Power plant products |
New-geometry metallic sealing rings can cut valve leakage
Results from a new test programme have shown that certain metallic sealing ring gap geometries can dramatically reduce leakage by factors of up to twenty-five, challenging long held assumptions about metallic sealing ring performance in valves that must withstand high temperatures beyond the limits of polymer seals. While metallic rings have been essential for decades in high temperature environments such as gas and steam turbines, the industry has accepted that they leak more than polymer alternatives. The new data illustrates that geometry, not just material, can be the key to unlocking better sealing performance. In an extensive test programme, engineers at Cross Manufacturing used a purpose built 2.5 inch modular test rig to compare the leakage characteristics of different metallic ring designs used in cage guided globe valves and similar systems. The study put four gap configurations head to head, along with variations in ring width, ring packs and surface finish, to determine which variables genuinely influence leakage and which have only marginal impact.
scarf cut step gap ring – also delivered strong results, achieving Class IV performance when paired with finer surface finishes. For applications where groove width limits the use of dual ring arrangements, the test suggests this could represent a meaningful improvement.
New test rig
The results showed that a pair of side-cut step-gap rings almost eliminated direct leakage paths, achieving performance roughly twenty- five times better than the standard butt gap ring configuration widely used in high temperature valves today. The pairing met ANSI FCI 70 2 Class IV leakage levels, a benchmark many valve makers aim for but have great difficulty achieving with metallic seals. A second configuration – a
To run the tests, Cross engineers developed a new modular static test rig and control system, with switchable mass flowmeters and high accuracy pressure sensors. Repeatability tests showed less than 5% variation over ten full strip down cycles, an unusually high level of consistency for metallic sealing tests. The rig’s modularity means new geometries, materials and manufacturing tolerances can be evaluated in future studies. A Cross Manufacturing spokesman commented: “With valves increasingly used in advanced high temperature applications where leakage limits are becoming ever tighter, the study raises the question whether the industry is underestimating what metallic rings can achieve.”
GameChange BOS transformers finish short-circuit tests
GameChange BOS, the transformer division of GameChange Energy Technologies, has successfully completed dynamic short circuit type testing of its high-capacity, multi-winding transformers. The rigorous type test, conducted at the Central Power Research Institute in Bhopal, India, validates the company’s manufacturing readiness to supply grid- compliant, resilient transformers for renewable energy and utility applications worldwide. The company has the capacity for transformers up to 138 kV and 50 MVA, with a planned expansion to 345 kV and 300 MVA. The destructive short- circuit test assesses a transformer’s ability to
withstand dynamic mechanical impacts due to short circuits, and extreme electrical conditions that can occur during grid disturbances. GameChange BOS’s 17.6 MVA, 5-winding Inverter Duty Transformer successfully endured nine consecutive asymmetrical shots at 100% of requested current for 0.25 seconds each, confirming its resilience against the types of severe electrical events that can cause catastrophic equipment failure.
Conducted in accordance with International Electrotechnical Commission (IEC) standards, the comprehensive testing programme included routine measurements as per IEC 60076-1,
performed both before and after short-circuit tests to verify electrical performance integrity; short-circuit tests per IEC 60076-5, utilising a three-phase supply on the high-voltage side with pre-set short-circuit on the low-voltage (LV) side; dielectric routine testing per IEC 60076- 3, including applied voltage (AV) and induced voltage withstand (IVW) tests conducted before and after short-circuit events; sound level determination in no-load conditions per IEC 60076-10 and physical inspection following complete transformer un-tanking to visually examine internal active parts, in compliance with IEC 60076-5 Clause 4.2.7.4a.
Optimising solar layout decision-making
US-based software company PVFARM has begun beta testing of its new tool, currently referred to as ‘RE PILOT‘, for optimising solar layout decision-making. The tool, currently under development, automates evaluation processes for solar layouts by quickly analysing thousands of potential site configurations based on parameters such as pitch distance, direct current/alternating current ratio and racking system. It aims to reduce the time required for layout analysis from hours to minutes, replacing manual and spreadsheet-based workflows. According to PVFARM, RE PILOT targets developers with limited engineering resources and those who have traditionally dedicated
analysis, which can lead to duplicated work and delays when engineering adjustments become necessary.
Image credit: 2026 PVFAR.
significant effort to determining optimal site layouts. Industry participants often face fragmented design methods, using multiple software tools for satellite imagery, energy simulation, civil modelling and financial
40 | April 2026 |
www.modernpowersystems.com
The layout phase remains critical in ensuring conceptual designs align with construction constraints as decisions made at this stage affect earthworks, cable routing, inverter loading, shading losses and long-term project returns. PVFARM is currently inviting applications for the RE PILOT beta test, which is set to commence in late April this year. Participants will have the chance to offer direct feedback that will influence the final version of the tool, which aims to enhance the speed and quality standards of solar site layout assessment and selection.
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