GB2158516A - Rotating pump with oscillating vanes - Google Patents

Abstract

To maintain an extremity of each vane 21 constantly in contact with or close to the internal cylindrical surface of the stator 16, 16', cyclic variation of vane projection relative to the cylindrical surface of the rotor, is determined by cyclic oscillation of each vane with its shaft 10 said oscillation being guided and controlled by a special guiding device 24 to 27. The device comprises an offset pin 25 with a bearing 24 rolling around a track 27. Due to centrifugal force in use, a mass 26 assists in keeping the vanes in the best position. An adjusting screw 30 and adjustable reaction spring 32 provide means for varying the degree of eccentricity between the rotor and stator. <IMAGE>

Description

SPECIFICATION Variably eccentric rotating pump with oscillating vanes Background of the Invention The most well-known pumps on the market are those driven by a piston, by-gears or by vanes.

Though the piston pumps give an excellent output in volume, and though the heads produced are high, their systems for varying cyclic delivery are of considerable complexity.

Gear pumps are relatively expensive and no variation can be made to cyclic delivery.

Radial-vane pumps have a big problem over seal and consequently can only achieve low levels of pressure and efficiency. They are also delicate, the oil liable to pollution by metal particles and a high number of revolutions must be obtained for priming.

The invention here described eliminates the above drawbacks, at the same time offering considerable advantages as will be explained below.

Summary of the Invention In pumps worked by rotating vanes, in which rotor and stator are eccentrically placed, the position of the vanes in relation to the rotor must vary in a certain sequence to ensure that said vanes shall always be maintained in an optimum position; in other words their extremities must at all times be kept in contact with, or very near to the inside cylindrical surface of the stator.

Bearing rotor and stator eccentricity in mind, in accordance with a certain sequence, projection of a vane must vary in relation to the cylindrical surface of the rotor at each turn made by the vane.

According to this present invention the desired variation is achieved by oscillation of each vane, around its own shaft parallel to that of the rotor and supported by it, by means of a special guide device which reacts to pressure of the fluid exerted on the vane itself.

In a preferred execution said device comprises a small arm fixed eccentrically to each vane's shaft and so arranged that its geometrical axis is practically in line with the extremity of each vane.

Said arm is fitted with a sliding means, such as a roller bearing or some other, on a circular track that is coaxial with and fixed to the stator, said track therefore automatically adapting itself to any variation there may be in eccentricity between stator and rotor, and guiding and regulating oscillation of the vanes.

The rotor substantially consists of two cylindrical sides connected by an intermediate body, also cylindrical, of a suitably smaller diameter.

In the ringwise cavity formed by the difference in diameters the cylindrical part of the stator can be loged and said part is counterposed to the central body of the rotor.

A set of holes is made in the rotor; said holes are parallel to its shaft, at an equal distance from it and all set at the same angle, and in the central cylindrical zone of the rotor said holes are open in the direction opposite to the axis of the rotor in such a way as to communicate with the ringwise cavity which is formed between rotor and stator.

In the cylindrical holes are lodged the cylindrical oscillating shafts of the vanes made by a flattening process applied to the central area of said shafts, at a short distance from their geometrical axes opposite the position of the circular cavity between rotor and stator.

The flat parts of the vanes form surfaces for withstanding pressure by the fluid, while the convex parts from the rear that slides back and forth in the rotor seats.

An eccentric mass is fixed to each shaft that forms a vane, said mass being set in an angular position such as will create centrifugal force tending to keep the bearing for the guiding and reacting arm towards the circular track, coaxial with and fixed to the stator, and so to keep vane extremities directed towards the internal surface of the stator.

The stator can translate in relation to the rotor thus varying their eccentricity and consequently the size of the chambers which form in sequence between the vanes and the counterposed cylindrical surfaces of the rotor and the stator, also varying cyclic delivery of the pump as a result.

Stator translation further determines that of the coaxial circular track along which moves the guiding and reacting arms fixed to the vanes.

The extent of stator translation is determined by the thrust set up by a screw part counterposed to a reacting spring through which eccentricity can be minutely and accurately regulated.

In a preferrred execution the rotor consists of a single piece while the stator is in two pieces and this enables it to fit into the space between the two cylindrical sides of the rotor. Seal between the convex part of the vane and the semicirular seat in the rotor, where in it moves back and forth, is ensured by a longitudinal gasket placed inside a slot made in said convex part.

Contact between the internal cylindrical surface of the stator and the extremity of the vane takes place through the oil present on said extremity; the whole movement is made with minimum friction, and maximum smoothness and seal.

The characteristics and purposes of the invention will be made even clearer by the following examples of its execution illustrated by diagrammatic drawings.

Brief Description of the Drawings Fig. 1: perspective view of the pump.

Fig. 2: transversal view.

Detailed Description of the Preferred Embodiments The pump comprises a series of radial vanes 21 made by flattening an area in the central part of the shafts 10, essentially consisting of a cylinder lodged in the holes 51 in the body of the rotor 11 fixed to the shaft 12 rotating on bearings 13,14, Fig. 1.

Within the central ringwise cavity 15 made in the rotor, the stator is mounted, made in two halves 16, 16', with a flat base 17 sliding on rollers 18 resting on the bottom of the casing 19 by interposition of the block 20.

The shafts forming the vanes are supported on both sides by the roller bearings 22 and 23, and at one end have a reaction pin 25 with bearing 24 projecting off the end and placed eccentrically in relation to the geometrical axis of rotation of the vane 21 and balancing mass 26.

The bearing 24 rolls round the circular track 27 with annular edge 28 coaxial to the stator and fixed to it by means of the cylindrical body 29 with closed end. On one side the stator 16 is in contact by means of the screw 30 screwed onto the cover 31 fixed to the casing 19. On the side opposite to the screw 30, the elastic reaction of the spiral spring 32, fitted inside the tube 33 fixed to the casing 19, is counterposed through the ring 35 on the plate 34 fixed to the rod 34'.

The load applied to the spring is adjusted by means of hand-wheel 36, screwed onto the tube 33, which passes on the spring through the interposed spacer ring 37.

Above the casing 19 there is a pipe union 38 communicating with the hole 39 in the stator through the short elastic tube 40.

In its lower part the stator has a series of holes 41 which lead into the pipe 42 communicating with the lateral pipe union 43 by means of the small interposed tube 44.

The linear extremities, such as 45 and 46, of two adjacent vanes, form a seal against the internal surface of the stator creating chambers, like 47 (Fig.

2) of variable volume as they move round.

The variation will be greater of smaller according to the degree of eccentricity between the rotor 11 and the stator 16, 16' in any one position.

The extremities 45,46 such as each vane has, are practically aligned with the axis 50 of the reaction pin.

There is a seal gasket 48 on the convex back of each vane. The fluid drawn into the pump enters through pipe union 38 and, passing through the hole 39, reaches the chambers 47 of varying volume where, due to rotor 11 rotation, it is compressed and sent into the delivery pipe 42.

Rolling along the track 27, the bearing 24 of the pin 25 on each vane offers resistance to pressure of the fluid in said vane.

Though oscillating cyclicly around the axis of shaft 10 at an angle determined by the degree of eccentricity between rotor and stator, due to the effect exerted by the pin 25 the vanes maintain their linear extremities, like 45,46, practically in constant contact with the internal cylindrical surface of the stator or at any rate very close to said surface.

If it is desired to vary the cyclic delivery of the pump, screw 30 is turned thereby altering the position of the stator 16, 16' and its eccentricity in relafion to the rotor 11, and therefore of the track 27; Due to centrifugal force, the balancing mass 26 co-operates with the bearing 24 in keeping the vanes continually in the best position.

Advantages A high head and great output in volume.

No vibrations.

Strong construction, great reliability and long life.

Cyclic delivery is easy to adjust.

Adjustments made to pressure and power take quick effect.

A wide range of applications with both a low and a high number of revolutions.

High ratio between volume of the chambers, overall dimensions and weight.

Constructional simplicity and low cost of production.

As applications of the invention have been described as examples only not limited to these, it is understood that any equivalent application of the inventive concepts explained and any product executed and/or in operation according to the characteristics of the invention, will be covered by its field of protection.

Claims (11)

1. Variably eccentric, vane-operated rotating pump characterized in that, to maintain linear extremity of the vane constantly in contact with, or in any case close to the internal cylindrical surface of the stator, cyclic variation of vane projection in relation to the cylindrical surface of the rotor is determined by cyclic oscillation of each vane on its shaft parallel to the rotor shaft and supported by it, said oscillation being guided and controlled buy a special guiding device reacting to pressure from the fluid.

2. Variably eccentric, vane-operated rotating pump as in claim 1, characterized in that the guiding and reacting device consists of a small arm, eccentrically fixed to the shaft of each vane, the geometrical axis of which is practically aligned with the linear extremity of said vane, the arm being provided with a means for sliding along a circular track coaxial and fixed to the stator in such a way that guide and control of vane projection out from the rotor is automatically suited to any variations in eccentricity between the stator and the rotor.

3. Variably eccentric, vane-operated rotating pump as in claim 1, characterized in that the rotor substantially consists of two cylindrical sides connected by an intermediate cylindrical body having a suitably smaller diameter and of a thickness such as to enable the stator to be placed within the resulting circular cavity, a set of cylindrical holes being made art a constant angle in the rotor, said holes being parallel to the shaft of the rotor and at an equal distance from it and being open at the point of the intermediate cylindrical body, at the opposite end in relation to the rotor shaft itself so as to communicate with the annular volume created between the stator and the rotor, said holes constituting the supports for the oscillating cylindrical shafts of the vanes formed by flattening at the central area of said shafts at a short distance from their geometrical axes and opposite the annular zone between the rotor and the stator.

4. Variably eccentric, vane-operated rotating pump as in claim 3, characterized in that each vane has a substantially semicircular constant transversal section, the flattened part constituting the surface that reacts to pressure from the fluid and the convex part constituting the back part that moves back and forth inside its seat in the rotor.

5. Variably eccentric, vane-operated rotating pump as in claim 1, characterized in that the rotor is made in a single piece while the stator is made of two pieces.

6. Variably eccentric, vane-operated rotating pump as in claim 1, characterized in that the stator can translate, in relation to the rotor, to vary the degree of eccentricity.

7. Variably eccentric, vane-operated rotating pump as in claim 6, characterized in that stator translation is determined by a screw means to which a reaction spring is counterposed.

8. Variably eccentric, vane-operated rotating pump as in claim 1, characterized in that the fluid, especially oil, that passes between the linear extremity of the vanes and the internal cylindrical surface of the stator, creates contact between vane and stator through the fluid with minimum friction and maximum smoothness.

9. Variably eccentric, vane-operated rotating pump as in claim 1, characterized in that the fluid is sucked in radially and expelled tangentially.

10. Variably eccentric, van-operated rotating pump as in claim 1, characterized in that a suitablysized eccentric mass is fixed to each shaft forming a vane, said mass being so placed as to create a centrifugal force that pushes the extremity of the vanes towards the internal cylindrical surface of the statorto co-operate with the guiding and reacting device against pressure from the fluid.

11. A pump substantially as herein described with reference to the accompanying drawings