| 被动扩散式检测管是用来测定较长时间下气体浓度的时量平均值（TWA），采用自然扩散的方式。 这种检测管里面填充有吸附剂及反应剂，气体以一定的速率被均匀吸附，从而出现较为明显均匀的变色。 检测工作场所人员的有害气体暴露量时，用右图的检测管夹（710）放置在人员衣领处即可。 检测有害气体在工作场所的分布时，把该检测管固定放置一段时间后就可检测出来。也可用来进行长时间的检测。 | |
特点 简洁，轻巧，方便多用 直接读数 不需取样设备 图例 A-切断处 B-吸附剂 C-检测剂 | 检测管夹 No. 710 |
日本174D丁二烯检测管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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