## 2 Materials and Methods  
For the experiment of measuring the thickness of the oil layer by applying the oil mist to the interior of the 6 m long thin tubes, the following components were used: oil \"Anticorid DFT 2001\"; oil mist \"SMC LMV210-35\"; \"Apollo 50\" compressor (air receiver 50 L, output power 1.5 kW, supplied air volume 158 L/min) with pressure regulator; calibrated weight \"A&D\" TSQ 128/95-133 model, d: 0.01 g, e: 0.02 g, carrying capacity: 200 g; accessories for working with compressed air; length gauge; and cutting knife. The overall view of the application environment in the state of preparation before application and measurement is shown in Figure 1. A pair of steel tubes served as a solid support for Mirelon application pipes that are soft and flexible. Chemical characterization of the oil applied in experimental measurements \"Anticorrid DFT 2001\", is specified in the product Safety Data Sheet, according to EU Directive no. 1907/2006, Article 31, Act No. 163/2001 and Decree 515/2001 as a mixture of deeply refined petroleum oils, volatile hydrocarbons and corrosive additives. The oil also contains the following hazardous substances:  
* hydrocarbon dearomatized solvent, denoted: Xn, R465, 66 with the concentration of: 50-99%;
* Na-sulfonate, denoted: R53 with the concentration of: 1.2-2.4%;
* solvent naphtha labeled: Xn, Xi, N, R10, 37, 51/53, 65, 66, 67 with the concentration of: 0.1-1%. The oil parameters according to the Product Card and used in the experimental verification are as follows:  
* density: 830 kg/m\({}^{3}\), at the temperature of 25 \({}^{\circ}\)C, in compliance with DIN 51 757 standard;
* kinematic viscosity: 4.6 mm\({}^{2}\)/s, at the temperature of 20 \({}^{\circ}\)C, in compliance with DIN 51 562 standard;
* vapor pressure: 1 mbar, at the temperature of 20 \({}^{\circ}\)C;
* solubility in water, or miscibility with water: not miscible. In course of the experimental measurement itself, the following conditions were measured or estimated:  
* date of measurement: 30. 12. 2016;
* temperature in the experimental laboratory: 10 \({}^{\circ}\)C (\(\pm\)0.2 \({}^{\circ}\)C);  
Figure 1: Application environment for experimental coating of inner surface of tubes by dispersion oil fraction and equipment. * working pressure in the compressor air receiver at the start of oil dispersion application: 8 bar;
* working pressure in the application pistol during the blowing of the oil dispersion: 6 bar;
* the estimated flow rate of the air mix and the dispersed oil fraction in free space: 3 m/s;
* cutting precision of one-meter sections with a length of \(\pm 1\) mm. Figure 2 shows the course of application of the oil layer onto the inner surface of the tubes. The application lasted 15 s and Fuchs \"Anticorid DFT 2001\" oil was applied to 6-m long Mirelone tubes. Following the application of the oil through the dispersion oil fraction, the Mirelone tube was divided into one-meter sections, each weighed on the certified scale, Figure 3. First, only a Mirelone tube marked as plain was weighed. Then, the weighing was repeated, this time recording the weight of the tube with oil. The resulting net oil film weight was calculated by simple subtraction. Figure 4 shows a schematically illustrated pneumatic diagram of device alignment in experimental measurement. Manometer 1 is coupled with the pressure regulator and indicates the pressure set thereon when the latter is active. The manually operated hand valve is a hose of 10 mm in width and 5 m in length. Measurement scenario for one sample (1-m long tube) was as follows:  
1. The pressure regulator was set at 8 bar. 2. The compressor, which pressurized the air at a pressure of 8 bar into a 50 L vessel, was switched on. 3. Six pieces of dry, one meter long application pipes were weighed. Their dry weights were recorded in the metering protocol for later processing. 4. One meter long dry pipes were connected in five places to a total length of six meters.