Invisible protection against harsh weather on the high seas

However, halogen lamps are a lot less efficient than their LED-technology counterparts, converting up to 95% of the energy they consume into heat. At an ambient temperature of -40°C, halogen luminaire housings can reach temperatures of up to +60°C. The hotter the lamp gets, the more the air inside its housing expands and the greater the internal pressure that causes air to escape through the seal. As soon as the lamp is switched off, the air cools – rapidly in some cases, depending on the outside temperature.

This temperature change causes a vacuum inside the luminaire housing. This pressure can easily reach values of up to -160mbar, which is enough to prevent maintenance technicians from being able to open the luminaire by hand. The vacuum also sucks air and moisture into the housing through the seal. Over time, they become so fatigued that they let water, dust and other particulates in, which can lead to corrosion that can destroy the socket of the floodlight.

To solve this problem and extend the life-cycle of its halogen lamps even under harsh weather conditions on the high seas, lighting specialist WE-EF integrates a pressure equalisation solution in their housing design. “We received several complaints and were faced with having to decide between discontinuing the product line and modernising the technology to make it state of the art,” said Peter Oetjens, Head of Engineering, WE-EF. “Given the great success of the vents we’ve integrated into all our newer products, selecting a venting membrane made by Gore was the obvious next step for us.”

The vent had to be easy to integrate into the existing luminaire design and able to permanently withstand the large temperature differences and extreme weather conditions to which the luminaire would be subjected. A glue-bonded structure was ruled out since the existing luminaire design would not protect it from the elements, allowing hail and other environmental conditions to quickly destroy the membrane.

A more reliable solution was required - pressure equalisation elements which could be screwed in. The sensitive, microporous venting membrane made from ePTFE is permanently protected by a robust polyamide housing.

How the membrane is attached is a crucial factor in the success of the product. Oetjens explained: “The Gore membrane is attached inside the polyamide housing in such a way that it cannot detach. We’re very satisfied with this pressure equalisation solution and we haven’t received any more product returns.“

In a vented housing, rapid cooling causes no pressure differential because the vent allows the pressure to equalise easily. Without a vent, the negative pressure can cause dirt and moisture ingress via the seal.

“Gore Screw-in Vents offer the ideal blend of cost efficiency and robustness to meet our requirements for this application,” added Oetjens. “We didn’t consider using products made by anyone else because, given the specified flow rates, differential-pressure data and IP classes, we felt there was too great a risk that the existing problem would not be solved. But we already had very good results using Gore Screw-in Vents in other exterior luminaires. Gore’s venting solution not only ensures the longevity of the halogen lamp, but is also the key to continuing our floodlight business.”