What Is The Spectrum of A Mercury Lamp?

Mercury lamps remain vital in coating and printing, particularly where UV curing machines dominate. Mercury lamps can excite UV light, which is of exceptional value during curing. But now the puzzle is on the spectrum of mercury lamps. This post will review the composition, characteristics and role of its spectral output on UV curing.

How does a mercury lamp run?

It turns out that mercury lamps are gas discharge lamps. They, therefore, rely on ionizing the mercury vapor in the sealed glass chamber to provide light. These lamps have a small amount of liquid mercury, which vaporizes when the lamp is turned on. As electric light passes through, the vapor excites the mercury atoms to produce light.

Mercury lamp spectrum

Mercury lamps have different spectral lines. Each corresponds to different wavelengths of light excited by the mercury atoms. So, the three lines are normally the visible light, infrared and UV region. In this case, the focus is on the UV spectrum region.

UV spectrum region

The UV region of the mercury lamp again has three segments. These are the UVS, UVN and UVA. For instance, the UVC has the shortest wavelength at about 100 to 280 Nanometers. But it is the most harmful segment. UVB range features 280 to 315nm and can cause burns. Lastly, the UVA is responsible for UV curing with a 315 to 400nm range. It has the longest wavelength in the UV region.

What’s the importance of UV curing?

UV mercury curing involves using UV light from a mercury lamp to polymerize UV-curable stuff like ink, coatings and adhesives. The spectral output of the mercury lamp determines the efficiency and performance during the curing process. As for the UV curing materials, they contain photo initiators.

These are used to absorb specific wavelengths of UV light. They then start a cross-linking reaction, which brings about the curing effect.

Since mercury lamps excite different wavelengths, the prominent spectral lines are the 254nm UVC and the 313, 365 nm UVA. These lines match the absorption patterns of most curable materials. As it is, matching the emission spectrum to the photo initiator spectrum allows maximum transference of energy for fast curing.

What are the challenges within the spectrum of a mercury lamp?

Mercury lamps are not without limits. Mostly there is an unwanted spectral line outside the needed UV range. As a result, you may need filters or optics to manage them. Again, the intensity of UV light from the mercury-curing lamp decreases as the mercury in the lamp depletes. Regular lamp replacement for consistent performance is a must.

What are the applications of mercury lamps?

Mercury curing lamps are used in the printing, coating and adhesive industries. In printing, they are deployed in UV offset printing, flexography, and digital printing, facilitating fast curing of inks. On coating, they are a component of the powder coating oven where the coated item is placed for curing.

Which factors determine the spectral output variations of mercury lamps?

The lamp design, pressure and temperature may impact the overall performance of mercury lamps. So you have to single out the appropriate lamp for the desired applications. There are also advanced mercury curing lamps with improved stability and control on the spectrum.

Safety considerations for mercury lamps

There is UV radiation from mercury lamps and a risk of mercury poisoning from the mercury vapor. Your working unit has to be properly ventilated. Remember to put on UV-blocking goggles and ensure you follow proper mercury lamp disposal procedures.

What are the alternatives to mercury lamp?

Recently, UV light sources like LED-based systems have been gaining popularity for energy efficiency, longevity and narrow spectral output. They allow precision over the emitted wavelength for the optimal curing process. Even so, mercury lamps continue to be the preferred choice.

Conclusion

The spectrum of mercury lamps has different wavelengths, but now focusing on the UV region, there are about 315 to 400nm. Even so, understanding the spectral characteristics of mercury lamps can allow you to work optimally on your curing substances. Yet, mercury lamps may have difficulty when controlling the spectral output.

And it is not bizarre to see companies like IUV making highly accurate mercury lamps. While this may be a problem, you can navigate it by choosing a reputable manufacturer for your mercury lamp.