Shaft seal know how much?

Shaft seal know how much? 2020 - 10 - 13 to Chen about shaft seal you really know? Shaft seal how futile, shaft seal system and all equipments of purpose? Shaft seal before the operation of other systems need to prepare to what degree? Shaft seal how to adjust? Shaft seal pressure, temperature, is there any requirement? Shaft seal of commissioning of plant and system what effect? Since the seal is? Put the principle of shaft seal and economy of related problems, so there's plenty of knowledge of the shaft sealing system. Since knowledge so much, why not get practical knowledge to bai! Here share personal carefully at two o 'clock. First, what's the use of shaft seal in running? Why the role before the 'run'? Because the shaft seal is running. Shaft seal unit, in fact, the cold start, the operation of help warm axis and warming cylinder. Rely on turning, the relationship between shaft seal can evenly heating our big shaft, like under the grill when carbon cloth we slowly rotating wings make its heated evenly. And through the shaft seal gap can enter inside the cylinder shaft seal steam heating cylinder. So the cylinder and rotor can in turn cold rushed through the shaft seal before warm. RGL opportunity and warm process is bulge is poor, indicates that the rotor heat faster than the cylinder. Remember poisson effect? Is the negative differential expansion of a factor. And the shaft seal was put into is expanding difference can be offset with the poisson effect. When hot shaft seal of the trick is how to match the axis high sealing temperature quick mention right value, hot shot the differential phase expansion shaft seal is negative after first, according to the experience of high pressure cylinder exhaust end shaft end metal temperature is lower than the cylinder temperature about 120 - 150 degrees Celsius. Under the condition of the cylinder temperature is higher, can estimate the value of a shaft seal matching, of course, some units have a high pressure cylinder exhaust end shaft end temperature so much the better. With expansion difference before and after the operation of the change of the value can more accurately grasp the hedge car when the shaft seal was put into effect. Second, shaft seal, back to steam, cylinder exhaust steam/vacuum, and bearing shell, is how arrangement? Someone said that the math problem, count combining or alone to imagine compared to solve the problem, the former is the difficulty of a quarter. Said may be a bit exaggerated, but also revealed that clear the distribution structure of an object can greatly reduce our right in theory. Inside the cylinder as reference, from inside to outside cylinder exhaust steam/vacuum, shaft seal steam, shaft seal steam back, bearing shell ( As shown in the above, the above without bearing, if is in the diagram in figure inside the most left and right side) 。 And then we'll take this structural analysis problems. 1, since the seal before and after sealing steam flow? Since the seal before, that is, according to the direction of the arrows in figure, after the seal is the shaft seal steam ( The position of the figure X hole) As a user, exhaust steam source will be clear at a glance. 2, shaft seal pressure is too high, too low, have what harm? Imagine too low as the diagram of the shaft sealing X hole does not exist, vacuum directly to the outside world a breath; Y hole shaft seal pressure is too high as the picture there is no shaft seal no time back to steam, ran to the world and the bearing shell surrounding humidity is big, the bearing shell oil with water is possible. （ Source: zhao training)