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2.0 GENERAL DESCRIPTION OF THE INSTALLATION

2.1 System description (design/operation)

2.1.1 DESCRIPTION OF HYDRAULIC SYSTEM

The hydraulic system is built as a central hydraulic mainring line system in openloop where hydraulic pumps deliver oil to a main pressure line. From this mainpressure line a number of hydraulic motors can be run provided that a sufficientnumber of power packs have been started. In order not to overspeed the hydraulicmotors, a speed control valve is installed up streamof each motor.

The main hydraulic pumps are of axial piston type, swash plate design with variabledisplacement. The pump displacement (swivel angle) is hydraulically controlled via

the pressure regulator on each pump.

At start-up, the variable pump is in max. swivel angle, and a pressure is built up inthe pressure line. This pressure is internally bled off through the pressure regulatorand a solenoid valve, energised at start-up, causing that the swivel angle is reducedto min. After approximately 10 seconds the solenoid valve is de-energised, and pilotoil from the pump will push the swash plate to an increased swivel angle, and oil isdelivered into the main pressure line. However, if no oil is needed, a pressure isbuilt up in the main pressure line. When this pressure reach the set pressure of theproportional valve, the valve will open for oil through the pressure regulator, and theswivel angle will decrease until a balance is reached between oil delivery and oilconsumption.

If the oil consumption from the cargo pumps is increased, the system pressure willdrop slightly, and the oil flow through the proportional valve will drop. Pilot oil fromthe pump will now push the swash plate to increased swivel angle until a newbalance is reached between oil delivery and consumption.

By this system the oil delivery from the hydraulic pumps will always be the same asthe oil consumption from the motors.

All cargo and other pumps connected to the system may be remotely controlledfrom Framo control panel, vessel computer or locally at each pump via the speed

control valve STC (Speed Torque Controller). This valve is designed to control thedischarge from cargo- and other pumps powered by a central hydraulic ring linesystem.

The valve is set to a maximum oil flow, limiting the oil flow to the hydraulic motorand thus limiting the motor speed and consequently prevents overspeed. The oilflow is proportional to the speed, which can be steplessly regulated.For further information about the STC-valve, see separate instruction.

The portable pump speed is locally controlled at the pump.

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The main filter and the oil cooler with a built-in temperature controlled shut-off valvefor the cooling water, are installed in the main return line to keep the oil clean and

the temperature within desired range. The shut-off valve is installed by the Yard onthe cooling water inlet line, but controlled from the FM system control system.

For safe operation of the system, several transmitters/switches/alarms are installed.

2.1.2 HYDRAULIC FLUIDS, FLUID CLEANLINESS

Hydraulic pumps, motors and controls are devices requiring close tolerances,controlled wear surfaces, accurate finish and an adequate supply of clean hydraulicfluid. Contaminated fluid will not provide proper lubrication and is a leadingcontributor to reduced efficiency, excessive downtime and increased maintenance

cost.

Max. recommended water contentis 300 PPM (0.03 %), and must under nocircumstances be above 500 PPM (0.05 %). If in doubt, please contact Framo.

Recommended cleanliness levelis code 16/12 according to ISO 4406(or CETOP PR20). 16/12 means that number of particles:Above 5 micron in 100 ml is between 32000 and 64000.Above 15 micron in 100 ml is between 2000 and 4000.

For further information, see separate instruction.

2.1.3 CARGO HEATING SYSTEM

Refer to dedicated system drawings and separate instruction.

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2.2 System description (electrical)

2.2.1 GENERAL

The Framo cargo pumping system is controlled by a Programmable Logic Control(PLC) installed inside the control panel. The PLC is programmed by Framo andprovides the logic for safe operation of the system. Modifications of thesystem/program carried out by others may effect the warranty of the system.

This section should be read in conjunction with dedicated system drawings.

2.2.2 ALARM SYSTEM

The alarms are divided into two groups:

a) Alarms and shut down of the hydraulic system.b) Alarms for indication (pre-warning) only.

All alarm inputs, except "excessive wear" are normally closed. This means that thesystem is built up on normally closed contacts. Hence if a contact opens or there isa loose wire, an alarm condition occurs, i.e. FAIL TO SAFE.

Each alarm is indicated with a flickering light and an acoustic signal until the"acknowledge" push button is activated. If the alarm condition still is on, the lampwill turn into a steady light and buzzer will stop

To clear group a) alarms, the "system reset" button must be activated before anypower pack can be restarted.Group b) alarms have got automatic reset.Please refer instrument list for applicable alarms and time delay.

2.2.3 MAIN POWER PACKS

Start/stop of the main power packs is performed manually from control panel, orfrom the electric starter cabinet.

The power packs can be started in any sequence. Maximum 4 starts should bemade during an hour. Maximum 2 following starts can be made, then 15 minutes

between each. The starts are controlled by the PLC, including eventual starts fromthe local starter cabinet. The hydraulic pump will be disengaged for 10 secondsduring start-up. The limit switches on the suction line for each power pack will stopor prevent start of the corresponding power pack only. An alarm light is provided foreach power pack to indicate closed valve.

If more than one power pack is loaded and the hydraulic oil temperature increases

to 65C or above, the control system will automatically unload all power packs insequence except for one. The running light will start flashing for the unloaded powerpacks, and the high oil temperature alarm is re-initiated each time a new powerpack is unloaded. The power packs will automatically be reloaded in sequence

when the hydraulic oil temperature has decreased below 60C.

Note! If the system is in thrusters mode, the power packs will not be

unloaded.

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2.2.4 SYSTEM PRESSURE CONTROL

System pressure is set by means of the potentiometer in front of the control panel,

as a voltage input to the proportional valve driver card. This input is amplified by theproportional valve driver card to approximately 100 mA at minimum systempressure and approximately 400 mA at maximum system pressure. The setpressure is automatically set to zero until one of the power packs has been loaded.

2.2.5 REMOTE CONTROL OF HYDRAULICALLY DRIVEN PUMPS

The command signals from potentiometers in front of the control panel are feddirectly into the proportional valves for speed control. The built in pressuretransmitters give a 4-20 mA (0-300 bar) feedback signal to the instruments on thecontrol panel.

2.2.6 COOLING WATER VALVE

The valve is automatically controlled and will receive "open" command at hydraulicoil temperature above 50C. It will stay open until the temperature decreases tobelow 30C when "close" command is given.

"Close" signal will also be given when the temperature is below 49C after the lastpower pack is stopped.

If no power packs are running and the hydraulic oil temperature is below 50C, buthigher than 30C, the cooling water valve will close.

If there is a mismatch between command- and feedback signal, an alarm will bereleased after 1 minute. If a failure in the temperature monitoring loop occurs, openvalve command is given.

2.2.7 SYSTEM SHUT DOWN

Please refer to instrument list for applicable shut down functions.If a shut down function is initiated, the PLC will give shut down command to the

power packs in sequence. The first power pack stops immediately. The delaybetween shut down command of each power pack is 0.75 seconds.

2.2.8 MANUAL OVERRIDE OPERATION

Please refer to section 5.

2.2.9 TROUBLE SHOOTING

Please refer to section 6.

2.2.10 INERT GAS PRESSURE LOW

Input from external system, handled as:

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- group b) Alarm in addition to shut down of cargo pumps

2.2.11 ELECTRIC CONTROLLED BALLAST PUMP EJECTOR

The ejector for the priming system is automatically controlled by the PLC. The PLCreceives input from a combined high- and low level switch installed in the pumpcasing and engages/disengages the solenoid valve for ejector pilot air control. Theejector is started when low level is detected, and stopped at high level. Time delayfor start and stop is 2 seconds. The logic contains interlock to prevent starting theejector when no power packs are running and operators pressure command is lessthan 30 bar.

2.2.12 INTERFACE TO VESSEL CONTROL SYSTEM

The Framo cargo pumping system can be operated/monitored from Framo controlpanel or remotely from vessel control system (VCS). Mode is selected in front of theFramo control panel. Available control and monitoring signals are indicated ondedicated system drawings.

2.2.13 INTERFACE TO POWER MANAGEMENT SYSTEM (PMS)

A start request signal is sent from Framo system to PMS. Start is prohibited until a'power available' signal is received from PMS. For detailed arrangement, refer todedicated system drawings.