Hot water heater.

[TonyDuell]

I assumed it was just 2 metal electrodes (connected to the mains) dipping into the water. There would be enough current flow to heat the water I think. That would agree with the 'no elements' comment.

As I said I saw a steam iron that worked like that, although you did add a little common salt to the water.

I believe this is termed an 'electrode boiler', there's a wikipedia entry here :

https://en.wikipedia.org/wiki/Electrode_boiler

[turretslug]

I have to admit that I was slightly surprised to find that the expensive new electric shower (this is some 30 years ago, mind) that my parents had fitted at their house had a heater that comprised a drilled transparent perspex block with a naked resistive spring in the water flow, mains being connected by the brass machine screws that retained each end of the spring and sealing by rubber washers on the outside of the perspex. Water was fed in and out of the block by a loop of rubber hose wound around the inside of the casing (evidently to increase the resistance of the path to input metallic pipe and output wet human....) A rather insignificant label reminded the installer to connect the neutral to the outlet end of the element and that the unit was unsuitable for use in areas of less than a certain water resistivity. The whole idea terrified me, but after using it a couple of times on trembling tip-toe, I gave up worrying. Ignorance is bliss and all that.

[Tractorfan]

Hi,
This thread reminds me of seeing ads for 'electrode boilers' in old magazines, catalogues, etc. Some of them were big three phase jobs designed for schools, hotels and the like.
Are they still used at all? Or have they now been outlawed?
Cheers, Pete.

[Lloyd 1985]

I would have thought such boilers would trip RCD's so would be fairly useless in modern installations.

Water and electricity in the same box is a silly idea...

Regards,
Lloyd

[Radio Wrangler]

Originally Posted by turretslug

.......that comprised a drilled transparent perspex block with a naked resistive spring in the water flow, mains being connected by the brass machine screws that retained each end of the spring and sealing by rubber washers on the outside of the perspex. .....

That's exactly what I found in one at my parents!

When I re-did my house, in went a new hot water cylinder. I'll stick to trad plumbing for the bathroom.

David

[BulgingCap]

It was very common practice in the impoverished conscripted Russian Army a few years back (and maybe still is) to use bare electrodes in buckets to boil water. The buckets were not always plastic either !
It reminds me of often working through the summer in Russia when the district heating plant would be shut down from April to October. In many cities this supplied not only the apartments but also schools and hotels. I hated washing in cold water before and after work so I visited the local market and came back with a bag full of giant 'boiling sticks'. I wired 3 in parallel and attached a length of the best mains lead that I could buy. I think they were 1.5kW each. The best quality mains plug was obtained and the pins bent and primped. I removed the mains socket in the hotel bathroom and put more tension on the receptacles. I found that if I filled the bath to a greater depth than the electrodes' coils and switched on, the water was piping hot after about 40 mins (time to eat breakfast) and cold could be added to preference. I made a set for my mechanical colleague and gave him strict instructions: Fill bath, put in electrodes and secure, insert plug, switch on. To test temp- under no circumstances put hand in water. Switch off socket, remove plug, test water. If not hot enough switch on for longer. When satisfied- switch off socket, remove plug, remove electrodes from bath, hide them in suitcase so room girl will not find them.
This worked a treat for many weeks. We were working with two Swiss guys who we did not get on with so we kept a secret. Every morning as my colleague and I stood outside looking all pink and scrubbed the Swiss would appear all grey and unkempt looking.
One morning I was just getting in the bath when all the lights went out with a bang. My colleague had pulled the elements out of the water without switching them off. He was stark naked at the time. The shrapnel wounds were extensive and not pretty.
He had thrown the busted coils in the waste bin, and the next day a notice appeared pinned to the door in the corridor about not using electrical appliances in the rooms. It was in wonderful Rusglish.
BC

[Oliver35]

Originally Posted by Dai Corner

The Scotsman you have in mind is probably Big Clive who describes them as 'suicide showers'
https://youtu.be/cNjA0aee07k

That's him! He does a fine line in lethal water heaters of various types..

Oliver

[skodajag]

Originally Posted by BulgingCap

It was very common practice in the impoverished conscripted Russian Army a few years back (and maybe still is) to use bare electrodes in buckets to boil water. The buckets were not always plastic either !
It reminds me of often working through the summer in Russia when the district heating plant would be shut down from April to October. In many cities this supplied not only the apartments but also schools and hotels. I hated washing in cold water before and after work so I visited the local market and came back with a bag full of giant 'boiling sticks'. I wired 3 in parallel and attached a length of the best mains lead that I could buy. I think they were 1.5kW each. The best quality mains plug was obtained and the pins bent and primped. I removed the mains socket in the hotel bathroom and put more tension on the receptacles. I found that if I filled the bath to a greater depth than the electrodes' coils and switched on, the water was piping hot after about 40 mins (time to eat breakfast) and cold could be added to preference. I made a set for my mechanical colleague and gave him strict instructions: Fill bath, put in electrodes and secure, insert plug, switch on. To test temp- under no circumstances put hand in water. Switch off socket, remove plug, test water. If not hot enough switch on for longer. When satisfied- switch off socket, remove plug, remove electrodes from bath, hide them in suitcase so room girl will not find them.
This worked a treat for many weeks. We were working with two Swiss guys who we did not get on with so we kept a secret. Every morning as my colleague and I stood outside looking all pink and scrubbed the Swiss would appear all grey and unkempt looking.
One morning I was just getting in the bath when all the lights went out with a bang. My colleague had pulled the elements out of the water without switching them off. He was stark naked at the time. The shrapnel wounds were extensive and not pretty.
He had thrown the busted coils in the waste bin, and the next day a notice appeared pinned to the door in the corridor about not using electrical appliances in the rooms. It was in wonderful Rusglish.
BC

Well, I don't know your nationality but I have to say, exemplified here is the spirit that won us the wars (yep , both of them)

[Heatercathodeshort]

The water itself is the element.
I used to get many electric kettles in for repair with the complaint that they took up to an hour to boil. The element casing had cracked allowing water to enter eventually blowing the whole element to bits leaving just a broken spiral element and the remains of the outer sheath. The current simply passed through the water via the O/C element to the earthed kettle's body. Complicated to explain. John.

[Lucien Nunes]

Electrode boilers are still made and used both for hot water and raising steam. They are usually large 3-phase installations in the hundreds to thousands of kilowatts range, either mains voltage or in the larger sizes high voltage. Unlike portable devices they can have multiple, secure connections to earth, plus differential leakage current monitoring may be provided. The inherent symmetry also helps minimise leakage current under normal operation.

I have seen pictures of a permanently-installed domestic over-sink electrode water heater which I think was French. IIRC it was 3-phase, which was more practical in mainland Europe where 3-phase domestic supplies were fairly common.

My parents have a steam-raising humidifier that consists of a small enclosed electrode boiler inserted into a reservoir of water, both insulated to Class II standard so the unit needs no earth. To re-fill, the boiler is removed completely from the reservoir which opens a double-pole interlock switch, although the electrodes are concealed behind a grille so direct contact is prevented anyway. It has outlasted many other units with sheathed or concealed elements, and cannot overheat if the water runs out.

[ex 2 Base]

3 phase electrode water boilers use to be common in slaughter houses where very large volumes of hot water is required very quickly. Also, simple electrode water boilers/ heaters/shower units are common in the Middle East,plugged into a two pin socket outlet in the shower room/toilet, never heard of anyone dying from electric shock. One could sit on the toilet and have a shower. Happy days.Ted

[turretslug]

Again some decades ago, when my folks had central heating fitted in their house, the original immersion heater was removed from the now redundant direct ("back boiler") cylinder- the outer sheathing jacket had completely vanished just leaving a loop of resistance wire dangling down from the boss. Goodness knows how long it had been working fine like that but one of the fitters reckoned it wasn't unusual! Hence the availability of immersion heaters with pricier corrosion-resistant sheathing.

[broadgage]

The Barbican arts centre in London used electrode boilers for heating and domestic hot water when I worked there in the late 1980s. Off peak electricity was used, at 11KV IIRC.

A variety of safety features were installed and AFAIK the installation gave satisfaction.
I think that the equipment operated at just over 100 degrees centigrade being under modest pressure. As the pressure rose, the water was displaced from the actual boiler and replaced with steam which being non conductive limited the current flow.

Don't know if the equipment is still in use, it was newish then.

[G6Tanuki]

Remember that [pure] water is an insulator! So immersing a heating-element in [pure] water shouldn't be a problem.

I recall some high-power [hundreds-of-Kilowatts] transmitter-valves with water cooled anodes - the copper pipe cooling-coil integral with the anode-block was supplied with water by way of a couple of clear plastic tubes each about 35cm long to provide both RF and DC isolation.

The plastic pipes were attached to the anode-block flow- and return-stubs using ordinary "Jubilee" clips, which amused me at the time - it looked more like something you'd expect to see behind a tropical-fish tank.

I guess if 35cm of water can insulate to 25Kv or so then 240V is going to be a trivial matter.

OK, this assumes *pure* water - if your water's been sitting in a skanky old tank in the attic for who-knows-how-long, or it comes from a Scottish burn so sometimes runs brown with organic acids washed out of the peat, then beware!

[TonyDuell]

But of course pure water is useless in an electode boiler which depends on current flowing through the water.

[dseymo1]

I'm more inclined to think that it's just a couple of electrodes immersed in the water stream. There were certainly 'static' water heaters on that principle.
There are far-Eastern electric taps on sale today which are essentially the same as this item, but whether they have elements or electrodes is unclear.

[hannahs radios]

When I worked for Daly Condensors here in Weymouth we had 2 electrode boilers that provided process steam for the production area and hot water for the Anodizing plant I know the anodizing used deionized water so how they heated it in an electrode boiler I don't know maybe some sort of heat transfer system?? Also if you guys look up kreosans channel on you tube in one video they heat water and food usind the electrode methods straight off the 220 volt mains have a look I'm going to try it see how it works

[McMurdo]

I always thought potable water and food heated by electrode ended up tainted due to erosion of the electrodes and other electrochemical effects altering the taste.

[Heatercathodeshort]

Ha! ha! I don't think it was designed to be used for making fancy coffee! John.

[hannahs radios]

Mcmurdo I don't think using an AC supply will affect the taste because any electrolytic effects are reversed and there for there will be no effect I think if you were using DC mains it would be a different story then ide be worried about metal migration from the electrodes to the food.