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290 Birch Street (Brea, CA)

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2950 Birch Street
Brea, CA 92821
T: +1.714.528.2301
Email: enertech@curtisswright.com Email: PME@curtisswright.com

NozzleCheck

The NozzleCheck is a non-slam check valve first developed in 1935. The first NozzleCheck valve installed in a nuclear power plant was in 1972; since then it has replaced over 800 conventional check valve designs.

In-Line Check Valves

Specifically designed to combat damaging transients and water hammering, the NozzleCheck valve has been improving systems in some of the most demanding nuclear plant applications.

With a number of designs, NozzleCheck offers check valves for large and small bore, dirty, high capacity, and severe service applications.

In 1992, Curtiss-Wright Nuclear started manufacturing NozzleCheck valves under its Appendix B Program. Since that time, Curtiss-Wright Nuclear has been exclusively offering ASME Section III Class 1, 2, and 3, Safety-Related and Commercial NozzleCheck valves to the nuclear industry.

Models

    DRV-Z

    The NozzleCheck DRV-Z is an axial flow, inline check valve. Similar to a conventional check valve, the DRV-Z allows forward flow under normal conditions, opens quickly with ease, firmly backseats at a low velocity and closes on a reverse flow with minimal seat leakage.

    The DRV-Z provides a maintenance free design using minimal moving parts and a very short stroke to provide a rapid non-slam closure. This makes it a perfect choice for vertical and horizontal pipe configurations and is ideal for installations near sources of turbulence such as elbows, reducers, pumps and orifices. The DRV-Z model is well suited for small bore applications protecting critical equipment from reverse flow, containment isolation of pressure boundary penetrations, excessive tank vacuum and high energy line break isolation.

    Key Features and Benefits

    Short Stroke length Extremely quick closure
    Low Mass Disc Non-slam closure, eliminating water hammer induced damage
    Spring loaded disk Allows mounting in any orientation
    Conical seating surface Self-aligning seat, provides tight shutoff
    Integral disk/stem construction Rigid structure to handle severe turbulence, eliminates flutter
    Low friction bushing surface, no hinge pins No scheduled maintenance, long service life

    Principles of Operation

    The DRV-Z small bore axial flow inline check valve is able to allow full forward flow under normal operation. As forward flow velocity reduces to a specified minimum (Vmin), the spring assisted disk firmly closes, preventing reverse flow. The DRV-Z employs a streamlined diffuser that minimizes pressure loss. A disk/stem assembly also provides a rigid structure within a low friction surface to minimize wear. Disk closure relies on differential pressure with assistance from the spring. The DRV-Z can be selected for applications with a specified Vmin or opening pressure to meet system requirements.

    General Specifications

    Size: 3/4" - 10"
    Ratings: ANSI Pressure Class 150 to 2500
    Connections: Flanged, Socket or Butt Weld
    Quality Class: Commercial, Safety-Related, ASME Code, Class 1, 2, 3

    Plant Design

    PWR, BWR, CANDU

    Typical Plant Applications

    • Auxiliary Feedwater Steam Supply System
    • RCIC Turbine Exhaust
    • Pressure Boundary/Containment Isolation
    • Safety Injection System
    • Instrument Air Systems
    • Tank/vessel vacuum protection
    • High Energy Line Breakage Isolation
    • GL 89-04 Safety Related Applications

    DRV-B

    The DRV-B is used for large bore check valve applications where high capacity is required. It has a donut shaped disc allowing flow through the inside and outside of the disc. The disc is free floating and does not rely on the alignment of any guiding surface for proper seating. Large bore axial flow check valve.

    The DRV-B typically uses 3 helical springs to control the closing speed and apply additional seat load under low differential pressure conditions. The DRV-B has a diffuser that allows a smooth transition of areas reducing pressure loss and creating a low-pressure area behind the disc to create sufficient force to fully open the valve.

    Key Features and Benefits

    Short Stroke, Spring Assist and Low Mass Disc Ability to close quickly, eliminating waterhammer
    Dynamic Testing Complete Proof of speed of response, no other axial flow check valve has had these curves tested and documented
    Two Flow Paths Around Disc Higher capacity than other axial flow check valves
    Tight Seating in High
    Differential Pressure Flow
    Vertical Installation
    Low seat leakage improved operational efficiency
    Diffuser Smooths flow transition while minimizing pressure loss

    Principles of Operation

    The DRV-B is installed to allow flow in only one direction. As pressure is reduced on the inlet side compared to the outlet, flow will reduce. When the flow is reduced to a point, depending on the spring strength, the valve will start to close. It will fully close at nearly the zero flow condition. Three or four helical springs are used, depending on valve size, to provide a closing force. Springs are sized to be strong enough to close quickly to eliminate waterhammer and weak enough to allow full open operation during normal operating modes.

    General Specifications

    Size: 12" to 72"
    Ratings: ANSI Class 150 and 1500
    Connections: RFF, RTJ, BW
    Quality Class: Commercial, Safety-Related, ASME Section III

    Plant Design

    PWR, BWR, CANDU

    Typical Plant Applications

    • Feed Pump Discharge
    • Feed Header
    • Component Cooling Water Pump Discharge
    • Service Water Pump Discharge
    • Heater Drain Pump Discharge
    • Extraction Steam
    • Cooling Water Pump Discharge
    • Condensate and Condensate Booster Pump Discharge
    • SFP Pump Discharge

    DRV-BK

    The DRV-BK is used for large bore check valve applications where a narrow face-to-face is required. It has a donut shaped disc allowing flow through the inside and outside of the disc. The disc is connected to a center shaft.

    The DRV-BK has one helical spring enclosed within the center body section to control the closing speed and apply additional seat load under low differential pressure conditions. The DRV-BK does not have a diffuser like the DRV-B and DRV-Z.

    Key Features and Benefits

    Short Stroke, Spring Assist and Low Mass Disc Ability to close quickly, eliminating waterhammer
    Dynamic Testing Completed and Documented Proof of speed of response, no other check axial flow has had these curves tested and documented
    Two Flow Paths around Disc Higher capacity than other axial flow check valves
    Tight Seating in High
    Differential Pressure Flow Up Vertical Installation
    Low seat leakage

    Principles of Operation

    The DRV-BK is installed to allow flow in only one direction. As pressure is reduced on the inlet side compared to the outlet, flow will reduce. When the flow is reduced to a point, depending on the spring strength, the valve will start to close. It will fully close at nearly the zero flow condition. The center spring provides a closing force. Springs are sized to be strong enough to close quickly to eliminate waterhammer and weak enough to allow full open operation during normal operating modes.

    General Specifications

    Size: 12" to 72"
    Ratings: ANSI Class 150 and 1500
    Connections: RFF, RTJ, BW, Lugged and Wafer
    Quality Class: Commercial, Safety-Related, ASME Section III

    Plant Design

    PWR, BWR, CANDU

    Typical Plant Applications

    • Component Cooling Water Pump Discharge
    • Service Water Pump Discharge
    • Extraction Steam
    • Cooling Water Pump Discharge
    • Condensate and Condensate Booster Pump Discharge
    • SFP Pump Discharge

    DRV-N

    In some applications the fluctuation in pressure, downstream leaks, or other phenomena can result in constant chatter of a check valve causing hinge pin wear or damage to the seating surface. The DRV-N, Normally Open NozzleCheck valve, has been designed to withstand the rigors of these types of applications.

    Principles of Operation

    This particular design has a similar body configuration to the Model DRV-Z, but rather than a normally closed design that is opened using system pressure, the disc in the DRV-N is opened using a spring. As a result, the valve is unaffected by pressure changes and the problem of constant cycling is avoided. Furthermore, the DRV-N employs the use of a stem guide rather than a diffuser. This feature provides a less congested flow path so that the backpressure can effectively close the valve when flow exceeds normal levels. When closed, the disc is self-aligning and finds the best seating position to form a tight shutoff.

    General Specifications

    Sizes: ½” – 12”
    Pressure Class: 150 to 4500lb
    Body Type: Flanged, Butt Weld, and Socket Weld

    Plant Design

    PWR, BWR, CANDU

    Typical Plant Applications

    • AFPT Steam Supply
    • Applications with Fluctuation in Pressure

    Available NozzleCheck Products

    • DRV-Z Small Bore
    • DRV-B Large Bore
    • DRV-BK Large Bore, Short Face
    • KRV-B Large Bore, Short Face
    • DRV-N Normally Open
    • XRV Specially Engineered