A coaxial connector

Abstract

A coaxial connector 1 comprising a body 2 with an outer wall 3 and an inner wall 4 supported within an outer wall by a bridge portion 5 extending across an outer flow path W. The connector seals wit

Description

The present invention relates to a coaxial connector. In particular, it is designed as a connector for pipework containing two flow paths arranged coaxially. The connector has been specifically designed for a coaxial flow in which the central path is a beverage, and the outer path is a coolant path for a coolant such as chilled water. However, the invention is applicable to any coaxial flow of liquids. The invention has a particular application to connectors which are used in bars, pubs, clubs and the like. Usually kegs / barrels of beverage are stored, for example, in a cellar, or other location which is generally remote from the location at which the beverages are dispensed. A pipe is then connected between the keg and the dispenser. If the beverage is required to be dispensed cold, coaxial pipework is used in which the inner flow path is the beverage and the outer flow path is a flow of cooling water. It is desirable to have an accurate measure of the volume of the beverage which has been dispensed for stock control reasons. It is known to do this by installing a flow meter in the beverage line. In order to do this, the inner flow path containing the beverage needs to be “broken out of” the outer flow path. To do this, the coaxial flow line is connected to a first splitter (for example the JG Polarclean Parallel Connector) which isolates the inner flow path from the outer flow path. The inner flow path is then connected to a flow meter which measures the flow rate of the beverage. A connector similar to the splitter, but connected in reverse is provided in order to bring the inner flow path back into the outer flow path in order that the downstream flow may continue as a coaxial flow. In this break out region, however, the beverage is not surrounded by the coolant water. Although this path may be relatively short, the beverage can remain in this region for a significant time given the intermittent nature of the beverage flow. This creates a potential warm spot which provides a region in which bacteria can grow. According to a first aspect of the present disclosure, there is provided a coaxial connector comprising a body with inner and outer coaxial through flow paths; the body having an outer wall and an inner wall supported within the outer wall by a bridge portion extending across part of the outer flow path; an inlet end at which the outer wall is configured to retain and seal with an outer inlet pipe and at which the inner wall is configured to retain and seal with an inner inlet pipe, and an outlet end at which the outer wall is configured to retain and seal with an outer outlet pipe and at which the inner wall is configured to retain and seal with an inner outlet pipe; and an auxiliary port extending through a side wall of the body across the bridge portion without breaking into the outer flow path and extending into the inner flow path. This provides a connector with a built-in auxiliary port. This has been specifically designed to accommodate a flow meter. However, it can also be used for other features such as a shut-off valve or sensor. Rather than requiring separate connectors to break out the inner flow path from the outer flow path, the present disclosure uses a single connector. Rather than having to get the inner flow out, it allows auxiliary equipment to be brought in to the inner flow path. Not only does this provide a much better and more cost effective connection, it also allows the inner flow path to be fully surrounded, or surrounded to a significant extent by the outer flow path along the full extent of the connector. This prevents or significantly reduces the opportunity for bacterial growth within warm spots in the inner flow path. The flow meter may be any conventional flow meter such as an ultrasonic flow meter. However, optionally the flow meter comprises a rotatable paddle wheel in the inner flow path. This provides an efficient and reliable way of monitoring the flow. The paddle wheel optionally has a sensor to detect rotation and a cable extending out of the body to transmit a flow measurement externally of the body. This provides a simple cost effective robust design of flow meter which allows simple monitoring of the flow rate. The auxiliary ports may contain an integral instrument. However, optionally, the connector further comprises an instrument housing mounted in and sealed to the auxiliary port. The instrument housing can be readily installed and removed for repair / replacement. This can be facilitated by the presence of a retaining cap mounted to the body to retain the instrument housing in the auxiliary port. The connector may be provided with a gripper such as a grab ring in order to retain each pipe on the body. However, optionally, the inlet and outlet pipes are each retained by a respective collet. This provides a simple reliable retaining means and lends itself to a push fit connection which readily allows the pipes to be released. The coaxial pipes may end in a common plane. Optionally, the inner pipe extends beyond the outer pipe. This allows the end of the outer pipe to be retained in the connector proximally of the end of the inner pipe. This allows the sealing and retaining means for each pipe to be axially spaced along the connector in order to reduce the diameter of the connector body. The connector may have axially spaced end stops for the inner and outer pipes. This ensures that each pipe can be inserted to a well defined position. In this case, the axial spacing between the ends of the inner and outer pipes should be set to be the same as the spacing between the end stops in order to allow both pipes to reach their respective stops without stressing the pipes. A second aspect of the disclosure provides a tool for preparing a coaxial pipe for connection to a connector, the tool comprising: a part tubular body with a passage extending along its length to allow an inner pipe to pass through; a first end of the tool having a stop face to prevent an outer pipe from entering the tool; a side wall of the tubular pipe having an opening; and a visible mark adjacent to the opening at a fixed axial distance from the first end to allow a line to be drawn on the inner pipe at a fixed distance from the end of the outer pipe. This allows the coaxial pipe to engage with the tool such that the outer pipe stops at the first end and the inner pipe enters the tubular body at least as far as the visible mark. This allows a user to make a mark on the inner pipe at a fixed distance form the end of the outer pipe. The inner pipe can then be cut at this mark such that the coaxial pipe has a known spacing between the ends of the inner and outer pipes. The cut pipe is then inserted into the connector which ensures that both ends will be at a well defined position in the connector. In the vicinity of the visible mark, the opening subtends and angle of at least 90° at the centre of the tool. This allows room for a line of reasonable length to be made on the inner pipe to facilitate the cutting process. There may be a second visible mark on the opposite side of the opening from the first mark and at the same axial distance from the first end as the visible mark. This allows the inner pipe to be marked between the visible marks which ensures that the inner pipe can be reliably marked in a straight line. At least one of the visible mark and second visible mark may be a notch facing towards the opening. Again, this facilitates the marking process. In order to release the outer pipe, the collet retaining it is depressed, and the outer pipe is removed. The collet retaining the inner pipe is at an inaccessible location in the connector. Optionally in the tool, the opening extends for the full length of the tool and is wide enough to allow the inner pipe to be inserted laterally into the tool, and the outer diameter of the tool at a second end opposite to the first end is smaller than the outer diameter of the outer pipe. This geometry allows the tool to also act as a release tool for the inner pipe. Once the outer pipe is removed, the tool can be fitted laterally over the inner pipe and slid axially into the connector to depress the collet retaining the inner pipe, thereby allowing it to be pulled out. The circumferential extent of the tool body may be greater at either end than it is in the middle. This allows the first end to provide a reliable stop for the outer pipe and / or the second end to provide reliable engagement with the collet for the inner pipe, while still allowing enough room for a reasonable length of mark to be made on the inner pipe. The present disclosure also extends to a combination of a coaxial connector according to the first aspect and a tool according to the second aspect wherein the tool is dimensioned to fit into the inlet end of the coaxial connector. The axial distance between the end stops may be equal to the axial distance from the first end of the tool to the visible mark. This allows the pipes to be cut to the correct size an inserted into the connector such that the ends of both pipes land reliably on their respective stops. According to a third aspect of the disclosure a method of attaching a coaxial pipe to a connector comprises: inserting an inner pipe of the coaxial pipe into a tool according to the second aspect such the inner pipe passes the visible mark, and the outer pipe abuts the first end of the tool; making a mark on the inner pipe at a location axially level with the visible mark; cutting off the end of inner pipe in a plane including the mark on the inner pipe; and inserting the cut coaxial pipe into a connector according to the first aspect. An example of a connector and tool will now be described with reference to the accompanying drawings, in which: Fig. 1 is a side view of the connector; Fig. 2 is a cross-section through horizontal plane A-A in Fig. 1; Fig. 3 is a view similar to Fig. 2 with the pipes in place and the flow paths indicated; Fig. 4 is a cross-section through a central vertical plane of the connector; Fig. 5 is a cross-section through line B-B in Fig. 1; Fig. 6 is a cross-section through line C-C in Fig. 1; Fig. 7 is a perspective view of the flow meter and its mounting; Fig. 8 is a perspective view of the connector prior to installation of the flow meter; Fig. 8A shows a detail of Fig. 8 in the area ringed; Fig. 9 is an exploded perspective view of the connector; Fig 10 is a schematic front perspective view of the tool and coaxial pipe; and Fig 11 is a rear view of the tool. The connector 1 is a coaxial connector which is designed to be used to connect two coaxial pipes. The coaxial pipes comprise an outer inlet pipe P1, an inner inlet pipe P2, an outer outlet pipe P3 and an inner outlet pipe P4, as shown in Fig. 3. The inner inlet pipe P2 leads from a beer keg to transport a flow of beverage B from the keg connector. The outer inlet pipe P1 has a flow of coolant water W which surrounds the beverage B. The coaxial pipe is attached to the top of a keg by a connector, as disclosed, for example, in WO2020 / 084276. The inner outlet pipe P4 transports the beverage B from the connector 1 to a dispenser. This is surrounded by cooling water W in the outer outlet pipe P3 which extends from the connector 1 most of the way to the dispenser. The water W is then recirculated via a cooling unit to the keg as is known in the art. The connector 1 can be positioned anywhere along the beverage line. However, ideally, it is positioned close to the keg to measure the flow rate as the beverage leaves the keg. The connector 1 comprises a moulded body 2 which forms a generally cylindrical outer wall 3 and a generally cylindrical inner wall 4 separated by a bridge portion 5 and a support web 6. The bridge portion 5 and support web 6 serve to locate the inner wall 4 centrally within the outer wall to retain it in place. They also provide a flow path for plastic into the inner wall 4 during the moulding process. The bridge portion 5 also provides a port as discussed below. The connections at an inlet end 7 are the same as those at the outlet end 8 and only the inlet end 1 connections are described below. Each pipe connection comprises an O ring to seal on the outer wall of the respective pipe, and a collet to grip the outer wall of the respective pipe as described in greater detail below. The inner pipe connection comprises an inner O ring 10 seated on a shoulder 11 within the inner wall 4. An inner cap 12 is fitted in the end of the inner wall 4 to retain inner collet 13 in place. The inner cap 12 has a cap angle 14 which cooperates with the inner collet 13 to grip inner inlet pipe P2 as is well known in the art. A support sleeve 15 is positioned adjacent to the inner face of the outer wall 3 proximally of the end of the inner wall 4. This provides a shoulder to support outer O ring 16 and is also provided with a number of circumferentially spaced radially inwardly extending lugs 17 to provide an end stop for the end face of the outer inlet pipe P1 as shown in Fig. 3. The sleeve 15 is trapped between the O ring 16 and the outer inlet pipe once inserted P1. An annular washer 18 abuts the proximal end of the outer O ring 16 in order to retain it in place an prevent it deforming.. An outer collet 19 is inserted into the proximal end of the body 2 with a collet ring 20 protruding from the end. The outer collet 19 is retained by an outer cap 21 which is fixed into the proximal end of the body 2 and is retained against a shoulder 22. The outer cap 21 provides a cap angle 23 for the outer collet 19. Outer inlet pipe P1 and inner inlet pipe P2 are inserted together into the connector 1. The pipes P1, P2 are cut with axially spaced ends as shown in Fig. 3. This is described in greater retail below. Upon insertion, the inner inlet pipe P2 lands on the shoulder 11 in the inner wall 4 and the outer inlet pipe P1 lands on the lugs 17. The inner inlet pipe is sealed by the inner O ring 10 and gripped by the inner collet 13. Similarly, the outer inlet pipe P1 is sealed by outer O ring 16 and gripped by the outer collet 19. Both pipes are therefore sealed and retained simply by inserting the coaxial pipe into the connector 1. The outer outlet pipe P3 and inner outlet pipe P4 are similarly inserted at the outlet end 8 and sealed and retained in place. As shown in Fig. 3, the connected pipes create two coaxial flows. A beverage flow path B is provided through the inner inlet pipe P2, inner wall 4 and inner outlet pipe P4. A water flow path W is provided in the annular space between the outer inlet pipe P1 and inner inlet pipe P2, the space between the inner wall 4 and the outer wall 3, and the annular space between outer outlet pipe P3 and inner outlet pipe P4. As can be seen in Fig. 3. The inner O ring 10 provides a seal for the water flow path W and also provides an outer diameter seal on the inner pipes P2 and P4 to seal the beverage flow path B. The outer O ring 16 seals on the outer diameter of the outer pipe P1 and P3 to seal the water flow path. The manner in which flow meter 30 is accommodated in the connector 1 will now be described. As previously mentioned, bridge portion 5 extends from the outer wall 3 into the inner wall 4. This provides a port 31 to accommodate the flow meter 30. The bridge part 5 extends across the gap between the outer wall 3 and inner wall 4 only in the region around the periphery of the port 31. As a result, the generally annular nature of the water flow path W is largely maintained along the connector. The bridge part 5 only partially obstructs the annular flow. Thus, for the vast majority of the connector, the beverage flow B is fully surrounded by water flow W. In a small portion of the connector adjacent to the bridge part 5 the beverage flow B remains surrounded to a significant extent by the water flow W. As such, this arrangement provides reliable cooling of the beverage flow B along its full flow path. This represents a significant improvement compared to routing the beverage flow B entirely outside of the water flow W. The illustrated flow meter is a Titan flow meter. This comprises a paddle wheel 32 attached to a housing 33 which is held in place by a cap 34. The paddle wheel 32 has the geometry shown in Figs. 2, 3 and 7 positioned in a chamber 35 at the bottom of the port 31 which is in fluid communication with the beverage flow path B. The housing 33 is sealed to the port by an O ring 36. The housing 33 is clamped in place by the cap 34 which is fitted onto a complementary boss 37 formed at the top of the port 31. The cap 34 is held in place by a plurality of screws 38. The paddle wheel 32 is provided with a sensor 39 which in this case, is a Hall effect sensor but any types of sensor may also be used. The sensor 39 is connected to a cable 40 which extends through the cap 34 to allow external monitoring of the flow rate. Although the present invention has been described in relation to a flow meter, the concept of allowing access to the central duct of a coaxial flow can be applied to other auxiliary equipment being inserted into the port 31. For example, the flow meter 30 can be replaced by a shut-off valve or a sensor for sensing a liquid condition. This may sense any condition such as temperature, viscosity or colour. In this case, the shut-off valve or sensor can make use of the same mounting arrangement described above. This can use the port 31, boss 37, cap 34, screws 38 and cable 40 used for the flow meter 30. The shut-off valve or sensor may be provided in an adapted version of the housing 33. Alternatively, bespoke components can be provided for mounting the shut-off valve or sensor. For the shut off valve, the cable 40 could be used to provide control signals to the shut-off valve. Alternatively, the cable 40 could be replaced by a spindle attached to an external handle to allow a manual shut-off. The tool for preparing the coaxial pipe will now be described with reference to Figures 10 and 11. The tool 50 has a tubular body 51 with a radially extending flange 52 at a first end 53. The tubular body generally has a cylindrical cross section with an opening 54, in this example, the opening extends from the first end to a second end 55 opposite to the first end 52. On one side of the opening is a first notch 56 which faces a second notch 57 on the opposite side of the opening. The notch could be replaced by some other marking such as a line, arrow or the like, embossed into or raised or printed on the outer face of the body 51 or the edge of the opening. Adjacent to the first end 53 a first enlarged circumferential portion 58 allows the flange 52 to extend for a greater proportion of the circumference than the central part of opening 54. The second end 55 has a second enlarged circumferential portion 59 which ensures that the second end 55 extends for a greater proportion of the circumference than the central part of the opening 54. As shown in Fig. 10, the tubular body 51 is marked with scissor indicia 60 denoting a cut line 61 level with the notches 56,57. In use, the tool 50 is fitted to a coaxial pipe P1 ,P2 or P3,P4. The end of the outer pipe P1 ,P3 abuts against the flange 53 while the inner pipe P2,P4 is pushed into the tool at least as far as the notches 56, 57. As shown in the Figures, the inner pipe P2,P4 is pushed all the way through so that it projects from the second end of the tool 50, although this is not essential. In this position, the user can mark 62 the inner pipe P2,P4 by drawing on the pipe with, for example, a marker pen, or by scoring the tube. The tool 50 is then removed from the end of the coaxial pipe and the inner pipe P2,P4 is cut in the radial plane passing through the mark 62. The distance between the first end 53 and the notches 56,57 is the same as the 5 distance between end stops in the connector for the outer P1 ,P3 and inner P2,P4 pipes as shown in Fig. 3. This ensures that, when the cut pipe is inserted into the connector, both pipes will reliably seat. The tool 50 has a second function as a release tool for the inner collet. 10 In order to disconnect the connector, the outer collet 19 is depressed into the body 2 to allow the outer inlet pipe P1 ,P3 to be pulled out of the connector. The tool 50 can then be pushed by urging the opening 54 laterally over the inner inlet pipe P2,P4. The tool is then slid axially into the body to depress the inner collet 13 allowing the inner inlet pipe P2,P4 to 15 be pulled out of the connector.

Claims

1. A coaxial connector comprising a body with inner and outer coaxial through flow paths;the body having an outer wall and an inner wall supported within the outer wall by a bridge portion extending across part of the outer flow path;an inlet end at which the outer wall is configured to retain and seal with an outer inlet pipe and at which the inner wall is configured to retain and seal with an inner inlet pipe, and an outlet end at which the outer wall is configured to retain and seal with an outer outlet pipe and at which the inner wall is configured to retain and seal with an inner outlet pipe; andan auxiliary port extending through a side wall of the body across the bridge portion without breaking into the outer flow path and extending into the inner flow path.

2. A coaxial connector according to claim 1, further comprising a flow meter in the auxiliary port to measure the flow in the inner flow path.

3. A coaxial connector according to claim 2, wherein the flow meter comprises a rotatable paddle wheel in the inner flow path.

4. A coaxial connector according to claim 3, wherein the paddle wheel has a sensor to detect rotation and a cable extending out of the body to transmit a flow measurement externally of the body.

5. A coaxial connector according to any preceding claim further comprising an instrument housing mounted in and sealed to the auxiliary port.

6. A coaxial connector according to claim 6 further comprising a retaining cap mounted to the body to retain the instrument housing in the auxiliary port.

7. A coaxial connector according to any preceding claim further wherein the inlet and outlet pipes are each retained by a respective collet.

8. A coaxial connector according to any preceding claim wherein the end of the outer inlet pipe is retained distally of the end of inner inlet pipe.

9. A coaxial connector according to any preceding claim wherein the end of the outer outlet pipe is retained distally of the end of inner outlet pipe.

10. A coaxial connector according to claim 8 further comprising axially spaced end stops for the inner and outer pipes.

11. A tool for preparing a coaxial pipe for connection to a connector, the tool comprising:a part tubular body with a passage extending along its length to allow an inner pipe to pass through;a first end of the tool having a stop face to prevent an outer pipe from entering the tool;a side wall of the tubular pipe having an opening; anda visible mark adjacent to the opening at a fixed axial distance from the first end to allow a line to be drawn on the inner pipe at a fixed distance from the end of the outer pipe.

12. A tool according to claim 11, wherein, in the vicinity of the visible mark, the opening subtends and angle of at least 90° at the centre of the tool.

13. A tool according to claim 11 or claim 12, further comprising a second visible mark on the opposite side of the opening from the first mark and at the same axial distance from the first end as the visible mark.

14. A tool according to any of claims 11 to 13, wherein the visible mark is a notch facing towards the opening.

15. A tool according to claim 13, wherein the second visible mark is a notch facing towards the opening.

16. A tool according to any of claims 11 to 15, wherein the opening extends for the full length of the tool and is wide enough to allow the inner pipe to be inserted laterally into the tool, and the outer diameter of the tool at a second end opposite to the first end is smaller than the outer diameter of the outer pipe.

17. A tool according to any of claims 11 to 16, wherein the circumferential extent of the tool body is greater at either end than it is in the middle.

18. A combination of a coaxial connector according to any of claims 1 to 10 and a tool according to any of claims 11 to 17, wherein the tool is dimensioned to fit into the inlet end of the coaxial connector.

19. A combination according to claim 18 when dependent on claim 10, wherein the axial distance between the end stops equals the axial distance from the first end of the tool to the visible mark.

20. A method of attaching a coaxial pipe to a connector, the method comprising: inserting an inner pipe of the coaxial pipe into a tool according to any of claims 11 to17 such the inner pipe passes the visible mark, and the outer pipe abuts the first end of the tool;making a mark on the inner pipe at a location axially level with the visible mark; cutting off the end of inner pipe in a plane including the mark on the inner pipe; and inserting the cut coaxial pipe into a connector according to any of claims 1 to 10.s

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