Description
API 6A Hydraulic Flat Gate Valve for Wellhead and Christmas Tree Service
SGPE supplies API 6A Hydraulic Flat Gate Valves for oil and gas wellheads, Christmas trees, production trees, surface test trees and related high-pressure surface equipment.
Also known as a hydraulic wellhead gate valve, hydraulic slab gate valve or hydraulic actuated gate valve, this valve uses hydraulic force to move a flat gate between two seat assemblies. When fully open, the gate port aligns with the body bore and creates a straight through-conduit flow path. During closing, the solid gate section moves across the bore and isolates well pressure.
Standard configurations cover nominal sizes from 1 13/16 in. to 7 1/16 in. and working pressures from 2,000 psi to 15,000 psi. Selected 20,000 psi requirements can be reviewed separately when the size, minimum bore, end connection, material class and qualified design scope support the application.
Available configurations include forged or cast bodies, metal-to-metal slab gates, rising or non-rising stems, double-acting hydraulic actuators and spring-return fail-safe actuators. Optional equipment includes manual overrides, local position indicators, limit switches, remote feedback devices, sour-service trims, erosion-resistant hardfacing and corrosion-resistant overlays.
Product Short Description
SGPE API 6A Hydraulic Flat Gate Valves provide full-bore pressure isolation for wellheads, Christmas trees, surface test trees and wellhead safety systems.
Available options include forged bodies, metal-to-metal slab gates, flanged or studded API 6A connections, double-acting actuators, fail-safe-close actuators and NACE sour-service trims.
Each valve is selected according to the minimum bore, working pressure, process fluid, end connection, material class, temperature rating, PSL, PR and available hydraulic control pressure.
General Product Specifications
| Parameter | Available Range or Configuration |
|---|---|
| Product Name | API 6A Hydraulic Flat Gate Valve |
| Alternative Names | Hydraulic wellhead gate valve, hydraulic slab gate valve, hydraulic actuated gate valve |
| Nominal Size | 1 13/16 in. to 7 1/16 in. |
| Standard Working Pressure | 2,000 psi to 15,000 psi |
| Selected 20K Configuration | Subject to separate engineering and qualification review |
| Gate Design | Flat gate / slab gate |
| Bore Arrangement | Full bore / full opening / through conduit |
| Primary Sealing | Metal-to-metal gate-to-seat sealing |
| Pressure Direction | Bidirectional where supported by the approved seat design |
| Body Construction | Forged or cast |
| Body Material | Qualified low-alloy steel selected for the approved API 6A design |
| Stem Arrangement | Rising stem or non-rising stem |
| Main Operation | Hydraulic |
| Actuator Options | Double-acting, fail-safe-close or fail-safe-open |
| Backup Operation | Manual override available |
| End Connections | Flanged, studded, hub or project-specific connection |
| Material Class | Selected according to the valve design and service conditions |
| Product Specification Level | PSL 1, PSL 2, PSL 3, PSL 3G or PSL 4 |
| Performance Requirement | PR1 or PR2 |
| Temperature Rating | Selected according to the applicable API 6A temperature requirements |
| Sour Service | NACE MR0175/ISO 15156 configuration available |
| Main Standard | API Spec 6A, applicable edition and addenda |
| Typical Applications | Wellheads, Christmas trees, production trees, surface test trees and safety systems |
The selected valve model determines the exact minimum bore, face-to-face dimension, unit weight, actuator piston area, hydraulic displacement and operating time. These values are confirmed in the approved technical data sheet.
API 6A Hydraulic Gate Valve Applications
API 6A Hydraulic Flat Gate Valves provide pressure isolation during drilling, completion, production, workover and well testing operations.
On a Christmas tree, the valve may serve as a master valve, wing valve, swab valve or flowline isolation valve. Hydraulic actuation allows personnel to control the valve from a local panel or remote control station while reducing repeated manual operation.
Drilling and completion wellheads may use hydraulic wellhead gate valves where the operating program requires remote isolation or frequent cycling. The same basic design can support production trees, surface test trees, well testing skids, workover packages, flowback systems and selected well intervention equipment.
Water injection and gas injection wellheads also use hydraulic slab gate valves. For these duties, the valve body, internal trim, stem packing and actuator must match the injected fluid, differential pressure, operating temperature and expected number of cycles.
Spring-return actuators suit valves connected to wellhead safety systems. They can integrate with a surface safety or emergency shutdown system when the approved control philosophy requires remote well isolation.
Replacement projects require a separate compatibility review. The existing valve bore, face-to-face length, ring groove, stem arrangement, actuator function and hydraulic control pressure must match the proposed replacement.
Why Use Hydraulic Actuation?
Large-bore and high-pressure wellhead valves can require considerable operating force. A hydraulic actuator supplies controlled linear force throughout the valve stroke and reduces manual effort.
Hydraulic operation also allows the valve to connect with a hydraulic power unit, wellhead control panel or emergency shutdown circuit. Operators can open or close the valve from a safer location, while switches or sensors report the valve position.
A double-acting actuator uses hydraulic pressure in both directions. It provides positive opening and closing control while the hydraulic supply remains available. However, it has no built-in spring-return position. The actuator and hydraulic circuit determine its response after pressure loss.
A fail-safe actuator combines hydraulic pressure with stored spring energy. When control pressure falls, the spring moves the gate toward the specified safe position. Depending on the operating philosophy, the project may require fail-safe-close or fail-safe-open operation.
Correct actuator sizing remains essential. The actuator must overcome differential pressure, gate friction, seat loading, stem-packing resistance and other forces present during the operating cycle.
How an API 6A Hydraulic Flat Gate Valve Works
Hydraulic fluid enters the actuator cylinder and moves the piston. The piston transfers linear force through the stem to the flat gate.
The gate contains a circular opening. In the fully open position, this opening aligns with the body bore and creates a straight flow path.
As the actuator moves the gate toward the closed position, the solid gate section enters the bore. It then moves between the seat assemblies and blocks the flow path. Precision-machined metal surfaces on the gate and seats form the main pressure barrier.
| Actuator Type | Opening Method | Closing Method | Typical Function |
| Double-Acting Hydraulic | Hydraulic pressure | Hydraulic pressure | Positive hydraulic control in both directions |
| Fail-Safe-Close | Hydraulic pressure | Stored spring force | Wellhead safety and emergency shutdown duties |
| Fail-Safe-Open | Stored spring force | Hydraulic pressure | Selected circulation or process duties |
| Hydraulic with Manual Override | Hydraulic pressure | Hydraulic pressure or spring force | Backup local operation |
Mechanical indicators, limit switches, proximity sensors and remote position transmitters are available for selected actuator configurations.
A double-acting actuator does not automatically remain in a guaranteed position after hydraulic pressure loss. Internal leakage, external loading, control-valve position and circuit design can affect the final response. The approved hydraulic schematic defines the actual operating behavior.
Flat Gate Valve, Slab Gate Valve and Expanding Gate Valve
Flat gate valve and slab gate valve usually describe the same parallel-gate construction. The valve uses a single flat gate with two sealing faces. Its circular opening aligns with the body bore when the valve is fully open.
An expanding gate valve uses a gate and an expanding segment. Near the end of the opening or closing stroke, the mechanism pushes these components outward against the seats.
The two designs use different internal components, sealing principles and operating forces. They are therefore not directly interchangeable.
This page covers the API 6A Hydraulic Flat Gate Valve with a flat or slab gate. The quotation and technical data sheet identify the final gate construction.
Main Design Features
API 6A Wellhead Valve Configuration
The valve is configured for wellhead and Christmas tree service according to the applicable API Spec 6A requirements.
The project specification identifies the nominal size, minimum bore, working pressure and end connection. It also defines the material class, temperature rating, PSL and PR requirement.
The technical data sheet confirms the stem arrangement, actuator function, hydraulic pressure, fail-safe position and sour-service requirements. It also defines the inspection, testing and documentation scope.
API Monogram supply applies only when the quotation, purchase order and certification package specifically confirm the requirement and applicable licensed scope.
Forged or Cast Valve Body
Forged and cast valve bodies suit different operating conditions.
Forged API 6A gate valves are commonly selected for high-pressure, offshore, drilling and sour-service applications. A qualified forging and heat-treatment process provides controlled mechanical properties for the selected valve design.
Cast bodies can suit selected standard wellhead and production-tree duties. The working pressure, material class, PSL and required nondestructive examination determine whether cast construction is appropriate.
The process fluid, pressure and temperature control the final material selection. H2S partial pressure, CO2, chlorides, produced water, sand content and hardness restrictions can also affect the body, gate, seats, stem, hardfacing and corrosion-resistant overlay.
Full-Bore Through-Conduit Flow Path
When fully open, the gate port aligns with the body bore. This full-bore arrangement reduces internal restriction and limits turbulence.
The straight flow path lowers the risk of solids collecting around a restricted opening. It also keeps the primary gate sealing surfaces away from the direct flow stream during normal open operation.
A compatible minimum bore can allow wireline, slickline, coiled tubing and other intervention tools to pass through the valve. However, nominal valve size does not always equal the exact through bore. Buyers should state the required drift diameter or minimum bore in the inquiry.
The valve should operate in the fully open or fully closed position. A choke valve or another suitable flow-control valve should regulate pressure and flow rate.
Metal-to-Metal Gate and Seat Sealing
Precision-machined metal surfaces form the primary sealing interface between the gate and seats.
General oil and gas service may use stainless steel or hardfaced sealing surfaces. High differential pressure and frequent cycling can require harder and more wear-resistant trim.
Sand-producing wells need additional erosion resistance. Depending on the operating conditions, the design may use tungsten carbide, cobalt-alloy hardfacing or another qualified coating.
Sour or corrosive service can require controlled-hardness materials, stainless steel trim, nickel-alloy components or corrosion-resistant overlay. Selected wetted areas can use Inconel 625 overlay when supported by the corrosion assessment.
| Service Condition | Typical Material or Trim Consideration |
| General Oil and Gas Service | Stainless steel or hardfaced gate and seat surfaces |
| High Differential Pressure | High-hardness sealing surfaces and controlled seat loading |
| Sand-Producing Well | Erosion-resistant hardfacing or tungsten carbide |
| Sour Service | Controlled materials and hardness according to NACE MR0175/ISO 15156 |
| Corrosive Fluid | CRA trim or nickel-alloy overlay |
| Frequent Operating Cycles | Wear-resistant gate, seat and stem materials |
| Low-Temperature Service | Qualified body material, seals, lubricant and hydraulic fluid |
| High-Temperature Service | Suitable packing, actuator seals, lubricant and pressure review |
One trim configuration cannot suit every well environment. The final material combination must match the process fluid, operating pressure, temperature and expected service conditions.
Pressure-Assisted Seat Performance
The seat system can combine mechanical preload with pressure-assisted sealing.
Springs or other preload components maintain gate-to-seat contact at low pressure. As differential pressure increases, line pressure supports the sealing action.
This arrangement supports low-pressure testing, high-pressure testing, production, well shut-in, workover and well testing operations.
Selected hydraulic slab gate valves provide bidirectional pressure isolation. However, the seat arrangement controls the preferred pressure direction, body-cavity behavior and pressure-relief function. These details appear in the approved drawing and operating manual.
Rising and Non-Rising Stem Designs
A rising stem moves vertically with the gate. Its visible movement provides a direct indication of valve travel. This configuration suits accessible wellheads and Christmas trees with sufficient vertical clearance.
A non-rising stem reduces the installed height. It suits compact tree layouts, skid-mounted packages and offshore equipment where space is limited.
Non-rising designs may use a mechanical indicator, limit switch or proximity sensor to show valve position. Remote feedback can also connect the valve to a wellhead control panel.
Body-to-Bonnet and Stem Sealing
The body-to-bonnet connection forms part of the main pressure boundary. Depending on the valve model, it can use a metal ring gasket, pressure-energized metal seal or another qualified sealing arrangement.
Stem packing controls external leakage during valve movement. Options include Chevron-style packing, non-elastomeric packing and temperature-specific sealing systems. Selected models can also include a packing injection connection.
A metal-to-metal backseat may provide a secondary stem sealing interface. It does not replace proper isolation. Personnel must isolate and depressurize the valve before opening pressure-containing parts unless a manufacturer-approved procedure specifically permits a limited stem-seal operation.
Lubrication and Serviceable Components
Lubrication fittings allow technicians to introduce an approved lubricant into designated valve areas. Correct lubrication reduces friction, protects internal surfaces and supports stable operating force.
Selected models include an emergency sealant fitting. Sealant can provide temporary assistance after a sealing problem develops, but it cannot repair a damaged gate, seat or packing system. The valve should undergo inspection and repair after emergency sealant use.
The gate, seats, stem, packing and actuator seals use a maintainable construction. Before internal service, technicians must isolate pressure on both sides, drain trapped fluid, depressurize the body cavity and disconnect hydraulic energy.
Hydraulic Actuator Selection
The hydraulic actuator must match the valve size, maximum differential pressure, available hydraulic supply and required operating force.
The selection review also considers opening and closing time, hydraulic fluid, control-port connection, manual override and position-feedback requirements.
For a fail-safe actuator, the spring must move the valve under the specified worst-case condition. For a double-acting actuator, the control circuit must provide sufficient pressure and flow in both directions.
For an accurate actuator review, the buyer should provide the minimum, normal and maximum hydraulic supply pressure together with the hydraulic fluid type and the minimum and maximum ambient temperatures. The inquiry should also state the required opening and closing time, the required double-acting or fail-safe function, and the control-port size, thread and orientation.
Manual override and position-feedback requirements should be identified at the quotation stage. The technical team also needs to know whether the valve will be installed on a land wellhead, offshore tree, skid-mounted package or another compact system, because the installation affects the actuator seals, coatings, hydraulic tubing and control arrangement.
The approved data sheet confirms the actuator control pressure, hydraulic displacement, port connection and estimated operating time.
Pressure and Size Selection
| Selection Group | Nominal Size | Working Pressure | Selection Notes |
| Compact Wellhead Valve | 1 13/16 in. to 2 9/16 in. | 2,000 to 15,000 psi | Common for master, wing, swab and tree outlet positions |
| Medium-Bore Valve | 3 1/16 in. to 4 1/16 in. | 2,000 to 15,000 psi | Requires review of bore, connection and actuator force |
| Large-Bore Valve | 5 1/8 in. to 7 1/16 in. | Model-dependent, up to 15,000 psi | Requires body, flange and actuator review |
| Selected 20K Valve | Project-specific size | 20,000 psi | Requires separate design and qualification confirmation |
| Fail-Safe Wellhead Valve | Project-specific | Based on selected valve | Requires actuator and shutdown calculation |
| Replacement Gate Valve | Existing equipment dimensions | Based on existing equipment | Requires dimensional and functional review |
Not every nominal size is available at every pressure rating. The final combination depends on the body design, minimum bore, end connection, material class, PSL and actuator.
Common RFQs include 2 1/16 in. 5K and 10K hydraulic gate valves, 2 9/16 in. 10K Christmas tree gate valves and 3 1/16 in. 10K hydraulic wellhead valves. Projects may also request fail-safe-close wellhead valves or selected 15K hydraulic actuated gate valves.
These descriptions identify only the general valve type. A complete quotation also requires the minimum bore, end connection, material class, temperature rating, PSL, PR and actuator function.
API 6A Material Class and Sour-Service Selection
API 6A material classes are selected according to the approved valve design and actual service conditions. Availability of AA, BB, CC, DD, EE, FF or HH depends on the body, trim, manufacturing route and qualified product scope.
These classes do not form a simple scale from low to high corrosion resistance. They define requirements for specific pressure-containing, pressure-controlling and fluid-contact components.
H2S partial pressure affects hardness limits and sulfide stress cracking controls. CO2, chlorides and produced water affect the corrosion assessment. Sand content can require harder or more erosion-resistant sealing surfaces.
Temperature also influences the body material, stem packing, actuator seals, hydraulic fluid and lubricant. Severe service may require stainless steel trim, nickel-alloy components, corrosion-resistant overlay or tungsten carbide hardfacing.
For sour-service projects, the buyer should provide the H2S partial pressure, CO2 content, chloride concentration, produced-water data and complete operating temperature range.
The final valve configuration must meet the applicable API 6A and NACE MR0175/ISO 15156 requirements.
End Connection Options
| End Arrangement | Typical Application |
| Flanged × Flanged | Standard wellhead and Christmas tree assembly |
| Flanged × Studded | Compact tree or block integration |
| Studded × Studded | Reduced installed height |
| API 6B Flange | Selected low- and medium-pressure connections |
| API 6BX Flange | High-pressure ring-joint connection |
| Clamp or Hub Connection | Compact high-pressure equipment package |
| Special Block Body | Integrated tree, manifold or equipment assembly |
| Project-Specific Connection | Replacement or OEM-compatible configuration |
Before production, the technical team confirms the connection size, pressure rating, flange or hub type, ring groove, bore diameter, stud pattern and face-to-face dimension.
Counter flanges, studs, nuts and API ring gaskets can form part of the supply scope.
Inspection, Testing and Documentation
Inspection and testing follow the approved purchase order, quality plan and applicable API 6A requirements.
Material verification checks chemical composition, mechanical properties and traceability. Heat-treatment records and hardness results confirm compliance for pressure-containing and pressure-controlling parts.
Dimensional inspection covers the minimum bore, end connection, ring groove, critical machining features and face-to-face length. Depending on the manufacturing route and PSL, the NDE scope can include ultrasonic, magnetic-particle, liquid-penetrant or radiographic testing.
After assembly, the valve undergoes the required body and seat pressure tests. Functional testing checks actuator travel, hydraulic pressure, valve position and full opening and closing.
| Inspection or Test | Typical Verification |
| Material Verification | Chemical composition, mechanical properties and traceability |
| Heat-Treatment and Hardness Review | Heat-treatment records and hardness compliance |
| Dimensional Inspection | Bore, connection, ring groove and face-to-face length |
| Visual Inspection | Workmanship, surface condition and marking |
| Nondestructive Examination | UT, MT, PT or RT according to the approved scope |
| Hydrostatic Body Test | Body and bonnet pressure-boundary integrity |
| High-Pressure Seat Test | Gate-to-seat sealing performance |
| Low-Pressure Seat Test | Low-pressure sealing where required |
| Functional Test | Full opening, closing and operating-cycle verification |
| Hydraulic Actuator Test | Control pressure, travel and position response |
| Final Inspection | Coating, preservation, nameplate and packing |
Third-party inspection by SGS, Bureau Veritas, DNV, ABS, TÜV or another approved agency can be arranged.
The final documentation package can include the general arrangement drawing, approved technical data sheet, bill of materials and material certificates. Heat-treatment records, hardness reports, NDT reports and body and seat pressure-test records can also be supplied according to the agreed scope.
Where required, the package may also contain hydraulic actuator test records, dimensional inspection results, coating and preservation reports, a certificate of conformity and the installation, operation and maintenance manual.
API Monogram and NACE documentation apply only when the purchase order confirms the relevant requirement and supply scope.
Installation, Operation and Maintenance
Before installation, compare the valve nameplate, nominal size and working pressure with the approved drawing. Confirm the material class, temperature rating, actuator type, fail-safe direction and hydraulic connection.
Keep the valve bore, flange faces and ring grooves clean and free from damage. Use only the designated lifting points. Do not lift the valve by the stem, hydraulic tubing or position indicator.
Install the correct API ring gasket and follow the approved bolt-tightening sequence. Support the valve and connected equipment to prevent excessive external loads on the body.
After installation, cycle the valve under controlled hydraulic pressure. Inspect the pressure-containing joints, hydraulic fittings and position indicator.
Keep the valve fully open or fully closed during normal operation. Partial opening increases fluid velocity around the gate edge and seats. Sand, scale and other solids can accelerate erosion.
Do not exceed the rated working pressure or actuator control-pressure limit. Monitor opening and closing time, confirm valve position and investigate leakage, slow movement or unusual noise.
Routine maintenance should cover the hydraulic tubing, hoses and fittings as well as actuator travel, stem leakage, position feedback and lubrication points.
Before disassembly, isolate all pressure, drain trapped fluid, depressurize the valve cavity and disconnect hydraulic energy.
Spare Parts and Replacement Hydraulic Gate Valves
Common spare parts include the flat gate, seat rings, stem, stem packing, bonnet seal and body-to-bonnet seal.
Actuator spares may include piston seals, wear rings, hydraulic fittings and complete seal kits. Position indicators, switches, sensors, lubricant fittings and sealant fittings are also available.
When ordering spare parts, provide the serial number, valve model, nominal size, minimum bore, working pressure, material class and original data sheet.
A matching nominal size and pressure rating do not guarantee direct valve replacement. Two API 6A gate valves can use different bores, face-to-face lengths, ring grooves, stem arrangements or actuator interfaces.
| Required Information | Reason for Review |
| Existing Nameplate Photograph | Identifies the model, size and pressure rating |
| OEM Model or Part Number | Supports cross-reference review |
| Nominal Size and Minimum Bore | Confirms the internal flow path |
| Working Pressure | Confirms pressure capability |
| End Connection | Confirms the mating interface |
| Face-to-Face Dimension | Confirms installation fit |
| Ring Groove or Hub Details | Confirms the pressure-sealing connection |
| Stem Arrangement | Confirms valve construction |
| Actuator Type | Confirms operating and fail-safe function |
| Hydraulic Control Pressure | Supports actuator sizing |
| Process Fluid and Temperature | Supports material and seal selection |
| PSL and PR | Confirms manufacturing and validation requirements |
| Documentation Scope | Confirms the final certificate package |
Clear photographs, original drawings and technical data sheets improve the review. Compatibility is confirmed only after completing the dimensional, pressure and operating checks.
How to Select an API 6A Hydraulic Flat Gate Valve
The correct valve depends on more than nominal size and working pressure.
First, identify the installation position. A master valve, wing valve, swab valve, fail-safe valve for a wellhead safety system and replacement gate valve may require different bores, actuators and dimensions.
Next, confirm the process fluid and operating environment. Oil, gas, water injection, gas injection and well-testing duties can require different materials and trim configurations.
The maximum working pressure, differential pressure and temperature range determine the body, seat system, packing and actuator force.
For sour or corrosive service, provide the H2S, CO2, chloride and produced-water data. For sand-producing wells, state the expected solids content and operating conditions so that the gate and seat hardfacing can be reviewed.
The final selection also covers the API 6A material class, PSL, PR, stem design and end connection. Hydraulic selection requires the supply pressure, operating time, manual override and fail-safe position.
This process matches the valve body, gate, seats, stem, actuator and end connections as one complete assembly.
Information Required for Quotation
| RFQ Item | Information to Provide |
| Application | Wellhead, Christmas tree, surface test tree, safety system or replacement |
| Valve Position | Master, wing, swab, flowline or package position |
| Nominal Size | Required API nominal size |
| Minimum Bore | Required through bore or drift diameter |
| Working Pressure | 2K, 3K, 5K, 10K, 15K or selected 20K |
| End Connection | Flanged, studded, hub or special connection |
| Material Class | Required API 6A material class |
| Temperature | Minimum and maximum operating temperatures |
| PSL | PSL 1, 2, 3, 3G or 4 |
| PR | PR1 or PR2 |
| Process Fluid | Oil, gas, injection fluid or mixed fluid |
| Sour-Service Data | H2S, CO2, chlorides and produced water |
| Solids or Sand | Expected sand content or erosion concern |
| Stem Type | Rising or non-rising |
| Actuator | Double-acting, fail-safe-close or fail-safe-open |
| Hydraulic Pressure | Minimum, normal and maximum supply pressure |
| Operating Time | Required opening and closing time |
| Manual Override | Required or not required |
| Position Feedback | Local indicator, limit switch, sensor or remote signal |
| Inspection | Client or third-party witness requirements |
| Documentation | Required drawings, certificates and reports |
| Commercial Data | Quantity and delivery destination |
Existing drawings, nameplate photographs and technical data sheets help the technical team prepare a faster and more accurate quotation.
Why Choose SGPE as Your API 6A Gate Valve Supplier?
SGPE supports new wellhead projects, Christmas tree packages, wellhead safety systems and replacement API 6A gate valve requirements.
The technical team reviews the body, gate, seats, stem and hydraulic actuator as one complete assembly. This approach aligns the minimum bore, pressure rating, end connection, actuator force and operating function.
Available capabilities include forged and cast body options, full-bore slab gates, hydraulic actuator sizing, sour-service material selection and replacement compatibility review.
Project-specific drawings, data sheets, material records, NDT reports and pressure-test documents can form part of the supply. Third-party inspection, spare parts, maintenance kits and installation support are also available.
Each quotation identifies the proposed valve design, pressure rating, material class, actuator type, inspection scope, documentation and applicable standard.
Frequently Asked Questions About API 6A Hydraulic Flat Gate Valves
1. What is an API 6A Hydraulic Flat Gate Valve?
An API 6A Hydraulic Flat Gate Valve is a high-pressure isolation valve for wellheads, Christmas trees, production trees and surface pressure-control equipment. A hydraulic actuator moves a flat or slab gate between two seats. The gate opening aligns with the valve bore when fully open, while the solid gate section blocks the bore in the closed position.
2. Is a flat gate valve the same as a slab gate valve?
Flat gate valve and slab gate valve usually describe the same parallel-gate construction. An expanding gate valve uses a gate and segment that expand against the seats near the end of the stroke. The internal components and sealing mechanism are different.
3. What sizes and working pressures are available?
The general nominal size range is 1 13/16 in. to 7 1/16 in. Standard working pressures include 2,000, 3,000, 5,000, 10,000 and 15,000 psi. Not every size is available at every pressure rating. Selected 20,000 psi requirements need separate engineering and qualification review.
4. Is the hydraulic gate valve full bore?
Most configurations use a full-bore, through-conduit slab gate design. The exact minimum bore depends on the selected model. Buyers should specify the required drift diameter when wireline, slickline or coiled tubing access is important.
5. Can the valve isolate pressure from both directions?
Selected seat designs provide bidirectional pressure isolation. The seat construction also controls the preferred installation direction, body-cavity behavior and pressure-relief function. These details are confirmed in the approved valve drawing.
6. What is the difference between double-acting and fail-safe actuators?
A double-acting actuator uses hydraulic pressure to open and close the valve. A fail-safe actuator uses hydraulic pressure in one direction and stored spring force in the other. Depending on the project, it can provide fail-safe-close or fail-safe-open operation.
7. Can the valve include a manual override and position feedback?
Yes. Available options can include a handwheel, screw override, portable hydraulic hand pump, mechanical position indicator, limit switch, proximity sensor or remote position signal. The final arrangement depends on actuator size, installation space and control-system requirements.
8. Is the hydraulic wellhead gate valve suitable for sour service?
Sour-service configurations are available according to the applicable NACE MR0175/ISO 15156 requirements. Material selection depends on H2S partial pressure, CO2, chlorides, produced water, pressure, temperature and hardness restrictions.
9. Can an API 6A hydraulic flat gate valve regulate flow?
No. The valve should operate fully open or fully closed. Partial opening increases fluid velocity around the gate and seats, which can cause erosion. A choke valve or another suitable flow-control device should regulate pressure and flow rate.
10. Can SGPE replace an existing OEM hydraulic gate valve?
Yes. Replacement review covers the existing model, nominal size, minimum bore, pressure rating, connection, face-to-face length, ring groove, stem arrangement and actuator. A matching size and pressure rating alone do not guarantee direct interchangeability.
11. What inspection and certification documents are available?
Available documents can include drawings, data sheets, material certificates, heat-treatment records, hardness reports, NDT reports, dimensional inspection and pressure-test reports. Hydraulic actuator records, coating documents, certificates of conformity and installation manuals can also form part of the final document package.
12. What information is required for a quotation?
Provide the valve position, nominal size, minimum bore, working pressure, end connection, material class, temperature rating, PSL, PR and process fluid. For hydraulic actuation, also provide the control pressure, required opening and closing time, fail-safe position, manual override and position-feedback requirements.
Request an API 6A Hydraulic Flat Gate Valve Quotation
Available options include forged or cast bodies, full-bore slab gates, metal-to-metal seats, rising or non-rising stems, double-acting actuators and spring-return fail-safe actuators.
Manual overrides, position-feedback devices, sour-service trims, hardfacing and corrosion-resistant overlays are also available.
Send the valve size, minimum bore, working pressure, end connection, material class, temperature requirement, PSL, PR, actuator function and hydraulic control pressure.
E-Mail:
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