Optimized Valve Sizing for Modular Linear Valves

Sectional drawings: valves by SAMSON
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With their flexible, modular design, our SAMSON control valves can be tailored to the specific control task, which allows them to meet even the most challenging requirements under severe operating conditions.

SAMSON can supply modular control valves with globe, angle and three-way bodies in all common pressure ratings and materials at short notice. The valves are designed in accordance with the ANSI, DIN or JIS standards and available with different flange types and welding ends.

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Valve body

We have all common valve body styles and end connections in our product range, which can be combined in almost any way thanks to their modular design. No matter whether you are looking for a globe valve with screwed ends, a three-way valve with flanges or an angle valve with welding ends, SAMSON can supply you with the right valve body in the highest quality to meet your requirements.

The valves are available in a wide range of materials. To deliver the highest quality, the valve bodies are subjected to extensive inspection and testing before the valves are assembled. We perform inspections and tests depending on the valve material. The results are documented in a test report or inspection certificate depending on customer specifications.

Globe valve

  • Easy installation in straight pipelines
  • Three-flange body for pressure ratings up to PN 400/Class 2500 and valve sizes up to DN 500/NPS 20

Three-way valve

  • Use as mixing valve: two partial flows are combined to create one flow
  • Use as diverting valve: one flow is split and leaves the valve as two separate flows

Angle valve

  • Optimal condensate discharge
  • Almost entirely self draining
  • Optional anti-wear sleeve in the valve outlet of flow-to-close (FTC) valves


  • Easy to mount and disassemble
  • Leak tight
  • DIN, ANSI, JIS and GOST versions with standardized face-to-face dimensions (others available on request)

Welding ends

  • No maintenance
  • Leak tight even with critical media
  • Optionally with welding-neck ends


Body with screwed ends

  • NPT female thread for valve sizes up to NPS 2
  • Material saving
  • Flexible in use


Cast body

  • Various casting materials available: cast iron, spheroidal graphite iron, cast steel, stainless steel, duplex steel, nickel alloys
  • Resistant to corrosion and wear

Forged steel body

  • Valves in sizes up to DN 80 made of 1.0460 or 1.4571 as standard, other materials possible: stainless steel, duplex steel, nickel alloys
  • Homogenous molecular and grain structures
  • Reduced cost of testing without any impairment in quality

Body made of bar stock or block material

  • High degree of flexibility for chemical applications (e.g. body free of dead spaces for the pharmaceutical and food industries)
  • Special constructions available


The targeted valve leakage depends on the plant requirements and the process medium used. Reducing leakage is not only relevant to hazardous substances. It applies to all media. While seat leakage is decisive to the proper functioning of the process, the control of fugitive emissions at the packing, bellows and flange is stipulated in various standards and regulations to reduce emissions and protect the environment.

The valves are tested according to the standardized procedures and their measured seat leakage is specified in leakage classes according to IEC 60534-4 or ANSI/FCI 70-2. Depending on the application, the seat and plug have either a metal or soft seal.

Metal seal

  • Suitable for leakage classes IV and V
  • Used for throttling service

Soft seal

  • PTFE seal for low seat leakage up to leakage class VI

The packings meet the fugitive emission requirements according to VDI 2440 and, as a result, fulfill the requirements of TA Luft (German technical instructions on air quality control). SAMSON's ISO packings are tested based on EN ISO 15848 and comply with the external leakage rates depending on the temperature, load and pressure even in continuous operation. The ANSI/FCI 91-1 standard and EPA (Environmental Protection Agency) specifications apply to ANSI valve versions.


  • Long service life
  • Low level of friction and leakage, particularly with polished plug stem
  • Improved sealing performance by using the combination of a special V-ring packing design and the medium pressure
  • Standard: self-adjusting, spring-loaded V-ring packing made of PTFE-carbon
  • Optional: adjustable, cavity-free packing in various materials (PTFE-silk, pure PTFE)

Cryogenic testing

Cryogenic valves must fulfill a wide range of special requirements also including leakage.

  • Cryogenic testing based on BS 6364
  • Seat leakage testing based on IEC 60534-4 and ANSI/FCI 70-2 performed on special test benches

Valve trims

Parabolic or V-port plugs are used as standard. Other modular designed valve trims are available to meet special requirements..

Parabolic plugs have a rugged design and are insensitive to dirt particles.

  • Cost effective
  • Insensitive to small dust particles
  • Prevent cavitation at low pressure drops
  • Suitable for on/off service with one-sided plug stem guiding

V-port plugs have three V-shaped ports. Their size varies depending on the valve size. The process medium in the valve flows through the V-shaped ports as soon as the plug is lifted out of the seat (i.e. the valve opens).

  • Asymmetrical distribution of the orifice cross-section prevents plug vibration in critical operating conditions
  • Minimized vibration through double-guided plug stem (guide bushing and seat guide)
  • Insensitive to small dust particles

Flow dividers shorten the free jet exiting the vena contracta and accelerate the energy transfer in the mixing zone. As a result, noise emissions are reduced when handling gases and vapors.

  • Used with gases and vapors
  • Noise reduction for increased operational reliability
  • Cost effective due to modular design
  • Reinforced versions for high-pressure service
  • No noticeable deviation from the characteristic (up to 80 % travel)

See data sheet for further details
T 8081 EN: Flow Dividers for Control Valves

A single-stage letdown at differential pressures up to 250 bar can be achieved using the Zero Travel 1 (ZT-1) trim.

  • Flow-to-close (FTC) direction of flow
  • Suitable for liquids, two-phase flows or gases
  • Use in high-pressure letdown and critical steam applications
  • Longer service life by separating the seating surface and throttling area
  • Improved stability provided by an additional guide in the seat area

See data sheet for further details
T 8087 EN: Control Valves with Zero Travel 1 Trim

Perforated plugs are optimized to reduce noise levels. The process medium flows through the perforated plug and the jet stream is split into numerous smaller jets to ensure low-noise energy transfer to the surrounding medium.

  • Flow-to-open (FTO) and flow-to-close (FTC) directions of flow possible
  • Reduced vibration
  • Suitable for critical medium states and steam service, particularly for operation in the wet steam region or with flashing conditions

See data sheet for further details
T 8086 EN: Valves with perforated plug

AC trims (AC-1, -2, -3 and -5) are optimized for the low-noise and low-wear pressure reduction of liquids. The AC trims ensure that the pressure is let down gradually across several throttling stages to prevent cavitation.

  • Use at high pressure drops
  • Additional plug guiding integrated into the seat and top guide bushing to ensure low-vibration operation of the valve
  • Substantially longer service life

See data sheet for further details
T 8082 EN: Pneumatic Control Valves with AC-1 or AC-2 Trim
T 8083 EN: Pneumatic Control Valves with AC-3 or AC-5 Trim

    Stellite®-faced or vacuum-hardened trims

    The trims are Stellite®-faced or hardened in vacuum ovens to make them suitable for use with erosive and abrasive media.

    • Highly resistive to erosion
    • Used when cavitation, flashing and two-phase flows occur


    The bonnet seals off the valve at the top and accommodates the packing and plug stem guiding. The valve bonnet is a pressure-bearing component that is exposed to the process medium. Therefore, its material is subject to the same design requirements as the valve body.

    The bonnet, which seals off the valve at the top, is used to mount the actuator or yoke. The standardized NAMUR rib located on the yoke allows easy, standardized attachment of a positioner or other valve accessories.

    • Pressure-bearing part made of the same material used for the valve body
    • Allows the actuator to be removed without having to dismantle the valve

    Series 240 (up to DN 150):

    • One single component for bonnet and yoke for a compact, rugged, lightweight construction

    The bellows seal is installed in addition to the packing between the actuator and valve to seal off the plug stem.

    • Strict fugitive emission requirements, e.g. as specified by TA Luft/ISO 15848
    • Optional test connection and leakage indicator to monitor the sealing performance
    • Long service life guaranteed by shorter stroking with multiple convolutions per millimeter
    • Can be retrofitted and/or exchanged

    The bellows seal also acts similar to an insulating section as it keeps the packing and actuator at a sufficient distance from the process medium to protect them against excessive temperatures.

    The insulating section serves to keep the packing and actuator at a distance from the process medium.

    • Extends the temperature range of the standard packing to between –196 and +450 °C/–320 and 842 °F

    Cryogenic valves:

    • Optional circulation inhibitor prevents the process medium from circulating inside the insulating section and protects the bonnet against extremely low temperatures (e.g. icing up).

    Pneumatic actuators

    SAMSON valves are preferably fitted with Type 3271 and Type 3277 Pneumatic Actuators, which have been proven in use over decades. Standardized interfaces (IEC 60534-6-1 and VDI/VDE 3847) as well as the direct attachment developed by SAMSON for Type 3277 Actuators allows actuators to be fitted with accessories, such as positioners, limit switches and solenoid valves. Through the modular design, the actuator and valve can be easily upgraded to achieve automated valves with short transit times suitable for use in safety-instrumented systems.


    In the age of the Internet of Things, it is a matter of course that control valves are integrated into process control systems. Data on the control valve itself and diagnostic data are collected, saved, analyzed and transmitted to the process control system by digital field devices. Similarly, data can be forwarded from the process control system to the field devices. The field devices used in control valve engineering are usually positioners – in some cases also limit switches –, which are mounted on the control valve.

    Positioners compare the set point issued by automation equipment (controller, control station, process control system) to the valve's position and supply the actuator with a corresponding output signal pressure (pst). SAMSON's digital positioners are also able to collect, analyze and transmit operating data.

    • Mounting facilitated by the use of standardized interfaces
    • Rugged, long-life metal housing
    • Intuitive operation
    • International explosion protection certificates
    • Integration of many optional additional components into the positioner housing
    • Automatic start-up
    • Communication using HART®, PROFIBUS® or FOUNDATION™ fieldbus protocols
    • EXPERTplus valve diagnostics

    » Read more

    SAMSON's EXPERTplus valve diagnostics can detect faults and provide predictive, status-oriented maintenance recommendations for valves with pneumatic actuators. The full scope of diagnostic functions is completely integrated into the positioner. The numerous diagnostic functions allow faults to be pinpointed in control and on/off valves at an early stage.

    • Compilation of diagnostic data
    • Automatic start of diagnostic functions and tests
    • Tests to monitor valve operation while the process is running
    • Tests to analyze the condition of the entire control valve
    • Status classification and condensed state according to NAMUR Recommendation NE 107
    • Diagnostic data, test results and analyses saved in the positioner
    • TROVIS SAFE series: on/off analysis with partial stroke test (PST)

    » Read more

    SAM DIGITAL allows diagnostic data of all tags in the plant to be documented and analyzed.

    • History of each tag/valve
    • Provides users with proactive maintenance recommendations
    • Identifies critical tags
    • Allows flexible planning of service work

    » Read more