US3924963A

US3924963A - Turbomachine

Info

Publication number: US3924963A
Application number: US401403A
Authority: US
Inventors: Dieter G Zerrer
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-09-27
Filing date: 1973-09-27
Publication date: 1975-12-09
Anticipated expiration: 1992-12-09
Also published as: DE2444964A1

Abstract

A turbomachine has at least one novel integral runner assembly formed by a centripetal inducer portion and a centrifugal impeller portion, both of which include a plurality of circumferentially spaced vanes in the vicinity of each periphery. An intermediate shroud separates the vanes of each portion and, together with a forward and rearward shroud, establishes a space through which fluid flow in a generally oblique meridional flow pattern is conducted from the trailing edge of an centripetal inducer vane to the leading edge of a centrifugal impeller vane. The integral runner assembly is disposed within a housing including means to present a radial flow of fluid for entry into the centripetal inducer portion and additional means at the outlet of the integral runner assembly to remove all tangential vector components of flow in order to impart to the flow an axial direction.

Description

United States te t 1191 111] 3,

Zerrer 5] Dec. 9, 1975 TURBOMACHINE 843,638 4/1939 France 415/143 7 242,855 11/1925 United Kingdom 415/198 [76] Inventor Zerrer Box 25,109 1907 United Kingdom 415/219 c Easton, 21601 1,279,260 11/1961 France 415/198 [22] Filed: Sept. 27, 1973 [21] Appl. N0.: 401,403 Primary Examiner-Henry F. RaduaZO Attorney, Agent, or Firm-Pennie & Edmonds [52] US. Cl 415/143; 415/198; 415/219 C;

417/423 R [51] Int. Cl. F04D 17/02 7 TRQ [58] Field of Search 415/120, 198, 219 C, 215, [5 ABS CT 415/143 A turbomachine has at least one novel integral runner assembly formed by a centripetal inducer portion and [56] References Clted a centrifugal impeller portion both of which include a UNITED STATES PATENTS plurality of circumferentially spaced vanes in the vi- 846,971 3/1907 Akimoff 415/120 cinity of each periphery. An intermediate shroud sepa- 854,012 5/1 0 Akit fi' 4 rates the vanes of each portion and, together with a gavldsonk i gfigz forward and rearward shroud, establishes a space awacze l 1,363,315 mm M. 417/422 ggg gg y 'gggg g1 3153 3 5535 gg lggg ggfg 2,265,806 12/1941 Goldschmied 415/198 f P l d 1 g g 2,395,704 2/1946 Wislicenus 415/198 0 P m ucer the ca mg edge Ofa 2,422,763 6/1947 Wislicenus... 260/268 centrlfilgal Y f' {unner assem- 2,471,892 5/1949 Price 1 415/120 bly 1S dlsposed Wlthm a houslng lncludmg means to 2,985,108 5/1961 s e; et a1, 415/120 present a radial flow of fluid for entry into the centrip- 3,069,071 12/1962 Carlson 415/1 16 etal inducer portion and additional means at the outlet 3,1 8 9/ 3 Sto et 4l5/l20 of the integral runner assembly to remove all tangen- 3,305,l65 2/ 1967 e y 415/211 tial vector components of flow in order to impart to 3,584,968 6/1971 Keith 415/215 the flow an axial direction FOREIGN PATENTS OR APPLICAT1ONS 813,337 2/1937 France 415/120 16 Claims, 10 Drawing Fi res US. atsnt Dec. 9, 1975 Sheet 1 of6 3,924,963

US. atent Dec. 9, 1975 Sheet 2 of6 3,924,963

atsnt Dec. 9, 1975 Sheet 4 of 6 3,924,963

US. Patent Dec. 9, 1975 shw 6 of6 3,924,963

TURBOMACHINE The invention relates to turbomachines having improved structural and operational characteristics. The turbomachine is of the type having at least a single stage radial flow runner comprising a multiplicity of vanes or fluid reaction surfaces in an axial flow housing. Particularly, the runner of at least one stage is arranged to provide a centripetal inducer portion integrally combined with a centrifugal impeller portion to form a single radial inward-outward flow runner (hereinafter integral runner). The turbomachine of the present invention achieves a novel flow pattern in the machine through the combination with the integral runner of a stationary annular diffusor cascade arranged downstream of the integral runner. As an incident to the novel flow pattern, the turbomachine provides that the fluid, either a liquid or gas, undergoes an increase in total pressure through each stage of the turbomachine. This pressure increase is substantially greater than that obtained by solely an outward flow impeller runner of the prior art having equal diameter and flow rate and moving at an equal rotational speed.

Without any limiting intent, the turbomachine of the present invention may have application as a fan, a blower, or a turbine pump having no more than approximately medium head per stage.

The prior art includes turbomachines including runners providing in combination a centripetal impeller and a centrifugal impeller. While the prior art devices of this type superficially resemble the integral runner of the present invention, the intended function and the actual effects of the integral runner are quite distinct from and not satisfied by the prior art devices.

The prior art devices of the above type are easily contrasted with the integral runner of the present invention. The prior art devices suffer from certain disadvantages and generally are considered unsuitable for use in turbomachines intended for the purpose of increasing the pressure in a fluid. More particularly, in centripetal type impellers there is a tendency that the centrifugal forces counteract the pressure generating capability of the curved vanes. At flow volumes less than the design flow, the pressure decreasing effect of the centrifugal forces acting on an inward flowing fluid is particularly pronounced. The pressure gain by the vane action may be overcome, resulting in a net pressure loss. Thus, the purpose of the turbomachine is obviated.

It is generally recognized that, in pressure increasing turbomachines, it is advantageous to have an outward flow. In addition to the static pressure rise caused by the flow deflecting action of the vanes, the centrifugal forces acting on the outward flowing particles contribute to the increase in static pressure. The centripetal inducer of the present invention serves to improve the pressure producing capabilities of the associated centrifugal impeller rather than to produce substantial pressure increase in the flow passing through it. ln contrast, the centripetal impeller of the prior art is intended to cause a substantial pressure increase in the flow passing through it. In the prior art devices, the centripetal impeller and the centrifugal impeller are treated as independent pressure producing components, combined in an additive manner. Each could operate independently.

such that, over a considerable part of the turbomachines operating range, and particularly at flows below design capacity, the centripetal inducer discharges the flow into the inlet of the centrifugal portion at an unchanged or somewhat reduced pressure. Nevertheless, there is capability of generation of static pressure far in excess of that obtainable with a single centrifugal rotor of equal diameter and flow rate and rotating at the same speed.

The centripetal inducer accomplishes these purposes by minimizing the mismatch between flow direction and the impeller vane direction at the impeller inlet. The centripetal inducer enables the centrifugal impeller to operate with minimum shock loss over substantially all of the turbomachines capacity range.

There is no recognition in the prior art of the hydrodynamic oneness of the integral runner of the present invention. Whereas in many known prior art devices, the discharge of fluid from the centripetal impeller in meridional projection follows generally a U-shaped path from the trailing edge for entry at the leading edge of the centrifugal impeller with the flow direction being purely axial in the impeller eye, the meridional flow direction in the present turbomachine is along approximately a diametric course from the trailing edge of the centripetal inducer vanes to the leading edge of the centrifugal impeller vanes. Thus, the centripetal inducer and centrifugal impeller are designed in a manner such that the flow in meridional projection does not follow a U-shaped path in moving from the centripetal inducer to the centrifugal impeller. The integral runner is designed in a manner to preclude satisfactory independent operation of either component.

A further shortcoming of the prior art is in the use of volute or scroll type casing elements through which the flow approaches the centripetal runner with an inward spiral motion having pronounced tangential velocity components. In some prior art proposals, the direction of the tangential fluid admission is opposite to the runner peripheral velocity, while in others it agrees with the runner rotation. Either approach is impractical. In the first case, the counte r-rotation of the runner against the tangentially entering fluid prevents the fluid from distributing itself uniformly around the runner periphery. In the second, although the co-rotation assists in drawing the fluid into the scroll type inlet casing, the fluid would have to reverse its direction at the vane tips by nearly in order to enter the vane channels since the centripetal runner must have forwardly curved vanes. Apart from the impossiblity of this abrupt reversal, it is generally recognized among those skilled in the art that fluid co-rotation in the runner approach diminishes the pressure generating capacity of any type of turbomachine runner. However. in multistage compressors and high head per stage pumps the use of tangential admission is unavoidable since in such machines the high-velocity discharge whirl of the fluid coming from the preceding centrifugal impeller cannot be removed by statinary straightener vanes without causing the flow to choke in the straightener channels.

The turbomachine of the present invention successfully overcomes the objections, difficulties, and disadvantages inherent in volute type casings by providing an annular inlet passage upstream of and co-axial with the centripetal inducer. It is through this passage that the fluid approaches the periphery of the centripetal inducer in uniform distribution and in a purely axial di rection, i.e., without tangential velocity components. An annular guide baffle radially adjacent the intermediate shroud member deflects the flow inwardly into the centripetal inducer. The guide baffle also serves as a wall separating the low pressure inlet region and the high pressure discharge region. The guide baffle may be attached to the tubular outer casing and thus stationary or it can take the form of a radial extension of the intermediate shroud member between the centripetal inducer and centrifugal impeller portions to rotate with the integral runner and form a running clearance with the outer casing. This will be discussed below. The prior art also includes axial flow inducers to improve the operating characteristics of the centrifugal impeller. These inducers have the general appearance of a propeller or screw-type auger. The prior art axial inducer has application primarily in pumps for the purpose of suppressing cavitation rather than to generate a higher overall static pressure by the runner.

It is known by those skilled in the art that the pressure generated by an outward flow runner of given design is determined by the runner diameter and by the speed at which the runner is rotating. In a practical situation the magnitudes of these two parameters have definite limits dictated by considerations of structural strength, permissible weight and size, available prime mover speeds, and other factors. Thus, the pressures obtainable from a single outward flow runner of given design are clearly circumscribed. In those applications which require pressures higher than can be produced by a single outward flow runner under a given set of parameters, it is necessary to utilize a multistage machine having two or more outward flow runners arranged in series on the same drive shaft. In a multistage turbomachine each outward flow runner after the first one receives its inlet flow from the discharge of the preceeding outward flow runner. However, this transfer of fluid from one outward flow runner to a following runner on the same axis cannot be effected in a direct manner. In this connection, the fluid which leaves the first runner at its outer periphery with a high velocity having radial and circumferential components must enter the following runner eye at a much lower velocity and have essentially axially components of direction. Stationary flow guiding apparatus, known as interstage diffusers and return channels, has to be interposed between successive runners of a multistage turbomachine in order to bring about the changes in flow velocity and flow direction necessary for the transfer of fluid from one runner to the next. The use of these interstage flow guiding devices entails considerable complexity of design and results in substantial increase in space requirements and weight. It also contributes to the hydraulic losses in the turbomachine in the form of friction, turbulence, and clearance leakage losses. The incorporation of this structure into the design increases both the cost of construction and the cost of operation of the machine.

The turbomachine of the present invention having two vane carrying runners which are structurally combined into a single inward-outward flow runner, as described more particularly hereinafter, is capable of producing two-stage action in a single stage. Therefore, the stationary interstage flow guiding apparatus in the prior art two-stage devices is obviated.

However, it is to be noted that the inward-outward flow runners of the turbomachine of the present invention may be staged, as required. Such multistaging ac tually is facilitated by the fact that the need for returning the discharge flow of the centrifugal impeller to the inlet eye of small diameter and axial access direction of prior art devices is obviated. The present invention requires only a radial inward flow at the inlet of the following runner.

The two-stage machine employing two radial inwardoutward flow runners according to the present invention will generate pressures comparable to those achieved by a four-stage machine of prior art design having four outward flow runners of equal diameter and operating at the same rotational speed and flow rate. However, instead of the three required interstage diffuser and return channel arrangements, the twostage turbomachine of the present invention requires only a single diffuser.

By the present invention there is provided a turbomachine having improved features of design and construction which is capable of producing static pressure substantially increased over that pressure obtained from a conventional turbomachine stage of the same diameter and operating at the same speed and flow rate.

In a slightly different light, as should be apparent, the device of the present invention is capable of achieving required pressure increase with a substantially smaller diameter runner which shall operate at the same speed and handle the same flow of fluid as the conventional turbomachine stage. As an incident to the smaller runner diameter and lower tip speed the noise level generated by the runner is reduced as is the machine diameter. Further, the runner will have a smaller moment of inertia requiring a lower motor starting torque.

In accordance with this aspect of the present invention, there is provided a novel integral runner having a centripetal inducer and an impeller section directly cooperable to achieve a flow pattern which assists in the result of an increase in fluid pressure through the machine. The integral runner is disposed in an axial housing. The housing includes guide baffle structure radially adjacent the intermediate shroud member to divert the fluid flow from a predominantly axial direction to a predominantly radial direction for entry to the centrip etal inducer portion.

As a further aspect, the present invention contemplates one or more integral runners to be staged in an axial housing to achieve pressure increase. In this form of the present invention which is actually facilitated by the flow pattern through the machine the integral runners are spaced apart and an interstage diffusor is disposed therebetween. The diffusor including a plurality of vanes serve to reduce the absolute velocity of the fluid flow and increase static pressure as well as to act upon the fluid to remove all tangential velocity components so that the fluid leaves the diffusor vanes in purely an axial direction.

While the turbomachine of the present invention is capable of achieving required pressure increase, as stated, by a smaller diameter runner the turbomachine also is capable of achieving the pressure increase through the use of approximately one-half the number of stages (runners) of conventional turbomachines of equal runner diameter and speed. The operational result achieved by the present turbomachine is most evident from the plot of the same and the comparison with the plots of two prior art turbomachines, i.e., plot representations II and III (see FIG. 8). As may be appreciated, the design point pressure of the present turbomachine is over twice that of the design point pressure of turbomachine II and slightly less than twice that of the design point pressure of turbomachine III. All three single stage turbomachine have the same runner diameter and rotational speed.

Since the integral runner of the present invention is capable of meeting pressure requirements utilizing substantially one-half of the stages required by the prior art, the present invention obviates the need for added interstage diffusors and, accordingly, not only reduces cost, space, and weight requirements but also reduces the extent of hydraulic losses in the turbomachine in the form of friction, turbulence, and clearance leakage losses introduced by the staging apparatus.

As a further aspect of the present invention, the integral runner provides a novel fluid flow pattern through the turbomachine. More particularly, the flow pattern follows generally a diametric course across the center line of the turbomachine from the trailing edge of a centripetal inducer vane to the leading edge of a centrifugal impeller vane.

A further aspect of the present invention contemplates an integral runner which has particular application in small turbomachine. In this connection, the shaft carrying the integral runner does not extend through the flow carrying center portion. In this connection, the shaft does not take up too much of the space available for the flow.

An additional aspect of the present invention resides in the disposition of the inlet opening to the first stage integral runner. To this end, the inlet opening is radially inward from all directions. This form of inlet also provides that the fluid flow approaching the periphery of the centripetal inducer is substantially free from tangential velocity components. Particular application may be in the yield of submersible pumps.

In yet a further aspect of the present invention, there is provision that all rotating stages of the turbomachine are axially inserted into and removed from the stationary housing. To this end, the rotating stages are joined in order to obviate the use of stationary casing components for spacing. The rotating stages provide running clearance with guide baffle and diffusor vanes and a demarcation between areas of differing pressure is maintained. A front and rear casing member provide support for required bearing members.

The efficiency of the single-stage blower of the present invention is equivalent to that of comparable conventional single-stage blowers. Since in multi-stage machines the overall efficiency is the product of the stage efficiencies, and since the turbomachine of the present invention will produce a given pressure with one-half the number of stages, the overall efficiency of a multistage turbomachine of the present invention will be superior to that of a conventional turbomachine producing the same pressure.

A further aspect of the present invention resides in the fact that the head-capacity curves generated by a turbomachine stage cannot be reproduced by any prior art type of turbomachine stage, radial or axial, conforming to the same set of design parameters such as a set including runner diameter, rotational speed, static pressure and outlet velocity; or a set including runner diameter, rotational speed, flow rate and outlet velocity.- The present invention thus provides a type of turbomachine covering a flow-pressure field in a novel and distinct manner thereby opening the way for new applications and yielding solutions to application problems that heretofore could not be solved under a given set of parameters.

There has thus been outlined rather broadly the more important features of the present invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the present invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of the invention. It is important, therefore, that the claims be regarded as including said equivalent construction and do not depart from the spirit and scope of the invention.

In order that the invention be more readily understood the same will now be described in conjunction with the accompanying drawings, in which:

FIG. 1 is a view in elevation, partly in section, of a multistage turbomachine and the novel integral runner assembly;

FIG. 2 is a view similar to FIG. 1 yet illustrating a single stage turbomachine;

FIG. 3 is a view similar to, yet a slight variation of, the single stage turbomachine of FIG. 2;

FIG. 3A is a view in front elevation of the turbomachine of FIG. 3 illustrating the inducer vanes and inner inlet casing;

FIG. 3B is a view in rear elevation of the turbomachine of FIG. 3 illustrating the drive mechanism for the drive shaft and the stationary annular diffusor cascade;

FIG. 4 is a view in section illustrating a multistage turbomachine similar to the turbomachine of FIG. 1;

FIG. 5 is a view in section illustrating a turbomachine having a radial inlet to the first stage integral runner;

FIG. 6 is a view in section illustrating an integral runner having an open flow path between inducer and impeller sections;

FIG. 7 is a perspective view of the integral runner; and

FIG. 8 is a plot of operation of the turbomachine of the present invention andcertain prior art turbomachines, the plots locating the design point of the several turbomachines.

The turbomachine illustrated in FIG. 1 is of multistage construction, i.e., the apparatus includes at least a pair of integral runners of the present invention. The integral runners are disposed between an inlet duct 12 and an outlet duct 14. The fluid entering at the inlet is subjected to the operating conditions of the integral runners and associated structure and undergoes an increase in static pressure during flow through a housing from the left to right in FIG. 1.

The housing is generally indicated by the numeral 16 and includes a plurality of

tubular duct sections

18, 20 and 22 comprising an inlet outer casing, an interstage outer casing and a discharge outer casing, respectively. These casing members, and there may be a plurality of interstage components, as required, are axially arranged one to the other.

Each interstage outer casing carries an annular flange at opposed ends. The flange facilitates mounting the duct sections to one another and to the inlet and outlet ducts which carry a flange construction on one end only. Any particular mechanical mounting structure may be employed for this purpose.

An inlet inner casing 24 is disposed within and in coaxial relation to the inlet outer casing. The inlet inner casing includes an inwardly flared downstream end 25. A plurality of members 26 are carried by the inlet outer casing and extend inwardly of the casing at spaced circumferential positions. Preferably, two or more members 26 are provided to support the inlet inner casing. As best seen in FIG. 3A, four members are provided for this purpose. Each member is formed by a substantially flat plate. The inner edge of each plate may be formed to complement the contour of the inlet inner casing. Each member may be welded or by any other convenient means mechanically joined to the inlet inner casing at the junction.

The members, in addition to providing support for the inlet inner casing, also assist in eliminating undesirable tangential velocity components in the flow of entering fluid and guide the fluid in a purely axial direction toward the first of the integral runner assemblies.

FIG. 1 illustrates a pair of integral runners denoted generally by the

numerals

28,30. The integral runners are supported for rotation about the axis of the duct members. To this end, the integral runner 30 is supported by a shaft 32. The integral runner 28 is supported by an overhung section 34 of the shaft.

A pair of elements support the shaft components within the duct sections. In this connection, an inner casing 36 supports the forward end and an inner casing 38 supports the rearward end of shaft 32. The inner casing 36 may be referred to as an interstage inner casing because of the disposition between the

integral runners

28 and 30. A plurality of diffusor vanes 40 positioned circumferentially support the interstage inner casing in coaxial relation to the housing. One circumferential group of diffusor vanes supports an individual inner casing. The diffusor vanes are carried by a

duct section

20, 22 to project toward the axis thereof for connection with the

inner casings

36, 38.

The faces of the diffusor vanes are somewhat curved. The vane outline and spacing may be seen more clearly in FIG. 3B. The diffusor vanes, in addition to the support function, provide operational functions in their cascade relation as will be discussed.

The interstage inner casing 36 includes a cylindrical body 42. The body terminates in an inwardly flared downstream end 44. A disc shaped wall 46 having a central aperture 48 is disposed within and perpendicular to the walls of the body 42.

The inner casing 38 which may be referred to as a discharge inner casing is formed generally similar to the interstage inner casing. Thus, the discharge inner casing 38 includes a cylindrical body 50 having a downstream truncated wall portion 52. A disc shaped wall 54 having a central aperture 56 is disposed within and perpendicular to the walls of the body 50.

Shaft 32 is received through the central wall apertures and supported by bearing

elements

58, 60. The bearing elements are mounted by the

walls

46, 54. Shaft section 34 is carried by the bearing 58. The shaft projects forwardly of the duct sections toward the inlet 12.

A hub 62 mounts the intergal runner 28. A hub 64 mounts the intergal runner 30. Each integral runner is positioned relative to other intergal runners within the turbomachine for rotation. To this end, intergal runner 28 is positioned by the bearing 58 at one end and a nut and washer assembly 66 at the other end. The intergal runner 30 is positioned on the shaft 32 by means of a pair of collars 68 secured to the shaft.

Each intergal runner includes a centripetal inducer portion 70 and a centrifugal impeller portion 72. The first stage centripetal inducer 70, i.e., the inducer of integral runner 28, centripetal includes at the inlet a plurality of blades or vanes 74. Preferably, the vanes are curved. Centripetal inducer sections of subsequent integral runners likewise include at the inlet a plurality of vanes 76. As with vanes 74, the vanes 76 also are preferably curved. A plurality of contoured vanes 78 are disposed at the outlet of the centrifugal impeller portrons.

The outer ends of vanes 74(or 76), and 78 are attached to a front shroud 80 and a back shroud 82, respectively. The inner ends of the vanes are attached to an intermediate shroud 84. Both the front and back shroud members are attached to the respective hubs, as illustrated in FIG. 1.

A guide baffle 104 is positioned axially within the fluid flow path. The baffle may be supported between the flanges of the inlet and interstage outer casings. The baffle includes a central cylindrical opening and provides a face that may be normal to the flow but preferably the face is inclined to the flow as illustrated in FIG. 1. The central opening permits a running clearance with the intermediate shroud member 84. A second guide baffle 108 similarly formed is disposed between the flanges of the interstage and discharge outer casings. The guide baffles together with the flared surfaces 25 and 44 define an inlet opening to the several integral runners and also serve the important function of deflecting the axial fluid flow to one of predominantly radial path.

A motor -serves as a prime mover for rotating the shaft 32 and the overhung section 34 as well as the integral runners. To this end, the motor includes power shaft 92. A pulley wheel 94 is carried by the shaft while a second pulley wheel 96 is carried by shaft 32. A belt 98 including a plurality of individual belt elements drivingly connects the motor shaft 92 and runner shaft 32.

The motor is mounted by the discharge outer casing 22 at or near the outlet duct 14. A duct 100 encloses the belt. The duct is supported by the truncated wall portion of the discharge inner casing and by the discharge outer casing 22. The turbomachine is supported by base members 102.

In operation, fluid is drawn into the turbomachine and flows past the support members into the annular region 110. The flow, because of the support members 26, is in an axial direction and contains no tangential velocity components. The flow is diverted from a purely axial direction by means of the guide baffle 104 (and 108 with regard to the second integral runner assembly) to predominantly a radial direction for entry into the centripetal inducer 70. Flow of fluid passes the guide baffle and flared end 25. The guide baffle 104 (and 108), as may be apparent, also serves to separate a low pressure inlet flow to the integral runner assembly from high pressure outlet flow exiting the centrifugal impeller 72 of the integral runner.

The flow passing the circumferentially spaced vanes 74 traverses the centripetal inducer portion by following generally a diametric course through the flow area from the trailing edge of a centripetal inducer vane to the leading edge of a centrifugal impeller vane. The intermediate shroud member separates the centripetal fluid flow passing between the vanes 74 from the centrifugal fluid flow passing from the integral runner through the vanes 78.

Flow of fluid into and through the turbomachine is represented by the several directional arrows in the figure.

Flow of fluid continues toward the second integral runner. The flow follows a course past the cascade diffusor vanes 40. As will be brought out, the diffusor vanes have a dual effect on the flowing fluid. On the one hand, the vanes serve to increase static pressure of the fluid by reducing the absolute velocity of the fluid. On the other hand, and as an inherent consequence thereof, the diffusor vanes serve to remove all tangential velocity components from the flow. In this connection, the fluid leaves the area of the cascade diffusor vanes in a purely axial direction. The fluid is now in a suitable condition for entry into the second stage centripetal inducer. In a manner similar to baffle guide 104, the baffle guide 108 acts upon the flow of fluid to cause an alteration to a predominantly radial direction. The flow of fluid enters the second stage centripetal inducer through the opening defined by the baffle 108 and the flared end 44 of the interstage inner casing.

The fluid in the second stage is acted upon in a manner similar to the action of the first stage. Upon exiting the second stage, the fluid flow is acted upon by a further cascade of diffusor vanes 40. The truncated wall of the discharge inner casing 52 in cooperation with the wall of the discharge outer casing acts as an annular diffusor to impart to the fluid a further gain in static pressure prior to exiting the turbomachine by the outlet duct 14.

The embodiment of FIG. 2 generally resembles the embodiment of FIG. 1. The FIG. 2 embodiment, however, represents a single stage unit. In this figure, components, which duplicate those components of FIG. 1 are identified by like references.

In FIG. 2 the outer casing is formed of a single cylindrical member 150. A pair of

flanged rings

152, 154 are slideably received at opposite ends of the outer casing. Preferably, the flanged ring 152 is removably fastened to the outer casing. The flanged ring 154 may be permanently attached to the outer casing. An inlet and outlet duct (not shown) may be attached to the outer casing by mounting the same to the flanged rings in any convenient manner.

A plurality of support members 26 are carried by the flange ring 152. The members are of flat plate construction yet differ slightly from the plates 26 in overall shape. In this connection, the plates generally are triangular. They are carried by the flanged ring 152 and support both the inlet inner casing 24 and the guide baffle 104.

The integral runner 28 is similar to the runner of the FIG. 1 embodiment. It distinguishes, however, in the construction of the intermediate shroud member 156 which connects the centripetal inducer and centrifugal impeller portion of the integral runner. To this end, the member 156 includes a radial extension 158. The extension terminates adjacent the wall of the outer casing 150 and assists the guide baffle 104 in partitioning the low pressure inlet region 160 and a high pressure discharge region 162.

The integral runner 28 is carried by hub 62 which, in turn, is carried bythe extension 34 of shaft 32. Suit able mechanical fasteners 164 join the hub to the back shroud 82 of the runner.

The inner casing 50 is supported by cascade diffusor vanes 40. The casing substantially duplicates the discharge inner casing of FIG. 1. To this end, it comprises a forward cylindrical portion 166, an end wall 168 including a central opening, and a rear truncated portion 170. A bracket 172 carried within the inner casing by 10 means not shown supports a pair of

bearings

174, 176. Shaft 32 is rotatably mounted by the bearings.

A base element 178 supports the single stage unit.

FIG. 3 illustrates a slight variation of the turbomachine of FIG. 2. The difference may be appreciated from the following discussion. In the FIG. 3 embodiment, the support member 26" mounts only the guide baffle 104. The inlet inner casing 200 is connected to or integral with the front shroud 202 of runner assembly 28. The rear portion inner casing 50 is cylindrical like the forward portion 166.

FIG. 4 is illustrative of a typical crosssection of a multistage turbomachine in an axial flow casing 250. In the embodiment, a shaft 32 is illustrated as supporting a plurality of three

integral runners

252, 254, and 256. The shaft is supported by a pair of bearings, the rear bearing being shown at 258. It has been found that two bearings are sufficient to support the runner shaft and consequently, since this structure is all that need be connected to the outer casing, it is possible in a multistage machine, such as FIG. 4, to form all inner casings excepting the first and last as cylindrical spacing bodies of impeller diameter. As illustrated, the back shroud 260 of each integral runner is connected to an axial extension 262 of the front shroud 264 of a following centripetal inducer portion of an integral runner. These inner casings provide a running clearance with the vanes 266 of the cascade diffusors. The diffusors are attached to the outer casing only.

The guide baffle 268 and intermediate shroud member 270 likewise provide a running clearance. The dimension of each essentially corresponds to the dimensions of the cascade diffusor vane and the inner casing.

The inlet inner casing 272 is supported by the support members 26. The inlet inner casing is substantially dish-shaped and carries a neck portion 174 which projects from the base. The neck carries the front bearing 276.

The turbomachine of FIG. 4 represents an overall configuration in which an integral runner comprising the rotating components of all stages may be axially inserted into or removed from a stationary casing. As-

. sembly and disassembly can be accomplished after one of the two bearing-carrying inner casings at either end of the turbomachine has been removed. In this manner, the complicated procedure of stacking integral runners and stationary inner components alternately along the shaft is obviated. Manufacturing and maintenance is facilitated by this construction.

A variation of the construction of, for example, FIG. 1, is illustrated in FIG. 5. The turbomachine of FIG. 5 provides a radial flow inlet 300 to a centripetal inducer 302 of integral runner 304. This structure has many applications such as in a class of submersible pumps to be installed vertically in a well or form of tank. The pumping of water, oil, etc., is contemplated.

The structure comprises an outer casing 310 and an inner casing 312. The inner casing provides a wall 314 having a central open neck portion 316. A shaft 320 is supported for rotation within the neck by a bearing 322 and extends forwardly to mount the integral runner 304. An inlet casing 324 comprises a guide baffle 326 and circumferentially spaced projections 300 jutting out therefrom in a substantially axial direction. The projections are preferably in the form of flow guide vanes. The spaces between the projections are openings for the admission of fluid. An intermediate shroud member 328 separates the centripetal inducer and cen- 1 1 trifugal impeller portion of the integral runner for the reason as previously discussed.

The inlet flow of fluid to the centripetal inducer is from all directions and radially inward toward the flow carrying center portion. Thus, the inlet flow is free of tangential velocity components.

FIG. 6 illustrates a variation of the structure of FIG. 4. The particular distinction is in the construction of integral runners 350 and the manner of support by a split shaft 352. Thus, the flow carrying portion, like the integral runner structure of FIG. is open. A design of this type is particularly adapted for use in small machines in which the shaft would take up too much of the available flow space. A further distinction is in the form of centripetal inducer 354 and centrifugal impeller vane 356 including inner and outer vane edges which are not parallel to the axis of the drive shaft 352.

From the foregoing, it will be seen that, in accordance with the present invention, there is provided a turbomachine which satisfies the objects of the invention and provides advantages not heretofore achieved in the turbomachine art.

Having described the invention with particular reference to the preferred forms thereof, it will be obvious to those skilled in the art to which the invention pertains after understanding the invention, that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the claims appended hereto.

Having described the invention, 1 claim:

1. A pressure increasing turbomachine comprising a stationary housing having an elongated generally cylindrical chamber with a fluid flow intake at one end and a fluid flow discharge at the other end, a shaft, means for mounting said shaft for rotation within and concentric to the housing wall, said shaft adapted to be connected to a prime mover to impart rotation to the shaft, at least one fluid-dynamically integral runner including a centripetal inducer and a centrifugal impeller wheel portion, each portion comprising a plurality of circumferentially spaced fluid flow energy increasing vanes within the vicinity of the periphery of said wheel portions and an intermediate shroud member separating the vanes of one portion from the other, means for mounting said runner for co-rotation on said shaft, means including stationary straightening vanes upstream of said centripetal portion for drawing a fluid flow substantially without tangential velocity components radially into said centripetal inducer portion, and stationary means for guiding said flow from said centrifugal impeller portion axially through said housing, said stationary guide means including a plurality of stationary guide vanes arranged for substantially axial through-flow downstream of said centrifugal impeller portion.

2. The turbomachine of claim 1 including a plurality of runners mounted on said shaft for co-rotation and means separating said runners axially on said shaft, said separating means defining with said housing an interstage flow channel, and said stationary guide means for impeller flow being disposed in said channel for removing tangential velocity components from said flow.

3. The turbomachine of claim 2, wherein said separating means includes an inner housing member, said stationary guide means mounting said inner housing member within said housing.

4. The turbomachine of claim 2 wherein said separating means includes an axial extension connecting one runner to another runner.

5. The turbomachine of claim 2 wherein said stationary guide means for impeller flow comprise a plurality of circumferentially spaced blades, said blades being mounted to said housing to project radially inwardly.

6. The turbomachine of claim 5 wherein said separating means includes an inner housing member, said stationary guide means mounting said inner housing member within said housing.

7. The turbomachine of claim 1 wherein said means for drawing a fluid flow into said centripetal inducer portion further comprises an inlet inner casing, means mounting said inlet casing in coaxial relation to said housing, and an annular baffle element, means mounting said element within said housing to project toward said intermediate shroud member, said baffle element diverting said fluid to predominantly a radial direction and in cooperation with said intermediate shroud member providing demarcation between a pressure zone at said centripetal inducer inlet and a higher pressure Zone at said centrifugal impeller outlet.

8. The turbomachine of claim 7, said stationary straightening vanes providing a mounting for said inlet inner casing.

9. The turbomachine of claim 7 including a forward shroud member, said forward shroud member mounting both said inducer vanes and said inlet inner casing on said shaft 10. The turbomachine of claim 1 including a rearward shroud member, said rearward shroud member mounting said impeller vanes on said shaft.

11. The turbomachine of claim 1 including a forward and rearward shroud member, said forward and rearward shroud members formed as disc-shaped plates mounting said centripetal inducer and centrifugal impeller vanes to said shaft and defining the extremes of a space within said runner, said intermediate shroud member cooperating therewith to provide a multiplicity of fluid paths directed substantially obliquely through said space from a centripetal inducer flow deflecting vane to a centrifugal impeller flow deflecting vane.

12. The turbomachine of claim 8 wherein said stationary straightening vanes include plate-like members arranged circumferentially about said housing and extending axially toward said annular baffle element.

13. The turbomachine of claim 1 wherein said means for drawing fluid flow into said centripetal inducer portion includes a guide baffle having a surface directed generally toward the axis of said centripetal inducer portion, circumferentially spaced projections jutting out from said surface is substantially an axial direction and defining a plurality of inlet openings arranged around the periphery of said centripetal inducer portion for admission of fluid thereto in substantially a radial direction.

14. The turbomachine of claim 1 comprising a runner in which the internal space formed by said centripetal centrifugal inducer and impeller portions is open for unobstructed crosswise fluid flow from said centripetal inducer vanes to said centrifugal impeller vanes.

15. The turbomachine of claim 1 including an inner housing member arranged in downstream position adjacent said centrifugal impeller portion, means mounting said inner housing member within said housing, said inner housing member defining with said housing an 3,924,963 13 14 annular discharge flow channel, and said stationary Y of runners are arranged and Connected Senes to form a unitary runner, said unitary runner capable of guide means for impeller flow being disposed in said being axially removed from the housing.

channel for minimizing tangential velocity components in said flow.

16. The turbomachine of claim 4 wherein said plural- UNITED STATES PATENT OFFICE EETTMCATE OF CORRECTION PATENT NO. 3, 924,963 6 DATED December 9, 1975 |NVENTOR(S) Dieter G. Zerrer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2 line 49, change "impossiblity" to impossibility;

Q line 58, change "statinary" to --stationary.

Column 4, line 68, change "turbomachine" to -turbomachines-. 0

Column 5, line 20, change "turbomachine" to --turbomachines-;

m line 32, change "yield" to -field--.

a Column 7,

lines

58, 59, 60, 61, 63 and 66, change "intergal" to -integral-;

Column 14, line 3, change "the" to -said.

' Signed and Scaled tlus eighth Day Of June 1976 aseut fittest.

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner of Parents and Trademark:

Claims

9. The turbomachine of claim 7 including a forward shroud member, said forward shroud member mounting both said inducer vanes and said inlet inner casing on said shaft.

10. The turbomachine of claim 1 including a rearward shroud member, said rearward shroud member mounting said impeller vanes on said shaft.

15. The turbomachine of claim 1 including an inner housing membEr arranged in downstream position adjacent said centrifugal impeller portion, means mounting said inner housing member within said housing, said inner housing member defining with said housing an annular discharge flow channel, and said stationary guide means for impeller flow being disposed in said channel for minimizing tangential velocity components in said flow.

16. The turbomachine of claim 4 wherein said plurality of runners are arranged and connected in series to form a unitary runner, said unitary runner capable of being axially removed from the housing.