2-Inch

Export-Ready for Offshore, Desalination & Marine Markets

origin Mumbai (JNPT) | CIF worldwide ports | 3.1/3.2 EN 10204 certs | Pilot-controlled precision regulation

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NAB Pressure Reducing Valve — 2" Class 150 — 4.5 BARG Set

Supreme Valves India manufactures NAB (Nickel Aluminium Bronze C95800) Pressure Reducing Valves for seawater and marine service, featuring pilot-controlled operation for precise downstream pressure regulation. The 2" Class 150 flanged valve is factory-set at 4.5 BARG minimum and is ideal for maintaining stable service pressure in desalination plant piping networks, offshore platform water distribution, and marine vessel utility systems. The pilot-controlled design ensures stable outlet pressure regulation across a wide range of flow rates without chatter or instability. NAB construction ensures long-term reliability in chloride-rich seawater environments.

How the Pressure Reducing Valve Works

1

High-Pressure Inlet

Seawater at high inlet pressure (up to Class 150 rating) enters the valve body. The pilot valve senses downstream pressure via the control line.

2

Pilot Modulation

The pilot valve compares sensed downstream pressure against the spring setpoint (4.5 BARG). If outlet pressure falls below setpoint, the pilot bleeds pressure from the top of the main diaphragm.

3

Stable Outlet Pressure

As the diaphragm moves, the valve plug repositions to throttle the flow, maintaining the set outlet pressure regardless of flow rate variations. Excess pressure is safely relieved or bypassed.

Materials of Construction (MOC)

Component Material Specification
Body & Bonnet Nickel Aluminum Bronze (ASTM B148 C95800)
Stem / Spindle Monel 400 / K500
Seat / Trim NAB / PTFE / Viton

Technical Specifications

Parameter Specification / Standard
Manufacturing / Design Standard API 609 / API 600 / ASME B16.34
Testing Standard API 598 / EN 12266-1
Pressure Rating Class 150 / Class 300 / PN16

Material of Construction

S.N.Parts NameMaterialQty
1BodyInvestment Casting (ASTM A 351 Gr. CF8/CF8M)1
2DiscInvestment Casting (ASTM A 351 Gr. CF8/CF8M)1
3SpringS.S.304 / S.S.3161
4Spring WasherS.S.304 / S.S.3161

Testing Details & Standards

  • Class: PN-40
  • Hydro Test Pressure Body: 60 Kg/cm²
  • Seat: 44 Kg/cm²
  • Duration: 1 Minute

Dimension Tables

SizeInchM.M.ØDØD1ØD2L
1/2"1/2"1515386016
3/4"3/4"2020477020
1"1"2524558022
1.1/2"1.1/2"40397510032
2"2"50509311540
2.1/2"2.1/2"656510914246
3"3"807612715450
4"4"1009814818460
5"5"12512517722569.5
6"6"15015020223074
8"8"200201266333140

Frequently Asked Questions

What is a pressure reducing valve and how does it work?

A pressure reducing valve (PRV) is a self-operated or pilot-controlled valve that reduces a high inlet pressure to a lower, constant outlet pressure regardless of flow variations. It operates on the principle of force balance: when downstream pressure rises above the spring setpoint, the valve closes; when it drops, the valve opens. Pilot-controlled PRVs (like our NAB PRV) use a separate pilot valve that senses downstream pressure and modulates the main valve's diaphragm/spring assembly for more precise control across a wide flow range.

What does '4.5 BARG set pressure' mean?

BARG stands for 'bar gauge' — pressure measured relative to atmospheric pressure (zero = atmospheric). 4.5 BARG means the valve is factory-set to maintain a downstream pressure of 4.5 bar above atmospheric (approximately 65 PSI gauge). The 'minimum 4.5 BARG' specification from the inquiry indicates this is the minimum set pressure required — the valve can be adjusted to higher set pressures up to the inlet pressure rating. For seawater distribution networks in marine applications, 4.5 BARG is a common working pressure for service lines.

Why use Nickel Aluminium Bronze for a pressure reducing valve?

Nickel Aluminium Bronze (NAB, C95800) is used for pressure reducing valves in seawater and marine applications because of its exceptional corrosion resistance. NAB resists crevice corrosion, impingement attack, and biofouling in seawater at temperatures up to 80°C. For a PRV in a desalination plant or offshore platform, this means the valve body and internals will not corrode or scale, maintaining accurate pressure control over the valve's service life without frequent maintenance or replacement.

What is the difference between a direct-acting and pilot-controlled PRV?

Direct-acting PRVs use a spring-loaded diaphragm to modulate the valve directly based on downstream pressure changes. They are simpler and lower cost but are limited to smaller sizes and lower flow capacities. Pilot-controlled (or pilot-operated) PRVs use a separate pilot valve to modulate pressure on the diaphragm of the main valve. This provides: (1) Higher flow capacity at lower pressure drop, (2) More precise downstream pressure control, (3) Better stability at varying flow rates, (4) Ability to handle large pressure differentials in a single valve. Pilot-controlled PRVs are preferred for most industrial and marine applications.

Can the set pressure of the NAB PRV be adjusted after installation?

Yes. The NAB pressure reducing valve is adjustable within its designed range. The adjustment is made via the pilot spring adjustment screw on the pilot valve, which changes the set point from the minimum (4.5 BARG) up to the inlet pressure rating. For seawater applications where the set pressure is critical for downstream equipment protection, the adjustment range and accuracy should be confirmed with our engineering team before ordering. Typically, the factory-set pressure is specified at ordering but can be field-adjusted within ±10–15% of the set point.