US3790300A

US3790300A - Multi-function centrifugal blower unit

Info

Publication number: US3790300A
Application number: US00254760A
Authority: US
Inventors: M Gilliland
Original assignee: Ametek Inc
Current assignee: Ametek Inc
Priority date: 1972-05-18
Filing date: 1972-05-18
Publication date: 1974-02-05
Anticipated expiration: 1991-02-05

Abstract

A two-stage centrifugal fan section with a first suction inlet, a central diffuser chamber section accepting the first section discharge and having circumferentially spaced second and third suction inlets, and a final generally tangentially discharging centrifugal fan section receiving diffuser section discharge, all incorporated in a composite housing to form a motor-blower unit with an induction motor section of which the fan mounting rotor shaft is supported in a housing end wall offset from the housing axis to provide with a local pinch formation in the final section interior, a scroll or snail shell type discharge. The diffuser section is vaned to isolate and allocate certain flows to respective regions of the final fan inlet and thereby promote stable pumping operation at the three inlets independently at distinct flow and/or pressure differential conditions.

Description

United States Patent Gilliland MULTI-FUNCTION CENTRIFUGAL BLOWER UNIT [75] Inventor: Michael L. Gilliland, Kent, Ohio [73] Assignee: Ametek, Inc., New York, NY.

[22] Filed: May 18, 1972 [21] Appl. No.: 254,760

[52] US. Cl. 415/219 C, 415/198 [51] Int. Cl. F0ld 1/02, FOld 25/24, Fold 9/00 [58] Field ofSearch 415/198, 199 A,2l9 R,2l9 C,

[111 3,790,300 [451 Feb. 5, 1974 Primary Examiner- -Carlton R. Croyle Assistant Examiner-Louis J. Casaregola Attorney, Agent, or Firr n-Philip D. Golrick ABSTRACT A two-stage centrifugal fan section with a first Suction inlet, a central diffuser chamber Section accepting the first section discharge and having circumferentially spaced Second and third suction inlets, and a final generally tangentially discharging centrifugal fan Section receiving diffuser Section discharge, all incorporated in a composite housing to form a motor-blower unit with an induction motor section of which the fan mounting rotor Shaft is supported in a housing end wall offset from the housing axis to provide with a local pinch formation in the final section interior, a scrollor snail shell type discharge. The diffuser Section is vaned to isolate and allocate certain flows to respective regions of the final fan inlet and thereby promote stable pumping operation at the three inlets independently at distinct flow and/or pressure differential conditions.

10 Claims, 7 Drawing Figures PAIENTED 51974 33790300

sum

2 or 5 FIGZ ' PATENTEBFEB 51974 FiGB SHEU 3 BF 5 PATENTEU 51974 3 790 300 SHEET 6 BF 5 PAIENTEDFEB 1 14 3.700.300

sum 5 0r 5 FIG? MULTI-FUNCTION CENTRIFUGAL BLOWER UNIT Though in its broader aspect the present invention has application to other fluids and to handling simultaneously of distinct fluids, especially in the same state, it will be hereinafter discussed and a particular embodiment described in terms of the pumping of air, as a fluid handled in three streams for different services and performances.

Where it is required to pump or move simultaneously two or more distinct streams of air at different rates and/or distinct pressure conditions, especially where stable operations are required for each stream, hitherto there have been used either a single pump and motor of adequate capacity and a system of pressure and flow controls, or separate respective pumps or blowers powered by respective motors, though at times with the pumps driven from a common motor shaft. This multiplication of components has been necessary in prior practice to isolate the air streams or flows from each other in order to provide stable operations at the desired conditions for each service in question generally as an alternative to using comparatively expensive pressure and flow controlling devices to the same end.

Such multiplicity of components often entails decided disadvantages in installations where space is at a premimum, or mounting areas limited, or weight is desirably to be kept low; and obviously entails further expense both for material and other manufacturing costs in the several components, as well as for their mounting in the environment of use.

The present invention enables the pumping or two or more air streams at different air flow rates and/or pressure differentials by a single electric motor powered suction or blower unit having a respective inlet for each stream and discharging to atmosphere through a common outlet, and obtaining stable respective performance for the air moving funtion corresponding to each inlet. Further a particular embodiment is disclosed representing compact and economic blower unit structure which is obtainable by application of the broader aspects of the invention.

In the particular embodiment of the invention hereinafter described, air is centrifugally pumped for three different services connected to the respective housing inlets, at respectively different flow rates and two different pressure differentials, by a first fan section providing the performance required for two services and by a second fan section discharging ultimately to the first providing the performance required for a third service; for all of which the fans are driven commonly on one motor shaft; the total air of all three services discharged through a common outlet to atmosphere. Between the fan sections, there is provided a diffusing chamber section guiding and delivering air from the discharge of the second mentioned fan section and from the first and second named inlets, to the eye or intake of the first named centrifugal fan section in a manner which attains the stable operation and pumping under the desired conditions for the three services.

In the so-called diffuser section, the three air streams enter near the periphery, the discharged air of the second-mentioned fan section mixing with the air of one of the diffuser section direct inlets, and the mixed air stream and the stream from the other direct inlet are separately directed to a central inlet or eye, for the final fan section discharging to atmosphere by respective series of inward fixed diffuser vanes. Two of the vanes, as divider vanes, begin at the diffuser circumferential wall and run inward to the eye to divide the chamber into two flow spaces, respectively corresponding to the service inlets opening to the chamber, the remaining intervening blades or vanes in each series terminating short of the circumferential wall to permit flow from the circumferential wall inwardly.

By the location of the inner ends of the divider vanes on the circumference of the eye to the final impeller chamber, flow space at the eye is allocated percentagewise corresponding to the percentage of the total mass flow in the blower represented by the air intended to enter the corresponding division of the diffuser section chamber.

In the particular circumstances, as in an embodiment here disclosed, where the pressure differentials under which the air streams move are not greatly different from each other, and the air is subjected to actual pressure not much different from the atmospheric, such proportioning of the flow may be based upon the volume flow rates.

The combination with the diffuser enables the two fan sections to handle the three air streams with distinct stable performances, though transiting a common fan, so that practically the plurality of services may be handled in one compact unit.

The immediate consequent advantages in savings of component costs, in simplified and space-saving installation, and opportunity for overall system weight reduction, for example, while attaining desired performances, are obvious. Further in the disclosed embodiment of the invention, particular impeller disposition and impeller housing form and structure is disclosed based on a generally cylindrical form, yet providing a good approximation to a scroll housing and discharge, which simplifies fabrication and tooling design with attendant cost savings for-the type of structure and function achieved It is the general object of the present invention to provide a fluid pump unit with centrifugal impellers on a common driven shaft capable of moving a plurality of fluid streams with stable performance.

A further object of the invention is to provide a centrifugal air blower or suction unit with impeller driven by a common motor shaft capable of moving air for a plurality of services drawn in at respective housing inlets and discharged from a common outlet of a final impeller section handling the total air flow.

A further and more specific object in the particular disclosed embodiment is to provide a scroll type discharge impeller housing section in a relatively simple and low cost manner.

Other objects and advantages will appear from the following description and drawings wherein:

FIG. 1 is an elevational view, for convenience of reference denominated a front end elevation, of an electric motor-blower unit embodying the invention;

FIG. 2 is a side view, partly in elevation and partly in irregular section taken generally as indicated by 22 in FIG. 1;

FIG. 3 is primarily a front elevational view of a blower housing member showing certain details of an intermediate or diffuser chamber structure in the unit;

FIG. 4 is a rear view of the housing component constituting the principal part of FIG. 3;

FIGS. 5 and 6 are fragmentary detail elevations of FIG. 3 viewed as indicated at 55 and 6-6; and

FIG. 7 is a front view of a second housing member.

GENERAL ARRANGEMENT The drawings show an electric motor driven blower or suction unit embodying the invention comprising (see FIGS. 1 and 2) a motor M united with blower B, which pumps air for three different service requirements, therefore handles three different air streams, drawn into the respective inlets, P,Q,R, and discharges the total of the air through one unit outlet D. Merely to establish a convenient basis for description, the orientation of FIG. 2 is used for top, bottom, front and back relations, the left end being considered the front of the unit.

In a composite blower housing later described, centrifugal impeller F-l on the motor shaft S in a chamber adjacent motor M peripherally discharges to outlet D; at the opposite end of the housing, the shaft carries two like centrifugal impellers F2 and F-3 housed in a twostage arrangement drawing in air at inlet R; and in what, relative to the final fan F-l and its chamber, may be termed an antechamber receiving directly the air streams entering inlets P, Q, and also the air stream entering R and discharged from the two-stage impellers, a diffuser-like structure Z controls air flow to F-l.

The important diffuser structure Z, efficiently directs, as to two streams mixes, and introduces the air streams through a common inner wall eye aperture I providing an inelt to and aligned with adjacent central intake or eye of impeller F-l, so that the total air handled moves without any appreciable interaction upon the air moving performance the blower for the three air streams which it brings into the respective inlets.

HOUSING AND IMPELLERS Circumferentialy surrounding shell portions and certain transverse walls for the above described structures are provided by

members

11, 12, l3, 14 in a composite housing basically cylindrical in design shape apart from certain divergencies for the outlet D and inlet P, wherein the axis X-s of the motor shaft S is paralleloffset upwardly and to the right from the cylinder axis X-c, as viewed from the front end and designated in a FIG. 3 for example.

The right side of cylindrical portion 12a is fitted endwise onto an interrupted circular flange llr on the left face of wall 11b in a rabbet-type joint; a shallowly cupped front end cap member 13 has its internally rabbetted shallow cylindrical rim 13a fitted onto the external rabbet left end of the cylindrical rim wall or shell portion 12a; and the open right rim or shell end 11a is fitted on a generally rounded disk-like end member 14, at an inward flange 14a spaced from the margin forming in effect a rabbet. These

blower housing elements

11, 12, 13, 14 are primarily secured by external longitudinal bolts 15 through projecting apertured lugs 13b and 14b of the end members; but screws 16 locally hold respective upwardly projecting parts of

members

11, 12 forming the inlet P.

Member 14 in elevational outline diverges from circular in matching member 1] to form the outlet D and discharge structure for the chamber of impeller F-l, Coaxially about an integral bearing socket formation Me with axis offset from the circular center as required for the shaft, a short rabbeted cylindrical flange 14f accepts motor field cylindrical housing 17 fitted thereon and in turn having a rabbeted motor end bracket member 19 similarly fitted on its opposite end. With external bolts 18 through radially projecting lugs 19a and threaded into bosses 14g on member 14, the latter serves both as an outer end wall for the chamber of impeller F-l, hence of the blower housing, and also as a shaft bearing supporting motor end bracket. It may be noted here that motor M is appropriately an induction motor.

The support is generally conventional for the impellers, with the respective end disks centrally clamped by spacer washers and

sleeves

21, 22, 23, 24 between the inner race of bearing 25 and clamping nut 26 threaded on the shaft S; and so also sheet metal structure of each impellerinsofar as comprising an end disk centrally apertured for the shaft S, an annular disk having a large central opening as the impeller eye or intake, and a series of appropriately formed vanes or blades with edge nibs or lugs projecting through corresponding apertures of and headed down against the disks in rivet like fashion to secure the impeller components into a rigid assembly. Stationary sheet metal disk or

wall elements

28 and 31 are similarly secured on stationary vanes later described.

As integral parts of housing member 12, a transverse round partition or wall 12b, on its left side as seen in FIG. 2, has a series of integral vanes 12v angularly spaced about a large central circular opening l2d offset from the cylindrical axis corresponding to the shaft offset; the vane free edges mounting a sheet metal end disk 28, parallel to 121; and centrally apertured for a running clearance with spacer 23, thus defining a first stage impeller chamber and forming a so-called stationary fan, conducting air discharged peripherally from the first stage impeller F-3, around the edge of 28 equally peripherally spaced from 12a, back inwardly toward the shaft to discharge through 12d into the aligned intake eye of second stage impeller F-2. These structures are conventional except for a certain asymmetry imposed by the axis offset, the vanes 12v originating in wall 12a and running with like inclinations to and equally angularly spaced about 12d. (See FIG. 7).

The oblique tubular inlet formation 13c for the inlet R opens through the end wall 13d of member 13 over an area spanning and generally symmetrically disposed relative to the eye of the first stage impeller.

The peripheral wall portion continues to the rear (right in FIG. 2) of wall 12b in cylindrical form to closely fit a circular disk 31, carried on the edges of the internal vanes of member 1 1, defining the chamber for the second stage impeller F-2.

Integral external mounting pad formations 12f align with like shorter pad formations 11f to form unit mounting feet. Otherwise the exterior of the member 12 is cylindrical, except for the forwardly oblique hollow upward projection 12p, the open back (right in FIG. 2) side of which is closed by a matching flat projection 11p of member 11, secured locally by screws 16 to form inlet P. The shape of the inlet structure P is gathered from FIGS. 1, 2, 3 and 4.

For the inlet O, an opening in the cylindrical wall portion 12a at the location shown (at left in FIG. 1) is provided with an inserted sleeve for attachment of an air conduit, as also may be done at P and R to simplify fabrication ofmembers l1, 12, 13 as say die castings.

The represented directions of the centerline of the inlets-P, Q, R, and the outlet D are dictated by the particular intended environment of use for the specific motor blower unit here shown, except as may be otherwise here specified.

The lower margin of member 12 at the lower region as cast is recessed or relieved to accommodate a projecting part (dotted at US in FIG. 2) of outlet structure provided on member 11. Particulars of the chamber and outlet structure for the final impeller F-3 are described below.

In the housing component ll, at the left end of the circumferential shell portion 11a, the integral partition 11b having the previously mentioned circular opening or eye I offset from the cylindrical axis to be concentric with the shaft, thus provides the inner or left end wall of the chamber defined with 11a and 14 for impeller F-l, having an inlet aligned with the impeller intake eye. In the bottom part of the housing (see FIGS. 1, 2, 3, 4,) the peripheral wall 1 1a diverges tangentially from cylindrical, widening out in radial sense into the more or lesstangential-shell wall portion l lt running into the outlet structure D, while above the latter, an integral formation 11h (see FIG. 4) curves inward away from the cylindrical portion of rim 11a forming a pinch region approaching theedge of the impeller F-3 and then rounding into a straight portion 11k continued out into a top wall of outlet D; 11h and 11k being notched adjacent 11a to accommodate the flange 140.

As well in the lower region beginning well before 1 It, the wall 11b has an arcuately extending or annular sectorially shaped forward offset 11s, as seen in FIG. 2 offset to the left in the right end region of member 11, which also gives a larger flow area leading toward the outlet D (see FIG. 3).

As previously mentioned, the lower region of member 14 diverges from a round or disk shaped to a matching form to close the back of member 11 including the right side (as viewed in FIG. 2) of outlet D.

The above described shell peripheral formations conjoined with the aforementioned offset of the rotor shaft axis (upward and to the right as viewed in FIG. 1) gives a good approximation by simple structure to a snail shell peripheral casing shape in which the flow space for the peripheral discharge of impeller F-l is radially expanding, in a circumferential direction, (counterclockwise, the direction of impeller rotation as viewed in FIG. I) from the pinch 11h around to the outlet D, with, moreover, an axial enlargement of the flow space near the outlet D, as provided by the offset 11s.

DIFFUSER STRUCTURE-ANTECIIAMBER The structure of the antechamber and diffuser section is best seen and discussed relative to FIG. 3 in conjunction with FIG. 2.

- On the generally flat front or left face of the common inner wall llb, as well as flange llr, there is a series of projecting integral fixed blades or vanes with inner ends terminating at the opening I, the coplanar left edges of which support the sheet metal disk 31 forming also the front wall of the diffuser or antechamber. The shape and disposition of the vanes or blades relative to the eye opening I into the last impeller chamber and relative to the inlets P and Q, and also relative to the dividing the annular flow space to and about the eye I into respective sectors corresponding to inlets P and O; that is, counter clockwise between 11x to 11y, providing flow space from inlet Q to the eye I, and from 11y to 1 1x flow space from inlet P to the eye I. The further diffuser vanes or blades llz, have outer ends spaced from the housing shell portion 12a, for distribution of each of the air flows; all of these vanes, excepting 11x, and of this the inner end, running radially to the edge of the eye or discharge aperture I. Outwardly beyond a portion running radially from the edge of the wall eye aperture which is the vane portion effectively dividing the arcuate extent of the aperture for flow purposes, the vane llx is angled back clockwise (as viewed from the front, see FIG. 3) to accommodate a desired location of inlet O, which in the fitted shell portion 12a is located just counter clockwise of the outer end of 11x.

Further, over the lower sector handling air from Q, running counter clockwise from a radius just below the location of the inlet Q toward 11y, the margin of wall disk 31 is incised with spaced notches, between which the residual edge tabs (here thirteen) are twisted about 45 to slope inwards in the counterclockwise direction, thereby forming a series of louvers or peripherally located diffuser blades 31b in what represents the discharge from the second stage impeller chamber and the inlet to the antechamber for the air stream ultimately entering the casing at R.

The annular sectorial offset 11s of the wall 11b into the antechamber space, which happens to fall under the series of blades or vanes 31b, does not impair the efficient entry of the air from Q and the twostage impeller, and as may be noted in FIGS. 3 and 5, the left or clockwise end of the offset sector 11s curves or blends upwardly from the main plane face of 11b to the maximum offset which yet is well spaced from wall 31, and at the right end (see FIG. 6) tapers or slopes somewhat into the outlet D. The flange formation llr, though interrupted for the region of inlet P, is carried up with the offset 11s to provide the rabbeted type joint even in the recessed region of 11a accommodates the offset.

The inner ends of the dividing blades or vanes llx and 11y are so located that the peripheral space about, and for flow to, theeyel into the final impeller section is allocated according to the mass flow which is intended to be handled in each sector of the chamber. In other words, the arcuate extent of the eye to which each sector feeds is directly proportional to that fraction or percentage of the total mass flow into the eye which is represented by the mass flow in the sector.

Thus the arcuate extent of the eye to which P feeds, the counterclockwise arc from llx to lly at the eye, is proportional to the ratio of the flow into inlet P to the total flow; the balance of the eye periphery, to ratio of the sum of the mass flows into Q and R to the total flow.

In a particular blower unit, it was desired to produce a flow of 40 cfm of air at a vacuum of 8 inches of water at R, a flow of 25 cfm at 3 inches at Q, and a flow of 115 cfm at a vacuum of 3 inches at P, representing a flow total of 180 cfm discharged from D; the air flow being stated in terms of air at standard conditions. Since the pressures involved and the difference in the pressure conditions between the required performance were small, the volume flow rates were acceptably used in place of mass flow rates in the ratios determining the diffuser structure. Accordingly in a blower unit as shown and described discharging to free atmosphere the periphery of the eye I to which P discharged was selected tobe about 250 (1l5/l80 X 360); the remaining 130 (65/l80 X 360) allocated to the combined flows from Q and R. Efficient stable performance for all the three functions was attained; and even where an increased flow to 50 cfm was allowed at R, the other performances were substantially maintained, apparently by virtue of the division of the antechamber, though the eye periphery allocation then but roughtly approximated the flow percentage relations.

By way of further'example, were only the stated flow and pressure differentials involved at P and R, then with the two stage impeller discharge at the periphery of a set of blades llz without need of the louvers 31b, the dividing vanes 11x and 11y would be located to allocate respectively to each 50/ 165 X 360 and ll/l65 360 of the periphery of l.

I claim:

l. A multi-function fluid pump comprising:

a centrifugal impeller with a central intake opening;

a housing portion surrounding said impeller providing an impeller chamber having a fluid outlet, and an inner wall apertured to provide an eye opening to and aligned with the intake of said impeller;

a second housing portion forming an antechamber discharging through the eye aperture into the impeller intake, and having first and second inlets for respective pump-moved fluid streams opening to the antechamber at regions spaced angularly from each other about the axis of and radially outwardly from, said aperture;

and means dividing the circumferential space in said antechamber into at least two annular sectors each receiving a fluid stream from a respective inlet and directing each sector discharge into said eye aperture at a respective peripheral portion of said aperture, said means including a diffuser-like, fluidguiding vaned structure for said sectors.

2. A pump as described in claim 1, wherein:

said means dividing the antechamber into said sectors directs the discharge of each sector to an eye aperture peripheral portion at least roughly proportional to the respective percentage of the mass flow of fluid in the sector relative to the total mass flow intended to enter said impeller.

3. A pump as described in claim 1, including,

a second centrifugal impeller on a common shaft with the first impeller and a further housing portion therefor, disposed adjacent the antechamber oppositely from the first said chamber and having an inlet for a third moved fluid stream and an outlet to one of the two first named inlets of the antechamber.

4. A pump as described in claim 3, wherein:

said antechamber has three inlets, including at least one as a pump inlet through a circumferential wall of the antechamber into a respective said sector; and in an antechamber end wall, a series of louvered openings, into the last said sector, said series serving as another of the said three inlets and receiving the third streamdischarge from the outlet of the housing for the second said impeller.

5. As a multi-function blower for gaseous fluids, the fluid pump as described in claim 1, wherein:

said first and second inlets open through a circumferential wall of, and discharge respective inlet gas streams into, the said antechamber;

said antechamber including a second wall spaced parallel from the apertured said inner wall with said inlets opening into the space between said walls; the said second wall having a series of vaned diffusing louvers opening into one of said annular sectors; said pump including a second centrifugal impeller on a common shaft with the first impeller, and surroundedby a further housing portion,

said further housing portion providing a third inlet in communication with the intake of the respective impeller, and a discharge path for a third respective gas stream from the second impeller through said louver series to the antechamber.

6; A blower as described in claim 5, wherein:

said louvers slope inwardly to said'antechamber in the direction of rotation of the first said impeller; and

the annular sector with which said louver series is associated extends in the direction of first impeller rotation away from the respective inlet.

7. A blower as described in claim 5 for moving air in three distinct streams into respective inlets of the blower and commonly discharging the air, wherein:

said means dividing the antechamber into said sectors directs the discharge of each sector to an eye aperture peripheral portion approximately proportional to the respective percentage of the air volume flow in the sector relative to the total air volume flow intended to enter said eye aperture.

8. An air blower as described in claim 5, wherein:

a first housing member as an integrally cast structure provides the said inner wall of generally circular shape, a generally cylindrical circumferential wall extending from one side of the inner wall on one end, to peripherally surround the said first impeller, and open at its other end, a radial extension of said inner wall, a circular short flange on the other side of said inner wall but coaxial with the circumferential wall and interrupted over the locus of said extension, and vanes within the circle of, but projecting from the said inner wall axially beyond, the said flange to provide said means dividing the antechamber and the said diffuser-like structure around said eye aperture; second housing member as an integral structure provides a generally cylindrical wall portion with both ends open and one end fitted on said interrupted flange, a hollow radially outward projection diverging from the cylindrical wall portion at the said one end closed by the radial extension of said inner wall to form an inlet to one said sector; sheet metal disk, equal in diameter to and coaxially aligned with said flange, is secured on the said vanes and, as an end wall, with the cylindrical portion of the second housing member and the inner wall of the first member defines said antechamber, said disk having, over a portion of its circumference overlying the other said sector, a series of spaced notches defining tabs each twisted thereby forming said louvers; w

an end cap member providing an end wall has a rim fitted to the other end of said cylindrical portion of the second housing member, and defines therewith and with said sheet metal disk a centrifugal impel-' ler housing for impeller means including the second said impeller, said cap member having a central inlet to the said impeller means;

a disk-like housing end closure member is fitted on the open end of the first housing member to define therewith a chamber for the first said impeller, said end closure member including a bearing socket formation receiving a bearing for an impellersupporting shaft;

said members secured together as a composite blower housing by external longitudinal bolts through integral lugs on the respective peripheries of said end cap and closure members.

9. A blower as described in Claim 8, wherein:

said end closure member has said socket on the outer side thereof with a short circular flange concentric thereabout; and a motor is provided by a stator field housing fitted to the last said flange a rotor providing the said shaft with one end extending through said bearing and supporting said impellers, and a motor end bracket member supporting a bearing for the other shaft end;

said stator field housing and the bracket member being secured to said blower housing by longitudinal bolts through the end bracket member and threaded into the said end closure member thereby to form a motor-powered blower unit.

10. A pump as described in claim 8, wherein:

the circumferential wall portion of the first housing member is generally cylindrical over its major extent, and has an integral external outlet formation incomplete at the open end of the first housing member and there covered by a matching extension of the closure member, the circumferential wall portion on one side of the outlet formation curving inwardly from cylindrical as a pinch formation within the respective impeller chamber and on the other side of the outlet carried out tangentially into one side of the outlet formation;

and the shaft axis is parallel offset from the housing cylindrical axis in a direction away from the tangential portion and toward the pinch formation;

said inner wall of the first housing member being axially offset toward said antechamber along a sector within the interrupted flange adjacent said tangential wall portion to afford a discharge region axial enlargement;

whereby an approximation to a snail shell casing and discharge is provided for the first said impeller.

Claims

1. A multi-function fluid pump cOmprising: a centrifugal impeller with a central intake opening; a housing portion surrounding said impeller providing an impeller chamber having a fluid outlet, and an inner wall apertured to provide an eye opening to and aligned with the intake of said impeller; a second housing portion forming an antechamber discharging through the eye aperture into the impeller intake, and having first and second inlets for respective pump-moved fluid streams opening to the antechamber at regions spaced angularly from each other about the axis of and radially outwardly from, said aperture; and means dividing the circumferential space in said antechamber into at least two annular sectors each receiving a fluid stream from a respective inlet and directing each sector discharge into said eye aperture at a respective peripheral portion of said aperture, said means including a diffuser-like, fluidguiding vaned structure for said sectors.

2. A pump as described in claim 1, wherein: said means dividing the antechamber into said sectors directs the discharge of each sector to an eye aperture peripheral portion at least roughly proportional to the respective percentage of the mass flow of fluid in the sector relative to the total mass flow intended to enter said impeller.

3. A pump as described in claim 1, including, a second centrifugal impeller on a common shaft with the first impeller and a further housing portion therefor, disposed adjacent the antechamber oppositely from the first said chamber and having an inlet for a third moved fluid stream and an outlet to one of the two first named inlets of the antechamber.

4. A pump as described in claim 3, wherein: said antechamber has three inlets, including at least one as a pump inlet through a circumferential wall of the antechamber into a respective said sector; and in an antechamber end wall, a series of louvered openings, into the last said sector, said series serving as another of the said three inlets and receiving the third stream discharge from the outlet of the housing for the second said impeller.

5. As a multi-function blower for gaseous fluids, the fluid pump as described in claim 1, wherein: said first and second inlets open through a circumferential wall of, and discharge respective inlet gas streams into, the said antechamber; said antechamber including a second wall spaced parallel from the apertured said inner wall with said inlets opening into the space between said walls; the said second wall having a series of vaned diffusing louvers opening into one of said annular sectors; said pump including a second centrifugal impeller on a common shaft with the first impeller, and surrounded by a further housing portion, said further housing portion providing a third inlet in communication with the intake of the respective impeller, and a discharge path for a third respective gas stream from the second impeller through said louver series to the antechamber.

6. A blower as described in claim 5, wherein: said louvers slope inwardly to said antechamber in the direction of rotation of the first said impeller; and the annular sector with which said louver series is associated extends in the direction of first impeller rotation away from the respective inlet.

7. A blower as described in claim 5 for moving air in three distinct streams into respective inlets of the blower and commonly discharging the air, wherein: said means dividing the antechamber into said sectors directs the discharge of each sector to an eye aperture peripheral portion approximately proportional to the respective percentage of the air volume flow in the sector relative to the total air volume flow intended to enter said eye aperture.

8. An air blower as described in claim 5, wherein: a first housing member as an integrally cast structure provides the said inner wall of generally circular shape, a generally cylindrical circumferential wall extending from one side of the inner wall on one end, to peripherally surround the said first impeller, and open at its other end, a radial extension of said inner wall, a circular short flange on the other side of said inner wall but coaxial with the circumferential wall and interrupted over the locus of said extension, and vanes within the circle of, but projecting from the said inner wall axially beyond, the said flange to provide said means dividing the antechamber and the said diffuser-like structure around said eye aperture; a second housing member as an integral structure provides a generally cylindrical wall portion with both ends open and one end fitted on said interrupted flange, a hollow radially outward projection diverging from the cylindrical wall portion at the said one end closed by the radial extension of said inner wall to form an inlet to one said sector; a sheet metal disk, equal in diameter to and coaxially aligned with said flange, is secured on the said vanes and, as an end wall, with the cylindrical portion of the second housing member and the inner wall of the first member defines said antechamber, said disk having, over a portion of its circumference overlying the other said sector, a series of spaced notches defining tabs each twisted thereby forming said louvers; an end cap member providing an end wall has a rim fitted to the other end of said cylindrical portion of the second housing member, and defines therewith and with said sheet metal disk a centrifugal impeller housing for impeller means including the second said impeller, said cap member having a central inlet to the said impeller means; a disk-like housing end closure member is fitted on the open end of the first housing member to define therewith a chamber for the first said impeller, said end closure member including a bearing socket formation receiving a bearing for an impeller-supporting shaft; said members secured together as a composite blower housing by external longitudinal bolts through integral lugs on the respective peripheries of said end cap and closure members.

9. A blower as described in Claim 8, wherein: said end closure member has said socket on the outer side thereof with a short circular flange concentric thereabout; and a motor is provided by a stator field housing fitted to the last said flange , a rotor providing the said shaft with one end extending through said bearing and supporting said impellers, and a motor end bracket member supporting a bearing for the other shaft end; said stator field housing and the bracket member being secured to said blower housing by longitudinal bolts through the end bracket member and threaded into the said end closure member thereby to form a motor-powered blower unit.

10. A pump as described in claim 8, wherein: the circumferential wall portion of the first housing member is generally cylindrical over its major extent, and has an integral external outlet formation incomplete at the open end of the first housing member and there covered by a matching extension of the closure member, the circumferential wall portion on one side of the outlet formation curving inwardly from cylindrical as a pinch formation within the respective impeller chamber and on the other side of the outlet carried out tangentially into one side of the outlet formation; and the shaft axis is parallel offset from the housing cylindrical axis in a direction away from the tangential portion and toward the pinch formation; said inner wall of the first housing member being axially offset toward said antechamber along a sector within the interrupted flange adjacent said tangential wall portion to afford a discharge region axial enlargement; whereby an approximation to a snail shell casing and discharge is provided for the first said impeller.