Cryogenic Valves

Cryogenic Top Entry Ball Valve

Quick Specs Size: 2" - 12" (DN50 - DN300) Pressure: Class 150 - 300 / PN 10-40 Standard: API 6D, BS 6364, MSS SP-134, ASME B16.34 Body Materials: A351 CF8M, A182 F316, A351 CF8, Monel/K alloys Seat: PCTFE (Kel-F) / TFM soft seated; metal-to-metal with Stellite overlay available Design: Top entry, extended bonnet, ball vent hole Why This Valve Looks Nothing Like Your Standard Top Entry Walk into an LNG terminal and you'll see top entry ball valves on every major isolation point. Same bolted cover on top. Same internal access without pulling the valve off the line. But look closer—that stem is twice as long as it should be, there's a tiny hole drilled through the ball, and the seats are PCTFE, not PTFE. Three differences. Each one exists because cryogenic fluid at -196°C breaks things that work fine at ambient temperature. First: the extended bonnet. Standard packing—PTFE, graphite, whatever you chose—fails at -196°C. PTFE cracks under seating stress. Graphite loses resilience. The bonnet extension adds enough stem length that the packing chamber sits above the frost line, at roughly ambient temperature. Your packing works normally because it never sees the cryogenic zone. No special cryogenic packing material needed. No frozen glands. No leaks from packing that turned brittle overnight. Second: the ball vent hole. Close a standard ball valve in cryogenic service and liquid gets trapped inside the ball cavity. That liquid warms slowly through heat conduction from the body, expands as it shifts from liquid to gas, and the resulting pressure spike locks the ball against both seats. You can't turn it. The vent hole through the ball lets trapped fluid equalize pressure to the upstream side. Simple. Effective. Saves you from a locked ball that requires pipeline depressurization to free. Third: PCTFE seats, not PTFE. PTFE becomes brittle below -100°C—it cracks under seating stress at cryogenic temperatures. PCTFE (Kel-F) and TFM retain flexibility and sealing integrity down to -196°C. They hold their mechanical properties where PTFE gives up. When Top Entry Matters More Than Compactness Top entry access means you service the internals through the top cover without disconnecting the valve from the pipeline. In an LNG terminal, line isolation is costly and time-consuming. Draining a cryogenic line, warming it, depressurizing it, then pulling a valve off the line—that's days of work. Top entry lets your maintenance crew unbolt the cover, pull the ball and seats, inspect or replace, and bolt the cover back on. The valve stays in the line. The line stays drained but doesn't need warming for valve removal. Metal-to-metal seats with Stellite overlay are available for cyclic cryogenic service where the valve cycles frequently between open and closed. Soft seats handle most cryogenic isolation duty fine—ball valves in LNG terminals typically sit open or closed for long periods. But if your application cycles every few minutes, Stellite overlay on both seating surfaces survives the wear. Monel and K-alloy body materials are specified for extreme cryogenic where corrosion resistance beyond 316 stainless is required. Most LNG applications run CF8M or F316 and never look further. But if your process fluid contains aggressive components, or if you're operating below -196°C in helium or hydrogen service, the higher-alloy options matter. What Gets Missed in the Spec Review The vent hole direction matters. The hole should vent to the upstream side when the valve is closed—that's the side with lower pressure during isolation. If your system design requires venting to the downstream side instead, specify it. Don't assume. Bonnet extension length varies by installation. The extension needs to be long enough that the packing chamber stays above the frost line in your actual operating environment—not in a lab at -196°C with no wind, no ambient humidity, no thermal mass from adjacent piping. Cold climates with outdoor installations need longer extensions than climate-controlled indoor plants. Specify the ambient conditions, not just the fluid temperature. Body cover bolting on top entry valves takes more torque than you expect after cryogenic service. Stainless bolting at cryogenic temperatures grips differently. Use the manufacturer's torque values for reassembly after maintenance, not generic stainless torque charts. FAQ A: You can, but you shouldn't. PTFE starts losing flexibility well before it becomes fully brittle at -100°C. At -80°C, it's already stiffer than at ambient, and seating stress from cycle loading will accelerate cracking. PCTFE costs slightly more and gives you a wider margin. Use it. A: No. The vent hole is small—typically 3-6mm depending on ball size. It doesn't affect the pressure-containing boundary of the ball or the body. The hole is a pressure equalization path, not a structural weakness. A: Give the manufacturer your minimum ambient temperature and the installation orientation (vertical or horizontal stem). They calculate the frost line height on the stem based on thermal conductivity, ambient conditions, and fluid temperature. Outdoor installations in cold climates typically need 50-100mm more extension than indoor climate-controlled plants. A: You can, but the valve won't be compliant with BS 6364 or MSS SP-134, both of which require cavity pressure relief for cryogenic ball valves. Without the vent hole, you risk ball locking from trapped liquid expansion. It's a safety issue, not a preference. A: PCTFE (Kel-F) has higher mechanical strength at cryogenic temperatures—better for valves that see high seating loads or frequent cycling. TFM is a modified PTFE with improved cold-flow resistance and slightly better chemical compatibility. Both work at -196°C. For isolation duty, either is fine. For frequent cycling, PCTFE is the stronger choice.

Cryogenic Two-piece Ball Valve

Quick Specs Size: 1/2" - 4" (DN15 - DN100) Pressure: Class 150 - 300 / PN 10-40 Standard: API 6D, BS 6364, MSS SP-134, ASME B16.34 Body Materials: A182 F316 (forged), A351 CF8M (cast option) Seat: PCTFE / TFM soft seated; metal-to-metal available Design: Two-piece body, extended bonnet, ball vent hole Small Valve, Same Cryogenic Rules A two-piece cryogenic ball valve does the same job as a top entry—it isolates cryogenic flow at -196°C and seals reliably when closed. The extended bonnet keeps the packing warm. The ball vent hole prevents trapped liquid expansion. The PCTFE seats stay flexible where standard PTFE would crack. The difference is the body structure. Two-piece means the body splits into two halves—a main body and an end connector—joined by a bolted seam. The ball, seats, and stem load into the body cavity through the end connector opening, then the two halves bolt together. That makes the valve shorter and lighter than a top entry at the same size. No separate top cover. No extra bolting for the cover plate. The end connector doubles as the assembly access point. The tradeoff is straightforward: you can't service the internals without unbolting the body halves. That means removing the valve from the pipeline or disconnecting at least one end. Top entry lets you work through the top cover with the valve in the line. Two-piece doesn't. But for small sizes—1/2" through 4"—on LNG loading lines, cryogenic sampling points, and instrument isolation, compactness matters more than in-line serviceability. These valves sit in tight spaces where a top entry cover structure would add length you don't have room for. Where Two-piece Makes Sense LNG loading arm isolation. Small-bore cryogenic sampling lines. Instrument taps on cryogenic vessels. Pressure transmitter isolation on cryogenic storage tanks. These applications use valves in the 1/2" to 2" range, sometimes up to 4", and they're installed in congested piping layouts where every millimeter of valve length counts. A two-piece body at 1" is significantly shorter than a top entry at 1" because there's no cover assembly on top—just the extended bonnet and the actuator or handle. Forged body construction (A182 F316) is standard for two-piece cryogenic valves in the smaller sizes. Forged stainless has better impact resistance at cryogenic temperatures than cast—important for small valves that might see mechanical shock during LNG loading operations. Cast (CF8M) is available for 3" and 4" where forging cost becomes less favorable, but forged is the default for 1/2" through 2". The bolted seam between body and end connector uses a body gasket. At cryogenic temperatures, gaskets cold-flow under bolt relaxation—stainless bolts relax at -196°C, and the gasket material creeps under reduced bolt load. PCTFE body gaskets resist cold-flow better than standard PTFE gaskets, and spiral wound gaskets with stainless outer rings are specified for higher-pressure two-piece assemblies. The gasket material for the body seam is a design choice, not an afterthought. The Compactness Tradeoff Is Real If your maintenance plan includes in-line servicing—unbolt the cover, pull internals, reassemble without pipeline removal—two-piece can't do that. You unbolt the body seam, and the valve has to come off the line. For permanent installations on small-bore cryogenic lines where the valve stays in position for years and servicing means replacing the whole valve anyway, two-piece is the practical choice. If your application requires periodic internal inspection—regulatory-driven inspection intervals on LNG loading lines, for example—top entry at 2" and above gives you that access. Below 2", the size advantage of two-piece usually wins. FAQ A: Size and weight. A 1" top entry cryogenic ball valve is longer and heavier than a 1" two-piece because the top cover structure adds body height and bolting. In congested LNG piping layouts—loading arms, skid-mounted equipment, instrument manifolds—you often don't have room for the extra length. Two-piece fits where top entry doesn't. A: It's a potential leak path, same as any bolted joint in cryogenic service. Proper gasket selection—PCTFE or spiral wound with stainless rings—and correct bolt torque for the operating temperature mitigate the risk. The seam sees the same cryogenic temperature as the pipeline, unlike the packing gland which is isolated by the bonnet extension. Specify the right gasket material. Don't default to PTFE. A: Yes. pneumatic and electric actuators mount on the extended bonnet, same as top entry. The actuator stays at ambient temperature. The only difference is that actuator mounting on a two-piece body may have less structural support than on a top entry body—check the actuator weight against the manufacturer's bonnet mounting limits for your size and pressure class. A: PCTFE for Class 150 and 300 at -196°C. Spiral wound (stainless outer, graphite or PCTFE filler) for higher-pressure applications or where cyclic temperature loading is expected. PTFE body gaskets cold-flow at cryogenic temperatures under bolt relaxation—avoid them for cryogenic service. A: Yes. Same principle—trapped liquid in the ball cavity vents to the upstream side through the hole, preventing pressure lock. The vent hole design and direction are identical regardless of body style.

Cryogenic Butt Weld Globe Valve

Quick Specs Size: 1/2" - 2" (DN15 - DN50) Pressure: Class 150 - 800 / PN 10-130 Standard: BS 6364, MSS SP-134, ASME B16.34, ASME B16.11 Body Materials: A182 F316, A182 F304, Monel, A182 F55 (super duplex) Seat: Metal-to-metal; Stellite overlay available on disc and seat ring Design: Butt weld ends, extended bonnet, disc lifts off seat to open Zero Flanges, Zero Flange Leaks Every flanged joint in a cryogenic system is a liability. Gaskets cold-flow at -196°C—PTFE and compressed fiber gaskets creep under bolt load reduction as stainless bolts relax in cryogenic temperature. Bolt tension drops. The gasket creeps to fill the gap. The seal loosens. Cryogenic fluid finds the path. LNG leaks at -196°C are dangerous—they vaporize rapidly on contact with ambient air, creating flammable gas clouds in confined spaces—and expensive to fix because the line has to be drained, warmed, and depressurized before you can re-torque the flange bolts. Butt weld globe valves eliminate the flanged connection entirely. The valve welds directly into the pipeline. No gaskets. No bolts. No cold-flow risk. The weld joint is permanent—once it's in, it stays in. For small-bore cryogenic isolation on LNG loading arms, cryogenic sampling manifolds, and permanent instrument taps where the valve stays in position for years, that permanence is exactly what you want. You're not planning to remove these valves for maintenance. They're permanent isolation points on lines that get inspected, not dismantled. Why Globe, Why Not Ball Globe valves in cryogenic service throttle. Ball valves isolate. If you need to regulate cryogenic flow—reduce flow rate, modulate pressure, control filling rate on a cryogenic vessel—a globe valve's disc-and-seat design gives you progressive, controllable flow reduction across the full travel range. A ball valve gives you essentially binary flow—open or closed, with a narrow throttling range that erodes the seat quickly. Metal-to-metal seating is standard for cryogenic globe valves. The disc seats against a body seat ring, and both surfaces can take Stellite overlay for frequent cycling. Soft seats in a globe valve don't survive throttling service in cryogenic applications—the disc scrapes across the seat ring on every opening and closing cycle, and PCTFE wears faster under that linear scraping contact than it does under the rotational seating contact of a ball valve. Metal seats handle the wear. Stellite overlay extends the seat life for valves cycling dozens of times per day on cryogenic loading operations. Pressure classes go up to Class 800 on butt weld globe valves. That's PN130. Small-bore, high-pressure cryogenic isolation on high-pressure LNG storage vessels and cryogenic pump discharge lines—these applications need a valve that handles both cryogenic temperature and high pressure in a compact package. Butt weld construction with forged stainless body (A182 F316) gives you the pressure rating without flange connections that would leak at cryogenic temperature under high bolt load. The Weld Is the Commitment Butt welding means you can't remove the valve without cutting the weld. No flanges means no easy swap-out. If the valve needs replacement, you cut it out and weld a new one in. That's a permanent installation philosophy—you choose butt weld when you're confident the valve stays in service for the life of the piping system, and when eliminating flanged leak paths is worth the permanence tradeoff. On LNG loading arms and permanent instrument manifolds, that tradeoff is clear. The valve isolates a small-bore line that's part of a fixed installation. It doesn't get removed for routine maintenance—the line itself doesn't get dismantled. When the valve eventually needs replacement, it's a planned outage with weld cut-out and re-weld. Not convenient, but safe, because there were zero flanged leak paths for the entire service life. FAQ A: You can, but you're adding a flanged leak path on each end—two gaskets, two sets of bolts, two points where cold-flow and bolt relaxation create leak risk at -196°C. Butt weld eliminates both. If your piping system uses flanged connections throughout and you need valve removal capability, flanged ends are available. But if you're choosing this valve specifically for zero leak-path isolation, butt weld is the right end connection. A: Stellite is a cobalt-chromium alloy welded onto the seating surfaces—disc face and seat ring face. It's harder than the base stainless material and resists wear from repeated disc-to-seat contact during cycling. If your valve cycles more than a few times per day—cryogenic loading operations with frequent start/stop, sampling valves that open and close on each sample—Stellite overlay extends seat life significantly. For infrequent cycling (isolation valves that sit open or closed for weeks), standard metal-to-metal stainless seating is adequate. A: The practical size range is 1/2" through 2" because butt weld construction favors small-bore piping. Larger sizes—4" and above—use flanged connections because weld fit-up and inspection on larger bore welds is more complex, and the piping system typically has flanged joints at those sizes anyway. Small-bore permanent installations are where butt weld makes the most sense. A: Same principle. The stem extension puts the packing chamber above the frost line so the packing operates at ambient temperature. On a globe valve, the stem is thinner than a ball valve stem because it only carries disc lifting force, not ball rotational torque. The bonnet extension on a globe valve may be lighter construction than on a ball valve at the same pressure class, but the thermal function is identical—keep the packing warm. A: Yes—that's one of its primary applications. The disc-and-seat design gives you progressive flow control across the full travel range. For cryogenic filling rate regulation, pump discharge throttling, and pressure control on small-bore cryogenic lines, globe valves throttle effectively. If you need precise modulating control with an actuator, consider a cryogenic control valve instead—it has trim designed for continuous throttling.

Cryogenic Butterfly Valve with Inspection Port

Quick Specs Size: 2" - 12" (DN50 - DN300) Pressure: Class 150 - 300 / PN 10-40 Standard: BS 6364, MSS SP-134, API 609 Body Materials: A351 CF8M, A182 F316 (forged disc) Seat: PCTFE / TFM liner seat; triple eccentric metal seated with Stellite/Inconel overlay available Design: Double/triple eccentric disc, extended bonnet, body inspection port with sealed access One Valve, Two Functions Standard butterfly valves in cryogenic service do one thing—isolate flow. You close the disc, the line stops. Open it, the line runs. What's happening inside the body at that location? You don't know. To find out, you install a separate instrument tap upstream or downstream—a tee fitting with a temperature sensor, a pressure transmitter, maybe a sight glass for visual verification. Each tap is another connection, another potential leak point, another piece of piping to maintain in a system that's already running at -196°C where every additional fitting is a liability. This butterfly valve has an inspection port in the body. A sealed access point—bolted cover or glass window—that lets you visually inspect the disc position, insert a temperature probe into the flow path, or connect a pressure transmitter directly at the valve location. One valve body. One connection point. Isolation and process monitoring in the same installation. What the Inspection Port Actually Does Three capabilities, depending on the port configuration you specify: Visual inspection through a glass window. The disc position—open, closed, intermediate—is visible through the port without removing any covers. In LNG transfer lines, operators verify disc position before starting or stopping transfer operations. Visual confirmation at the valve is faster and more direct than relying on actuator position indicators that can drift or fail. Temperature sensing. Insert a temperature probe through the sealed port into the flow path. Cryogenic fluid conditions change rapidly during LNG loading and unloading—the fluid temperature at the valve location shifts as flow starts, stops, and stabilizes. Process safety depends on knowing what the fluid temperature is at critical isolation points. The inspection port gives you that data without a separate instrument manifold. Pressure monitoring. Connect a pressure transmitter to the port. Local pressure at the valve location—not upstream or downstream inferred pressure, but actual pressure at the isolation point—is critical for cryogenic transfer line safety. Pressure excursions during LNG loading can indicate line blockage, vessel overfill, or thermal expansion in dead-end sections. Real-time pressure at the valve catches those events. The Cryogenic Features Haven't Changed Extended bonnet—same as every other cryogenic valve in this catalog. The stem extension keeps the packing chamber at ambient temperature. PCTFE liner seat—same material logic as cryogenic ball valve seats, stays flexible at -196°C where PTFE becomes brittle. Ball vent hole equivalent—the disc design in a butterfly valve doesn't trap cavity liquid the way a ball valve does, but the body cavity behind the disc can accumulate cryogenic liquid when closed. The inspection port cover seals that cavity, and the body design includes pressure equalization to the upstream side. Triple eccentric metal seated version is available for high-cycling cryogenic applications—LNG transfer lines that cycle on every loading operation. The triple eccentric geometry means the disc lifts off the seat before rotating, reducing seating wear. Stellite or Inconel overlay on the disc and seat ring survives thousands of cycles at cryogenic temperature where soft liner seats would wear through. Specifying the Inspection Port Correctly The port size and location on the body vary by valve size. On smaller valves (2"-4"), the port is typically on one body side with a single bolted cover. On larger valves (6"-12"), you can specify dual ports—one on each side—for redundant sensing or combined temperature and pressure monitoring. The cover seal uses the same PCTFE gasket material as the body seam on two-piece valves—don't specify PTFE for the port cover gasket. Glass window material for visual inspection ports must withstand cryogenic temperature on the inner face and ambient temperature on the outer face simultaneously. Specify borosilicate glass or acrylic rated for thermal shock from -196°C to ambient. Standard window glass cracks under that thermal gradient. FAQ A: No. The port is designed into the body wall with adequate reinforcement—thicker body section at the port location, or external reinforcement pads on larger sizes. The port cover and gasket are rated to the same pressure class as the valve body. The port doesn't compromise the pressure boundary. A: Not directly. The port is designed for visual inspection and instrument insertion—temperature probes and pressure transmitters. Extracting a fluid sample through the port requires a separate sample extraction fitting that seals to the port cover. If you need sampling capability, specify it as part of the port configuration so the manufacturer provides the appropriate fitting and seal design. A: Yes. The butterfly valve body without the inspection port is a standard cryogenic butterfly valve with the same disc, seat, and bonnet design. You save the cost of the port machining, cover, and gasket. If your process monitoring is handled by separate instrument taps upstream and downstream, the inspection port is redundant and you can skip it. A: Triple eccentric metal seated handles high cycling—disc lifts off the seat before rotating, reducing wear per cycle. Stellite/Inconel overlay on seating surfaces survives thousands of cycles at -196°C. PCTFE liner seats are fine for isolation duty with infrequent cycling, but they wear through faster than metal seats on transfer lines that cycle on every LNG loading operation. If your valve cycles more than a few times daily, specify triple eccentric metal seated. A: Generally no. The port is machined into the body during manufacturing—body wall thickness at the port location is designed for the reinforcement. Retrofitting a port into a standard body would cut into a wall section that wasn't designed for an opening. If you need monitoring capability on an existing installation, install a separate instrument tee upstream or downstream of the valve.

Cryogenic Control Valve

Quick Specs Size: 1/2" - 8" (DN15 - DN200) Pressure: Class 150 - 600 / PN 10-100 Standard: BS 6364, MSS SP-134, IEC 60534, ISA 75 Body Materials: A351 CF8M, A182 F316, A182 F55, Monel Seat: Metal-to-metal with Stellite overlay Design: Globe-style body, extended bonnet, multi-stage or balanced trim available The Actuator Has to Stay Warm A control valve in cryogenic service has two problems that regular control valves don't face. First, the actuator. Pneumatic actuators use rubber diaphragms and elastomer seals. Electric actuators use motors, gear trains, and positioners with electronic components. None of these function at -196°C. Rubber diaphragms freeze solid—they crack when the actuator tries to stroke. Electric motors lose torque at cryogenic temperatures. Positioners drift or fail because their calibration assumes ambient operation. The extended bonnet on a cryogenic control valve does the same thermal isolation job as on isolation valves—keeps the packing chamber at ambient—but it has a second benefit specific to control valves: it puts enough distance between the cryogenic body and the actuator that the actuator operates at normal ambient temperature. The actuator mounting flange on the top of the extended bonnet is warm. The actuator works normally. No thermal shock. No frozen diaphragms. No positioner drift. Second: the trim. Control valves in cryogenic service throttle—they modulate flow continuously, not just open and close. That throttling creates pressure drops across the trim. In cryogenic pressure letdown—reducing LNG pressure from storage to transfer, for example—the pressure drop forces part of the cryogenic liquid to flash into gas instantly. Two-phase flow—liquid and gas mixed—erodes standard trim in months. The velocity is high, the density changes across the seat, and the flashing gas carries liquid droplets that impact the trim surfaces like sandblasting. Multi-stage Trim Stops the Flash Multi-stage trim splits the total pressure drop across several stages inside the valve body instead of dumping it all at one seat ring. Each stage reduces pressure incrementally. The flash intensity at each stage is lower because the pressure step is smaller. Two-phase flow is less aggressive because less of the liquid flashes at each step. The trim survives. Think of it this way: dropping 10 bar across a single orifice in cryogenic liquid service creates violent flash flow—most of the liquid flashes to gas at the orifice, and the resulting two-phase jet destroys the trim downstream. Dropping the same 10 bar across four stages—2.5 bar per stage—creates mild flash at each stage. The fluid at each intermediate pressure is still mostly liquid. The trim sees manageable flow conditions at every stage. The valve controls pressure without destroying itself. Balanced trim is available for high-pressure cryogenic regulation. Balanced means the plug has pressure equalization passages that reduce the net hydraulic force the actuator has to overcome. In high-pressure cryogenic service—say, regulating 50 bar LNG down to 5 bar—the unbalanced force on the plug would require an oversized actuator. Balanced trim cuts that force so a standard-size actuator handles the regulation without excessive air supply or motor power. Globe Body, Not Ball Cryogenic control valves use globe-style bodies, not ball bodies. Globe body geometry gives you the flow path shape that works for throttling—fluid enters the body, turns through the seat ring and plug, and exits with a controlled pressure drop. Ball valve geometry doesn't modulate well—the flow path is essentially a straight-through cylinder with a rotatable obstruction. You can throttle a ball valve slightly, but seat erosion is fast and the flow characteristic is non-linear. Cage-guided trim holds the plug centered in the cage during travel—better for high-flow applications where plug stability matters. Stem-guided trim guides the plug from the stem connection—simpler construction, adequate for smaller sizes and lower flow rates. Both are available with Stellite overlay on the seating surfaces. Stellite resists the erosive effect of two-phase cryogenic flow better than bare stainless, extending trim life in flash service. The Specification Details That Matter Trim material selection depends on your pressure drop and flash intensity. Stellite overlay on stainless trim handles moderate cryogenic flash—pressure drops below 5 bar per stage, flash ratio under 15%. Higher flash intensity requires harder trim materials—Inconel overlay, tungsten carbide inserts, or full Monel trim for severe service. Don't spec Stellite for everything. It costs more than bare stainless and if your application doesn't need it, you're wasting money. But if your application does need it and you spec bare stainless, you'll be replacing trim in six months. Bonnet extension length on control valves is usually longer than on isolation valves at the same size because the actuator mounting surface needs to be farther from the cryogenic body—the actuator mass creates a thermal conduction path through the bonnet, and the actuator itself needs a wider ambient temperature zone to function reliably. Specify the full installation condition: ambient temperature range, actuator type, and orientation. The manufacturer calculates the extension length from those inputs. FAQ A: You can, but it's expensive for isolation duty. A control valve body with trim and actuator costs more than a cryogenic ball valve or butterfly valve at the same size. If you only need open/close isolation, use an isolation valve. If you need flow modulation—throttling, pressure regulation, filling rate control—use a control valve. Don't overspecify. A: Unbalanced trim means the full process pressure acts on one side of the plug—the actuator has to overcome that hydraulic force to move the plug. Balanced trim has pressure equalization passages through the plug that cancel most of that force. The practical result: balanced trim lets you use a smaller actuator on high-pressure applications. If your inlet pressure is below 20 bar, unbalanced trim with a standard actuator is fine. Above 20 bar, balanced trim saves actuator size and air consumption. A: It depends on the flash ratio—the percentage of liquid that flashes to gas at the valve outlet. Low flash ratio (under 10%), one or two stages. Moderate flash (10-30%), three or four stages. High flash (over 30%), five or more stages with hardened trim material. The manufacturer calculates the flash ratio from your inlet pressure, outlet pressure, and fluid temperature. Provide those three values and let them specify the stage count. A: Physically yes, but the trim won't survive. Standard control valve trim—soft seats, stainless seating surfaces without overlay, single-stage pressure reduction—is designed for ambient and moderate-temperature service. Cryogenic flash flow destroys standard trim. A dedicated cryogenic control valve has trim designed for the erosive conditions of two-phase cryogenic flow—Stellite overlay, multi-stage pressure reduction, and metal-to-metal seating. You're buying the trim design, not just the bonnet extension. A: Pneumatic diaphragm actuators are the most common—simple, reliable, and the extended bonnet keeps them at ambient temperature. Electric actuators work but add cost and complexity; they also need the ambient temperature zone from the bonnet extension. Hydraulic actuators are used on very large sizes where pneumatic air supply is limited. All three mount on the extended bonnet. The actuator type doesn't change the valve body or trim design—it only changes the driving force for plug movement.

Cryogenic Flanged Forged Steel Gate Valve

Quick Specs Size: 1/2" - 2" (DN15 - DN50) Pressure: Class 150 - 800 / PN 10-130 Standard: BS 6364, MSS SP-134, ASME B16.34, ASME B16.11 Body Materials: A182 F316 (forged), A182 F304 (forged), A182 F51/F55 (duplex/super duplex forged) Seat: Metal-to-metal, solid wedge gate; Stellite overlay available Design: Forged body, socket weld or threaded ends, extended bonnet, rising stem OS&Y, solid wedge gate Small-Bore, Zero-Porosity Isolation This valve lives on the small lines. 1/2" through 2". The instrument taps. The sampling manifolds. The loading arm isolation points. The lines you don't think about until you need them—and then you need them to seal absolutely. At these sizes, forging isn't an upgrade over casting. Casting isn't cost-effective at 1/2"-2" anyway. Forging is the natural manufacturing process for small-bore valve bodies. And it gives you the zero-porosity guarantee that critical cryogenic isolation demands. A182 F316 forged body—no voids, no hidden leak paths, no microscopic porosity that could open at -196°C. If you're specifying a small-bore cryogenic gate valve and you care about body integrity, this is the one. It's not more expensive than a cast alternative. It's simply better because the manufacturing process that makes sense at these sizes also produces the body quality you need. Solid Wedge at Small Sizes—Keep It Simple The flexible wedge gate is important at 2" and above. At 1/2"-2", it's unnecessary. The contraction differential between the gate and the body is negligible at these small diameters. The gate is small. The body is small. They cool and contract nearly identically. A solid wedge gate seals fine without flexibility adjustment. Adding a flexible wedge mechanism to a 1/2" valve would add complexity without adding value. More parts. More potential failure points. More cost. No benefit. Solid wedge. Simple. Reliable. Seals at -196°C because the geometry is small enough that thermal contraction doesn't create a binding problem. This is engineering pragmatism—use the mechanism you need, skip the mechanism you don't. Socket Weld and Threaded—Standard for Small-Bore Socket weld ends for permanent installation. Threaded ends for maintenance-accessible connections. Butt weld available if you prefer it. These are the standard connection types for 1/2"-2" process lines in cryogenic service. Socket weld gives you a clean, permanent joint—no bolt-hole leak potential, no gasket to replace. You weld it once and it stays. For instrument isolation taps on air separation columns, for permanent cryogenic sampling points, socket weld is the right choice. Threaded ends give you the ability to remove and replace the valve without welding. For maintenance-accessible connections—where you might need to swap a valve during a turnaround without hot work—threaded ends save time. ASME B16.11 covers both. Class 800 at Small Diameters—Forged Bodies Handle It Pressure ratings go up to Class 800 at 1/2"-2" sizes. That's PN 130. Forged bodies handle high pressure efficiently at small diameters—the material is dense, uniform, and the wall thickness relative to bore diameter is substantial. This is useful for high-pressure cryogenic service. Not every cryogenic line runs at Class 150. Hydrogen liquefaction, high-pressure gas processing, certain air separation stages—these services run at elevated pressure. The forged body at small bore gives you the pressure rating without going to a specialized high-pressure valve design. Where This Valve Sits LNG loading arm isolation. Cryogenic sampling manifold taps. Instrument isolation on air separation columns. Small-bore shutoff on ethylene cracking units. Any point where you need a gate valve at 1/2"-2" with forged-body integrity and cryogenic-rated design. It's not the glamorous valve on the project. It's the one that sits on the small lines nobody photographs. But those lines matter—instrument feeds, sampling access, safety isolation. When they fail, you notice. FAQ A: At 1/2"-2", the contraction differential between gate and body is negligible—they cool and contract nearly identically. A solid wedge seals reliably without the flexibility mechanism. Adding flexible wedge would increase complexity and cost without any performance benefit at these small diameters. A: Socket weld for permanent installations—clean joint, no gasket, no leak potential beyond the weld itself. Threaded for maintenance-accessible connections where you might need to swap the valve during a turnaround without hot work. Choose based on your maintenance access philosophy. A: Forged bodies handle high pressure efficiently at small diameters. The material is dense and uniform (no porosity), and wall thickness relative to bore diameter is substantial. At 1/2"-2", the forged A182 F316 body supports Class 800 without requiring a specialized high-pressure valve design. A: Yes. Stellite overlay is available for high-cycling applications where seat wear is a concern. For standard isolation service with infrequent operation, bare metal-to-metal seating is sufficient. For valves that cycle regularly—sampling manifold taps, frequent isolation points—Stellite extends seat life. A: Duplex and super duplex forged bodies provide higher mechanical strength and improved corrosion resistance compared to standard 316. Useful for cryogenic services with corrosive media or where weight reduction through higher allowable stress is a design objective. Not standard for clean LNG service but available for demanding applications.

Cryogenicl Gate Valve

Quick Specs Size: 1/2" - 24" (DN15 - DN600) Pressure: Class 150 - 600 / PN 10-100 Standard: API 6D, BS 6364, MSS SP-134, ASME B16.34 Body Materials: A351 CF8M (cast 316), A351 CF8 (cast 304), A216 WCB (cast carbon steel, -46°C min) Seat: Metal-to-metal, flexible wedge or solid wedge gate Design: Cast body, flanged or butt weld ends, extended bonnet, rising stem (OS&Y) or non-rising stem, body cavity vent The Valve That Covers Everything This is the baseline cryogenic gate valve. The one that shows up on every LNG plant spec sheet. The one that handles 1/2" through 24" in a single design. It's not specialized. It's not the forged-body premium version. It's not the compact two-piece option. It's the general-purpose isolation valve that works at every cryogenic temperature from -46°C down to -196°C. And that breadth is its strength. When you're specifying valves for an entire cryogenic process line—LNG processing, air separation, ethylene cracking—you need one valve type that covers the range. You don't want three different gate valve designs for three different size ranges. You want one. This is that one. Cast Body—Practical at Size Let's talk about the cast body honestly. A351 CF8M at -196°C. A216 WCB at -46°C. Cast, not forged. Forged bodies are better—no porosity, no hidden voids, no potential leak paths. We make forged versions. But at sizes above 12", forged bodies cost two to three times what cast bodies cost. The forging process at large diameters is expensive. Cast is cost-effective. And for most applications—not the critical isolation points, not the safety shutdowns, but the standard process isolation on a cryogenic line—cast A351 CF8M works. It holds. It seals. BS 6364 cryogenic testing confirms it. You specify forged for the critical points. You specify cast for the rest. That's how real plants are built. Flexible Wedge for Deep Cold, Solid Wedge for Moderate At -196°C, the gate and body contract differently. Different sections cool at different rates. A solid wedge gate can bind. The flexible wedge—two discs with a center ball—adjusts independently against each seat ring. Seating stays tight. Opening stays manageable. At moderate cryogenic temperatures—-46°C to -100°C—the contraction differential is smaller. A solid wedge gate seals fine. It's simpler. It's cheaper. It's more reliable because there's less mechanism to maintain. For air separation plant isolation at -100°C, solid wedge is the practical choice. We offer both. You pick based on your operating temperature. The Body Cavity Vent—Trapped Gas Kills Valves Cryogenic gate valves have a vent hole on the body cavity. Here's why. When the valve closes, liquid cryogenic media fills the body cavity around the gate. As the surrounding temperature fluctuates, that liquid can evaporate. Gas pressure builds inside the cavity. The gate gets locked—pressure on both sides of the wedge, no way to open it without equalizing first. The vent hole lets that gas escape. Pressure equalizes. The gate moves freely. It's a small detail. But without it, the valve fails in service—not because the materials are wrong, not because the design is bad, but because trapped gas pressure locks the mechanism. BS 6364 requires it. We put it on every valve we build. Extended Bonnet—Same Principle, Any Size The packing gland needs to stay warm. At -196°C, packing freezes. The stem seizes. You can't operate the valve. The extended bonnet lifts the packing away from the cold zone—30°C ambient at the gland, -196°C at the body. Every cryogenic valve needs this. This one has it. From 1/2" to 24". Same principle. Same reliability. FAQ A: At sizes above 12", forged bodies cost 2-3x more than cast. For standard process isolation—not critical safety shutdowns—cast A351 CF8M is cost-effective and performs reliably. BS 6364 cryogenic testing validates cast body performance. You reserve forged bodies for the critical points and use cast for the rest. A: Flexible wedge for deep cryogenic service at -196°C where differential thermal contraction can bind a solid gate. Solid wedge for moderate cryogenic temperatures (-46°C to -100°C) where contraction differential is small enough that a solid wedge seals reliably without the flexibility mechanism. A: When the valve closes, liquid in the body cavity can evaporate and build gas pressure, locking the gate between two pressure forces. The vent hole lets gas escape so the gate can move freely. BS 6364 requires this feature on all cryogenic gate valves. A: Class 150 through Class 600 (PN 10-100). The cast body and metal-to-metal seat design handle the full range. At higher pressures, consider the forged steel version for zero-porosity body integrity. A: Rising stem (OS&Y) gives visible position indication—you can see if the valve is open or closed by looking at the stem. Critical for isolation verification before maintenance or hot work. Non-rising stem saves vertical space in tight installations but requires a separate position indicator.

Cryogenic Forged Steel Gate Valve

Cryogenic Flanged Globe Valve