Corona treatment of materials has a wide variety of uses in the industrial world. Uses include the removal or addition of charge from large surfaces, creation of ozone, treatment of polymers to increase compatibility with inks or adhesives or in the biotech world, treatment of tissue cultures on polysytrene. Electro-Technic Products, Inc, a small company out of Chicago, makes 2 corona treaters for almost any application. The first and smaller of the two is the Laboratory Corona Treater Model BD-20 and the other, larger of the two, is the High Frequency Corona Surface Treater Model BD-80. The context of this review and my primary experience with corona discharge is with the treatment of materials to alter hydrophobicity.
The first and smaller corona treater from Electro-Technic, the BD-20, is useful for smaller benchtop applications or perhaps in an educational environment. The output voltage ranges from 10,000 to 40,000 volts at 4 to 5 MHz. This is a moderate field strength and is useful for treating small objects placed on a table top or pinhole detection. The treater needs to be fairly close to the item being treated and treatment time is moderate (around 10 - 100 seconds depending on size), although these values will vary depending on the treatment strength the user requires. The treater itself is fairly compact, cylindrically shaped, about one foot in length and 3 inches around. The physical build is fairly robust and is durable. Available in a package, the treater comes with a power source and a variety of discharge tips. The different tips are useful and allow the treater to be used for a variety of purposes and are of excellent quality.
I would rate the actual function of this smaller treater to be fair. Although the treatments I obtained from using this gun were adequate, resulting in large changes in hydrophobicity, there were a few small issues with the treater after long-term use. First, it is not possible to operate this treater continuously for more than 10 minutes. The treater will overheat causing extensive damage to the treater components if it is operated for an extended period of time. If you have very large treatment requirements, the larger BD-80 model may be more appropriate for your uses due to its ability to be run continuously for an unlimited amount of time. Another source of trouble I had with the smaller treater was the power adjustment knob. The knob itself is fairly rough in function and will eventually seize when the treater has been used too long, rendering the treater useless. From my experiences, the treater slowly loses power until it will no longer generate a field. It must also be mentioned however, that while under warranty, Electro-Technic quickly refurbished the treaters at no charge. Again, this problem may be addressed by obtaining the larger BD-80 treater. The level of ozone generated by this treater is fairly minimal and is not a problem in an open room. If being used in an enclosed area, I experienced ozone levels approaching unsafe levels which can be measured by a small electronic ozone meter. Use of this treater will require a ventilation system in the work area.
The BD-20 is priced fairly considering there aren’t many manufacturers of such products. The BD-20 comes in a package with several treater tips. If you are on a budget, however, the treater is also available with a single spring tip for $328.00.
The BD-80 is a much larger unit and comes with your choice a one tip, depending on application. This unit is physically much larger with dimensions about 20 x 15 x 27 inches. The specifications are listed at 50,000 to 250,000 V at 2 MHz, which is much more power than most people will require. The benefit of this treater, as listed above, is that it can be run continuously for very long extended periods of time. According to the technical representative at Electro-Technic, this unit can be run continuously for an indefinite amount of time, however, I have not tested this. I have run it continuously for 3-4 hours with absolutely no problems. The other benefit of this treater is the immense power. This allows items to be treated with a strong field from a longer distance, converging a much larger area at a greater speed. The power of this model is almost overkill, requiring some careful attention to not destroy your samples due to overtreatment.
The BD-80 build quality is good, possessing a 1960-ish space age quality due to its analog control design. Perhaps the only drawback to this treater is its large size and weight. A large area is required to mount the treater, which is not easy due to its heavy weight of over 100 pounds. The manufacturer does offer a stand for the BD-80, which I have never seen so I cannot comment on its quality. Additionally, this treater generates a fair amount of ozone and has a built in ventilation system. The controls are durable and robust and the BD-80 has power controls which are easier to use than the knob on the BD-20.
The operating manuals for both treaters is fairly substantial. They contain instrument specifications as well as installation requirements and instructions for operation, calibration, maintenance, repair. A helpful primer on the corona surface treatment, which I found useful, is also included.
Overall, these are useful and well-built tools. Although they are not too cheap, the price, in comparison to many other scientific laboratory instruments, is minimal. Which treater to purchase is primarily a function of the use and throughput desired by the user. If your intention is to perform benchtop, small corona treatments of smaller objects, the BD-20 or a duet of BD-20’s will be sufficient. If you require either larger areas to be treated or high throughput treatment, the BD-80 will do the job. I would suggest to users that they seriously consider immediately obtaining the BD-80 if they are planning on scaling up, due to the BD-20’s problems with high throughput use.
Scientist
Research and Development
Gentel Biosciences