US2442130A - Rotary fluid pressure motor, pump, and the like - Google Patents

Description

May 25, 1948. E. H; JOHNSON ROTARY FLUID PRESSURE MOTOR. PUMP, AND THE LIKE Filed lay 23; 1944 2 Sheets-Sheet 1 A Home y 1943- I E. H. JOHNSON 2,442,130

ROTARY FLUID PRESSURE MOTOR, PUMP, AND THE LIKE Filed May 25, 1944 2 Shasta-Sheet 2 l n uenlor W A i Home Patented May 25, 1948 ROTARY FLUID PRESSURE MOTOR, PUMP, Y AND THE LIKE Edward Harry Johnson, Coventry, England, as-

signor to The Keelavite Company Limited, Allesiey, Coventry, England, a company of Great Britain Application May 23,1944, Serial No. 536,973 In Great Britain June 10, 1943 4 Claims.

This invention relates to rotary fluid pressure motors, pumps and thelike, hereinafter termed "rotary engines" for the sake of convenience, adapted to operate upon or be operated by fluid whether gaseous or liquid, hereinafter termed the working fluid, and either employed primarily to act upon or be acted upon by the working fluid or employed as or incorporated in devices such as transmission devices or fluid meters.

The invention is concerned with rotary engines of the kind comprising a casing in which is provided an annular blade chamber, a rotor rotating about the axis of the blade chamber and having blades which extend across the blade chamber through slots in one end wall thereof and make a sealing fit with the inner and outer circumferential walls of the blade chamber and with the end wall hereinafter termed the non-rotating end wall" remote from that through which they extend, and one or more rotary abutments supported in bearings in a part rigid with the inner or outer circumferential wall of the blade chamber and each extending across the blade chamber between inlet and outlet ports and having a circumferential surface which is circular in planes at right angles to its axis of rotation and makes a sealing fit at all times with abutment recesses of part-circular cross-section respectively in the inner and outer circumferential walls of w the blade chamber, one or more blade-receiving recesses being provided in each abutment, each of which during rotation of the abutment comes into position to receive a blade and permit it to pass the abutment as the blade during its rotation comes to the part of the blade chamber across which the abutment extends. The capacity of the rotary engine is variable by moving the rotor axially together with the non-rotating end wall and that circumferential wall of the blade chamher which does not carry the abutment or abutments. Thus the non-rotating end wall moves axially towards or away from the rotating end wall to vary the capacity of the blade chamber while the blades slide through the slots in the rotating end wall so that their effective crosssection is similarly varied.

In such variable capacity rotary engines as previously proposed the inner and outer circumferential surfaces of the rotating end wall and of the parts of the blades lying within the slots therein at any time have made a fluid seal with two non-rotating parts hereinafter termed end wall sealing parts. one of which however is arranged to slide axially with the axially movable circumferential wall of the blade chamber so as always to be in the same axial relationship with the rotating end wall. The other end wall sealing part however is stationary with the result that, to maintain a fluid-tight seal at all times around the blade where it passes through the rotating end wall, the blades must be of the same crosssection throughout their length otherwise if for example their circumferential width were reduced towards their ends fluid could escape along the slots thus left between the blades and the sides of the slots through which they pass and then radially out behind the stationary sealing part referred to when the blades were so far withdrawn from the blade chamber that the portion of reduced width extended outwards beyond this stationary part.

In rotary engines of the kind referred to increases in the width of the blades necessitates correspondingly larger blade-receiving recesses in the abutment or abutments which in turn necessitate either reducing the sealing area of the abutment or increasing its diameter for a given sealing area. It is therefore desirable to maintain the width of the blades as small as is possible within the required degree of sealing efflciency and mechanical robustness of the blades. In variable capacity rotary engines of the kind in question however, the blades have to be comparatively long to allow for the required adjustment to vary the capacity of the engine while to obtain the required mechanical robustness especially for the high pressures at which such engines usually operate, with the present necessity for making the blades of the same cross-section throughout their effective length, entails making the blades considerably wider than is necessary for sealing purposes or compatible with compactness.

The object of the present invention is to provide an improved construction of variable capacity rotary engine of the kind referred to in which the above difliculty will be reduced or eliminated.

To this end in a variable capacity rotary engine of the kind referred to according to the present invention not only is the axial thickness of the rotary end wall suflicient as hitherto to make a fluid seal with at least a part of the length of the sides of the blades throughout their axial movement but the rotary end wall or a part rotating therewith extends radially beyond the circumferential surface of the blade chamber adjacent to the stationary end wall sealing part so that one of the circumferential surfaces of each blade is sealed by a part rotating with the rotary end wall and having a face which makes a fluid endof the stationary circumferential wall of the blade chamber. This enables blades to be employed which are of larger dimensions at the roots where they make a fluid-tight seal at their sides with the sides of the slots in the rotary end wall andvat their circumferential surfaces respectively with the part rotating with the rotary end wall as explained above and'with the non-rotating pa which moves axially with the rotor.

The invention is applicable to rotary engines of thekind referred to wherein the rotary abutment or abutments are carried either in the inner or the outer circumferential wall of the blade chamber but for convenience in the following description it will be described with reference to a construction in which they are carried in the outer circumferential wall.

In this case the inner circumferential wall is arranged-to move axially with the rotor and the axially movable end wall may be formed integral with the inner circumferential wall of the blade chamber. The rotating end wall is conveniently in the form of a cylinder having a radial thickness equal to the radial dimension of the blade chamber and provided with longitudinal slots in which the blades slide and from which they project into the blade chamber. In such an arrangement as at present made, the end of the cylinder constituting the rotary end wall proper lies and makes a-sealing fit with rotationally stationary parts, theinner one of.which. however,

slides axially with the rotor. When the present invention is applied to such a construction the rotary endwall extends radially outwards at the end of the blade chamber beyond the outer circumference thereof and has an end face making a sealing fit with a corresponding face on the adlacent end of the outer circumferential wall of the blade chamber and an outer circumferential surface which makes a sealing fit with a corresponding fixed circumferential surface. The outward extension of the rotating end wall is conveniently constituted by a ring tightly fitted to the outer circumference of the cylinder constituting the rotating end wall and terminating at the blade chamber end approximately flush with the end of the cylinder. The blades are then formed so that for a certain length from their roots they make a sealing fit with the sides of the slots in the cylinder, with the inner rotationally stationary part and with the ring referred to above while their outer ends, which extend into the blade chamber are of reduced width. Thus" the thickened root portions provide a more rigid support for the blades while the construction according to the invention permits this to be employed without the necessity for retaining the section of the stiffer part throughout the blade length with the consequent increase in weight and size of abutment or reduced abutment sealing area.

The invention may be carried into practice in various ways but one construction according to the invention is illustrated by way of example in the accompanying drawings, in which Figure 1 is a cross-section of a rotary engine according to this invention ina plane passing of the rotor and the comprises a casing A into one end of which exforming with the casing an annular blade cham-' ber C one end wall C and the inner circumferential wall 0 of which are, formed by the member C while the outer circumferential wall C is constituted by the casing A. The other end wall of the annular blade chamber (3 is arranged to rotate and is constituted by the free end of a cylin-. der D formed integral with a flanged hub D rigidly mounted on the driving shaft B.

Mounted in bearings E in the member C is a rotor comprising a hollow shaft E having a flange 'lil formed integral with one end thereof and carrying two blades 1!: lying in longitudinal slots in the cylinder D and extending therefrom across the blade chamber C so as to make a fluid-tight seal with, the inner and outer circumferential walls and the end wall C thereof. The hollow shaft E carries within it a bearing engaged by the end of an extension B" of the shaft B.

' Mounted to rotate within the casing about an axis parallel to that of the rotor is an abutment G disposed between inlet and outlet ports (not shown) in the blade chamber and. making a sealing fit at all times with abutment recesses respectively in the inner and outer circinnferential walls of the blade chamber in known manner and provided with blade-receiving recesses adapted to receive the blades as the rotor and the abutment rotate in synchronism when these blades come to the part of the blade chamber across which the abutment extends and thus permit the blades to pass the abutment. The synchronised rotation of the rotor and abutment is effected by gear wheels H and H secured respectively to the rotor shaft E and the shaft G of the abutment G, and arranged to permit the axial movement of the member C with the rotor.

The part C of the member C which constitutes the inner circumferential wall of the blade chamber extends within the free end of the cylinder D so as to make a fluid-tight Joint with its inner circumferential surface, while a ring J surrounds the cylinder D closely so as to make a sealing fit with the outer circumferential surfaces of the blades. The end of this ring J adjacent to the blade chamber also makes a fluid seal with the surface J extending radially outwards from the end of the blade chamber and with the length of the ring J being sufficient to maintain this seal throughout the axial movement of the member C and the rotor. The free ends of the blades, however, where they extend into the blade chamber are narrower as shown at E Thus while the root portions provide a rigid support for the effective parts E of the blades, these parts can be relatively narrow and only of such width as is dictated by considerations of fluid sealing and rigidity bearing in mind their short unsupported length compared with blades of similar width throughout their entire length as was previously necessary in order to maintain the necessary fluid sealing.

The outer circumferential surface of the ring J makes a fiuid seal a shown with a plate K rigidly mounted within the casing A.

What I claimas my invention and desire to secure by Letters Patent is:

1. A variable capacity rotary engine including in combination a casing, a rotor arranged to be movable axially within the casing and comprising a support and blades extending axially therefrom, an annular blade chamber having inlet and outlet parts and into and across which the blades extend and comprising inner and outer circumferential walls one of which is rigid with the casing while the other circumferential wall can move axially with the rotor, and end walls one of which rotates with the rotor and has slots therein through which the blades project into the blade chamber while the other end wall, with which the ends of the blades make a sliding fit, is fixed rotationally but movable axially with the rotor, abutment recesses of part-circular crosssection in the inner and outer circumferential walls, and at least one rotary abutment supported in bearings in a part rigid with the casing, extending across the blade chamber between the inlet and outlet ports and having a circumferen- 1 tial surface making a sealing fit at all times with rotary end wall not only has an axial thickness sufficient to make a fluid-tight seal with the root portion throughout the axial movement of the blades through the slots in the said rotary end 'wall but also has a part which extends radially beyond the circumference of the fixed circumferential surfaces of each blade to provide a surface making a fluid-tight seal with a corresponding surface on the adjacent end of the stationary circumferential wall of the blade chamber.

2. A variable capacity rotary pump including in combination a casing, a rotor arranged to be movabl axially within the casing and comprising a support and blades extending axially therefrom, the circumferential width of the root porhas slots therein from which the blades extend across the blade chamber and with which the sides of the root portions only of the blades make a sealing fit while the other end wall, with which the ends of the blades make a sliding fit, is fixed.

rotationally but slides axially with the rotor, abutment recesses of part-circular cross-section in the inner and outer circumferential walls, at

least 'one rotary abutment supported in bearings in a part rigid with the outer circumferential wall of the blade chamber, extending across the V blade chamber between inlet and outlet ports and having a circumferential surface making a 7 sealing fit at all times with the abutment recesses, at least one blade-receiving recess being provided in each abutment which during rotation comes into position to receive a blade and permit it to pass the abutment, and an annular part rigid with the rotary end wall and extending radially outward adjacent to the end of the blade chamber where not only does a surface on the said annular part make a sealing fit with a corresponding face on the end of the outer circumferential wall of the blade chamber, but it provides a circumferential wall with which the outer circumferential surface of each blades makes a sealing fit. I

3. A variable capacity rotary engine having the combination of elements claimed in claim 2, in which the annular part is constituted by a ring closelysurrounding and rigidly mounted on the outer circumference of the cylinder constituting the rotary end wall of the blade chamber;

4. In a variable capacity rotary engine comprising a casing providing an outer circumferential wall of an annular working chamber, a rotor mounted in the casing for axial as well as rotary motion, and an annular member mounted within the casing for axial movement with the rotor and fixed against rotation relative to the casing, the said annular member providing an inner circumferential wall and one end wall of the annular working chamber, the combination of a cylindrical member mounted within the casing for rotation with the rotor and fixed against axial movement, the said cylindrical member 1 tion of each of which blades is greater than that having an edge that provides a second end wall for the working chamber and the said cylindrical member being provided with slots that register with the chamber in axial alignment therewith, blades mounted on the rotor and comprising root portions slidably engaged within the slots of the cylindrical member and piston portions of lesser thickness than the root portions and that extend through the working chamber and slidably contact. the circumferential and first end walls thereof, and a sealing ring surrounding and secured to the cylindrical member and slidably engaging the outer surfaces of the portions of the blades within the slots of the said cylindrical member, the said ring extending axially from the wall-forming edge of the cylindrical member at least as far along the said cylindrical member as the position which can be reached by the inner ends of the root portions of the blades, and having a surface slidably engaging the casing to form a sealing contact with the outer circumferential wall structure of the chamber.

EDWARD HARRY JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,994,391 Loveridge et a1. Mar. 12, 1935 2,258,504 Booth .Oct. 7,1941

FOREIGN PATENTS Number Country Date 448,952 Great Britain June 18, 1936

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