DRAINAGE SYSTEM

Abstract

A drainage system for draining fluid from a liquid storage tank and a method of draining a liquid storage tank using the drainage system, the drainage system comprising: a first conduit configured to fluidly connect to a liquid storage tank; a plurality of second conduits, each second conduit being fluidly connected to a measuring tank configured to hold liquid drained from the liquid storage tank; a multiway valve comprising: a first passage fluidly connected to the first conduit; a plurality of second passages, each second passage being fluidly connected to one of the plurality of second conduits; and a controllable shutter configured to selectively direct fluid between the first passage and the plurality of second passages; and a pump arranged to pump fluid through the first conduit.

Claims

1. A drainage system for draining fluid from a liquid storage tank, the drainage system comprising: a first conduit configured to fluidly connect to a liquid storage tank; a plurality of second conduits, each second conduit being fluidly connected to a measuring tank configured to hold liquid drained from the liquid storage tank; a multiway valve comprising: a first passage fluidly connected to the first conduit; a plurality of second passages, each second passage being fluidly connected to one of the plurality of second conduits; and a controllable shutter configured to selectively direct fluid between the first passage and the plurality of second passages; and a pump arranged to pump fluid through the first conduit.

2. The drainage system according to claim 1, wherein the multiway valve is a manually operated multiway valve that is configured to be operated by a user to control the controllable shutter to selectively direct fluid between the first passage and the plurality of second passages.

3. The drainage system according to claim 2, wherein the multiway valve is a multiway ball-valve comprising: a valve body comprising: the first passage; and the plurality of second passages; a ball shutter rotatably mounted in the valve body and configured to selectively direct fluid between the first passage and the plurality of second passages; and an actuator configured to rotate the ball shutter, wherein rotation of the ball shutter alters the direction of fluid between the first passage and the plurality of second passages.

4. The drainage system according to claim 3, wherein the actuator of the multiway ball-valve is a handle configured to be manually rotated by a user.

5. The drainage system according to claim 1, wherein each measuring tank comprises: a sampling outlet for draining fluid held in the measuring tank; and a sampling valve configured to control the drainage of fluid from the measuring tank through the sampling outlet.

6. The drainage system according to any claim 1, wherein each measuring tank comprises a level indicator configured to indicate the volume of liquid held in the measuring tank.

7. The drainage system according to claim 6, wherein each measuring tank comprises a minor portion and major portion, the minor portion having a smaller volume than the major portion and being fluidly connected to the major portion, and wherein the minor portion forms the level indicator, the minor portion comprising a viewing window configured to enable a user to see the volume of fluid held in the minor portion.

8. The drainage system according to claim 1, wherein the system further comprises a storage tank, and wherein each of the measuring tanks comprises: a drainage outlet fluidly connected to the storage tank for draining fluid from the measuring tank into the storage tank; and a drainage valve for controlling drainage of fluid from the measuring tank to the storage tank through the drainage outlet.

9. The drainage system according to claim 8, wherein each of the plurality of measuring tanks is configured to hold a first volume of fluid and wherein the storage tank is configured to hold a second volume of fluid, the second volume of fluid being at least as large as the sum of the first volumes of all of the measuring tanks.

10. The drainage system according to claim 8, wherein the system further comprises a three-way valve, the three-way valve comprising: a first passage fluidly connected to the first conduit; a second passage fluidly connected to the first passage of the multiway valve; a third passage fluidly connected to the drainage outlet of the storage tank; and a controllable shutter configured to selectively direct fluid between either the first conduit and the multiway valve or the first conduit and drainage outlet of the storage tank, and wherein the pump is arranged to pump fluid either through the first conduit to the multiway valve and the measuring tanks or from the drainage outlet of the storage tank through the first conduit and out of the system, depending on the selected direction of the controllable shutter of the three-way valve.

11. The drainage system according to claim 8, wherein the storage tank further comprises: a sampling outlet for draining fluid held in the storage tank; and a sampling valve configured to control the drainage of fluid from the storage tank through the sampling outlet.

12. The drainage system according to claim 1, wherein the drainage system is a drainage system for aircraft fuel tanks and wherein the first conduit is configured to fluidly connect to a drainage outlet of a fuel tank of an aircraft.

13. A vehicle comprising a drainage system according to claim 1.

14. A method of draining fluid from fuel tanks of an aircraft, the method comprising: providing a drainage system as claimed in claim 1; selecting a first fuel tank of an aircraft to be drained; selecting a first measuring tank of the drainage system to hold drained fluid from the selected first fuel tank of the aircraft; adjusting the multiway valve to direct fluid from the first conduit to the selected first measuring tank; fluidly connecting the first conduit of the drainage system to an outlet of the selected first fuel tank of the aircraft; and operating the pump of the drainage system to draw fluid from the selected first fuel tank of the aircraft through the first conduit and into the selected first measuring tank.

15. The method according to claim 14, wherein the method further comprises: selecting a second fuel tank of the aircraft to be drained; selecting a second measuring tank of the drainage system to hold drained fluid from the selected second fuel tank of the aircraft; adjusting the multiway valve to direct fluid from the first conduit to the selected second measuring tank; fluidly connecting the first conduit of the drainage system to an outlet of the selected second fuel tank of the aircraft; and operating the pump of the drainage system to draw fluid from the selected second fuel tank of the aircraft through the first conduit and into the second selected measuring tank.

16. The drainage system according to claim 1, wherein the multiway valve is a multiway ball-valve comprising: a valve body comprising: the first passage; and the plurality of second passages; a ball shutter rotatably mounted in the valve body and configured to selectively direct fluid between the first passage and the plurality of second passages; and an actuator configured to rotate the ball shutter, wherein rotation of the ball shutter alters the direction of fluid between the first passage and the plurality of second passages.

17. The drainage system according to claim 16, wherein the actuator of the multiway ball-valve is a handle configured to be manually rotated by a user.

18. The drainage system according to claim 9, wherein the system further comprises a three-way valve, the three-way valve comprising: a first passage fluidly connected to the first conduit; a second passage fluidly connected to the first passage of the multiway valve; a third passage fluidly connected to the drainage outlet of the storage tank; and a controllable shutter configured to selectively direct fluid between either the first conduit and the multiway valve or the first conduit and drainage outlet of the storage tank, and wherein the pump is arranged to pump fluid either through the first conduit to the multiway valve and the measuring tanks or from the drainage outlet of the storage tank through the first conduit and out of the system, depending on the selected direction of the controllable shutter of the three-way valve.

19. The drainage system according to claim 9, wherein the storage tank further comprises: a sampling outlet for draining fluid held in the storage tank; and a sampling valve configured to control the drainage of fluid from the storage tank through the sampling outlet.

20. The drainage system according to claim 10, wherein the storage tank further comprises: a sampling outlet for draining fluid held in the storage tank; and a sampling valve configured to control the drainage of fluid from the storage tank through the sampling outlet.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0064] Embodiments of the invention will now be described in detail, with reference to the accompanying drawings, in which:

[0065] FIG. 1 is a perspective view of a drainage cart according to a first embodiment of the present invention;

[0066] FIG. 2 is a plan view of the drainage cart of FIG. 1;

[0067] FIG. 3 is a side view of the drainage cart of FIG. 1;

[0068] FIG. 4 is an exploded view of a multiway valve of the drainage cart of FIG. 1;

[0069] FIG. 5 is a cross-sectional view of the shutter of the multiway valve of FIG. 4;

[0070] FIG. 6 is a cross-sectional view of the valve body of the multiway valve of FIG. 4;

[0071] FIG. 7 is a perspective view of a measuring tank of the drainage cart of FIG. 1; and

[0072] FIG. 8 is a side view of the measuring tank of FIG. 7.

DETAILED DESCRIPTION

[0073] FIG. 1 shows a drainage cart according to a first embodiment of the present invention.

[0074] The drainage cart 1 comprises a chassis 2 formed from lengths of mild steel box section welded into a substantially rectangular frame. The chassis 2 is supported at its corners on four wheels 3 that are rotatably secured to the chassis such that the chassis is movably supported on the wheels. A tow bar 4 is hingedly connected to the chassis 2, at the front end, such that the chassis 2 may be attached to a motorised vehicle, such as a tractor, and towed into position by the motorised vehicle.

[0075] A platform 6 is secured above the chassis 2. The platform 6 comprises a sheet steel deck on which a drainage system 100, according to an embodiment of the present invention, is mounted. The chassis 2, wheels 3 and platform 6 together form a trailer that movably supports the drainage system 100. Suitable steering trailers are currently available from the McMaster-Carr Supply Company.

[0076] The drainage cart 1 is configured to be towed by a separate motorised vehicle. However, it will be appreciated that in other embodiments the drainage cart may be a self-propelled vehicle and may comprise a motor or other suitable propulsion means.

[0077] It will also be appreciated that the drainage cart may have any other suitable number of wheels. For example, the vehicle may have two wheels, arranged towards the rear end of the chassis and legs or a rest at the front end on which the vehicle may be supported when the vehicle is stationary.

[0078] The drainage system 100, which is mounted on the platform 6, comprises a first conduit 102, measuring tanks 104, second conduits 106, a storage tank 108, a multiway valve 110 and a diaphragm pump 112.

[0079] The first conduit 102 comprises a hose pipe 114 and two purger pipes 116 that are releasably couplable to the hose pipe 114.

[0080] The hose pipe 114 comprises a flexible rubber hose that may be wound around a reel 118 when it is not in use. The reel 118 comprises a frame that is screwed to the platform 6 towards the front end of the cart. The hose pipe 114 comprises a first end having a coupler for fluidly connecting to one of the purger pipes 116 and a second end that is fluidly connected to the pump 112 and multiway valve 110. The coupler at the first end of the hose pipe 114 comprises a quick release latch (not shown) to enable quick removal of a purger pipe 116 from the hose pipe 114 and further comprises a ball-valve (not shown) for fluidly sealing the hose pipe 114 from a purger pipe 116.

[0081] The two purger pipes 116 comprise a first, long purger pipe and a second, short purger pipe. The long and short purger pipes are substantially identical apart from the lengths of the pipes. The long purger pipe is provided for draining fluid from the fuel tanks at the distal ends of the wings of an aircraft and the short purger pipe is provided for draining fluid from fuel tanks at or towards the fuselage of an aircraft. The purger pipes 116 may have any suitable length, but typically the short purger pipe has a length of about 610 mm (about 24 inches) and the long purger pipe has a length of about 1830 mm (about 72 inches).

[0082] Each purger pipe 116 comprises a substantially rigid aluminium pipe having a first end comprising a coupling for fluidly coupling the purger pipe 116 to a drainage valve of a fuel tank of an aircraft and a second end, opposite the first end, comprising a coupling for fluidly coupling to the first end of the hose pipe 114. A plurality of clips 117 are screwed onto the platform 6 along one side of the platform 6, for holding the purger pipes 116 in an easily accessible position on the drainage cart when the first conduit 102 is not in use and the purger pipes 116 are disconnected from the hose pipe 114.

[0083] The second end of the hose pipe 114 is fluidly connected to the multiway ball valve 110 via the pump 112. More specifically, the second end of the hose pipe 114 is fluidly connected to a first three-way valve 128. The first three-way valve 128 comprises a T-junction 130 comprising a first end fluidly connected to the second end of the hose pipe 114, a second end fluidly connected to a first ball-valve 131 and a third end fluidly connected to a second ball-valve 132. A pipe 133 fluidly connects the first ball-valve 131 of the first three-way valve 128 to a second three-way valve 134 at the inlet of the pump 112. The second three-way valve 134 comprises a T-junction 136 comprising a first end fluidly connected to the inlet of the pump 112, a second end fluidly connected to a first ball-valve 137 and a second end fluidly connected to a second ball-valve 138. The outlet of the pump 112 is fluidly connected to a third three-way valve 142. The third three-way valve 142 comprises a first end fluidly connected to the outlet of the pump 112, a second end fluidly connected to a first ball-valve 145 and a third end fluidly connected to a second ball-valve 146. A pipe 147 fluidly connects the first ball-valve 145 of the third three-way valve 142 to the multiway valve 112.

[0084] When the first ball-valves 131, 137, 145 of the three three-way valves 128, 134, 142 are open, and the second ball-valves 132, 138, 146 of the three three-way valves 128, 134, 142 are closed, a continuous path is formed along which fluid may flow between the first end of the first conduit 102, the pump 112 and the multiway valve 110.

[0085] In this embodiment, all of the ball-valves are manually operated ball valves, having handles that may be rotated by a user to open or close the valve. It will be appreciated that the ball valves may be any other suitable type of valve. It will be appreciated that the three-way valves may be any other suitable type of three-way valve. It will also be appreciated that the valves and fittings of the drainage system 100 may be any suitable size and may be made from any suitable material, such as brass, aluminium or plastic.

[0086] The pump 112 is a gas powered diaphragm pump that is driven by a compressed nitrogen source, in the form of a cylinder 148. The compressed nitrogen source forms part of the drainage system 1 and is secured in a holder that is screwed to the platform 6. It will be appreciated that the pump may be driven by a compressed air source or any other suitable compressed gas source. It will also be appreciated that the pump may be driven from an external compressed gas source. Both the nitrogen cylinder 148 and the inlet to the pump comprise regulators (not shown) for controlling the pressure delivered to the pump.

[0087] The pump 112 is mounted in a stand 149 formed from welded lengths of mild steel angle section. The stand is secured to the platform 6 with screws. The stand 149 extends above the pump 112 to a height of about 585 mm (about 23 inches) from the platform 6, and includes a substantially vertical mounting plate formed from mild steel sheet supported above the pump 112, on which the multiway valve 110 is secured.

[0088] The multiway valve 110 is shown in FIGS. 4 to 6. The multiway valve 110 generally comprises a valve body 150, a ball shutter 152, a holding plate 154 and a handle 156.

[0089] The valve body 150 is formed from a single piece of brass and comprises a substantially cylindrical body having planar top face 160, a planar bottom face 161 and twelve substantially planar side faces 162. The side faces 162 extend between the top and bottom faces 160, 161 and are substantially perpendicular to the top and bottom faces 160, 161.

[0090] The valve body 150 further comprises a substantially circularly cylindrical central cavity 164 for rotatably receiving the ball shutter 152. A first passage 166 extends between the front face 160 and the cavity 164 of the valve body 150. Second passage 168 extend between alternate side faces 162 and the cavity 164, substantially perpendicular to the direction of the first passage 166. The second passages 168 are arranged to extend substantially in a plane that is substantially perpendicular to the direction of the first passage 166. A rear passage 169 is also provided for inserting the shutter valve 152 into the cavity 164. The rear passage 169 extends between the rear face 161 and the cavity 164 and has a diameter that is substantially similar to the diameter of the cavity 164.

[0091] The first passage 166 and the second passages 168 are substantially identical and are configured to be fluidly coupled to flexible hose pipes. The passages 166 and 168 have a first narrow portion towards the cavity 164, and a second wide portion towards the face of the valve body 150. The second wide portion is threaded and configured to receive an end of a threaded pipe insert (not shown). The opposite ends of the threaded pipe inserts are configured to be inserted into an end of a hose pipe, with an interference fit, and to be clamped to the hose pipe by an external clamp (not shown) arranged over the end of the hose pipe. It will be appreciated that the first and second passages of the valve body 150 may be configured for use with any other suitable means for securing and fluidly connecting hose pipes to the passages.

[0092] The ball shutter 152 comprises a substantially circularly cylindrical brass body, having a shutter part 170 and an axel part 172 arranged substantially along a central axis A. The shutter part 170 is has substantially the same diameter as the cavity 164 and the rear passage 169 of the valve body 150, such that the shutter part 170 may be closely received in the cavity 164 of the valve body 150. The axel part 172 has a diameter that is narrower than the shutter part 170 and a length that is sufficient for the axel part 172 to extend out of the rear passage 169 when the shutter part 170 is fully received in the cavity 164.

[0093] The shutter part 170 has an L-shaped channel 174 extending between a front face 175 and a side face 176. A first section 177 of the L-shaped channel 174 extends into the first shutter part 170 from the front face 175 and is aligned with the axis A of the shutter 152. A second section 178 of the L-shaped channel 174 extends into the first shutter part 170 from the side face 176 and joins the first portion 177 to form a continuous L-shaped channel.

[0094] The axel part 172 comprises a square distal tip 179, comprising a square receiving portion for receiving a square cavity (not shown) of the handle 156. The square shape of the distal tip 179 of the axel part 172 and the cavity of the handle 156 enables rotation of the handle 156 about the axis A to cause rotation of the axel part 172 of the shutter 152 about the axis A. This in turn causes rotation of the shutter part 170 of the shutter 152 about the axis A.

[0095] The holding plate 154 is a substantially circular plate made of brass, with a diameter that is substantially similar to the diameter of the valve body 150. The holding plate 154 has a central aperture 180 with a width that is substantially similar to the width of the axel part 172 of the shutter 152, which enables the axel part 172 to extend through the central aperture 180 when the holding plate is arranged over the valve body 150.

[0096] To assemble the multiway valve 110, the first shutter part 170 of the ball shutter 152 is inserted into the cavity 164 of the valve body 150 via the rear passage 169 until the front face 175 of the shutter valve 152 abuts the front end of the cavity 164. In this position, the first portion 177 of the L-shaped channel 174 of the shutter 152 is aligned with the first passage 166 of the valve body 150. The second axel part 172 of the ball shutter 152 extends out of the rear passage 169 of the valve body 150 and the holding plate 154 is arranged against the bottom face 161 of the valve body 150, with the axel part 172 of the shutter 152 extending through the central aperture 180. The holding plate 154 is secured against the bottom face 161 of the valve body 150, with screws, and the holding plate 154 retains the shutter 152 in the cavity 164 of the valve body 150. The handle 156 is arranged on the axel part 172 of the shutter 152, with the square tip 179 of the axel part 172 received in the square cavity of the handle 156. The handle 156 is then secured on the axel part 172 with screws.

[0097] When the multiway valve is assembled, the handle 156 may be rotated about the central axis A of the ball shutter 152, and the rotation may cause the second portion 178 of the L-shaped channel 174 to rotate about the inner surface of the cavity 164 and align the second portion 178 with each of the second passages 168 of the valve body 150, whilst the first portion 177 of the L-shaped channel 174 maintains its alignment with the first passage 166 of the valve body 150. As such, a user may rotate the handle 156 of the multiway valve 110 to select which of the second passages 168 of the valve body 150 is aligned with the second portion 178 of the L-shaped channel 174 of the ball shutter 152. Alignment of the second portion 178 of the L-shaped channel 174 with a second passage 168 provides fluid connection between the first passage 166 of the valve body 150 and the aligned second passage 168 of the valve body 150.

[0098] The drainage system 100 comprises six measuring tanks 104. The number of measuring tanks 104 corresponds to the number of fuel tanks provided on the aircraft that the drainage system 100 is to be used, for example, a Boeing 787-9. It will be appreciated that in other embodiments the number of measuring tanks may be increased or decreased to meet the requirements of the aircraft with which it is to be used.

[0099] Each measuring tank 104 forms a substantially cuboidal hollow metallic shell, formed from welded stainless steel sheet to form a liquid tight container. Each measuring tank 104 is about 304.8 mm (12 inches) wide, about 304.8 mm (12 inches) long and about 254 mm (10 inches) high. As such, each measuring tank 104 can hold about 23 litres of fluid.

[0100] Each measuring tank 104 has an inlet 190 at the upper face, the inlet 190 being fluidly connected to one of the second passages 168 of the multiway ball valve 110 by a second conduit 106. Each second conduit 106 comprises a flexible rubber hose, substantially similar to the flexible hose 114 of the first conduit 102. A first end of each second conduit 106 is fluidly connected to an inlet of a measuring tank 104 and a second end of each second conduit 106 is fluidly connected to a second passage 168 of the multiway ball valve, substantially as described above. As such, when the shutter 152 of the multiway ball valve 110 is rotated to select a second passage 168, the selected second passage 168 is fluidly connected to a measuring tank 104. The second conduits are secured to the platform with clips, where necessary, to prevent the second conduits 106 from moving and disconnecting from the inlets of the measuring tanks 104 or the second passages 168 of the multiway valve 110.

[0101] Each measuring tank 104 comprises outlets 192 depending from an underside, the outlets 192 comprising a sampling outlet 193 and a drainage outlet 194. The sampling outlet 193 comprises a miniature ball valve (not shown) and the drainage outlet 194 comprises a ball valve 195, such that fluid held in the measuring tank 104 may be retained in the measuring tank or drained either through the sampling outlet 193 or the drainage outlet 194 depending on the orientations of the miniature ball valve and the ball valve 195.

[0102] Each measuring tank 104 also comprises a liquid level indicator 197 comprising a clear pipe secured to an outer side of the container, and fluidly connected to the internal volume of the container. A scale (not shown) indicating liquid level in the internal volume of the measuring tank is marked on the outer side of the tank, next of the clear pipe, such that when liquid is held in the measuring tank, the liquid level in the pipe may align with an indicator on the scale, the indicator corresponds to the volume of liquid that is held in the measuring tank.

[0103] Since the density of water is typically greater than the density of aircraft fuel, when a mixture of fuel and water is held in the measuring tank, the fuel and water tend to separate, and the fuel tends to rise above the water. As such, it may be possible to drain the water from the bottom of the measuring tanks 104 through the sampling outlets 193 at the underside of the measuring tanks 104. In addition, the separation of the water and fuel in the measuring tanks 104 may enable a user to determine both the volume of water and the volume of fuel held in the measuring tank from a visual inspection of the liquid level indicator 197. Furthermore, a user may be able to control the drainage of water from the measuring tanks 104 through the sampling outlets 193 by controlling the opening of the miniature ball valves based on a visual inspection of the liquid level indicator 197. In other words, a user may be able to see a line of separation between the water and fuel held in a measuring tank 104 in the liquid level indicator 197. The user may be able to drain fluid from the measuring tank 104 through the sampling outlet 193 by opening the miniature ball valve. The user may maintain the miniature ball valve in the open position until the line of separation is no longer visible, which may indicate that all the water has been drained from the measuring tank 104. The user may then close the miniature ball valve to stop drainage of fluid from the measuring tank 104 through the sampling outlet 193.

[0104] It will be appreciated that in some embodiments, the scale indicating liquid level in the internal volume of the measuring tank may be marked directly on the pipe. It will also be appreciated that the liquid level indicator may be any other suitable type of liquid level indicator.

[0105] The drainage system further comprises a storage tank 108. The storage tank has a substantially similar construction to the measuring tanks 104, forming a substantially cuboidal hollow metallic shell formed from welded stainless steel sheet to form a liquid tight container. However, the storage tank 108 is considerably larger than the measuring tanks 104. The storage tank 108 is about 1130.3 mm (44.50 inches) wide, about 1320.8 mm (52.00 inches) long and about 241.3 mm (9.5 inches) high. As such, the storage tank 108 can hold about 360 litres of fluid. Therefore, the storage tank 108 has a sufficient volume to hold at least the volume of fluid held in all of the measuring tanks.

[0106] The storage tank 108 is supported above the platform 6 on three mild steel U-channel sections (not shown) that are secured to the platform 6 with screws. The U-channel sections extend substantially in the direction of the width of the platform 6 and are spaced along the length of the platform 6 to support the front, rear and centre of the storage tank 108.

[0107] The measuring tanks 104 are arranged directly above the storage tank 108, each measuring tank 104 being supported on a stand formed from mild steel angle section. The stands raise the measuring tanks about 254 mm (10 inches) above the storage tank 108. The stands provide sufficient space for the ball valve sampling outlet 193, drainage outlet 194 and ball valve 195 to depend from the measuring tanks 104.

[0108] The drainage outlets 194 of the measuring tanks 104 are fluidly connected to the storage tank 108, via six inlets in the upper face of the storage tank 108. As such, when the ball valves 195 of the measuring tanks 104 are oriented to permit fluid to flow out of the measuring tank through the drainage outlet 194, the fluid drains out of the measuring tank 104 and into the storage tank 108.

[0109] The storage tank 108 also has a liquid level indicator as provided on the measuring tanks 104.

[0110] The storage tank 108 has a drainage outlet 200 through which fluid held in the storage tank 108 may be drained. The drainage outlet 200 of the storage tank 108 is fluidly connected to the first conduit 102, via the pump 112. More specifically, a pipe 202 fluidly connects the drainage outlet 200 of the storage tank 108 to the inlet of the pump 112. One end of the pipe 202 is fluidly connected to the drainage outlet 200 of the storage tank 108 and the other end of the pipe 202 is fluidly connected to the second ball valve 138 of the second three-way valve 134. The second ball valve 138 of the second three-way valve 134 is fluidly connected to the second end of the T-junction 136 and the first end of the T-junction 136 is fluidly connected to the inlet of the pump 112. A pipe 204 fluidly connects the outlet of the pump 112 to the second end of the hose pipe 114 of the first conduit 102. One end of the pipe 204 is fluidly connected to the second ball valve 146 of the third three-way valve 142. The second ball valve 146 of the third three-way valve 142 is fluidly connected to the second end of the T-junction 144 and the first end of the T-junction 144 is fluidly connected to the outlet of the pump 112. The other end of the pipe 204 is fluidly connected to the second ball valve 132 of the first three-way valve 128. The second ball valve 132 of the first three-way valve 128 is fluidly connected to the second end of the T-junction 130 and the first end of the T-junction 128 is fluidly connected to the second end of the hose pipe 114 of the first conduit 102.

[0111] When the second ball-valves 132, 138, 146 of the three three-way valves 128, 134, 142 are open, and the first ball-valves 131, 137, 145 of the three three-way valves 128, 134, 142 are closed, a continuous path is formed along which fluid may flow between the drainage outlet 200 of the storage tank 108, the pump 112 and the first end of the first conduit 102.

[0112] The arrangement of the pump 112 and the three three-way valves 128, 134, 142 configures the drainage system 100 to either: [0113] 1. pump fluid from an aircraft fuel tank through the first conduit 102 and into a selected measuring tank 104, via the multiway valve 110, when the first ball-valves 131, 137, 145 of the three three-way valves 128, 134, 142 are open and the second ball-valves 132, 138, 146 of the three three-way valves 128, 134, 142 are closed; or [0114] 2. pump fluid from the storage tank 108 through the drainage valve 200 and out of the system 100 through the first conduit 102, when the second ball-valves 132, 138, 146 of the three three-way valves 128, 134, 142 are open, and the first ball-valves 131, 137, 145 of the three three-way valves 128, 134, 142 are closed.

[0115] The storage tank 108 further comprises a sampling valve 205. The sampling outlet 205 is substantially similar to the sampling outlets 193 of the measuring tanks 104, and comprises a ball valve (not shown) for selectively enabling drainage of fluid form the storage tank 108 through the sampling outlet 205.

[0116] It will be appreciated that the drainage cart may also comprise other components, devices or systems mounted on the platform that may be complimentary to or separate from the drainage system.

[0117] In this embodiment, the drainage cart 1 further comprises: a fire extinguisher cabinet 210 secured to the platform 6, housing a fire extinguisher (not shown); a toolbox 212 secured to the platform 6; a storage box 214 secured to the platform 6; and a cabinet 216 secured to the platform 6.

[0118] It is envisaged that in some embodiments, a personal computer may be housed in the cabinet 216 and may be used for inputting fuel and water testing results into a database. The personal computer may be connected to a network via a wireless network for updating a remote database whilst the drainage cart is in the field.

[0119] The drainage cart 1 also comprises grounding cables (not shown) secured to the chassis, for connecting to grounding points on an aircraft that is to be defueled and to grounding points on the ground.

[0120] In some embodiments, the system may comprise one or more sensors or meters for sensing or measuring parameters of the system. For example, the system may comprise a fuel totalizer for measuring the volume of fuel and/or water that passes through the conduits. A fuel totalizer may be removably couplable to the first conduit 102, particularly between the hose pipe 114 and the purger pipes 116. Similarly, a flow rate meter may be provided for measuring the flow rate of fuel and/or water through the conduits. The flow rate meter may also be couplable to the first conduit 102, between the hose pipe 114 and the purger pipes 116. A flow rate meter may be provided as a separate device to the fuel totalizer or the flow rate meter and the fuel totalizer may be provided as part of a single integrated device. Any number of sensors or meters may be provided in the system. Each sensor or meter may be fixedly coupled to one or more parts of the system or may be removably couplable to one or more parts of the system. The one or more sensors or meters may be provided with any suitable output for outputting the sensed or measured data. Preferably, the one or more sensor or meters comprise a digital screen for displaying the sensed or measured data. Ideally, in embodiments comprising a computer housed in the cabinet 216, the one or more sensors or meters may be coupled or connected to the computer for sending or transmitting the sensed or measured data to the computer.

[0121] Various exemplary procedures for operating the drainage cart 1 and drainage system 100 will now be described. It will be appreciated that other procedures may also be employed to operate the drainage system 100, and that the described procedures are exemplary procedures only.

[0122] The procedure for draining fluid from a liquid storage tank using the drainage cart 1 may comprise: [0123] 1. towing the drainage cart 1 into position proximate an aircraft with fuel tanks to be drained; [0124] 2. applying brakes on the wheels (not shown) and positioning wheel chocks under each wheel to immobilize the cart 1; [0125] 3. attaching a ground cable of the cart 1 to a grounding point on the aircraft and attaching another ground cable of the cart 1 to a grounding point on the ground; [0126] 4. coupling the second end of one of the purger pipes 116 to the first end of the hose pipe 114 via the quick release coupling (select the shorter purger pipe for draining fluid from tanks at and close to the fuselage and select the longer purger pipe for draining fluid from tanks at distal ends of the wings); [0127] 5. selecting a fuel tank to be drained and a measuring tank 104 into which fluid from the selected fuel tank is to be drained; [0128] 6. rotating the handle 156 on the multiway valve 110 to select the desired measuring tank; [0129] 7. setting the three first ball valves 131, 137, 145 of the three three-way valves 128, 134, 142 to the open position and setting the three second ball valves 132, 138, 146 to the closed position; [0130] 8. coupling the coupler at the first end of the purger pipe 116 to the drain valve of the selected fuel tank; [0131] 9. checking for leaks between the coupler and the fuel tank drain valve; [0132] 10. opening the ball valve between the purger pipe 116 and the hose pipe 114; [0133] 11. opening the nitrogen cylinder valve and setting the nitrogen cylinder regulator to about 50 psi (about 3.5 bar); [0134] 12. checking the pressure of the pump regulator is at about 35 psi (about 2.5 bar); [0135] 13. running the nitrogen powered diaphragm pump 112 to drain fluid from the selected aircraft fuel tank into to the selected measuring tank 104; and [0136] 14. inspecting the liquid level indicator 197 of the selected measuring tank to ensure that the selected measuring tank is not over filled; and [0137] 15. once a sufficient volume of fluid is drained from the aircraft fuel tank or once the aircraft fuel tank has been emptied of fluid, closing the nitrogen cylinder valve to shut down the pump 112.

[0138] The process for disconnecting the drainage cart 1 from an aircraft fuel tank and preparing the cart 1 to be towed may comprise: [0139] 1. closing the ball valve between the coupler between the hose pipe 114 and the purger pipe 116; [0140] 2. closing the nitrogen cylinder valve to stop the pump 112 operating; [0141] 3. disconnecting the coupling at the first end of the purger pipe 116 from the drain valve of the aircraft fuel tank; [0142] 4. setting the three first ball valves 131, 137, 145 of the three three-way valves 128, 134, 142 to the closed position and checking that the three second ball valves 132, 138, 146 remain in the closed position; [0143] 5. disconnecting the purger pipe 116 and the hose pipe 114; [0144] 6. disconnecting the ground cables from the grounding points on the aircraft and the ground; and [0145] 7. removing the chocks and releasing the brakes to ready the cart 1 to be towed.

[0146] The process for sampling or draining water from a measuring tank 104 may comprise: [0147] 1. selecting the measuring tank 104 to be drained; [0148] 2. arranging a suitable sampling container below the sampling outlet 193 of the selected measuring tank 104; [0149] 3. rotating the ball valve 193 of the selected measuring tank 104 to select the sampling outlet 193 to drain fluid from the measuring tank 104 through the sampling outlet 193; [0150] 4. inspecting the liquid level indicator 197 to ensure that sufficient water has been drained from the measuring tank 104; [0151] 5. rotating the ball valve 193 of the selected measuring tank 104 to stop fluid from draining from the measuring tank 104 through the sampling outlet 193.

[0152] The process for sampling or draining water from the storage tank 108 may be substantially similar to the process for sampling or draining water from the measuring tanks 104.

[0153] The process for draining a selected measuring tank 104 into the storage tank 108 may comprise: [0154] 1. selecting the measuring tank 104 to be drained; [0155] 2. rotating the ball valve 195 of the selected measuring tank 104 to select the drainage outlet 194 in order to drain fluid from the measuring tank 104 through the drainage outlet 194; [0156] 3. inspecting the liquid level indicator 197 of the selected measuring tank 104 to determine when no fluid remains in the selected measuring tank 104; and [0157] 4. rotating the ball valve 195 of the selected measuring tank 104 to stop fluid from draining from the measuring tank 104 through the drainage outlet 194.

[0158] The process for draining the storage tank 108 of fluid may comprise: [0159] 1. setting the three first ball valves 131, 137, 145 of the three three-way valves 128, 134, 142 to the closed position and setting the three second ball valves 132, 138, 146 to the open position; [0160] 2. opening the nitrogen cylinder valve and setting the nitrogen cylinder regulator to about 50 psi (about 3.5 bar); [0161] 3. checking the pressure of the pump regulator is at about 35 psi (about 2.5 bar); [0162] 4. running the nitrogen powered diaphragm pump 112 to drain fluid from the storage tank through the hose pipe 114; [0163] 5. inspecting the liquid level indicator on the storage tank 108 to ensure that a sufficient volume of fluid is drained from the storage tank 108; and [0164] 6. once a sufficient volume of fluid is drained from the storage tank 108 or once the storage tank 108 has been emptied of fluid, closing the nitrogen cylinder valve to shut down the pump 112.

[0165] It will be appreciated that the example described herein is a straightforward example, and that modifications may be made to the illustrated drainage system to provide different functionality. It will be appreciated that features described herein with reference to the described embodiment may be applied to other embodiments without departing from the scope of the invention.