a variable pitch along the circumference from the side of the discs and turned with a convex surface in the direction of opening the helix of the case. This arrangement allows creating a pulsating control flow with an increased amplitude of pressure pulsations in the hole area, since a pressure jump occurs due to a pressure difference on the concave surface L 10 and a pressure in the housing in the distribution area of the disks, 3 or 10 . (L

Description

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The invention of the OTFIOCHTCH for ventilation systems, in particular for centrifugal fans

The purpose of the invention is to increase efficiency by reducing the vortex loss.

FIG. 1 shows a centrifugal fan, a longitudinal section in FIG. 2 - the same, cross section; in FIG. 3, node I in FIG. 2 (on an enlarged scale), FIG. 4 is a view A of FIG. one; in fig. 5 is a view of B. n in FIG. one.

The centrifugal fan contains a spiral casing 1 and an impeller installed in it, having a carrier and sliding discs 2 and 3 with through holes 4 and regulating valves 5 that overlap them and located between the discs 2 and 3 of the blades each of which has a profile 6 and a hollow slat 7, forming with it a slit 8 and a cavity 9 communicated with the holes 4 of the disc 2 and 3

In this case, the casing is provided with curved blades 10, installed with a variable pitch t po of the circumference from the side of the disks 2 and 3 and facing a convex surface in the direction of opening the helix of the casing 1.

The fan operates as follows.

Under the action of the pressure difference, part of the working fluid flow (control flow) passing through the openings 4 in the disks 2 and 3, the cavity 9 and the slits 8, has a dynamic effect with a sufficiently large amplitude of pressure pulsation on the boundary layer that forms on the working or WELL (depending on the re

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pressure fan operation) blade surfaces.

: Equipping the body 1 with blades 10 allows a pulsating control flow to be created with an increased amplitude of pressure pulsations in the region of the holes 4 in the disks 2 and 3, since a pressure surge occurs with the curved blades 10 when pressure strikes the difference in the pressure of the concave surface of the blades 10 (zone of pressure) and pressure in the housing in the area of the disks 2 and 3 of the impeller. Thus, the proposed fan reduces the flow rate of the control flow to eliminate stagnant and vortex zones and, as a result, increases the efficiency.

Claims (1)

Invention Formula A centrifugal fan containing a spiral casing and an impeller mounted therein has a carrying and covering discs with through holes and control valves that intersect them and placed between the blades discs, each of which has a core part and a hollow slat, forming with it slots and the cavity communicated with the holes of the disks, characterized in that, in order to increase the efficiency by reducing the eddy losses, the housing is equipped with curvilinear blades installed with a variable pitch around the circumference the rions of the discs and the convex surface facing the open spiral of the case. I Editor I. Casard Compiled by E. Zhmulin Tehred L. Serdyukova Proofreader E. Lonchakova Order 5873/35 Circulation 574 VPIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 I cszs Subscription