Assumed September 2011. Code
08/0911 stamped on lamp.
Compact fluorescent lamps have been commonplace for a
good long while now, and they have come a long way since their
introduction a little over a quarter of a century ago. In the last
ten years though we've only really seen refinements to established
designs. There haven't really been any products appearing on the
market which have been truly original. This thing I think does
A few years ago, I recall stumbling across a website for
a design project to create an artistically inspired compact fluorescent
lamp. Some of the designs there were really quite eye catching and
elaborate. Given the manufacturing challenges in putting them
together though I dismissed it as something that was interesting, but
unlikely to ever see the light of day on a production line.
Suffice to say that I was rather surprised when only a
couple of weeks ago I spotted one in a John Lewis window display.
After stopping abruptly enough on the pavement that the person behind me
nearly crashed into me, I immediately went and hunted one down in their
lighting section. Sure enough, the name on the box was the one I
remembered from the suspiciously similar looking project online, Plumen.
Given that there is one of them sitting on my desk as I
write this it seems that my predictions that the Plumen would never be
more than a design prototype curiosity were rather unfounded, and on
this occasion given how fantastic looking a bit of lighting equipment it
is, I am glad to be proven wrong. Fantastic looking it may be, it
is however equally fantastically difficult to photograph!
From a technological perspective this is a very ordinary
compact fluorescent lamp. It has an electronic ballast just like
any other, and a perfectly ordinary colour 827 phosphor, and aside from
being a rather odd shape, the tube is very ordinary. The greatest
challenge in creating this lamp has been how to reliably form the
intricate tube shape without causing excessive degradation of the
phosphor, as the usual challenges which apply to spiral compact
fluorescents are also present here.
The main problem is that the phosphor is applied as a
powder suspended in a liquid which is flowed through the tube during
production. In linear tubes this is simply done end to end, and
due to the action of gravity it is easy enough to get an even covering.
With a spiral tube however this action invariably results in a far
thicker band at the bottom of each spiral where gravity causes the fluid
to run to. This gravity caused phenomenon is highly undesirable as
it results in the top of the tube being phosphor deprived, resulting in
a loss of light output and the colour temperature wandering off from
where it should be due to the increased transmission of the mercury blue
lines. The thicker phosphor at the bottom of the tube results in a
dark band and reduced light output there. The question may be
asked "why don't you just coat the tube before you form it then?"
however this does not come without a price either. The heat of the
forming process invariably damages the phosphor to some extent, and the
stretching of the tube on the outside of the curve results also in the
coating there being far thinner than it otherwise should be. On
conventional U shaped compact fluorescents this is permissible, as the
U-bend section of the tube represents a relatively small percentage of
the total tube length. When dealing with a spiral (or similarly
curve-intensive design like the Plumen) it's rather more of a problem
though, so the former option of coating after tube forming is generally
taken. The spiral CFL is rather a compromise by its very design
due to the aforementioned phosphor problems, hot running temperatures
and relatively poor optical efficiency, however the compact size of the
lamps they allow to be created are generally seen as a worthwhile trade
off. The approach used for the phosphor deposition on the Plumen
001 appears to be the usual "pour it down the tube after forming it"
approach as is generally used these days for spiral CFLs.
The tubing appears to have been formed by a vacuum
forming process judging from the mould lines apparent on the tube
curves, which is no doubt a far more reliable way of forming the precise
curves needed here. Given that the two tubes on each Plumen are
identical to each other and are interlocked when fitted into the base,
they need to be pretty precise. They are actually two completely
separate tubes, connected in series as is often done with the different
tubes on neon signs. This arrangement offers greater flexibility
in terms of positioning than the usual tube-to-tube connections you
generally see with the tubes actually fused together. In this
case, that arrangement would of course be impossible to use due to the
distance between the tube ends.
Electronically it's very ordinary, just a garden variety
HF electronic ballast in the little black cap. I have to confess
to being somewhat disappointed to see that it's an instant start
ballast. Given that this is a £20 lamp, I would honestly have
hoped for a programmed start ballast here to prolong the life of the
lamp - or at the very least a simple soft-start device to preheat the
tube electrodes. Given that this is a lamp which really isn't
designed to be hidden away behind a shade, taking measures like that to
minimise blackening around the electrodes would have been commonsense I
would have thought.
Light output is pretty good for a 11W lamp, and the
usable light is probably a bit higher than in most cases for a very
Look at it. Really...Look at it - the whole idea
of this lamp is that it's not intended to be hidden away behind a shade.
That means of the 680 lumens it produces, they should all be finding
their way into the room, rather than several tens of percent behind lost
passing through the shade. There's even a special fitting
available from the manufacturer which is designed to show it off -
basically it's a lamp holder with a cup on the end which encloses the
base of the lamp.
As an idea, it is definitely interesting. I have
to admit to being very curious to see whether we will see any of the
other Plumen designs that I remember seeing on the website years ago on
the shelves in the future. I would like to think so certainly.
I reckon that if this was about £5 cheaper and had a
ballast designed to look after the tube better that this could be a real
success story. It's never going to replace conventional CFLs
outright, but I can see a lot of people, especially designers of hotels
and expensive homes really having fun with lamps like these.
Hulger Plumen 001 Decorative Compact Fluorescent Lamp - General
Hulger Plumen 001 Decorative Compact Fluorescent Lamp - Looking
down at the lamp showing the two separate intertwined tubes
added to the Virtual Display Shelf on the 26th February 2012 at 22:50.
References: Lamp packaging only.
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