Installation and adjustment method of packing for

2022-08-22
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Installation and adjustment methods of packing for valves

the effective sealing of pumps and valves depends on the overall condition of each component. Special attention should be paid to ensuring that the equipment requiring packing replacement has been effectively isolated according to the site and system before packing installation. The following contents are used to guide maintenance personnel, engineers and assemblers to correctly install and adjust packing

the effective sealing of the pump and valve depends on the overall condition of each component. Pay special attention to make sure that the equipment that needs to replace the packing has been effectively isolated according to the site and system before the packing installation. The following contents are used to guide maintenance personnel, engineers and assemblers to correctly install and adjust packing

1. When removing the old packing and replacing it with a new one, the required tools need to use special tools and pre tighten the gland nut with a fastener. In addition, standard safety facilities should be used frequently and relevant safety regulations should be observed. Before installation, first be familiar with the following equipment: check the cutting machine of the packing ring, check the torque wrench or wrench, safety helmet, internal and external calipers, the lubricant of the fastener, reflector, cable combustion experimental machine, also known as bundle cable combustion machine packing extractor, cutting tool of the packing, vernier caliper, etc.

2, cleaning and inspection 1) slowly loosen the gland nut of the stuffing box to release all the residual pressure in the packing assembly; 2) Remove all old packing and thoroughly clean the stuffing box of the shaft/rod; 3) Check the shaft/rod for corrosion, dents, scratches or excessive wear; 4) Check other parts for burrs, cracks and wear, which will reduce the service life of packing; 5) Check whether the stuffing box has excessive clearance and the eccentricity of the shaft/rod; 6) Replace the parts with major defects; 7) Check the old packing as the basis of failure analysis to find out the cause of early failure of packing

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 to the top of the stuffing box when sealing the ring with water

4. Select packing 1) ensure that the selected packing should meet the operating conditions required by the system and equipment; 2) Calculate the cross-sectional area of packing and the number of packing rings required according to the measurement records; 3) Inspect the packing to ensure that it is free from defects; 4) Make sure the equipment and packing are clean before installation

5. Preparation of packing ring 1) braided packing is wrapped around a shaft of appropriate size. Students have done a questionnaire survey in Colleges and universities to wrap packing, or use a calibrated packing ring cutting machine; Cut the packing neatly into butt joint (square) or miter joint (degree) according to the requirements, cut one ring at a time, and check whether the size is appropriate with the shaft or valve rod. 2) The molded packing ensures that the size of the ring is accurately matched with the shaft or valve stem. If necessary, cut the packing ring according to the operation instructions or requirements of the packing manufacturer

6. Install packing carefully one packing ring at a time, surrounding 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, and the next ring should be staggered, at least 90 degrees apart, generally 120 degrees. The analyzer is a scientific analysis and detection instrument in the integration of optical motor 1. After the last ring of the instrument is installed, tighten the nut by hand and press the gland evenly. If there is a water seal ring, check its distance from the top of the stuffing box and the maximum compressive stress at the inner wall orthogonal to it; Whether it is correct to generate the maximum tensile stress on the inner wall of the front 1 orientation and the outer wall of the rear 1 orientation. At the same time, ensure that the shaft or valve rod can rotate freely

7. Adjust the packing 1) pump packing (1) continue to tighten the gland nut by hand; (2) After starting the pump, adjust the gland nut to allow a little more leakage at this time; (3) Slowly tighten the gland nut and gradually reduce the leakage until the leakage reaches an acceptable level; (4) If the leakage stops suddenly, the gland nut should be screwed back and readjusted to prevent the packing from overheating; (5) Adjust the leakage rate to a stable state. 2) For valve packing, consult the packing manufacturer or the technical department of the enterprise about the provisions of torque or compression percentage, and tighten the gland nut according to the following steps: (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 for several times. When the valve is in the closed position, apply all the torque; (3) Repeat step (2) 3 or 4 times

8. Tighten and replace again. 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

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