Deleted
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Post by Deleted on Aug 6, 2013 17:46:22 GMT -5
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Post by Rick M. on Aug 8, 2013 0:55:44 GMT -5
Wow, that thing is a monster!
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Post by Jordan U on Oct 10, 2014 11:59:58 GMT -5
That is quite odd indeed, I wonder how good its performance is...
How much were they asking for it?
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Dob
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Post by Dob on Oct 13, 2014 14:50:10 GMT -5
That is a Herman Nelson exhaust fan. Performance for these was probably very good. Slow turning so it would be quiet and deep pitched blades so it would move a lot of air.
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Post by Jordan U on Oct 15, 2014 21:05:44 GMT -5
That is a Herman Nelson exhaust fan. Performance for these was probably very good. Slow turning so it would be quiet and deep pitched blades so it would move a lot of air. Sounds like this is a quality piece. About how old do you think it is? I've never heard of the brand Herman Nelson before. I assme its not the same modern Nelson brand that puts out sprinklers and things of that natue? |
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Dob
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Posts: 336
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Post by Dob on Oct 16, 2014 8:07:29 GMT -5
That is a Herman Nelson exhaust fan. Performance for these was probably very good. Slow turning so it would be quiet and deep pitched blades so it would move a lot of air. Sounds like this is a quality piece. About how old do you think it is? I've never heard of the brand Herman Nelson before. I assme its not the same modern Nelson brand that puts out sprinklers and things of that natue? I would say it's probably from the 40's. I don't know anything about sprinklers so I am not certain. |
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Post by Jordan U on Oct 16, 2014 8:09:06 GMT -5
Sounds like this is a quality piece. About how old do you think it is? I've never heard of the brand Herman Nelson before. I assme its not the same modern Nelson brand that puts out sprinklers and things of that natue? I would say it's probably from the 40's. I don't know anything about sprinklers so I am not certain. Nelson currently makes garden products, the only product I have from them is a lawn sprinkler. I suppose they could have produced these fans for greenhouses. If I remember later, I'll try to do some research on the brands. I doubt they're the same. |
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Dob
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Post by Dob on Oct 16, 2014 8:37:17 GMT -5
I have found very little regarding Herman Nelson, so far.
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Post by Deleted on Oct 16, 2014 17:23:33 GMT -5
i was told/heard that the same company also made a 3 bladed version with the same blades and all.
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Dob
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Post by Dob on Oct 16, 2014 18:02:17 GMT -5
They did make a 3 blade version. I believe only in larger sizes though. Probably over 30" was 3 blade.
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Post by Jordan U on Oct 17, 2014 9:37:08 GMT -5
They did make a 3 blade version. I believe only in larger sizes though. Probably over 30" was 3 blade. I imagine the 3 blades version would move a ton of air. |
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Dob
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Posts: 336
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Post by Dob on Oct 17, 2014 19:17:43 GMT -5
They did make a 3 blade version. I believe only in larger sizes though. Probably over 30" was 3 blade. I imagine the 3 blades version would move a ton of air. The extra blade allows it to turn at a slower speed while moving a good amount of air. Large fans like this can only spin so fast. A well designed blade doesn't need more wings for more air flow, just better pitch. Fresh'nd-Aire is a good example of this. I could get into blade construction details....but I'd rather not. It's a loooooooooong subject. Edit: I originally theorized that the maximum pitch a blade can have is 45 degrees AT MOST. I have since changed my theory to roughly 40 degrees, maybe less. A blade pitched at 45 degrees will start to blow air sideways instead of forward. This would cause cavitation issues, especially in enclosed spaces. You would think that a blade with pitch this steep would be excellent for air flow at low RPMs, I am starting to think otherwise. Most deeply pitched blades are about 33 degrees of pitch, which is pretty steep. Most I have seen is probably about 38 degrees? I haven't measured... This really should be it's own topic. |
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Post by Jordan U on Oct 17, 2014 22:22:32 GMT -5
I imagine the 3 blades version would move a ton of air. The extra blade allows it to turn at a slower speed while moving a good amount of air. Large fans like this can only spin so fast. A well designed blade doesn't need more wings for more air flow, just better pitch. Fresh'nd-Aire is a good example of this. I could get into blade construction details....but I'd rather not. It's a loooooooooong subject. Edit: I originally theorized that the maximum pitch a blade can have is 45 degrees AT MOST. I have since changed my theory to roughly 40 degrees, maybe less. A blade pitched at 45 degrees will start to blow air sideways instead of forward. This would cause cavitation issues, especially in enclosed spaces. You would think that a blade with pitch this steep would be excellent for air flow at low RPMs, I am starting to think otherwise. Most deeply pitched blades are about 33 degrees of pitch, which is pretty steep. Most I have seen is probably about 38 degrees? I haven't measured... This really should be it's own topic. From my knowledge of aerodynamics (granted its not that advanced) 45 degrees would be the cutoff for blowing air strait forwards. I'm sure depending on the exact blade shape, say something like an ILG fan, you can probably push that boundary, but generally speaking more or less 40 degrees is probably where most of them stop An interesting topic though, may be worth starting a thread on. |
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Post by Deleted on Oct 18, 2014 19:44:36 GMT -5
i agree about this so called blade pitch topic,hope one of yall create a thread for it
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Post by Jordan U on Oct 18, 2014 21:53:05 GMT -5
i agree about this so called blade pitch topic,hope one of yall create a thread for it I'll create it, but I don't know where it should go, portable fan general? |
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