What is mist and what is smoke is defined by the liquids involved in forming them, and their droplet size. Oil mist normally consists of a waterbased emulsion (coolant), where oil makes up 2-10% and the rest is water (used for lubrication and cooling purposes, respectively). Oil smoke is formed from neat oil, which does not contain any water. Therefore, the oil and the smoke that can be emitted from it are potential fire hazards. Neat oil and water emulsions are often referred to by a common term: MWF – metal working fluids.
Turning, milling, grinding, drilling, hardening and pressing are some of the most common procedures where oil mist and oil smoke are able to form. This usually happens when the flushing pressure is great and the emulsion is sprayed onto a tool or product moving or rotating rapidly. Oil smoke is formed in a similar way, by the same applications, but with heat as a major source.
In recent decades, increases in machine speed and productivity have lead to increases in oil mist and oil smoke particle fraction as well. The particles of the former tend to be bigger than those of the latter, making them easier to collect. Oil mist droplets are generally bigger than one micrometer in size, which in turn means that they are easier to collect than the particles emitted through oil smoke, which tend to be less than one micrometer in size.
The hazards posed by these substances are many and considerable. The machines containing the metal working fluids are not necessarily affected by them, but when these fluids are emitted as mist or smoke, they may accumulate in HVAC systems and/or result in dirty and sticky surfaces on ceilings, walls, floors, staircases and/or equipment. Moreover, they are often carcinogenic, and thus an immediate health hazard to those working inside the facility. They may also cause skin-related and respiratory problems. In addition, oil mist emissions may cause pools of water, in which dirt and bacteria may accumulate, to form on floors and machines.
In order to appropriately clean the air of the dangerous particles, one must install an efficient oil mist/oil smoke collector with an equally efficient filter medium. Collecting the particles is in many ways the less complicated part of the operation (although many collectors still underperform when doing so). The greater challenge lies rather with not having your filter instantly clogging up from the particles it collects. Without proper drainage, many filters would be full within only a few hours.
Drainage, thus the ability of a fluid (or solid) to enter and exit the filter medium, is dependent on a variety of factors, such as the density of both the fluid and the filter medium, air velocity, fiber length distribution and fiber density distribution. In the FibreDrain filters, the tiny oil droplets are collected by layers of fibers. The filters have a zigzag-patterned, wavelike design in order to increase the surface area and the potential for particle absorption. This design also contributes to a decrease in air velocity through the filter, which in turn makes more particles attach to the fibers. Due to the surface tension of the fiber threads, the droplets stay attached to the fibers, where they coalesce with other droplets. Coarse fibers, such as the ones used in FibreDrain, have superior drainage properties compared to finer fibers. While very good at collecting the droplets, finer fibers will not be able to keep them from falling off, though a more coarse type of fibers will.
Nederman’s FibreDrain oil mist and oil smoke collectors have been developed to ensure high filtration efficiency and a long filter life even at high oil mist/oil smoke concentrations during extensive periods of operation. The filters usually last for years, and require very little maintenance throughout that time. FibreDrain has proven to be especially useful in the automotive and aerospace manufacturing industries, where oil mist and oil smoke are prevalent and other solutions often fall short of providing adequate filtration.
The modular design of the FibreDrain filters means that they can be applied and expanded in a wide variety of ways, depending on the size of the industrial process or a particular machine, for example. They can be placed at individual work stations, or concentrated as a main filtration hub. The size of the filter is determined by the amount of air passing from the machine through the unit (in cubic meters per hour), not the concentration of particles. It is, however, possible to make certain adaptations to the filter depending on the concentration of hazardous particles – a unique feature of the FibreDrain oil mist and oil smoke collector.
With the addition of Nederman Insight, operators will be informed about filter exchanges and possible maintenance needs well in advance. This is likely to facilitate the work process even further, and create a system where both filtration itself as well as its maintenance may be carried out with ease and efficiency.
You can read more about FibreDrain here. Feel free to contact me if you have any questions about oil mist and oil smoke filtration, and make sure to read my upcoming article on how you can increase the safety of your neat oil applications.
We have extensive experience of various challenges in the different industries and our experts are very skilled, helpful and professional. With us, you can feel secure that we take care of you and your needs. You are always welcome to contact us regardless if you have a short question or a more complex and complicated one. A warm welcome to Nederman.
Contact us here
