| 被動擴散式檢測管是用來測定較長時間下氣體濃度的時量平均值（TWA），采用自然擴散的方式。 這種檢測管里面填充有吸附劑及反應劑，氣體以一定的速率被均勻吸附，從而出現較為明顯均勻的變色。 檢測工作場所人員的有害氣體暴露量時，用右圖的檢測管夾（710）放置在人員衣領處即可。 檢測有害氣體在工作場所的分布時，把該檢測管固定放置一段時間后就可檢測出來。也可用來進行長時間的檢測。 | |
特點 簡潔，輕巧，方便多用 直接讀數 不需取樣設備 圖例 A-切斷處 B-吸附劑 C-檢測劑 | 檢測管夾 No. 710 |
日本174D丁二烯檢測管1.56-240ppm
Performance
| Measuring Range | 1.3 to 200 ppm |
| Sampling Hours | 1 to 8 hours |
| Detecting Limit | 1.3 ppm (8 hours) |
| Colour Change | Reddish purple → Pale brown |
| Reaction Principle | CH2:CHCH:CH2 + MnO4 仺 Pale brown product |
| Coefficient of Variation | 10% (for 10 to 200 ppmr) |
| Shelf Life | 2 Years |
| Corrections for temperature & humidity | Temperature correction is necessary |
| Store the tubes at cool and dark place. | |
Possible coexisting substances and their interferences (NOTE)
| Substance | Interference | Change colour by itself to |
| Unsaturated hydrocarbons | + | Pale brown |
Other substance measurable with this detector tube
| Substance | Correction Factor | Measuring Range |
| Ethylene | Factor: 1.2 | 1.5 to 240 ppm |
| Vinyl chloride | Factor: 1.2 | 1.5 to 240 ppm |
| Isoprene | Factor: 2.0 | 2.5 to 400 ppm |
| Trans-1,2-Dichloroethylene | Factor: 3.0 | 3.8 to 600 ppm |
| Calibration gas generation | Permeation tube method |
| TLV-TWA | TLV-STEL | Explosive range |
| 2 ppm | - | 2.0 to 12% |
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