Hydraulically operated valves pair a valve with a hydraulic actuator and a hydraulic power unit (HPU) so the package delivers the highest force density of any drive method - and, with the right configuration, a defined fail position that survives loss of plant power. The product word names the drive method, so the actuator, not the valve body, decides whether the valve strokes on demand.
The most common reason a hydraulically operated valve fails to actuate when it matters is not the valve body - it is an actuator sized to the average case and a fail position left blank. A double-acting hydraulic unit with no accumulator simply holds its last position when hydraulic supply is lost; only a spring- or accumulator-backed design moves to a defined fail-closed or fail-open. Above roughly 10,000 N·m rotary or 50 kN linear, or anywhere a defined fail position must ride through a power loss and an HPU already exists, hydraulic actuation is usually the right call; below those, pneumatic or electric normally costs less and is simpler.
GNEE supplies the complete package - valve, scotch-yoke or rack-and-pinion or linear hydraulic actuator, and HPU - built to API 600/602/623/608/609 and API 6D bodies with ASME B16.34 pressure-temperature envelopes, and actuators specified per MSS SP-135, ISO 5210 and ISO 5211. Send your valve type, differential pressure and required fail action for a matched quote.
Design Features
- Local & Remote on/off servie options
- Hydraulic Power Packs (Individual or central units)
- Emergency operation by hand pump
- Nitrogen Accumulator for emergency operation
- Solar powered electro-hydraulic actuation systems
- Fireproof configuration
Specifications
| Parameter | Capability |
|---|---|
| Valve types | Ball, butterfly, gate, globe (quarter-turn, multi-turn, linear) |
| Nominal size (DN) | DN 50–1500 (2"–60") ball; DN 80–1800 (3"–72") butterfly; DN 50–1200 (2"–48") gate |
| Pressure class | ASME B16.34 Class 150–2500; API 6D up to Class 600/900 pipeline |
| Body material | WCB, LCB, LCC, CF8M (316), WC6/9, duplex on request |
| Actuator type | Scotch yoke, rack-and-pinion, linear cylinder, vane |
| Torque / thrust | Up to 300,000+ N·m rotary; 50 kN–several MN linear (F = P × A) |
| Hydraulic supply | 10–250 barg (valve duty); 210–350 bar (cylinder duty) |
| Fail action | Fail-closed, fail-open, or fail-in-place (configuration dependent) |
| Seat leakage | ISO 5208 Rate A (soft) / Rate D (metal); API 598 / EN 12266-1 tested |
| Certification | ISO 9001; SIL 2/3; ATEX / IECEx; API 607 / 6FA fire-safe; third-party inspection available |
| MOQ | 1 set (complete package) |
| Lead time | Stock 7–15 days; engineered / subsea / accumulator 20–35 days |
| Warranty | 18 months actuator, 12 months valve body |
Actuator Mechanism Decoder
When the product word names the drive method, the actuator is the content body. The mechanism sets the torque or thrust profile; the configuration sets the fail behaviour. For a hydraulic actuator vs pneumatic or hydraulic actuator vs electric choice, force density, fail action and available utilities decide - hydraulic wins above roughly 10,000 N·m rotary or 50 kN linear, or where a defined fail position must survive loss of plant power.
Mechanism families
| Mechanism | Motion | Profile | Best fit |
|---|---|---|---|
| Scotch yoke | Quarter-turn | Peak torque at 0° and 90° (symmetric); shaped curve (canted) for modulating | Large ball/butterfly, ESD, pipeline |
| Rack-and-pinion | Quarter-turn | Flatter torque across stroke | Modulating large ball/butterfly |
| Linear cylinder | Multi-turn / linear | Constant high thrust, F = P × A | Gate, globe (rising stem) |
| Vane | Quarter-turn (90–360°) | Compact, limited-angle | Swing drives, small valve duty |
Fail-safe behaviour - three configurations
Hydraulic actuator fail safe behaviour is a process-safety decision, settled from a hazard or SIL study - not by convention. The configuration decides what the valve does on loss of hydraulic supply:
| Configuration | Action on supply loss | Stored energy | Use |
|---|---|---|---|
| Double-acting + lock valve | Fail-in-place (holds last position) | None | Pure control duty |
| Spring-return | Fail-closed or fail-open | Spring | Where a safe end position is required |
| Accumulator-backed | Fail-closed/open, 3–5 rapid strokes | Nitrogen-charged oil | Subsea, remote pipeline ESD |
Choose the fail position from the process hazard: fail-closed for hydrocarbon or chemical feed isolation; fail-open for cooling-water or relief paths that must keep flowing. Document the required fail time - some ESD specs demand "closed within 2 seconds," which rules out a slow electric actuator. A fail in place hydraulic actuator (double-acting with lock valve) simply holds position, whereas an accumulator backed hydraulic actuator stores pressurised oil so it can stroke to the fail position - the configuration used for hydraulic actuator for ESD duty where loss of hydraulic supply is the initiating event.
Hydraulic power unit and self-contained architecture
The hydraulic power unit (valve actuator supply) - the hydraulic power unit valve actuator circuit - delivers filtered, pressurised oil: pump, reservoir, accumulator, directional valve and controls. The actuator, HPU, hoses and fittings must share one design pressure with margin above it. Fluid cleanliness matters - specify ISO 4406 19/17/14 for medium-pressure and 18/16/13 for high-pressure (> 200 barg) systems, or SAE AS4059 Class 6. A self contained hydraulic actuator (self-contained) integrates reservoir, compensator, accumulator and controls into one head that bolts to the valve, removing the external HPU and hose run - preferred for remote sites and skids. Gas over oil (gas-over-oil) units use process gas to pressurise hydraulic fluid for remote high-pressure natural-gas lines.
Valve & Actuator Package
Motion type decides the actuator family: hydraulic operated ball valves and hydraulic operated butterfly valves use quarter-turn rotary actuators, while hydraulic operated gate valves and globe valves use linear or multi-turn cylinders. The table below maps each valve type to its typical package.
| Valve type | DN range | Body standard | Torque / thrust | Fail action | Typical service |
|---|---|---|---|---|---|
| Ball | DN 50–1500 (2"–60") | API 608 / ISO 17292; API 6D pipeline | Up to 300,000+ N·m | FC / FO / FI | Pipeline, ESD, DBB isolation |
| Butterfly | DN 80–1800 (3"–72") | API 609 Cat A/B; EN 593 | Up to 100,000+ N·m | FC / FO / FI | Large-bore low-cost isolation |
| Gate | DN 50–1200 (2"–48") | API 600 / API 602 | Very high thrust (full-ΔP seating) | FC / FO / FI | High-pressure isolation, wellhead |
| Globe | DN 50–600 (2"–24") | API 623 / BS 1873 | High near-constant thrust | FC / FO / FI | Throttling, high-DP control |
Breakaway torque peaks at the closed position from seat friction and differential pressure; reseating torque is the other demand peak. Scotch yoke delivers peak output exactly at both ends of the stroke - which is why it dominates large quarter-turn ESD valves.
Major Component Materials
| Component | Standard material | Optional |
|---|---|---|
| Cylinder / housing | Carbon steel, epoxy painted | Stainless 316L, electroless nickel plated |
| Piston / rack / yoke | Carbon steel | Nickel-plated, stainless |
| Stem coupling | Machined bushing per ISO 5210/5211 | Custom keyed bore |
| Seals | NBR (Buna-N) | Viton, fluorosilicone, perfluoro (per fluid) |
| HPU reservoir | Carbon steel | Stainless, phosphate-ester compatible |
| Hydraulic fluid | Mineral oil ISO VG 32–68 | Water-glycol, phosphate ester (fire-resistant) |
Never pair standard nitrile seals with phosphate-ester (HFD) fluid; match the seal compound to the fire and temperature risk, and set the target ISO 4406 cleanliness code and filtration to maintain it.
Mounting Interface & Stroke
| Item | Standard / value |
|---|---|
| Part-turn mounting | ISO 5211 (F03–F25 flange codes, drive square/keyed bore) |
| Multi-turn mounting | ISO 5210 (flange, threaded or splined drive bushing) |
| Pipeline valve actuator | API 6DX (mounting and sizing for API 6D valves) |
| Hydraulic supply pressure | 10–250 barg (valve); 210–350 bar (cylinder) |
| Full-stroke time | 0.5–5 s (large valves); < 0.5 s for high-speed ESD (Flowserve LHS/LHH class) |
| Position feedback | 4–20 mA / 0–10 V, digital fieldbus, HART |
| Enclosure | IP66 / IP67 (IP68 subsea); ATEX / IECEx solenoids and switches |
ISO 5211 / ISO 5210 only define the interface dimensions - they do not confirm that output torque, stroke direction, travel or valve allowable load are matched. Confirm the full valve-actuator combination against the valve maker's torque/thrust curve at minimum supply pressure.
Applications
Subsea production. Trees and manifolds on deepwater systems, hydraulically actuated through an umbilical; subsea hydraulic valve actuators are the only practical drive beyond 3,000 m water depth.
Pipeline mainline. 24" (600 mm) and larger ball valves on transmission lines where pneumatic or electric torque is uneconomic.
ESD / ESDV. Emergency shutdown valves where a defined fail-closed must stroke within seconds of a trip, with stored energy after HPU loss.
High-pressure gate valves. Wellhead master valves and high-differential-pressure isolation needing very high seating thrust.
Offshore FPSO process. Hazardous-area duty with no ignition source at the actuator (intrinsically safe).
Power and water. Large-bore butterfly and gate isolation on cooling, intake and turbine bypass lines.
Isolation function - DBB, DIB and cavity relief
Hydraulically operated ball valves are the standard platform for double block and bleed (DBB): two seating surfaces with a bleed between them, so the cavity can be vented and verified isolated from both lines. DIB (double isolation and bleed) holds pressure from both sides. For trapped-cavity protection, specify cavity relief - a bleed or relief path so thermal expansion or blocked-in fluid cannot over-pressure the body. Confirm the cavity-relief path before specifying a fully blocked-in (double-isolated) service.
Where hydraulic actuation is not the right choice
| Case | Why not hydraulic | Better choice |
|---|---|---|
| Small-bore, simple on/off utility | HPU cost and piping outweigh benefit | Pneumatic or electric |
| No air or power utility on site | Hydraulic still needs an HPU | Manual with gearbox, or self-contained electro-hydraulic |
| Food / pharma with oil-contamination risk | Mineral oil can contaminate product | Pneumatic (or compatible food-grade fluid) |
| Ultra-precise low-flow throttling | Electric servo holds ±0.1%; hydraulic ±0.5% | Electric modulating actuator |
Quality & Testing
100% shell and seat test. Every package is hydrostatically shell-tested and seat-tested to ISO 5208, API 598 or EN 12266-1 - not a sample.
Seat leakage by ISO 5208. Soft seats to Rate A (zero visible leakage); metal seats typically Rate D (0.1 × DN mm³/s liquid). See the table below.
HPU test and cleanliness. Loop flushed and verified to ISO 4406 19/17/14 (or 18/16/13 high-pressure); filtration documented.
Functional and SIL evidence. Full-stroke and partial-stroke (PST) test; SIL 2/3 documentation per IEC 61508 / IEC 61511 where specified.
Third-party inspection. SGS, TÜV or BV witness and certification available on request.
Seat leakage - ISO 5208 Rate A / Rate D
| Rate | Liquid (mm³/s) | Gas (mm³/s) | Seat type / use |
|---|---|---|---|
| Rate A | No visible leakage | No visible leakage | Soft seat; toxic, flammable, zero-leakage duty (bubble-tight) |
| Rate D | 0.1 × DN | 30 × DN | Metal seat; general industrial isolation |
ISO 5208:2015 defines ten rates (A, AA, B, C, CC, D, E, EE, F, G); the allowable rate is proportional to DN only, not to test pressure. Correction: some suppliers write "Class VI per API 598" for isolation valves. Class VI is a leakage class of ANSI/FCI 70-2 for control valves, not of API 598 - API 598 is a valve inspection-and-testing standard. For isolation valves, specify seat leakage by ISO 5208 Rate (A for soft seats, D for metal seats) or by API 598 acceptance criteria; do not mix the two systems on a datasheet.
Packaging, Lead Time & Payment
Packaging. Plywood cases with internal bracing; stem and actuator protected; desiccant for long storage; valve ends capped.
Marking. Tag with valve tag no., DN/Class, body and seat material, serial no., and actuator data per MSS SP-135.
Lead time. Stock-standard packages 7–15 days; engineered, subsea or accumulator-backed 20–35 days (confirm with specification).
Port & shipping. FOB Tianjin / Shanghai; worldwide delivery.
Payment. T/T and L/C accepted.
Warranty & spares. 18 months actuator, 12 months valve body; spare-parts list (seals, coupling, limit switches, accumulator) supplied.
Send your valve type, body material/grade, seat type, required torque or thrust at differential pressure, hydraulic supply pressure and fluid, fail action and fail time, control signal, and area classification - our technical team will confirm the matched actuator (scotch yoke, rack-and-pinion or linear), HPU scope and interface, and return a quotation with lead time, typically within 24 hours. Contact GNEE today.
Why Source From GNEE
GNEE delivers the valve and actuator as one interfaced package rather than two separate purchases.
One matched package. Valve and hydraulic actuator sized together to your differential pressure and duty - one interface, one responsibility, one data sheet.
Standards discipline. Valve body to API 600/602/623/608/609 and API 6D with ASME B16.34; actuator to MSS SP-135, ISO 5210, ISO 5211 and API 6DX; SIL and ATEX/IECEx where required.
Evidence, not adjectives. 100% shell and seat test reports, EN 10204 3.1 MTR, ISO 4406 cleanliness record, and SIL/ATEX certificates - third-party inspection available.
Fast response. Quote within 24 hours with lead time; OEM/ODM and custom mounting supported.
FAQ
What is a hydraulically operated valve?
A hydraulically operated valve is a complete package: a valve plus a hydraulic actuator that converts pressurised oil into shaft torque (quarter-turn) or stem thrust (multi-turn/linear), supplied by a hydraulic power unit (HPU) with pump, reservoir and accumulator. The drive method is hydraulic, so the actuator and its fail behaviour define how the valve performs - not the valve body alone.
How does a hydraulic valve actuator fail safe?
Fail behaviour depends on the configuration. A double-acting unit with a lock valve holds its last position (fail-in-place) when supply is lost. A spring-return unit drives to a defined fail-closed or fail-open. An accumulator-backed unit stores pressurised oil so it can stroke to the fail position - typically 3 to 5 rapid close operations - even after the HPU loses power, which is the architecture used for subsea and ESD duty.
Hydraulic vs pneumatic vs electric actuator - which should I choose?
Above roughly 10,000 N·m rotary or 50 kN linear, or where a defined fail position must survive loss of plant power and an HPU already exists, hydraulic usually wins. Pneumatic is fastest and lowest-cost for clean on/off duty with an air supply. Electric is cleanest for precise modulating duty where reliable power exists. Conflict order: isolation function first, then pressure/rating, size, then media and temperature.
What is a scotch yoke hydraulic actuator?
A scotch yoke actuator converts linear piston force into rotary torque through a yoke slot. A symmetric yoke gives peak torque at both ends of the 90° stroke - exactly where seated ball and butterfly valves need it (breakaway and reseating). A canted yoke shapes the torque curve for modulating duty. It is the standard mechanism for large quarter-turn ESD and pipeline valves.
How do I size a hydraulic valve actuator?
Match actuator output to valve demand at every stroke point: breakaway (peak, at closed), running, and reseating torque for rotary valves; unseating thrust, packing friction and full-differential-pressure seating thrust for gate valves. Force follows F = P × A - a 100 mm bore cylinder at 200 bar gives about 157 kN. Apply a safety factor of 1.25–1.5 for clean service, up to 2.0 for slurry or critical duty, and verify output at minimum guaranteed supply pressure.
What does MSS SP-135 cover for hydraulic actuators?
MSS SP-135 defines the data the purchaser and supplier exchange for pneumatic and hydraulic actuators - including action on loss of hydraulic supply (close, open or fail-last), supply connection, accumulator cycles and pre-charge, and fluid cleanliness per ISO 4406. It is the actuator data-input standard that should back the valve data sheet, separate from the valve-body standard.
What seat leakage class applies - ISO 5208 Rate A or Rate D?
For isolation valves, specify the seat leakage by ISO 5208. A soft-seated valve is tested to Rate A - no visible leakage (bubble-tight) - for toxic, flammable or zero-leakage duty. A metal-seated valve is typically Rate D: 0.1 × DN mm³/s for liquid, 30 × DN mm³/s for gas. API 598 is a parallel North-American inspection-and-testing standard; 'Class VI per API 598' is not correct - Class VI belongs to ANSI/FCI 70-2 for control valves, not isolation valves.
What is a double block and bleed (DBB) hydraulic valve?
A DBB valve uses two seating surfaces with a bleed between them so the cavity can be vented and verified isolated from both lines - common on hydraulically operated ball valves for ESD and isolation. DIB (double isolation and bleed) holds pressure from both sides. For trapped-cavity protection, specify cavity relief (a bleed or relief path) so thermal expansion or blocked-in fluid cannot over-pressure the body.
Can a hydraulic actuator hold position without power?
Yes. Because hydraulic fluid is nearly incompressible, a hydraulic actuator holds its position under hydraulic lock without energising any brake - even when the pump stops. A double-acting unit with a lock valve stays exactly where it was (fail-in-place); a spring- or accumulator-backed unit moves to its defined fail position. This is why hydraulic is favoured where the valve must not drift during a power or signal outage.
What is a self-contained or subsea hydraulic actuator?
A self-contained (integral) hydraulic actuator builds the reservoir, compensator, accumulator and control valves into one head that bolts to the valve - no external HPU or long hose run. Subsea-rated versions extend the same logic to water depths beyond 3,000 m, driven from surface through an umbilical, which is the standard architecture for subsea tree and manifold gate valves.
What is your MOQ and lead time for hydraulically operated valves?
Minimum order is 1 set (a complete valve-plus-actuator package). Stock-standard packages ship in 7–15 days; engineered or subsea/accumulator-backed packages typically run 20–35 days depending on valve type, actuator size and HPU scope. Confirm the exact lead time with your specification.
What documents and certificates do you provide?
Each package ships with an EN 10204 3.1 material test report (MTR), 100% shell and seat test reports (ISO 5208 / API 598 / EN 12266-1), actuator data sheet per MSS SP-135, and SIL / ATEX / IECEx certificates where specified. Third-party inspection by SGS, TÜV or BV is available on request.
What warranty and spare parts do you offer?
We provide 18 months warranty on the hydraulic actuator and 12 months on the valve body from the date of dispatch, plus a spare-parts list (seals, coupling, limit switches, accumulator) for field service. Warranty covers manufacturing defects; it does not cover wear from fluid contamination outside the agreed ISO 4406 cleanliness code.
Do you support OEM / ODM and custom mounting?
Yes. We supply private-label (OEM/ODM) packages and build to your drawing, including custom ISO 5211 / ISO 5210 mounting kits, stem extensions, special coatings and integrated control panels. Send your valve data sheet and actuator requirements and we return a matched, interfaced proposal.