VIV International Co., Ltd.

NEP

New Excellence Product(NEP) Certified by Korea Government

Product Name

3D Multi-stage Trim Control Valve with Air-Operated Actuator

Certified Scope

Less than 20″, Less than 2,500 lb

Characteristics

3D Multi-stage Trim control valve with air-operated actuator suitable to high pressure condition was developed using so unique technology in the world that Korea government certificated it as a ‘NEP’(New Excellent Product).

• 3D Multi-stage Trim with three-dimensional and tortuous multi-flow paths structure using the latest patented technology
• flow velocity limiting and adjusting function of trim part (less than 23 m/sec.)
• precise linear control without flow dead band
• reduced noise level with consistent cross section over flow paths (less than 80 db)
• improved trim volume ratio for preventing valve from being damaged (less than 90%)
• reduced valve damage through the separation of flow regulating and sealing function (maintenance interval: 3 years, competitor’s products : 1~2 years)

Application

Power plant Reheat and superheat attemperator spray Main and booster feed pump recirculation Condensate booster pump recirculation Turbine seal pressure control Steam generator blowdown Pressurizer PORV CVCS letdown, etc.

Petrochemical plant Production chokes Separator-level control Gas lift/injection Injection pump recycle Hot gas bypass Feedwater pump recirculation Steam header pressure control, ect.

Applied Patented Technology

Design Technology

Trim Design

    Parameters(Factors) for Trim Design

• Loss coefficient for valve shape
• Loss coefficient due to trim
• Reynolds number
• Temperature, pressure and density of fluids
• Flow characteristics curve versus valve travel
• Fluid velocity

    Design Considerations of Trim for High Differential Pressure Service(High Performance)

• Shape and size of valve
• Size of flow path and number of Stage
• Shape of flow path(resistance coefficient)
• Thickness of cylinder or disk
• Flow coefficient(Cv valve)

    ※Type of fluid shall be considered for the determination of flow coefficient valve(apply ISA 75.01).

    Limiting Valve for the Fluid Velocity(Energy)

Condition Applied	Based on Kinetic Energy		Equivalent Velocity of Water
	psi	kPa	ft/s	m/s
Single Phase Fluid	70	480	100	30
Cavitation and Two Phase Fluid	40	275	75	23
Vibration-sensitive System	11	75	40	12

Considerations for the Design(Selection) of Actuator

• Force due to the Fluid Pressure
• Weight of Plug
• Friction Force of Packing
-Packing Material
-Diameter of Stem
• Spring Force

• Frictional Force of Balance Seal
-Balance Seal Material
-Diameter of Trim
• Shutoff Force
-Seat Leakage Class
-Diameter of Seat

Analysis Technology

CFD Analysis

• Analyze fluid velocity, pressure and flow pattern at valve body, seat ring and trim using ANASYS CFX or FLUENT.

Structural Analysis

• Analyze the stress distribution due to operating load combination using ANSYS, NASTRAN and LS-DYNA, review the interference of components by calculating the displacement due to stress and validate the structural integrity and the design suitability based on the requirements of ASME and KEPIC.

Seismic Analysis

• Perform the analysis to determine whether the natural frequency exceeds 33 Hz for kinds of materials of each component and for structural shape of control valve and validate the structural integrity against seismic load(Harmonic Analysis).

Testing & Qualification

Performance Qualification

• operability Test

Equipment Qualification (ASME QME-1, IEEE 323, 344 and 382)

Application

Seat Leakage Classification of Control Valve(ANSI B16.104)

Fluid Dynamic Change of Valve

Flow Characteristics Curve and Trim Characteristics of Control Valve

Selection of optimum trim considering flow change due to pressure drop across valve and other piping component in control system.

● Linear Flow Characteristic Flow rate is directly proportional to the amount of Valve Plug Travel At 50% of rated travel, flow rate is 50% of maximum flow. At 80% of rated travel, flow rate is 80% of maximum flow. Applicable Valve Liquid Level Control Flow Control within Specific Range Valve Used D/A Level Control Valve

● Equal Percentage Characteristic For equal increments(%) of valve plug travel, equal percentage of the flow changes. At 50% of rated travel, flow rate is 18% of maximum flow. At 80% of rated travel, flow rate is 50% of maximum flow. Application Valve Pressure Control In case of high Pressure Drop Valve Used BLCV

● Modified Parabolic Between Liner and Equal Percentage Precise throttled action at low flow and similar flow to Linear characteristic at high flow

● Quick Open Characteristic Valve that needs quick opening At 50% of rated travel, flow rate is 80% of maximum flow. At 80% of rated travel, flow rate is 95% of maximum flow. Application Relief Valve

Retrofit & Up-Grade

Retrofit & Up-Grade(Grade) State of the art maintenance technique for improving the thermal efficiency due to leakage stoppage and the extension of life time and maintenance interval as well as the better performance(control ability, anti-erosion and corrosion and anti-leakage) than existing control valves through the redesign, repair and replacement of critical part(trim part) using hydro-dynamic technology

Possible Targets for Retrofit & Up-Grade Most of the valves designed prior to the year of 1990. Valves whose service conditions such as flow and differential pressure are changed. Valves having short replacement interval of their components(which require a lot of spare parts). Valves having lots of erosion, wear and damage of components. When requested by users. Valves being expected of better performance with new design technology.

Necessity of Retrofit & Up-Grade To Safety the customer’s desire for new high quality products. To be prepared for the obsolescence of existing products and to meet the requirement for the increased level of reliability Retrofit & Up-Grade technology with the optimum design of major component(trim part) is available.

Applicability of HARMONY Trim to Retrofit & Up-Grade Excellent Retrofitability by optimum design(reduction of cage volume ratio). Structural mechanics design to protect from inflow of foreign materials. Leakage blockage by plug & seat design with double-blocking structure. Reduction of maintenance cost by performing retrofit without any modification of valve body and actuator. Clearance of the problem such as leakage, noise and vibration, ect. And increase of durability. Improvement of control performance and reliability.

Application of Trim Characteristics Considering System

Target for Performance Improvement

    Power Plant Problem Valves

• MFWP & COP Recirculation valve
• HTR Drain Dump/Control valve
• Boiler(S/G) Pressure Control valve
• Main Steam Dump valve

    Feedwater Control Valve Solutions

• Characterized Harmony Trim to eliminate cavitation and vibration
• Cylinder operator for high force loads for optimum control
• Flow to close design uses disk stack to protect critical guide and seating surfaces

Other Application

Noise reduction device in discharge side of the Pressure relief valve
Noise reduction by orifice or alternative design
Back-pressure device of the high pressure drop(Recirculation) valve
Integration of the overpressure protective and control function

Plasma Coating

Republic Korea  Utility Model No. 20-415452 Title  Valve Device Forming Carbon Ion Implantation Layer on Surface

    Characteristics

• Carbon ion implantation layer of uniform thickness is formed on the surface of part using the Plasma Source Ion Implantation(PSII) to strengthen the hardness, abrasion resistance and mechanical characteristics.
• Fluid leakage is prevented by protecting major valve components(trim part, plug, seat ring and cage) from the damage(erosion, corrosion, wear, galling and scratch) due to interaction of components and fluid kinetic energy occurred by differential pressure and high fluid velocity.

    Pictures showing the Coating Application

    Result of Coating Application