Note: Descriptions are shown in the official language in which they were submitted.
APPARATUS FOR Cl,EANING JET ENGIME NOZZLES
BACKGROUND OF THE INVENTION
This application is a division of Canadian Serial
No. 309,224, filed August 14, 197~.
It has been the usual practice during overhaul to xemove
the fuel nozzles and guide vanes from the jet engines of an
aircraft, and to soak the parts in an appropriate solution so
as to remove the residue fuel varnish and carbon Erom the
surfaces thereof. However, such a procedure is time consuming
and costly.
The apparatus and process of the present invention
serves to cause a high pressure spray of water and detergent
solution to be emitted from the fuel nozzles of the jet
- engine with the nozzles and guide vanes in place in the engine,
in order to clean the nozzles and guide vanes thoroughly with-
out the need to dismantle the same from the engine.
As mentioned above, the apparatus to be described may
conveniencly be mounted in a vehicle to be transported to the
work site. A feature of the apparatus in the embodiment to be
20 described is that it incorporates pneumatic logic modules which ~ -
operate compIetely without electricity so as to be operable ~`
in any atmosphere without any danger of explosion and thereby
to be safe for hangar use.
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Thus, the invention can be defined as an apparatus for
cleaning residue fuel varnish and carbon from the fuel nozzles
` and guide vanes of a jet engine which includes an inlet for
- receiving compressed air, an outlet configured to be coupled . ::
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into the fuel system of a jet engine so that the fluid emitted
by the outlet may be discharged through the fuel nozzles of
the jet engine to perform a cleaning function, and pneumatically
operated control means for causing a pressurized stream of a
cleaning solution to be emitted through the outlet.
In a further embodiment the aforesaid pneumatically
controlled control means includes automatic sequencing timer
means for causing a first stream of cleaning solution to be
emitted through the outlet at relatively low pressure and for
a predetermined time interval for wetting purposes, and for
subsequently causing a second stream of cleaning solution to be
emitted through the outlet at relatively high pressure and as
intermittent bursts.
In a Eurther embodiment, the invention contemplates an
apparatu~ for cleaning residue fuel varnish and carbon from
the fuel nozzles and guide vanes of a jet engine, which includes
an inlet for receiving compressed air, an outlet configured
to be coupled into the fuel system of a jet engine so that
fluid emitted by the outlet may be discharged through the
fuel nozzles of the jet engine to perform a cleaning function,
and air reseiver means. A first compressed air operated pump
means is coupled to the inlet for introducing compressed air
into the air receiver means so as to achieve a predetermined
air pressure in the air receiver means, and a first liquid
accumulator means is coupled to the air receiver means. A reser-
voir is provided for a cleaning solution, and a second compressed
air operated pump means is coupled to the inlet and to the
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reservoir and to the first liquid accumulator means for intro-
ducing cleaning solution from the reservoir into the first
liquid accumulator means against the pressure of compressed
air from the air receiver means. A first conduit means couples
the first liquid accumulator to the outlet, and a first valve
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is included in the first conduit means. A control means coupled
to the first valve controls the flow of the cleaning solution
through the fixst conduit means from the first liquid accumu-
lator means to the outlet.
The invention also contemplates a process for cleaning
- the fuel nozzles and guide vanes of jet engines which comprises
disconnecting the fuel system of the engine from the fuel
nozzles. A first step initially introduces a pressurized stream
of cleaning solution at relatively low pressure into the fuel
nozzles for wetting purposes, and a second step after a pre-
determined time interval subsequently introduces the stream of
cleaning solution at relatively high pressure into the fuel
no~zles to be emitted through the fuel nozzles.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURES lA and lB are pictorial representations of
apparatus constructed in accordance with the invention; and
FIGURE 2 is a schematic functional diagram o the
apparatus.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
As shown in FIGURES lA and lB, the apparatus of the
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invention may be mounted on a three-wheeled cart 10 which may
be towed to the work site by a handle 12.
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In the schematic diagram of FIGU~E 2 f compressed air of
a pressure, for example, of 100 psi is in~roduced through an inlet
"I", and through a 3-way air supply valve 23 and 10 micron air fil~ ~`
ter 24, and through a pressure regulator 27A and lubricator 28A to
an air operated pneumatic booster pump 20, the pump being equipped
; with an appropriate air muffler 20A. Valve 23 has an "on" position
in which compressed air is supplied to the booster pump 20; a
"mix" position illustrated in FIGURE 2; and an-"off" position.
sooster pump 20 is coupled through a check vaIve 15B to an air
receiver 30, and is coupled back ~hrough a check valve 15A to the
inlet of regulator 27A. The outlet of filter 24 is.also coupled
through a pressure regulator 25, and through a three-way valve 29
and air filter 26 to a series of pneumatic sequencing timers 34,
35 and 36, the timer 34 being normally open, and the timers 35 and
36 being normally closed.
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Timer 34 may be set to close within a time range, for
example, of 1.5-15 seconds; the timer 35 may be set to open within
a time range of 3-30 minutes, for example; and the timer 36 may
be set to open within a time range of 5-50 seconds, for example.
The output of timer 34 is coupled to a pneumatic control
valve 38D, and the output of timer 36 is coupled to pneumatic contro
valves 38E and 38F. The output of timer 35 is coupled through a
normally open portion of control valve 38E to a pneumatic control
valve 38B and to a further pneumatic control valve 40. The output o
air filter 26 is also passed through a normally ciosed portion of
pneum~tic control valve 38D to a pneumatic control valve 38A.
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The output of booster pump 20 is introduced through check
valve 15B to the air receiver 30, whose internal pressure is desig-
nated by a gage 46. Air receiver 30 is coupled through a pressure
regulator 45 to a relatively small piston-type accumulator 32 whose
capacit~, for example, may be one gallon; and directly to a rela-
tively large piston-type accumulator 41 whose capacity for example,
may be five gallons. A relief valve 17 is provided in the line
between the air receiver 30 and piston accumulator 32.
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The pressure regulator 45 reduces the pressure intxo-
]0 duced to accumulator 32 from the air receiver 30 to a relatively lo~
value, so that a detergent solution is emitted from the accumula-
tor 32 at relatively low pressure; whereas the air receiver is
directly coupled to the accumulator 41 so that a solution dis-
charged from the accumulator 41 is at relatively high pressure.
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The output of air filter 24 is also passed through a check
valve 51A and a pressure regulator 27B and through a lubricator 28B
to an air-operated liquid pump 14, and through a check valve 51B
and receiver 54 to the normally closed pneumatic control valve 38C.
Pump 14 is equipped with a muffler 14A. Receiver 54 is included to
insure adequate pressure to operate actuator 50A when the apparatus
` is operated on marginal air supply systems. When valve 38C is
opened, the air pressure fxom recei~er 54 passes ~o the actuator
50A which controls a spring-loaded normally closed valve l9C. When
valve l9C is opened, pressurized air from accumulator 41 and air
25 receiver 30 is discharged to an outlet O through check valve 15E.
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A reservoir 2 for a water and de~ergent solution is pro-
vided in the apparatus, and is coupled through a 25 micron filter -~
31 and through a check valve 15C to pump 14. Pump 14 pumps the
detergent through a check valve 15D into accumulator 32, and through
an additional check valve 15F into accumula~or 41. Accumulator 32
; discharges its contents through a spring-loaded normally closed ball
valve l9A to outlet O; and accumulator 41 discharges its contents
through a spring-loaded normally closed ball valve l9B and through
a motor-operated ball valve l9D to outlet O. Outlet O is coupled
to an appropriate hose 47 which is equipped with a fitting 16 and
two short hoses 52 and 53.
In the operation of the apparatus, the fuel system is
interrupted and the hoses 52 and 53 are attached to tne fuel system, ~ ;
so that the detergent solution may be discharged through the
15 nozzles to perform the desired cleaning function. The jet engine
usually includes primary and secondary fuel injection systems.
, Hoses 52 and 53 provide connections to both systems. The hoses
provide flexibility for connection to the rigid fuel lines of`the
` engine.
A by-pass circuit for pump 14 through a shut-off valve 50
is provided, as well as an independent driving air supply for the
~ pump through valve 23 in its "mix" position (illustrated in FIGURE
; 2). This provides a mixing circuit for the detergent in reservoir 2
which has a tendency to separate out of solution if left standing
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25 for any length of time. To initiate a "mix" cyole/ it is merely
; necessary to turn valve 23 to its illustrated "mix" position and
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- open valve 50. Driving air is now supplied to the l~quid pump 14
only, and the solution is circulated through reservoir 2. ~.
The output of air filter 24 is also introduced ~hrough a
check valve 51A, through a lubricator 28C, and through the normally
closed control valve 38A to an actuator 50C which operates ~alve
~: l9A. When valve 38A is opened, the actuator 50C is caused to open
the valve l9A and discharge the contents of accumulator 32 through
outlet O. The output from the air filter 24 is also introduced
through the normally closed control valve 38B to an actuator 50B
which operates the spring-loaded valve l9B. When the control valve
38B is opened, the valve l9B is opened. The pressurized air from
the air filter 24 is also applied to the normally closed control
valve 40, and when the valve 40 is operated, an air motor 18 is
actuated which causes the valve l9D to rotate, intermittently to
open and close. When valve 19B is opened, and when motor 18 is
activated, intermittent bursts of t~he contents of accumulator 41 ar
introduced to outlet O.
To operate the system of FIGURE 2, the air supply valve
23 is opened, causing the booster pump 20 to operate and pump air
into the air receiver 30, until an air pressure in the air receive
of, for example, 500 psi is indicated by gage 46. At the same tim~
; ! the pump 14 pumps the detergent solution from reservoir 2 into the
accumulators 32 and 41, until both accumulators are filled with
the detergent solution.
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When the gage 46 indicates an air pressure of 500 psi in
the air receiver 30, for example, the valve 29 is opened to start
the sequence of operations in the system. When the valve 29 is opene
the pressurized air from air filter 26 passes through the timer 34
to the control valve 28D ~o operate the control valve 38D. This
causes the pressurized air to flow through the control valve 38D to
operate the control valve 38A. When control valve 38A is operated,
it causes actuator 50C to open valve l9A. The air pressure from
receiver 30 now forces the piston in accumulator 32 downwardly to
` 10 cause the detergent solution within the accumulator 32 to be dis-
charged through valve l9A, and through the outlet O of the system
to the fuel nozzle of the jet engine. This initial discharge of
about one gallon of the detergent solution is under low pressure,
and it serves to wet the surfaces of the nozzle and guide vanes of
:~ iJ~ the jet engine.
After a selected time interval established by the setting
of timer 34, (e.gO 1.5-15 seconds~ the timer 34 closes, and the
control valve 38D returns to its normally closed position, causing
control valve 38A to turn of~ valve l9A to terminate the discharge
of low pressure detergent from accumulator 32. After a preset time
interval ~e.g. 3-30 minutes) during which p~Tlp 14 and booster 20
recharge, timer 35 opens. The pressurized air from timer 35 flows
th~ough valve 38E to operate valves 38E and 40, so that the latter
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control valves are opened. The opening of valve 38B causesactuator 50B to open valve 19B, and the opening of valve 40 causes
air motor 18 to open and close valve l9D. The contents of the
accumulator 41 are then forced through valves l9B and l9D to be
emitted as pulsations of detergent solution under high pressure
from the outlet O, and subsequently through the nozzles of the jet
engine being cleaned. The flow rate in a constructed e~bodiment,
for example, is 25 gallons per minute.
The timer 36 times out ater a preset time, in the range
for example, of 5-50 seconds. When that occurs, the timer 36 causes
the control valve 38E to close, and causes control valve 38F to
: open~ When control valve 38E closes, both valves 38B and 40 close
to terminate the intermittent flow of detergent to outlet O. When
control valve 38F opens, valve 38C is opened to cause actuator 50A
to open valve l9C~ The opening of valve l9C by actuator 50A
causes pressurized air to flow from accumulator 41 and air receiver
~ 30 through check valve 15E, and through outlet O to the nozzle of
;; the jet engine to air dry the surfaces of the jet engine wetted
by the detergent emission from the apparatus~ Valve 29 must be
actuated to terrninate venting of air receiver 30 and accumulator
41 when pressure indicated on gage 46 is approximately lOQ psi~
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Valve 29 is a three-way val~e, and it is now turned to its second
position to interrupt the introduction of pressurized air to the
control system, and to vent and reset the timers 34, 35 and 36.
The air receiver 30 now re-charges, and the cycle may be repeated
S after the predetermined pressure is indicated by gage 46, by again
turning valve 29. ~;
The operation of the apparatus, as described in ~IGURE 2
therefore, first causes a small amount of detergent solution to
be emitted by the nozzle of ~he jet engine for cleaning purposes.
Then, under the automatic control of the system of FIGURE ~, pul-
; sating jets of the detergent solution are emitted at high pressure
through the fuel nozzle of the jet engine thoroughly to clean the
nozzle and the guide vanes of residue fuel varnish and carbon de-
posits~ After a predetermined time, the pulsating jets of the
detergent solution are terminated, and a stream of pressurized air
is emitted through the nozzle to dry the wetted surfaces of the
nozzle and of the guide vanes of the engine.
The invention provides, therefore, a relatively simple
apparatus and process which automatically enables the nozzles and :~:
I guide vanes of jet engines to be thoroughly cleaned, without any ~:~
need for dismantling the same, and in a simple and expeditious
manner. As mentioned ahove, the apparatus of the invention, in
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the embodiment described above, is advantageous in that it is com-
pletely pneumatic in its operation, so as to be capable of use in
aircraft hangars without any danger of creating fires or explosions
It will be appreciated that while a particular embodiment
of the invention has been shown and described, modifications may
;~ be made. It is intended in the accompanying claims to cover all
the modifications which come within the spirit and scope of the
invention.
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