U.S. patent number 3,591,051 [Application Number 04/807,494] was granted by the patent office on 1971-07-06 for control to proportion ingredients supplied to drink dispensers.
This patent grant is currently assigned to John E. Mitchell Company. Invention is credited to John D. Harris, Orville Mitchell, Dudley C. Smith.
United States Patent |
3,591,051 |
Mitchell , et al. |
July 6, 1971 |
CONTROL TO PROPORTION INGREDIENTS SUPPLIED TO DRINK DISPENSERS
Abstract
A control for proportioning ingredients supplied to a drink
dispenser. A housing having separate water, syrup and carbon
dioxide chambers. A slide reciprocative within the housing and
having walls defining a wall of each chamber. Reciprocations of the
slide alternately expand and contract the volumes of the chambers
while maintaining desired relative proportions of the water, syrup
and carbon dioxide. Valves operate in response to reciprocation of
the slide to control the introduction of ingredients to and the
discharge from their respective chambers, the slide being
reciprocative in response to alternate introduction of ingredients
to respective chambers.
Inventors: |
Mitchell; Orville (Dallas,
TX), Harris; John D. (Dallas, TX), Smith; Dudley C.
(Dallas, TX) |
Assignee: |
John E. Mitchell Company
(Dallas, TX)
|
Family
ID: |
25196515 |
Appl.
No.: |
04/807,494 |
Filed: |
March 17, 1969 |
Current U.S.
Class: |
222/56;
222/145.1; 200/83J; 200/83A; 222/249; 222/334; 222/145.6 |
Current CPC
Class: |
B67D
1/1288 (20130101); B67D 1/0016 (20130101); B67D
1/0047 (20130101); B67D 2210/00104 (20130101) |
Current International
Class: |
B67D
1/00 (20060101); B67d 005/30 () |
Field of
Search: |
;222/56,361,453,145,249
;200/83 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Coleman; Samuel F.
Assistant Examiner: Stack, Jr.; Norman L.
Claims
What we claim is:
1. A control for supplying ingredients to a drink dispenser the
control comprising a slide housing, a slide reciprocative within
the slide housing, the slide having first, second and third faces,
the first face cooperating with walls of the slide housing to
define a carbon dioxide chamber, the second face cooperating with
walls of the slide housing to define a water chamber, the third
face cooperating with walls of the slide housing to define a syrup
chamber, means to supply carbon dioxide to the carbon dioxide
chamber for driving the slide in one direction of reciprocation,
means to supply water to the water chamber to drive the slide in an
opposite direction of reciprocation, means to deliver carbon
dioxide from the carbon dioxide chamber to the drink dispenser,
means to deliver water from the water chamber to the drink
dispenser means to deliver syrup to the syrup chamber, means to
deliver syrup from the syrup chamber to the drink dispenser, valve
means operable in response to reciprocations of the slide for
blocking the admission of water to the water chamber and unblocking
the delivery of water from the water chamber to the dispenser when
carbon dioxide is admitted to the carbon dioxide chamber and vice
versa, and valve means for blocking the supply of carbon dioxide to
the carbon dioxide chamber and unblocking the delivery of carbon
dioxide from the carbon dioxide chamber to the dispenser when water
is supplied to the water chamber and vice versa.
2. The control of claim 1 with check valves in the syrup-delivering
means to prevent reverse flow of syrup.
3. The control of claim 1 including a diaphragm extending between
the first face of the slide and the slide housing and a diaphragm
extending between the second face of the slide and the slide
housing.
4. The control of claim 1 wherein the maximum volume of the carbon
dioxide chamber is substantially equal to the combined maximum
volumes of the water and syrup chambers, and means to regulate the
supply pressure of carbon dioxide to the carbon dioxide chamber to
about twice the pressure within the dispenser.
5. The control of claim 1 including means to regulate the supply
pressure of carbon dioxide supplied to the carbon dioxide chamber
in predetermined relationship to the pressure in the dispenser and
to the volume of the carbon dioxide relative to the volumes of the
water and syrup chambers.
6. The control of claim 1 including means responsive to movements
of the slide to reverse movement of the slide at each end of
reciprocation thereof.
7. The control of claim 6 wherein the means to reverse movement of
the slide includes a switch actuated by a lever arm, and means on
the slide to move the lever arm.
8. The control of claim 1 wherein the slide comprises first and
second pistons, the first and second faces being on the first
piston and the third face being on the second piston, and means for
mounting the second piston for sliding movement relative to the
first piston.
9. The control of claim 8 including means to adjust the distance of
sliding movement of the second piston relative to the first piston
to adjust the volumetric rate of pumping syrup relative to the
volumetric rate of pumping water.
Description
BRIEF DESCRIPTION OF THE INVENTION
Although this invention may be used to proportion the delivery of
ingredients to any drink dispenser, it is especially suitable for
use with a machine for dispensing semifrozen carbonated drinks or
confections of the kind set forth in Mitchell, et al. application
Ser. No. 770,640, filed Oct. 25, 1968. In this control system, a
slide is reciprocative in a slide housing. The slide has various
piston faces that provide moving walls, one piston face defining a
side of a carbon dioxide chamber, another piston face defining a
side of a water chamber, and a third piston face defining a side of
the syrup chamber. As the slide reciprocates, these piston faces
are moved, thereby varying the volumes of the respective ingredient
chambers. Tubes are provided for delivering carbon dioxide at a
regulated pressure to the carbon dioxide chamber, for delivering
water to the water chamber, and for delivering syrup to the syrup
chamber. Tubes are also provided for discharging carbon dioxide
from the carbon dioxide chamber to a drink dispenser for delivering
water from the water chamber to the drink dispenser, and for
delivering syrup from the syrup chamber to the drink dispenser.
There are solenoid valves appropriately placed in the carbon
dioxide carrying pipes and the water carrying pipes, and there are
check valves in the syrup carrying pipes. Operation of these
solenoid valves is controlled by movements of the slide back and
forth within its housing. Upon actuation of the solenoid valves in
predetermined order responsive to reciprocations of the slide,
carbon dioxide and water are alternately admitted to their
chambers. The supply pressures of the carbon dioxide and water are
greater than the pressure within the dispenser so that the
admission of carbon dioxide forces the slide to move in one
direction whereas the admission of water forces the slide to move
in the opposite direction. As the slide reciprocates, it
alternately sucks syrup into the syrup chamber and drives syrup
from the syrup chamber to the dispenser.
In one embodiment of the illustrated control, the slide is a
two-step piston that establishes the carbon dioxide chamber at an
expanded volume substantially equal to the combined expanded
volumes of the water and syrup chambers. In this embodiment, the
carbon dioxide is admitted to the carbon dioxide chamber at
approximately 2 atmospheres of pressure so that, at atmospheric
pressure, the volume of the compressible carbon dioxide will be
twice the combined volumes of the relatively incompressible water
and syrup. The ratio of syrup to water is controlled primarily by
the relative volumes of the syrup and water chambers, and is finely
adjustable by a suitable regulator.
There is a tube connected from the water source (or it may be
connected from the tube that delivers the combined drink or
confection ingredients to the dispenser) leading to a manually
operable valve. The manually operable valve is located adjacent the
end of the dispenser that delivers drink or confection ingredients
to an outlet faucet. Since the dispenser is of the kind that makes
semifrozen carbonated beverages, there are sometimes small ice
particles or ice jams developed near the outlet faucet. The
manually operable valve is useful to squirt warm water or warm
ingredients into the area where these ice jams occur to melt the
frozen particles.
In a second illustrated embodiment, the slide is a three-step slide
and rolling diaphragms are used instead of O-rings to maintain
fluidtight seals between the water and carbon dioxide chambers. An
O-ring seal is used between the carbon dioxide and syrup chambers,
but since this O-ring seal is on a smaller piston, minimum friction
is produced as the slide reciprocates. In addition, in this
embodiment, the size of the carbon dioxide chamber is reduced
relative to the sizes of the water and syrup chambers to
accommodate higher carbon dioxide pressures and still maintain the
desired ratio of carbon dioxide to liquid at approximately two to
one.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of the control system with the freeze
chamber and syrup tank shown in section.
FIG. 2 is an enlarged sectional view of the control portion of the
system.
FIG. 3 is a schematic diagram of an electric circuit for the
control.
FIG. 4 is an enlarged sectional view of a modification of the
control portion of the system.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, the drink dispenser system 10 has a freeze
chamber 11 to which the control system 12 is connected. The freeze
chamber 11 comprises a cylindrical barrel 13 having endwalls 14 and
15. A cooling coil 16 surrounds the barrel 13 and is connected to a
suitable refrigeration system (not shown) which circulates cooling
fluid through the coil 16 to refrigerate contents within the barrel
13. An agitator shaft 17 is driven by a suitable motor (not shown)
to rotate within suitable bearings 18 and 19 in the end walls 14
and 15. A plurality of agitator and scraper blades 20 are connected
to the shaft 17 to be revolved in close proximity to the inner wall
of the barrel 13 to agitate the contents and scrape any frozen
particles from the wall of the barrel 13.
An outlet passage 23 extends through the lower side of the end wall
15. The passage 23 leads to a chamber 24 within a dispenser faucet
25 of any conventional design that may be actuated, such as by a
knob 26, to permit product to pass from the chamber within the
barrel 13 through the passage 23 to be dispensed from the faucet
25.
An ingredient supply tube 28 extends through the other end wall 14
into communication with the chamber 21. The ingredient supply tube
28 supplies confection or drink ingredients to the chamber 21
according to the demand within the demand within the chamber 21 for
additional ingredients.
Control of the supply of confection or drink ingredients to the
chamber 21 (and control of operation of the refrigeration system to
circulate cooling fluid through the coils 16) may be by any
conventional means. It has been determined that such controls which
are operable in response to variations in pressure within the
chamber 21 are suitable, and controls such as are set forth in
Mitchell, et al., application Ser. No. 770,640, filed Oct. 25,
1968, may be used. As is described in that application, a dual
action pressure switch 29 is mounted in the end wall 14. Switches
30 and 31 (corresponding to the switches 45 and 46 respectively of
the aforesaid Mitchell, et al. application) are actuated in
response to variations in pressure within the chamber 21 to
respectively control the supply of ingredients through the tube 28
to the chamber 21, and to control the circulation of cooling fluid
through the coil 16. The dual action pressure switch is fully
described in the aforesaid Mitchell, et al. application, and for
the purpose of the present invention, it need only be mentioned
that the switch 30 closes to close a circuit 32 (shown in FIG. 3
and to be described hereinafter) when the pressure within the
chamber 21 drops to a predetermined level indicating additional
ingredients should be supplied to the chamber, and the switch 30
opens when the pressure within the chamber 21 rises to a
predetermined level indicating that the chamber 21 is filled to
capacity.
As shown in FIG. 2, the control system 12 has a proportioning
device that comprises a slide housing 34 having a large diameter
cylinder 35 joined by a radial wall 36 to a smaller diameter
cylinder 37. An end wall 38 closes the end of the smaller diameter
cylinder 37. An end wall 38 closes the end of the smaller diameter
cylinder 37. An end wall 39 is connected by suitable bolts 40 to
the opposite end of the large diameter cylinder 35, with an O-ring
41 providing a liquid seal. The large diameter cylinder 35 has a
cylindrical inner wall 42 having an internal diameter of
approximately 11/8 inch. The smaller cylinder 37 has an inner
cylindrical wall 43 having an internal diameter of approximately
one-half inch.
A slide 45 is positioned within the slide housing 34. The slide 45
has larger diameter piston head 46 and a smaller diameter piston
stem 47. The larger diameter piston head 46 has a flat face 48
facing the end wall 39 and an annular flat face 49 facing the
radial wall 36. The surface area of the piston face 48 is
substantially equal to the cross-sectional area defined by the
inner cylindrical wall 42. The area of the piston face 49 is equal
to the area of the piston face 48 minus the cross-sectional area of
the piston stem 47.
The end of the piston stem 47 has a stem face 50. The surface area
of the stem face 50 is substantially equal to the cross-sectional
area defined by the inner cylindrical wall 43 of the smaller
diameter cylinder 37.
The slide 45 is reciprocative within the slide housing 34, with the
piston head 46 being slidable within the larger diameter cylinder
35 and the piston stem 47 being slidable within the smaller
diameter cylinder 37. An O-ring 51 provides a substantially
fluidtight seal between the piston head 46 and the inner
cylindrical wall 42. An O-ring 52 provides a substantially
fluidtight seal between the piston stem 47 and the inner wall 43 of
the smaller diameter cylinder 37. As the slide 45 reciprocates
within the slide housing 34, it varies the volume of a carbon
dioxide chamber 53 that is defined by the inner cylindrical wall
42, the end wall 39 and the moving piston face 48, and it varies
the volume of a water chamber 54 that is defined by the inner
cylindrical wall 42, the radial wall 36, the portion of the stem 47
that projects beyond the radial wall 36, and the moving piston face
50. A syrup chamber 55 of variable volume is defined by the inner
cylindrical wall 43, the end wall 38 and the moving stem face
50.
Carbon dioxide is supplied from a carbon dioxide tank 58 through a
pipe 59 that has a suitable pressure pressure regulator 60
connected in it. There is also a solenoid valve 61 connected in the
pipe 59 to block and unblock the flow of carbon dioxide through the
pipe 59. This solenoid valve 61 is normally closed. Another pipe 62
extends downstream of the solenoid valve 61 through the end wall 39
to communicate with the carbon dioxide chamber 53.
A branch pipe 63 communicates with the pipe 62 and leads to a
normally closed solenoid valve 64. A pipe 65 leads from the
solenoid valve 64 to the ingredient supply tube 28.
Water is supplied from a water source (not shown) through a pipe 68
that leads to a normally closed solenoid valve 69. Another pipe 70
is connected from the solenoid valve 69 through the wall of the
larger diameter cylinder 35 to communicate with the water chamber
54. A pipe 71 branches from the pipe 70 and leads to a normally
closed solenoid valve 72. A pipe 73 leads from the solenoid valve
72 to communicate with the ingredient supply tube 28.
Syrup is supplied from a syrup tank 75 through a dip tube 76. The
dip tube 76 may lead to a manually controllable metering valve 77
for fine adjustments of the rate of flow of syrup, as will be
described, or preferably another kind of syrup volume control as
described in connection with FIG. 4, or any other control may be
used instead of the metering valve 77. A pipe 78 leads from the
metering valve 77 (if there be one) through the wall of the smaller
diameter cylinder 37 into communication with the syrup chamber 55.
There is a check valve 79 in the pipe 78 to permit the flow of
syrup from the syrup tank 75 to the syrup chamber 55, but block
reverse flow of syrup. Another pipe 80 communicates with the syrup
chamber 55 and extends through the sidewall of the smaller diameter
cylinder 37 to communicate with the ingredient supply tube 28.
There is a check valve 81 in the pipe 80 which permits syrup to
flow from the syrup chamber 55 to the ingredient supply tube 28,
but block reverse flow of syrup.
A bracket 84 is connected to the end wall 38 of the slide housing
34. The bracket 84 supports a three-pole double-throw switch 85
having a plunger-type switch actuator 86. The switch actuator 86 is
in constant contact with an inclined surface 87 of an actuator
plate 88. The actuator plate 88 is connected to a rod 89 that
extends through a liquid seal bearing 90 in the end wall 38 and is
threaded into the end of the slide stem 47. When the inclined wall
87 has slid to or beyond the position illustrated in FIGS. 1 and 2
as a result of sliding of the slide 45 to the left, the switch
actuator 86 is depressed to switch the switch 85 to one condition.
When the slide 47 slides to a predetermined position to the right
of the one illustrated, the inclined surface 87 moves to the right
and permits the spring biased actuator 86 to fall to a position at
which it switches the switch 85 to a second switch condition.
FIG. 3 illustrates a circuit 32 that has the switches 30 and 85
connected to operate the solenoid valves 61, 64, 69 and 72. The
switch 30 is connected in one conductor 92 that is connected to one
side of a power supply. Closing of the switch 30 establishes
contact between the conductor 92 and another conductor 93. The
conductor 93 is connected to one pole 94 of the three-pole switch
85. The switch 85 is movable alternately between second and third
poles 95 and 96. A conductor 97 leads from the pole 95 through a
pair of solenoid coils 98 and 99 and thence via a conductor 100 to
the other side of the power supply. The solenoid 98, when
energized, opens the solenoid-controlled valve 61 and the solenoid
99, when energized, opens the solenoid-controlled valve 72. A
conductor 101 is connected from the third switch terminal 96
through a pair of solenoid coils 102 and 103 and thence to contact
with the conductor 100. When the solenoid 102 is energized, it
opens the solenoid-controlled valve 64 and when the solenoid 103 is
energized, it opens the solenoid-controlled valve 69.
A tube 105 branches from the water supply pipe 68 upstream of the
valve 69. The tube 105 leads to a small pushbutton valve 106 that
has an outlet 107 leading to the outlet passage 23 through the end
wall 15 of the freeze barrel 11. Whenever this pushbutton valve 106
is actuated, a squirt of relatively warm water, probably about
70.degree. F. in the summertime and 50.degree. F. in the
wintertime, is squirted into the confection or drink product
adjacent the outlet faucet 25. This pushbutton valve 106 thus
enables hot product to be introduced for melting any ice jams that
sometimes occur at the faucet. These ice jams occur because the
temperature adjacent the faucet is usually the coldest as
distinguished from the temperature adjacent the end wall 14 near
the place where relatively warmer fresh ingredients are being
supplied from the ingredient supply tube 28. Sometimes the ice
particles build up to an ice jam adjacent the faucet 25 and prevent
the dispensing of confection or drink product.
In addition to breaking up the ice jam, the warmer fluid injected
by the pushbutton valve 106 slightly elevates the pressure sure
within the freeze barrel 11. Since the refrigeration system
operates in response to a switch 31 that in turn responds to
pressure within the freeze barrel 11, as described in the aforesaid
Mitchell et al. application, Ser. 770,640, this slight increase in
pressure within the freeze barrel 11 is usually enough to open the
switch 31 and discontinue the circulation of cooling fluid through
the coil 16. As a result, refrigeration of the ingredients within
the chamber 21 is interrupted at a time that helps the operator
break up the ice jam. This system for breaking up the ice jam is
more effective then, and avoids the interruption that otherwise
results from, the standard method of cycling the refrigeration
system to a defrost cycle.
OPERATION
The switch 30 is open so long as the pressure within the chamber 21
is at a high level indicating the chamber 21 is filled to capacity
with confection or drink ingredients. Upon the dispensing of one or
more drinks, the pressure within the chamber 21 drops to a
predetermined lower value, closing the pressure-responsive switch
30. When the switch 30 closes, it closes the circuit to the switch
terminal 94, enabling the switch arm 85 alternately to energize the
solenoid coils 98 and 99 and the solenoid coils 102 and 103.
The switch 85 is controlled by the position of the sliding plate
88. The position of the sliding plate 88 is controlled by the
position of the slide 45. In the position illustrated in FIG. 1,
the slide 45 has slid to or near its maximum left-hand position and
has moved the plate 88 to or near its extreme left-hand position.
In the maximum left position, the inclined surface 87 raises the
actuator 86 sufficiently to actuate the switch 85 to the solid line
position illustrated in FIG. 2. This closes the circuit to the
solenoid coils 98 and 99 leaving the circuit to the solenoid coils
102 and 103 open. When the coils 98 and 99 are thus energized, they
open the valve 61 and 72. With the solenoid coils 102 and 103
deenergized, the valves 64 and 69 remain closed.
Since the valve 61 is open, carbon dioxide flows under the
regulated pressure set by the regulator 60 (approximately 50
p.s.i.) through the pipe 59, the solenoid valve 61 and the pipe 62
to the carbon dioxide chamber 53. Since the solenoid valve 64 is
closed, all the carbon dioxide flowing through the solenoid valve
61 must enter the chamber 53. The pressure of carbon dioxide
against the piston face 48 drives the slide 45 to the left as
viewed in FIG. 1, with the piston face 49 and the stem face 50
expelling water and syrup respectively from the water chamber 54
and the syrup chamber 55. Since the solenoid valve 69 is closed,
the water which flows from the water chamber 54 is driven through
the pipe 71, the solenoid valve 72 (which is open), and the pipe 73
to the ingredient supply pipe 28. Since the check valve 79 prevents
syrup from flowing from the syrup chamber 55 into the pipe 78, the
syrup is driven past the check valve 81 and through the pipe 80, to
the ingredient supply tube 28.
As carbon dioxide continues to flow into the carbon dioxide chamber
53, it continues to drive water and syrup to the ingredient supply
tube 28 until the entering volume of carbon dioxide pushes the
slide 45 to or past the position illustrated in FIG. 1. As the
slide moves to the extreme left-hand position, the plate 88 is
moved to its extreme left-hand position, with the inclined surface
87 pushing the switch actuator 86 upwardly to throw the switch
member 85 from the solid line position to the dotted line position
illustrated in FIG. 2. This energizes the coils 102 and 103 to open
the solenoid-controlled valves 64 and 69 and deenergizes the coils
96 and 97 to close the valves 61 and 72. With the valve 61 closed,
carbon dioxide can no longer flow from the carbon dioxide tank 58
to the carbon dioxide chamber 53, but with the solenoid valve 64
now open, carbon dioxide can flow from the carbon dioxide chamber
53 through the pipe 65 to the ingredient supply tube 28. Likewise,
with the valve 72 closed, water cannot flow through the pipe 73 to
the ingredient supply tube 28. With the valve 69 now open, water at
city water supply pressure, usually between 30 and 80 p.s.i., flows
through the pipe 68, the valve 69 and the pipe 70 to the water
chamber 54. This water being forced into the water chamber 54 acts
against the piston face 49 to drive the slide 45 to the right from
the position illustrated in FIG. 1. As the slide 45 is driven to
the right, the piston face 48 moves to the right to reduce the size
of the carbon dioxide chamber 53 and force carbon dioxide from the
chamber 53 through the pipe 62, the valve 64 and the pipe 65 to the
ingredient supply tube 28. At the same time, the stem face 50 in
moving to the right produces a pressure reduction within the syrup
chamber 55 that sucks syrup through the dip tube 76, the metering
valve 77 (if there be one), the pipe 78 and the check valve 79 into
the syrup chamber 55. This suction pressure within the chamber 55
cannot draw any product from the ingredient supply tube 28 or the
pipe 80 because of the one-way check valve 81. Thus, in this stroke
of the slide 45, water and syrup are being replenished to the water
and syrup chambers 54 and 55, and carbon dioxide is being expelled
from the carbon dioxide chamber 53 to the ingredient supply tube
28.
The ingredients that are forced into the ingredient supply tube 28
flow into the freeze barrel chamber 21. The pressure within the
chamber 21, approximately 20 p.s.i., is below the regulated carbon
dioxide supply pressure and is below the water supply pressure.
It is desirable that the ratio of carbon dioxide to liquid be
approximately 2 to 1 at atmospheric pressure. This ratio is
achieved by supplying the carbon dioxide at a pressure that is
approximately twice atmospheric pressure. Since the carbon dioxide
is a gas and is therefore compressible, carbon dioxide at 2
atmospheres of pressure is compressed within the carbon dioxide
chamber 53 so that when it is released to atmospheric pressure it
would occupy twice the volume of the carbon dioxide chamber 53.
Since the water and syrup are liquids, they are substantially
incompressible when they are admitted to the water and syrup
chambers 54 and 55. Since the volume of the water chamber displaced
by movement of the piston head 46 is a function of the difference
between the cross-sectional area of the larger diameter cylinder 35
and the smaller diameter cylinder 37, and since the volume of the
syrup chamber 55 displaced by the piston stem 47 is a function of
the diameter of the smaller diameter cylinder 37, the combined
volumes of the water chamber 54 and the syrup chamber 55 as
displaced by the slide 47 are equal to the volume of the carbon
dioxide chamber 53 as displaced by the piston head 46. Hence, as
the slide 47 reciprocates through one cycle, it first delivers a
volume of carbon dioxide at 2 atmospheres of pressure from the
chamber 53 to the ingredient supply tube 28 that is equal to the
combined volumes that it next displaces from the water and syrup
chambers 54 and 55 to the ingredient supply tube 28. Since the
carbon dioxide was compressed at 2 atmospheres of pressure within
the chamber 53, approximately twice the volume of carbon dioxide to
liquid is supplied through the ingredient supply tube 28 to the
freeze barrel chamber 21. This volume ratio may be varied by
varying the pressure of the carbon dioxide supplied to the carbon
dioxide chamber 53. This pressure variation is accomplished by
adjusting the regulator 60.
The ratio of syrup to water is also adjustable. The metering valve
77 adjusts the rate of flow of syrup to the syrup chamber 55. If
this metering valve 77 is turned down, there may be a partial
vacuum within the chamber 55 as the slide 45 moves to the right.
This partial vacuum may result in some leakage of water from the
water chamber 54 past the O-ring 52 to the syrup chamber 55 but,
taking such leakage into account, the metering valve 77 may be
adjusted for any desired ratio of syrup to water ultimately
supplied to the ingredient supply tube 28. As already stated, the
control illustrated in FIG. 4 about to be described is preferable
to the metering valve 77 to avoid the aforesaid leakage of
water.
DESCRIPTION OF THE MODIFICATION OF FIG. 4
FIG. 4 illustrates a modified control system 110 that may be used
in place of the control system 12. The control system 110 has a
slide housing 111 comprised of three sections 112, 113 and 114 held
together by suitable bolts (not shown). The slide housing 111 has a
large diameter internal cylinder 115 leading through a step down
cylinder 116 to an intermediate diameter cylinder 117. The
intermediate diameter cylinder 117 is joined by a radial wall 118
to a small diameter cylinder 119. The slide housing section 112 has
an end wall 120 having an inner surface 121. The slide housing
section 114 has an end wall 122 having an internal surface 123. An
access plug 124, provided with an O-ring seal 125, is threaded into
a central opening in the end wall 122.
A slide 126 is slidable within the slide housing 111. The slide 126
comprises a large piston 127 with a smaller piston 128 being
slidably mounted on a stud 129 that projects from the large piston,
as will be described in more detail hereinafter.
The large piston 127 has a face 130 against which the central
portion 131 of a rolling diaphragm 132 is adhered. The outer
periphery 133 of the rolling diaphragm 132 is wrapped about an
O-ring seal 134 that is positioned between the abutting ends of the
slide housing sections 112 and 113. The piston 127 has another face
135 that is annular because of the projecting central stud 129.
Another rolling diaphragm 136 has a central portion 137 adhered to
the piston face 135 and clamped between the pistons 127 and 128.
The outer periphery 138 of the rolling diaphragm 136 is wrapped
about an O-ring 139 that is clamped between the abutting ends of
the slide housing sections 113 and 114.
As mentioned, the small piston 128 is slidably mounted on the stud
129. An O-ring 140 in the stud 129 provides a liquid seal between
the stud 129 and the slidable piston 128. The end of the stud 129
has threads 141, and a nut 142 and locknut 143 are adjustable on
the threads 141 of the stud 129.
The piston 128 has a head 144 on its end with a face 145 directed
toward the end wall surface 123, and an annular face 146 directed
toward the piston face 137. An O-ring 147 provides a fluidtight
seal between the piston head 144 and the inner cylindrical surface
119.
A water chamber 150 of variable volume is defined by the inner
cylindrical wall 115, the end wall surface 121, the face 130 of the
piston 127 (as covered by the central portion 131 of the diaphragm
132, and the rolling portion of the diaphragm surrounding the
piston 127). A port 151 opening through the end wall 120
communicates with the water chamber 150.
A carbon dioxide chamber 152 is defined by the cylindrical wall
117, the radial wall 118, the side of the piston 128, the annular
face 146 of the piston head 144, the face 135 of the piston 127 (as
covered by the central portion 137 of the rolling diaphragm 136,
and the rolled portion of the diaphragm 136 surrounding the piston
127). A port 153 extending through the wall of the housing section
114 communicates with the carbon dioxide chamber 152.
A syrup chamber 154 is defined by the inner cylindrical wall 119,
the face 123 of the end wall 122 (including the inner face of the
plug 124), and the face 145 of the piston 128. An inlet port 155
extends through the wall of the housing section 114 and
communicates with the syrup chamber 154. An outlet port 156 also
extends through the wall of the housing section 114 and also
communicates with the syrup chamber 154.
The pipe 62, which is shown in FIG. 1, is connected to the port 153
in communication with the carbon dioxide chamber 152.
The pipe 78 is connected to the syrup inlet port 155 that
communicates with the syrup chamber 154 (no metering valve 77 is
used), and the pipe 80 is connected with the syrup outlet port 156.
The pipe 70 is connected to the port 151 that communicates with the
water chamber 150. All these pipes 62, 70, 78 and 80 are connected
to the ingredient sources and have the branch pipes and valves that
are illustrated in FIG. 1. Also, the control circuit for the valves
is as illustrated in FIG. 3. The only difference is that the switch
85 is reversed in its operation.
In FIG. 4, this switch 85 is mounted on a bracket 160 that is
connected by suitable means to frame members 161 and 162 mounted on
the slide housing 111. The switch 85 has a depending actuator arm
163 the lower end of which rides in a slot 164 in the piston 127.
The actuator arm 163 extends through a slot 165 in the housing
section 113 so that it is free to pivot as the slide 126
reciprocates. When the slide 126 reciprocates to an extreme
left-hand position, the switch 85 is switched to the dotted line
position illustrated in FIG. 3 to energize the coils 102 and 103
and open the valves 64 and 69. Since the coils 98 and 99 are
deenergized, the valves 61 and 72 remain closed. This condition of
the valves admits water to the water chamber 150 and blocks the
admission of carbon dioxide to the carbon dioxide chamber 152. The
water at between 30 and 80 p.s.i. enters the chamber 150 and drives
the slide 126 to the right, expelling carbon dioxide from the
carbon dioxide chamber 152 and syrup from the syrup chamber 154 as
has been described in connection with the control assembly 12. When
the slide 126 moves to an extreme right-hand condition, the
actuator arm 163 swings to the right and actuates the switch 85 to
the solid line position illustrated in FIG. 2. This closes the
circuit to energize the coils 98 and 99 and opens the circuit to
deenergize the coils 102 and 103. Consequently, the valves 61 and
72 are opened and the valves 64 and 69 are closed. Now, carbon
dioxide is supplied to the carbon dioxide chamber 152 whereas the
supply of water to the water chamber 150 is blocked. As carbon
dioxide is admitted to the carbon dioxide chamber 152, it drives
the slide 126 to the left, expelling water from the water chamber
150 and sucking syrup into the syrup chamber 154. The switch has a
conventional detent (not shown) to hold the arm 163 in either the
solid or dotted position until moved by the external force of
contact with an edge of the slot 164 in the piston 127. Therefore,
the switch 85 is actuated only upon reciprocation of the piston 127
to its extreme left and right positions.
The advantages of the control system 110 are that it reduces the
size of the carbon dioxide chamber 152 relative to the combined
volumes of the water chamber 150 and syrup chamber 154 to
accommodate higher carbon dioxide pressures above 2 atmospheres,
such as pressures in the range of 50 p.s.i.g. Also, the rolling
diaphragms 132 and 138 provide absolute seals against fluid leakage
and at the same time eliminate friction that is caused by O-rings
seals. Since there is an absolute fluid seal produced by the
rolling diaphragms 132 and 138, it is possible to mount the switch
85 as illustrated in FIG. 4 for direct actuation by the contact
between the actuator arm 163 and the V-groove 164.
The sliding piston 128 of FIG. 4 replaces the metering valve 77 of
FIGS. 1 and 2. In FIG. 4, the plug 124 is manually removable to
provide access to the nut 142 and locknut 143. These nuts 142 and
143 can be adjusted to adjust the distance the small piston 129 can
slide on the stud 129, thereby adjusting the net stroke of the
small piston 128. The result is an adjustment of the pumping
capacity of the small piston 129 to adjust the ratio of syrup to
water.
Various changes and modifications may be made within this invention
as will be readily apparent to those skilled in the art. Such
changes and modifications are within the scope and teaching of this
invention as defined by the claims appended hereto.
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