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7.4 Purifiers
An Oil Purifier separates various contaminants to oil in such specific condition (Al Si, sludge, water, etc.) to maintain oil characteristics to certain limits. Oil that is fed into an engine requires controlled characteristics to maintain the engine operational reliability and extend the life usage.
7.4.1. Principle of Separation
When separation process is required, two conditions could be met:
i. to separate solid particles from a liquid, e.g. sludge / dirt from oil. ii. to separate liquids of different densities which are mutually insoluble e.g. water from oil.
a. Separation by Gravity
When liquid is filled in the tank and stored in some period of time, separation by gravity is conducted except when the liquid is emulsified.
In case of the oil, the sediments such as sludge, dirt, etc., tends to stay at the bottom, the water is in the center and the oil floats above the water inside the tank. The separation is acted due to the gravitational force from earth.
This type of separation is normally takes place in the oil settling tanks and service tanks. As the difference in their densities is very less, the separation process is very slow and is not sufficient to provide oil in a condition which can be used directly in the system.
Fig.7.4.1-1 Principle of Separation
If the shape of water particle is considered to be truly spherical, then the Separating force or the Gravitational force can be expressed as:
F= (πd3g/6) x (∂2-∂1)
Where: F = Separating Force d = diameter of the sphere of the oil and equivalent sphere of water g = 9.81 m/s2 ∂1 = density of oil in kg/m3 ∂2 = density of water in kg/m3
Note: The density of oil and water are to be taken at the separating temperature.
As evident from the above formula, the Separation force between two liquids or between liquid and solid particles is directly proportional to the Difference in their Densities. The higher is the difference, the faster will be the separation rate
b. Separation by Centrifugal Force
When centrifugal force is applied, the main separating force is equal to the difference between the centrifugal force acting on the solid and water, and the centrifugal force acting on the oil due to the difference in the density.
Fig.7.4.1-2 Separation by Centrifugal Field
As per Stokes’ law, the separating force in centrifugal separation can be expressed as:
F= (πd3v2/6r) x (∂2-∂1)
Where: d = diameter of particle v = linear velocity of particle r = radius of rotation of particle In the formula above, the separating force acting between the two liquids or liquid and solid particle is directly proportional to the difference in their densities and the square of linear velocity. This method of separation is very useful when the difference in densities of water and oil in a mixture is very less. Since the separation force is directly proportional to square of linear velocity, it can be increased many fold by rotating the container at permissible high speed.
When a centrifugal force is acting in the rotating container, all solid particles and water which is heavier than oil is displace outward from the center of rotation. The lighter liquids tend to form in the center and moves upward. Centrifugal force application increases the separation process in a rotating container.
A centrifugal purifier is essentially a container which is rotated at high speed while contaminated oil is force through, and rotates with the container. However, only material that are insoluble in the oil can be separated by centrifugal force, distillate e.g., gas oil cannot be separated from lubricating oil, nor salt can be removed from sea water by centrifugal force. Water can be separated from oil because water and oil does not form a true solution when they are mixed. Furthermore, there must be a difference in the specific gravities of the materials before they can be separated by centrifugal force.
In a centrifugal purifier, the separated water is discharged from water outlet, the oil from the clean oil outlet and the solid remain in the rotating unit. The separation by centrifugal force is further affected by the size of the particles, the viscosity of the fluids, and the time during which the materials are subjected to the centrifugal force. In general, the greater the difference in specific gravity between the substances to be separated and the lower the viscosity, in case of fuel oil the greater will be the rate of separation.
c. The Importance of Oil and Water Interface
The interface is the boundaries of layers between the separating liquid and it is important to maintain inside the bowl of the centrifugal separator to attain the effectiveness of purification. If the separator is running as purifier, it is necessary to hold the oil and water interface in the bowl within the definite range.
The position of interface is controlled by varying the outlet diameter of the heavy liquid (water) side and achieved by using gravity discs of different inside diameters.
Factors that affect the position of interface:
i. Size of Gravity disc
ii. Density or specific gravity of oil, Viscosity of oil, temperature and flow rate of oil.
In order to get possible separation result, water must never enter the disc stack.
Fig.7.4.1-3 Oil and Water Interface
Fig.7.4.1-4 Bowl Assembly
Case 1
Fig.7.4.1-5 Movement of Interface with a Change in an Input Condition (1)
Case 2
Fig.7.4.1-6 Movement of Interface with a Change in an Input Condition (2)
Factors required maintaining the position of Interface:
a. Correct size of gravity disc. b. Clean disc stack. c. Maintain the following feed condition: i. Constant oil properties i.e. Viscosity & Density ii. Constant Flow rate iii. Constant Temperature
Fig.7.4.1-7 Sensitivity of Interface Position
d. Selection of Gravity Disc
The selection of the gravity disc depends upon the following factors:
i. Specific gravity of feed oil at 15oC or at any other given temperature. Usually, the specific gravity value is given by the oil supplier and written in the receipt.
ii. Feed Rate
The adjustment of feed rate is mainly governed by daily consumption (as in fuel oil) and the effectiveness of separation/purification desired (as normally applied for lube oil). The recommended feed rate for the following:
a. For fuel oil, it is recommended that the separator should operates at about 50~70% of the rated capacity. In case that the fuel oil quality is over specification and its properties exceed NYK specifications, it is recommended to operate available purifiers in parallel operation and reduce the feed rate to about 30% for each purifier.
b. For lube oils, the recommended feed rate is the minimum possible feed rate at which separation temperature can be maintained. This minimum feed rate will help in removing the finer impurities. For a continuous separation system, it is better to circulate the full system oil through the separator 5~6 times/24 hrs rather than circulating it 10~15 times/24 hrs with increased feed rate.
The minimum feed rate is limited by the controllability of constant temperature. When the feed rate is changed drastically, it is necessary to recheck whether the gravity disc is appropriate and replacement is required, as feed rate is one of the governing factors in the selection of gravity disc.
iii. Feed Oil Temperature
The oil should be heated to obtain an appropriate reduction in viscosity and specific gravity as to effect an efficient and quick separation of water and other impurities.
However, the oil temperature should be maintained less than 100oC to avoid evaporation of the sealing water and damage to o-rings.
The treating capacity of the oil purifier depends mainly on the viscosity of feed liquid and can be plot on the Temperature-Viscosity diagram below. To ensure that the oil purifier operates efficiently, heat the feed liquid to specified temperatures as follows:
Fig.7.4.1-8 Recommended Treating Temperature
Treating temperature using a diagram:
Case 1: Purifying a heavy oil of 45mm2/sec (50oC).
Draw a dotted line (Fig.7.4.1-9 Temperature vs. Viscosity Diagram) that is parallel to the line of 40mm2/sec at 50oC and passes an intersection (point A) between a horizontal line of 45 mm2/sec and a vertical line of 50oC. From the intersection between this line and a horizontal line of 24 mm2/sec draw a line perpendicular to the horizontal axis, then read the temperature falling on the foot; that is 67oC.
Fig.7.4.1-9 Temperature vs. Viscosity Diagram
Thus the treating temperature of this heavy oil should be 67oC.
Selection of gravity disc size using nomogram:
For purifier operation, use dedicated gravity discs as per model series of each manufacturer versus the numbers of figures in which gravity disc selection nomograms are provided for reference. Select appropriate gravity discs by models and kinds of treated oil.
Never interchange gravity discs from different models as this will cause operation troubles in the purifier.
Fig.7.4.1-10 Sizes of Gravity Disc as per model (Selfjector)
ModelInside diameter of gravity disc (mm)SJ10G/GH646566.568.571.5747879 SJ20G/GH646566.568.571.57577788283 SJ30G/GH6566.568.571.57579828690 SJ50G/GH86.588.5919498103107.5113115 SJ60G/GH8688.5919498103106.5110.5115 SJ70G/GH87.5919498103107.5113119122 SJ100G/GH113116120124129136140.5142150153 SJ120G/GH113116120124129136140.5142146.5150153160SJ150G/GH114118122127134142145.5146.5153160 Example no. 1 of selection of gravity disc using the nomogram:
Case 1 - The specific gravity of treated oil at 15oC is known.
a. Treating condition:
i. Specific gravity of treated oil is 0.925 at15oC ii. Treating temperature is 70oC (Refer to Viscosity-Temperature Diagram) iii. Feed rate 3000 L/h
b. From an intersection between falling curve (line 1) of specific gravity of 0.925 and the vertical line of 70oC, draw horizontal line (line 2) to reach the vertical line of 100oC. c. Connect between the right end of line 2 and the point of 3000 L/h on the treating capacity scale using straight line 3. d. Read within which section of gravity disc inside diameter, scale the intersection made by line 3 falls. e. For this Case 1, select a gravity disc having an Inside diameter of φ79.
Fig.7.4.1-11 Selection of Gravity Disc (Nomogram)
Example no.2 of Selection Gravity Disc
Case 2 - The specific gravity of treated oil at a certain temperature is known.
a. Treating condition:
i. Specific gravity of treated oil is 0.944 at 50 oC. ii. Treating temperature is 98oC. iii. Feed rate is 1250 L/h.
b. From an intersection between rising curve (line 4) of specific gravity of 0.944 and the vertical line of 50oC (being converted to a specific gravity at 15 oC, draw curve (line 5) along the falling curve to reach the vertical line of 98oC, then draw a horizontal line to reach the vertical line of 100oC. c. Connect between the right end of the horizontal line and the point of 1250 L/h on the treating capacity scale using straight line 6. d. Read within which section of gravity disc inside diameter scale and the intersection made by line 6 falls. e. For this Case 2 select a gravity disc having an Inside diameter of φ71.5. See Fig.7.4.1-11 Selection of Gravity Disc (Nomogram).
7.4.2 Structure of Centrifugal Separator (SELFJECTOR-Genius Series)
a. Main Parts
Fig. 7.4.2-1 General Structure of Centrifugal Separator (SELFJECTOR)
The power is transmitted from the motor through the friction clutch to the horizontal shaft and is further increased in speed and transmitted to the vertical shaft through the spiral gear mounted on the horizontal shaft and pinion on the vertical shaft. The vertical shaft is supported by upper and lower bearings. The bowl mounted on the top of the vertical shaft rotates at the speed of the vertical shaft. To supply feed liquid to SELFJECTOR, the suction pump (gear pump) is connected to the horizontal shaft through the safety joint. To deliver light liquid, the centripetal pump (impeller) is built in the top of bowl. In addition, heavy liquid is forced out by a similar centripetal pump.
b. Vertical Shaft
The revolution speed of the horizontal shaft is increased by the vertical shaft pinion gear and the vertical shaft rotates the bowl mounted on its top. The vertical shaft and bowl are supported by upper springs and leaf springs radially incorporated at 6 points on the upper bearing section and lower springs in the lower bearing section so that they can stably rotate.
Fig. 7.4.2-2 Vertical Shaft Assembly
c. Horizontal Shaft
Between the motor and horizontal shaft, the friction clutch is provided. The horizontal shaft is supported by 2 ball bearings built in the bearing housing (3) and bearing housing (4). Between them, the spiral gear is mounted. The bearing housings (3) and (4) are provided with oil seals to avoid gear oil leakage. The horizontal shaft is directly coupled with the gear pump by the safety joint.
Fig. 7.4.2-3 Horizontal Shaft Assembly
d. Clutch Assembly
A friction clutch is used for gentle starting and acceleration, thereby preventing the motor from being overloaded.
Fig. 7.4.2-4 Friction Clutch Assembly
The motor shaft has a friction boss provided with a friction clutch and the horizontal shaft has a friction pulley. After starting, the motor instantly turns at critical speed, the friction clutch lining is pressed against the internal surface of the friction pulley via centrifugal force and the power is transmitted to the friction pulley (horizontal shaft side) as the friction pulley and lining slip with each other. Normally, the bowl of small size SELFJECTOR (SJ10G - SJ30G) reaches its rated speed of rotation in less than 5 minutes, and middle-size SELFJECTOR (SJ50G - SJ70G) and large-size SELFJECTOR in less than 10 minutes.
e. Brake Assembly
By springs, the brake linings are pressed against the outer surface of friction pulley to perform braking. Use the brake only when quick stop is absolutely required in emergency, for repair or checkup. For normal stoppage and not in emergency, refrain from braking and allow the rotation to stop coasting.
Fig. 7.4.2-5 Brake Assembly
f. Bowl Assembly
The bowl vessel mainly consists of body, hood and nut. The bowl incorporates separation chamber composed of disc (1) and top disc and distributor, which distributes feed liquid from the bowl inlet to the separation chamber uniformly.
There is a main cylinder, which slides vertically by water pressure to discharge sludge separated and accumulated on the inner wall of bowl during operation. At 2 points on the outer periphery of bowl, there are pilot valve assemblies for controlling the main cylinder slide.
When feed liquid introduced through the feed liquid inlet through the distributor to the separation chamber passes through the gap between discs (1), solids and water are separated and purified oil is continually delivered outside by the centripetal pump (light liquid impeller) located on the top of bowl.
Separated water is continuously discharged outside through the heavy liquid impeller.
Fig. 7.4.2-6 Bowl Assembly
g. Motor Structure
Flanged-mounted horizontal shaft totally enclosed fan cooled type (indoor type). Turning direction: Counterclockwise as viewed of load (CCW).
Fig. 7.4.2-7 Electric Motor
Fig. 7.4.2-8 Table of Motor Output, Speed of Revolution & Rated Current
The motor power is transmitted via the friction clutch to the horizontal shaft so as to mitigate the starting load. When the motor is started, it immediately reaches near the rated speed, gradually accelerating the bowl via friction clutch. During this while, the rated motor power is exceeded and, therefore, a motor enduring an overload.
Fig. 7.4.2-9 Example of Starting Characteristic Curve
Fig. 7.4.2-10 Table of Motor Overload Endurance during Starting
h. Control Panel (Model GSH-1)
The control panel is designed for automatic operation of Mitsubishi Seljector. The automatic operation processes includes the following:
i. Closes the main cylinder bowl. ii. Supplies sealing water. iii. Supplies feed oil (purifier operation) iv. Supplies replacement water. v. Opens the main cylinder bowl (discharges sludge).
Fig. 7.4.2-11 Control Panel (Model GSH-1)
The automatic control panel consists of the following:
a. Control switches, pilot lamps, fuses, power supply.
b. Control unit including timer functions.
c. Terminal unit including auxiliary relays and fuses.
The function of the control panel elements are as follows:
(1) “CONT. SOURCE LAMP”
Lights when power is supplied to the automatic control panel.
(2) “POWER SWITCH”
Turns on/off the power for the automatic control panel.
(3) “AUTO. RUNNING”
The pushbutton is a switch for starting automatic operation. The built in pilot lam will stay ON during automatic operation.
(4) “AUTO. STOP”
When this pushbutton is pressed during automatic operation, the SELFJECTOR will stop automatically after discharging sludge.
(5) “ALARM RESET”
When any alarm occurs during operation, the built in pilot lamp will come on. The type of alarm that has occurred can be known from the data display on the front panel. When the pushbutton is pressed, the sustained alarm with be reset.
(6) “DISCH. TEST”
When this pushbutton is pressed during automatic operation, the SELFJECTOR is forced to discharge sludge.
(7) “EMERG. STOP”
When this pushbutton is pressed, all the valves will immediately close, and the SELFJECTOR will stop.
(8) “MM FUNCTION SWITCH”
This selector switch is used for ON/OFF control of feed signal output from the control panel to the Multi-Monitor. When the “MM FUNCTION SWITCH” is off position, feeding signal is not outputted from the control panel to the Multi-Monitor even if the SELFJECTOR is on feeding.
(9) “OPERATION DISPLAY PANEL”
The operation display panel display input and output data, ON/OFF status of input and output signals and kind of alarm signals. Also, it is possible to enter and alter various set values on the graphic panel.
7.4.3. Procedures for Operation (Mitsubishi Selfjector Model SJG)
There are multiple types of operation that can be achieved with purifiers onboard. Basically, the piping system and separator specifications must conform to these operation procedures. It is recommended to thoroughly check your purification system onboard before attempting to operate the separators.
a. Single Purifier Operation
In normal condition, single purifier is operating at its minimum throughput. This is commonly applies to lubricating oil system for main engine or diesel generator engine.
Fig. 7.4.3-1 Purifier Single Running Operation
b. Clarifier Operation
Clarifier operation of purifiers is refers to separation of two phases or oil and (water sludge). This type of operation depends on the design of the separators and must be confirmed with the maker’s specification.
When the contamination of water sludge to fuel oil is exceeding the standard characteristic/criteria, clarifier operation is applied and when the specific gravity is too high (more than 0.99). Separation takes place into two phases only (heavy liquid and light liquid separation).
Fig. 7.4.3-2 Clarifier Operation shows the cross sectional views of the bowl of a typical G-HIDENS system SELFJECTOR (SJ-GH series) in clarifier operation.
Feed liquid is introduced from the feed liquid inlet into the separation zone by way of the distributor. While separated heavy liquid (water) and solids go to the outer periphery in the bowl, light liquid moves inside through between the discs and is discharged by means of the light liquid impeller. Some of light liquid passes outside the top disc and is returned to the feed liquid port via circulation line by means of the heavy liquid impeller. To make this take place, pressure (0.1 MPa) is built in the circulation line through back pressure valve. Upon arrival of accumulated water in the bowl at the top disc outside level, the circulation of light liquid is stopped with an ensuing drop in circulation line pressure. This pressure drop (the sign of maximum water accumulation in the bowl) is detected by a pressure sensor, a sensor output is transmitted to the Multi-Monitor and accumulated water is released from the bowl as a result. While water is normally discharged in the partial discharge mode, total discharge with sludge can take place, depending on the time spent for water detection.
Fig. 7.4.3-2 Clarifier Operation
c. Series Operation
Series operation is when two purifiers are connected, with one purifier suction is from the tank and the delivery is going to the suction line of another purifier before it is being discharged to the tank.
When the flow rate for series operation is set at the same rate as for single operation, the amount of treated fuel oil is the same, while separation efficiency is better than with single operation.
The separation efficiency of the second centrifugal separator decreases compared with that of the first centrifugal separator. The flow rate should be adjusted to match the throughput for optimum separation efficiency.
Fig. 7.4.3-3 Purifier Series Running Operation
d. Parallel Operation
Parallel operation is when two or more purifiers are employed in purification with the same suction and delivery. When the flow rate for parallel operation is set at the same rate as for single operation, the amount of treated fuel oil is double, while separation efficiency is the same as with single operation.
Fig. 7.4.3-4 Purifier Parallel Running Operation
Parallel operation is suitable for high viscosity fuel oils, as more fuel oil can be treated in the same period of time.
The operation discussed here is for SJG model of Mitsubishi Selfjector and with Automatic Control Panel Model GSH-1.
Fig. 7.4.3-5 Lube Oil Purifier Specifications
Fig. 7.4.3-6 Automatic Specification (GSH 1)
1. Equipment1SelfjectorSV2Bowl closing solenoid valve2Operating water solenoid valve unitSV3Sealing water solenoid valve3Multi-MonitorSV43-way solenoid valveV5Flow adjustment valveSV9Partial bowl opening solenoid valveV6Pressure adjustment valveCV1Feed valveV7Feed inlet valveV8Flow control valveLMLeak-MonitorV9Operating water inlet valveDDDischarge-DetectorV10Sludge discharge valveWDWater- DetectorSV1Bowl opening solenoid valve2. ConnectionsADirty oil inlet (FO: from sett. tank, LO: from sump tank)EWater inlet (0.35-0.5MPa)BPurified oil outlet (FO: to service tank, LO: to sump tank)FOperating water drainCCompressed air inlet (0.5MPa-0.9MPa)GReturn (FO: to sett. tank, LO:to sump tank)DSludge & water outlet 3. Symbols Globe valve Duplex Strainer Check Valve Pressure Gauge Cock Thermometer Needle Valve Motor Pressure Reducing Regulator Oil Line 2-way solenoid Valve Sludge and Drain line 3-way solenoid Valve Water Line 3-way Cylinder Valve Capillary line Strainer Air line Butterfly Valve Electric wiring Fig. 7.4.3-7 Automatic Specification (Piping Diagram)
a. Confirmation prior Operation
i. Make sure that appropriate gravity disc has been employed in the bowl. ii. Confirm the oil quantity in the gear case at correct level and refill if necessary. iii. Check and adjust (if necessary) air supply pressure to control equipment to 0.5~0.9 MPa. iv. Open the source valve on the operating water pipe, check the water pressure and adjust if necessary.
Fig. 7.4.3-9 Table of Operating Water Pressure
Automatic configurationDischarge modeSet pressure (Standard value)Required operating water pressureManual, GAP-11 GBC-1, GBC-2Total discharge
0.3 MPa
(3 kg f/cm2)0.35-0.5 MPa (3.5-5 kg f/cm2)GSH-1
Total discharge and
Partial discharge0.25 MPa (2.5 kg f/cm2)0.35-0.5MPa (3.5-5 kg f/cm2) v. Operate the solenoid valve manually to check the functions of operating water for opening/closing bowl is properly flowing out. vi. Disconnect the sealing water pipe and measure the quantity of sealing water and replacement water (see attached table below).
Fig. 7.4.3-10 Quantities of Replacement Water, Regulating Water (GSH-1)
Table shows the quantities of regulating water and replacement water for GSH-1 Type. On lubricating oil purifier for G-HIDENS specifications, regulating water is supplied before oil feed.
SJ10GHSJ20GHSJ30GHSJ50GHSJ70GHSJ100GHSJ150GHSJ60GHSJ120GHQuantity of Regulating Water (L/time)0.10.20.30.51.31.6Quantity of Replacement Water for Total discharge (L/time)1.31.41.94.15.210.211Quantity of Replacement Water for Partial Discharge (L/time)0.30.71.21.71.7
vii. Check the brake and make sure it is in non-braking position. viii. Make sure that the purifier has been properly assembled with bolts completely tightened. ix. Make sure that direction of rotation of motor is correct. Turn on the starter panel and start/stop the motor simultaneously within 3 seconds and check the rotation coinciding with the arrow mark in the purifier frame. x. Power on the control panel and make sure that the timer setting value is appropriate (See Fig. 7.4.3-11 Timer Counter Setting Guideline (GSH-1).
Fig. 7.4.3-11 Timer Counter Setting Guideline (GSH-1)
NOTE 1: For discharge intervals, refer to Fig.7.4.3-12 Standard Discharge Intervals.
ItemTimer No.UnitsSJ10GHSJ20GHSJ30GHSJ50GHSJ60GHSJ70GHSJ100GHSJ120GHSJ150GHInterval T000sec151515151515202020Opening Bowl T001sec3Replacement Water T002sec101114212126383837RegulatingFuel OilT003sec0waterLubricating oil112333555Bowl washingFuel OilT004sec0waterLubricating oil121319262631484847Opening bowl (partial)T011sec0.6Replacement water (partial) T012sec222336666RegulatingFuel OilT013sec0waterLubricating oil112333555Intermittent water supplyC014min15Operating water supply for closing bowlT016sec5Discharge intervalC015minNOTE 1Detection count resetC026min30Water detection setting counterC027times6Monitoring timeC022min20Bowl washingFuel OilC023times0counterLubricating oil6 Fig. 7.4.3-12 Standard Discharge Intervals for General Guidance in Processing Fuel and Lubricating Oils
Fuel oilsLubricating oilsFuel oil AFuel oil C (380mm2/s at 50oC)Cross-head engineTrunk piston engineHIDENS Operation120 min60 min120 min60 minPurifier Operation120 min60 min120 min60 min
Sludge discharge procedure is an important operation of the purifier to maintain the operational efficiency and the effectiveness of the oil separation. The inside of the bowl is being cleaned after every discharge operation in order to remove unevenly accumulated sludge and dirt.
Sludge discharge (bowl opening) and bowl closing using the operating water can be seen in Fig. 7.4.3-13 Bowl Cylinder Operation (Opening and Closing). The sludge discharge interval can be adjusted as in Fig. 7.4.3-12 Standard Discharge Intervals for General Guidance in Processing Fuel and Lubricating Oils. Fig. 7.4.3-13 Bowl Cylinder Operation (Opening and Closing)
xi. Set the power switch of the Multi-Monitor to on, and check that all the switches in the Multi-Monitor are in proper positions and necessary memory preset items/values are correctly set.
Fig. 7.4.3-14 Multi-Monitor Panel
xii. Fully open the inlet valve, outlet valve and bypass valve of the oil pipe.
xiii. Open the discharge valve at the sludge discharge outlet valve (butterfly valve).
b. Confirmation prior Operation (When the bowl has been overhauled and disassembled)
i. Make sure that the cap nut tying the bowl and vertical shaft together is tightened firmly. ii. Make sure that the alignment marks (stamp o) on the bowl meet. iii. Make sure that the bowl is fully assembled to vertical shaft; the height of the bowl is correct and easily rotated by hand. iv. Make sure that the joints and traps of the piping are firmly tightened. v. Make sure that the union and nuts of the inlet pipe are firmly tightened.
c. Start-up Operation
i. Precautions during start-up.
Fig. 7.4.3-15 Precautions
SubjectMeasuresOperation soundWhen an abnormal sound is heard, immediately stop the operation and inspect the purifier and identify the cause.VibrationVibration may temporarily occur just after start up, however, this is not an abnormality.It will be reduced when the rated number of revolution is achieved. At the rated number of revolution heavy vibration is occurred immediately stopped the operation and inspect the purifier and identify the cause. If feed liquid is being supplied, discontinue it and stop the purifier immediately without sludge discharged.Start up timeSmall, medium and large size purifiers, respectively reach their rated speed in less than 5 and 10 minutes with the current stabilized at 50 to 70% of the rated level. If the purifier fails to reach its rated speed despite the lapse of more than 10 minutes, stop it in accordance with the given stopping procedure and check the friction block. ii. Open the valves for the operating water, sealing water and oil (V5,V6,V7,V8,V9, and V10). iii. Set to on all the power switches in the control panel. iv. Depress starter switch (start button) for purifier and check the condition that all are normal. After start up, make sure that the current value of the motor falls within below 50~70% of the rating. v. Start the oil heater, make sure that the oil is recirculating and heated up to the set temperature. vi. Depress “Auto Start’ button on the automatic control panel. The following process should follow: Processes of [Opening bowl] ⇒ [replacement water] ⇒ [Discharge] ⇒ [Sealing water] ⇒[Feeding] will advance in this order.
Confirm the discharge operation by the increase of current reading or discharge sound. vii. After making sure that the purifier-run enters, regulate the by-pass valve and flow control valve V8 to a given feed rate. Check that the flow rate displayed on the Multi-Monitor is the predetermined value and the pressure at the light liquid outlet side when V6 is fully open. After the feeding, make sure that no oil leaks out in the sludge outlet side and heavy liquid outlet side viii. Throttle down the pressure valve V6 for the light liquid pressure level present in the Multi-Monitor. Then, change the MM function switch on the control panel from OFF to ON and following to set the LM alarm output switch in the Multi-Monitor to “On”. The pressure adjustment LED (green) on top of the Multi-Monitor starts flashing when the pressure is within ±15% of the set pressure, and changes to continuous lighting when it is within ±3%. ix. Adjust the circulation line pressure to 0.1MPa (1.0 kgf/cm2) through the circulation line back pressure valve V8. Set the water detector selector dial in the Multi-Monitor to working of the water detector position, and change the MM function switch on the control panel from OFF to ON. And then set the LM alarm output switch and water detection output switch in the Multi-Monitor to ON. x. Set the DD alarm output switch in the Multi-Monitor to ON. Make sure that the Rotation display LED (green) on top of the Multi-Monitor is flashing. Make sure that the Trouble display LED (red) turns off.
d. Stopping Operation
i. Depress the [AUTO.STOP] push button on the automatic control panel. The following process should follow: The feed liquid valve CV1 closes and the sequential process of [Replacement] ⇒[Discharge] ⇒ [Stop]. Confirm the discharge operation by the increase of current reading and discharge sound. ii. Stop the oil heater. iii. When the purifier has completely stopped, close all the valves and cocks (V7, V10 etc.). iv. Set power switches of the Multi-Monitor, automatic control panel and starter to OFF in that order. Make sure that power to the Multi-Monitor, automatic control panel and starter has been cut. Purifier
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