Why do blowers do better on a full load tham when half filled?

   / Why do blowers do better on a full load tham when half filled? #1  
C

CalG

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Has anyone done a study of what goes on?

Seems like a blower should blow air if it's not filled with snow...but we all observe, this is not the case. Chutes choke...etc..

What would be the physics?
 
   / Why do blowers do better on a full load tham when half filled? #2  
Snow is much heavier than air so it has a lot more momentum at a given speed. Like throwing a snowball vs. a handful of powder.
 
   / Why do blowers do better on a full load tham when half filled? #3  
CalG said:
Has anyone done a study of what goes on?

Seems like a blower should blow air if it's not filled with snow...but we all observe, this is not the case. Chutes choke...etc..

What would be the physics?
Click to expand...


=================================================================================

A couple of things:

The snow caster is filled by the forward motion of the implement carrier.

Friction and heat are created by the conveying of the snow by the cross
auger and the impeller in the case of a two stage unit creating resistance.

These crazy three stage units are a waste of money and I defy anyone to
explain away why they are better, THEY ARE NOT because of the inherent
inefficiency of the open cross auger design with the worm gear design.

Snow builds up in front of two stage snow casters simply because of the open auger
design(this does not occur with single stage snow casters-its in and out. IT pushes the
snow out in front of it at all times rather than meter a certain amount to the center of
the snow caster which is MOVING FORWARD.

A single or two stage snow caster will create a pressure gradient whether
it is full or not as air is being forced out of the chute, into the spout
and then out.

A single stage snow caster is more efficient as it removes the snow
ahead of it with one motion with higher torque delivered to the high
speed cross auger that conveys the snow to the center paddle where
it is ejected out of the chute and spout.

The open cross auger designed units are easier to build and cost less to build.

I am still waiting to see a two stage snow caster with a solid cross auger
like the old single stage units on old the cub cadets/simplicity tractors-post 1969
or a well built single stage front or rear mount.

The good snow blowers are single stage units with either a high speed cross auger
with ripping teeth in the single stage cross auger or the cross auger used for the
two stage units with Yamaha and BCS providing the best design in the home owner
market.


This method requires much more horsepower and torque but
The single stage four "scoop" single stage units with an ice and snow cutting propeller mounted in a wing plow cutting the snow into its smallest fraction making it easier to cast away.
 
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   / Why do blowers do better on a full load tham when half filled? #4  
Although not a direct reply to your question, snow blowers with a rotating drum do an amazing job at throwing snow.
You find this feature on commercial blowers like ones built by Pronovost.
You see them at work on air port runways.
Gravely had one for their walk behind units.
With the snow just leaving the tip of the fan and not having to pass through a restricting chute the difference is amazing.
Look at the two minute mark of this video.
https://www.youtube.com/watch?v=rQIsFQR2tuA
Dave M7040
 
   / Why do blowers do better on a full load tham when half filled? #5  
Some blowers just suck......

My Lorenz has never failed me.
 
   / Why do blowers do better on a full load tham when half filled? #6  
I have both, a single stage WH/Toro that is near new condition and an old 2 stage Gravely walk behind blower that has thrown some snow in its time. Both work well and even in wetter snow the single stage will keep right in there with the two stage (single doesn't toss it as far, but 20/30' is good enough for me), I attribute this to the single being like new and the two stage is no spring chicken, many old blowers have worn augers and impellers, they lose clearance between the impeller and housing or in the case of a single the housing and cups and they no longer are able to create that pressure gradient, couple that with rust on surfaces that need to be smooth and they become inefficient and contribute greatly to the clog thing,, drive pulleys and belts also wear and rpms to the implement are not what they should creating even more problems, couple all things together and you certainly have a headache with a blower,,, and then some snows are just darn difficult to blow no matter single or two stage, new or old.
 
   / Why do blowers do better on a full load tham when half filled? #7  
js5020 said:
I have both, a single stage WH/Toro that is near new condition and an old 2 stage Gravely walk behind blower that has thrown some snow in its time. Both work well and even in wetter snow the single stage will keep right in there with the two stage (single doesn't toss it as far, but 20/30' is good enough for me), I attribute this to the single being like new and the two stage is no spring chicken, many old blowers have worn augers and impellers, they lose clearance between the impeller and housing or in the case of a single the housing and cups and they no longer are able to create that pressure gradient, couple that with rust on surfaces that need to be smooth and they become inefficient and contribute greatly to the clog thing,, drive pulleys and belts also wear and rpms to the implement are not what they should creating even more problems, couple all things together and you certainly have a headache with a blower,,, and then some snows are just darn difficult to blow no matter single or two stage, new or old.
Click to expand...
my old case 448 had a 48" single stage. It sucked until I moded the thing. Increases gear size by 4 teeth increasing speed significantly. Major difference. It was great at blowing wet heavy slushy snow.

Sent from my iPhone 5s 64Gb using TractorByNet
 
   / Why do blowers do better on a full load tham when half filled? #8  
The snow is not blown. It is thrown. The impeller is not optimized as a blower. It is for throwing mass. The more you can get into it the better the discharge stream -- up to the limit of drive power.
 
   / Why do blowers do better on a full load tham when half filled?
  • Thread Starter
#9  
   / Why do blowers do better on a full load tham when half filled? #10  
The backplate is generally round so that it doesnt let snow collect behind it.

Aaron Z
 
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