Ultra Violet Condensation Test Apparatus

The SA UVCON is a device for exposing materials to alternate cycles of Florescent ultra-violet light & condensation. The Unit provides a screening test for coatings, plastics, pigments & the like which may be specifically affected by the UV portion of sunlight spectrum alongwith moisture penetration. Screeing test of this type can give early indications as to how the material must be expected to perform in a natural outdoor environment.

The SA UVCON uses it's light source eight FS-40 Flourescent Sun Lamps. These Lamps are mounted in two banks of four each, are rich in Ultra-Violet energy between 280-350 watts at an operating voltage of 220 volts. An electrical discharge within the tube generates Ultra-violet energy at 254 Nanometers which excites the Phosphor coating causing it to flouresce & radiate approx. 85% of the lamp's energy between 280-350 Nanometers. In the natural sunlight spectrum below 350 NM, accounts for only about 3% of the total radiant energy. The UV below 310 NM producted by these lamps at sample face (50mm from the lamp) is several times greater than that of natural sunlight & is the principal cause for acceleration in a test.

The fluorescent sun lamp produce virtually no significant visible or infra-red energy. Lamp Intensity normally deteriorates by about 20% during 1600 hours of useful life & the lamps are changed on rotation basis. Every 400 hours a new Lamp is installed in each bank of 4. This method ensures reasonably uniform radiation at the sample face. The condensation of SA UVCON is produced by heating water in a stainless steel sump of the Unit with an Electric Immersion heater. Natural convection causes saturated air to move up across the face of the exposed panels. Mounted in their rack these panels act as exterior walls of the Test Chamber. Ambient room air moving across the backs of the Test Panels causes a temperature differential & dew droplets condense on the panel face. The condensation cycle allows water to form naturally free of mechanical & thermal shock with maximum purity. During a typical 24 hour cycle, the UVCON uses about 8 litres of water.

The UVCON has two specimen racks, 330 mm high &1154 mm wide, each facing one bank of lights. Can accommodate a total of 20 rack panels, approximately 100 mm x 300 mm.

Controls

A Programme Timer automatically controls the UV & Condensation cycles of the UVCON & programming. Each can one Programme Cycle typically 24 hours of UV followed by four hours of condensation.

Temperature is measured & controlled by a solid state circuit. A PT-100 Sensor is mounted in a black aluminium panel on the specimen rack. The temperature is set by the Operator using Digital Thumb wheel switches & monitored by a readout Digital Panel Meter on the Control Panel. The UVCON is normally operated between 50 & 70 plus minus 3 degrees celsius. During the Ultra-violet exposure & between 40 & 50 plus minus 3 degrees celsius during condensation exposure.