温度探针的热阻尼：何时，何时以及为什么

We often receive questions from customers on the use of thermal damping devices on temperature probes. We have another blog on this topic:“疫苗和医学温度监测应用中的热阻尼。”在那里，您会发现两个良好的引用（来自NIST和CDC），指的是使用热阻尼器。

In this week’s blog, we have a more in-depth discussion on where and when to use a buffering device, and why.

保罗写道：

For mapping studies, I usually advise against damping the measurements. Almost every controlled environment we map provides a stable environment for the stored item by bathing it in temperature-controlled air. The temperature of the stored item is dependent on the temperature of the air. The air temperature will fluctuate based on normal control cycles and the stored product temperature will fluctuate accordingly. The product temperature will fluctuate less, as it will always have a higher specific heat than the air, and the product will experience temperature fluctuations that are "damped" relative to the air temperatures. Products generally have a higher thermal mass than air. The actual air temperature represents the worst-case scenario. Product temperature (which we can think of as a damped signal) will always show less fluctuation than air. As validation professionals we always want to address the worst-case scenario, so measuring the undamped air temperature is the right choice; both easy to defend, and easier to do.

是否有任何情况下，我们会在映射时抑制探测器？当我们测量空气温度时，当环境无法正确执行时，这是一个问题。这通常是1）设备故障的症状，或2）不适合任务的设备。在这些情况下，采用映射练习，阻尼的空气信号只是隐藏了设备故障或设备不合适的基本问题。

但是，当验证专家说阻尼的气温只是隐藏了不良设备时，这很少意味着您的客户会神奇地获得购买新设备的预算。更有可能的是：客户将推进他们的计划，以使用故障设备进行映射，并希望您（验证专家）找到适当的解决方案。当验证放在结尾of the project, rather than the beginning.

不管是什么原因，您都面临挑战。我的建议是在空气中绘制裸传感器，未阻尼信号，以查看环境在将气温映射为最坏情况的情况时是否可以满足验收标准。即使您期望它将失败，也要这样做。一旦失败，您就有一个基本原理可以使用阻尼信号来支持，并且您将根据原始研究数据知道可能需要多少阻尼。

让我们假设我们现在已经是：您在空气中映射，数据没有符合接受标准，因此您需要再次映射。检查将在环境中存储的内容。您不希望传感器的人工阻尼超过环境中存储的最小物品的自然阻尼。例如，如果环境中存储的最小物品是液体产品的50毫升小瓶，那么我们希望使用较小的安慰剂产品（例如20毫升的乙二醇小瓶）来放置我们的传感器。我认为您明白了……如果存储的产品对温度比我们用来绘制环境的传感器更敏感，那么我们的研究将被妥协（阅读“毫无意义”）。而且，当我们完成映射时，将需要该环境的程序控制，以确保没有小于50毫升的产品存储在该地区。

因此，您可以潮湿的空气温度信号。但是，我认为这通常只是掩盖故障或不适当的设备。它将受到审计的问题。它将需要为映射环境进行持续的程序控制。

Now you may ask: Does this logic apply to constant monitoring after the mapping has been completed and units are in use?是的，否。监视是另一个故事。映射是使用挑战场景（例如最坏情况示例）可靠地显示过程的验证。监视是质量控制，以确保过程正确运行。可是等等！有一些变量需要考虑…

通过监视，您理想地，您可以根据映射研究得出的信息选择传感器位置，通常是警报限制。为了使此过程具有一定的连续性，我们希望监视过程将遵循我们的映射过程。换句话说 - 如果我们开始抑制信号以监视，我们是否有合理的期望我们的数据可以比较？我们将以未在映射研究中使用的方式监视该过程，然后期望能够与数据进行比较。

但这通常是人们做的。他们只是将监视探针贴在腔室中，用乙二醇或某些溶液湿warm污染物，不要再考虑一下。根据我的经验，大多数审计师不会对此发表任何意见。You have validated your chamber by mapping, you are monitoring with a validated monitoring system, and even if the damped monitoring data isn’t comparable to your mapping, or proven to be equivalent to your typical load, at least it will capture catastrophic failures in your chamber – power loss, compressor failure, door left open, etc.

You can probably tell that I prefer monitoring in air temperature. I don’t mind the problems that it brings because I don’t think of them as problems. The disadvantages of monitoring air temperature are that the temperatures change faster and respond more easily to environmental perturbations such as leaving the chamber door open or adding the product of a different temperature.

However, these perturbations are things that represent a chamber that is not be properly managed. With well-trained personnel, doors aren’t left or held open. With proper handling procedures, new stock is conditioned at the appropriate temperatures before it is placed in our chamber. However, with a damped monitoring signal – these“problems” (which are usually indicators of poor processes, ineffective training, and failing equipment) go away. I personally think they shouldn't be hidden and like that the undamped signal of air temperature in your chamber can tell you about more than the performance of your refrigerator, it can tell you about the performance of your department. Furthermore, with an advanced monitoring system, like our viewLinc CMS, you can use alarm delays to achieve many of the same effects as a damped signal without losing the data sensitivity. This is a better use of technology to give honest data and set up smart monitoring.

So what are the major disadvantages and advantages of a damped signal? On the positive side: damped signals offer simplicity in operation. You can install and forget. On the negative side: you risk a mess from spilled damping fluid in high traffic areas. And you risk a mess in the logic of your monitoring process because the data is not truly representative of what the product is experiencing. You will lose the ability to evaluate deviations unless you know that your damped signal is still more sensitive than your product. One possible solution would be to do a study to ensure that your damped monitoring signal is approximating your product.

我们已经看到一些行业成功地潮湿监测信号，例如眼/角膜库，指南指定将传感器放置在20毫升Optisol中，因为这是存储角膜的推荐方法。但是，眼库仅在角膜上进行交易，并且所有角膜都非常相似。

在该领域，我们已经看到大多数人都会潮湿监视信号，而不必担心后果。我不建议这样做，但是很普遍，因此在审核中不太可能伤害您。

如果您有任何经验可以在何时何地使用热缓冲区（包括您用作阻尼设备的用途），请与我或我的同事Piritta Maunu联系。

Survey on Single-Point Calibration

上周我们博客如何执行单点校准with a video. The response to that video was great! Thank you to all who read the blog.