Information
-
Patent Grant
-
6364545
-
Patent Number
6,364,545
-
Date Filed
Thursday, February 8, 200123 years ago
-
Date Issued
Tuesday, April 2, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 396 626
- 396 636
- 396 578
- 137 386
- 137 391
- 137 406
- 137 523
- 137 56533
- 137 571
-
International Classifications
-
Abstract
A delivery system and method for delivering a processing solution to a processing tank in a processor containing a processing solution. The delivery system is designed to provide a replenishment solution to the processing tank from a package having at least two separate containers. Each of the containers having a processing solution that is to be provided to the at least one processing tank. The delivery system substantially empties each of the at least two separate containers in the package in an accurate predetermined rate so that all of the at least two containers in the package will be substantially empty at the same time. The delivery system includes a mechanism for filling and emptying the predetermined amount of replenishment solution from the retaining vessel in response to the liquid level sensing system.
Description
FIELD OF THE INVENTION
The present invention is directed to photographic processors and more particularly to a replenishment system for accurately delivering replenishment solution from a package containing a plurality of discrete containers to the processing tanks.
BACKGROUND OF THE INVENTION
In many retail establishments there is provided a small mini-lab processor which is used for the processing of film. In such processors, it has been desirable to provide the replenishment solution used for replenishing the processing solutions in the processing tanks to be provided in a combined shipping and dispensing package such as illustrated in U.S. Pat. No. 5,577,614 which is hereby incorporated by reference. This type of package allows a low skill operator of the processing apparatus to quickly and easily provide fresh replenishment solution to the apparatus. Typically, the package has a plurality of individual containers, each having a different processing solution of different amounts that are designed to be emptied all at the same time such that a fresh package can be placed without any waste of processing solution. If too much remaining solution is left in any one of the containers this can present a problem with regard to appropriate disposal of the processing solution remaining therein.
In order to try to improve the emptying of all the containers at the same time, it has been suggested the providing of more accurate feed pumps for delivery of the processing solutions from the package to the processing tanks so that the appropriate amount of processing solution is delivered. While this has provided improvement, this solution is relatively expensive. An additional problem with current processors it that they do not provide any feedback to the operator if there is pump malfunction. The fluid flow or replenishment volume is not measured anywhere in the replenishment delivery system. Typically, the pumps are concealed and the customer has no visual indication of the amount of the replenishment solution delivered. It is assumed that the pumps are always delivering their normal predefined amount. With normal use and wear the pumps will eventually fail without providing a warning to the operator. In addition, there exists the possibility that over time these pumps due to normal wear and tear will eventually fail or become less accurate.
Prior art devices have also suggested various techniques for determining when the containers have been emptied. One such system relies on the placement of a sensor adjacent to the neck of the container and uses this information to determine when the container is empty. Typically, these rely on a collar that is moved in response to the position of the fluid contained therein. When empty, the collar goes to a position that activates the sensor to advise that the container is empty. Occasionally, defects in container manufacturing may cause the floating collar to stick and fail to drop when the package is empty. In other situations, a false empty alarm may be activated due to sensor failure or when the sensors are in need of cleaning or maintenance. An example of use of such sensors are disclosed in U.S. Pat. No. 5,694,991 which is hereby incorporated herein by reference in it's entirety.
The prior art has also disclosed the use of calibrated vessels for metering a desired amount of processing solution in large scale processing system. An example of such units are the Hostert Fotomata Inline/ED 15 replenishment unit found on Model DDP40/120 E6 processor and the Gretag Model E6-120 GL/VESS E-6 processor. These systems are directed to supplying processing solution from a single large supply container into an associated processing tank. These systems are operated in a continuous manner. When the solution in the supply container reaches a low level, a skilled attendant would simply provide more solution to the supply vessel. Packaged chemistry is not suitable for such systems nor is there any concern for associating the refilling of one supply vessel with another supply vessel in these systems.
Thus, there is a need to provide an accurate and economical fluid delivery system for providing replenishment solutions to photographic processors which utilize a replenishment package system having two or more processing solutions that are to be depleted simultaneously.
The present invention provides an accurate delivery system at relatively low costs without the need for expensive metering pumps to dispense the solution and also provides the ability to detect delivery problems in an easier manner than previously allowed. The present invention also provides a delivery system that does not rely on pumps for determining the amount of fluid that has been delivered and once calibrated the amount of solution delivered over time does not change. The present invention further allows a visual indication that a predetermined amount of replenishment solution has been delivered.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention there is provided a photographic processor, comprising:
a processing tank for containing a processing solution through which a media is passed for processing of a media;
a delivery system for providing a replenishment solution to the processing tank from a package having at least two separate containers, each of the containers having a processing solution that is to be provided to the at least one processing tank, the delivery system substantially emptying each of the at least two separate containers in the package in an accurate predetermined rate so that all of the at least two containers in the package will be substantially empty at the same time, the delivery system having a retaining vessel, a liquid level sensing system for sensing a predetermined amount of the replenishment solution in the retaining vessel to be delivered to the processing tank, a delivery mechanism for filling and emptying the predetermined amount of replenishment solution from the retaining vessel in response to the liquid level sensing system.
In accordance with another aspect of the present invention there is provided a method for delivering a replenishment solution to a processing tank in a photographic processor having at least one processing tank and is designed to provide replenishment solution to the at least one processing tank from a package having a plurality of containers each having a processing solution therein, comprising the steps of:
dispensing the processing solutions from each of the containers into an associated retaining vessel until a signal to stop is received; and
dispensing a predetermined amount of the processing solution from the retaining vessel for delivery to one of the processing tanks.
In accordance with yet another aspect of the present invention there is provided a photographic processor, comprising:
a plurality of processing tanks for containing a processing solution through which a media is passed for processing of a media;
a delivery system for providing a replenishment solution to the plurality of processing tanks from a package having at least two separate containers, each of the containers having a processing solution that is to be provided to one of the plurality of processing tanks, the delivery system substantially emptying each of the at least two separate containers in the package in an accurate predetermined rate so that the at least two containers in the package will be substantially empty at the same time, the delivery system having a retaining vessel, a liquid level sensing system for sensing a predetermined amount of the replenishment solution in the retaining vessel, a delivery mechanism for filling and emptying the predetermined amount of replenishment solution from the retaining vessel in response to the liquid level sensing system.
In accordance with still another aspect of the present invention, there is provided a delivery system for providing a replenishment solution to one or more processing tanks from a package having at least two separate containers, each of the containers having a processing solution that is to be provided to the one or more processing tanks, the delivery system substantially emptying each of the at least two separate containers in the package in an accurate predetermined rate so that all of the at least two containers in the package will be substantially empty at the same time, the delivery system having a retaining vessel, a liquid level sensing system for sensing a predetermined amount of the replenishment solution in the retaining vessel to be delivered to the one or more processing tanks, a delivery mechanism for filling and emptying the predetermined amount of replenishment solution from the retaining vessel in response to the liquid level sensing system.
These and other aspects, objects, features, and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the detailed description of the preferred embodiments of the invention presented below, reference is made to the accompanying drawings in which:
FIG. 1
is a diagram representation of the processing apparatus made in accordance with the present invention;
FIG. 2
is a schematic diagram of the delivery system of the apparatus of
FIG. 1
;
FIG. 3
is a schematic diagram of the delivery system for a single container and associated retaining vessel;
FIG. 4
is a schematic diagram of a modified delivery system made in accordance with the present invention;
FIG. 5
illustrates yet another modified delivery system made in accordance with present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to
FIG. 1
there is illustrated an apparatus
10
made in accordance with the present invention. In the particular embodiment illustrated, the apparatus
10
is a stand alone processing apparatus for processing a photosensitive media such as film, paper etc. However, the apparatus
10
may be a part of a larger apparatus such as a mini-lab wherein images are also exposed onto a photosensitive media which is processed in a similar manner.
The apparatus
10
includes a plurality of processing tanks
12
,
14
and
16
each designed to hold a processing solution. A processing path
18
is defined which passes through tanks
12
,
14
and
16
along which a photosensitive media travels for processing of the media, such as photographic film and/or paper. The apparatus
10
also includes a dryer
20
wherein the media is dried. After the media has been dried it is delivered outside of the apparatus
10
through an appropriate outlet
22
as is conventionally done for further treatment (for example, but not limited to scanning, cutting, packaging, etc). In the particular embodiment illustrated, three processing tanks are provided. Processing tank
12
being a developer tank for containing a develop solution; tank
14
being bleach/fix tank for containing a bleach/fix processing solution, and processing tank
16
for holding a wash processing solution. It is of course to be understood that any desired number of processing tanks may be provided containing the appropriate processing solutions as may be required by the photosensitive media being processed.
A computer
24
is provided for controlling operation of the apparatus
10
as is conventionally done. Thus, appropriate computer programs are provided for controlling operations of the various components that are provided in apparatus
10
and for controlling the appropriate sequence of operation of the various components as required for processing the particular photosensitive media being processed. As is typical, the media enters the apparatus through inlet
26
and is transported along the processing path
18
and delivered outside of the apparatus
10
through outlet
22
. The transport mechanism may be of any type suitable for transporting of the media, for example but not by way of limitation, roller assemblies.
The apparatus includes a replenishment and delivery system
30
for providing replenishment solution to each of the tanks
12
,
14
and
16
. In the particular embodiment illustrated, the apparatus is designed to receive a package
32
containing a plurality of individual discrete containers
34
,
36
,
38
and
40
, each containing an appropriate replenishment solution to be used to replenishment the processing solution in each of the processing tanks
12
,
14
and
16
, respectfully. In the particular embodiment illustrated, the containers
34
and
36
are appropriate processing solutions that are to be measured and forwarded to the processing tank
12
whereas the processing solution in container
38
is to be provided to processing container
14
and processing solution in container
40
is to be provided to processing tank
16
. As can be seen, containers
34
,
36
,
38
and
40
each contain a different amount of processing solution. This is because different amounts of processing solution are required for processing a predetermined amount of media that is being processed. Thus, the size and quantity of these processing containers are designed such that when fully empty each will provide the appropriate amount for replenishment of the respective processing solution for processing a predetermined amount of media.
The package
32
is placed on an appropriate support surface
41
Each of the containers
34
,
36
,
38
and
40
is provided with an appropriate valve assembly or connection
42
,
44
,
46
and
48
, respectively, for allowing the processing solution to be emptied from each of the containers. In the particular embodiment illustrated, each container
34
,
36
,
38
, and
40
are appropriately connected by a conduit to respective pumps
50
,
52
,
54
and
56
. Each of the pumps
50
,
52
,
54
and
56
are, through respective appropriate conduits
58
,
60
,
62
and
64
, are fluidly connected to respective retaining vessels
70
,
72
,
74
and
76
which are in turn are fluidly connected to respective pumps
80
,
82
,
84
and
86
. Valves
90
,
92
,
94
and
96
are provided such that one valve is associated with the outlet
71
,
73
,
75
and
77
of each of the retaining vessels
70
,
72
,
74
and
76
, respectively (see FIG.
2
).
Each of the retaining vessels
70
,
72
,
74
and
76
are also provided with an associated sensing system for determining when a predetermined amount of processing solution has been supplied to the retaining vessel for use in controlling the dispensing of a predetermined amount of processing solution from the associated container to its respective associated processing tank.
In the particular embodiments illustrated the sensing system comprises a plurality of sensors associated with each of the retaining vessels
70
,
72
,
74
, and
76
. In particular, three sensors
102
a
,
102
b
,
102
c
102
d
,
104
a
,
104
b
,
104
c
,
104
d
and
106
a
,
106
b
,
106
c
and
106
d
are associated with each of the respective retaining vessels
70
,
72
,
74
and
76
. The subscripts “a, b, c and d” simply identify which of the associate retaining vessels the sensors are associated therewith. For example, subscript “a” indicates the sensors
102
a
,
104
a
, and
106
a
associated with retaining vessels
70
, subscript “b” indicates the sensors
102
b
,
104
b
, and
106
b
are associated with vessel
72
and subscript “c” associates the sensors
102
c
,
104
c
, and
106
c
with retaining vessel
74
and subscript “d” indicates the sensors
102
d
,
104
d
, and
106
d
are associated with retaining vessel
76
. The sensors
102
a-d
;
104
a-d
; and
106
a-d
are all connected by appropriate circuits to computer
24
for the providing of appropriate signals as discussed later herein. In the particular embodiment illustrated, three sensors
102
,
104
, and
106
are provided with respect to each of the retaining vessels
70
,
72
,
74
and
76
. The sensors
102
a-d
is a reference sensor which allows for the operation of the other sensors. The sensors
104
a-d
provide a first reference point and the sensors
106
a-d
are provided at a second reference point.
The replenishment and delivery system
30
for apparatus
10
in the embodiment illustrated in
FIGS. 1 and 2
is made of four separate delivery systems
31
,
33
,
35
, and
37
. Reference is now made to
FIG. 3
where there is illustrated one of the delivery system, in particular delivery system
31
for the associated with a container and the associated processing tank. For ease of understanding, a discussion will be provided with respect to one of the container and its associated processing tank. It being understood that the remaining processing containers and associated tanks operate in a similar manner. In particular,
102
a
is an electrode which can be used for determining the liquid level based on conductivity of the liquid within the retaining vessel
70
. Likewise, the sensor
104
a
is also an electrode that provides a first measuring point
110
. An adjustable electrode
106
a
is provided wherein the end
112
of the electrode provides a second measuring point
114
which defines a predetermined amount of replenishment solution between sensors
104
a
and
106
a
as indicated by the numerals
116
. It is of course to be understood that the size of the retaining vessel and the distance which the sensors
104
a
and
106
a
are spaced apart will provide a predetermined amount of processing solution. In the preferred embodiment, the retaining vessel
70
is provided with calibration indicia so that the amount of liquid between the two sensors
104
a
and
106
a
can be directly read. Appropriate level sensing circuits
120
,
122
are provided for providing information to computer
24
. Initially, the retaining vessel
70
is filled with a predetermined amount of processing solution. This is accomplished by activating pump
50
the processing solution reaches the level indicated by numeral
124
within the container. The pump passes the processing solution through valve
130
. However, valve
130
simply performs the function of allowing fluid flow from the associated container
34
to the retaining vessel
70
. However, the pump
50
itself may serve as a valve. The processing solution is pumped from the container
34
until reaching the appropriate level
124
. In embodiment illustrated the conductivity between the sensors
104
a
and
106
a
provided by the liquid extending between the two electrode produces a signal that advises the computer
24
that the liquid has been provided at the desired level. Once this level is reached, the pump
50
is stopped. When it is desired to deliver processing solution from the retaining vessel
70
to the associated processing tank, pump
51
is activated and it continues until the liquid level falls to the position indicated at point
110
. This produces another signal which is sensed through use of the reference sensor
102
a
and the sensor
104
a
. Thus, based on the conductivity between these two electrodes the computer
24
can determine when the desired amount of processing solution has been provided to the processing tank. Once this has been done, the pump
51
is turned off stopping any further delivery. As can be seen, a precise metered amount will have been delivered to the processing tank. The refilling operation is again conducted as previously discussed by pumping in processing solution by pump
50
until the fluid once again contacts electrode
106
a
. As previously discussed level sensing circuits are provided for determining the appropriate conductivity between the appropriate sensors are reached thus providing the required information to the computer
24
for turning on and off the pumps and valves appropriately. The same procedure is provided for each of the associated containers, retaining vessels and tanks. The use of electrodes provided for precise metering of solution into and out of the retaining vessel
70
on a repeatable basis.
As can be seen, the adjustable sensor
106
can be raised or lowered to provide any desired predetermined amount and rate of dispensing of the processing solution from the container to the associated processing tank. This will of course be dependent upon the type of replenishment solution being supplied and the processing parameters of the processing solution within the processing tank.
Referring to
FIG. 4
, there is illustrated a modified delivery system
126
made in accordance with the present invention with like numerals indicating like parts and operation as previously discussed. In this particular embodiment, gravity is used for dispensing of the replenishment solution from the containers
34
,
36
,
38
and
40
into the processing tanks
12
,
14
and
16
. In this embodiment, only valves
42
,
44
,
46
and
48
are needed to supply processing solution to the retaining vessels as gravity is used to cause fluid to flow from the containers to their respective retaining vessel. Valves
90
,
92
,
94
and
96
control gravity flow from the retaining vessels to the respective tanks
12
,
14
and
16
. The valves need only to be opened and closed as appropriate. The retaining vessels and associated sensors would operate in the same manner except in providing the flow by the pumps. This embodiment provides a less expensive delivery system.
Referring to
FIG. 5
there is illustrated yet another modified delivery system
230
made in accordance with the present invention with like numerals indicated like parts and operation. In this particular embodiment, a single retaining vessel
240
is used in place of all of the retaining vessels
70
,
72
,
74
and
76
previously discussed and a single processing tank
270
is provided in place of the tanks
12
,
14
, and
16
. In this embodiment additional sensors are provided in retaining vessel
240
as required for each of the processing solutions contained therein. Thus, in this embodiment, six sensors would be provided. Sensor
250
a
would be a reference sensor. Sensors
250
b
,
250
c
,
250
d
,
250
e
and
250
f
would each be associated with one of the containers provided. Thus, the sensors
250
b
and
250
c
would be used for providing the amount of processing solution from container
34
whereas sensors
250
c
and
250
d
would provide the appropriate amount of replenishment solution from container
36
, sensors
250
d
and
250
e
would provide the appropriate amount of processing solution from container
38
and sensors
250
e
and
250
f
would provide the appropriate amount of processing solution from container
40
. The positioning of each of these sensors can be adjustable so that the appropriate sensors are engaged for determining the appropriate delivery amount for each of the containers. In this embodiment, the process of replenishment solution from each of the containers
34
,
36
,
38
and
40
would be provided successively in turn as appropriate. Upon completion of providing all the replenishment solution desired then appropriate solution would be delivered to the single processing tank to which it is to be provided for.
In another form of the present invention there is provided means for visually viewing the retained vessels to see if the appropriate amount of processing solution has been delivered. In particular, a window may be provided for viewing only that portion of the retaining vessels that are necessary for viewing of the processing solution contained. The retaining vessels
70
,
72
,
74
, and
76
are provided in an away from the light-tight environment of the processing tanks of the processor. The retaining vessels, as previously discussed can also be provided with calibration marks/indicia
160
for ease of quickly determining the amount of replenishment solution being provided. Also the calibration marks
160
can be used for adjusting the positioning of the appropriate sensors as desired for adjusting the amount of the processing solution to be delivered to the processing tank.
It is to be understood that various changes and modifications may be made. For example, while in the preferred embodiment electrodes are used for sensing of the liquid level, various other types of sensing devices can be used for determining the amount of replenishment solution provided in retaining vessels. For example, ultra sonic sensors could be used for determining the level of the processing solution within the retaining vessel. Any desired number may be provided for determining various different heights within the retaining vessel. If desired, float sensors could be used as an alternative. Any reliable type sensing system may be used for determining when the liquid level in the retaining vessel goes from a first reference point to a second reference point.
It is to be understood that various changes and modifications may be made without departing from the present invention, the present invention being defined by the following claims.
PARTS LIST
10
apparatus
12
processing tank
14
processing tank
16
processing tank
18
processing path
20
dryer
22
outlet
24
computer
26
inlet
30
delivery system
31
delivery system
32
package
34
delivery system
35
container
36
delivery system
37
container
38
delivery system
40
container
41
container
42
support surface
44
connection
46
connection
48
connection
50
connection
51
pump
52
pump
53
pump
54
pump
55
pump
56
pump
57
pump
58
conduit
60
conduit
62
conduit
64
conduit
70
retaining vessel
71
outlet
72
retaining vessel
73
outlet
74
retaining vessel
75
outlet
76
retaining vessel
77
outlet
80
pump
82
pump
84
pump
86
pump
90
valve
92
valve
94
valve
96
valve
102
a-d
sensor
104
a-d
sensor
106
a-d
sensor
110
first measuring point
112
end of electrode
114
second measuring point
116
amount of replenishment solution
120
sensing circuit
122
sensing circuit
124
level indicated within the container
126
modified delivery system
130
valve
160
calibration marks/indicia
230
modified delivery system
240
retaining vessel
270
processing tank
250
a-f
sensor
Claims
- 1. A photographic processor, comprising:a processing tank for containing a processing solution through which a media is passed for processing of a media; a delivery system for providing a replenishment solution to said processing tank from a package having at least two separate containers, each of said containers having a processing solution that is to be provided to said at least one processing tank, said delivery system substantially emptying each of said at least two separate containers in said package in an accurate predetermined rate so that all of said at least two containers in said package will be substantially empty at the same time, said delivery system having a retaining vessel, a liquid level sensing system for sensing a predetermined amount of said replenishment solution in said retaining vessel to be delivered to said processing tank, a delivery mechanism for filling and emptying said predetermined amount of replenishment solution from said retaining vessel in response to said liquid level sensing system.
- 2. A processor according to claim 1 wherein said liquid level sensing system comprises a pair of spaced sensors provided on said retaining vessel.
- 3. A processor according to claim 2 wherein each of said pair of spaced sensors comprises an electrode.
- 4. A processor according to claim 1 wherein said delivery system further comprises a pump associated with said retaining vessel for pumping solution from one of said containers into said retaining vessel.
- 5. A processor according to claim 4 wherein said delivery system further comprises a second pump associated with said retaining vessel for pumping solution from said retaining vessel to said processing tank.
- 6. A processor according to claim 1 wherein each of said processing solutions in each of said containers is to be delivered at a different rate.
- 7. A method for delivering a replenishment solution to a processing tank in a photographic processor having at least one processing tank and designed to provide replenishment solution to said at least one processing tank from a package having a plurality of containers each having a processing solution therein, comprising the steps of:dispensing said processing solutions from each of said containers into an associated retaining vessel until a signal to stop is received; and dispensing a predetennined amount of said processing solution from said retaining vessel for delivery to one of said processing tanks.
- 8. A method according to claim 7 further comprising the step of:successively dispensing processing solutions from at least two of said containers into one of said associated vessels prior to being dispensed to said at least one processing tank.
- 9. A method according to claim 7 wherein a plurality of retaining vessels are provided, each of said retaining vessels being associated with at least one of said containers.
- 10. A photographic processor, comprising:a plurality of processing tanks for containing a processing solution through which a media is passed for processing of a media; a delivery system for providing a replenishment solution to said plurality of processing tanks from a package having at least two separate containers, each of said containers having a processing solution that is to be provided to one said plurality of processing tanks, said delivery system substantially emptying each of said at least two separate containers in said package in an accurate predetermined rate so that said at least two containers in said package will be substantially empty at the same time, said delivery system having a retaining vessel, a liquid level sensing system for sensing a predetermined amount of said replenishment solution in said retaining vessel, a delivery mechanism for filling and emptying said predetermined amount of replenishment solution from said retaining vessel in response to said liquid level sensing system.
- 11. A processor according to claim 10 wherein said liquid level sensing system comprises a pair of spaced sensors provided on said retaining vessel.
- 12. A processor according to claim 11 wherein each of said pair of spaced sensors comprises an electrode.
- 13. A processor according to claim 10 wherein said delivery system further comprises a pump associated with said retaining vessel for pumping solution from one of said containers into said retaining vessel.
- 14. A processor according to claim 13 wherein said delivery system further comprises a second pump associated with said retaining vessel for pumping solution from said retaining vessel to said processing tank.
- 15. A processor according to claim 10 wherein each of said processing solutions in each of said containers is to be delivered at a different rate.
- 16. A processor according to claim 10 wherein said liquid level sensing system comprises a plurality of spaced sensors provided on said retaining vessel such that at least two different processing solutions can be accurately delivered to and from said retaining vessel.
- 17. A delivery system for providing a replenishment solution to one or more processing tanks from a package having at least two separate containers, each of said containers having a processing solution that is to be provided to said one or more processing tanks, said delivery system substantially emptying each of said at least two separate containers in said package in an accurate predetermined rate so that all of said at least two containers into said package will be substantially empty at the same time, said delivery system having a retaining vessel, a liquid level sensing system for sensing a predetermined amount of said replenishment solution in said retaining vessel to be delivered to said one or more processing tanks, a delivery mechanism for filling and emptying said predetermined amount of replenishment solution from said retaining vessel in response to said liquid level sensing system.
- 18. A delivery system according to claim 17 wherein said liquid level sensing system comprises a pair of spaced sensors provided on said retaining vessel.
- 19. A delivery system according to claim 18 wherein each of said pair of spaced sensors comprises an electrode.
- 20. A delivery system according to claim 17 wherein said delivery system further comprises a pump associated with said retaining vessel for pumping solution from one of said containers into said retaining vessel.
- 21. A delivery system according to claim 20 wherein said delivery system further comprises a second pump associated with said retaining vessel for pumping solution from said retaining vessel into said processing tank.
- 22. A delivery system according to claim 17 wherein each of said processing solutions in each of said containers is to be delivered at a different rate.
US Referenced Citations (10)