Samson 2406 Excess Pressure Valve DN 15-50 PN 16-40

Samson 2406 excess pressure valve for tank blanketing and gas pressure control

The Samson 2406 is a self-operated excess pressure valve, also called a back-pressure or pressure relief regulator. It holds the pressure upstream of the valve at a set value by opening when that pressure climbs above the setting and staying shut below it. No compressed air, electricity or positioner is needed, because the process pressure itself drives the actuator. The 2406 is a proportional regulator in the DIN version of the Samson self-operated range, with nominal sizes from DN 15 to DN 50, pressure ratings PN 16, 25 and 40 and set points from 5 mbar up to 10 bar. Seven Star LLC supplies Samson 2406 valves in Oman and the GCC as an independent supplier based in Muscat.

The typical job for a 2406 is to keep a nitrogen blanket on a storage or reaction tank just above atmospheric pressure, venting surplus gas when the tank fills. It is equally at home on fuel gas headers feeding boilers, dryers, vaporizers and industrial furnaces, and on compressed air supplies in process plants.

Understanding the Type 2406 designation

Samson does not use a long structured code for this valve. The number identifies the regulator function, and the exact build is defined by the ordering text on the data sheet. For a 2406 you therefore specify these items:

• Type 2406 – excess pressure valve, opens when upstream pressure rises (the counterpart of the Type 2405 reducing valve, which closes when downstream pressure rises).
• Nominal size – DN 15, 20, 25, 32, 40 or 50; larger sizes on request.
• Set point range – one of nine continuously adjustable ranges between 5 mbar and 10 bar.
• Body material and pressure rating – cast iron, spheroidal graphite iron, cast steel or stainless steel, in PN 16, 25 or 40.
• KVS coefficient and optional special versions such as FDA, NACE or leakage line.

Samson 2406 technical specifications

How the Type 2406 regulates pressure

Medium flows through the valve in the direction of the arrow cast on the body, and the plug position sets the free area between plug and seat. With no pressure on the control line, the set point springs keep the plug on its seat. The pressure to be controlled is tapped upstream of the valve, normally through an external control line, and led to the connection on the actuator housing. There it acts on the operating diaphragm and produces a force against the springs. When that force exceeds the spring force you set with the adjuster on top of the actuator, the plug lifts and the valve opens proportionally to the pressure rise.

On larger flow coefficients (KVS 6.3 to 32) a balancing diaphragm cancels the effect of inlet and outlet pressure on the plug, so the setting is not pushed around by changes in the pressure drop. As with every proportional regulator, a small offset from the set point appears as flow increases. Selecting a valve with enough capacity keeps that offset small.

Set point ranges and actuator sizes for the 2406

The lower the set point range, the larger the diaphragm needed to generate enough force. The data sheet pairs each range with an actuator area, and each area has its own limit on pressure at the diaphragm.

The weight of a complete 2406 depends mainly on the actuator: about 8 to 9 kg for DN 15 to 25 with the small actuators, rising to roughly 28 kg in DN 15 to 25 and 40 kg in DN 32 to 50 for the 5 to 15 mbar range. A cast steel body adds about 10 percent. Build height runs from around 318 mm to 489 mm, with overall lengths of 130 mm (DN 15) to 230 mm (DN 50). Leave at least 150 mm above the actuator for removal and service.

Where the 2406 fits: blanketing, fuel gas and related Samson regulators

For tank blanketing the 2406 is paired with a Type 2405 pressure reducing valve. The 2405 feeds inert gas into the tank when tank pressure falls below its set point, and the 2406 vents the excess when pressure rises above its own, so the tank sits in a narrow band just above atmosphere. This arrangement keeps product away from oxygen and moisture and limits inert gas consumption.

Related parts in the same self-operated family include the Type 2405 reducing valve, the Series 44 steam and gas regulators such as 44-0 B, 44-1 B and 44-2, and the Type 2371 hygienic reducing valve. For a differential or flow-based task, the pressure-independent Type 2488/2489 is the better fit. Tell us the duty and we can point you to the right type.

Selection and ordering checklist for the 2406

• Confirm the function: upstream pressure holding (2406) rather than downstream reduction (2405).
• State the medium, its temperature range and whether it is flammable, since this drives body material, diaphragm and seal choice.
• Give the set point and the allowed deviation, so the right range and actuator area can be chosen.
• Provide the maximum flow and the inlet pressure so the KVS can be checked; reduced KVS values from 0.1 to 20 exist for tight control.
• Specify nominal size, PN class and flange standard of the mating pipe.
• Ask for special versions where needed: FDA, NACE for sour gas, leakage line connection or direct pressure tapping.

Installing and maintaining the 2406

Mount the valve with the actuator on top in a pipe that falls slightly to both sides, so condensate drains away. Check that the flow arrow matches the process direction and leave room for service. The control line is not part of the delivery and must be built to site conditions. Where the blanketing gas can condense, slope the control line about 10 percent back towards the tank connection so liquid runs back into the vessel instead of collecting at the diaphragm.

The regulator needs little attention. During planned shutdowns, inspect the diaphragms for ageing, check the plug soft seal and seat for damage, and confirm the set point with a gauge. Keep a spare diaphragm and seal kit for critical tanks, quoting the full type, size and serial data from the nameplate.

Typical applications in Oman and the GCC

In the Gulf region, the 2406 suits blanketing of chemical, solvent and fuel storage tanks in refineries, terminals and petrochemical sites, where the tank breathes with daily temperature swings and product transfers. It also regulates fuel gas pressure at burners and heaters in power and desalination plants and holds back-pressure on compressed air or nitrogen headers. High ambient temperature, dust and humidity make the choice of diaphragm material and the routing of the control line worth attention; stainless steel bodies are common in coastal installations.

Information to send with an RFQ for the 2406

• Medium, composition and temperature range
• Required set point, with unit (mbar or bar gauge)
• Maximum and minimum flow, inlet pressure and outlet conditions
• Nominal size, PN rating, flange standard and body material
• Diaphragm and seal material, and any special version
• Project name, tag number and delivery location

Documents and quotation

A Samson datasheet for the Type 2406 is attached on this page, covering set point ranges, materials, dimensions and the ordering text. Please confirm the exact version you need against it before ordering.

Send the duty data above and Seven Star LLC will prepare a quotation for the Samson 2406 for delivery in Oman and the GCC.