Claims:
Having thus described the present invention, what is claimed is
1. A rotary pump with displacement and centrifugal action comprising in combination a cylindrical casing, a shaft, two stationary disks mounted on said shaft coaxially therewith and secured to said casing, each of said disks having a shaped inner surface opposite to one another, a substantially cylindrical rotor disk secured to said shaft between said stationary disks and coaxially therewith and having a plurality of equidistanced radial slots, a plurality of quadrangular vanes received in said slots and adapted to oscillate therein around a point on the axis of said shaft, a suction duct in said shaft, the surfaces of said disks being shaped to form a cyclical sinusoidal surface, means providing suction ports immediately downstream of the crest of the sinusoidal surface near the disk axis, means providing delivery ports immediately upstream of said crest on the periphery of said shaped disks, means providing a plurality of apertures in said shaft duct and communicating with said suction ports in said shaped disks, a peripheral scroll duct extending around said casing and communicating with said delivery ports of said shaped disks and a peripheral delivery duct communicating with said scroll duct.
2. A pump as claimed in claim 1, wherein said vanes have two lateral parallel sides continuously sealing on said inner shaped surfaces and two transverse sides having the shape of an arc of circle with its center on the axis of said shaft.
3. A pump as claimed in claim 1, wherein the inner surfaces of said shaped disks are generated by a line having its one end on the shaft axis and its other end rotary around said axis and simultaneously describing a cyclic curve, said cyclic curve consisting of at least one sinusoid so as to obtain at least one concave surface and at least one convex surface.
Description:
The present invention relates to a rotary pump with oscillating vanes.
As it is known to the persons skilled in the art, the most different problems concerning the lifting and pressurizing of liquids are solved by means of pumps, of which a large variety exists.
The choice of the type of pump is determined by numerous factors; displacement pumps are used when rather relevant values of head are concerned, while the centrifugal pumps are used when the delivery flow is required with high rates or with a great regularity.
The purpose of this invention is that of embodying a pump which, at parity of occupied space and of available power, offers simultaneously, and by simple means, the advantages of both the displacement pumps and of the centrifugal pumps.
According to this invention a rotary pump is provided comprising in combination a casing having a substantially cylindrical shape, a pair of shaped discs, co-axial with the casing and rigid therewith, a separating space between said two discs, ideally obtained by a quadrangular surface which rotates about said casing axis and simultaneously describes by every one of its points, a cyclic curve, a rotor co-axial with the casing, operated by a prime mover through a transmission shaft and tangent to the top lines of said shaped discs, one set of vanes corresponding to said quadrangular surface and received within slots provided axially in said rotor, suction ports located immediately downstream of each top line of said shaped discs, and communicating with the internal cavity of the rotor shaft, delivery notches machined peripherally immediately upstream of each top line of said shaped discs, and in correspondence with ports machined on the casing and communicating with the conveying scroll.
The rotor carries a set of diametrical grooves destined to allow the vanes to oscillate according to the form of the shaped internal surfaces of said discs.
The two radial sides of the vanes are such, as to effect constantly the seal on the two surfaces of said discs, while the axial sides of the vanes have the innermost the shape of an arc of circle and the outermost the shave of a sphere, with its centre on the rotor shaft.
Also according to this invention, the peripheral surface of the space separating the two shaped discs is spherical.
This invention will be now described with reference to the attached drawings showing by way of non limitative example one preferred embodiment of the invention itself.
IN THE DRAWINGS:
FIG. 1 shows an exploded view of the fundamental elements of the pump;
FIGS. 2 and 3 show two cross sectional views of the pump, perpendicular to the axis of rotation;
FIG. 4 shows the mounting detail of one of the vanes;
FIG. 5 is the cross section V--V of FIG. 2;
FIG. 6 is the cross section VI--VI of FIG. 3, with a pair of vanes located in the position shown in dashed line in FIG. 3;
FIG. 7 is the cross section VII--VII of FIG. 3;
FIGS. 8, 9 and 10 show one of the shaped discs in some turned over cross sections, taken along the planes VIII--VIII, IX--IX and X--X of FIG. 2;
FIGS. 11, 12 and 13 show three characteristic positions of one of the vanes;
FIG. 14 shows diagrammatically the operative stroke related to FIG. 2, developed on one plane;
FIG. 15 shows the detail of the three elements of FIG. 1 in their operative position.
With reference to FIG. 1, the numeral references 1 and 2 denote the two discs co-axially mounted. The external faces of the two discs 1 and 2 are flat, while the internal faces 3 and 4 consist of two identical and superposable surfaces having as directrix a cylindrical sinusoid or other cyclic curve and as generatrix a curve or a straight line r (FIG. 1) having a fixed starting point on the very axis of the cylinder. For simplicity of representation and of construction, said cyclic curve is formed, in the drawings, by a very flattened sinusoid which describes two entire periods through the 360° revolution, whereby each of the surfaces 3 and 4 shows two "top lines" (or maximum convexity lines) L, and two "depression lines" (or maximum concavity lines) D.
Between the two shaped discs 1 and 2 the rotor 5 is interposed, and the lateral symmetrical faces of said rotor disc 5, delimited, in the described example, by conical surfaces, are tangent to the top lines L of said two discs. In the rotor 5 slots angularly equispaced are provided, and in said slots are inserted an equal number of vanes (four in the exemplicative drawing) 6, 7, 8 and 9 (see also FIGS. 2, 3 and 4) which are capable of oscillating in the radial plane defined by said slots. The outer edge of the vanes is delimited by a spherical surface having a radius r with its centre on the axis O, and the same spherical surface delimits peripherally the two shaped discs 1 and 2 and the rotor 5 (see FIG. 15).
As it is shown in FIGS. 11, 12 and 13, the distance A separating the two surfaces 3 and 4 is always constant, whereby each vane, for instance the vane 6, having the same width A, obtains constantly the seal by its lateral edges on the aforesaid surfaces.
In FIG. 11, the vane 6 has its left-hand lateral edge coincident with one of the top lines of the surface 3, while the other lateral edge is located on a depression line of the surface 4. The axis of symmetry B of the vane will be deflected with respect to the straight line E perpendicular to the axis O through an angle α which corresponds to one half of the angle 2α between the top line and the depression line. When the vane 6 together with the rotor has rotated through 45° (FIG. 12) the straight lines B and E are coincident, and after a further rotation through 45° the left hand lateral edge is coincident with one of the two depression lines of the surface 3, while the other edge will be located on one top line of the surface 4.
In order to allow for the vanes the above described oscillations, the vanes have their lower edge, or internal edge, delimited by a cylindrical surface having the radius r1 and its axis perpendicular to the axis of rotation O (FIG. 13). Said edge is inserted into a meridian groove 10 (FIG. 4) of the hub 11 of rotor 5 mounted on the shaft 12 by means of a key 13 of other suitable system.
The shaft 12 (see also FIGS. 5, 6 and 7) is journalled by means of bearings on two parallel plates 14, provided with mounting lugs 15 and spaced apart by the casing 16, which is made in two parts, and fixed to said plates by the bolts 17. The two shaped discs 1 and 2, in turn, are rendered rigid with the casing by means of the security dowels 18. The internal surface of the casing 16 is spherical so that the upper edge of the vanes will make constantly the seal thereon. About the casing 16 is located a scroll 19 leading to the delivery duct 20 (FIGS. 2 and 3).
The shaft 12 (FIGS. 5, 6, 7) is connected to whatsoever prime mover, not shown in the FIGURE which operates the rotor 5. One part of the shaft 12, which serves also the function of the suction duct, is provided with an internal cavity 21 which through the apertures 22 communicates with the suction ports 23 and 24 provided in the shaped disc 1 and angularly spaced through 180°. The apertures 22 are in number of four connected by an annular chamber 22a allowing a permanent communication between the duct 21 and the suction ports 23 and 24.
Likewise there are four apertures 25 (FIG. 7) communicating with the suction ports 26 and 26a provided in the shaped disc 2, through the annular chamber 25a.
At the periphery of the shaped disc 1 are provided two notches 27 and 28, angularly spaced through 180°, which communicate with the delivery ports 29 and 30 provided through the casing 16 and leading to the scroll 19.
Likewise, the disc 2 is provided with two notches 31 and 32 communicating with the delivery ports 33 and 34 leading to the scroll 19. As it is shown in the FIGS. 1 and 2, the delivery notches 27 and 28 of the shaped disc 1 end in correspondence with the top lines L, while the suction ports 23 and 24 begin a short distance after the top lines L and end at an angular distance of 45° starting from said lines.
The operation is as follows (see FIGS. 2, 3 and 14): let assume that the rotor 5 rotates clockwise as shown in FIG. 2, wherein the dotted zones show the suction strokes, while the dashed zones show the delivery strokes. The vane 6 takes the liquid through the suction port 23 in the space delimited by the vane 6, by the shaped disc 1, by the casing ring 16 and by the rotor 5 making the seal in correspondence with the top line L. There is also a liquid suction downstream of the vane 7. Simultaneously there is also a suction downstream of the vanes 8 and 9. The suction is due to the fact that the volumes of the spaces downstream of the vanes 6, 7, 8 and 9 increase as shown in FIG. 14.
The above referred specification, like the following specification relates to the sole shaped disc 1 which is shown in FIG. 2, being however understood that the same strokes occur in connection with the second shaped disc.
When the vane 6 closes the port 23 and this occurs at 45° with respect to the top line L, the vane 7 is at the commencement of the delivery port 28 and the delivery of the liquid included between the vanes 6 and 7 begins, as the space defined by said vanes decreases in volume. The same fact, simultaneously occurs for the delivery port 27.
Accordingly, for each revolution of the rotor there are four suction strokes through the port 23 and four suction strokes through the port 24. Simultaneously there are four delivery strokes for each of the delivery ports 27 and 28.
As the shaped discs are two, for each complete revolution of the rotor there are sixteen suction strokes and sixteen delivery strokes originating a very regular delivery flow.
The vanes 6, 7, 8 and 9 could also be located tangent to a cylinder co-axial with the axis of rotation.
From the above disclosure appear evident the advantages of the pump according to this invention, deriving from the simultaneous displacement and centrifugal action exerted on the liquid, allowing values of rate of flow and of head to be obtained which are remarkable higher than those which can be obtained, at parity of conditions, by a pump of conventional type.
It is also to be noted that the device according to this invention, subject to suitable changes which can be planned by a person skilled in the art, is also capable of other embodiments, f.i. rotary motor, hydraulic drive, compressor, turbine and so forth.
The present invention has been described in one embodiment at present preferred, being however understood that constructive changes could be practically adopted without departing from the scope of the present industrial privilege.