Steam feed water pump mechanical seal cooling water return water temperature anomaly analysis and processing

Steam feed water pump mechanical seal cooling water return water temperature anomaly analysis and deal with 2020 - 12 - 13 Zhao Chao ( Jiangsu KanShan power generation co. , LTD. , jiangsu xuzhou) 1, the background of mechanical seal is the key to the steam feed pump parts, is composed of a pair of relative motion of the sealing ring and its components, and relying on its face the close contact between the formation of the small axial liquid membrane sealing role. Pump at high speed, the dynamic and static ring between the two end face working liquid in a sealed cavity generate heat by friction, in order to prevent evaporation, should be timely to ring and static ring friction heat is derived. To this end, installed on the fringes of the mechanical seal mechanical seal cooling function, to reduce the mechanical seal chamber temperature. For the convenience of observing reflux condition, on the return pipe cooling function body set backwater viewer. Backwater observer structure as shown in figure 1, backflow fluid ( Below red mark line) Rely on diversion effect of the internal structure of cyclone tangential enters the backwater swirl chamber, formed in the cavity interior circulation, circulation flow through horizontal backwater tubular packed into the backwater pipes, in the chamber has red, white, two small floating ball, rely on the fluid drive rotation, used to observe water reflux. Figure 1 backwater observer principle in figure 2, the occurrence of the incident on October 24, 2017 8 am 50 points, steam feed water pump mechanical seal cooling function body backwater viewer leakage, came to the abnormal return observation Windows summon up and burst may at any time. Staff on-site measuring backwater viewer import water temperature 88 ℃, export water temperature 32 ℃, comprehensive consideration is not for the steam feed pump mechanical seal cooling function backwater viewer internal structure block body, back to the water volume is reduced, resulting in abnormal return water temperature rise, organic glass Windows heated uplift deformation, backwater loathsome burst open window. 3, reason analysis diagram 2 backwater internal disintegration of disintegration of vortex structure diagram window vortex structure is found, as shown in figure 2, backwater viewer internal vortex dislocation structure of import and export position is very big, very obvious dislocation creasing, inlet and outlet port congestion, backwater viewer flow reduce, imagine working mechanical seal when the heat generated by the constant, so the return water temperature to rise due to lower flow rate, inlet pressure rise due to return not free. Backwater observation window material of organic glass, glass heat deformation temperature ( HDT) Generally does not exceed 80 ℃, temperature and pressure caused by abnormally elevated burst open Windows. 4, improvement measures according to the original return water pipe connection at the inlet and outlet of the viewer and size, choose new type impeller backwater viewer, as shown in figure 3, the type of backwater viewer depend on water to turn rushed inside impeller cutting, can be directly observed clearly backwater, according to the size of the impeller rotating speed qualitative observation of water flow. In addition, the impeller axis deflection arrangement, only part of the backwater tangential turning impeller, most of the fluid through the straight pipe section back to the mother tube, this reduces the backwater viewer local resistance, reduce the line resistance loss of cooling water cooling system. Figure 3 new backwater viewer appearance figure 5 and conclusion in this paper, steam feed water pump mechanical seal cooling function body cooling system, analyses the reasons of blowout of backwater observation window is inside the backwater viewer, vortex structure of import and export flow at the inlet and outlet of the dislocation caused obstruction, return water temperature and pressure, eventually lead to burst open Windows. With the collapse of the analysis of the structure of the backwater viewer in, find out its defects, and adopts a new type of backwater observer is put forward. Combining with the abnormal problem, the next step will continue to inspect and replace other observer of recycle water cooling water system, insure the normal operation unit cooling water system. （ Source: turbine)