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What issues need to be considered during the on-site installation of reciprocating compressors? I. General provisions 1. Compressors that are installed as a complete unit generally require the following disassembly and cleaning tasks； (1) For reciprocating piston compressors, the pistons, connecting rods, air valves, and packing should be removed, and the surface of the equipment as well as the removed parts should be cleaned thoroughly. Air valves and packing should not be cleaned with steam ； (2) In reciprocating piston compressors sealed with oil seals, when installed within the oil seal lifespan specified in the equipment’s technical documents, all components except the degassing valve need not be disassembled or cleaned. II. For compressors assembled on-site, the main units, components, and auxiliary equipment should be cleaned. Valve seats, packing, and other seals should not be cleaned with steam; after cleaning, any residual cleaning agents or moisture must be removed. It is also necessary to check for any damage or defects on the surfaces of the components and equipment. Once everything is in order, a thin layer of lubricant should be applied (components that come into contact with the medium in lubrication-free compressors should not be oiled). 1. Compressor installed as a whole: (1) The vertical and horizontal levelness of the compressor shall not exceed 0.2/1000. Measurements should be taken at the following locations: ① For horizontal compressors (including those with symmetric balance), measurements are taken on the compressor body slide surface or another reference surface ； ② For vertical compressors, remove the cylinder head and make measurements on the flat surface of the cylinder top ； ③ For other types of compressors, measurements are taken on the exposed part of the main shaft or on other reference surfaces. 2. Reciprocating piston compressors assembled on-site (1) The assembly of the casing and the main body shall meet the following requirements: ① Fill the casing with kerosene up to the highest level of the lubricating oil; no leakage should occur after 8 hours ； ② The longitudinal and transverse levels of the fuselage should not exceed 0.05/1000. And it should be measured at the following locations ； ③ For horizontal compressors (including those with symmetric balance), the longitudinal levelness is measured at two points, one in front of and one behind the slide, while the lateral levelness is measured at the bearing holes of the compressor body ； (2) Measured at the fuselage joint surface of the vertical compressor. (3) The L-type compressor is measured on the fuselage flange surface. III. The misalignment between the axis lines of the main bearing holes of the two compressor housings shall not exceed 0.05 millimeters. The assembly of the crankshaft and bearings shall meet the following requirements: (1) The oil passages of the crankshaft and bearings must be unobstructed and clean, and the oil plug on the crankshaft as well as the locking devices for the balance weights must be securely fastened ； (2) The bond between the shaft bearing steel shell and the bearing alloy layer should be strong; there should be no delamination or abnormal noises ； (3) The back side of the bearing shell should fit tightly against the bearing shell seat, with the contact area being less than 70% ； IV. The radial and axial clearances between the bearing shells and the main shaft journals shall comply with the provisions in the equipment’s technical documents ； V. The contact arc surface between the lower half of the split-thick-walled bearing shell and the shaft journal should be no less than 900, and the contact area should be no less than 70% of that contact arc surface ； For quarter-turn bearing shells, the contact area between the shaft journal and the lower and side shells should be no less than 70% of the area of each shell ； Thin-walled bearing shells do not require lapping during assembly, but their clearance must comply with the specifications outlined in the equipment’s technical documents ； VI. The levelness of the crankshaft should not exceed 0.1/1000; at positions every 900 degrees of rotation of the crankshaft, measure it on the main journal using a level ； VII. The deviation of the crankshaft axis from the slide way axis shall not exceed 01/1000 ； VIII. Check the distance between the cranks in the upper, lower, left, and right directions; the variation in this distance should comply with the specifications stated in the equipment’s technical documents. In the absence of such specifications, the variation should not exceed one ten-thousandth of the stroke length. IX. After the crankshaft is assembled, turn it a few times by hand; there should be no resistance. X. The assembly of cylinders shall meet the following requirements: 1. After the cylinders are assembled, the water circuits must undergo a leak test in accordance with the specifications provided in the equipment’s technical documents; there should be no leaks ； 2. The misalignment between the axis of the horizontal cylinder and the axis of the slide shall comply with the specifications in Table V-1.1, and the direction of this misalignment shall be consistent with the inclination direction of the slide ； When adjusting the cylinder clearance, no shims should be placed on the end face of the cylinder. 3. When aligning a vertical cylinder, the clearance around the piston within the cylinder should be even, with the deviation being less than 1/2 of the average clearance between the piston and the cylinder. XI. The assembly of the connecting rod shall meet the following requirements: 1. The oil passages of the connecting rod must be unobstructed and clean ； 2. The contact area between the thick-walled connecting rod big end bearing and the crank pin should be no less than 70% of the area of the big end bearing ； The thin-walled connecting rod big end bearings do not require lapping; the contact area between the connecting rod small end bearing (shaft bearing) and the crosshead pin should be no less than 70% of the area of the small end bearing (shaft bearing). 3. The radial and axial clearances between the big end bearing of the connecting rod and the crank pin shall comply with the specifications stated in the equipment’s technical documents ； 4. The radial clearance between the connecting rod journal bushing (bearing) and the crosshead pin, as well as the axial clearance between the journal bushing (bearing) and the crosshead body, must both comply with the specifications stated in the equipment’s technical documents ； 5. The connecting rod bolts and nuts shall be evenly tightened and locked according to the recommended tightening torque specified in the equipment’s technical documentation. XII. The assembly of the crosshead shall meet the following requirements: 1. The contact area between the crosshead slider and the slideway shall not be less than 60% of the area of the slider ； 2. The clearance between the crosshead slider and the slideway must meet the specifications stated in the equipment’s technical documents at all positions along the stroke ； 3. For symmetrically balanced compressors, the crossheads on both sides of the compressor body move in a symmetrical manner, and the forces acting on the sliders are different. During assembly, it is necessary to follow the markings provided by the manufacturer to prevent incorrect installation and ensure that the axis of the piston rod aligns with the axis of the slider track ； 4. The connecting bolts and locking devices of the crosshead pin must be tightened and secured firmly. 13. The assembly of the piston and piston rod shall meet the following requirements: 1. The piston rings shall first be inspected for light leakage inside the cylinder; there should be no more than two spots of light leakage across the entire circumference, each spot should cover no more than 45 degrees of arc length, and the distance from such spots to the opening of the piston ring should be greater than 30 degrees (except for plastic rings) ； 2. The clearance between the piston ring and the end face of the piston ring groove, as well as the clearance when the piston ring is inserted into the cylinder, must all comply with the specifications outlined in the equipment’s technical documents ； 3. The piston rings should rotate freely by hand within their grooves. When pressed by hand, they should fully sink into the grooves. When the piston is installed in the cylinder, the gaps between the piston rings in the same set must be staggered relative to each other. All such gaps must also be offset from the valve ports ； 4. The clearance between the piston and the cylinder bore shall comply with the provisions in the equipment’s technical documentation. For horizontal cylinders and pistons with bearing alloy cast at the bottom, the upper clearance may be approximately 5% less than the average clearance compared to the lower clearance ； 5. The contact area between the piston support surface coated with piston bearing alloy and the cylinder mirror surface shall not be less than 60% of the arc surface of the piston support. 6. The piston rod should be firmly connected to the piston, and it should also be securely locked to the crosshead ； 7. The clearance between the piston and the inner and outer dead centers in the cylinder shall comply with the provisions specified in the equipment’s technical documents. 14. The assembly of the packing and the oil scraper shall meet the following requirements: 1. When assembling the packing, its oil, water, and air passages must be unobstructed and clean ； 2. The contact area between the end faces of each packing ring and the end face of the packing box should be no less than 70% ； 3. The contact area between the packing, the wiper, and the piston rod should be no less than 70% of the area of that set of rings ； 4. When assembling the scraper, the scraping edge must not be rounded, and the orientation of the edge must not be reversed ； 5. After the filler and wiper are assembled, the gaps in all areas shall comply with the specifications stated in the equipment’s technical documents ； 6. The locking device of the filler gland must be securely locked. 15. The assembly of the air valve shall meet the following requirements: 1. The elasticity of the air valve spring shall be uniform, and there shall be no sticking or misalignment of the valve disc and the spring ； 2. The gas valve adjustment device and the valve disc lift shall comply with the provisions of the equipment’s technical documents. 3. After the air valve is assembled, kerosene should be injected to conduct a tightness test; only intermittent droplet-like leaks are allowed. 16. The assembly of the lubrication system shall meet the following requirements: 1. The oil pipes shall have no sharp bends, twists, or flattening ； 2. The transmission mechanism connecting the crankshaft to the oil pump, or the crankshaft to the oil injector, should operate smoothly ； 3. The pipelines, valves, filters, coolers, and other components of the lubrication system shall be subjected to a tightness test at the pressure specified in the equipment’s technical documents after assembly; if no such specification is provided, the test shall be carried out at the rated pressure, with no leakage allowed. 4. The oil pipe should first be vented and drained before being connected to the oil supply and lubrication points. 17. Auxiliary Equipment: Before installing the auxiliary equipment of the compressor (such as coolers, gas-liquid separators, buffers, dryers, air storage tanks, filters, vent tanks, etc.), it is necessary to check against the construction drawings to ensure that the positions of the pipe connections, the bolt holes, and the foundation are correct, and to verify that all pipelines are unobstructed. 18. Auxiliary equipment subjected to pressure shall undergo strength and tightness tests at the pressures specified in the technical documents; in the absence of such specifications, the strength test pressure shall be in accordance with Table V-12.2, while the tightness test pressure shall be the rated pressure. 19. The strength test shall be conducted using water as the medium; the equipment shall be held at the test pressure for 5 minutes, after which the pressure shall be reduced to the rated value. A thorough inspection shall then be carried out by gently tapping with a hammer at a distance of 150 millimeters from both sides of the weld, and there shall be no leakage or deformation. 20. When conducting a tightness test using air or an inert gas as the medium, it is advisable to use the following methods for inspection: 1. Apply soapy water to the bolts and joints such as rivets and welds, and observe for any bubbles ； 2. The leakage rate or pressure drop of the gas over one hour (with at least 1 hour of observation) shall comply with the specifications stated in the equipment’s technical documents. 21. Pressure-bearing auxiliary equipment may be exempted from strength testing and only subjected to a tightness test if it meets all three of the following conditions ； 1. Strength tests have been conducted at the manufacturing plant, and a certificate of conformity is available ； 2. No visible signs of damage on the surface ； 3. Install within the period specified in the technical documents. 22. The levelness of the tubes in a spray-type cooler, as well as the verticality of their vertical surfaces, must both comply with the specifications stated in the equipment’s technical documents ； If not specified, it shall not exceed 1/1000 ； The water overflow from the spill tray is even. 23. The levelness of horizontal equipment and the verticality of vertical equipment shall comply with the provisions specified in the equipment’s technical documents ； If not specified, it should not exceed 1/1000. Twenty-four, Other: 1. The installation standards for the fuselage must be high; it is recommended to use the gluing method for installation, as it saves time. 2. Before pouring the foundation, it is essential to carefully check the positioning dimensions of the corner bolts on the compressor casing and the motor casing; every dimension must be verified. Otherwise, if there are significant dimensional deviations after the foundation is poured, it will be difficult to address the issue. 3. It is recommended to use a steel wire to check the coaxiality between the cylinder and the middle body during installation. The manufacturing capabilities in the compressor industry are sufficient to ensure the required precision; however, if the workers lack a strong sense of responsibility, it is very likely that there will be a significant deviation in the coaxiality between the cylinder and the middle body. We encountered such a situation during installation – the deviation between the center of the cylinder and the center of the middle body was 0.5 mm, which is quite large. 4. For pipeline installation, it is essential that the workers clean the inside of the pipelines thoroughly to facilitate purging. 5. Pay close attention to the fixing of pipelines, and ensure they are installed in strict accordance with the installation standards.