Method and apparatus for accurately dispensing a solution

Apparatus and a method for dispensing a solution for use in a process including a flow meter and a precision valve are disclosed. A solenoid valve is incorporated within the dispensing apparatus and is electrically connected to the process for preventing flow during process interruption periods. Additional alarm means and safety interlocks are provided for controlling flow based upon operating conditions of the process.

BACKGROUND OF THE INVENTION 
This invention relates to a method and apparatus for regulating the volume 
flow rate of a fluid including a solution. More specifically the invention 
concerns providing apparatus for accurately measuring and controlling the 
rate of flow of a solution and providing solution flow control in response 
to process operation and overflow or underflow conditions. 
In the production of magnet wire an insulation layer is often applied to 
the exterior of the magnet wire such that the wire may subsequently be 
wound into its end use configuration having adjacent turns and layers in 
which the insulation layer providing electrical insulation between 
adjacent turns and layers. In order to provide such a wire it has been 
common to provide a coating having insulating properties which is applied 
to the exterior of the wire. 
Additionally since the magnet wire is wound into a tightly wrapped 
configuration such as an electric motor stator or a solenoid or other 
coil, the wire needs a lubricant on its exterior surface to promote 
handling of the wire while reducing the potential for wire breakage. The 
applicator described herein is capable of both applying a lubricant 
solution to a moving wire as well as applying an insulating coating 
thereto. 
One method of applying either a lubricant or an insulating enamel to magnet 
wire is to have a moving wire pass through a felt applicator. Lubricant or 
enamel is wicked upwardly from a reservoir of solution to the felt 
immediately adjacent the wire and transferred from the felt to the wire to 
apply the coating. The amount of solution supplied by the felt to the wire 
is based on the wicking ability of the felt and the distance between the 
solution and the wire through which the solution must be wicked. The 
height of the reservoir of solution in contact with the felt applicator 
determines the distance between the reservoir of solution and the wire to 
be coated. The distance therebetween controls the amount of solution being 
applied to the wire. Variants in the height level of the solution affects 
the thickness of the coating applied. 
Prior art systems have attempted to regulate the amount of solution 
supplied to the reservoir using an automotive type carburetor. A reduced 
diameter orifice is fed and controlled by a float valve within the 
carburetor. It has been found however that the oscillation and flow from 
the carburetor based upon a control from the float valve is such that the 
height of the reservoir rises and falls creating a variance in the amount 
of solution applied to the exterior surface of the wire. 
Another method of regulating the height of the reservoir is to utilize a 
float valve mounted in the reservoir to travel upwardly and downwardly as 
the height of the reservoir rises and falls. It has been found that such a 
valve lacks the sensitivity needed to accurately control the desired 
height of the reservoir. 
The herein apparatus utilizes a highly sensitive flow meter and a precision 
valve such that the rate of flow of solution may be controlled very 
accurately. In this manner the rate of flow of solution to the reservoir 
is controlled to thereby control the rate of application of the solution 
from the reservoir to the wire. In addition a solenoid valve is provided 
such that flow to the reservoir is interrupted if the wire manufacturing 
process is stopped. In this manner no excess solution is supplied to the 
tank during those intervals when the wire is not being drawn through the 
applicator. Additionally, a float valve is provided as a safety means for 
indicating either high or low levels in the reservoir. This float valve 
may be utilized to deenergize the solenoid preventing further solution 
flow to the reservoir if a high level of solution in the reservoir is 
detected and to energize an alarm of a low level of solution in the 
reservoir is detected. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide apparatus for 
regulating the flow of solution to an applicator. 
It is a further object of the present invention to provide apparatus and a 
method for precisely regulating solution flow to an application process. 
It is still further object of the present invention to provide a method of 
controlling solution flow to an applicator dependent upon the energization 
of a process involving the application of the solution to a moving 
surface. 
It is another object of the present invention to provide safety means for 
interrupting the flow of solution to the applicator upon high liquid level 
conditions being detected. 
It is a yet further object of the present invention to provide an alarm 
indication upon a lack of solution in the reservoir being detected 
indicating a potentially defective product being manufactured. 
It is a further object of the present invention to provide a safe, 
economical, reliable, easy to operate apparatus and method of controlling 
the flow and application of the solution to a moving surface and for 
indicating alarm conditions. 
Other objects will be apparent from the description to follow and the 
appended claims. 
The above objects are achieved according to the preferred embodiment of the 
present invention by the provision of apparatus for regulating solution 
being dispensed to a process use which includes supply means for supplying 
solution, a flow meter for indicating the rate of solution flow through 
the meter, a valve for adjusting the volume flow rate of solution and for 
discharging the solution to the process use. Conduit means are provided to 
serially connect the supply means, the flow meter and the valve in a 
solution circuit such that the valve regulates the flow rate of solution 
which may be modulated based on the flow rate indicated by the flow meter. 
A solenoid valve positioned in the conduit means acts to prevent the flow 
of solution therethrough, said valve acting to allow solution to flow only 
when the process use is consuming solution. 
A method of controlling the amount of solution supplied to an applicator 
which defines a reservoir for supplying the solution to coat a moving 
workpiece is further disclosed. The method includes the steps of supplying 
solution from a source of solution to said reservoir, adjusting the flow 
rate of solution based on the flow rate indicated by a flow rate meter, 
and preventing solution flow to said reservoir when the workpiece is not 
moving.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The herein invention will be described in reference to the embodiment shown 
in the attached drawings. It is to be understood that this invention has 
applicability to other similar applications wherein a liquid is coated on 
a moving surface. Additionally it is to be understood that the specific 
number of wires being simultaneously coated, the specific angles of the 
various slits and the relative locations therebetween are matters of 
choice for a particular application. 
Referring now to FIG. 1 it may be seen that tank 10 contains a quantity of 
a dry lubricant solution referred to as reservoir 59. This solution 
typically includes, a small amount of paraffin wax and/or bee's wax in a 
heptane solvent. When applied to the wire the solvent evaporates leaving 
the wax on the exterior surface of the wire as a dry lubricant. 
Conduit 12 conducts lubricant solution from tank 10 to filter 14. Conduit 
16 conducts the lubricant from filter 14 through pressure gauge 18 to 
conduit 20 to solenoid valve 22. From solenoid valve 22 lubricant flows 
through conduit 24 to flow meter 26 and from there through conduit 28, 
through valve 30, and through conduit 32 to tank 52. Filter 14 is used to 
screen all unwanted particles from the lubricant solution. Pressure 
regulator and gauge 18 is utilized to regulate and determine the pressure 
of the fluid being supplied thereto. If the filter becomes dirty or the 
tank becomes empty the pressure will drop and the operator, by observing 
the pressure indicated by the gauge, will determine that action needs to 
be taken. Solenoid valve 22 is provided to selectively prevent further 
lubricant solution from flowing to tank 52. 
Flow meter 26 is used in combination with precision valve 30 to regulate 
the flow of lubricant solution to the tank. Since the volume of lubricant 
being applied to the wire is small, the flow meter is utilized in 
conjunction with the precision valve to regulate the flow to the tank in a 
precise manner. Additionally by regulating the flow to the tank the level 
within the tank is controlled to obtain the desired wicking effect to 
obtain the desired coating thickness on the wire. Should the level in the 
tank be allowed to rise then the amount of wicking increases dramatically 
and the amount of coating on the wire increases. Again should the level 
drop below a desired level, then the opposite happens and the amount of 
lubricant placed on the exterior surface of the wire is significantly 
reduced. Hence, it is significant that the valve appropriately control the 
desired flow rate as indicated by the flow meter to provide a coating 
level on the wire which is optimal. 
Tank 52 defines a reservoir of solution as indicated. Level gauge 54 is 
mounted at one end of the tank and provides a visual indication of the 
level of the solution in the tank. Float 58 connected to float gauge 60 is 
additionally placed in float pocket 64 of the tank, and, as will be later 
explained, has various electrical connections for indicating certain 
operating conditions. A proximity switch based on photoelectric, inductive 
or capacitive sensing could also be used. Lubricant applicator 50 is 
indicated generically to be the entire assembly of tank 52 containing felt 
applicator 66. Felt applicator 66 is a rectangular planar felt member 
extending in an upright position which may be vertical or inclined within 
the tank such that a bottom or absorption portion 67 of the felt is 
immersed within the solution and a top or application portion 68 of felt 
extends above the solution. Additionally application portion 68 at least 
partially extends above side wall 62 of the tank such that wires 80 may 
extend through the applicator without engaging the tank per se. 
The felt applicator defines an entry slit 70 extending from the top of the 
applicator downwardly at an acute angle to vertical. From the bottom of 
entry slit 70, an angle slit 72 extends upwardly a short distance 
terminating at coating position 82 wherein wire 80 is secured. This 
coating position is located a distance below the top of the felt 
applicator such that the wire is secured therein. Upon an easing of 
tension in the wire, the wire is maintained in the coating position due to 
the geometry of the entry and angle slits and due to the deformation of 
the applicator by the continuous operation of the wire therethrough. In 
the particular applicator shown there are eight sets of entry and angle 
slits designed to act with eight wires being simultaneously lubricated. 
This applicator is designed such that numerous other application 
configurations could be used such as more slits or using only half the 
slits at a time such that on a regular basis the wires could be operated 
through other slits. Additionally absorption portion 67 of the applicator 
may be provided with symmetrical slits such that the applicator may be 
removed from applicator holder 64, inverted and reinserted with the slits 
which were previously immersed in solution now being the slits at the top 
of the applicator such that wire may be inserted therein in the same 
manner as the slits previously described. 
FIG. 2 is a top view of tank 52 of FIG. 1. Therein it may be seen that tank 
52 defines side walls 62. Float 58 of float valve 60 is shown within float 
pocket 64 as is connection 56 for conduit 32 to supply solution to the 
tank. Wires 80 are shown traversing the tank and being located within the 
applicator displaced a distance from that portion where entry slit 70 
terminates at the surface of the felt applicator. 
FIG. 3 is a schematic drawing detailing the manner of operation of a liquid 
application system. In the schematic it may be seen that wire 80 passes 
through felt applicator 66 held by holder 64 and is secured in capstan 
assembly 106. The capstan assembly acts to regulate the speed of the wire 
passing through the applicator. Capstan assembly 106 is powered by capstan 
motor 104. 
Float 58 mounted within tank 52 senses the level of the solution in the 
tank and acts to make electrical connections at float gauge 60. These 
connections are labeled low, C for common, and high such that upon a low 
level of fluid being detected the low connection is energized, and upon a 
high level of fluid being detected the high connection is energized. 
Solenoid valve 22 regulating the flow of lubricant into the tank is also 
shown. 
Power is supplied from lines L1 and L2 through capstan switch 100 and 
through wires 120 and 122 to the capstan motor. Additionally wire 120 
connects the capstan switch to coil 116 for operating capstan relay 
contacts 110 and to low solution indicator 108. Wire 124 connects the low 
level connection of float gauge 60 to low solution indicator 108. Wire 128 
connects the high level position of float gauge 60 to coil 114 for 
operating high solution relay contacts 112. 
Solenoid switch 102 acts to connect line L1 through wire 130, through 
capstan relay contacts 110 if in the closed position, through wire 126, 
through high solution relay contacts 112 if in the closed position and 
through wire 134 to solenoid 22 and to solenoid open indicator 109. wire 
132 connects line L2 to coil 114, to solenoid open indicator 109 and to 
solenoid valve 22. 
To operate the production line producing wire, capstan switch 100 is closed 
energizing capstan motor 104 from lines L1 and L2. At the same time power 
is supplied to the float gauge 60. Float gauge 60 does not act to energize 
either the low level or high level contacts unless the float detects a 
solution level beyond the normal range. Once capstan switch 100 is closed, 
power is additionally supplied through lines 122 and 120 to coil 116 which 
acts to close the capstan relay contacts 110 to allow the solenoid valve 
22 to be opened. Absent capstan switch 100 being in a closed position, the 
solenoid valve may not be operated to allow solution to flow to the tank. 
Hence, upon the production line being shut down by deenergizing the 
capstan switch, the solenoid valve closes thereby preventing further 
solution flow to the tank. 
Should float gauge 60 detect a low solution condition, then low solution 
indicator 108 is energized through wire 124 to indicate to the operator 
that insufficient solution is being supplied to the tank. 
Should float gauge 60 energize the high level solution indicator, then coil 
114 is energized to break the circuit to solenoid valve 22 to prevent 
further solution from being supplied to the tank. The solenoid valve is 
deenergized to prevent further solution being supplied since this solution 
may be highly flammable and spillage conditions are highly undesirable. 
Additionally by limiting the level to which the solution may rise the 
coating of excessive amounts of lubricant on the wires is prevented. 
Solenoid open indicator 109 is a visual indicator (may also be an audible 
alarm) designed to be energized when the solenoid valve is energized 
allowing lubricant flow therethrough. This light is energized whenever the 
solenoid switch is closed, the capstan switch is closed closing capstan 
relay contacts 110 and the high level indicator from the float gauge has 
not been energized. In this mode the solenoid valve is open and the 
solenoid open indicator is energized. Should either the solenoid switch or 
the capstan switch be opened, or the float gauge detect a high level, then 
the solenoid valve will be deenergized and the solenoid open indicator 
will not be energized. 
FIG. 4 is a sectional view of felt sandwich as known in the prior art. The 
wire was placed between two layers of felt, one of which was immersed in a 
liquid solution. The felt would act to wick the liquid solution upwardly 
and apply same to the wire. The felt would additionally act to wick a 
portion of the solution from one piece of felt to the other to provide 
lubricant to both sides of the wire. However as may be seen between upper 
half 92 and lower half 94 of the felt sandwich 90, there is defined a left 
dead space 96 and a right dead space 98. Between these dead spaces it is 
apparent that a significant portion of the wire surface is not in contact 
with the felt and hence does not have lubricant applied directly thereto. 
Additionally the interface between the two separate felt portions affects 
the amount of lubricant being wicked therebetween. 
FIG. 5 is a sectional view of the herein felt applicator. It may be seen 
that wire 80 is secured within coating position 82 at the end of angle 
slit 72. In this position the only dead space is dead space 73 formed 
within angle slit 72 just prior to wire 80. Entry slit 70 and angle slit 
72 are essentially closed except for the dead space immediately adjacent 
the wire. Since the felt applicator is but a single piece the solution may 
be wicked entirely around the wire without having to cross an interface 
between distinct felt portions. In this manner the lubricant may be more 
evenly applied about the entire surface of the wire to effect a more 
uniform coating. 
The invention has been described with reference to a particular embodiment. 
It is to be understood by those skilled in the art that variations and 
modifications can be effected within the spirit and scope of the invention 
.