EP3290382A1 - Device for lifting, lowering or holding a load - Google Patents

Abstract

Disclosed is a sea state compensation device in which a load is supported via a passive compensation device and an active compensation unit, wherein a pulley is associated with a lifting device of both the passive compensation device and the active compensation unit.

Description

The invention relates to a device for lifting, lowering or holding a load according to the preamble of claim 1.

Swell or swell compensation devices (Heave Compensation System) - hereinafter also referred to as HCS - are used, for example, in offshore / marine technology when a load from a ship by means of a crane to an object supported on the seabed, for example, a platform to be discontinued. Such a task is in the assembly of rigs or offshore wind turbines before or when a drill string is lowered from a floating platform and this is raised and lowered by the sea. In research, heavy measuring devices or supply stations for robots or the like are lowered from a ship via a winch to great depths, in which case the tether, caused by the sea state, is exposed to considerable tensile loads.

To compensate for such caused by swell or swell relative movements of the load to the respective predetermined target position passive and active systems are known. In a passive system, as for example in the introduction to the description of US 4,121,806 is described, a linearly adjustable unit, for example, a hydraulic cylinder or a rotationally operated unit, for example, a hydraulic motor is acted upon in the support direction via a hydropneumatic storage unit whose pressure is designed so that the load is supported without swell in a central position - the storage unit thus acts as a kind of gas spring.

Such passive compensation systems are designed to match the particular application and the associated loads, so that an adaptation to different loads is possible only with great effort. Such passive systems are often arranged between the actual crane hook and the load and thus are located when lowering below sea level.

A problem with such passive systems is that the charging of the hydro-pneumatic storage unit must be adjusted depending on the load and the sea state and also on the immersion depth. In the US Pat. No. 7,934,561 B1 is shown a passive system with a water depth compensation, which can compensate for the effects of water depth when lowering the load something.

For applications in which a very precise guidance of the load when lowering is important, active systems are preferably used in which a linear drive, primarily a hydraulic cylinder, or a rotary drive, primarily a hydraulic motor, is designed with a position control system, through which the Last by driving the drive can always be kept at the predetermined position. Such a device with active and passive compensation device is in the US 4,121,806 described.

Such active systems are usually placed on the ship, so they must also move the weight of the crane cable, the crane blocks (pulley) and the crane hook, so that the payload is reduced by the additional weight of these components.

For larger loads, a combination of an active and passive system is usually used, as for example in the EP 1 869 282 B1 is explained.

On the one hand, the load is compensated via a passive hydro-pneumatic storage system and, on the other hand, the setpoint position of the load is kept constant via an active control system. Such a system has the advantage that over the active System only the balancing movement of the load must be effected while the actual supporting is done via the passive system. Such combination systems are particularly required when lifting a load at a predetermined speed from the seabed or from an anchored on this platform or lowered to this. A similar system is also mentioned in the beginning US 4,121,806 explained. In this arrangement, passively acting, over a hydropneumatic storage unit biased hydraulic cylinder and active hydraulic cylinders are arranged with a position control parallel to each other in a compensation unit to which the actual crane hook is attached, which is connected via the crane cable to the load.

The US 4,021,019 shows a system in which an active hydraulic cylinder is integrated into a passive hydraulic cylinder.

Such systems have a relatively complex structure and are integrated by the manufacturer in the design of the crane. Retrofitting the active system to existing cranes using only a passive compensation system is only possible with great effort, as it requires intervention in the crane structure of the existing design and also provides additional hydraulic power. In addition, existing crane designs are subject to restrictions in terms of maximum line speed, weight and diameter of the sheaves / blocks, and rigidity of the structure, so retrofitting to an active system is virtually eliminated.

In the pamphlets DE 10 2015 225 936 A1 and EP 2 896 589 A1 In each case, systems are shown in which an active compensation unit and a lifting device provided with a passive compensation device act separately on the load. Due to the separate power flow lines of the active and passive part existing systems can be retrofitted with an active compensation unit.

In these systems, the active compensation unit is each implemented with a winch arrangement, wherein a winch cable or the like acts on the load to assist the lifting device and the passive compensation device on lowering, by controlling the fibrillation of the winch cable by corresponding activation of the active winch. A disadvantage of such solutions is that a relatively large device-technical effort for the realization of the passive compensation device and the active compensation unit is required.

In contrast, the present invention seeks to provide a device that allows the compensation of relative movements with low device complexity.

This object is achieved by a device with the combination of features of claim 1.

Advantageous developments of the invention are the subject of the dependent claims.

According to the invention, the device for lifting, lowering or holding a load has a compensating device which is designed to compensate for the relative movements of the load, in particular caused by swell, with reference to a target position. The load is movable by means of a lifting device in the direction of the target position or away from it and has fixed and loose rollers, which together with a supporting cable form a pulley. The suspension cable can be caught or detended by means of an actuator to raise or lower the load. According to the invention, the lifting device is associated with a passive compensation device which at least partially supports the weight of the load L. Furthermore, an active compensation unit is provided, which can be controlled by a control unit as a function of a movement of the load caused by swell. According to the invention, the supporting cable of the pulley extends from the actuator via the rollers to an active actuator of the active compensation unit, wherein this active actuator can be controlled independently of the actuator. The pulley thus has a double function. On the one hand, it serves to move the load and also the passive compensation device on the other hand is part of the active compensation unit. Thus, the device complexity compared to the above solutions is significantly reduced at least constant function, since no separate device, such as another winch rope is required to transmit the actuating movement of the Aktivaktors on a hydraulic cylinder of the active compensation unit.

In particular, in offshore conditions, it is advantageous if the actuator and the Aktivaktor are designed as winds. Such drives are inexpensive and robust.

In a particularly preferred embodiment, a brake is provided, which is arranged in particular on a roller of the pulley to hold the carrying cable, so that there is a passive part of the supporting cable from the roller to the actuator and the other, active part of the supporting cable from the roller to Aktivaktor extends. In other words, this brake the suspension cable and thus the pulley are divided into two functionally independently operable Parten.

According to the invention it is particularly preferred if the brake acts on one of the stationary rollers, which are usually arranged on the deck (above the water level).

According to a variant of the invention, the passive compensation device has a hydraulic cylinder whose piston defines a pressure chamber effective in the direction of support, which is in operative connection with a hydropneumatic storage unit, wherein a piston rod acts on the load, so that a kind of gas spring for passive support of the load is formed ,

The bias in the pressure space determined by the pressure in the hydropneumatic storage unit is preferably selected such that the weight of the load is approximately compensated for when the piston rod is extended (in the lowering direction). In the middle position, the load is then slightly undercompensated. This causes, for example, that when the suspension cable is being activated by means of the active actuator, the piston rod holding the load extends out of its middle position in order, for example, to compensate for a lifting of a ship or floating crane due to a wave motion. Conversely, when the floating crane is lowered, the active actuator is actuated to catch up with the carrying rope so that the load remains in the predetermined target position.

The device complexity can be further reduced if the hydraulic cylinder is designed as a synchronous cylinder, wherein the active actuator associated part of the supporting cable engages the remote from the load piston rod. In this embodiment, the hydraulic cylinder is thus assigned to both the active compensation unit and the passive compensation device as an actuating element.

In a preferred embodiment of a device according to the invention, at least one loose roll of the first-mentioned part is arranged on a roller block carrying the hydraulic cylinder and at least one loose roller assigned to the active part engages the piston rod of the hydraulic cylinder facing away from the load.

The actuation of the actuators is simplified if facilities, in particular sensors for detecting the effective support rope length of Parten and the wind force are provided. Depending on the measurement signals of these devices then the actuation of the actuators by means of a control unit. Such a solution has the advantage that these devices / sensors can be provided on the cover side and it is not necessary to provide sensors for detecting the load conditions of the compensation device / compensation unit, in particular of the hydraulic cylinder below the water level.

For rapid pressure relief of effective in the direction of support pressure chamber of the hydraulic cylinder, the gas storage a bypass valve can be assigned.

• Zum einen ist ein Modus vorgesehen, in dem das "einfache" Anheben oder Absenken der Last durch Ansteuern des Aktors und Anhalten der Aktivwinde erfolgt.

The control unit mentioned above is designed to control the device according to the following modes:

• On the one hand, a mode is provided in which the "simple" lifting or lowering of the load is effected by activating the actuator and stopping the active winch.

The compensation of a relative movement of the load caused by swell or swell relative to the target position can be done by engaging the brake and driving the Aktivaktors and stopping the actuator.

In a combination mode, the load is raised or lowered while actively compensating for a relative movement of the load relative to the target position caused by swell or swell by engaging the brake and driving the actuator and the active actuator.

A preferred embodiment of a device according to the invention for lifting, lowering or holding a load will be explained below with reference to a device shown in the drawing with compensation devices to compensate for caused by sea relative movements of a load with respect to a target position.

The sole figure of the drawing shows a schematic diagram of a running with such a device according to the invention for sea state compensation (HCS) 1 ship or floating crane 2, via which a load L on another ship or the seabed 4 or a platform anchored on this is to be discontinued. The device 1 (motion compensation device, HCS) has a passive compensation device 6 and an active compensation unit 8, the concrete structure of which is explained below. On the indicated floating crane 2, a loading crane 10 is mounted, which in a conventional manner a plurality of stationary rollers (discs) 14 a, 14 b, 14 c and a plurality of movable rollers (discs) 16 a, 16 b, 16 c, which together with a Supporting cable 18 form a pulley 20. The movable rollers 16 (loose part) are mounted on a roller block 22. The fixed with an end on deck support cable 18 can be obtained by means of a winch 21 of the loading crane 10 or gefiert / discharged to the load L to raise or lower. The effective force of the winch 21 is then translated according to the pulley 20.

In the embodiment according to the figure, a hydraulic cylinder 24 is held on the roller block 22, which is designed as a synchronous cylinder. A piston 26 divides the interior of the hydraulic cylinder 24 into an effective in the direction of support pressure chamber 28 and a lowering in the direction of pressure chamber 30. The pressure chamber 28 is connected to a hydropneumatic storage unit 32, which may be formed as usual as a hydropneumatic piston accumulator with one or more downstream gas cylinders and by the pressure chamber 28 is acted upon by a biasing pressure. The pressure chamber 28 and the hydro-pneumatic storage unit 32 form a kind of gas spring. The pressure chamber 30 may be filled with a gas, for example nitrogen, and may communicate with a gas cylinder to increase the volume of gas.

As explained, the hydraulic cylinder 24 is designed as a synchronous cylinder. A load-side piston rod 34 carries the load L, which is attached to the piston rod 34, for example via a crane hook or the like. When the piston rod is extended, the force resulting from the pretensioning corresponds approximately to the weight of the load L to be moved. In the end position, this is compensated for approximately 100% in the central position of the piston 26, ie if the pressure chamber 28 is the same size as the pressure chamber 30 , there is an undercompensation.

A remote from the load L piston rod 36 of the piston 26 passes through the pressure chamber 30 and is connected via a bracket 38 with another loose / movable roller 40, which is also looped by the support cable 18. In the path of action of the pulley 20 adjacent to the other loose roller 40, two fixed rollers 42, 44 are provided on the deck side, wherein the support cable 18 passes from the fixed roller 42 to the roller 40 and from this to the roller 44, via which the support cable 18 towards a Active winch 46 is deflected.

The control of the two winches 21 and 46 by means of a control unit 48 in response to measurement signals from sensors 50, 52, on the applied force of the respective wind and the effective length of the support cable 18 or the change in length of the support cable 18 due to the Fierens or catching the suspension cable 18 is detected. As indicated in the figure, the two winches 21, 46 are then controlled via the control unit 48 in response to these signals in order to control the compensatory movements explained to compensate for the swell.

The fixed roller 42 is associated with a brake 54, via which the roller 42 and the support cable 18 can be held so that then the continuous support cable 18 in a rollers 40, 44 encircling, active part 56 and the rollers 14 a, 16 a , 14b, 16b, 14c, 16c encompassing, passive part 58 is divided. When the brake 54 is engaged, the roller 42 acts as a cover-side fixing point for the respective part 56, 58, so to speak. The active part 56 can then be caught or detained via the active winch 46 relative to the passive part, the roller 40 being able to move relative to the rollers 16a, 16b and 16c is moved vertically. Meanwhile, the passive part 58 is operated as a "normal" pulley - similar to the conventional solutions - via the winch 21. The control of the brake 54 is again via the control unit 48th

As shown in the figure, the hydraulic cylinder 24, a bypass valve 60 are assigned, via which the pressure chamber 28 can be connected to the pressure chamber 30, so that only the active compensation unit 8 is effective.

In the illustrated embodiment, the hydraulic cylinder 24 acts as an actuating element for the passive compensation device 6 and the active compensation unit 8. In principle, the console 28 can also engage a further active cylinder whose piston / piston rod then acts parallel to the hydraulic cylinder 24 on the load L.

The control unit 48 is designed so that the device 1 can be controlled at least in three modes. In a first mode, in which the load L is lowered or raised only in the direction of a target position and, for example, no sea state is present, the brake 54 is disengaged and the active wind 46 stopped / braked, so that it forms the fixed point of the support cable 18. The lifting and lowering then takes place by controlling the winch 21, in which case the rollers 14a, 14b, 14c, 42, 44 fixed rollers of a pulley and the rollers 16a, 16b, 16c and 40 form the loose roles of the pulley.

In an operating mode in which the load L is to be kept in a certain relative position at sea, the brake 54 is engaged, so that the support cable 18 or more precisely the pulley 20 is divided into the two parties 56, 58. The winch 21 is stopped. The passive compensation takes place via the gas spring formed by the storage unit 32 and the active compensation by corresponding activation of the active winch 46, via which the roller 40, the bracket 38 and the piston 26 together with the piston rods 34 and 36 by appropriate fetching or catching / Dichtholen the active part 56 of the support cable 18 is raised or lowered relative to the housing of the hydraulic cylinder 24, wherein the lowering movement is made possible substantially by the above-described under-compensating bias. The movement of the parts is indicated by a double arrow 62 in FIG.

In a third mode, the compensation of the sea state during the raising or lowering of the load L. For this mode, the brake 54 is also engaged and both winches 21, 46 so controlled via the control unit 48 that on the one hand, the lowering / lifting movement with the predetermined speed occurs and on the other hand caused by the sea state relative movements of the load L can be compensated. These relative movements are again indicated by the double arrow 62.

Since the power flow of the active compensation unit 8 and the passive compensation device 6 runs parallel in the area of the pulley and then in a common Path is transmitted to the load L via the hydraulic cylinder 24, a swing or a twisting of the load L can be avoided, as may occur, for example, in solutions in which the active compensation unit and the passive compensation device along two separate force action paths on the load L attack.

Another advantage of the described system is that all fixed rollers and all loose rollers each lie substantially in the same plane, so that the dynamic loads in the pulley 20 are minimal, since all roles are more or less burdened in the same way.

The inventive solution can be retrofitted by replacing the support cable 18 and adding the active part 56 with the rollers 42, 44, 40 in a simple manner with existing solutions.

In the embodiment, winches (winch 21, active winds 46) are used - in principle, instead of such winds and other actuators, such as linear actuators or the like can be used.

The support cable can be designed in the region of the deflection as a chain or other wear-resistant traction means. The wound up on the winding section can also be made from high-strength plastic, for example. Dyneema ^®. The stroke of the above-described active compensation unit 8 preferably corresponds only to the ship movements caused by sea state / swell (+ approx. 10 m), so that the active actuator can be designed to be relatively small.

As explained, the application of the device is not limited to the compensation of movements caused by swellings but is generally applicable where relative movements of a load due to external circumstances are to be compensated. The active compensation unit can also be designed as a mobile solution.

Disclosed is a sea state compensation device in which a load is supported via a passive compensation device and an active compensation unit, wherein a pulley is associated with a lifting device of both the passive compensation device and the active compensation unit.

LIST OF REFERENCE NUMBERS

1

Facility

2

floating crane

4

Seabed

6

passive compensation device

8th

active compensation unit

10

ladekran

14

solid role

16

loose roll

18

supporting cable

20

pulley

21

winch

22

pulley block

24

hydraulic cylinders

26

piston

28

pressure chamber

30

pressure chamber

32

hydropneumatic storage unit

34

piston rod

36

piston rod

38

console

40

loose roll

42

solid role

44

solid role

46

active winds

48

control unit

50

sensor

52

sensor

54

brake

56

active part

58

passive part

60

bypass valve

62

double arrow

Claims (10)

Device for lifting, lowering or holding a load (L) with a compensating device for compensating, in particular, rough motion of the load (L) with respect to a target position, wherein the load (L) is from a lifting device towards or away from the target position is movable and stationary and loose rollers (14, 42, 44, 16, 40), which form a pulley (20) with a support cable (18), wherein the support cable (18) can be obtained or gefiert by means of an actuator, and wherein the lifting device is associated with a passive compensation device (6) which at least partially supports the weight of the load (L), wherein an active compensation unit (8) is provided, which via a control unit (48) in response to a relative movement of the load (L ) is controllable, characterized in that the support cable (18) from the actuator (21) via the rollers (14, 42, 44, 16, 40) to an active actuator (46) of the active compensation unit (8) out is, which is independent of the actuator (21) controllable. Device according to claim 1, wherein the passive compensation device (6) as an actuator, a winch (21) and the active compensation unit (8) as an active actuator an active winch (46) and wherein a roller (42) is associated with a brake (54) via the support cable (18) can be retained such that a passive part (58) of the support cable (18) extends from the roller (42) to the winch (21) and an active part (56) of the support cable (18) from the roller (42) to the active windlass (46). Device according to claim 1 or 2, wherein the brake (54) acts on a stationary roller (42). Device according to any one of the preceding claims, wherein the passive compensation device (6) has a hydraulic cylinder (24) whose piston (26) delimits a pressure-chamber (28) acting in the direction of support, which is in operative connection with a storage unit (32), the load ( L) on a piston rod (34) of the piston (26) engages. Device according to claim 4, wherein the predetermined by the pressure in the memory unit (32) bias in the pressure chamber (28) is selected so that the weight of the load (L) when the piston rod (34) is approximately compensated. Device according to claim 4 or 5, wherein the hydraulic cylinder (24) is designed as a synchronous cylinder and the active part (56) engages the piston (36) remote from the load (L). Device according to claim 4, 5 or 6, wherein the at least the passive part (58) associated with loose rollers (16) on a hydraulic cylinder (24) carrying roller block (22) and the at least one of the active part (56) associated with loose role ( 40) acts on a piston rod (36). Device according to a preceding claim and with sensors (50, 52) for detecting the effective suspension rope length and the wind force and with a control unit (48) for controlling the actuators as a function of the detected measured values. Device according to a preceding claim and with a bypass valve (60) for pressure relief of the pressure chamber (28). Apparatus according to any preceding claim, wherein a control unit (48) is arranged to control the apparatus according to at least the following modes of operation: Raising or lowering the load (L) by activating the actuator and stopping the active actuator, - Compensation of a caused by swell or swell relative movement of the load (L) to the target position by engaging the brake (54) and driving the Aktivaktors and holding the actuator and - Lifting and lowering the load (L) and thereby compensation of a caused by swell or swell relative movement of the load (L) to the target position by engaging the brake (54) and driving the actuator and the Aktivaktors.

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