Samson 3214 Balanced Globe Valve with Fail-safe Actuator

SAMSON Type 3214 pressure-balanced globe valve with fail-safe actuator

The SAMSON Type 3214 is a single-seated globe valve balanced by a corrosion-resistant metal bellows. Combined with an electric actuator that has a safety function, it forms a control valve for heating systems that must shut down on excess temperature or pressure. It covers DN 15 to DN 250, PN 16 to PN 40 and medium temperatures up to 220 °C, for water and steam. Seven Star LLC supplies SAMSON valves in Oman and the GCC as an independent supplier in Muscat.

The datasheet T 5869 describes two valve types together. The Type 3213 is the unbalanced version and the Type 3214 is the balanced one, so the 3214 is the choice when large differential pressures act on the plug. The control valves are tested by the German technical surveillance association TUV according to DIN EN 14597 and are defined as shut-off and control devices; the register number is available from the manufacturer on request.

Decoding the 3213 and 3214 type designations

The designation has two parts separated by a slash: valve first, actuator second.

Type 3214 technical specifications

How the balanced Type 3214 and its safety function work

Medium flows through the valve in the direction of the arrow, and the area between seat and plug is set by the position of the plug stem. In the Type 3214, the pressure upstream of the plug is transferred through a hole in the plug stem to the outside of the balancing bellows, while the downstream pressure acts on the inside. The forces created by the differential pressure on the plug cancel out, so a small actuator can position the plug against a large pressure drop.

The safety function sits in the actuator. If the supply voltage fails, or if the temperature or pressure limiting equipment interrupts the control signal, a safety mechanism releases compression springs and the valve closes. Because the valve can act as a shut-off device inside safety interlock circuits, the datasheet requires a strainer (for example Type 2 NI) upstream of the valve in those circuits, so debris cannot keep the plug off the seat.

KVS values and differential pressure for the Type 3214

From DN 65, the optional flow divider ST 1 reduces KVS to 38, 60, 95, 150, 210, 315 and 375 respectively. The unbalanced Type 3213 offers KVS 4 to 32 up to DN 50 with a much lower permitted differential pressure (10 bar for DN 15 to 25, 2.9 bar for DN 32 and 40, 1.6 bar for DN 50), which shows why the balanced 3214 is preferred for hot-water mains with high pressure drops.

Actuators that match the Type 3214

• Type 5827-A1 / -A2: electric actuators for DN 15 to 25 (A1) and DN 32 to 50 (A2).
• Type 3374-21: fail-safe electric actuator for DN 65 to 100.
• Type 3374-27: fail-safe electric actuator for DN 125 to 250.
• TROVIS 5725-310, -313, -320, -323: actuators with process controller for domestic hot water heating; the -313 and -323 are half-transit-time versions.
• TROVIS 5725-810 and -820: actuators with two PID control modules for heating and cooling applications.

Electric control is by three-step signals or, for positioner versions, 0/4 to 20 mA or 0/2 to 10 V. The standard Type 3214 and 3213 valves without the DIN EN 14597 test, paired with electric or pneumatic actuators, are covered by a different SAMSON datasheet (T 5868).

Selection and ordering checklist for the 3214

Sizing follows DIN EN 60534: calculate the required KVS, select DN and KVS from the table, check the permitted differential pressure, then check temperature and valve version, and finally choose the actuator. The ordering text asks for:

• Type designation, for example 3214/3374 or 3214/5827-A, and whether the valve is for steam.
• Version up to 220 °C: yes or no.
• DN, PN, KVS coefficient, maximum differential pressure and maximum temperature.
• Body material.
• Electric actuator details: control signal, supply voltage and electrical accessories.

Installation and servicing of the 3214 fail-safe valve

Install the valve with the actuator in the upright position; other mounting positions only on request. Where the medium temperature is between -10 and +5 °C, or in networks with a constant temperature above 135 °C using certain actuators, an intermediate insulating piece (1990-1712) is specified. Fit a strainer upstream, keep the bellows housing free of insulation that traps heat against the actuator, and test the safety action after commissioning by interrupting the signal.

Keep the mounting and operating instructions EB 5868/5869 with the plant documents. Typical spares are packing, guide-nipple seals and the plug assembly; give the serial number and valve size when requesting parts.

Typical uses of the 3214 in Oman and the GCC

District-heating style hot-water networks are less common in the Gulf than in Europe, but the 3214 still fits hotel and hospital heating, process heating loops in food and chemical plants, steam-to-water heat exchangers and sterilisation or humidification systems fed by steam. In desalination and power plants, it can serve auxiliary heating loops where an independent over-temperature shutdown is required. Dust and high ambient temperature make it important to check the actuator ambient limits and to protect actuators from direct sun.

Information for your 3214 RFQ

• Full designation (valve and actuator) and DN, PN.
• Medium (water or steam), temperature and pressure, flow and differential pressure.
• Safety function required: temperature or pressure limiter, fail-safe direction.
• Supply voltage and control signal.
• Existing nameplate data if replacing a valve.
• Quantity and delivery location.

Documents and quotation

The SAMSON datasheet T 5869 EN covering the Types 3213 and 3214 is attached on this page.

Send the designation, DN, PN and duty details and we will confirm what can be supplied in Oman and the GCC.