Samson Type 3354 On/Off Globe Valve DN 15-80, PN 16

Samson Type 3354 pneumatic on/off globe valve for utility lines

The Samson Type 3354 is a straight-pattern (T-pattern) globe valve with a soft-seated flat plug and a pneumatic piston actuator, designed for simple open/close duty. It is made in nominal sizes DN 15 to 80 with a cast iron body EN-GJL-250, flanged connections, PN 16 and a permissible medium temperature of –10 to +180 °C. Seven Star LLC supplies the Type 3354 in Oman and the GCC as an independent supplier in Muscat, mainly for utility, steam and compressed-air isolation where a robust, serviceable automatic shut-off valve is needed rather than a modulating control valve.

The datasheet lists water, air, neutral gases and liquids, oils and steam up to 180 °C as permissible media. Two design points keep service costs down: the soft seal is replaceable, and the actuator springs can be relieved safely without a spring compressor, which removes one of the common hazards of working on spring-return actuators.

Reading the Type 3354 version and fail-safe action

The 3354 has a single body style, so the selection effort goes into the actuator and the fail-safe direction. The piston actuator is available with an effective area of 30, 60 or 120 cm² (63, 90 or 125 mm piston diameter), and the spring arrangement gives one of two safe positions when the supply air or the control signal fails.

Type 3354 technical specifications

How the Type 3354 works

The medium flows through the valve in the flow-to-open direction shown by the arrow on the body. The plug position sets the cross-section between seat and plug. With an on/off valve the plug is either on the seat or lifted over the full 15 mm travel, so the flow coefficient listed for the nominal size applies in the open position. The soft seal gives tight shut-off, while the PTFE/carbon packing seals the stem.

The actuator materials depend on size: the 30 and 60 cm² actuators use glass-fibre reinforced PA 66 for cover and piston with a spheroidal graphite iron base, while the 120 cm² actuator is aluminium. Whether a given actuator can close the valve against the line differential pressure depends on the signal pressure and fail-safe direction; Samson gives tables for this in the datasheet and the correct actuator should be confirmed against the actual maximum differential pressure.

Accessories and related Samson parts

The accessory list in the datasheet covers the Type 4740 electric limit switch with inductive proximity switches or microswitches, optionally combined with a 3/2-way solenoid valve for up to 7 bar, a holder for M12 proximity switches, and a NAMUR adapter for mounting a solenoid valve on the 30 and 60 cm² actuators. A 3/2-way solenoid valve with G 1/8 connection (nozzle 1.5, 0 to 12 bar, 24 V DC or 230 V AC, optional silencer) can be attached directly. For larger valves DN 65 and 80 an angular screw joint is listed. Related types on this site include the Type 4740 and Type 3963 and the Type 3241 modulating globe valve for continuous control.

Selection checklist for a Type 3354

• Confirm the medium is on the permitted list and that steam does not exceed 180 °C.
• Pick DN from the required KVS and the maximum flow velocity (3 m/s for liquids, 0.3 Mach for gases).
• Check that PN 16 and the cast iron body meet the piping class and local pressure-equipment rules.
• Decide fail-close or fail-open for the safe position.
• Choose the actuator area (30, 60 or 120 cm²) against the maximum differential pressure and the supply air pressure available (maximum 8 bar).
• Specify limit switches and solenoid valve voltage, and whether a silencer is needed.
• Ask for the ANSI version or other body materials if the project requires them; both are available on request.

Installation, commissioning and maintenance of the 3354

Mount the valve with the flow arrow in the flow direction, support the pipework so that its weight does not load the cast iron body and check that the actuator can be reached for spring relief. On commissioning, cycle the valve several times with the actual supply air, check opening and closing times with the solenoid fitted and confirm the limit switch indications at both end positions. Because the seal is a replaceable soft seal, annual inspection of the seat insert and packing in steam duty is usually enough to keep leakage low.

Typical applications of the Type 3354 in Oman and the GCC

An automatic on/off valve of this size suits utility services in power and desalination plants (service water, instrument air headers, low-pressure steam tracing and heating), skid-mounted packages in oil and gas, and building or district-cooling plants where long cooling-water lines need remote isolation. In hot, dusty and humid conditions the polymer and aluminium actuator housings and the PTFE seal give good resistance, although direct sun on a black actuator cover should be taken into account when judging ambient temperature against the 60 °C limit.

Information to send with your Type 3354 RFQ

• Medium, temperature and pressure, including steam conditions if used.
• Required DN or KVS and maximum differential pressure.
• Fail-safe direction and available air supply pressure.
• Solenoid valve voltage and any limit switch or proximity switch requirements.
• Flange standard, and ANSI or alternative body material if needed.
• Quantity, tag list and delivery site.

Documents and quotation

The Samson data sheet T 8140 for the Type 3354 is attached on this page. Send your duty data and the version you need, and we will confirm availability and lead time. Seven Star LLC is an independent supplier and does not claim any official status with the manufacturer.