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Brand: Swagelok
Swagelok SS-DLS4 DL Series Diaphragm-Sealed Valve
Description
Packless diaphragm valve for high-purity, high-pressure lines
The Swagelok SS-DLS4 is a 316L stainless steel diaphragm-sealed valve from the DL series, with 1/4 in. Swagelok tube fitting ends and a lever handle that moves the valve from fully open to closed in a quarter turn. Process fluid is contained by a stack of metal diaphragms, so there is no stem packing to leak, which suits high-purity gas delivery, specialty and corrosive gas panels, analyzer sample systems, semiconductor and research gas lines, and any service where external leakage and dead volume must be minimised.
A position indicator ring shows whether the valve is fully open or closed, and a splined handle and actuator prevent slippage. The stem tip is a contained soft seat, so shutoff is repeatable. The valve is rated from vacuum to 3500 psig.
Technical specifications
Data are from Swagelok catalog Diaphragm Valves, DL and DS Series (MS-01-73, Rev O, January 2023) and the Swagelok product page for SS-DLS4.
| Parameter | Specification |
|---|---|
| Ordering number | SS-DLS4 |
| Series | DL series, quarter-turn lever handle, straight (2-way) pattern |
| End connections | 1/4 in. Swagelok tube fittings, both ends |
| Orifice | 0.156 in. (4.0 mm) |
| Flow coefficient (Cv) | 0.14 |
| Pressure rating at 70 F (20 C) | 3500 psig (241 bar) |
| Back pressure maximum at 70 F | 1500 psig (103 bar); 2500 psig (172 bar) with the optional 17-7 PH spring (add -PS) |
| Temperature range | -100 to 250 F (-73 to 121 C) |
| Working pressure at temperature | 3500 psig (241 bar) up to 100 F; 2950 psig (203 bar) at 200 F; 2800 psig (192 bar) at 250 F |
| Internal volume | 0.18 in.3 (2.9 cm3) maximum, with tube fitting ends |
| Body | 316L stainless steel (A479) for tube fitting ends |
| Diaphragms | Three 316 stainless steel diaphragms (A240) |
| Stem tip and seat | Fully contained PCTFE soft-seat stem tip (PTFE or polyimide optional) |
| Gasket | PTFE-coated 316L stainless steel |
| Handle | Green aluminum lever handle (2024-T4, epoxy coated); other colors by suffix |
| Surface finish | 20 microinch (0.51 micrometre) Ra average, machine finished |
| Cleaning | Special cleaning and packaging SC-11 as standard; ultrahigh-purity SC-01 with suffix -P (8 microinch Ra, electropolished) |
| Helium leak test | Inboard leak rate 4 x 10-9 std cm3/s |
Related DL and DS ordering numbers
The DS series is the handle-operated sibling, needing about one and one-half turns and offering a higher Cv of 0.30. Typical ordering numbers from the catalog are listed below.
| Ordering number | Configuration |
|---|---|
| SS-DLS6 / SS-DSS6 | 3/8 in. tube fittings, DL / DS series |
| SS-DLS6MM / SS-DLS8MM | 6 mm / 8 mm tube fittings, DL series |
| SS-DSS4 | 1/4 in. tube fittings, DS series (Cv 0.30) |
| 6LV-DLBW4 | 1/4 in. tube butt weld ends, DL series |
| SS-DLTW4 | 1/4 in. socket and 3/8 in. butt weld ends |
| SS-DLV51 / SS-DLVCR4 | Female / male VCR face seal fittings |
| SS-DLVCO4 | VCO O-ring face seal fitting |
| SS-DLM4F4A | 1/4 in. male by female NPT |
Selection notes
Choose the end connection first: tube fittings suit serviceable panels, while butt weld, VCR and VCO ends are used where metal gasket or welded joints are specified. Add -P for the ultrahigh-purity process with an 8 microinch Ra finish. Handle colors (black, blue, orange, red, white, yellow) are added as suffixes and green is standard. Swagelok notes that bottom and panel mounting are standard on the valve, and multiport, elbow and monoblock manifold versions are covered in a separate catalog (MS-02-442). Apply only the torque needed for positive shutoff on the DS series, and review oxygen service hazards in report MS-06-13 before specifying for oxygen. Where a bellows-sealed design is preferred, see the Swagelok SS-4H bellows-sealed valve.
Documents and quotation
The attached catalog includes the flow curve, pressure-temperature table, cleaning process specifications, dimensions and replacement kits (stem kit 6L-3AK-DS-KF, diaphragm kit SS-3DK-DS). Before ordering, confirm the gas or fluid, pressure and temperature, cleaning level and whether panel mounting is required. Send the ordering number and quantity for a quotation; related items are listed under Fittings and Valves.
Datasheets & Documents
- Catalog Swagelok Diaphragm Valves DL and DS Series catalog (MS-01-73, Rev O, 01/2023) 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 is the pressure rating of the SS-DLS4?
3500 psig (241 bar) at 70 F, derated to 2950 psig (203 bar) at 200 F and 2800 psig (192 bar) at 250 F.
How many turns does the DL series need to operate?
Only a quarter turn of the lever handle moves the valve from fully open to closed.
What is the flow coefficient of the SS-DLS4?
The DL series has a Cv of 0.14 and a 0.156 in. (4.0 mm) orifice. The DS series reaches 0.30 Cv.
Is an ultrahigh-purity version available?
Yes. Adding -P to the ordering number gives the SC-01 ultrahigh-purity process with an 8 microinch Ra electropolished finish.
Can the back pressure rating be increased?
Yes. A 17-7 PH spring raises the back pressure limit from 1500 to 2500 psig and is ordered by adding -PS.
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