The main physical properties of air for pneumatic hydraulic presses
The physical and chemical properties of air in pneumatic punching machine include density, viscosity, humidity, compressibility and expansion. The servo hot press drive system mainly has two types: pump direct drive and pump - accumulator drive. The pump directly drives the pump of the driving system to provide high pressure working liquid to the hydraulic cylinder. The valve is used to change the direction of the liquid supply. The relief valve is used to adjust the limited pressure of the system and play the role of safe overflow. Single action hydraulic press liquid in a closed container when the transfer of pressure is following PASCAL's law. The hydraulic transmission system of four-column hydraulic press is composed of power mechanism, control mechanism, executive mechanism, auxiliary mechanism and working medium. The power mechanism usually adopts the oil pump as the power mechanism, which is generally the product type oil pump. The principle of composite hydraulic press is the use of PASCAL's law made of the use of liquid pressure drive machinery, there are many kinds. Of course, the use is varied according to the need. Such as according to the transfer pressure of the type of liquid, there are two types of hydraulic press and hydraulic press. 4000 ton hydraulic press A machine that uses liquid as the working medium to transfer energy to achieve various processes. Hydraulic press in addition to forging forming, can also be used for correcting, pressing, packing, pressing block and pressing plate. Hydraulic press includes hydraulic press and oil press. The water-based liquid as the working medium is called hydraulic press, and the oil as the working medium is called hydraulic press.
Density The mass of air in a unit volume, called air density, is denoted by p.
The nature of friction resistance generated by the movement of viscous air is called viscosity, viscosity is usually expressed by motion viscosity, the influence of pressure on air viscosity is small, usually can be ignored. The viscosity of air increases with the increase of temperature, mainly due to the increase of temperature. After the increase of temperature, the movement of molecules in the air is intensified, which leads to the increase of intermolecular collisions. Wet air comes in two forms: dry air and wet air. Air containing water vapor is called wet air. Air containing water vapor is called dry air. Air without water vapor is called dry air. The Qigong system uses dry air as the working medium. The water content in wet air is expressed in terms of humidity and water content. The mass of water vapor contained in a unit volume of wet air is called the humidity of wet air. The ratio of humidity and saturation humidity at a certain temperature and pressure is called the relative humidity at the temperature. The relative humidity at the temperature is represented by c. In pneumatic technology, it is stipulated that the relative humidity of the air entering the control element should be less than 95% of the mass of 0 unit mass of dry air mixed with water vapor, called the mass moisture content, represented by d.
Pneumatic pressure can be compressed and expandable air, gas molecular spacing is large, cohesion is small, pneumatic pressure makes air pressure and temperature change, the volume is easy to change. The property that the volume of air decreases with increasing pressure is called compressibility of gases. The property that the volume of air increases with the increase of temperature is called gas expansibility.
