Nexisense Ultrasonic Oxygen Sensor: High-Precision O₂ Concentration Monitoring Solutions for Medical Oxygen Concentrators and Respiratory Therapy

Technical Principle and Medical-Grade Advantages of Ultrasonic Oxygen Sensors

Ultrasonic oxygen sensors are based on the transit-time difference method, utilizing the difference in propagation speed of ultrasonic waves in gases with different oxygen-nitrogen mixing ratios to measure concentration. Oxygen (molecular weight 32) and nitrogen (molecular weight 28) have significant differences in sound velocity. The sensor uses a pair of ultrasonic transducers to alternately transmit and receive pulses, precisely measuring the downstream and upstream propagation time difference Δt, and calculates oxygen concentration combined with temperature compensation.

Core Characteristics of Nexisense US1000/US1010 Series:

• Range: 0–100%vol O₂ (extendable to 0–125%)

• Accuracy: ±1.5% FS (typical ±0.5% FS @ 21% O₂)

• Resolution: 0.1%vol

• Response Time (T90): ≤1.5 s

• Zero Drift: Annual drift <±0.5%vol (no periodic calibration required)

• Operating Temperature: 0–50°C (compensation range -10～60°C)

• Power Consumption: Standby<30 mW, typical <80 mW

• Output: UART (TTL 3.3V/5V), I²C, analog 0–5 V / 4–20 mA optional

• Lifespan: ≥10 years (continuous operation, MTBF >200,000 h)

Compared with electrochemical oxygen sensors, the ultrasonic solution has no oxygen consumption, no poisoning risk, no moving parts, and strong resistance to cross-interference from CO₂, N₂O, and anesthetics. Compared with paramagnetic oxygen sensors, it is smaller in size, faster in response, lower in power consumption, and more cost-effective, particularly suitable for real-time outlet concentration monitoring in medical oxygen concentrators and closed-loop oxygen concentration control in ventilators.

Core Application Scenarios in Medical Oxygen Concentrators and Respiratory Therapy

Home/Medical Oxygen Concentrator Outlet Concentration Monitoring
Nexisense sensors are integrated into the outlet gas path of PSA oxygen concentrators to achieve continuous measurement of 0–95%vol O₂. UART/I²C digital output directly connects to the main control MCU, supporting concentration-flow linkage closed-loop regulation to ensure outlet oxygen concentration stability within 93±3%. In actual projects, they have been mass-applied to multiple leading domestic oxygen concentrator brands, with average fault-free operation exceeding 4.5 years, significantly reducing after-sales calibration and maintenance costs.

High-Flow Nasal Cannula Oxygen Therapy (HFNC) and Ventilator Oxygen Concentration Control
Deployed at the front end of the air-oxygen mixing gas path in ventilators/high-flow oxygen therapy equipment, providing real-time O₂ concentration feedback to the proportional valve controller for concentration closed-loop. Response time<1.5 s supports rapid FiO₂ adjustment, combined with flow sensors for precise oxygen delivery. In a respiratory ICU project at a tertiary hospital, the Nexisense module controlled oxygen concentration fluctuations within ±1.5%, effectively reducing the risk of oxygen toxicity and hypoxemia in ARDS patients.

Anesthesia Machine and Operating Room Gas Monitoring
Integrated into the fresh gas path or circuit of anesthesia machines to monitor inspired oxygen concentration (FiO₂) and expired oxygen concentration (FeO₂), supporting multi-gas ratio control of N₂O/O₂/air. Anti-anesthetic interference characteristics ensure measurement stability, with RS485 output facilitating access to hospital gas management systems. Actual cases show that in retrofits of multiple high-end anesthesia workstations, the sensor achieved <±2% concentration deviation, compliant with YY 0670 and IEC 60601 series standards.

Portable Oxygen Therapy Equipment and Home Respiratory Rehabilitation
Low-power versions are suitable for lithium battery-powered portable oxygen concentrators and home ventilators, supporting BLE or UART interfaces for docking with mobile phone Apps to achieve patient oxygen concentration trend recording and anomaly alarms. In a home respiratory rehabilitation brand project, the sensor enabled remote physician monitoring and automatic oxygen concentration optimization.

Selection Guide and System Integration Considerations

Selection Key Parameters

• Range and Accuracy Requirements: Home oxygen concentrators prioritize 0–100%vol ±1.5% FS, ventilators/anesthesia machines recommend ±0.5% FS high-precision versions

• Output Interface: Digital UART/I²C preferred for embedded integration, 4–20 mA suitable for traditional PLC or legacy equipment retrofits

• Gas Path Adaptation: Standard quick connectors or custom diameters (6–10 mm), pressure drop<150 Pa

• Certification Compliance: Prioritize NMPA Class II medical device registration, ISO 13485, IEC 60601-1 electrical safety and EMC

• Power Consumption and Size: Portable devices select<50 mW low-power version, size ≤Φ30×50 mm

System Integration Considerations

• Gas Path Installation: Sensor should be placed after the steady flow section to avoid turbulence and condensate; recommended to install dehumidification filter and one-way valve

• Temperature Compensation: Utilize built-in high-precision temperature sensor (±0.2°C) for real-time sound velocity correction to avoid errors due to ambient temperature differences

• Electrical Interface: Digital output recommended with optocoupler isolation, 4–20 mA loop load ≤500 Ω, use three-wire configuration to reduce line resistance effects

• System Calibration: Factory NIST traceable multi-point calibration; recommend field verification with standard oxygen-nitrogen mixed gas every 12–24 months

• Closed-Loop Control: Oxygen concentration signal connected to main control MCU, combined with flow sensor for PID regulation of proportional valve, typical control cycle<200 ms

• Data Communication: UART default baud rate 9600/115200 bps, supports Modbus RTU mapping, convenient for access to hospital central monitoring system or cloud platform

OEM Customization and Bulk Supply Advantages

Nexisense provides full-chain medical-grade OEM/ODM services, including:

• Custom range, resolution, and temperature compensation curves

• Gas path interfaces (quick connectors, Luer locks, custom flanges) and form factor adaptation

• Output protocol and protocol stack development (custom Modbus registers, BLE GATT profile)

• Integration of flow/pressure multi-parameter modules (oxygen concentration + flow integration)

• Brand labeling, laser coding, and medical registration documentation support

Bulk supply covers thousands to hundreds of thousands of units, delivered in phases according to customer R&D/mass production rhythm, with tiered pricing, strategic stocking, and joint reliability testing. Long-term partners can participate in joint development of next-generation low-power, miniaturized, or multi-gas fusion ultrasonic modules.

Frequently Asked Questions (FAQ)

1. What are the main advantages of Nexisense ultrasonic oxygen sensor compared to traditional electrochemical oxygen sensors?
      No oxygen consumption, no poisoning risk, no need for periodic electrolyte replacement, longer service life (>10 years vs 2-3 years), strong resistance to anesthetic interference, suitable for long-term continuous monitoring.

2. How to ensure stability of oxygen concentration measurement in high-flow oxygen concentrators?
      Using transit-time difference method + high-precision temperature compensation algorithm, flow changes affect concentration measurement <±0.5%vol, combined with steady flow design to ensure uniform gas path.

3. How does the sensor control cross-interference from N₂O, CO₂, and other anesthetic gases?
      Through narrowband filter and sound velocity difference compensation algorithm, cross-interference <±1.0%vol (typical N₂O 50%), far superior to electrochemical solutions.

4. How to achieve rapid integration with ventilator main control board?
      Provide standard UART/I²C interface protocol stack, typical integration cycle<2 weeks, support real-time concentration + temperature dual-channel data reading.

5. How does the sensor perform in low-temperature environments (below 0°C)?
      Built-in temperature compensation range -10～60°C, accuracy maintained at ±1.8% FS at 0°C, optional heating module if necessary.

6. What is the minimum order quantity for OEM customized oxygen concentration + flow integrated modules?
      Standard integrated modules start at 1000 units, highly customized projects (including gas path structure) usually start at 3000 units, development cycle 8-14 weeks.

7. How does the system meet NMPA Class II medical device registration requirements?
      Provide complete technical documentation (design history, risk analysis, EMC/biocompatibility test reports), multiple products have obtained NMPA registration certificates.

8. What host computer communication protocols does the sensor support?
      Standard UART/Modbus RTU, extended support for CAN, BLE, LoRa, customizable according to ventilator or oxygen concentrator mainboard requirements.

9. Does bulk procurement provide per-batch factory calibration reports and consistency data?
      Yes, provides NIST traceable multi-point calibration certificates, batch statistical analysis, and third-party metrology verification support.

10. For home oxygen concentrator projects, what is the recommended concentration monitoring frequency and alarm strategy?
       Recommended 1 acquisition per second, set multi-level alarms (<85% warning, <80% alarm, <70% forced shutdown), linked to sound/light/remote push to ensure patient safety.

Conclusion

Nexisense is committed to providing high-reliability ultrasonic oxygen sensor solutions for medical oxygen concentrator, ventilator, high-flow oxygen therapy equipment, and anesthesia machine manufacturers. If your company requires sensor selection, integration verification, protocol adaptation, or OEM custom development support in R&D, production, or upgrade projects for medical gas monitoring equipment, welcome to contact us for in-depth discussion of specific technical requirements and cooperation plans. Together, we promote the development of medical oxygen therapy equipment toward higher precision, longer lifespan, and lower maintenance, safeguarding patient oxygenation safety.