PSRV Disc Lapping: Hands-On TVET Training with the Kemet Hand 3 Lap Kit
Pressure Safety Relief Valves (PSRVs) are one of the last lines of defence in any pressurised system. When upstream pressure exceeds a safe threshold, a spring-loaded disc lifts off its seat to vent excess pressure, then reseats to restore a leak-tight seal the moment normal conditions return. That reseating performance depends entirely on two mating surfaces: the disc and the seat. If either surface is out of flatness or carries even a few microns of surface damage, the valve can fail to reseal, leak under normal operation, or fail to open when it matters most.
This is why PSRV disc and seat lapping is a core skill in mechanical plant maintenance, and why it formed the centrepiece of a recent industry-education collaboration in Malaysia.
Why Disc and Seat Lapping Matters for PSRVs
A PSRV's ability to hold pressure and reseal reliably comes down to the quality of its sealing surfaces. Lapping is the precision process used to correct flatness and refine surface finish on the disc and seat, ensuring the two surfaces mate cleanly under load. Poor lapping technique, or the wrong abrasive grade, can leave a valve prone to leakage long before it is due for its next scheduled maintenance.
From Classroom to Workshop: Xplore VISTA i-Plus 2026
On 9 September 2026, the Oil & Gas (Mechanical) Technology Division at ADTEC JTM Kampus Batu Pahat hosted the Xplore VISTA i-Plus PETRONAS 2026 programme, giving secondary school students an early, hands-on introduction to Technical and Vocational Education and Training (TVET). The event was officiated by YB Tuan Haji Mohd Yusla bin Ismail, State Assemblyman for Senggarang, with representatives from PETRONAS, the Johor State Education Department and the Batu Pahat District Education Office also taking part.
Around 140 Form 3 students from 24 schools across the Batu Pahat district attended, supported by 36 accompanying teachers and 10 facilitators. Rather than a purely theoretical introduction to the industry, the programme was built around direct exposure to real equipment and real processes, letting students see, understand and physically practise the skills used in industrial maintenance.
As part of this, ADTEC JTM's Mechanical Oil & Gas division introduced students to the internal, spring-loaded components of a PSRV and walked them through the basics of disc lapping using a Kemet Hand 3 Lap Kit, under the guidance of instructors and senior ADTEC students.
Around 140 students from 24 schools across Batu Pahat took part in the PETRONAS Xplore VISTA i-Plus 2026 programme.
The Lapping Process: Three Stages, One Portable Kit
The training reflected the same staged approach used in industrial valve refurbishment. The Kemet Hand 3 Lap Kit is built specifically for this kind of on-site, component-level work, and carries everything needed to take a disc or seat from as-found condition through to a finished sealing surface:
- Stage 1 — Lapping: a 150mm composite lapping plate charged with 25-micron Kemet Diamond Compound removes surface damage and corrects flatness.
- Stage 2 — Preliminary polishing: a second 150mm composite plate with 8-micron diamond compound refines the surface finish.
- Stage 3 — Final polishing: a third plate with 3-micron diamond compound brings the surface to a mirror-like, leak-tight finish.
Each plate sits on an aluminium backing plate with a non-skid facing, and the full kit — plates, three 10g diamond compound sticks, OS lubricating fluid and instructions — packs into a single aluminium case. That portability is exactly what makes it suited to both training environments and genuine field refurbishment, where valves often can't be removed to a workshop.
What the Students Took Away
Working through the process by hand rather than watching a demonstration, participants came away with a grounding in:
- The basic components and operating principles of a PSRV
- The role of the disc and seat as sealing surfaces
- Why surface finish is critical to sealing performance
- The fundamentals of precision lapping
- Mechanical component control during hands-on work
- The link between maintenance quality and pressure safety equipment reliability
- Career pathways within mechanical plant maintenance
For many students, it was their first physical encounter with a process that underpins safety-critical equipment across the oil & gas sector, turning an abstract idea into a tangible one: a disc they lapped themselves, on a plate they controlled themselves.
Students at ADTEC JTM Kampus Batu Pahat learn PSRV disc lapping using the Kemet Hand 3 Lap Kit.
Built for Training and the Field Alike
Programmes like Xplore VISTA i-Plus highlight something Kemet sees constantly in industry: disc and seat lapping is a skill best learned by doing, not just reading about. The same Hand 3 Lap Kit used by ADTEC JTM Kampus Batu Pahat to introduce PSRV maintenance to the next generation is the same kit technicians reach for when refurbishing valves and seals on site, without the delay or expense of full disassembly.
View the Kemet Hand 3 Lap Kit specifications, or contact Kemet to discuss training or on-site lapping applications for your facility.
Event details and photography credit: Oil & Gas (Mechanical) Technology Division, ADTEC JTM Kampus Batu Pahat.
