SAMSON Type 3321 Globe Control Valve DN 15-100 (V2001)

SAMSON Type 3321 globe valve of the V2001 series

The SAMSON Type 3321 is a single-seated globe control valve from the Series V2001, designed for mechanical engineering and process plant duty on liquids, gases and steam. The DIN version covers nominal sizes DN 15 to 100, pressure ratings PN 16 to 40 and a temperature range of –10 to +300 °C. Seven Star LLC supplies the Type 3321 in Oman and the GCC as an independent supplier based in Muscat.

The valve body is only half of the control loop. The same Type 3321 is offered with an electropneumatic actuator and positioner (suffix IP), a pneumatic actuator (PP), or an electric actuator (E1 or E3). Valve and actuator are delivered separately, so you can match each size to your supply air or electrical supply on site.

Each nominal size is offered with two flow coefficients, and the plug can be metal-seated or soft-seated. That gives a wide choice of KVS from 0.25 up to 160 within one compact design.

Decoding the Type 3321 suffixes

• 3321-IP: Type 3372 electropneumatic actuator with a Type 3725 positioner, 4 to 20 mA set point, up to 6 bar supply air, fail-close or fail-open, optional limit switch.
• 3321-PP: Type 3371 pneumatic actuator of 120 cm² (DN 15 to 50) or 350 cm² (DN 65 to 100), fail-close or fail-open.
• 3321-E1: Type 5827-N3 electric actuator for DN 15 to 50, 230 V/50 Hz or 24 V/50 Hz, with optional limit contacts, resistance transmitter or positioner.
• 3321-E3: Type 3374 electric actuator for 230 V or 24 V at 50 or 60 Hz, optionally with fail-safe action tested per DIN EN 14597, limit contacts, resistance transmitter and positioner.

An ANSI version of the Type 3321 is described in a separate SAMSON datasheet, and explosion-protected electric actuators are available on request.

Type 3321 technical specifications

How the Type 3321 globe valve controls flow

The medium flows through the valve in the direction shown by the arrow on the body, in flow-to-open direction. The position of the plug against the seat sets the cross-section available, and the plug stem is joined to the actuator stem by a stem connector. A self-adjusting packing seals the stem.

With a spring-loaded pneumatic actuator or an electric actuator with fail-safe action, the valve has two fail-safe positions. If the actuator stem extends on failure, the valve closes (fail-close). If the stem retracts, the valve opens (fail-open). Choose the direction by thinking what the process needs when air or power disappears: cooling water usually fails open, a fuel or steam supply normally fails closed.

The pressure drop the valve can close against depends on actuator area, bench range and KVS. The datasheet gives tables of allowable differential pressure per KVS and actuator, for both metal and soft seats, up to 40 bar for the smaller coefficients. Always check those tables for your KVS before locking the actuator selection.

Type 3321 sizes and flow coefficients

The datasheet also lists reduced coefficients when the ST 1 flow divider is fitted, which lowers noise at high pressure drop. Rated travel is 15 mm for most sizes and 30 mm for the largest KVS.

Choosing a Type 3321 package

• Process medium, pressure and temperature, which decide the body material and whether an insulating section is needed above +220 °C.
• Pressure rating and flange standard: PN 16, 25 or 40 and the matching DIN face.
• Required KVS and nominal size, taking account of the allowable differential pressure with your actuator.
• Seat leakage: metal seat for class IV, soft seat for class VI.
• Actuator style: IP with positioner, PP, E1 or E3, and the supply air or voltage available.
• Fail-safe action: fail-close or fail-open, and the optional limit switch or position transmitter.
• Whether the Type 3725 positioner or a different SAMSON positioner is wanted.

Installing and maintaining the Type 3321

Install the valve with the flow arrow matching the line direction. Mount the actuator with the supplied adapter or crossbeam: the datasheet shows form B with a crossbeam for DN 15 to 50 and form C without crossbeam for DN 65 to 100 on pneumatic versions. Piping should be flushed to remove weld spatter before the valve is commissioned, since particles damage metal and soft seats alike.

For service, the packing is a self-adjusting V-ring set and is the part most likely to need attention, followed by the soft seal on the plug where fitted. Keep a spare packing and body gasket for each installed size. Because valve and actuator are separate, the actuator can be removed without opening the pipeline, which makes inspection much easier.

Typical Type 3321 applications in Oman and the GCC

Valves in this class are used on utilities rather than main process lines. In desalination and power plants they control cooling water, condensate, auxiliary steam and chemical dosing lines. In oil and gas facilities and petrochemical plants they appear on heat-exchanger bypasses, seal-flush lines and steam tracing headers, and in district cooling and large buildings they regulate chilled and hot water.

With +300 °C capability, stainless steel bodies for corrosive duty and a soft seat for tight shut-off, the Type 3321 covers many situations without moving to a heavier valve class. In Gulf sites the choice of electric or electropneumatic actuator often follows the availability of clean dry instrument air.

Type 3321 and related V2001 valves

The Type 3321 is the straight globe valve of the Series V2001. The Type 3323 is the three-way mixing and diverting valve of the same series, and the Type 3531 is a related version for heat transfer oil with a bellows seal. Seven Star LLC can quote the valve, the actuator and a positioner together if you describe the duty.

Information to send with an RFQ for the Type 3321

• Nominal size, pressure rating and flange standard.
• Medium, minimum and maximum flow, inlet and outlet pressure, and temperature.
• Required KVS or the sizing data, and the seat type.
• Actuator version (IP, PP, E1, E3), supply air or voltage, and fail-safe direction.
• Accessories: positioner, limit switch, resistance transmitter or insulating section.
• Quantity and delivery site.

Documents and quotation

A SAMSON datasheet (T 8111) for the DIN version is attached on this page with materials, KVS tables, differential-pressure tables and dimensions.

Send the process data and actuator preference to Seven Star LLC and we will confirm the correct build and prepare a quotation.