Grayloc® Non-Slam Nozzle Check Valves

Delivering superior performance and reliability in a maintenance-free design.

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Our Non-Slam Nozzle Check Valve includes an optimized flow profile and unique dual-spring design to solve operational issues, including pressure loss and reverse flow, common with alternative check valve designs. Low friction movement, low part weight, and short disc stroke ensure stable, maintenance-free operation, even in low flow applications. Our customizable and inherently fire-safe valves can be installed horizontally, vertically, and diagonally to meet your most challenging operational needs. 

Eliminate Disc Chatter Icon

Sized to eliminate disc chatter

Prevents Return Flow Icon

Eliminates reverse flow and hammer

Eliminate Disc Chatter Icon

Optimized for low pressure loss

Spring Icon 1

Unique dual-spring design enables fast dynamic response

Nozzle Check valve callouts

Technical Specifications

Nominal pipe size1 to 72 in
End connectionsGrayloc clamp connectors and compact flanges, ASME B16.5 flanges, ASME B16.47 flanges, ASME B16.25 weld ends, NORSOK L-005 compact flanges, AS4087 flanges, and API 6A flanges

Other end connections available upon request.
Design pressure ratingSuitable for ANSI Class 150 up to 10,000 psig
Design temperature rangePer material limit (full metal construction)
Flow orientationUp, down, diagonal, and horizontal

Body (forged or cast) Nickel alloys, carbon, low-alloy, stainless and duplex stainless steels
Disc (forged or cast) Nickel alloys, carbon, low-alloy, stainless and duplex stainless steels
Body seat All API trims. Custom trims available upon request.
Disc seat All API trims. Custom trims available upon request.
Internal coating Fusion bonded epoxy or as specified by customer
External coating Per customer specifications

ASME B16.34, Valves - Flanged, Threaded, and Welding End
ASME B16.10, Face-to-Face and End-to-End Dimensions of Valves
AS4794, Non-Return Valves for Waterworks Purposes
API 6A, Specification for Wellhead and Christmas Tree Equipment
API 6D, Specification for Pipeline Valves
API 594, Check Valves: Flanged, Lug, Wafer and Butt-Welding
API 598, Valve Inspection and Testing

Product Documents


Grayloc® Non-Slam Nozzle Check Valve Catalog | Letter

Grayloc® Hub Ended Nozzle Check Valve | Letter

Grayloc® Non-Slam Nozzle Check Valve | Letter
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Typical Applications

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Contact Us | Grayloc® Non-Slam Nozzle Check Valves

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.