Packing Installation Guide

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Packaging Installation Guide I. Preparations before installing the sealing packing Removing the old packing and checking the packing box are key steps in the preliminary installation preparations. Before installing new packing, remove the old packing completely using specialized tools, and clean the packing box thoroughly. Check all parts of the packing box for any damage or eccentricity; damaged valve stems, shaft sleeves, and packing boxes can all affect the performance of the packing. Check whether other components can still be used. Replace all damaged parts. II. Selection of appropriate packing for sealing – When choosing packing, two things must be taken into consideration. The operating conditions must be compatible with the performance of the packing. The packing that best meets the requirements can be selected based on relevant technical data. If you have any questions, please consult the sales representative. The size of the packing must be selected correctly according to the sealing requirements. To determine the cross-section, use the following formula: Cross-section = (diameter of the stuffing box – diameter of the valve stem) / 2. Devices that are damaged may require gaskets with a slightly larger cross-section in order to compensate for the damage. III. Cutting and installation of sealing packings: Select an appropriate packing, and use cutting equipment to precisely cut the packing ring to the desired length. If no such cutting equipment is available, the length of the packing can be calculated using the formula L = (shaft diameter d + packing width s) × 1.07 × √2. Generally, on rotating shafts, a 90° cut is made, while on valves, a 45° cut is used. Never try to determine the length by using the tightly wound packing box. Alternatively, wrap the packing around a tube with the same O.D. as the valve stem and press it tightly, but do not stretch the packing. It is then cut into sample rings, and checked to ensure that it can properly fill the space and that there are no gaps at its joints. Then, the sample ring can be used as a standard to cut other packing rings. If these finished products are created in a flat shape, and if the packing is soft or prone to deformation, a small strip can be made based on the sample ring, and then the remaining packing rings can be fabricated using rope. When gaskets are used in valves, the cross-section of the gasket matches the space available in the valve; it is advisable to use a pre-compressed ring. When used in pumps, the cross-section of the gasket and the space available in the valve (around 0.3mm–0.6mm) create a leakage gap between the shaft and the gasket, which facilitates lubrication and heat dissipation. In reciprocating pumps, guide rings should also be placed at both ends and in the middle of the stuffing box to maintain its concentric motion and to counteract the weight of the plunger. After installing the packing ring, tighten the bolts. To apply a uniform pressure to each nut, it is recommended to use a wrench or a suitable measuring device to tighten the nuts. Note: If the device is leak-free at this time, it may cause the packing to burn. It is recommended to tighten the bolts gradually until the leakage level reaches the allowable range. Install one packing ring at a time, making sure that no dust or other debris is stuck to each packing. If necessary, the packing ring should be lubricated with the same clean lubricating oil used on the valve stem. Install each packing ring at 90° to the adjacent ones. The rings are slowly separated axially, with the radial distance being such that the rings can be fitted onto the shaft; a specialized packing tool is used to secure each packing ring. Once enough packing rings have been installed, the valve should be adjusted until the gland extends to 25% of the packing thickness; for pumps, this figure is 50% of the packing thickness. Seal it with a follower; using a follower can increase the tightness. Please remember that the follower is merely a supplementary element ； It ensures that all packing rings are in the proper position, preventing the packing from shifting. IV. Starting of rotary and reciprocating pumps: Before operation, run the pump under no-load conditions to check for any abnormalities, and then start it officially. Pay close attention to ensure that there is no uneven pressure or excessive tightness that could cause severe leakage or damage to the packing. The key when starting a pump is to ensure that it leaks at the beginning. If the packing is tightened to a leak-free state from the start, it will burn the packing and cause leakage. After installing the packing ring, tighten the bolts and ensure that the cover is properly seated against the surface of the packing box. Once starting to tighten the bolts, make sure that each bolt is subjected to even force. If an external lubrication system is used, it must be ensured to be functioning properly before startup. A high leakage rate is allowed at startup. During this process, the packing is positioned and begins to function. After operating for about 15–30 minutes, tighten the bolts again until the leakage is within the allowable range. The recommended leakage rate is 8-10 points per minute. The tetrafluoroethylene filler should allow for a higher flow rate to dissipate heat and reduce thermal expansion. V. Valve operation: In most cases, the valves are designed to be leak-free. To meet this requirement, a sufficient tightening force on the packing must be applied based on the valve pressure. VI. Installation Guide for Valve Packing 1. Follow the installation guide for pump packing strictly ； 2. Rotate the valve stem back and forth to ensure it rotates smoothly ； 3. Inspect the valves before operation; if any leakage is detected, make appropriate adjustments in accordance with the relevant safety maintenance procedures and the manufacturer’s recommendations.