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This leaflet has been based on authentic material by Alfa-Laval andcompleted with the invaluable help of Mr Fotis Avdellis , Mr Giannis Giannosand Mr Stephanos Kotronakis.We thank them a lot. Eleni Mamali ©, CostasChandrinos©

5th Semester, Text #1

Viscosity Controller

Warm up: What does a viscosity controller do?

Now read the text about the Viscosity Controller and answer the questions.

1. Safety Instructions

1.1 Key Factors for Safe Operation

The viscosity system is designed and supplied for a specific function (type of liquid,temperature, density, etc.). The system must be used for this function only, andstrictly within the manufacturer´s specifications.

For safe operation, strictly follow the instructions for installation, operation andmaintenance in this manual.

The following is compulsory for safe operation:

1. Never ignore alarms. Always eliminate the cause before resuming operation.

2. Ensure that personnel are fully trained and competent in installation,operation, maintenance, and emergency procedures.

3. Use only genuine spare parts.

Question: Mark the following questions as T or F.

1. __ Any type of liquid, density , temperature etc is appropriate for theoperation of the particular viscosity controller.

2. __ You can install, operate and maintain the viscosity controlleraccording to your estimation.

3. __ General knowledge about viscosity controllers is adequate for anengineer.

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2. System Description

2.1 System OverviewThe Viscochief MkII system is specifically designed for installation and operation in fuel oilconditioning systems to automatically monitor and control fuel oil viscosity

The basic Viscochief MkII system comprises of:

•A viscosity sensor

•A control unit

•A temperature sensor.

Question: Roughly describe the route of oil through the V.C. system. Now write the question after answering it in oral:

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2.3 FunctionThe EVT20 viscosity sensor continuously measures the viscosity of the fuel oil being fed tothe engine. This measurement is compared with a set value stored in the EPC 50V controlunit. The control unit then regulates the heater to raise or lower the fuel oil temperature tomaintain the required oil viscosity.

Vital process parameters are monitored and displayed and an alarm indication is given whenparameters are exceeded.

Question: What is the use of the control unit?

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3.1 EPC50VThe EPC 50V control unit is positioned close to the sensor (less than 5 m). The operatorspanel is mounted in the cabinet and/or in a remote position, for example in the control room.

General principle for changing control parametersThe ‘Enter’ button is used to:

–enter into a parameter list

–enter into a parameter

–accept/store a new parameter value.

The ‘+’ or the ‘–’ buttons are used to change the value flashing in the display window.

Process parameters

Set the process parameters to suit the installation as follows:

1. Push ‘ENTER’ to access the parameter list.

2. Push the ‘+’ button go through the list. The display shows a describing text, and avalue alternately.

3. Set the desired parameters.

4. When the parameters have been set, ‘End’ (flashing) shows. Push ‘+’ and’ -’simultaneously to return to normal operation.

For more information on parameter setting and how to change the factory set parameters; seethe parameter list booklet.

NOTEFactory and Process parameters only can be changed when the EPC control is started.This is indicated by the green LED next to the start button. Installation parameters canonly be changed when the system is in stop mode.

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3.1.1 Controller information

Process information is available from the EPC50V controller.

LED display information•Equipment in operation: LED green.

•Activated valve: LED green.

•Ramp activated (temperature or change-over valve): LED flashing green.

•Heater blocked (by no oil flow or high temperature alarm): LED flashing green.

•Active alarm: LED flashing red.

•Acknowledged alarm: LED red.

Alpha numeric displayDuring normal operation the measured temperature and viscosity are shown

alternately on the display.

All alarms are indicated in the alpha numeric display. For further information see theAlarms and Fault Finding chapter.

3.1.2 More operational information may be read as required, by pressing the ‘+’ button repeatedly.

To return to normal display continue pressing the ‘+’ button, or by pressing ‘+’ and ‘-’buttons simultaneously.

The following is an example of the information available in the instantaneous valueslist. The actual values displayed depend on equipment installed, automation leveland parameter settings.

Oil temperature

•Oil viscosity1)

•Heater regulating valve position (optional equipment)

•Electric Heater power (additional equipment)

•Change-over valve. Gradual change-over shown in percent on display (electricchange-over valve). (optional equipment)

1) The viscosity at 50 °C is, ‘V50’, is also displayed in the list when changing from DO to HFO or vice versa.

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PROCESS INFORMATION

The information is arranged in 2 lists; Run, and Viscosity.

Question: Fill in the gaps with the appropriate form of the following verbs.

1. depend 2. contact 3. purchase 4. upgrade

NOTE: The information that is specifically available on each installation will a. __upon the level of automation that has been b.___. To c._____ to a higher level ofautomation with more process information, please d.____ your local Alfa Laval office.

Process Information

1. Press the ‘PROCESS INFO’ button on the operator panel.

2. Push ‘+’ to see the different lists. The following lists are available: Run list,Viscosity list, Timer list.

3. Press enter button to see the information.

Step through the values with the ‘+’ button.

Question: match the underlined words above with the synonyms bellow.

____________ catalogue ___________ figures

____________ procedure ___________ at hand, handy

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Run listRun time for the individual components (hours)

3.2 Normal Operation3.2.1 Before Start

The following procedures assume the system pipework and valvearrangement is set for operation with open valves and pipework secure, andthat commissioning action described in the Installation instruction book has

been successfully performed.

Question: Which three steps should we have taken before starting theV.C.(viscosity controller)?

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3.2.2 Start

3.2.3 Stop - complete shut down

By stopping the system as follows, no alarm will be activated.

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3.3 Oil Operating Modes

In connection with bunkering, it may be necessary to adjust some of the parametersettings. This is certainly the case when changing to an HFO that is a much differentgrade. Some of the following parameters may have to be changed:

•Density parameter Pr 23. If changing to an oil of a different density, change thedensity parameter in order to obtain the most accurate viscosity measurement.

•HFO temperature setpoint parameter Pr 30. The new oil must be heated to adifferent temperature (as this temperature set point is used for the end of thetemperature start ramp) to obtain the same viscosity setpoint.

•Temperature Pr 32.

Question: What should we do after bunkering HFO of much different

grade?

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3.3.1 Heating Function from OFF to DO

When the control unit is switched ON to DO mode (for temperature control), the fueloil temperature and viscosity are monitored and displayed.

The heating start sequence is controlled by Fa 31, temperature start ramp, whichallows the oil to be heated to the set temperature within a set time. (If Fa 31 = 0, theramp function is inhibited, and the control unit regulates directly using normal setpoints, alarm limits etc.). The TT LED flashes during ramp function.

When the fuel oil temperature is within 3 °C of the set temperature, the start ramp isstopped and normal temperature control is initiated. The TT LED changes to steadyshine.

•Low viscosity and low temperature alarms are disabled during start ramp.

•At the beginning of the start ramp, a maximum time is set for start ramp duration toensure that it does not run for too long time. An alarm is activated if the start rampexceeds maximum time. See the “Alarms and Fault Finding” chapter.

5.4 Display Alarms and Actions

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5.4 Display Alarms and Actions

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5.5 Alarm Tests

Almost all alarms must be tested with the EPC running. In some cases, the EPCmust be in AUTO mode.

NOTE

If any parameter value is changed to activate an alarm, do not forget to reset tothe original value before operation

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Question: After reading the Alarm chart write three sentences for each of the three types of conditional.

1st

2nd

3rd

3.3.2 Heating Function from OFF to HFO, or DO to HFO

To change from DO to HFO

When the control unit is switched ON to HFO, or switched from DO to HFO, the fueloil temperature and viscosity are monitored and displayed. The start sequence is

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controlled by Fa 30, temperature start ramp, which allows the oil to be heated to theset temperature within a set time. The VT LED flashes during ramp function; the TTLED shines steadily if change-over from DO to HFO has been made, but does notshine if change-over from OFF to HFO has been made. (If Fa 30 = 0, the rampfunction is inhibited, and the control unit regulates directly using normal set points,alarm limits etc.)

On change-over from DO to HFO, heating of the oil begins when the controllerdetects an increase in viscosity, indicating that Heavy Fuel Oil is entering the system.

Heating is paused if the controller detects a decrease in viscosity during the startramp.

When the temperature has reached 3 °C below the temperature set value of HFO,the control unit automatically switches to viscosity control. When the TT LEDswitches off and the VT LED shines steadily, the start sequence is complete andviscosity control attained.

•Low viscosity and low temperature alarms are disabled during start ramp.

•At the beginning of the start ramp, a max. time is set for start ramp duration toensure that it does not run for too long. An alarm is activated if the start ramp runs tomax. time.

•When changing over for DO to HFO and vice versa the viscosity at 50 °C isdisplayed in the Instantaneous values list. This makes it possible to see how muchDO to HFO is in the system at the usual reference temperature of 50 °C.

Question: Find 6-7 examples of verbs in the passive voice. What tense are they in?

3.3.3 HFO Control Heating Mode

HFO control type

The HFO control type (temperature or viscosity), is set in parameter Pr 19. Theselected type is shown by the sensor LED’s on the display.

If the viscosity sensor (VT) LED is lit, the unit is in viscosity control.

If the temperature sensor (TT) LED is lit, the unit is in temperature control.

3.3.4 ____________________________ (Question: Give a title to the passage)

When a change is made from HFO to DO, the control unit continues to control thefuel oil viscosity. The viscosity value is maintained by decreasing the temperature ofthe HFO-DO blend. The TT LED is flashing and the VT LED shines steadily.

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When the temperature reaches the DO set value, the control is automaticallyswitched over to DO mode (temperature control). The TT LED then changes tosteady shine, and the VT LED switches off.

3.3.5 Automatic change-over – HFO/DO

Heater fault

In the event of a heater fault it is possible to arrange for a controlled change over toDO.

The automatic change over valve has to be installed; then by using parameter Fa14the system can be set to automatically change over to DO in the event of a heaterfault.

It is recommended to set Fa14 to a lower value than the low temperature alarm limit.When the set low temperature limit is reached, the change-over countdown timer (2minutes) starts. The DO LED next to the DO/HFO change-over button starts flashing,and a text appears intermittently showing the time to change-over. The change-overcountdown timer can be aborted by pressing the DO/HFO pushbutton.

3.3.6 DO to HFO to DO valve time

When the electric change-over valve is installed the new fuel can be introduced intothe system gradually by regulating the time it takes for the change-over valve tochange from DO to HFO, or HFO to DO. Although this will be strongly influenced bythe level in the respective HFO and DO service tanks.

See parameter Fa12 and Fa13.

3.4 Manual Operation

These functions are provided in the unlikely event that the EPC50V is not working.They enable components within the system to be operated independently, directsupervision by the operator will be required.

3.4.1 Manual operation of parts of the system

Heating

Heating can be controlled by the EPC50V (if applicable). Pressing the start button onthe EPC will start the heating.

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There is also a hand lever under the cover of the valve actuator.

For electric heating the fixed loads within the power unit can be switched on stepwise, in up to 5 steps (depends how big the heater is as to the number of elementsand the number of steps).

HFO/DO change over valve

The HFO/DO change over valve can be manoeuvred with the hand lever. (It will benecessary to change Fa12 to disable the change over valve from the EPC, if the EPCis still ON)

3.5 Automatic start up after power failure

The Viscochief MkII can be set to be automatically restarted after a power failure,and if an alarm should be activated or not, with a software parameter; see theparameter list.

When the electric power returns after the power failure, the heater is restarted again(after a set delay time) with one second intervals.

3.6 Regular checks on the system

Regularly check the process values to note any unusual changes.

If SRV position (or instantaneous electric heater power in the case of electric heater)changes dramatically, this could be an indication of heater clogging, provided otherprocess criteria remain the same.

When the outside ambient temperature is high, regularly check the internal controlpanel temperature (see parameter list Pr7). This should be max. 70 °C.

3.7 Control and monitoring levels

The Viscosity system is prepared for 3 different levels of control. The levels are:

1. Local / Remote

2. Additional remote operators panel

3. Fieldbus

It is important that you firstly identify which level of automation is installed (also seethe Installation System Reference manual).

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3.7.1 Local / Remote

Operation is dependant on the functions installed by the automation supplier.

Possible remote features - standard outputs

•Common alarm

•High temperature / low viscosity

•High viscosity / low temperature

•Fuel mode - DO/HFO

Possible remote features - optional outputs

•4 -20 mA, 2 analogue outputs:

–Viscosity

–Temperature

–Position indication of regulating valve

–Electric heater output

3.7.2 Additional remote operators panel

It exists a possibility to install an additional operators panel in a remote position, forinstance in the control room. This means that all functions available in the localoperators panel will be available in a remote installation. There are two variantsavailable;

•EPC50 remote operators panel, unit (for wall mounting)

•EPC50 remote operators panel (for panel mounting)

Question: Describe the steps for changing the modes of operation.

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3.7.3 Fieldbus

Profibus or Modbus board shall be installed

When the remote control is via a fieldbus from the central automation system,operation is as per the automation system makers instructions.

6.2.6 Pipework