Closed transfer means

A closed transfer apparatus for transferring liquid from a container to a dilution tank in measured volume includes an actuator moveable to a first position that energizes an electric pump to pump liquid from the container into a transfer tank and moveable to a second position which energizes the pump to pump liquid from the transfer tank to the dilution tank; the actuator being biased to a center position in which the electric pump is de-energized and the tanks and the container are all isolated.

This invention relates generally to a means for the closed transfer of a 
liquid concentrate from a small container to a large tank, and more 
particularly, to such a means which is capable of measuring the volume of 
liquid introduced to the tank for proper dilution of the concentrate. 
The handling of chemicals, such as pesticides and fungicides, for example, 
requires care and precision in order to safeguard the health of the 
workers, as well as the environment. In order to apply such chemicals, 
such as to eradicate termites or to protect row crops or groves of trees, 
for example, it is typical to dilute a concentrate of the chemical, which 
is supplied in a returnable sealed container, with water in a large tank 
on a sprayer. The precise ratio of concentrate to water is important so 
that a safe, yet effective, solution is applied to the area being treated 
or to the plants. Measuring the volume of chemical is a critical step in 
the preparation of the proper solution because the chemical represents a 
much smaller volume than that of the water, so a small variation in the 
chemical volume has a disproportionately greater effect on the resulting 
solution than a small variation in the volume of water. Since the solution 
is prepared in the field, the measurement of the chemical volume must be 
accomplished reliably and accurately under a wide range of conditions. The 
transfer must also be accomplished with the least likelihood of spillage, 
including that due to human error, and with minimum exposure to the 
workers and to the environment.

Referring now to FIGS. 1 and 2, there is shown a closed transfer means, 
indicated generally at 10, which includes a base frame 12 with an upright 
support plate 14 attached thereto. A transfer tank 16 is supported on the 
frame 12 and is secured therein by a hold-down bracket (not shown) 
attached to the top of the plate 14. A pump and control means 18 is 
secured to the plate 14 on the side opposite the tank 16. The frame 12 has 
projecting tabs 20 for engagement with complementary slots in a carrier 
(not shown) capable of being mounted in a pick-up truck or other vehicle. 
A bolt or pin extends through a hole 22 in the frame 12 and a 
complementary hole in the carrier to permit ready replacement by securing 
the frame 12, and thus the entire means 10 in the carrier and therefore 
the truck. 
Since the surface on which the truck is resting may not be perfectly 
horizontal, the transfer tank 16 should be capable of accurately measuring 
the volume of liquid therein regardless of the angle at which it may be 
canted from vertical. To achieve this, the sight glass 24 (see FIG.2) is 
positioned on the exterior of the tank, but with the longitudinal 
centerline of the sight glass being on the centroid of the plan form area 
of the tank 16. In this position the sight glass will provide a 
consistently accurate indication of the liquid volume in the tank 
regardless of the orientation of the tank. The upper end of the sight 
glass 24, which is merely a clear glass hollow tube, slideably extends 
through a hole in a boss 26 formed on the tank 16. Packing surrounds the 
tube 24 which is compressed by the end of a fitting 28 threaded into a 
tapped opening in the boss 26. This seals the upper end of the tube 24 
while permitting relative movement between the tube and the tank to 
compensate for the difference in thermal expansion. A vent hole 30 in the 
fitting 28 permits gases to escape from or enter the tank 16, while a 
floating ball 32 carried in a counterbore prevents escape of liquid, as 
would otherwise occur as a result of bouncing during transport, an extreme 
angle from vertical of orientation or when overfilling of the tank 10 is 
attempted. A bore 34 and a cross bore in the fitting 28 permits fluid 
communication between the top of the sight glass and the tank interior. 
The lower end of the tube 24 is sealingly mounted in a boss similar to 
boss 26, and having a fitting similar to fitting 28 but without a vent 30 
and a ball 32 with a bore similar to bore 34 providing fluid communication 
between the tank interior and the lower end of the tube 24. The pumping 
and control unit 18 includes a pair of electrically driven pumps 40 and 42 
having inlets 44 and outlets 46. The pumps are preferably of the type 
which operate at 12 volts so that power can be obtained from the truck 
battery and electrical system. An electrical switch 48 having a plunger 50 
which is depressed to close contacts and activate the pumps 40 and 42 is 
contacted by a cam 52. The cam 52 is simply a V-shaped notch, which notch 
is complementary with the upper end of the plunger 50, extending 
diametrically across a collar 54 secured to the end of a shaft 56 
rotatably mounted in aligned bushings 58 and 60 supported on bracket 62 
secured to the plate 14. An actuating handle or lever 64 is secured to the 
upper end of the shaft 56 so that rotation of the shaft 56 by the lever 64 
will cause the cam 52 to push the plunger 50 downward energizing the pumps 
40 and 42. 
A pair of 4-way valves 70 and 72 are supported on the bracket 62 and have 
their operating stems 74 and 76 respectively inserted into and aligned 
with a sleeve 77. The stems 74 and 76 and the sleeve 77 are cross-drilled 
to accept a stiff U-shaped wire 78 which extends therethrough to couple 
the stems for rotation in unison. A torsion spring 80 is trapped over the 
sleeve 77. The spring 80 has extended ends 82 and 84, the lower end 82 
extending past one side of the stiff wire 78 and a flange 90 mounted on 
the bracket 62 and the upper end 84 extending past the other side of the 
stiff wire 78 and the flange 90. Engaging spur gears 92 and 94 are secured 
respectively to the shaft 56 and to the collar 77. Movement of the handle 
64 to rotate shaft 56 will result in the gears 92 and 94 imparting 
rotation to the sleeve 77, which rotation will be transferred to the stems 
74 and 76. Rotation will also cause the wire 78 to engage one of the 
extended spring ends 82 or 84 while the other spring end will be 
restrained by the flange 90. This will cause the torsion spring 80 to 
"wrap-up", so that upon release of the handle 64, the torsion spring 80 
will return the valves 70 and 72 to a center neutral position, in which 
position all conduit connections to each of the valves 70 and 72 are 
blocked or dead-ended. The gear 94 has a smaller diameter, and thus fewer 
teeth, than the gear 92. As a consequence, the valve stems 74 and 76 will 
rotate a greater amount, i.e., through more degrees of revolution than the 
handle 64 and the shaft 56, which causes the valves 70 and 72 to be opened 
before the switch 48 is closed by the engagement of the plunger 50 with 
the cam 52 and to open the switch 48 turning the pumps off before the 
valves are closed. 
Referring now to FIG. 3, the closed transfer means 10 is shown connected to 
a returnable, sealed container 100, in which the chemical concentrate is 
supplied, and to a dilution tank 102, such as would typically be a 
component part of an agricultural sprayer. To transfer the chemical from 
the container a conduit 104 is connected between the container to the 
valve 70, and to effect transfer of a measured volume of that chemical to 
the dilution tank 102, a conduit 106 is connected between the valve 72 and 
the tank 102. Initial movement of the handle 64 in one direction will 
connect the conduit 104 with the inlets 44 of the pumps 40 and 42 through 
the valve 70 while simultaneously connecting the outlets 46 of the pumps 
40 and 42 with the tank 16. Continued movement of the handle in the same 
direction will cause the cam 50 to depress the plunger 52 a sufficient 
distance to close the switch 48 and activate the pumps 40 and 42. Once the 
contents of the container 100 have been transferred to the tank 16, the 
handle 64 can be moved in the opposite direction which will connect the 
tank 16 with the inlets 44 to the pumps 40 and 42 through valve 70, while 
connecting the outlets 46 of the pumps with the tank 102 through the valve 
72 and conduit 106. The volume of chemical transferred from tank 16 to the 
tank 102 can be conveniently and accurately monitored by the operator 
observing the change in liquid level within the tank 16 as shown in the 
sight glass 24. A transparent cover 108 with appropriate indicia thereon 
mounted on the tank 16 provides both protection for the sight glass and 
means for accurate determination of volume. 
While a preferred embodiment of the present invention has been illustrated 
and described herein, various changes may be made therein without 
departing from the spirit of the invention as defined by the scope of the 
appended claims.