产品详情
简单介绍：
甲醛检测管91D，GASTEC甲醛检测管91D检测范围0.1-20ppm，检测管检测时间在1-10小时左右。甲醛检测管91D采用自然扩散的方式。其特点：简洁，轻巧，方便多用、直接读数、不需取样设备。
详情介绍：
甲醛检测管91D，GASTEC甲醛检测管91D检测范围0.1-20ppm，检测管检测时间在1-10小时左右。甲醛检测管91D采用自然扩散的方式。其特点：简洁，轻巧，方便多用、直接读数、不需取样设备。
| 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。也可用来进行更长时间的检测。 |
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特点
简洁，轻巧，方便多用 直接读数 不需取样设备 |
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Formaldehyde |
NO.91D |
| HCHO |
Performance
| Measuring Range | 0.1 to 20 ppm |
| Sampling Hours | 1 to 10 hours |
| Detecting Limit | 0.05 ppm (10 hours) |
| Colour Change | Yellow → Reddish Brown |
| Reaction Principle |
3HCHO + (NH2OH)3 H3PO4 → H3PO4 |
| Coefficient of Variation | 10% (for 1 to 20 ppm-hr) |
| Shelf Life | 1 Year |
| Corrections for temperature & humidity | Unnecessary |
| Store the tubes in the refrigerator to keep at 10ºC (50ºF) or below. | |
Possible coexisting substances and their interferences
| Substance | Interference | Change colour by itself to |
| Aldehydes, Ketones, Acid gases | + | Reddish brown |
Other substance measurable with this detector tube
| Substance | Correction Factor | Sampling Time | Measuring Range |
| Acetaldehyde | 1.0 | 1 to 10 hours | 0.1 to 20 ppm |
| Furfural | 3.0 | 1 to 10 hours | 0.3 to 60 ppm |
| Methyl ethyl ketone | 1.25 | 1 to 10 hours | 0.125 to 25 ppm |
| Calibration gas generation | Diffusion tube method |
| TLV-TWA | TLV-STEL | Explosive range |
| - | C 0.3 ppm | 7.0 to 73% |