Compression amount of graphite filler
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To what maximum pressure can a 12mm graphite filler be compressed? How is this compression force calculated?
One can only observe closely on-site; tighten it by one or two turns when there is flowing fluid, and loosen it by one or two turns when smoking occurs – it depends on the pressure of the medium.
Number of valve packing rings. Soft filler: 4–10 turns when PN ≤ 2.5 MPa ； When PN = 4.0–10 MPa, 8–10 turns. Plastic packing: one turn of upper packing, 3–4 turns of middle packing, and a metal packing pad at the bottom. Based on practical experience, tighten while observing.
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Inside the valve’s stuffing box, wave-shaped packing is installed in the upper and lower layers, while flexible graphite packing is used in the middle. Before operation, the union bolts and nuts at the packing gland should be tightened (the compression amount of the packing at the stuffing box should be about 10% of the total height of the packing) to prevent the packing from being damaged by the medium during operation and causing severe leaks. If bubbling or slight leakage is observed at the stuffing box during operation, the union bolts and nuts at the packing gland must be tightened again until no leakage occurs.