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Brand: Swagelok
Swagelok SS-20VS4 Vee-Stem Needle Valve, 0.21 Cv, 1/4 in. Tube
Description
The Swagelok SS-20VS4 is a 20 series vee-stem needle valve with 1/4 in. Swagelok tube-fitting ends, so it drops straight into an instrument tubing run without any thread work. A metal vee stem seats on a metal seat, which allows the 20 series to use its full temperature and pressure rating, and it is fitted with a stainless steel bar handle.
Technical specifications
| Parameter | Specification |
|---|---|
| Part number | SS-20VS4 |
| Description | Integral-bonnet needle valve, vee stem, straight pattern |
| Series | 20 |
| Body material | 316 stainless steel |
| Connections | 1/4 in. Swagelok tube fitting x 1/4 in. Swagelok tube fitting |
| Flow coefficient Cv | 0.21 |
| Orifice | 0.125 in. (3.2 mm) |
| Stem type / tip | Vee, 316 stainless steel |
| Handle | Stainless steel bar handle |
| Working pressure at 100 F (37 C) | 6000 psig (413 bar), subject to tubing rating |
| Catalog dimension A | 2.46 in. (62.5 mm) |
| Pressure at 450 F (232 C) | 4130 psig (284 bar) for the 20 and 26 series table |
| Cleaning | Standard cleaning and packaging SC-10 |
Vee stem and tube ends
A vee stem has a short conical tip that closes quickly, in fewer turns than a regulating stem, and suits shutoff and coarse flow control. With a 0.125 in. orifice and a Cv of 0.21, the SS-20VS4 handles more flow than the soft-seat SS-20KF4 and uses the same 20 series body. The tube-fitting ends make it 2.46 in. long, longer than the 1.88 in. of the female NPT version SS-20VF4 because the Swagelok nuts and ferrules are added to each end.
Since the ends are tube fittings, the working pressure of the assembled valve is limited by the tubing used: the catalog notes that the valve body rating of 6000 psig applies to valve ends and refers to the Tubing Data catalog for tube-fitting end connections.
Temperature and packing
The 20 and 26 series rate 316 stainless steel at 6000 psig from -65 F to 100 F, then 5160 psig at 200 F, 4660 psig at 300 F and 4130 psig at 450 F. The catalog lists ratings up to 600 F, but limits temperatures according to packing: 450 F with standard PFA packing, 600 F with the PEEK packing option and 250 F with UHMWPE. When your service goes above 450 F, specify the PEEK packing option at order.
All integral-bonnet needle valves are cleaned to SC-10 and tested with nitrogen at 1000 psig; the data page lists Low Emissions certification.
Selecting between the 20 series variants
SS-20VS4 is vee stem with tube ends. SS-20VF4 is the same stem with female NPT ends, and SS-20KF4 is the PCTFE soft-seat stem. The 26 series, such as SS-26VS6, takes a larger 0.250 in. orifice at 0.73 Cv for 3/8 in. and 1/2 in. connections. Match the end type to the line and the stem to the shutoff requirement.
Make up the tube ends in the standard way, with annealed tube seated on the shoulder and one and one-quarter turns of each nut from finger-tight, then check pull-up with the Swagelok gap inspection gauge. Support the tubing so the weight of the valve is not carried by the ferrules alone.
Documents and quotation
This page links the official Swagelok integral-bonnet needle valves O, 1, 18, 20 and 26 series catalog MS-01-164 (EN), which holds the ordering tables, ratings and materials behind the figures above. Seven Star LLC is an independent supplier in Muscat; for a quotation on SS-20VS4, tell us the quantity and any option you need, such as handle, packing or special cleaning.
Before ordering, please confirm the part number, tube size and thread type against the attached catalog, as nearby codes differ by one character. Related items: product category.
Datasheets & Documents
- Catalog Swagelok integral-bonnet needle valves O, 1, 18, 20 and 26 series catalog MS-01-164 (EN) Download
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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.
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Frequently Asked Questions
What are the connections on SS-20VS4?
1/4 in. Swagelok tube-fitting ends on both sides.
What is the Cv and orifice?
Cv of 0.21 with a 0.125 in. (3.2 mm) orifice.
What type of stem does it use?
A 316 stainless steel vee stem on a metal seat.
What pressure rating can I rely on?
The 20 series body is rated 6000 psig at 100 F; with tube ends the tubing rating also applies, so take the lower.
How does it differ from SS-20KF4?
SS-20KF4 has a soft PCTFE tip, a smaller orifice and female NPT ends; SS-20VS4 has a vee stem, a larger orifice and tube-fitting ends.
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