Introduction to the effect of sealing material improvement on seal life

The machine itself has a congenital deficiency of misalignment between the center of the cylinder and the center of the crosshead slide, which causes the piston rod to deflect and vibrate, which has a great influence on the packing. The boot time is no more than 15min, the temperature can be increased to 80 °C, the new filler fill-in time is up to one week, and sometimes it needs to be repaired. The packing sealing ring is a single open straight cut from the manufacturer, so the first packing chamber has a small leakage and a large pressure difference, so the wear is fast and the sealing effect is quickly lost. In turn, the wear fails quickly. Moreover, the inner and outer rings of the seal ring are easily disengaged. The circumferential opening clearance of the sealing ring is too small, generally the inner ring s=lmm, the outer ring s'=1.2mm, can not be compensated after wear, and also causes the inner diameter deformation to be tightly clamped on the piston rod. In this case, the pressure difference is large, the wear is very fast, and the inner ring is hooped on the piston rod, causing axial displacement of the inner and outer rings, and in severe cases, the piston rod is pulled. The gap a between the sealing ring and the end face of the sealing box is too small, generally 0.14mm, so that the pressure of the sealing ring and the packing chamber is small, and the thermal expansion of the ring axial direction is limited, and the friction with the end face of the packing box cannot make the ring and the rod fit, and the air is leaked. The sealing effect is greatly reduced. The surface treatment of the piston rod is not clean, and the inner ring of the sealing ring is easily scratched, resulting in a tight seal. The bottom of the stuffing box is not flattened, causing the gap to be too large and leaking. The spring force is too tight, and the sealing ring cannot expand freely after heating, and the wear is accelerated. The cooling water path is fine, the circulating water is dirty, it is easy to block, and the cooling effect is lost. When the cooling water is interrupted, the stuffing box will heat up rapidly. If it is not found or stopped in time, the packing seal ring and the piston rod may be burned out. The quality of grinding and assembly during maintenance is not good, such as cutting the incision into a chamfered side, or the incision is not well misplaced, etc., which can cause air leakage. After the new seal ring is changed, when the air load is running in, it is afraid that the temperature is too high, so it does not dare to run continuously for a long time. The wind is blown against the piston rod and the stuffing box to reduce the temperature. Because the temperature cannot be measured, only the temperature can be guaranteed. Run-in at lower temperatures, but extend the run-in time.