Wilco looks ahead with lasers

Laser absorption technology has been used by Swiss company Wilco for the high precision automatic analysis of head space gas.

Developed specifically for pharmaceutical applications, the analysers are said to offer in-line non-destructive measurement of oxygen content, residual moisture and absolute pressure, guaranteeing 100% sterility.

A wavelength calibrated low energy laser beam is fired through the headspace of the container. The energy of the beam changes when increased levels of gas molecules are detected inside the container. Even cracks or pinholes under aluminium seals can be found. Each test result is compared with a reference value for acceptable containers.

The system can handle ampoules, vials, syringes and cartridges in clear and amber materials and in sizes from 1ml to 1000ml. In continuous operation, up to 800 containers/minute can be tested.

Advanced technology is also being used by the company for leak-testing any container filled entirely or partly with liquid, including vials, ampoules, bags, pouches and blow-fill-seal containers. The LFC method, which has patents pending worldwide, is not influenced by changes in temperature and humidity, nor do the liquids have to be conductive, the company says.

Any pressure differential changes in a vacuum or pressure environment are measured using two signals from highly sensitive sensors, making it possible to differentiate between large and micro leaks. Leaks down to 0.1µm can be detected and a throughput of up to 300 products/minute is possible.