An in-depth look at Vaisala’s hydrogen peroxide sensor technology

加入我们，与Vaisala的行业专家Piritta Maunu和Sanna Lehtinen进行1小时的培训。Piritta和Sanna将涵盖测量过氧化氢生物污染湿度的关键方面。当监测蒸发过氧化氢过程时，该网络研讨会的重点将是相对饱和参数的关键作用。

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HPP270系列探针可以测量的最低PPM是什么？

The measurement range is from 0 to 2000 ppm ±10 ppm or ±5% of the reading (whichever is greater) at 25 °C. The accuracy specifications are stated from 10 ppm onwards. TheHPP270series probes (HPP271 and HPP272) are not intended for safety level ppm measurements.

探针是否可以承受冷凝？

The probe must always be powered on when there is H₂O₂in the probe’s environment. When powered on, thePEROXCAP传感器加热，允许在冷凝H中使用探针₂O₂conditions, maintains measurement performance, and lengthens the probe’s lifetime. If the probe is exposed to H₂O₂电源关闭时，传感器可能会功能障碍并且不会恢复。最坏的情况下，探针在较高温度下持续一天，h₂O₂in high concentration, under near condensing conditions, the probe would not survive. Refer to theproduct specifications for HPP270 series, under “Operating Environments.”

Can the probe measure liquid H₂O₂?
No, the HPP270 series probes are for vaporized hydrogen peroxide measurement.

Does the probe withstand peracetic acid or acetic acid blends?

蒸发过乙酸是一种非常氧化剂，因此在该环境中，过氧cap传感器将无法生存。

Does the probe withstand silver ion blends?
It is not recommended to use the probe with silver ion blends since the silver particles can block the porous filter and therefore deteriorate gas exchange to腐殖质传感器在过滤器中。

我的客户有H₂O₂真空下的蒸气灭菌。我们可以在真空中使用此探针吗？

该探针并非设计用于真空条件。

Can I use this probe in over / under pressure?
The probe is designed for normal atmospheric pressure only.

Are Relative Humidity and Relative Saturation measured directly from the sensor?
直接测量相对湿度并计算相对饱和。（在this webinar）

Which parameters does the HPP271 and HPP272 output?
The HPP272 outputs H₂O₂concentration (ppm), temperature and humidity (Relative Saturation and Relative Humidity); The HPP271 outputs H₂O₂ppm按音量和h₂O ppm by volume.

为什么Mg/m³而不是mg/L的绝对氢过氧化单元？
We have chosen the International System of Units (SI) mg/m³, whereas mg/L is not an SI unit.

如何将mg/l转换为mg/m³
Absolute H₂O₂mg/m³（每立方米毫克）可以通过使用此公式将其转换为mg/l（每升毫克）：

为什么HPP271仅输出H₂O₂ppm and not Relative Humidity and Relative Saturation?
The HPP271 sensor contains aPEROXCAP sensorwith two composite腐殖质传感器。为了在高度冷凝的环境中提供稳定，准确且可重复的测量，过热的传感器会加热。相对湿度和相对饱和都是温度依赖性参数。由于传感器被加热，因此，如果需要准确的温度测量，则需要额外的温度传感器。HPP271没有此额外的温度传感器。

How is the HPP272 ppm H₂O calculated - on a “wet” or “dry” basis?
H₂O ppm is calculated on a “wet” basis.

What kind of heating functions does the sensor have?
When powered on, the PEROXCAP sensor is heated (i.e. only the sensor chip under the filter cap is heated, not the probe itself). This prevents condensation from forming on the sensor and provides reliable measurement even in environments where humidity is near saturation. Heating also helps to maintain measurement performance and lengthens the probe's lifetime. The chemical purge heats the sensor at certain intervals. Heating results in rapid evaporation of the chemical contaminants that have been absorbed into the polymer. Chemical purge thus cleans the sensor internally, improving its stability and accuracy. More on this function below...

Which parameters are shown on the Indigo200 series displays when the HPP272 probe is connected?
The display will always default to H₂O₂ppm, Relative Saturation and Temperature. TheIndigo201’sanalog outputs 1 and 2 follow the HPP272 analog outputs when first connected to Indigo201. After that, the user may change the analog outputs and display settings. These will remain even if you detach the probe and reconnect it. Note, only the Temperature value is displayed for the first 8.5 minutes during start-up.

What is a Chemical Purge?
通过强迫通过传感器的温度元件迫使电流在化学吹扫过程中迅速加热传感器。这种快速的加热导致可能已吸收到聚合物中的化学污染物的蒸发。因此，化学清除可以清洁传感器，从而提高其稳定性和准确性。化学吹扫周期需要几分钟才能完成，包括加热和平衡阶段。当传感器温度在清除之前重新稳定为条件时，传感器以正常测量模式继续。在化学清除期间，发射器的值输出锁定。

何时发生化学清洗？
The purge (interval purge) is automatically performed at probe start-up and set intervals. The default chemical purge interval is 24 hours, or configurable between 1 hour to 1 week using Vaisala Insight software, Modbus, or Indigo200 transmitters. However, the chemical purge is postponed by 30 minutes if H₂O₂is present or Relative Humidity is unstable.

You can also trigger a purge manually with Modbus (in digital mode) or pin #5 on the M12 connector (in analog mode). The interval purge is postponed by its set value every time you trigger the purge.

Can I disable the chemical purge at start-up or during the bio-decontamination cycle?
不，化学清除对于要求H的长期性能和探测的准确性至关重要₂O₂environments. Chemical purge is needed at probe start-up to maintain sensor stability. During the purge, H₂O₂和h₂O measurements are not available.

How often is chemical purge recommended?
It is not the frequency of purge processes that is important, but how long the probe is within an environment with H₂O₂present. Purge is recommended at least every 24 hours of powered-on time, even if the probe has not been continuously exposed to H₂O₂。如果使用触发的清除，我们建议在生物污染周期之前实施清除。
Note, that it takes approximately 9 minutes to return to accurate readings after a purge. The maximum interval is weekly. Chemical purge is needed to maintain the stability of the measurement and if chemical purge is not performed, the measurement will drift.

化学清洗期间可以使用哪种测量？
During the purge, only temperature measurement is available (HPP272). During interval and manually triggered purges, the value output is frozen to show the last measured value before the purge began.

Can I do an on-site calibration and adjustment?

You can calibrate and adjust the probe directly in H₂O₂vapor withInsight PC software（Insight 1.0.1.107开始）。请注意，H中的校准₂O₂vapor is a highly advanced procedure that can be performed reliably only by using another Vaisala HPP270 series probe as a reference instrument and successfully creating matching measurement conditions for both the reference probe and the probe that is being adjusted.You can perform an on-site calibration and adjustment with any RH calibrator, for example:HMK15, or with Insight PC software (Insight 1.0.1.107 onwards).

我们如何调整H₂O₂measurement with RH?
The PEROXCAP sensor comprises two HUMICAP humidity sensors that are used to calculate the H₂O₂测量。Because the H₂O₂测量基于湿度计算，您可以使用湿度参考来调整潜在的湿度测量。提高基本湿度测量的准确性也提高了派生h的准确性₂O₂测量。