Request for instructions on the installation of the mechanical seal for the GSB-L2-15/325 centrifugal pump

Horizontal high-speed pump? It would be better if you sent some pictures so that everyone can help you. I recall that there are a seal on the oil side of the gearbox and a seal on the medium side of the pump; both of these are sold in bulk, so pay attention to the compression amount

Last edited by wdingshao on 2017-11-6 13:42: Vertical high-speed pumps developed by the 11th Aerospace Research Institute

(II) Procedures for disassembling and assembling the equipment, maintenance techniques, and precautions: 1. Use a 14-mm wrench to remove the coupling cover; simultaneously, use 19-mm and 24-mm wrenches to remove the four tension rods of the pump body. The bolts for the cover and the tension rods are located in the T-shaped grooves of the pump body. After removing the tension rods, the coupling cover can be taken off. Next, remove the coupling bolts and diaphragm, make marks on them to indicate their positions, and store them separately. 2. Contact the electrical technician to remove the instrument probes from the pump body, as well as any attached pipelines and oil filters. When removing the lubrication oil pipelines, a bucket should be prepared to collect the lubricating oil remaining inside the pump. Also, check all the bolts; if the anti-corrosion paint applied has made it difficult to remove the bolts, use a paint remover to eliminate the anti-corrosion paint from the threads before attempting to remove the bolts. Use a 30mm wrench to remove the bolts that connect the pump body to the pump casing. If it is possible to remove the nuts, do so and place them in a safe location. If the nuts cannot be removed directly, turn them as far back as possible; once the pump body has been lifted, proceed with removing them ； After tightening the lifting rings at both ends of the pump body, turn it back two turns to prevent the pump body from getting stuck if it is inverted later on ； Adjust the four tie rods, located above and below the CC-type basket screws (tightening clips) on both sides, to the same position; then tighten the basket screws on both sides simultaneously to lift the pump body evenly. After lifting it, remove any remaining connection bolts of the pump body and store them properly. When lifting the pump, make sure that the guide rods are in place and lift it horizontally to avoid damaging the impeller’s inducer wheel. When the pump body has been lifted to its maximum height, tilt it so that the inducer wheel at the bottom of the impeller is above the pump casing (Figure 1); thereafter, pull the pump body out completely along the slide, and cover the pump casing portion to prevent foreign objects from entering. 3. Invert the entire pump body by 180°, use a feeler gauge to measure the distance from the back of the impeller to the back plate and record it; this provides a basis for checking whether the impeller is in place after reinstallation. Use a small flathead screwdriver to loosen the locking gasket between the inducer wheel and the impeller, then use a 27mm wrench to remove the inducer wheel. The inducer wheel is connected to the shaft via studs that thread in a counter-clockwise direction; after removal, the impeller can be taken out by gently tapping it. Remove the impeller backplate – there are positioning pins between this backplate and the pump body; during installation, align these pins properly before lowering the components evenly to prevent misalignment. 4. Remove the seal medium mechanical seal as well as the throttle ring seat. After removing the impeller backplate, the moving ring of the seal medium mechanical seal can be taken off. After marking the sealing element, it can be removed entirely using a 17mm socket wrench. Once the sealing element is removed, the static ring seat can be detached by using a 10mm wrench to loosen the three bolts. There is an O-ring between the static ring seat and the sealing element; this O-ring can be removed by using two flat-head screws to pry it out from both ends, or by using one flat-head screw to pry it out gradually along the outer circumference. After removal, check for any damage to the moving and static rings. The upper part of the sealing element is the throttle ring, which is made of PTFE rubber; check the degree of wear on this PTFE rubber and replace it if necessary. Figure 4: The replaced O-ring seal. 5. After removing the sealing assembly, the oil-sealing mechanical seal on the pump body can be seen; the stationary ring seat can be accessed by using a 10-mm wrench to remove the three bolts, and it can then be taken out with a flathead screwdriver. Thereafter, the rotating ring as well as the shaft sleeve can be removed. An O-ring serves as a seal between the rotating ring and the shaft sleeve. Upon removal, it was found that the O-ring had been severely deformed and no longer functional, so it is inferred that this deformation of the O-ring was one of the main causes of the oil leakage (Figure 2). Inspection of the sealing surfaces of the mechanical seal revealed slight wear, and there was a lot of mud inside the seal’s flushing water pipe, with the pipe holes almost completely blocked by mud. Further inspection showed cracks in the mechanical seal due to the medium used (Figure 3). 6. After disassembly is complete, clean all components at the site; remove scale from between the throttle ring and the stationary ring (Figure 4), clear any dirt inside the seal flushing pipeline, prepare the necessary spare parts, and wait for reassembly. 7. During reinstallation, insert the seal moving ring of the oil sealing machine along the shaft, being careful to avoid any collisions. Replace the static ring assembly; after placing the entire assembly back into the pump body, tighten the three bolts using a 10-mm wrench. Next, place the O-ring between the dynamic ring and the shaft sleeve on top of the dynamic ring, and finally insert the shaft sleeve, making sure that the O-ring fits evenly inside it. 8. Check whether the gasket between the pump body and the seal unit is damaged or deformed, and decide whether to replace it. Then remove any impurities from between the throttle ring and the stationary ring. After replacing the stationary ring and the O-ring, reinstall the entire seal unit. During reinstallation, ensure that the markings are in place and that the positioning pins between the two components are aligned, and tighten everything evenly using a 17mm socket wrench. Once tightening is complete, insert the O-ring and the moving ring. 9. Reinstall the impeller backplate onto the pump body. There are two O-rings in place to provide sealing between the impeller backplate and the pump body, and there are also positioning pins between them. After alignment during reinstallation, the backplate is lowered in place. There is another O-ring that provides sealing between the rotating ring and the impeller; during reinstallation, this O-ring can be placed into the corresponding groove on the impeller. To prevent the O-ring from falling out during reinstallation, a small amount of 704 sealant can be applied between the O-ring and the impeller. After inserting the key into its slot, the impeller is reinstalled. Finally, a 27mm wrench is used to reinstall the drive wheel onto the impeller; there is also an O-ring providing sealing between the drive wheel and the impeller. Once reinstallation is complete, a feeler gauge is used to measure the distance from the back of the impeller blades to the backplate, in order to verify that everything has been installed correctly. The locking washer is then lifted using a flathead screwdriver. 10. Turn the pump body back over as a whole and push it back using the slide rails; the pump body should also be tilted during this process to prevent the impeller from coming into contact with anything. Before the pump body drops, screw the bolts into the base. After replacing the O-rings between the impeller backplate and the pump casing, lower the pump body evenly. As it descends, tighten the nuts gradually – one nut at a time – until the pump body is fully lowered. Then tighten the bolts that connect the pump body. Reset the pipelines, instrument probes, couplings, coupling guards, struts, etc., to complete the reinstallation process. Clean the oil cooler and oil filter; a large amount of sludge was found, which is believed to be the cause of the blockage in the flushing pipeline. After testing, the temperature of the bearing housing improved significantly, dropping from 80°C to 50°C. 11. The positioning of this pump’s casing differs from that of other pumps; in this case, the impeller is held in place by an inducer wheel, while the impeller itself relies on the dynamic ring of the seal medium for support. The dynamic ring is supported by the shaft sleeve, which in turn relies on the dynamic ring of the oil seal. Finally, the dynamic ring of the oil seal is supported by the shoulder of the high-speed shaft, thereby achieving the desired positioning effect. 12. This pump body mostly uses O-rings for sealing, and the number of O-rings that need to be replaced at one time can be around 10 (Figure 4). Except for the lack of O-ring sealing between the moving ring of the oil seal and the shaft shoulder, O-rings or gaskets are used for sealing between all other components. II. Maintenance methods and improvement suggestions 1. It is recommended to consider raising the pump body support as a whole or using tensioning clips to lift the pump body to its highest position; since the bottom inducer wheel still remains below the pump casing, it is necessary to hold the inducer wheel by hand when moving it along the slide track in order to avoid collisions. Given the limited space available for maintenance, holding the inducer wheel by hand may pose a risk of injury. 2. It is recommended to fabricate special supports for this pump body; when removing the mechanical seal, the entire pump body needs to be inverted by 180°. The pump body relies solely on the lifting rings on both sides, and someone must hold it steady throughout the maintenance process to prevent it from flipping back and falling, which could cause danger. Special supports are fabricated to place the entire pump body on them; this helps to save labor, prevents accidents, and also facilitates the disassembly and reinstallation of the pump body.