Quartz Sleeve Wiper Systems in Aquaculture - Tech Talk 135
Over the years, there has been a considerable amount of debate regarding the use and benefits of quartz sleeve wiping systems in UV Disinfection equipment. Our position on this subject is that wiper systems are typically not necessary in Aquatic Life Support applications that utilize Low-Pressure Lamp UV Disinfection systems. They essentially only serve to add a higher level of cost, maintenance, and complexity to this equipment with very little benefit.
In an attempt to clarify the original intended purpose of wiper systems, and to qualify what the specification criteria should be, we would like to point out the situations that affect/require these mechanisms.
- ORIGINAL PURPOSE: Quartz sleeve wipers were originally intended for waste water treatment systems that are routinely subjected to high levels of organic fouling during off line usage (such as when the UV is actually off but left submerged in the effluent water). The wiper system is used under these conditions to remove any bio-floculant that may have accumulated on the sleeves (as a result of this non-use period) prior to restarting.
- TYPE OF UV LAMP: The type of UV lamp utilized will influence whether a wiper system is required. For instance, Low-Pressure UV Lamps (in all forms) do not require wiper systems due to their low heat level. As a result of this low heat level, the quartz sleeves are not prone to heat induced fouling. On the other hand, Medium-Pressure Lamp based systems must include a wiping system to maintain the quartz sleeves in a reasonable state of use due to the extreme heat level at which these lamps operate. The heat that is produced by these lamps literally bakes the deposits onto the sleeve’s surface, reducing its ability to effectively transmit the UV-C radiation into the surrounding liquid that has yet to be treated.
- LIMITATIONS: Quartz sleeve wiper systems will not remove scaling on the sleeve caused by mineral deposits (i.e. calcium deposits). These types of deposits can be removed only by chemical means such as an acid bath.
- CONCLUSION:UV wiping systems are typically not necessary in Low-Pressure Lamp UV Disinfection equipment installations in Aquatic Life Support applications. They are typically used on a 24/7 basis of operation with no off-line usage, as is the case in waste water treatment systems. Wipers essentially only serve to add a higher level of cost, maintenance, and complexity to this equipment with little benefit.