DJ06/10S Cryogenic Extended Globe Valves

The DJ06/10S series cryogenic extended globe valves are designed for cryogenic tanks and mini-bulk storage tanks as trycock, hose drain, liquid fill, or vent valves. They are equally suited for LNG fueling stations, portable liquid oxygen tanks, and other cold-gas applications requiring extended-stem thermal isolation. All models feature a union bonnet structure, one-piece stainless steel stem with spring-washer-loaded packing, and a PCTFE soft-seal conical seat to prevent galling from over-torquing. Every valve is 100% factory tested, cleaned, and degreased for liquid oxygen service per CGA G-4.1. Compliant with TSG 23 and GB/T 34530.2.

| Working Principle

The DJ06/10S is a straight-pattern manual globe valve that uses a rising stem + conical soft-seat design for cryogenic on-off control. The extended brazed tube thermally isolates the handwheel end from the cold valve body, forming a gas-column insulator that prevents frost build-up and stem seizure at the packing.

Opening: Turn handwheel counterclockwise → stem rises via threaded drive → PCTFE seal lifts off the conical seat → fluid flows from inlet through seat bore into outlet. Flow rate is proportional to stem lift.

Closing: Turn handwheel clockwise → stem descends → PCTFE seal compresses against the conical seat, elastically deforming to conform to the seating surface → flow is fully shut off. The conical seat geometry prevents seat galling from over-torquing.

Thermal Isolation: The stem runs inside a long stainless steel brazed tube; ambient air plus the tube air gap create a natural thermal barrier. Cold vapor generated in the valve cavity lingers in the lower section of the extended stem, while the upper section remains at ambient temperature, protecting the PTFE packing from freezing and preventing stem seizure.

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 Factory Shoot

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 Application Video

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 Product parameters

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Comment & FAQ

1:  What is the difference between DJ06/10S and the standard DJ10 series?

A: The DJ06/10S is an extended-stem model — the stem is significantly elongated via a stainless steel brazed tube, keeping the handwheel far from the cold valve body. The standard DJ10 is a short-stem compact design. The extended stem's core function is thermal isolation — it keeps the packing zone at ambient temperature, preventing ice-induced stem seizure or packing leakage. Application also differs: DJ06/10S is primarily for tank-mounted interfaces (trycock/drain/fill/vent), while DJ10 targets Dewar cylinders.

2. Why PCTFE for the seat seal and not PTFE?

A: PCTFE (polychlorotrifluoroethylene) retains elasticity at −196°C without significant cold flow deformation, whereas standard PTFE undergoes cold flow creep under cryogenic high-pressure, leading to seal failure. Hence PCTFE is the preferred seat material for cryogenic valves. PTFE is used for packing because the extended stem keeps that zone at ambient temperature, where PTFE performs adequately and costs less.

3. What media can this valve handle?

A: What special requirements apply to oxygen service? Compatible media include LOX, LIN, LAR, LNG, LCO₂, LC₂H₄, etc. For oxygen service, the valve is factory-cleaned and degreased per CGA G-4.1 — use straight from the package; do not expose to any grease or oil. Wear clean gloves during installation and ensure the piping and fittings are equally clean.

4. What does the union bonnet structure mean for field maintenance?

A: The union bonnet allows the stem, sealing element, and packing assembly to be removed for replacement or cleaning by simply unscrewing the bonnet nut — without cutting the piping or removing the entire valve body from the tank. For valves welded onto tanks, this design avoids destructive disassembly, dramatically reducing maintenance cost and downtime.