Feed water pump mechanical seal spit water temperature anomaly analysis and processing

Feed water pump mechanical seal spit water temperature anomaly analysis and deal with 2019 - 03 - 10 ( Jiangsu xuzhou, Zhao Chao) 1 background of feed water pump mechanical seal is the key to water pump seal parts, it 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 tiny liquid ring sealing effect. Pump at high speed, the dynamic and static ring between the two end face working liquid because of friction heat, will ring and static ring friction heat export, as shown in figure 1, through the spiral pipe cooler cools, the working fluid into the mechanical seal chamber inside, heat by the spiral casing is passed to the closed cooling water. Mechanical seal liquid cooling diagram (figure 1 Th e) 2 problem description found in the unit operation process, mechanical seal working liquid pours out the abnormal temperature increase, as shown in figure 2, the pump speed 4250 r/min, the scene temperature found mechanical seal working liquid pours out end up to 57 ℃ temperature, suction side 42 ℃ temperature, with increasing speed, working liquid pours out frequent close to end temperature alarm value, a serious threat to the safe operation of the unit. General considerations on the issue in question may be because the magnetic filter the dirt which reduces the working liquid flow so that the temperature rise, but the magnetic filter strip inspection found no obvious impurity, after the replacement of new magnetic filter mesh, still not solve the problem of abnormal temperature. Figure 2 mechanical seal cooling water heat transfer difference figure among them: the adjustment before A minus Mechanical seal working liquid suction side; B - Mechanical seal working liquid pours out side; C - The closed cooling water imports. D - The closed cooling water exit. 3 root cause analysis and improvement through field analysis found that, as shown in figure 3 installation contact, spiral casing above four interfaces, in turn, work for mechanical seal liquid suction side, mechanical seal liquid pours out side B, closed cooling water import export D C, closed cooling water. Spiral casing has been used is in forward heat transfer way, according to the heat exchanger along the current way, we can know that current heat exchange of the logarithmic mean temperature difference is bigger, for the same thermal physical properties of two kinds of working medium, the same heat transfer coefficient K and the heat transfer area A, logarithmic mean temperature difference, the greater the delta tm, the greater the heat & Phi; , the greater the spiral cooling casing in the thermal efficiency is higher. Figure 3 mechanical seal cooling pipe installation contact figure based on the above theoretical analysis, using the downtime maintenance opportunity, will adjust cooling tube heat exchange way, from downstream type heat transfer improvement for countercurrent heat transfer mode. After the improvement, the following figure mechanical seal cooling diagram 4. Figure 4 mechanical seal liquid cooling diagram ( Counter-current) Figure 5 mechanical seal cooling water after the heat transfer end difference adjustment figure 4 conclusion will spiral casing instead of after the counterflow heat exchange cooling, at the same speed conditions, the counterflow heat exchange the logarithmic mean temperature difference delta tm = 13. 4 ℃, delta tm = 11 th logarithmic mean temperature difference can be compared. Increased by 2 ℃, 4 ℃, the temperature difference in heat added 17. 5%, therefore, the mechanical seal with suction side temperature of 42 ℃ to 37. By 57 ℃ 8 ℃, spit out the temperature reduction to 52. 4 ℃, decline significantly. By way of the cooler and countercurrent heat exchanger of quantitative analysis showed that different ways of heat transfer of cooling effect is greatly influenced.