Samson 2404-2 Tank Excess Pressure Valve with Pilot

Samson 2404-2 pilot-operated tank excess pressure valve

The Samson Type 2404-2 is an excess pressure valve for inert gas blanketing of storage tanks. Where the 2404-1 feeds gas in, the 2404-2 lets gas out: it opens when the tank pressure rises above the adjusted set point and vents or returns the surplus until the blanket pressure is stable again. It is used for oxidation-sensitive, toxic or explosive products, and the controlled "breathing" it provides keeps the tank within safe limits while limiting inert gas losses and emissions. Seven Star LLC supplies Samson 2404-2 valves in Oman and the GCC as an independent supplier in Muscat.

According to the manufacturer data sheet (T 2540 EN, December 2025) the 2404-2 is a regulator assembly with four parts: the main valve, a Type 2406 pilot valve with ½ NPT female connection, a Type 2441 input pressure regulator, and the M2404 mounting kit with hook-up and needle valve. Two main valve designs cover the size range, the Type 2406 for NPS 2½ to 6 and the Type 2422 with Type 2420 actuator for NPS 8 to 16.

Technical specifications of the Type 2404-2

How the 2404-2 relieves excess blanketing pressure

The input pressure regulator takes the supply pressure and reduces it to a fixed input pressure for the pilot valve, so the pilot behaves consistently even when the supply varies. The pilot valve compares the tank pressure p1, which reaches it through a control line, with the force of its set point spring. At rest the spring keeps the pilot closed.

When the blanketing gas pressure in the tank rises above the set point, the pilot opens and the control pressure on the main valve diaphragm builds up. As soon as this force exceeds the closing spring, the main valve opens and the gas is vented to atmosphere or recovered for processing. When the tank pressure falls back to the set point the valve closes with a soft seat. A lead-sealed needle valve, adjusted at the factory, stabilises the loop.

Main valve sizes and flow coefficients for the 2404-2

The large sizes use the Type 2420 actuator, 320 cm² for NPS 8 and 10 and 640 cm² for NPS 12 and 16. Permissible differential pressure is 12 bar for the Type 2406 sizes, 10 bar for DN 200 and 250, and 6 bar for DN 300 and 400. A DN 125 version with KVS 250 also appears in the data sheet.

Materials and variants

Bodies are available in A126B, A216 WCC or A351 CF8M (EN-GJL-250, 1.0619 or 1.4408). Seat and plug are 316L (1.4404) on the Type 2406, while the Type 2422 uses CF3M (1.4409) in NPS 8 and 10 and 304 or 410 in NPS 12 and 16. Plug seal and diaphragms are EPDM, NBR or FKM. Special versions listed by Samson are FDA-compliant materials for food and pharmaceutical use, sour gas service (NACE), and a pilot actuator with seal and leakage line for flammable gases.

Using the 2404-2 with the 2404-1 on one tank

A blanketing tank needs two actions: add gas when the pressure falls and release gas when it rises. The Samson 2404-1 pressure reducing valve covers the first, and the 2404-2 covers the second. Their set points are normally staggered, with the reducing valve slightly below and the excess pressure valve slightly above the nominal blanket pressure, so they never work against each other. Note the 2404-2 reaches larger sizes (up to NPS 16) than the 2404-1 because the venting path must pass the full filling flow.

Selection and ordering checklist for the 2404-2

• Maximum filling and thermal expansion flow to be vented, to choose the nominal size and CV or KVS.
• Set point in mbar and the matching pilot range from the four available.
• Flange standard and rating, with the length L1 from the data sheet checked against the pipe run.
• Gas composition and temperature, to select EPDM, NBR or FKM and the body material.
• Whether the vented gas goes to atmosphere or to a recovery or flare header, which affects back pressure.
• Availability of compressed air or inert gas for the input pressure regulator.
• Special requirements: NACE, FDA, leakage line connection, painting and documentation.

Installation and maintenance of the 2404-2

The unit is supplied pre-assembled. Mount the main valve in the vent line from the tank with the flow direction matching the arrow, run the ½" control line to the tank vapour space for the upstream pressure, and connect the supply to the input regulator. Allow space for the set point adjuster and for lifting heavy sizes, since the NPS 16 version weighs about 670 kg. Commission by raising the tank pressure slowly and confirming the valve opens at the set point and closes tightly. Maintenance is limited to inspecting diaphragms, seat and plug seals, and the control line tubing for blockage by condensate or product vapour.

Typical applications in Oman and the GCC

High daytime temperatures expand the vapour space of tanks and push pressure upward, so excess pressure valves are working equipment, not just protection. The 2404-2 suits chemical and petrochemical storage, oil and gas additive and condensate tanks, and industrial gas or solvent storage at ports and utilities. Because it can route gas to a recovery system, it also supports emission targets at sites that want to avoid venting inert gas and hydrocarbons to the atmosphere.

Information to send with your RFQ for the 2404-2

Provide the tank design pressure, blanketing set point, maximum vent rate, line size and flange rating, gas and temperature, destination of the vented gas, supply medium and any special material requirement. Quantity and delivery location complete the enquiry.

Documents and quotation

A Samson datasheet for the 2404-2 (T 2540 EN) is attached on this page. It holds the set point ranges, flow coefficients, material tables and dimensions for every size.

Send the part number 2404-2 with your tank data and we will prepare a quotation for Oman and the GCC.