Air turbine starter with seal assembly

Details Air turbine starter with seal assembly Air turbine starter with seal assembly

1999-08-09

2001-11-20

Verdier, Christopher (Department: 3745)

Rotary kinetic fluid motors or pumps

With lubricating, sealing, packing or bearing means having...

For shaft sealing, packing, lubricating or bearing means

C415S111000, C415S113000, C415S122100, C415S230000, C415S231000

Reexamination Certificate

active

06318958

ABSTRACT:

TECHNICAL FIELD
This invention relates generally to air turbine starters and in particular to seals used in such starters.
BACKGROUND OF THE INVENTION
Referring to the drawings,
FIG. 2
shows a prior art turbine face seal commonly used in air turbine starters. The face seal includes a rotor
2
mounted to shaft
24
adjacent a bearing
26
. The rotor
2
has an axially facing flange
3
. The face seal further includes a stator
4
mounted to turbine exhaust housing
27
. Disposed between the rotor
2
and the stator
4
is a carbon seal ring
5
that sealingly engages the flange
3
.
In typical air turbine starters such the ATS 100 shown in
FIG. 1
, the rotation of the turbine wheel
22
can generate under certain circumstances a low pressure or “vacuum” on the downstream side of the wheel which is also the airside of the turbine seal. This differential pressure results in large oil leakage rates if the turbine seal has any flaws or coke build up in the contact zone. The coke build-up destroys the flatness of the sealing contact surfaces between the rotor and the seal carbon ring. The coke separates the two surfaces resulting in a clearance therebetween. As a result an air/oil mist is pulled from the bearings through the seal and into the turbine exhaust air. If 100 to 300 ccs of oil is displaced to the turbine exhaust air without detection by the pilot or ground crew, loss of the air turbine starter by turbine bearing failure is possible. This sensitivity of the system design to turbine seal flaws results in the turbine seal being in the top three causes of air turbine starter returns from the field for cause.
Accordingly, there is a need for a turbine seal for use in air turbine starters that prevents oil leakage even in the presence of a coke build up.
SUMMARY OF THE INVENTION
An object of the present invention is to provide for a turbine seal for use in air turbine starters that prevents oil leakage even in the presence of coke build up.
The present invention achieves this object by providing an air turbine starter with an improved seal assembly disposed between the turbine and the housing. The seal assembly comprises a face seal, a non-contacting seal axially spaced therefrom to define an air filled annular chamber therebetween and a flow passage having an exit fluidly communicating with said chamber and an inlet fluidly communicating with a source of air.
The air filled chamber acts as a buffer separating the differential pressure generated by pumping of the turbine from the face seal. Thus if the face seal develops a flaw (due to coke build up on the contact face or grain pull out from the carbon face) the seal leakage is low even if the sealing faces separate.
These and other objects, features and advantages of the present invention, are specifically set forth in, or will become apparent from, the following detailed description of a preferred embodiment of the invention when read in conjunction with the accompanying drawings.


REFERENCES:
patent: 1773067 (1930-08-01), Ver Planck
patent: 1878731 (1932-09-01), Thompson
patent: 2907595 (1959-10-01), Benson et al.
patent: 3235269 (1966-02-01), Olesen
patent: 3302951 (1967-02-01), Olesen
patent: 3796507 (1974-03-01), Smykal et al.
patent: 3799559 (1974-03-01), Kayser
patent: 3904211 (1975-09-01), Dega
patent: 3989407 (1976-11-01), Cunningham
patent: 4099727 (1978-07-01), Weiler
patent: 4156342 (1979-05-01), Korta et al.
patent: 4189156 (1980-02-01), Geary, Jr. et al.
patent: 4193603 (1980-03-01), Sood
patent: 4257617 (1981-03-01), Hill
patent: 4997340 (1991-03-01), Zinsmeyer et al.
patent: 5003767 (1991-04-01), Rodgers
patent: 5042963 (1991-08-01), Sorensen et al.
patent: 5129782 (1992-07-01), Ruetz
patent: 5160005 (1992-11-01), Burch
patent: 5412977 (1995-05-01), Schmohl et al.
patent: 5454689 (1995-10-01), Falavigna
patent: 5489190 (1996-02-01), Sullivan
patent: 5538258 (1996-07-01), Hager et al.
patent: 5619850 (1997-04-01), Palmer et al.
patent: 5692756 (1997-12-01), Altieri
patent: 651921-A (1951-04-01), None
patent: 59-117957-A (1984-07-01), None

Affiliated with

Also associated with

Rating

Air turbine starter with seal assembly does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Air turbine starter with seal assembly, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Air turbine starter with seal assembly will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2590042