GB2262596A - Method of supplying gas and apparatus for use in the method - Google Patents

Abstract

For controlling the supply of gas under pressure from either one of two containers (10, 11), there is provided shut-off valves (17, 18). Operation of these valves is controlled by a timer and pressure-responsive switches (PS1, PS2). <IMAGE>

Description

Title: Method of supplying gas and apparatus for use in the method.

Description of Invention According to a first aspect of the invention, there is provided apparatus for supplying a gas under pressure comprising one or more containers containing the gas under pressure, a gas outlet and flow-control means for controlling the flow of gas from the container or the containers through the outlet, wherein the flow control means includes a timer for providing timing signals at pre-selected times and shut-off means responsive to one timing signal to shut off flow through the shut off means to the outlet and responsive to another timing signal to permit flow from the container or one of the containers to the outlet through the shut off means.

The apparatus preferably comprises at least first and second of said containers, the shut off means including respective valves associated with each of the containers. There may be interposed between the valves and the gas outlet means for preventing flow of gas from one of said valves to the other.

In the preferred apparatus, there is connected with each of said containers upstream of the associated valve a pressure-responsive device for providing an output signal when the pressure in the container falls below a threshold value and wherein the shut off means responds to the output signal by closing the valve associated with the container and opening the other valve.

The preferred flow control means includes selector means for identifying the valve which is closed upon generation of the one timing signal and for selecting the same valve for opening when the other timing signal is generated.

The invention is useful in the dispensing of beverages by means of gas pressure applied to the beverages. It is common to use a cylinder containing carbon dioxide under pressure as a source of pressure to be applied to a beverage in a barrel or other container, in order to drive the beverage from the container along a pipe to a valve, through which the beverage is dispensed. Usually, a beverage is stored in a barrel or other container which is below the valve through which the beverage is to be dispensed and pressure is applied to the beverage to drive the beverage up to the valve. It is common practice to connect a cylinder of carbon dioxide with a barrel and to subject the beverage in the barrel to carbon dioxide under pressure continuously until the cylinder is exhausted. This may be for a period of several weeks.

Applying carbon dioxide under pressure from a cylinder continuously to beverage in a barrel for a period of a week or more has disadvantages. Firstly, the carbon dioxide dissolved in aqueous beverages so that the amount of carbon dioxide dissolve per unit volume of beverage rises to a value considerably greater than the optimum value, which is established during manufacture of the beverage.

Secondly, leakage of carbon dioxide from the pipework and fittings inevitably occurs so that a proportion of the carbon dioxide, in many cases, a major proportion, is wasted. Escaped carbon dioxide is a hazard to persons, particularly in cellars which are not well ventilated and which do not have doorways or other openings at floor level. Under such conditions, escaped carbon dioxide may accumuiate and displace air from the cellar.

By means of apparatus embodying the first aspect of the invention, the gas flow path from the container of carbon dioxide to the beverage can be closed at times when the beverage is not to be dispensed and can be opened only during those hours when dispensing of the beverage takes place. When the flow path is closed by means of a valve, the pressure in the carbon dioxide downstream of the valve falls, owing to leakage and/or solution in the beverage. This fall in pressure reduces loss by leakage and reduces the dissolution of the carbon dioxide in the beverage.

According to a second aspect of the invention, there is provided a method for supplying a gas under pressure comprising the steps of providing first and second containers containing the gas under super-atmospheric pressure, a gas outlet and flow control means for controlling the flow of gas from the containers through the outlet, the flow control means including a timer for providing timing signals at pre-selected times and shut off means responsive to one timing signal to shut off flow through the shut off means to the outlet and responsive to another timing signal to permit flow from one of the containers to the outlet and connecting the containers with the flow control means, wherein the containers are connected concurrently with the flow control means, gas is supplied from a first of the containers through the shut off means to the gas outlet for a selected supply period, during the supply period, the shut off means prevents flow of gas from the second container to the outlet, the timer provides the one timing signal and the shut off means responds by shutting off flow from the first container to the outlet to commence a no-supply period, during the no-supply period, the first and second containers both remain connected with the flow control means, at the end of the no supply period, the timer provides the other timing signal and the shut off means responds by permitting resumption of flow from the first container to the outlet, the second container remaining connected to the flow control means but the shut off means continuing to prevent flow from the second container to the outlet unless and until the first container is exhausted, in which event the shut off means permits flow from the second container to the gas outlet and prevents further flow from the first container to the gas outlet.

An example of apparatus embodying the invention will now be described, with reference to the accompanying drawings, wherein: FIGURE 1 shows a diagrammaticrepresentaflon of certain components of the apparatus and FIGURE 2 shows a diagram of an electrical circuit of the apparatus.

The apparatus illustrated in Figure 1 comprises a first container 10 and a second container 11, both of which contain a gas under pressure. In the example illustrated, the gas is carbon dioxide. The containers may additionally contain liquified gas or gas adsorbed on a solid medium or dissolved in a liquid medium. The apparatus further comprises flow-control means for controlling flow of gas from the containers 10 and 11, to a gas outlet 12.

The flow control means comprises shut off means 13 interposed between the containers 10 and 11 on the one hand, and the gas outlet 12 on the other hand. The flow control means further comprises manually-operable changeover valve means 14 through which there can be established a flow path from either one of the containers 10 and 11 to the outlet 12, by-passing the shut off means 13. The change over valve means 14 preferably has a single handle, by means of which this valve means can be set in any selected one of a first condition, in which it prevents flow from either of the containers to the gas outlet 12, a second condition in which flow from the container 10 to the gas outlet is permitted and a third condition in which flow from the container 11 to the gas outlet is permitted. Non-return valves 15 and 16 are interposed between the change over valve means and the gas outlet 12.

The shut off means 13 comprises a solenoid-operated, normally closed shut-off valve 17 connected with the container 10 and a solenoid-operated, normally closed shut off valve 18 connected with the container 11. These valves are connected to opposite end of a shuttle valve 19 having an intermediate port connected with the gas outlet 12. The shuttle valve 19 is operated by the pressure of gas at the inlet ports of the shuttle valve and ensures that, when a flow path from one of the containers 10 and 11 to the gas outlet 12 is open, the flow path between the gas outlet and the other container is closed.

The flow control means further comprises selector means for selecting one of the shut off valves 17 and 18 for opening when gas is to be supplied under pressure from one of the containers 10 and 11 to the gas outlet 12. The selector means includes relays R1 and R2. Relay R1 has normally open contacts connected in series with the operating solenoid of shut off valve 17 so that electrical power for opening the valve 17 can be supplied through the relay R1, when power is supplied to the energising winding of that relay. The relay R1 also includes normally closed contacts connected in series with the energising winding of the relay R2 so that relay R2 cannot be energised whilst relay R1 is energised.

The selector means further comprises a pressure-actuated, electrical switch PS1 which is coupled mechanically with a diaphragm exposed to the pressure in the container 10. When the pressure in container 10 is above a selected threshold value, the diaphragm holds closed contacts of the switch PS1 through which relay R1 can be energised. When the pressure falls below the threshold value, the contacts of switch PSI through which relay R1 is energised are opened and contacts of switch PS1 through which warning lamp 20 or other indicator is energised are closed to provide a continuous indication of the low pressure in container 10.The selector means also includes a further pressure actuated switch PS2 associated with the container 11 and with the relay R2 in a manner corresponding to that in which switch PS1 is associated with the container 10 and with the relay R1. A further warning lamp 21 is energised when the pressure in container 11 falls below the selected threshold value. The pressure switches may be adjusted to operate at a selected pressure within a wide range, for example a range from 3 to 150psi.

The flow-control means further comprises an electrically driven timer 22 having contacts through which electrical power can be supplied to the solenoid of valve 17 through contacts of relay R1 and also to the solenoid of valve 18 through contacts of relay R2 during selected periods. During other periods, power cannot be supplied to the solenoid of either of the valves 17 or 18, so that these valves will remain closed. However, the timer does not affect energisation of the relays R1 and R2 so that one or other of these relays continues to be energised when the timer operates to discontinue energisation of one or other of the valves 17 and 18. Accordingly, information as to which of the valves 17 and 18 was open is retained by the selector means.

During supply of gas from container 10 to the outlet 12 through the valve 17, the relay R1 is energised. A continuous visual indication of this condition is given by a further indicator 23, which is energised through contacts of the relay R1. If the pressure in container 10 falls below the threshold valve, the relay R1 is de-energised by switch PS2. This allows normally closed contacts of the relay R1 through which relay R2 can be energised to close. The contacts through which indicator 23 is energised open and the contacts through which the solenoid of valve 15 is energised also open. Provided that the pressure in container 11 is above the threshold value, relay R2 is energised immediately.

This closes contacts through which the solenoid of valve 18 is energised, closes the contacts through which a further indicator 24 is energised and opens contacts of the relay R2 connected in series with the energising winding of relay R1.

According, relay R1 cannot again be energised until relay R2 is de-energised.

Operation of pressure switch PS1 when the pressure in container 10 falls below the threshold valve also energises indicator 20. If the equipment is subsequently inspected, this will indicate that the supply of gas in container 10 is substantially exhausted. Container 10 can then be replaced by a fully-charged container.

When this container is installed, switch PS1 will be operated once more to open the contacts through which indicator 20 is energised and the close the contacts through which relay R1 could be energised.

It will be understood that the indicators 20, 21, 23 and 24 could be positioned remotely from the valves, in a location where they can readily be observed.

When the apparatus is used for supplying gas under pressure to one or more barrels containing beverages, in order to drive the beverages from the barrels to dispensing valves, the timer is arranged to permit opening of one of the shut off valves from the opening time of the premises where the beverages are to be dispensed to the closing time of those premises. At closing time, the shut off valves are automatically closed and the pressure of carbon dioxide downstream of the shut off valves gradually falls.

The apparatus may be used for controlling the supply of gases other than carbon dioxide, especially when a gas is to be supplied only during a predetermined period but continuation of supply throughout that period is required, even if a first container of the gas becomes exhausted. If continuity of supply is not essential, then the container i1 and associated components may be omitted from the apparatus.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (9)

1. Apparatus for supplying a gas under pressure comprising one or more containers containing the gas under pressure, a gas outlet and flow-control means for controlling the flow of gas from the container or containers through the outlet, wherein the flow control means includes a timer for providing timing signals at pre-selected times and shut off means responsive to one timing signal to shut off the flow from the container or containers through the shut off means to the outlet and response to another timing signal to permit flow of gas from the or one of the containers to the outlet through the shut off means.

2. Apparatus according to Claim 1 wherein there are a first and a second of said containers and the shut off means includes respective valves associated one with each of said containers.

3. Apparatus according to Claim 2 wherein there is connected with each of said containers upstream of the associated valve a pressure-responsive device for providing an output signal when the pressure in the container falls below a threshold value and wherein the shut off means responds to the output signal by closing the valve associated with the container and opening the other valve.

4. Apparatus according to Claim 2 wherein the flow control means includes selector means for identifying the valve which is closed upon generation of the one timing signal and for selecting the same valve for opening when the other timing signal is generated.

5. Apparatus according to any one of Claims 2 to 4 wherein there is interposed between the valves and the outlet means for preventing flow of gas from one of said valves to the other.

6. Apparatus according to any one of Claims 2 to 5 further comprising a manually operable change-over valve having a handle, respective inlets connected with the containers upstream of the flow control means and respective outlets, each connected via a non-return valve with said gas outlet.

7. A method of supplying a gas under pressure comprising the steps of providing first and second containers containing the gas under super-atmospheric pressure, a gas outlet and flow control means for controlling the flow of gas from the containers through the outlet, the flow control means including a timer for providing timing signals at pre-selected times and shut off means responsive to one timing signal to shut off flow through the shut off means to the outlet and responsive to another timing signal to permit flow through one of the containers to the outlet and connecting the containers with the flow control means, wherein the containers are connected concurrently with the flow control means, gas is supplied from a first of the containers through the shut off means to the outlet for a selected period, during supply of gas from the first container to the outlet, the shut off means prevents flow of gas from the second container to the outlet, the timer provides the one timing signal and the shut off means responds by shutting off flow from the first container to commence a no-supply period, during the no-supply period, both containers remain connected with the flow control means, at the end of the no-supply period, the timer provides the other timing signal and the shut off means responds by permitting resumption of flow from the first container to the outlet, the second container remaining connected to the flow control means but the shut off means continuing to prevent flow from the second container to the outlet unless and until the first container is exhausted, in which event the shut off means permits flow from the second container to the outlet until the one timing signal is again provided.

8. Apparatus substantially as herein described with reference to the accompanying drawings.

9. Any novel feature or novel combination of features disclosed herein or in the accompanying drawings.