Ratio pump and method

A ratio pump for delivering first and second liquid beverage components in a desired ratio comprising a motor and a pump driven by the motor. The first beverage component is pressurized and is used as the driving fluid for the motor. The second beverage component is pumped by the pump. The first beverage component is exhausted from the motor and delivered along with a second beverage component delivered by the pump. The motor, which may include a piston, requires a predetermined amount of the first beverage component in order to drive the pump to deliver a known volume of the second beverage component.

BACKGROUND OF THE INVENTION 
Many beverages comprise multiple liquid components, such as water and a 
syrup or a concentrate. The water may or may not be carbonated, and the 
syrup may be, for example, a soft drink syrup, and the concentrate may be, 
for example, a fruit juice or tea concentrate. The beverage components are 
typically mixed as the beverage is dispensed at the serving facility. In 
order to have a beverage with the desired taste, it is very important that 
the beverage components be mixed in the correct ratio. 
In a conventional system, the water and syrup or concentrate are provided 
through separate proportioning valves to a dispensing outlet. The valves 
must be initially carefully set to establish the desired ratio and then 
should be re-adjusted daily to maintain the correct ratio. The syrup or 
concentrate is pumped to its proportioning valve by a pump driven by 
carbon dioxide gas. 
This conventional system has experienced numerous problems. For example, 
the valve-adjusting process is time-consuming, and the valve re-adjusting 
process may not be carried out frequently enough to maintain the desired 
ratio. Furthermore, even if the valves are correctly adjusted, pressure 
changes in either of the beverage components furnished to the valves 
results in the dispensing of a beverage having the incorrect ratio of 
components. Also, fibrous concentrates, such as juice concentrates 
containing pulp, tend to foul the concentrate proportioning valve. 
Finally, the pumping of the syrup or concentrate with carbon dioxide gas 
is wasteful in that the gas is exhausted to the atmosphere after it is 
used by the pump. 
SUMMARY OF THE INVENTION 
This invention solves the problems described above with the conventional 
system. Thus, this invention eliminates the proportioning valves of the 
prior art, along with the attendant problems of valve adjustment and valve 
fouling by the concentrate. This invention provides the desired ratio of 
beverage components even if line pressure should vary and does not require 
or waste carbon dioxide gas for the pumping of the concentrate or syrup. 
Although this invention is applicable to the delivery of multiple liquid 
components generally, it is particularly adapted for use with beverage 
components and is described with respect thereto. 
In a typical beverage, the water component is usually supplied at a 
positive pressure. This invention uses the pressurized component, which is 
typically the water component, as the source of power for a motor which 
drives a pump that pumps the other beverage component. After being used as 
the driving fluid, the pressurized component is then exhausted for 
ultimate delivery along with the pumped component for use in the beverage. 
Accordingly, one of the beverage components is used as the source of power 
for pumping the other of the components. 
To assure that the desired ratio is maintained, it is important to employ a 
motor which utilizes a fixed volume of water in causing the pump to pump a 
fixed volume of the pumped component. By so doing, the volume of water 
exhausted from the motor will always bear a predetermined relationship to 
the volume of the pumped component delivered by the pump. 
Although different constructions are possible, the motor can advantageously 
include a motor chamber and a reciprocable member which can be driven 
through strokes of a predetermined length in the motor chamber. Similarly, 
the pump can advantageously include a pumping chamber and a reciprocable 
pumping member which can be driven through strokes of predetermined length 
in the pumping chamber. Accordingly, the ratio of motor exhaust to pump 
delivery will equal the ratio of the areas of the working faces of the 
reciprocable members of the motor and pump, respectively. A fixed ratio of 
the beverage components is delivered even if supply pressures of the 
beverage components to the motor and/or pump should change. 
With this construction, the beverage component ratio is fixed. However, the 
ratio can be changed to a new fixed ratio. This can be accomplished, for 
example, by providing a removable seal gland for sealingly cooperating 
with the reciprocable pumping member. The seal gland and the pumping 
member can then be replaced to provide a pumping member having a larger or 
smaller area to thereby change the ratio. 
The reciprocable members can be of a variety of constructions and may be, 
for example, a diaphragm or piston. However, a piston or other rigid 
member is preferred because it provides greater volumetric accuracy. 
The motor exhaust and the delivery of the pump are fed into a receiver, 
either with the pump itself or downstream thereof, so that the beverage 
components can mix. For example, the receiver may include first and second 
conduits leading, respectively, from the motor exhaust and the pump outlet 
and a common discharge conduit joined to the first and second conduits. 
With this invention, the conduit leading from the pump outlet is devoid of 
any shutoff valve so that it is incapable of shutting off flow of the 
pumped component. This is important as a safety measure to assure that 
this region of the conduit and pump cannot be overpressurized. This is 
particularly important because a typical ratio of the pressurized water to 
concentrate is 5.5 to 1, and accordingly, the concentrate is delivered at, 
in this example, 5.5 times the pressure of the water. It is, therefore, 
desirable to assure that overpressurizing of the pump and its discharge 
line is not likely to occur. 
In a preferred construction, the ratio pump of this invention includes a 
housing, and the reciprocable members of the pump and motor are coaxially 
coupled within the housing. To obtain pump delivery on each stroke of the 
pump, the pump preferably has first and second pumping chambers which are 
preferably located at the opposite ends of the motor chamber and first and 
second plungers coupled to the motor piston for reciprocating within the 
first and second pumping chambers, respectively. 
In order that the reciprocable member of the motor can reciprocate, it is 
necessary to switch the opposite working faces of the reciprocable member 
between an inlet for admitting driving fluid under pressure and an exhaust 
for exhausting the driving fluid under pressure from the chamber. This is 
accomplished by valve means which control the admission and exhaust of the 
liquid component into, and from, the motor chamber, respectively, and 
means for controlling the valve means so that the liquid component can 
reciprocate the reciprocable member. This invention also provides novel 
controlling means which can be used with the ratio pump of this invention, 
or with various reciprocating devices, such as motors and compressors, 
where a switching action of valves is required. 
For example, the controlling means can advantageously include bistable 
spring means for operating the valve means and driving means for driving 
the bistable spring means over center in both directions. The driving 
means may include first and second pivotally mounted levers at opposite 
ends of the motor chamber which are pivotable by the reciprocable member 
as it nears the ends of its strokes to control the valve means. 
The invention, together with additional features and advantages thereof, 
may best be understood by reference to the following description taken in 
connection with the accompanying illustrative drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The drawings show a ratio pump 11 which generally comprises a motor 13 
(FIG. 2) and a pump 15. The ratio pump 11 includes a housing 17 which, in 
this embodiment, includes a central housing section 19 (FIG. 2) and 
identical end housing sections 21 and 21a, all of which are molded of a 
suitable plastic material. The housing sections 19, 21, and 21a are 
suitably interconnected as by threaded fasteners 23 (FIG. 1) and sealed 
together in any suitable manner as by a seal 25. 
As shown in FIG. 1, the housing 17 has a water inlet 27, a water outlet or 
exhaust 29, a syrup inlet 31 and a syrup outlet 33. Of course, the inlets 
27 and 31 and the outlets 29 and 33 can be connected to various different 
liquids. However, in this embodiment, the ratio pump 11 is described with 
reference to ratioing of the beverage components of a beverage which 
comprises a soft drink syrup and a pressurized source of carbonated water. 
If desired, the water can be provided through a valve 35 which 
automatically shuts off when the supply of syrup is exhausted. For 
example, the valve 35 may be a vacuum-operated valve which is coupled to 
the syrup inlet 31 so that it can sense the vacuum pressure that exists 
when the supply of syrup is used up. 
The motor 13 includes a motor chamber or cylinder 37 (FIG. 2) and a 
reciprocable member in the form of a double-acting piston 39 having 
opposed working faces 41 and 43. The piston 39 includes a flange 45 
integral with a plunger 47 of plastic material, a main body or disc 49 and 
a seal 51 molded directly onto the periphery of the disc 49 in a process 
which does not require a separate bonding agent. The disc 49 may be 
threaded onto the flange 45, and the piston 39 and the plunger 47 are 
coaxial. The body 49 and the plunger 47 are constructed of plastic or 
other suitable material. 
In operation, the piston 39 is reciprocated in the cylinder 37 by the 
pressurized carbonated water from the water inlet 27 with each stroke of 
the piston requiring a predetermined volume of the pressurized water. A 
preferred manner of reciprocating the piston 39 is described hereinbelow. 
The pump 15 includes indentical pumping chambers 53 and 53a and a 
reciprocable member in the form of plungers or plunger sections 55 and 55a 
which are reciprocable in the pumping chambers 53 and 53a, respectively. A 
seal gland 57 which includes a relatively rigid ring 59 and a seal 61 
molded directly onto the inner periphery of the ring 59 in a manner that 
does not require the use of a separate bonding agent is removably attached 
in any suitable manner, such as by screws 60 (FIG. 3), to the housing 
section 21 to form an inner end of the pumping chamber 53. An identical 
removable seal gland 57a is provided for the pumping chamber 53a. 
As shown in FIG. 2, syrup is admitted to the pumping chamber 53 on the 
intake stroke, i.e., when the plunger 55 moves to the right as viewed in 
FIG. 2, through an inlet check valve 63 (FIG. 1), which may be of 
conventional construction. Similarly, syrup is discharged from the pumping 
chamber 53 on the discharge stroke, i.e., when the plunger 55 moves to the 
left as viewed in FIG. 2, through an outlet check valve 65. The pumping 
chamber 53a has an inlet check valve (not shown) identical to the inlet 
check valve 63 and an outlet check valve 65a. As shown in FIG. 2, the 
discharge from both of the outlet check valves 65 and 65a is supplied to a 
header 67 which discharges to the syrup outlet 33 as shown in FIG. 2. 
The plungers 55 and 55a, which, in the illustrated embodiment, form 
portions of the plunger 47, have identical working faces 69 and 69a, and 
it is apparent that the volume of syrup pumped by each of the pumping 
chambers 53 and 53a is directly proportional to the areas of the 
associated working face. In this embodiment, the area of each of the 
working faces 41 and 43 of the piston 39 is 5.5 times as great as the area 
of each of the working faces 69 and 69a. Consequently, on each stroke of 
the piston 39, the ratio of water exhausted to syrup pumped will be 5.5 to 
1 as explained more fully hereinbelow. 
Although various different constructions are possible, in this embodiment, 
the working faces 69 and 69a are part-spherical to match part-spherical 
end walls 71 and 71a of the pumping chambers 53 and 53a, respectively. 
Also, the plunger 47 is integrally molded such that the plungers 55 and 
55a are integral with each other and with the flange 45. 
Considering next a preferred manner of using the water under pressure to 
reciprocate the piston 39, the water under pressure from the water inlet 
27 (FIGS. 1 and 5) is directed by valve means 73 (FIG. 5) either to a 
chamber 75 or a chamber 77 (FIGS. 4 and 5) which communicate with the 
working faces 43 and 41, respectively, through identical passages 79 and 
79a formed in the end housing sections 21 and 21a as shown in FIG. 4. The 
valve means 73 is in turn controlled by controlling means 81 (FIGS. 4 and 
5) which is operated by the piston 39. 
More specifically, the valve means 73 includes a linearly movable inlet 
valve element 83, a linearly movable exhaust valve element 85, dual valve 
seats 87 and 89 and dual valve seats 91 and 93 for the inlet and exhaust 
valve elements, respectively, and a connector 95 in the form of a rod for 
joining the valve elements for movement together. The valve elements 83 
and 85 are mounted for movement in valve bodies 97 and 99, respectively, 
which are suitably retained within supporting structure 101 of the central 
housing section 19. 
With the valve means 73 in the position shown in FIG. 5, water at supply 
pressure can flow from the water inlet 27 past the valve seat 87 and 
through the chamber 75 and the passage 79a (FIG. 5) to the working face 43 
to urge the piston 39 to the right as viewed in FIG. 4. In addition, the 
working face 41 communicates with the water outlet 29 through the passage 
79, the chamber 77, the opening of the valve means at the valve seat 93 to 
the water outlet 29. Conversely, with the valve means 73 moved to the left 
from the position shown in FIG. 5, the piston 39 is driven in the other 
direction. 
Generally, the controlling means 81 includes bistable spring means 103 in 
the housing for operating the valve means 73 and driving means which, in 
this embodiment, includes a shaft 105, a collar 107 for driving the 
bistable spring means over center in both directions, and pivotally 
mounted levers 109, 109a, 111 and 111a (FIGS. 3 and 4) at opposite ends of 
the motor cylinder 37 which are pivotable by the piston 39 as it nears the 
ends of its strokes. Although the bistable spring means 103 can take 
different forms, in this embodiment, it includes a hinge member 113 (FIGS. 
4 and 5) having recesses 115 in its opposite faces and an elongated slot 
116 to slidably accommodate the connector 95 with some lost motion, 
longitudinally rigid arms 117 having their inner ends received within the 
recesses 115, respectively, a resilient, channel-shaped bracket 119 
suitably joined to the supporting structure 101 as by screws 121 and 
having outwardly projecting resilient legs 123 with apertures for 
receiving the outer ends of the arms 117, respectively, and springs 125 
urging the legs 123 inwardly and the arms 117 into the recesses 115. As 
best seen in FIG. 6, the arms 117 are bifurcated to provide clearance for 
the valve elements 83 and 85 and the connector 95. The bistable spring 
means 103 is a two-stage device which can be moved from the state shown in 
FIG. 5 over center to a position shown by phantom lines 127 by pushing the 
hinge member 113 to the left as viewed in FIG. 5. Conversely, the bistable 
spring means 103 can be returned to the full-line position for FIG. 5 by 
pushing the hinge member 113 to the right with the shaft 105. 
The levers 109 and 111 (FIGS. 3-5) cooperate to move the collar 107 when 
the piston nears the end of the cylinder 37 occupied by these levers. More 
specifically, each of the levers 109 and 111 is mounted by a resilient pin 
or wireform mounting member 129 attached to the associated end housing 
section 21 and 21a by a suitable fastener 131, with a resilient leg 133 of 
the pin being received in an associated opening located intermediate the 
ends of the associated lever. The levers 109, 109a, 111 and 111a are 
substantially identical, except that the levers 111 and 109a may be 
considered as righthand and the levers 111a and 109 as lefthand. As shown 
in FIG. 4, the lever 111 has a curved surface 135 adjacent to, but 
primarily on one side of, the leg 133. The curved surface 135 bears on a 
planar surface or abutment 137 formed on the housing section 21. One end 
of each of the levers 109-111a has a projection 139 (FIG. 4) engageable 
with the associated working faces 41 and 43. As shown in FIG. 3, the 
projections 139 engage the piston 39 on the opposite sides of the central 
axis 141 of the piston. The opposite ends of the levers 109 and 111 are 
joined together by a pin 143 which extends through tabs 144 (FIG. 3), with 
the major lengths of these levers extending at an acute angle relative to 
the pin axis. The pin 143 for the levers 109 and 111 is covered with the 
collar 107, and the pin 143 for the levers 109a and 111a is covered by a 
collar 107a. 
The shaft 105 is mounted for sliding movement in the supporting structure 
101. The shaft is biased to the left as viewed in FIGS. 4 and 5 by a 
return spring 145 which acts against a retaining ring 147 carried by the 
shaft. The shaft 105 extends completely through the supporting structure 
101, and its opposite ends are engageable with the collar 107a and the 
hinge member 113. Thus, when the piston 39 travels to the extreme right as 
shown in FIG. 4, it will contact the projections 139 of the levers 109 and 
111 and pivot them by causing the curved surfaces 135 to roll on the 
abutments 137 to pivot the levers clockwise as shown in FIG. 4. The 
rolling pivotal movement of the levers 109 and 111 is accommodated by the 
resilience of the wireform mounting members 129 and, in particular, the 
legs 133. Of course, pivoting of the levers 109 and 111 in this fashion 
drives the collar 107 and the hinge member 113 to the left to move the 
bistable spring means 103 over center to the position shown in phantom 
lines 127. Specifically, the connector 95 is engaged by the hinge member 
113 after traveling the full length of the slot 116 to force the valve 
means 73 to its other position to bring about a reversal of the piston 39. 
The action at the opposite end of the cylinder 37 is similar when the 
working face 43 strikes the projection 139 of the levers 109a and 111a to 
pivot these levers in the same manner as described above. In this 
instance, these levers drive the collar 107a and the shaft 105 against the 
biasing action of the spring 145 to cause the shaft to move the hinge 
member 113 through center in the opposite direction back to the position 
shown in FIG. 4. Again, the connector 95 is moved by the hinge member 113 
after the hinge member travels the full length of the slot 116 to switch 
the valve means 73 and reverse the piston 39. 
The water from the water outlet 29 and the syrup from the syrup outlet 33 
can be brought together within the housing 17 or outside of the housing. 
As shown by way of example in FIG. 1, these outlets are brought together 
outside of the housing 17 into a common receiver which includes a water 
conduit 149 leading from the water outlet 29, a syrup conduit 151 leading 
from the syrup outlet 33 and a common discharge conduit 153 which receives 
the delivery from both of the conduits 149 and 151. The dispensing of the 
beverage from the discharge conduit 153 can be controlled by a dispensing 
valve 155. The syrup conduit 151 extends from the syrup outlet 33 all the 
way to the discharge conduit 153, and there is no shutoff valve in the 
conduit 151 or in the pump housing 17 upstream of the conduit 151. 
Accordingly, the conduit 151 and the entire conduit from the there back to 
the outlet check valve 65 is incapable of shutting off flow of the syrup. 
If a valve were provided, for example, in the syrup discharge conduit 151, 
and if that valve were closed while the motor 13 were operating, the much 
higher discharge pressure of the syrup could overpressurize the pump and 
the delivery syrup conduits and bring about a failure. 
The operation of the ratio pump 11 should now be apparent. With the valve 
155 closed, the water exhaust from the motor 13 and the syrup delivery 
from the pump 15 are coupled into the closed conduit 153. Consequently, no 
differential pressure can be developed across the piston 39 and, no 
pumping takes place. However, when a beverage is demanded by opening of 
the valve 155 (FIG. 1), the conduit 153 opens to allow water under 
pressure from the water inlet 27 to drive the piston 39 while the water in 
the cylinder 37 from the previous stroke of the piston 39 is open to 
exhaust across the valve seat 93 to the conduits 149 and 153. Accordingly, 
the piston 39 moves to the left as shown in FIG. 2 and to the right as 
shown in FIG. 4 to exhaust the water in the cylinder 37. In addition, 
syrup previously drawn into the pumping chamber 53 is pumped through the 
outlet check valve 65 and the header 67 to the conduits 151 and 153. 
Simultaneously, movement of the plunger 55a to the left on its intake 
stroke draws syrup from the syrup inlet 31 into the pumping chamber 53a 
through the associated inlet check valve (not shown). 
The volumes of water and syrup delivered are in a ratio established by the 
area of the working face 41 to the area of the working face 69. When the 
piston 39 nears the end of its stroke, its face 41 engages the projections 
139 of the levers 109 and 111 to pivot them as described above to move the 
bistable spring means 103 over center and switch the position of the valve 
means 73. This causes the piston 39 to reverse and to repeat the action 
described above, except that the piston and plunger 47 travel in the 
opposite direction. 
The motor 13 continues to operate for so long as the dispensing valve 155 
is open. Demand operation is achieved without electrical wiring or a 
pressure switch. For example, the volume dispensed in a single stroke may 
be sufficient for a single drink. 
With the construction described above, the beverage component ratio is 
fixed. However, the ratio can be changed to a new fixed ratio by replacing 
the seal glands 57 and 57a and the plunger sections 55 and 55a to provide 
new plunger sections 55 and 55a having a larger or smaller area. 
Although an exemplary embodiment of the invention has been shown and 
described, many changes, modifications and substitutions may be made by 
one having ordinary skill in the art without necessarily departing from 
the spirit and scope of this invention.