Common Fault Analysis of Water Ring Vacuum Pump
First, the water ring vacuum pump failure 1. Vacuum pump mechanical seal leakage reasons 1.1. Improper assembly of mechanical seals Replacement of non-mechanical seals, the removal process was found on the ring seal O-ring is not installed. O-ring should be installed into the seat ring seat seal groove inside, and disassembly inspection found that the O-ring is not so installed, but wrong installed in the spring positioning piece, resulting in deformation of the spring, can not fully achieve the axial static seal The role, resulting in leakage. 1.2. Machine seal cooling water pressure is too large Sealing ring sealing surface sealing force is applied by the spring on the ring. When the cooling water pressure is too large, the water pressure will act on the static and dynamic ring, the static ring is stationary, so the hydraulic pressure will promote the ring, to the opposite direction of the static compression spring, thus weakening or offset static and dynamic annulus The bonding force, resulting in leakage of sealing surface. After the overhaul to the power end machine seal into the cooling water leak test, inlet valve open 2/3, the machine seal intact, when the water valve open more than 2/3, the machine seal leakage occurs. Tripartite (maintenance side, Alumina Motor Division, Sichuan Daewoo mechanical seal factory) preliminary judgment is caused by excessive water pressure, it is recommended to be repaired after the motor is turned on and use, to further identify the real cause of leakage . 1.3. Static and static ring seal surface rupture This is the first time to replace the pump seal leak the main reason. The power end and the non-power end machine seal are assembled on the same shaft, the impeller is installed in the middle of the shaft, and both ends of the shaft are mounted with bearing support and fixed. When replacing the power end or non-power end machine seal separately, the corresponding end bearing (bearing seat) must be disassembled to remove the old machine seal and install the new machine seal. At this time, because of the gravity of the shaft and impeller, The impeller and the shaft will inevitably fall down and the shaft will be tilted to the bearingless end. Because the unassembled end of the static ring is bolted to the pump cover fixed, and moving ring is fixed on the shaft with the shaft rotation, the other due to the static ring inner ring and the shaft with a small gap, when the shaft collapsed Tilt, will result in: a, not removed at one end of the static and dynamic ring relative displacement, so that the static and dynamic ring sealing surface of each other illegally squeezed, causing fragmentation; b, the shaft is pressed directly on the end of the static ring static ring, resulting in static ring Sealing surface broken or broken. Through the understanding of the previous few changes to the analysis, resulting in one end of the replacement of good and the other side of the seal on the leak are caused by the above factors. In fact, our operators have also taken into account this issue, but to take the wrong approach: replace the previous few are the use of hoist to disassemble the shaft to prevent the shaft up and down swing, the actual operation of this method is to prove that There is a big mistake, especially not suitable for such a large vacuum pump seal installation. The reason is hanging point, difficult to fully control the tension gourd, it is difficult to avoid the shaft up and down swinging. 2, vacuum crank difficult analysis 1) the positioning of the pump bearing clearance is not adjusted. The two ends of the pump bearings are double row tapered roller bearings, double row tapered roller bearings inner and outer ring of two rows of conical contact, the inner ring can be taken from the outer ring. Between the two columns there is a bearing clearance adjustment ring, that is, the original bearing clearance is based on two rings between the inner ring to control, the general bearing clearance has been adjusted. Bearing assembled on the shaft, one of the two columns of the inner ring on top of the shoulder, the other column locked by the locking cap on the shaft, locking, the two columns of inner ring and the spacer ring should be closely together With the shaft rotation, the outer ring and the bearing box tightly fixed. If the gap adjustment spacer thickness is less than the original thickness, when the locking cap, the two rows of inner and outer ring unconventional force squeeze, so that the bearing rotation difficult or unable to rotate. 2) Bearing inner ring is not installed in place The inner ring is not installed in place will occur 1) The above problems, because the relative displacement of the inner and outer rings relative to the front and rear, resulting in one of the two inner rings and outer ring unconventional force extrusion. When removing the power end bearing, it is found that there is a great eaten mark on the axial surface where the bearing is installed. The analysis and judgment of the fact that the bearing inner ring does not completely overhang the shaft shoulder is the main reason for the difficult turning. 3) Impeller and the gap between the two ends of the pump did not adjust the water ring vacuum pump impeller and the clearance between the two ends of the pump is to move both ends of the bearing to adjust. The adjustment method is to add and subtract the gasket between the bearing seat and the bracket positioning surface on which the bearing seat is installed. 4) Machine seal ring static seal surface after the break card help. Second, the water ring vacuum pump seal replacement procedures for the correct disassembly 1. Remove the pump seal at both ends of the cooling water pipe; 2. Remove the power end pulley (replace the non-power end machine seal without this step); 3. respectively Power end and non-power end of the mechanical seal removed hanging on the shaft, pay attention to light and light; this step is particularly important to avoid damage to the intact end of the machine seal. (Note: This step is also necessary if the bearings on both ends are to be repaired separately.) 4. Remove the bearing gland to be replaced with the end cap and remove the bearing lock cap. 5. Use the top wire to attach the bearing housing together with the bearing Top removed. (In this case, it is necessary to use the hoist to hoist the shaft from the dismounting end and facilitate the ejection of the bearing); 6. Remove the old machine seal from the shaft; 7. Carefully cover the new machine cover after inspection; 8. Clean check bearing is intact, check the bearing clearance is appropriate; 9. The bearings, bearing seat back to the shaft, and bearing grease, tighten the inner cap locking cap, fitted with bearing gland (which One step also need hoist shaft coordination); 10. Try to see the car is easy, pay special attention to the process of turning the car do not damage the machine seal; 11. respectively, the two ends of the mechanical seal from the shaft back into the sealed box inside; . Return the pulley (non-power end without this step); 13. Return the condensate water pipe, into the condensate after the disc leak test; 14. Maintenance is completed, the work place cleared.