【正文】 pneumatic system incorporates the following ponents and devices: (1)Air supply devices: They include pressure generation devices, air regeneration and storing devices, F. R. L. (air filter, pressure reducing valve and oil mist lubricator) bination, etc. It provides qualified pressed air for pneumatic systems. (2)Actuators: They convert the pressed air pressure into mechanical energy, such as air cylinders and air motors. (3)Control elements: They are used to control the pressure, flow rate and moving direction for the ponents, such as valves. (4)Pneumatic attachments: They incorporate the ponents which are used to cool, silence, purify, and lubricate pressed air and those to joint each ponent. Air Supply Devices Air supply devices are used to provide pressed air for pneumatic systems. An air supply device is an important part of a pneumatic system, which supplies qualified pressed air (with a certain lever of pressure, flow rate and purification) for the pneumatic system. Generally, for the delivery surpasses or equals 6 12m179。/min, a pressed air station is needed. But for the delivery less than 6 12m179。 Cooler: cool pressed air。 Oil and water separator: remove gross solid and liquid particulates。 settling chamber for particulates。 Air dryer: further reduce water and oil vapour content。 (2) According to structures (3) According to output pressures: Low pressure ( ), medium pressure ( 10MPa), high pressure (10 100MPa), super high pressure (100MPa). (4)According to output flow rates(delivery): Mini (1m179。/min), medium (10 100 m179。/min). Purification and storing devices and equipments for pressed air Normally, purification equipments for pressed air involve: cooler, a moisture separator, a receiver and an air dryer. Cooler:cooler is usually set at the outlet port of the pressor and serves as a heat exchanger to cool pressed air after leaving the pressor. Cooling can reduce an air temperature of 120 150176。C. Coolers can be further classified based on their arrangement: coil tubular type, series tubular type, thermosyphon system and tube drive type. There are two types of cooling: water cooling and air cooling. Moisture separator: it is used to separate the impurities such as condensed water and oil stain from the pressed air to gain an initial purified pressed air. When pressed air enters the separator, its flow rate and velocity will change sharply and the impurities with a higher density initially purified. The configurations of separators incorporate: ring revolving type, strike and return type, centrifugal rotary type, waterbath type, etc. This is a strike and return type moisture separator. When the pressed air enters the separator, it strikes against the baffle and turns sharply before falling down. When air falls down, it again strikes the case bottom and then rises up. The water droplets and oil are then separated from the pressed air by the centrifugal force produced by the sharp turning action. Receiver: it is used to store a certain amount of pressed air, reduce its pressure fluctuation and provide gas continuously and stably. There are two types of receivers: horizontal and vertical. Vertical type receivers are more often adopted to save room. Nowadays, the arrangement with the bination of cooler, moisture separator and receiver has found many applications. Air dryer:the pressed air after having been purified and treated by the cooler, 大連交通大學(xué)信息工程 學(xué)院 2020 屆本科生畢業(yè)設(shè)計（論文）外文翻譯 3 moisture separator and receiver can meet the requirements of general pneumatic systems. But for other precise devices such as precise machines and meters, the pressed air must be further purified or treated. Air dryers have the function of further removing water vapour, oil mist and other particle impurities with mini diameter. Methods of air drying incorporate mechanical, centrifugal force, refrigeration, adsorption, etc. F. R. L. bination F. R. L. bination is short for the bination of an air filter, a pressure reducing valve and an oil mist lubricator. First es the air filter (secondary filter), followed by the pressure reducing valve and the oil mist lubricator is set behind (see from the air inlet direction). F. R. L. bination supplies better quality pressed air for pneumatic ponents or systems. Air filter: An air filer is used to remove dust, impurities, oil stain and separate water vapour from the pressed air. As pressed air passes the inlet port and enters the filter section, it passes through the directional louvers forcing it into a whirling flow pattern. Liquid particles and heavy solid are thrown against the inside wall of the bowl by centrifugal force. The liquid then runs to the bottom of the bowl where it is either removed by the automatic drain assembly or by the manual drain the baffle maintains a “quite zone” in the lower portion of the bowl to prevent air turbulence from picking up the liquid and returning it to the air stream. The air then passes through the filter element to remove solid contaminants. Oil mist lubricator: An oil mist lubr