What is ultraviolet (UV) light?

Ultraviolet light is a particular portion of the light spectrum, typically considered to be in the wavelength range from 200 nm (nanometers) to 400 nm. Light in this spectral range has many important uses including water purification, semiconductor lithography, sun tanning and, of course, adhesive curing. Since ultraviolet light falls below the visible portion of the light spectrum, we cannot see pure UV light. Special equipment—a radiometer—is required to measure the intensity of UV light. The intensity of light falling on a surface is measured in milliwatts per square centimeter (mW/cm2), or power (mW) per unit area (cm2).

UV Lamp Operating Parameters

Western Quartz recommends an operating ultraviolet (UV) lamp wall temperature range between 600° C and 800° C. Higher temperatures can cause devitrification and/or distortion of the quartz envelope resulting in short lamp life. Temperatures below 650° C can cause condensation of the mercury resulting in an unstable environment and premature darkening of the lamp body. The end seals have a temperature limitation starting at 250° C and above as molybdenum oxidizes at this temperature and higher. Temperatures higher than this can result in subsequent seal failures. Therefore, we recommend keeping the end-seal and fitting areas at 200° C or lower, to eliminate risk of oxidation with subsequent seal failures.

Proper Handling & Maintenance Of UV Lamps

All Western Quartz ultraviolet (UV) lamps are wiped down carefully before their packaging and shipment. If handled carefully, (i.e. no fingerprints on body of lamps), they are ready for use when unpacked. If the lamps are touched with bare hands, they should be carefully wiped down with a 'lint free' towel slightly dampened with deionized water or denatured alcohol. Ultraviolet (UV) Lamps and reflectors should be subsequently cleaned when necessary, particularly if there is any misting of ultraviolet (UV) curable materials in the area. Premature devitrification and reduced lamp performance may occur if lamps are improperly run in a contaminated environment.

A lamps life depends on many factors such as the number of cold starts, operating time per start, electrical and thermal operating parameters and proper handling. All continuous running Western Quartz mercury lamps are warranted against manufacturing defects when used under proper conditions. Hourly coverage is also applied with the vast majority of our mercury curing lamps.

Safety Precautions When Working With UV Lamps

Mercury vapor lamps emit ultraviolet radiation which is harmful to eyes and skin. Avoid looking at a lamp in operation. Suitable eye and skin protection should be employed when lamps are in operation. The equipments reflected radiation from a UV lamp is also harmful to eyes and skin. Clear fused quartz is used for the standard ultraviolet curing lamp and will generate ozone during operation. When using this type of lamp their should be adequately ventilated to comply with OSHA regulations. While ozone is unstable, it will be at a safe level by the time it leaves the equipment’s exhaust stack.