US2285976A - Centrifugal compressor - Google Patents

Description

June 9, 1942.

R. R. HUITSON CENTRIFUGAL COMPRESSOR ITWQe ntOT; .Fiobert R. Huibson,

Filed Jan. 27, 1941 His Attorn ey.

Patented June 9, 1942 Robert a. Huitson, Rugby, England, assignor to General Electric Company, a corporation of New York Application January 27, 1941, Serial No. 376,223

--- In Great Britain January 15, 1940 1 Claim. The present invention relates to centrifugal compressors which have a diffuser formed by two spaced rings or walls surrounding an impeller. More specifically, the invention relates to. the type of compressors in which one of the diffuser walls is movably arranged tovobtain the best efficiency at varying load output. Ordinarily the diffuser rings or plates are spaced so that the angle of the fluid flow at normal load is greater than 20, preferably about 35 throughout the major portion of its travel. The angle decreases as the, amount of fluid delivered decreases and vice versa. In order to maintain said angle at the desired value one of the rings or walls of the diffuser may be made adjustable.

l5, which latter has a flanged outlet portion 2|.

7 In order to convert some of the velocity energy of the medium discharged from the impeller a ring or vortex diffuser is provided for receiving the compressed medium from the impeller andconducting it to the scroll Hi. This diffuser has two side walls, one formed by the aforementioned wall l3 and another side wall or ring 22 forming a ring space together'with the wall i3.

In order to adjust the spacing of the rings I3 and 22, means are provided for moving the ring The object of the present invention is to provide an improved construction and arrangement of compressors in which one wall of the diffuser may be readily adjusted to obtain best efliciency at varying load output. This is accomplished in accordance with my invention by the provision of a plurality of adjusting screws engaging one of the diffuser walls or rings and being coupled with a rack and pinion or like means for actuating the screws to effect movement of one wall towards and away from the other wall of the diffuser.

For a better understanding of what I believe to be novel and my invention, attention is directed to the following description and the claim appended thereto in connection with the accompanying drawing.

In the drawing Fig. 1 illustrates a sectional view of a. compressor embodying my invention; Fig. 2 is a side view of Fig. 1; and Fig. 3 isga enlarged detail view of Fig. 1.

The compressor as shown in the drawing has a casing partly formed by two inner walls Ill.

modating an impeller l8 secured to a shaft I!- having a left hand portion supported on the wall I0. The impeller has a plurality of blades rigidly secured together. A right hand end portion of the shaft i9 located in the inlet i2 is supported on a bearing member secured to the inlet l2 by a plurality of fluid directing vanes.

During operation, medium is forced into the inlet l2 and upon compression by the impeller all of the screws, resulting in movement of the 221 towards and away from the ring l3. This means comprises a plurality of uniformly spaced screws 23 having threaded portions 24 engaging threaded portions 25 of, the wall 22. In the present example the right hand end of each screw 23 is supported on a journal bearing 26' on a reinforced, flanged portion 21 of the scroll IS. A left hand portion of each screw 22 is supported on a balibearing 28 held on the ring l3.

The screws are coupled by a rack and pinion arrangement. In the present instance the left hand portion of each screw 23 is provided with a pinion 29 engaging an annular rack 33. The rack 30 is rotatably supported by a plurality of circumferentially, uniformly spaced ballbearings 3 I, each of these bearings being held on a bracket 32 secured to an inner, flanged portion of the ring i3. One of the screws 23 is provided with an extension to which a handwheel 33 is secured by a bolt 34.

During operation, rotation of the handwheel 33 effects rotation of the screws 23 to which the wheel is fastened and simultaneously effects rotation of the rack 30 and the pinions 29 on, the other screws 23. This causes equal rotation of adjustable diffuser ring 22 towards or away from the ring l3, depending upon the direction of roing. In the present example the ring 22 is provided with an inner, cylindrical extension 35 having grooves 36 forming teeth 31 in close.

proximity to the flanged portion 21 of the scroll l5, thus constituting a labyrinth packing to reduceleakage of fluid along the outer surface of the ring 22 facing away from the ring I 3.

Having described the method of operation of my invention, together with the apparatus which I now consider to represent the best embodiment it is forced outward into the discharge scroll thereof, I desire to have it understood that the ing an impeller chamber and a scroll, an impeller located in the impeller chamber and having blades rigidly secured together, a ring diffuser for a conducting fluid from the impeller chamber to the scroll comprising a wall of the casing and a ring disposed within the casing and spaced from said wall, means forming a labyrinth packing.

1 between the ring and the casing, and means includinz a pluralityof circumterentially uniform- -15 v ly spaced screws engaging the ring and rotatably supported on the casing, a pinion secured to each v screw, a rack rctatably supported on the casing and engaging the pinions and a handwheel secured to one of the screws for adjusting the spacing between the wall and the ring said ring having an inner portion conically shaped and forming together with'a corresponding portion of the wall a space with an axial width decreasing in radial direction to assure a smooth flow of'fluid from the impeller into the difluserin the various positions of said rin ROBERT E. mn'rson.

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