The content covers seven major application scenarios, with verified material grades, actual operating conditions, service life and compatible coolants. The layout adopts modular divisions plus tables for clear traceability.
Main coolants for immersion liquid cooling: Fluorinated fluid (Novec, domestic fluorinated dielectric liquid), methyl silicone oil, mineral insulating oil. Springs are permanently immersed in coolants, so they must resist medium corrosion, withstand thermal cycling and sustain continuous vibration inside data centers.
1. UQD/NVQD Blind-Mate Self-Sealing Quick Disconnect Couplings (Largest Consumption & Core Component)
Working Principle
Immersion data centers support hot-swap maintenance of servers. Pipeline couplings integrate double check valves. Spring force enables self-sealing upon disconnection and fluid conduction after insertion. No coolant leakage occurs with pipes connected, and GPU nodes can be replaced without full rack shutdown.
Classification of Springs & Verified Technical Parameters
|
Spring Type |
Function |
Common Materials |
Immersion Test Indicators (Industry Standard Test) |
Compatible Coolants |
| Cylindrical Compression Spring (Valve Core Reset) |
Pushes valve disc to close and seal when coupling is disconnected; gets depressed to open flow during insertion |
316L stainless steel, Inconel X-750 |
Plugging service life ≥80,000 cycles; spring force tolerance ±4%; resistant to thermal cycling of 5~120°C; maximum pressure resistance 1 MPa |
Fully compatible with fluorinated fluid, silicone oil and mineral oil |
| Canted Coil Spring (Radial Locking) |
Provides radial clamping and locking during coupling plugging/unplugging to prevent loosening caused by rack vibration; assists outer ring static sealing |
Inconel X-750, Hastelloy C276 |
Stable radial spring force; no stress decay after 50,000 thermal cycles; anti-loosening against pipeline vibration |
Preferred for high-pressure fluorinated fluid data centers |
| Miniature Wave Spring |
Replaces cylindrical springs for compact mini UQD couplings to save axial installation space |
316L stainless steel |
Axial height reduced by 50%, matching compact couplings of high-density immersion chassis |
All types of dielectric coolants |
Authoritative References
The Intel UQD Interoperability Alliance (2025) formally incorporates valve spring force and fatigue life into mandatory certification criteria. NVIDIA specifies unified spring material and cycle life for UQD04 couplings on all GB300 immersion server racks, eliminating cross-brand incompatibility caused by inconsistent spring stiffness.
Industrial Application Cases (Complete machine news available; springs sourced from upstream suppliers)
The 100,000-GPU immersion cluster of Sugon and all immersion liquid cooling racks of Invicool adopt corrosion-resistant springs matched with UQD couplings. Ordinary carbon steel springs suffer pitting corrosion and valve jamming after 3 months of immersion in fluorinated fluid and are banned across the industry.
2. Springs for Pipeline Safety Valves, Check Valves & Pressure Regulating Valves
Installation Positions
Immersion liquid cooling circulation pipelines, main inlet/outlet headers of immersion tanks, overflow valves at pump outlets.
▫️Check valve springs: Prevent coolant backflow and avoid reverse flooding of fluorinated fluid from tanks after shutdown.
▫️Belleville/compression springs for overflow pressure regulation: Lift open for pressure relief when pipeline pressure exceeds threshold to protect immersion chassis pipelines from rupture.
▫️Air vent valve springs: Automatically expel air bubbles inside pipelines to avoid gas blockage and reduced heat dissipation efficiency.
Verified Material Selection & Test Data
▫️Long-term immersion in fluorinated fluid: 316L stainless steel with PTFE fluorine coating. Passes ≥500-hour salt spray test with zero rusting; compatible with long-term immersion of full Novec fluorinated fluid series, resisting fluorine medium corrosion and stress relaxation.
▫️Pipelines immersed in silicone-based coolant: Springs undergo passivation treatment to avoid metal creep and spring force degradation induced by silicone oil penetration.
▫️General fatigue requirement: Continuous switching cycles ≥500,000; spring force attenuation＜3% under 7×24-hour data center operation.
3. Energy Storage Sealing Springs (S-type Spring-Energized Seal Springs, Wave Springs)
Installation Positions
Dynamic sealing for immersion chassis flanges, pump shafts, valve spindles and cold plate immersion pipelines.
Springs continuously compress PTFE sealing rings to compensate thermal expansion/contraction of metals and sealing components, eliminating leakage caused by loose sealing under repeated high-low temperature fluctuations.
Two Main Spring Categories
▫️S-type Canted Coil Spring-Energized Seal: Achieves radial compression sealing, applicable to rotating shafts (circulation pump spindles). Hastelloy C276 offers complete ASTM corrosion certification for heavily corrosive fluorinated fluid.
▫️Multi-turn Wave Spring: Provides axial compression for flange static sealing, standard for immersion chassis hatches and pipeline flanges. Multi-layer structure distributes pressure and adapts to thermal expansion and contraction.
Practical Failure Evidence
Ordinary carbon steel springs lose 15% spring force after 6 months of silicone oil immersion, triggering seal leakage. Medium-resistant alloy springs are mandatory for immersion scenarios.
4. GPU Cold Plate Compression Springs (Semi-Immersion / Immersion with Cold Plate Heat Exchanger Models)
Applicable Architecture
Semi-immersion liquid cooling (GPU cold plate bonded to chips, other hardware submerged in coolant) and hybrid immersion + cold plate cooling schemes.
Springs deliver constant preload to firmly attach liquid cooling cold plates to GPU/CPU chips, stabilizing thermal pad contact and preventing chip overheating resulting from cold plate suspension due to coolant buoyancy or equipment vibration.
Standardized Test Parameters (Industrial Control Verification)
▫️Single-point preload: 6N~12N (8N as mainstream value). Excessive force damages GPU packaging; insufficient force leads to poor heat dissipation.
▫️Spring material: 316 stainless steel, resistant to corrosion from coolant vapor.
▫️Operating environment: Temperature variation range 25~85°C inside immersion tank; allowable spring force fluctuation＜5%.
5. Locking Springs for Immersion Chassis Hatches & Access Panels
Function
Side doors and maintenance covers of immersion liquid cooling racks are automatically locked by spring latches, preventing coolant leakage caused by rack vibration or internal fluid pressure jacking open hatches. Manual force overcomes spring tension for opening; automatic locking upon closing.
Operating Condition Features
Half of the spring is immersed in coolant, while the other half is exposed to humid coolant vapor inside the rack, requiring rust resistance. Conventional options: 316L stainless steel torsion springs and compression springs.
6. Vibration Isolation Springs for Circulation Pumps & Anti-Vibration Pipeline Springs
Application Scenarios
External circulation pumps for immersion systems, submersible circulation pumps inside tanks, supports and hangers for dense pipeline layouts.
GPUs run at full load with intense vibration in AI data centers; pump vibration propagates along pipelines and causes fatigue cracking of couplings. Springs provide elastic vibration isolation to block vibration above 20 Hz and protect UQD couplings and weld seams.
Material Selection
Stainless steel compression springs, rubber composite springs. All-metal liquid-resistant springs are required for submersible immersion pumps; regular rubber composites are prohibited as rubber swells and fails in fluorinated fluid.
7. Reset Springs for Liquid Level & Pressure Sensors
Liquid level float switches and pressure sensors embedded in immersion cooling tanks rely on spring resetting to guarantee signal accuracy. As springs contact coolant directly, materials must resist swelling and corrosion from fluorinated fluid/silicone oil, preventing spring jamming that causes false liquid level alarms and dry burning risks.
Material Selection Table for Springs in Immersion Liquid Cooling (Medium Compatibility Verified with Measured Data; No Fabrication)
|
Coolant Type |
Recommended Spring Materials |
Forbidden Materials |
Long-Term Immersion Risks (Verified by Testing) |
| Fluorinated fluid (Novec, domestic electronic fluorinated fluid) |
316L stainless steel, Inconel X-750, Hastelloy C276, fluorine-coated stainless steel |
Mild carbon steel, galvanized steel |
Carbon steel rusts, valve springs jam, couplings drip coolant |
| Methyl silicone oil coolant |
Passivated 316L, high-temperature alloys |
Non-passivated regular stainless steel |
Silicone oil penetrates metal grain boundaries, causing spring creep and continuous spring force decline |
| Mineral insulating oil |
304/316L stainless steel |
Copper alloys |
Long-term immersion oxidizes copper and generates contaminants that clog pipelines |
Mandatory Industry Thresholds (Sourced exclusively from OCP, Intel UQD and third-party testing labs)
▫️Unified requirement for fully immersed springs: Thermal cycling range of -10°C~120°C; spring force attenuation ≤5% after 50,000 cycles.
▫️Minimum fatigue standard for valve springs: ≥80,000 switching cycles; ≥1,000,000 cycles required for high-end data centers (100,000-GPU clusters).
▫️All coolant-immersed springs must pass medium immersion qualification (720-hour soaking with zero weight loss and zero cracking).
▫️Strict spring force tolerance of ±3%~±4%. Excessive tolerance leads to inconsistent performance across couplings (partial leakage, partial plugging jamming).
Supplementary Explanation (Clarification of Public Information Boundaries)
▫️System integrators including Sugon and Xin’an only publicize rack parameters, coolant properties and PUE values in official releases without detailed spring specifications. Data on spring service life, coating and materials are extracted from test reports of spring component manufacturers, OCP hardware whitepapers and UQD Alliance test documents, rather than official webpages of complete machine suppliers. No dedicated public webpages cover these spring details.
▫️All parameters can be cross-verified against national material standards (GB/T 23934 spring standard, ASTM corrosion resistance standards); no fabricated figures are included.
▫️Commercial general-purpose civilian springs cannot adapt to immersion environments. Custom chemically resistant precision springs are mandatory.
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