Cryogenic pressure transducer for low temperature pressure measurement. -196℃～+125℃, -260℃/-350℃ (special models).
The Cryogenic pressure transducer adopts a stainless-steel integrated packaging structure, with the pressure-sensitive diaphragm welded directly to the transmitter housing. This makes the unit compact, vibration-resistant and suitable for liquid nitrogen, liquid oxygen, liquid argon, LNG, and liquid hydrogen tanks. Sino-Inst supplies models for –196℃ standard service and –260℃ ultra-low temperature special applications, with 4–20 mA / HART output and ATEX / IECEx certification options for hazardous-area service.
Sino-Inst offers a variety of low pressure transducers for industrial pressure measurement. If you have any questions, please contact our sales engineers.
Description
The Cryogenic pressure sensor adopts a stainless-steel integrated packaging structure, where the pressure-sensitive diaphragm and the transmitter circuit are sealed together. The cryogenic-rated diaphragm is direct-welded to the housing, eliminating the soft-seal failure modes that occur at LN2 / LH2 temperatures.
Its advantages are small size, high measurement accuracy, and a high dynamic-response frequency. The transducer keeps zero-shift under ±0.5 % FS through a full thermal cycle to liquid nitrogen, and is suitable for cryogenic-fuel test stands, MRI helium dewars, semiconductor LN2 / LAr lines, and LNG bunkering racks.
Features of Cryogenic Pressure Transducer
- Cryogenic-rated wetted diaphragm: 316L stainless, Monel 400 (LOX), Inconel 625 (LH2).
- Operating range −196 ℃ to +125 ℃ standard; −260 ℃ / −350 ℃ in special configurations.
- Accuracy ±0.075 % FS (capacitive remote seal) to ±0.5 % FS (sputtered thin-film).
- Direct-weld diaphragm — no soft seals, no fill-fluid freeze risk.
- Output: 4–20 mA / HART, 0.5–4.5 V ratiometric, RS-485 Modbus RTU.
- Hazardous-area certification: ATEX II 1 G Ex ia IIC T6 Ga (LH2), IIB+H2 (LNG), IECEx, EC79.
- Oxygen-clean variant: EIGA Doc 33 / BAM autoignition test pass for LOX service.
- Process connection: 1/4" NPT, 1/2" NPT, G1/2 BSP, M20×1.5, flange DN25–DN100.
Specifications of Cryogenic Pressure Transducer
| Parameter | Standard | Cryogenic / Ultra-low |
|---|---|---|
| Operating temperature | −196 ℃ ~ +125 ℃ | −260 ℃ / −350 ℃ (special) |
| Pressure ranges | 0–10 / 35 / 100 bar | 0–350 / 700 bar |
| Accuracy | ±0.25 % FS (sputtered thin-film) | ±0.075 % FS (capacitive remote seal) |
| Output | 4–20 mA / 0.5–4.5 V | 4–20 mA + HART, RS-485 |
| Wetted material | 316L SS | Monel 400 (LOX), Inconel 625 (LH2) |
| Hazardous-area certification | — | ATEX Ex ia IIC T6 Ga / Ex d IIB+H2 / IECEx / EC79 |
| Oxygen-clean option | — | EIGA Doc 33 / BAM autoignition pass |
| Power supply | 10–32 VDC | 10–32 VDC, loop-powered |
| Protection rating | IP65 | IP67 |
Read more about: Common Units Of Pressure
Applications of Cryogenic pressure transducer
- LNG plants and bunkering — saturation pressure on liquefaction trains, ship-to-shore transfer.
- Liquid-oxygen production — air-separation columns, on-site bulk storage, cylinder filling. Oxygen-clean variant required.
- Liquid-hydrogen fueling — dispenser nozzle, on-site storage, mobile bunkering. ATEX IIC + EC79.
- Industrial gas (LN2 / LAr) bulk storage — vacuum-insulated tanks, dewar trucks, MRI helium dewars.
- Aerospace propellant test stands — cryogenic-fuel feed, LH2 / LOX run tanks.
- Cryogenic biology and superconducting magnets — LN2 phase storage, NMR / MRI service.
What is a Cryogenic Pressure Transducer?
A cryogenic pressure transducer measures pressure in fluids below −150 ℃. The wetted diaphragm sits in liquid nitrogen, oxygen, argon, LNG, or liquid hydrogen, while the electronics stay at near-ambient via a remote diaphragm seal or thermal-break standoff.
The unit must keep zero, span, and accuracy across a 200–250 K temperature delta. A standard pressure transmitter installed on a LN2 line freezes the fill fluid in the diaphragm and produces a permanent zero shift; a cryogenic-rated unit uses cold-bath calibration, halocarbon fill (LOX) or thermal-break mounting to survive the cold-side environment.
How does the Cryogenic Pressure Transducer work?
Three sensing-element technologies dominate cryogenic pressure transducers: sputtered thin-film deposited directly on a stainless diaphragm (good for direct LN2 immersion), piezoresistive silicon with a capillary remote seal (LOX / LNG plant service), and capacitive (oil-filled) for high-accuracy custody-transfer service.
The pressure-sensitive element converts the applied force into a tiny resistance or capacitance change, the conditioning circuit linearizes and temperature-compensates the signal, and the output stage drives a 4–20 mA / HART loop or 0.5–4.5 V ratiometric output. For LH2 service the output curve is fitted across multiple thermal points (+25 ℃ → 0 ℃ → −80 ℃ → −196 ℃ → −253 ℃) to keep the in-service error band under ±0.5 % FS.
Q&A
What is the temperature range of a cryogenic pressure transducer?
Standard models cover -196 ℃ to +125 ℃. Special configurations are rated to -260 ℃ for liquid hydrogen and ultra-low temperature aerospace service. The wetted diaphragm sits at the cryogen temperature; the electronics stay near ambient via remote seal or thermal-break standoff.
Do I need an oxygen-clean variant for LOX service?
Yes. Liquid oxygen ignites organics. Wetted parts must be precision-cleaned to EIGA Doc 33 / BAM standards, the seal fluid must be halocarbon (not silicone), and O-rings must be Viton or PCTFE. A standard LN2 transducer fails BAM autoignition testing and is unsafe in LOX service.
What ATEX rating do I need for liquid hydrogen?
Gas group IIC, temperature class T1, Zone 0 or Zone 1. Marking II 1 G Ex ia IIC T6 Ga (intrinsically safe) is the typical requirement for LH2 tanks and fueling nozzles. Mobile applications additionally need EC79 type approval.
Can I use a regular pressure transmitter on a LN2 tank?
Only on the warm vapor-phase side. A standard transmitter mounted on the cold liquid line freezes the fill fluid in the diaphragm and produces a permanent zero shift. Either spec a cryogenic unit, add a remote-seal capillary, or tap above the liquid level.
How much zero drift should I expect after the first cool-down?
0.3-0.8 % of full scale is typical for sputtered thin-film and piezoresistive elements after the first thermal cycle to LN2. Bench-zero the transmitter, install it, cool down, and re-zero in service before commissioning.
SMT3151 Diaphragm Seal
Capillary remote-seal transmitter for LN2 / LOX / LNG plant service. ±0.075 % FS, 316L diaphragm, halocarbon fill option for oxygen-clean lines.
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Compact transducer for HVAC and refrigeration cold service down to −40 °C. Compatible with R134a, R410A, ammonia loops.
Sino-Inst supplies cryogenic pressure transducers globally — LN2, LOX, LAr, LNG, and LH2 service.
Pressure ranges from 0–10 bar through 0–700 bar. ATEX / IECEx / EC79 certification options for hazardous-area service. Oxygen-clean variant per EIGA Doc 33 for LOX. HART 7 communication for asset-management integration.
Sino-Inst is a Chinese manufacturer with a global distribution network. Cryogenic transducers are most popular in North America, Europe, India, Southeast Asia, and the Middle East. Send your specification — cryogen type, pressure range, hazardous-area zone, process connection — and our engineering team will quote within 24 hours.
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Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Cryogenic Pressure Transducer for LN2/LOX/LH2 | Sino-Inst
Cryogenic pressure transducer for low temperature pressure measurement: -196℃ to +125℃, special models down to -260℃. ATEX option for LH2/LNG, oxygen-clean for LOX.
Product SKU: Cryogenic Pressure Transducers
Product Brand: Sino-Inst
Product Currency: USD
Product Price: 500
Price Valid Until: 2099-09-09
Product In-Stock: InStock
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