AU742776B2

AU742776B2 - An air turbine motor

Info

Publication number: AU742776B2
Application number: AU10102/99A
Authority: AU
Inventors: Kenneth Douglas Horner
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-10-27
Filing date: 1998-10-27
Publication date: 2002-01-10
Anticipated expiration: 2018-10-27
Also published as: AU1010299A

Description

P:\OPER\LKA22862018 speci.doc412/l IA -1- AN AIR TURBINE MOTOR Field of the Invention This invention relates to air turbine motors. The invention has been particularly developed for use in a pneumatic starter motor and will be primarily described with reference to this application. The motor is however suitable for use in other applications where pneumatic motors are used due to the nature of the operating environment or otherwise.

Background Art Pneumatic starter motors are used for cranking internal combustion engines for starting purposes and are typically used for large engines and engines operating in environments where electric starting systems can be hazardous such Sas in mines.

5 Some known pneumatic starter motors have utilised a arrangement in which a flow of air generally parallel to the axis of rotation of a turbine wheel S' interacts with turbine elements to drive the wheel in rotation. In some other known pneumatic starter motors, air is directed radially with respect to the axis of rotation of a turbine wheel to interact with radially oriented elements which drive the wheel in rotation. Whilst both arrangements have been used to provide satisfactory air motors for pneumatic starters and other applications, improvements in output and operating characteristics are continuously sought.

Disclosure of the Invention It is an object of this invention to provide an improved air turbine motor.

Accordingly, this invention provides an air turbine motor including a turbine wheel mounted for rotation about an axis, a first set of elements displaced substantially around a circumferential outer edge of said turbine wheel and arranged to drive said turbine wheel in rotation about said axis in a first direction 0 substantially only in response to an axial flow of air a second set of elements displaced around said turbine radially inward from said first elements and arranged P:\OPER\LKA\2286211X speci.do-4)2/I IA01 -2to drive said turbine wheel in rotation about said axis in said first direction substantially only in response to a radially inward flow of air, and means to direct drive air to said first set of elements in an axially directed flow and stator means interposed between said first set of elements and said second set of elements to direct drive air emerging from said first set of elements to said second set of elements in a radially directed flow.

Preferably, the radially driven set of elements is arranged on a face of said turbine wheel.

The radially driven set of elements are preferably arranged in two consecutive stages whereby the drive air passes through one stage and then the other stage. The consecutive stages are preferably formed by arranging the elements in two concentric circular arrays.

The turbine wheel is preferably mounted between two stator arrangements.

The first of the stators directs drive air axially toward said axially driven elements 15 whilst the second stator re-directs air emerging from said axially driven elements in a radial direction to said radially driven elements.

o This preferred turbine stator configuration prevents a high side thrust loading on the turbine wheel. This is because the inlet air through the first stator exerts force which is opposite to the axial force developed by the air passing through the radially driven elements on the remote side of the turbine wheel.

Additionally, the configuration allows a very compact and easily assembled air turbine motor to be produced.

The air turbine motor according to this invention has been found to provide a superior power output for a given drive air input. This allows a corresponding reduction in the size of the motor to produce a given power output. The air turbine motor of this invention also as a higher stall torque, that is, torque at zero rpm.

This is particularly important for WO 99/22117 PCT/AU98/00890 -3applications to pneumatic starter motors since start load is frequently very high.

The use of multiple stages through the respective axial and radial elements also allows speed control of the turbine motor.

The invention will now be described, by way of example only, with reference to the accompanying drawings.

Brief Description of the Drawings Figure 1 is a schematic sectional view of an air turbine motor according to this invention; Figure 2 is an elevation of the turbine forming part of the air motor of Figure 1; and Figure 3 is a rear elevation of the turbine shown in Figure 2.

Best Mode for Carrying out the Invention As seen in the drawings, the air turbine motor 1 according to this invention comprises a housing 2 in which a turbine wheel 3 is mounted for rotation between an air inlet stator 4 and a second stator 5. An air inlet manifold 6 is provided in the housing in a known way.

Stator 4 has a series of sequentially arranged elements or vanes 7 which direct air flow from manifold 6 toward turbine wheel 3. The outer circumference of turbine wheel 3 supports an array of axial turbine elements 8 evenly distributed around the circumference of the turbine wheel. Two concentric rings of radial turbine elements 9, 10 are formed on a face 11 of wheel 3 remote from the inlet stator 4. The second stator 5 is provided with circular arrays of elements or vanes 12, 13 which respectively fit between axial elements 8 and 9 and radial elements 9 and 10. An exhaust manifold 14 is provide in housing 2.

Stators 4 and 5 support turbine wheel 3, for rotation about its axis. The turbine 3 is supported by the interengaging formations and does not require the use of supporting bearings. This is made possible by the above configuration in which the turbine wheel 3 is similarly loaded in opposing axial directions by the drive air pressure thus avoiding any WO 99/22117 PCT/AU98/00890 -4axially longitudinal loading. In this regard the inlet air directed through element 7 of stator 4 exerts a net force to the right as viewed in Figure 1 whilst the longitudinal loading by virtue of the air directed through elements 9, 13 and 10 is to the left as viewed in Figure 1.

Arrows 15 show the path of the air through the air turbine motor. In use, the air is admitted to manifold 6 by an appropriate control valve (not shown) in the known manner.

The air passes through elements 7 of stator 4 which direct the air generally axially into axially driven elements 8. The air exiting elements 8 is turned through 900 by elements 12 of stator to become a radially directed flow into the radially driven elements 9. The air exiting elements 9 is directed into the second stage of radially driven elements 10 (or third stage of the motor) by elements 13 of stator 5. The air then passes into exhaust manifold 14 for exhaust to the atmosphere in the usual manner.

The foregoing describes only one embodiment of the invention and modifications can be made without departing from the scope of the invention.

Claims

1. An air turbine motor including a turbine wheel mounted for rotation about an axis, a first set of elements displaced substantially around a circumferential outer edge of said turbine wheel and arranged to drive said turbine wheel in rotation about said axis in a first direction substantially only in response to an axial flow of air, a second set of elements displaced around said turbine radially inward from said first elements and arranged to drive said turbine wheel in rotation about said axis in said first direction substantially only in response to a radially inward flow of air and means to direct drive air to said first set of elements in an axially directed flow and stator means interposed between said first set of elements and said second set of elements to direct drive air emerging from said first set of elements to said second set of elements in a radially directed flow. ••go

2 An air turbine motor as claimed in claim 1 wherein said second set of elements is arranged on a face of said turbine wheel. *o °ig

3. An air turbine motor as claimed in claim 2 wherein said second set of elements is arranged in two consecutive stages whereby the drive air passes through one stage and then the other stage.

4. An air turbine motor as claimed in claim 3 wherein said two consecutive stages are formed by arranging the elements in two concentric circular arrays.

An air turbine motor as claimed in any one of claims 1 to 4 wherein said turbine wheel is mounted between two stators.

6. An air turbine motor as claimed in claim 5 wherein a first stator directs drive air axially toward said first set of elements and a second stator re-directs air emerging from the first set of elements to said second set of elements in a radial \,direction. P:\OPER\LKA\22862X spci.d.c-0211 1/1)1 -6-

7. An air turbine motor substantially as herein described with reference to the accompanying drawings.

DATED this 2nd day of November, 2001. 0* 9 9 499999 9 9 9 *999 9*9**9 0 9 9 9*

9. 9 9 99*9 Kenneth Douglas Horner by DAVIES COLLISON CAVE Patent Attorneys for the Applicant