GB2154283A

GB2154283A - Rotary fluid-flow machine

Info

Publication number: GB2154283A
Application number: GB08503566A
Authority: GB
Inventors: Philip Collier
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-02-18
Filing date: 1985-02-12
Publication date: 1985-09-04
Also published as: GB8503566D0; GB8404335D0

Abstract

A pump, compressor or, as shown, a motor comprises a rotor 10 mounted for rotation in a casing 14 which, with the rotor periphery defines a chamber 16 having a portion of constant radius, a portion of decreasing radius and a transition step 18 between said portions, the rotor having vanes 20 pivotally mounted thereon at its circumference and intended to be thrown out against the chamber outer wall by the action of centrifugal force to define compartments to which, in the case of the motor compressed gas is supplied to rotate the rotor, or in the case of a compressor (Fig. 3) low pressure gas is supplied to be compressed when the rotor is driven. The vanes need not touch the chamber outer wall. Such motor and compressor may be mounted on a common shah and associated with a combustion chamber to form an engine. <IMAGE>

Description

SPECIFICATION Improvements in or relating to fluid machines The present invention concerns improvements in or relating to fluid machines, for example fluid motors and pumps or compressors.

There have been many proposals in the past relating to fluid machines comprising a casing with a rotor rotatably mounted therein, the casing defining around the periphery of the rotor a "scroll" chamber which has a section of constant radius and a section of decreasing radius. Vanes are mounted in slots formed in the rotor periphery for sliding movement into or out of the rotor to define a plurality of compartments in the chamber, the compartments having a constant volume over that section of the chamber having a constant radius but a decreasing volume over the remainder of the chamber.

A disadvantage of these prior proposals resulted from the forces and stresses applied to the sliding vanes, the problems of sealing of the vanes relative to the casing and the problems of wear at the vane tips.

It is an object of the present invention to obviate or mitigate these disadvantges.

According to the present invention there is provided a fluid machine comprising a substnatially cylindrical first part disposed within a second part; the first and second parts being rotatable relative to one another about the axis of the first part and defining a chamber therebetween, the chamber including a converging section where a portion of the second part extends progressively inwardly, the first part being provided with a plurality of vanes pivotally mounted thereon so as to be capable of extending into the chamber, the vanes in use acting upon or being acted upon by the working medium.

Preferably the first part is a rotor, rotatable relative to the second part which is a casing.

Desirably the vanes are so mounted that they pivot away from the rotor under the action of centrifugal force and when fully opened touch the internal surface of the casing, or extend across substantially the whole of the chamber.

One face of each vane is preferably arcuate so that when the vane lies against the rotor when passing through the converging section said face is co-incident with the surface of the rotor.

Preferably the other face of each vane is flat. Preferably a boss is formed at the root of each vane to receive a pivot pin for the vane.

Preferably side plates are mounted on the rotor, the side plates supporting therebetween the pivot pins on which the vanes are pivotally mounted. The ends of the pivot pins may be tapered to form a force fit in the side plates. The side plates preferably are mounted in cylindrical recesses in the casing. The side casing preferably carry bearings, for example, ball bearings for the rotor shaft. Means are provided for supplying lubricant to the bearings, said lubricant passing into the chamber by way of oil-ways in the pivot pins and vanes. Oil seals are preferably provided between the peripheries of the side plates and the casing.

The vanes may be mounted on the pivot pins by means of sleeves or roller bearings.

An internal combustion engine may be provided by mounting two similar machines sideby-side relationship with a common drive shaft, one of said machines operating as a compressor compressing air which is then fed into the other machine acting as a motor via a combustion chamber.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 shows a sectional elevation of a fluid motor taken on the line I-I of Fig. 2; Figure 2 shows a sectional elevation taken on the line ll-ll of Fig. 1; and Figure 3 shows a sectional elevation of a compressor.

In Fig. 1 there is shown å motor having a cylindrical rotor 10 mounted for rotation on shaft 1 2 supported by bearings 1 3 in a casing 14. The casing defines a chamber 1 6 which has a constant radius over two thirds of its circumference and progressively reducing radius over the remaining third, there being an arcuate transition step 1 8 between the smallest and greatest radii. Six vanes 20 having arcuate leading faces and flat rear faces are pivotally mounted on the rotor and are equally spaced over its circumference, the vanes in -operation being thrown outwardly by centrifugal force and by the force of the working medium such that their tips slide over the internal surface of the casing.

The means of mounting the vanes 20 can best be observed in Fig. 2. Two circular side plates 22 are fixed to the end faces of the rotor 10, the diameter of the plates 22 being equal to that of the rotor. Pivot pins 24 having tapered ends extend between the plates 22 and carry sleeve or needle bearings by which the vanes 20 are pivotally mounted on the pivot pins, the vane roots being provided with enlarged bosses to receive the pins.The side plates 22 are each mounted in a cylindrical recess 26 formed in the casing 1 4. Lubricating oil is fed into the chamber 26 by way of an oil or grease inlet 28 leading to the bearing 1 3 and oil-ways are provided through the pivot pins 24 so that lubricating oil fed to the bearings may pass through radial oil holes (not shown) into the chamber 1 6 such that the vane tips in contact with the chamber surface are also lubricated. The vane tips are radiused.

Oil seals 28 are provided at the edges of the side plates.

An inlet channel 30 for supplying compressed working fluid to the chamber 1 6 is provided at the start of the section of greatest radius and an outlet channel 32 for exhausting fluid lead from the chamber at a point approximately diametrially opposite to the inlet.

Recesses 34 are provided in the outer surface of the rotor 10 to accommodate the vanes 20 when they are moving past the area of the chamber of minimum radius.

In operation, high pressure working fluid is supplied through the inlet 30, which extends over at least part of the transition step 18, into the chamber and causes the rotor to rotate in the direction of arrow A. The vanes 20 progressively pass the step 1 8 so that a continuous motion is provided and the vanes eventually arrive at a portion of reducing diameter during which the volume of fluid trapped between adjacent vanes is reduced, the vanes pivot rearwardly towards the rotor and the compressed air escapes beyond the following vane, the pressure of this air assisting the return of the vane to its retracted position.

Fig. 3 shows a modified arrangement based on the same principle as the arrangement shown in Figs. 1 and 2 but acting as a compressor. In Fig. 3 the rotor 50 rotates in the direction of arrow B with the vanes inclined forwardly in the direction of rotation.

The rotor is mounted on a shaft 52 in a casing 54 which has a portion of constant radius, a portion of converging radius and an arcuate transition step 58. Fluid is introduced into the chamber 56 by way of an inlet port 60 in the constant radius portion just after the step 58 and compressed fluid leaves the chamber by way of an outlet port 62 in the converging radius portion just before the step 58. The rotor 50 is driven in the direction of arrow B and it will be realised that a charge of fluid introduced into the part of the chamber defined by two adjacent vanes 58 is carried round the chamber until it passes through the section of reducing radius during which time the volume of the chamber is decreased so that the fluid therein is compressed until eventually the charge is in communication with the outlet 62 so that compressed fluid may exit from the compressor.

By connecting the motor of Fig. 1 side-byside with a compressor as shown in Fig. 3 and mounting the rotors thereof on a common shaft, an internal combustion engine may be provided. The outlet 62 from the compressor is connected to the inlet 30 to the motor and a combustion chamber is interposed in the connection so that fuel may be supplied and ignited in the combustion chamber thereby increasing the pressure of gas sufficiently to drive the rotor assembly.

In a simple version of the internal combustion engine arrangement the combustion chamber is provided in the motor (Fig. 1) by supplying fuel by way of a swirl nozzle (not shown) in the inlet 30 and a spark igniter in the chamber 1 6 adjacent the transition step 18.

Various modifictions can be made without departing from the scope of the invention. In one modification more or less vanes than the six vanes shown in the illustrated embodiments may be provided. The illustrated embodiments each show casings with one section of decreasing radius and one step. Two or more sections and steps may be provided to give a casing with multiple "scrolls", each scroll having an inlet and outlet port.

In another modification the vanes may be hollow to reduce their weight. The flat face of the vanes may be replaced by an arcuate face.

The vanes may have a length which is such that on full extension away from the rotor they do not touch the chamber wall, those regions of the chamber of constant radius. In a further modification outward pivotal movement of the vanes is restricted by their abutment with a stop on the rotor. The vane width may be less than the width of the chamber so that a turbine effect may be achieved as a result of compressed gas escaping past the vanes.

Such clearances are preferably greatest over the non-converging portions of the casing.

Claims

1. A fluid machine comprising a substantially cylindrical first part disposed within a second part; the first and second parts being rotatable relative to one another about the axis of the first part and defining a chamber therebetween, the chamber including a converging section where a portion of the second part extends progressively inwardly, the first part being provided with a plurality of vanes pivotally mounted thereon so as to be capable of extending into the chamber, the vanes in use acting upon or being acted upon by the working medium.

2. A machine as claimed in claim 1, in which the first part is a rotor, rotatable relative to the second part which is a casing.

3. A machine as claimed in claim 1 or claim 2, in which the vanes are so mounted that the pivot away from the rotor under the action of centrifugal force and when fully opened touch the internal surface of the casing.

4. A machine as claimed in claim 1 or claim 2, in which the vanes are so mounted that they pivot away from the rotor under the action of centrifugal force and when fully opened extend across substantially the whole of the chamber.

5. A machine as claimed in any one of the preceding claims, in which one face of each vane is arcuate so that when the vane lies against the rotor when passing through the converging section said face is co-incident with the surface of the rotor.

6. A machine as claimed in claim 5, in which the other face of each vane is flat.

7. A machine as claimed in any one of the preceding claims, in which a boss is formed at the root of each vane to receive a pivot pin for the vane.

8. A machine as claimed in claim 7, in which side plates are mounted on the rotor, the side plates supporting therebetween the pivot pins on which the vanes are pivotally mounted.

9. A machine as claimed in claim 8, in which the ends of the pivot pins are tapered to form a force fit in the side plates.

10. A machine as claimed in claim 8 or claim 9, in which the side plates are mounted in cylindrical recesses in the casing.

11. A machine as claimed in claim 8, claim 9 or claim 10, in which the side plates carry bearings for the rotor shaft.

12. A machine as claimed in claim 11, in which means are provided for supplying lubricant to the bearings, said lubricant passing into the chamber by way of oil-ways in the pivot pins and vanes.

1 3. A machine as claimed in any one of claims 8 to 12, in which oil seals are provided between the peripheries of the side plates and the casing.

1 4. A machine as claimed in any one of claims 7 to 13, in which the vanes are mounted on the pivot pins by means of sleeves or roller bearings.

1 5. An internal combustion engine comprising two machines as claimed in any one of the preceding claims mounted with their rotors on a single shaft, one of said machines operating as a compressor compressing air which is then fed into the other machine acting as a motor via a combustion chamber.

16. A fluid machine substantially as hereinbefore described with reference to Fig. 1 and 2 or Fig. 3 of the accompanying drawings.

1 7. An internal combustion engine substnatially as hereinbefore described with reference to Figs. 1 and 2 or Fig. 3 of the accompanying drawings.