Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

Pedro,

1) a bulb can explode before its nominal lifetime is up.
2) it has happened to me once in the last 12 years
3) most of the time bulbs flicker, become unstable, and eventually
just fail to ignite
4) I once had a Hg bulb that was operating fine after 1000 hrs. (I
inherited it). I changed it even though there was no evidence of
impending failure. It scared me!
5) Initial installation and startup of the bulb is very important.
The bulbs operate at something like 900 deg. C. The general rule is
let them run for 5 or 6 hours so that stable arc points are
established. If there is any unevenness in heat distribution because
the bulb surface was contaminated by careless fingers or even dust
carbonizing on the surface, the bulb is at risk. The stress on the
bulb is greatly affected by any uneven heating and heat conduction
away from the surface
6) Re-igniting the bulb before it has cooled down is asking for trouble.
7) No microscope room should be without ventilation, if for no other
reason than the ozone generated by the lamp. Though I have never used
one, a Hg trap in the outward ventilation duct would not be a bad
idea.

Finally a question: does anyone know of a documented case of a person
suffering Hg poisoning from an exploded microscope lamp?

Mario

>Search the CONFOCAL archive at
>http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
>
>Hi all,
>
>not strictly confocal, but I would like to know how real and serious is
>the risk of explosion of a Hg bulb when used after its nominal lifetime
>( in my case 200 hrs).
>
>Thanks in advance
>
>
>Dr Pedro J Camello
>Dept Physiology
>Fac Veterinary Sci
>Univ of Extremadura
>Campus Universitario
>10071 Caceres
>SPAIN
>Phone/Fax: 927-25-71-54
>[log in to unmask]


--
_________________________________________________________________
Mario M. Moronne, Ph.D.
NanoMed Technologies
FAX (510) 528-8076
1561 Posen Ave
Berkeley, CA
94706

[log in to unmask]
[log in to unmask]
[log in to unmask]