Wednesday, 30 May 2018

Untitled Post


The Compact Color Medium Pressure Mercury Lamp



Imagine your Light Community outdoor environment lit with egg-shaped big lamps in all the colours available for neon-signs... You have them no where, excepting some coloured metal halide lamps, in certain colors only.

Proposals for research will come into discussion in order to discuss and achieve lighting sources for esoteric purposes.

A web page will be dedicated for discussion. Till then these only are available:


http://lightcommunitylighting.blogspot.com/2018/04/blog-post_13.html

Look here a random example of neon-signs color range:

https://www.custom-neon-signs.com/Colors

Briefly, in order to achieve each of this color with compact egg-shaped mercury lamp, you have mainly to find so:

- a discharge tube to provide the needed amount of UV in order to irradiate the fluorescent coating of the egg-shaped bulb.

- the needed amount (area of bulb) of fluorescent coating to provide the minimal desired lumen output, if proper irradiated with UVs.

- a proper balance between the heat output of the discharge tube and the size of the (egg-shaped) outer bulb, in order to NOT overheat the fluorescent coating,... which in case of neon signs is not so heat-resistant.


This last item might be the most 'dangerous' one. It might be what prevents a proper color to be achieved and the premature damage of the coating.
This is an important item which the research must solve...


NOTICE!
Discussion about the 'medium pressure mercury lamps' (Ar+Hg) do not include the proposed 'medium pressure neon-mercury discharge lamp', which is a case itself.
This one will use for research the 'common' phosphorous coating for HID mercury lamps. It's main light spectrum is expected to come out from the discharge itself, and will be a reddish based spectrum. Let's say from light-cyclamen to violet-red, depending of the balance between neon and mercury (in discharge terms, not in 'weights').



Here some examples of 'medium pressure mercury':
In that catalogues are some 'low power' already existing (so having 'proof of time') UV medium pressure arc tubes, which (at least theoreticaly) may be used for our proposed medium pressure mercury lamps.
If you or other readers are also in knowledge you will immediately say 'yes' or 'not' as your opinion might be...
The item of interest in the catalogue are the 2 400W medium pressure mercury lamps (arc tubes) which burn in any position (not only horizontal):

HP 4/120 400 125 3.5 120 410 31 105 14.0
and
HP 4/120 SE 400 125 3.5 120 410 31 111 14.0
The arc tube is 31mm length and 14mm dia.

They also run at 120V arc voltage and 3.5A, let say 'nearby' the common HID 400W mercury lamp...
What is also interesting in the catalogue are the Medium-pressure metal halide lamps (not used in general lighting), from which the point of interest is that of 460W

HPM 12 460 120 4.1 800 44 98 22.
The arc tube is 44mm length and 22mm dia.

Thus we might to prefer even a lower power one, this one needs however to be taken in consideration.

On the other hand, we might say that the 'medium pressure' is 'missing' from the metal halide lamps 'portfolio'... The case is also for the sodium lamps...
Here a 250W metal halide UV arc tube. However no arc-voltage and amps.

250 5000089 MHL-250 15.5 68 18 300-450

https://www.ushio.com/files/catalog/uv-mhl.pdf

However the medium pressure MH lamps seem to be weak in the 250-260 nm, while the medium pressure mercury ones seem somehow reach.

Give a look to the bulb in this link:
http://www.fisherylight.com/metal-halide-fishing-lamps/2000W-on-boat-metal-halide-fising-lamp.html

It is a so called 'fishing lamp' (in fact a fish lure lamp used for ocean fishing).

But, of course our point of interest is altogether different, you guess it...

It is a big sized bulb, let say 'big as a house', thus it's not even so... :-)

Consider it to have 200mm/8in dia and an E40/Mog screw cap.

Now! imagine instead of its arc tube (of 2000W) one of the arc tubes above described of 400W medium pressure mercury or metal halide arc tube.

And, the more, imagine it coated with the fluorescent coatings in discussion used for neon signs, or as case for fluorescent tubes.

The arc tube is supposed to provide an amount of UVs, enough to irradiate the large area of the inside coated surface of outer bulb.
However, there is the need of sufficient amount of spectral emission in the appropriate wavelengths which properly match the sensivity (in wavelenghts) of the coating, in order to have a convenable conversion work of the phosphorous.

Now it's ready for research! Of course you need access to a plant where this kind of bulbs are currently manufactured. In Asia there are many, many that can do it at a reliable price.


Discussion to come to imagine the experiment...









[Image posted for educational purpose only]



Tuesday, 22 May 2018

The Medium Pressure Neon-Mercury Discharge Lamp



The Fluorescent Coated Medium/High-Pressure Neon-Mercury Lamp as Another Attempt to Achieve a Light Source for Esoteric Purposes


RESEARCH PROPOSAL

What should it to be, how it to look like...
What to put together from what is available in nowadays tech, and what to bring new in...


- Proposed shape/outlook: A fluorescent coated ED28/ED90 bulb shape with an E40/Mog screw-cap. As case may be, also with an E33 screw-cap.  



  Depiction of clear (uncoated) bulbs,
for a better description of inner details.


- Proposed/expected rated power: 175...250W for an ED28/ED90 bulb.

- Expected compatible ballasts: Metal halide ballasts of 150W/1.80A, and mercury or metal halide lamp ballasts of  250W/2.15A, 50/60Hz, as the case may be.


- Discharge tube: That of the size used for 400W mercury lamps, but made by alumina silicate hard glass instead of quartz, and with electrodes similar to the 250W mercury lamp, for the case.

 In fact there is a larger than usual  '250W' arc-tube, but with proper (not oversized) electrodes, and,  a gas mixture filling containing mainly Neon and Mercury.



HOT CATHODE NEON ARCS – C. G. Found and J. D. Forney. (Journ. Am.I.E.E., December, 1928, V. 47, pp. 855-859.)
 "In general, we believe that the hot cathode neon arc is the most efficient high-intensity source of red light." 
"The substitution of a hot cathode reduces the cathode drop to a few volts and all the difficulties caused by the high cathode fall are avoided. At a pressure of 2 mm, practically all of the tube is filled with positive column and a current of about 3,5 amps is produced when the heater is taking 60 watts. The tubes are started (1) by bringing an HF discharge close to the cathode; (2) by an auxiliary starting anode; or (3) by an inductance 'kick'. Various types are discussed together with their uses and advantages: important features being their long life and their independence of surrounding temperature." 


Discussion to continue...






Cobra's up to date post:  http://2012portal.blogspot.com/2018/05/firing-grid-update.html