High speed engine coolant flush and filtration system and method

Information

  • Patent Grant
  • 6637468
  • Patent Number
    6,637,468
  • Date Filed
    Friday, July 14, 2000
    24 years ago
  • Date Issued
    Tuesday, October 28, 2003
    21 years ago
  • Inventors
  • Examiners
    • Maust; Timothy L.
    Agents
    • Gray Cary Ware & Freidenrich LLP
Abstract
A high-speed cleaning system and method in which a liquid is injected by-compressed air into the vacuumed chambers in the automotive cooling systems, in water-cooled engines. The liquid is injected in short period time under pressure, and the cooling system is pre-evacuated and held at a vacuum so that there is no flow restriction to build up high pressure in the cooling system in the short period of time the liquid is injected in the cooling system, and the liquid travels through the cooling system at a high rate of speed. High pressure air is mixed with the liquid before it is injected into engine cooling system, where the liquid/air mixture travels at a high rate of speed creating a hurricane type effect that breaking loose contaminants such as dirt, rust, and other particles and washes them out of the engine cooling system.
Description




FIELD OF THE INVENTION




The present invention relates to flushing of liquid cooling systems, and more particularly to a system and apparatus for quickly evacuating, cleaning and refilling a liquid cooling system such as an engine cooling system.




BACKGROUND OF THE INVENTION




It is well known that over time, contaminants such as rust, scale, particulates and sludge build up in liquid cooling systems such as engine cooling systems. These contaminants get baked onto cooling system components, reducing the efficiency and lifetime of cooling system components. Periodically, not only does the liquid coolant need replacement, but also the coolant system itself should be flushed to remove some of the contamination deposited throughout the cooling system.




Unfortunately, most commercially available coolant flushing systems fail to provide a cleaning action inside the chambers, hoses and other cooling system components to adequately remove interior contamination. Simply running a coolant or cleaning fluid through the system fails to remove these baked on contaminants from the system. Even increasing the flow rate through the system has limited success because there is a limitation on the overall pressure that can safely be applied to the cooling system without damaging it. Even adding entrained gas bubbles to the flushing liquid has been proposed, but that simply does not create a cleansing action inside the cooling system that effectively removes the; contamination. Such flushing systems also fail to provide a convenient way of removing, : filtering, recycling and replenishing coolant for the cooling system, especially in a manner that minimizes coolant waste and hazardous spills.




There is a need for an apparatus and method that creates a superior cleansing action inside a liquid cooling system for removing contamination therein, and in a way that conveniently removes filters, recycles and replenishes coolant from the cooling system.




SUMMARY OF THE INVENTION




The present invention solves the aforementioned problems by providing an apparatus and method which utilizes a relatively high proportion of air in the flushing liquid, together with a vacuum applied to the outlet of the cooling system, to create a high speed hurricane-like effect for effectively removing contamination within the cooling system.




The apparatus for flushing contaminants from a liquid coolant circulation system includes an injection hose connectable to an injection point of the coolant circulation system, an evacuation hose connectable to an extraction point of the coolant circulation system, a liquid supply for supplying liquid under pressure to the injection hose and the injection point, a vacuum motor connected to the evacuation hose for applying a vacuum to the evacuation hose and the extraction point, a gas inlet for receiving compressed gas and for mixing the compressed gas with the liquid supplied by the liquid supply to form a liquid and gas mixture. The liquid and gas mixture enters the coolant circulation system at the injection point, travels through the coolant circulation system at a high rate of speed, and is extracted from the coolant circulation system at the extraction point by the evacuation hose.




In another aspect of the present invention, the apparatus for flushing contaminants from an internal combustion engine cooling system, which includes a cooling radiator and a heating radiator both connected to an engine block with liquid coolant lines comprises an injection hose terminating in an injector that is connectable to the engine block to define an injection point into the engine cooling system, an evacuation hose terminating in a connector assembly that is connectable to one of cooling radiator and the heating radiator to define a first extraction point from the engine cooling system, a liquid supply for supplying liquid under pressure to the injection hose and the injection point, a vacuum motor connected to the evacuation hose for applying a vacuum to the evacuation hose and the first extraction point, a gas inlet for receiving compressed gas and for mixing the compressed gas with the liquid supplied by the liquid supply to form a liquid and gas mixture. The liquid and gas mixture enters the engine cooling system at the injection point, travels through the engine block and heating radiator and cooling radiator at a high rate of speed, and is extracted from the engine cooling system at the extraction point by the evacuation hose.




In one additional aspect of the present invention, the method of the present invention for flushing contaminants from an internal combustion engine cooling system, which includes a cooling radiator and a heating radiator both connected to an engine block with liquid coolant lines and points of injection and extraction, comprises the steps of mixing a liquid with a gas to create a liquid/gas mixture, injecting the liquid/gas mixture into an injection point of the engine cooling system under pressure and applying a vacuum to an extraction point of the engine cooling system to evacuate the liquid/gas mixture through the extraction point.











Other objects and features of the present invention will become apparent by a review of the specification claims and appended figures.




BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a plan view of the flush and filtration system of the present invention.





FIG. 2A

is a schematic diagram of the overall flush and filtration system of the present invention.





FIG. 2B

is a schematic diagram of the timer and control board circuit.





FIG. 2C

is a schematic diagram of the timer circuit.





FIG. 3A

is aside cross-sectional view of the liquid pre-charge tank


121


.





FIG. 3B

is a perspective view of the liquid pre-charge tank


121


.





FIG. 4A

is a side cross-sectional view of outlet fitting


105


.





FIG. 4B

is a side view of outlet fitting


105


.





FIG. 5A

is a perspective view of vacuum joint


200


.





FIG. 5B

is an cross-sectional view of vacuum joint


200


.





FIG. 6

is a perspective view of seal


205


.





FIG. 7A

is a perspective view of retainer


202


.





FIG. 7B

is a side cross-sectional view of retainer


202


.





FIG. 8A

is a perspective-view of radiator filler adapter


201


.





FIG. 8B

is a side cross-sectional view of radiator filler adapter


201


.





FIG. 9A

is a perspective view of radiator hose adapter


203


.





FIG. 9B

is a side cross-sectional view of radiator hose adapter


203


.





FIG. 10

is a side view of pressure switch


1604


-


a.







FIG. 11A

is a perspective view of thread type filler adapter body


207


.





FIG. 11B

is a side cross-sectional view of thread type filler adapter body


207


.





FIG. 12A

is perspective view of thread type filler adapter female cap


208


.





FIG. 12B

is side cross-sectional view of thread type filler adapter female cap


208


.





FIG. 13

is an exploded perspective view of vacuum adapter assembly A


240


.





FIG. 14

is a partially exploded perspective view of vacuum adapter assembly A


240


.





FIG. 15A

is an exploded view of vacuum adapter assembly A


260


for connection to a radiator filler.





FIG. 15B

is a partially exploded view of vacuum adapter assembly A


260


for connection to a radiator filler.





FIG. 16A

is a partially exploded view of vacuum assembly A


250


, for connection to a radiator hose.





FIG. 16B

is an exploded view of vacuum assembly A


250


for connection to a radiator hose.





FIG. 17A

is a perspective view of pressure switch


1604


.





FIG. 17B

is a cross-sectional view of pressure switch


1604


, with the switch in its open position.





FIG. 17C

is a cross-sectional view of pressure switch


1604


, with the switch in its closed position.





FIG. 18A

is a exploded cross-sectional view of injector nozzle assembly


303


.





FIG. 18B

is a perspective exploded view of injector nozzle


303


assembly with pressure switch


1604




b.







FIG. 19

is a partial perspective view of vacuum hose


305


.





FIG. 20A

is a side cross-sectional view of heater hose adapter


304


.





FIG. 20B

is a perspective view of heater hose adapter


304


.





FIG. 21A

is a side cross-sectional view of large hose adapter


306


.





FIG. 21B

is a perspective view of large hose adapter


306


.





FIG. 22

is an exploded view of hose plug


308


, seal


205




b


and hose adapter


306


.





FIG. 23A

is an exploded view of output hose assembly A


350


.





FIG. 23B

is an exploded view of vacuum hose assembly A


360


.





FIG. 23C

is an exploded view of output hose assembly A


370


.





FIG. 23D

is an exploded view of output hose assembly A


380


.





FIG. 24

is a plan view of a conventional internal combustion engine cooling system


400


.





FIG. 25

is a cross-section plan view of the flush and filtration system of the present invention connected to a conventional engine cooling system.





FIG. 26

is a cross-sectional plan view of the a first connection configuration of the flush and filtration system of the present invention to a conventional engine cooling system.





FIG. 27

is a cross-sectional plan view of the a second connection configuration of the flush and filtration system of the present invention to a conventional engine cooling system.





FIG. 28

is a cross-sectional plan view of the a third connection configuration of the flush and filtration system of the present invention to a conventional engine cooling system.





FIG. 29

is a cross-sectional plan view of the connection between the flush and filtration system of the present invention and a conventional engine cooling system, for refilling thereof.





FIG. 30

is a cross-sectional plan view of the Mush and filtration system of the present invention for transfer of coolant to another container.





FIG. 31

is a cross-sectional plan view of the flush and filtration system configuration of the present invention for recycling and filtering old coolant.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS




The present invention is a mobile liquid injection flush and filtration system


100


, as illustrated in

FIG. 1

, for cleaning liquid cooling systems (i.e. a car engine cooling system), and filtering and recycling coolant fluid.




A typical internal combustion engine cooling system is illustrated in

FIG. 24

, and includes a coolant recover tank


401


, an overflow hose


402


, a radiator cap


403


, a coolant filler


404


, a radiator


405


, an upper hose neck


406


, a lower hose neck


407


, an upper radiator hose


408


, a thermostat housing


409


, a thermostat


410


, a water pump


41


a water pump coolant inlet


412


, a lower radiator hose


413


, a heater return inlet


414


, a heater return hose


415


, cylinder head coolant chambers


41


.


6


, a heater return outlet


417


, a heater core


418


, a heater inlet


419


, a heater control valve


420


, a heater control line


421


, a heater inlet hose


422


, a hot water outlet


423


, and engine block coolant chambers


424


, all configured as illustrated in FIG.


24


.




The liquid flush and filtration system


100


of the present invention (best illustrated in

FIG. 1

) includes a vacuum assembly


101


(comprising a liquid/air vacuum motor


1013


and tank


1012


), liquid pumps


103




a


and


103




b


; filters


107




a


,


107




b


,


107




c


; a coolant tank


108


; one-way valves


109




a


,


109




b


,


109




c


,


109




d


,


109




e


; pressure gauges


106




a


,


106




b


and


106




c


; electrically controlled valves (filter bypass valve


114


, filter control valve


115


, outlet cut-off valve


110


, pre-charge control valve


112


, and air control valve


124


); a liquid pre-charge tank


121


that includes level sensors SL


1


, SL


2


, SL


3


(see FIG.


3


); an adjustable air bypass valve


123


; an adjustable air pressure regulator


126


; an air reserve tank


128


, a compressed air inlet


127


; and pressure sensors


1604


-


a


and


1604


-


b


(see FIGS.


10


and


17


A-C); all connected together as shown in

FIG. 1

using pipes


102


and


122


. An electrical contrller


160


operates, and receives data from, the electrical devices as shown in FIG.


1


.




The flush and filtration system


100


includes an output assembly A


350


, A


370


or A


380


for connection to the engine cooling system (see

FIGS. 23A

, C and D). Each of these output assemblies include an output hose


302


. and seal


205




b


. In output assembly A


350


, output hose


302


terminates in a liquid/air injector


303


assembly that includes a liquid/air injector


303




b


having a reduced diameter to accelerate liquid/air as it is injected into the engine cooling system (see

FIGS. 18A-B



23


A and


26


-


27


), and a hose adapter


303




a


for attachment to output hose


302


. Pressure sensor


1604


-


b


inserts into injector


303




b


to measure the pressure therein. In output assembly A


370


, output hose


302


terminates in a hose plug


306


having a plurality of outer diameters to attach to the engine cooling system (

FIGS. 21

A-B,


23


C and


28


), or hose plug


306


can be sealed by a plug


308


(

FIG. 22

) for temporarily sealing the thermostat housing


409


(see FIG.


27


). In output assembly A


380


, output hose


302


terminates in a hand held liquid control valve


307


for manually and selectively filling the engine cooling system (

FIGS. 23D and 29

) or an external container (

FIG. 30

) with liquid coolant.




Flush and filtration system


100


further includes a vacuum hose


305


attached to tank


1012


that terminates in a vacuum assembly A


240


, A


250


or A


260


for connection to (and liquid/air evacuation from) the engine cooling system (see FIGS.


1


and


25


-


29


). Vacuum assembly A


240


includes vacuum joint


200


, seals


205




a


and


205




b


, cap


301


and coolant tank adapter


207


/


208


(see

FIGS. 5-6

and


11


-


14


), for connection to certain threaded coolant filler openings on some vehicles. Vacuum assembly A


250


includes vacuum joint


200


, seal


205




b


, cap


301


and radiator hose adapter


203


(see

FIGS. 5A-B

,


9


A-B and


16


A-B), for connection to the radiator and vacuum hose of the engine cooling system (see FIGS.


27


-


28


). Vacuum assembly A


260


includes vacuum joint


200


, seals


205


and


205




b


, cap


301


, retainer


202


and radiator filler adapter


201


(see

FIGS. 5-8

and


16


A-B), for connection to the radiator filler and vacuum hose of the engine cooling system (see FIGS.


25


-


26


). Cap


301


seals off vacuum joint aperture


200




a


when not attached to hose


302




a


(as further explained below).




Hose assembly A


360


includes hose


302




a


that terminates in a hose adapter


304


having a plurality of outer diameters for connection to various diameters of heater hoses found in engine cooling systems (

FIGS. 20

,


23


B and


26


-


27


). The input of hose


302




a


attaches to vacuum joint aperture


200




a


in certain configurations (see FIGS.


26


and


27


).




Electrical Control Circuit




The basic operation of the engine cooling system


100


is as follows. The engine cooling system is pre-evacuated by applying both pressurized air and a vacuum to the engine cooling system. The liquid pre-charge tank


121


is filled up with coolant, which is then mixed with pressurized air and injected into the cooling system. The liquid/air mixture rushes through the cooling system and is evacuated using a vacuum applied to the point(s) of extraction. The system can recycle the evacuated coolant by filtration and re-injection. A more detailed description of the system operation is discussed in the next section.




The electrical control circuitry of controller


160


is shown in

FIGS. 2A-2C

. AC power is supplied through the power plug PLG and through fuse F


1


, which is a shock circuit breaker for AC power circuit protection. PR


1


is a main power relay, connecting power from F


1


to transformer T


1


; vacuum union power relay PR


10


, and all the electrical control valves


124


,


112


,


110


,


114


, and


115


. The control valves


124


,


112


,


110


,


114


,


115


are controlled by control board


160




a


(see FIGS.


2


A and


2


B).




A 12 volt DC power source (battery BAT) provides power for the control circuitry (function switch FSW and control board


160




a


), and two DC power liquid pumps


103




a


and


103




b


. Battery BAT is recharged by transformer T


1


and rectifier RD


1


. A main DC power protection fuse F


3


is connected between battery BAT and a main power control switch SW


1


which controls AC power relay PR


1


and all the control-circuits. Switch SW


1


connects F


3


to main power relay PR


1


, fuse F


2


and fuse F


4


. Fuse F


2


is a control-circuit protection fuse connecting function switch FSW to timer and control board


160




a


(see FIG.


2


B). Fuse F


4


is a protection fuse for liquid pumps


103




a


and


103




b


and relays PR


103




a


and PR103


b.






When switch SW


1


is “off”, the electrical control is disabled. When SW


1


is “on”,the DC power is supplied to relay PR


1


, and AC power is “on” so the battery BAT begins to charge up and AC power is applied to relay PR


101


and to lead


24


of control board


160




a


. DC power is applied to relays PR


103




b


and PR


103




a


, and to function switch FSW. Also, DC power is applied to control board


160




a


, through resistor R


18


, to provide a 1.2 DC voltage to turn on solid state relay SSR


4


. Also, DC power supplied through resistor R


10


on control board


160




a


provides power for timer IC


555


. C


2


is a power stabilizer capacitor to prevent interrupted signal, and resistor R


4


provides high voltage to keep the trigger in timer IC


555


in its “off” condition. With function switch FSW in the “0” position, all the functions are inactive.




1. Evacuating Functions




When function switch FSW is moved to its on “1” position, then main switch SW


1


is turned “on”, the 12 volt power from the al terminal of switch FSW is applied to lead


13


of control board


160




a


, through diode D


4


and to lead


33


, which connects to vacuum power relay PR


101


to turn on the motor


1013


in vacuum assembly


101


for applying a vacuum to the engine cooling system. Indicator light L


1


is also lit. Resistor R


21


is voltage reducer resistor. Diode D


5


does not allow current from diode D


4


to pass to lead


14


, so there is no power supplied to indicator light L


2


and PR


103




a


. With function switch FSW selected to terminal b


1


, power is applied to menu air injection switch SW


7


, wherein diode D


1


(in

FIG. 2A

) prevents any current from passing to and activating the b


2


terminal circuit. When switch SW


7


is pressed, DC power passes to lead


8


of control board


160




a


, and on through resistor R


17


, diode D


3


and resistor R


14


. Resistors R


14


and R


15


form a voltage divider to provide a 1.2 volt at the trigger of relay SSR


3


, which actives relay SSR


3


to supply 115 volt AC power to cut-off valve


110


, opening the valve. Current from R


17


passes through resistor R


13


and activates indicator light L


5


. Current from R


17


also passes through resistors R


6


and R


2


and on to ground. The voltage at the trigger of relay SSR


1


is 1.2 volts, so that when relay SSR


1


is activated, 115 volt AC power is applied air control valve


124


to inject air into to engine cooling system. The high speed air from air control valve


124


blows coolant out of the engine cooling system as further described below under system operation. When evacuation is complete, switch SW


7


is released.




2. Cleaning Function




The cleaning operation is an automatic function using the level sensors SL


1


-SL


3


and a timer circuit to start and stop liquid/air injection. Timer IC


555


is used in the timer control circuit (FIG.


2


C), where pin I is ground, pin


2


is trigger, pin


3


is output, pin


4


is reset, pin


5


is control voltage, pin


6


is threshold, pin


7


is discharge, and pin


8


is power supply (4.5v to 15v).




When function switch FSW is turned to position “2”,then main switch SW


1


is turned “on”, and the DC power from pin a


2


of function switch FSW is supplied to lead


14


of control board


160




a


, lamp L


2


and resistor R


22


and on to ground, which lights up indicator light L


2


. Diode D


4


isolates power from D


5


and pin


13


. Current passes through diode D


5


and on to lead


33


of control board


160




a


to activate relay PR


101


which turns on vacuum assembly


101


. Also, current passes through diode D


6


and lead


32


of control board


160




a


to activate the relay PR


103




a


, which turns on liquid pump


103




a


. Diode D


7


isolates power from leads


32


and


15


of control board


160




a


. Also power from diode D


6


passes through resistors R


20


and R


19


and on to ground, whereby 1.2 volts are applied to lead


12


of control board


160




a


, which then goes to filter bypass switch BPW.




Bypass switch BPW can be selected to filter the liquid or to bypass the filters when filling liquid precharge tank


121


from tank


1012


. To filter liquid from liquid pump


103




a


, bypass switch BPW is moved to position “2”,whereby 1.2 volts is applied to lead


11


of control board


160




a


to activate relay SSR


6


, which closes the filter bypass control valve


114


. With filter control valve


115


opened, liquid pumped from pump


103




a


passes through filters


107




a


and


107




b


, and filter


107




c


(see FIG.


1


), then through valve


115


, one way valve


109




b


, pre-charge control valve


112


, one way valve


109




d


and then into liquid pre-charge tank


121


. To bypass filtering of liquid from pump


103




a


, bypass switch BPW is moved to position “1”, whereby 1.2 volts is applied to lead


10


of control board


160




a


to activate relay SSR


5


, which opens filter bypass valve


114


and closes filter control valve


115


. No liquid can pass through filters


107




a-c


, and liquid from pump


103




a


will go directly to one way valve


109




b


, precharge control valve


112


, one way valve


109




d


and into liquid pre-charge tank


121


.




When function switch FSW is positioned on pin b


2


thereof, DC power is delivered to lead


6


of control board


160




a


, and then to collector C of transistor TR


1


(FIGS.


2


B and


2


C). Power is also applied to resistors R


7


and R


8


, then goes to ground, whereby the trigger in relay SSR


2


receives 1.2 volts which actives SSR


2


to open liquid pre-charge control valve


112


so that liquid from pump


103




a


can fill liquid pre-charge tank


121


. The DC power from switch SW


1


is applied to lead


5


of control board


160




a


. Resistor R


10


and capacitor C


2


are a voltage stabilizer to avoid interrupted signals that trigger the timer, so capacitor C


3


is discharged by pin


7


of IC


555


. Resistor R


5


reduces the control voltage, so that when the liquid in the liquid pre-charge tank


121


has not reached selected level (i.e. the level sensors SL


1


-SL


3


are open), resistor R


4


applies a voltage to pin


2


of timer IC


555


and the timer IC


555


stays in an “off” condition. When the liquid in tank


121


fills up to the selected level, the appropriate level sensor SL


1


, SL


2


, or SL


3


is grounded by water and the voltage at pin


2


of timer IC


555


drops to 0, whereby the timer is triggered. Discharge pin


7


is then off (open to ground), and current from resistor R


10


passes through resistor R


3


and variable resistor VR to begin charging up capacitor C


1


. Variable resistor VR adjusts the charge time from 5 seconds to 20 seconds. When capacitor C


1


charges up to a voltage equivalent to that of pin


5


of timer IC


555


, the threshold at pin


6


of timer IC


555


turns off the timer and turns on discharge (closed to ground) t pin


7


of timer IC


555


, whereby capacitor C


1


discharges again, and pin


4


of timer IC


555


resets the timer which then waits for next trigger signal.




When the timer has been triggered, the output pin


3




0


f timer IC


555


goes high, and current goes through resistor R


9


and to base B of TR


1


, whereby the gate of TR


1


is opened and current from lead


6


of control board


106




a


passes through pins C and E of TR


1


, through diode D


2


and resistor R


13


and light L


5


(which lights up light L


5


) and on to ground. This current also passes through resistors R


6


and R


2


and on to ground, whereby 1.2 volts is supplied to the trigger of relay SSR


1


, which turns on air control valve


124


. The power from diodes D


2


and D


3


, and resistors R


14


and R


15


then goes to ground, which activates relay SSR


3


to turn on outlet cut-off valve


110


, which causes air and liquid to be injected into the engine cooling system via output hose


302


. Once all the liquid is injected, air is continually injected to evacuate engine cooling system. Then, the timer stops, valves


124


and


110


are closed, and pre-charge tank


121


is refilled with liquid.




If the pressure in engine cooling system is over the pressure limit during liquid/air injection, the pressure switches


1604


-


a


or


1604


-


b


sense the excessive pressure and ground lead


9


of control board


160




a


. The trigger voltage in relay SSR


4


will then go to 0 volts, the relay SSR


4


turns off AC power on relays SSR


1


, SSR


2


and SSR


3


so the valves


124


,


112


and


110


will close immediately to cut off liquid/air injection flows. Resistor R


118


reduces voltage from pin number


5


on timer and control board


160




a


, which provides 1.2 volts to the trigger of relay SSR


4


, which controls AC power to relays SSR


1


, SSR


2


and SSR


3


. When pressure switches


1604


-


a


or


1604


-


b


are grounded, relay SSR


4


will inactive. When pressure switches


1604


-


a


and


1604


-


b


are opened, power from lead


5


of control board


160




a


is applied through resistor R


18


to capacitor C


4


, whereby the voltage in the trigger of relay SSR


4


has a small delay to reach up to 1.2 volts while capacitor C


4


charges up, which then re-actives relay SSR


4


, to prevent high frequency pressure vibrations.




The cleaning cycles over and over, until engine cooling system is clean (as further explained below). To stop all the functions, the user simply needs to just turn off the main power switch SW


1


.




3. Filling Coolant With Coolant in Vacuum Tank or Refiltering Over Old Coolant




When function switch FSW is moved to position “


3


” and switch SW


1


is turned “on”, the power from pin b


3


is applied to lead


7


of control board


160




a


, through resistors R


16


, R


14


and R


15


, and then on to ground. The diode D


3


isolates the power from resistor R


16


and diode D


2


, so that the trigger of SSR


3


receives 1.2 volts of power to activate SSR


3


to turn on outlet cut off control valve


110


, which allows liquid to exit into the output hose


302


. Power from pin a


3


of function switch FSW is applied to lead


15


of control board


160




a


, whereby current passes through light L


3


(which lights up) and R


23


, and then goes on to ground. Power also passes through diode D


7


and lead


32


of control board


160




a


, to activate relay PR


103




a


which in turn activates liquid pump


103




a


. Also, 1.2 volts is applied to lead


12


of control board


160




a


, whereby the bypass switch BPW can be positioned to filter control “on” for filtering or to bypass “on” to bypass filtering. Diode D


6


isolates power to lead


14


of control board


160




a.






The liquid pump


103




a


draws liquid out from vacuum tank


1012


, and pumps it (either filtered or unfiltered) to fill the engine cooling system with the set up shown in

FIGS. 26-29

, or can be transferred to another container as shown in FIG.


30


. To filter but maintain the liquid in tank


1012


, with filter control valve


115


“on”,and with bypass switch BPW turned to position “2”, the output hose


302


is simply positioned to output the liquid back into tank


1012


, as shown in FIG.


31


.




4. Filling New Coolant From New Coolant Tank(


108


)




With function switch FSW turned to position “


4


”,and the main power switch turned to “on”,power is applied to lead


7


of control board


160




a


, through resistors R


16


, R


14


and R


15


, and then on to ground, whereby 1.2 volts actives relay SSR


3


, which opens outlet cut off valve


110


. Power is also applied to pin a


4


of function switch FSW, which passes through indicator light L


4


(lighting it up) and resistor R


24


, and then on to ground. Current also goes through diode D


8


to lead


31


of control board


160




a


, which actives relay PR


103




b


to turn on liquid pump


103




b


. Pump


103




b


draws coolant from tank


108


and pumps it through one way valves


109




a


and


109




b


, through cut off valve


110


and outlet fitting


105


, out through output hose


302


in any of the set ups shown in

FIGS. 26-29

.




Operation of Invention




1. Evacuation of Engine Coolant:




To start the flush and filtration of the engine cooling system, the engine is started, the vehicle heater is turned on, the temperature control in the vehicle is switched to warm so the heater control valve


420


(in

FIG. 24

) in the vehicle is opened and then the engine is turned off. The system


100


(in

FIG. 1

) is connected to the engine cooling system as shown in

FIG. 25

, by removing the radiator cap


403


from the radiator filler hole


404


and placing the radiator filler vacuum assembly A


260


on radiator filler hole


404


. The other end of vacuum hose


305


is connected to vacuum port


1011


of tank


1012


. The main power switch SW


1


is checked to be in its off position, and electrical power plug PLG is connected to a shop source power outlet, and air inlet


127


is connected to a shop source of compressed air.




The function switch FSW is turned to position “1” and vacuum switch SW


101


on vacuum assembly


101


is turned on. Then, the main power switch SW


1


(

FIG. 2

) is turned on which activates motor


1013


to create a vacuum in tank


1012


, whereby the vacuum from the vacuum assembly


101


is applied to the top of radiator


405


. The coolant in the coolant recovery tank


401


will be sucked out through overflow hose


402


coolant filter


404


, radiator vacuum assembly A


260


, main vacuum hose


305


, and into tank


1012


. The heater hose


415


is then disconnected from the heater hose fitting


414


, whereby at this time no coolant will leak out because of the vacuum applied to the engine cooling system. The engine coolant and outside air from the engine cooling system will be drawn through the elements of the engine cooling system and out through main vacuum hose


305


, whereby the coolant in the cooling system is about 40% to 70% evacuated.




The flush and filtration system


100


is then configured in one of three typical configurations as shown in

FIGS. 26

,


27


or


28


. As shown in

FIG. 26

, the liquid/air injector


303


of output assembly A


350


is attached to the heater return inlet


414


, and hose assembly A


360


is connected between vacuum joint aperture


200




a


of vacuum joint


200


and heater return hose


415


. There is a single point of injection (at the heater return inlet), and two points of extraction (at the heater return hose


415


and the radiator filler hole


404


). In

FIG. 27

, the liquid/air injector


303


of output assembly A


350


is attached to the heater return inlet


414


, the radiator cap


403


is replaced onto coolant filler


404


, vacuum assembly A


250


is attached to the radiator inlet using the hose from the thermostat housing


409


(which is blocked by hose plug


306


and plug


308


), and hose assembly A


360


is connected between vacuum joint aperture


200




a


of vacuum joint


200


and heater return hose


415


. There is a single point of injection (at the heater return inlet), and two points of extraction (at the heater return hose


415


and the radiator inlet). In

FIG. 28

, the hose plug


306


of output assembly A


370


is attached to the radiator hose leading to the thermostat housing


409


after the thermostat


410


has been removed, the radiator cap


403


is replaced onto coolant filler


404


, vacuum assembly A


250


is attached to the radiator inlet (with plug


301


inserted to seal off vacuum joint aperture


200




a


), and heater return hose


415


is reattached to heater return inlet


414


. There is a single point of injection (at the thermostat housing


409


), and one point of extraction (at the radiator inlet).




Function switch is in its “1” position so that when switch SW


1


is activated, motor


1013


is started, which creates a vacuum in tank


1012


, vacuum hose


305


and therefore radiator


405


. Air regulator


126


is adjusted to 80 pounds per square inch (as read on pressure gauge


125


. Switch SW


7


is then held down for 4 to 8 seconds, which activates air control valve


124


and outlet cut off valve


110


so that high pressure air from compressed air inlet


127


and from air reserve tank


128


passes through air control valve


124


, liquid precharge tank


121


, one-way valve


109




c


, cut off valve


110


, and outlet fitting


105


. The high pressure air also travels through adjustable bypass valve


1223


and one way valve


109




e


, and then mixes with any out-going liquid passing through cut-off valve


110


. For evacuation, precharge tank


121


is empty of any liquid, so only the compressed air is injected into the vacuumed chambers of the engine cooling system to carry out almost all of the coolant in the engine into the vacuum tank


1012


. Once the evacuation is complete, and main power switch SW


1


is turned off.




2. Power Cleaning the Engine Cooling System:




With the flush and filtration system


100


in one of the configurations shown in Figures


26


-


28


, and preferably after the coolant has been evacuated as described above, the air pressure at air regulator


126


is adjusted to between about 45 psi and 65 psi The function switch FSW is moved to position “2”,and coolant level switch SW


6


is selected to provide the desired coolant level in the coolant pre charge tank


121


. In the preferred embodiment, each of the level sensors SL


1


, SL


2


, SL


3


correspond to about one half gallon of liquid, and it is recommended to set switch SW


6


so that coolant pre charge tank


121


fills with coolant approximately equal to one third of the engine coolant system capacity or lees. The coolant level in vacuum tank


1012


is checked, which will serve as the flush and filtration fluid, whereby coolant is added if necessary.




Then the main power switch SW


1


is turned on, whereby liquid pump


103


A draws coolant from the vacuum tank


1012


(in

FIG. 1

) and pumps it through filters


107




a


,


107




b


and


107




d


(the filter bypass switch BPW can be selected to close filter control valve


115


and open bypass control valve


114


to bypass filtering). With the liquid pre-charge valve


112


in its open position the coolant from vacuum tank


1012


passes through liquid pre-charge valve


112


and one way check valve


109




d


and into the liquid pre-charge tank


121


. The air bypass valve


123


is also adjusted to its open position whereby the air in the liquid pre-charge tank


121


will escape through valve


123


, one way valve


109




e


, outlet


105


and hose


302


(allowing liquid to freely fill liquid pre-charge tank


121


.




When the coolant fills Lip to the selected level in the liquid pre-charge tank


121


, the appropriate sensor (SL


1


, SL


2


or SL


3


) will trigger control board


160




a


, whereby the timer IC


555


will start. The liquid/air injection times are set by time length control VR. When the timer IC


555


starts the air control valve


124


and cut-off valve


110


are opened, whereby pressurized air from air inlet


127


is directed into liquid precharge tank


121


which forces the coolant therein out through one way valve


109




c


, cut-off valve


110


and outlet fitting


105


. Some of the pressurized air from inlet


127


is diverted around precharge tank


121


, whereby it travels through air bypass valve


123


and one way valve


109




e


, and mixes with the outgoing liquid exiting outlet fitting


105


. The amount of air mixed with the outgoing wash fluid is adjustable by adjusting air bypass valve


123


(opening air bypass valve


123


increases the amount of air eventually mixed with the outgoing liquid).




It has been determined that if the air mixed with the outgoing liquid forms at least 25% of the outgoing liquid/air mixture, that a superior hurricane-like effect cleaning action occurs because the liquid will separate to small groups and resistance inside the cooling system is reduced, thus increasing the speed of the liquid/air mixture as it passes through the engine cooling system. The speed of the liquid/air flow is further increased by the vacuum applied to the liquid/air extraction point(s) of the engine cooling system by vacuum hose


305


connected to the engine cooling system. The high speed of the liquid/air mixture causes a hurricane effect within the cooling system, effectively dislodging scale and rust deposits that are removed with the liquid wash. After all the liquid from precharge tank


121


is injected into the cooling system, the high pressure air continues to be injected, whereby the pressurized air, in combination with the vacuum applied by vacuum hose


305


, evacuates the engine cooling system before the injection cycle ends.




If the pressure in the engine cooling system exceeds a safe pressure limit during the liquid/air injection cycle, pressure switches


1604


-


a


or


1604


-


b


will turn off the outlet cut-off valve


110


and air control valve


124


to cease the liquid/air injection to prevent any damage to the engine cooling system. In the preferred embodiment, pressure switches


1604


-


a


and


1604


-


b


are set to be triggered by a pressure of approximately 30 psi, since most engine cooling systems can safely withstand a pressure of 40 psi. In the short period of time it takes to complete the injection cycle, however, high pressure does not build up in the engine cooling system, but a powerful high-speed liquid wash does flush through the cooling system taking with it much of the contaminates that have built up over time.




After all the washing fluid is evacuated from the engine cooling system, the timer is topped, valves


110


and


124


are closed, liquid is refilled into precharge tank


121


, and the injection operation cycle is repeated several times until the engine cooling system is completely clean. The clean condition of the system can be checked with a visual check of the clear filter cups in which the filters


107




a-c


are housed. After the engine cooling system is clean and evacuated, switch SW


1


(in

FIG. 1

) is turned off, whereby the system is ready to refill coolant back into the engine cooling system.




3. Filtering and Recycling Old Coolant:




A configuration to filter old coolant is shown in

FIG. 31

, where the output end of output hose


302


is inserted into vacuum port


1011


of tank


1012


. When the function switch FSW is turned to position “3” and filter bypass switch BPW is turned off (where control valve


115


is open and bypass valve


114


is closed); and switch SW


1


is turned on, liquid pump


103


A draws coolant from tank


1012


and pumps it through the filters


107




a


,


107




b


,


107




c


, and on through valve


115


, one way valve


109




b


, cut off valve


110


, outlet fitting


105


, and through outlet hose assembly


302


back into vacuum tank


1012


. The pressure gauges


106




a


,


106




b


,


106




c


monitor the condition of filters


107




a


,


107




b


,


107




c


. A high pressure reading differential across the filters indicates that the filters need replacing. In the preferred embodiment, the filter cups surrounding filters


107




a-c


are clear, thus providing a visual indication of how dirty the filters are.




After the coolant is cleaned, it is ready for transfer to an external storage tank


500


(shown in

FIG. 30

) or to be refilled into the engine cooling system (as shown in FIG.


29


).




Cleaned coolant freezing-temperature point and H. P. level should be checked, whereby concentrated coolant or coolant additives can be added to fix the freezing point or H. P. levels.




4. Filling Coolant Into the Engine Cooling System:




After the engine cooling system is cleaned, the same connection is kept as shown in

FIG. 26

,


27


or


28


. Coolant from vacuum tank


1012


can be refilled into the engine cooling system by setting function switch FSW to position “3” and turning on the main switch SW


1


. Alternately, new coolant stored in coolant tank


108


can be filled into the engine cooling system by placing function switch FSW to position “4” and the main switch SW


1


turned on, whereby liquid pump


103


B pumps coolant from coolant tank


108


through one way valves


109




a


and


109




b


, cutoff valve


110


, outlet fitting


105


, and out through output hose


302


.

FIG. 29

illustrates using a handheld valve


307


to refill the radiator with coolant. When coolant fills up to about 70% of the engine coolant capacity, all electrical switches are turned off, flush and filtration system


100


is disconnected from the engine, and the engine cooling system is reconnected back to its original condition. The engine is started and warmed up until the thermostats are open and the engine coolant is circulated in the engine cooling system, and the cooling system topped off with coolant after making sure no air pockets are present in the cooling system. After the engine cooling system is fully filled up, the radiator cap is placed back on the radiator.




The flush and filtration system of the present invention provides a superior cooling system cleaning by first pre-evacuating the cooling system by applying both pressurized air mixed with the injected liquid, along with a vacuum applied to one or more extraction points of the engine cooling system. This allows the injection of a high speed liquid/air mixture to create a hurricane like effect that removes contaminants hardened to the interior of the cooling system. This hurricane effect is further achieved by using a relatively high amount of air mixed with the injected liquid, along with repeated and relatively short liquid/air injection times, which results in reduced friction and therefore very high speeds of the washing liquid/air combination as it travels through the cooling system. Further, an injection nozzle with a reduced size is used to accelerate the liquid/air wash as it enters the cooling system. The combination of both pressurization at injection and vacuum at extraction reduces the pressurization at the point of injection necessary to create the desired liquid/air wash speed. If a vacuum were not used in conjunction with the pressurization to inject the liquid/air into the cooling system, the hurricane effect could not be achieved without using a level of pressurization that could damage the cooling system itself. The system uses relatively short bursts of liquid/air wash by repeatedly depleting and then replenishing precharge tank


121


, while evacuating the cooling system between each such depletion/replenishment cycle, which maximizes the speed of each subsequent liquid/air injection. The liquid/air injection time length is preferably adjustable from 5 seconds to 20 seconds, which is short enough for high speeds of the liquid/air mixture injections without building up dangerously high pressurizations.




The flush and filtration system


100


also provides a means for conveniently reusing, recycling, and filtering the existing engine coolant, as well as providing a superior means for removing the engine coolant for system cleaning and/or repairs. It also allows the old coolant to be used as the washing/flushing liquid.




A working model of the present invention has been developed with the following specifications:




Power: 115v ac and 12v dc




Air injection pressure: adjustable from 45 psi to 85 psi




Air injection capacity: 150 cf/m with 60 psi pressure




Reserve air tank capacity: 20 gallons




Pre-charge liquid tank capacity: total 1.5 gallons, 0.5 gallons each level, 3 levels




capacity: 185 cf/m air




Sealed pressure of vacuum: 65 inches of water.




Liquid pump: 45 psi auto shut off, 2 gallons per minute




Air/ liquid injection ratio: 0% to 75% adjustable. Superior cleansing occurs starting with air comprising at least 25%, with excellent results with air comprising up to 75% of the liquid/air mixture.




Solenoid valves: orifice size—½ inches (for liquid), ¾ inches (for air and liquid)




Working pressure—300 psi max




Coil voltage—115 vac




Filter capacity: 20 gallons per minute on first stage.




10 gallons per minute on second stage




It is to be understood that the present invention is not limited to the sole embodiment described above and illustrated herein, but encompasses any and all variations falling within the scope of the appended claims. For example, the flush and filtration system will work well for cleaning any type of liquid-based cooling system and for any type of liquid coolant, not just an internal combustion engine cooling system. The flushing coolant and coolant used by the cooling system need not be the same type of liquid. The injection and extraction points of the liquid cooling system used by the present invention are any openings, fittings, connections or coolant lines to which output and vacuum lines or connectors can be attached.




The injection and extraction points illustrated in

FIGS. 25-29

were selected for ease of connection and effectiveness in evacuation of coolant and removal of contaminants, however the location of the injection and/or extraction points and the number of such injection/extraction points can be varied by the user, even for cleaning the same cooling system (i.e. to alternate the flow direction in the cooling system). While air pressure is used in the preferred embodiment to force the coolant from precharge tank


121


into output hose


302


, it is within the scope of the present invention to use a pump similar to pump


103




a


instead. It should be clear that while compressed air and liquid coolant are used with the preferred embodiment, any equivalent gas and any equivalent liquid can be used with, and are within the scope of, the present invention. Lastly, while the use of the precharge tank


121


is preferable because it provides a predetermined amount of liquid for mixture with air and injection into the cooling system, any open or closed loop, internal or external, interrupted or continuous supply of liquid can be used with the present invention (e.g. water faucet, internal or external tanks direct line to vacuum tank


1012


, etc.)



Claims
  • 1. An apparatus for flushing contaminants from an internal combustion engine cooling system that includes a cooling radiator and a heating radiator both connected to an engine block with liquid coolant lines, the flushing apparatus comprising:an injection hose terminating in an injector that is connectable to the engine block to define an injection point into the engine cooling system; an evacuation hose terminating in a connector assembly that is connectable to one of cooling radiator and the heating radiator to define a first extraction point from the engine cooling system; a liquid supply for supplying liquid under pressure to the injection hose and the injection point; a vacuum motor connected to the evacuation hose for applying a vacuum to the evacuation hose and the first extraction point; a gas inlet for receiving compressed gas and for mixing the compressed gas with the liquid supplied by the liquid supply to form a liquid and gas mixture; wherein the liquid and gas mixture enters the engine cooling system at the injection point, travels through the engine block and heating radiator and cooling radiator at a high rate of speed, and is extracted from the engine cooling system at the extraction point by the evacuation hose.
  • 2. The apparatus of claim 1, wherein the gas inlet mixes the compressed gas and the liquid so that the gas forms at least 25% of the liquid and gas mixture.
  • 3. An apparatus for flushing contaminants from an internal combustion engine cooling system that includes a cooling radiator and a heating radiator both connected to an engine block with liquid coolant lines, the flushing apparatus comprising:an injection hose terminating in an injector that is connectable to the engine block to define an injection point into the engine cooling system; an evacuation hose terminating in a connector assembly that is connectable to one of cooling radiator and the heating radiator to define a first extraction point from the engine cooling system; a liquid supply for supplying liquid under pressure to the injection hose and the injection point; a vacuum motor connected to the evacuation hose for applying a vacuum to the evacuation hose and the first extraction point: a gas inlet for receiving compressed gas and for mixing the compressed gas with the liquid supplied by the liquid supply to form a liquid and gas mixture; wherein the liquid and gas mixture enters the engine cooling system at the injection point, travels through the engine block and heating radiator and cooling radiator at a high rate of speed, and is extracted from the engine cooling system at the extraction point by the evacuation hose; and wherein: the liquid supply includes a pre-charge tank for supplying a predetermined amount of the liquid under pressure to the injection hose and the injection point; and the gas inlet includes a pre-charge tank bypass line for receiving compressed gas and mixing the compressed gas with the liquid supplied by the pre-charge tank to form the liquid and gas mixture.
  • 4. The apparatus of claim 3, wherein the vacuum motor includes a vacuum tank for collecting the liquid extracted from the engine cooling system by the evacuation hose.
  • 5. The apparatus of claim 4, further comprising:a supply tank for containing liquid coolant; and a supply tank pump for pumping the liquid coolant from the supply tank to the injection hose.
  • 6. The apparatus of claim 4, wherein the injection hose terminates in an injector nozzle that connects to the injection point of the engine cooling system, and has a reduced diameter relative to a diameter of the injection hose for accelerating the liquid and gas mixture flowing there through.
  • 7. The apparatus of claim 4, wherein the connector assembly is further connectable to the other of the one of cooling radiator and the heating radiator for simultaneously defining a second extraction point from the engine cooling system and for applying a vacuum to both the first and second evacuation points simultaneously.
  • 8. The apparatus of claim 4, wherein the gas inlet is further connected to the pre-charge tank so that compressed gas provides force for the supplying of liquid under pressure from the precharge tank to the injection hose.
  • 9. The apparatus of claim 8, wherein the precharge tank bypass line further comprises a gas bypass valve for adjusting a relative amount of compressed gas that bypasses the pre-charge tank and is mixed with the liquid.
  • 10. The apparatus of claim 9, further comprising:a gas reserve tank connected to the gas inlet, for storing and supplying compressed gas to the precharge tank and the precharge tank bypass line.
  • 11. The apparatus of claim 9, further comprising:a recycle line connected between the vacuum tank and the pre-charge tank; and a recycle pump for selectively pumping liquid,through the recycle line from the vacuum tank to the pre-charge tank.
  • 12. The apparatus of claim 11, further comprising:a filter bypass line connected in parallel to at least part of the recycle line; at least one filter attached to the filter bypass line for filtering any liquid flowing therethrough; and a filter bypass valve for selectively directing liquid flowing in the recycle line to flow through the filter bypass line and the at least one filter.
  • 13. The apparatus of claim 12, further comprising:a gas control valve connected to the gas inlet for selectively cutting off the supply of compressed gas to the precharge tank and the precharge tank bypass line.
  • 14. The apparatus of claim 12, further comprising:a controller for controlling the vacuum motor, the recycle pump, the filter bypass valve and the gas control valve.
  • 15. The apparatus of claim 14, wherein the precharge tank includes a plurality of sensors to detect the level of liquid in the precharge tank, and wherein the controller is responsive to the plurality of sensors to deactivate the recycle pump when the detected liquid level reaches a predetermined value.
  • 16. The apparatus of claim 14, further comprising:a first pressure sensor for measuring the pressure of the liquid and gas mixture in the injection hose, wherein the controller is responsive to the first pressure sensor to deactivate at least one of the vacuum motor, the recycle pump, the filter bypass valve and the gas control valve upon the measurement of pressure that exceeds a predetermined value.
  • 17. The apparatus of claim 16, further comprising:a second pressure sensor attached to the injector nozzle for measuring a pressure of the liquid and gas mixture at the injection point of the coolant circulation system, wherein the controller is responsive to the second pressure sensor to deactivate at least one of the vacuum motor, the recycle pump, the filter bypass valve and the gas control valve upon the measurement of pressure that exceeds a predetermined value.
  • 18. The apparatus of claim 14, wherein the controller:activates the recycle pump for pumping a predetermined amount of liquid from the vacuum tank to the precharge tank; and then deactivates the recycle pump; and then activates the gas control valve for forcing the liquid out of the precharge tank, for mixing the forced liquid from the precharge tank with the compressed gas, and for forcing the liquid and gas mixture into injection hose and into the engine cooling system, and activates the vacuum pump to evacuate the;liquid and gas mixture from the engine cooling system, through the evacuation hose, and into the vacuum tank; and then deactivates the gas control valve and the vacuum pump; wherein said recycle pump activation and deactivation steps, and said gas control valve activation and deactivation steps and said vacuum pump activation and deactivation steps, are repeated a plurality of times.
  • 19. A method of flushing contaminants from an internal combustion engine cooling system that includes a cooling radiator and a heating radiator both connected to an engine block with liquid coolant lines, and points of injection and extraction, the method comprising the steps of:mixing a liquid with a gas to create a liquid/gas mixture; injecting the liquid/gas mixture into an injection point of the engine cooling system under pressure; applying a vacuum to an extraction point of the engine cooling system to evacuate the liquid/gas mixture through the extraction point.
  • 20. A The method of claim 19, wherein the injecting step and applying step are performed simultaneously to create a high speed of flow of the liquid/gas mixture through the engine cooling system.
  • 21. The method of claim 20, wherein the injecting step is performed to the engine block, and the applying step is performed to the cooling radiator.
  • 22. The method of claim 20, wherein the engine cooling system has a plurality of extraction points, and the applying step is performed at the plurality of extraction points simultaneously.
  • 23. The method of claim 22, wherein the injecting step is performed to the engine block, and the applying step is performed to the cooling radiator and the heating radiator simultaneously.
  • 24. The method of claim 20, further comprising the step of:evacuating liquid coolant from the engine cooling system before the injecting and applying steps by injecting a gas into the injection point of the engine cooling system under pressure while simultaneously applying a vacuum to the extraction point of the engine cooling system.
  • 25. The method of claim 20, wherein the mixing step is performed so that the gas forms at least 25% of the liquid/gas mixture.
  • 26. The method of claim 20, further steps of:filtering the evacuated liquid; and repeatedly performing the mixing, injecting and applying steps using the filtered liquid.
Parent Case Info

This application claims the benefit of U.S. Provisional Application No. 60/144,611, filed Jul. 20, 1999, and entitled Injected Liquid Wash in Vacuumed Chambers System.

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4176708 Joffe Dec 1979 A
4178134 Babish et al. Dec 1979 A
4209063 Babish et al. Jun 1980 A
4293031 Babish et al. Oct 1981 A
RE31274 Babish et al. Jun 1983 E
4791890 Miles et al. Dec 1988 A
4793403 Vataru et al. Dec 1988 A
4809769 Vataru et al. Mar 1989 A
4899807 Vataru et al. Feb 1990 A
4901786 Vataru et al. Feb 1990 A
5078866 Filowitz et al. Jan 1992 A
5306430 Dixon et al. Apr 1994 A
5390636 Baylor et al. Feb 1995 A
Provisional Applications (1)
Number Date Country
60/144611 Jul 1999 US