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Claims  |
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What is claimed as new is:
1. In combination with a lavatory waste tank having a waste drain and a
fluid operated waste drain valve mounted in said tank to open and close
said drain and tank rinsing means in said tank for rinsing the interior of
said tank:
(a) flow measuring means adapted to be connected to a source of rinsing
fluid under pressure and for measuring at least first and second
predetermined volumes of said rinsing fluid flowing therethrough:
(b) controllable valve means coupled between said flow measuring means and
waste drain valve and tank rinsing means; and
(c) control means, responsive to said flow measuring means for operating,
during the period in which said first predetermined volume is measured,
said controllable valve means to receive said fluid under pressure from
said flow measuring means and deliver said rinsing fluid to the waste
drain valve to open said waste drain valve and to the rinsing means and
thence to the waste tank and, during a period in which said second
predetermined volume is measured, to receive said rinsing fluid under
pressure from said flow measuring means and deliver said rinsing fluid to
the rinsing means and thence to the waste tank; and prevent said rinsing
fluid from said flow measuring means from being delivered to said waste
drain valve to close said waste drain, whereby said rinsing fluid is
supplied through said waste tank for at least a first predetermined period
to rinse said tank, and is supplied to said waste tank for at least a
second predetermined period to fill the tank.
2. The combination of claim 1, above, wherein said controllable valve means
comprise first and second solenoid valves each adapted to be opened and
closed by said control means for delivering a predetermined quantity of
fluid to the waste drain valve and to the rinsing means, respectively.
3. The combination of claim 2, above, wherein said flow measuring means
provides electrical signals corresponding to and representative of the
volume of fluid flowing therethrough and further including:
electronic counting means adapted to receive said electrical signals for
generating control signals corresponding to and representative of
predetermined volumes of fluid flow; and
valve control means operatively connected to receive said control signals
an operable in response thereto to regulate delivery of fluid from said
first and second solenoid valves based upon said control signals.
4. The combination of claim 3, above, further including rechargeable
electrical power supply means adapted to provide electrical power to said
flow measuring means, said first and second solenoid valves, said
electronic counting means and said valve control means, said electrical
power supply means including charging means for recharging said electrical
power supply means while the combination is quiescent.
5. The combination of claim 1, above, wherein:
(a) said flow measuring means are adapted to provide rotational motion to
said control means; and
(b) said control means are operable in response to rotational motion for
selectively operating said controllable valve means.
6. The combination of claim 5, above, wherein said controllable valve means
comprises:
(a) control valve cylinder means having fluid flow orifices in the walls
thereof;
(b) timing gear reduction means coupled to said flow measuring means for
receiving rotational motion from said flow measuring means and responsive
thereto to impart rotational motion to said control valve cylinder means;
(c) pressure responsive clutch means connected to said control valve
cylinder means and operable in response to fluid under pressure flowing
through said control valve cylinder means for engaging said timing gear
reduction means with said control valve cylinder means;
(d) control valve piston means, coupled to said control valve cylinder
means for imparting linear motion, in response to applied fluid pressure,
to engage said clutch means thereby;
(e) first bias means for providing a force resistive to said fluid
pressure, for restoring said control valve cylinder means to an initial
linear position upon the cessation of applied fluid pressure; and
(f) second bias means coupled to said control valve cylinder means for
providing a force opposing applied rotational motion, thereby restoring
said control valve cylinder means to an initial rotational position upon
disengagement of said clutch means, decoupling said control valve cylinder
means from said timing gear reduction means.
7. The combination of claim 5, above, wherein said control means comprise:
(a) transmission means providing a source of rotational motion to said
control valve cylinder means from said flow measuring means, corresponding
to and representative of fluid flow volume.
8. The combination of claim 7, above, wherein said transmission means
comprises:
(a) timing gear reduction means;
(b) pressure responsive clutch means connected to said controllable valve
means and operable in response to fluid under pressure flowing through
said controllable valve means for coupling said timing gear reduction
means to said controllable valve means; and
(c) controllable valve return means coupled to said controllable valve
means for placing said controllable valve means in an initial
configuration when said clutch means decouples said timing gear reduction
means from said controllable valve means.
9. The combination of claim 7, above, wherein said transmission means
comprises:
(a) a preprogrammed control cam, adapted to be rotated by said transmission
means through an operating cycle.
10. The combination of claim 1, above, wherein said flow measuring means
provides an electrical signal corresponding to and representative of the
volume of fluid flowing through said flow measuring means and said control
means are adapted to receive said electrical signals from said flow
measuring means for regulating the delivery of fluid from said
controllable valve means to the waste drain valve and rinsing means, based
upon said electrical signals.
11. The combination of claim 10, above, wherein said control means
comprises:
(a) electronic counting means adapted to receive said electrical signals
for generating control signals corresponding to and representative of
predetermined volumes of fluid flow; and
(b) valve control means, operatively connected to receive said control
signals and responsive thereto to regulate delivery of fluid from said
controllable valve means to the waste drain valve and rinsing means, based
upon said control signals.
12. The combination of claim 10, above, further including electrical power
supply means adapted to provide electrical power to said flow measuring
means and said control means, wherein said power supply means includes
charging means for recharging said power supply means while the
combination is quiescent.
13. In combination with a lavatory waste tank having a waste drain and a
fluid operated waste drain valve mounted in said tank to open and close
said drain and means for rinsing the interior of said tank;
(a) flow measuring means adapted to be connected to a source of rinsing
fluid under pressure and to measure at least first and second
predetermined volumes of said rinsing fluid flowing therethrough;
(b) first and second valve means coupled between said flow measuring means
and waste drain valve and tank rinsing means to receive said rinsing fluid
under pressure from said flow measuring means;
(c) transmission means adapted to receive rotational motion from said flow
measuring means and to actuate said first and second valve means in
response to said at least first and second predetermined volumes, whereby
during the period in which said first predetermined volume is measured,
said first valve means delivers said rinsing fluid to the waste drain
valve and thence to the rinsing means and waste tank and, during the
period in which said second predetermined volume is measured said second
valve means delivers said rinsing fluid to the rinsing means the thence to
the waste tank; and prevent said rinsing fluid from said flow measuring
means form being delivered to said waste drain valve to close said waste
drain; whereby said rinsing fluid is supplied through said waste tank for
at least a first predetermined period to rinse said tank, and is supplied
to said waste tank for at least a second predetermined period to fill the
tank.
14. The combination of claim 13, wherein said transmission means further
comprises:
(a) timing gear reduction means;
(b) pressure responsive clutch means connected to said first and second
valve means and operable in response to fluid under pressure flow through
said valve means for coupling said timing gear reduction means to actuate
said valve means;
(c) valve return means coupled to said first and second valve means for
placing said valve means in an initial configuration when said clutch
means decouples said timing gear reduction means from said controllable
valve means.
15. The combination of claim 14, above, wherein said transmission means
further comprises:
(a) a preprogrammed control cam, adapted to be driven by said timing gear
reduction means through said clutch means, for driving said cam through an
operating cycle.
16. The combination of claim 13, above, wherein said first and second valve
means include control valve cylinder means having fluid flow orifices in
the walls thereof corresponding to first and second valves and coupled to
receive fluid under pressure from said flow measuring means for delivering
fluid through said first valve to the waste drain valve, and through said
second valve to the rinsing means; the combination further including:
timing gear reduction means coupled to said flow measuring means for
receiving rotational motion imparted therefrom and responsive thereto to
impart rotational motion;
pressure responsive clutch means connected to said control valve cylinder
means and operable in response to fluid under pressure flowing through
said control valve cylinder means for releasably coupling said timing gear
reduction means to said control valve cylinder means for transmitting
rotational motion therebetween;
control valve piston means coupled to said control valve cylinder means for
providing linear motion in response to applied fluid pressure to engage
said clutch means thereby;
first bias means providing a resistive force against said fluid pressure,
for disengaging said control valve cylinder means from said clutch means
upon the cessation of applied fluid pressure; and
second bias means for providing a force opposing rotational motion for
restoring said cylinder means to an initial rotational position upon
disengagement of said cylinder means from said clutch means;
whereby said timing gear reduction means rotates said control valve
cylinder through said clutch means to enable said first and second valves
in a predetermined sequence to apply fluid to the waste drain valve and to
the rinsing means.
17. In combination with a lavatory waste tank having a waste drain and a
fluid operated waste drain valve mounted in said tank to open and close
said drain and tank rinsing means in said tank for rinsing the interior of
said tank:
(a) volume measuring means adapted to generate signals corresponding to a
drained waste tank, and a rinse volume and a precharge volume of the
rinsing fluid levels in the waste tank;
(b) solenoid valve means coupled to receive rinsing fluid under pressure
and adapted to be opened and closed for delivering predetermined volumes
of said rinsing fluid to the waste drain valve and the rinsing means;
(d) valve control means operatively connected to receive signals from said
volume measuring means and operable in response thereto to regulate
selectively delivery of said rinsing fluid from said solenoid valve means
to the waste drain valve or to rinsing means, and thence to the waste
tank, based upon said control signals whereby during a first period, said
valve means delivers rinsing fluid to said waste drain valve until said
waste tank is drained, and, during a second period, said valve means
delivers rinsing fluid to said rinsing means until said waste tank
contains a rinse volume of rinsing fluid, and, during a third period, said
valve means delivers rinsing fluid to said waste drain valve until said
waste tank is drained, and, during a fourth period, said valve means
delivers rinsing fluid to said rinsing means until said waste tank
contains a precharged volume of said rinsing fluid.
18. The combination of claim 17 above, further including electrical power
supply means adapted to provide electrical power to said volume measuring
means, said solenoid valve means and said valve control means wherein said
power supply means includes charging means for recharging said power
supply means while the combination is quiescent. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to waste tank servicing assemblies and more
particularly to a combination of a flowmeter with a flow valve assembly
operating a fluid operated waste drain valve and spray/rinse apparatus
adapted to be installed in an aircraft lavatory waste tank.
2. Description of the Prior Art
In some aircraft lavatory systems currently in use, a common waste tank is
provided in conjunction with more than one lavatory unit. In others, a
tank is provided for each lavatory. During a flight, the waste tank, which
may be used with a recirculating toilet system or, alternatively, with a
fresh water system, is utilized to retain human wastes. At the conclusion
of a flight, the tank is drained and cleaned by ground service personnel.
During that process, the tank is rinsed out with a cleaning fluid which
may include deodorants and disinfectants, and is provided with a
predetermined quantity of precharge liquid (depending on the
installation), prior to the next flight of the aircraft.
In waste systems of the prior art, the tank drain valve is connected
through a cable assembly to a manual release mechanism which is located at
the service panel. As noted in U.S. Pat. No. 4,338,689, issued July 13,
1982, to Clifford V. Zieg and assigned to the assignee of the present
invention, alignment problems were encountered with a valve that was
manually operable through a cable. Prior art systems employed a long rigid
extension tube to assure continued alignment of the valve in the valve
seat. The patent to Zieg, however, illustrated a novel, elastomeric valve
plug which could accommodate some degree of misalignment and still form an
adequate seal for the tank.
The tanks of the prior art also included a special drain fitting or nipple
which was adapted to connect to a servicing vehicle. The vehicle supplied
a cleaning and rinsing fluid to an intake port which applied the fluid to
the interior of the tank through a spray system. After the drain valve was
seated, the same spray system was used to impart a premeasured precharge
to the tank, necessary for recirculating toilet systems.
In servicing a waste tank according to prior art, a technician would couple
a waste line to the nipple at the service panel. The technician would then
manually, through use of a cable into the coupled waste line. A cleaning
fluid line would then be connected to the intake port and a combination of
a cleaning and disinfecting fluid was applied through a spray line,
cleaning the interior of the tank while the drain valve was kept open.
After a predetermined time interval, usually after the prescribed volume of
fluid had been delivered, the drain valve would be closed by releasing the
cable. The tank was then filled to approximately 75% capacity by
permitting additional, rinsing/cleaning fluid to be supplied until the
predetermined quantity of fluid had been furnished. The technician would
then manually dump the tank contents again and finally fill the tank with
a precharged quantity. Tank trucks frequently are fitted with meters which
display the quantity of fluid that has been delivered.
The prior art system became a source of at least two major problems, even
with the modified drain plug of the Zieg invention. One problem was cable
breakage which required a partial disassembly of the tank and aircraft to
reinstall a new cable system. In addition, the various elements of the
cable system required service and maintenance and, because of the hostile
environment, from time to time would become inoperable, preventing the
operation of the drain valve.
A second, potentially more serious problem is the service technician, who,
either through inattention or carelessness, fails to shut off the
cleaning/rising supply after the specified volume has been furnished or
time interval has elapsed, resulting in an excessive precharge in the
tank. In some instances, this could impose a premature limit on the usage
of the lavatory, since, once the tank is determined to be full, further
usage is prohibited. Since this circumstance usually occurs during the
flight, those lavatories which are coupled to the tank must be taken out
of service.
A more serious consequence of technician inattention is the overflow of the
tank during servicing. Serious structural damage to the aircraft could
result since the cleaning/rinsing fluid tends to be highly corrosive to
metallic parts. Moreover, any overflow into the lavatory compartment or
into the inaccessible interior of the fuselage of the aircraft creates a
potential hazard to the integrity of the structural and control elements
of the aircraft.
U.S. Pat. No. 4,584,726, issued Apr. 29, 1986, to Grills, et al., and
assigned to the assignee of the present invention illustrated a waste
drain valve assembly that automatically opens upon the application of
cleaning/rinsing fluid and at the same time provides a predetermined
quantity of precharge fluid to the tank, specific to the type of aircraft
being serviced without any special attention required of the service
technician. The service technician merely attaches a line providing
cleaning and rinsing fluid to an intake line leading to the waste drain
valve assembly and shuts down the system after a prescribed time interval
has elapsed. A built-in precharge reservoir then supplies the proper
quantity of fluid as a precharge, after the valve has closed.
Although the improvements of the Grills, et al., invention eliminates the
possibility that the service technician will give the tank an excess
precharge, his attention is still required to insure that the fluid is
delivered to the waste drain valve assembly for the proper fluid quantity
or minimum time interval necessary to drain and rinse the tank.
Carelessness or inattentiveness of the service technician could result in
wasteful quantities of cleaning/rinsing fluid being run through the
system, since any quantities of fluid in excess of the amount required to
rinse would be emptied through the fluid operated drain valve.
What is needed, and what has been provided in the present invention, is a
system that measures the delivery of fluid to the waste drain valve and
automatically terminates the cleaning cycle upon delivery of a
predetermined quantity of fluid. The service technician need only hook up
the fluid supply line to the fluid intake line, turn on the fluid supply
and the system insures that the proper measure of fluid is delivered to
the waste tank, freeing the service technician to do other tasks.
3. Summary Of The Invention
In a preferred embodiment, an improved lavatory waste tank cleaning system
includes a flow meter which activates valves that provide fluid to a fluid
operated waste drain valve and to a rinsing and cleaning system. The flow
meter is coupled to the intake port and meters the delivery of fluid to
the system.
In the preferred embodiment, the flow meter operates the flow valves
through an electronic counter and solenoid valve system. The flow meter
delivers a train of electronic pulses to the electronic counter. The
electronic counter recognizes a predetermined pulse count and opens and
closes a pair of solenoid valves, in a predetermined sequence,
alternatively delivering fluid to the waste dump valve and the
cleaning/rinsing system, and to the waste tank. A rechargeable battery
power supply energizes the electronic system in the absence of other
sources of power. The battery is charged during flight. A pressure switch
may be included which suppresses the counter until a predetermined
pressure is reached in the line. The pressure switch can also function to
hold the valves closed at the completion of a cycle until the pressure
drops below the predetermined level.
In the preferred embodiment, the initial provision of fluid flow through
the first flow valve into the fluid operated waste drain valve operates
the drain valve, dumping the contents of the tank. As the valve is held
open, additional fluid is routed to a rinse-spray structure which cleans
the interior of the tank. After a predetermined volume of fluid flows
through the flow meter, the counter signals the closing of the first,
normally open solenoid flow valve.
One typical waste drain valve is disclosed in the recently issued U.S. Pat.
No. 4,584,726, to Grills et al., assigned to the assignee of the present
invention. The drain valve includes a hydraulic piston with a return
spring whose force can be overcome by fluid pressure. The flow from the
pressurized source of fluid, usually a service vehicle, thereby opens the
drain valve. The continued provision of cleaning/rinsing fluid to the
system through the normally open first flow valve maintains the drain
valve in the open position.
Fluid flowing through the first flow valve and piston chamber enters the
spray rinse system through a check valve. The continued provision of fluid
under pressure to the first flow valve thus provides for the simultaneous
cleaning, rinsing and draining of the waste tank.
When enough fluid has been supplied to the system for rinsing the waste
tank, the counter commands the energizing of the first solenoid flow
valve, closing it to further flow. The fluid pressure at the waste dump
valve is reduced, enabling the force of the return spring to overcome the
force of the fluid pressure, thereby allowing the waste drain or dump
valve to close.
A second, preprogrammed volume of fluid is now provided to the second flow
valve which delivers it directly into the waste tank through the spray
rinse system. The second flow valve remains open for a premeasured
quantity of fluid. The counter signals the second solenoid flow valve to
close after the proper quantity of fluid has been dispensed to the tank.
An optional signal lamp can be placed at the service panel to indicate to
the service operator that the cycle has been completed.
When the operator at the source of fluid recognizes that the cycle is
completed, he may cut off the fluid supply to the intake line and the flow
meter. Where a pressure switch is used, the valves are held closed until
the fluid supply is cut off. The first flow valve then opens in readiness
for the next cycle. The fluid already in the waste tank then serves as a
"precharge", which can prevent wastes from adhering to "dry" areas of the
tank and, more importantly, provides the necessary "precharge" or minimum
volume needed for operating a recirculating toilet system.
Because aircraft in a servicing area frequently lack an on board power
supply, in the preferred embodiment, the system has a built in power
supply which operates with a small rechargeable battery. The battery is
charged by the aircraft electrical power system during flight. In the
absence of other sources of power, the battery is sufficient to provide
power to the flowmeter, the electronic module and the solenoid valves
during the cleaning cycle.
In an alternative embodiment, a positive displacement flowmeter is driven
mechanically and operates the flow valves by rotating a programmed control
valve that delivers a predetermined volume of fluid to the waste drain
valve and the cleaning system. The control valve has fluid flow orifices
in its walls which are positioned to alternatively provide fluid to the
waste drain valve and the cleaning system, depending on the rotational
position of the control valve. The flowmeter thus rotates the control
valve through various stages of its cycle, depending on the volume of
fluid delivered to the flowmeter.
In other embodiments, the measurement of fluid is accomplished by liquid
level sensors that are positioned in the waste tank. A first sensor
indicates that the tank is empty, a second sensor could signal the
appropriate precharge level and a third sensor would signal that the tank
is at its fill limit. An additional sensor could signal an intermediate
fluid volume which could be used during the cleaning cycle to command
opening of the waste drain valve during the "rinse" portion of the cycle.
It is within the scope of the present invention to use alternative
configurations of apparatus and to measure the fluid usage differently.
For example, one alternative method of operation would utilize a timer and
impose a different sequence of actions. Since most tanks are provided with
one or more liquid level sensors, it is possible to apply fluid to the
first solenoid valve opening the hydraulically operated drain valve. After
a brief interval sufficient to drain the contents of the tank, the first
valve can be energized to close, thereby closing the drain valve, as well.
The second solenoid valve can then be energized, providing fluid to the
waste tank until an intermediate liquid level sensor signals a partially
full tank. The second valve can then be closed and the first valve
reopened, operating the drain valve and again dumping the contents of the
tank. The first valve is again closed and the second valve opened, this
time to deliver the precharge. One of the liquid level sensors is
positioned to signal when an adequate amount of precharge has been added
to the tank, at which time the second valve is again closed and the cycle
is completed.
DESCRIPTION OF THE DRAWINGS
Further advantages and features of the present invention will be more fully
apparent to those skilled in the art to which the invention pertains from
the ensuing detailed description thereof, regarded in conjunction with the
accompanying drawings wherein like reference characters refer to like
parts throughout and in which:
FIG. 1 illustrates an AUTOMATIC WASTE DUMP AND CLEANING SYSTEM according to
the present invention controlled by a flow meter in idealized diagrammatic
form;
FIG. 2 illustrates a detailed internal view of the electronic module 20 of
FIG. I;
FIG. 3 illustrates a fluid operated drain value;
FIG. 4 illustrates a sectional view of an alternate embodiment of an
AUTOMATIC WASTE DUMP AND CLEANING SYSTEM controlled by a different
flowmeter;
FIG. 5 illustrates a developed view of the cylinder wall of a valve
according to the alternate embodiment; and
FIG. 6 illustrates the alternate embodiment flowmeter of FIG. 4 within the
AUTOMATIC WASTE DUMP AND CLEANING SYSTEM of FIG. 1 in idealized
diagrammatic form.
DETAILED DESCRIPTION
Turning first to FIG. 1, flow meter 10 is interposed in the fluid line
leading to a pair of solenoid valves 12 and 14. A first solenoid valve 12
is normally open and is connected to a waste dump valve system 16. The
valve 12 is normally open so that in the event of a failure, fluid flow
from a service vehicle will operate the waste dump valve, draining all
applied fluid from a waste tank 18. A second, normally closed solenoid
valve 14 is connected to deliver fluid to the waste tank 18.
The flow meter 10 is also connected to an electronic module and delivers a
train of electronic pulses to an electronic counter 22 within the
electronic module 20, see FIG. 2. After a predetermined count of pulses,
the counter 22 energizes and thereby closes the first solenoid valve 12
after a preprogrammed rinsing of the waste tank has been completed. The
second solenoid valve 14 is energized, opening it to deliver a
predetermined precharge quantity of fluid to the waste tank 18.
The flow meter 10, the electronic module 20 and the solenoid valves 12 and
14 are powered by a self-contained power supply 24 which operates with a
rechargeable battery (not shown) that can be "trickle charged" by the
aircraft power supply during flight.
The flow meter controlled system can also be equipped with an electronic
fluid level detector 26 which acts as a back-up, over-fill detector which
will either alarm or shut down the system when the waste tank 18 has been
filled to its maximum operating level. Additional level sensors 27, 27',
27" are provided to signal an empty tank, an interim sensing fill level
and a precharge level, respectively, which can be used in alternative
operating modes, described below.
As cleaning and rinsing fluid is provided to the flow meter 10, a train of
electronic pulses is applied to the counter 22 within the electronic
module 20.
Turning next to FIG. 2, when the electronic counter 22 signals a
predetermined count of electronic pulses, corresponding to a predetermined
volume of fluid, appropriate command signals are generated and applied to
both the first and second solenoid valves through appropriate circuits 28,
causing the closing of the normally open first solenoid valve 12.
Turning to FIG. 3, the initial supply of fluid through the flowmeter 10 and
first solenoid valve 12 is delivered to the waste dump valve assembly 16
The waste dump valve assembly 16 is located within the waste tank 18 which
is installed in the aircraft. A fluid intake line 29 provides fluid from
the normally open first solenoid valve 12 to the waste dump valve assembly
16. The dump valve assembly 16 includes a piston housing 30, a movable
piston 32 and a return spring 34 that is adapted to bias the piston 32
into the fully extended or closed valve configuration.
Coupled to the piston 32, is an actuator rod 36 that terminates in a
self-aligning valve assembly 38, as illustrated in the U.S. Pat. No.
4,338,689. to Zeig. As in Zieg, a bellows assembly 40 surrounds the
actuator rod 36 and tends to exclude the contents of the waste tank 18
from the interior of the bellows 40 and the dump valve assembly 16.
A drain orifice 42 at the base of the tank 18 is normally maintained closed
by the bias on the piston 32 with the valve assembly 38 engaging a valve
seat 44 at the bottom of the tank 18. A pressure relief opening 45 extends
through the fluid intake line 29 to facilitate seating of the valve
assembly 38. At the upper limit of piston travel, a stop assembly 46,
which is part of a cap assembly 48 of the piston housing 30, is provided.
At this position, the fluid freely flows through the interior of the
housing 30 to an outlet conduit 50 which is coupled through a check valve
52 to a spray ring 54.
The continued provision of a flow of fluid to the waste dump valve 16
applies a fluid pressure to the piston 32 sufficient to drive the piston
32 to its upper limit of travel, fully compressing the bias spring 34 and
opening the drain orifice 42. At this point the bellows 40 is compressed
and the self aligning valve assembly 38 is fully disengaged from the drain
orifice 42 of the tank 18, thus draining the tank 18, as seen in phantom
lines.
As fluid is applied to the dump valve assembly 16, once the hydraulically
driven piston 32 moves to its upper limit position, the fluid then goes
through the outlet conduit 50 to start cleaning the waste tank. The spray
and rinse ring 54 applies fluid to the interior surface of the tank which
then drains from the tank through the open drain orifice 42.
As noted above, when a preprogrammed volume of fluid has been delivered
through flowmeter 10 to the first solenoid valve 12, the electronic
counter 22 recognizes a predetermined count and signals the solenoid
valves 12, 14. Closing the first solenoid valve 12 terminates the flow of
fluid to the waste dump valve 16, reducing fluid pressure to the piston
32, which allows the force of the bias spring 34 to prevail, forcing the
piston 32 downward, thereby seating the valve assembly 38 in the valve
seat 44, occluding the drain orifice 42. Any fluid trapped within the
piston housing 30 is expelled through the pressure relief opening 45 into
the waste tank 18.
Fluid continues to be delivered to the flow meter 10 and flows through the
now open second solenoid valve 14 into the waste tank 18 through the rinse
ring assembly 54. Upon delivery of a further predetermined volume of
fluid, sufficient to precharge the waste tank 18, the electronic counter
22 reaches a count which corresponds to that volume, and signals the
second solenoid valve 14, through the control module 28. The valve 14
closes and the system is ready for a new cycle. A pressure switch (not
shown), if installed, can determine when pressurized fluid is no longer
being supplied to the system. In that event, until the pressure drops, the
first valve 12 is held closed. When the signal is removed from the control
module 28, the first solenoid valve 12 returns to its normally open
configuration.
The flow meter controlled system may also be equipped with an electronic
detector 26 which senses the fluid level within the waste tank 18 to
signal the electronic module 20 to close the second solenoid valve 14 in
the event that there is an excess volume of fluid delivered to the waste
tank.
Turning next to FIG. 4, there is shown, in a sectional view, an alternative
flowmeter controlled system 10'. FIG. 6 shows the alternative embodiment
wherein flowmeter 10' is placed within the Automatic Waste Dump and
Cleaning System of FIG. 1. In this embodiment, a positive displacement
flowmeter 62, which is mechanically operated, is connected via an input
shaft to a gear drive 64 which provides a substantial gear reduction. In
one embodiment, a ratio of 250 to 1 was employed. The gear drive 64 is
connected to a control valve cylinder housing 66 through a pressure
operated clutch 68.
The control valve cylinder housing 66 contains a control valve 70 which
includes a control valve cylinder 72 having fluid flow orifices in its
wall and a control valve piston 74 which is coupled to the control valve
cylinder 72 and engages the clutch 68.
The control valve piston 74 provides a linear, downward motion to the
control valve cylinder 72 against a constant force return spring 76 which
is placed at the bottom of the control valve cylinder housing 66.
The control valve cylinder 72 rotates axially on the piston 74 against a
return bias 78. The top of the control valve cylinder housing 66 is
connected to the outlet port of the flowmeter 80, which provides fluid
under pressure to the control valve 70.
The initial supply of cleaning/rinsing fluid under pressure from the
service truck flows through the flowmeter 62, to provide fluid to the
control valve 70, which drives the piston 74 downward, aligning the fluid
flow orifices in the cylinder 72 with outlet ports 84 and 90. The outlet
ports 84 and 90 lead to a waste dump valve that is substantially similar
to the one discussed in the preferred embodiment and to a rinsing means.
The waste dump valve utilized in the alternate embodiment will be referred
to as 16', and all of the elements of the waste dump valve 16' which are
structurally similar to the elements of the waste dump valve of the
preferred embodiment will be identified by similar reference numerals
superscripted by a prime ('). The control valve 70 engages the gear drive
64 through the pressurized clutch 68.
As the fluid flows from the service truck, the flowmeter 62 rotates the
gear drive 64 which transmits this rotational motion, through the engaged
pressurized clutch to the cylinder 72.
Turning next to FIG. 5, the fluid flow orifices are positioned along the
cylinder wall to regulate the flow of fluid to either the waste drain
valve or the rinsing means, based upon the degree of revolution of the
cylinder wall 82. After a predetermined amount of fluid is delivered
through the flowmeter 62 to the control valve 70, the control valve is
driven downward. The fluid flow through the flowmeter 62 has also rotated
the control valve 70 via the gear drive 64 and engaged clutch 68. The
control valve 70 is now in its initial rotational position.
This initial position of the control valve 70 aligns the cylinder wall 82
with the first outlet port 84 such that fluid flows through fluid flow
orifice 86 to the waste dump valve 16'. The continued provision of fluid
under pressure to the waste dump valve 16' disengages the self-aligning
valve assembly 38' from the drain orifice 42', as explained in connection
with FIG. 3 above, thus draining the waste tank 18'.
Upon completion of delivery of the desired amount of fluid to the waste
dump valve 16', the control valve 70 rotates to its second rotational
position. At this second position, flow to the waste dump valve 16'
through the outlet port 84 is stopped and, instead, fluid flows through
orifice 88 to a rinsing system (not shown) through the second outlet port
90.
As in the preferred embodiment, the termination of fluid flow to the waste
dump valve 16' reduces fluid pressure to the piston 32' allowing the force
of the bias spring 34' to prevail, forcing the piston 32' downward and
seating the valve assembly 38' in the valve seat 44', occluding the drain
orifice 42'.
A second desired amount of fluid is then delivered to the rinsing system
which rinses the tank. Some of the fluid will drain from the tank before
the waste dump valve 16' closes fully. Upon completion of delivery of the
second desired amount of fluid, the control valve 70 has rotated to a
third position, terminating the flow of fluid through orifice 88 and
outlet port 90.
At its third position, the control valve 70 once again allows fluid to flow
to the waste dump valve 16', this time by alignment of the outlet port 84
with the orifice 92. The piston 32' is again driven upward and the drain
orifice 42' is again opened, allowing any rinsing fluid which remains in
the tank to be drained.
Upon provision of a desired amount of fluid through orifice 92, the control
valve cylinder 72 rotates to a fourth position, terminating all flow to
the waste dump valve 16' via outlet port 84. Orifice 94 is aligned with
outlet port 90, again allowing fluid to rinse the tank and providing a
"precharge" for servicing the aircraft. It is clear that this cycle of
operation can also
be programmed into the system of the preferred embodiment.
In yet an additional embodiment, the flow meter is adapted to operate a
preprogrammed cam through a timing gear, clutch and return bias
arrangement. The cam is programmed to operate a pair of flow | | |
