AU2023203889A1

AU2023203889A1 - Dual contained piping system

Info

Publication number: AU2023203889A1
Application number: AU2023203889A
Authority: AU
Inventors: Maxwell John GOODE
Original assignee: Snosko Pty Ltd
Current assignee: Snosko Pty Ltd
Priority date: 2022-06-20
Filing date: 2023-06-20
Publication date: 2024-01-18

Abstract

A dual contained piping system is disclosed comprising a pipe having an inner pipe section and an outer pipe section surrounding the inner pipe section and defining an intermediate pipe space therebetween. It includes a housing comprising a housing body 5 defining a housing space and a plurality of housing ports. Each housing port is operatively coupled to the outer pipe section so that the intermediate pipe space and the housing space together form a continuous intermediate space through which liquid can flow. The housing ports also receive the inner pipe section therethrough. A pipe fitting is received in the housing space comprising pipe coupling formations that are operatively 10 connected to the inner pipe section of the piping system. A leak sensor in the continuous intermediate space is able to detect a leak of liquid out of the inner pipe section or a said pipe fitting at a point along the length of the continuous intermediate space. 15 Figure 4 2/8 24 12 34 4216 1 30 36 14 Figure 3 49 48 82 12 30 36 34 12 34 >~21 46 42 40 41 40 Figure 4

Description

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Figure 4

A DUAL CONTAINED PIPING SYSTEM FIELD

This invention relates to a dual contained piping system. The invention also relates to a housing for a dual walled piping system.

This invention relates particularly to a housing and a dual walled piping system, for conveying hazardous materials, e.g. hazardous liquid chemicals, and it will be convenient to hereinafter describe the invention with reference to this example application. However, at the same time, it is to be clearly understood that the invention is capable of broader application.

DEFINITION

In this specification, the term 'comprising' is intended to denote the inclusion of a stated integer or integers, but not necessarily the exclusion of any other integer, depending on the context in which that term is used. This applies also to variants of that term such as 'comprise' or 'comprises'.

In this specification, the term 'pipe fitting' is to be interpreted broadly and to include devices such as flow meters, temperature gauges, pressure gauges, other devices for measuring flow properties, and sensors of any kind including flow sensors, in addition to pipe tees and valves.

BACKGROUND

In some process applications, a tank storing a hazardous liquid may be spaced away from a plant where it is to be used. If a path from the tank to the plant does not have a bund, or other form of outer containment along its length, it is highly desirable, if not mandatory, that the liquid be conveyed to the plant in a dual contained piping system. The dual contained piping system comprises an inner pipe section in which the liquid is conveyed, and an outer pipe section circumferentially surrounding the inner pipe section, that provides a second or outer barrier to resist liquid escaping from the inner pipe section into the external environment. Thus, the dual contained piping system is required to safely convey the liquid so that if liquid leaks out of the inner pipe section, it can be contained within the outer pipe section.

The hazardous liquid is received within and contained within the inner pipe section and, in the event of a breach in the inner pipe section, the liquid will be contained within the outer pipe section thereby preventing leakage out into the external environment.

Dual contained piping systems are known in the prior art and some features of these are discussed below.

Applicant is aware of one prior art dual contained piping system that is made from rigid pipe sections. In this system, the pipe sections are welded together and cannot be disassembled. Further, the rigidity of the pipes limits their ability to cope with thermal expansion.

In another prior art dual contained piping system of which the Applicant is aware, one limitation is that a valve, pipe tee, pressure gauge or flow meter cannot be integrated into the system without creating more than one intermediate chamber or leak chamber. An inability to provide a single chamber along the length of the pipe is a severe limitation because it requires duplication of the leak sensing features and this adds cost and complexity to the system.

In yet another prior art system, the containment housing cannot accommodate a union coupling received within another union coupling and this limitation makes it difficult to achieve dual containment. Further in this system, the housing cannot be disassembled which is another limitation because it makes it difficult to gain access into the housing to perform maintenance on components of the system and, in particular, an inner pipe section and associated pipe fitting within thew housing.

Thus, the prior art dual contained piping systems of which the Applicant is aware have limitations.

The reference to prior art in the background above is not and should not be taken as an acknowledgment or any form of suggestion that the referenced prior art forms part of the common general knowledge in Australia or in any other country.

SUMMARY OF THE INVENTION

Applicant recognises that it would be beneficial if a dual contained piping system could be devised that at least ameliorates some of the drawbacks of prior art piping systems discussed above.

The technical challenge is to maintain a dual wall barrier to leakage in those positions where there is a valve or gauge in the piping system, and where there is a junction in the pipe.

According to one aspect of the invention there is provided a housing for coupling in line with a dual contained piping system comprising a pipe having an inner pipe section and a surrounding outer pipe section forming an intermediate pipe space between the inner and outer pipe sections, the housing comprising: a housing body defining a housing space that is configured to receive a pipe fitting therein for operatively connecting the pipe fitting to the inner pipe section of the piping system, wherein the housing comprises at least two housing ports for operatively and removably connecting the housing ports to the outer pipe section, and the housing ports are configured to be operatively connected to the outer pipe section such that the intermediate pipe space and the housing space together form a continuous intermediate space through which liquid can flow, while the housing ports also receive the inner pipe section therethrough.

Thus, the housing ports are configured so that the housing space opens into and communicates with the outer pipe section. To facilitate this, the housing ports are sized to receive the inner pipe section therethrough with a clearance.

The housing may include a leak sensor for detecting liquids within the housing space to indicate that a leak exists in the piping system.

The leak sensor may comprise one or more of an optic sensor, a float sensor, a vibration or an ultrasonic sensor that is operatively connected to a controller.

The housing ports may comprise stub arms extending out from the housing body and the stub arms may be configured for engaging complementary formations on the outer pipe section.

Each stub arm may comprise a female formation for engaging a complementary male formation on the outer pipe section, e.g. by means of complementary screw thread formations.

The housing body may comprise a removable closure that can be removed to provide access to the housing space within the housing body for performing maintenance.

Conveniently, the removable closure may extend across one full surface of the housing body.

The container body may comprise a bottom wall and a top wall, and the top wall may form the removable closure.

The top wall may be removably mounted on the container by means of complementary flanges on each of the top wall and the bottom wall, and fasteners fastening the complementary flanges to each other.

The bottom wall may comprise a base and a side wall extending up from the base.

The housing may comprise a transparent inspection zone for facilitating inspection of the housing space and look for signs of liquid therein.

Conveniently, the transparent inspection zone may be formed in the removable closure.

The transparent inspection zone may comprise at least one sight glass located underneath a removable cover that can be removed for inspecting the housing space. The removable cover helps to strengthen the housing over the sight glass to limit deformation of the sight glass when the housing space is pressurised.

The transparent inspection zone may comprise two transparent inspection plates, where one transparent inspection plates is used for admitting light into the container body, e.g. by shining a torch, and the other transparent inspection plate is for visually inspecting an interior of the housing space.

The housing body may have a stem opening formed therein for receiving a stem of a pipe fitting there through to enable the pipe fitting to be manually operable from outside of the housing space.

Conveniently, the stem opening may be formed in the removable closure.

The housing may comprise two said housing ports on opposite sides of the housing body so the pipe forms a straight line or linear path through the housing, e.g. the ports may be arranged at an angle of 180 degrees to each other.

Instead, the housing may comprise three said housing ports arranged at an angle of 90 degrees, i.e. orthogonal, to each other.

The housing may be configured and designed to enable it to be pressurised when connected to a pipe comprising inner and outer pipe sections forming part of a dual contained piping system.

In particular, the housing may be configured and designed to enable the housing space to withstand a pressure of at least 0.5 bar and optionally about 1 bar.

The housing body may be configured in the form of a substantially rectangular box, having a rectangular top wall. Instead, the housing body may be substantially circular cylindrical, having a circular top wall.

The housing body may be made of a corrosion resistant polymeric material.

The housing may include any one or more of the features, or combination of features, of the housing described in any other aspect of the invention.

According to another aspect of the invention there is provided a housing for coupling in line with a dual contained piping system comprising a pipe having an inner pipe section and a surrounding outer pipe section forming an intermediate pipe space between the inner and outer pipe sections, the housing comprising: a housing body defining a housing space that is configured to receive a pipe fitting therein for operatively connecting the pipe fitting to the inner pipe section of the piping system, wherein the housing comprises at least two housing ports for operatively and removably connecting the housing ports to the outer pipe section.

According to another aspect of the invention there is provided a dual contained piping system, comprising: a pipe comprising an inner pipe section and an outer pipe section surrounding the inner pipe section and defining an intermediate pipe space therebetween; a housing body defining a housing space and a plurality of housing ports, each housing port being operatively coupled to the outer pipe section so that the intermediate pipe space and the housing space together form a continuous intermediate space through which liquid can flow, while also receiving the inner pipe section therethrough; a pipe fitting received in the housing space comprising pipe coupling formations that are operatively connected to the inner pipe section of the piping system; and a leak sensor located in the continuous intermediate space for detecting a leak of liquid out of the inner pipe section or a said pipe fitting along the length of the continuous intermediate space, e.g. at a point along the length of the space.

The housing ports may be sized to receive the inner pipe section there through with clearance to permit liquid to flow freely between the outer pipe section and the housing space.

The outer pipe section may have ends releasably coupled to the housing ports so that the outer pipe section can be disconnected from the housing ports.

Each housing port may comprise an outer pipe coupling formation releasably coupled to a complementary outer pipe coupling formation on the outer pipe section, e.g. an end of the outer pipe section.

The outer pipe coupling formation on the housing port may comprise a female formation and the complementary outer pipe coupling formation on the outer pipe section may comprise a male formation. Optionally, the complementary male and female formations may be coupled to each other by means of a screw threaded engagement.

The complementary pipe coupling formation on the outer pipe section may further comprise a clamping nut for clamping the male formation onto the outer pipe whereby to seal the outer pipe section to the coupling formation and thereby also the housing body.

The inner pipe section may comprise inner coupling formations for coupling each end of the pipe fitting within the housing body to an associated end of the inner pipe section.

The inner coupling formations on the inner pipe section may comprise union couplings. Instead, the inner coupling formations may comprise spigot socket couplings or connections.

The leak sensor must be capable of sensing a liquid and may comprise one or more of an optic sensor, a float sensor, a vibration or an ultrasonic sensor, that is operatively connected to a controller.

The controller may be a PLC controller that receives sensing information from the sensor and communicates this information to a plant operator. In particular, the controller may provide a visual and/or audio indication to a plant operator of the existence of a leak. Conveniently, the controller may include an alarm.

Optionally, the leak sensor may be located proximate to a lowest position along the length of the pipe for early detection of liquid recognising that liquid will flow to a lowest point under the influence of gravity. However, with the piping system disclosed in this application, the leak sensor can be located anywhere because the continuous intermediate space can be pressurised.

The piping system may include a drain for draining liquid from the housing body and/or the intermediate space. In one form, the drain may comprise a drain port with a manually operable valve.

The pipe fitting within the housing space that is operatively coupled to the inner pipe section may take several different forms that perform different functions. In one application of the invention, the pipe fitting within the housing body may comprise a valve operatively coupled in line with the inner pipe section.

In one form, the valve may comprise a shut off valve that is interchangeable between open and closed positions for, respectively, opening and shutting off flow through the inner pipe section. However, it will be readily appreciated that for other applications of the invention, different types of valves may be used.

The housing may have a stem opening formed therein, and the valve may comprise a valve stem passing through the stem opening out of the housing space and a manually operable valve handle at an end of the valve stem for enabling an operator to manually open the valve.

Conveniently, the stem opening may be formed in the top wall of the housing, so the valve handle is positioned above the housing.

Instead of a valve, the pipe fitting within the housing body comprises a pipe junction comprising at least three arms.

The pipe junction may be a T pipe for operatively coupling three pipes or a cross pipe for coupling four pipes.

In yet another form of the invention, instead of a valve or pipe junction, the pipe fitting within the housing body may comprise a meter or gauge for measuring a parameter of the liquid flowing through the inner pipe section.

For example, the pipe fitting within the housing body may comprise a flow meter, a pressure gauge, or a temperature gauge.

In this application of the invention where the pipe fitting is a meter or gauge, the face of the meter or gauge is retained within the housing space and is read by an operator by looking through a transparent inspection zone into the housing space. The face of the meter or gauge does not project out through the housing body.

The inner pipe section may be capable of being pressurised to a pressure above atmospheric pressure.

The continuous intermediate space comprising the intermediate pipe space between the inner and outer pipe sections, and the housing space within the housing, may also be capable of being pressurised. The intermediate space and housing space may be pressurised to a pressure of at least 0.4 bar, e.g. at least 0.5 bar, and optionally also up to about 1 bar.

The inner pipe section may be flexible and capable of bending easily, and the outer pipe section may also be flexible and capable of bending easily. Further, the inner and outer pipe sections are made of a transparent material so that an operator can visually inspect liquid within the inner and outer pipe sections. The flexibility of the pipe helps to avoid the need forjoints, e.g. elbows, along the length of the pipe that can be a source of leaks.

The piping system and the housing may comprise any one or more of the features, or combination of features, in any other aspects of the invention.

According to yet another aspect of the invention there is provided a dual contained piping system comprising: a pipe comprising an inner pipe section and an outer pipe section surrounding the inner pipe section and defining an intermediate pipe space therebetween; a housing body defining a housing space and a plurality of housing ports, each housing port being operatively coupled to the outer pipe section so that the intermediate pipe space and the housing space together form a continuous intermediate space through which liquid can flow, while also receiving the inner pipe section therethrough, wherein the ports of the housing are detachably connected to the outer pipe section so that the housing can be detached from the outer pipe if required; a pipe fitting received in the housing space comprising pipe coupling formations that are operatively connected to the inner pipe section of the piping system, wherein the pipe fitting is detachably connected to the inner pipe section so that it can be removed from the housing space if required; and a leak sensor located in the continuous intermediate space for detecting a leak of liquid out of the inner pipe section or a said pipe fitting at a point along the length of the continuous intermediate space.

The housing and the dual contained piping system may comprise any one or more of the features or combination of features in any other aspect of the invention.

According to another aspect of the invention there is provided a dual contained piping system, comprising: a pipe comprising an inner pipe section and an outer pipe section surrounding the inner pipe section and defining an intermediate pipe space therebetween; a housing body defining a housing space and a plurality of housing ports, each housing port being operatively coupled to the outer pipe section so that the intermediate pipe space and the housing space together form a continuous intermediate space through which liquid can flow, while also receiving the inner pipe section therethrough; and a leak sensor located in the continuous intermediate space for detecting a leak of liquid out of the inner pipe section or a pipe fitting received within the housing fitting, along the length of the continuous intermediate space, e.g. at a point along the length of the space.

According to yet another aspect of the invention there is provided a dual contained piping system comprising: a pipe comprising an inner pipe section and an outer pipe section surrounding the inner pipe section and defining an intermediate pipe space therebetween; a housing body defining a housing space and a plurality of housing ports, each housing port being operatively coupled to the outer pipe section so that the intermediate pipe space and the housing space together form a continuous intermediate space through which liquid can flow, while also receiving the inner pipe section therethrough; a pipe fitting received in the housing space comprising pipe coupling formations that are operatively connected to the inner pipe section of the piping system; and a leak sensor located in the continuous intermediate space for detecting a leak of liquid out of the inner pipe section or a said pipe fitting at a point along the length of the continuous intermediate space, and inner pipe section and pipe fitting operatively connected thereto are pressurised to a pressure above atmospheric pressure, and the single continuous space comprising the intermediate pipe space and the housing space is also pressurised to a pressure above atmospheric pressure.

According to another aspect of this invention there is provided a dual contained piping system comprising: a pipe comprising an inner pipe section and a surrounding outer pipe section; a housing coupled in line with the pipe, wherein the housing is configured to receive a pipe fitting therein that is operatively connected to the inner pipe section, and the housing is operatively connected to the outer pipe section such that it forms a second barrier to leakage when the pipe passes through the housing.

The housing may include housing ports having pipe coupling formations thereon for coupling to complementary pipe coupling formations on the outer pipe section.

The dual contained piping system may include any one or more of the features or combination of features of the piping system defined in any other statements of invention.

The invention extends to a pipe manifold including a dual contained piping system as defined in any preceding aspect of the invention.

The pipe manifold may include any one or more of the optional features or combination of features of the housing or piping system defined in any other aspect of the invention.

The invention extends to a plant installation including a dual contained piping system as defined in any preceding aspect of the invention.

The dual contained piping system may include any one or more of the features or combination of features of the piping system defined in any other aspect of invention.

Similarly, the housing may include any one or more of the features or combination of features of the housing defined in any other aspect of the invention.

in

BRIEF DESCRIPTION OF DRAWINGS

A dual contained or dual walled piping system in accordance with this invention may manifest itself in a variety of forms. It will be convenient to hereinafter describe several embodiments of the invention in detail with reference to the accompanying drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However, it is to be clearly understood that the specific nature of this detailed description does not supersede the generality of the preceding broad description. In the drawings:

Figure 1 is an upper perspective view of a section of a dual contained piping system in accordance with one embodiment of the invention;

Figure 2 is an exploded front view of a section of dual contained piping system like that in Figure 1;

Figure 3 is a cross sectional drawing of an inner and outer pipe section of the dual contained piping system of Figure 2, at a point where the pipe is coupled to the housing;

Figure 4 is an exploded upper perspective view of a dual contained piping system similar to that in Figure 1;

Figure 5 is an upper perspective view of a dual contained piping system in accordance with another embodiment of the invention;

Figure 6 is an exploded upper perspective view of the dual contained piping system in Figure 5;

Figure 7 is an upper perspective view of a dual contained piping system in accordance with yet another embodiment of the invention;

Figure 8 is an exploded upper perspective view of the dual contained piping system in Figure 7;

Figure 9 is an upper perspective view of a dual contained piping system in accordance with another embodiment of the invention;

Figure 10 is an exploded upper perspective view of the dual contained piping system in Figure 9;

Figure 11 is a schematic flow sheet of a manifold of a dual contained piping system in accordance with one embodiment of the invention;

Figure 12 is a diagrammatic sketch of the of the dual contained piping system represented in Figure 11;

Figure 13 is an upper perspective view of one pipe section of the dual contained piping system in Figure 11; and

Figure 14 is an upper perspective view of another pipe section of the dual walled piping system shown in Figure 11.

DETAILED DESCRIPTION

Figures 1 to 4 illustrate a dual contained piping system that is generally in accordance with one embodiment of the invention. In Figures 1 to 4, the dual contained piping system is indicated by the reference numeral 10.

The dual contained piping system 10 comprises a pipe 12 comprising an inner pipe section 14 and a surrounding outer pipe section 16 and defining an intermediate pipe space 17 therebetween. It also includes a housing 20 comprising a housing body defining a housing space 21 that is coupled in line with the pipe 12. Further, the housing 20 has ports 22 and 24 with associated pipe coupling formations on the housing body that are operatively connected to the outer pipe section 16 to operatively connect the housing 20 in series with the outer pipe section 16 and form a second barrier to leakage of liquid out of the pipe 12. The outer pipe section is coupled to the ports 22, 24 in a way that preserves a single continuous intermediate space for liquid flow through the intermediate pipe space 17 and the housing space 21.

The housing 20 has a pipe fitting 30 received therein with clearance that is operatively connected to the inner pipe section 14. In Figures 1 to 4, the pipe fitting 30 is in the form of a ball valve for opening and closing flow of liquid through the inner pipe section 14.

Each of the components of the piping system 10 will now be described in more detail below.

The inner and outer pipe sections 14 and 16 are formed of a flexible and bendable tubular material and preferably the tubular material is also transparent. Conveniently, the flexible tubular material may be formed of a fluoropolymer. The bendable nature of the pipe

11) sections 14 and 16 enables them to accommodate differential expansion due to a temperature difference between liquid in the inner pipe section 14 and air in the outer pipe section 16. The liquid passing through the pipe 12 influences the temperature of the inner pipe section 14, while the external environment including direct sunlight influences the temperature of the outer pipe section 16. This causes differential rates of expansion between the inner and outer pipe sections 14 and 16 and the pipe sections need to be able to accommodate this. The ability of the tubular material forming the pipe 12 to bend easily along its length helps the number of elbows and joins along the length of the pipe system 10 (which are potential points of leakage) to be reduced or eliminated.

Further, the transparent nature of the tubular material permits an operator to visually inspect the intermediate space 17 through the transparent outer pipe section 16 and look for visible signs that liquid has leaked into the intermediate space 17. That is, it directly assists in inspecting for leaks.

The outer pipe section 16 has outer pipe coupling formations 34 at ends thereof that are positioned adjacent the housing and, more specifically, the respective housing ports 22 and 24. The pipe coupling formations 34 are releasably coupling to the ports 22 and 24 on the housing 20. Conveniently, the coupling formations 34 on the outer pipe section 16 and the housing ports 22, 24 respectively comprise male and female formations that engage by means of a screw threaded connection. The structure of this coupling of formations 34 to the ports 22, 24 is illustrated in some detail in Figure 3.

Further, the inner pipe section 14 also has inner pipe coupling formations 36 for releasably coupling the inner pipe section 14 to the pipe fitting 30 received within the housing 20. That is, the coupling formations 36 operatively connect the ends of the inner pipe section 14 to complementary coupling formations on the pipe fitting that is housed within the housing and in this case is a valve 30. The inner coupling formations 36 permit the valve 30 to be detached or separated from the inner pipe section 14, e.g. manually by unclipping or unscrewing the engaged coupling formations 36. Conveniently, the coupling formations 36 on the inner pipe section 14 and the valve 30 are releasably engaged with each other by means of a union connection or a spigot socket attachment. The structure of these coupling formations 36 is illustrated in some detail in Figure 2. Spigot socket and union connections for pipes would be well known to persons skilled in the plumbing arts and accordingly will not be described in greater detail in this detailed description.

The housing 20 comprises a rectangular box that is configured with a sufficient length, width, and height, to receive the pipe fitting 30 therein with a suitable clearance. The housing 20 comprises a bottom wall 40 and a removable top wall 48. The bottom wall, in turn, comprises a base 41 and a side wall 42 extending up from the base 41 around its circumference. The side wall 42 terminates in a terminal upper end having a circumferential mounting flange 46 that projects laterally outward therefrom around its circumference.

The removable top wall 48 is removably mounted on the side wall 42 by means of fasteners 49 that are passed through the top wall 48 and through the mounting flange 46. The mounting flange 46 and the top wall 48 may have a plurality of fastener openings formed therein which can be vertically aligned with each other for receiving the fasteners 49 therethrough. The fasteners 49 may be formed of stainless steel or corrosion resistant polymer to suitably resist corrosion in this environment.

A seal 60, e.g. in the form of a sealing O-ring, is positioned between the top wall 48 and the mounting flange 46 to suitably seal the top wall 48 to the side wall 42. This seal 60 enables the housing 20 and the intermediate space to be pressurised above atmospheric pressure which may be useful in some applications. The O-ring seal 60 is shown most clearly in Figure 4.

The pipe fitting 30 that is a ball valve 30 within the housing 20 comprises a valve body 70 received within the space within the housing 20, and a valve stem or spindle 72, extending up away from the valve body 70. The valve stem 72 passes through a stem opening in the top wall 48 and is sealed to the top wall 48 by means of an O-ring that is recessed in a groove or recess in the top wall. The sealing arrangement enables the housing space 21 can be pressurised to a pressure above atmospheric pressure. The stem 72 extends up to a handle 74 positioned outside the housing 20. The handle 74 is thus accessible to an operator (outside of the dual containment structure and environment) who may manually turn the valve handle 74, to open and close the valve 30 and thereby open and close flow through the inner pipe section 14.

The piping system 10 includes a leak sensor (not shown) within the housing 20 for sensing a leak from the inner pipe section 14 into the outer pipe section 16 or the housing space 21. Conveniently, the leak sensor which may take a variety of forms including optic sensor, float sensor, vibration sensor or ultrasonic sensor is positioned at a low point of the housing 20. The leak sensor may be operatively coupled to a leak condition indicator, that typically comprises a controller, e.g. including a PLC, for communicating

IA a leak to a plant operator. The leak condition communicator may further comprise an alarm, e.g. a visual and/or audio alarm.

The intermediate pipe space 17 within the outer pipe section 16, and the housing space 21 formed in the interior of the housing 20, are interconnected and open into each other to form a single discrete continuous intermediate space along their combined length. This enables a single sensor arrangement to detect a leakage at any point along the length of the pipe. This removes the need to duplicate leak detection sensors along the length of the pipe 12. This is advantageous to operators because each sensor requires its own PLC and electronics system and the duplication of these systems at several points along the pipe 12 adds significantly to the cost of a dual contained piping installation. Applicant has noted that plant operators strive to avoid the need to duplicate leak detection sensors.

The housing 20 may optionally further include a drain in the form of a drain port (not shown) for draining liquid from the interior space of the housing 20. The drain port, in turn, may include a drain cock or tap for enabling an operator to drain liquid from the housing space 21 within the housing 20 in a controlled manner.

The housing 20 further includes an inspection port 82 in the top wall 48 of the housing 20 for enabling an operator to visually inspect the housing 20 for leaks, i.e. from the inner pipe section 14 and the valve 30 into the intermediate pipe space 17 and the interior housing space 21 of the housing 20.

The inspection port 82 may be provided in several different ways. In the embodiment illustrated in Figure 1, the inspection port 82 is provided by having a transparent top wall 48 of the housing 20. However, it will be appreciated that there are many other ways of providing an inspection port having these capabilities. For example, in the embodiments in Figures 3 and 4, the inspection port may be in the form of one or two small windows in the top wall 48.

Figures 11 and 12 illustrate one example embodiment or layout of a manifold for a piping system 10 in accordance with one embodiment of the invention. The overall layout of the piping system 10 in Figures 11 and 12 will be described below.

The piping system 10 commences (on the left side) with a transition from a single pipe to a dual contained pipe 12 which is indicated by A in the drawings. This is basically the entry point to the dual containment manifold and marks the starting point or initial point

IF of the dual containment. The transition A contains a valve 30 received within a housing 20 like the arrangement shown in Figures 1 to 4.

The dual contained pipe 12 with inner and outer pipe sections 14 and 16 then progress to a pipe fitting 30 indicated by C in the drawings having a T piece like that described above with reference to Figures 5 and 6. The pipe fitting 30 permits a branch pipe to branch off the main pipe 12 while it is still retained in a dual contained environment. The branch pipe leads to a drain for draining to an external environment which is indicated by reference letter B. The drain B could be used for draining liquid from the inner pipe section 14. The drain B could also be used for draining liquid from the intermediate pipe space 17. The arrangement shown at B effectively provides a transition from the dual contained pipe to a single pipe.

The piping system 10 then leads from the T piece arrangement indicated by C to a valve such as a ball valve which is indicated by the reference letter E. This arrangement is similar to that described above with reference to Figures 1 to 4. The valve E is received within a housing 20 providing an outer containment. The valve E has a valve stem 72 projecting up through the housing 20 and a manual valve handle 74 external to the housing 20. The handle 74 can be manually operated by an operator to open and close the valve E. This arrangement is similar to the valve and housing described above, with reference to Figures 1 to 4.

Yet further, the piping system 10 has a further pipe fitting at the end of the pipe 12 that is indicated by reference letter D. The pipe fitting D is placed at a downstream end of the section of pipe 12 and transitions the manifold back down from dual pipe containment down to single pipe containment. The outer pipe section 16 upstream of the pipe fitting D is coupled to an outer coupling formation 34 on the pipe fitting D where it transitions to form a single pipe 12 without a second barrier against leakage.

In the dual containment pipe manifold shown in Figures 11 and 12, the intermediate pipe space 17 together with the interior housing spaces 21 of the housings 20 coupled in line with the pipe 12 comprises a single and continuous intermediate space along its full length that is open to fluid flow and fluid communication. This removes the need for duplication of leak sensing equipment with its attendant additional expense. A leak out of the inner pipe section 14 at any point along the pipe 12 can be detected by a single leak sensor. Accordingly, if there is a leak along the length of the pipe manifold, it can be picked up a leak detector positioned anywhere along the pipe.

Further, the single and continuous intermediate space for liquid flow comprising the intermediate pipe space and the housing spaces can be pressurised in use. For example, these spaces can be pressurised to a pressure of at least 0.4. bar above atmospheric pressure, preferably above 0.5 bar above atmospheric pressure, and in some applications up to about 1 bar.

In use, the dual piping system 10 is used to transfer liquid, e.g. a hazardous liquid such as acid or alkali, from one point to another, e.g. from a storage site to a liquid utilisation site. The liquid is passed through the inner pipe section 14 and through the valve housing 70. At each point along the system 10 including where there are valves, flow meters, pressure gauges, temperature gauges, and pipe junctions such as T pieces and cross pieces, the piping system 10 provides dual containment. In the region of the housing 20, the housing 20 itself provides a second layer of containment which captures any leakage out of the valves 30, flow meters, pressure gauges, T pieces and/or connections with the inner pipe section 14 in this region of the piping system 10.

During operation of the piping system 10, an operator can visually inspect for leakage into the interior space of the housing 20. They do this by removing the caps over the transparent inspection plates 82, e.g. windows, to expose the plates for inspection. Further, the leak condition communicator receiving sensing information from the sensor also notifies a plant operator when it senses a leak. Once a leak has been identified, remedial action can be taken to repair the leak and importantly, the leak is contained so that the liquid does not escape into the surrounding environment.

Figures 5 and 6 illustrate part of a dual wall piping assembly in accordance with another embodiment of the invention. Unless otherwise indicated, the same reference numerals will be used to refer to the same components.

In Figures 5 and 6, the housing 20 is constructed to receive and house a pipe fitting 30 that is a T piece pipe junction that has three pipe branches 30A, 30B and 30C that are in communication with each other. Typically, this T piece is used where two feed liquid streams are combined or merged into a single liquid stream that then progresses along the pipe 12. However, the T piece can also be used to divide a single liquid stream into two different streams.

The housing 20 has a sufficient height to receive the T piece pipe fitting 30 therein with some clearance. In addition to the housing ports 22, 24 described above with reference to Figures 1 to 5, the housing 20 also has a further port 88 with a coupling formation for coupling to the outer pipe section 16 of an associated pipe. This has a very similar structure and function to the pipe coupling formations of the ports 22, 24 described above with reference to Figures 1 to 4, and to Figure 3 in particular.

As illustrated in the drawing, the housing 20 does not have a stem or spindle 72 projecting through its top wall 48. It does, however, have an inspection port 82 covered by a cap for enabling an operator to inspect the housing space within the interior of the housing 20.

In use, the piping assembly in Figures 5 and 6 operates in similarfashion to the assembly 10 described above with reference to Figures 1 to 4.

Figures 7 and 8 illustrate a variation on the embodiment shown in Figures 1 to 4 that has a housing 20 that receives a fitting 30 that is a valve such as a ball valve therein. Unless otherwise indicated, the same reference numerals will be used to refer to the same components as in the earlier embodiments.

In this embodiment, the housing 20 has a circular configuration and is sized with a radius that is sufficiently large to receive the valve 30 therein with some clearance. The spindle 72 projects through the top wall 48 of the housing 20. Other than the different shape of the housing 20, the structure and function of the inner and outer pipe sections 14 and 16 and their couplings to the valve 30 and housing 20 respectively, and the other components, are very similar to that described above with reference to Figures 1 to 4.

In use, the piping assembly in Figures 7 and 8 operates in similarfashion to the assembly 10 described above with reference to Figures 1 to 4.

Figures 9 and 10 illustrate a variation on the embodiment shown in Figures 5 and 6 that has a housing 20 that is configured to receive a pipe fitting that is a T piece 30 having three pipe branches namely 30A, 30B and 30C. Unless otherwise indicated, the same reference numerals will be used to refer to the same components as in the earlier embodiments.

In this embodiment, the housing 20 has a circular configuration and is configured with a radius that is sufficiently large to receive the valve 30 therein with some clearance. Other than the different shape of the housing 20, the structure and function of the piping system 10 and the components thereof is very similar to that described above with reference to Figures 5 and 6.

In use, the piping assembly in Figures 9 and 10 operates in similar fashion to the assembly 10 described above with reference to Figures 5 and 6.

Figures 13 and 14 illustrate some pipe sections for use in the piping system illustrated in the drawings and in particular the manifold illustrated in Figure 12.

The pipe section in Figure 13 illustrates the branch extending downward away from pipe fitting C in more detail. The pipe section has a drain point branching off from the main pipe.

The pipe section in Figure 14 illustrates the pipe fitting D at the end of the manifold that performs a dual to single pipe transition in more detail. The main difference between the pipe section in Figure 14 over that in Figure 13 is that it does not have a drain.

Some of the working advantages of the dual walled piping system described above with reference to the drawings will now be described below.

An advantage of the dual walled piping system described above with reference to the drawings is that it provides a complete dual contained system for conveying corrosive chemicals that extends from one location to another. A point or region along the path of the piping assembly where there is only a single containment provides a point of weakness within the system at which liquid can leak out of the pipe into the external environment. This situation poses some risks and, strictly speaking, bunding or civils containment should be provided to deal with this situation. However, with the dual piping assembly described above, there are no regions or points along the length of the pipe that provide only a single layer of containment. There is a dual barrier or a dual wall at every point along the length of the pipeline. This therefore dramatically improves safety and helps to meet the workplace safety standards.

Another advantage of the dual piping system described above is the housing that is operatively coupled to the pipe and provides for dual containment at points along the pipe where there are valves, or gauges or tee junctions. These points along the pipe are known to be difficult points at which to provide dual wall protection and the housing enables this dual protection to be provided.

The housing has a number of features that contribute to its working advantage. The housing has an inspection port that enables an operator to inspect for leaks. Further, the housing also has a drain that enables a user to drain liquid from the housing that has leaked into the housing from the inner pipe section. Additionally, the housing can be disassembled for maintenance and the like. In particular, as described above, the top wall can be removed by removing the fasteners, e.g. mounting bolts, passing through the mounting flanges to lift the top wall off the side wall and opening up the housing.

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Another advantage of the dual piping system described above having the ball valve is that the ball valve is operable from outside of the housing. The stem and handle of the valve projects through the wall of the housing. This therefore preserves a dual wall barrier between an operator, and liquid within the inner pipe section, while an operator can still manually operate the valve. There is no compromise of the dual layer protection afforded to the operator when they are operating the valve.

Another advantage of the dual piping system described above is that the pipe is flexible along its length. Both the inner and outer pipe sections are flexible along their length and in addition to the flexibility being easy to work with it confers other advantages. For example, pipe elbows and the associated pipe joins that are a source of leaks can be avoided. The liquid within the inner pipe section is typically at a lower temperature than the external environment which might, for example, be in the sun. Thus, the inner pipe section is typically at a lower temperature than the outer pipe section and this causes differential expansion across the two sections. The flexible pipe used by the Applicant can accommodate this differential expansion without cracking or other adverse effect.

Another advantage of the dual piping system described above is that the components are manufactured of corrosion resistant thermoplastic materials with no wetted metallic components. The materials for the pipe and the housing are selected to be suitable for use with the material that will be transported through the pipes.

Another advantage of the dual piping system described above is that it has a single intermediate space along the length of the pipe including the housing. The intermediate space does not comprise a plurality of discrete compartments along its length. Consequently, it requires only one leak detection system along the length of the manifold. If the piping assembly had multiple intermediate compartments long its length, this would add considerably to the complexity and cost of the system. Applicant also believes it would be more unwieldy to use and operate.

Another advantage of the dual piping system described above is that the piping system can be fully disassembled to open up the piping system to expose the inner pipe section. This is useful for maintenance of the system and avoids the need to cut through components which then need to be repaired. Further, the components making up the inner pipe section and the attached to the inner pipe section are detachably connected to each other so that they can be repaired or replaced as required without cutting through pipes and joins.

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Yet another advantage of the dual piping system described above is that the intermediate space and connected housing space of the piping system can be pressurised to a pressure above atmospheric pressure. This assists in displacing liquid through an outlet to remove it from the intermediate space.

It will of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of the invention as is herein set forth.

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Claims

CLAIMS:

1. A housing for coupling in line with a dual contained piping system comprising a pipe having an inner pipe section and a surrounding outer pipe section forming an intermediate pipe space between the inner and outer pipe sections, the housing comprising: a housing body defining a housing space that is configured to receive a pipe fitting therein for operatively connecting the pipe fitting to the inner pipe section of the piping system, wherein the housing comprises a plurality of housing ports for operatively and removably connecting the housing ports to the outer pipe section, and the housing ports are configured to be operatively connected to the outer pipe section such that the intermediate pipe space and the housing space together form a continuous intermediate space through which liquid can flow, while the housing ports also receive the inner pipe section therethrough.

2. A housing according to claim 1, including a leak sensor for detecting liquids within the housing space to indicate that a leak exists in the piping system.

3. A housing according to claim 1 or claim 2, wherein the housing body comprises a removable closure that can be removable to provide access to the housing space within the housing body for performing maintenance.

4. A housing according to claim 3, wherein the container body comprises a bottom wall and a top wall, and the top wall forms the removable closure.

5. A housing according to claim 4, wherein and the removable top wall is mounted on the container by means of complementary flanges on each of the top wall and the container body, and fasteners fastening the flanges to each other.

6. A housing according to claim 4 or claim 5, wherein the housing comprises a transparent inspection zone formed in the removable closure for facilitating inspection of the housing space, and the transparent inspection zone comprises at least one sight glass underneath a removable cover that can be removed for the purposes of inspection.

7. A housing according to claim 6, wherein the transparent inspection zone comprises two transparent inspection plates, wherein one transparent inspection plate is for admitting light into the container body and the other transparent inspection plate is for visually inspecting the housing space.

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8. A housing according to any one of claims 1 to 7, wherein the housing body has a stem opening formed therein for receiving a stem of a pipe fitting there through to enable the pipe fitting to be manually operable from outside of the housing space.

9. A housing according to any one of claims 1 to 8, that is configured and designed to enable the housing space to be pressurised when connected to a pipe and forming part of a dual contained piping system.

10. A dual contained piping system comprising: a pipe comprising an inner pipe section and an outer pipe section surrounding the inner pipe section, and defining an intermediate pipe space therebetween; a housing body defining a housing space and a plurality of housing ports, each housing port being operatively coupled to the outer pipe section so that the intermediate pipe space and the housing space together form a continuous intermediate space through which liquid can flow, while also receiving the inner pipe section therethrough; a pipe fitting received in the housing space comprising pipe coupling formations that are operatively connected to the inner pipe section of the piping system; and a leak sensor located in the continuous intermediate space for detecting a leak of liquid out of the inner pipe section or a said pipe fitting at a point along the length of the continuous intermediate space.

11. A dual contained piping system according to claim 10, wherein the outer pipe section has ends releasably coupled to the housing ports so that the outer pipe section can be disconnected from the housing ports.

12. A dual contained piping system according to claim 11, wherein each housing port comprises an outer pipe coupling formation releasably coupled to a complementary outer pipe coupling formation on the outer pipe section.

13. A dual contained piping system according to claim 12, wherein the outer pipe coupling formation on the housing port comprises a female formation and the complementary outer pipe coupling formation on the outer pipe section comprises a male formation.

14. A dual contained piping system according to claim 12 or claim 13, wherein the complementary pipe coupling formation on the outer pipe section further comprises a clamping nut for clamping the male formation onto the outer pipe whereby to seal the outer pipe section to the coupling formation and thereby also the housing body.

15. A dual contained piping system according to any one of claims 10 to 14, wherein the inner pipe section comprises inner coupling formations for releasably coupling the pipe fitting within the housing body to the inner pipe section.

16. A dual contained piping system according to claim 15, wherein the inner coupling formations comprise union couplings.

17. A dual contained piping system according to any one of claims 10 to 16, wherein the leak sensor comprises a sensor capable of sensing a liquid that is operatively connected to a controller, which then communicates the leak to an operator, and including a drain for draining liquid from the continuous intermediate space formed by the housing space and the intermediate pipe space.

18. A dual contained piping system according to any one of claims 10 to 17, wherein the pipe fitting within the housing body comprises a valve operatively coupled in line with the inner pipe section.

19. A dual contained piping system according to claim 18, wherein the valve is interchangeable between open and closed positions for respectively, opening and shutting off, flow through the inner pipe section, and the valve comprises a valve stem that projects out of the housing body and a valve handle outside of the housing body.

20. A dual contained piping system according to any one of claims 10 to 17, wherein the pipe fitting within the housing body comprises a flow meter or a pressure gauge or a temperature gauge.

21. A dual contained piping system according to any one of claims 10 to 20, wherein the inner pipe section is capable of being pressurised to a pressure above atmospheric pressure, and wherein the intermediate pipe space between the inner and outer pipe sections and the housing space within the housing body is also capable of being pressurised.

22. A dual contained piping system according to any one of claims 10 to 21, wherein the inner pipe section is flexible, and the outer pipe section is also flexible, and the inner and outer pipe sections are made of a transparent material so that an operator can visually inspect liquid within the inner and outer pipe sections.

23. A dual contained piping system comprising: a pipe comprising an inner pipe section and an outer pipe section surrounding the inner pipe section and defining an intermediate pipe space therebetween; a housing body defining a housing space and a plurality of housing ports, each housing port being operatively coupled to the outer pipe section so that the intermediate pipe space and the housing space together form a continuous intermediate space through which liquid can flow, while also receiving the inner pipe section therethrough, wherein the ports of the housing are detachably connected to the outer pipe section so that the housing can be detached from the outer pipe if required; a pipe fitting received in the housing space comprising pipe coupling formations that are releasably connected to the inner pipe section of the piping system, whereby the pipe fitting is detachably connected to the inner pipe section so that it can be removed from the housing space for maintenance or replacement if required; and a leak sensor located in the continuous intermediate space for detecting a leak of liquid out of the inner pipe section or a said pipe fitting at a point along the length of the continuous intermediate space.

24. A dual contained piping system comprising: a pipe comprising an inner pipe section and an outer pipe section surrounding the inner pipe section and defining an intermediate pipe space therebetween; a housing body defining a housing space and a plurality of housing ports, each housing port being operatively coupled to the outer pipe section so that the intermediate pipe space and the housing space together form a continuous intermediate space through which liquid can flow, while also receiving the inner pipe section therethrough; a pipe fitting received in the housing space comprising pipe coupling formations that are operatively connected to the inner pipe section of the piping system; and a leak sensor located in the continuous intermediate space for detecting a leak of liquid out of the inner pipe section or a said pipe fitting at a point along the length of the continuous intermediate space, and the inner pipe section and pipe fitting operatively connected thereto is pressurised to a pressure above atmospheric pressure, and the continuous intermediate space comprising the intermediate pipe space and the housing space is also pressurised to a pressure above atmospheric pressure.