Across the global valve industry, low-emission packing solutions generally fall into three main structural categories: composite designs (with graphite sandwiched between upper and lower braided rings), fully braided structures, and specially profiled shapes such as V-type or X-type. To further enhance sealing performance and reduce emissions, many manufacturers also apply various surface impregnation treatments to the packing materials.
However, most of these designs and treatments are conceived from the manufacturer’s standpoint, and do not always align with the true operational demands of valve applications in real industrial environments.
Consider, for example, the extreme operating conditions found in Northern Europe. Pipeline media may reach 300°C during daytime operation, then drop to -40°C overnight after shutdown. Under such drastic thermal fluctuations, packing materials are exposed to intense tensile and compressive stress, representing one of the most authentic tests of both sealing principles and manufacturing integrity.
While many packing products can successfully pass ISO 15848-1 type tests across temperature ranges from ambient to 400°C and back, performance often deteriorates during low-temperature transitions (e.g., from ambient down to -50°C).
One key reason lies in the overuse of impregnating emulsions. To achieve lower leakage rates, excessive impregnation is often applied to fill micro-gaps and enhance sealing density. Yet these additives can introduce undesirable thermal behaviors — shrinking at low temperatures and softening at high ones — ultimately compromising sealing stability under dynamic conditions such as those encountered between +300°C and -40°C.
Moreover, many ISO 15848-1 evaluations are conducted in segmented stages, with high-temperature and low-temperature cycles tested separately. This methodology does not fully replicate real-world temperature cycling, creating blind spots that may conceal weaknesses in actual low-emission performance.
Through years of research, testing, and field validation, we have developed a deeper understanding of performance criteria and manufacturing parameters for low-emission graphite packing that more accurately represent real operational needs.
For thermal cycles ranging from +300°C to -40°C, our engineering focus is on achieving an optimal balance between sealing efficiency and thermal adaptability—ensuring both high-temperature resilience and dimensional stability at low temperatures.
We have further advanced our designs through the concept of pressure-responsive adaptability — a structural principle that allows the packing to remain flexible and self-adjusting under varying pressure and temperature, rather than becoming rigid or deformed after repeated thermal cycles.
To us, a truly reliable low-emission graphite packing is not merely a product optimized for laboratory certification. It is a purposefully engineered sealing component designed with responsiveness and adaptability at its core — ensuring safer, more stable, and longer-lasting performance under real-world valve operating conditions.It's important to know about Google SEO to help your website rank higher in search results.