Oil production platform segment multistage centrifugal pump bearing high temperature

Oil production platform segment multistage centrifugal pump bearing high temperature, 2019 - 11 - 07 JuZhaoGang lau ( Cnooc energy development and equipment technology co. , LTD. ) Abstract: the production platform sectional multi-stage centrifugal pump using angular contact bearings after a certain period of drive on the temperature rise of progressive type cannot be used properly, previous maintenance methods are difficult to solve the phenomenon of high temperature, through to the internal structure of centrifugal pump and the analysis of the failure phenomenon, quick to judge and rule out the phenomenon of bearing caused by high temperature. Key words: segment multistage centrifugal pump; Bearing; Balance the hub; Balanced set of; Axial force an overview, oil production platform sectional multi-stage centrifugal pump bearing high temperature is a common fault, some cases replace the bearing, oil changing regular maintenance methods cannot solve the high temperature condition, based on the drive end a diagonal contact bearing high temperature position to determine the direction of axial force, and by adjusting the balance of the hub and balanced set of completely solve the bearing clearance of high temperature phenomenon. Some platform, fault phenomena described two sectional multi-stage centrifugal pump is running to 1 years later, gradually approaching the drive end bearing temperature 80 ℃ alarm value ( Shut off the value of 85 ℃) , through to the disintegration of bearing box, found the drive bearing on a diagonal contact bearing the last tray due to temperature change color. Three, failure analysis of the sectional multi-stage centrifugal pump axial balance: out of the final stage with the pressure of liquid, and after a balanced set of radial clearance flow balance in the cavity in front of the boss, the cavity under high pressure. Balance the hub after balance are connected to the pump inlet pipe, the pressure approximation for the inlet pressure. Such balance hub pressure are not equal on both sides, as a result, the backward of axial thrust, namely the balance. Balance force and axial force on the contrary, thus automatically balance the axial thrust of the impeller. When axial thrust is greater than the force balance of the hub of the impeller, pump rotor will move to the side entrance, and due to the effect of inertia, this move will not immediately stop on the equilibrium position, but to beyond the limit, balance the hub axial gap caused by excessive decreases, and reduce leakage, balance the hub before the cavity pressure, and balance the hub on the balance force increases, and more than impeller of axial thrust, pull the rotor and the side toward the exit. Have inertia of this process is the same, make balance hub axial gap increases, cause the balance is less than the axial thrust, rotor and moved towards the side entrance, repeat the above process. This process is automatic, when the pump work, the rotor is always in a balanced position so that the axial moving, but little momentum, out of the appearance is very ugly. Balance the hub and axial end clearance balanced set of security, under the condition of the drive end into a diagonal contact bearing only bear the residual axial force of the weaker, when the balance of the hub and balanced set of axial end face of the running for a long time, wear gradually increase; Balance the hub in order to seek a balance in the balance of the hub with balanced set of axial clearance gradually wear conditions, due to the effect of axial force, the rotor moving gradually to the suction side, when wear gap increase the axial force is also increasing at the same time, more than a diagonal axial bearing capacity of bearing contact, axial mill bearing friction increase, easy to cause the bearing or sintered at high temperature. Four, fault judging 1, through the bearing installation pictures ( 一) And high temperature bearing position ( b） Show that the axial force to the suction side, confirming the balance of the hub and balanced set of axial clearance caused by wear and tear; 2, operation records show that the bearing is gradually warming with use cycle, balance the hub and balanced set of axial end face wear gap is gradually wear lead to bearing heating up step by step. Five, troubleshooting 1, dismantle the drive end bearing box and interior accessories; 2, the demolition of mechanical seal and bearing suspension; 3, demolition of balancing the hub, and pull out of balance; 4, balance the hub and balanced set of axial end face wear and tear, can adopt three kinds of maintenance scheme 4. 1, the balance of the hub and balanced set of replacing the new spare parts; 4. 2, balance the hub and balanced set of axial end face to repair, restore the original size; 4. 3, balance the hub and balanced set of axial end face turning processing; Urgent for production, and ultimately select two parts axial end face for turning processing, surface roughness of 1. 6μ m； 5, two parts after turning, axial length for parts have change, set on the back to balance compensation GangDian, in balance and balance drum axial end face under the optimum condition, for half the total jumped out of the rotor, the allowable deviation & plusmn; 0. 5毫米; 6, in turn back to suspension bearing, bearing box and internal attachments, into a diagonal contact bearings after installation, the rotor to the suction side pushed to the limit, ensuring balance the hub and balanced set of axial end clearance of 0. 04 ~ 0. 8 mm, into a diagonal contact bearing in the bearing indoor momentum is zero. 12 ~ 0. 18毫米; Six finished assembly, test, and restore all the attachments for pump testing, bearing temperature constant operating 6 hours to 45 ℃, the temperature of the continuous running 72 hours with no obvious change, the issue is resolved. Seven, conclusion pump belongs to common failures bearing high temperature, such equipment must be in-depth analysis of high temperature phenomenon, this case, by the position of the bearing high temperature, and the equipment working principle and internal structure, quick to find a true for troubleshooting, ensure production platform safe and reliable operation of the equipment. Source: the science and technology, 2019, 6