GB2028767A - Metering system for dispensing beer or other potable carbonate liquids - Google Patents
Metering system for dispensing beer or other potable carbonate liquids Download PDFInfo
- Publication number
- GB2028767A GB2028767A GB7922868A GB7922868A GB2028767A GB 2028767 A GB2028767 A GB 2028767A GB 7922868 A GB7922868 A GB 7922868A GB 7922868 A GB7922868 A GB 7922868A GB 2028767 A GB2028767 A GB 2028767A
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- GB
- United Kingdom
- Prior art keywords
- chamber
- liquid
- pump
- metering
- valves
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F11/00—Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid or fluent solid material from a supply or container, without regard to weight, and to deliver it
- G01F11/02—Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid or fluent solid material from a supply or container, without regard to weight, and to deliver it with measuring chambers which expand or contract during measurement
- G01F11/04—Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid or fluent solid material from a supply or container, without regard to weight, and to deliver it with measuring chambers which expand or contract during measurement of the free-piston type
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- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Devices For Dispensing Beverages (AREA)
Abstract
A beer dispensing system comprises a pump having an outlet connected through piping 1, 2, 3, 18, 19 and solenoid valves 4, 5 to a metering cylinder 20 having a piston 21. An electronic controller 22 controls the valves 4, 5 and a shut-off valve 14 in beer outlet piping 8, 9, 12. The controller is operated by a push button switch 32 and by a flow switch 11 in the outlet piping. When the switch 32 is operated the controller 22 sets the valves to cause the pump to dispense a measured quantity of beer through the metering cylinder 20 in which the piston 21 makes one full stroke. The shut-off valve 14 is then closed by the controller and the valves 4, 5 are reset by the controller 22 to cause the piston 21 to make a small return movement. This ensures that the beer in the outlet piping 8, 9, 12 is kept under pressure and fob is prevented from forming in it. <IMAGE>
Description
SPECIFICATION
Metering system for dispensing beer or other potable carbonated liquids
This invention relates to metering systems for dispensing measured volumes of potable carbonated liquids. While such systems can be used for dispensing soft carbonated drinks, their primary purpose is for dispensing beer in public houses and bars and the invention will in general be described in this context.
One kind of system for this purpose comprises a liquid pump having an outlet connected through ducting and electrically operated valves to a metering chamber having a metering member which is freely movable to and fro in the chamber, liquid outlet ducting connected through further electrically operated valves to the chamber and leading to a liquid dispensing outlet fitted with an electrically operated shut-off valve, an electronic controller which controls the valves and the pump and is connected to the flow switch, and a manuallyoperated switch for setting the system in operation to dispense a measured volume of liquid.The valves and the pump are so controlled by the controller that, upon one operation of the manually-operated switch, liquid is pumped into the chamber on one side of the metering member to cause the member to move in one direction to dispense a measured volume of liquid from the chamber on the other side of the member and, upon a further operation of the manually-operated switch, liquid is pumped into the chamber on the other side of the member to cause the member to move in an opposite direction to dispense a measured volume of liquid from the chamber on the one side of the member.
With existing systems of this kind, atthe end of a liquid dispensing operation in which for example one half pint of beer is dispensed, the metering member is in a limiting position at one end of its to and fro movement. When the manually-operated switch is actuated, the controller sets the valves in such a way that the pump is connected to the chamber on one side of the metering member and the outlet ducting is connected to the chamber on the other side of the metering member. Further, the shut-off valve is opened and the pump is set in operation so that beer or other liquid is supplied under pressure to the chamber on the one side of the member and this causes the member to be moved to its other limiting position at the other end of its to and fro movement.The movement of the metering member causes beer or other liquid already in the chamber on the other side of the member to be dispensed through the outlet opening. As soon as dispensing starts, the flow through the outlet ducting operates the flow switch and this causes the pump to remain in operation until the metering
member reaches its other limiting position thus ensuring that a volume of beer or other liquid is dispensed equal to the whole swept volume of the
metering member. This swept volume is the measured volume, for example one half pint, which the system is constructed to dispense.
The electronic controller includes a memory circuit so connected that when the manually-operated switch is next actuated, the electrically operated valves are actuated in such a way that the pump is connected to the chamber on the other side of the metering member and the outlet ducting is connected to the chamber on the one side of the metering member. A further cycle of operations then takes place with the metering member moving back from its other end position to its one end position in the chamber to dispense a further measured volume of liquid.
In these existing systems, when the pump stops at the end of a dispensing operation, the beer or other carbonated liquid between the pump and the chamber is maintained under pressure generated by the pump, but it is also desirable to keep the liquid in the outlet ducting under a pressure which is at all times above the carbonation equilibrium pressure so that carbon dioxide is prevented from being expelled from the beer or other liquid and thus the formation of fob in the outlet ducting is avoided. This ensures, when beer is being dispensed, that a well presented measure of beer flows from the dispensing outlet into a glass. This is important not only from the point of view of appeal to the customer, but also to ensure that the glass will hold the measured quantity of beer together with a small head that may be produced as the beer flows into the glass.
In the past it has been the practice to fit a restriction in the outlet ducting close to the dispensing outlet and this ensures that the pressure in the beer or other liquid in the outlet ducting remains acceptably high during dispensing. However when the metering member reaches one of its limiting end positions, the pump pressure is no longer transmitted to the beer or other liquid downstream of the metering member and as a result the pressure in the outlet ducting will fall. The rate of fall of the pressure is a function of the area of the restriction and of the compressability of the carbonated liquid. The system is maintained in operation by the flow switch and it is impossible for the controller to shut the shut-off valve at the dispensing outlet until flow has ceased and the flow switch has been actuated.If the controller were able to shut the shut-off valve before the metering member reached the end of its movement in one direction or the other, a short measure would be dispensed. However the flow switch and the controller take a finite time to operate and shut the shut-off valve and during this time the fall in pressure in the outlet ducting is appreciable.
When such a system is used for dispensing lager or other highly carbonated beers, the fall in pressure in the outlet ducting before the shut-off valve is closed can present a serious problem because the pressure is below the carbonation equilibrium pressure and therefore substantial fobbing takes place in the outlet ducting.
This problem is at present partly overcome by fitting long lenths of restrictor piping adjacent the dispensing outlet to slow down the pressure decay until the flow switch can operate and the shut-off valve is closed. The presence of this restrictor piping is not entirely effective and it further has the undesirable effect of slowing down the dispensing time, sometimes causing it to take over 20 seconds for a half pint measure to be dispensed.
Systems of the kind described have now been used for dispensing lager and other highly carbonated beers for some years and yet the problem of fobbing in the beer outlet ducting has not previously been overcome.
According to this invention, the controller in a liquid metering system of the kind described is so constructed that it operates the valves and the pump in a sequence such that when the metering member reaches the end of its movement in one direction and flow through the outlet ducting ceases, the flow switch is actuated to cause the shut-off valve to be closed and then the valves are operated to cause the pump to be connected to the chamber on the other side of the metering member and the outlet ducting to be connected to the chamber on the one side of the metering chamber before the pump is stopped, whereby the pump applies pressure through the metering member to the liquid in the outlet ducting and this pressure is maintained owing to the prior closure of the shut-off valve.
With the system constructed so that the valves and the pump are operated by the controller in this way, there will be a fall in the pressure of the lager or beer in the outlet ducting after the metering member has reached the end of its movement in the one direction and before the shut-off valve has closed. However this fall in pressure is of no consequence because the pressure is immediately restored again by the pressure from the pump acting upon the metering member and tending to move the metering member in a return direction away from its position at the end of its movement in the one direction. Even if the momentary fall in pressure in the outlet ducting allows the production of a small amount of fob, this fob is driven back into solution as the lager or beer in the outlet ducting is re-pressurised.
If any fob has been produced in the beer outlet ducting, a return movement of the metering member will be necessary to re-pressurise the lager or beer in the outlet ducting, but this movement will be very small. Further, the total volume of the system downstream of the metering member when the metering member is at the end of the movement in one direction remains unaltered and as the shut-off valve has closed before any return movement of the metering member takes place, the volume metered by each stroke of the metering member from one end position to the other end position remains unaltered and equal to the total swept volume of the metering member.
Preferably the chamber is a cylinder and the metering member is a piston which reciprocates between one end of the cylinder and the other end and in this case the outlet of the beer pump is connected through the ducting and electrically operated valves selectively to both ends of the cylinder and the beer outlet ducting is similarly connected to further valves. Alternatively, however, the metering member may be a diaphragm which extends across a chamber which in this case is preferably spherical or in the case where the metering member is a piston and the chamber is a cylinder, all the ducting connections may be made to one end of the cylinder and flow to the cylinder on the side of the piston remote from the end of the cylinder which the ducting is connected, takes place through a hollow fixed piston rod around which the piston fits and along which the piston slides.
Preferably the controller is constructed so that the pump is kept in operation for approximately one second after the shut-off valve is closed and the valves have been operated to cause the pump to be connected to the chamber on the other side of the metering member and the outlet ducting to be connected to the chamber on the one side of the metering chamber. During this time, the pump, which as usual is not of the positive displacement type, only displaces a very small volume of lager or beer sufficient to produce the re-pressurisation of the lager or beer in the outlet ducting and the whole system is then pressurised by the pump to the pump lock-off pressure.
The construction of the system in accordance with the invention calls only for a modification of the construction of the controller and this is a simple matter which can readily be achieved by designers of such electronic controllers. The present invention lies in the entirely novel concept of causing the pump to re-pressurise the beer or carbonated liquid downstream of the metering member after the shut-off valve has closed, instead of trying to prevent the pressure of this liquid from decaying before the shut-off valve has closed.
In spite of its apparent simplicity, the present invention has been found to overcome the problem of fobbing of lager and other highly cabonated beers when these are dispensed through systems of the kind described. This problem has existed for some years and the present invention fulfils a very real need which has not previously been satisfied in spite of attempts to do so.
An example of a metering system in accordance with the invention will now be described with reference to the accompanying drawing which is a diagram showing both the liquid and electrical connections of the system with the electrically operated shut-off valve and the further electrically operated valves shown in greater detail, but still diagrammatically.
In the example illustrated, which is of a system for dispensing measured volumes of beer from a dispenser on a bar, an electrically driven centrifugal pump, which is not shown, has its inlet connected to a beer keg, which is also not shown and is pressurised with carbon dioxide, and its outlet connected to a pipe 1. The pipe 1 leads through two further pipes 2 and 3 to two three-way solenoid valves 4 and 5 respectively. The solenoid valves 4 and 5 have outlets 6 and 7 which are connected by pipes 8 and 9 respectively and a common pipe 10 to a flow-switch 11 The flow switch 11 is connected by a pipe 12 to the inlet 13 of a solenoid-operated shut-off valve 14 having an outlet 15 which forms a beer dispensing nozzle at a bar.
Thevalves 4 and 5 havefurther ports 16 and 17 respectively, which form both inlets and outlets and
which are connected by pipes 18 and 19 respectively
to the two ends of a metering cylinder 20 containing
a piston 21 which forms a metering member.
An electronic controller 22 is connected by elec
trical leads 23 and 24 to coils 25 and 26 of the
solenoid valves 4 and 5 respectively.
The controller 22 is also connected by leads
indicated at 27 to the motor of the centrifugal pump;
by leads 28 to the flow switch 11; by leads 29 to a coil
30 of the solenoid valve 14; by leads 31 to a
manually-operated push-button dispense switch 32
and by leads 33 to an indicator lamp 34.
At the start of a cycle of operations by which the
metering system dispenses a measured quantity of
beer, the piston 21 is very close to one end or the
other of the measuring cylinder 20. In a cycle which
starts when the piston 21 is at the bottom of the
measuring cylinder 20, the coil 25 of the valve 4 is
de-energised and a closure member 35 of the valve
is held by a spring 36 in the position shown in the
drawing in which the outlet 6 is closed and the inlet
pipe 2 is connected to the pipe 18 and hence to the
bottom of the cylinder 20.
The controller 22 energises the coil 26 of the valve
5 so that a closure member 37 of the valve 5 is held
against the action of the spring 38 in a bottom
position in which it closes the pipe 3 leading from
the pump to the valve 5 and puts the port 7 in
communication with the port 17 so that the pipe 19 is
in communication with the pipe 9.
With the centrifugal pump running there is beer
under pressure acting on the bottom of the piston
21, but beer cannot yet escape through the pipes 19
and 9, the flow switch 11, the pipe 12 and the outlet 15 because the closure member 39 of the valve 14 is
held closed by a spring 40.
Upon closure of the push-button dispense switch
32, the controller 22 is operated to cause it to
energise the coil 30 of the valve 14 and move the
closure member 39 off its seat so that the piston 21
starts to rise under the pressure of the beer acting on
its underside and beer starts to flow through the
pipes 19 and 9 and thence through the flow switch
11, the pipe 12 and the valve 14 to the dispensing
outlet 15. As soon as flow starts through the flow
switch 11, contacts of this flow switch are closed and
this operates the controller 22 to hold the valve 14
open and to hold the valves 4 and 5 in the positions
already described. This state of affairs continues even though the dispense push-buton switch 32 is
released.
The piston 21 rises until it reaches the top end of
the cylinder 20 and when this happens flow through
the flow switch 11 ceases. As soon as this happens,
the contacts of the flow switch 11 open and this
causes the controller 22 to shut the valve 14. The
flow switch 11 does not however open for a finite
time after the flow through it has ceased and in
consequence there is a small time lag after flow has
ceased before the valve 14 is closed. During this time
the pressure in the pipe 12 falls and some fobbing of
the beer in this pipe and in the valve 14 upstream of
the closure member 39 may occur.
When the controller 22 has closed the valve 14, it
then energises the coil 25 of the valve 4 and de-energisesthe coil 26 of the valve 5. At this time the controller 22 keeps the motor of the centrifugal pump in operation. Accordingly beer under pressure is supplied through the pipe 3, the port 17 and the pipe 19 to the upper end of the cylinder 20 so that the beer pressure acts on the top surface of the piston 21. Owing to the energisation of the coil 25, the port 26 is now in communication with the port 6 and hence the piston is able to move a very small distance downwards so that it re-pressurises the beer in the pipe 12 and forces the carbon dioxide and any fob that may have formed back into solution in the beer so that the pipe 12 again becomes filled with liquid beer.After this has happened, the controller 22 then switches off the motor of the centrifugal pump.
At the next cycle of operations, when the pushbutton dispense switch 32 is closed again, the controller 22 sets the motor of the centrifugal pump into operation again and the piston 21 then moves downwards to the bottom end of the cylinder 20 to dispense a further measure of beer.
Even though during each dispensing operation the piston does not move in one direction through its full stroke, a full measure of beer is still dispensed because the main movement of the piston in one direction plus the small return movement in the other direction means that the total swept volume of the piston is equal to the full stroke of the piston and it is this that governs the volume of the beer which is dispensed.
At the end of the movement of the piston downwards to the bottom of the cylinder 20, and after the valve 14 has been closed by the controller 22, the valves 4 and 5 are changed over again to the positions initially described so that the piston makes a small upward movement once again to repressurise the beer in the pipe 12 and remove any fob which may have formed.
Claims (4)
1. A metering system for dispensing measured volumes of potable carbonated liquid, the system comprising a liquid pump having an outlet connected through ducting and electrically operated valves to a metering chamber having a metering member which is freely movable to and fro in the chamber, liquid outlet ducting connected through further electrically operated valves to the chamber and leading to a liquid dispensing outlet fitted with an electrically operated shut-off valve, a flow switch in the outlet ducting, an electronic controller which controls the valves and the pump and is connected to the flow switch, an a manually-operated switch for setting the system in operation to dispense a measured volume of liquid, the valves and the pump being so controlled by the controller that, upon one operation of the manually operated switch, liquid is pumped into the chamber on one side of the metering member to cause the member to move in one direction to dispense a measured volume of liquid from the chamber on the other side of the member and, upon a further operation of the manually operated switch, liquid is pumped into the chamber on the other side of the member to cause the member to move in an opposite direction to dispense a measured volume of liquid from the chamber on the one side of the member, wherein the controller is so constructed that it operates the valves and the pmp in a sequence such that when the metering member reaches the end of its movement in one direction and flow through the outlet ducting ceases, the flow switch is actuated to cause the shut-off valve to be closed and then the valves are operated to cause the pump to be connected to the chamber on the other side of the metering member and the outlet ducting to be connected to the chamber on the one side of the metering chamber before the pump is stopped, whereby the pump applies pressure through the metering memberto the liquid in the outlet ducting and this pressure is maintained owing to the prior closure of the shut-off valve.
2. A system according to Claim 1, in which the chamber is a cylinder and the metering member is a piston.
3. A system according to Claim 1 or Claim 2, in which the controller is constructed to keep the pump in operation for substantially one second after the shut-of valve has closed.
4. A system according to Claim 1, substantially as described with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7922868A GB2028767B (en) | 1978-08-31 | 1979-07-02 | Metering system for dispensing beer or other potable carbonated liquids |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7835151 | 1978-08-31 | ||
| GB7922868A GB2028767B (en) | 1978-08-31 | 1979-07-02 | Metering system for dispensing beer or other potable carbonated liquids |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2028767A true GB2028767A (en) | 1980-03-12 |
| GB2028767B GB2028767B (en) | 1982-06-23 |
Family
ID=26268709
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7922868A Expired GB2028767B (en) | 1978-08-31 | 1979-07-02 | Metering system for dispensing beer or other potable carbonated liquids |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2028767B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0051094A1 (en) * | 1980-11-03 | 1982-05-12 | Alumasc-Grundy Limited | Apparatus for metering liquids |
| DE3701804A1 (en) * | 1986-01-25 | 1987-07-30 | Ford Werke Ag | FLOW METER FOR FLUIDE |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10899597B2 (en) | 2018-02-16 | 2021-01-26 | Cleland Sales Corporation | Fluid control shutoff and pump assembly for a beverage dispensing machine |
-
1979
- 1979-07-02 GB GB7922868A patent/GB2028767B/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0051094A1 (en) * | 1980-11-03 | 1982-05-12 | Alumasc-Grundy Limited | Apparatus for metering liquids |
| DE3701804A1 (en) * | 1986-01-25 | 1987-07-30 | Ford Werke Ag | FLOW METER FOR FLUIDE |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2028767B (en) | 1982-06-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19950702 |