US3771900A

US3771900A - Graduated screw pump

Info

Publication number: US3771900A
Application number: US00189424A
Authority: US
Inventors: S Baehr
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-10-14
Filing date: 1971-10-14
Publication date: 1973-11-13
Anticipated expiration: 1990-11-13

Abstract

An improved pump of the rotary or centrifugal type utilizing paired, opposed, spiral ramps mounted on a rotating conical impeller within a frusto-conical housing, the ramps starting and ending approximately 180* opposed from one another and running in the same direction on the impeller hub outer surface substantially 360* each.

Description

United States Pa /tent [191 Baehr Nov. 13, 1973 GRADUATED SCREW PUMP [76] Inventor: Samuel J. Baehr, LaPrairie, 111.

[22] Filed: Oct. 14, 1971.

21 Appl. No.: 189,424

[52] US. Cl 415/72, 415/215", 416/176 [51] Int. Cl. F04d 3/02, F04d 29/52 [58] Field of Search 415/74, 215, 71, 415/72; 416/176, 177; 29/156.8; 259/9, 10

[56] References Cited UNITED STATES PATENTS 779,473 l/1905 Freid .Q 415/72 793,717 7/1905 Dixon 416/176 1,797,455 3/1931 Vose 415/215 2,233,825 3/1941 Walsh et a1. 415/215 8/1971 Ronel1enfitch...l 415/72 FOREIGN PATENTS OR APPLICATIONS 126,899 10/1878 France ..4l5/72 961,272 11/1949 France ..415/72 Primary Examinerl-1enry F. Raduazo Attorney-Thomas M. Scofield [57] ABSTRACT An improved pump of the jrotary or centrifugal type utilizing paired, opposed, spiral ramps mounted on a rotating conical impeller within a frusto-conical housing, the ramps starting and ending approximately 180 opposed from one another and running in the same direction on the impeller hub outer surface substantially 360 each.

7 Claims, 7 Drawing Figures PAIENIEUuuvmszs 3.771.900 SHEEI 10F 2 INVENTOR ATTORNEYS GRADUATED SCREW PUMP CENTRIFUGAL DEVICES Mechanical devices for moving air or other gases and operating on the centrifugal principle may be classified 1. FANS (high rates of delivery at low pressure);

2. blowers (high rates of delivery at medium pressure); and

3. compressors (high pressure delivery).

The operating principle is the same for all three classes of centrifugal machines. The air is drawn in at the center of the casing by a rotating impeller which contains a number of passages arranged in a spiral pattern. On flowing through these passages, the air is given an acceleration and emerges under pressure from the spiral casing (volute) of the fan.

CENTRIFUGAL PUMPS Pumps are used for the transport of liquids or gases through pipes. The general principle is as follows: In one portion of the pump, a suction is produced to draw liquid in, in a second portion of the'pump, an excess pressure overcoming the counter-pressure is created, forcing the .fluid (liquid or gas) away.

Several types of pumps may be distinguished on the basis of their principle of operation:

1. piston pumps operating eitehr with reciprocating pistons or rotating same;

2. centrifugal pumps operating with rotating blades; and

3. jet pumps utilizing the energy of flowing fluids. The instant device is an improvement in centrifugal pumps.

In a centrifugal pump an impeller fitted with vanes imparts motions to the water or other fluid. A centrifugal pump gives asteady flow as compared to a piston pump which typically delivers water in a pulsating stream.

The pressure for achieving the required delivery head" is produced by centrifugal acceleration of the fluid by the vanes in the rotating or on the rotating impeller. The fluid flows axially toward the face of the impeller, is deflected by it and is driven and flows outwardly' through the apertures between the vanes. In this manner, the fluid undergoes'a change .in direction and is accelerated. The action of the impeller blades upon the fluid thus produces an increase in pressure at the pump outlet.

In some centrifugal pumps. on leaving the zones of the impeller blades, the fluid may first. pass through a ring of fixed vanes surrounding the impeller called a diffuser. In the latter, having gradually widening passages, the velocity of the liquid is reduced and itskinetic energy is converted into pressure energy. Such conversion is completed in the volute of the pump, that is, the gradually widening spiral casing. (The instant device does not employ a diffuser.)

In some centrifugal pumps, a diffuser is not employed, with the fluid being pumped passing directly from the zone of the impeller blades to the volute of the pump housing. Such is the case in the instant device.

Simple centrifugal pumps of the type described, having but one level or zone of impeller blade cannot, however, produce high delivery heads. In a conventional centrifugal pump, a higher delivery head can be obtained by mans of the stacking of centrifugal pump stages in which two or more impellers are mounted one behind the other. In' conventional centrifugal pump construction such increase in complexity greatly increases cost of materials and manufacture. The instant device achieves the same result without the structural complexity and cost of a conventional centrifugal pump of multiple stages. I

As a rule, cintrifugal pumps are not self-priming. That is, they are unable to draw in fluid on first being started up. This is because, when the impeller is revolving in air in the empty casing, it cannot devleop sufficient suction. Such pump, in liquid work, therefore has to be primed (filled with the liquid to be pumped) for starting.

DESCRIPTION OF THE INVENTION In the instant device, with paired inclined ramps or vanes mounted upon a conical impeller, the impeller rotates with the fluid entering the housing axially of the conical inclination of the housing and impeller outer surface. The smaller diameter open ends of the paired inclined ramps pick up the fluid in their rotation and thrust it axially of and outwardly in the housing, guided by the under surfaces of the vanes, the outer surface of the impeller and the inner surface of the housing. The fluid thus moves both axially of the housing and outwardly thereof under the impetus of the pumping impeller which is one subject of the instant invention.

The function of each of the inclined ramps mounted on the impeller of this pump is to produce thrust to move fluid through the pump by giving momentum thereto. The fluid or liquid is displaced both axially of the housing and outwardly thereof by each of two helical ramps on the conical impeller.

Each of the ramps illustrated in the drawings describes a circumferential helical curve around the impeller from the smaller diameter end thereof to the larger diameter base thereof. The ramps shown here are 360 curves, that is, they pass around the axis of the impeller cone'one time each. The pitch of each helical ramp varies with respect to' the axis of rotation of the impeller as they circle the impeller outer surface. This pitch varies in the instant device from a greater pitch at the lesser diameter end of the impeller body to a lesser pitch at the greater diameter end of the impeller body.

- vapor are formed (cavitation). The instant pump construction is such as to permit higher rotational velocities, greater throughput and higher delivery head without cavitation or the onset thereof.

The function of the inclined helical ramps is to convert the torque developed by the power source and imparted to the drive shaft into a propulsive thrust to drive fluid through the pump. This thrust is produced by acceleration axially and radially of the pump housing and impeller therein.

PRiOR ART This apparatus improves over the constructions and devices seen in the following prior art patents.

Schetzel, U.S. Pat. No. 482,655, issued Sept. 13, 1892. I

Hutchinson, U.S. Pat. No. 566,179, issued Aug. 18.

DESCRIPTION OF THE DRAWINGS In the drawings, which form a part of the instant specification and are to be read in conjunction therewith, embodiments of the invention are shown and, in the various views, like numerals are employed to indicate like parts.

FIG. l is a side, partly cut away view of an improved rotary pump of the centrifugal screw type, the inlet end of the pump housing being to the right in the view and the output end thereof to the left in the view.

FIG. 2 is a view taken along the line 2-2 of FIG. 1 in the direction of the arrows, but with the frustoconical pump housing removed so that the configuration of the spiral or helical paired ramps or screws can be clearly seen.

FIG. 3 is a view taken along the line 3-3 of FIG. 1 in the direction of the arrows, showing the internal configuration of the volute discharge chamber.

. FIG. 4 is a view taken along the line 4-4 of FIG. 3 in the direction of the arrows.

FIG. 5 is an end view of the discharge end of the pump in FIG. 1 looking from left to right in the view of FIG. 1.

FIG. 6 is an end view of the device of FIGS. 1-5, inelusive, comprising a view of the right-hand end of FIG. 1 looking to the left in the view, this view being opposite to that view seen in FIG. 5.

FIG. 7 is a view similar to that of FIG. 1, but omitting the particular intake housing or casing seen in the right hand side of that Figure whereby to provide a universal input flange mounting to connect with any sort of pipe, duct or conduit.

OBJECTS OF THE INSTANT INVENTION One object of the instant invention is to provide an improved pump of the rotary or centrifugal type.

Another object of the invention is to provide an improved, rotating pump of the centrifugal type wherein increased delivery head is provided by utilization of paired, opposed, spiral ramps mounted on a rotating conical impeller within a frusto-conical housing.

Another object of the invention is to provide an improved rotary pump of the centrifugal type wherein paired, spiral ramps are provided, of such structure and configuration as to minimize cavitation, increase delivery head at a given rate of rotation and further minimize or prevent wobble, vibration or eccentric thrust in operation of the pump at any design speed.

Another object of the invention is to provide an improved rotary centrifugal pump wherein a higher delivery head is obtained without the necessity of stacking centrifugal pump stages mounting two or more impellers behind one another.

Another object of the-invention is to achieve major improvements in operation, output and delivery head of rotary centrifugal pumps without any increase in structural complexity or cost thereof.

Another object of the invention is to provide an improved rotary pump of the centrifugal type incorporating improved features providing long and dependable service, which features contribute to reduced operating and maintenance costs, minimize vibration and provide an extended normal period of maximum efficiency.

Another object of the invention is to provide an improved rotary centrifugal pump wherein the pump vanes or blades act as scavengers for material that might normally lodge between the impeller and pump casing, whereby the pump is able to handle liquids containing unusual maounts of grit, ash or abrasive materials.

Another object of the invention is to provide an improved rotary centrifugal pump effectively useful for all normal drainage service, including buidling, industrial and municipal applications, wherein the impeller is fully enclosed and of a non-clogging type assuring maximum flow with minimum power useage.

Anotehr object of the invention is to provide a device as described performing as an improved rotary centrifugal pump under rugged pumping conditions, which combines high performance with structural simplicity and further provides for easy installation and maintainance, wherein the rotating parts operrte quietly and smoothly and the provision of heavy-duty operating parts assure a long, trouble-free life.

Another object of the invention is to provide a pump construction wherein the design and construction of the thrust or guide bearing housing(s) on the drive shaft readily permits axial adjustment of the shaft and impeller assembly within the housing of the pump. This feature makes possible a close and accurate running clearance, preventing leakage losses from the impeller back to suction. Such close clearance also guards against solid particles becoming wedged between the impeller and the housing.

Another object of the invention is to provide an improved rotary centrifugal pump having two driving means 180 opposed, providing a wider, uniform width feed channel therethrough and therebetween, with a change (decrease) in pitch of the drivers as the volume being dealt with increases, whereby to maintain rate efficiency in the action of the pumping impeller throughout its entire stroke on the fluids being pumped. Stated otherwise, the improved impeller driving means in the subject pump utilizes a graduated screw action with decreasing pitch as the diameter of the working screw on the impeller hub increases.

Another object of the invention is to provide a novel roatry centrifugal pump wherien improvements are provided over the known prior art, in all stages or portions of the operating pump, namely, in pickup of the ,fluids or liquids being pumped, secondlywithin the housing of the pump in the zone where the driving impeller imparts force and impetus to the fluids and, fi-

nally, in the discharge thereof from the pump, including the volute chamber housing, whereby, as mentioned, all stages and oeprations of the pump are improved over the known art.

Another object of the invention is to provide an improved pump of the rotary or centrifugal type which, in many features of performance and results, obsoletes the available prior art centrifugal pumps; Specifically, in pumps of the open flow type, all features conventionally used in valuing such pumps are improvecl'such as the horsepower required for given head pressures (less), the gall9ons per minute pumped (for a given outlet orifice size), and the like.

Another object of the invention is to provide an improved rotary or centrifugal type pump with improved performance for all conventional purposes for which such type pumps are used, the effective working range of the pump starting at a lower rpm and ending at a higher rpm than conventional centrifugal and rotary pumps.

Other and further objects of the invention will appear in the course of the following description thereof.

FIGS. 1-5, INCLUSIVE Looking first at FIGS. 1-5, inclusive, therein is shown an improved rotary or centrifugal pump. At 10 there is generally designated a frusto-conical housing, casing or chamber which has a lesser internal diameter input end 10a and a greater internal diameter outlet or output end 1012. In the construction of FIGS. 1-5, inclusive, attached to and extending axially in line with the lesser diameter 10a is an elongate cylindrical casing or housing 11. Circumferentially connected to the greater internal diameter end 10b is a continuous flange 12.

A circular, continous flange 13 is connected to cylindrical housing 11 to which is removably connected a mating and matching flange 14. This connection is accomplished by bolts 15 and nuts 15a. A bearing of conventional sort 16 carries for rotation one end of drive shaft 17, this bearing being mounted on and carried by flange 14. End closure 18 is also carried by flange 14 and closes and seals off the other end of housing 11 from frusto-conical housing 10.

A further cylindrical inlet housing 19 connects to housing 11 via opening 20 and has removable access plug 21 in the end thereaway fromhousing 1 l with conventional hex head or nut 22 fixedly attached to the outer surface thereof. A threaded (internally) fitting or arm 23 is connected at right angles to inlet pipe or housing 19 and may recieve in removable threaded engagement pipes or ducts for input of liquids, water, fluids, mixtures of liquids, powdered solids and the like as at 24.

Attention is drawn to the fact that all of the structure encompassed in the above description including the number 11-24, inclusive (save for numeral 12), is essentially optional structure merely illustrating one useful, but not limiting, input construction for the centrifugal pump to be described. Yet additionally, this de-' scribed variation, particularly seen in FIGS. 1 and 2, illustrates a for or modification of the pump construction utilizing bearings on'drive shaft 17 at both ends of the impeller and pumping screws or ramps. This construction is not necessary, but may be optimum or preferred in certain pumping conditions and to meet certain especially-rigorous circumstances. The modification of FIG. 6 shows a universal attachment form of the centrifugal pump omitting the said described inlet and double bearing structure.

Referring now to the contents or operating elements within the frusto-conical housing 10, mounted on drive shaft 17, which extends through and out of chamber 10, both ends thereof, in the modification being described, is a frusto-conical or near conical impeller hub 25. The larger diameter end 25a of impeller hub 25 extends past the larger diameter end 10b of housing or casing 10, as well as past flange 12. On the other hand, the lesser diameter end 25b of hub 25 stops well short of the lesser internal diameter end 10a of housing 10. The slope of the outer surface of impeller hub 25 is substantially concentric with the slope or angle of the walls of the housing 10 so that the annulus 26 defined between the outer surface of impeller hub 25 and the inner surface of housing 10 is of substantially uniform volume moving from the input end of housing 10 to the output end thereof.

A pair of spiral ramps or blades generally designated 27 and 28, respectively, are provided within said housing or chamber 10, each mounted fixedly on the outer face of conical impeller hub 25 and extending in a helical curve around and along the said outer surface of the impeller hub 25. Each

ramp

27 and 28 extends substantially 360 (that is, each makes a complete circle) around the said impeller hub 25 (and also around the axis of drive shaft 17). Thus it may be seen that the respective smaller outer diameter (with respect to drive shaft 17) ends 27a and 28a are 180 opposed to one another, as are the greater outer diameter ends 27b and 28b thereof. It should be emphasized that the terms lesser and greater outer diameter ends of the ramp do not refer to the width of the ramp itself, which remains essentially constant, save for minor variations to be described due to pitch change, in the essentially uniform volume annulus 26. Alternatively stated, and perhaps more accurately, the ends of the

ramps

27 and 28 which are positioned at the lesser inner diameter portion 10a of the housing 10 are 180 opposed to one another as at 27a and 28a, while the ends of the said ramps 27 and 28 which terminate same at or past the greater internal diameter end 10b of housing 10 are likewise 180 opposed to one another as at 27b and Ramps or

blades

27 and 28, starting and ending approximately l80 opposed to one another, run in the same direction on the impeller 25 outer surface. The ends 27a and 28a of

ramps

27 and 28 are so pitched as to substantially align with the least diameter portion 10a of housing 10. Thereafter, as the ramps run from the input or inlet end of chamber 10 to the output or outlet end thereof, the pitch of the said ramps changes, finally to reverse to a slight degree at the ends 27b and 28b thereof in a manner to be described. Specifically,

the angle between the axis of the drive shaft 17 and,

' say, the end 28a of ramp 18, as indicated at A in FIG.

1, is less than This angle gradually approaches 90 or perpendicular to the axis of shaft 17, thereafter to, be greater than 90 at the end 27b. The same is true of ramp 27 at its ends 27a and 27b and the changing pitch thereof in its rotation around the impeller hub 25. By varying the pitch of the ramps or

blades

27 and 28 in the manner described, the volume enclosed between the flights thereof is enabled to be maintained essentially constant. Thus, the tendency of the pump to-cavitate or lose thrust, particularly at increased rates of throughput and increased rpm of the drive shaft and impeller hub 25 is markedly decreased, if not done away with.'The pairing of the ramps or

blades

27 and 28 and the matching of their extensions on and with respect to the impeller hub 25 with 180 opposed ends, as described, operates to balance the device at high rates or rotation (indeed, all rates of rotation) and lessen and prevent oscillation, wobble, eccentric thrust and vibration of the pump in operation.

Referring to the left-hand side or portion of FIG. 1, therein is shown and generally designated at 29 a volute output or outlet chamber of a particular configuration. Such is perhaps best seen in FIGS. 35, inclusive. Centrally positioned of said outlet chamber 29 is a cylindrical hub 30 having a passage 31 therethrough to receive and pass in rotation drive shaft 17 Hub 30 is positioned adjacent the larger end 25a of conical impeller hub 25 and the outer diameter thereof is preferably equal to the outer diameter of portion 250 of hub 25. Spaced circumferentially outwardly from the outer face or wall 300 of hub 30 is a circular wall 32 which, together with wall or face 30a, defines therebetween the volute outlet chamber. A continuous floor 33 communicates and connects between

walls

30a and 32 as at 33, increasing substantially continuously in depth from a least depth inlet end 33a thereof towards and into outlet end 33b 360 therefrom of greater depth. The transition between the inlet and the outlet ends 33a and 33b of floor or wall 33 defines, at 34, the outlet orifice or opening of the volute chamber 29. Any suitable outlet duct or pipe 35 may be taken off therefrom. Flange 36, having suitable bolt openings 37 therethrough, is adapted to face, match and be engaged with flange 12 on chamber by conventional means such as bolts and nuts, screws or the like. Preferably, suitable conventional gasketings such as 37 may be provided therebetween. Exteriorly of volute outlet chamber 29 (and optionally integral therewith or removable therefrom) is provided conventional bearing 38 to receive drive shaft 17.

Reference to FIG. 4 will show how the upper boundary 33a of floor 33 over opening 34 is tapered downwardly, radially outwardly, to match the reverse pitch of the greater diameter ends of the ramps. The end 28b of ramp 28 is shown passing immediately over the floor portion 33a in the view of FIG. 4, thus illustrating how there will be a final push by the following blade or ramp to that water carried between same and the preceding ramp as the water goes out the opening 34. As floor 33 moves away from zone 33a, it levels off as is seen at 33b. Optionally, floor 33a may be parallel with floor 33b and the pitch of the ramp ends 28b and 27b at right angles to the drive shaft 17. However, this does not give the optimum wiping or thrusting action into the opening 34.

OPERATION As previously noted, as a rule, centrifugal pumps are not self-priming. This is the case in the instant device, all forms. Therefore, in liquid work, the instant pump must be primed (filled with the liquid to be pumped) for starting. Therefore, it is assumed that pipe 24, fitting 23, housing 19, housing 11 and casing or housing 10, as well as the volute chamber outlet of the pump are filled with the liquid, such as water, and in continuous communication via pipe or duct 24 with the body of liquid or water to be pumped. Any suitable prime mover, such as a gasoline motor, electric motor, or the like, is coupled with shaft 17 by suitable conventional means such as belt or pulley, gears or the like and rotation of shaft 17, the impeller hub 25 and theramps 27 and 28 thereon is begun in a direction as seen in the arrows designated 40 in FIG. 1 and 41 in FIG. 2. Thus, the direction of rotation in the view of FIG. 2 is counterclockwise.

Rotation of shaft 17 and the elements connected therewith described operates to draw liquid from housing 11 into housing 10 and discharge same from the volute chamber 33 through pipe 35. Water or other liquid is thus forced both axially of shaft 17 and radially outwardly by the pitch of the

ramps

27a and 28a which initially engage an input quantity of water to the inlet end 10a of chamber or housing 10. As the water is driven in the annulus 26 from right to left in the view of FIG. 1, it is accelerated or urged both radially outwardly from the axis of shaft 17 and longitudinally of the axis thereof. The ends 27b and 28b are so configured as to align with the floor 33 at the junction or transition point 34- whereby to achieve the most efficient impetus of the liquid or fluid being impelled by the

ramps

27 and 28 into the output opening 34 and pipe 35.

By using a graduated screw pump as disclosed herein, the inflow of water or material to the action zone of the pump (housing 10) is least restricted. The pitch angle of the

ramps

27 and 28 is preferably approximately 45 on the intake or small end of the pump impeller 25 at 27a and 28a. As the graduated screw progresses toward the discharge end of the ramps, or, rather, as the water or liquid being pumped moves along the ramps toward the discharge ends 27b and 28b thereof, the pitch of the ramps reverses with respect to the axis of rotation, whereby to result in ends 27b and 28b at an angle of some 15 or slightly less with respect to the axis of drive shaft 17. This pitch change and reversal over the length of each of the spiral ramps results in the optimal or best wedging action or driving force. The described and shown structure provides, as noted, the least restriction on fluid pickup at the intake end of the ramps and the greatest possible compressibility and driving force at the discharge ends thereof.

Three stages in the development of rotary centrifual pumps might be distinguished as including: (l) the straight bladse centrifugal pump, (2) the curved blade centrifugal pump with an improved centrifugal action and, (3) the greatly improved graduated screw principle herein presented. With resptct to (2), the curving of the blades and the additional wedge action provided a better design. With respect to the latter, not only is the driving length and wedge action increased, but also the driving force is changed from radial to a combination of radial and longitudinal.

In the improved pump, the graduated screw ramps are built around a cone whereby to block out the low pressure area. This merely eliminates feedback.

DESCRIPTION OF MODIFICATION OF FIG. 7

The construction of the modification or variation of FIG. 7 is substantially the same as that of FIGS. 1-5, inclusive, save for such specific differences and changes as will now be immediately described. Therefore, all parts of the device of FIG. 7 which are exactly or substantially the same as those of FIGS. l-S, inclusive, are numbered the same, but primed. These parts, their interrelationship, structure and function will not be redescribed and the previous description of the like numbered parts (unprimed) are incorporated herein by reference.

The distinctions of the device in FIG. 7 over the device of FIGS. 1-5, inclusive, lie in the following:

1. The shaft 17' upon which the conical impeller hub 25 is mounted is a stub shaft, that is, it extends in one direction only from its connection with the impeller hub 25 for connection, coupling or engagement with its prime mover in rotation or a conventional power source. Thus, the right-hand extension of shaft 17 in FIG. 1 and the right-hand side bearing 16 are omitted. This omission permits the impeller hub 25 to more closely approach a more conical shape at its lesser diameter end 25b.

2. All of the housings ll, 19 and fitting 23 are omitted whereby to permit direct engagement and attachment of the input end a of the housing 10' to any suitable pipe, duct or conduit or fluid source of conventional type by means of the circumferential attachment flange 42 by screws, bolts, or the like. This pump or pumping device may, alternatively, be attached to the side wall of a tank or reservoir and the flange 41 surrounding an opening therein or the like.

3. The bearing 38', attached like bearing 38 to the hub 30' (30), although of conventional type, is preferably different in its character and relationship to shaft 17' than bearing 38 with respect to bearing 17. That is, the bearing area is preferably of greater extent to better control and contain oscillation or wobble of the shaft in its rotation, fix the shaft longitudinally of the housing 10' and the like.

The relative position of the

ramps

27 and 28 or 27 and 28 with respect to the inner wall 10 M10 of the housing may be adjusted by longitudinal or axial adjustment of

shaft

17 or 17, but same is preferably adjusted by variation in the size and configuration of the impeller cone 25 or 25' so that same always rotates in essential liquid sealing fashion with respect to hub 30 or 30'.

4. In FIG. 7 the bearing housing 48' contains a plurality of bearing

races

43 and 44 within which'travel ball bearings 43a and 44a of conventional type in conventional manner. Snap rings 45 and 46 retain bearing race 43 within housing 38 and shims 47 and 48 are provided so that the race 43 may be moved longitudinally within the housing 38. The same is true of the race 44 although the shims and snap rings are notnumbered with respect to this race.

From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and notin a limiting sense.

l claim: I 1

1. In a pump,

a casing having a volute outlet chamber and a frustoconical housing connected thereto,

the large end of said frusto-conical housing opening into said volute outlet chamber,

an impeller mounted to rotate within said frustoconical housing,

said impeller of substantially conical shape and concentrically mounted within said frusto-conical housing,

whereby to provide a circumferential, substantially uniform width annular chamber between the outside surface of said frusto-conical impeller andthe interior surface of said frusto-conical housing, a pair of spiral ramps each mounted in a helical curve around and along the outer surface of the impeller,

each said spiral ramp extending substantially 360 (making a complete circle) around said impeller and the axis of rotation thereof, said ramps starting and ending approximately 180 opposed from one another and running in the same direction on said impeller outer surface, and

drive means for rotating said impeller and the ramps mounted thereon in rotation within said housing whereby to propel fluid input at the lesser diameter end of the housing and impeller therethrough, into and out of said volute outlet chamber.

2. A device as in claim 1 wherein said volute outlet chamber increases substantially continuously in depth from an inlet end thereof towards and into an outlet end thereof substantially 360 therefrom, the transition between the inlet and the outlet ends defining the outlet orifice,

the said volute chamber positioned around and outside of a central hub of outer diameter substantially equal to the larger diameter of the frusto-conical impeller, which rotates thereon as a base,

the lesser diameter apex of the impeller body stopping short of the lesser diameter end of the housing, with the lesser diameter ends of the ramps extending to and aligning substantially with the lesser diameter end of the frusto-conical pump housing, and

the base of the impeller extending past the largest diameter end of the frusto-conical housing together with the larger diameter ends of said ramps.

3. A device as in claim 2 wherein there is a limited zone of cylindrical form adjacent to the volute chamber and opposing the larger diameter end of the impeller into which the inclined ramps penetrate.

4. A device as in claim 1 wherein the pitch of said ramps decreases substantially continuously from the inlet end of the frusto-conical housing towards the outlet end of said housing.

5. A device as in claim 1 wherein the helical ramps, at the inlet end of the frusto-conical housing are positioned at an angle of less than to the axis of rotation of the impeller away from the direction of flow into the housing and the greater diameter ends of the ramps extend at substantial right angles to the drive shaft immediately before the volute outlet chamber.

6. A device as in claim 4 wherein the pitch of each said ramp reverses from one end thereof to the other.

7. A device as in claim 5 wherein the pitch of each said ramp reverses from one end thereof to the other. l

Claims

1. In a pump, a casing having a volute outlet chamber and a frusto-conical housing connected thereto, the large end of said frusto-conical housing opening into said volute outlet chamber, an impeller mounted to rotate within said frusto-conical housing, said impeller of substantially conical shape and concentrically mounted within said frusto-conical housing, whereby to provide a circumferential, substantially uniform width annular chamber between the outside surface of said frusto-conical impeller and the interior surface of said frusto-conical housing, a pair of spiral ramps each mounted in a helical curve around and along the outer surface of the impeller, each said Spiral ramp extending substantially 360* (making a complete circle) around said impeller and the axis of rotation thereof, said ramps starting and ending approximately 180* opposed from one another and running in the same direction on said impeller outer surface, and drive means for rotating said impeller and the ramps mounted thereon in rotation within said housing whereby to propel fluid input at the lesser diameter end of the housing and impeller therethrough, into and out of said volute outlet chamber.

2. A device as in claim 1 wherein said volute outlet chamber increases substantially continuously in depth from an inlet end thereof towards and into an outlet end thereof substantially 360* therefrom, the transition between the inlet and the outlet ends defining the outlet orifice, the said volute chamber positioned around and outside of a central hub of outer diameter substantially equal to the larger diameter of the frusto-conical impeller, which rotates thereon as a base, the lesser diameter apex of the impeller body stopping short of the lesser diameter end of the housing, with the lesser diameter ends of the ramps extending to and aligning substantially with the lesser diameter end of the frusto-conical pump housing, and the base of the impeller extending past the largest diameter end of the frusto-conical housing together with the larger diameter ends of said ramps.

5. A device as in claim 1 wherein the helical ramps, at the inlet end of the frusto-conical housing are positioned at an angle of less than 90* to the axis of rotation of the impeller away from the direction of flow into the housing and the greater diameter ends of the ramps extend at substantial right angles to the drive shaft immediately before the volute outlet chamber.

7. A device as in claim 5 wherein the pitch of each said ramp reverses from one end thereof to the other.