7ETO-100 Ethylene Oxide Gas Sensor For Medical Device Sterilization Pharmaceutical Manufacturing
The 7ETO-100 operates on the electrochemical detection principle, leveraging a three-electrode cell immersed in an electrolyte solution:
- Gas Diffusion: Ethylene oxide gas in the environment diffuses through a porous membrane (gas-permeable membrane) into the sensor’s internal electrolyte.
- Electrochemical Reaction: At the working electrode (cathode), ETO undergoes oxidation, producing electrons, protons (H⁺), and harmless byproducts (e.g., CO₂, H₂O).
- Current Generation: The electrons generated by the oxidation reaction flow through an external circuit to the counter electrode (anode), creating a measurable electrical current. The magnitude of this current is linearly proportional to the concentration of ETO in the sample gas (per Faraday’s Law of Electrolysis).
- Stability Maintenance: The reference electrode provides a stable voltage reference, preventing drift in the working electrode’s potential and ensuring long-term measurement accuracy.
4. Typical Applications
The 7ETO-100 is engineered for scenarios requiring ETO monitoring, with core use cases including:
4.1 Medical Sterilization Industry
Ethylene oxide is widely used to sterilize heat-sensitive medical devices (e.g., surgical instruments, syringes, implants). The 7ETO-100 is integrated into:
- Sterilization Chamber Monitors: Real-time tracking of ETO concentration during the sterilization cycle to ensure effective microbial inactivation.
- Post-Sterilization Ventilation Systems: Detection of residual ETO in sterilized equipment or exhaust air, ensuring levels meet safety standards (e.g., ≤ 1 ppm for personnel exposure) before devices are used or air is released.
4.2 Chemical & Pharmaceutical Manufacturing
In facilities producing ETO or using ETO as a raw material (e.g., for ethylene glycol synthesis, detergent production):
- Fixed-Point Leak Detectors: Installation near pipelines, valves, or reaction vessels to trigger alarms if ETO leaks occur (preventing toxic exposure or fire risks).
- Process Control Systems: Monitoring ETO concentration in reaction streams to optimize production efficiency and ensure product quality.
4.3 Environmental & Occupational Safety
- Portable Gas Detectors: Used by maintenance workers, laboratory staff, or emergency responders to monitor personal exposure to ETO in confined spaces (e.g., sterilization rooms, chemical storage areas) or during leak investigations.
- Indoor Air Quality (IAQ) Monitors: In facilities where ETO may accumulate (e.g., hospitals, pharmaceutical plants), the sensor ensures indoor ETO levels comply with occupational health regulations (e.g., OSHA’s permissible exposure limit (PEL) for ETO: 1 ppm over an 8-hour workday).
4.4 Food Processing (Optional)
In some food sterilization applications (e.g., low-temperature sterilization of packaged foods), the 7ETO-100 monitors residual ETO to ensure food safety and compliance with global food standards.
5. Installation & Operation Guidelines
5.1 Installation Notes
- Location: Mount the sensor in areas where ETO is likely to accumulate (e.g., near sterilization chambers, ETO storage tanks) or where personnel frequent. Avoid direct sunlight, extreme temperatures, or high-humidity (condensing) environments.
- Gas Inlet: For diffusion-type sensors, ensure unobstructed air flow around the sensor (minimum 5 cm clearance from walls/obstacles). For pump-type sensors, connect the gas inlet tube to the sampling point (tube length ≤ 2 meters to avoid response delay).
- Wiring: Follow the sensor’s pinout diagram (provided in the datasheet) for power and signal connections. Use shielded cables for analog signals to reduce electromagnetic interference (EMI).
5.2 Calibration
- Initial Calibration: Perform a two-point calibration (zero calibration with clean air, span calibration with a known ETO concentration gas) before first use.
- Routine Calibration: Recalibrate every 3–6 months (or as required by local regulations) to maintain accuracy. Calibration gas should be certified (NIST-traceable or equivalent) with a concentration close to the sensor’s full scale (e.g., 80 ppm for a 0–100 ppm sensor).
5.3 Maintenance
- Cleaning: Periodically wipe the sensor’s exterior with a dry, lint-free cloth. Do not use solvents or water on the gas inlet membrane.
- Replacement: Replace the sensor if: (1) response time exceeds 60 seconds, (2) accuracy deviates by >10% of FS after calibration, or (3) the sensor reaches its rated lifespan.
6. Safety Precautions
- Toxic Gas Risk: Ethylene oxide is toxic and carcinogenic—always wear appropriate PPE (e.g., gas mask, gloves) when handling ETO or performing sensor maintenance in potentially contaminated areas.
- Flammability: ETO is flammable (explosion limit: 3%–100% by volume in air)—avoid installing the sensor near open flames, sparks, or high-temperature surfaces.
- Sensor Handling: Do not disassemble the sensor (risk of electrolyte leakage, which may cause skin irritation). Dispose of old sensors in accordance with local hazardous waste regulations.
Parameter Category | Parameter Name | Specification | Unit | Remarks |
Target Gas & Sensing Principle | Target Gas | Ethylene Oxide (EO/ETO) | - | Specialized for EO detection; not compatible with other toxic gases |
| Sensing Principle | Electrochemical (Three-electrode Structure: Working/Counter/Reference Electrodes) | - | Ensures high selectivity and low signal drift |
Measurement Performance | Detection Range | 0 ~ 100 | ppm | Custom ranges (0~50 ppm, 0~200 ppm) available upon request |
| Resolution | ≤ 0.1 | ppm | Minimum detectable concentration change |
| Accuracy | ±5% FS (Full Scale) or ±2 ppm, whichever is larger | - | Tested under standard conditions (25℃, 1 atm, 50% RH) |
| Response Time (T90) | ≤ 30 | Seconds | Time to reach 90% of stable output signal |
| Recovery Time (T10) | ≤ 60 | Seconds | Time to drop to 10% of stable output signal |
Electrical Characteristics | Power Supply Voltage | 5.0 ± 0.2 | V (DC) | Regulated power required; avoid overvoltage |
| Operating Current | ≤ 50 | mA | Typical value during continuous operation |
| Output Signal Type | Option 1: Analog (4 ~ 20 mA DC); Option 2: Analog (0 ~ 5 V DC); Option 3: Digital (UART/I2C) | - | Select output type when ordering |
| Signal Linearity | ≥ 99% | - | Factory-calibrated; no external linearization needed |
Environmental Adaptability | Operating Temperature Range | -10 ~ 50 | ℃ | Avoid condensation or extreme temperature fluctuations |
| Storage Temperature Range | -20 ~ 60 | ℃ | Store in dry, dust-free environment |
| Operating Humidity Range | 15 ~ 90 | % RH | Non-condensing; humidity >90% RH may affect accuracy |
| Atmospheric Pressure Range | 86 ~ 106 | kPa | Suitable for most low-altitude industrial/medical sites |
Mechanical & Physical Specs | Housing Material | Option 1: ABS Plastic (Standard); Option 2: 316L Stainless Steel (Harsh Environment) | - | Stainless steel option resists corrosion |
| Gas Intake Mode | Option 1: Diffusion (Passive); Option 2: Pump-driven (Active) | - | Diffusion for general use; pump-driven for long-distance sampling |
| Overall Dimensions (L×W×H) | 45 × 30 × 20 (ABS version); 50 × 35 × 25 (Stainless Steel version) | mm | Excludes connector/probe; refer to 2D drawing for exact size |
| Weight | ≤ 30 (ABS version); ≤ 80 (Stainless Steel version) | g | Net weight (excluding cables/fittings) |
Lifespan & Maintenance | Typical Operational Lifespan | ≥ 2 | Years | Under continuous operation in clean air (EO concentration < 1 ppm); lifespan shortens in high-concentration EO |
| Calibration Interval | 3 ~ 6 | Months | Recommended for maintaining accuracy; use NIST-traceable EO calibration gas |
