Assemblywitharticulatedarmforloadingandunlo…….

1、Assembly with articulated arm for loading and unloadingproducts, in particular fluid productsBACKGROUND OF THE INVENTIONThe present invention is directed to an articulated arm for loading and unloading products, inparticular fluid products such as, for example, liquefied natural gas.More particularl

2、y it relates to a balanced loading arm equipped with a hydraulic couplingallowing a transfer to be carried out between two vessels moored side-by-side, between avessel and a platform or a floating barge moored side-by-side, or also between a jetty onwhich the loading arm is installed and a vessel mo

3、ored alongside this jetty.An example of this type of arm is described in the document GB-2 042 466. The connectionof the end of this arm to a coupling means provided on the vessel is difficult, even impossibleto carry out in difficult sea conditions. Moreover, under these conditions, the risk of imp

4、actsbetween this end and the coupling means is significant. In the majority of cases, theseimpacts lead to damage to the components constituting the end of the arm or the couplingmeans.An aim of the invention is to overcome these drawbacks. In particular it aims to allow theconnection/disconnection

5、of a loading arm to/from a vessel in difficult sea conditions.SUMMARY OF THE INVENTIONTo this end, the present invention provides an assembly for loading and unloading productswhich comprises a balanced loading and unloading arm which is installed at a first site andincludes a compass-style duct sys

6、tem, one end of which is mounted on a base and the otherend of which is provided with a connection system for connecting the compass-style ductsystem to a coupling means that is installed at a second site. In particular, the inventioncomprises a first cable which is secured between the connection sy

7、stem and a means forsubjecting the first cable to a constant tension, a connection winch which is attached to theconnection system, and a second cable which is wound upon the connection winch and isconnectable to the coupling means. In operation, the second cable is wound upon theconnection winch to

8、 thereby bring the connection system into engagement with the couplingmeans against the constant tension exerted on the connection system by the first cable andthe constant tension means.Thus, the present invention provides an answer to the requirements which have just beenmentioned. In fact, the in

9、vention allows the connection system to approach the couplingmeans installed at a site which is moving, such as a vessel, and to make a connection undergood conditions.Other characteristics and advantages of the invention will emerge from the followingdescription, given with reference to the attache

10、d drawings.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a side elevation view of a loading/unloading assembly in accordance with anembodiment according to the invention;FIG. 2 is a broken view as seen from the direction of arrow A of FIG. 1;FIG. 3 is an enlarged side elevation view of the connection s

11、ystem of the assembly of FIG. 1;FIG. 4 is a view similar to that of FIG. 3 and shows a connection system in accordance witha preferred embodiment of the invention; andFIGS. 5 to 8 are side elevation views of the assembly of FIG. 1, which show certain stages ofthe procedure for connecting the loading

12、 and unloading arm of this assembly to a couplingmeans.DETAILED DESCRIPTION OF THEPREFERRED EMBODIMENTSFIG. 1 shows a tanker numbered10 which is moored by means of amooring rope 11 to a jetty12 being situated alongside the latter. Afluid loading and unloading assembly13 according to an embodiment of

13、the invention allows the transfer, in this case of liquefied natural gas, from the tanker 10 totanks installed on the jetty12 or closeby it and connected to the fluid transfer assembly13, or vice versa.To this end, the assembly 13 comprises a loading and unloading arm 14 having acompass-style duct s

14、ystem comprising an internal tube15 andan external tube16 and carried by a compass-style support17 withtwo branches resting on a common base 18.This arm 14 is, in this case, balanced by means of a counterweight system comprising twopulleys19 and 20, connected to each other bymeans of a cable 21, and

15、 two counterweights22 and 23. Thecounterweight 22 is mounted on the pulley 20, whilst the counterweight 23 is mounted on thebranch of the compass-style structure 17 supported by the base18.A fixed duct runs along the interior of the base18 and is connectedto internal tube15 by an articulation24 comp

16、rising two 9 0bendsand two swivel joints, in this case, cryogenic and of the Chiksan? swivel joint type.An articulation25 comprising two bends and a swivel joint allows theinternal tube 15 to be connected to the external tube 16.The articulation between the branches of the compass-style support17and

17、 between this compass and the base18 is realised by means of ballbearings 26 and 27, surrounding the articulations24 and 25respectively.Hydraulic jacks, which cannot be seen in FIG. 1, allow the loading and unloading arm 14 tobe manoeuvred.A connection system 28 allows the external tube16 to be conn

18、ected toa coupling means formed by a manifold29 situated on the tanker10.This connection system 28 comprises a hydraulic coupling30 connectedby bends and swivel joints to the external tube16. The conduitsection formed by these bends and swivel joints is, moreover, provided with an emergencydisconnec

19、tion system31.The loading and unloading assembly 13 as has just been described iswell known to a person skilled in the art and will not therefore be described in greater detailhere.In accordance with the invention, a cable32 is connected at one ofits ends to a support33 firmly fixed to the connectio

20、n system28.The other end of this cable32 is connected to means34 suitable forsubjecting it to a constant tension.These means 34 comprise a double-acting hydraulic jack35 fixed, inthis case, to the jetty12 by means of a clevis mounting36. Itextends parallel to the base18.The means 34 also comprise tw

21、o sets of pulleys37 and 38, each havingtwo return pulleys around which the cable32 is wound.The set of pulleys38 is fixed by its clevis mounting to the pistonrod 39 of jack 35, whilst the clevis mounting of the pulley set 37 is fixed to the base18. Itis therefore possible to multiply the rangeof the

22、 cable 32 by eight.To apply a constant tension to the cable whatever its speed and its length over which itextends between the base18 and the support 33,the jack 35 is fed at a constant hydraulic pressure.A rod 40, fixed to support33 and provided with a ring through whichthe cable 32 passes, moreove

23、r, allows the connection system28 to bemaintained in alignment with the cable32 and a connection cable41allowing the connection system28 to be brought into the position ofconnection to the manifold29.This connection cable41 is wound on a winch 42, operating atconstant speed, which is also fixed to s

24、upport33.It should be noted, in this respect, that the greater the distance between the points ofattachment of the cables32 and 41 to theconnection system 28, the better the alignment of this system28 asregards these cables32 and 41 is. As can be seen in FIG. 1, the rod40 allows this distance to be

25、increased.Given that the cable32 is attached to the support33, the tensileload is not entirely applied to this alignment rod40. In fact, onlya lateral component is applied to this rod40 when the connectionsystem 28 is out of alignment.43 and 44, one entering the other, allow the28 to be guided when

26、this arrives close to the 29.The male section 43 is mounted on the tanker10 and extendsundermanifold 29. Its front end, to which the connection cable 41 is going to be fastened, issituated in front of the flange of manifold29.44 is traversed by the connection cable 41 and33, under the hydraulic coup

27、ling30. The free end of44, is, on its side, situated in front of thehydraulic coupling 30.Thus the possibility of impacts between the connector30 and theflange of manifold 29 is limited.Moreover, each free end of guide tube sections 43 and 44 is formed by a centring cone 45,46.Furthermore, the inter

28、nal diameter of female tube section44 isgreater than the external diameter of male tube section43, so as toavoid any risk of jamming.Once these two guide tube sections 43 and 44 are engaged in each other, the onlymovement that is still possible between the hydraulic coupling 30 and the flange of man

29、ifold29 results from the playbetween these two tubes. This movement is easily compensated for by the guide meanswhich exist on the hydraulic coupling 30.It should also be noted that a rope, which is not visible in the figures, is used to bring theconnection cable41 to the front end oftube section 43

30、, at the start of the connection procedure.During this connection procedure, the loading and unloading arm14 isput in“free wheel”by commoning the chambers of the hydraulic manoeuvring jacks of thisarm 14. Preferably, in order to limit the oscillations of the arm, a flow limiter is used on thehydraul

31、ic line extending between the two chambers of each of these jacks.Finally, a hydraulic jack of an emergency disconnection system allows the cable 32 to bedetached from support33 by withdrawing a pin 47(see FIG. 3) from a pin holder fixed to support33 and a ring at theend of cable 32.This jack is not

32、 represented in the figures as it is in alignment with pin 47.Two tube sectionsconnection systemflange of manifoldThe female sectionfixed to supportthis female sectionThe conn ecti on procedure is as follows:1) An operator firstly uses a remote con trol panel to raise theconnection system 28 above m

33、an ifold 29 (see FIG. 5). A reduced pressure can beapplied to jack 35 to avoid any slacke ning of cable 32 during this phase. Then theconnection cable41 isunwound from winch 42 and it is brought to the end of guida nee sect ion 43 bymeans of the messe nger line in order to fix it to it (see FIG. 6).

34、*2) As show n in this FIG. 6, the loadi ng arm14 is the nmano euvred into an in termediate positi on betwee n the storedstate and the connection state and the“free wheel”mode ofthis arm is actuated. 3) The cable 32 is the n activated by the applicati on of a con sta nt pressure tohydraulic jack35 (s

35、ee FIG. 7).This action is impossible if arm14 is not in“free wheel”mode. 4) The connection wi nch42 is the n actuated so as to shorte nthe len gth of unwound connection cable 41 and to allow the engagement of guidesections43 and 44 (see FIG. 1). At thesame time, the cable 32 is subjected to a con st

36、a nt tension.Thus, the closer the load ing arm14 is to manifold 29, the better itfollows the moveme nts of vessel 10 which can be see n in FIG. 5. The final alig nment iseffected before the hydraulic coupli ng30 reachesthe flange of this mani fold29.*5) As show n in FIG. 8, the hydraulic coupli ng30

37、 is the nconn ected to the flange of mani fold29 and a hydraulic limit ingvalve automatically stops the connection winch42.Before the loadi ng and uni oadi ng operati ons can start, the tension applied to cable 32 isreduced to the mi nimum n ecessary to keep the cable taut.Moreover, the emerge ncy d

38、isc onn ecti on systems are armed.The cooli ng, load ing and uni oad ing seque nces can the n start.The disc onn ecti on process follows the same logic, in a reverse seque nee.It will be appreciated that, tha nks to the load ing and uni oad ing assembly 13 according tothe invention, it is possible t

39、o carry out a conn ecti on or disc onn ecti on procedure smoothlyand in difficult sea con diti ons.Moreover, it is not n ecessary to carry out sig nifica nt modificatio ns to an existing assemblyin order to make it conform to the invention.Neither is it n ecessary to use complex means.Fin ally, the

40、connection and disc onn ecti on procedures do not depe nd on the dexterity ofthe operator and can be carried out with relatively large moveme nts.In the case of the embodime nt of FIGS. 1 to 8, the support33 and theeleme nts which are fixed to it are arran ged un der the hydraulic coupli ng 30.This support 33 is however, preferably