Snow blower performance

[Dan33Klein]

Dutch, it does look pretty similar to the blower you listed.

 

[dnw64]

I'm wondering if the blower is setup for a 1000 rpm blower.

This was my first thought as well.

Assuming there is a chain/sprocket assembly from PTO to blower, count the teeth on input and output shafts and post them.

 

[Dan33Klein]

The pto shaft goes straight through the gear box to the impeller. Direct drive. But I will mark then accordingly and rotate the shaft to confirm this again

 

[James Eric]

I am also modifying a snowblower to fit on a tractor. I found that the impeller target speed should be 900-1000 rpm.

 

[Dan33Klein]

I am also modifying a snowblower to fit on a tractor. I found that the impeller target speed should be 900-1000 rpm.

I’m sure 900-1000 would be nice.
But I see no easy way to increase the rpm when I only have 540.
And increasing the speed of the impeller would require more hp... and I’m already short on that.

 

[jgayman]

I am also modifying a snowblower to fit on a tractor. I found that the impeller target speed should be 900-1000 rpm.

I don't quite understand your statement. The vast majority of all rear 3PH snow blowers drive the impeller directly from the PTO shaft. As such only blowers made specifically for a 1000 RPM PTO would run at that speed. All other rear blowers run at a PTO speed of 540 RPM which is by far the most common.

1000 RPM starts to become more common once you get over 75HP on the PTO.

 

[jgayman]

I’m sure 900-1000 would be nice.
But I see no easy way to increase the rpm when I only have 540.
And increasing the speed of the impeller would require more hp... and I’m already short on that.

If your blower is rated for 540 RPM you wouldn't want to run it at 1000 RPM. Doubling the speed of the impeller would also double the speed of the auger which would likely cause problems.

 

[James Eric]

If your blower is rated for 540 RPM you wouldn't want to run it at 1000 RPM. Doubling the speed of the impeller would also double the speed of the auger which would likely cause problems.

Sorry, I see now that he is using a rear mount blower. My blower is a front mount designed for the higher speeds.

 

[PILOON]

I知 sure 900-1000 would be nice.
But I see no easy way to increase the rpm when I only have 540.
And increasing the speed of the impeller would require more hp... and I知 already short on that.

My CUT has 3 PTO speeds, the 540 is pathetic and the 7XX is just nice.
I tried the 1000 and thought the blower would self destruct.
Now I can just imagine how the 7XX will perform when I fill the fan gaps with rubber flaps.

I occasionally go back to the 540 when I chew up frozen berms as there is more brute power and distance is not important.

One modification I did make was to bore the shear bolt holes from 1/4" up to 5/16" as the 1/4's tended to shear a bit to frequently to my liking.
I run grade 5 hardware for shear bolts as I find the shear or cut is cleaner while the 'ungraded' stretch and distort all while damaging the edges of the holes.
Also a twisted or distorted shear bolt is usually a bugger to drive out the remnants.

 

[Dave M7040]

I don't quite understand your statement. The vast majority of all rear 3PH snow blowers drive the impeller directly from the PTO shaft. As such only blowers made specifically for a 1000 RPM PTO would run at that speed. All other rear blowers run at a PTO speed of 540 RPM which is by far the most common.

1000 RPM starts to become more common once you get over 75HP on the PTO.

Usually the higher horsepower tractors, using 1,000 rpm pto's, use implements which slow the pto speed down to around 540 rpm once the power is at the implement.

The higher pto speed is just to allow more power transfer without using a larger diameter pto shaft.

This chart from Normand Commercial product line for tractors up to 350 Hp shows all blower fans are running at 540 rpm.
A speed reducer is recommended on the blower to reduce the pto speed from 1,000 to 540.

Dave M7040

 

[Dan33Klein]

Thanks for the post, I know the blower was designed for 540 rpm so I am fine there. Just need to re clearance the impeller and I’m sure the performance will increase drastically.
Even if I had a multi range PTO I would have to stay in 540 due to HP limitations.

Thanks for all your help!

 

[Amvcane]

You had said you are going to disassemble for painting. Before you remove the impeller I would measure what you would have to add to each blade of the impeller to bring the clearance to say 1/8”. Then weld the the appropriate piece of steel to each blade to do so. This leaves a smooth surface on the blade for the snow to slide on, no washers bolts or nuts in its path.

 

[Dan33Klein]

You had said you are going to disassemble for painting. Before you remove the impeller I would measure what you would have to add to each blade of the impeller to bring the clearance to say 1/8”. Then weld the the appropriate piece of steel to each blade to do so. This leaves a smooth surface on the blade for the snow to slide on, no washers bolts or nuts in its path.

Yes, I planned on either building up the edge of the impeller with weld and then fitting it to the housing tight.
Or cutting equal size pieces of plate steel and tacking them to be impeller tight with the housing on the leading edge. Then removing the impeller to finish welding them on nice.

 

[Dave M7040]

Yes, I planned on either building up the edge of the impeller with weld and then fitting it to the housing tight.
Or cutting equal size pieces of plate steel and tacking them to be impeller tight with the housing on the leading edge. Then removing the impeller to finish welding them on nice.

Plse let me throw some thoughts out to you before you get started. I have repeated them so many times, I have a file saved to paste.

There have been several times on this forum where owners of blowers they recently acquired complained in the same way you have. To their surprise, it has happened the blower was rotating backwards. It typically happens when a blower, designed for front use or front and rear use, is not installed correctly and reduction chain and sprockets are wrong.

I suggest investing a few dollars($20) in a laser tachometer will immediately show you the fan rpm's and, for future use the accuracy of your pto speed gauge which becomes important if you want to power a pto generator.
Amazon.com: Digital Photo Laser Tachometer Non Contact Tach RPM Meter: Automotive

Can I point out something that may change how you view blower throwing distance.

Imagine standing with a bucket of baseballs. The first test has you throwing them 100' in a fixed amount of time. Now increase the distance by 50% and throw the balls in the same amount of time.

Unless you are a star athlete, you will be much more fatigued throwing the same number of balls a greater distance. There is no free lunch either when it comes to snow blowers. Distance comes at the expense of requiring more power and fuel.

If you really need distance, then buy a blower where the drum rotates and the snow completely bypasses the chute and comes directly off the tip of the fan. This feature adds a lot to the price.
In heavy wet snow, blowing capacity of the RDX-102 is greatly increased as the snow can be discharged directly off the fan paddles versus all the way up through the center chute.
This video make the design function very easy to understand.

Normand N86-282HTR Side Discharging Snow SnowEquipmentDealer.com - YouTube

This photo from the Schulte web site shows how far the snow can be thrown with the side discharge

Schulte Industries Products


Gravely walk behind snow blowers have a feature where the drum and chute rotate so the snow is not being influenced by the chute and the distance the snow is thrown is much further,

Newer blower designs have improved fan performance by partially blocking the opening into the fan as shown in this photo

When choosing a snow blower, owners often forget about the importance of the angle that their pto shaft will have to operate at.

Measure the height of your tractor's pto shaft above ground. Now compare that measurement to the radius of the blower fan. Radius not diameter. Radius is 1/2 of the diameter so a 22" fan diameter would have an 11" radius.

If your pto shaft is say 15" above ground level, the height of the pto shaft at the blower end will be the radius of 11"

This means your pto shaft U joints are gong to be operating at an angle. The degree of the angle depends upon the vertical difference in height between the tractor pto and the center of the blower fan plus how close the blower is to the tractor.

Why this is important has to do with the life expectancy of the pto joints.

This chart shows how quickly the pto joint life decreases as the operating angle increases.

A pto angle of 5 degrees has a life expectancy of 450 hours.

Increase the pto joint angle to 25 degrees and the joint life is a very short 20 hours.

These figures can be disputed by owners who claim to have long life while having large pto joint angles. The designers of these shafts spend many hours testing and rating their products. I think it is wise to be guided by the designers ratings.

In the end, it is your blower and of course plse do what you feel is best considering all the advice you have received.
I have been very fortunate in life to have been educated as a mechanical engineer and have spent 40+ years dealing with issues of performance and power.
There are many members on this forum who are wiser than I am having spent their lives learning by doing and their advice has much weight too.

Dave M7040

 

[Dan33Klein]

Dave,
Thanks for all of that. I appreciate the knowledge. I have never seen a rotating drum like that before. Pretty slick.
I am going to start with clearance for the impeller and maybe even welding a plate on the front like your picture showed.

I don’t need to throw the snow 100’ but farther than puking it right off the side of the blower would be nice.
We don’t get the snow where I’m at like we used to anyway. The blower won’t be used to much. Usually we just get 3-4 inch snows. The plow will take care of that

 

[Phil48]

In early decembre I welded 3/8 thick plate to reduce clearance (1/8 to 1/16). After two month of "nice" storm, I guess I have an extra 6 to 8 feet when I use it. The Martin is 5 year old, newer model have larger funnel and tighter fit for the second phase, evolution...

It does help!

Phil

 

[Dave M7040]

Dave,
Thanks for all of that. I appreciate the knowledge. I have never seen a rotating drum like that before. Pretty slick.
I am going to start with clearance for the impeller and maybe even welding a plate on the front like your picture showed.

I don’t need to throw the snow 100’ but farther than puking it right off the side of the blower would be nice.
We don’t get the snow where I’m at like we used to anyway. The blower won’t be used to much. Usually we just get 3-4 inch snows. The plow will take care of that

Dan

Don't weld the triangle shaped piece of steel rather bolt it on.
It will have to come off if you ever need to remove the fan.

Leaking gear box seals require fan removal.

The area of your blower I am most interested in is covered in snow in your photos.

The area behind the fan where the pto connects.

Could you please take a few photos of that area

Dave M7040

 

[Dan33Klein]

Dave, I will get a few more tomorrow.
In fact, wednesday I am going to start the tear down of the blower. That will be a good time to get pictures. It seems like the fan is just connected to the gear box shaft with 1 bolt. I am guessing the shaft/fan is keyed? My buddy said he would bet I’ll never get the the fan off the shaft. I have no idea how old this blower is. If it’s never been off it probably won’t come off.

Also, is there a rule of thumb for how much of the impeller should be covered?

Thanks

 

[Dan33Klein]

Phil,

How big is your blower?
Looks like your fan is pretty decent size diameter! It should throw snow nice.
How many hp is your Kioti?

 

[Dave M7040]

Dave, I will get a few more tomorrow.
In fact, wednesday I am going to start the tear down of the blower. That will be a good time to get pictures. It seems like the fan is just connected to the gear box shaft with 1 bolt. I am guessing the shaft/fan is keyed? My buddy said he would bet I’ll never get the the fan off the shaft. I have no idea how old this blower is. If it’s never been off it probably won’t come off.

Also, is there a rule of thumb for how much of the impeller should be covered?

Thanks

Dan

I am with your buddy on the fan removal.

Unless your gearbox is leaking oil, best to leave the fan where it is.

The ones I have removed were like a war.

The last one: I ended up taking it to a big metal fab shop and they made special pullers etc to get the fan off.

Over 10 tons of pulling. So much so the frame of the blower was bending. The bill was close to $1,000.

I do not know of any design factors you could use with the triangular plate which is the beauty of bolting it on.
You could start with sheet metal that you can easily cut. Even plywood. Go bigger than you think, then start reducing the size of the triangle.
You need to stand in front of the blower and even video the snow movement in the fan.

In the end, a piece of 1/8" plate to finish the job.

You want to contain the snow on the fan blades as they approach the discharge area of the fan.

Dave