The effective sealing of the valve depends on the overall condition of each component. Pay special attention to make sure that the equipment that needs to be replaced has been effectively isolated according to the site and system before the packing installation.
3. Measure and record the diameter of the shaft / rod, the diameter and depth of the stuffing box, and record the distance from the bottom of the stuffing box to the top when sealing the ring with water.
4. Select packing 1) ensure that the selected packing meets the operating conditions required by the system and equipment; 2) calculate the cross-sectional area of the packing and the number of packing rings required according to the measurement records; 3) inspect the packing to ensure that it is free of defects; 4) ensure that the equipment and packing are clean before installation.
5. Preparation of packing ring 1) the braided packing is wound on the shaft with proper size, or the calibrated packing ring cutting machine is used; the packing is cut cleanly to butt (square) or miter (30-45 degrees) according to the requirements, one ring is cut at a time, and the shaft or stem is used to check whether the size is appropriate. 2) Molded packing ensures that the ring size fits accurately with the shaft or stem, and if necessary, cut the packing ring in accordance with the packing manufacturers operating instructions or requirements.
6. When installing packing, carefully install one packing ring at a time, and surround each ring on the shaft or valve rod. Before installing the next ring, make sure that this ring is completely in place in the stuffing box. The next ring should be staggered and arranged at least 90 degrees apart. Generally, 120 degrees is required. After the last ring is installed, tighten the nut by hand and press down the gland evenly. If there is a water seal ring, check whether the distance from the top of the stuffing box is correct. At the same time, make sure that the shaft or stem can rotate freely.
7. Adjust packing 1) pump packing (1) continue to tighten the gland nut by hand; (2) after the pump is turned on, adjust the gland nut to allow a little more leakage; (3) slowly tighten the gland nut to gradually reduce the leakage until the leakage reaches an acceptable level; (4) if the leakage stops suddenly, screw back the gland nut and readjust to prevent the packing from overheating; (5) adjust the leakage rate to reach one Stable state is enough. 2) For valve packing, consult the packing manufacturer or the technical department of the enterprise for the specified torque or compression percentage, and tighten the gland nut as follows: (1) apply torque to the gland nut to 30% of the full torque or the compression percentage of the party; (2) repeatedly open and close the valve several times, when the valve is in the closed position, apply all torque; (3) repeat step (2) 3 or 4 times.
8. After several hours of operation, check the adjustment condition of the gland and tighten it if necessary. When the gland cannot be further adjusted, the packing must be replaced.