A new generation Enerpac synchronous lifting system has demonstrated its tough but tender precision lifting capabilities when deployed to delicately hoist a 600-ton racing super yacht.
Rich Rigging's EVO 12 system – which is also used for ultra-high precision industrial and construction projects – was deployed on behalf of Titan Marine in Auckland to simultaneously digitally monitor and control 14 100-ton Enerpac cylinders to stage-lift the more than $US50 million craft by 1.6 metres for repairs and maintenance.
The RACL high pressure (700 bar/10,000 psi) aluminium cylinders, operating as single units and pairs, were synchronised by one person using touch-screen PLC control from a central control point to lift the valuable craft. All cylinders were extended in synchronised steps (to within +/- 1mm tolerances) while maintaining the precious load in perfect balance.
"This is the same technology that is used in critical lifts where lives depend on its accuracy – such as precisely assembling oil production platforms or disassembling hefty and irregularly shaped mining plant," said Enerpac New Zealand Manager Neville Stuart. "Titan Marine and Rich Rigging set out to achieve the most precise and safest lift possible, while at the same time achieving the task in excellent time (2 days) and without risk to the very beautiful alloy yacht. While the sleek shape of the yacht, with its towering masts, is visually very impressive, it did pose interesting engineering issues in ensuring a perfectly balanced lift," he said.
These issues were resolved by using the EVO system, by which one PLC-controlled hydraulic power unit can be used for nine hydraulic movement functions. The integrated 9 inch touch screen HMI (Human Machine Interface) offers a user-friendly interface with logical visual system management and navigation. The hydraulic movements and cylinder positions can be monitored and controlled during the lifting procedure with visual real-time on-screen representation. The EVO System includes active and passive system securities with five warning and thirteen stop alarms.
"EVO synchronous lifting technology monitors and manages lifting, lowering, weighing, alignment and load transfer procedures of non-uniform distributed heavy loads," says Stuart. By monitoring the position and load of each lifting position – comparing it with a global datum and adjusting to the desired target position – movements are safely and efficiently managed, within permissible load and synchronous stroke tolerance parameters, pre-set to suit the project.
"As with this job, a single operator controls all movements from a central control position, which comprehensively displays the live operation and records stroke and load data for each lifting position at user-defined intervals, for client scrutiny or procedure certification.
"Besides the precision and control the system offered on the yacht lift, use of the EVO system also minimised the expense of slipway time, while achieving excellent access and holding stability for maintenance crews," said Stuart, who assisted Titan Marine and Rich Rigging crews in controlling the lift.
Further safety and ergonomic benefits were achieved by the use of Enerpac's compact but extremely powerful RACL light weight (26kg) cylinders, which were easy to place and to move around at heights. The cylinders, with 150mm strokes, are lock-nut models that provide an additional margin of safety through their mechanical locking.
EVO System functionality
The EVO system is the evolutionary result of Enerpac's 25 years of experience in specialised hydraulic engineering and lifting technology using digitally controlled hydraulics to accurately and safely lift some of the largest and most challenging structures on earth. Examples range from 1500 ton grinding mills in Western Australia to the superlifting and launch of a 43,000-ton floating oil production system in Malaysia for the Gumusut-Kakap offshore field.
The EVO hydraulic power unit (HPU) is designed as a single unit for 4, 8 or 12 lifting points and can be extended into a network with up to four units. When using 2 or more HPUs, the networked system is controlled by a separate and portable master control box.
The standard EVO System allows customers to use their existing standard Enerpac cylinders. For more complex and demanding applications the special EVO-System (EVO-W) offers additional control features for weighing systems with or without load cells.
EVO-System features and benefits:
- Multi-functional system with 9 standard hydraulic control modes: Manual, pre-load, automatic (by position or load), retract fast, depressurize, tilting, stage lifting (step-by-step), weighing and centre of gravity (CoG).
- Available to control 4, 8 or 12 points with one HPU.
- Network capability to link up to 4 hydraulic power units (HPU) to a master control.
- Interface with easy navigation and access to set-up, movement and software menus.
- Data storage and recording capabilities at user defined intervals.
- Wireless remote control.
- Variable frequency drive motor (VDFM) and Siemens PLC for very precise synchronization and control of oil flow and cylinder stroke and speed.
- For use with standard single- or double acting 700 bar cylinders.
- 3, 0 kW hydraulic power unit with 250 litres reservoir.
Advantages of digitally controlled lifting over manual control:
Safety – PLC-controlled system eliminates manual intervention with multi-operator manual control approach. The EVO System includes warnings, alarms and stop functions.
Full monitoring and control – Programmable failsafe monitoring and safety alarms. Reduces risk of structural damage by bending, twisting or tilting due to uneven weight distribution or load-shifts between lifting points. Easy-to-use and very user friendly touch screen interface displays the movement process, cylinder positions and load read-outs by lifting points and total load.
Increased productivity – less staffing required than for manually controlled lifting. One operator controls the entire lifting process while the status of every lifting point is constantly monitored and displayed. Time saving is another advantage of synchronous lifting. The process does not have to be stopped after any incremental value, checked, manually re-measured and corrected. The EVO System carries out these actions during the entire lifting process, even with low lifting or lowering speeds. Depending on the application, time savings up to 60 percent can be achieved.
Monitoring and data storage – the EVO System constantly monitors pressure and position of every lifting point for safe and accurate control of hydraulic movements. All values can be stored on a USB-stick for later use and full documentation of the process. With satisfactory progression of the procedure the EVO System provides both contractor and client with a clear indication that excessively high stresses have not occurred.
Networking - One HPU for single use controls 4, 8 or 12 lifting points. Networked up to 4 HPUs must be controlled by the separate portable master control box.