Graphite packing installation and adjustment accuracy is very important!

Graphite Packing Installation and Adjustment Before installing the packing, make sure that the graphite packing equipment has been effectively isolated in accordance with the site and system. The following content is used to guide maintenance personnel, engineers, and assemblers to properly install and adjust the packing.

The graphite packing is the continuation of the solid phase carbonization reaction, and almost all of the non-carbon elements dominated by nitrogen in the carbon fiber are spilled away, and graphite fibers having a carbon content of nearly 100% are obtained. The release of nitrogen is the result of a further condensation reaction at the small hexagonal carbon network plane, and a solid graphitization condensation reaction is possible. About 6% to 7% of nitrogen is removed during the graphitization process, leaving behind many void defects and stomata in the escape path, resulting in the peak porosity Vp during graphitization.

1. Required tools: When removing the old packing root and replacing the new packing root, special tools are required and the gland nut is pre-tightened with a fastener. In addition, it is necessary to use standard safety facilities and comply with relevant safety regulations. Before installation, you must first be familiar with the following equipment: cutting root ring cutting machine, calibration torque wrench or wrench, helmet, internal and external calipers, fasteners lubricant, mirrors, packing remover, cut graphite packing Tools, vernier calipers, etc.

2, cleaning and inspection:

1) Slowly loosen the gland nut of the stuffing box to release any residual pressure in the packing assembly;

2) Remove all old packing and thoroughly clean the shaft/rod stuffing box;

3) Check the shaft/rod for corrosion, dents, scratches or excessive wear;

4) Check other parts for burrs, cracks, and wear. They will reduce the life of graphite packing;

5) Check the stuffing box for excessive clearance and shaft/rod eccentricity;

6) Replace parts with major defects;

7) Check the old packing as a basis for failure analysis to find out why the packing has failed early.

3. Measure and record the diameter of the shaft/rod, the bore diameter and the depth of the stuffing box, and record the distance from the bottom to the top of the stuffing box when the ring is sealed with water.

4, choose packing:

1) Ensure that the selected packing should meet the operating conditions required by the system and equipment;

2) Based on the measurement record, calculate the graphite packing cross-sectional area and the number of packing ring required;

3) Inspect the packing to ensure it is free of defects;

4) Before installation, make sure the equipment and packing are clean.

5. Preparation of Packing Rings 1) Braided Packing Wrap the packing on a suitable sized shaft, or use a calibrated packing cutter; cut the packings neatly (but square) or mitered (as required) 30-45 degrees), cut one ring at a time, and check whether the dimensions are correct with the shaft or valve stem.

2) Molded packing ensures that the ring size is precisely matched to the shaft or stem and, if necessary, cuts the packing ring according to the packing manufacturer's operating instructions or requirements.

6. Install graphite packings. Carefully install one packing ring at a time. Place each ring around the shaft or stem. Before installing the next ring, make sure that the ring is fully seated in the stuffing box. Next The rings should be staggered, at least 90 degrees apart, and generally require 120 degrees. After the first ring is installed, tighten the nut by hand and press the cover evenly. If there is a water seal ring, check its distance from the top of the stuffing box. At the same time ensure that the shaft or valve stem can rotate freely.

7, adjust the packing:

a. Valve Packing Consult with the manufacturer of the packing or the company's technical department about torque regulations or percentage compression. Tighten the gland nut as follows:

1) Apply torque to the gland nut to 30% of full torque or the percentage of compression of the party;

(2) repeatedly open and close the valve several times, when the valve is in the closed position, apply all the torque;

(3) Repeat step 2) 3 or 4 times. b. Pump packing:

(1) Continue to tighten the gland nut by hand;

(2) After opening the pump, adjust the gland nut, allowing a little more leakage at this time;

(3) Slowly tighten the gland nut and gradually reduce leakage until the leak reaches an acceptable level;

(4) If the leakage suddenly stops, tighten the cap nut and re-adjust to prevent the packing from overheating;

(5) Adjust the leak rate to a stable state.

7. Re-tighten and replace the graphite packing. After several hours of operation, check the adjustment of the cover and tighten it if necessary. When the cover cannot be further adjusted, the packing must be replaced.

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