Brand: Swagelok

Swagelok SS-4R3A1 Proportional Relief Valve, MNPT x 1/4 in. Tube

Name: Swagelok SS-4R3A1 Proportional Relief Valve | Seven Star LLC
Brand: Swagelok
SKU: SS-4R3A1

Description

The Swagelok SS-4R3A1 is an R3A series high-pressure proportional relief valve. Its 1/4 in. male NPT inlet screws into a port or tee, and its 1/4 in. Swagelok tube fitting outlet carries the relieved fluid away through tubing. A proportional relief valve opens gradually as pressure rises above the set pressure, so it protects instruments, gauges and small vessels from overpressure without the full-lift pop of a safety valve. The R3A series handles set pressures from 50 to 6000 psig (3.4 to 413 bar) with a choice of springs.

Technical specifications

Parameter	Specification
Part number	SS-4R3A1
Description	High-pressure proportional relief valve, no handle
Series	R3A
Body material	316 stainless steel
Connections	Inlet 1/4 in. male NPT; outlet 1/4 in. Swagelok tube fitting
Set pressure range	50 to 6000 psig (3.4 to 413 bar), by spring selection
Inlet working pressure	6000 psig (413 bar); up to 8000 psig (551 bar) during relief
Outlet working pressure	1500 psig (103 bar)
Seal material	Fluorocarbon FKM (other seals optional)
Set pressure repeatability	+/- 3 psig (0.20 bar) or +/- 5 percent, whichever is greater, at 60 to 80 F
Cleaning	Standard cleaning and packaging SC-10

Proportional relief, not a safety valve

A proportional relief valve opens gradually as the pressure rises above the set pressure and closes as it falls below it, so it does not have a capacity rating at a given accumulation. The Swagelok catalog is explicit that these valves are not certified to ASME or any other code and must not be used as ASME Boiler and Pressure Vessel Code safety relief devices; they are also not safety accessories as defined by the Pressure Equipment Directive 2014/68/EU. The system designer decides where a code-stamped device is required.

That makes them well suited to protecting gauges, transmitters, pump discharge lines and hydraulic test circuits, where a controlled bleed-off is what is needed.

Springs, set pressure and back pressure

In the R3A series you select and install the spring that covers the required set pressure and apply the matching label to the cap, or order the valve factory-set to a specified pressure. Set pressure is the upstream pressure at which the first indication of flow occurs; repeatability after initial relief is plus or minus 3 psig (0.20 bar) or 5 percent, whichever is greater, at 60 to 80 F. The effect of back pressure is minimized in the high-pressure designs, and a quad seal eliminates leakage around the stem during relief.

Seal materials of FKM, Buna N, neoprene, ethylene propylene or perfluoro elastomer are available with temperature limits listed in the catalog; the maximum set pressure falls as temperature rises, to 4660 psig at 275 F for FKM in the R3A.

Ordering and comparison

In SS-4R3A1, SS is 316 stainless steel, 4 is 1/4 in., R3A is the series and the trailing 1 describes the end connections: male NPT inlet and Swagelok tube fitting outlet. The sister code SS-4R3A5 has a male NPT inlet and a female NPT outlet instead, and SS-4R3A5-RT uses ISO threads. Larger 1/2 in. models in the same catalog use the R4 series with a higher flow orifice.

State the required set pressure, fluid and temperature when you request a quotation, so the correct spring and seal can be selected.

Documents and quotation

Source document: Swagelok proportional relief valves R series catalog MS-01-141 (EN), attached for download, which carries the tables this summary draws on. To get a quote for SS-4R3A1, reply with the quantity and options, and we will check the code against the document first. Seven Star LLC is an independent supplier in Muscat.

Verify the model, rating and connection against your specification and the attached document before ordering. Related items: product category.

Datasheets & Documents

Catalog Swagelok proportional relief valves R series catalog MS-01-141 (EN) Download

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About brand

Swagelok is the American maker of tube fittings and small-bore valves, best known for its two-ferrule compression tube fitting. Fred A. Lennon and Cullen B. Crawford founded it in Cleveland, Ohio, in July 1947 as Crawford Fitting Company to make that fitting. Lennon bought the whole business and the patent in 1948, and the company has been based in Solon, Ohio, since the mid-1960s.

Seven Star LLC is an independent supplier in Muscat. We list Swagelok tube fittings, needle, ball, check, relief and metering valves, filters, regulators and sample cylinders, and supply them for instrument tubing and analyser systems in Oman and the GCC by exact part number.

Swagelok company profile

Established	July 1947, Cleveland, Ohio, as Crawford Fitting Company
Founders	Fred A. Lennon and Cullen B. Crawford; Lennon bought out Crawford in 1948
Headquarters	Solon, Ohio, since the mid-1960s
Product families	Tube fittings and adapters, face seal fittings, needle, ball, plug, check, relief and diaphragm valves, filters, regulators, quick-connects, sample cylinders and hoses

Milestones

1947: Fred A. Lennon and Cullen B. Crawford found Crawford Fitting Company in Cleveland in July.
1948: Lennon buys out Crawford.
Mid-1960s: Headquarters move to Solon, Ohio.

Swagelok products we list

Family	Models	Typical use
Tube fittings	Overview, SS-810-6 union, SS-810-3 tee, SS-810-9 elbow, SS-810-4 cross, SS-810-1-8 male connector, SS-810-7-8 female connector, SS-810-61 bulkhead, SS-12M0-6 metric union, VCR face seal	Leak-tight connections on instrument and process tubing
Needle and metering valves	SS-1RS4, SS-1RF4, SS-18RF6, SS-6NBS6, SS-20VS4, SS-4MG	Isolation and fine flow adjustment on instrument lines and sample systems
Ball and plug valves	40G, 40GX 3-way, 60 Series, 83 Series, P4T plug	Quick quarter-turn shut-off and switching
Check, relief and sealed valves	SS-4C-1, CH, R3A, RL3, SS-4BK bellows, SS-DLS4 diaphragm	Backflow prevention, overpressure relief and leak-free sealing for toxic or high-purity media
Filters, regulators, sampling	SS-4F-2, SS-4TF-7, KPR regulator, sample cylinders, QC quick-connects	Analyser sample conditioning and gas or liquid sampling

A Swagelok part number can be read directly. In SS-810-6, "SS" is 316 stainless steel, "810" means a 1/2 in. tube fitting (8 sixteenths of an inch, 10 series), and "-6" is a union. A suffix such as "-8" adds a 1/2 in. NPT end, and "M0" marks metric tube, as in SS-12M0-6 for 12 mm. Tube fittings must be made up the same way every time: finger-tight, then 1 1/4 turns for most sizes. A gap inspection gauge confirms the fitting has been pulled up.

Where Swagelok products are used

In Oman and the GCC, Swagelok fittings and valves are used on instrument impulse lines, analyser sample systems, hydraulic and pneumatic control tubing, chemical injection and gas sampling in oil and gas, refining, petrochemical, power and laboratory installations.

Ordering Swagelok products: what we need

Send the full Swagelok part number (for example SS-810-6 or SS-1RS4), the material, and the tube size in inches or millimetres. For valves, add the end connections and any options. For sample cylinders, add the volume, pressure rating and end configuration.

Facts checked against Swagelok company history, October 2026.

Browse Swagelok products by category: Pipes & Fittings, Regulators, Fittings & Valves.