Maintenance of Ceramic Valves

Ceramic valves are mostly installed in process pipelines under harsh working conditions with complex on-site environments. Once a valve fails, disassembly is cumbersome, troubleshooting and fault location are difficult, and the failure may trigger a series of problems including system commissioning, process integrity, regulating quality and environmental pollution. Therefore, scientific and reasonable use of ceramic valves, implementation of maintenance work and maximizing valve service life are the primary concerns in on-site applications.

Early ceramic regulating valves adopted two-piece construction. Through iterative upgrading, the industry now commonly uses the more reasonable three-piece structure. Three-piece ceramic ball valves are equipped with dual seats delivering double-sealing effect. During type selection, priority should be given to products with inclined transition flow passages, which effectively weaken high-speed fluid impact and reduce erosion damage on ceramic sealing pairs. Below are practical maintenance methods for extending ceramic valve service life.

1. Clean Pipelines to Extend Service Life

Residual welding slag, rust, solidified slag blocks, iron wire, cloth scraps and other debris inside pipelines can easily jam in throttling ports and guiding positions, causing valve blockage, jamming, or even breaking the ceramic valve core. Such failures mostly occur during initial commissioning of new systems and after major equipment overhaul, ranking as the most common ceramic valve failure.

When jamming occurs, disassemble the valve for thorough cleaning to remove all kinds of hard residue. If sealing surfaces are already damaged, lapping repair should be performed. At the same time, open the bottom plug to flush accumulated debris and flush the whole pipeline. Before formal system commissioning, fully open the regulating valve to let medium circulate for a period. After pipeline impurities are completely discharged, switch back to normal operating conditions.

2. Operate with Larger Opening to Extend Life

For initial commissioning of ceramic regulating valves, it is recommended to run at approximately 80% of maximum opening. Erosion and wear caused by pipeline impurities will act on non-sealing areas of the valve core. After pipeline impurities are flushed clean, adjust the regulating valve opening to slightly above normal working opening.

As fluid continuously erodes and consumes the valve core, actual flow capacity increases under the same conditions, and valve opening should be gradually reduced accordingly. This method fully utilizes all working surfaces of the valve core until irreversible damage occurs at the core root and sealing surface, making the core no longer usable.

3. Prioritize Reasonable Valve Structure to Improve Life

Ceramic regulating valves have evolved from early two-piece construction to the current mainstream three-piece structure. The three-piece structure is equipped with dual seats featuring double-sealing characteristics. When selecting ceramic ball valves, prioritize valves with inclined transition flow passages, which buffer the medium, reduce direct fluid impact on ceramic sealing surfaces and alleviate erosion damage.

4. Relocate Damage Positions to Improve Life

In ceramic ball valves, the position directly below the fluid inlet features the highest flow velocity and most severe erosion damage. For three-piece ceramic ball valves, the ceramic ball core can be reversely installed to relocate severely eroded positions to secondary locations, thereby protecting sealing surfaces and throttling working faces of the valve core and seat. One ball core can be re-installed in four orientations, theoretically extending valve service life by up to 4 times.

5. Reasonable Size Selection to Improve Life

During type selection, calculate the accurate flow coefficient using the CV value formula and match an appropriate valve bore. Under the same flow rate, smaller valve bore results in faster fluid velocity and more severe erosion on valve cores and sealing components. On the premise that valve regulating stroke can satisfy process requirements, appropriately enlarge valve bore to reduce medium velocity and alleviate wear.

Ceramic valves inherently feature wear and corrosion resistance material advantages, but actual service cycles are affected by multiple factors including selection matching, medium conditions and operation and maintenance. Standardized type selection combined with regular maintenance is the key to fully realizing the performance advantages of ceramic valves.