Fan installation

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Chapter 1 General Provisions for Fan Installation Article 1 This chapter applies to the installation of centrifugal ventilators, centrifugal blowers, centrifugal compressors, axial flow ventilators, Roots blowers, and Darrieus blowers. Article 2: This section contains the specialized technical provisions for the installation of fans (excluding auxiliary equipment). The general technical requirements for installation work shall be in accordance with the provisions set out in Volume 1 of these specifications, namely the \"General Provisions\". Article 3: The foundation, specifications, and shock absorption devices for fan installation shall meet the relevant design requirements. Article 4 The unpacking inspection of the fan shall meet the following requirements: 1. Based on the equipment packing list, verify whether the main installation dimensions of the impeller, casing, and other components (such as the center distance between the foot hole centers, the diameter and orientation as well as center distance of the inlet and outlet flange holes, and the center height of the shaft) are in accordance with the design specifications ； II. The rotation direction of the impeller shall comply with the provisions in the equipment’s technical documents ； III. The intake and exhaust openings shall be covered with tight lids to prevent dust and debris from entering ； IV. Check the rust prevention status of all machined surfaces on the exposed parts of the fan, as well as whether the rotor has suffered significant deformation or severe rusting, damage, etc. If any of these issues are present, it is necessary to discuss possible solutions in conjunction with the relevant parties. Article 5: The handling and lifting of fans shall comply with the following requirements: For fans that are installed as a single unit, the ropes used for handling and lifting must not be tied to the rotor, the casing, or the lifting rings on the bearing covers ； II. For fans assembled on site, the tying of ropes must not damage the surface of the components, as well as the central holes at both ends of the rotor and gear shafts, the thrust surfaces of the bearing shells, the end faces of the thrust discs, the connection bolt holes on the horizontal mid-plane of the casing, the rotor shaft journals, and the shaft seals – none of these areas should be used for tying purposes ； III. The rotors and casings of fans used for transporting special media, which are coated with protective layers, must be carefully protected to prevent any damage ； IV. The rotor and gear shafts should not be placed directly on the ground to roll or move. Article 6: In addition to being cleaned and kept unobstructed, the pipelines of the fan’s lubrication, oil cooling, and sealing systems shall also undergo strength tests on their pressure-bearing parts. If the equipment’s technical documents do not specify a test pressure, for hydraulic testing this pressure shall be 1.25 to 1.5 times the maximum operating pressure, while for pneumatic testing it shall be 1.05 times the operating pressure ； Lubricants and sealing fluids prepared on-site should be descaled and cleaned. Article 7: The intake pipes, exhaust pipes, valve control devices, as well as the oil circuits of the gas heating and cooling systems of fans shall all be provided with separate supports and firmly connected to the foundation or other structures ； When connecting various pipelines to the fan, the flange surfaces should be aligned and pressed flat; forceful pulling or twisting should be avoided. The fan casing should not bear the weight of other components to prevent deformation of the casing. After the piping installation is completed, it is necessary to recheck whether the misalignment of the unit meets the requirements. Note: The oil circuit systems of medium and small-sized units (such as units similar to the DA350-61) do not require a separate support system. Article 8: The installation of monitoring instruments and meters for the automatic control equipment attached to fans shall be carried out in accordance with the provisions of the equipment’s technical documents. Article 9: When it is necessary to cut or weld the piping connected to the fan, the fan casing should not be deformed; this should generally be done after the piping is separated from the casing. Article 10: The exposed parts of the fan’s drive mechanism shall be covered with guards ； When the air inlet of a fan or its intake duct is directly connected to the atmosphere, a protective mesh or other safety devices should be installed. Chapter 2: Centrifugal Ventilators Article 11: The disassembly, cleaning, and assembly of centrifugal ventilators shall comply with the following requirements: 1. The casing and bearing housing shall be removed and the rotor taken out for cleaning; however, ventilators with direct motor drive do not require disassembly for cleaning ； II. The cooling water pipeline of the bearing should be unobstructed, and the entire system should undergo pressure testing; if the equipment’s technical documents do not specify a particular pressure value, it should generally be no less than 4 kilograms per square centimeter. III. Clean and inspect the adjustment mechanism, which should rotate smoothly. Article 12: The installation of the entire unit shall be carried out by placing it directly on the foundation and leveling it using paired shims. Article 13: For units assembled on-site, the machined surfaces on the base must be properly protected to prevent rust or damage; when the base is placed on the foundation, it should be leveled using paired shims. Article 14: The bearing housing and the base must be firmly connected together. The longitudinal levelness shall not exceed 0.2/1000, as measured using a level on the main shaft; the lateral levelness shall not exceed 0.3/1000, as measured using a level on the horizontal mid-plane of the bearing housing. Article 15: Before grinding the bearing shells, the axis line of the rotor must first be aligned with the axis line of the casing. At the same time, the gap between the impeller and the air inlet, as well as the gap between the main shaft and the shaft holes in the rear side panel of the casing, must be adjusted to meet the specifications outlined in the equipment’s technical documents. Article 16: When assembling the main shaft and bearing shells, inspections shall be carried out in accordance with the provisions of the equipment’s technical documents. A clearance of 0.03 to 0.04 millimeters should be maintained between the bearing cover and the bearing bush (by measuring the outer diameter of the bearing bush and the inner diameter of the bearing housing). Article 17: When assembling the casing, the position of the casing should be aligned using the rotor’s axis as a reference, and the axial and radial gaps between the impeller’s inlet and the casing’s inlet should be reduced to within the ranges specified in the equipment’s technical documents. At the same time, it is necessary to check whether the foundation bolts are properly tightened. If the gap values are not specified in the equipment’s technical documents, the axial gap should generally be 1/100 of the impeller’s outer diameter, while the radial gaps should be evenly distributed, with their values ranging from 1.5/1000 to 3/1000 of the impeller’s outer diameter (the higher value applies when the outer diameter is smaller). During adjustment, strive for a smaller gap value to improve the fan’s efficiency. Article 18: When aligning a centrifugal ventilator, the axial deviation between the fan shaft and the motor shaft shall be such that the radial displacement does not exceed 0.05 millimeters, and the inclination does not exceed 0.2/1000. Article 19: For fans equipped with rolling bearings, if there is a difference in the axial alignment of the bearing holes in the two bearing housings, this can be adjusted after the rotor is installed, ensuring smooth rotation. Chapter 3 Axial Flow Fans Article 20 The disassembly, cleaning, and assembly of axial flow fans shall be carried out in accordance with Article 11 of this section, in addition to meeting the following requirements: 1. It is necessary to check whether there is any damage at the root of the blades and whether the tightening nuts are loose ； II. For vertical units, the gearbox, gear set, or worm gear set should be cleaned. Article 21: The entire unit shall be installed directly on the foundation, leveled using paired shims. Article 22: For units assembled on-site, the assembly shall meet the following requirements: 1. For horizontally split units, the upper part of the main air duct and the rotor shall be removed, and the lower part of the main air duct, bearing housings, and base shall be assembled on the foundation; thereafter, they shall be leveled using paired shims ； II. For vertically split units, the intake chamber should be placed on a foundation and leveled using paired shims; thereafter, the bearing housings should be installed such that they make even contact with the bottom surface. The misalignment of the two bearing holes relative to the common axis shall not exceed 0.05 millimeters ； After grinding the bearing shells, place the main shaft horizontally on them. Fix the shaft end with a dial indicator, and use the intake chamber seal as a reference to measure the misalignment between the main shaft and the intake chamber; this value should not exceed 2 millimeters. Then, install the impeller, casing, stator, and diffuser in sequence ； III. The levelness of vertical units shall not exceed 0.2/1000; this is measured using a level on the hub. The axial deviation between the drive shaft and the motor shaft, as well as the radial displacement, shall also not exceed 0.2/1000 ； IV. For horizontally and vertically split units, the axial deviation between the fan shaft and the motor shaft shall not exceed 0.05 millimeters, and the angular deviation shall not exceed 0.2/1000 ； The longitudinal levelness of the unit shall not exceed 0.2/1000, and the lateral levelness shall not exceed 0.3/1000 (as specified in the technical documentation for axial flow exhaust fans used in power plants); measurements shall be taken using a level on the horizontal midplanes of the main shaft and the bearing housing. Article 23: When adjusting the blades, their angles shall be adjusted in accordance with the specifications provided in the equipment’s technical documents, and the nuts used to secure the blades shall be tightened. If it is necessary to remove the blades from the hub, they must be positioned according to the marked indicators to prevent misalignment that could disrupt the rotor’s balance. If the blade needs to be replaced due to damage, after replacing the blade, the nut must be tightened in accordance with the requirements specified in the equipment’s technical documentation. Article 24: When assembling the main shaft and bearing shells, inspections shall be carried out in accordance with the provisions of the equipment’s technical documents. Article 25: The gap between the impeller and the main duct (or casing) shall be evenly distributed and in accordance with the provisions in the equipment’s technical documents. If there are no specific regulations regarding the difference in radial gaps on the corresponding sides, the values specified in Table V-2.1 shall be applied. The difference in the radial gaps between the impeller and the corresponding sides of the main duct: Table V-2.1. Impeller diameter (millimeters): ≤600, >600–1200, >1200–2000, >2000–3000, >3000–5000, >5000–8000, >8000. The difference in the radial gaps on these corresponding sides should not exceed (millimeters): ±0.5, ±1, ±1.5, ±2, ±3.5, ±5, ±6.5. Article 26: The joints at the upper part of the main duct, as well as the connection flanges between the intake chamber and the casing or stator, as well as those connecting the front and rear ducts and the diffuser, must all be aligned properly and sealed tightly. The front and rear bellows, diffusers, etc., should be firmly connected to the foundation, and their weight must not be borne by the main air duct (or intake chamber) to prevent deformation of the structure. Chapter 4: Roots and Vane Blowers Article 27: The cleaning, disassembly, and assembly of Roots and Vane blowers shall comply with the following requirements: 1. Clean the gearbox and its gears ； II. Inspect the interior of the rotor and casing ； III. Clean the lubrication system to ensure it is unobstructed and clean. Article 28: The clearances between rotors (including both the forward and reverse directions), between the rotors and the casing, and between the rotors and the wall panels shall all comply with the specifications stated in the equipment’s technical documents. Article 29: Fans shall be leveled using paired shims, and the longitudinal levelness of the shaft shall not exceed 0.2/1000. Chapter 5: Centrifugal Blowers and Compressors Article 30: The cleaning, disassembly, and assembly of centrifugal blowers and compressors shall comply with the following requirements: 1. All components and auxiliary equipment must be thoroughly cleaned; after the anti-rust grease on their joints is removed, a lubricating layer should be applied for protection (except in cases where special requirements apply) ； II. The vertical mid-plane of the casing shall not be removed for cleaning (for machines with a cylindrical structure, follow the provisions in the equipment’s technical documentation); the diffuser, return duct, bearing housing, etc. can be cleaned without removal ； III. The oil pumps, filters, oil coolers, safety valves, etc., in the lubrication system and sealing system should be removed and cleaned; with the exception of the oil coolers, they do not necessarily require separate pressure testing ； IV. The gas regulation devices and gas cooling systems should be disassembled and cleaned; their pressure-bearing components can generally be subjected to pressure testing ； For those with special requirements, a tightness test shall be carried out in accordance with the provisions of the equipment’s technical documents. Article 31: When aligning centrifugal blowers and compressors, the following requirements shall be met: 1. For directly coupled units, alignment shall be carried out longitudinally using a level on the shaft, with the levelness not exceeding 0.03/1000 ； Measure horizontally using a level on the dividing surface within the casing; the levelness shall not exceed 0.1/1000 ； II. When leveling units equipped with speed governors, use a level to make measurements on the shaft journals in the vertical direction; the levelness should not exceed 0.02/1000 ； Horizontally, it is measured on the horizontal mid-plane of the lower casing using a level (see Figure V-2.1); the levelness deviation should not exceed 0.1/1000 ； The alignment of the entire unit is generally carried out with reference to the speed increaser. Article 32: When installing the base or the entire unit, the following requirements must be met: First, pair of wedge shims should be selected according to the size of the unit. For units with a rotation speed of over 3000 revolutions per minute, the contact area between each shim, as well as between the shims and the base, must be no less than 70% of the surface area in contact; local gaps shall not exceed 0.05 millimeters ； II. After the shims in each group are selected, they should be placed together and marked to prevent confusion ； III. If the base is composed of multiple components, it is necessary to check, in accordance with the equipment’s technical documentation, whether the positions of the anchor bolts for the casing, bearing housings, etc., are consistent ； IV. The clearance between the guide keys on the base (horizontal or vertical flat keys) and the machine body should be uniform, and in accordance with the specifications outlined in the equipment’s technical documents. If not specified, the interference in the keyway during assembly should be 0.01 to 0.02 millimeters ； In the slidable keyway, the values of C1+C2 for the gaps on both sides should be 0.04 to 0.08 millimeters; the top gap c should be 0.5 to 1.0 millimeters, and the recess of the set screw below key a should be 0.3 to 0.5 millimeters (see Figure V-2.2). Article 33: When the bearing housing and lower casing are installed on the base, the following requirements must be met: 1. For units in which the bearing housing and lower casing form a single unit, the lower half of the unit should be placed on the base, and leveling should be carried out using the bearing holes as a reference (for units equipped with a gearbox, the gearbox is generally used as the reference for this purpose) ； II. In units where the bearing housing and the lower casing are not integrated, the bearing housing should first be installed on the base, and leveled using the bearing holes as a reference; simultaneously, any misalignment between the lower casing and the axis of the main shaft must be corrected (in units equipped with a gearbox, these adjustments are generally made using the gearbox as a reference) ； III. The bolts that connect the anchor claws on the bearing housing or lower casing, which are equipped with guide keys, to the base should be properly fixed. The gap between the bolt and the screw hole, as well as the gap between the nut and the base, should comply with the specifications outlined in the equipment’s technical documents. In the absence of such specifications, the gap c between the nut and the base can generally be between 0.03 and 0.06 millimeters (see Figure V-2.3). IV. The bearing housing and the base, or the anchor claws of the lower casing and the bearing housing and the base, must fit tightly together. Before tightening the bolts, use a feeler gauge to check the local gaps; for units with a rotation speed of 3000 revolutions per minute or less, this gap should be no more than 0.05 millimeters, while for units with a rotation speed higher than 3000 revolutions per minute, it should not exceed 0.04 millimeters. Note: The base refers to the anchor claws of the bearing or the lower housing. Article 34: The bottom surface of the gearbox shall fit tightly against the base; before tightening the bolts, a feeler gauge should be used to check that the local gap is not greater than 0.04 millimeters. Article 35: The contact arc surface between the bearing shell and the shaft journal, as well as the top clearance and side clearance, shall all comply with the provisions specified in the equipment’s technical documents. If a certain parameter does not meet the requirements, repair or scraping is permitted; however, when repairing or scraping the bearing shells, care must be taken to correct any misalignment between the rotor and the sealing device, and to ensure that the gap between the rotor and the sealing device complies with the specifications outlined in the equipment’s technical documents (for tilting-pad bearings, these specifications must also be followed). Article 36: The axial and radial runouts of all parts of the rotor (such as the main shaft, impeller, balance disk, thrust disk, and coupling) shall not exceed the values specified in the equipment’s technical documents. Article 37: The joint surface between the upper and lower casings shall be tight; before the bolts are tightened, the allowable local gap shall comply with the provisions in the equipment’s technical documents. If not specified, the following requirements shall be met: 1. For systems with a working pressure of 10 kilogram-force per square centimeter or less, the gap shall not exceed 0.12 millimeters (except for sintering blowers) ； For those with working pressure above 10 kgf/cm2, the gap should not exceed 0.08 mm ； II. The connection bolts must not be damaged, and if there is any sealing filler or coating between the joint surfaces, it must be applied evenly in accordance with the specifications provided in the equipment’s technical documents. Article 38: When assembling the gearbox, the following requirements shall be met (for planetary gear gearboxes, the provisions in the equipment’s technical documents shall apply): 1. The various clearances of the bearing shells (top clearance, side clearance, etc.), the contact arc surfaces, and the number of contacts per unit area shall comply with the specifications in the equipment’s technical documents; grinding may be necessary when required ； II. The center distance between the shafts of the gear set, the degree of misalignment, the tooth side clearance, and the contact patch size shall comply with the specifications stated in the equipment’s technical documents ； III. The mating surfaces of the upper and lower housings of the gearbox must be tight; before the bolts are tightened, the local gap there should not exceed 0.06 millimeters, and the connection bolts must not be damaged. Article 39: The interference fit values for all upper bearing backs and bearing caps (or gland plates), as well as the contact area between the lower bearing backs and the bearing holes, shall comply with the specifications provided in the equipment’s technical documents. In the absence of such specifications, the interference fit value is generally 0.03 to 0.07 millimeters, and the contact area should generally be no less than 75%. Article 40: When electric motors, steam turbines, gas turbines, and speed increase devices are connected to blowers and compressors, the allowable degree of misalignment must comply with the specifications stated in the equipment’s technical documents. 　Chapter 6: Commissioning Article 41: The commissioning of fans shall be carried out in two steps; the first step is a test of the mechanical properties ； The second step is to design the load test run. Air is generally used as the compression medium. When the specific gravity of the working medium designed for the fan is less than that of air, it is necessary to calculate the power required for trial operation using air, as well as to determine whether the resulting temperature rise affects normal operation. If there is such an impact, design load trials must be carried out using the specified medium. Article 42: Before the trial operation of the fan, the following requirements must be met: 1. The name, model, main properties of the lubricating oil, as well as the amount to be added, shall comply with the specifications stated in the equipment’s technical documents ； II. Thoroughly flush the lubrication system and tight-filling system in accordance with the provisions of the equipment’s technical documents ； III. The interlock devices for the circulating oil supply systems of blowers and compressors, the anti-rotation devices, the shaft displacement alarm devices, the interlock devices for the sealing systems, the anti-rotation devices, the shaft displacement alarm devices, the interlock devices for the sealing systems, the control devices for the water circuit system, as well as the valves and instruments, must all be sensitive and reliable, and must comply with the specifications stated in the equipment’s technical documents ； IV. The rotation direction of the electric motor or steam turbine, gas turbine shall be consistent with that of the fan ； V. When rotating the fan rotor, there should be no sticking or friction ； VI. The valves and auxiliary devices should be in the position that results in the lowest load when the fan is operating ； VII. Each individual unit within the machine set shall undergo a single-unit test run in accordance with the provisions of the equipment’s technical documents ； VIII. Check all safety measures. Article 43: When testing the fan at its rated speed, the required time shall be determined in accordance with the technical documentation of the equipment, taking into account the characteristics of the fan’s use and the altitude of the location where it will be used. If not specified, under normal circumstances the following rules shall apply ； I. For centrifugal and axial flow fans, the time should be no less than 2 hours ； II. At the actual operating pressure, the service life of Roots and vane blowers should be no less than 4 hours ； III. For centrifugal blowers and compressors, the operation time at minimum load (i.e., when the unit is running) should be no less than 8 hours, and continuous operation at design load should be no less than 24 hours ； IV. The fan must not operate within the surge zone (the surge flow range is specified in the equipment’s technical documents). Article 44: When the fan is in operation, the following requirements must be met: 1. For fans driven by electric motors, a test must be conducted in which the fan is started once and then stopped immediately; only after it has been confirmed that there is no friction between the rotor and the casing, as well as no abnormal noises, can the fan continue to operate (the starting of fans driven by steam turbines or gas turbines shall be carried out in accordance with the specifications provided in the equipment’s technical documents) ； II. After the fan starts up, it must not remain in the vicinity of the critical speed (the critical speed is determined by the design) ； III. When the fan starts up, the temperature of the lubricating oil should generally not be lower than 25°C; during operation, the temperature of the oil flowing to the bearings should generally not exceed 40°C℃ ； IV. Before starting the fan, it is necessary to check first whether the circulating oil supply is functioning properly. After the fan stops rotating, the oil pump should be turned off only after the temperature of the bearings returns to below 45°C ； V. In units equipped with a starting oil pump, the starting oil pump should be activated before the fan is started, and it can only be stopped once the main oil pump is supplying oil properly ； Before the fan stops operating, the start-up oil pump should be turned on first; after the fan ceases to rotate, the start-up oil pump should be stopped only after the oil temperature in the bearings drops to 45°C ； VI. After the fan reaches its rated speed, it should be adjusted to its minimum load (with the exception of Roots and vane-type blowers) and operated mechanically for the specified time. Afterwards, it should be gradually adjusted to the design load to check whether the prime mover is operating beyond its rated capacity; if no abnormalities are detected, operation should continue until the specified time is reached ； VII. The installation height of the high-position fuel tank, based on the mid-plane of the bearing, should be no less than 5 meters above this level ； VIII. The cooling water pressure in the lubricating oil cooling system of the fan must be lower than the oil pressure ； 9. When the fan is in operation, the oil pressure at the inlet of the bearing lubrication system should meet the specifications stated in the equipment’s technical documents. In the absence of such specifications, the normal inlet oil pressure should be between 0.8 and 1.5 kilogram-force per square centimeter. An alarm should be triggered when the oil pressure for high-speed, light-load bearings falls below 0.7 kilogram-force per square centimeter, and the machine should be stopped if the pressure drops below 0.5 kilogram-force per square centimeter. When the oil pressure drops to the upper limit of the aforementioned value, the start-up oil pump or the backup oil pump should be activated immediately. At the same time, the cause of the low oil pressure must be identified and addressed ； 10. The radial amplitude of the bearings during the operation of the fan shall comply with the provisions in the equipment’s technical documents; in the absence of such provisions, it shall meet the requirements specified in Tables V-2.2 and V-2.3 ； XI. When the fan is in operation, the bearing temperature should comply with the specifications stated in the equipment’s technical documents. Table V2.2 shows the radial amplitude (in both directions) for bearings of centrifugal, axial flow fans, Roots, and Darrieus blowers:
Speed (rev/min): ≤375, >375–650, >550–750, >750–1000, >1000–1450, >1450–3000, >8000.
The amplitude should not exceed the following values (in millimeters): 0.18, 0.15, 0.12, 0.10, 0.08, 0.06, 0.04.

Table V-2.3 shows the radial amplitude (in both directions) for bearings of centrifugal blowers, compressors, and gearboxes:
Speed (rev/min): ≤3000, >3000–6500, >6500–10000, >10000–18000.
The amplitude of the main machine bearings should not exceed the following values (in millimeters): 0.08 for rolling bearings, and 0.05, 0.04, 0.03, 0.02 for sliding bearings.
The amplitude of gearbox bearings should not exceed 0.04, 0.04, 0.03.
Note: The amplitudes listed in the above tables refer to the values measured when the sensor’s contacts are placed vertically on top of the bearing surface. Provision: In the absence of specific provisions, it shall generally comply with the requirements in Table V2.4 ； Bearing temperature gauge V-2.4. For rolling bearings and sliding bearings, the temperature should not exceed 80°C or 60°C respectively. Twelve. During the operation of the fan, it is necessary to check at regular intervals whether the temperature and pressure of the lubricating oil, the temperature and flow rate of the cooling water, the radial vibration amplitude of the bearings, the temperature and pressure of the gas in the exhaust pipeline and between various sections, the functions of the protection devices, as well as the current, voltage, and power factor of the motor, all conform to the specifications outlined in the equipment’s technical documents. Records should be kept of these measurements ； 13. Once the fan’s trial operation is complete, the relevant devices should be adjusted to a state ready for startup.