Snow Blower Performance

[hwp]

I use two or three passes of hard weld along the tip of each blade and then carefully grind them down to fit the drum. I check the fit with a feeler gauge. It takes a bit of time. The other thing to check is the balance of the impeller. It is sometimes necessary to add a spot of weld to the back of a blade and then grind it down as necessary to keep the impeller balanced.

 

[smfcpacfp]

The gap between the impeller and the drum affects the ability of the impeller to carry the snow to the point of discharge. The drums on most snowblowers are not round but slightly oval. The critical sweep is from bottom dead centre to the point of discharge 90 degrees later - the rest doesn't matter.

Just a minor point but wouldn't that be 180 degrees?

 

[Industrial Toys]

I thought about messing about with a mig welder and grinder.
Probably not a good idea for balance!

I would get someone to make me a whole new impeller,
if I knew for sure it would be a marked improvement!

 

[hwp]

Just a minor point but wouldn't that be 180 degrees?

No, the point of discharge is where the blade becomes horizontal and the wall of the drum is vertical opening into the exit passage . The snow always wants to move to the outer edge of the blades so at the point where the exit passage intersects with the drum the snow will move up the exit passage to the discharge chute.

On many snow blowers there is a restriction plate at the transition from the exit passage to the discharge chute. The larger the hole in that restriction plate, the better the snowblower will perform. Similarly, the lower the friction in the discharge chute the better the performance will be.

 

[RFB]

hwp,

Just thinking out loud, but instead of steel, what to do think of using a system of replaceable polyurethane edges on the fan blades (similar to the pu snow plow edges) so that when wear becomes "X" dimension, old edges off, new edges on (or even adjustable and moved back into correct tolerance).

 

[Industrial Toys]

I would really like to understand this. If one actually understands how things work, one is better and better in a position to tackle almost anything! Just being told something is as it is, isn't good enough for me!

If it is the centrifugal forces that cause the snow to be ejected, then why would clearance be such an issue. It's not like you want to build as perfect an air blower as possible and then just substitute snow for air.

To my way of thinking, fan diameter and speed would be the most critical parameters, and yet almost all rear mount blowers run at the same 540 RPM max, and yet some as I have noted, work really well, at much lower then
full PTO speed.

Does anybody know what other thread pertains to this subject?
Also just as a side note. How can one keep track of ones threads
anbd posts on this site?

Thanks

 

[RFB]

log in, and then click on "My home". you will go right to your "subscribed" threads.

 

[Industrial Toys]

How would one go about balancing the impeller?

 

[RFB]

I am willing to postulate that impeller balance is not very critical.

The mass of the impeller on my blower is fairly large (27 inch fan blades, 3/8 inch steel with cross-bracing), and PU edges would be very small added mass to that overall.

Also, the varying masses of snow load and consistency, (ice, slush, wet and dry snow) must be part of the design tolerance, so that balance must be a relative term.

 

[doxford jim]

Hi Guys,

I am replying to this thread even though the subject is two years old.

I have just picked up a good sound used Allied Farm King 73" snow blower. It is made of heavy gauge material and I think, would be considered a commercial unit.

When I saw it being used, it threw snow only 15ft maybe 20ft. I noticed that someone in the past, had built up the fan edges with rod (look to be hard surfacing material) - I assumed, to prevent wearing. I wasn't aware of the clearance factor and will now go down and check out the impeller clearance. Building up and grinding to achieve say 0.015 to 0.020" clearance could easily be achieved this way.

Thx for the tip - I might get it to pump the snow thirty feet or more if I am lucky. I am assuming it is made with the PTO 540rpm operating speed in mind. I can't see any harm in going faster to 740RPM (I have dual speed PTO), which should improve net performance if clearances are right.

I will post the results of my check and mods if any. I sure would like to get a real good performance. I think most owners are overly generous with their estimates of how far the snow gets thrown, without realizing it. Then newbies end up having unrealistic expectations of what to expect from their machines. Of course technique is another variable to consider.

Thx

Jim