Information
-
Patent Grant
-
6712080
-
Patent Number
6,712,080
-
Date Filed
Friday, February 15, 200222 years ago
-
Date Issued
Tuesday, March 30, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 134 941
- 134 951
- 134 971
- 134 991
- 134 992
- 134 1031
- 134 105
- 134 111
- 134 166 R
- 134 116
- 134 169 R
- 134 169 A
- 134 113
-
International Classifications
-
Abstract
A flushing system for flushing away any coking material which may have built up in the bearing of a gas turbine. Three fluid tanks respectively contain a solvent for dissolving the coked material, a cleaner and a lubricant. By means of a three-way valve, one of the fluids is provided to a supply pump for delivery to the bearing housing via a quick disconnect coupling. Fluid is returned to the appropriate tank by means of a return pump, via a quick disconnect coupling and another three-way valve between the return pump and the tanks. The system includes respective filters for filtering the return fluids and the entire system may be carried on a wheeled cart for servicing the gas turbine.
Description
STATEMENT OF GOVERNMENT INTEREST
The invention described herein may be manufactured and used by or for the Government of the United States of America for government purposes without the payment of any royalties therefor.
BACKGROUND OF THE INVENTION
Gas turbines, including those used for propelling military vehicles, include two or more opposed bearings which must be continuously lubricated during gas turbine usage. This is accomplished by means of a lubricating system which provides the bearings with a lubricating fluid, such as natural or synthetic oil, to not only lubricate the bearings but to also provide for cooling.
When the gas turbine is shut down after usage, the residual heat from the turbine (which may be hundreds of degrees Fahrenheit) soaks back to the bearings leading to a possible coking condition. This is even more pronounced if there is insufficient engine idle time before turbine shut down. Basically, coking is the result of the lubricant becoming an oxidized solid oil deposit on the bearing surface and in the lubricant delivery system that can lead to insufficient lubricant supply to the bearings. This can result in engine seizure and/or a requirement for a complete engine overhaul, which is undesirable, particularly in tactical combat situations.
Accordingly, it is a primary object of the present invention to provide apparatus which flushes away the coked lubricant in rotating machinery bearings, particularly, in gas turbines which shut down at high temperatures.
SUMMARY OF THE INVENTION
A flushing system for removing lubricant coking in a turbine bearing, within a bearing housing having a fluid inlet and fluid outlet, includes a plurality of fluid containing tanks, at least a first of which contains a coking solvent, a second of which contains a cleaner and a third of which contains a lubricant. First and second couplings are provided with a first coupling being connected to the fluid inlet and the second coupling being connected to the fluid outlet, of the bearing housing. A supply pump has an outlet connected to the first coupling, and a return pump has an inlet connected to the second coupling. A first valving arrangement is connected between the tanks, and an inlet of the supply pump, and is operable to provide fluid from a selected one of the tanks to the supply pump for delivery to the bearing housing. A second valving arrangement is connected between an outlet of the return pump and the tanks, to supply return fluid from the bearing housing to the particular tank selected by the first valving arrangement.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood, and further objects, features and advantages thereof will become more apparent from the following description of the preferred embodiment, taken in conjunction with the accompanying drawings, in which:
FIG. 1
is a simplified block diagram of a gas turbine and lubricating system.
FIG. 2
is a block diagram of the flushing system of the present invention, attached to a bearing as in FIG.
1
.
FIG. 3
is a more detailed presentation of the flushing system of FIG.
2
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the drawings, which are not necessarily to scale, like or corresponding parts are denoted by like or corresponding reference numerals.
In
FIG. 1
, a rotating gas turbine
10
is supported by opposed first and second bearings
12
and
14
, although, more such bearings may be utilized, depending upon turbine size and design.
A lubricating system
16
is provided in order to supply the bearings with necessary lubrication and cooling during use, and when the gas turbine
10
shuts down, the lubrication system
16
also shuts down, leading to a possible coking condition, as previously explained. The present invention obviates this problem by flushing away any coked deposits, and to this end, reference is made to FIG.
2
.
In
FIG. 2
, the lubricating system
16
is illustrated as being connected to a representative bearing housing
20
for delivering lubricating fluid to the bearing, via a one-way valve
22
and fluid inlet
24
, and for receiving used lubricant from the bearing, via fluid outlet
26
and one-way valve
28
. Flushing system
30
is connectable with the bearing housing inlet
24
by means of coupling
32
and is connectable with the bearing housing outlet
26
by means of coupling
34
.
The flushing system
30
may be a permanent installation in a maintenance facility, or, may be a portable system in which a system carrier is wheeled up to the gas turbine-driven vehicle. To facilitate rapid servicing, the couplings
32
and
34
are preferably of the threadless quick-disconnect type which have respective male connectors
32
m
and
34
m
, which mate with respective female connectors
32
f
and
34
f
. When uncoupled, the female connectors
32
f
and
34
f
prevent fluid from exiting the connector. The portable system also includes respective flexible hoses
36
and
38
, which may be wound up upon the carrier.
A more detailed view of the flushing system
30
is presented in FIG.
3
. After the gas turbine on the vehicle has shut down, the flushing system
30
is wheeled up to the vehicle and is connected to the bearing inlet
24
and outlet
26
by unwinding the flexible hoses
36
and
38
and by bringing together the respective connectors of couplings
32
and
34
.
The flushing system
30
includes a plurality of fluid holding tanks
40
-
42
, a first of which contains a solvent for dissolving any coked oil. By way of example the solvent may be a 50-50 solution of tetrahydrofuran and cyclohexane which turns the coked lubricant into a fine powder. A second tank,
41
, contains a cleaner, such as alcohol or kerosene, to remove any solvent and dissolved coke material. A third tank,
42
, contains lubricant to re-lubricate the bearings.
By a valving arrangement, the liquids in the tanks
40
-
42
are selectively provided to the bearing housing
20
via coupling
32
, by means of a supply pump
44
, having an inlet
45
and outlet
46
, and liquid is withdrawn from the bearing housing
20
by means of a scavenge, or return pump,
47
, having an inlet
48
and outlet
49
. More particularly, the valving arrangement includes a first three-way valve
50
which is automatically, or hand operated, to selectively connect supply pump
44
with either solvent tank
40
, cleaner tank
41
or lubricant tank
42
. A similar three-way valve
52
is operative to selectively direct return fluid from return pump
47
, to either solvent tank
40
, cleaner tank
41
or lubricant tank
42
.
Prior to entering the return pump
47
, return fluid from the bearing is preferably filtered. This is accomplished with the provision of a filter station
56
comprised of three filters
58
-
60
, one for each of the tanks
40
-
42
, and selectively put into the fluid circuit by means of three-way valves
62
and
64
. These valves
62
and
64
are operated to direct fluid: A) to filter
58
when solvent from solvent tank
40
is being supplied, B) to filter
59
when cleaner from cleaner tank
41
is being supplied, and C) to filter
60
when lubricant from lubricant tank
42
is being supplied.
In operation, after coupling with the bearing housing
20
, the pumps
44
and
47
of the flushing system
30
are turned on such that, initially, solvent from tank
40
is provided to the bearing with the proper positioning of three-way valves
50
,
52
,
62
and
64
. The solvent is continuously supplied to the bearing for a period of time in order to dissolve the coked material. In order to assist in determining this period of time, a flowmeter
66
is provided in the fluid line from supply pump
44
to the bearing housing
20
. Based upon an increased flow rate of the solvent, as determined by the flowmeter
66
, the valving arrangement may be changed so as to next provide cleaner from tank
41
to remove the solvent from the bearing housing
20
. After another predetermined period of time, the three-way valves are positioned to supply lubricant from tank
42
for a few minutes, to replenish the bearing housing
20
with fresh lubricant prior to a subsequent start-up of the gas turbine.
In order to further monitor the system during the flushing operation, the system also includes a pressure gage
68
and a thermocouple
70
, both of which are connected to the fluid circuit downstream of the supply pump
44
. Additionally, if the pressure in the fluid line exceeds a certain value, a relief valve
72
is operative to direct the fluid from pump
44
back to three-way valve
52
via fluid line
74
. After the complete flushing operation, couplings
32
and
34
are disconnected and the gas turbine-driven vehicle may return to its assigned task.
As mentioned, the flushing system
30
may be completely portable for delivering the system to a gas turbine-driven vehicle for servicing. Accordingly, the components of the flushing system
30
may be carried on a wheeled cart, generally represented by the numeral
76
, in FIG.
3
.
It will be readily seen by one of ordinary skill in the art that the present invention fulfills the primary object set forth herein. After reading the foregoing specification, one of ordinary skill in the art will be able to effect various changes, substitutions of equivalents and various other aspects of the present invention as broadly disclosed herein. It is therefore intended that the protection granted hereon be limited only by the definition contained in the appended claims and equivalents. Having thus shown and described what is at present considered to be the preferred embodiment of the present invention, it should be noted that the same has been made by way of illustration and not limitation. Accordingly, all modifications, alterations and changes coming within the spirit and scope of the present invention are herein meant to be included.
Claims
- 1. A flushing system for removing lubricant coking in a turbine bearing, within a bearing housing having a fluid inlet and fluid outlet, comprising:a plurality of fluid containing tanks, at least a first of which contains a coking solvent, a second of which contains a cleaner and a third of which contains a lubricant; first and second couplings, said first coupling being connected to said fluid inlet and said second coupling being connected to said fluid outlet, of said bearing housing; a supply pump having an inlet, and having an outlet connected to said first coupling; a return pump having an outlet, and having an inlet connected to said second coupling; a first valving arrangement connected between said plurality of tanks and said inlet of said supply pump and operable to provide fluid from a selected one of said tanks to said supply pump for delivery to said bearing housing; a second valving arrangement connected between said outlet of said return pump and said tanks to supply return fluid from said bearing housing to said tank selected by said first valving arrangement.
- 2. A system according to claim 1 wherein:said first valving arrangement is a three-way valve.
- 3. A system according to claim 1 wherein:said second valving arrangement is a three-way valve.
- 4. A system according to claim 1 wherein:said first and second couplings are threadless quick-disconnect couplings.
- 5. A system according to claim 1 which includes:at least three fluid filters each for filtering a respective one of said fluids returning to said tank selected by said first valving arrangement.
- 6. A system according to claim 5 wherein:said filters are positioned in the fluid line between said second coupling and said inlet of said return pump; and which includes third and fourth valving arrangements for placing a selected one of said filters into the fluid circuit.
- 7. A system according to claim 1 which includes:a flowmeter in the fluid circuit between said outlet of said supply pump and said first coupling.
- 8. A system according to claim 1 which includes:pressure and temperature sensors positioned for obtaining pressure and temperature readings of the fluid in the fluid circuit between said outlet of said supply pump and said first coupling.
- 9. A system according to claim 1 which includes:a fluid line connecting said outlet of said supply pump to said outlet of said return pump; and a relief valved positioned in said fluid line.
- 10. A system according to claim 1 wherein:said flushing system is carried on a wheeled cart.
- 11. A system according to claim 1 wherein:said turbine bearing is a gas turbine bearing.
US Referenced Citations (19)
Foreign Referenced Citations (1)
Number |
Date |
Country |
WO 9214557 |
Sep 1992 |
WO |
Non-Patent Literature Citations (1)
Entry |
WO 92/14557 Sep. 1992. |