Convert/Redo hydraulic snow pump

[fitterski]

I put this into service Xmas 2009 and it is now starting
its 8th season of abuse. By abuse I mean everything from
design to the blower detaching, breaking the electrical
harness and running away downhill into a ravine.

[1st post utube link not allowed]

# is zsgvwMYn0N0

But it works, and amongst *git-er-done* folk it's pretty
hard to argue with that!

Before digging into the beef I'll just mention that
my driveway/runway is 3000 feet long so that all
snow removal operations are strictly mission critical.
Not only must everything start and work in any conditions,
once going any midway hangup where in addition to
mission failure I also block the road can be very
expensive. Digital controls are because of this out
of the question. Instead of failing DOWN to total
service denial (my 2008 Tundra just did this recently)
good digital systems fail UP to a passthrough circuit
hardwired to protect fallback to purely mechanical
control. Unfortunately few consumer-level digital
systems are of this level in 2016.

So, on with the original main topic:

Problem is I want more power and because of weight
constraints that means going to the originally
dropped hydraulics option; namely, a separate engine
and pump powerpack and a hydraulic motored blower.
Another reason I want to maybe sidestep to this
approach is that I'm getting on in years and I may
have to backlevel to a truck mounted system. My 2008
Tundra will be put out to stud in a few years and by
then I want to have the new system proven, worn-in
and ready to be transplanted.

What I have works fine, the design objective was to blow
4-6 inches of dry snow 100 feet laterally at 15 km/h or
so. However wet snow isn't dry and sometimes there's a
lot more that 4 inches of it. Brilliant observation #2
is that the 8 years have taught me that when you fall
behind the curve then only one and no other solution is
necessary: not just overpowering but OBSCENE amounts of
overpowering. Dry snow gets pulverised to an undriveable
consistency around 150 feet per second which does not
apply to wet snow so I'm thinking 600rpm with torque
autoincreasing virtually unlimited on demand and an
additional spoolup option to around 1000rpm. I could
also drive the fan at 1000 all the time, and BTW the
proper name for a beast of this nature is not a snowblower
but a snow-pump, some people actually test theirs by
driving them into the sea ...to a stall depth of a few inches.

So the new design objective is to throw up to 8-9 inches
of wet snow at least 100 feet vertically at a similar or
15-20 km/hr clip behind a 7-foot wide auger.

The good news is that there are very few limits, I want
no less than 300hp on tap and the hyd. motor putting out
major fan torque between 600 & 900 rpm with no gearbox.
A gearbox IS possible but why bother when I can drive
the auger with another smaller high-torque motor and
simplify things in the process? Besides, a gearbox of
this capacity is 250lbs-$3k easy.

All suggestions are welcome, the first and foremost
question being the pump/motor combo size/type. I can
find and engine later, I can design a smaller/larger impeller.
Is the service longevity of piston type hyd. motors
good?

tia

 

[fitterski]

If I do the hydraulics thing than I have a few intial notions: the motor would be a Duramax LMM, the pump about 12 cu-in with a nominal system pressure of 2500psi @3000rpm drawing 285hp which should be good from that engine. The motor end is where a LOT of losses show up so with margins still protected and strictly on paper I figure 36 cu-in, 945 torque @1000rpm, down to about 180hp. Such a motor may be just a wet dream weight wise, nor will this give me 100 foot vertical throw but maybe half that. Getting 100 would require a non-hydraulic direct drive (current setup) which does remain one option for the time being but I may have to increase reduction to 3:1.



The current outstanding question is what is the limit lateral load on the flywheel of this engine?

 

[oldnslo]

For hydraulic drive have you considered going to higher pressures?

Rexroth makes fixed displacement A2FM motors in 250 cc, 355 cc, 500 cc. All of these will operate at 5,000 PSI and speeds up to 2,000 RPM depending on the size. They also make variable displacement A6VM motors in the same displacements for use if you wanted two speed option for wet vs dry snow.

At 285 HP you can drive a pump to provide around 85 GPM @ 5,000 PSI. a 125 cc pump at 2,500 RPM would produce 82.5 GPM. Depending on the brand of pump you may be able to get manual displacement control Vs electric.

I would run this in a closed loop circuit to reduce the reservoir size and limit losses from valving.

No idea on the Duramax flywheel loading.

 

[FatTire]

That's a cool machine. Maybe you should think about an old Unimog. Nothing digital. Just to clarify, are you serious about throwing wet snow vertically 100 feet? Or did you mean laterally?

 

[fitterski]

Thanks for responding oldnslow, I ain't so young or fast any more myself

5000 psi scares me, a pinhole leak can kill you at that pressure and DIY 300hp ANYTHING is a very violent environment. I may eventually have to re-evaluate but for now I'm still crunching the very basic formulas (been like 50 years since a few rudimentary air-force lessons & I've never touched hydraulics since!).

From what I see so far is that axial piston pump/motor is the most flexible and would easily accommodate my numbers (rpm-pressure-volume-torque). A closed system would save weight and since it would be for a SNOW blower, thermal dissipation should be OK although that may still require a radiator and THAT would be simpler with an unpressurised reservoir. I think I have already seen pumps in the 12 cu-in/2500psi range, the 36 cu-in motor not yet. It may bee too costly or inexistant.

Until now I had envisaged only fixed displacement pump/motor planning to modulate fan rpm +/- 600-1200rpm by changing engine/pump speed. I kind of do that now with the existing rig. The thing is I still have a LOT of learning to do. That 500cc @ 5k psi might be the one for me, I sure am going to bookmark it.

Some of my 'fishing' notes:

 

[fitterski]

That's a cool machine. Maybe you should think about an old Unimog. Nothing digital. Just to clarify, are you serious about throwing wet snow vertically 100 feet? Or did you mean laterally?

I already HAVE the 426 and giving it something to do in the winter actually helps to keep it oiled as it were. The initial idea was to have a radio controlled system that allows me to drop the blower and work with the loader at will. That, alas, flopped because the 24 channel radio set I bought from China picked up stray signals and engaged the starter while operating, twice! So the short of the long is that I scrubbed that idea but that's how it all started with the Cat. Also, there ARE plenty of stock machines, used even at very good prices but none of them are designed to toss snow very far and in my case that's imperative. Some very big industrials can do it but those cost more than my house.

As for the 100 feet I do that now, horizontally, downwind The vertical idea came after a few arguments about the math required so I then decided to simplify and talk vertical only! Actually I'd love to see a new sport come out of this, it would help pioneer some interesting mechanical solutions .....like THIS guy I just spotted today

Homemade truck snowblower (chevrolet Tracker) - YouTube

cannibalized tracker turning the blower with the fwd-driveshaft while a 3-holer in the trunk moves the wreck around

Hey, is that a twin-fan blower in your avatar? Is it yours? Looks like it's handling a mouthful easy. I'm lookin', it so happens that a fan is about he same weight as an auger. Are they driven by one hyd. motor?

 

[fitterski]

About the digitals, if I were to go strictly mechanical I was looking at a cummins 6BT, 200 horses would be ok. With hydraulics the losses add up so I need double at the pump, The Duramax is a very tightly engineered bull, someone I know is putting one into a small airplane. What I've heard from the grapevine is that up to the 2008-2009-2010 production year the last of those models the LMM can still be run with a more or less stock engine-control-module and some wiring work. I had also looked at the Cummins 5.0L-v8 but _ain't looking at that no more_

 

[oldnslo]

Fitterski,
FYI: Rexroth also makes those motors in a 750 cc & 1000 cc option. Price may be an obstacle though.

Can you use a lower RPM and larger diameter fan to get the tip speed you require? From my feeble old memory our Gehl hi-thro silage blower had a 54" diameter fan running at 540 RPM and you could easily fill 80 ft silos with 90 HP tractor.

 

[fitterski]

Fitterski,
FYI: Rexroth also makes those motors in a 750 cc & 1000 ...

The only comparison i can make is to what i can do with snow, with what i have. I don't have a mental handle on or feel for silage weight & mass. When i first started lotsa folks insisted that 540 rpm was "it", but that is only because most pto's are 540. I now run my 36" fan at up to 1000rpm, that's max with the 2.5:1 gearing due to approaching engine redline. It is very finely balanced and I think I could take it up to 1200-1400 but wouldn't wanna risk eating a mailbox post at that speed. The theoretical high limit would be trans sonic probably around 2200 rpm with a 48" fan. At that speed wearout would be a concern, extremely fine balancing also, and the snow would have to be fed very evenly. I don't know off hand the hp of my Deutz 4-holer, it's around 65hp and that starts huffing/puffiing quite easily. I "could" make another one but wouldn't want to go far past 40" because then I'd start getting into a dual auger box size and the associated weights.

My attack will be spread over 4 stages: first I'm going to try the engine as-is on my rig. I only need to respect the flywheel lateral load limit once i find it. I'll see how the gearbox can take that torque, it might just break. The present fan running maybe 1200 should already be quite an improvement. Step-2, I'll have to decide if I have enough horses doing nothing and maybe make new 40"-42" fan. The 3rd step will be the decision to go hydraulic, the 4th to move it all to another platform.

I looked at that 500cc motor and almost fell out of my chair when I saw the weight, 300lbs! The pump would probably be similar, plus a possible reservoir, plus the 150 lbs extra that the Duramax brings and I would be in a corner to make all that work on my loader bucket so the decision to go hydraulic will most likely be a concurrent one to change platform.

I could also try for a 70% capability reduction but don't really have a good engine in sight for that role at around 750lbs, plus the fundamental approach seeking to have 'obscene' amounts of power in reserve isn't really aiming to go with less

 

[FatTire]

As for the 100 feet I do that now, horizontally, downwind The vertical idea came after a few arguments about the math required so I then decided to simplify and talk vertical only! Actually I'd love to see a new sport come out of this, it would help pioneer some interesting mechanical solutions .....like THIS guy I just spotted today

Homemade truck snowblower (chevrolet Tracker) - YouTube

cannibalized tracker turning the blower with the fwd-driveshaft while a 3-holer in the trunk moves the wreck around

Hey, is that a twin-fan blower in your avatar? Is it yours? Looks like it's handling a mouthful easy. I'm lookin', it so happens that a fan is about he same weight as an auger. Are they driven by one hyd. motor?

That is a twin fan, made by the German company Beilhack. They are PTO driven. Engine for the blower is a Mercedes OM321A, 110 hp. I use this a few times a winter, not a lot.