Single pump recirculating carbonator

A recirculating carbonator and beverage dispenser requires only one pump. The system's function can be enhanced by the use of a two position spool valve having a fresh water inlet port, a carbonated water inlet port, and a fluid outlet port commonly connected with a central bore. A spool member is slidably disposed within the bore to selectively interrupt fluid communication between the carbonated water inlet port and the liquid outlet port during the presence of a low water signal generated by a level sensing device within the system's carbonation tank. During the interruption, fresh make-up water is added to the system.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
In one aspect, this invention relates to carbonator systems. 
In a further aspect, this invention relates to valves which control the 
recirculation of carbonated water within a beverage system and the 
admission of fresh makeup water to the system. 
2. Description of the Prior Art 
Present recirculating carbonator systems constantly draw carbonated water 
from a storage tank, cycle the water past a beverage dispensing head into 
a pump, and return the water to the storage tank in a closed loop. Such 
systems normally use two pumps. One pump is used to recirculate the 
carbonated water throughout the system, and the second pump is used to 
force makeup fresh water into the storage tank for carbonation. The use of 
two pumps adds additional expense and maintenance problems to the present 
recirculating system. 
To overcome this problem, a one pump recirculating system was developed. 
This existing single pump recirculating system utilizes a double diaphragm 
valve which is spring biased to stay in an open position allowing 
recirculation during the normal circulating cycle. The valve is closed by 
means of a fluid amplifier when the liquid level in the storage tank falls 
below a predetermined level. This momentarily stops the carbonated water 
recirculation and the recirculating pump draws fresh water into the system 
through a check valve. The action of the double diaphragm valve is 
dependent upon the use of the fluid amplifier which channels the 
carbonated water recycled into the storage tank into a port which is in 
fluid communication with one side of the diaphragm. 
This system depends on a signal generated by a stream of carbonated water 
directed into an open circuitous passage to activate the diaphragm valve; 
the valve is then rather insensitive to changes in liquid level within the 
storage chamber. Also, the activating force can be affected by the line 
pressure of fresh water to be admitted to the system, such pressures 
having a wide variation on the order of 20 to 60 psi. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a recirculating system which 
is less expensive and more maintenance-free than prior art recirculating 
systems. It is a further object of this invention to provide a system 
which is relatively immune to variations in the water pressure in the 
external water source. A further object is to provide an improved single 
pump recirculating carbonator. 
One feature of this invention is the provision of a two-position spool 
valve within the recirculating carbonated water system. The valve has a 
valve body with a longitudinal bore. A valve outlet in fluid communication 
with the bore recycles carbonated water from the recirculating pipe to a 
storage tank. A recirculating inlet and a fresh water inlet allow water to 
enter the longitudinal bore. A moveable spool is mounted within the bore. 
The spool has a first position which simultaneously maintains the outlet, 
recirculating inlet and fresh water inlet in communication with the bore. 
Since the pressure at the recirculating inlet is higher than the pressure 
at the fresh water inlet, the system recycles carbonated water in the 
first position. When water in the storage tank falls below a predetermined 
level, the spool moves to a second closed position which blocks the 
recirculating inlet. A pump which normally recycles carbonated water will 
draw water from the fresh water inlet through the bore to the outlet and 
pump the fresh water into the storage tank for carbonation and recycling.

DETAILED DESCRIPTION OF THE DRAWING 
Referring initially to FIG. 1 of the drawing, a tank 10 having an inlet 12 
for carbon dioxide is used as a storage tank or reservoir for carbonating 
and storing water. A suitable carbon dioxide source 13 delivers carbon 
dioxide to a check valve 15 from whence it enters tank 10 through inlet 
12. Carbonated water is withdrawn from the lower portion of tank 10 
through a recirculating line 16 which exits tank 10 at outlet 14 and 
thereafter extends past one or more beverage dispensing heads 18. The 
beverage dispensing heads 18, when activated, will draw a quantity of 
carbonated water from the recirculating line 16 via a shunt 20 and 
simultaneously draw a quantity of beverage syrup from an attached syrup 
reservoir 22. The carbonated water is kept constantly circulating in line 
16 at a constant pressure on the order of 80 to 125 psi. If no carbonated 
water is withdrawn by a beverage dispensing head, the carbonated water 
continues through line 16, and passes into the recycling inlet port 26 of 
a spool valve 24. 
From the recycling inlet 26, carbonated water passes through an outlet 28 
and into a pump 30, which acts to draw carbonated water through 
recirculating line 16. The pump 30 discharges the carbonated water from 
the pump outlet into a line 32 and into the storage tank 10. The 
carbonated water reenters the tank through a liquid sensing device 34 
located within the tank. 
It is understood that a cooling mechanism will be used to cool the water at 
some point as it travels through the recycling line 16. Such cooling 
mechanisms and their location are old in the art and form no part of this 
invention. One skilled in the art can easily locate a cooling system which 
will chill the carbonated water to the desired degree and a discussion of 
the chilling system is omitted in the interest of brevity. 
The spool valve 24 of this invention is shown in greater detail in FIGS. 2 
and 3. The valve body is constructed in three parts, a center valve body 
38 and two end caps 40, 42 which are threaded into the center valve body 
to define within the center valve body a shaped longitudinal bore 44. End 
cap 42 defines the recirculating inlet 26. Water from the recirculating 
line 16 enters the shaped longitudinal bore 44 of the valve 24 at the 
recirculating inlet 26. The outlet 28 is disposed in center valve body 38 
and provides an exit path from the bore 44 into the intake of pump 30. 
Liquid entering bore 44 is drawn into the pump and pumped into the storage 
tank 10. Also in fluid communication with bore 44 is a fresh water inlet 
46 defined in center valve body 34 and connected via a double check valve 
48 to supply of city water (not shown). The pressure at the recycling 
inlet 26 normally runs between 80 and 125 psi or higher and the pressure 
at fresh water inlet 46 is normally about 20 to 40 psi. Therefore, when 
both inlets 26, 46 are open to the longitudinal bore 44, the higher 
pressure at the recycling inlet 26 will substantially prevent the influx 
of fresh water through inlet 46 and the valve can be said to be in a 
recycling mode as shown in FIG. 2. 
At the opposite end of the valve body distal the recycling inlet is an 
actuation inlet 50 which is defined by end cap 40 and connected to the 
liquid level sensing means 34 by a line 51 (FIG. 1). A spool assembly 54 
is disposed in bore 44. Assembly 54 includes a main body member 55 and a 
plunger 56. Main body member 55 includes an enlarged end portion 55a 
sealingly and slidably received in end portion 44a of bore 44, a central 
portion 55b slidably and sealingly received in a necked down bore portion 
44b, and an end portion 55c disposed centrally within enlarged bore 
portion 44c. A central bore 57 extends through end portion 55c and 
terminates at a blind end 55d within central portion 55b. Plunger 56 is 
slidably received in bore 57. 
When the liquid level in storage tank 10 falls below a predetermined level, 
valve 24 is actuated by admitting an actuating fluid through the actuation 
inlet 50. The fluid pushes against the large end face 52 of valve assembly 
54 and drives the plunger 56 into a seated or fill mode position as shown 
in FIG. 3. 
Specifically, an annular sealing washer 59 which is positioned on the face 
end of plunger 56 moves into engagement with a valve seat 60 defined at 
the inboard end of recycling inlet 26. This effectively seals the 
recycling inlet 26 from the shaped longitudinal bore 44. In the fill mode, 
the pump 30 withdraws water from the longitudinal bore 44 and creates a 
sufficiently low pressure so that fresh water will enter the longitudinal 
bore 44 through fresh water inlet 46 and thereby the recirculating system. 
Fresh water will continue to enter until the liquid level sensing means 34 
signals that the liquid level in the storage tank has been restored. At 
this point, the actuation is stopped and the pressure which was applied to 
the face 52 of the plunger bleeds through a small bore 62 longitudinally 
disposed through the face of the plunger and exits from the valve body via 
a channel 64. 
The valve spool 54 is shown as being actuated by a fluid applied via the 
actuation port 50. Of course, the valve could be actuated by means of a 
rod or similar well known valve actuation means known in the art. Of 
course, the spool could be actuated by other means. Examples of well known 
mechanical actuation devices are solenoids with push rods. Also mechanical 
or electrical actuation means which move the spool from the recirculating 
position to the fill position and allow return to the recirculating 
position. 
As shown, the annular radially disposed sealing washer 56 is biased into 
engagement with the seat 60 by means of a compression helical spring 66. 
Spring 66 seals at one end on a washer member 65 positioned on plunger 56 
adjacent the inboard end of washer 56; the closed end of spring 66 seals 
adjacent a shoulder 55e defined on main body member 55. This particular 
sealing arrangement provides a means for controlling the water pressure at 
the dispensing head. As the storage tank 10 fills, carbon dioxide within 
the tank will be compressed by the water entering the tank. As the carbon 
dioxide pressure increases, the pressure in the recycling line 16 will 
correspondingly increase and the pressure at the recycling inlet 26 will 
rise to 120 psi or more. The spring 66 allows the annular sealing washer 
56 to slightly disengage from the mating sealing surface 60 allowing a 
small quantity of water to leak into the bore 44 relieving the pressure 
while allowing filling to continue. This feature prevents excessive 
pressure build up in the recirculating line 16 which would affect the 
water to syrup ratio at the dispensing head. The pressure at which the 
spring 66 allows the annular sealing washer to partially release is a 
matter of choice and those skilled in the art can adjust the spring to 
provide the desired pressure in a particular system. 
Referring to FIG. 4, a liquid level sensing device 34 adapted to be used 
with the valve of FIGS. 2 and 3 is shown. The sensing device 34 includes a 
connector 68 having a lower threaded fitting 68a for threaded engagement 
into the inlet of tank 10 and an upper serrated fitting 68b for receipt of 
line 32. A tube 70 is press fit into fitting 68a and extends downward 
therefrom into the storage tank. A plug 71 is fitted into the lower end of 
tube 70 and defines a restricted outlet 74. Recirculating fluid enters the 
bore through inlet 76 and passes through the restricted outlet or orifice 
74 past the mouth 80 of a venturi tube 82. As the recirculating fluid 
passes the venturi tube 82, it creates an area of reduced pressure at the 
mouth 80 of the venturi tube 82. The outer or liquid sensing end 84 of the 
venturi tube contacts the liquid contained within the storage tank. Fluid 
from the reservoir will be drawn through the venturi tube 82 and strike 
the stream of recirculating water as it leaves the restricted outlet 74. 
This deflects the recirculating stream as it passes the mouth 80 of the 
venturi 82. As shown, the liquid drawn through the venturi tube 82 will 
exit from the venturi tube perpendicular to the plane of the drawing and 
will deflect the stream of recirculating fluid exiting from the restricted 
outlet 74 out of the plane of the drawing. 
A cantilevered arm 86 is rigidly mounted at one end 88 to tube 70 of the 
sensor 34 and has a curved end 90 which projects into the straight-line 
path of the recirculating water when there is no water being drawn through 
the venturi pipe 82. A fluid tube 96 extends within tube 70; tube 96 
projects at its upper end through fitting 68b for connection to line 51 
and projects at its lower end through tube 70 for connection with arm 86. 
A sealing pad 92 located on the arm 86 normally blocks the entrance end 94 
of tube 96. In general, the venturi pipe has its lower or terminus end 84 
positioned so that when the storage tank has the desired quantity of 
carbonated water, the terminus end 84 of the pipe 82 is in the carbonated 
water. When the water level falls below the desired level, the terminus 
end of the venturi pipe will be in a carbon dioxide gaseous atmosphere. At 
this point, no liquid will be drawn through the venturi 82 by the 
recirculating water, and the recirculating water will strike the hooked 
end 90 of the cantilevered arm 86. The force of the recirculating water 
striking the arm will deflect the arm and move the pad 92 away from the 
inlet end 94 of the fluid tube 96. The CO.sub.2 gas normally present in 
the storage chamber 10 under pressures of approximately 80 to 120 psi or 
higher will flow freely through the tube 96. Gas exiting from the tube is 
used as a signal warning that the liquid level in the storage tank is 
inadequate. 
In cooperation with the valve disclosed in FIGS. 2 and 3, CO.sub.2 gas will 
be vented directly to the actuation inlet 50 where it will act on the 
plunger 54 moving the valve into the sealing position shown in FIG. 3. 
Of course, various other sensing means well known in the art could be used 
in combination with the valve of this invention. Such mechanical and 
electrical devices create signals which can be used directly to move the 
valve spool or to activate a solenoid or the like. 
Various modifications and alterations of this invention will become obvious 
to those skilled in the art without departing from the scope and spirit of 
this invention. It is to be understood that this invention is not limited 
to the illustrative carbonation embodiment disclosed hereinbefore.