There seem to be diverging accounts within industry about what constitutes a “blower” vs. what constitutes a “fan.” If there is a consensus to be found, it seems that “blowers” are often referred to as such when they are arranged in a centrifuge or when they are regenerative. On the other hand, “fans” tend to be called “fans” when they are arranged radially, feature visible blades and are used for comparatively lighter-duty purposes. But the term “blower fans” just messes up the whole arrangement.
If you query Google’s image search for “blower fans,” you’ll see a lot of products that resemble each other pretty closely. The majority of the images from the top part of the selection are of centrifugal blowers (some floor driers, some ventilation blowers and other examples), though there are a few exceptions. But if you scroll down the page, the selection becomes more varied. You’ll see radial fans as well as axial fans, fans for use in warehouse shipping areas and blowers for use in industrial ventilation systems. It seems that “blower fans” is less of a precise, specific term than it is a colloquialism. It reminds me of when I worked landscaping one summer and a co-worker asked me to hand him the “cutting knife.”
None of this word confusion seems to get industry and commerce actually confused, though. After all, if you’re on the market for an industrial fan, you’re not going to just ask for a blower fan and find exactly what you want in your mailbox the week after. Instead, when it comes to individual fan and blower models, we’ve got words like “regenerative” and “direct drive” to help fan manufacturers and distributors know what we mean. “Blower fans” is just a term assigned to a genre of products; it’s a word used by people who know exactly what they’re talking about, but who don’t want to waste time being needlessly specific.