DE2416165A1 - Adjustable stator blade diffuser for centrifugal compressor - has hollow blades with one resilient wall and pressurising means - Google Patents

Abstract

The diffusor has an adjustable cross-sectional flow area. Each hollow stator blade is provided with a resilient wall on the side which is at the shortest distance from the entry side of the adjacent blade and with an inlet orifice for a pressurised fluid. The resilient wall may be spring-loaded to return to its un-deformed condition. The internal pressure in the hollow blade may be controlled as a function of the position of the pre-swirl blades. An advantage, is the fact that separate sealing elements are not essential, since the common control of the diffusor cross-sectional area provides static sealing against the pressure medium.

Description

Vane diffuser.

The invention relates to a guide vane diffuser with adjustable Flow cross-section for centrifugal compressors.

Let off radial turbo compressors with bladed diffusers good efficiencies can be achieved in the design point. With smaller suction volume flows however, there is a strong decrease in the degree of efficiency because the diffuser cross-section is then is too large and the flow to the diffuser vanes is below another Angle than the blade angle takes place.

It is known to remedy this by pivoting diffuser guide vanes to change the narrowest cross-section and the angle of attack, which changes the characteristic curve can be influenced significantly.

However, this method has the disadvantage that a special adjustment mechanism must be present and that relatively large torques when pivoting the blades can occur, especially if the diffuser side walls are dirty during operation are. This measure is also limited to diffusers with parallel side walls, It is also known for fixed diffusers by moving the side walls to reduce the diffuser cross-section. Again, it is disadvantageous that although the area is reduced, but the blade intrittangle i the flow angle is not adjusted.

It was therefore the task to create a bladed diffuser, in which both flow cross-section and flow angle in a simple manner can be adapted to the respective operating requirements.

It has now been found that a corresponding JJjeitschaufeldiffusor can create if the guide vanes to adjust the flow cross-section hollow and on the side which is the smallest with the tongue of the neighboring shovel Distance f forms, with an elastic wall and with a feed for a fluidic or gaseous pressure medium are formed, the elastic Walls of the guide vanes with return elements.

and the internal pressure of the guide vane, if applicable is coupled with the swirl vane setting.

FIG. 1 shows a guide vane ring according to the invention in cross section.

1 denotes the fixed part of a guide vane, 2 the elastic part Trend of this guide vane, namely in the normal position and in the protruding position 2 ', 3 the interior of a guide vane, 4 the feed for the pressure to the support vane, 5 the hollow side wall, 6 the feed for the pressure to the side wall, 7 the return elements for the elastic wall 2, f the narrowest guide vane distance at the diffuser inlet, i the angle between the guide vane and the circumferential direction.

From the drawing it can be seen how the elastic wall 2 of the hollow Beitschaufel 1 bulges under the action of pressure to position 2 'and thus makes both the flow cross section and the angle of attack adjustable, because by supplying pressurized gases or fluids via the Feed 6 to the side wall 5 and from there via feed bores 4 to the individual Guide vanes can be a more or less with volume-dependent control of the overpressure strong deformation of the elastic wall 2 can be achieved, which is a 'change in the middle Beitschaufellerinkels α to the flatter at partial load Direction of flow causes.

A major advantage of the invention is that a seal of rotating adjustment elements is required. All for change The components required for the diffuser cross-section are through static seals opposite de; Pumped medium sealed.

Claims (1)

Claim: Guide vane iffusor with adjustable flow cross-section for centrifugal compressors, d a d u r c h e k e n-n z e i c h n e t that for setting the flow cross-section the guide vanes (1) hollow and on the side which is connected to the tongue of the neighboring one Shovel forms the smallest distance, with an elastic wall (2) and it one Feed (4) are designed for a fluidic or gaseous pressure medium, where appropriate, the elastic walls (2) of the guide vanes (1) with return elements (7) and the internal pressure of the guide vane, if necessary with the swirl vane setting is coupled.