Micro Switches for Extreme Cold & Vacuum
When a limit switch must operate at -184°C in liquid oxygen, maintain hermetic integrity under high vacuum, and survive repeated thermal cycling — standard industrial switches fail. Postek HK Series hermetically sealed micro switches are engineered and qualified for the most demanding cryogenic and vacuum applications.
Cryogenic & Vacuum Applications
❄️ Liquid Gas Handling
- LOX / LIN / LHe valve position sensing
- Cryogenic pump limit detection
- Dewar fill-level interlock
- Transfer line disconnect sensing
Why HK Series: Rated -184°C — verified for liquid oxygen service. Welded metal shell eliminates differential thermal contraction failures common in plastic-sealed switches.
🔮 Superconducting Systems
- Magnet quench detection circuits
- Cryostat vacuum integrity monitoring
- Current lead position sensing
- MRI / NMR system interlocks
Why HK Series: Non-magnetic options available. No organic materials that outgas under vacuum. SPDT configuration allows redundant monitoring of both N.O. and N.C. states.
🚀 Space Simulation
- Thermal vacuum chamber limit switches
- Cryo-panel positioning feedback
- Shroud deployment sensing
- Specimen manipulation interlocks
Why HK Series: Space Grade qualification available (YHYB S1201/001-2013). Radiation hardened to 100 Krad (Si). Hermetic seal survives repeated thermal cycling from -184°C to +260°C.
⚗️ Research Instruments
- Synchrotron beamline interlocks
- Neutron source sample changers
- Cryo-microtome limit detection
- Environmental test chamber monitoring
Why HK Series: 100,000 cycle mechanical life for high-frequency research use. Clean switching without particle generation. Compatible with extreme environments.
Cryogenic Performance
| Parameter | Specification | Relevance |
|---|---|---|
| Minimum Temperature | -184°C | Liquid oxygen / nitrogen service |
| Hermetic Seal | ≤ 1×10⁻³ Pa·cm³/s | Vacuum integrity maintained |
| Thermal Shock | Survives -184°C ↔ +260°C cycling | No seal failure from thermal stress |
| Leak Rate After Cycling | Unchanged | Proven by GJB 360B-2009 testing |
Recommended Models
| Model | Best For | Key Spec |
|---|---|---|
| HK-KWQM4-4Z-5-1E | Cryogenic + high temp cycling | 4A, -184°C to +260°C |
| HK-KWQM4-4Z | AC/DC cryogenic service | 5A, AC 400Hz capable |
| HK-KWQM4-4Z-9-1C | Low-current cryogenic circuits | 0.5A, -184°C to +121°C |
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Related: HK-KWQM4-4Z Product Page | Aerospace & mission-critical | Industrial Automation