alfa laval centrifuge mba 104

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kenjh
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alfa laval centrifuge mba 104

Postby kenjh » Sat Apr 02, 2011 5:58 pm

HI ,I have an older unit and not getting a lot of help from the manufacturer ..what is the flow of water needed to maintain the water seal on this rig?at what pressure ? does the oil NEED to be heated ? is it bad to run the flow slower to get cleaner output...is it normally gravity fed or should it be under pressure..and how much ?? I will be cleaning #2 diesel in 2000 to 4000 lt lot's ...it is a home based unit to feed my tug ...thank's Ken P..and I am not an engineer,,,I'm a truck driver with a old boat...all 30 feet of steel..

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The Dieselduck
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Re: alfa laval centrifuge mba 104

Postby The Dieselduck » Sun Apr 03, 2011 5:14 pm

Hello Ken, welcome to the forum. Hopefully I can provide some further information to get you comfortable running this unit. The unit is still pretty common, and yes Alfa Laval is not the best for customer support for smaller clients.

You asked... "what is the flow of water needed to maintain the water seal on this rig?" I assume you know how to make the seal in the first place, so the short answer is that once its made, your good to go. Although its not a bad idea to check it.Constant running of the seal water cause allot of waste water and its associates cost.

"at what pressure ?" You should have a back pressure in the unit, I forget exactly, but its something like 2 bar. But basically, if you are in no rush to process your fuel batches, run the output flow as slow as possible by restricting the output valve not the input (you don't want to damage the pump by starving it).

"does the oil NEED to be heated ?" Heat for this diesel grade is not necessary, although I see in the literature, that Alfa Laval recommends it. But in my experience heat is only necessary for less viscous grades, like your Grade 5 or 6.

"is it bad to run the flow slower to get cleaner output..." No. See above for controlling flow

"is it normally gravity fed or should it be under pressure..and how much ??" As long as your unit is not too worn, it should be able suck from a tank below its level, but obviously, a slight head would be best.

"I will be cleaning #2 diesel in 2000 to 4000 lt lot's" the grade is not an issue here, and the lot is not a issue either, depending on the quality of the fuel to begin, this initial fuel quality will be your only limiting factor, vis a vis necessary manual cleaning. This cleaning interval will be determined by what you find when you clean it.

You can download a small guide on cleaning these units from the main site, in the machinery section; it also contains some helpful general information as well. you can find it http://www.dieselduck.ca/machine/04%20a ... arator.pdf

Hope that's helps,
Martin Leduc
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Re: alfa laval centrifuge mba 104

Postby kenjh » Sun Apr 10, 2011 7:33 am

HI ..and thank's for all the info..I tend to take my time as I learn new things..I am building some of the tools for working on my unit..and trying to adapt plumbing on the pump with cam locks and check valves for simple use when I get everything working..and I have a healthy respect for high speed tools...so I tend to go slower then destroy things ..a comment on here about oil levels got my attention ..and saved me grief ..I checked the sight glass and it was stained looking like it had oil..I am useing synthetic engine oil right now ..still learning the right grade ..in the middle of trying to get my Harbor tug up and running..and in the water..soon I hope...thanks again..

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Re: alfa laval centrifuge mba 104

Postby kenjh » Wed Apr 13, 2011 6:40 am

nothing goes as the manual shows....my unit has a bottom feed for the water seal..the dirty oil supply pivot on the lid was frozen causing the pipe connections to flex...not seeing it in operation or having someone to show me how it works slows down the learning curve ..but the pictures you have helped alot ..getting ready to start feeding it water and oil and see what happens next..I can drive a 100.000 pound rig through city traffic swing a 15 speed gearbox or a 5 and 4 with out clutching ..and back a 60 foot rig into a blind ally way...but turning on a 9,000 rpm spinning monster still gets my respect..so water first ..with a slow output ..then oil to the feed pump ..and restrict the out put for the clean oil..should it start clean from the start ?? or should it purge some dirty oil at the first?? for how long?? ..will the sound change with the oil going through?? I don't have a water seal alarm ..what should I watch for?? should the oil supply start wide open and control just the output??...If I don't know I ask..thank's Ken P

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Re: alfa laval centrifuge mba 104

Postby The Dieselduck » Thu Apr 14, 2011 6:00 pm

seal bottom feed... im confused, perhaps you could post a pic, and see this bad boy.

I would recommend you clean the unit before you start up. No need for purging if she is up to speed and your water seal is made. There should be no real noticeable noise, sometimes some machines will be noisy if throughput is too high, so just keep minimum flow you should be good. There;s nothing to fear its not rocket science, well, not really.

No need for alarms, just keep an eye on your sight glasses to see whats going on - one is a case drain should be empty otherwise you have a bad oring. Water output sightglass, should be very minimum flow if any depending on feed stock - mostly water the unit is working / fuel=not so good, oring damaged. output sightglass, should have clean diesel splashing in it but not too much - as low as you can handle (timewise / needs). Input full open, as previously mentioned, throughput controlled by closing in on output, creating some back pressure - that's ok.

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Re: alfa laval centrifuge mba 104

Postby BilgeRat1 » Sat May 14, 2011 7:09 pm

When you start feeding oil at first after cleaning, you will see some water in the water sight glass for a short while as the feed oil displaces some of the seal water, but that should not last too long.

As for lube oil, you might be better off with a good quality HP gear oil. This is a worm driving a worm wheel and the gears are pretty highly loaded. I had good results with a heavy MobilGear (can't remember the number right offhand, same thing we used in Falk gearboxes); the gears showed very little wear after long running. We also fitted a magnet to the gearcase drain plug; there was always a bit of oily powder to wipe away when we changed the oil every six weeks.

I have a routine service & cleaning manual I made up for these to help my assistants learn the basics, if you would like a copy (It's a Word document), I'd be happy to email one to you. Let me know if you'd like one.
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Big Pete
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Re: alfa laval centrifuge mba 104

Postby Big Pete » Sat Jun 18, 2011 12:28 pm

Hi,
I have just read this thread and I have a few thoughts, not sure if all the previous advice is clear, and if you have no previous experince with a purifier then you want to be 100% sure!!!.
If you open the bowl all the parts have locating dowels or cut outs and they must be correctly lined up on assembly. When tightening the locking ring (big round nut) that clamps the two halves of the bowl together, you should always use a "soft" hammer with a lead head to avoid damaging the bearings. The Nut has to be exactly aligned with the bowl. Both have an 0 with a line through it stamped on them and they should line up exactly when the lock ring is correctly tightened.
Because of the high speed of rotation, each bowl is factory assembled and then balanced. Consequently, if any component is changed the complete bowl has to be re-balanced for safety. If the bowl is out of balance then there can be excessive vibration, bearing failure and even disintegration of the purifier, with shrapnel flying everywhere.
If you have one bearing fail, change all the bearings on the horizonatal shaft and the vertical shaft. The vibration from the first bearing to fail is transmitted through the gears to all the other bearings and damages them. If you only replace the obviously damaged bearing you will be opening up the purifier every 10 days to change one bearing each time. Much better to change all the bearings and have no problems for a couple of years.
First thing I was always taught was after re-assembling the purifier, always turn the bowl by hand and get it spinning at a good speed then close the top cover fully for a few seconds before opening it and checking that the bowl is still turning, (just in case the bowl height is adjusted incorrectly and the bowl is touching the top cover) If the bowl has stopped, you have to investigate.
If this purifier was previously used to purify the same grade of fuel it SHOULD have the right gravity disc inside, but check with the NONOGRAM in the instruction manual just in case, if you have the wrong size disc, you will either dump good oil into your sludge tank or be pumping dirt and water into your clean oil tank.
With regard to lubrication you require a good gear oil, some purifier makers reccommend coating the gears with Molybdenum Disulphide grease, in addition to filling the sump with oil, when running in new gears. The instruction manual will give you suitable grades. Synthetic oil is better for purifiers operating at high temperatures but mineral oil is fine purifying cold diesel oil.
The general set up should be that you put your dirty oil into a "settling tank" and allow the water and dirt to settle to the bottom for a few days after it is delivered/transferred into this tank.
Then drain the sedimenbt from the tank through a drain valve at the bottom.
Next open all the oil valves from the settling tank through to the clean or service tank, except for the lever operated valve between the purifierer pump and the service tank, this should be left shut for the moment.
This type of purifier is fitted with a relief valve that allows oil to recirculate from the pump discharge back to the pump suction, so that the oil flow through the purifier can be regulated by the lever operated valve, while maintaining full flow through the positive displacement gear pump.
Next step is to light the blue touch paper and stand well back ...... (metaphorically of course)
Start the motor, if there is an ammeter for the motor it should go straight to maximum for a few moments, then fall back to maybe one tenth of the scale. The motor clutch should be slipping to reduce the load on the motor. Feel the purifier for vibration and listen for noise, if you have any, shut down the purifier and investigate.
If you have the instruction manual it wil telll you how to check that you have the correct RPM by counting the turns on the revs indicator and using a stopwatch. (If it is slow, check the hand brake is off and that the centrifugal clutch pads are in good condition.)
Once the purifier is running at the correct revs, minimum current and without any vibration or excessive noise, you can put on the water seal. You should hear a slight reduction in noise when the clutch stops slipping.
Open the water filling line on top of the purifier and you will see the water flowing through the sight glass into the bowl, let the water flow until it starts to overflow the bowl and run out of the sludge discharge at the bottom of the purifier. Close the water valve. Adding the water should also slightly damp out the noise. If you are purifying cold oil there is no need to add water continuously.
However, if you are purifying Heavy Fuel oil at 98 C or Lube oil at 95 C the water seal will evaporate and you have to top it up regularly. In SOME SPECIAL cases you leave a slight drip of sealing water into the purifier to water wash the oil, i.e. any solids that are more soluble in water than in oil will be discharged out of the sludge discharge with the excess water.
Once the bowl is full of water it will slightly damp the vibration and noise.
Finally you can slowly open the flow control lever on the pump discharge bowl inlet until you have the desired flow rate. The slower the oil flow, the longer the DWELL TIME in the purifier and the more dirt and water you will remove, especially smaller particles and those with a density close to that of the oil. The oil should displace some of the water out of the bowl, down the sludge chute but then the
If you do not have an alarm for low back pressure you can leave the discharge valve fully open.
If a pressure switch is fitted, you must first adjust it so that it will go into alarm when the discharge valve is fully open, then shut in the discharge valve until the alarm is cleared.

When you stop the purifier, you should first close the flow regulating valve, then stop the motor and put the hand brake on. The handbrake is to stop the purifier vibrating and damaging the bearings while the bowl slows down. (The bowl is usually dynamically balanced while running at constant speed, but can be unbalanced during accleration/deceleration, depending on the distribution of sludge. The brakes stops the bowl more quickly and because of it's spring loaded contact with the bowl acts as a damper.
The bowl should always be cleaned before starting the purifier because some of the sludge can become dislodged from the sides of the bowl and put the bowl out of balance.

All the best with the purifier, let us know how it goes.

BP.
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Re: alfa laval centrifuge mba 104

Postby kenjh » Fri Jun 24, 2011 6:19 pm

this is what I am looking for,,with starting the little bomb,,which is what I call it..out of respect,,i have not used the break's and only done dry runs so far..and now I understand that is not a good thing..for the bearings..it now has gear oil in it..cam-lock connectors and a open tank for holding the oil as I learn how it all works..so far no bad noises ..I have a new heavier power cord with a twist lock plug . and a water supply pump setup for testing,,this is going slow .mostly because work get's in the way of learning ,thank's to both of you for your help..I will let you know how thing go....on a side note..how would this work for separating an oil spill ?? would it remove all the oil from salt water skimmed through this machine ??/

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Re: alfa laval centrifuge mba 104

Postby Big Pete » Sat Jun 25, 2011 11:42 am

Hi Kenjh,
Glad the information is helpful.
Purifiers are only designed to remove small % of water from oil.
If you want to remove a small percentages of oil from water ( bilges, oil spills) you want an oily water seperator.

Many years ago (1987) I sailed as 2E on a ship called the Irving Canada, the Super was always complaining to the Chief about the high Main Engine L.O. consumption and eventually the ship's Engineers bowed to the pressure and made a little Modification.
The L.O. sludge tank, below the purifier, was above the Double bottom. The procedure adopted was to drain the water out of the sludge tank and then purify the remaining sludge back into the main engine sump.
No obvious problems until a new 3rd Engineer arrived who decided it wasn't necessary to drain the water out of the sludge tank first, because " the purifier would take the water out anyway".......
I went down the engine room for standby, and while checking around found all the oil in the Main Engine sump was completely emulsified.
Quick phone call, "Chief we have a problem", sailing cancelled and all the deck & engine room crew manually cleaning the L.O. drain tank/sump and the crankcase for 48 hours.
We were able to transfer all the oil to the renovating tank and tried to purify the oil while we cleaned. Unfortunatly, the suction pipe was a foot above the oil level, even with a full charge of oil + water in it.
No chance of welding in there so I had to weld up an extension suction pipe to reach the bottom of the tank, fixed in place with a tapered spigot and Devcon.
By the time we had cleaned everything the oil was looking good again and we batch purified it down to the sump, just to make sure.

The Chief swore that he would never purify the sludge tank back into the sump, but after more pressure from the Super about the oil consumption he folded and started doing it again.


On the ship I have just come off, the engineers were transferring the scavenge drainss and under piston drains into the L.O. renovating/settling tank and then purifying them back into the sump. Same story, Super complaining about L.O. consumption and cost of sludge disposal costs, so the enginerrs took the the line of least resistance.

It didn't help that the L.O. purifier had the wrong gravity disc in it, was running at the wrong temperature and with an excessive oil flow rate, the operating water line for bowl closing was also choked with scale, once those problems were fixed the L.O. consumption went back to normal anyway.
B.P.
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Re: alfa laval centrifuge mba 104

Postby JollyJack » Sun Jun 26, 2011 6:58 am

I have found that water can be removed from crankcase lub oil quite effectively. I joined a ship, relieving a Russian Chief, and found the ER bilges full of water, up to the after crankcase oil seal, the flywheel was under water for half of it's diameter! (B&W 6MC60 (Long story, to be related under a swinging lamp!) Lip seals keep oil in the crankcase, they don't keep water going from engine room bilges to the crankcase!

The Super, who, I believe, sailed as a Junior with Noah on the Arc, increased the oil inlet temperature to the purifier from 83 to 120C......and the water just poured out of the sludge discharge! We did that for 48 hours and ended up with lub oil as clean as a whistle! It IS possible to teach old dogs new tricks.
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Re: alfa laval centrifuge mba 104

Postby Big Pete » Sun Jun 26, 2011 12:57 pm

Hi Jolly Jack,

That must have been a while ago!!
All the purifier makers have recommended 95 C at the purifier inlet for L.O except for crosshead engines when they recommend 90 C for a long time.
I assume at 120 C most of the water would have boiled into steam!

BP
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Re: alfa laval centrifuge mba 104

Postby JK » Sun Jun 26, 2011 4:38 pm

So Big Pete, you were on the Canada, does that mean you made it into the ice?

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Re: alfa laval centrifuge mba 104

Postby JollyJack » Sun Jun 26, 2011 5:20 pm

it was in '99, just before I retired and came to be employed by the Government. The water came out as water, at a very high flow rate. Back pressure on the puri outlet was in the region of 2 bar, so I'd imagine that kept it liquid. It must have flashed off as soon as it went down the sludge discharge though.

I was in the Ocean, sistership of the Canada, that would be around '92ish
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Big Pete
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Re: alfa laval centrifuge mba 104

Postby Big Pete » Mon Jun 27, 2011 1:22 pm

Yeah, JK,

Came back from my Honeymoon to find that my previous employers (Hays Ships UK) had all five of their Survey / ROV Ships laid up in Leith because of lack of work in the North Sea. They told me stay at home on the dole until they found work for the ships then they would call me. Needless to say I was straight down to a manning Agency, and flew out to Canada to join the Canada few days later. My wife kept getting calls asking me to rejoin my previous ship, because they couldn't find a Chief with Diesel Electric, DP & ROV support experience!! They obviously didn't believe I could find another job so quickly.
There was a spat between the UK and Canada at the time and the Canadians wouldn't recognise my Extra Chiefs or Chiefs tickets,only my Seconds so I ended up sailing as Second.
We made it into the ice, once spent over 24 hours cleaning ice out of the sea boxes non stop. They had put a SW recirc line in so that hot water from the cooler outlets recirculated back to the pump suction, thermostatically controlled by a pneumatically operated 3 way valve. If they had put it to recirc back into the Sea box it would have melted the ice. Unfortunatly they didn't. It got so bad that to keep up with the ice we floated the ice out of the strainers by taking the covers off then cracking the valve open. Anyway we kept the lights on and the engine running at the speed the Bridge required.
After the one trip on board the Canada, I got a job as Chief again in the North Sea, close to home.

Jolly Jack,
Its a small world.
That would explain it, 2 bar back pressure would push the oil/ water interface well into the purifier and stop the water evaporating.
I joined a Norwegian owned Panamax OBO the "ACINA", as Chief Engineer a few years laters and found the renovating tank full of MELO emulsified with 20% water content. They had had problems with the Piston Cooling telescopics and had done a full oil change on the main engine. All the engineers had been doing was to drain a few litres out of the bottom of the renovating tank every day and hope that a miracle would happen and it would seperate out on its own.
I told the Second to put steam heating on the tanks to break down the emulsion but he didn't believe it would work. Eventually I bet a month of my pay against a month each of the Engineers & Electricians pay that after 24 hours at 90 C, clean water would run out of the bottom of the tank leaving good oil behind. If I had lost I would haveworked for 4 months for nothing but I won. We sent off a sample for analysis and it came back as perfect. I was worried that some of the additives would have been washed out, but apparently not. I let the Engineers off the bet, but they kept me well supplied with beer for the rest of the trip.
The company complained because when we had seperated the the oil out we only had 20,000 litres of useable oil. I had to do the maths for them and explain that if you have an emulsion containing 20% water and you remove the water you are only going to have 80% of the original quantity left as good oil.

Heat will break down emulsions almost every time, unless there are emulsifying chemicals such as detergents present.

BP
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Re: alfa laval centrifuge mba 104

Postby JK » Mon Jun 27, 2011 3:50 pm

LOL Big Pete, we used to take the strainer covers off and shovel the slush into the bilges and every hour someone would take a swing by the vent to shovel the slush away so it wouldn't freeze and airlock the seabays. On another ship our seabay vent went through the bulwarks and shoot the slush out 20 feet as it vented, but you had to check it as well because it would freeze and block. I'd be there in the middle of the night, hanging over the side with a 7" steel bar beating at it, thinking, if I go over, they would miss me when??
I used to love icebreaking.
I used to burn 25% water content waste oil in our exhaust boiler. The second didn't think it could be done, but jack the pressure high enough for a good flame and it will burn.


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