Valve Overhaul
Overhaul, testing and recertification of industrial valves — restoring tight shutoff and documented reliability to plant fluid systems.
Why This
Matters
The wrong specification here doesn't show up on day one — it shows up as downtime, contamination or wasted energy later.
Asset protection
Passing valves erode their own trim continuously — early overhaul is a service item; late overhaul is a replacement, and the gap between the two is entirely a function of inspection interval.
Process integrity
Isolation that does not isolate is a safety issue: leaking block valves undermine every permit and every maintenance task downstream that relies on that isolation holding.
Operational efficiency
Passing control and relief valves bleed product and energy invisibly, around the clock — losses that never appear on a shift log but accumulate over a full run length.
Where It's
Used
Valve Overhaul in service — sector by sector, application by application.
Oil & Gas
Isolation, control and relief valve overhaul during shutdowns.
View Oil & GasPower & Energy
Steam and feedwater valve reconditioning and testing.
View Power & EnergyPetrochemicals
Process valve campaigns aligned with turnarounds.
View PetrochemicalsWater & Desalination
Large-bore isolation and check valve refurbishment.
View Water & DesalinationMarine & Offshore
Dockside valve overhaul with class documentation.
View Marine & OffshoreChemical Manufacturing
Alloy valve reconditioning for corrosive services.
View Chemical ManufacturingHow It Works
Valve overhaul returns each unit to as-new sealing and operation through machining-grade reconditioning and certified testing.
- 1
As-found testing records seat leakage and operation before strip-down.
- 2
Disassembly, cleaning and dimensional inspection of body, trim and stem.
- 3
Seats and discs are machined and lapped to restore sealing surfaces; stems repacked, gaskets renewed.
- 4
Reassembly with controlled torques, then hydrostatic body and seat testing to API 598.
- 5
PSVs are set, tested and sealed with calibration certificates.
Configurations
We Offer
Every variant Dolphin builds — each engineered for a specific duty, not a catalogue default.
Isolation Valves (Gate/Ball/Butterfly)
- Best For
- Restoring tight shutoff for safe isolation.
- Advantage
- Machining and lapping to seat-leakage class, verified by test.
Pressure Relief Valves
- Best For
- Statutory testing and recertification.
- Advantage
- Set-pressure testing with sealed, certificated results.
Check & Control Valves
- Best For
- Flow assurance and control performance.
- Advantage
- Trim reconditioning restores characteristic and prevents reverse-flow damage.
How to
Choose
| Criterion | Guidance |
|---|---|
| As-found leakage | Seat test results decide reconditioning depth — lapping, machining or trim replacement. |
| Service criticality | Safety and isolation-critical valves get priority scope and full certification. |
| Statutory schedule | PSV recertification intervals drive campaign timing alongside turnarounds. |
| Location | Workshop overhaul for depth; site machining for large-bore valves that cannot move. |
Key
Benefits
What sets valve overhaul from Dolphin apart, in specific and measurable terms.
- 01
Verified tight shutoff
Restored and verified by API 598 seat testing.
- 02
Certified PSV testing
Testing and sealing with calibration certificates.
- 03
Turnaround-aligned campaigns
Execution scheduled to match turnaround windows.
- 04
On-site machining
For large-bore and welded-in valves.
- 05
As-found / as-left records
Documented condition per valve.
- 06
One contractor, one window
Valves and exchangers covered in the same scope.
Technical
Specifications
Design codes, materials and testing scope confirmed for every valve overhaul order.
| Valve types | Gate · globe · check · ball · butterfly · PSV/PRV |
| Size range | ½" to 48"+ |
| Testing | API 598 body & seat · PSV set-pressure certification |
| Capability | Machining · lapping · repacking · trim replacement |
| Execution | Mussafah workshop · site crews · TA campaigns |
Why Dolphin for
Valve Overhaul
Combined-scope economics
Valves and exchangers overhauled under one mobilisation cut vendor count and window interfaces.
Certified test capability
API 598 and PSV set-pressure testing with sealed certification at Mussafah.
Machining depth in-house
Seat and body machining in our workshop rescues valves others would scrap.
Frequently Asked Questions
Gate, globe, check, ball, butterfly and pressure-relief valves from ½" to beyond 48", in carbon steel through exotic alloys.
Yes — set-pressure testing, sealing and calibration certificates per statutory requirements.
Large-bore and welded-in valves can be machined and reconditioned in place by our site crews.
Hydrostatic body test and seat-leakage test to API 598, documented per valve.
Yes — as-found and as-left condition, work performed, and test results per valve tag.
Yes — valve scope is routinely executed alongside our exchanger scope in the same window.
Yes — trim, packing and gaskets supplied or manufactured, with material certification.
Share your valve list and window dates via the RFQ form; we return scope, pricing and logistics.
Talk to an Engineer About Valve Overhaul
Send your duty requirements or existing datasheet — our engineers will confirm the right configuration and get you a quote.