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Question New still/deioniser

4 months 1 week ago #41537 by LAJ392
Hi

Our water still which dates back to the 1960s :blink: has finally been condemned

Can anyone give advice of a good water still which we can buy or a deioniser?
Is a deioniser as good as a water still (we teach chemistry A level here)
Anyone with a deioniser - how long do you find the cartridge lasts?

any advice gratefully received!
thanks :)

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4 months 1 week ago #41538 by AndyG
Aquatron A4000 - does everything quietly, reliably and quickly but at a price.

Stuart/Bibby D4000 is supposedly our workhorse still but whilst the elements have reduced in price by 50% their quality/life seem to have also reduced at the same time. If I was buying another still it would be the Aquatron.

No idea about deionisers as last time we looked at them they cost too much in a very hard water area for the flow/capacity we required. Willing to be educated on that one ... :-)

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4 months 1 week ago - 4 months 1 week ago #41540 by TecHKnow
We bought the Elga model as in picture. The biggest waste of about £500 I have ever seen in my career. It worked well out of the box for about three months then the efficientcy of the water quality output dropped very significantly. Replacement cartridge costs about £200 and after getting a few of those over the coarse of two years, we worked out that we were getiing on avaerage six weeks lab quality water out of a cartridge before it needed to be replaced. Far too costly, Now we simply buy in a 2.5litres of pure water from TIMSTAR when we require it which seems to suit our situation
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4 months 1 week ago #41545 by woody
In theory de-ionised water is purer than distilled water but I think for use in schools distilled water is the most economic option in terms of supply but I guess it really depends on how much distilled water you use, I'm still waiting for mine to be be put back after a lab refit, it needs a 15 amp spur so any still that will happily run off a normal 13 amp socket would be my choice, don't forget when it is running you are using tying up a cold tap and sink so unless you have two in your prep room, one near a wall where the still can be mounted it needs to be in a lab close to you.

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4 months 1 week ago #41548 by AndyG
Additional plumbing for a still is simple so you don't lose the sink, however if you are installing a new plumbed device then you've got to check your local water board's interpretation of the water regs and the way your local installation conforms.
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4 months 6 days ago #41550 by Cookaburra
What I wish is that there were specialist still installers that could come and do this for you. This is the second time I have installed one and each time I have not been happy with it. This time is appears to be bumping a lot and boiling too high. I found it extremely difficult to get the element in completely level and whilst it is not actually touching the boiling vessel at the far end it is closer than I would like. It doesn't seem to be getting the waste water away as fast as it should. However the caretakers don't understand it and neither really do plumbers or electricians.

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4 months 6 days ago - 4 months 6 days ago #41551 by Baldilocks
Please don't buy a still. In these days of reducing energy (etc) they are the most expensive way of producing pure water (apart from a solar still).

Firstly, have a look at the TecHKnow wiki here:
www.techknow.org.uk/wiki/index.php?title=Reverse_osmosis
then look at the CLEAPSS advice on Reverse Osmosis (RO).

After I set mine up, I told CLEAPSS about it and Mary Owen came to see it. She then went back and set up their own which they use for everything from making tea onwards.

If that is too elaborate for you then there is an equivalent to the little Elga for about £30:
www.osmotics.co.uk/products/Refillable-D...-Polishing-Unit.html

which you can refill with loose resin at about £10:
www.osmotics.co.uk/products/1-Litre-DI-Resin.html

Whatever you get I would recommend a TDS meter such as:
www.ebay.co.uk/sch/i.html?_from=R40&_trk...w=tds+meter&_sacat=0
for about £3.50. They do NOT measure TDS (Total Dissolved Solids) because they are conductivity meters. They will react to well-known solids like CO2 and HCl, but not non-ionic substances like sugar. (they do, but only to the ionic impurities in it.)

A basic reverse osmosis system will cost you about £90:
www.osmotics.co.uk/products/4-Stage-36-G...-Osmosis-System.html

and I would recommend the arrangement that I set up in the Wiki - all of the above plus a pump and tank, so in total it should come to about £250 for a system that gives you as much good (RO) water as you want for a few quid per year, plus the DI water for as much as your resin use costs.

Ian
“Do not believe everything you read on the Internet.” -Abraham Lincoln
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4 months 6 days ago #41553 by TecHKnow
I smell a Wiki article here. Why not post that across in the area under a sutiable title.
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4 months 6 days ago #41554 by AndyG

Cookaburra wrote: This time is appears to be bumping a lot and boiling too high.


Silly question but which model - not a Bibby D4000 by any chance?

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4 months 6 days ago - 4 months 6 days ago #41555 by Cookaburra
Yes. Doesn't perform the same as the old one. Have you had problems with this model?

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4 months 5 days ago #41560 by AndyG

Cookaburra wrote: Yes. Doesn't perform the same as the old one


I had a lovely workhorse D4000 that was run nearly every day and the element blew. The £200 new one bumped a little but after some jiggery pokery it was ok. After less than a couple of years it blew again ... The £100 replacement bumped like a bumpy thing, regularly pumping hot water to waste, and I couldn't prevent it. After a short while the element failed (replaced under warranty) but the replacement was similarly bumpy. It blew again in September, was replaced and although it still bumps it's not as bad as the last couple. It seems to me that the element design is overpowered and/or has uneven power distrubution so there are hot-spots which cause local superheating. Interestingly the elements are half the price they were ... is cheap good quality?
The element in the A4S (now the A4000) is a bit longer, seems to heat much more evenly and I've replaced the element once in thirteen years ...

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4 months 5 days ago #41562 by Cookaburra
I had to replace the vessel because it cracked and the first replacement had a tiny hole in it near the constant level device which I only noticed once I had assembled the whole thing :( . At the same time I was persuaded by my colleague to order a new element even though the old one was still OK. If it is likely to be the element I might disassemble the thing and put the old one in again. If it wasn't such a trial getting it straight, Also the terminal block keeps shedding the metal clips that grip the connectors, making it very fiddly. This is why I wish there were people you could call on to just install them for you.

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4 months 5 days ago #41568 by Cookaburra
Silly question but has anyone tried anti-bumping granules in these. Anyone think it would be a bad idea?

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4 months 4 days ago #41571 by AndyG
I must admit to not having much of an issue replacing the element (freeing the old one from the scale in the neck is the difficulty). Not sure what the issue is with the terminal block - a photo would be good.

We discussed using anti-bump but the rapidity of scale build up is such that we felt it would make no difference. They would also sit on the bottom of the boiler vessel but the bump appears to be generated off the element sheath itself which is higher in the boiler.

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3 months 3 days ago #41619 by Annie
Coming into this discussion a tad late (been away in New Zealand) so might be too late.
Much depends on whether you are in a soft or hard water area as to the wisdom of getting a deioniser. I worked in a large school, ks3-5, which was in a soft water area and used an Elgacan deioniser (much the same, but considerably older as the one shown above) which was ideal for us. Opposite to what TecHKnow says but hey:laugh:
The replacement cartridges are usually in packs of 4 at under £100 and each cartridge could last about a year. I only used deionised water when necessary, the rest of the time tap water was perfectly adequate.
Apart from that Baldilocks has some great advice re the reverse osmosisB)

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3 months 2 days ago #41620 by Cookerty
We use the Elga system as pictured above but use about 6 cartridges a year. The still had to be taken out years ago as we don't have enough amps to run one! For instance if we try to boil 4 kettles at once the power trips.

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3 months 2 days ago #41622 by AndyG

Cookerty wrote: For instance if we try to boil 4 kettles at once the power trips.


That's not unusual - nowadays kettles can be 3kW each and 4 would be pulling 50A - a single ring main (a typical configuration) is only 32A.
All our labs have a self-imposed limit of three kettles for that reason - if they use 4 and the mains drops it's their fault and I don't rush.

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