FRANKE-Filter FAQs

An Oil Mist Separator is the technical term for filter systems that are used where power generating engines or turbines operate, e.g. in power plants. To ensure trouble-free operation, the bearings of the respective rotary machines are equipped with so-called lubricating oil. During operation, this friction causes great heat, which is responsible for the formation of very fine oil mist. In addition, the rotation causes strong turbulences. The resulting oil mist is often released unfiltered into the atmosphere and causes oil deposits in halls and on machines.

Summarily, Oil Mist Separators are required to extract the oil mist produced and prevent leaks in the bearings by means of an individually adjustable vacuum. At the same time, an Oil Mist Eliminator helps to comply with almost all applicable environmental regulations and thus contributes to environmental protection.

The oil contaminated air is sucked into the filter system through a side channel vacuum pump, which creates a negative pressure in the lubricating oil system, via an intake line. This negative pressure is necessary and can be individually adjusted to the given requirements by means of the regulating valve which is part of the basic equipment. Inside the filter housing, the air is filtered through several highly efficient microfibre filter cartridges. These filter elements ensure that the fine oil droplets on the microfibres form larger drops and run downwards due to gravity. The oil collected at the bottom of the filter is returned to the lubricating oil tank in a continuous flow via the return line and eventually can be reused.

A basic distinction can be made between electrostatic, centrifugal and coalescence separators. In electrostatic filtration, the oil particles are charged in the ionisation zone before they are deposited onto the collector plates. In the centrifugal separator, a direct effect of gravity and centrifugal force is produced on the oil particles. A drum rotor sucks in the gas flow and deflects it in order for the particles to be thrown against the wall and get separated. The coalescence separator is characterized by excellent filtration efficiency. The raw gas is sucked in by a side channel vacuum pump and the aerosols are absorbed into the filter material. At a certain saturation of the filter medium, the individual droplets merge into one larger drop and flow back into the lubricating oil tank. Oil Mist Separators from FRANKE-Filter filter exclusively according to the coalescing principle.

The application areas of Oil Mist Separators range from lube oil tanks of gas, industrial gas, steam and water turbines to compressors, gas and diesel engines, vacuum pumps and generators. The places of operation range from power plants, refineries and LNG terminals to direct turbine manufacturers.

Ultimately, wherever rotary machines are lubricated with oil, the use of Oil Mist Separators is possible, useful and necessary.

Oil mist is often generated by all types of rotary machines. In order to guarantee smooth operation, the machine bearings are lubricated. During operation, friction generates a great deal of heat, which is responsible for the formation of fine oil particles. Therefore, the problem with oil mist is one that many operators face. If the resulting oil mist is not extracted, it can lead to dirty work halls and equipment resulting in an increased safety and fire risk. If the oil mist escapes unfiltered into the atmosphere, the environment also suffers long-term damage from the polluted air. With our efficient Oil Mist Eliminators we want to prevent these risks and protect the environment.

In most cases oil mist is quickly detectable. Due to inefficient extraction and filtration of oil mist, which takes place within the oil module space, excessive contamination is caused by oil deposits in the vicinity of the lube oil tank. It is mostly possible to determine how high the oil mist contamination is by taking a quick look at the bearings of you rotary machine. If you detect a strong smell or a large accumulation of oil residues, action should be taken as soon as possible in order not to endanger the safety of employees and to ensure that the machine runs smoothly. Oil stains under the outlet connection indicate if the oil mist is led outside.

If the oil mist produced is not extracted, it can result in dirty work halls and equipment and therefore pose an increased safety risk. The loss of lubricating oil due to inefficient filtration of oil mist is also a problem leading to long-term consequences. Depending on the oil contamination on the turbine, up to 25 liters of lubricating oil per day can escape from the oil tank. If the oil mist further escapes unfiltered into the atmosphere, the environment suffers long-term and lasting damage from the polluted air. With our Oil Mist Separators, we have set ourselves the goal of preventing the existing risks and making a significant contribution to environmental protection.

The appropriate value for the vacuum is specified by the manufacturer of your rotary equipment. Experience shows that this is usually between -3 and -10 mbar. To make sure, please refer to the requirements and specifications of your original manufacturer. In general, a minimum vacuum is sufficient for the highly efficient extraction of oil mist - true to the motto: as little as possible, but as much as necessary.

FRANKE-Filter uses specially developed microfibre filter cartridges for the filtration process. These filter elements guarantee a filtration efficiency of 99.9% at a particle size of the oil mist of 0.1 µm. Furthermore, the microfiber filter elements ensure a maintenance-free operating time of up to 30,000 operating hours - this corresponds to a service life of the filter elements of 2-5 years.

Oil Mist Separators from FRANKE-Filter are in operation worldwide. Please feel free to contact us directly by writing or calling us or get in touch with one of our worldwide partners.

Nowadays, there are regulations on compliance with environmental guidelines in almost every country. In Germany, the Technical Instructions on Air Quality Control (called TA-Luft) is a general administrative regulation that applies to the entire Federal Republic of Germany. It contains nationwide, binding requirements for systems, which must be met by the system operators. According to the current version, old plants need to be updated by 2007 and reduce their pollutant emissions in accordance with the TA-Luft requirements (less than 20mg/m³). Oil Mist Separators from FRANKE-Filter meet these requirements by allowing a residual oil content after filtration of only 1-5mg/m³.