York multi-stage centrifuge maintenance

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1 Basic structure of the compressor body (1) The components of the active end (power input end) are, from outside to inside, the active end transmission shaft (the end outside the body is connected to the speed increase box through a coupling, and the end inside the body is connected to the main shaft through a threaded screw to the rotor shaft), mechanical seal, bearing, and air seal. (2) Looking from the active end to the passive end, the inside of the body is composed of guide vanes, first to fifth stage diffusers, and baffles. The outer edges of the partitions at each stage are sealed with the casing to separate each stage. The rotor is located within the inner circle of the diffuser and partition. There is a labyrinth air seal between each stage partition and the rotor shaft. There is also an air seal between the diffuser and the impeller. A balance piston is installed between the fifth-stage partition and the rotor shaft. Behind the fifth-level partition is the balance room, and behind the balance room is the fuel tank. The oil tank is a separate cavity outside the main body. The end of the oil tank close to the rotor serves as the end cover of the gas compression chamber. It is equipped with a gas seal, a radial bearing and a thrust bearing. The thrust bearing is specially designed as the main oil pump of the oil tank (in principle, there are several grooves on the outer end surface of the thrust bearing. When it rotates with the rotor, it can do the same work on the lubricating oil as the impeller, thus producing a pressurizing effect. The front end cover of the oil pump also serves as the auxiliary shoe of the thrust bearing). The main oil pump is connected to the auxiliary oil pump outside the body through a pipeline, and a jet pump is installed in the pipeline to supply oil to the oil pump. 2. The disassembly and disassembly of the compressor, starting from the driven end, is as follows: disassemble the oil tank end cover; disassemble the main oil pipe in the oil tank. The steps are to disassemble the external connector of the machine and unscrew the connection between the oil pipe and the main oil pump front cover; dismantle the instrument. At this time, it is necessary to disassemble various instrument probes; disassemble the thrust bearing (main oil pump). The steps are: disassemble the oil pump front cover, disassemble the main oil pump cavity, disassemble the thrust bearing; disassemble the radial sliding bearing; disassemble the driving end mechanical seal; disassemble the main shaft end drive shaft. ;Remove the driving end bearing bush;Remove the driving end bearing seat;Reinstall the bearing box and dummy bushings, which are used to support the rotor, protect the rotor shaft, and facilitate the subsequent removal of the bulkhead diffuser;Lift out the upper cover;Remove the fuel tank cavity;Remove the fifth-stage rear engine Shell and balanced piston sleeve; remove the fifth-stage rear partition. The fifth-stage rear partition is a whole and the first-stage diffuser is a whole. The other partitions and diffusers are split. The fifth-stage rear partition is first removed and then installed back into the fuel tank cavity to support the rotor. At this time, you can remove the partition and diffuser by lifting out the upper part of the partition or diffuser, and then unscrewing the lower part from the bottom. Note that when removing the partition, the balance piston sleeve that matches the balance piston has been removed. At this time, the balance piston must be covered with rubber to avoid collision and scratches; replace the fuel tank cavity; replace the dummy bearing bush, use a jack to hold the rotor shaft, increase the gap between the shaft and the lower body, and use a guide rod to install the dummy shaft The matching clearance between the bush, the false bearing bush and the shaft is large, easy to disassemble, and is only used to support and protect the rotor shaft; remove the balance tube, there are three balance tubes, which are connected to the balance chamber behind the balance piston and the third-stage outlet in three directions; disassemble the fifth-stage diffuser to the first-stage partition plate, and follow the order of the body parts, first Remove the baffle and then disassemble the diffuser. The baffle and the lower part of the diffuser are screwed out from the bottom to above the impeller and lifted out; lift out the fuel tank; lift out the rotor. When it is adjusted out with a crane, it will avoid collision. Use jacks and wooden blocks to support and stabilize the rotor; disassemble the active end bearing box; disassemble the active end air seal cavity, and The sealing cavity body and the inlet guide vane are matched, and a copper rod is used to knock out the other end of the first-stage diffuser; the inlet guide vane is lifted out, and the guide vane and the active end cover are designed to be a whole; the first-stage diffuser is lifted out, and the first-stage diffuser is integrated with the guide vane, so it needs to be disassembled at the end. 3. The assembly sequence of the compressor is roughly reversed with reference to the disassembly sequence. Only the key steps and adjustment of the matching clearance are described below: 3.1 Install the rotor. Before installing the rotor, install a dummy bearing bush in the bearing box and lock it with a spring retaining ring for support after the rotor is installed. In the subsequent operation, the oil tank needs to be used to support the other end of the rotor. At this time, the passive end also needs to be installed with a dummy bearing bush. This neck-stressed bearing bush has a thrust bearing to limit its axial movement when the machine is running, but there is no corresponding limiting mechanism after the machine body is disassembled. When installing the rotor, the false bearing bush may move and damage the instrument probe. Tools must be used to limit its axial movement according to the actual situation. 3.2 Install the diffuser and partition. Install the lower part of the diffuser first. After lifting it to the appropriate position with a crane, carefully rotate it to the lower part of the body, and then install the corresponding upper part. There are impeller seals and shaft seals respectively installed between the diffuser and partition and the rotor. At this time, care must be taken not to collide with the impeller seal ring to avoid collision deformation. Then install the partition. When installing the partition, adjusting the matching gap between the partition shaft seal ring and the shaft is the focus of the entire assembly process, which is related to whether the machine can operate normally. There are positioning pins on the edges of the diffusers at each stage to fix their positions on the casing. The diffusers and partitions are connected together by bolts. After the bolts are screwed on, the partitions are also fixed. Since the relative position of the diffuser and the casing is fixed, the radial position of the rotor is also fixed, so adjusting the matching gap between the shaft seal ring and the shaft needs to be achieved by adjusting the relative position of the partition plate and the diffuser. The installation procedure of the baffle is to first install the upper half, put on the connecting bolts between the baffle and the diffuser, adjust the connecting bolts to roughly adjust the gap between the half gas seal ring and the shaft on this half baffle, then turn the baffle and diffuser downward as a whole, then install the lower half, align the baffle and gas seal ring with the upper half, put on the bolts, then turn the whole body back to the working position, and finally make further fine adjustments to the gap. The adjustment procedure is as follows: first use a feeler gauge to measure the matching clearance between the upper and lower parts, and then adjust the relative position of the partition and the diffuser based on this. Here, the purpose is achieved by prying the partition and adjusting the connecting bolts between the two. Adjust repeatedly until the measured value is relatively reasonable, and the gap is detected by other means. Because the gap between the bulkhead shaft seal and the shaft may be too small during the assembly process, you can use the method of first placing a copper sheet between the air seal ring and the shaft, tightening the bolts, and then taking them out to make the gap reach a larger value. The purpose of adjustment is to make the upper and lower clearances between the shaft seal ring and the shaft as equal as possible, and at the same time keep the total clearance at a reasonable value, that is, it cannot affect the air-tightness of the shaft seal too much and cannot be too small to cause friction between the rotor and the separator. For gap detection, one is to use a feeler gauge to measure the gap value, the other is to turn and listen to the sound of the rotor rotating to see if there is any friction sound between the rotor and the shaft seal, and the third is to turn and turn the rotor to detect the friction and tightness of the rotor by feeling. The first detection method here is objective but not accurate enough due to the limitations of the body structure. The second and third detection methods are effective but highly subjective and need to be used in combination. 3.3 Reinstall the oil tank. By comparing with the disassembly data, install a gasket of appropriate thickness (thicker than the required value) on the sealing end of the oil tank and the main body. In addition to sealing, it is also used to adjust the amount of shaft channeling in the next step. 3.4 Adjusting the shaft channeling amount Adjusting the shaft channeling amount is another key point in the assembly process. The main purpose is to make the shaft channeling amount after installing the thrust bearing half of the amount when the shaft has no axial restrictions before the thrust bearing is installed. This is achieved by adjusting the gasket at the sealing surface between the oil tank and the main body. In order to make the measurement data accurate, before measuring, a special torque wrench must be used to tighten some bolts on the active end and passive end according to the design requirements, so that the measuring components are in the working position. Use a meter on the passive end to measure the shaft deflection, install the thrust bearing and measure again. The purpose of adjusting the shaft deflection is achieved by adjusting the thickness of the sealing gasket between the oil tank and the casing. Note: If the gasket fragments are not left behind and affect the body seal, the integrity of the removed gasket must be confirmed. 3.5 Adjust the runout value of the thrust bearing. First, use a meter to measure the runout value of the end face and outer circle when the shaft rotates. Adjust the tightness of the thrust bearing screw and move the thrust bearing to change its position and adjust the runout value. If the measurement still does not meet the standard, remove the thrust bearing, rotate it 60 degrees and reinstall it, measure again, and repeat this until the runout value meets the standard. 3.6 When installing the mechanical seal, since the relative position of the mechanical seal moving ring and the body is fixed in the axial direction, the compression amount of the mechanical seal can be adjusted by adjusting the gasket on the sealing surface of the mechanical seal gland and the body, and adjusting the relative position of the fixed ring and the body.