The external UV unit is used to disinfect water-bearing systems by means of UV radiation. The water to be treated is exposed to intensive radiation by UV-C light in the UVE reactor. The system is installed externally on the unit’s operating side.
The installed recirculating pump ensures that the system water is constantly recirculated, which reinforces the UV contact frequency and hence safety from renewed germ formation.
Application areas for UV reactors:
The external UV reactor system is used for sterilisation of a wide range of applications. This system can be used to disinfect water-bearing systems in general. At Lavair, it is mainly used to sterilise the recirculating water of the air humidifiers/ air washers, ensuring that, if used correctly, no unacceptable bacterial growth can occur.
The external UV sterilisation unit consists of a stainless steel UV reactor, a control monitor and either a simple UV sensor with a pressure switch in the water-bearing piping or a combined UV and temperature sensor. The UV-C lamp is located in an empty quartz tube inside the reactor. The empty tube is sealed watertight by means of an O-ring.
There is a sampling point upstream of the reactor’s inlet and downstream of its outlet. A recirculating pump is used to suck the water from the tank and pump it through the reactor.
The freshly sterilised water is then channelled back to the original tank.
The pump is normally a 400 V industrial pump (0.75kW), which is additionally protected via the overall system’s dry run protection and is supplied with voltage from the external control cabinet. The UV-C’s service life is approx. 8,000-9,000 hours, depending on model. The control monitor constantly monitors the UV radiation strength as well as the lamp’s runtime. If the maximum runtime is exceeded or if the radiation intensity falls below the minimum requirement (approx. 60%), both an optical and an acoustic alarm signal are output.
Reduced radiation intensity, which causes a fault message before the end of life, is often due to contamination of the UV sensor or the empty pipe.