Fundamentals of foam concentrate systems for engine company operations
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最近，我被要求带领一堂关于使用泡沫作为新的新兵消防员课程的课程，这使我有机会自己回顾这个话题。与软管工作或梯子工作相比，泡沫不是一个流行的话题，但这仍然很重要。
Foam has been an integral part of the fire service and has a variety of applications. Notably it is known to be used for vehicle fires and Class B liquid fires, but now has capabilities to be used for Class A and wildland fires as well. In this article, let’s review foam concentrate systems as opposed to compressed air foam.
如今，大多数消防车都配备了泡沫系统，在该系统中生产自动混合物和泡沫产品的排放。即使大多数消防车都会拥有这种系统，但没有一辆没有一辆的卡车或何时何时在机上泡沫系统本身停止工作……我们如何产生泡沫？
我们必须回到泡沫生产的开始，消防员使用了带有或不带有喷嘴附件的泡沫导体。通过使用这些设备，我们可以生产成品泡沫。
相关的消防员培训
喷嘴附件旨在通过将更多的空气捕入水流中以帮助混合物来产生较厚的成品泡沫。所需的泡沫越厚，与浓缩的泡沫产物一起需要越多的充气。使用喷嘴附件的选择取决于消防部门的操作。消防服务中使用的每一个喷嘴都会产生成品泡沫产品，甚至是光滑的孔喷嘴.
In photo number 1 we can see a光滑的孔喷嘴流水产生固体流。有了这条实心流，我们可以通过将流到地面上的流或将其指向天空以产生流的降雨效应来产生成品泡沫。通过使用这三种方法之一，我们可以为A类和B级火灾产生成品泡沫。
在照片2中，您可以看到正在使用狭窄的雾图。使用这种类型的图案或喷嘴，将以与上述相同的方式生产成品泡沫，并产生更多的充气。如照片2所示，加上组合喷嘴的泡沫管，消防员可以产生更厚的成品泡沫。这将通过从侧面吸取更多空气与水和泡沫浓缩物混合来实现。
The eductor is the key piece of equipment needed to make foam. It is used to mix both the foam concentrate along with the water so that it can then be aerated at the nozzle. In photo 3 you will see an example of such an eductor.
The eductor will sit on top of the foam pail or can be attached to the pump discharge directly with the wand inserted into the foam pail. The position of the eductor in the hoseline is also important, as it must be within a certain distance from the nozzle (the general rule is within 100 feet of the nozzle). Depending upon how much hose has been pulled and is being used, the eductor will be positioned no more than 100 feet back from the nozzle.
Why? This is because of the higher pump pressure that must be used to make the eductor work properly. The pump discharge will be higher than normal automatically, not accounting for friction loss of the hose lengths added from the pump panel out. The higher pressure is needed to push the water through the hose towards the eductor, where it will decrease down in size to a ½-inch diameter size hole and then back to the normal 1 ½-inch (38mm) diameter size opening. This decrease in the diameter of the eductor creates a Venturi effect, which produces a vacuum drawing up the foam concentrate into the hose line.
The foam eductor needs to be set to the proper percentage for foam solution added. At the top of the eductor is a dial which allows the user to select the proper percentage – just turn to the desired amount and start flowing water. Once flowing, the foam solution will be used up. Depending on the percentage being used, it can go quickly, so keep a watchful eye on the level of the foam and be ready to switch out the wand of the eductor into a new foam pail. You will want to have multiple foam pails in one area right by the foam eductor set up so that quick changeover can be conducted without interrupting the operation.
一旦结束了泡沫操作，就必须冲洗系统。这可以通过两种方式之一来完成：使用一桶清水或去影剂上的冲洗按钮。在照片4中，您将看到所使用的排放量的冲洗功能。只需按下红色按钮，然后保持流水。如果用一桶清水，将魔杖放入水桶中，保持流动的水，直到不再产生泡沫为止。
Mark van der Feyst自1999年以来就一直在消防部门，是格拉蒂奥特堡（MI）消防局的消防员。他是加拿大，美国和印度以及FDIC的国际教练。他还是Residential Fire Rescue(Fire Engineering Books & Video). He can be contacted atmark@firestartraining.com.
