GB2218469A

GB2218469A - Rotary apparatus

Info

Publication number: GB2218469A
Application number: GB8911061A
Authority: GB
Inventors: David Ross Millar
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-05-13
Filing date: 1989-05-15
Publication date: 1989-11-15
Also published as: GB8911061D0; GB8811396D0

Abstract

The apparatus comprises a housing (2) and an eccentric rotor (3) having blades (5) slideable in slots (4) to engage the housing (2) to define variable volume chambers. The blades are provided with seal members (6) each having a distal face (61) of a shape complementary to the interior face of the housing (2). The proximal face (60) of the seal member (6) and the distal end of the blade (5) are shaped to permit rocking movement of the seal member with respect to the blade. The apparatus may be an internal combustion engine, a pump, or a compressor. <IMAGE>

Description

A Rotary Apparatus This invention relates to a rotary apparatus and, in particular an internal combustion rotary engine.

The rotary engine is an internal combustion engine comprising a cylindrical housing, mounted within which is a cylindrical rotor. The rotor has cut into it a number of radial slots, into which fit blades that slide out to meet with the inner surface of the housing thus forming variable volume chambers. As the blade surface exposed to each chamber interior is a different depth (depending on the angular position of the rotor) the forces transmitted by the pressure of the combustion products will cause the rotor to revolve.

The main problem encountered with this type of engine is effecting a good seal between blade "tip" and the. interior surface of the housing.

This problem may also be encountered in other rotary positive displacement apparatus.

According to the present invention there is provided a rotary apparatus comprising a housing disposed within which is a rotor containing a plurality of slots which sealably and slidably receive a plurality of blades the distal ends of which sealably and slidably meet with the interior face of the housing forming variable volume chambers, dependant on the angular position of the rotor, said distal end of each blade being provided with a seal member which has a distal face which complements the interior face of the housing and a proximal face of a form which complements and which is moveable so as to rock on a curvature of said distal end of the blade, compelling the seal to remain in full surface contact with the inner surface of the housing at any angular position of the rotor with respect to the housing.

Preferably, the distal face of the seal member is in the form of a relief radius complementary to the curvature of the interior face of the housing.

The curvature on the blade end is preferably a convexity in the form of an axial groove of semi-circular section; the seal member preferably comprises therefore a seal strip with a complementary proximal face of semi-circular form, the strip being able to rock therefore within the groove, the radius of the groove being such that the distal relief radius of the seal member will remain seated on the interior of the housing at any angular position of the rotor in respect to the housing.

Preferably, the seal member is held in place by the outward urging of the blade against the housing.

Preferably, the seal member is sacrificial.

The biassing means may be in the form of a coiled spring or springs, or pressurised fluid either gas or liquid, which acts on the blade base, causing the blade to be urged outwards.

Preferably, in the rotary apparatus the air for combustion is introduced into the combustion chamber under pressure from an auxiliary blower and the fuel is introduced to the combustion chamber by direct injection. The ignition may be initiated by an incandescant spark and there may be no compression of the combustion air whilst in the combustion chamber.

Preferably, pressurised biassing fluid is the primary source of lubrication of the moving parts of the rotary apparatus.

The lubricant may be introduced with the combustion air or in the pressurised biassing fluid.

Preferably, the pressurised biassing fluid is the primary medium for the cooling of components of the apparatus.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a cross-sectional view of rotary apparatus having a seal for the rotary apparatus according to the present invention; and, Fig. 2 is a longitudinal sectional view of the apparatus of Fig. 1.

Referring to the drawings, there is provided rotary apparatus 1, which comprises a housing 2 having a hollow, cylindrical interior within which is a piston unit in the form of a rotor 3 having four radially arranged slots 4.

The slots 4 contain blades 5, the dimensions of which are such that there is little clearance between each blade 5 and its corresponding slot 4. The blades divide the interior into four chambers A, B, C, D. The blades 5 are slidably mounted within the slots 4 and urged outwards such that their distal edges slidably and sealably meet the interior face of the housing 2.

The blades 5 are urged outward by compressed gas or pressurised hydraulic fluid in the space E.

The distal edge of each blade 5 is provided with a seal strip 6, the strip 6 having a distal face 61 that complements the interior face of the housing 2 and being of a proximal form which complements and is movable so as to rock on a curvature of the end of the blade 5. The curvature is in the form of a groove 8 running axially along the length of the distal edge of the blade 5.

The seal strip 6 has an axial dimension equivalent to that of the blade 5, and its proximal surface 60 is semi-circular and of a radius equivalent to the distance between the blade corner and a point on the inner surface of the housing where it is inserted by projecting a line from the centre point of the rotor 3 along the centre of the width of the blade 5. A corresponding curve is machined on the end of the blade 5 to allow the seal strip 6 to seat on the end of the blade 5 in full surface contact. The distal face 61 of the seal strip 6 is machined to a curvature to seat against the inner surface of the housing 2, again with full surface contact.

The seal strip 6 is constructed thus because the tangent of the interior face is not always parallel to the tangent of the rotor 3 on the same axial line; there are only two points where the tangents are parallel. The seal strip made as hereinbefore will allow full surface contact between the blade 5, the seal strip 6, and the inner face of the housing 2 at all angular positions of the rotor 3.

As the rotor 3 rotates each blade 5 passes an induction port; as each blade 5 continues round, the space it leaves behind is filled by an air/fuel mixture either by induction or by way of an auxiliary blower. As the next blade 5 passes the induction port the induction of the mixture ceases and ignition should be initiated as soon as possible.

As the ignition process takes place the pressure in the chamber increases and by virtue of differing areas exposed to the chamber by the blades 5 a resultant force is produced causing the rotor 3 to revolve. As the rotor 3 revolves the chamber size increases and the differential of exposed blade 5 areas decreases to a point where any further rotation of the rotor 3 would cause the resultant forces to retard the rotation of the rotor 3, it is at this point or just before that the exhaust port will be uncovered by the leading blade 5 and the pressurised combustion products can escape, either to the atmosphere or be used to drive an auxiliary blower.

As the rotor 3 revolves further the chamber size is decreased and this decrease in volume is used to expel all the combustion products from the chamber ready for a fresh charge. The other chambers and corresponding blade pairs go through the same cycle as described above, providing an almost constant torsional force on the rotor 3 and consequently on the output shaft as there will be a certain amount of overlap of the cycles.

Cooling is effected either by a separate cooling system with an independent cooling medium, or by means of the pressurised fluid in the space E, ie introducing cool pressurised fluid to displace the fluid heated by the combustion process. If a hydraulic fluid is to be used then it may also be possible to use this as the lubricant for the internal components; oil could be introduced into the compressed gas, if this is the chosen method of pressurisation. Alternatively oil could be introduced with the air/fuel mixture for lubrication purposes.

A pressurisation fluid to provide the outward urging force to keep the seal effective is preferred but not essential; the blades 5 can be urged outwards by means of centrifugal force alone. However, some form of outward biassing of the blades 5 is preferable in practice to ensure contact is maintained between the blade 5, seal strip 6 and housing's 2 inner surface. The biassing means would also ensure the seal strips 6 remained in alignment. When the rotor 3 is at a standstill, it would be necessary to have either outward biassing means in the form of pressurised fluid and/or springs 10 (see Fig. 2) or instead of biassing means by the attachment of the seal strip 6 to the blade 5. The attachment may be by an axial key (not shown) which would be of a shape and clearance to allow the seal strip 6 to rock on the blade 5 end, or by recessed screws engaged through radial, counterscrews slots (not shown) in the seal strip 6 and blade 5 end.

The seal strip 6 of the present embodiment can be used on any rotary apparatus requiring a seal between the distal edge of a projecting extension and the inner face of its housing. The arrangement is also applicable when the blades and slot are not radially disposed but offset slightly or if the blades, rather than being inserted into slots, are pivoted at one end to the periphery of the rotor.

Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims

1. A rotary apparatus comprising a housing disposed within which is a rotor containing a plurality of slots which sealably and slidably receive a plurality of blades the distal ends of which sealably and slidably meet with the interior face of the housing forming variable volume chambers, dependant on the angular position of the rotor, said distal end of each blade being provided with a seal member which has a distal face which complements the interior face of the housing and a proximal face of a form which complements and which is moveable so as to rock on a curvature of said distal end of the blade, compelling the seal to remain in full surface contact with the inner surface of the housing at any angular position of the rotor with respect to the housing.

2. A rotary apparatus according to Claim 1, in which each blade is biassed outward towards the inner surface of the housing.

3. A rotary apparatus according to Claim 2, in which the blade biassing means is in the form of a spring or springs or apressurised fluid.

4. A rotary apparatus according to any preceding Claim, in which the curvature of the blade end is a convexity in the form of an axial groove of semi-circular section.

5. A rotary apparatus according to Claim 4, in which the seal member comprises a seal strip with a complementary proxiaml face of semi-circular form.

6. A rotary apparatus according to Claim 2, in which the seal member is held in place by the outward biassing of the blade against the inner surface of housing.

7. A rotary apparatus according to any preceding Claim, in which the seal member is sacrificial.

8. A rotary apparatus according to any preceding Claim, in the form of a rotary engine.

9. A rotary engine according to Claim 8, in which combustion air is introduced into the variable volume chambers under pressure from an auxiliary blower.

10. A rotary engine according to Claim 8 or Claim 9, in which fuel is introduced into the chambers by direct injection.

11. A rotary engine according to Claim 9, in which there is no compression of the combustion air whilst in the chamber.

12. A rotary apparatus according to Claim 3, in which the pressurised biassing fluid is the primary source of lubrication of the moving parts.

13. A rotary engine according to any of Claims 8 to 11, in which a lubricant is introduced into the apparatus with the combustion air.

14. A rotary apparatus according to Claim 3, in which the pressurised biassing fluid is the primary medium for cooling the components of the apparatus.

15. A rotary apparatus substantially as hereinbefore described with reference to the drawings.