Diesel transfer.

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chrishelen

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Hi.
I need to empty a diesel fuel tank on an old barge,the only access is down the filler pipe, a depth of about 20ft.there is an access manhole in the side of the tank but i want it emptied before i get in:eek: i can borrow a rotary hand pump, the type used for 45g oil drums,i could add a length of hose to it so it reached the fuel... but would it be man enough to suck the fuel 20ft up the pipe? the owner says there is about 200gals in the tank.
thanks for any advice.
 
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chrishelen said:
Hi.
I need to empty a diesel fuel tank on an old barge,the only access is down the filler pipe, a depth of about 20ft.there is an access manhole in the side of the tank but i want it emptied before i get in:eek: i can borrow a rotary hand pump, the type used for 45g oil drums,i could add a length of hose to it so it reached the fuel... but would it be man enough to suck the fuel 20ft up the pipe? the owner says there is about 200gals in the tank.
thanks for any advice.
Click to expand...

Maximum suction lift for a pump of any sort is 25 feet. Place the pump close to the pipe and you should be OK
 
Bitter experience says it'll take a (very very) long time. Can't you get a powered pump? We use a honda water pump for pumping kerosene, and the valve seals do eventually suffer but it makes that sort of job a lot easier.
 
Davy_S said:
25Feet? why?
Click to expand...

Because a simple suction pump relies on atmospheric pressure to push the liquid into the vacuum created by the pump. The abolute max IIRC is about 30 feet. To pump against a bigger head than this requires you to put the pump at the bottom of the fluid column and push it up. 20 feet is quite a head to be working against.
 
duncan99210 said:
Because a simple suction pump relies on atmospheric pressure to push the liquid into the vacuum created by the pump. The abolute max IIRC is about 30 feet. To pump against a bigger head than this requires you to put the pump at the bottom of the fluid column and push it up. 20 feet is quite a head to be working against.
Click to expand...

I thought that it was slightly more complicated (isn't it always). Some variables are Specific Gravity of the liquid and Vapour Pressure at a given temperature.

So when suction is applied to something very dense and very volatile it will boil readily when suction is applied so can't be sucked very far up a tube. That might mean you could suck up just under 33.9' of water at ambient temp. but only 16' of something more volatile like carbon tetrachloride (heights are just a guess).

I assume that the comment regarding 25' related to diesel as it is more volatile and has a lower SG than water. I don't know the actual figures but 25' sounds reasonable. The solution is to mount the pump near the tank as mentioned. The vapour pressure won't matter then and it is just a matter of how much effort it takes to push the liquid up the pipe vs pump characteristics.
 
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It would be very difficult, and inefficient to try to "suck"fuel up 20ft. Surely, on an old barge, there will be some connections towards the base of the tank? What about the normal outlet connection? If that's not possible, how about carefully slackening the nuts on the inspection /access hatch, to establish whether the diesel is up to that level?
 
duncan99210 said:
Because a simple suction pump relies on atmospheric pressure to push the liquid into the vacuum created by the pump. The abolute max IIRC is about 30 feet. To pump against a bigger head than this requires you to put the pump at the bottom of the fluid column and push it up. 20 feet is quite a head to be working against.
Click to expand...

The distance is greater for lower-density liquids. Hence a mercury barometer is quite a neat device, not 30 feet tall! But I don't suppose diesel is much less dense than water, so 20-30 feet might be OK, if the pump is rated for that much head, and for diesel.

Mike.
 
How can it be 20' down the filler,if it's a barge fuel tank? Anyway the tank will have other fittings,if not drill a 10mm hole 1 metre above the bottom of the tank and the fuel will spurt handily into your jerry cans,but trying to suck up 20' will be heartbreaking! Good luck Jerry
 
chrishelen said:
Hi.
I need to empty a diesel fuel tank on an old barge,the only access is down the filler pipe, a depth of about 20ft.there is an access manhole in the side of the tank but i want it emptied before i get in:eek: i can borrow a rotary hand pump, the type used for 45g oil drums,i could add a length of hose to it so it reached the fuel... but would it be man enough to suck the fuel 20ft up the pipe? the owner says there is about 200gals in the tank.
thanks for any advice.
Click to expand...

200gals of what though?
 
Hi guys,
Thanks for all the replys/ideas....a bit more info. The tank is silted up.the outlet valve to the engine is blocked up solid, the drain off tap next to it is also blocked.. the manhole is level with the bottom of the tank..all are situated under the deckplates in the engine room.dont want to crack any nuts on the manhole till the tank is drained.

I should have mentioned that there are port and stbd fuel tanks connected with a balance pipe and associated valves. the sbd tank is fine.

I have a submersible pump but its too wide for the fillers 3 inch pipe.

thanks for all info, it is very helpfull.
 
chrishelen said:
Hi guys,
Thanks for all the replys/ideas....a bit more info. The tank is silted up.the outlet valve to the engine is blocked up solid, the drain off tap next to it is also blocked.. the manhole is level with the bottom of the tank..all are situated under the deckplates in the engine room.dont want to crack any nuts on the manhole till the tank is drained.

I should have mentioned that there are port and stbd fuel tanks connected with a balance pipe and associated valves. the sbd tank is fine.

I have a submersible pump but its too wide for the fillers 3 inch pipe.

thanks for all info, it is very helpfull.
Click to expand...

That all sounds fun! Can the manhole be provided with a "spout" so it can be cracked (perhaps at the top initially!) open while diesel is directed into a large bucket? 200 gallons is still a lot of buckets, so ideally it would be pumped out, presumably to some effluent tank outside the barge. But a 20 foot outlet head is still quite a challenge.

I presume that freeing up the drain with an air hose (tyre pump?) has already been tried? But it would probably just block up again unless a catheter can be introduced...

Mike.
 
mjcoon said:
That all sounds fun! Can the manhole be provided with a "spout" so it can be cracked (perhaps at the top initially!) open while diesel is directed into a large bucket? 200 gallons is still a lot of buckets, so ideally it would be pumped out, presumably to some effluent tank outside the barge. But a 20 foot outlet head is still quite a challenge.

I presume that freeing up the drain with an air hose (tyre pump?) has already been tried? But it would probably just block up again unless a catheter can be introduced...

Mike.
Click to expand...

Hi Mike, yes i thought of the catheter thing but still have the problem of what to do with the stuff when it comes out.steep flight of steps up from the ER.

so going to percy with the pump out option into 50ltr plastic drums, the idea is to filter and clean the fuel and when the tank is cleaned out pour it back in.
 
Davy_S said:
25Feet? why?
Click to expand...

Simple physics, balancing the weight of the column of liquid against atmospheric pressure. With water the theoretical maximum is 32 ft, with diesel it would be nearer 40 ft but from that you have to subtract a percentage for the vapour pressure of the liquid because your pump can't create a perfect vacuum above the liquid so 25 ft is about right. The higher the temperature the lower the max achievable lift.
 
Any chance of pressurising the tank through its breather vent and aiding your pump?

Alternatively, syphoning it off into an alongside vessel?
 
RAI said:
Any chance of pressurising the tank through its breather vent and aiding your pump?

Alternatively, syphoning it off into an alongside vessel?
Click to expand...

Not a real alternative because the syphon would have the same problems as pumping. And anyway the syphon still has to be started; by pumping? Also the free surface of the discharge vessel has to be below the fluid level in the tank which is another constraint.

Note that all pumping or syphon solutions will require a pipe which can withstand a near-vacuum inside and thus be quite heavily reinforced.

And then there's the problem of not getting pump and pipe blocked by the silt that's the root cause... challenging!

Mike.
 
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