WO2010112899A1

WO2010112899A1 - Gas cylinder filling system

Info

Publication number: WO2010112899A1
Application number: PCT/GB2010/050508
Authority: WO
Inventors: Robert Lee; Graham Smith; George Kynoch Yule; Stewart Sim; Eric Watson
Original assignee: Dominion Technology Gases Limited
Priority date: 2009-04-01
Filing date: 2010-03-25
Publication date: 2010-10-07
Also published as: GB2469084B; GB2469084A; GB0905610D0

Abstract

A gas supply module including a container having at least one detachable side and within which is housed a gas conversion system. The detachable side provides a means for converting the gas supply module between a transportation mode and an operational mode. The gas conversion system is configured to convert a liquid gas contained within a tank to a pressurised gas supply.

Description

Gas Cylinder Filling System

The present invention relates to the field of gas cylinders and in particular to filling systems for gas cylinders.

Pure gases and gas mixtures are employed within a range of technical fields and for a wide variety of purposes. For example, gas mixtures are frequently employed for welding and cutting; helium/nitrogen and helium/oxygen gas mixtures are employed as breathing gases for underwater divers; while pure argon, helium, hydrogen, nitrogen, oxygen gases and mixtures thereof are employed for a wide variety of scientific and analytical purposes, to name but a few. In practice, the number of permutations and combinations of the various gases are restricted only by the physical and chemical properties of the components and by health and safety issues relevant to their production, as well as the stability and quality of the final mixture.

Cylinders are presently employed to facilitate the transportation of these gases. Typically these cylinders are employed individually or within cylinder bundles e.g. as 16, 48 or 64 cylinder quads. Their construction materials include aluminium, steel, light alloys, and composite materials, as well as special porous interior materials for acetylene. When a gas is required at a particular location an order is typically placed by a customer with a gas supplier. The required pure gas or gas mixture is then prepared and bottled under high pressure within gas cylinders by the gas supplier, typically at their nearest plant to the required location for the gas. Thereafter, the gas supplier is required to transport the gas cylinders from their plant to the desired location.

As will be appreciated by those skilled in the art, the transportation process often involves the movement of large quantities of high pressure gas cylinders over great distances. The transportation process is therefore a significant, time consuming inconvenience to the gas supplier that not only increases the costs involved but is also potentially hazardous, depending on the chemical content of the pure gases and/or the gas mixtures being transported.

If a customer requires a large quantity of gas over a significant period of time for a particular project it is known for a gas supplier to build a bespoke gas plant at the desired location. However, this is an expensive solution requiring a significant level of man power to carry out the in situ welding and testing of the required plant and associated pipe work. As a result, such a solution is not always available and if carried out can result in an abandoned gas plant being left when the particular project has been completed.

It is therefore an object of an aspect of the present invention to provide a gas cylinder filling system that obviates or at least mitigates the disadvantages of gas filling systems described in the prior art.

Summary of Invention

According to a first aspect of the present invention there is provided a gas supply module, the gas supply module comprising a container having at least one detachable side and within which is housed a gas conversion system, wherein removal of the detachable side converts the gas supply module between a transportation mode and an operational mode whereby the gas conversion system is configured to convert a liquid gas contained within a tank to a pressurised gas supply. Housing the gas conversion system within the container allows it to be physically protected during periods of transportation. However, when the at least one detachable side is removed the gas conversion system is provided with a suitable environment to allow it to operate.

Optionally the gas conversion system comprises a vaporiser at least one section of which is located along the detachable side of the container. Most preferably the vaporiser comprises an ambient air vaporiser. Removal of the at least one detachable side therefore provides the ambient air vaporiser with a sufficient air supply in order to allow it to operate.

Optionally the container comprises three detachable sides and the ambient air vaporiser system comprises a section located along each of the three detachable sides. Increasing the number of detachable sides and associated sections of the vaporiser system increases the efficiency of the conversion process.

Preferably the sides are detachable from a container frame.

It is also preferable for a fourth side of the container to be pivotally mounted to the container frame so as to provide an access point to the container. Alternatively, the container comprises a fourth side that is detachable from the container frame.

It is preferable for the tank to be located on top of the container. Such an arrangement provides the contained liquid with a sufficient pressure head for the conversion process.

Optionally the gas conversion system further comprises a pump located between the tank and the vaporiser. The inclusion of the pump provides a means for controlling the pressure of the gas supply. Such embodiments are suitable for the provision of oxygen, nitrogen, carbon dioxide and argon gases.

The gas supply module may further comprise a cut out valve in a suction line and a return line between the pump and the tank. Preferably a driving gas is employed to remotely open and close the cut out valves. This is a safety feature intended to be deployed in the event of a fire where it is important that a liquid oxygen supply can be quickly isolated from the seat of the fire. Alternatively the gas supply system comprises a heat exchanger. Preferably the gas supply system further comprises a compressor the compressor package being located so as to position the heat exchanger between the compressor and the tank. The inclusion of the compressor package provides a means for controlling the pressure of the gas supply. Such embodiments are suitable for the provision of helium gas.

Optionally the container comprises five removable sides.

The container may comprise a module control unit. Optionally the module control unit is located on an external surface of the container. The module control unit preferably comprises a pump start button, a pump stop button and a module emergency stop button. The combination of these features provides a means for manual operation of the pump.

It is preferable for the gas supply module to further comprise a gas monitor that provides a means of detecting a gas leak. Preferably the gas monitor is an oxygen gas monitor.

Optionally, the module control unit may also comprise a gas monitor alarm that is activated when a gas leak is detected by the gas monitor.

The module control unit may also comprise a time indicator that provides a means of indicating the time the pump has been in operation.

Optionally the container is fitted with an alarm which is activated when a body enters the container.

Preferably the gas supply module further comprises a power generator housed with the container, the power generator providing a dedicated power source for the module. Alternatively, or in addition, the gas supply module further comprises an electrical control panel suitable for receiving an external power source for the module.

According to a second aspect of the present invention there is provided a system control module for a gas cylinder filling system wherein the system control module comprises a container within which is housed a fill and analysis unit. Preferably the system control module further comprises a tank. It is preferable for the tank to be located on top of the container. Such an arrangement provides the contained liquid with a sufficient pressure head for the bottling process.

Optionally the system control module further comprises an office space housed within the container. The office space provides an operator with an area to safely operate the gas cylinder filling system.

The fill and analysis unit preferably comprises one or more mixture filling modules. The fill and analysis unit may further comprise an analysis module. Preferably the fill and analysis unit also comprises a vacuum system.

Preferably the one or more mixture filling modules comprise one or more filling valves suitable for providing fluid communication with a gas supply module.

The one or more mixture filling modules may also comprise a supply gas swing hose adapted to selectively connect the one or more filling valves to a cylinder filling system.

Optionally the cylinder filling system comprises a quad filling hose. Alternatively the cylinder filling system comprises a multiple point cylinder filling manifold.

Optionally the one or more mixture filling modules comprise a temperature gauge that provides a means for measuring the temperature of any cylinder deployed with the filling modules.

The analysis module preferably comprises a test cylinder connection point that provides a means for connecting a cylinder to one or more cylinder diagnostics selected from a set of cylinder diagnostics comprising a pressure gauge, a moisture analyser, an oxygen gas analyser, a carbon dioxide gas analyser, and a gas chromatograph.

The analysis module may comprise and an instrument calibration apparatus. It is preferable for the analysis module to further comprise a nitrogen purge facility.

Preferably the system control module further comprises a power generator housed with the container, the power generator providing a dedicated power source for the module. Alternatively, or in addition, the system control module further comprises an electrical control panel suitable for receiving an external power source for the module. The electrical control panel may provide a means for distributing power to a gas supply module.

According to a third aspect of the present invention there is provided a gas cylinder filling system comprising one or more gas supply modules in accordance with the first aspect of the present invention.

A gas cylinder filling system made up of individual modules based on a container provides a system that is both highly mobile and flexible in its deployment. By employing different modules within different systems provides a customer with a bespoke gas cylinder filling system. The container based system also allows the gas cylinder filling system to be easily disassembled and thus removed at the end of a project.

Preferably the one or more gas supply modules supply one or more gases selected from a group of gases comprising oxygen, nitrogen, carbon dioxide, argon and helium.

Most preferably the gas cylinder filling system further comprises a system control module in accordance with the second aspect of the present invention. In this way the mixture filling modules provide a means for mixing the gases provided by the one or more gas supply modules to a customer required specification.

Optionally the gas cylinder filling system further comprises a power source connected to the electrical control panel of the system control module. The electrical control panel may be configured to distribute power to the one or more gas supply modules.

According to a fourth aspect of the present invention there is provided a method of deploying a gas cylinder filling system the method comprising the steps of: -selecting one or more one or more gas supply modules in accordance with the first aspect of the present invention; -transporting the one or more gas supply modules to a required location for the gas cylinder filling system -connecting the one or more gas supply modules together at the required location. Preferably the method of deploying a gas cylinder filling system further comprises the steps of -selecting a system control module in accordance with the second aspect of the present invention; -transporting the system control module to the required location; and -connecting the system control module to the one or more gas supply modules.

According to a fifth aspect of the present invention there is provided a gas supply module, the gas supply module comprising a container having at least one detachable side and within which is housed a vaporiser system, at least one section of which is located along the detachable side of the container, wherein the detachable side provides a means for converting the gas supply module between a transportation mode and an operational mode within which the vaporiser system is configured to convert a liquid gas contained within a tank to a pressurised gas supply.

Embodiments of the fifth aspect of the invention may comprise the preferred or optional features of the first aspect of the invention or vice versa.

According to a sixth aspect of the present invention there is provided a gas supply module, the gas supply module comprising a container having at least one detachable side and within which is housed a heat exchanger wherein the detachable side provides a means for converting the gas supply module between a transportation mode and an operational mode within which the heat exchanger system is configured to convert a liquid gas contained within a tank to a pressurised gas supply.

Embodiments of the sixth aspect of the invention may comprise the preferred or optional features of the first aspect of the invention or vice versa.

Brief Description of Drawings

Aspects and advantages of the present invention will become apparent upon reading the following detailed description of example embodiments and upon reference to the following drawings in which: Figure 1 presents a schematic representation of a mobile gas filling system in accordance with an embodiment of the present invention;

Figure 2 presents further detail of an oxygen gas supply module and a nitrogen gas supply module of the mobile gas filling system of Figure 1 ;

Figure 3 presents a process and instrumentation diagram of the oxygen gas supply module incorporated within the mobile gas filling system of Figure 1 ;

Figure 4 presents a process and instrumentation diagram of a supply line between the oxygen gas supply module and the system control module;

Figure 5 presents a process and instrumentation diagram of the nitrogen gas supply module incorporated within the mobile gas filling system of Figure 1 ;

Figure 6 presents a process and instrumentation diagram of a supply line between the nitrogen gas supply module and a system control module;

Figure 7 presents further detail of a helium compressor module and the system control module of the mobile gas filling system of Figure 1 ;

Figure 8 presents a process and instrumentation diagram of the helium compressor module incorporated within the mobile gas filling system of Figure 1 ;

Figure 9 presents a process and instrumentation diagram of a mixture filling module of the system control module;

Figure 10 presents a process and instrumentation diagram of an analysis module of the system control module; and

Figure 1 1 presents a process and instrumentation diagram of a vacuum system housed within the system control module.

In the description which follows, like parts are marked throughout the specification and drawings with the same reference numerals. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of embodiments of the invention.

Detailed Description

In order to provide understanding of the various aspects of the present invention an exemplary gas cylinder filling system 1 designed to fill various gas mixtures will now be described with reference to Figure 1.

From Figure 1 , the gas cylinder filling system 1 can be seen to comprise three gas supply modules, namely an oxygen gas supply module 2, a nitrogen gas supply module 3, and an argon gas supply module 4. The gas cylinder filling system 1 further comprises a helium compressor module 5 for use with a cryogenic helium tanker (not shown) and a system control module 6.

Each of the modules 2, 3, 4, 5 and 6 of the mobile gas filling system 1 are based on a standard twenty foot container 7 that is suitable and certified for international transport and stacking and so provide a relatively simple and secure means for transporting each of these modules 2, 3, 4, 5 and 6. Although it is preferable to employ this standard sized container it will be appreciated that the invention is not restricted to the use of such containers. Significantly, however, is the fact that the sides of the containers 7 have been adapted so as to allow them to be removed, or retracted, from a structural frame 8 of the container 7, as described in further detail below.

Oxygen Gas Supply Module

Further detail of the oxygen gas supply module 2 is now provided with reference to the schematic representation of Figure 2 and the process and instrumentation diagrams of Figure 3 and Figure 4. In particular, Figure 3 presents a process and instrumentation diagram of the oxygen gas supply module 2 while Figure 4 presents a process and instrumentation diagram of a supply line between the oxygen gas supply module 2 and the system control module 6.

The oxygen gas supply module 2 comprises a twenty foot, ISO tank 9 containing liquid oxygen and a module control unit 10 both of which are mounted on top of the container 7. A Wessington ISO-Vac 5500 horizontal cryogenic vacuumed ISO tank is a suitable vessel to be employed as the oxygen gas ISO tank 9. These ISO tanks have a capacity of 20,566 litres, an empty weight of 9000kg and a maximum gross weight of 36,000kg. They are specifically designed to transport liquid gas by road, rail and sea, and satisfy the ADR, RID, IMDG, CSC and DOT regulations relating to the carriage of dangerous goods. They are self-pressuring tanks, which employ the pressure of the contained liquid to allow this liquid to be decanted at high flow rates without the need for the employment of an external pump.

Housed within the container 7 is a power generator 11 (a 100 KVA unit being one such suitable power generator) is employed to provide a 400V AC 3ph 50Hz power supply to drive a single speed pump 12 (a Krytem TLC36.6/420 22kW being one such suitable pump). A bespoke ambient air vaporiser 13 is also housed within the container 7, further details of which are provided below. Cryogenically insulated hoses provide the required suction 14 and return 15 lines between the pump 12 and the liquid oxygen ISO tank 9. Both the suction 14 and return 15 lines are equipped with automatic cut out valves 16a and 16b, thermal relief valves 17a and 17b and a purge valve 18.

A nitrogen supply 19 is provided as a driving gas to remotely open and close the two emergency shut-off valves 16a and 16b. This is a safety feature intended to be deployed in the event of a fire where it is important that the liquid oxygen supply can be quickly isolated from the seat of the fire i.e. the pump 12 or the power generator 1 1.

The pump 12 also incorporates a number of components to protect it from various situations, namely: 1 ) a high discharge pressure switch 20 is employed to stop the pump 12 in the event of a high discharge pressure. This trip is designed to prevent over pressurisation of all of the pipe work system (including the pump) without lifting the primary safety device, namely pressure relief valve 21 whose activation results in the venting of high pressure gas; 2) a low temperature switch 22 is employed to stop the pump 12 when the temperature exit of the vaporiser drops below -20⁰C. This trip is designed to prevent low temperatures damaging pipes, valves, fittings and cylinders not designed to withstand such low temperatures. The trip is also an indication that the vaporiser 13 has become overloaded and needs de-frosting; 3) a high temperature switch 23 is employed to stop the pump 12 and a trim heater (if fitted) when the temperature exit of the vaporiser rises above 60⁰C. This trip is designed to prevent high temperatures damaging pipes, valves, fittings and cylinders not designed to withstand such high temperatures. The trip is also an indication that the trim heater (if fitted) is not working correctly; 4) high temperature switches 24 and 25 are employed to stop the pump 12 when the temperature on the pump return 15 and suction lines 14, respectively, is high. These trips are designed to prevent the pump 12 running dry (no liquid) and causing wear to parts designed to run at low temperatures; 5) a low temperature switch 26 is employed to stop the pump 12 when the temperature at a stuffing box is low. This trip is designed to prevent cold damage to the pump warm end parts; and 6) A motor overload switch 27 activates when the pump 12 is overloaded.

The module control unit 10 comprises a pump start button 28, a pump stop button 29 and a module emergency stop button 30 the combination of which provide a means for manual operation of the pump 12. In this mode the pump 12 is started via the pump start button 28 and will continue to run until either the pump stop button 29 is pressed or until the high pressure switch 20 trip switch point is achieved.

The module control unit 10 may also provide an indication of the time the pump 12 has been in operation, an indication of the functionality of an oxygen monitor (high/Low) and a visual or audible entry alarm warning activated by a monitor located within the container 7. As each of the above described trip situations requires a manual reset by an operator before the pump 12 can restart the module control unit 10 may be also employed to provide an indication to this effect.

Further optional features (not shown) that may be incorporated into the module control unit 10 include a mains power switch, a tank valves open button, a tank valves closed button, a control supply on lamp, an interlocks OK lamp, a tank valves open lamp, a pump running lamp, a pump heater on lamp, a motor fault lamp, a pump suction high temperature lamp, a pump discharge high temperature lamp, a vaporiser outlet low temperature lamp, a seal packing low temperature lamp, a vaporiser outlet high pressure lamp, a pump suction temperature indicator, a pump discharge temperature indicator, a vaporiser exit temperature indicator and a pump seal temperature indicator. As well as the above described manual operation of the module control unit 10, this unit may also be remotely controlled from the system control module 6, as described in further detail below.

In the supply line between the vaporiser 13 and the system control module 6 are located the following safety features for the oxygen gas supply module 2, namely a pressure contact gauge 31 employed as a line pressure indicator and a controlled pump stop, over pressure protection valves (to external) 32, line vent valves 33, and a supply line isolation valve 34.

The above arrangement allows the oxygen pump system to be fully isolated and depressurised at any time.

An important operational design feature of the oxygen gas supply module 2 is the fact that the oxygen ISO tank 9 is located on top of the container 7. This arrangement provides the pump 12 with a sufficient head of pressure to operate such that the oxygen gas supply module 2 is capable of providing and maintain an oxygen gas supply at a suitable line pressure to the system control module 6, as presented schematically within the process and instrumentation diagram of Figure 4. The design pressure of the presently described oxygen supply system is 420 BarG.

Important to the efficiency of the oxygen gas supply to the system control module 6 is the arrangement of the ambient air vaporiser 13 within the container 7. As can be seen from Figures 1 and 2, the ambient air vaporiser 13 is built into three sides of the container 7 and is the primary means of vaporising the oxygen liquid gas as it exits the pump 12. The vaporiser 13 comprises multiple arrays of finned tubes arranged to provide conversion rates of up to 8 litres per minute at air operating temperatures between -10⁰C and 50⁰C, with the greatest efficiently being provided at an ambient air temperature of 15°C. When deployed for use the three corresponding sides of the container 7 are removed from the frame thus exposing a large surface area of the ambient air vaporiser 13 to the surrounding air. This allows the ambient air vaporiser 13 to operate in an efficient manner and so avoids the normal requirement to provide a separate, stand alone vaporiser unit. A stand alone vaporiser would need to be piped up and separately mounted from the oxygen gas supply module 2 and so the removal of this requirement greatly increases the mobility of the module 2.

The side 35 of the container not comprising a section of the ambient air vaporiser 13 is arranged to be retractable. As a result, the retractable side 35 provides an easy access point for an operator to the inside of the container 7. Thus, by isolating and depressurising the pump system the operator can then access the inside of the container 7 via the retractable side 35 so as to carry out any required maintenance.

Nitrogen Gas Supply Module

Details of the nitrogen gas supply module 3 are provided within the schematic representation of Figure 2 and the process and instrumentation diagrams of Figure 5 and 6. In particular, Figure 5 presents a process and instrumentation diagram of the nitrogen gas supply module 3 while Figure 6 presents a process and instrumentation diagram of the supply line between the nitrogen gas supply module 3 and the system control module 6.

As can be seen the nitrogen gas supply module 3 comprises many components in common with the previously described oxygen gas supply module 2, namely a twenty foot, liquid ISO tank 9, now containing liquid nitrogen, and a module control unit 10 both of which are again mounted on top of the container 7. A Wessington ISO-Vac 5500 horizontal cryogenic vacuumed ISO tank is again a suitable vessel to be employed as the nitrogen gas ISO tanks 9.

Housed within the container 7 is again a power generator 1 1 (a 100 KVA unit being one such suitable power generator) employed to provide a 400V AC 3ph 50Hz power supply to drive a pump 12. An ambient air vaporiser 13 is also housed within the container 7. Cryogenically insulated hoses again provide the required suction 14 and return 15 lines between the pump 12 and the liquid nitrogen ISO tank 9. Both the suction 14 and return 15 lines are equipped with thermal relief valves 17a and 17b and a purge valve 18.

The pump 12 also incorporates the above described safety components, namely: 1 ) a high discharge pressure switch 20 employed to stop the pump 12 in the event of a high discharge pressure; 2) a low temperature switch 22 employed to stop the pump 12 when the temperature exit of the vaporiser drops below -20⁰C; 3) a high temperature switch 23 employed to stop the pump 12 and a trim heater (if fitted) when the temperature exit of the vaporiser rises above 60⁰C; 4) high temperature switches 24 and 25 employed to stop the pump 12 when the temperature on the pump discharge and suction, respectively, is high; 5) a low temperature switch 26 employed to stop the pump 12 when the temperature at a stuffing box is low, typically set to activate at-120C; and 6) a motor overload switch 27 that activates when the pump 12 is overloaded.

The module control unit comprises a pump start button 28, a pump stop button 29 and a module emergency stop button 30 that again provide a means for manual operation of the pump 12. In this mode the pump 12 is started via the pump start button 28 and will continue to run until either the pump stop button 29 is pressed or until the high pressure switch 20 trip switch point is achieved.

The module control unit 10 may also provide an indication of the time the pump 12 has been in operation, an indication of the functionality of an oxygen and a nitrogen monitor (high/Low) and a visual or audible entry alarm warning activated by a monitor located within the container 7. As each of the above described trip situations requires a manual reset by an operator before the pump 12 can restart the module control unit 10 may also be employed to provide an indication to this effect.

Further optional features (not shown) that may be incorporated into the module control unit 10 include a mains power switch, a tank valves open button, a tank valves closed button, a control supply on lamp, an interlocks OK lamp, a tank valves open lamp, a pump running lamp, a pump heater on lamp, a motor fault lamp, a pump suction high temperature lamp, a pump discharge high temperature lamp, a vaporiser outlet low temperature lamp, a seal packing low temperature lamp, a vaporiser outlet high pressure lamp, a pump suction temperature indicator, a pump discharge temperature indicator, a vaporiser exit temperature indicator and a pump seal temperature indicator.

As well as the above described manual operation of the module control unit 10, this unit may also be remotely controlled from the system control module 6, as described in further detail below. In the supply line between the vaporiser 13 and the system control module 6 are located the following safety features for the nitrogen gas supply module 3, namely a pressure contact gauge 31 employed as a line pressure indicator and a controlled pump stop, over pressure protection valves (to external) 32 , line vent valves 33, and a supply line isolation valve 34.

The above arrangement allows the nitrogen pump system to be fully isolated and depressurised at any time.

The operation of the nitrogen gas supply module 3 is similar to that previously described with respect to the oxygen gas supply module 2. The nitrogen ISO tank 9 on top of the container 7 provides the pump 12 with a sufficient head of pressure to operate such that a nitrogen gas supply can be provided to the system control module 6, as presented schematically within the process and instrumentation diagram of Figure 6. The design pressure of the presently described nitrogen supply system is again 420 BarG.

Important to the efficiency of the nitrogen gas supply to the system control module 6 is the arrangement of the ambient air vaporiser 13 within the container 7 which is again built into three sides of the container 7. The remaining side 35 of the container 7 is retractable so as to provide access to the components of the module 3 housed within the container 7.

A point to note about the process and instrumentation diagram of Figure 6 is the presence of a dedicated nitrogen filling point 36. The dedicated nitrogen filling point 36 is provided because nitrogen in an unmixed state is a gas frequently required by customers. Therefore, it is useful to have a source for bottling nitrogen gas that is independent of the system control module 6.

A further point to note is that, unlike the oxygen gas supply module 2, emergency valves with a dedicated nitrogen supply are not required within this module 3 since there is no need to isolate nitrogen from any fire within the module 3. Argon Gas Supply Module

The third gas supply module 4 is employed to provide a source of argon gas to the system control module 6. To all intensive purposes this module 4 is identical to that of the previously described nitrogen gas supply module 3 except for the fact that the liquid contained within the ISO tank 9 is argon, and there is no requirement for a dedicated gas filling point 36.

In an alternative embodiment, the third gas supply module 4 is employed to provide a source of carbon dioxide gas to the system control module 6.

Helium Compressor Module

Details of the helium compressor module 5 will now be described with reference to Figures 7 and 8. In particular, Figure 7 presents a schematic representation of the helium compressor module 5 while Figure 8 presents a process and instrumentation diagram of the helium compressor module 5.

As can be seen the structure of the helium compressor module 5 differs significantly from the previously describe gas modules. The main reason for this is the chemical composition of helium which results in it being significantly colder (at the same volume and pressure) than any of oxygen, nitrogen, argon or carbon dioxide when provided as a cryogenically cooled liquid.

The module 5 is however again based on a container 7 this time comprising five removable sides. However, unlike the previously described modules the helium compressor module 5 does not comprise an ISO tank 9 located on top of the container 7. Instead a helium tanker (not shown) is required to be connected to a compressor package 37 that is located within the helium compressor module 5. The compressor package 37 is designed to convert the helium liquid within the tanker to a maximum of 320 bar gauge of helium gas at 176 m³/hr to the system control module 6.

In order to achieve this result, and with reference to Figure 8, the compressor package 37 comprises an internal coil heat exchanger 38, that employs a heating element 39 to heat the helium liquid so as to convert it to a gaseous state, and a compressor 40 which provides a means for controlling the pressure output of the helium gas. The required power for these components is provided by a power supply 41 . To assist in this conversion process the compressor package 37 further comprises a helium gas receiver 42 located between the heat exchanger 38 and the compressor 40.

In the presently described embodiment the heat exchanger 38 is a Krytem water bath heat exchanger with a recirculation pump and is capable of converting 200 liquid Nm³ per hour, the compressor 40 is a CompAir (RTM) H5437.1.He helium compressor while the power supply 41 is a 75 kw rating (absorbed 55 kw) Star delta with fixed soft start, 40Ov 3 phase supply that is capable of operating at either 50 or 60 hertz and is water cooled (closed system) a with trim cooler 43 based on a maximum ambient temperature of 55°C.

The compressor 40 may comprise the following features (not explicitly shown), namely: a let-down package, a low pressure trip, a high pressure trip, a low temperature inlet trip, a filtration package, a high pressure relief valve set at 10% above maximum working pressure of the module 6, and a 0-400 BarG pressure contact gauge adapted to trip the compressor package 37 during a period of rising pressure.

A compressor control unit (not shown) is also provided on the compressor package 37. This control unit comprises a compressor start button, a compressor stop button and a module emergency stop button that provide a means for manual operation of the compressor package 37. In this mode the compressor package 37 is started via the compressor start button and will continue to run until either the compressor stop button is pressed or until the high pressure switch trip switch point is achieved.

The compressor control unit may also provide an indication of the time compressor package 37 has been in operation. Further optional features that may be incorporated into the compressor control unit include a mains power switch, a control supply on lamp, an interlocks OK lamp, a compressor running lamp, a compressor cooler on lamp, a motor fault lamp, a compressor suction high pressure lamp, a compressor suction low pressure lamp, a compressor discharge high pressure lamp and a compressor discharge high temperature lamp. As well as the above described manual operation of the compressor package 37, this unit may also be remotely controlled from the system control module 6, as described in further detail below.

From Figure 8, the supply line of the helium compressor module 5 can be seen to comprise a check and fill valve line 44, a c/w vent 45 (to external), a pressure gauge 46, a quad fill hose with parking position (to external) 47 that allows for the filling of a manifold cylinder package with helium gas, a pressure relief valve 48 for lower pressure helium gas fills, an on line cylinder buffer 49 to allow for minor component decanting, and supply line isolation valves 50.

When the module 5 is to be deployed in an operational mode it is advantageous for all of the removable sides of the container 7 to be removed. In the first instance this is required to assist in the process of connecting the helium tanker (not shown) to the heat exchanger 38. If the remaining sides of the container 7 are not also removed then the compressor package 37 would effectively be housed within an open sided cavity which would act to amplify the noise produced during the operation of the compressor package 37. Removal of the remaining sides of the container 7 thus reduces this amplifying effect and so improves the operating safety of the helium compressor module 5. This effect can be further reduced by mounting the compressor package 37 on anti-vibration mounts 51 .

System Control Module The final module that makes up the mobile gas filling system 1 is the system control module 6 details of which can be seen in Figure 7. The system control module 6 comprises three distinct components, namely an office space 52 and a fill and analysis unit 53, both located within the container 7, and a ten foot, ISO tank 54 located on top of the container 7. Also housed within the container 7 is a power generator 1 1 (a 100 KVA unit being one such suitable power generator) that is employed to provide a 400V AC 3ph 50Hz power supply for the system control module 6.

The office space 52 takes up approximately one half of the volume of the container 7 and provides an operator with a safe working space within the mobile gas filling system 1. This office space 52 may be equipped with an air conditioning unit. The second half of the container 7 is employed to house the fill and analysis unit 53 which comprises a mixture filling module 55, an analysis module 56 and a vacuum system 57 for the mobile gas filling system 1 . Further details of each of these components are provided below.

The ISO tank 54 on top of the container 7 contains carbon dioxide in a liquid state. It therefore provides a pressurised source of carbon dioxide gas for the mixture filling module 55 as described in further detail below.

With reference to the process and instrumentation diagram of Figure 9 the mixture filling module 55 provides a means for filling one, or multiple gas cylinders with various gases or gas mixtures. It can be seen in fact to comprise two separate filling modules, 55a and 55b, both of which are shown connected to oxygen 58, nitrogen 59 and helium supply lines 60. Each filling module, 55a and 55b, comprises five check and fill valves, one for each of the oxygen gas supply 61 a and 61 b, the nitrogen gas supply 62a and 62b the helium gas supply 63a and 63b the argon gas supply 64a and 64b and the carbon dioxide gas supply 65a and 65b. Each check and fill valve 61 a, 62a, 63a, 64a, 65a and 61 b, 62b, 63b, 64b, 65b has an associated pressure gauge 46 that provides a means for monitoring the gas pressure at the check and fill valves 61 a, 62a, 63a, 64a, 65a and 61 b, 62b, 63b, 64b, 65b.

The filling modules 55a and 55b also comprise a supply gas swing hose 66 adapted to selectively connect the check and fill valves 61 a, 62a, 63a, 64a, 65a and 61 b, 62b, 63b, 64b, 65b, respectively, to a pair of associated off valved quad filling hoses 67a and 67b. Each pair of off valved quad filling hoses 67a and 67b has an associated pressure gauge 46 and a temperature gauge 68. Filling module 55b can also be seen to comprise a valved fifteen point cylinder filling manifold 69.

Each of the filling modules 55a and 55b further comprises a low pressure relief valve 70a and 70b that provide a means for filling a single cylinder with a 200 BarG gas. Line venting valves 33 are located within a VSL external line 71 while vacuum valves 72a and 72b provide a means of isolating the filling modules 55a and 55b from the vacuum system 57. The final component of the filling modules 55a and 55b is a cylinder wall temperature gauge 73a and 73b that takes the form of a portable hand gun. This provides a means for measuring the temperature of any cylinder deployed with the filling modules 55a and 55b.

Figure 10 presents a process and instrumentation diagram of the analysis module 56 of the system control module 6 that provides a means for analysing the gas content of a cylinder. This module 56 comprises a cylinder connection point 74, a pressure gauge 46, a vent & isolation facility 75 and regulation 76 and relief valves 77. Other components of the analysis module 56 include a moisture analyser 78 with a regulated feed and flow metered vents, an oxygen and carbon dioxide gas analyser 79 (a Systech ZR894 with a valved feed being one such suitable analyser), two calibration feeds 80, and a by-pass flow meters 81 .

In addition to the above components the analysis module 56 further comprises a regulated carrier gas feed 82 to a bench mount unit 83 via a sample hose 84 along with appropriate calibration feeds 85. A carrier gas is used to ensure a constant supply of gas through the instruments thus ensuring they remain dry. As a result the carrier gas is run at all times. The calibration feeds 80 allow a calibration gas to be employed to calibrate the instruments. Typically this process would be carried out on a daily basis. The analysis module 56 may further comprise a gas chromatograph.

A nitrogen purge facility 86 is also provided as a means for purging the analysis module 56.

A process and instrumentation diagram of the vacuum system 57 is presented in Figure 11. As previously discussed, the vacuum system 57 is housed within the container 7 of the system control module 6 and is designed to evacuate residual gas as part of a cylinder fill cycle. The vacuum system 57 comprises a vacuum pump 87 that is connected to the filling modules 55a and 55b. Manual control of the vacuum pump 87 is provided via a vacuum control panel (not shown) located within the office space 52. The vacuum pump 87 is preferably air cooled, fully oxygen compatible, and rated for continuous running. A Leybold (RTM) SOGEVAC (RTM) SV65 is a vacuum pump suitable for providing this functionality. A vacuum protection valve 88 (V71 -10) is located between the vacuum pump 87 and the filling modules 55a and 55b. The vacuum protection valve 88 is arranged to close and isolate the vacuum pump 87 in the event of high suction pressure being detected by the pressure gauge 46.

From the office space 52 an operator may remotely operate the oxygen gas supply module 2, the nitrogen gas supply module 3, the argon gas supply module 4, the helium compressor module 5 and the other components of the system control module 6 via a computer interface which communicates with the associated control units.

The computer interface also provides for an overall emergency stop system that can be employed to shut down the complete mobile gas filling system 1 . This complete shut down can be activated by an operator located within office space 52 or via module emergency stop button 30 located on the outside of each of the gas supply modules 2, 3 and 4, and the helium compressor module 5. Upon activation of the emergency stop system the pumps 12 are stopped, the compressor package 37 is stopped, the oxygen pump suction 16a and return valves 16b are closed, and notification of the emergency stop is indicated on the module control units 10 and the compressor control unit. The described emergency shutdown situation needs to be manually reset by an operator before the mobile gas filling system 1 can be restarted.

Deploying the Gas Filling System

Deployment of the gas cylinder filling 1 system is as follows. Once the location for the gas cylinder filling system 1 has been determined then the various modules 2, 3, 4, 5 and 6 are transported to the required destination. The fact that each of the modules 2, 3, 4, 5 and 6 is based on a container significantly simplifies this transportation process.

The modules 2, 3, 4, 5 and 6 are then appropriately arranged, configured into their operational mode and then connected up, as appropriate. The gas cylinder filling system 1 employs a flexible piping system to connect the various modules and so removes the need for a team of welders to be on site to install and test fixed pipe work, as is required in prior art systems. Once deployed the mixture filling modules and the analysis module allow for the controlled filling and analysis of cylinders with pure gases or gas mixtures, as and when required by a customer.

In order to replenish a oxygen, nitrogen, carbon dioxide or argon gas source all that is required is for the system 1 to be isolated, the appropriate module 2, 3, 4 or 6 to be removed and replaced with a new module comprising a full ISO tank 9. The original module 2, 3, 4, or 6 can then be transported away for refilling. To replenish the helium gas source the helium tanker connected to the helium compressor module 5 has simply to be replaced.

In the above described embodiments each of the modules 2, 3, 4, 5 and 6 comprises an independent power source. In an alternative embodiment each module 2, 3, 4, 5 and 6 may comprises an electrical control panel (not sown) that is fed from a single 40Ov 3 phase 50 hertz external power supply. In a further alternative embodiment the system control module 6 may provide a single main power entry and then handle the onward distribution of power to each of the remaining modules 2, 3, 4 and 5.

It will be appreciated that the gas sources are not restricted to the provision of oxygen, nitrogen, carbon dioxide, argon or helium gases. Any alternative pure gas or gas mixture could readily be provided within a corresponding gas supply module, as and when required by a customer.

In a further alternative embodiment the system control module 6 may comprise a twenty foot, ISO tank 9 containing liquid carbon dioxide or any other suitable liquid gas.

The described gas cylinder filling system therefore provides a system that is significantly more flexible than the prior art systems which require the transportation of large numbers of gas cylinders over large distances. Being able to mix the gases in situ means that bespoke gas mixtures are more readily available and there is a reduction in the distances over which potentially hazardous gas mixtures are required to be transported.

When compared with the fixed gas plant solutions to the above problems the presently described gas cylinder filling system can again be seen to be more flexible and significantly more mobile. The present solution therefore reduces the expense involved as significantly less man power is required to deploy the system. The mobile nature of described gas cylinder filling system also avoids an abandoned gas plant being left on the completion of a particular project. The gas cylinder filling system can simply be disconnected and transported away.

The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. The described embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilise the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Therefore, further modifications or improvements may be incorporated without departing from the scope of the invention as defined by the appended claims.

Claims

1 ) A gas supply module, the gas supply module comprising a container having at least one detachable side and within which is housed a gas conversion system, wherein removal of the detachable side converts the gas supply module between a transportation mode and an operational mode whereby the gas conversion system is configured to convert a liquid gas contained within a tank to a pressurised gas supply.

2) A gas supply module as claimed in claim 1 wherein the gas conversion system comprises a vaporiser at least one section of which is located along the detachable side of the container.

3) A gas supply module as claimed in claim 2 wherein the vaporiser comprises an ambient air vaporiser.

4) A gas supply module as claimed in either of claims 2 or 3 wherein the container comprises three detachable sides and the vaporiser system comprises a section located along each of the three detachable sides.

5) A gas supply module as claimed in any of the preceding claims wherein the at least one detachable side is detachable from a container frame.

6) A gas supply module as claimed in either of claims 4 or 5 wherein the container comprises a fourth side that is pivotally mounted to the container frame so as to provide an access point to the container.

7) A gas supply module as claimed in either of claims 4 or 5 wherein the container the container comprises a fourth side that is detachable from the container frame.

8) A gas supply module as claimed in any of the preceding claims wherein the tank is located on top of the container.

9) A gas supply module as claimed in any of claims 2 to 8 wherein the gas conversion system further comprises a pump located between the tank and the vaporiser. 10) A gas supply module as claimed in claim 9 wherein the gas supply module further comprise a cut out valve in a suction line and a return line between the pump and the tank.

1 1 ) A gas supply module as claimed in claim 10 wherein a driving gas is employed to remotely open and close the cut out valves.

12) A gas supply module as claimed in claim 1 wherein the gas supply system comprises a heat exchanger.

13) A gas supply module as claimed in claim 12 wherein the gas supply system further comprises a compressor the compressor package being located so as to position the heat exchanger between the compressor and the tank.

14) A gas supply module as claimed in either of claims 12 or 13 wherein the container comprises five removable sides.

15) A gas supply module as claimed in any of the preceding claims wherein the container comprises a module control unit.

16) A gas supply module as claimed in claim 15 wherein the module control unit is located on an external surface of the container.

17) A gas supply module as claimed in either of claims 15 or 16 wherein the module control unit comprises a pump start button, a pump stop button and a module emergency stop button.

18) A gas supply module as claimed in any of the preceding claims wherein the gas supply module further comprises a gas monitor that provides a means of detecting a gas leak.

19) A gas supply module as claimed in claim 18 wherein the gas monitor is an oxygen gas monitor.

20) A gas supply module as claimed in either of claims 18 or 19 wherein the module control unit further comprise a gas monitor alarm that is activated when a gas leak is detected by the gas monitor. 21 ) A gas supply module as claimed in any of claims 15 to 20 wherein the module control unit further comprises a time indicator that provides a means of indicating the time the pump or compressor has been in operation.

22) A gas supply module as claimed in any of the preceding claims wherein the container is fitted with an alarm which is activated when a body enters the container.

23) A gas supply module as claimed in any of the preceding claims wherein the gas supply module further comprises a power generator housed with the container, the power generator providing a dedicated power source for the module.

24) A gas supply module as claimed in any of the preceding claims wherein the gas supply module further comprises an electrical control panel suitable for receiving an external power source for the module.

25) A gas cylinder filling system comprising one or more gas supply modules as claimed in any of claims 1 to 24.

26) A gas cylinder filling system as claimed in claim 25 wherein the one or more gas supply modules supply one or more gases selected from a group of gases comprising oxygen, nitrogen, carbon dioxide, argon and helium.

27) A gas cylinder filling system as claimed in either claims 25 or 26 wherein the gas cylinder filling system further comprises a system control module wherein the system control module comprises a container within which is housed a fill and analysis unit.

28) A gas cylinder filling system as claimed in claim 27 wherein the system control module further comprises a tank.

29) A gas cylinder filling system as claimed in claim 28 wherein the tank is located on top of the container.

30) A gas cylinder filling system as claimed in any of claims 27 to 29 wherein the system control module further comprises an office space housed within the container.

31 ) A gas cylinder filling system as claimed in any of claims 27 to 30 wherein the fill and analysis unit comprises one or more mixture filling modules. 32) A gas cylinder filling system as claimed in any of claims 27 to 31 wherein the fill and analysis unit further comprises an analysis module.

33) A gas cylinder filling system as claimed in any of claims 27 to 32 wherein the fill and analysis unit also comprises a vacuum system.

34) A gas cylinder filling system as claimed in any of claims 31 to 33 wherein the one or more mixture filling modules comprise one or more filling valves suitable for providing fluid communication with a gas supply module.

35) A gas cylinder filling system as claimed in claim 34 wherein the one or more mixture filling modules further comprises a supply gas swing hose adapted to selectively connect the one or more filling valves to a cylinder filling system.

36) A gas cylinder filling system as claimed in claim 35 wherein the cylinder filling system comprises a quad filling hose.

37) A gas cylinder filling system as claimed in either of claims 35 or 36 wherein the cylinder filling system comprises a multiple point cylinder filling manifold.

38) A gas cylinder filling system as claimed in any of claims 31 to 37 wherein the one or more mixture filling modules further comprise a temperature gauge that provides a means for measuring the temperature of a cylinder deployed with the filling modules.

39) A gas cylinder filling system as claimed in any of claims 32 to 38 wherein the analysis module comprises a test cylinder connection point that provides a means for connecting a cylinder to one or more cylinder diagnostics selected from a set of cylinder diagnostics comprising a pressure gauge, a moisture analyser, an oxygen gas analyser, a carbon dioxide gas analyser, and a gas chromatograph.

40) A gas cylinder filling system as claimed in any of claims 32 to 39 wherein the analysis module comprises and an instrument calibration apparatus.

41 ) A gas cylinder filling system as claimed in any of claims 32 to 40 wherein the analysis module comprises a nitrogen purge facility.

42) A gas cylinder filling system as claimed in any of claims 27 to 41 wherein the system control module further comprises a power generator housed with the container, the power generator providing a dedicated power source for the module. 43) A gas cylinder filling system as claimed in any of claims 27 to 42 wherein the system control module further comprises an electrical control panel.

44) A gas cylinder filling system as claimed in claim 43 wherein the gas cylinder filling system further comprises a power source connected to the electrical control panel of the system control module.

45) A gas cylinder filling system as claimed in either of claims 43 or 44 wherein the electrical control panel is configured to distribute power to the one or more gas supply modules.

46) A method of deploying a gas cylinder filling system the method comprising the steps of: -selecting one or more one or more gas supply modules as claimed in any of claims 1 to 24; -transporting the one or more gas supply modules to a required location for the gas cylinder filling system -connecting the one or more gas supply modules together at the required location.

47) A method of deploying a gas cylinder filling system as claimed in claim 46 wherein the method further comprises the steps of -selecting a system control module; -transporting the system control module to the required location; and -connecting the system control module to the one or more gas supply modules.