1. The characteristics of mobile air compressors are:
(1) Mobile air compressors must be easy to move frequently, with variable working conditions and large load changes.
(2) Mobile air compressors are mostly heavy-load, medium-speed or low-speed transmissions, most of which require frequent starting and often bear impact loads;
(3) The outdoor environment is harsh and humid, with rock dust, coal dust and gas (the main component is methane), and some also have harmful sulfur-containing gases (sulfur dioxide, hydrogen sulfide). Therefore, many mobile air compressors have to encounter fire prevention, explosion prevention, and corrosion prevention problems;
(4) Outdoor mobile air compressors must be able to withstand wind, sun, rain, and climate changes such as hot summer and cold winter;
(5) Due to the small space, the machine is difficult to repair, so the mobile air compressor is required to be durable and easy to repair.
II. According to the characteristics of mobile air compressors, the following requirements are put forward for lubricating oil:
(1) The size and oil tank capacity of mobile air compressors are small, the amount of lubricating oil installed is also small, and the oil temperature is high during operation, which requires the lubricating oil to have good thermal stability and oxidation resistance.
(2) Because the outdoor environment is harsh, there are more coal dust, rock dust and water, and the lubricating oil is inevitably contaminated by these impurities, so the lubricating oil is required to have good anti-rust, anti-corrosion and anti-emulsification properties; it is required that when the lubricating oil is contaminated, its performance will not change too much, that is, the sensitivity to pollution should be small.
(3) The temperature of outdoor machinery varies greatly in winter and summer, and the temperature difference between day and night is also large in some areas. Therefore, the viscosity of the lubricating oil is required to change little with temperature. It is necessary to avoid that the viscosity of the oil becomes too low when the temperature is high, so that the lubricating film cannot be formed and the lubricating effect cannot be played. It is also necessary to avoid that the viscosity is too high when the temperature is low, so that starting and operation are difficult.
(4) For some mobile air compressors, especially those used in environments prone to fire and explosion accidents, it is required to use lubricants with good flame retardancy (flame retardant liquids), and flammable mineral oils cannot be used.
(5) The lubricant is required to have good adaptability to the seals to avoid damage to the seals.