Monthly Archives: May 2014

RUVA – what it means and why you want it

RUVA: Reflector UltraViolet A

RUVA: reflector uv curing lamp cutaway design

RUVA lamps are lamps that have a built in reflector. This image shows a cutaway, with a regular lamp on the left and a RUVA lamp on the right. The reflector is like a paint that is poured inside the lamp before the phosphors are added. The reflector in this image is a 180 degree reflector, where half the circumference of the lamp is reflective material, and light is emitted out the other half, kind of like how a flashlight only shines in one direction. The image shows that the light is reflected before it leaves the lamp, which makes it twice as effective as an aluminum style reflector. In general, you increase the UV output of any lamp by 35%-50% by using an internal reflector like this.

A reflector can be any size, although 180 degree and 210 degree (slightly more than half of the lamp is reflector) are the most common. I’ve personally set specs for lamps that had 120 degrees of reflector (the original SunMaster ReFlex series) and some that had 230 degrees. Theoretically, once you get over about 210, they are commonly called aperture bulbs or lamps. There are some that have about 300 degrees of reflector, so the light is all emitted through a small 60 degree slot. The smaller the slot, the more intense the output is, up to about the 300 degree mark. I’m currently designing some 230 degree aperture bulbs for prototype testing as I write this.

RUVA lamps emit light in just one direction, which is a plus for most application, but not all. One of the distinct advantages of a RUVA lamp is that it can often eliminate the need for an external reflector system altogether. Even on a good day, the shiniest aluminum is only good for about 50% reflectivity (the rest is absorbed/ionized as heat). When lamps are very close together, aluminum reflectors are basically worthless: The light gets ionized (or destroyed via wave cancellation) before it has a chance to strike the target, so the majority of light that is emitted away from the target is simply lost forever. Since over half of the light from a regular lamp will always shine AWAY from the target, we are talking about a lot of ultraviolet.

In some cases, an external reflector system can actually augment the built in reflector. The most obvious example is a guitar curing rig. The best ones are around 4′ x 3′ inside dimension, and use 16 FR71 lamps, all facing in (usually in a 5/3/5/3 lamp configuration). You can take spray glue, crinkle up some aluminium foil just a little so the light is diffused instead of hard reflected, and install it on the inside walls with the shiniest side facing the center of the cab. There is so much light bouncing around the cab (1600 watts worth in a 12 sq ft. footprint) that the foil is good for another 10%-15% or more. It can also be used at the top and bottom to get under and over the instrument with a little extra power. It isn’t required, but in some applications, the extra power pays for itself pretty quickly.

RUVA lamps also have slightly different heat characteristics, as the reflector seems to reflect infrared just as it does visible light an ultraviolet (UVA and UVB). This isn’t necessarily good or bad, it is just different. In one respect, it can be handy as the lamps tend to heat up quickly, so if you cycle the lamps a lot, it helps reduce cure times by a small but measurable amount of time. They produce the same amount of heat as a standard HO lamp, but they push a little more of that heat towards the target of exposure. In an open designed curing rig (the overwhelming majority of rigs are open design, unlike a tanning bed), it makes no difference to the target being exposed.

So why do you want a reflector? Because it adds 10% or so to the cost of the bulb, but increases the output by 50% in most applications and makes the design of most UV curing rigs much simpler. In short, it saves you money and reduces the time to cure. This is why virtually every bulb we sell for UV curing (or hydroponics use) has the RUVA system. We don’t make a non-RUVA version for price point advantage because we don’t want to build inferior lamps. If you need non-reflector lamps for some special application you can always call, you might be surprised at what we have in the labs at any given time. Most of you, however, want the RUVA system because it just makes life simpler, particularly for UV curing rigs that have only one row of bulbs instead of a surround-style design, like you would use for surfboards or curing other flat surfaces.

Dennis Brown

Plant stressing – A brief overview

Plant stressing is a fairly new concept, and someone could probably write an entire book on the subject. I expect someone eventually will, but for now, let me share a little basic theory, as well as some of the practice.

I’ve been familiar with the idea of plant stressing with ultraviolet for about 5 or 6 years.  The first person to approach me with it was a cannabis grower from California, I honestly forget his name.  He grew legally, for medicinal use, and had heard about using UVB as a way to increase THC, or tetrahydrocannabinol, the psychoactive compound in cannabis that is responsible for getting you “high”, treating pain and inflammation, reducing nausea and increasing appetite in chemotherapy patience,  and has a number of other medical uses.

At first, it sounded like left field science until I did a little research on trichomes, then it started making sense.  Within a couple of years, many people were asking for UV lamps for a variety of plants, in particular, tomatoes and cannabis.  After some trial and error, we were able to dial in on the specific frequencies that get the best results, and of course, that formed the basis for our current lamps.

Most of the testing has been with plants that have trichomes, including of course tomatoes and marijuana but also peppers of different types, and even some non-trichome plants such as flowers, although at lower levels of ultraviolet and for different reasons.  The theory is pretty simple, that plants act similar to humans, and they protect themselves when exposed to the damaging rays of UVB.  The role of UVA is still not fully understood.

When a human is exposed to UVB, our skin reacts by producing melanin, which is a natural sunscreen.  UVA causes melanin to oxidize, which means to turn brown.  That is how people get a tan, and a tan protects you from damage from UV.

In some ways, plants (particularly those with trichomes) are similar: If you expose them to UVB, they will create a resin that acts as a sun block.  In the case of tomatoes, that sunblock is called flavonoids.  In the case of cannabis/marijuana, it is specifically THC which is a somewhat clear resin that is exuded from the trichomes on the flower and sugar leafs of the plant.  The art lies in causing just enough damage to the plant to get a reaction, but not enough that you damage its ability to produce flowers.  Typically, UV isn’t used until the plant begins flowering.

The same is true with tomatoes, you don’t really benefit from UV until the plant has already been pollinated and fruits begin to appear.  In all plants, it is during the fruiting or flowering phase that it benefits.  Before you ask, I am talking about tomatoes grown in a greenhouse, which my sources say are the majority of tomatoes grown in the US now.  The glass from the greenhouses filters out most of the UVA and all of the UVB.  The greenhouse is otherwise a perfect environment, since they never see a storm, supplemental lighting can change the length of the day or insure they never see a cloudy day.  Adding UV lights simply replaces what they would normally get if there were grown outdoors, and in the end, makes the tomatoes taste much more like outdoor grown tomatoes.

Anyway, that is the raw, basic theory behind plant stressing.  In the coming weeks and months, I will share more info and specifics.  If you are a university that wants to test some of these theories with UV lamps, you need to just call meat 800-600-8118 x126.  We have a few universities that are already using our lamps (including some big names I can’t mention) but in exchange for test results, we can subsidize the lamps, making it cheap or free to test.

Dennis Brown

Let’s talk a bit about ballasts.

Most of you are familiar with ballasts, you have to have one to power a fluorescent lamp. Fluorescent lamps aren’t self-regulating like a screw-in incandescent light bulb, they need something to push and regulate the power to them, thus, we have the ballast.  Without a ballast, the amount of current the fluorescent lamp was drawing would quickly increase until the lamp explodes.  I haven’t actually seen that, but I’m confident enough of the science to just take the engineer’s word for it.

If you haven’t paid attention, ballasts have radically changed in the last decade or two. It used to be a matter of finding a ballast that is rated for the ultraviolet lamp you are trying to power, then buy and install it. This is most obvious with choke style ballasts (ie: ballasts that use an off board lamp starter) but is also the same for magnetic or the first generation electronic ballasts. If they were rated for 40 watts, then they pushed 40 watts, no matter what you had connected to them. This isn’t the case any more.

I’ve worked with a number of different ballasts over the years with tanning beds as well as custom curing rigs. Literally every type you can name. What we’ve found is the new style is superior, although a bit quirky. If you put a hertz meter on the lamp end, you find that magnetics and older style electronic ballasts operate in the 10,000-25,000hz range (choke ballasts work at the same hertz as the feed cycles, 60hz here in the US). The newer electronics work at 100,000 or higher, which we presume is more efficient at exciting the mercury atoms; the heart of how a fluorescent lamp works.

The quirky part is that they are self adjusting, to a degree. If you put a shorter lamp on them, they will draw less power. If you put a longer lamp on them, they will draw more power, up to their power limit. This lets us use the same ballast in a number of different power configurations. The best example is the Workhorse 8, which has six red leads. You can power six F32 lamps, or four in HO mode. You can also power three F71 lamps in HO mode, or even four, five or six in lower power modes. If you use two of the red wires per lamp, you can power two F71 lamps in quazi VHO mode. If you wire three F71 lamps with one red wire per lamp, you get a different output than if you wire them with two red wires per lamp. Of course, you can power four F59 lamps, and I’ve even used them to power F14T12 lamps. More confusing, the less F32 lamps you run on the ballast, the higher it powers each. It is likely one of the most flexible ballasts for pushing UV lamps, if you understand them and you are willing to use an ameter to measure the output. Keep in mind, some of these configurations aren’t “certified”, although commonly used.

On the regular website, we list a number of different configurations for each ballast, which might seem confusing at first but it is actually easy once you have the basics down, and erase the idea that the ballast delivers a fixed current out of its leads.

Dennis Brown

Hello from Solacure

Thanks for the patience while we transition over to the new domain and website.  This has been a few years in the works, but the new domain and name means we can focus more on UV curing and horticulture and increase our support and product line.  Good things are coming.

I will posting stories from customers, some basic ideas to help new customers get started, and general information.

Dennis