SOFT LANDING CYLINDEREAB ENGINEERING

Impact dampers for installation of structures subsea.

The EAB Soft Landing Cylinder is an impact damper helping to reduce the impact load when landing structures subsea. The Soft Landing Cylinder also secures that the final touchdown speed is not exceeded in case of failure of the heave compensation system.

PRODUCTION DESCRIPTION

The EAB Soft landing Cylinder is using seawater as working medium and damping is achieved by throttling sea water through a pattern of holes in the cylinder wall. The cylinder fills up automatically with seawater when submerged and does not need to be connected to any external system, hydraulics or accumulators. The system can be used at any depth without pre-adjustment.

Through the special throttle pattern developed and sized for each application, the damping force is maintained relatively constant over the stroke and large dynamic peaks are avoided. Typical peak retardation values are 0.5 to 1.0 G.

The cylinder has full response to heave motions (close to 1G) achieved by the unique patented piston design allowing for high flow at low resistance through the piston when the piston is moving down. No springs are used, and it does not represent any danger to personnel, compared to spring loaded cylinders.

The most common applications are for running tools and smaller modules designed for a landing velocity typically 1.8 m/s - and larger modules weighing up to 2400Te designed for a typical landing velocity of 0.5 m/s. The cylinders are designed to withstand lateral loads caused by angular offset and/or friction from sliding.

Full sealing to pressure when the piston is moving upwards

The piston is short circuiting when stroking out, and piston and rod fall down and follow the heave motion (patented)

MAIN SPECIFICATIONS

Initial lowering velocity: up to 0,5 m/s (typical)*Velocity end damping: down to 0.02 m/s **Deceleration: Typical: 0,5 – 1,0 GDamping travel length: 200 mmLowering travel length: 70 mmResponse to heave motions: Close to 1GWater depth: No limitDesign life: Based on material selection• Carbon Steel Top side outdoor: preserved for 1 year Submerged: Single installation (unlimited landing attempts)• Duplex Top side outdoor: Unlimited Submerged: 20 years

* higher velocities is possible (to be determined by detailed calculations in each case)** limited by minimum hole size achievable

TECHNICAL INFORMATION

The EAB Soft Landing Cylinder comes in a range of standard sizes and configurations.

Soft Landing Cylinder options:• Cylinder models from SL70 to SL500• Top flange or bottom flange mounting• With/without Canisters (2 ea.)• Threaded/clearance holes in the flange• Cylinder housing material: Carbon Steel or

Duplex• 270 mm stroke

MOUNTING Select between top flange or bottom flange mounting

CANISTERCanisters can be mounted to cylinder housing to keep the unit water filled during topside testing/air usage.

MATERIALSFor repeated use, cylinders with Duplex housing is recommended. For single installations, cylinders with carbon steel housing is the most cost efficient option.

CYLINDER OPTIONS

SELECTION OF CYLINDER

Selection of the appropriate cylinder size for a given application is based on:• Location of CoG (symmetrically related to the cylinders)• Landing speed• Steel mass• Added mass (drag)• Trapped water• Angular offset (tilting) (EAB default: 2,5°)• Friction coefficient between piston rod and base structure

(EAB default: 0,2)• No. off cylinder to be used (max. 4 off recommended)

Diagram 1 and 2 can be used for selecting the appropriate cylinder size based on a landing speed of 0,5 m/s and default values for angular offset and friction.

Note: the cylinder size selected will always be verified by EAB before any PO is accepted.

SMALL SERIES, SL90-SL230

Diagram 1: Cylinder selection based on a landing speed of 0,5 m/s, steel mass and added mass (small series).

-50

0

50

100

150

200

250

300

350

400

450

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125

Adde

d m

ass

(T)

Steel mass in air (T)

Selection of cylinder size Steel mass vs added mass at 0,5m/s landing speed

SL70

SL90

SL115

SL140

SL180

SL230

SL70

How to use the diagramThe lines in the diagram represents the capacity limit for a given cylinder size. When combining the steel- and added mass for a given application the appropriate cylinder size is given by the first line found to the right. Example: 40Te steel mass/150Te added mass -> SL180

0

200

400

600

800

1000

1200

1400

1600

50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 525 550 575 600 625 650

Adde

d m

ass

(T)

Steel mass in air (T)

Selection of cylinder size Steel mass vs added mass at 0,5m/s landing speed

SL280

SL340

SL420

SL500

Diagram 2: Cylinder selection based on given landing speed and steel mass (large series).

LARGE SERIES, SL280 - SL500

DIMENSIONS – TOP FLANGE, 270MM STROKE

DIMENSIONS – TOP FLANGE

DIMENSIONS – BOTTOM FLANGE, 270MM STROKE

DIMENSIONS – BOTTOM FLANGE

SL70 SL90 SL115 SL140 Sl180 SL230 SL280 SL340 SL420 SL500A 210 250 300 350 420 470 560 670 800 930B 470 480 480 485 500 520 540 555 595 605C 270 270 270 270 270 270 270 270 270 270D 64 84 109 134 174 224 270 330 410 490E 25 30 30 35 40 50 60 70 80 90G 6x17,5 6x22 8x22 8x27 8x33 8x33 8x33 8x39 12x39 12x39G (thread) 6xM16 6xM20 8xM20 8xM24 8xM30 8xM30 8xM30 8xM36 12xM36 12xM36H 170 200 240 280 340 400 470 580 700 840I 110 140 175 200 250 310 370 470 600 700J 136 169 186 228 282 329 396 463 565 668 26 42 58 84 146 222 315 549 860 1240Weight,

(kg)

SL70 SL90 SL115 SL140 Sl180 SL230 SL280 SL340 SL420 SL500A 225 270 290 335 430 470 540 610 800 930B 475 480 480 480 500 510 520 535 585 595C 270 270 270 270 270 270 270 270 270 270D 64 84 109 134 174 224 270 330 410 490E 20 25 30 35 40 50 50 60 75 75G 8x17,5 8x22 12x22 12x27 12x33 16x33 16x33 24x33 24x45 24x45G (thread) 8xM16 8xM20 12xM20 12xM24 12xM30 16xM30 16xM30 24xM30 24xM42 24xM42 H 180 220 240 280 360 400 470 540 680 820I 110 140 175 200 250 310 370 470 600 700J 136 169 186 228 282 329 396 463 565 668 27 43 59 78 146 216 288 478 845 1200Weight,

(kg)

Cylinders top flange Cylinders bottom flange

The following materials and coating are standard

MATERIALS AND SURFACE TREATMENT

ORDER FORM

Part Material CoatingCylinder housing MDS Y 05/Y 07 (Carbon Steel)

MDS D 41/D 45 (Duplex)

Outside: NORSOK M-501 system 7bInside: XYLAN 1424Outside: NORSOK M-501 system 7b

Cylinder Rod As above Xylan 1424Bearings Orkot 380Bucket Polyurethane (PUR)

Code Description Options Commentxx Cylinder size 70, 90, 115, 140, 180, 230,

280, 340, 420, 500mm Material CS, D CS: Carbon steel

D: 22 Cr. Duplexff Flange TF, BF TF: Top Flange

BF: Bottom Flanget Flange hole T, C T: Threaded hole

C: Clearence hole b Bucket 1, 0 1: With Bucket

0: Without Bucket

Customer specific version of the EAB Soft landing Cylinder can also be supplied. Please contact EAB for information.

SLxx – yyy – mm – ff – t – b - ts

EAB Engineering ASStudieveien 16N-2815 Gjøvik

NorwayPhone: +47 61 18 41 40

E-mail: sales@eabeng.nowww.eabeng.no