High flow closed loop hydraulic for snowblower

[fast*st]

So looking at all the snow has me thinking, would it be possible to add a pto driven 35gpm hydraulic pump and whip up a closed loop system with accumulator that combines fluid with the main hydraulic system. My thought is after the initial air purge there shouldn't be any issues, 1 inch hydraulic lines running front to back to the rear pump for supply and return.

it would be easier than having a huge hydraulic tank mounted on the 3pt hitch, less complicated might be better, share a small flow with the tractor for cooling and air purge with the main flow going through the blower and back.

It'd sure be nicer to have a loader mounted skid steer snow blower.

 

[aeblank]

I'd think you'd be creating too much heat in order to do what you are saying.
I know that I don't know enough about the "remotes" on a tractor to design a system (what inlet conditions does it like, what flow rate does it have, what heat rejection capacity does it have, etc. etc.) I was part of a system that does something similar with the reservoir, using a boost jet orifice to replenish lost fluid (case drains for pump and motor going back to reservoir). But we cooled ALL the flow.

all that said, I don't think the gain is much over the standalone system.
You're trading hooking up a 3-pt. device for hooking up hoses. Big deal.
Still a pump, still lots of plumbing.

If you could *neatly* and permanently mount the pump to a mid-PTO, mount the cooler on the blower somewhere (block of aluminum bolted to it that the flow goes through?) and permanently mount the quick disconnects....
THEN you'd have something.

 

[aeblank]

If you could *neatly* and permanently mount the pump to a mid-PTO, mount the cooler on the blower somewhere (block of aluminum bolted to it that the flow goes through?) and permanently mount the quick disconnects....
THEN you'd have something.

Not to quote myself, but dang, that's awesome.
Reservoir, cooler, and obviously motor attached to blower.
Pump attached to mid-pto (some risk there, make a guard?)
Small amount of plumbing attached to tractor.

Mid-PTO can be disengaged independently, so you can disengage it all summer long. If it is an adjustable pump, it would be zero displacement pushing against the quick disconnects. That's "safe" until the pump gets so hot it burns up. If it were constant flow (vs. constant pressure) then the blower could run at full RPM regardless of engine RPM. You'd only need to adjust the engine RPM for whatever the load is.

I wonder how many horsepower a blower takes. Rexroth (45cc/rev or 74cc/rev) constant flow pumps are reasonably small. They may not push enough horsepower though. Also the mid-pto doesn't have a bolt flange on it. (hmm, custom PTO with a bolt flange and an internal spline?).

Why can't a tractor have at least ONE remote that is "skidsteer like" with lots of flow/pressure (again, I don't have numbers)...?

 

[fast*st]

Right, that'd be simply wonderful, you have the low flow remotes on the stick and then a dedicated high flow remote. Std flow is usually 22-23 gpm and the high flow is 36-38 gpm @3500max for the bobcats if I recall. I'm not sure but I think the M series with the fancycab dropped the midship pto, a very useful feature. I wonder how many kw of heat you'd have to get rid of though with lines and all exposed to the weather, assuming you're not using it to blow manure in the spring time (have seen that done) the skid steer blowers usually have a set of electric remotes for the swivel and tilt of the chute, you could even have the return line dump through a large emptied out and welded shut hyd cyl, like a 3x40, put just above the auger for snow cooling though aluminum would be far better.

 

[aeblank]

I am literally going to pick up my L2195A (front mount blower) this weekend.
So, I won't be doing this, but it has my wheels turning.

If I could get some specs I could sketch something out. It could work, but the price point would be pretty steep. Maybe the goal would be to purchase a skidsteer type, and make a kit to convert it for use on a tractor.

 

[fast*st]

Yes, there are a lot of skid steer blowers out there and then they come with a wired remote and all the functions run off the supplied hydraulics.

How about a liquid heat exchanger, steal one of the heater hoses for cooling? then make up a nice bleed/make up oil supply tied into the return side plumbing and a crossover relief valve to limit the fun.

There's kits to add a front mount blower in the 10-15k range, seems a little steep but would love to look at one.

 

[North Idaho Wolfman]

The real key to make this kind of system work efficiently and over the long haul is cooling of the hydraulic fluid.
Skid steers use a very large fluid cooling core that is assisted by the engine fan, and a fairly large reservoir to give it bulk cooling.
You could put the cooler on the snowblower but if it gets loaded with snow it will effect the cooling ability.
When I do mine, I'm thinking I'll use steel pipe attached directly to the blower body and use that as a heat sink, so it won't be able to clog up fins on a cooler. I'm still looking at all options.

 

[aeblank]

The pump and motor combo is probably at least $2k.

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[fast*st]

Well, pump and motor if you're converting a PTO driven blower. The bobcat blowers just need flow and already have the correct attachment plate for the bigger tractors. My thought on the pipe or box tube section on the return side, say a 6x2x7' tube steel or aluminum section tucked up above the auger high enough to avoid any direct damage but close enough to get splashed with snow like a liquid cooled snow sled arrangement. The cooler would hold 3.6 gallons so the fluid should linger in there for 10 seconds?

What would the return pressure be on say 20' of 3/4" hose flowing 21 gpm, 2 feet/second

Surplus center has a 9.9 inch pump for $583. lines will be pricey though. The only other pto accessory is the mower so it'd almost be safe to leave the blower and pto on all winter. I was thinking it'd be a good idea to share fluid with the trans, push in and draw off a few gpm from a low pressure source just to help with cooling and expansion.

 

[skeets]

Man this is way over my head

 

[olthumpa]

Man this is way over my head

It's just one post above you

 

[North Idaho Wolfman]

Well, pump and motor if you're converting a PTO driven blower. The bobcat blowers just need flow and already have the correct attachment plate for the bigger tractors. My thought on the pipe or box tube section on the return side, say a 6x2x7' tube steel or aluminum section tucked up above the auger high enough to avoid any direct damage but close enough to get splashed with snow like a liquid cooled snow sled arrangement. The cooler would hold 3.6 gallons so the fluid should linger in there for 10 seconds?

What would the return pressure be on say 20' of 3/4" hose flowing 21 gpm, 2 feet/second

Surplus center has a 9.9 inch pump for $583. lines will be pricey though. The only other pto accessory is the mower so it'd almost be safe to leave the blower and pto on all winter. I was thinking it'd be a good idea to share fluid with the trans, push in and draw off a few gpm from a low pressure source just to help with cooling and expansion.

Sounds like a great plan! I too would go with taping into the tractor for added reservoir and cooling, if you do this you won't be able to use an accumulator but if the cooling will be better.
Your return pressure will be nil, all pressure will be lost at motor, the key to this is good lines and good fittings.
I would do seamless hard lines and keep the soft lines to a minimum.

 

[aeblank]

I need to do some math.....

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[fast*st]

Sounds like a great plan! I too would go with taping into the tractor for added reservoir and cooling, if you do this you won't be able to use an accumulator but if the cooling will be better.
Your return pressure will be nil, all pressure will be lost at motor, the key to this is good lines and good fittings.
I would do seamless hard lines and keep the soft lines to a minimum.

Interesting thought on using hard lines, I've never done work with them, sounds like for high pressure you'd want the .109 wall stuff. The pressure in the lines would be the friction losses on the return path, moving a lot of gpm will create a bit of drag. Are they normalized enough that you can braze tabs to them for securing and preventing vibrations?

 

[North Idaho Wolfman]

Hard lines have less resistance then soft lines, you can get mounting blocks to attach then to the frame, you never want them solid mounted as they will crack from the vibrations.

 

[fast*st]

Excellent suggestion, it seems most of the factory hard lines I've found have a clamp with a rubber pad and unsupported sections are pretty short for the bigger stuff.