Grayloc® Closure Systems

Providing easy, quick, and safe access.

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Our Closure Systems provide simpler and faster access to pressure vessels and other pressurized equipment by combining our Grayloc Clamp Connector with clamp supports and a hinged door. Suitable for use in extreme temperatures and pressures, the customizable systems can be oriented vertically or horizontally to meet your operational needs.

Large Diameter Applications V3

Well-suited for large diameter applications

Frequent Access 1

Enable safe, rapid, and frequent access

Eliminate Fugitive Emissions Icon 2 Edited

Eliminate fugitive emissions

Grayloc Closure Systems Callouts

Technical Specifications

Nominal pipe size6 to 36 in, larger sizes available upon request
Design pressure ratingFrom full vacuum up to 60,000 psig
Design temperature range-423 to 1700°F / -253 to 927°C

Hub Nickel alloys, carbon, low-alloy, stainless and duplex stainless steels
Seal ring Nickel alloys, low-alloy, stainless and duplex stainless steels
Bolting Nickel alloys, carbon, low-alloy, stainless and duplex stainless steels
TrunnionNickel alloys, carbon, low-alloy, stainless and duplex stainless steels
Support plateNickel alloys, carbon, low-alloy, stainless and duplex stainless steels
Drive screwNickel alloys, low-alloy, stainless and duplex stainless steels
Hinge pinNickel alloys, carbon, low-alloy, stainless and duplex stainless steels

ASME B31.1, Power Piping
ASME B31.3, Process Piping
ASME B31.4, Pipeline Transportation Systems for Liquids and Slurries
ASME B31.8, Gas Transmission and Distribution Piping
ASME B31.12, Hydrogen Piping & Pipelines
ASME Section I
ASME Section VIII Div. 1
ASME Section VIII Div. 2
ASME Section VIII Div. 3
API 6A: Specification for Wellhead and Christmas Tree Equipment

Product Documents


MSV Normand Superior | Letter

Uncrewed Surface Vessel Services | Letter

Optional Features Our self-contained, ready-to-install closure assemblies can be customized to meet your project and access requirements.

  • Seal ring retention system

  • Pressure sensor

  • Temperature sensor

  • Safety interlock systems

  • Zero pressure verification (vent valve)

  • Automated opening and closing

  • Sight glass

  • Bolt shrouds

  • Adjustable hinges

  • Hydraulic nuts for bolt tensioning

  • Single drive screw (remote clamp layout)

  • ASME code stamped

Typical Applications

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Product Variations

Vertical Closure - Closed
Vertical Closure - Open
Remote Closure - Closed
Remote Closure - Open
Horizontal Closure - Closed
Horizontal Closure - Open

Field Inspection and Maintenance Services

Grayloc offers on-site inspection and maintenance services to ensure the integrity of our connectors and to facilitate the return of worn or damaged hubs and equipment to within factory specifications.

Contact us for more information

Contact Us

Contact Us | Grayloc® Closure Systems

Company page Since our founding in the early 1960s, Oceaneering has expanded and grown globally to service several industries such as the offshore energy industry, defense, entertainment, material handling, aerospace, science, and renewable energy industries. In 1964, Mike Hughes and Johnny Johnson formed a Gulf of Mexico diving company called World Wide Divers. The company grew in response to increasing demand for their services and in 1969 merged with two other diving companies to form Oceaneering International, Inc. To solve the toughest challenges, we do things differently, creatively, and smarter. As your trusted partner, our unmatched experience and truly innovative portfolio of technologies and solutions give us the flexibility to adapt and evolve, regardless of market conditions. Our mission is to solve the unsolvable. We thrive by creating industry-changing technically creative solutions for the most complex operational challenges under water, on land, and in space. Our five core values establish a common culture and demonstrate what is most important for us as a company. Since the beginning, the company has transformed from a small regional diving company into a global provider of engineered products and services. Today, we develop products and services for use throughout the lifecycle of an offshore oilfield, from drilling to decommissioning. We operate the world's premier fleet of work class ROVs. Additionally, we are a leader in offshore oilfield maintenance services, umbilicals, subsea hardware, and tooling. We also serve the aerospace, defense, and theme park industries. Underpinning everything we do, safety is not only the foundation of our core values, but it is vital to our unmatched performance record and company culture. The industries we serve are as diverse as they are complex. Whether we are engineering deepwater umbilicals or developing robotics for aerospace applications, the safety and health of our employees, vendors, and customers is an integral part of our day-to-day business. If we are working, then our responsibility is to be working safely. Since our inception in 1964, we have placed a high value on employee safety—from diving services and subsea inspection to vessel-based installation operations. We have and will continue to evolve not only our health, safety, and environmental (HSE) processes, but those of the industries in which we work. Although we have been fatality-free since 1999, our HSE journey goes beyond statistics. As our portfolio of services has grown, we have continued to prioritize and advance our approach to HSE.