Screw pump leakage causes and precautions

Screw pump normal operation in the sudden leakage of a variety of reasons, one is the mechanical seal leakage, the second is the installation of different centrifugal, is the bushing is worn out, the pump body and liner into one (collectively referred to as the pump body), the shaft seal for the mechanical seal. Screw pumps have a variety of structural forms, generally small flow 0.2 ~ 6.5m3 / h, the pump body and liner into one (collectively referred to as the pump body), the shaft seal for the mechanical seal. The pumped liquid in the pump for axial uniform linear movement, so the pressure pulsation is small, stable flow, low noise, due to the small inertia of the rotating parts, the starting torque and vibration is very small. The main reasons for sudden leakage in normal operation of the screw pump are: pumping, cavitation or holding pressure for a long time, resulting in seal damage; the actual output of the pump is small, a large number of media pump circulation, heat accumulation, resulting in media cavitation, resulting in seal failure; return flow is large, resulting in suction side of the pipe containers (towers, kettles, tanks, pools) bottom of the slag flooding, damaging the seal; a longer period of time out of operation, restarting the no manual disc car The friction vice because of adhesion and tearing the sealing surface.
Screw pump work, due to the two slave screw and the active screw symmetrical engagement, so the radial force acting on the active screw all balanced, the active screw does not bear the bending load. The radial force along the entire length of the slave screw is supported by the pump cylinder bushing, so there is no need to set up another bearing at the outer end, basically does not bear the bending load. In operation, a layer of oil film formed between the cylindrical surface of the screw and the inner wall of the pump cylinder can prevent direct contact between the metals, so that the wear of the screw tooth surface is greatly reduced.
Screw pumps in the use of what to understand?
1, downhole gas separation: ineffective pump operation is often caused by gas interference, can be diagnosed by sonic level measurement and show power diagram. It is better to place the pump suction port below the fluid into the layer section, if placed above the gas separator should be used. If the valve seat short section is arranged at least 10ft below the bottom of the fluid entry layer section, effective gas separation can occur in the annulus, when the casing acts as the outer cylinder of the separator. However, well conditions often do not allow the pump to be placed below the fluid entry layer, so a downhole gas separator is considered. Conventional gas separator by the fluid into the part (such as shot hole short section), the outer cylinder (such as the bottom of a section of tubing with a plug) and the bottom of the pump sealing tube.
2, diagnosis of low energy effect: diagnosis is to determine the total rate of pumping system, and determine the total rate only need to measure the power of the input prime mover, determine the bottom of the well production pressure and accurate production test data. Typically, the total rate of a travelling beam pumping system should be half that, and if it is less than that, its performance should be improved. Techniques to improve the total rate include maintaining a high volumetric rate (matching pump specifications to wellbore injection, eliminating gas interference, controlling pumping with a pumping controller or timer) and replacing oversized motors.
3. The dynamometer determines the percentage of pump fill factor, and the application of an integrated data acquisition system can obtain both motor power and dynamometer data. One of the main uses of the dynamometer is to diagnose how the pump is operating and to analyse downhole problems. The application of production level measurements combined with the dynamometer can be used to find out whether the well is producing at a high rate, whether the column height is higher than the pump suction depth, whether the pump is not fully filled, and whether free gas is travelling up the casing annulus.