SUBSEA TECHNOLOGY
F
or submarine cable laying, maintaining tension in the cable within required tolerances is critical during the laying process to minimise the risk of cable damage due to cable cores being crushed or the minimum bend radius being exceeded. To regulate this tension, specialist machines are used to handle the cable as it is laid. One such machine is the 45Te 4-Track Tensioner made by MAATS Tech, which features electro-mechanical screw jacks for the positioning of the lower tracks. Tis precision machine is designed to
perform bi-direction cable lay and recovery operations using four tracked drives that can handle cable up to 460mm in diameter, at speeds of up to 1,200m/hr and apply a cable tension of up to 45Te. Te four drive tracks are arranged in 450 diagonal opposing pairs and engage with 4.94m of cable that passes between the tracks. Each track is individually driven and can be individually positioned for a precise grip and tension. Te four points of contact in the four-track tensioner give a more even grip around the cable circumference.
THE BENEFITS OF SCREW JACKS Te upper tracks are actuated by hydraulic cylinders and the lower tracks are positioned by electro-mechanical screw jacks. Te use of screw jacks on the lower tracks gives this MAATS tensioner the advantage of more accurate positioning for better tension control compared to hydraulic only systems. Te screw jacks that position the two
lower tracks consist of four sets of jacking system pairs, with one jacking system installed at each end of the lower tracks. Each system is a pair of screw jacks mechanically connected and driven by an electric motor with speed and position feedback coming from an absolute encoder. With one motor
EMT0500 screw jacks
S SPECIALIST
revolution equal to 0.06mm linear movement, the system can provide some very accurate positioning. By using pairs of screw jacks the track is supported on each side for an even load distribution over the structure. Te screw jacks used are variants of
Power Jacks’ precision 500kN E-Series Machine Screw Jack (type EMT0500) that have been specially adapted for the tensioner. Within each screw jack system one screw jack has an integrated geared motor drive and the other an absolute encoder. Te electric motor includes an integral brake to guarantee the screw jacks can be locked in position in addition to the jacking systems being naturally self-locking. Te ability to self-lock is a feature screw jacks can offer so that position can be maintained
52
www.engineerlive.com MAATS 45Te tensioner
even when there is no power. Te screw jacks are mounted
UBSEA SOLUTION
How smart screw jacks asisst in maintaining the tension in subsea cable laying
on pivoting points with a trunnion mount at the screw jacks gearbox and a clevis end on the lifting screw. Teir design is marine-rated and fully certified and approved by DNV (Det Norske Veritas), a process that included load and operational testing. Troughout the project Power Jacks’ team of specialist engineers worked closely with MAATS to ensure the best design was provided on schedule. Managing director of MAATS Tech,
Lisa Edwards, says: “Our projects require timely delivery and great flexibility when it comes to schedules. Power Jacks has always accommodated all our requirements for timely delivery and we regard it as a trusted supplier.” Managing director of Power Jacks, Keith
Mackie adds: “Tis is an interesting marine application for our screw jacks that once again demonstrated how our expert team of engineers can work closely with a client to deliver the best solution.” Te MAATS 45Te Tensioners are in
service on cable laying vessels (CLV) such as the state-of-the-art ABB vessel, the CLV Victoria. l
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60
