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This list will be continually updated. If you don't see the question/answer you were looking for please e-mail or call us. Cooling Air: Blower Sizing and Ducting Cooling Air: Blower Sizing and Ducting Q. Why do UV curing systems need cooling air? Can I just follow common HVAC blower and ducting design practices? A. All UV curing lamp systems require some type of cooling to ensure proper operation. A Fusion UV irradiator requires a certain amount of air to maintain the magnetron and bulb surface temperatures at optimal performance. While the blowers and ductwork may look like typical heating and air conditioning blowers and ducting, the requirements are very different because the volumes and velocities are much higher in a UV system. As a result it is very important when installing a new system or making any significant changes, such as moving blowers or changing the number of lamp units operating, to alert whomever is specifying or installing the blowers and ductwork that the design requirements are very different than what they are probably used to. Fusion UV typically recommends blower sizes based on the number and type of UV systems installed and an assumption about blower location and length of duct run. Sometimes problems are encountered because the blower is placed much further away, or the duct size or routing is very different than that assumed originally. These problems can easily be avoided if you pay attention to what was originally assumed and to the air requirement specifications for the lamp systems. If a blower must be placed farther away than originally planned, then it may need to be a larger size. Fusion UV's technical service and applications engineers can provide guidance. So if you are just installing a system or plan to make changes, give us a call first to make sure blower sizes and duct runs look adequate. For more detailed information visit www.fusionuv.com/blowerducting. Q. How can I reduce the heat from the UV lamp? It's damaging my substrate. A. A UV lamp system not only produces UV light but infrared radiation, or IR. In some applications excess heat can damage sensitive parts, cause wrinkling on printed films, adhesion failures, etc. In other applications heat can be beneficial by improving the 'flow' of the UV curable ink, coating or adhesive onto the substrate surface and in others by improving the cross-linking of chemistries. The main source of IR is the quartz bulb. As the bulb gets hot, it emits IR energy. The amount of IR emitted from a bulb is primarily a factor of its surface area. A larger bulb diameter means a larger surface area, therefore higher IR emissions. Conversely, a smaller diameter bulb has less surface area, therefore lower IR emissions. This is one key advantage Fusion UV's small diameter bulbs have over typical electrode type bulbs. Below are some suggested ways to reduce heat which may be damaging your substrate. Cooling: Fusion recommends that you remove 30% more air than is supplied to the lamp units so a negative air pressure exists under the lamps. Light shielding louvers are also recommended to allow for a free flow of make up air. As the make up air is pulled through the light shield it removes ozone and chemistry odors as well as heat from the substrate. Speed: The amount of heat that the substrate sees is also a function of how long it is being exposed. In some cases it is possible to increase the speed on the production line and still maintain a good cure, while reducing the amount of heat at the substrate. Reflectors: The standard aluminum reflector not only does an excellent job of reflecting and focusing UV, but also the IR. Another option to consider is a dichroic reflector. Dichroic reflectors have 50 or more layers of a dielectric coating applied to their surface. This coating allows UV light to be reflected, but absorbs much of the longer IR wavelengths. The heat is then dissipated from the reflector surface by air-cooling. If one of these methods alone does not yield the desired results, a combination can be very effective! More detailed papers in pdf format are available: Q. What happens if a system goes down shortly after the contract service has been completed? A. Fusion UV will handle this just as we would a normal service call follow up. We first determine the problem and the solution by working with the customer over the telephone, as this may be the fastest method of getting the system back up and running. If we cannot resolve the issue quickly, or if the customer prefers, Fusion UV will send a technician back to the customer site at no charge (or for "Return to Base" contracts have the systems sent to Fusion UV at no charge). If Fusion UV finds the cause was something we should have found during our inspection/service, we will add another cycle to the service contract at no charge to the customer. If customer negligence is the cause, then fees will be charged for these services. Q. How quickly does Fusion UV respond to failures after service? A. Fusion UV guarantees response within 48 hours. Q. Is there a warranty with the service contract? A. The Gold level contract carries a complete system warranty, same as new, for as long as the equipment is under contract. The Bronze and Silver levels are primarily inspection contracts, therefore the warranty will be limited to the contract specifics, however, if we missed something during service Fusion UV will make it right! Q. How do I verify proper air pressure in the lamp unit? A. An important part of any maintenance plan should include periodic verification of the air pressure in the lamp unit to ensure maximum life from bulbs and magnetrons. To test the pressure in the lamp unit, remove a screw from the face of the lamp (fig.1), insert the probe from a differential pressure gauge (fig.2) and measure the internal air pressure. Compare this reading to the minimum specification for your specific model lamp system. Model I601 Shown Filtered cooling air from a blower is fed into the lamp unit, passes through the magnetrons, and over the bulb through two microwave slots and a series of small cooling holes in the reflector. The air then passes out of the lamp cavity through the RF screen and is exhausted. In addition to cooling the magnetrons and bulb, this flow of air helps keep the bulb and reflector clean, which extends the time needed between maintenance cycles. For more detailed specifications and instructions, please consult the Installation, Operation and Maintenance Manual for your Fusion UV System or contact Fusion's Technical Service Department. Electrodeless bulb and reflector cleaning Q. How should I clean my electrodeless bulb and reflector? A. Bulbs and reflectors should be inspected for external contamination (the photo shows an obviously very contaminated surface) every 500 hours of operation. If you consistently find deposits on the bulb and reflector during inspection, consider changing the air filters more frequently. If the bulb or reflector surfaces show signs of dullness, dirt, oil or other contaminants they should be removed and cleaned as soon as possible to prevent any permanent damage.
To clean the bulb and reflector, use a lint free cloth and a cleaner that uses no waxes, silicones, dyes or perfumes such as Windex or Simple Green. Isopropyl alcohol or methanol can be used where solvents are allowed. In extreme cases of bulb contamination, a cleaner with mild abrasives such as Soft Scrub can be used, but it is extremely important to thoroughly rinse the residue from the bulb before re-installing it in your lamp system. Cleaners with abrasives should not be used on reflectors. Q. How can I tell what type of UV bulb I have? How do I know what replacement bulb to order? A. When installing a replacement bulb it is imperative to make sure you have the corect part. Check the part number of the bulb being removed and verify that the replacement bulb has the same part number. The figure below shows how to identify your Fusion UV bulb. Note the six-digit part number followed by a letter designation. When ordering replacements, only the part number is required. The most common Fusion UV bulb types are H, H+, D and V. Each of these bulb types has a different spectral output that is matched to your chemistry and application. The bulb shows here is an H bulb.
Q. After removing the reflector for inspection and/or cleaning and I'm ready to reinstall the reflector, what should I do with the RF gaskets? A. Any time you install a reflector, whether it's a new one or the old one, we recommend you install new RF gaskets. Never install the reflector without the RF gaskets - they are very important for proper operation and reliability of the lamp unit. Q. Why and how do I replace the RF gaskets when I remove or replace the reflector? A. The RF gaskets maintain proper electrical contact for the reflector, which actually forms the RF cavity for the microwaves energizing the UV bulb. Without proper RF gasket installation, component life and reliability of the lamp will be reduced.
Before installing new RF gaskets, lay them flat on a hard work surface and lightly tap them with the end of a screwdriver (Fig. 1). This will make the RF gaskets easier to install into the Waveguide slots. When installing end reflectors or new RF gaskets, it is important to position the end reflector into the Waveguide first, then install the RF gasket between the end reflector and the Waveguide slot.
The reflector will expand and contract with the constant heating and cooling of the lamp unit, which over time can cause the reflector screws to loosen slightly. To minimize this, we recommend that you run the lamp unit for at least 20 minutes; shut it off; let it cool down; remove the RF screen and then retighten the reflector screws through the holes provided in the RF screen frame. You may only get another turn, but this small step can greatly increase the component life and reliability of your lamp unit. In many applications, a small investment in better air filtration will pay off in reduced maintenance costs and less time spent cleaning bulbs and reflectors. For more information please consult your Installation, Operation and Maintenance Manual or contact your local Fusion Technical Service Office. Telling if a bulb is good or bad Q. How do I know if a UV bulb is good or bad? A. There are a few simple and inexpensive methods to determine whether a bulb is good or bad. Method 1: Some Fusion power supplies are equipped with "Photocell Test Points" that make checking the bulb very easy. Simply put your voltage meter on these test points while the system is in "Standby", if the voltage reading drops when the system is turned "On", then the bulb is most likely good. Refer to your Installation, Operation and Maintenance Manual for more information on photocell test points.
Method 2: On systems that do not have test points you can observe the system using view ports for safe observation to see if the bulb lights up when the system is turned "On". If it does, then a general rule of thumb is that the bulb is "good".
Method 3: To test bulbs that have been removed from a lamp unit use a High Frequency Generator. Place the bulb on a bench top and touch the generator probe to the bulb. If the bulb lights up as shown in the picture below, it is a good bulb. This method ionizes the gases at a very low level and generates an insignificant amount of UV, however Fusion recommends using UV rated safety glasses.
For more information on the high frequency generators or bulb testing in general, please contact Fusion Technical Service at Tel: 301-527-2660 x8500, Fax: 301-527-2663 or techservice@fusionuv.com. Calibrating Variable Power Supplies Q. Is it necessary to calibrate Variable Power Supplies (VPS)? A. Variable Power Supplies (VPS) do not require routine calibration. Every VPS manufactured and shipped from Fusion UV is calibrated as part of our normal testing procedure. However, you should re-calibrate if you have replaced the high voltage board, a high voltage diode, control transformer or swapped or replaced one of the magnetron boards. If the unit is in need of calibration it will display a "No Calibration" message. This re-calibration is important for two reasons. First, it ensures maximum useful life of the magnetrons and, secondly, it assures the operator that the power level selected will be accurate to within 2%. In other words, 100% is 100%! Testing and Troubleshooting Power Supplies
Q. What tools are necessary to test and troubleshoot power supplies? A. To accurately test and troubleshoot a Fusion UV power supply you need a Volt-Ohm Meter. However, there are three different types of Volt-Ohm meters, so be sure to use the proper type for accurate measurements. Below is a brief discussion of each and their proper use. Any of these meters can be used to measure the 3-phase, single-phase AC input power or DC voltages such as the photocell test points or control card diagnostics on your Fusion UV power supplies. However, only a True RMS meter should be used to measure the filament voltage because the waveform is not sinusoidal. A standard DVM will only produce a misleading voltage reading when trying to measure anything other than a DC signal or a sine wave. The filament voltage reading can differ by as much as 20 volts! A properly set filament voltage will ensure maximum lifetime out of your magnetrons, therefore it is important to measure and set it accurately. To measure magnetron currents a digital meter is required for accuracy. To diagnose capacitors and diodes, an analog meter should be used. In both cases, a meter with a minimum 6.0V battery is required to ensure accurate readings. For more detailed information consult your Installation, Operation and Maintenance Manual or contact Fusion Technical Service at techservice@fusionuv.com. Q. What routine/preventive maintenance does Fusion recommend for power supplies? A. Though power supplies are often overlooked when it comes to preventive maintenance, there are a few steps that should be taken to make sure your power supply continues to operate trouble free and at maximum efficiency. For more detailed information consult your Installation, Operation and Maintenance Manual or contact Fusion Technical Service at techservice@fusionuv.com.
A. Every Fusion UV lamp system includes an RF detector that shuts the system down if excessive amounts of RF energy are present. Fusion equipment is interlocked to shut down if microwave leakage in excess of 5mW/cm is detected. Fusion model RF-1 detector automatically tests the components of its circuitry at start up. For a manual check hold down the test button on the detector case for approximately 5 seconds. If you are faced with an RF fault from Standby to Lamp On there are a few simple things you can do to quickly isolate the cause of the problem: 1. Check the RF screen for damage and replace if necessary. The RF screen helps contain RF energy in the lamp cavity. A damaged RF screen may allow more RF to pass through than normal. As a result the RF detector senses the leak and shuts the system down. 2. With the system turned off, remove the RF detector from its mounting bracket while still leaving it connected to the RF cable and the power supply. Move it at least 10 feet away from the lamp unit and turn the system to On. If the unit no longer shuts down with an RF fault, but is now failing with a Lamp Out fault, then the UV bulb has failed to ignite and should be replaced. From several feet away the RF detector cannot detect a true RF leak. So if the system continues to shut down with an RF fault, then the problem is not going to be found in the lamp unit. The RF fault is the fastest reacting fault circuitry in the system. If a bulb fails to ignite and therefore fails to absorb the RF energy, there will be excessive amounts of RF passing through the screen, which the detector senses and shuts the system down. Once you remove the RF detector, the lamp photocell circuit senses that the light has not come up to power and shuts the system down with a Lamp Out fault. 3. Once we have ruled out anything in the lamp unit we need to look at the RF detector itself, or the RF cable that attaches it to the power supply. If you have a spare RF detector or RF cable, then swap them out one at a time to see if either resolves the problem. If you do not have these spare parts, but have other systems in your plant, then you can use parts from them as test units to determine which part is defective. 4. If the RF detector and cable appear to be working properly, then the next likely cause is the control card in the power supply. If you do not have a spare control card, but have other systems, you can use a known good control card from another power supply to determine if this is the problem. For more information on this or any other topic, please contact Fusion UV Systems Technical Service techservice@fusionuv.com.
A. All Fusion UV lamp systems include a RF detector to shut down the lamp system if microwave energy in excess of permissible levels is detected. This is usually caused by damage to the lamp unit such as a torn RF screen. During the start up sequence the system is designed to search for a functional RF detector and to automatically perform a functional test. 
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