DQS15F Cryogenic Diverter(3Way)Valves

| Product Overview

The DQS15F is a three-way (3-Way) cryogenic diverter ball valve engineered for multi-port flow routing in deep-cryogenic systems operating from −196°C to +85°C. Where its five-way sibling (DQS15C) routes flow among five ports, the DQS15F uses a T- or L-port ball to switch cryogenic flow between a common inlet and two outlet branches (or the reverse) with a single quarter-turn (90°) rotation of the manual handle. This makes it the workhorse three-way switching device for cryogenic manifolds, portable tank outlet selection, and filling/vaporizing system changeover.

The valve is built for the full industrial gas spectrum—LOX (liquid oxygen), LIN (liquid nitrogen), LAr (liquid argon), and LNG (liquefied natural gas)—rated for working pressures up to 41.37 bar (600 psig). Its construction pairs a stainless steel body, ball, and stem with PCTFE seat rings and a brass seat, a combination that delivers structural strength, corrosion resistance, and the conformable, low-leakage sealing required at −196°C where metal-to-metal seats fail through differential thermal contraction.

Three structural features distinguish this model in field service. First, the anti blow-out stem is mechanically retained so the stem cannot be ejected by internal pressure—a critical safety requirement for pressurized liquefied-gas service. Second, the full bore (full port) flow path keeps the flow area through the ball equal to the line size, minimizing pressure drop and maximizing flow rate for cryogenic transfer. Third, and most distinctive, the valve integrates overpressure-protection provisions directly into its body: two threaded safety-valve ports on top and a rupture-disc port at the bottom allow a relief device to be mounted on the transfer line at the same point as the switching valve—consolidating flow control and pressure protection in one compact installation. The inner/outer union nut connections simplify assembly into pipework, and the anti-misalignment handle design with OPEN/CLOSE position indication ensures the handle cannot be fitted incorrectly and its position can be read at a glance.

The compact three-port body with long lever handle is designed for reliable, repeatable flow routing and changeover in cryogenic skids, manifolds, portable tanks, and filling stations, where space is limited and flow switching must be fast, clear, and safe.

| Working Principle

The Three-Way (Diverter) Principle:

Unlike a simple two-port on/off ball valve, the DQS15F's ball is configured as a T-port or L-port passage pattern connecting three ports. In the T-port configuration, the common inlet can be connected to either of the two outlets, or the two outlets can be connected to each other while the inlet is isolated. In the L-port configuration, rotating the ball by 90° shifts the flow from one outlet branch to the other—a true "diverter" action. This is the essence of the three-way switching principle: one compact valve replaces two or more two-way valves, reducing leaks, space, and cost in cryogenic manifolds.

Flow Position — Aligned Passages and Full Bore Flow:

When the handle is rotated to a selected position, the ball's passage aligns with the chosen ports, and flow passes through. The full bore (full port) design keeps the flow area equal to the line size, so the cryogenic liquid passes through with minimal turbulence and pressure drop—important for high-flow transfer where throttling would cause flashing and pressure loss. The PCTFE seat rings and brass seat press against the ball surface, forming the tight, low-leakage seal around the flow path that keeps the closed port dry and leak-free.

Closed / Isolated Position — Passages Turned Away:

When the ball is rotated to the isolating position, the solid face of the ball presents itself to the flow, and the seat rings seal against the ball's spherical surface, blocking flow through the closed branch while the selected branch remains open—or isolating the entire valve when fully closed. This gives the operator both flow diversion and isolation capability from a single handle.

Quarter-Turn Manual Operation and Position Indication:

The valve is operated manually: rotating the long lever handle through 90° moves the ball between positions. The anti-misalignment handle design ensures the handle can only be fitted in the correct orientation, and the OPEN/CLOSE position indication lets the operator confirm the flow path at a glance. The anti blow-out stem keeps the stem mechanically retained within the body under all operating pressures, preventing hazardous stem ejection.

Integrated Overpressure Protection — Safety-Valve and Rupture-Disc Ports:

A distinctive feature of the DQS15F is that its body integrates two threaded safety-valve ports on top and a rupture-disc port at the bottom. These allow a pressure-relief device (a spring-loaded safety valve and/or a rupture disc) to be mounted directly on the transfer line at the same point as the switching valve. In operation, if the line pressure rises to the safety valve's set point, the valve vents excess pressure; if pressure rises faster than the relief valve can handle—or to the rupture disc's burst pressure—the disc bursts and vents the line, protecting downstream equipment. This consolidation of flow control and pressure protection in one compact valve is especially valuable on portable tanks and transfer lines where mounting space is limited.

Leak-Proof Sealing at Cryogenic Temperature:

At −196°C, metal components contract at different rates, which is why the valve relies on PCTFE for its seat rings: PCTFE remains resilient and conformable at cryogenic temperatures, pressing tightly against the ball to seal even when the metal dimensions shift. The brass seat provides a stable, machined seating surface. Together they maintain the leak-tight switching that cryogenic manifolds require across the full −196°C to +85°C range.

|

 Factory Shoot

|

 Application Video

|

 Product parameters

| Data Sheet

|

Comment & FAQ

1:    What is the DQS15F and how is it different from the DQS15C?

A: The DQS15F is a three-way (3-Way) cryogenic diverter ball valve, while the DQS15C is a five-way (5-Way) diverter. Both use the same core technology—a quarter-turn ball valve with anti blow-out stem, full bore flow path, PCTFE seat rings, and brass seat, in a stainless body rated for −196°C to +85°C and up to 600 psig. They differ in port count and ball passage pattern: the 3-way valve switches flow between a common inlet and two outlet branches, while the 5-way valve routes flow among five ports. The DQS15F additionally integrates two safety-valve ports on top and a rupture-disc port at the bottom directly into its body. Choose the 3-way when you need simple two-branch changeover; choose the 5-way for more complex multi-branch routing.

2.   What does "3-Way" mean on a cryogenic ball valve?

A: "3-Way" means the valve has three connection ports and can switch flow among them. In the DQS15F, the ball is configured with a T-port or L-port passage pattern: the T-port connects a common inlet to either of two outlets (or connects the two outlets while isolating the inlet); the L-port shifts the flow from one outlet to the other with each 90° rotation. This lets a single three-way valve perform changeover, diversion, or isolation that would otherwise require two or more two-way valves. The 90° quarter-turn operation makes each switch fast and unambiguous, with the handle position giving visual confirmation of the active flow path.

3.  What are the typical applications of the DQS15F?

A: Typical applications include: flow changeover in cryogenic filling and vaporizing systems (e.g., directing LNG or liquid nitrogen to a selected tank or vaporizer); outlet selection on portable cryogenic tanks and dewars—using the three-way valve to route liquid or vapor as needed; cryogenic manifold flow routing, where one valve replaces multiple two-way valves; and transfer lines that need integrated overpressure protection, since the DQS15F's body carries safety-valve and rupture-disc ports for direct relief-device mounting. In short, any cryogenic system that needs to switch or divert flow between two branches, and protect that point against overpressure, under a single operator action—from −196°C to +85°C and up to 600 psig—is a fit for this valve.

4.   Why are there safety-valve ports and a rupture-disc port on the valve body?

A:  These ports let you mount overpressure-protection devices directly on the transfer line at the same point as the switching valve. The two threaded safety-valve ports on top accept spring-loaded safety valves, which vent pressure at a set point; the rupture-disc port at the bottom accepts a rupture disc, which bursts and vents the line if pressure rises faster than the relief valve can handle—or to the disc's burst pressure. This is valuable on portable tanks and transfer lines where mounting space is limited: instead of installing a separate tee with relief devices, the valve body itself provides the mounting points. It consolidates flow control and pressure protection into one compact, safe installation. (Relief devices are supplied/installed according to your system configuration; the manufacturer's specification applies.)

5.   What is an anti blow-out stem and why is it critical?

A: An anti blow-out stem is a stem whose shoulder is mechanically trapped inside the valve body, so internal pressure cannot push the stem out of the valve. In cryogenic service this is critical because the media is a liquefied gas under high pressure: a conventional stem held only by a gland can be ejected if the gland loosens under thermal cycling or vibration, releasing a violent jet of liquid that flashes to gas and can cause severe injury, equipment damage, and fire hazards. The DQS15F's stem is retained by design, guaranteeing the stem stays in place even if the packing is compromised. This is a fundamental safety requirement for pressurized cryogenic service.

6.    What does "full bore" mean and why does it matter for cryogenic transfer?

A: Full bore (full port) means the flow area through the ball and valve is equal to the nominal size of the connecting line—there is no reduced-diameter throat inside the valve. This matters for cryogenic transfer for three reasons: (1) low pressure drop—the fluid passes through with minimal resistance, preserving system pressure; (2) high flow rate—no bottleneck, so the maximum transfer rate is achieved; and (3) reduced flashing and turbulence—cryogenic liquids are near their boiling point, and throttling at a reduced port causes flashing (rapid vaporization) and pressure loss that reduce transfer efficiency. A full-bore diverter keeps the flow path clean and unrestricted, which is why it is preferred for high-flow LOX, LIN, and LNG transfer service.