Apparatus for accurately filling beverage cans

Apparatus for filling beverage tanks comprising a liquid manifold and a gas manifold for counter-pressurizing the liquid as it fills the tank. Supply conduits connect the tank with the manifolds. The gas supply conduit contains a coupling device for connection to a fill-height tube on the container. This coupling device includes an optical sensor embodying a prism which reflects light from a light source when the tank has liquid below a predetermined level and directs light onto a photo-conductor. When the liquid reaches a predetermined upper level in the tank and is forced into the coupling device through the fill-height tube, the prism changes its reflective characteristics, and light passes through the prism without reflection. The change in reflective conditions is brought about by the liquid covering adjacent sides of the prism. The photo-conductor correspondingly changes an electrical signal that is utilized to operate a solenoid valve for shutting off the liquid to the tank.

BACKGROUND OF THE INVENTION 
This invention relates to apparatus for filling tanks with soft drink and 
like beverages. More particularly, the invention comprises an arrangement 
for effecting an accurate fill of such tanks. 
Beverage containers or tanks of the type with which the present invention 
is concerned are typically large metal caps which are ultimately used to 
dispense the beverage at refreshment stands and similar locations. The 
tanks may be, for example, of five-gallon (19 liter) capacity which are 
filled with premix or postmix product. When premix is provided, syrup, 
water and carbon dioxide are first mixed in desired proportions, and the 
resultant product is delivered to the tanks. When postmix is provided, 
syrup only is delivered to the tank and the end product is mixed in its 
final form at the dispensing site. 
U.S. Pat. No. 316,098 to Hayden et al. discloses one approach of tank 
handling apparatus, wherein the fluid, whether premix product or postmix 
syrup, is supplied through a manifold and hose or supply line, and carbon 
dioxide is supplied through a gas manifold and hose or supply line. The 
supply lines for the gas and fluid are each attached by suitable fittings 
to the tanks, and the tank is first charged with a quantity of carbon 
dioxide. Thereafter, the liquid is introduced into the tank; the rate of 
tank filling being controlled by the charge of carbon dioxide already in 
the tank. A series of tanks may be serviced at one time. 
During the tank filling process, the carbon dioxide first is introduced 
into the tank through a tube and fitting at or near the tank top. 
Thereafter, the product is introduced through a tube which extends to the 
tank bottom, so that the rising level of liquid in the tank forces some of 
the carbon dioxide out of the tank and back through the carbon dioxide 
supply line. Thus, in order to fill the tank, the pressure of the liquid 
in the liquid supply line is greater than that of the carbon dioxide in 
the tank and in the carbon dioxide supply line. When the tank is filled to 
a predetermined level of liquid, the liquid will enter a fill height tube 
in the top of the rank. This fill height tube communicates with the carbon 
dioxide supply line and, in effect, forms an extension or continuation 
thereof. The rising level of liquid in the fill height tube ultimately 
closes a check valve which is incorporated in a known manner in the 
coupler that connects the carbon dioxide supply tube to the fill height 
tube. 
Upon closing of the check valve, carbon dioxide can no longer escape from 
the carbon dioxide head at the top of the tank. Unless the liquid supply 
is cut off, the liquid will continue to be supplied to the tank until the 
tank is filled or until the pressure head developed by the carbon dioxide 
equals the liquid supply line pressure, and thus becomes sufficient to 
prevent further filling of the tank with liquid. In general, however, a 
result of the foregoing procedure is that the tank sometimes overfilled 
with liquid. In any case, the accuracy of the fill levels obtained by the 
foregoing arrangement is frequently less than what is desired. 
OBJECTS AND SUMMARY OF THE INVENTION 
An object of this inventon is to provide a filling apparatus of the general 
type stated in which a predetermined fill level of liquid in the tank is 
detected by a sensor in the carbon dioxide supply line coupler for the 
tank, whereupon the supply of liquid from the product manifold is quickly 
shut off, thereby insuring that an accurate predetermined amount of premix 
beverage or postmix syrup will then be in the tank. 
A further object of this invention is to provide an apparatus of the type 
stated that utilizes an electro-optical sensor in the gas supply line 
coupler to the tank. The sensor provides a signal to a control circuit 
which, in turn, actuates a solenoid valve to shut off the supply of liquid 
from the supply manifold to the tank. 
In accordance with the foregoing objects, the invention comprises a liquid 
manifold, a gas manifold, a supply conduit connected to each manifold for 
supplying gas and product independently to each container being filled, 
coupler means for connecting each conduit to the container, and a valve in 
the liquid supply conduit for controlling the flow of liquid from the 
liquid manifold to the container. A sensing device in the coupler is 
associated with the gas conduit and operates to sense when the liquid in 
the container reaches a predetermined level of fill. Means responsive to 
the operation of the sensing device, upon said level being reached, closes 
the valve. The sensing device comprises means for changing an electrical 
signal when said level has been reached, and means for utilizing that 
change in electrical signal to effect closing of the valve. 
Also in accordance with the objects, this invention provides a coupler for 
attachment to a beverage container. The coupler embodies a sensor 
comprising a source of light, a photo-responsive device, and a prism 
interposed in the optical path between the source of light and the 
photo-responsive device. In the absence of contact of the prism by liquid 
rising into the coupler from the fill height tube, a relatively large 
amount of light is reflected from the source by the prism to impinge upon 
the photo-responsive device to cause it to respond. Under these 
conditions, the electrical circuitry maintains the liquid fill valve in an 
open condition. However, when liquid contacts and surrounds the prism, 
little light is reflected to the photo-responsive device. This changes the 
electrical signal, and the change in signal is utilized to actuate the 
solenoid valve that controls the liquid supply manifold.

DETAILED DESCRIPTION 
Referring now in more detail to the drawings, FIG. 1 shows a representative 
arrangement for filling containers or tanks 2. In the arrangement shown 
there are a number of tanks 2 which are supported on a skid or pallet 4, 
the pallet or skid 4 being of conventional construction. Above the tops of 
the tanks 2 is a structure 22 that supports a gas manifold 6 for supplying 
carbon dioxide to the tanks 2, and a product manifold 8 for supplying 
liquid such as premix or postmix to the tanks 2. Each tank is connected to 
the manifolds 6 and 8 by flexible supply conduits 10, 12. Conduit 10 is a 
gas supply conduit while conduit 12 is a liquid-product supply conduit. 
The respective conduits 10, 12 may be connected to the manifolds 6, 8 
through conventional couplings devices 14, 16 as shown in FIG. 2, the 
latter including a valve 18 which is operated by a solenoid 20. When the 
valve 18 is closed, the flow of product from the manifold 8 to the conduit 
12 is cut off. The illustrated arrangement for filling a number of 
containers or tanks 2 is merely representative, it being understood that 
the tanks may be handled and filled as a group, or individually, and that 
the manifolds can be arranged or constructed in a number of ways. In the 
illustrated embodiment, the hoses connected to the manifolds 6, 8 may be 
positioned above the structure 22. This structure 22 may be raised and 
lowered by an air cylinder 24 to raise the conduits 10, 12 away from the 
tanks while the pallet is being moved under the manifolds. 
Referring now more particularly, to FIG. 2 it will be seen that the conical 
top wall 25 of the tank 2 has a fill height tube 26 which projects into 
the interior of the tank and also upwardly therefrom above the tank top 
wall. The length of the tube 26 is relatively short. Also mounted in the 
top wall of the tank 2 is a product fill tube 28 which terminates at its 
lower end in closely spaced relationship to the bottom of the tank 2. The 
lower ends of the conduits 10, 12 are provided with coupling devices 30, 
32 which couple onto mating coupling structure at the upper ends of the 
tubes 26, 28. Because the foregoing coupling arrangement is conventional, 
it need not be described in detail. 
Embodied in the coupling device 30 is a sensing device 34 which forms part 
of the present invention, and which is shown in more detail in FIGS. 3 and 
4. This sensing device 34 comprises a housing 36 that defines a tubular 
chamber 38 and which forms part of the flow path of the gas from the gas 
supply manifold 6 to the interior of the tank 2. In the illustrated 
embodiment, the housing 36 also includes a radial tubular extension 40, 
the bore 42 of which is sealed off from the chamber 38 by a prism 44. This 
prism 44 comprises adjacent sides 46, 48 which intersect to form a 
90.degree. angle, and a third side 50 which forms a 45.degree. angle with 
sides 46, 48 and is presented away from the chamber 38 but toward the bore 
42. It will be understood that other arrangements of the housing 36, 
chamber 38 and prism 46 could be provided. 
At its outer end the extension 40 receives a fitting 52 having an opaque 
barrier wall 54 to divide the fittings chamber into adjacent compartments 
56, 58. In the compartment 56 there is a photo-diode 60 or other suitable 
photo-responsive device, while the compartment 58 houses a light-emitting 
diode 62 or like source of light powered from conductors 63. The 
arrangement is such that if sufficient light from the light source 62 
impinges upon the photo-diode 60, an electrical signal will be supplied 
over conductors 64 to an electronic switch/power supply unit 66 (FIG. 2). 
The unit 66 is conventional. 
In use, the conduits 10, 12 are connected through couplers 30, 32 to tubes 
26, 28 of the container or tank 2. Each coupler conventionally has a 
normally closed valve that opens when the coupler is attached and closes 
when the coupler is detached. Similarly functioning valves are in the 
tubes 26, 28. Preferably the conduit 10 is connected first so as to 
counter-pressure the product as it is being supplied through the tube 28. 
In any case, the product rises in the tank 2 until the lower end of the 
fill-height tube 26 is reached. A further rise in liquid level compresses 
the carbon dioxide in the head space above the liquid level and at the 
same time forces liquid into the tube 26 and into the housing chamber 38 
as shown in FIG. 3. 
When the level of the fill liquid 70 is below the prism 44, as shown in 
FIG. 3, light from the diode 62 is reflected by the prism 44 and impinges 
on the photo-diode 60, as indicated by the arrows. The current generated 
by the photo-diode 60 is routed by the conductors 64 to the unit 66. 
However, when the liquid covers the prism surfaces 46, 48 as shown in FIG. 
4, the reflective characteristics of the prism 44 change, and much less of 
the light from the light souce 62 is reflected back to the photo-diode 60. 
Most of the light is refracted and leaves the prism, as indicated. This 
great reduction in sensed light greatly reduces or changes the signal 
transmitted to the discriminator circuit in the unit 66. When the unit 66 
is thus not satisfied, voltage is applied through line 68, and the 
solenoid 20 is closed, thereby closing the valve 18 and immediately 
halting flow of fluid into the tank 2. In this way, the flow of fluid into 
each tank 2 is halted when fluid from that tank rises into the sensor 34. 
If desired, the unit 66 can be provided with an indicator such as a light 
so as to signal the machine operator when all the tanks have been filled