siphons (not toilet ones)

[Fred]

Hi,

I bought a "fuel transfer siphon" from that auction site. It's 12mm tube with a squeezy black bulb in the middle. There were people selling ones by Draper and others by Laser. One seller claimed that the Draper was better than the laser but I didn't think there could be much difference between the two, so I bought the cheaper, laser, one. I was hoping to use it for odd jobs draining fluids.

I bought the one with 12mm bore because I thought that the smaller bores would have a tiny flow and take too long to be useful.

I think this one is about to go in the bin because it is useless. I bought a 25L drum of oil from costco and thought I would try the siphon to draw off 4L but in the end I gave up and poured it out. Was I being daft? Is there something I don't know about oil that prevents it from being siphoned (too viscous?) or is it just that these siphons are useless? The bulbs just don't seem to suck very well.

Is the laser one badly make or are they all just as useless as each other? I'm off to get a drill powered pump. Perhaps two: one for oil and one for aqueous use.

TIA

[Spamlet]

Get any tube you like, that isn't soluble in the fluid to be siphoned. Hold the two ends together and fill with the fluid to be siphoned. Hold your thumb over one end and stick the other into the full container (you can weigh the end down with nuts or wrap lead around,). Lower the end with your thumb over below the level of the other end into whatever you want to fill. Take your thumb off. When you have filled enough, raise the end up until the flow stops, or put a peg or clamp or cork on the end to keep the pipe full ready for the next fill. No need for any special equipment, unless you are dealing with corrosive fluids.

S

[Dave Liquorice]

Did you have it the right way round? There is a non-return valve and an arrow on the bulb (or at least mine does) to indicate which direction the flow should be. Air doesn't operate the valve very well so they can be bugger to start unless you prime it first. Once working each cycle should shift about half a mug full of fluid.

[Spamlet]

Incidentally, the last time I was far thinking enough to buy a 25L drum of oil for a motorbike said to need a particular kind, it had a blanking point for a tap.

And as a ps to a ps as it were, I have to say that in our solvent store where I used to work, apart from the 45 gallon drums - where we used an air powered pump - most solvents and oils were decanted into jugs without spilling, simply by pouring with the opening uppermost, so that it would pour smoothly without glugging. When a drum was about half empty it could then be turned around to decant the rest. Siphons tend to be rather slow, though we did have a 2" odd plastic pipe for DI water.

S

[Roger Dewhurst]

Did you have the output end below the level of the oil in the drum?

R

[Arfa Daily]

So, in fact does that mean that it is a pump, and not a siphon ? If that is what the OP has actually got, then I guess that it wouldn't work like a siphon, and that might be his problem ?

Arfa

[Dave Liquorice]

A bulb pump assisted siphon, if the outlet is lower than the inlet. They will function as a siphon as the flow will keep the NRV open.

[Andy Dingley]

Yes. You _can_ siphon oil, but not in a tube that narrow.

I've used the Draper and although it's resolutely cheaply made, it does work (used on paraffin) and it's hard to see how they could make one badly enough to stop functioning (without looking like it came out of a christmas cracker).

Machine Mart, and the one for a tenner is far better than the more common one for a fiver. Even then though, it won't be happy with oil.

[Arfa Daily]

Yeah, I can understand the bulb taking the place of your mouth doing the sucking to get it started, but what confused me was where you said

"Once working each cycle should shift about half a mug full of fluid."

Surely, once working, a siphon delivers continuous flow, until you stop it ?

Arfa

[Dave Liquorice]

The pump working as in primed. You can shift fluids up hill or between places at the same level with the pump. Not just use it to to start the siphon action. B-)

[Arfa Daily]

Ah, I see. So a sort of 'universal' siphon-cum-pump. Very useful ... :-)

Arfa

[Spamlet]

And be sure you do not unthinkingly use the drill powered one with inflammables! For those you need air power.

S

[Fred]

Why won't it like oil?

This is the one I was already thinking of:

it says suitable for motor oil and heating oil amongst other things?

[Fred]

Sorry, I should have said that I had the arrow pointing the right way. As you said, the bulb doesn't work well to prime the pipe and you can't easily submerge the pipe to prime it through the narrow opening in the top of a drum.

I think I did try using the bulb to give the flow a helping hand but hadn't thought of using it to go uphill: the outlet was definitely lower than the inlet to answer another reply.

[Andy Dingley]

Viscosity. It pumps old chipfat pretty well as it's 3/4" bore, not

1/2" like the others. However on thicker oils (tractor gearbox) it does bog down and starts to cavitate, unless you drive it rather more slowly.

[Spamlet]

You will all enjoy this:

stop now folks: this one will run and run and...

:-) S

[The Medway Handyman]

I have just purchased a 'jiggle siphon'

seen one before, but Wikipedia has an article so it must be old technology.

I want to drain toilet cisterns so it seems ideal, not tried in anger yet though.

I'll report back.

[Dave Liquorice]

Old being the operative word, we had something similar with brush on the 6' of hose for washing the car 30+ years ago. Up/down movement of the brush drew soapy water from bucket. Worked reasonably well, when priming it remember to mostly fill the pipe before bring the end down below the inlet level. The jiggles probably won't produce enough flow to stop air bubbling up the outlet side and thus preventing the formation of the siphon action.

[Fred]

Thanks for the explanations. I'll keep it for draining radiators and toilet cisterns then!