对于许多人来说，永远不需要获得超准确的湿度阅读。当然，如果空气太干，您可能会打开加湿器，或在潮湿的地下室中运行除湿机。但是很少有人关心室内湿度是58％还是60％。也就是说，您可能需要非常准确的阅读原因很多。例如，许多电子设备可能对湿度的变化敏感。因此，如果您正在运行服务器室，则可能需要提醒您甚至进行较小的更改。同样，许多商业HVAC系统都内置了加湿器。如果您是研究其中一种系统的技术人员，那么拥有可以测量湿度的工具很重要。
But there are any number of tools for the job. For instance, you could use awireless hygrometer。这se track the current humidity, and can even monitor other weather conditions. However, they’re not quite as accurate as a proper psychrometer. They’re better-suited for continuous monitoring than they are for spot checking. If you want the maximum accuracy from a handheld device, the right tool is a digital psychrometer.
Today, we’re going to review three of the best digital psychrometers that money can buy. First off, we’re going to discuss the UEi Test Instruments DTH35 Digital Psychrometer. This is a powerful, accurate psychrometer with an easy-to-read triple display. Next, we’ll look at the Preciva Digital Psychrometer. This is an affordable, handheld psychrometer that sports an ergonomic rubber grip. Finally, we’ll examine the Extech RH350 Psychrometer. This psychrometer will store up to 99 data records, and also includes two remote temperature probes. To find out which is the best, we’ll have to take a close look at each of them. Let’s get started, and see how they perform!
什么是心理计？
大多数人都熟悉湿度计。他们可能无法告诉您一个人的工作原理，但他们知道它可以衡量湿度。但是“心理计”是一个不太熟悉的词，甚至可能令人困惑。实际上，心理计只是一种特殊类型的湿度计。
First developed in the 1600s, a psychrometer consists of two thermometers. Because old-school mercury thermometers have bulbs at the bottom, they’re referred to as bulbs in this case. One is called the dry bulb, and is exposed to the air just like any other ordinary thermometer. The other is called the wet bulb, and is wrapped in wet cloth or cotton wadding. You then allow the wet bulb to cool until the temperature stops dropping. Depending on the design, you may need to swing the wet bulb around during this time. Once the wet bulb has stopped cooling, you can measure the difference between it and the dry bulb. Then, combined with a measurement of the local atmospheric pressure, you can determine the humidity.
This works based on the principle of evaporative cooling. In dry air, a great deal of moisture will evaporate from the wet bulb. This in turn will lower the bulb’s temperature by a large margin. On the other hand, in humid air, there will be less evaporation, and therefore less cooling. At 100 percent humidity, you wouldn’t see any temperature differential at all.
为什么使用数字心理计？
正如您现在可能已经猜到的那样，使用老式手动心理表并非野餐。首先，您必须校准（而不是破裂）一对准确的汞温度计。仅此过程就可以长达20到30分钟。然后，您必须弄湿布。然后，您必须摆动它，并使用另一种工具来读取气压压力。即使进行了测量，您也必须在图表上查找所有内容。
A psychometric chart contains a variety of information in addition to the humidity. You can also find a variety of other information. Among other data, you could find:
- 露点或水蒸气将开始凝结的温度。如果温度下降到这一点，露水将开始形成。
- 湿度比或水分与空气的重量之比。
- 特定的体积或特定数量的空气占用多少空间。
- 焓，或每磅空气中的热量。
可以想象，这是很多数据。此外，所有数据都包含在带有多列的图表中。美国农业部的1915年图表长87页。只是为了获得一些简单的阅读，这是一个巨大的麻烦。但是在计算机之前的几天里，这是我们最好的方法。亚洲官方合作伙伴
如今，数字心理计可以在短短几秒钟内完成相同的工作。您实际上按下按钮，读取出现在屏幕上。就简单性而言，它确实不会变得更容易。无需在空气中摆动温度计或翻转繁琐的90页图表。您不必是实验室科学家即可使用其中一种设备。他们只需几分钟的培训就可以由任何人操作。
With a digital psychrometer, you can also take advantage of other modern features. For instance, many will allow you to store previous readings for later recall. You can also switch between different units of measurement. In most cases, there will be an option to switch between Fahrenheit and centigrade, for example. You can also use remote probes and other fancy gadgets. That’s not possible with a manual psychrometer.
UEI测试仪器DTH35数字心理计
这UEI测试仪器DTH35数字心理计is a handheld, wand-shaped device. Its housing is constructed from bright yellow plastic, which is both high-visibility and reasonably durable. The overall length is just under 10 inches but most of that is the probe. The screen is located towards the base of the wand, and measures just under two inches in height. At three inches in width, it’s also large enough to be easily readable. There’s even a probe cover that doubles as an extension handle that can be attached to the other end. The DTH35 comes individually by default. However, if you’re outfitting a larger crew, you can also buy it in a two, three, or four-pack.
该显示可以同时显示两次读数。默认情况下，您会看到温度和相对湿度，但是还有其他选择。您也可以使用UEI心理计计算露点或焓。温度可以在Centigrade或Wahrenheit中显示，因此适合在任何国家使用。而且，无论您测量什么，屏幕都很容易阅读。它具有背光设计，因此即使在黑暗中，您也可以接受阅读。背面还有一个磁性安装座，因此魔杖可以连接到导电表面。这意味着您可以在写下读数时将其拍在空气管的侧面。
这DTH35 can operate between 32 and 122 degrees Fahrenheit. This covers most ordinary circumstances where you’ll actually care about the humidity. The lower limit for the wet bulb and dew point readings is even lower, at -69 and -90 degrees respectively. You can measure the full gamut of relative humidity, from 0 to 100 percent. Once you’ve taken your readings, you can save a min/max reading. This will allow you to recall your highest and lowest readings at the push of a button. If you want to start fresh, you can also reset these readings.
Preciva数字心理计
这Preciva数字心理计是一个更实惠的选择，但这并不意味着不值得考虑。首先，它的形状很小，就像一个对讲机一样。实际上，它看起来像个对讲机，中间的简短探头呈现出脂肪天线的外观。总长度小于七英寸，宽度不到三英寸。
显示屏位于中间，带有白色背光和易于阅读的数字。它显示了顶部的相对湿度以及下方的当前温度。湿度显示为百分之一的百分之一，温度达到一百个度。在下面，您会发现一个在不同模式之间骑自行车的按钮，包括从摄氏摄影变为华氏。还有一个最小/最大内存按钮。设备的侧面有小橡胶握把，因此不会从潮湿或出汗的手中滑出。
Preciva心理计可以测量32至104华氏度之间的相对湿度。湿球温度的升高可能高达176度。对于露点，您的范围为-4至176度。这是温度读数的限制。总共可以测量0％至100％。因此，即使在非常潮湿或非常干燥的条件下，您仍然可以使用此心理计。
Extech RH350心理计
Extech是工业测试设备的著名制造商。除其他产品外，我们已经审查了他们的数字轻度仪in the past. TheirRH350 Psychrometer辜负他们的质量传统。它是漫长而绿色的，探针很短。这听起来像是一件坏事，但是Extech包含包装中的一对远程探针。您可以在没有它们的情况下快速阅读，也可以将它们滑入较小的空间以获得更准确的阅读。
外壳的颜色为橄榄绿色，正面有几个按钮。这些按钮是必要的，因为心理计的高级功能。您需要在内置和远程探针之间切换，更改温度尺度和更改读数。您还需要能够使用内存功能。总共RH350可以存储99个不同的数据记录。这足以跟踪荒谬的项目。您还可以使用一个按钮存储简单的最小/最大读数。
普通工作温度为-4至122度，令人印象深刻。湿度可以读取10％至90％，露点从-90到122度。湿球甚至可以测量低至-6.9度的温度。这些功能结合在一起，使其成为可用的通用性心理仪之一。
最终判决
这些数字心理仪中的每一个都有其自己的宝贵功能，可以带来桌面。哪一个最好的将在很大程度上取决于您的需求。这UEI测试仪器DTH35数字心理计对于大多数应用程序，是一个不错的全方位选择。它的魔杖形设计使得将探针插入紧密的空间并获得阅读。扩展手柄使其易于固定，并且易于阅读背光显示器。您在这里找不到很多“额外”功能。没有远程探测器，并且内存功能只是一个简单的最小/最大值。也就是说，它非常敏感，易于使用，并且适用于机组人员。
下一个在我们的清单上，我们审查了Preciva数字心理计。这是我们最负担得起的选择，并提供最少的阅读选项。也就是说，这对于您获得的东西是一个巨大的价值。您可以在大多数正常温度下使用它，并且具有适当的最小/最大功能。它还具有漂亮的橡胶握把，使其非常容易握住。如果您只需要简单的湿度读取而没有任何附加功能，那么您就可以选择一个可靠的选择。
这Extech RH350心理计is what you buy when you’re willing to pay top dollar for top quality. With remote probes, you can measure the temperature and humidity in even the tightest of spaces. Moreover, you can use this psychrometer in virtually any conditions. Finally, you can store 99 different records, which makes it easy to track all your projects. If you need these features, the RH350 is an excellent option.
