GB2053359A - A Rotary Positive-displacement Fluid-machine - Google Patents

Abstract

A machine of the rotary- abutment kind that maybe an engine, a pump, a compressor or a brake has a rotor (15) carrying a radial piston (154) and revolving about the axis (AA1) of an annular chamber (21), the rotor being geared to a rotary "obturator(s)" (17A, 17B) that rotate(s) in a sealing chamber(s) about an axis (e) (BB1, CC1) and has (have) a recess to allow the piston to pass during rotation. The machine is characterised in that the piston (154) has a frusto-conic peripheral surface (G1, G2) that engages with a frusto-conic surface of the annular chamber, the two surfaces being kept in sealing contact with each other by a force due to e.g. a compression spring (23), acting along the axis (AA1). <IMAGE>

Description

SPECIFICATION A Rotary Fluid Machine, Such as an Engine, a Pump, a Compressor, a Brake This invention relates to a rotary fluid machine of the kind (hereinafter referred to as the kind set forth) comprising a rotor carrying a piston member that rotates continuously when the machine is in operation about the axis of an annular chamber, the piston member is mechanically linked to a rotary obturator that rotates in a sealing chamber about an axis substantially parallel to said axis of the said annular chamber and the rotary obturator has a recess into which a part of the piston enters during rotation to provide a working section in the cylinder as working fluid is fed to the piston.

The term fluid machine is to have a wide meaning to embrace inter alia an engine, a pump, a compressor or a brake in which work is done.

Such rotary fluid machines are known for example from the specifications of United Kingdom Patent Specifications No. 365,520 to Elrickand No. 407,661 to Societe Les Turbo Moteurs Guy and from United States Patent Specification No. 3,354,871 to Skrob. It has proved exceptionally difficult to seal the rotary obturator and without effective sealing the engine is inefficient and this difficulty is fully explained by Skrob (3 17-21).

According to the present invention there is provided a rotary fluid machine of the kind set forth wherein the piston member has a frustoconical peripheral surface that seals with a frustoconical mating surface of the annular chamber, the two frusto-conical surfaces are kept in sealing contact by an axial force that is directed along the axis of a right cone common to both said frustoconical surfaces, the axis being the axis of rotation of the piston member.

In one arrangement the rotary obturator is also of frusto-conical form and axially forced into sealing contact with its sealing chamber that is of complimentary shape. Alternatively the rotary obturator may be one of the divided forms described in my co-pending application No.

8019575.

The invention will be more fully understood from the following description given by way of example only with reference to the figures of the accompanying drawings in which: Figure 1 is an elevation in section of a rotary machine of the invention, and Figure 1 A is a part section of the piston and cylinder in mating contact.

Figure 2 is a part section similar to Figure 1 of an alternative arrangement to a larger scale.

Figure 3 is a view in perspective of a part of a piston and one rotary obturator of an alternative construction and Figure 3A is a detail in section.

Referring now to Figure 1 a block 10 has a head 11 spigot jointing at 12 and carrying a centraily journalled power shaft 13 in bearings 14,, 142 and 143. The shaft 13 carries a rotary piston member 1 5 keyed at 15, and splined at 152 to said shaft with allowance for movement of the key at 153. The piston has three working piston parts of which one only is shown at 1 54 said piston entering a piston recess such as 1 6 in rotary obturator 1 7A of a diametrally opposed pair, its fellow obturator being at 1 7B. Each rotary obturator is keyed at 181, 182 and splined if necessary to a shaft 19,,192, each key is provided with an allowance for movement of the shaft at 183,184. Gears 201,202on shafts 19,, 192 mesh with gear 203 on shaft 13 that has a power output end at 13,.

Steam or other suitable working fluid is fed to annular chamber and expansion cylinder 21 containing the rotary piston 1 5 by means of a metering unit shown generally at 22. Any suitable metering unit may be used and one such unit is described in my co-pending Application No.

8019575.

Rotary piston 1 5 has a frusto-conical peripheral sealing surface 1 5A that seals with a like frusto-conical sealing surface at 1 5B of the wall 21, of the annular chamber 21 shown inset in Figure 1A and taken at a section station away from the rotary obturators. Mating surfaces 15A, 15B are each part of a common right cone having its axis on the axis AA, of shaft 13 as represented by the single incomplete generator G1, G2.

Suitable clearance for take-up of wear is left at position CL,.

The rotary piston 1 5 is spring urged along the axis AA, by helical compression spring 23.

Similarly frusto-conical rotary obturators 17A, 1 7B are individually spring urged by helical compression springs 24A, 24B along the axis BBr, respective 2 CC, of their respective shafts 19" 19 so that said obturators 1 7A, 1 7B seal against complimentary mating frusto-conical surfaces of their respective sealing chambers and thus with wear the all important seal is efficaciously maintained, a suitable clearance being left at position CL2, CL3.

In an alternative construction the spring force may be dispensed with and fluid pressure used to urge the surfaces into mating contact.

In Figure 2 a rotary obturator shown generally at 1 7C is of a form described and claimed in my co-pending application No. 8019575. The rotary obturator has two parts 1 7C1, 172 that are spring urged by a spring not shown helically along line 25 to expand continuously and thus effect good sealing at all times, irrespective of wear and thermal expansion with the internal surfaces of its sealing chamber. The piston rotor 15 as in Figure 1 mates on frusto-conical surface of a common right cone shown by the single generator G3, G4 that meets when extended on the centre line AA1 of piston shaft 13.

In Figure 3 a piston 26 of a different construction from that of Figures 1 and 2 is of a singularly robust form. The piston 26 has an internal piston face 26A co-operating with a piston recess 27A in a separable rotary obturator shown generally at 1 7D that is able continuously to expand on a helical surface 28 so that surfaces 291, 292 always mate with the surfaces 26i, 262 of the piston 26. It is to be noted that the piston surface 30 is also frusto-conical to mate with a similar surface 31 of the obturator (Figure 3A).

The piston also has a frusto-conical sealing surface at 32 that mates with a similar wall surface (not shown). The piston member is provided with a piston working part 26A annularly enclosed on three sides 26" 262, 26; the obturator sealing with two of the said opposed sides viz: 261, 262.

Claims (11)

Claims

1. A rotary fluid machine of the kind set forth wherein the piston member has a frusto-conical peripheral surface that seals with a frusto-conical mating surface of its annular chamber, the two frusto-conical surfaces are kept in sealing contact by an axial force that is directed along the axis of a right cone common to both said frusto-conical surfaces the axis being the axis of rotation of the piston member.

2. The rotary fluid machine according to claim 1, wherein the rotary obturator is of a frustoconical form and forced axially into sealing contact with its sealing chamber that is of a complimentary form.

3. The rotary fluid machine according to claim 1 wherein the rotary obturator is made of at least two parts that are continuously urged along an incline to keep at least a part of the exterior surface of the obturator in sealing contact with the juxtaposed interior surface of its sealing chamber.

4. The rotary machine according to claim 3 wherein the incline is a helical surface.

5. The rotary fluid machine according to claim 1 or claim 2 wherein the said frusto-conical surfaces are spring urged into mating contact.

6. The rotary machine according to claim 1 or claim 2 wherein the said frusto-conical surfaces are urged into mating contact by fluid pressure.

7. The rotary fluid machine according to claim 4 wherein one of the frusto-conical surfaces of any mating pair of such surfaces is attached to a splined shaft allowing axial movement of said shaft.

8. The rotary fluid machine according to claim 1 wherein the piston member has piston working parts annularly enclosed on three sides, the obturator sealing with two opposed sides of the said sides of the annulus.

9. A rotary fluid machine constructed and arranged substantially as described herein and as shown in Figures 1 and 1A of the accompanying drawings.

10. A rotary fluid machine according to claim 9 when modified as shown in Figure 2.

11. A rotary fluid machine according to claim 9 when modified as shown in Figures 3 and 3A.