WO2012072812A1

WO2012072812A1 - Leak detection system

Info

Publication number: WO2012072812A1
Application number: PCT/EP2011/071672
Authority: WO
Inventors: Burghard Brink
Original assignee: Emstec & Co KG GmbH
Current assignee: Emstec & Co KG GmbH
Priority date: 2010-12-03
Filing date: 2011-12-02
Publication date: 2012-06-07
Anticipated expiration: 2013-06-03
Also published as: GB201020506D0

Abstract

The present invention relates to leak detections systems, especially those for use in relation to tubing, hosing and/or piping, especially marine applications thereof, and for methods of detecting leaks. The leak detections systems in one aspect include a signal line connected to a gauge, and at least one signal line control device, the signal line control device being actuated by a leakage within a system being monitored. The leak detection systems may also include in a second aspect a detection substance reservoir, and a detection substance control device being actuated by a leakage within a system being monitored. The leak detection systems may also include in a third aspect a piston and cylinder arrangement, and a casing around part of said piston and cylinder arrangement, said casing having a clear portion. The methods comprise in a first aspect the steps of linking a detection substance supply to a primary fluid supply, such that leakage of the primary fluid supply affects a physical characteristic of the detection substance supply, and monitoring said physical characteristic of said detection substance supply. The methods comprise in a second aspect the steps of linking a detection substance supply to a primary fluid supply, such that leakage of the primary fluid supply causes leakage of the detection substance supply, and monitoring said detection substance leakage. The present invention relates to leak detections systems, especially those for use in relation to tubing, hosing and/or piping, especially marine applications thereof, and for methods of detecting leaks. The leak detections systems in one aspect include a signal line connected to a gauge, and at least one signal line control device, the signal line control device being actuated by a leakage within a system being monitored. The leak detection systems may also include in a second aspect a detection substance reservoir, and a detection substance control device being actuated by a leakage within a system being monitored. The leak detection systems may also include in a third aspect a piston and cylinder arrangement, and a casing around part of said piston and cylinder arrangement, said casing having a clear portion. The methods comprise in a first aspect the steps of linking a detection substance supply to a primary fluid supply, such that leakage of the primary fluid supply affects a physical characteristic of the detection substance supply, and monitoring said physical characteristic of said detection substance supply. The methods comprise in a second aspect the steps of linking a detection substance supply to a primary fluid supply, such that leakage of the primary fluid supply causes leakage of the detection substance supply, and monitoring said detection substance leakage.

Description

LEAK DETECTION SYSTEM

Description

Field of the Invention

The present invention relates to leak detections systems, especially those for use in relation to tubing, hosing and/or piping, especially marine applications thereof.

Background of the Invention

Leak detection is an important, and often legally mandated, aspect in the transport of fluids, especially when the leakage of such fluids can be hazardous. One important example is the transport of hydrocarbons, where leakage of crude oil may be dangerous and have a very negative environmental impact. Hoses used for the transport of hydrocarbons may be single or double carcass. Double carcass hoses are effectively a first hose disposed within a second hose. Leakages from the first hose should be contained by the second hose, but should such a leakage occur, there may be no visual indication that such a leakage is in progress unless a leak detection system is fitted to notify the operator of the hose.

Several prior art systems exist. A common one is a simple piston and cylinder arrangement. The cylinder is in fluid communication with the secondary carcass and should a leakage occur and begin to fill the secondary carcass, the leaked fluid will eventually fill the cylinder and force the piston outward. The piston may include a simple projection from its distal end, and as the cylinder fills and forces the piston outward, the projection is arranged such that it will extend from the secondary carcass, such that it will be visually obvious that leakage is occurring if the projection is visible from its location on the secondary carcass.

A simple valve may also be located on the second carcass, and allow an operator to check whether a leak is occurring by simply opening the valve. Should the fluid be leaking into the second carcass, it should also exit the valve.

These systems are not without their drawbacks. The valve system has to be actively monitored, and the piston system may not be entirely obvious from distance, needing a close visual inspection of each carcass, which may be time consuming.

Summary of the Invention

According to a first aspect of the present invention there is provided a leak detection system comprising a signal line connected to a gauge, and at least one signal line control device, the signal line control device being actuated by a leakage within a system being monitored.

The signal line may be a fluid line, with the signal line control device being a fluid line control device and the gauge being a pressure gauge.

Thus, a leakage causes a physical characteristic of the signal line to change, and that change will be detected by the gauge. This may be the pressure of a fluid within the signal line, but may also be an electrical or optical signal that is altered. To aid in this, the fluid line may be pressurised i.e. it may be at a pressure above or below the surrounding environmental pressure. The pressure gauge may be mechanical or electronic, and may be further connected to control systems to shut down or otherwise control the system which the present invention is monitoring.

The fluid line control device may itself cause leakage within the fluid line such that the detection fluid within said fluid line leaks from the system.

The fluid line may be filled with any suitable detection fluid, but

advantageously may employ a detection fluid with an enhanced visual appearance, such that leakage of said detection fluid provides an obvious indication of a leakage within a fluid supply system being monitored. Such an enhanced visual appearance may preferably contrast with the environment in which the system is located, and may be a luminescent detection fluid. The fluid line control device may comprise a cylinder and piston

arrangement, the cylinder and piston arrangement being actuated by a leakage within a system being monitored.

The fluid line may have a section that passes through said cylinder and piston arrangement. This section may branch off from, or form a junction with, a primary section of the fluid line, and the piston and cylinder arrangement may initially hold this section closed, but when actuated may vent this section to the environment in which the system is located. The cylinder and piston may be mechanically connected to a valve upon the fluid line, and that valve may be a simple removable section within the supply line. For example a T-Connector may be employed, with the two parallel sections of the T-Connector attaching and forming part of the fluid line, and the perpendicular branch of the T-Connector being mechanically connected to the cylinder and piston arrangement.

Thus when a leakage occurs in the system being monitored, the fluid line control device actuates to break the fluid line, altering the pressure therein and allowing leakage of the detection fluid. A pressure drop and visual indication of a leakage are then provided.

As a further advantage, the position of the cylinder and piston

arrangement provides a further visual indication of leakage.

In a double carcass hose system, the leak detection system may be arranged such that the piston and cylinder device are mounted upon the secondary carcass and are actuated by fluid leaking into the secondary carcass. Such double carcass hose systems usually have mating faces, most likely cooperable flanges, and advantageously the fluid line control device is located near or adjacent a flange

The leak detection system may include two (or more) fluid lines, and fluid line control devices on adjacent hose sections on either side of connected flanges may connect to different fluid lines; thus, redundancy is provided for in the system. The two fluid lines may connect with one another, perhaps at a furthest extent of a system being monitored. A single pressure gauge may monitor both lines, or a pressure gauge may be provided per fluid line. Independent monitoring of the two lines may provide a further indication of where leakage may be occurring. The fluid line or fluid lines may be helically wound around a system being monitored, especially if the system is largely an elongate arrangement with a substantially circular cross-section.

According to a second aspect of the present invention there is provided a leak detection system comprising a detection substance reservoir, and a detection substance control device being actuated by a leakage within a system being monitored.

Thus, a leakage causes the detection substance control device to transport a detection substance out of the detection substance reservoir. The detection substance may be simply vented to outside the leak detection system, or a monitoring chamber may be provided.

The detection substance may have an enhanced visual appearance, such that leakage of said detection substance provides an obvious indication of a leakage within a fluid supply system being monitored. Such an enhanced visual appearance may preferably contrast with the environment in which the system is located, and may be a luminescent detection substance.

The detection substance may be a fluid, especially a liquid. The detection substance reservoir may be in the form of a fluid line, and the fluid line may be pressurised i.e. it may be at a pressure above or below the surrounding environmental pressure. Additionally, a pressure gauge or gauges may be employed to monitor pressure within the detection substance reservoir, and provide an additional indication of leakage by monitoring a pressure change. The detection substance control device may comprise a cylinder and piston arrangement, the cylinder and piston arrangement being actuated by a leakage within a system being monitored.

There may be a fluid line that connects to the detection substance reservoir and has a section that passes through said cylinder and piston arrangement. This section may branch off from, or form a junction with, a primary section of the fluid line, and the piston and cylinder arrangement may initially hold this section closed, but when actuated may vent this section to the environment in which the system is located.

The cylinder and piston may be mechanically connected to a valve upon the detection substance reservoir, and that valve may be a simple removable section within the detection substance reservoir. For example a T-Connector may be employed, with the two parallel sections of the T- Connector attaching and forming part of the detection fluid reservoir, and the perpendicular branch of the T-Connector being mechanically connected to the cylinder and piston arrangement.

Thus when a leakage occurs in the system being monitored, the detection substance control device actuates to form an opening in the detection substance reservoir and allowing leakage of the detection fluid. As a further advantage, the position of the cylinder and piston

arrangement may provide a further visual indication of leakage.

In a double carcass hose system, the leak detection system may be arranged such that the piston and cylinder device are mounted upon the secondary carcass and are actuated by fluid leaking into the secondary carcass. Such double carcass hose systems usually have mating faces, most likely cooperable flanges, and advantageously the detection substance reservoir is located near or adjacent a flange The leak detection system may include two (or more) detection substance reservoirs, detection substance control devices on adjacent hose sections on either side of connected flanges may connect to different fluid lines; thus, redundancy is provided for in the system. The two detection substance reservoirs may connect with one another, perhaps at a furthest extent of a system being monitored.

The detection fluid reservoir(s) may be helically wound around a system being monitored, especially if the system is largely an elongate

arrangement with a substantially circular cross-section.

According to a third aspect of the present invention there is provided a leak detection system comprising a piston and cylinder arrangement, and a casing around part of said piston and cylinder arrangement, said casing having a clear portion.

Preferably the casing encloses an extending portion of said piston and cylinder arrangement. This part would otherwise extend simply into the environment in which the system being monitored was located. The casing allows for the detection system to be viewed via the clear portion and also protected from harsh environmental conditions.

According to a fourth aspect of the present invention there is provided a leak detection system comprising at least two leak detection systems according to the first, second or third aspects. According to a fifth aspect of the present invention there is provided a fluid system including at least one leak detection system according to the first, second, third or fourth aspects. According to a sixth aspect of the present invention there is provided an oilfield including at least one leak detection system according to the first, second, third or fourth aspects or a fluid system according to the fifth aspect. According to a seventh aspect of the present invention there is provided a method of detecting a leak comprising the steps of linking a detection substance supply to a primary fluid supply, such that leakage of the primary fluid supply affects a physical characteristic of the detection substance supply, and monitoring said physical characteristic of said detection substance supply.

This may be the pressure of the detection substance supply, such that a leak of the primary fluid supply causes a pressure change in the detection substance supply.

The detection substance supply is preferably linked to the primary fluid supply by a cylinder and piston arrangement.

A detection substance within the detection substance supply may have an enhanced visual appearance, one that contrasts with the environment in which a system being monitored is located.

The method may include transporting the detection substance to an area that may be visually monitored by a user, for example outside of a system being monitored and into an adjacent area. According to an eighth aspect of the present invention there is provided a method of detecting a leak comprising the steps of linking a detection substance supply to a primary fluid supply, such that leakage of the primary fluid supply causes leakage of the detection substance supply, and monitoring said detection substance leakage.

Preferably a detection fluid used in said detection substance supply has an enhanced visual appearance, preferably one that contrasts with the surrounding environment, preferably a luminous detection substance.

The substance may be a fluid, including a liquid.

Brief Description of the Drawings

An embodiment of the invention will now be described, by way of example only, with reference to the following drawings in which:

Fig. 1 is a diagrammatic side view of a leak detection system according to the present invention;

Fig. 2 is a diagrammatic side view of a pipe-line comprising sections of hosing and leak detection systems of Fig. 1 ; Fig. 3 is a plan view of the piston and cylinder arrangement of the leak detection system of Fig. 1 in a normal working condition;

Fig. 4 is a sectional side view on of the piston and cylinder indicator of Fig. 3; Fig. 5 is a plan view of the piston and cylinder indicator of the leak detection system of Fig. 1 in an activated condition;

Fig. 6 is a sectional side view of the piston and cylinder indicator of Fig. 5;

Fig. 7 is diagrammatic side view of an alternative leak detection system according to the present invention; Fig. 8 is a diagrammatic side view of a pipe-line comprising sections of hosing and leak detection systems of Fig. 1 ; and

Figs. 9 to 1 1 are various views of an alternative leak detection system according to the present invention.

Turning first to Fig 1 , a leak detection system 10 is shown mounted between a first or left hand double carcass hose section 100, and a second or right hand double carcass hose section 102. The two hose sections 100, 102 are mounted via respective flanges 100a, 102a.

The leak detection system 10 comprises a fluid line 12 which spans the two hose sections 100, 102. The fluid line 12 has two T-Connectors 14 at intermediary points along its length. On each of the two hose sections, adjacent the respective flanges 100a, 102a are provided two piston and cylinder indicators 16. These operate in a known manner: the cylinder is in fluid communication with the secondary carcasses 100b, 102b of the respective hose sections 100,102 such that any leakage from the primary carcasses 100c, 102c to the secondary carcasses 100b, 102b causes the pistons 16a to extend or retract. Tethers 15 form a mechanical and fluid connection between the T- Connectors 14 and the piston and cylinder indicators 16.

In this particular embodiment, Fig. 1 shows a normal working condition, where leakage is not occurring, and consequently the fluid line 12 and T- Connectors 14 form a continuous and unbroken fluid path.

The fluid line 12 also defines a substance reservoir, and within the fluid line 12 there is a detection substance, the substance being a fluid (not shown). The detection fluid in this embodiment is supplied at a pressure of 5 Bar, although it will be understood that the particular pressure employed may be modified depending on the particular application and pressure of the surrounding environment. The detection fluid in this embodiment is also highly visible, being a luminous fluid. Leakage of this detection fluid into, for example, a body of water within which the system being monitored is located will be more apparent to an observer. Turning to Fig. 2, it can be seen that multiple hose sections are connected to form a hose line 104, with the leak detection system 10 spanning the entire hose line 104. The fluid line 12 is connected to a combined pump and pressure gauge 18. This combined pump and pressure gauge 18 supplies the luminous detection fluid at a pressure of 5 Bar and monitors the pressure within the fluid line 12. The hose line 104 is in this embodiment transporting crude oil (not shown).

In use, the fluid line 12 is charged at 5 Bar and the pressure is monitored by the combined pump and pressure gauge 18. Fig. 3 & 4 show detail of the piston and cylinder indicators in the normal working condition. The piston 16a is disposed within the cylinder 16b. A spring 16c biases the piston 16a to the open position. The piston has an upper central bore 16d in which the spring 16c is seated, and around its outer surface 16e (the surface in sliding contact with the inner surface 16f of the cylinder) are three seal channels 16g running circumferentially around the outer surface 16e. They are approximately equal in depth and height, such that a substantially square channel is formed. Within each of these seal channels 16g is a rubber ring seal 16h.

A further fluid channel 16i is provided around the outer surface 16e of the piston 16a. It is located with one seal channel 16g / seal 16h arrangement on one side of it, and two seal channel 16g / seal 16h arrangements on the other side of it. It is shallower than the seal channels i.e. it does not penetrate as far into the outer surface 16e of the piston 16a, but it is of a greater height.

Running radially through the thickness of the cylinder 16b, approximately halfway along its length, is a tether inlet aperture 16j. The tether 15 is attached to this, although it has been omitted from these Figs for clarity. Pressurised fluid from the fluid line 12 is therefore in fluid communication with the fluid channel 16i, but in this configuration, the fluid channel is sealed, by a combination of its position within the cylinder 16b and the seals 16h.

A fluid outlet aperture 16k is provided radially through the thickness of the cylinder 16b. It provides a fluid path through the thickness of the cylinder 16b, from the external environment to the junction of the inner surface 16f of the cylinder 16b and the outer surface 16c of the piston 16a. In the Fig. 4 position, it is positioned between the two upstream seals 16h, and thus the fluid communication is blocked.

Should a leakage occur in the primary carcass of one of the sections of the hose line 104 (for example in hose section 100), the transported crude oil will begin to fill the secondary carcass 100b and in turn the cylinder 16b. This in turn will cause the outward movement of the piston 16a.

Figs 5 and 6 show details of this. Oil filling the secondary carcasses 100b/100c will act against the lower surface 16m (the right hand side of Fig. 5) of the piston 16a. This will act against the biasing force of the spring 16c compressing it against the cylinder 16b.

The fluid channel 16i will move upwardly (toward the left hand side of Fig.5), maintaining fluid communication with tether inlet aperture 16j and therefore a pressurised fluid supply.

Eventually, the fluid channel 16i will be in the position shown in Fig. 5, and will provide a fluid pathway from the tether 15 through to the fluid outlet aperture 16k. Thus, pressurised indicator fluid will appear from the fluid outlet aperture 16k providing a visual indication of leakage and further, would result in a pressure drop within the system which is detected by the combined pump and pressure gauge 18. This outward movement of the piston 16a pulls and may also cause displacement of the tether 15, and eventually also the T-Connector 14. The T-Connectors 14 may be joined to the fluid line 12 through breakable junctions 14a. These breakable junctions 14a would be designed to withstand the internal 5 Bar pressure, but may be broken by the action of piston 16a and tether 15. The tether 15, in this modification, pulls and displaces the T-Connector 14 out of the fluid line 12 causing indicator fluid to leak from the fluid line 12. This again has two effects: first, there is a measureable pressure drop within the system which is detected by the combined pump and pressure gauge 18 and second, the indicator fluid being a highly visible substance provides a visual indication of the section 100 where the leak is occurring.

An alarm signal is emitted by the combined pump and pressure gauge 18, and this may simply alert an operator of a leakage by actuation of an audio and/or visual alarm, or may be used to automatically cease flow within the hose line 104.

Figs. 7 and 8 depict an alternative embodiment of the present invention. A leak detection system 20 is shown mounted between a first or left hand double carcass hose section 200, and a second or right hand double carcass hose section 202. The two hose sections 200,202 are mounted via respective flanges 200a,202a. The leak detection system 20 comprises two fluid lines 22a, 22b which span the two hose sections 200,202. The two fluid lines 22a, 22b have two T-Connectors 24 at intermediary points along their length. On each of the two hose sections, adjacent the respective flanges 200a, 202a are provided two piston and cylinder indicators 26. These operate in a known manner: the cylinder 26b is in fluid communication with the secondary carcasses 200b, 202b of the respective hose sections 200,202 such that any leakage from the primary carcasses 200c,202c to the secondary carcasses 200b, 202b causes the pistons 26a to extend or retract. Tethers 25 form a fluid and mechanical connection between the T- Connectors 24 and the pistons 26a.

In this particular embodiment, Fig. 7 shows a normal working condition, where leakage is not occurring, and consequently two fluid lines 22a, 22b and T-Connectors 24 form continuous and unbroken fluid paths.

As shown in Fig. 7, the first fluid line 22a connects to the piston and cylinder indicator 26 of the first or left hand double carcass hose section 200, whereas the second fluid line 22b connects to the second or right hand double carcass hose section 202. In this embodiment all along the hose line 204, the first fluid line 22a connects to the piston and cylinder indicators 26 at the right hand end of a hose section to the left of a corresponding flange (from the perspective of the Figs) whereas the second fluid line 22b connects to the piston and cylinder indicators 26 at the left hand end of a hose section to the right of a corresponding flange.

Actuation of the system is much like that described for the first

embodiment above.

The two fluid lines 22a,22b may be completely separate and may be pressurised and monitored separately, or they may form a loop running from the combined pump and pressure gauge 28, along first fluid line 22a, onto second fluid line 22b and back to the combined pump and pressure gauge 28.

This arrangement of two fluid lines provides the second embodiment with a degree of redundancy, as the fluid lines connect in a "parallel" arrangement, as opposed to a "series" arrangement. Moreover, two separate lines may allow for more precise location of a leakage by the respective pressure changes monitored by the combined pump and pressure gauge 28. For example, if a T-Connector 24 is removed from the first fluid line 22a near the combined pump and pressure gauge 28, the relative quicker drop in pressure of first fluid line 22a as opposed to second fluid line 22b could indicate to the operator that the leakage was occurring at a certain point. If a T-Connector 24 was removed from the first fluid line 22a at approximately the mid-point of the system, the relative pressure drops of first fluid line 22a and second fluid line 22b would display a greater degree of similarity, and hence could indicate to an operator that leakage was occurring at a different point than the first example.

A third embodiment of the present invention is shown in Figs. 9 to 1 1 .

A leakage detector 30 comprises a threaded connector 32, mounted upon a housing 34. It is composed substantially of a stainless steel. As can be seen best from Fig. 9, the housing has a substantially hexagonal cross section.

Within a portion of an outer wall 36 of the housing 34 is provided viewing apertures 38. Housed within the housing 34 is a bulb 40, which is composed from a suitable clear plastics material. Within the bulb 40, a piston 42 and cylinder 44 arrangement 46 is provided. A central bore 48 runs through the threaded connector 32 and is in fluid communication with the piston 42 and cylinder 44 arrangement 46. In use, the leakage detector 30 can be attached to a hose section (not shown) via a threaded boss (not shown) located behind a flange (not shown) of the hose section. In this arrangement, the bore 48 will therefore provide fluid communication between the secondary carcass (not shown) and the piston 42 and cylinder 44 arrangement 46. Consequently, should there be leakage from the primary carcass (not shown) to the secondary carcass, the leaked fluid will enter the cylinder 44 and extend the piston 42 into a more prominent position. Fig. 10 shows this situation, whilst Fig. 1 1 shows a normal working arrangement where no leakage is occurring and hence the piston 42 remains largely concealed.

This arrangement provides a degree of shielding for the piston 42 from environmental factors which may inhibit proper functioning, such as contaminants, external fluid pressure, etc.

Modifications and improvements can be made to the embodiments herein before described without departing from the scope of the invention.

For example, although the indicator substance is described as a fluid, it may be a powder or other suitable form for the invention.

Moreover, although described as the monitoring of a pressurised fluid, the invention may equally involve the selective breaking of an electrical circuit, fibre-optic transmission, or other suitable system.

Although described as being luminous, the detection substance may be simply a highly visible shade of appearance, and may not necessarily exhibit luminous qualities.

Claims

1 . A leak detection system comprising a signal line connected to a gauge, and at least one signal line control device, the signal line control device being actuated by a leakage within a system being monitored.

2. A leak detection system according to Claim 1 wherein the signal line is a fluid line, with the signal line control device being a fluid line control device and the gauge being a pressure gauge.

3. A leak detection system according to Claim 2 wherein the pressure gauge is mechanical or electronic, and is further connected to control systems to shut down or otherwise control the system which the leak detection system is monitoring.

4. A leak detection system according to Claims 2 or 3 wherein the fluid line control device is configured to cause leakage within the fluid line such that a detection fluid within said fluid line leaks from the system.

5. A leak detection system according to Claim 4 wherein the fluid line employs a detection fluid with an enhanced visual appearance.

6. A leak detection system according to Claims 4 or 5 wherein the fluid line employs a luminescent detection fluid.

7. A leak detection system according to any of Claims 2 to 6 wherein the fluid line control device comprises a cylinder and piston arrangement, the cylinder and piston arrangement being actuated by a leakage within a system being monitored.

8. A leak detection system according to Claim 7 wherein the fluid line has a section that passes through said cylinder and piston arrangement.

9. A leak detection system according to Claims 7 or 8 wherein the cylinder and piston are mechanically connected to a valve upon the fluid line.

10. A leak detection system according to any of Claims 2 to 9 including two or more fluid lines as signal lines.

1 1 . A leak detection system according to any of Claim 2 to 10 wherein the fluid line or fluid lines are helically wound around a system being monitored.

12. A leak detection system comprising a detection substance reservoir, and a detection substance control device being actuated by a leakage within a system being monitored.

13. A leak detection system according to Claim 12 wherein the detection substance has an enhanced visual appearance.

14. A leak detection system according to Claims 12 or 13 wherein the detection substance is a luminescent detection fluid.

15. A leak detection system according to any of Claims 12 to 14 wherein the detection substance reservoir is in the form of a fluid line, and the fluid line is pressurised.

16. A leak detection system according to any of Claims 12 to 15 further comprising a pressure gauge or gauges employed to monitor pressure within the detection substance reservoir.

17. A leak detection system according to any of Claims 12 to 16 wherein the detection substance control device comprises a cylinder and piston arrangement, the cylinder and piston arrangement being actuated by a leakage within a system being monitored.

18. A leak detection system according to Claim 17 including a fluid line that connects to the detection substance reservoir and has a section that passes through said cylinder and piston arrangement.

19. A leak detection system according to any of Claims 12 to 18 comprising two or more detection substance reservoirs.

20. A leak detection system comprising a piston and cylinder arrangement, and a casing around part of said piston and cylinder arrangement, said casing having a clear portion.

21 . A leak detection system according to Claim 21 wherein the casing encloses an extending portion of said piston and cylinder arrangement.

22. A leak detection system comprising at least two leak detection systems according to any preceding claim.

23. A fluid system including at least one leak detection system according any preceding claim.

24. An oilfield including at least one leak detection system according to any of Claims 1 to 22 or a fluid system according Claim 23.

25. A method of detecting a leak comprising the steps of linking a detection substance supply to a primary fluid supply, such that leakage of the primary fluid supply affects a physical characteristic of the detection substance supply, and monitoring said physical characteristic of said detection substance supply.

26. A method of detecting a leak according to Claim 25 wherein the physical characteristic is the pressure of the detection substance supply.

27. A method of detecting a leak according to Claims 25 or 26 wherein the detection substance supply is linked to the primary fluid supply by a cylinder and piston arrangement.

28. A method of detecting a leak according to any of Claims 25 to 27 wherein a detection substance within the detection substance supply has an enhanced visual appearance.

29. A method of detecting a leak according to any of Claims 25 to 28 further including transporting the detection substance to an area that may be visually monitored by a user.

30. A method of detecting a leak comprising the steps of linking a detection substance supply to a primary fluid supply, such that leakage of the primary fluid supply causes leakage of the detection substance supply, and monitoring said detection substance leakage.

31 . A method of detecting a leak according to Claim 30 wherein a detection substance within the detection substance supply has an enhanced visual appearance.

32. A method of detecting a leak according to Claims 30 or 31 wherein a detection substance within the detection substance supply is

luminescent.