The right plain bearings for air diffusers & sleepless nights in Shanghai

John Ji | September 18, 2020

Dry topics are best conveyed with less dry stories. Recently, a colleague from international sales told me about his visit to our branch in China. According to his narrative, the first night in the hotel was not only marked by jet lag but also particularly by an annoying squeaking. Quiet, but just loud enough to rob sleep and difficult to locate. And for hours! Admittedly, the tension of the original narrative is difficult to reproduce in pure text. Therefore, unfortunately, the unspectacular finale of this thriller, which in its implications only partially rocks the hotel industry, is disappointing. But how does this topic and plain bearings for air diffusers fit together?

… Are you familiar with these air diffusers that bring cool airflow into rooms when outside temperatures are too high? Did you know that they sometimes move in order to distribute and regulate said airflow? Here it comes: they move with plain bearings!

You guessed it: the reason for my colleague’s sleepless night was indeed here. The plain bearings in the air diffusers squeaked!

You can avoid squeaking and failures with the right plain bearing for air diffusers

As unspectacular as this plain bearing application may appear at first glance, the devil is in the detail. Components such as these air diffuser flaps are supposed to last forever, if possible. After all, which hotel operator can afford to have a technician regularly running through all 60,000 rooms, who has to replace dozens of bearings in the air diffusers. In the case of simple air diffusers for air conditioning units, the risk to mankind is limited. But there are also really critical systems. In case of fire, special ventilation systems – so-called fire dampers – regulate the oxygen supply and keep escape routes smoke-free for as long as possible. The functionality and reliability of plain bearings is essential here for survival.

Self-extinguishing plastic bearings made of iglidur® GV0 (Source: igus GmbH)

Lubricated plain bearings can be a problem in these applications. In practice, we have come across plain bearings made of sintered bronze, for example. These are normally “maintenance-free“. The pore structure of the bearing “retains” the lubrication and releases it when the bearing moves. However, in ventilation systems with insufficiently sealed bearing points, the bearings partially dry out. The result: seizing of bearings.

In general, the often relatively inaccurately punched sheets are a challenge for many plain bearings. Added to this is the high air humidity, depending on the place of use, which leads to corrosion in metallic plain bearings.

Plain bearings made of iglidur® polymers offer many advantages here. Lubrication in the form of “solid lubricants” is firmly embedded in the material. The coefficient of friction and wear behaviour remain the same for years and are therefore predictable and reliable. With these specifications, iglidur® represents a clean, reliable and above all – also in the interest of the noise-plagued hotel traveller – quiet solution as plain bearings for air diffusers and fire dampers. Furthermore, there are additional iglidur® plain bearing materials with self-extinguishing specifications according to UL V0 especially for use in fire dampers.

We would be happy to assist you!

Do you need support in the selection and design of your plain bearings? igus has been manufacturing plain bearings from high-performance polymers optimised for wear and coefficient of friction since 1964. More than 200,000 customers from the most diverse industries count on iglidur® plain bearings worldwide. Our application consultants will assist you by phone, e-mail, live chat, video call or at your site to solve wear problems.

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