Brand: Swagelok

Swagelok SS-18RF6 Needle Valve, 1.80 Cv, 3/8 in. FNPT

Name: Swagelok SS-18RF6 Needle Valve 3/8 in. FNPT | Seven Star LLC
Brand: Swagelok
SKU: SS-18RF6

Description

Where the 1 series needle valve is too small for the flow, the 18 series steps up. The Swagelok SS-18RF6 is the 3/8 in. female NPT version: a 316 stainless steel integral-bonnet needle valve with a regulating stem, a 0.375 in. orifice and a flow coefficient of 1.80, fitted with an anodised-aluminium bar handle that gives a firm grip for gloved hands and larger packing torque.

Technical specifications

Parameter	Specification
Part number	SS-18RF6
Description	Integral-bonnet needle valve, regulating stem, straight pattern
Series	18
Body material	316 stainless steel
Connections	3/8 in. female NPT x 3/8 in. female NPT
Flow coefficient Cv	1.80
Orifice	0.375 in. (9.5 mm)
Handle	Aluminium bar handle, handle pin steel
Working pressure at 100 F (37 C)	5000 psig (344 bar)
Pressure at 450 F (232 C)	3435 psig (236 bar)
Catalog dimension A	3.00 in. (76.2 mm)
Flow pattern	Straight (2-way)
Low emissions	Certified, as listed on the Swagelok data page
Cleaning	Standard cleaning and packaging SC-10

The step up from the 1 series

The 18 series keeps the compact bonnet and live-loaded packing of the smaller valves but uses a larger orifice, 0.375 in. against 0.250 in., which raises the maximum Cv from 0.73 to 1.80. The catalog lists the series in 3/8 in., 1/2 in. and 3/4 in. connections, with 18RF6 as the 3/8 in. female NPT version. The packing uses three disc springs, where the smaller bodies use two, to keep the load on the stem packing over the larger stem diameter.

The bar handle replaces the round handle used on 1 series valves. It is a steel pin and anodised aluminium handle, which the catalog gives as standard for the 18 series.

Pressure, temperature and test data

Rating for 316 stainless steel is 5000 psig (344 bar) from -20 F to 100 F, with a stepped reduction to 4295 psig at 200 F, 3715 at 350 F and 3435 psig at 450 F. These are the same pressure-temperature ratings as the 1 series and are tied to the PFA packing, so confirm the limits for any other packing. All integral-bonnet needle valves are shell tested and seat-tested with nitrogen at 1000 psig with a seat leakage limit of 0.1 std cm3/min.

The catalog describes the API 624 low-fugitive-emissions test, run at a third-party lab on rising-stem valves, and the Swagelok data page marks the part as certified.

How to specify it

SS-18RF6 reads stainless steel, 18 series, regulating stem, female NPT and 6 for the 3/8 in. pipe size. If you need male NPT or tube-fitting ends, change F to M or S, and the last number to 8 for 1/2 in. or 12 for 3/4 in., as in SS-18RS8 and SS-18RS12. Panel mounting, vee and soft-seat stems and other handle styles are options in the same catalog.

It suits sampling, instrumentation and process lines where a larger throttling valve is needed; check the Cv at your pressure drop and, for gases, whether flow is choked. Do not substitute this valve for a shutoff in safety-instrumented service without your own assessment.

Documents and quotation

Source document: Swagelok integral-bonnet needle valves O, 1, 18, 20 and 26 series catalog MS-01-164 (EN), attached for download. It carries the tables this summary draws on. To get a quote for SS-18RF6, reply with the quantity and any options, and we will check the code against the document first. Seven Star LLC is an independent supplier in Muscat.

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About brand

Two-ferrule tube fittings made Swagelok a familiar name on instrument air headers, impulse lines and analyzer sample systems. The company has made fluid system components since 1947 and is based in Solon, USA. Seven Star LLC sources and supplies Swagelok tube fittings, ball valves, needle valves, quick-connects, face seal fittings and pressure regulators for plants in Oman, checking every ordering number against the manufacturer's catalog before an offer is made.

Swagelok product families listed here

The items on this page cover the small-bore components an instrument technician handles most often. Swagelok tube fittings join metric and fractional tubing without threading or welding. Swagelok ball valves are represented by the 40 series, the 40G series one-piece instrumentation ball valve (for example SS-43GS4) and the three-way pattern listed as 40GX. The SS-1RS4 is an integral bonnet needle valve from the 1 series. VCR metal gasket face seal fittings serve high-purity and vacuum lines, QC series quick-connects are used where lines are coupled and uncoupled often, and the KPR series is a pressure-reducing regulator.

Where Swagelok components are used

Typical duties are transmitter hook-ups, manifolds and impulse tubing, analyzer shelters and sample conditioning panels, chemical injection skids, gas cylinder panels in laboratories, and test benches. In oil and gas service across the GCC, the usual questions are material grade, pressure rating at temperature and, for sour service, whether the manufacturer offers the item to NACE MR0175 requirements.

Ordering Swagelok fittings and valves: what we need

A Swagelok ordering number carries most of the specification. In SS-43GS4, SS is 316 stainless steel, 43G identifies the valve series and size, and S4 is a 1/4 in. Swagelok tube fitting end connection. Send the complete ordering number including any suffix for handle, seat or cleaning option. If you do not have it, give us the tube outside diameter and wall thickness, body material, end connections on each port, working pressure and temperature, and the fluid. For a KPR regulator we also need inlet pressure, the outlet control range and the port configuration.

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