Help save the last mercury arc rectifier substation

[mikeselectricstuff]

When I was at school, we made barometers by inverting a big tube full of mercury with our finger over the end into a bowl of mercury. This was in proper physics class, not messing about!
 

[Brumby]

When I was 12, in my first high school science class we had a new teacher.  She set up an experiment to show heat vs temperature for ice-water-steam.

After entertaining us with lighting the gas tap instead of the bunsen burner, she fitted one of those 12" mercury thermometers in a cork which was placed in the neck of the flask containing the ice/water mixture.  Having addressed the flame malfunction, she then proceeded to heat the flask.

All went well until the water started to boil - and then we had a ballistic event that would have inspired any budding rocket scientist.  The mercury thermometer was launched into the ceiling with such force that it completely disintegrated.  Yes, she did not provide any means for pressure relief.

We in the class were just amused by all this - and nobody started freaking out about the mercury.

Somewhere along the line, I know I've played with a bit of mercury.  I've even had some roll around in the palm of my hand - but that was just the once since I didn't want to risk losing any of such a cool material.  The thing I noticed, though, was how heavy it felt.  You just don't expect liquids to be that dense.

[Brumby]

Yes, I washed my hands.

When I was at school, we made barometers by inverting a big tube full of mercury with our finger over the end into a bowl of mercury. This was in proper physics class, not messing about!
 

Come to think of it, I have a vague recollection of that happening at my school - but by the teacher.  Don't remember if they made contact with the mercury.  We just weren't aware of such things.

[cdev]

Mercury is particularly problematic in old factory buildings.

Back in the day, energy was super cheap and buildings were drafty. So problematic mercury contamination of old warehouses and schools may not have caused the kinds of health issues it does now when air is confined indoors, until a successful closing up of all the air leaks had been done to save money on heating/cooling. This is likely one of the reasons why autism, etc. rates are rising, the rising costs of energy and reduced ventilation of buildings. Dilution is a solution for air contaminants. Poorer people cant afford as much ventilation in cold winter areas.

The classic example of this here in the US was a real tragedy. A site- 720 and 722-732 Grand Street in Hoboken, New Jersey. The area includes a former industrial building converted into 16 residential artist studio spaces at much effort and expense by an artists collective.

But at some point during the building's renovation, somebody discovered a space under the flooring that contained liquid mercury and this led to the discovery that the entire building and area was heavily contaminated  and many of the buildings residents were being poisoned by it. In the past it had housed a factory that made mercury lighting products, including a popular sunlamp used for indoor tanning.

[The Soulman]

Photonicinduction had one: (from 3:20)  

[Zero999]

Has anyone heard of one of a mercury rectifier exploding? What's the risk of it actually happening?

[mikeselectricstuff]

Has anyone heard of one of a mercury rectifier exploding? What's the risk of it actually happening?

Pretty negligible I think, other than from physical damage. I'm not sure what the internal pressure is normally, or whetehr it's under vacuum when cold, but  all the ones I've seen don't seem to have particularly heavy glass to resist pressure.

[amyk]

They operate in a vacuum. The metal-cased ones weren't completely sealed and so needed vacuum pumps to maintain that vacuum, which also continuously emitted mercury vapour into the air.

(Attached image is from this book, which is also very interesting to read.)