GB2135693A - Pressurised gas installations and fluid control units - Google Patents

Abstract

A pressure gas source (2) is connected through a demand valve (6) to a number of containers (4) to maintain a positive pressure in the containers. For each container the connection is made through an anti-bacterial filter (18) on the outlet side of a stop valve (16), so that individual containers can be connected and disconnected without contaminating containers that are still connected. Further stop valves (44, 34) provided at the inlet and outlet of the demand valve. <IMAGE>

Description

SPECIFICATION Pressurised gas installations and fluid control units This invention relates to pressurised gas installations and to control units for such installations.

It is sometimes required, in processes such as brewing, to maintain a positive gas pressure in a number of containers while being able to remove and replace individual containers from time to time. In large-scale industrial installations, where capital cost may be a secondary consideration, permanent piping systems with appropriate valving from a common pressure source may be provided.In smaller scale installations where low capital cost is the aim, or where a demountable system is required because of space considerations, it would also be preferable to use a common pressure source but practical and economical control valve systems are not available so that problems arise, such as wastage of pressurising gas when changing a container, or even the risk of contamination through the need to break connections in the gas supply line or through permitting interconnection between different containers. Home brewing installations are an example of where such problems may arise but where the capital cost of overcoming them with the equipment at present available may be prohibitive.

According to one aspect of the present invention, there is provided a connection arrangement for a supply of gas from a pressurised gas source to a container, comprising respective means for connection to said source and to said container, a pressure regulator for a gas flow between said source and the container, and anti-contamination filter means between the pressure regulator and the container connection means.

According to another aspect of the invention, there is provided a connection arrangement for a supply of gas from a pressurised gas source to a plurality of containers, comprising respective means for connection to said source and to the individual containers, a common pressure regulator for a gas flow between said source and the containers, and anti-contamination filter means for said gas flow.

According to a further aspect of the invention, there is provided a demand valve for the regulation of a pressurised gas supply, where a substantially axial throughflow path is provided for the gas through a body of the valve between coaxial inlet and outlet spaces, a reciprocatory piston coaxially within the body being arranged to urge a normally closed valve member in said path to an open position, the piston being displaceable in response to the demand valve outlet pressure to operate said member and allow further gas through the valve to maintain a predetermined outlet pressure from a high pressure supply.

Preferably, said valve member is an axially displaceable operating member disposed coaxially in said gas path and a permeable gas filtration element may be interposed between said member and the piston for transmitting the opening movement of the piston to the valve member.

According to yet another aspect of the invention, there is provided a container stop valve assembly comprising a mounting member arranged to be sealingly secured to an inlet opening of the container, said mounting member having a stop valve mechanism coaxial with and at an outer end of a passage through the mounting member, and inwardly of said mechanism a filter mechanism disposed in or at the end of said passage. Advantageously, the stop valve mechanism and/or the filter member are coaxial with a rectilinear passage through the mounting member.

The stop valve mechanism may comprise inner and outer members and a screw thread connection for relative axial displacement of the members, said inner and outer members being provided with co-axial gas passages that can be sealed from each other by a closure member brought into operation by said axial screwing movement. The stop valves at the gas conduit branches between the demand valve and the container stop valves may be similarly constructed.

A preferred feature of each of the flow control units is that the axial flow configuration described can be provided by generally axially symmetrical elements which can be provided by generally axially symmetrical elements which can be very economically produced in small batches by turning operations, including both material removal operations and material deforming operations.

By way of example, the present invention will be described in more detail with reference to the accompanying drawings, wherein: Fig. 1 is a schematic illustration of a pressurised gas installation incorporating the invention, Fig. 2 is an axial section of the demand valve of the installation in Fig. 1, Fig. 3 illustrates a detail of the valve in Fig. 2, Fig. 4 is an axial section of a conduit branch stop valve in the installation of Fig. 1, and Fig. 5 is an axial section of a container stop valve in the installation of Fig. 1.

The installation shown in Fig. 1 is intended for beer brewing, in particular brewing a number of barrels of beer at a time on a relatively small scale, such as may be practised for home consumption.

In the process, the barrels must be maintained at a positive pressure with an inert gas to ensure no contamination, and it is known to use carbon dioxide from a commercially available pre-charged cylinder for this purpose. The method commonly used may amount to no more than injecting an approximate quantity of gas into the barrel at the start of the brewing process, with no close control of the increase of pressure in the barrel, and then relying solely on the gases of fermentation to maintain the positive pressure in the barrel for the remainder of the process.

In the installation shown in Fig. 1, the gas pressure source 2 is arranged to be continuously connected to a barrel 4 through a pressure regulator in the form of a demand valve 6 which can both top up the barrel pressure during the brewing process and at the same time regulate the flow of gas in dependence upon the barrel pressure. The installation also has means for connecting a number of barrels to the same pressure source in a way which ensures that there is no contamination of one barrel by another.

Supply line 8 from the pressure regulator comprises one or more junction pieces 10 from which one or more branches extend each with a stop valve 1 2. The line 8 itself terminates at a further stop valve 1 2. For each container, there is a top connection 14 each of which comprises a stop valve 1 6 and an anti-bacterial filter 1 8 (Fig.

5) mounted on a screw cap C. The filter is shown here in the interior of a barrel, but it could alternatively be located on the exterior. The filter may be a commercially available type manufactured by Millipore (UK) Limited under the Registered Trade Mark "MILLEX". When a barrel is removed from the installation, therefore, the stop cock 1 6 is first closed to prevent loss of pressure from the inlet line and the cap C released from the barrel; no sterilisation is needed afterwards because the filter continues to protect the line upstream from it.

The installation may be very simply modified to connect in further barrels, without disturbing the brewing process in the barrels already connected.

For each additional barrel, the downstream end of the supply line 8 is disconnected (the existing barrels having been closed off by use of thier stop valves), and a junction piece 10 is mounted on it, together a stop valve 1 2 on an outlet branch. This branch is connected to the barrel previously connected to the end of the supply line and using a further stop valve 1 2 and connection 1 4 secured to its top cap C the new barrel is ooupled to the supply line. The connections between the demand valve 6, the Yjunction pieces 10 and the connections 14 can be made using flexible tubing 20. The filters 1 8 continue to protect each barrel from cross-contamination as barrels are added or removed from the installation.It is also a feature of this arrangement that a common pressure is maintained in all the barrels connected into the installation, with gas being transferred from one barrel to another through the filters, depending on the different rates of fermentation. This allows beer to be drawn off for consumption while still connected to the installation without risk of loss of pressure.

A preferred form of demand valve 6 is illustrated in Figs. 2 and 3. It comprises a cylindrical body in two parts 22, 24 connected by a screw thread 26 to form an internal chamber 28 in which there is a control piston 30. Co-axial with the chamber at opposite ends thereof there are inlet and outlet passages 32, 34 which are interconnected by a central passage 36 in the piston. A porous bronze pad 38 acts as a filter at the entry to the passage 36. The rear face of the piston is maintained at atmospheric pressure normally, by virtue of a vent port 40 in the chamber wall, the front and rear faces of the piston being sealed from each other by O-ring 42.

In the inlet passage of the valve 32 there are two stop valves in series. Firstly, a spring loaded ball 44 keeps the passage closed until the valve has been screwed onto the adaptor 46 of the cylinder 2 providing the pressurising gas. A pin 48 projects from the cylinder outlet and once the 0ring seal 46 has been engaged between the demand valve and the cylinder the pin is depressed to allow the cylinder gas pressure to push the ball off its seating. Before gas can enter the piston chamber, however, the second stop valve 50 must be opened, this conveniently being a Schrader (R.T.M.) standard valve, with a screwthreaded body sealingly engaging the inlet passage 32 and an axial stem 52 spring-biased to the closed position of the valve in which the end of the stem 52 projects into the piston chamber 28.

Movement of the piston towards the valve causes the valve to open, by abutment of the porous pad 38 against the valve stem 52. The piston is normally urged towards the valve by a compression spring 54 but the inlet gas pressure acts against the spring.

In the outlet passage 34 of the demand valve there is a stop cock 56 which conveniently has the same mechanism as the stop cocks at the junction pieces 1 0. In each case the valve body 58 (the final portion of the body part 22 in the case of the demand valve) has a screw thread connection 60 with a collar 62, and engages non-rotatably an inner tubular member 64, which is axially held on the collar but does not rotate therewith. Rotation of the collar on its screw thread therefore moves the tubular member axially to bring a resilient sealing plug 66 on one end of it into and out of engagement with a seating 68 at the end of an axial fluid passage in the valve body 58.Once the collar has been unscrewed sufficiently to lift the plug 66 from its seating, gas can flow through the small clearance between the adjacent periphery of the tubular member and the valve body, as far as a sealing ring 72, and by way of cross-bore 74 can flow through the central bore 76 of the tubular member to the other end of the valve. The flow can take place in either direction through the open valve.

In use, connection of the demand valve between the gas pressure source 2 and an unpressurised barrel 4 will initially allow a flow of gas through the valve, the piston spring acting through the porous pad to displace the core member 52 and hold its valve open. As the container becomes charged and the pressure at the demand valve outlet increases, so will the pressure on the piston forward face increase, acting against the spring. Since the rear face of the piston is maintained at atmospheric pressure, the piston will move against the spring force and the valve progressively closes, reducing the admission of pressure fluid, until equilibrium position is established, which is dependent upon the outlet or container pressure and the spring pressure but which is independent of the supply pressure.In this way it is possible to maintain a relatively low, but positive pressure in a container.

A typical equilibrium pressure for beer brewing may be 10 p.s.i. whereas a conventional carbon dioxide cylinder may provide gas at 600 p.s.i.

Should the container pressure rise above the equilibrium pressure, e.g. because of fermentation within the containers, the piston will be forced further upwards until the port 40 is uncovered and the excess pressure is then vented.

The closure valves provided at the Y-junctions may be formed as integral parts of the junction pieces or they may be separate elements, as in the example shown in Fig. 4 where the valve is simply connected between a pair of flexible tubes.

Fig. 5 shows the arrangement of stop valve and filter mounted the top cap of a barrel, with a threaded smaller diameter upper portion of the valve body projecting from the cap to be clamped there by a ring nut (not shown) engaging screwthread 84, so applying sealing pressure to an 0ring 86 held between a larger diameter portion of the body and the inside face of the cap. The mechanism of the stop valve is the same as the stop valve at the demand valve outlet and the valve of Fig. 4, and corresponding references are used to indicate parts already described.

On the inner end of the axial passage from the stop valve the proprietary bacterial filter element 1 8 is secured in place by a screw threaded inner stem 8 with a sealing O-ring 90 between the filter and the body, so that all fluid flow to and from the container must pass through the filter element 1 8 held in the tubular carrier of the filter which is able to trap particles down to 0.22 microns in size.

When in use, therefore, the contents of the barrel are bacterially isolated from the remainder of the installation, while when a container is removed from the installation the filter ensures that despite the broken connection the remainder of the installation remains sealed to bateria.

It is a feature of all the constructions illustrated in Figs. 2 to 5 that the parts, or at least all the nonstandard parts, have an axis of symmetry which facilitates their production by turning methods, whether by cutting or forming processes, and that these constructions can therefore be very economically produced in small batches. The resulting straight throughflow passages provided in the various valves and other devices is itself an advantage in providing relatively compact units and in facilitating the cleaning of the fluid passages when required.

It will be understood that individual users will want to make up their own piping runs to suit their particular installation. It may be appropriate, therefore, to make available kits of parts which do not have any piping. Such kits may be sufficient simply to couple one barrel to a pressure source, and supplementary kits may be provided to allow an additional barrel to be linked into a connection arrangement subsequently.

Claims (14)

1. Connection arrangement for a supply of gas from a pressurised gas source to a container, comprising respective means for connection to said source and to said container, a pressure regulator for a gas flow between said source and the container, and anti-contamination filter means between the pressure regulator and the container connection means.

2. Connection arrangement for a supply of gas from a pressurised gas source to a plurality of containers, comprising respective means for connection to said source and to the individual containers, a common pressure regulator for a gas flow between said source and the containers, and anti-contamination filter means for said gas flow.

3. Connection arrangement according to claim 1 or claim 2 wherein the pressure regulator has a body providing a substantially axial through-flow path between coaxial inlet and outlet spaces, a reciprocatory piston coaxially within the body being arranged to urge a normally closed valve member in said path to an open position, the piston being displaceable in response to the outlet pressure to operate said member and allow a gas flow through the valve to maintain a predetermined outlet pressure from a higher pressure at the inlet.

4. Connection arrangement according to claim 3 wherein the valve member is an axially displaceable operating member disposed coaxially in said gas path and the filter means comprises a permeable gas filtration element interposed between said member and the piston, through which element the opening movement of the piston is transmitted to the valve member.

5. Connection arrangement according to any one of the preceding claims wherein the or each container connection means comprises a stop valve.

6. Connection arrangement according to claim 5 wherein the or each said stop valve comprises a rriounting member arranged to be sealingly secured to an inlet opening of its container, said mounting member having a stop valve mechanism coaxial with and at an outer end of a passage through the mounting member, and said filter means comprising a filter element disposed in or at an end of said passage.

7. Connection arrangement according to claim 6 wherein said filter element is disposed downstream of the stop valve mechanism.

8. Connection arrangement according to claim 6 or claim 7 wherein the stop valve mechanism and/or the filter element are coaxial with a rectilinear passage through mounting member.

9. Connection arrangement according to any one of claims 6 to 8 wherein the stop valve mechanism comprises inner and outer members and a screw-thread connection for relative axial displacement of the members, said inner and outer members being provided with co-axial gas passages that can be sealed from each other by a closure member brought into operation by said axial screwing movement.

10. Connection arrangement according to any one of claims 3 to 9 wherein the pressure regulator and/or each stop valve has an axially symmetrical configuration.

1 1. Connection arrangement for a supply of gas from a pressurised source, constructed and arranged for use and operation substantially as described herein with reference to the accompanying drawings.

12. A pressure regulator constructed and arranged for use and operation substantially as described herein with reference to Figs. 2 and 3 of the accompanying drawings.

13. A stop valve constructed and arranged for use and operation substantially as described herein with reference to Fig. 4 or Fig. 5 of the accompanying drawings.

14. A kit of parts for a connection arrangement for a supply of pressurised gas to a container, comprising respective connection means for a pressure gas source and a container, a pressure regulator valve, and said container connection means incorporating an anti-contamination filter.