Device for checking the positioning of a pad against a housing base for maintaining a pumping tower.

Abstract

Title of the invention: Device for checking the positioning of a pad against a housing bottom for holding a pumping tower. The present invention relates to a device for holding and guiding a pumping tower (1) for loading or unloading liquid gas from a liquid gas storage tank (4), in which a first element (60) and a second element (61) cooperate by means of a pad (326) housed in a housing (322) carried by one or other of the first element (60) or the second element (61). The first element (60) or the second element (61) which carries the pad (326) then comprises a checking device (325) allowing the position of the pad (326) to be viewed in its housing (322).

Description

Title of the invention: Device for checking the positioning of a pad against a housing bottom for maintaining a pumping tower.

[0001] The present invention relates to a means for blocking a pumping tower at the bottom of a tank, for loading or unloading liquid and more particularly the loading or unloading of a gas transported in the liquid state in ship tanks.

[0002] Liquefied natural gas, commonly known by the acronym "LNG" or "Liquefied Natural Gas", is an important energy source, composed of approximately 90% methane. LNG is stored in the liquid state in a thermally insulated tank at a temperature close to -160°C, the LNG then occupying 1 / 600 of the volume that it would occupy in the gaseous state, thus facilitating transport between a loading site and an unloading site for LNG. During its transport, the LNG is stored in a sealed and thermally insulating tank.

[0003] In order to load and unload the sealed tank in which the LNG is stored, a pumping tower is installed therein, and this pumping tower is then fixed directly to a base anchored in the bottom of the tank. The tank therefore comprises an opening configured to receive the pumping tower and the latter can then comprise several masts extending over the entire height of the tank.

[0004] During loading and unloading of the tank, significant temperature variations can expand or contract the materials used in the pumping tower. It is then necessary for the pumping tower to be able to slide along the base in order to adapt to these temperature variations.

[0005] Skids are used to allow this vertical translational movement on the base fixed to the bottom of the tank, while maintaining the pumping tower transversely relative to the base. Skid supports are then fixed under the pumping tower so that the skids are positioned opposite the base allowing the pumping tower to slide along the latter. Adequate mounting of the skid supports under the pumping tower is then necessary in order to obtain sufficient contact between the base and the skids. However, a disadvantage lies in the fact that the skid is hidden by its support, which significantly complicates the verification that the operator must carry out, to ensure the correct position of the skid relative to the base.

[0006] The present invention therefore aims to overcome the drawback stated above by designing a simple and reliable means of verifying the position of the skate in its support.

[0007] The invention therefore relates to a device for holding and guiding a pumping tower for loading or unloading liquid gas from a liquid gas storage tank, comprising at least one first element configured to be secured to the tank, at least one second element configured to be secured to the pumping tower and at least one pad positioned between the first element and the second element so that it slides against the first element or the second element, the first element or the second element providing a housing delimited by a housing bottom and a frame, the pad being arranged in the housing, characterized in that the first element or the second element comprises at least one device for verifying the contact between the pad and the housing bottom.

[0008] The verification device allows for a naked-eye check of the position of the pad in its housing, and more particularly of the contact between the pad and the bottom of the housing, by an operator, visually or via a verification tool.

[0009] According to a characteristic of the invention, the first element comprises the housing which receives the skate and the second element comprises a support against which the skate slides.

[0010] According to an alternative characteristic of the invention, the second element comprises a support in which the housing which receives the pad is arranged, the first element comprising at least one sliding face against which the pad slides. In one example of the invention, the second element is said support.

[0011] According to a characteristic of the invention, the verification device comprises at least one groove provided in the frame and which connects the housing to an environment external to the housing. The groove thus allows the operator to obtain a visual view with the naked eye of the housing in which the skate is positioned.

[0012] According to a characteristic of the invention, the verification device comprises at least one groove provided in a lateral edge of the frame and which connects the housing to an environment external to the housing.

[0013] According to a characteristic of the invention, the verification device comprises at least one groove provided in a longitudinal edge of the frame and which connects the housing to an environment external to the housing.

[0014] According to a characteristic of the invention, the support comprises two grooves, each arranged on either side of a longitudinal or vertical median plane of the pad.

[0015] According to a characteristic of the invention, the support comprises four grooves each provided two by two in a lateral edge of the frame.

[0016] According to a characteristic of the invention, the groove passes through a thickness of the frame. This thickness is measured along a straight line perpendicular to the bottom of the housing. This characteristic facilitates the manufacture of the groove.

[0017] According to a characteristic of the invention, the groove has a groove bottom which is arranged between a rear face of the frame and the housing bottom.

[0018] According to a characteristic of the invention, the bottom of the groove is coplanar with the housing bottom.

[0019] According to a characteristic of the invention, the pad is made of a sliding material, for example polytetrafluoroethylene. Such a material has the advantage of being both chemically inert and having a low coefficient of friction, allowing it to resist many chemical products and to be self-lubricating.

[0020] According to a characteristic of the invention, the verification device comprises at least one through hole provided in the housing bottom. The hole then makes it possible to verify that the pad is properly against the housing bottom.

[0021] According to another example, the verification device is a gel or liquid capsule, arranged between the pad and the housing bottom and which bursts under the pressure exerted by the positioning of the pad against the housing bottom. The flow of the gel or liquid allows the operator to attest to the contact between the pad and the housing bottom.

[0022] According to yet another exemplary embodiment, the verification device is a mechanical or electrical contact sensor, which can emit a signal, for example audible or luminous, upon contact between the pad and the housing bottom.

[0023] The invention also covers a liquid gas storage tank comprising a pumping tower for loading or unloading liquid gas, a base secured to a bottom wall of the tank, the pumping tower being held and guided relative to the base by a holding and guiding device according to any one of the preceding characteristics, the base comprising a first portion fixed to the bottom wall of the tank and a second portion comprising at least the first element.

[0024] The invention also covers a liquid natural gas transport vessel comprising at least one device for holding and guiding a pumping tower according to the preceding characteristics or at least one tank according to the preceding characteristic.

[0025] The invention also comprises a system for loading or unloading liquid natural gas which combines at least one land-based means and at least one liquid natural gas transport vessel according to the preceding characteristic.

[0026] The invention also covers a method of mounting a pumping tower in a tank during which, in a first step, the pumping tower is placed inside the tank, in a second step, the pumping tower is held on a base secured to the bottom of the tank by means of a holding and guiding device according to any one of the preceding characteristics, characterized in that during a third step, we check the contact between the pad and the bottom of the housing.

[0027] Finally, the invention covers a method for loading or unloading liquid natural gas from a tank according to the characteristics of the tank mentioned above or from a liquid natural gas transport vessel according to the characteristics of the vessel mentioned above.

[0028] Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows on the one hand, and several exemplary embodiments given for informational and non-limiting purposes with reference to the appended schematic drawings on the other hand, in which: - Figure [Fig. 1] is a general perspective view of a liquid gas transport vessel comprising four tanks, each equipped with a pumping tower comprising the invention; - Figure [Fig. 2] is a general perspective view of the pumping tower of Figure 1 with an upper end and a lower end incorporating a support plate; - Figure [Fig. 3] is a perspective view of a portion of the lower end of the pumping tower of Figure 2, showing the cooperation between a first element and second elements; - Figure [Fig. 4] is a close-up perspective view of one of the second elements of Figure 3 fixed to one of the feet of the pumping tower; - Figure [Fig. 5] is an exploded perspective view of the second element and the foot of the pumping tower of Figure 4; - Figure [Fig. 6] is a vertical sectional view of a verification device according to one of the embodiments of the invention; - Figure [Fig. 7] is a vertical sectional view of a verification device according to another embodiment of the invention.

[0029] The features, variants and different embodiments of the invention may be combined with each other, in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0030] In Figure 1 is shown a ship 0, for example a methane tanker, which has four tanks 4 for storing liquefied gas. Each tank 4 is associated with a pumping tower 1 which allows at least the extraction of the liquefied gas from the tank 4. The tanks 4 are separated from each other by double transverse partitions 42, otherwise called "cofferdam". Each of the tanks 4 is formed by a super position of a primary insulation layer and a secondary insulation layer, otherwise called respectively primary membrane and secondary membrane.

[0031] An opening is provided in an upper wall 41 of the tank 4 in order to allow the pumping tower 1 to pass into the enclosure of the tank 4, in particular during its installation. A first element 60, taking the form of a base 2, secured to a bottom wall 40 of the tank 4, allows the pumping tower 1 to be accommodated in the tank 4.

[0032] A cover 11, notably visible in FIG. 2, extending parallel to the upper wall 41 of the tank 4, then makes it possible to close the opening of this upper wall 41 of the tank 4 and to make the tank 4 watertight and thermally insulating.

[0033] The pumping tower 1, visible in Figure 2, comprises an upper end 12 at which the cover 11 is positioned, and a lower end 14, opposite the upper end 12, in a vertical direction V of the pumping tower 1. At least one mast 10 extends from the upper end 12 to the lower end 14 of the pumping tower 1. The mast 10 consists of a hollow rod, preferably made of stainless steel, and of circular radial section. Inside at least one of the masts 10 extends a liquid gas discharge tube 18 from the lower end 14 of the pumping tower 1 to the upper end 12 of the pumping tower 1, such that it emerges from the cover 11 outside the tank. The end of the unloading tube 18 which is external to the tank 4 can thus be connected to an external unloading device which can be part of unloading means located on land.

[0034] The pumping tower 1 comprises a base plate 16 which extends parallel to the cover 11, at the lower end 14 of the pumping tower 1. The base plate 16 comprises an upper face 161 facing the cover 11, and a lower face 162 facing the base 2. Tower feet, notably visible in FIG. 3, are fixed to the lower face 162 of the base plate 16. Preferably, the tower feet are welded to the lower face 162 of the base plate 16 and are configured to cooperate with the base 2, by means of support, also visible in FIG. 3.

[0035] Figure 2 also illustrates the presence of two unloading pumps 50 carried by the base plate 16 and arranged in the vicinity of the lower end 14 of the pumping tower 1.

[0036] Figure 3 shows an exemplary embodiment of the invention in which the device for holding and guiding the pumping tower comprises the first element 60 in the form of the base 2 and a second element 61 in the form of a support 32. In this embodiment, the support 32 has a housing in which a pad is housed, visible in Figures 4 and 5, and the base 2 comprises a sliding face 25 on which the pad slides in the vertical direction V of the pumping tower. Figure 3 then illustrates a perspective view of the cooperation between the first element 60 and the second element 61.

[0037] According to another embodiment of the invention not illustrated, the position of the housing and the sliding plate could be reversed, that is to say that the sliding plate is carried by the second element and the housing is carried by the first element.

[0038] The base 2 is partly anchored in the bottom wall 40 of the tank and comprises a first part 20 immersed in the bottom wall 40 of the tank and a second part 22, emerging from the bottom wall 40 of the tank. The base 2 is thus anchored in the bottom wall 40 of the tank in order to provide sufficient support for the pumping tower when the latter is positioned on the base 2.

[0039] The first part 20 of the base 2 has a truncated cone shape and is welded into the bottom wall 40 of the tank. By truncated cone, it is meant that its diameter decreases as it approaches the bottom wall 40 of the tank. The second part 22 of the base 2 extends into the enclosure of the tank and has a proximal end 201, closest to the bottom wall 40 of the tank, and a distal end 202, furthest from the bottom wall 40 of the tank. The proximal end 201 has a truncated cone shape, in continuity with the first part 20 of the base 2, while the distal end 202 has a cylindrical, in particular circular, shape.

[0040] The second base portion 22 comprises a first arm 221 and a second arm 222 which extend along the same straight line from the distal end 202 of the second portion 22 of the base 2. The first arm 221 is predominantly rectangular, with the exception of a first side 224a in contact with the distal end 202 of the base 2, the first side 224a having a curved shape in order to match the cylindrical shape of the distal end 202 of the base 2. A second side 224b and a third side 224c, parallel to each other, extend from the first side 224a and a fourth side 224d extends perpendicular to the second side 224b and to the third side 224c, such that it connects them.

[0041] At least one of the free sides of the first arm 221, i.e. the second side 224b, the third side 224c or the fourth side 224d corresponds in this embodiment of the invention to the sliding face 25 on which the pad slides.

[0042] The structural characteristics mentioned for the first arm 221 also apply to the second arm 222.

[0043] The supports 32 are positioned opposite the sliding faces 25 defined by the free sides of the first arm 221, i.e. the second side 224b, the third side 224c and the fourth side 224d. At least one of the supports 32 above makes it possible to house the pad, notably visible in FIG. 4. A verification device 325 is provided on the second element 61, i.e. on the support 32, such that it makes it possible to check by eye or using a verification tool, the correct installation of the pad in the housing provided in the support 32, for example by means of a groove 340 or a hole 350.

[0044] The supports 32 are associated with the feet 30 of the base plate. The support 32, the verification device 325 as well as the foot 30 will be explained in more detail in the description of FIG. 4 and FIG. 5.

[0045] It is understood that the characteristics mentioned previously with regard to the first arm 221 and its supports 32 also apply to the second arm 222 of the first element 60, that is to say the base 2.

[0046] In the remainder of the description, the support 32 and the foot 30 of the pumping tower will be described in relation to FIG. 4 which illustrates one of the supports 32, associated with one of the feet 30 of the pumping tower, and in relation to FIG. 5 which shows an exploded view of the support 32 and the foot 30 of the pumping tower.

[0047] In these figures, the support 32 is composed, among other things, of a support plate 321 and two fixing wings 327 for connection with the foot 30 of the pumping tower. The support plate 321 has a rectangular shape with a back 3212 facing the two fixing wings 327, and a front face 3211, opposite the back 3212. The housing 322 is formed in the support 32 from the front face 3211 of the support plate 321, in order to accommodate a pad 326. The housing 322 has a rectangular shape whose dimensions are strictly smaller than those of the support plate 321.

[0048] The housing 322 is delimited by a housing bottom 3221 against which the pad 326 is pressed, also rectangular in shape and coming into contact with a housing bottom 3221. It is then understood that the pad 326 has dimensions substantially equivalent to the dimensions of the housing 322 so that it can rest on the housing bottom 3221. The housing bottom 3221 has a thickness PI which extends between the housing bottom 3221 and the back 3212 of the support plate 321, measured along a direction perpendicular to the housing bottom 3221.

[0049] A frame 324 surrounds the housing bottom 3221, and has a thickness P2 greater than the thickness PI of the housing bottom 3221, measured along the same direction. The frame 324 is composed of a first lateral edge 3241a and a second lateral edge 3241b, together designated by the reference 3241, parallel to each other and extending in the vertical direction V of the pumping tower. The frame 324 also comprises a first longitudinal edge 3242a and a second longitudinal edge 3242b, together designated by the reference 3242, and extending perpendicular to the first lateral edge 3241a and to the second lateral edge 3241b such that they connect them together. Finally, the frame 324 has a rear face 3243, opposite the fixing wings 327. This rear face 3243 can be coplanar with the back 3212 of the support plate 321, or separate therefrom.

[0050] The frame 324 comprises at least one of the verification devices 325, for example in the form of the groove 340. The groove 340 is a clearance in the frame 324 which makes it possible to connect the housing 322 to an environment external to the housing 322, and it can be positioned on the lateral edges 3241 and / or on the longitudinal edges 3242. In the example of FIG. 4, the frame 324 comprises four grooves 340 each arranged two by two in a lateral edge 3241 of the frame 324. In the example of FIG. 5, the frame 324 comprises four grooves 340 each arranged two by two in a lateral edge 3241 of the frame 324 and four grooves 340 each arranged two by two in a longitudinal edge 3242 of the frame 324. It is nevertheless understood that the function intended by the invention is achieved as soon as a single groove exists.

[0051] At least one of the grooves 340 comprises a groove bottom 341 which is coplanar with the housing bottom 3221, that is to say that the groove bottom 341 extends in the same plane as the housing bottom 3221.

[0052] According to an embodiment not shown, the frame 324 may have only two grooves 340, each arranged on either side of a longitudinal median plane L or a vertical median plane V of the shoe 326. The vertical plane V is the plane which extends in the vertical direction V of the pumping tower, while the longitudinal plane L is the plane which perpendicularly intersects the vertical plane V.

[0053] The verification device 325 can also be the hole 350, visible in FIG. 5, made in the housing bottom 3221 of the housing 322. The hole 350 is a through hole, that is to say that it extends through the entire thickness PI of the housing bottom 3221. The verification device 325, whether in the form of the groove 340 or the hole 350, makes it possible to observe the contact between the pad 326 and the housing bottom 3221. Indeed, it has been noted that the groove 340 or the hole 350 makes it possible to ensure that no element external to the support 32 is interposed between the pad 326 and the housing bottom 3221.

[0054] The two fixing wings 327 extend parallel to each other from the back 3212 of the support plate 321. First openings 306a are provided in the fixing wings 327, allowing the support 32 to be bolted to the foot 30 of the pumping tower. The bolting is carried out by means of bolts 51 which are composed of a screw and a nut. Two brackets 329 extend between the back 3211 of the support plate 321 and each of the fixing wings 327.

[0055] The foot 30 is in the form of a hollow parallelepiped composed of four walls, including a first longitudinal wall 307a and a second longitudinal wall 307b, both extending parallel to the support plate 321 of the support 32, and a first lateral wall 308a and a second lateral wall 308b, both extending perpendicular to the two longitudinal walls 307a, 307b and in such a way that they connect them together. The foot 30 also comprises an end of contact 301, corresponding to the end fixed to the lower face 162 of the support plate 16, and a free end 304, opposite the contact end 301 in the vertical direction V of the pumping tower.

[0056] Four support fins 302 are provided from the contact end 301 of the foot 30 and are arranged in pairs, perpendicularly on each of the side walls 308a, 308b of the foot 30. The support fins 302 make it possible to increase the contact surface between the foot 30 and the lower face 162 of the base plate 16, thus making it possible to reinforce the effectiveness of the connection between the two parts.

[0057] Second openings 306b are provided through the first side wall 308a and through the second side wall 308b of the foot 30, such that these second openings 306b are opposite the first openings 306a of the fixing wings 327 of the support 32, when the latter is mounted on the foot 30 of the pumping tower. Such an arrangement of the openings 306a, 306b makes it possible to fix the support 32 to the foot 30 of the pumping tower by bolting, using the bolts 51.

[0058] Two safety elements 330 in the form of a bar and extending in the vertical direction V of the pump tower, are welded to the foot 30 of the pump tower, and more particularly to each of the side walls 308a, 308b. The two safety elements 330 are welded to the side walls 308a, 308b of the foot 30 so that the fixing wings 327 can abut against them when the support 32 is fixed to the foot 30 of the pumping tower. The safety elements 330 have the function of securing the position of the supports 32, regardless of the state of the bolting of these with the feet 30 of the pumping tower.

[0059] Figures 6 and 7 illustrate sectional views along the vertical direction V of the pumping tower, of the groove 340 according to two embodiments of the invention of the verification device 325.

[0060] In Figure 6, the pad 326 is positioned in the housing 322, against the housing bottom 3221 of the support 32. The groove 340 is formed in one of the edges of the frame 324 and it extends such that the groove bottom 341 is arranged between the housing bottom 3221 and the rear face 3243 of the frame 324. Such an arrangement of the groove 340 allows visualization of the contact between the pad 326 and the housing bottom 3221.

[0061] In Figure 7, the pad 326 is also positioned in the housing 322 against the housing bottom 3221 of the support 32. The groove 340 is formed in one of the edges of the frame 324 of the support plate 321 and it passes through the thickness P2 of the frame 324. The groove 340 thus makes visible the contact between the pad 326 and the housing bottom 3221 and also the thickness PI of the housing bottom 3221.

[0062] As mentioned previously and according to an embodiment not illustrated, the housing of the skate can be arranged on the first element, namely the base and more pre precisely on one of the free sides of the first arm and / or the second arm, i.e. the second side, the third side and / or the fourth side. In a similar manner to what has been previously described, the housing is delimited by the housing bottom and the frame. The verification device can then be at least one groove distributed on the lateral edges and / or the longitudinal edges of the frame. The groove can then comprise all of the characteristics previously described.

[0063] The front face of the support fixed to the foot of the pumping tower then corresponds to the sliding face, and its dimensions are strictly smaller than the dimensions of the pad. Such a configuration of the sliding face carried by the support allows it to slide vertically against the pad installed in the housing carried by the base.

[0064] Finally, the verification device carried by the base may be the hole provided in the housing bottom provided that it allows the contact between the pad and the housing bottom to be verified by an operator visually or via a verification tool, in particular a gauge or a mirror.

[0065] Of course, the invention is not limited to the example which has just been described and numerous adjustments can be made to this example without departing from the scope of the invention.

[0066] The invention, as just described, achieves the aim it set itself, and makes it possible to propose a device for verifying the position of the pads against their bearing surfaces. Variants not described here could be implemented without departing from the context of the invention, provided that, in accordance with the invention, they comprise a verification device conforming to the aspect of the invention.

Claims

Claims

1. Device for holding and guiding a pumping tower (1) for loading or unloading liquid gas from a liquid gas storage tank (4), comprising at least one first element (60) configured to be secured to the tank (4), at least one second element (61) configured to be secured to the pumping tower (1) and at least one pad (326) positioned between the first element (60) and the second element (61) so that it slides against the first element (60) or the second element (61), the first element (60) or the second element (61) forming a housing (322) delimited by a housing bottom (3221) and a frame (324), the pad (326) being arranged in the housing (322), characterized in that the first element (60) or the second element (61) comprises at least one device (325) for verifying the contact between the pad (326) and the housing fund (3221).

2. Device for holding and guiding a pumping tower (1) according to claim 1, in which the first element (60) comprises the housing (322) which receives the shoe (326) and the second element (61) comprises a support (32) against which the shoe (326) slides.

3. Device for holding and guiding a pumping tower (1) according to claim 1, in which the second element (61) comprises a support (32) in which the housing (322) is arranged which receives the shoe (326), the first element (60) comprising at least one sliding face (25) against which the shoe (326) slides.

4. Device for holding and guiding a pumping tower (1) according to any one of the preceding claims, in which the verification device (325) comprises at least one groove (340) provided in the frame (324) and which connects the housing (322) to an environment external to the housing (322).

5. Device for holding and guiding a pumping tower (1) according to claim 4, in which the groove (340) passes through a thickness (P2) of the frame (324).

6. Device for holding in position a pumping tower (1) according to claim 4, in which the groove (340) has a groove bottom (341) which is arranged between a rear face (3243) of the frame (324) and the housing bottom (3221).

7. Device for holding and guiding a pumping tower (1) according to preceding claim, wherein the bottom of the groove (341) is coplanar with the housing bottom (3221).

8. Device for holding and guiding a pumping tower (1) according to any one of the preceding claims, in which the verification device (325) comprises at least one through hole (350) provided in the housing bottom (3221).

9. A liquid gas storage tank (4) comprising a pumping tower (1) for loading or unloading liquid gas, a base (2) secured to a bottom wall (40) of the tank (4), the pumping tower (1) being held and guided relative to the base (2) by a holding and guiding device according to any one of the preceding claims, the base (2) comprising a first portion (20) fixed to the bottom wall (40) of the tank (4) and a second portion (22) comprising at least the first element (60).

10. Liquid natural gas transport vessel comprising at least one device for holding and guiding a pumping tower (1) according to claims 1 to 8 or at least one tank according to claim 9.

11. A system for loading or unloading liquid natural gas which combines at least one land-based means and at least one liquid natural gas transport vessel according to claim 10.

12. Method for mounting a pumping tower (1) in a tank (4) during which, in a first step, the pumping tower (1) is placed inside the tank (4), in a second step, the pumping tower (1) is held on a base (2) secured to the bottom of the tank (4) by means of a holding and guiding device according to any one of claims 1 to 8, characterized in that during a third step, the contact between the pad (326) and the housing bottom (3221) is checked.

13. A method of loading or unloading liquid natural gas from a tank (4) according to claim 9 or from a liquid natural gas transport vessel according to claim 10.

Images