UV Sterilizers with UV Intensity Monitors
UV sterilizers featuring the added protection of UV dose monitoring - recommended for applications with significant known microbiological risks
Many of our UV sterilizers are equipped with a 254nm wavelength UV intensity monitor which continuously analyzes the intensity of the UV rays to ensure that the water is receiving a safe UV dose. The UV intensity sensor is located on the side of the UV sterilization chamber and will detect all potential causes of a reduction in UV intensity, including a decline in the lamp's output of germicidal spectrum UV-C rays, a build-up of minerals, stains, or debris on the UV sleeve, a decline in the UV transmittance qualities of the water due to color, turbidity or increase in UV-absorbing organics (failure of pre-treatment), or a decline in UV output due to excessive water temperature. The sensor functions much like a miniature solar panel; a silicon-carbide photodiode converts UV light into electrical energy. The sensor measures the energy and translates it into an equivalent intensity reading. The intensity sensors are factory-calibrated and are not field adjustable. The sensor is resistant to degradation and drift caused by exposure to UV light. In the event that the UV intensity monitor recognizes a decline in UV intensity that would result in inadequate disinfection, an alarm will sound. If an optional emergency solenoid shut-off valve is installed, the alarm would trigger the solenoid valve to close, thereby preventing water flow until the problem is resolved.
The use of a model with a UV intensity monitor is generally recommended where a known E.coli or other serious problem is present or the feed water parameters may cause problems with UV tramsmittance from time to time (sediment from rain event, iron or hard water scale build-up on the UV sleeve, etc.).
It is important to note that UV intensity monitors are sensitive and will detect a wide range of potential problems related to feed water quality. If proper pre-treatment is not undertaken, frequent alarms can be expected if the UV transmittance drops below 75% or if proper sleeve maintenance is not done. If your UVT is known to be less than 85% or your source water is coloured or cloudy, please call us for pre-treatment and sizing assistance (toll free 1-866-376-2690).
* Please note that the flow rate capacities specified above are based on a UV dose of 40 mJ/cm2 at 95% UV transmittance (UVT) unless otherwise noted (NSF-55, Class A Validated models will have flow capacity noted at 40 mJ/cm2 at 75% UVT for instance). UV transmittance is a measure of the clarity of your water and the ability to pass UV light through it. 95% UVT should be considered rather ideal. When using a UV sterilizer with a UV intensity monitor, it is very important to ensure that the feed water has a UVT level of at least 75%, preferrably higher than 85%. Proper pre-treatment can ensure this. Feeding water with a low UV transmittance will result in frequent UV alarms as the system will detect that the UV dose is not satisfactory to meet disinfection goals. If your UVT is known to be less than 85% or your source water is coloured or cloudy, please call us for pre-treatment and sizing assistance (toll free 1-866-376-2690).
