Storage container with an electrically operable circulating pump

A carbonator tank in a post-mix beverage dispenser is provided with an electrically powered circulating pump. The pump is mounted in an opening in the bottom of the tank and includes a flow-through channel for dispensing carbonated liquid from the tank through the housing of the pump. The tank includes a cooling coil for forming an ice bank around the interior walls. The heat generated by the pump motor precludes the freezing of the carbonated water in the flow-through channel.

BACKGROUND OF THE INVENTION 
The present invention relates to a storage container with an electrically 
operable circulating pump, in particular a storage container for 
beverage-vending machines for the storing, carbonation and cooling of 
water which can be discharged through a drain opening located in the base 
of the container. 
A conventional layout of a circulating pump in the carbonating unit of a 
beverage-vending machine is known where cooled and pressurized soda-water 
blended from CO.sub.2 gas and fresh water is stored in the carbonating 
unit acting as a storage container and is available for withdrawal through 
an outflow connection. Here the outlet opening is fitted centrally in the 
base of the storage container with the circulating pump located 
immediately above the outlet opening. 
As a further precaution the circulating pump is affixed to a flow-through 
unit for the soda-water outlet from the storage container. 
Such a layout is employed in conjunction with beverage-vending machines to 
store the cooled and pressurized water enriched with CO.sub.2 gas in order 
to blend it in the desired proportion with separately introduced beverage 
concentrates into a useable beverage. 
In order to ensure a sufficient carbonation of the fresh water in the 
storage container, the carbonation procedures in the storage container 
must be undertaken at increased pressure and backed up by conventional 
procedures for enriching the liquids with CO.sub.2 gas. This can be 
achieved through a circulating pump that draws CO.sub.2 gas from the upper 
region of the storage container and blends it into the water. 
Conventionally such kinds of storage containers are also so cooled in 
their wall regions that an ice layer forms in these regions. This ice 
layer serves as a coolant capacitor. In order that this ice layer should 
form at the walls with an approximately uniform thickness, it is useful, 
if not necessary, to have the water rotate in a circular direction. This 
task is also conventionally allotted to appropriately equipped and located 
circulating pumps. 
For carbonating and circulating the water a suitable motor must be placed 
and affixed in the storage container in which an appropriate means of 
fastening must be provided. 
A drain opening for the desired output of carbonated water must also be 
provided in the vicinity. So as to prevent deterioration in the 
performance of such a layout owing to icing of the drain opening, these 
drain openings are conventionally located below the pump motor. The 
connectors for the motor power supply, however, must also be led out of 
the storage container in the same vicinity. 
SUMMARY OF THE INVENTION 
A primary object of the present invention is directed to the creation of a 
storage container with an electrically operable circulating pump so 
constructed that its cost of manufacture is reduced as far as possible 
while ensuring highly reliable operation. 
A storage container with an electrically operable circulating pump suited 
to fulfill this task is according to the invention specially characterized 
in that a flow-through channel for the water to be dispensed is integrated 
in the housing of a circulating pump in the base of the storage container, 
the housing being led through and affixed to the wall. 
Integrating the flow-through channel for the water to be dispensed in the 
housing of the circulating pump on the one hand presents the risk of icing 
of this channel and on the other eliminates the need for another opening 
in the storage container. The risk of icing is safely eliminated thereby 
since the flow-through channel is adequately warmed even by the small 
amount of heat generated in the pump, especially through rheostatic losses 
in the pump excitation coil. 
The housing of the circulating pump can usually be constructed from 
plastic, so that the flow-through channel can be readily made using 
injection technology. The storage container, if for use in a 
beverage-vending machine as a carbonating unit for the storage of cooled 
and pressurized water enriched with CO.sub.2 gas, is constructed from 
stainless steel so as to comply with the requirements regarding corrosion 
and pressure resistance. Any break through its wall is costly in 
manufacturing terms. Moreover, there is an additional problem with respect 
to sealing due to an additional channel through the wall. 
In a preferred form of construction the arrangement of the storage 
container and the circulating pump is specially characterized in that the 
stationary electromagnetic coil of the pump drive motor is located 
asymmetrically to the side of the latter above a shaft with the rotating 
armature attached to the pump rotor and that the flow-through channel for 
the water to be dispensed passes through the pump housing aligned with the 
rotating armature--pump rotor shaft opposite the excitation coil and in 
the vicinity of the axial line determined by this shaft. 
It is here useful to have the opening for the flow-through channel in the 
base wall of the storage container located asymmetrically with respect to 
the container such that the rotating armature--pump rotor shaft is aligned 
basically with the center of the container. The asymmetrical arrangement 
of the electromagnetic coil of the drive motor with respect to its drive 
shaft and the preferred location of the flow-through channel through the 
pump housing lead to a highly compressed and compact mode of construction 
for the pump. 
At the same time the asymmetrical location of the channel opening in the 
base wall of the storage container is such that the circulating pump and 
the latter's shaft is disposed in the center of the container. This is 
useful because the pump functions to maintain a circular motion of the 
water stored within the container. This should have the effect that the 
ice layer formed as a result of cooling in the boundary regions is as 
cylindrical as possible with respect to its inward-facing wall. Besides 
its function of maintaining the circular flow of stored water, the pump 
also draws CO.sub.2 gas from the upper part of the container into, and 
blends it with, the water. 
In another preferred construction the circulating pump is specially 
characterized in that the pump housing is constructed with walls such that 
a hollow space below and adjoining the exterior of the container is 
provided for the electromagnetic coil and its armature and is separated by 
a dividing wall from a hollow space above, in the interior of the 
container, that is provided for the rotating armature. The wall of the 
pump housing thereby provides a clean, stable separation between the 
interior and exterior of the storage container. Only, the flow-through 
channel penetrates through the wall of the pump housing. Since the space 
for the electromagnetic coil inside the pump housing is constructed with 
an opening to the exterior, the electrical connection cables for the 
electromagnetic coil can also be led out within this open space. The 
electromagnetic field excited by the electromagnetic coil penetrates the 
walls to reach the rotating armature, whose location space is open to the 
interior of the container so that connection to the circulating pump rotor 
can be achieved without additional sealing problems. 
The open space in the pump housing provided for the electromagnetic coil 
is, after introduction of the latter, preferably filled with casting 
resin. 
A through connection is preferably provided from the flow-through channel 
in the pump housing to the rotor area. This through connection from the 
flow-through channel to the rotor area serves in the first place to 
eliminate any dead space within this rotor area in which gas cavities 
could collect. It also serves to enable the water to circulate through 
this rotor area as well, thereby preventing excessive warming there. 
In a further preferred construction according to the invention, the 
arrangement of the storage container with circulating pump is specially 
characterized in that the pump housing, connected to a mounting flange 
that serves as an interior mounting on the container wall, is constructed 
as a support for the flow-through channel through the container wall and 
also provides an external fastening means to the container wall. Here the 
external fasting means is preferably affixed to the support for the 
flow-through channel by means of a bayonet coupling. It will be useful to 
have the external contours of the pump housing, its flange and its 
flow-through channel support constructed symmetrically with respect to 
rotation. 
It is useful to have the flow-through channel emerge from the exterior of 
the pump housing onto a conical support connected to the wall of the pump 
housing, on which support a connecting piece can be mounted. This 
connecting piece can be permanently affixed to the conical support by 
means of the applied casting resin. 
Further scope of applicability of the present invention will become 
apparent from the detailed description given hereinafter. However, it 
should be understood that the detailed description and specific examples, 
while indicating preferred embodiments of the invention, are given by way 
of illustration only, since various changes and modifications within the 
spirit and scope of the invention will become apparent to those skilled in 
the art from this detailed description.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
The storage container as in FIG. 1 comprises a carbonator for 
beverage-vending machines, by means of which carbonated post-mix beverages 
can be blended from carbonated water, prepared by the carbonator and 
beverage concentrates, and offered for consumption. The storage container 
1 is supplied with water through an inlet 2 and with CO.sub.2 gas through 
an inlet 3. The supply of water and CO.sub.2 gas is conventionally 
provided in response to current demand, where the demand for water is 
obtainable through a water-level sensor 4 while the gas supply is 
regulated in accordance with the current internal pressure in the storage 
container 1. Cooling coils 5 are wrapped externally around the storage 
container 1 to apply such a level of cooling to it that an ice layer 6 
forms around the interior walls of the storage container. The thickness of 
this ice layer 6 is monitored through a sensor 7, and cooling via the 
cooling coils 5 is made dependent on the thickness of the layer. Since the 
blend or solution of water and CO.sub.2 gas inside the storage container 
is liquid and forms an ice layer at the side wall regions, the liquid 
portion is cooled to the freezing point just under 0.degree. C. The liquid 
blend inside the storage container is maintained in rotary motion by means 
of a revolving pump rotor 8, so that the ice layer 6 forms in an 
internally cylindrical shape. The circulating pump 9 is, therefore, so 
arranged within the storage container 1 that the pump rotor 8 is disposed 
with its axle approximately concentric with respect to the storage space 
formed by the container walls. By means of a tube 10 extending from the 
pump rotor into the CO.sub.2 gas headspace region, this CO.sub.2 gas is 
drawn down by the pump rotor and blended into the liquid. The circulating 
pump, which is constructed symmetrically with respect to rotation at least 
in its fastening region, possesses a flow-through unit 11, which extends 
through the wall 12 of the storage container 1. The circulating pump is 
supported by a flange 13 on the interior of the wall 12. In the example 
this wall 12 is drawn outward to some extend in the flow-through region. A 
seal ring 14 of elastic material is fitted between the flange 13 of the 
circulating pump 9 and the wall 12 of the storage container 1. By means of 
a bayonet-type coupling a fastening unit 15 is affixed to the flow-through 
channel support 11 of the circulating pump 9 outside the pump wall, so 
that the pump is firmly connected to the storage container 1. 
The carbonated water is dispensed through a drain channel 16 leading to an 
outlet valve that can be constructed in conventional fashion. 
The circulating pump 9 is explained in somewhat greater detail in FIGS. 2 
through 4. In FIG. 3 the drain channel direction is reversed with respect 
to FIG. 1. 
The pump rotor 8 is driven by an electromagnetic motor that consists 
principally of an electromagnetic coil 17 and a rotor 18 made from a 
permanent magnet. This rotor 18 is connected to the pump rotor 8 via a 
hollow shaft 19. This hollow shaft 19 rotates around an axle 20 which is 
mounted vertically on elastic inserts 21 and which preferably and 
conventionally consists of ceramic material for reasons to do with wearing 
and bearing technology. As can be seen from FIGS. 3 and 4, the 
electromagnetic coil 17 is arranged on one side of the rotating armature 
18 and the ferromagnetic poles 22 are set laterally in the region of the 
rotating armature 18. A flow-through channel 23 is integrated in the 
housing of the circulating pump 9 aligned with the axle of the rotating 
armature 18 on the side opposite the electromagnetic coil 17. This 
flow-through channel itself emerges at one end through an opening 24 in 
the interior of the storage container 1 and at the other in the region of 
a support 25 and on to the drain channel 16, FIG. 1 (29 FIGS. 2 to 4). 
The space for the rotating armature formed by the wall 26 of the pump 
housing is open on its underside opposite the flow-through channel 23, so 
that this space can be completely filled by the liquid stored in the 
storage container 1 and also cooled by the liquid flowing through it. 
The wall 26 of the circulating pump 9 is so arranged that it completely 
separates the space provided for the electro-magnetic coil 17 and the 
latter's ferromagnetic poles 22 from the pump areas that are open to the 
interior of the storage container 1. This space provided for the 
electromagnetic coil 17 is, however, open to the exterior of the storage 
container 1. The electromagnetic coil 17 can be inserted and the 
connecting wires 27 led out from this open side. The remaining space 
around the electromagnetic coil 17 can be filled with casting resin 28. 
This casting resin also enables permanent adherence of a connecting piece 
29 mounted on the external conical support 25 of the flow-through channel 
23. 
The invention being thus described, it will be obvious that the same may be 
varied in many ways. Such variations are not to be regarded as a departure 
from the spirit and scope of the invention, and all such modifications as 
would be obvious to one skilled in the art are intended to be included 
within the scope of the following claims.