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Common knowledge for air compressor installation 1. Selection of the installation location The selection of the location where an air compressor will be installed is something that is often overlooked by workers; frequently, after purchasing the compressor, a random spot is chosen, piping is installed, and the compressor is put into use without any prior planning. Little did they know that such a hasty approach would lead to problems with the air compressor in the future, such as difficult repairs and poor air quality; therefore, an appropriate installation location is a prerequisite for the proper use of the air compressor system. (1) Choose a spacious location with good natural lighting to provide the necessary space and illumination for operation, maintenance, and repair. (2) Choose a location with low air humidity, little dust, fresh air, and good ventilation, avoiding environments with water mist, acid mist, oil mist, as well as high levels of dust and fibers. (3) In accordance with the requirements of GB50029–2003 \"Code for Design of Compressed Air Stations\", the heating temperature in the machine room of a compressed air station should not be lower than 15°C, while the temperature in the machine room during off-hours must not be lower than 5°C. (4) When the air compressor intake or the cooling air intake of the unit is located indoors, the indoor ambient temperature should not exceed 40°C. (5) If the factory environment is poor and there is a lot of dust, pre-filtering equipment must be installed to ensure the service life of the components in the air compressor system. (6) In compressed air stations where the exhaust volume of a single unit is 20 m3/min or more, and the total installed capacity is 60 m3/min or more, it is advisable to provide lifting equipment for maintenance, with its lifting capacity to be determined based on the heaviest component of the air compressor unit. (7) Reserve passages and maintenance space; in accordance with the requirements of GB50029–2003 \"Code for Design of Compressed Air Stations\", the width of the passage between the air compressor unit and the wall should be 0.8 to 1.5 meters, depending on the exhaust volume. 2. Precautions for compressed air pipeline installation (1) When installing the main pipelines, they should have a slope of 1° to 2° to facilitate the drainage of condensate from the pipelines, as shown in Figures 1 and 2. (2) The pressure drop in the piping system must not exceed 5% of the pressure at which the air compressor operates; therefore, it is advisable to use pipes with a diameter larger than the value calculated based on the design parameters. The formula for calculating the pipe diameter is as follows: d = mm = mm. Here, Q PRESS is the flow rate of compressed air in the pipeline, in m3/min; V is the flow velocity of compressed air in the pipeline, in m/s; Q SELF is the value indicated on the air compressor’s nameplate, in m3/min; and p DISCH is the absolute pressure of the air discharged by the compressor, in bars (equal to the compressor’s discharge pressure plus 1 atmosphere). (3) Branch pipes must be connected to the top of the main pipe in order to prevent condensation water from flowing into the working machinery or back into the air compressor. (4) The diameter of the pipeline should not be changed arbitrarily; a reducer should be used. If no reducer is used, turbulence will occur at the joints, and such turbulence leads to a significant pressure drop as well as having an adverse effect on the lifespan of the pipeline. (5) If there are purification and buffering devices such as air storage tanks and dryers after the air compressor, the ideal piping sequence should be air compressor + air storage tank + dryer. The gas storage tank can filter out some of the condensed water, and it also serves to lower the temperature of the gas. Reintroducing compressed air at a lower temperature and with less moisture content into the dryer can reduce the load on the dryer. (6) If a large amount of air is used over a short period of time, it is advisable to install an additional air storage tank as a buffer; this reduces the number of times the air compressor has to be loaded and unloaded, which is highly beneficial for the compressor’s service life. (7) Minimize the use of elbows and various valves in the pipelines. (8) The ideal piping arrangement is for the main pipeline to circulate around the entire plant, so that compressed air can be obtained in both directions from any location. If the gas consumption in a certain branch line suddenly increases, the pressure drop can be reduced. In addition, appropriate valve assemblies should be installed on the ring main pipeline to facilitate isolation during maintenance. (9) When the air output pipes of multiple air compressors are connected in parallel, there is no need to install check valves at the output ends of the air compressors. 3. Foundation of the air compressor: The foundation of the air compressor should be built on solid soil, and its surface should be leveled before installation to prevent vibrations. If installed on an upper floor, vibration prevention measures must be taken; otherwise, vibrations can transmit to the lower floors or cause resonance, which can easily cause damage to both the air compressor and the building. Generally, the vibration speed of screw air compressors should be below 11.2 mm/s (for belt-driven units) and 7.1 mm/s (for coupling-driven units); in such cases, no special foundation is required. It is recommended to construct a platform foundation about 120 mm high, with dimensions slightly larger than the bottom area of the air compressor, to facilitate waste discharge. 4. Cooling system: The water quality standards for the cooling water used in water-cooled air compressors shall comply with the provisions of GB50050, \"Design Code for Industrial Circulating Cooling Water Treatment\". When softened water is available within the enterprise and the system is cost-effective, the circulating water in the system can use softened water. The main purpose is to prevent ions such as calcium and magnesium in water from undergoing chemical reactions due to high temperatures in the cooler, which would eventually lead to the formation of scale in the cooler and thus affect its cooling efficiency. The pressure of the cooling water is generally between 0.15 and 0.4 MPa, and the outlet temperature of the cooling water should be maintained at 6°C to 10°C higher than the inlet temperature. A filter screen should be installed on the cooling water inlet pipe, and pressure gauges, thermometers, and stop valves should be installed on both the inlet and outlet pipes. For air-cooled air compressors, attention must be paid to their ventilation conditions; they should not be placed near machines that generate high temperatures or in enclosed spaces with poor ventilation, to prevent shutdown due to high exhaust temperatures. If used in a enclosed space, ventilation equipment must be installed, with the air intake located at the bottom of the machine room and the exhaust outlet at the top, to facilitate the circulation of cold air. Generally, the intake and exhaust air volumes must be greater than the exhaust volume required for the air compressor’s cooling. 5. In power systems, when distributing electricity to air compressors, it is necessary to ensure the correctness of the supply voltage. Based on the power rating of the air compressor being used, select the appropriate gauge for the power cable; it is not permissible to use a cable with too small a gauge, as this may cause the cable to overheat due to excessive load and get damaged. The power cable must be a multi-strand copper core cable, with one of the three-phase four-wire system phases serving as the ground wire. It is best for air compressors to have their own separate power supply system; in particular, they should not be connected in parallel with other systems that consume large amounts of electricity. Otherwise, excessive voltage drops or imbalances in the three-phase current can cause the main motor of the air compressor to become overloaded and stop working. This is especially important to keep in mind when dealing with high-power air compressors. Moreover, the load on the power supply network should be even, with voltage fluctuations within ±5%; the imbalance in three-phase voltages is allowed to be within ±1%. There must be no connection points in the power cable running from the distribution cabinet to the air compressor. Select an appropriate air circuit breaker based on the power capacity of the air compressor to ensure the safety of the power system and maintenance operations. The grounding wires in power systems must be properly installed, and they must not be connected directly to compressed air pipes or cooling water pipes. 6. Appendix: 1 kW corresponds to a rated current of 2 amperes, and a copper wire with a cross-sectional area of 1 square millimeter can carry a current of 4 to 6 amperes. Specifications for common wires (rubber-coated copper wires): (number of cores × cross-sectional area in mm2 + number of cores × cross-sectional area in mm2). Examples: 3×10+1×6, 3×16+1×10, 3×25+1×10, 3×35+1×10; 3×50+1×16, 3×70+1×25, 3×95+1×35. The supporting capacity of a low-voltage 380V transformer is 3 times the rated capacity of the motor, while that of a high-voltage 6000V transformer is 2 times the rated capacity of the motor.